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Title: Soap-Making Manual

A Practical Handbook on the Raw

Materials, Their

Manipulation, Analysis and

Control in the Modern Soap Plant.

Author: E. G. Thomssen

Release Date: October 22, 2010 [EBook

#34114]

Language: English

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Soap-MakingManual

A practical handbook on theraw materials, their

manipulation, analysis andcontrol in the modern soap

plant.

By

E. G. Thomssen, Ph. D.

ILLUSTRATED

NEW YORK

D. VAN NOSTRAND COMPANY

EIGHT WARREN STREET

1922

COPYRIGHT 1922

BY


Printed in the United States of America

PREFATORY NOTE.The material contained in this workappeared several years ago in serialform in the American Perfumer andEssential Oil Review. Owing to thenumerous requests received, it has beendecided to now place before thoseinterested, these articles in book form.While it is true that the workspertaining to the soapmaking industryare reasonably plentiful, books arequite rare, however, which, in a briefvolume, will clearly outline theprocesses employed together with thenecessary methods of analyses from a

purely practical standpoint. In the workpresented the author has attempted tobriefly, clearly, and fully explain themanufacture of soap in such languagethat it might be understood by all thoseinterested in this industry. In manycases the smaller plants find itnecessary to dispense with the servicesof a chemist, so that it is necessary forthe soapmaker to make his own tests.The tests outlined, therefore, are givenas simple as possible to meet thiscondition. The formulae submitted areauthentic, and in many cases are nowbeing used in soapmaking.

In taking up the industry for survey ithas been thought desirable to firstmention and describe the raw materials

used; second, to outline the processesof manufacture; third, to classify themethods and illustrate by formulae thecomposition of various soaps togetherwith their mode of manufacture;fourth, to enumerate the variousmethods of glycerine recovery,including the processes ofsaponification, and, fifth, to give themost important analytical methodswhich are of value to control theprocess of manufacture and todetermine the purity and fitness of theraw material entering into it.

It is not the intention of the author togo into great detail in this work, nor tooutline to any great extent thetheoretical side of the subject, but

rather to make the work as brief aspossible, keeping the practical side ofthe subject before him and not goinginto concise descriptions of machineryas is very usual in works on thissubject. Illustrations are merely addedto show typical kinds of machineryused.

The author wishes to take thisopportunity of thanking Messrs. L. S.Levy and E. W. Drew for the reading ofproof, and Mr. C. W. Aiken of theHouchin-Aiken Co., for his aid inmaking the illustrations a success, aswell as others who have contributed inthe compiling of the formulae forvarious soaps. He trusts that this workmay prove of value to those engaged in

soap manufacture.

E. G. T.

January, 1922

Transcriber's note: This is aseries of articles collectedinto a book. There aredifferences in spelling andpunctuation in the differentchapters (e.g. cocoanut inone chapter and coconut inanother). These differenceswere left in the text as theyappeared.

TABLE OFCONTENTS.

CHAPTER I. Page.

RAW MATERIALS USED IN SOAP MAKING 1-30

1. Soap Defined 1

2. Oils and Fats 1-2

3. Saponification Defined 2-3

4. Fats and Oils Used in Soap

Manufacture 3-4Fullers' Earth Process for

Bleaching Tallow 4-6Method for Further Improvement

of Color in Tallow 6Vegetable Oils 6-9Chrome Bleaching of Palm Oil 9-

12Air Bleaching of Palm Oil 12-16

5. Rancidity of Oils and Fats 16-18Prevention of Rancidity 18

6. Chemical Constants of Oils andFats 18-19

7. Oil Hardening or Hydrogenating19-21

8. Grease 21-22

9. Rosin (Colophony, Yellow Rosin,Resina) 22-23

10. Rosin Saponification 23-24

11. Naphthenic Acids 24-25

12. Alkalis 25-26Caustic Soda 26Caustic Potash 26-28Sodium Carbonate (Soda Ash) 28-

29Potassium Carbonate 29

13. Additional Material Used in

Soap Making 29-30

CHAPTER II.

CONSTRUCTION AND EQUIPMENT OF A SOAP

PLANT 31-34

CHAPTER III.

CLASSIFICATION OF SOAP MAKING METHODS

35-46

1. Full Boiled Soaps 36-42

2. Cold Process 43-44

3. Carbonate Saponification 45-46

CHAPTER IV.

CLASSIFICATION OF SOAPS 47-104

1. Laundry Soap 48Semi-Boiled Laundry Soap 49-50Settled Rosin Soap 50-54

2. Chip Soap 54-55Cold Made Chip Soap 55-56Unfilled Chip Soap 56

3. Soap Powders 56-59Light Powders 60-61

4. Scouring Powders 61

5. Scouring Soap 61-62

6. Floating Soap 62-65

7. Toilet Soap 65-68Cheaper Toilet Soaps 68-69Run and Glued-up Soaps 69-71Curd Soap 71-72Cold Made Toilet Soaps 72-73Perfuming and Coloring Toilet

Soaps 73-75Coloring Soap 75-76

8. Medicinal Soaps 76-77Sulphur Soaps 77Tar Soap 77

Soaps Containing Phenols 77-78Peroxide Soap 78Mercury Soaps 78Less Important Medicinal Soaps

78-79

9. Castile Soap 79-81

10. Eschweger Soap 81-82

11. Transparent Soap 82-84Cold Made Transparent Soap 84-

87

12. Shaving Soaps 87-90Shaving Powder 90Shaving Cream 90-93

13. Pumice or Sand Soaps 93-94

14. Liquid Soaps 94-95

15. Use of Hardened Oils in ToiletSoaps 96-98

16. Textile Soaps 98Scouring and Fulling Soaps for

Wool 98-100Wool Thrower's Soap 100-101Worsted Finishing Soaps 101Soaps Used in the Silk Industry

101-103Soaps Used for Cotton Goods 103-

104

17. Sulphonated Oils 104-105

CHAPTER V.

GLYCERINE RECOVERY 105-126

1. Methods of Saponification 105-106

Recovery of Glycerine fromSpent Lye 106-113

Twitchell Process 113-118Autoclave Saponification 118Lime Saponification 118-120Acid Saponification 120-121Aqueous Saponification 121Splitting Fats with Ferments

121-123Krebitz Process 123-125

2. Distillation of Fatty Acids 125-126

CHAPTER VI.

ANALYTICAL METHODS 127-164

1. Analysis of Oils and Fats 128Free Fatty Acids 128-130Moisture 130Titer 130-132Determination of Unsaponifiable

Matter 132-133Test for Color of Soap 133-134Testing of Alkalis Used in Soap

Making 134-137

2. Soap Analysis 137-138Moisture 138-139Free Alkali or Acid 139-142Insoluble Matter 143Starch and Gelatine 143-144Total Fatty and Resin Acids 144Determination of Rosin 144-147Total Alkali 147-148Unsaponifiable Matter 148Silica and Silicates 148-149Glycerine in Soap 149-150Sugar in Soap 150

3. Glycerine Analysis 150-151Sampling 151Analysis 151-154Acetin Process for the

Determination of Glycerol 155-156The Method 156-159Ways of Calculating Actual

Glycerol Contents 159-160Bichromate Process for Glycerol

DeterminationReagents Required 160-161

The Method 161-162Sampling Crude Glycerine 162-

164

CHAPTER VII

STANDARD METHODS FOR THE SAMPLING AND

ANALYSIS OF COMMERCIAL FATS AND OILS

165-195

1. Scope, Applicability andLimitations of the Methods 165-166

Scope 165Applicability 166Limitations 166Sampling 166-169Tank Cars 166-167Barrels, Tierces, Casks, Drums,

and Other Packages 168

2. Analysis 169-183Sample 169Moisture and Volatile Matter 170-

172Insoluble Impurities 172-173Soluble Mineral Matter 173Free Fatty Acids 174Titer 174-175

Unsaponifiable Matter 176-177Iodine Number-Wijs Method 177-

181Saponification Number

(Koettstorfer Number) 181Melting Point 181-182Cloud Test 182-184

3. Notes of the Above Methods 184-196

Sampling 183Moisture and Volatile Matter 184-

187Insoluble Impurities 187Soluble Mineral Matter 187-188Free Fatty Acid 188-189Titer 189Unsaponified Matter 190-193

Melting Point 193-196

Plant and Machinery 198-219Illustrations of Machinery and

Layouts of the Plant of a Modern SoapMaking Establishment 198-219

Appendix 219-237

Useful Tables

Index 239

CHAPTER I

Raw Materials Used in SoapMaking.

Soap is ordinarily thought of as thecommon cleansing agent well known toeveryone. In a general and strictlychemical sense this term is applied tothe salts of the non-volatile fatty acids.These salts are not only those formedby the alkali metals, sodium andpotassium, but also those formed bythe heavy metals and alkaline earths.Thus we have the insoluble soaps of

lime and magnesia formed when weattempt to wash in "hard water"; againaluminum soaps are used extensivelyin polishing materials and to thickenlubricating oils; ammonia or "benzine"soaps are employed among the drycleaners. Commonly, however, whenwe speak of soap we limit it to thesodium or potassium salt of a higherfatty acid.

It is very generally known that soap ismade by combining a fat or oil with awater solution of sodium hydroxide(caustic soda lye), or potassiumhydroxide (caustic potash). Sodiumsoaps are always harder than potassiumsoaps, provided the same fat or oil isused in both cases.

The detergent properties of soap aredue to the fact that it acts as an alkaliregulator, that is, when water comesinto contact with soap, it undergoeswhat is called hydrolytic dissociation.This means that it is broken down bywater into other substances. Just whatthese substances are is subject tocontroversy, though it is presumedcaustic alkali and the acid alkali salt ofthe fatty acids are formed.

OILS AND FATS.

There is no sharp distinction betweenfat and oil. By "oil" the layman has theimpression of a liquid which at warmtemperature will flow as a slippery,

lubricating, viscous fluid; by "fat" heunderstands a greasy, solid substanceunctuous to the touch. It thus becomesnecessary to differentiate the oils andfats used in the manufacture of soap.

Inasmuch as a soap is the alkali salt ofa fatty acid, the oil or fat from whichsoap is made must have as aconstituent part, these fatty acids.Hydrocarbon oils or paraffines,included in the term "oil," are thususeless in the process of soap-making,as far as entering into chemicalcombination with the caustic alkalis isconcerned. The oils and fats whichform soap are those which are acombination of fatty acids andglycerine, the glycerine being obtained

as a by-product to the soap-makingindustry.

NATURE OF A FAT OROIL USED IN SOAPMANUFACTURE.

Glycerine, being a trihydric alcohol,has three atoms of hydrogen which arereplaceable by three univalent radicalsof the higher members of the fattyacids, e. g.,

OH ORC3H5

OH+ 3 ROH = C3H5

OR+ 3H2O

OH OR

Glycerine plus 3 Fatty Alcohols equalsFat or Oil plus 3 Water.

Thus three fatty acid radicals combinewith one glycerine to form a trueneutral oil or fat which are calledtriglycerides. The fatty acids whichmost commonly enter into combinationof fats and oils are lauric, myristic,palmitic, stearic and oleic acids andform the neutral oils or triglyceridesderived from these, e. g., stearin,palmatin, olein. Mono and diglyceridesare also present in fats.

SAPONIFICATIONDEFINED.

When a fat or oil enters into chemicalcombination with one of the caustichydrates in the presence of water, theprocess is called "saponification" andthe new compounds formed are soapand glycerine, thus:

OR OH

C3H5 OR+ 3 NaOH =C3H5

OH + 3NaOR

OR OH

Fat or Oil plus 3 Sodium Hydrateequals Glycerine plus 3 Soap.

It is by this reaction almost all of thesoap used today is made.

There are also other means of

saponification, as, the hydrolysis of anoil or fat by the action of hydrochloricor sulfuric acid, by autoclave and byferments or enzymes. By these latterprocesses the fatty acids and glycerineare obtained directly, no soap beingformed.

FATS AND OILS USED INSOAP MANUFACTURE.

The various and most important oilsand fats used in the manufacture ofsoap are, tallow, cocoanut oil, palm oil,olive oil, poppy oil, sesame oil, soyabean oil, cotton-seed oil, corn oil andthe various greases. Besides these the

fatty acids, stearic, red oil (oleic acid)are more or less extensively used.These oils, fats and fatty acids, whilethey vary from time to time and tosome extent as to their color, odor andconsistency, can readily bedistinguished by various physical andchemical constants.

Much can be learned by one, whothrough continued acquaintance withthese oils has thoroughly familiarizedhimself with the indications of a goodor bad oil, by taste, smell, feel andappearance. It is, however, not well forthe manufacturer in purchasing todepend entirely upon these simplertests. Since he is interested in the yieldof glycerine, the largest possible yield

of soap per pound of soap stock and thegeneral body and appearance of thefinished product, the chemical testsupon which these depend should bemade. Those especially important arethe acid value, percentageunsaponifiable matter and titer test.

A short description of the various oilsand fats mentioned is sufficient fortheir use in the soap industry.

Tallow is the name given to the fatextracted from the solid fat or "suet" ofcattle, sheep or horses. The qualityvaries greatly, depending upon theseasons of the year, the food and age ofthe animal and the method ofrendering. It comes to the market under

the distinction of edible and inedible, afurther distinction being made incommerce as beef tallow, muttontallow or horse tallow. The betterquality is white and bleaches whiterupon exposure to air and light, thoughit usually has a yellowish tint, a welldefined grain and a clean odor. Itconsists chiefly of stearin, palmitin andolein. Tallow is by far the mostextensively used and important fat inthe making of soap.

In the manufacture of soaps for toiletpurposes, it is usually necessary toproduce as white a product as possible.In order to do this it often is necessaryto bleach the tallow beforesaponification. The method usually

employed is the Fuller's Earth process.

FULLER'S EARTHPROCESS FOR

BLEACHING TALLOW.

From one to two tons of tallow aremelted out into the bleaching tank.This tank is jacketed, made of iron andprovided with a good agitator designedto stir up sediment or a coil providedwith tangential downward openingperforations and a draw-off cock at thebottom. The coil is the far simplerarrangement, more cleanly and lesslikely to cause trouble. By thisarrangement compressed air which is

really essential in the utilization of thepress (see later) is utilized foragitation. A dry steam coil in anordinary tank may be employed inplace of a jacketed tank, which lessensthe cost of installation.

The tallow in the bleaching tank isheated to 180° F. (82° C.) and tenpounds of dry salt per ton of fat usedadded and thoroughly mixed byagitation. This addition coagulates anyalbumen and dehydrates the fat. Thewhole mass is allowed to settle overnight where possible, or for at leastfive hours. Any brine which hasseparated is drawn off from the bottomand the temperature of the fat is thenraised to 160° F. (71° C).

Five per cent. of the weight of thetallow operated upon, of dry Fuller'searth is now added and the whole massagitated from twenty to thirty minutes.

The new bleached fat, containing theFuller's earth is pumped directly to apreviously heated filter press and theissuing clear oil run directly to the soapkettle.

One of the difficulties experienced inthe process is the heating of the pressto a temperature sufficient to preventsolidification of the fat without raisingthe press to too great a temperature. Toovercome this the first plate is heatedby wet steam. Air delivered from ablower and heated by passage through a

series of coils raised to a hightemperature by external application ofheat (super-heated steam) is thensubstituted for the steam. The moistureproduced by the condensation of thesteam is vaporized by the hot air andcarried on gradually to each succeedingplate where it again condenses andvaporizes. In this way the smallquantity of water is carried through theentire press, raising its temperature to80°-100° C. This temperature issubsequently maintained by thepassage of hot air. By this method ofheating the poor conductivity of hot airis overcome through the intermediaryaction of a liquid vapor and the latentheat of steam is utilized to obtain the

initial rise in temperature. To heat asmall press economically whereconditions are such that a large outputis not required the entire press may beencased in a small wooden house whichcan be heated by steam coils. The cakein the press is heated for some timeafter the filtration is complete to assistdrainage. After such treatment the cakeshould contain approximately 15 percent. fat and 25 per cent. water. Thecake is now removed from the pressand transferred to a small tank where itis treated with sufficient caustic sodato convert the fat content into soap.

Saturated brine is then added to salt outthe soap, the Fuller's earth is allowed tosettle to the bottom of the tank and the

soap which solidifies after a short timeis skimmed off to be used in a cheapsoap where color is not important. Theliquor underneath may also be run offwithout disturbing the sediment to beused in graining a similar cheap soap.The waste Fuller's earth contains about0.1 to 0.3 per cent. of fat.

METHOD FOR FURTHERIMPROVEMENT OF

COLOR.

A further improvement of the color ofthe tallow may be obtained by freeingit from a portion of its free fatty acids,either with or without previous Fuller's

earth bleaching.

To carry out this process the melted fatis allowed to settle and as much wateras possible taken off. The temperatureis then raised to 160° F. with dry steamand enough saturated solution of sodaash added to remove 0.5 per cent. ofthe free fatty acids, while agitating themass thoroughly mechanically or byair. The agitation is continued tenminutes, the whole allowed to settle fortwo hours and the foots drawn off. Thesoap thus formed entangles a largeproportion of the impurities of the fat.

VEGETABLE OILS.

Cocoanut Oil, as the name implies, isobtained from the fruit of the cocoanutpalm. This oil is a solid, white fat atordinary temperature, having a blandtaste and a characteristic odor. It israrely adulterated and is very readilysaponified. In recent years the price ofthis oil has increased materiallybecause cocoanut oil is now being usedextensively for edible purposes,especially in the making ofoleomargarine. Present indications arethat shortly very little high grade oilwill be employed for soap manufacturesince the demand for oleomargarine isconstantly increasing and since newmethods of refining the oil for thispurpose are constantly being devised.

The oil is found in the market underthree different grades: (1) Cochincocoanut oil, the choicest oil comesfrom Cochin (Malabar). This product,being more carefully cultivated andrefined than the other grades, is whiter,cleaner and contains a smallerpercentage of free acid. (2) Ceyloncocoanut oil, coming chiefly fromCeylon, is usually of a yellowish tintand more acrid in odor than Cochin oil.(3) Continental cocoanut oil (Copra,Freudenberg) is obtained from thedried kernels, the copra, which areshipped to Europe in large quantities,where the oil is extracted. These driedkernels yield 60 to 70 per cent oil. Thisproduct is generally superior to the

Ceylon oil and may be used as a verysatisfactory substitute for Cochin oil,in soap manufacture, provided it is lowin free acid and of good color. Thewriter has employed it satisfactorily inthe whitest and finest of toilet soapswithout being able to distinguish anydisadvantage to the Cochin oil. Sincecontinental oil is usually cheaper thanCochin oil, it is advisable to use it, asoccasion permits.

Cocoanut oil is used extensively intoilet soap making, usually inconnection with tallow. When usedalone the soap made from this oilforms a lather, which comes up rapidlybut which is fluffy and dries quickly. Apure tallow soap lathers very much

slower but produces a more lastinglather. Thus the advantage of usingcocoanut oil in soap is seen. It isfurther used in making a cocoanut oilsoap by the cold process also for "fake"or filled soaps. The fatty acid contentreadily starts the saponification whichtakes place easily with a strong lye(25°-35° B.). Where large quantities ofthe oil are saponified care must beexercised as the soap formed suddenlyrises or puffs up and may boil over.Cocoanut oil soap takes up largequantities of water, cases having beencited where a 500 per cent. yield hasbeen obtained. This water of coursedries out again upon exposure to theair. The soap is harsh to the skin,

develops rancidity and darkens readily.

Palm Kernel Oil, which is obtainedfrom the kernels of the palm tree ofWest Africa, is used in soap making toreplace cocoanut oil where the lowerprice warrants its use. It resemblescocoanut oil in respect tosaponification and in forming a verysimilar soap. Kernel oil is white incolor, has a pleasant nutty odor whenfresh, but rapidly develops free acid,which runs to a high percentage.

Palm Oil is produced from the fruit ofthe several species of the palm tree onthe western coast of Africa generally,but also in the Philippines. The freshoil has a deep orange yellow tint not

destroyed by saponification, a sweetishtaste and an odor of orris root or violetwhich is also imparted to soap madefrom it. The methods by which thenatives obtain the oil are crude anddepend upon a fermentation, orputrefaction. Large quantities are saidto be wasted because of this fact. Theoil contains impurities in the form offermentable fibre and albuminousmatter, and consequently develops freefatty acid rapidly. Samples tested forfree acid have been found to havehydrolized completely and one seldomobtains an oil with low acid content.Because of this high percentage of freefatty acid, the glycerine yield is small,though the neutral oil should produce

approximately 12 per cent. glycerine.Some writers claim that glycerineexists in the free state in palm oil. Thewriter has washed large quantities ofthe oil and analyzed the wash water forglycerine. The results showed that theamount present did not merit itsrecovery. Most soap makers do notattempt to recover the glycerine fromthis oil, when used alone for soapmanufacture.

There are several grades of palm oil incommerce, but in toilet soap making itis advisable to utilize only Lagos palmoil, which is the best grade. Where it isdesired to maintain the color of thesoap this oil produces, a small quantityof the lower or "brass" grade of palm

oil may be used, as the soap made fromthe better grades of oil graduallybleaches and loses its orange yellowcolor.

Palm oil produces a crumbly soapwhich cannot readily be milled and istermed "short." When used with tallowand cocoanut oil, or 20 to 25 per cent.cocoanut oil, it produces a verysatisfactory toilet soap. In thesaponification of palm oil it is notadvisable to combine it with tallow inthe kettle, as the two do not readilymix.

Since the finished soap has conveyed toit the orange color of the oil, the oil isbleached before saponification.

Oxidation readily destroys the coloringmatter, while heat and light assistmaterially. The methods generallyemployed are by the use of oxygendeveloped by bichromates andhydrochloric acid and the directbleaching through the agency of theoxygen of the air.

CHROME BLEACHINGOF PALM OIL.

The chrome process of bleaching palmoil is more rapid and the oxygen thusderived being more active will bleachoils which air alone cannot. It dependsupon the reaction:

Na2Cr2O7 + 8HCl = Cr2Cl6 + 2NaCl +7O.

in which the oxygen is the activeprinciple. In practice it is foundnecessary to use an excess of acid overthat theoretically indicated.

For the best results an oil should bechosen containing under 2 per cent.impurities and a low percentage of freefatty acids. Lagos oil is best adapted tothese requirements. The oil is meltedby open steam from a jet introducedthrough the bung, the melted oil andcondensed water running to the storetank through two sieves (about 1/8 inchmesh) to remove the fibrous materialand gross impurities. The oil thus

obtained contains fine earthy andfibrous material and vegetablealbuminous matter which should beremoved, as far as possible, sincechemicals are wasted in their oxidationand they retard the bleaching. This isbest done by boiling the oil for onehour with wet steam and 10 per cent.solution of common salt (2 per cent.dry salt on weight of oil used) in alead-lined or wooden tank. Aftersettling over night the brine andimpurities are removed by runningfrom a cock at the bottom of the vatand the oil is run out into the bleachingtank through an oil cock, situated aboutseven inches from the bottom.

The bleaching tank is a lead-lined iron

tank of the approximate dimensions of4 feet deep, 4 feet long and 3-1/2 feetwide, holding about 1-1/2 tons. Thecharge is one ton. A leaden outlet pipeis fixed at the bottom, to which isattached a rubber tube closed by ascrew clip. A plug also is fitted into thelead outlet pipe from above. Seveninches above the lower outlet is affixedanother tap through which the oil isdrawn off.

The tank is further equipped with a wetsteam coil and a coil arranged to allowthorough air agitation, both coils beingof lead. A good arrangement is to useone coil to deliver either air or steam.These coils should extend as nearly aspossible over the entire bottom of the

tank and have a number of smalldownward perforations, so as to spreadthe agitation throughout the mass.

The temperature of the oil is reducedby passing in air to 110° F. and 40pounds of fine common salt per tonadded through a sieve. About one-halfof the acid (40 pounds of concentratedcommercial hydrochloric acid) is nowpoured in and this is followed by thesodium bichromate in concentratedsolution, previously prepared in a smalllead vat or earthen vessel by dissolving17 pounds of bichromate in 45 poundscommercial hydrochloric acid. Thissolution should be added slowly andshould occupy three hours, the wholemass being thoroughly agitated with air

during the addition and for one hourafter the last of the bleaching mixturehas been introduced. The wholemixture is now allowed to settle forone hour and the exhausted chromeliquors are then run off from the lowerpipe to a waste tank. About 40 gallonsof water are now run into the bleachedoil and the temperature raised by opensteam to 150° to 160° F. The mass isthen allowed to settle over night.

One such wash is sufficient to removethe spent chrome liquor completely,provided ample time is allowed forsettling. A number of washings givensuccessively with short periods ofsettling do not remove the chromeliquors effectually. The success of the

operation depends entirely upon thecompleteness of settling.

The wash water is drawn off as beforeand the clear oil run to storage tanks orto the soap kettle through the upper oilcock.

The waste liquors are boiled with wetsteam and the oil skimmed from thesurface, after which the liquors are runout through an oil trap.

By following the above instructionscarefully it is possible to bleach oneton of palm oil with 17 pounds ofbichromate of soda and 85 poundshydrochloric acid.

The spent liquors should be a bright

green color. Should they be of a yellowor brownish shade insufficient acid hasbeen allowed and more must be addedto render the whole of the oxygenavailable.

If low grade oils are being treated morechrome will be necessary, the amountbeing best judged by conducting theoperation as usual and after theaddition of the bichromate, removing asample of the oil, washing the sampleand noting the color of a rapidly cooledsample.

A little practice will enable theoperator to judge the correspondencebetween the color to be removed andthe amount of bleaching mixture to be

added.

To obtain success with this process themethod of working given must beadhered to even in the smallest detail.This applies to the temperature atwhich each operation is carried outparticularly.

AIR BLEACHING OFPALM OIL.

The method of conducting this processis identical with the chrome process tothe point where the hydrochloric acid isto be added to the oil. In this methodno acid or chrome is necessary, as theactive bleaching agent is the oxygen of

the air.

The equipment is similar to that of theformer process, except that a woodentank in which no iron is exposed willsuffice to bleach the oil in. The processdepends in rapidity upon the amount ofair blown through the oil and its evendistribution. Iron should not be presentor exposed to the oil during bleaching,as it retards the process considerably.

After the impurities have beenremoved, as outlined under the chromeprocess, the temperature of the oil israised by open steam to boiling. Thesteam is then shut off and air allowedto blow through the oil until it iscompletely bleached, the temperature

being maintained above 150° F. byoccasionally passing in steam. Usuallya ton of oil is readily and completelybleached after the air has been passedthrough it for 18 to 20 hours, providedthe oil is thoroughly agitated by asufficient flow of air.

If the oil has been allowed to settleover night, it is advisable to run off thecondensed water and impurities by thelower cock before agitating again thesecond day.

When the oil has been bleached to thedesired color, which can be determinedby removing a sample and cooling, themass is allowed to settle, the water runoff to a waste tank from which any oil

carried along may be skimmed off andthe supernatant clear oil run to thestorage or soap kettle.

In bleaching by this process, while theprocess consumes more time and is notas efficient in bleaching the lowergrade oils, the cost of bleaching is lessand with a good oil success is moreprobable, as there is no possibility ofany of the chrome liquors being presentin the oil. These give the bleached oil agreen tint when the chrome method isimproperly conducted and they are notremoved.

Instead of blowing the air through it,the heater oil may be brought intocontact with the air, either by a paddle

wheel arrangement, which, inconstantly turning, brings the oil intocontact with the air, or by pumping theheated oil into an elevated vessel,pierced with numerous fine holes fromwhich the oil continuously flows backinto the vessel from which the oil ispumped. While in these methods air,light and heat act simultaneously in thebleaching of the oil, the equipmentrequired is too cumbersome to bepractical.

Recent investigations[1] in bleachingpalm oil by oxygen have shown thatnot only the coloring matter but the oilitself was affected. In bleaching palmoil for 30 hours with air the free fatty

acid content rose and titer decreasedconsiderably.

Olive Oil, which comes from the fruitof the olive trees, varies greatly inquality, according to the method bywhich it is obtained and according tothe tree bearing the fruit. Threehundred varieties are known in Italyalone. Since the larger portion of oliveoil is used for edible purposes, a lowergrade, denatured oil, denatured becauseof the tariff, is used for soapmanufacture in this country. The oilvaries in color from pale green togolden yellow. The percentage of freeacid in this oil varies greatly, thoughthe oil does not turn rancid easily. It isused mainly in the manufacture of

white castile soap.

Olive oil foots, which is the oilextracted by solvents after the betteroil is expressed, finds its use in soapmaking mostly in textile soaps forwashing and dyeing silks and in theproduction of green castile soaps.

Other oils, as poppy seed oil, sesameoil, cottonseed oil, rape oil, peanut(arachis) oil, are used as adulterants forolive oil, also as substitutes in themanufacture of castile soap, since theyare cheaper than olive oil.

Cottonseed Oil is largely used in themanufacture of floating and laundrysoaps. It may be used for toilet soaps

where a white color is not desired, asyellow spots appear on a finished soapin which it has been used after havingbeen in stock a short time.

Corn Oil and Soya Bean Oil are alsoused to a slight extent in themanufacture of toilet soaps, althoughthe oils form a soap of very little body.Their soaps also spot yellow on aging.

Corn oil finds its greatest use in themanufacture of soap for washingautomobiles. It is further employed forthe manufacture of cheap liquid soaps.

Fatty Acids are also used extensively insoap manufacture. While the soapmanufacturer prefers to use a neutral

oil or fat, since from these the by-product glycerine is obtained,circumstances arise where it is anadvantage to use the free fatty acids.Red oil (oleic acid, elaine) and stearicacid are the two fatty acids mostgenerally bought for soap making. Inplants using the Twitchell process,which consists in splitting the neutralfats and oils into fatty acids andglycerine by dilute sulphuric acid andproducing their final separation by theuse of so-called aromatic sulphonicacids, these fatty acids consisting of amixture of oleic, stearic, palmiticacids, etc., are used directly afterhaving been purified by distillation, theglycerine being obtained from

evaporating the wash water.

Oleic acid (red oil) and stearic acid areobtained usually by the saponificationof oils, fats and greases by acid, limeor water under pressure orTwitchelling. The fatty acids thus arefreed from their combination withglycerine and solidify upon cooling,after which they are separated from thewater and pressed at a higher or lowertemperature. The oleic acid, beingliquid at ordinary temperature, togetherwith some stearic and palmitic acid, isthus pressed out. These latter acids areusually separated by distillation,combined with the press cake furtherpurified and sold as stearic acid.

The red oil, sometimes calledsaponified red oil, is often semi-solid,resembling a soft tallow, due to thepresence of stearic acid. The distilledoils are usually clear, varying in colorfrom light to a deep brown. Stearicacid, which reaches the trade in slabform, varies in quality from a softbrown, greasy, crumbly solid ofunpleasant odor to a snow white, wax-like, hard, odorless mass. The qualityof stearic acid is best judged by themelting point, since the presence ofany oleic acid lowers this. The meltingpoint of the varieties used in soapmanufacture usually ranges from 128°to 132° F. Red oil is used in themanufacture of textile soaps, replacing

olive oil foots soap for this purpose,chlorophyll being used to color thesoap green. Stearic acid, being the hardfirm fatty acid, may be used in smallquantities to give a better grade of soapbody and finish. In adding thissubstance it should always be done inthe crutcher, as it will not mix in thekettle. It finds its largest use for soap,however, in the manufacture of shavingsoaps and shaving creams, since itproduces the non-drying creamy latherso greatly desired for this purpose.Both red oil and stearic acid being fattyacids, readily unite with the alkalicarbonates, carbon dioxide beingformed in the reaction and this methodis extensively used in the formation of

soap from them.

RANCIDITY OF OILSAND FATS.

Rancidity in neutral oils and fats is oneof the problems the soap manufacturerhas to contend with. The mere sayingthat an oil is rancid is no indication ofits being high in free acid. The twoterms rancidity and acidity are usuallyallied. Formerly, the acidity of a fatwas looked upon as the direct measureof its rancidity. This idea is stillprevalent in practice and cannot be toooften stated as incorrect. Fats and oilsmay be acid, or rancid, or acid and

rancid. In an acid fat there has been ahydrolysis of the fat and it hasdeveloped a rather high percentage offree acid. A rancid fat is one in whichhave been developed compounds of anodoriferous nature. An acid and rancidfat is one in which both free acid andorganic compounds of the well knowndisagreeable odors have been produced.

It cannot be definitely stated just howthis rancidity takes place, any morethan just what are the chemicalproducts causing rancidity. The onlyconclusion that one may draw is thatthe fats are first hydrolyzed or split upinto glycerine and free fatty acids. Thisis followed by an oxidation of theproducts thus formed.

Moisture, air, light, enzymes(organized ferments) and bacteria areall given as causes of rancidity.

It seems very probable that the initialsplitting of the fats is caused byenzymes, which are present in theseeds and fruits of the vegetable oilsand tissue of animal fats, in thepresence of moisture. Lewkowitschstrongly emphasizes this point and heis substantiated in his idea by otherauthorities. Others hold that bacteria ormicro-organisms are the cause of thishydrolysis, citing the fact that theyhave isolated various micro-organismsfrom various fats and oils. Theacceptance of the bacterial actionwould explain the various methods of

preservation of oils and fats by the useof antiseptic preparations. It cannot,however, be accepted as a certainty thatbacteria cause the rancidity of fats.

The action of enzymes is a moreprobable explanation.

The hydrolysis of fats and oils isaccelerated when they are allowed toremain for some time in the presenceof organic non-fats. Thus, palm oil,lower grades of olive oil, and tallow,which has been in contact with theanimal tissue for a long time, allcontain other nitrogenous matter andexhibit a larger percentage of free fattyacid than the oils and fats notcontaining such impurities.

Granting this initial splitting of the fatinto free fatty acids and glycerine, thisis not a sufficient explanation. Theproducts thus formed must be actedupon by air and light. It is by the actionof these agents that there is a furtheraction upon the products, and from thisoxidation we ascertain by taste andsmell (chemical means are still unableto define rancidity) whether or not a fatis rancid. While some authorities havepresumed to isolate some of theseproducts causing rancidity, we can onlyassume the presence of the variouspossible compounds produced by theaction of air and light which includeoxy fatty acids, lactones, alcohols,esters, aldehydes and other products.

The soap manufacturer is interested inrancidity to the extent of the effectupon the finished soap. Rancid fatsform darker soaps than fats in theneutral state, and very often carry withthem the disagreeable odor of a rancidoil. Further, a rancid fat or oil isusually high in free acid. It is by nomeans true, however, that rancidity is ameasure for acidity, for as has alreadybeen pointed out, an oil may be rancidand not high in free acid.

The percentage of free fatty acid is ofeven greater importance in the soapindustry. The amount of glycerine yieldis dependent upon the percentage offree fatty acid and is one of thecriterions of a good fat or oil for soap

stock.

PREVENTION OFRANCIDITY.

Since moisture, air, light and enzymes,produced by the presence of organicimpurities, are necessary for therancidity of a fat or oil, the methods ofpreventing rancidity are given.Complete dryness, completepurification of fats and oils and storagewithout access of air or light aredesirable. Simple as these means mayseem, they can only be approximated inpractice. The most difficult problem isthe removal of the last trace of

moisture. Impurities may be lessenedvery often by the use of greater care. Instoring it is well to store in closedbarrels or closed iron tanks away fromlight, as it has been observed that oilsand fats in closed receptacles becomerancid less rapidly than those in openones, even though this method ofstoring is only partially attained.Preservatives are also used, but only inedible products, where theireffectiveness is an open question.

CHEMICAL CONSTANTSOF OILS AND FATS.

Besides the various physical properties

of oils and fats, such as color, specificgravity, melting point, solubility, etc.,they may be distinguished chemicallyby a number of chemical constants.These are the iodine number, the acetylvalue, saponification number, Reichert-Meissl number for volatile acids,Hehner number for insoluble acids.These constants, while they varysomewhat with any particular oil or fat,are more applicable to the edibleproducts and are criterions where anyadulteration of fat or oil is suspected.The methods of carrying out theanalyses of oils and fats to obtain theseconstants are given in the varioustexts[2] on oils and fats, and inasmuchas they are not of great importance to

the soap industry they are merelymentioned here.

OIL HARDENING ORHYDROGENATING.

It is very well known that oils and fatsvary in consistency and hardness,depending upon the glycerides formingsame. Olein, a combination of oleicacid and glycerine, as well as oleic aciditself largely forms the liquid portionof oils and fats. Oleic acid (C18H34O2)is an unsaturated acid and differs fromstearic acid (C18H36O2), the acidforming the hard firm portion of oilsand fats, by containing two atoms of

hydrogen less in the molecule.Theoretically it should be a simplematter to introduce two atoms ofhydrogen into oleic acid or olein, andby this mere addition convert liquidoleic acid and olein into solid stearicacid and stearine.

For years this was attempted and allattempts to apply the well knownmethods of reduction (addition ofhydrogen) in organic chemistry, suchas treatment with tin and acid, sodiumamalgam, etc., were unsuccessful. Inrecent years, however, it has beendiscovered that in the presence of acatalyzer, nickel in finely divided formor the oxides of nickel are usuallyemployed, the process of

hydrogenating an oil is readily attainedupon a practical basis.

The introduction of hardened oils hasopened a new source of raw materialfor the soap manufacturer in that it isnow possible to use oils in soap makingwhich were formerly discarded becauseof their undesirable odors. Thus fish ortrain oils which had up to the time ofoil hydrogenating resisted all attemptsof being permanently deodorized, cannow be employed very satisfactorilyfor soap manufacture. A Japanesechemist, Tsujimoto[3] has shown thatfish oils contain an unsaturated acid ofthe composition C18H28O2, for whichhe proposed the name clupanodonic

acid. By the catalytic hardening of trainoils this acid passes to stearic acid andthe problem of deodorizing these oils issolved.[4]

At first the introduction of hardenedoils for soap manufacture met withnumerous objections, due to thecontinual failures of obtaining asatisfactory product by the use of same.Various attempts have now shown thatthese oils, particularly hardened trainoils, produce extraordinarily usefulmaterials for soap making. Thesereplace expensive tallow and other highmelting oils. It is of course impossibleto employ hardened oils alone, as asoap so hard would thus be obtained

that it would be difficultly soluble inwater and possess very little latheringquality. By the addition of 20-25% oftallow oil or some other oil forming asoft soap a very suitable soap forhousehold use may be obtained.Ribot[5] discusses this matter fully.Hardened oils readily saponify, may beperfumed without any objections anddo not impart any fishy odor to anarticle washed with same.Meyerheim[6] states that through theuse of hydrogenated oils the hardnessof soap is extraordinarily raised, so thatsoap made from hardened cottonseedoil is twelve times as hard as the soapmade from ordinary cottonseed oil.This soap is also said to no longer spot

yellow upon aging, and as aconsequence of its hardness, is able tocontain a considerably higher contentof rosin through which lathering powerand odor may be improved. Hardenedoils can easily be used for toilet soapbases, provided they are not added intoo great a percentage.

The use of hardened oils is not yetgeneral, but there is little doubt that theintroduction of this process goes a longway toward solving the problem ofcheaper soap material for the soapmaking industry.

GREASE.

Grease varies so greatly in compositionand consistency that it can hardly beclassed as a distinctive oil or fat. It isobtained from refuse, bones, hides,etc., and while it contains the sameconstituents as tallow, the olein contentis considerably greater, which causes itto be more liquid in composition.Grease differs in color from an off-white to a dark brown. The betterqualities are employed in themanufacture of laundry and chip soap,while the poorer qualities are only fitfor the cheapest of soaps used inscrubbing floors and such purposes.There is usually found in grease a

considerable amount of gluey matter,lime and water. The percentage of freefatty acid is generally high.

The darker grades of grease arebleached before being used. This isdone by adding a small quantity ofsodium nitrate to the melted grease andagitating, then removing the excesssaltpeter by decomposing withsulphuric acid. A better method ofrefining, however, is by distillation.The chrome bleach is also applicable.

ROSIN (COLOPHONY,YELLOW ROSIN,

RESINA).

Rosin is the residue which remainsafter the distillation of turpentine fromthe various species of pines. The chiefsource of supply is in the States ofGeorgia North and South Carolina. It isa transparent, amber colored hardpulverizable resin. The better gradesare light in color and known as waterwhite (w. w.) and window glass (w. g.).These are obtained from a tree whichhas been tapped for the first year. Asthe same trees are tapped from year toyear, the product becomes deeper anddarker in color until it becomes almostblack.

The constituents of rosin are chiefly(80-90%) abietic acid or its anhydridetogether with pinic and sylvic acids. Its

specific gravity is 1.07-1.08, meltingpoint about 152.5 C., and it is solublein alcohol, ether, benzine, carbondisulfide, oils, alkalis and acetic acid.The main use of rosin, outside of theproduction of varnishes, is in theproduction of laundry soaps, although aslight percentage acts as a binder andfixative for perfumes in toilet soapsand adds to their detergent properties.Since it is mainly composed of acids, itreadily unites with alkaline carbonates,though the saponification is not quitecomplete and the last portion must becompleted through the use of caustichydrates, unless an excess of 10%carbonate over the theoretical amountis used. A lye of 20° B. is best adapted

to the saponification of rosin whencaustic hydrates are employed for thispurpose, since weak lyes causefrothing. While it is sometimesconsidered that rosin is an adulterantfor soap, this is hardly justifiable, as itadds to the cleansing properties ofsoap. Soaps containing rosin are of thewell known yellowish color common toordinary laundry soaps. The price ofrosin has so risen in the last few yearsthat it presents a problem of cost to thesoap manufacturer considering theprice at which laundry soaps are sold.

ROSINSAPONIFICATION.

As has been stated, rosin may besaponified by the use of alkalinecarbonates. On account of thepossibility of the soap frothing over,the kettle in which the operation takesplace should be set flush with the floor,which ought to be constructed ofcement. The kettle itself is an open onewith round bottom, equipped with anopen steam coil and skimmer pipe, andthe open portion is protected by a semi-circular rail. A powerful grid, having a3-inch mesh, covers one-half of thekettle, the sharp edges protrudingupwards.

The staves from the rosin casks areremoved at the edge of the kettle, therosin placed on the grid and beaten

through with a hammer to break it upinto small pieces.

To saponify a ton of rosin there arerequired 200 lbs. soda ash, 1,600 lbs.water and 100 lbs. salt. Half the wateris run into the kettle, boiled, and thenthe soda ash and half the salt added.The rosin is now added through thegrid and the mixture thoroughly boiled.As carbon dioxide is evolved by thereaction the boiling is continued forone hour to remove any excess of thisgas. A portion of the salt is graduallyadded to grain the soap well and tokeep the mass in such condition as tofavor the evolution of gas. Theremainder of the water is added toclose the soap and boiling continued

for one or two hours longer. At thispoint the kettle must be carefullywatched or it will boil over through thefurther escape of carbon dioxide beinghindered. The mass, being in a frothycondition, will rapidly settle bycontrolling the flow of steam. Theremaining salt is then scattered in andthe soap allowed to settle for two hoursor longer. The lyes are then drained offthe top. If the rosin soap is required fortoilet soaps, it is grained a second time.The soap is now boiled with the watercaused by the condensation of thesteam, which changes it to a halfgrained soap suitable for pumping. Asoap thus made contains free soda ash0.15% or less, free rosin about 15%.

The mass is then pumped to the kettlecontaining the soap to which it is to beadded at the proper stage. The timeconsumed in thus saponifying rosin isabout five hours.

NAPHTHENIC ACIDS.

The naphtha or crude petroleum of thevarious provinces in Europe, as Russia,Galacia, Alsace and Roumania yield aseries of bodies of acid character uponrefining which are designated under thegeneral name of naphthenic acids.These acids are retained in solution inthe alkaline lyes during the distillationof the naphtha in the form of alkalinenaphthenates. Upon adding dilute

sulphuric acid to these lyes thenaphthenates are decomposed and thenaphthenic acids float to the surface inan oily layer of characteristicdisagreeable odor and varying fromyellow to brown in color[7]. In Russiaparticularly large quantities of theseacids are employed in the manufactureof soap.

The soaps formed from naphthenicacids have recently beeninvestigated[8] and found to resemblethe soaps made from cocoanut oil andpalm kernel oil, in that they aredifficult to salt out and dissociate veryslightly with water. The latter propertymakes them valuable in textile

industries when a mild soap is requiredas a detergent, e. g., in the silkindustry. These soaps also possess ahigh solvent power for mineral oils andemulsify very readily. The meanmolecular weight of naphthenic acidsthemselves is very near that of the fattyacids contained in cocoanut oil, andlike those of cocoanut oil a portion ofthe separated acids are volatile withsteam. The iodine number indicates asmall content of unsaturated acids.

That naphthenic acids are a valuablesoap material is now recognized, butexcept in Russia the soap is notmanufactured to any extent at thepresent time.

ALKALIS.

The common alkali metals which enterinto the formation of soap are sodiumand potassium. The hydroxides of thesemetals are usually used, except in theso called carbonate saponification offree fatty acids in which case sodiumand potassium carbonate are used. Awater solution of the caustic alkalis isknown as lye, and it is as lyes ofvarious strengths that they are added tooils and fats to form soap. The densityor weight of a lye is considerablygreater than that of water, dependingupon the amount of alkali dissolved,and its weight is usually determined bya hydrometer. This instrument is

graduated by a standardized scale, andwhile all hydrometers should read alikein a liquid of known specific gravity,this is generally not the case, so that itis advisable to check a new hydrometerfor accurate work against one of knownaccuracy. In this country the Bauméscale has been adopted, while inEngland a different graduation knownas the Twaddle scale is used. Thestrength of a lye or any solution isdetermined by the distance theinstrument sinks into the solution, andwe speak of the strength of a solutionas so many degrees Baumé or Twaddlewhich are read to the point where themeniscus of the lye comes on thegraduated scale. Hydrometers are

graduated differently for liquids ofdifferent weights. In the testing of lyesone which is graduated from 0° to 50°B. is usually employed.

Caustic soda is received by theconsumer in iron drums weighingapproximately 700 lbs. each. Thevarious grades are designated as 60, 70,74, 76 and 77%. These percentagesrefer to the percentage of sodium oxide(Na2O) in 100 parts of pure causticsoda formed by the combination of 77-1/2 parts of sodium oxide and 22-1/2parts of water, 77-1/2% beingchemically pure caustic soda. There aregenerally impurities present incommercial caustic soda. These consist

of sodium carbonate, sodium chlorideor common salt and sometimes lime. Itis manufactured by treating sodiumcarbonate in an iron vessel withcalcium hydroxide or slaked lime, orby electrolysis of common salt. Thelatter process has yet been unable tocompete with the former in price.Formerly all the caustic soda used insoap making was imported, and it wasonly through the Americanmanufacturer using a similar containerto that used by foreign manufacturersthat they were able to introduce theirproduct. This prejudice has now beenentirely overcome and most of thecaustic soda used in this country ismanufactured here.

CAUSTIC POTASH.

The output of the salts containingpotassium is controlled almost entirelyby Germany. Formerly the chief sourceof supply of potassium compounds wasfrom the burned ashes of plants, butabout fifty years ago the inexhaustiblesalt mines of Stassfurt, Germany, werediscovered. The salt there minedcontains, besides the chlorides andsulphates of sodium, magnesium,calcium and other salts, considerablequantities of potassium chloride, andthe Stassfurt mines at present arepractically the entire source of allpotassium compounds, in spite of thefact that other localities have been

sought to produce these compounds ona commercial basis, especially by theUnited States government.

After separating the potassium chloridefrom the magnesium chloride and othersubstances found in Stassfurt salts themethods of manufacture of causticpotash are identical to those of causticsoda. In this case, however, domesticelectrolytic caustic potash may bepurchased cheaper than the importedproduct and it gives results equal tothose obtained by the use of theimported article, opinions to thecontrary among soap makers beingmany. Most of the caustic potash in theUnited States is manufactured atNiagara Falls by the Niagara Alkali

Co., and the Hooker ElectrochemicalCo., chlorine being obtained as a by-product. The latter concern employsthe Townsend Cell, for the manufactureof electrolytic potash, and are said tohave a capacity for making 64 tons ofalkali daily.

Since the molecular weight of causticpotash (56) is greater than that ofcaustic soda (40) more potash isrequired to saponify a pound of fat. Theresulting potash soap iscorrespondingly heavier than a sodasoap. When salt is added to apotassium soap double decompositionoccurs, the potassium soap beingtransformed to a sodium soap and thepotassium uniting with the chlorine to

form potassium chloride. This was oneof the earliest methods of making ahard soap, especially in Germany,where potash was derived fromleeching ashes of burned wood andplants.

SODIUM CARBONATE(SODA ASH).

While carbonate of soda is widelydistributed in nature the source ofsupply is entirely dependent upon themanufactured product. Its uses aremany, but it is especially important tothe soap industry in the so calledcarbonate saponification of free fatty

acids, as a constituent of soap powders,in the neutralization of glycerine lyesand as a filler for laundry soaps.

The old French Le Blanc soda process,which consists in treating common saltwith sulphuric acid and reducing thesodium sulphate (salt cake) thusformed with carbon in the form ofcharcoal or coke to sodium sulphide,which when treated with calciumcarbonate yields a mixture of calciumsulphide and sodium carbonate (blackash) from which the carbonate isdissolved by water, has been replacedby the more recent Solvay ammoniasoda process. Even though there is aconsiderable loss of salt and the by-product calcium chloride produced by

this process is only partially used up asa drying agent, and for refrigeratingpurposes, the Le Blanc process cannotcompete with the Solvay process, sothat the time is not far distant when theformer will be considered a chemicalcuriosity. In the Solvay method ofmanufacture sodium chloride (commonsalt) and ammonium bicarbonate aremixed in solution. Doubledecomposition occurs with theformation of ammonium chloride andsodium bicarbonate. The latter salt iscomparatively difficultly soluble inwater and crystallizes out, theammonium chloride remaining insolution. When the sodium bicarbonateis heated it yields sodium carbonate,

carbon dioxide and water; the carbondioxide is passed into ammonia whichis set free from the ammoniumchloride obtained as above bytreatment with lime (calcium oxide)calcium chloride being the by-product.

Sal soda or washing soda is obtained byrecrystallizing a solution of soda ash inwater. Large crystals of sal sodacontaining but 37% sodium carbonateare formed.

POTASSIUMCARBONATE.

Potassium carbonate is not extensivelyused in the manufacture of soap. It may

be used in the forming of soft soaps byuniting it with free fatty acids. Themethods of manufacture are the sameas for sodium carbonate, although amuch larger quantity of potassiumcarbonate than carbonate of soda isobtained from burned plant ashes.Purified potassium carbonate is knownas pearl ash.

ADDITIONAL MATERIALUSED IN SOAP MAKING.

Water is indispensable to the soapmanufacturer. In the soap factory hardwater is often the cause of muchtrouble. Water, which is the best

solvent known, in passing through thecrevices of rocks dissolves some of theconstituents of these, and the water isknown as hard. This hardness is of twok i n d s , temporary and permanent.Temporarily hard water is formed bywater, which contains carbonic acid,dissolving a portion of calciumcarbonate or carbonate of lime. Uponboiling, the carbonic acid is drivenfrom the water and the carbonate, beinginsoluble in carbon dioxide free water,is deposited. This is the cause of boilerscale, and to check this a small amountof sal ammoniac may be added to thewater, which converts the carbonateinto soluble calcium chloride andvolatile ammonium carbonate.

Permanent hardness is caused bycalcium sulphate which is soluble in400 parts of water and cannot beremoved by boiling.

The presence of these salts in waterform insoluble lime soaps which act asinert bodies as far as their value for thecommon use of soap is concerned.Where the percentage of lime in wateris large this should be removed. Amethod generally used is to add about5% of 20° B. sodium silicate to thehard water. This precipitates the limeand the water is then sufficiently pureto use.

Salt, known as sodium chloride, is usedto a large extent in soap making for

"salting out" the soap duringsaponification, as well as grainingsoaps. Soap ordinarily soluble in wateris insoluble in a salt solution, use ofwhich is made by adding salt to thesoap which goes into solution andthrows any soap dissolved in the lyesout of solution. Salt may containmagnesium and calcium chlorides,which of course are undesirable inlarge amounts. The products on themarket, however, are satisfactory, thusno detail is necessary.

Filling materials used are sodiumsilicate, or water glass, talc, silex,pumice, starch, borax, tripoli, etc.

Besides these other materials are used

in the refining of the oils and fats, andglycerine recovery, such as Fuller'searth, bichromates of soda or potash,sulphate of alumina, sulphuric andhydrochloric acids and alcohol.

A lengthy description of thesesubstances is not given, as their modesof use are detailed elsewhere.

FOOTNOTES:

[1] Seifensieder Zeit, 1913, 40, p.687, 724, 740.

[2] Official Methods, see Bull. 107,A. O. A. C., U. S. Dept. Agricult.

[3] Journ. Coll. of Engin. TokyoImper. Univ. (1906), p. 1. Abs.

Chem. Revue f. d. Fett-u. Harz, Ind.16, p. 84; 20, p. 8.

[4] Meyerheim—Fort. der Chem.,Physik. und Physik. Chem. (1913),8. 6, p. 293-307.

[5] Seifs. Ztg. (1913), 40, p. 142.

[6] Loc. cit.

[7] Les Matieres Graisses (1914), 7,69, p. 3367.

[8] Zeit. f. Angew. Chem. (1914),27, 1, p. 2-4.

CHAPTER II

Construction andEquipment of a Soap Plant.

No fixed plan for the construction andequipment of a soap plant can be given.The specifications for a soap factory tobe erected or remodeled must suit theparticular cases. Very often a buildingwhich was constructed for a purposeother than soap manufacture must beadapted for the production of soap. Ineither case it is a question ofengineering and architecture, together

with the knowledge obtained inpractice and the final decision as to thearrangement is best solved by aconference with those skilled in each ofthese branches.

An ideal soap plant is one in which theprocess of soap making, from themelting out of the stock to the packingand shipping of the finished product,moves downward from floor to floor,since by this method it is possible toutilize gravitation rather than pumpingliquid fats and fluid soaps.Convenience and economy are obtainedby such an arrangement.

The various machinery and otherequipment for soap manufacture are

well known to those connected withthis industry. It varies, of course,depending upon the kind of soap to bemanufactured, and full descriptions ofthe necessary machinery are best givenin the catalogs issued by themanufacturers of such equipment, whoin this country are most reliable.

To know just what equipment isnecessary can very easily be describedby a brief outline of the process varioussoaps undergo to produce the finishedarticle. After the saponification hastaken place in the soap kettle themolten soap is run directly into thes o a p frames, which consist of anoblong compartment, holdinganywhere from 400 to 1,200 pounds,

with removable steel sides andmounted upon trucks, in which itsolidifies. In most cases it is advisableto first run the soap into a crutcher ormixer which produces a morehomogeneous mass than if thisoperation is omitted. Color andperfume may also be added at thispoint, although when a better grade ofperfume is added it must beremembered that there is considerableloss due to volatilization of same.When a drying machine is employedthe molten soap is run directly upon therollers of this machine, later addingabout 1.0% zinc oxide to the soap fromwhich it passes continuously throughthe drying chamber and is emitted in

chip form ready for milling. After thesoap has been framed, it is allowed tocool and solidify, which takes severaldays, and then the sides of the frameare stripped off. The large solid cake iscut with wires by hand or by a slabberinto slabs of any desired size. Theseslabs are further divided into smallerdivisions by the cutting table. In non-milled soaps (laundry soaps, floatingsoaps, etc.), these are pressed at thisstage, usually by automatic presses,after a thin hard film has been formedover the cake by allowing it to dryslightly. In making these soaps they arenot touched by hand at any time duringthe operation, the pressing, wrappingand packing all being done by

machinery. For a milled soap the largeslabs are cut into narrow oblong shapesby means of the cutting table to readilypass into the feeder of the chipper, thechips being spread upon trays and driedin a dry house until the moisturecontent is approximately 15%.

The process of milling is accomplishedby passing the dried soap chips througha soap mill, which is a machineconsisting of usually three or fourcontiguous, smooth, granite rollersoperated by a system of gears and setfar enough apart to allow the soap topass from a hopper to the first roller,from which it is constantly conveyed toeach succeeding roller as a thin film,and finally scraped from the last roller

to fall into the milling box in thinribbon form. These mills are oftenoperated in tandem, which necessitatesless handling of soap by the operator.The object of milling is to give thesoap a glossy, smooth finish and toblend it into a homogeneous mass. Theperfume, color, medication or anyother material desired are added to thedried soap chips prior to milling. Somemanufacturers use an amalgamator todistribute these uniformly through thesoap, which eliminates at least onemilling. When a white soap is beingput through the mill, it is advisable toadd from 0.5% to 1% of a good, finequality of zinc oxide to the soap, if thissubstance has not been previously

added. This serves to remove theyellowish cast and any translucencyoccasioned by plodding. Too great aquantity of this compound added, laterexhibits itself by imparting to the soapa dead white appearance. Inasmuch asthe milling process is one upon whichthe appearance of a finished cake oftoilet soap largely depends, it should becarefully done. The number of times asoap should be milled depends uponthe character of a soap being worked. Itshould of course be the object to millwith as high a percentage of moistureas possible. Should the soap becometoo dry it is advisable to add waterdirectly, rather than wet soap, sincewater can more easily be distributed

through the mass. As a generalstatement it may be said it is betterpolicy to overmill a soap, rather thannot mill it often enough.

After the soap has been thoroughlymilled it is ready for plodding. Aplodder is so constructed as to take thesoap ribbons fed into the hopper bymeans of a worm screw andcontinuously force it under greatpressure through a jacketed cylinderthrough which cold water circulates inthe rear to compensate the heatproduced by friction and hot water atthe front, to soften and polish the soapwhich passes out in solid form in barsof any shape and size depending uponthe form of the shaping plate through

which it is emitted. The bars run upon aroller board , are cut into the requiredlength by a special cake cutting table,allowed to dry slightly and pressedeither automatically or by a foot powerpress in any suitable soap die. Thefinished cake is then ready forwrapping and after due time in stockreaches the consumer.

Besides the various apparatusmentioned above there are many otherparts for the full equipment of amodern soap plant, such as remelters,pumps, mixers, special tanks, powerequipment, etc. As has been stated,however, practical experience will aidin judging the practicability as toinstallation of these. The various

methods of powdering soap are,however, not generally known. Where acoarse powder is to be produced, suchas is used for common washingpowders, no great difficulty isexperienced with the well knownBlanchard mill. In grinding soap to animpalpable powder the difficultiesincrease. The methods adapted inpulverizing soaps are by means ofdisintegrators, pebble mills and chasermills. The disintegrator grinds by theprinciple of attrition, that is, thematerial is reduced by the particlesbeing caused to beat against each otherat great velocity; a pebble mill crushesthe substance by rubbing it betweenhard pebbles in a slowly revolving

cylinder; the chaser mill first grindsthe material and then floats it as a veryfine powder above a curb of fixedheight. The last method is particularlyadapted for the finest of powder (140mesh and over).

CHAPTER III

Classification of Soap-Making Methods.

In the saponification of fats and oils toform soap through the agency ofcaustic alkalis, as has been stated, thesodium or potassium salts of the mixedfatty acids are formed. Sodium soapsare usually termed hard soaps, andpotassium soaps soft. There are,however, a great many varieties ofsoaps the appearance and properties ofwhich depend upon their method of

manufacture and the oils or fats usedtherein.

The various methods adopted in soapmaking may be thus classified:

1. Boiling the fats and oils in openkettles by open steam with indefinitequantities of caustic alkali solutionsuntil the finished soap is obtained;ordinarily named full boiled soaps.These may be sub-divided into (a) hardsoaps with sodium hydrate as a base, inwhich the glycerine is recovered fromthe spent lyes; (b) hard soaps with sodaas a base, in which the glycerineremains in the soap, e. g., marinecocoanut oil soaps; (c) soft potashsoaps, in which the glycerine is

retained by the soap.

2. Combining the required amount oflye for complete saponification of a fattherewith, heating slightly with dryheat and then allowing thesaponification to complete itself. Thisis known as the cold process.

3. Utilizing the fatty acid, instead ofthe neutral fat, and combining itdirectly with caustic alkali orcarbonate, which is incorrectly termedcarbonate saponification, since it ismerely neutralizing the free fatty acidand thus is not a saponification in thetrue sense of the word. No glycerine isdirectly obtained by this method, as itis usually previously removed in the

clearage of the fat by either theTwitchell or autoclave saponificationmethod.

In the methods thus outlined the onemost generally employed is the fullboiled process to form a sodium soap.This method of making soap requiresclose attention and a knowledge whichcan only be obtained by constantpractice. The stock, strength of lyes,heat, amount of salt or brine added,time of settling, etc., are all influencingfactors.

The principles involved in this processare briefly these:

The fat is partly saponified with weak

lyes (usually those obtained from aprevious boiling in the strengtheningchange are used), and salt is added tograin the soap. The mass is thenallowed to settle into two layers. Theupper layer is partly saponified fat; thelower layer, or spent lye, is a solutionof salt, glycerine, and contains anyalbuminous matter or any otherimpurity contained in the fat. This isknown as the killing or glycerinechange. Strong lyes are now added andthe fat entirely saponified, which istermed the strengthening change. Themass is then allowed to settle and thefluid soap run off above the "nigre."This operation is called the finish orfinishing change.

The method may be more fullyillustrated by a concrete example of themethod of manufacture of a tallowbase:

Charge—Tallow 88 per cent.Cocoanut oil 10 per cent.Rosin w. w. 2 per cent.Amount charge 10 tons

About five tons of tallow and one tonof cocoanut oil are pumped or run intothe soap kettle and brought to a boilwith wet steam until it briskly comesthrough the hot fat. The caustic soda(strengthening lyes from formerboilings may be used here) is gradually

added by the distributing pipe, anytendency to thicken being checked bythe introduction of small quantities ofbrine ("salt pickle"). If the lye is addedtoo rapidly the soap assumes a granularappearance, indicating that the additionof same must be discontinued. Watershould then be added and the massboiled through until it again closes.When the addition of the properamount of caustic soda is nearing itscompletion the soap gradually thins.The steam is now cut down to aboutone turn of the valve, and brine israpidly added or salt shoveled in. In tento fifteen minutes the steam againbreaks through and, from theappearance of the soap, it can be seen

whether sufficient brine has beenadded. A sample taken out by means ofa long wooden paddle should show thesoap in fine grains with the lyesrunning from it clear. The steam is thenshut off and the soap allowed to settlefrom one and one-half to two hours. Inall settlings the longer time thisoperation is permitted to continue, thebetter will the subsequent operationsproceed.

The mixture now consists of a partlysaponified layer of fat above the spentlyes. The lyes are drawn off until soapmakes its appearance at the exit pipe.The valve is then closed and the soapblown back into the kettle by steam.The lyes thus obtained are known as

spent lyes, from which the glycerine isrecovered. They should show analkalinity of approximately 0.5 percent. if the operation is carefullycarried out.

The remaining tallow is now added andthe above operations repeated.

After the spent lyes have been drawnoff, the soap is closed with water andthe proper percentage of rosin soappreviously formed, or rosin itself isadded to the mass in the kettle. Morelye is then allowed to flow in until themixture is up to "strength." This isusually tested by the "bite" on thetongue of a small cooled sample. Afterboiling until the steam comes through,

the mass is grained with salt as beforeand allowed to settle one and one-halfto three hours. These lyes, known asstrengthening lyes are run to storage tobe used subsequently with fresh fat totake up the caustic soda containedtherein.

The soap is now ready for finishing andis first boiled through and tried forstrength. A drop of phenolphthalein (1per cent. phenolphthalein in 98 percent. alcohol) is allowed to drop on themolten soap taken up on a trowel. Thered color should be instantly producedand develop to a full deep crimson in afew seconds, or more lye must beadded until this condition is realized.Should it flash a deep crimson

immediately it is on the strong side.This cannot be conveniently remedied;it can only serve as a guide for the nextboil, but in any case it is not of anyserious consequence, unless it is toostrong.

With the steam on, the soap is nowexamined with a trowel which must bethoroughly heated by working it aboutunder the surface of the hot soap. Theappearance of the soap as it runs fromthe face of the trowel indicates itscondition. It is not possible toabsolutely describe the effect, whichcan only be properly judged bypractice, yet the following points mayserve as a guide. The indications to benoticed are the shape and size of the

flakes of soap as the sample on thetrowel breaks up and runs from the hotiron surface, when the latter is turnedin a vertical position, as well as thecondition of the iron surface fromwhich the soap flakes have fallen. Aclosed soap will run slowly into ahomogeneous sheet, leaving thetrowel's surface covered with a thinlayer of transparent soap; a grainedmass will run rapidly down in tinygrains, about one-half an inch indiameter or less, leaving the hot trowelabsolutely dry. The object of the finishis to separate the soaps of the lowerfatty acids from those of the higher,and both from excess of liquid. A pointmidway between "open" and "closed" is

required to arrive at this point.

Having arrived at the above condition,the soap is allowed to settle anywherefrom one to three days and then run offthrough the skimmer pipes to the nigreand framed or pumped to the tankfeeding the drying machine.

The stock thus obtained should befairly white, depending upon the gradeof tallow used and slightly alkaline toan alcoholic phenolphthalein solution.If removed at exactly the neutral pointor with a content of free fat the soapwill sooner or later develop rancidity.The soap thus obtained is an ordinarytallow base, and the one by far greatestused in the manufacture of toilet soaps.

The percentage of cocoanut oilindicated is not fixed and may readilybe varied, while in fine toilet soap therosin is usually eliminated.

In the manufacture of full boiled sodasoaps in which no glycerine is obtainedas a by-product, it being retained in thesoap itself, the soap formed is knownas a "run" soap. The process is usedmost extensively in the manufacture ofmarine soaps by which the method maybe best illustrated. This soap is knownas marine soap because of its propertyof readily forming a lather with saltwater and is mostly consumed aboardvessels.

Marine soaps are manufactured by first

placing in the kettle a calculatedamount of lye of 25 deg. to 35 deg. B.,depending upon the amount ofmoisture desired in the finished soaps,plus a slight excess required tosaponify a known weight of cocoanutoil. With open steam on, the cocoanutoil is then gradually added, care beingtaken that the soap does not froth over.Saponification takes place readily andwhen the oil is entirely saponified thefinished soap is put through the processknown as running. This consists inconstantly pumping the mass from theskimmer pipe back into the top of thekettle, the object being to prevent anysettling of the nigre or lye from thesoap, as well as producing a

homogeneous mass. It is customary tobegin the saponification in themorning, which should be completedby noon. The soap is then run for aboutthree hours and framed the nextmorning. After having remained in theframe the time required to solidify andcool, the soap is slabbed and cut intocakes. This process is difficult to carryout properly, and one not greatlyemployed, although large quantities ofmarine soap are purchased by thegovernment for use in the navy andmust fulfill certain specificationsrequired by the purchasing department.

In making potash soaps it is practicallyimpossible to obtain any glycerinedirectly because of the pasty

consistency of the soap, and nograining is possible because theaddition of salt to a soft soap, asalready explained, would form a sodasoap. Large quantities of soft soaps arerequired for the textile industries whodesire mostly a strong potash soap, andthe large number of automobiles in useat the present time has opened a fieldfor the use of a soft soap for washingthese. A soap for this purpose must beneutral so as not to affect the varnish orpaint of automobiles.

A suitable soap for textile purposesmay be made as follows:

Red oil 80 partsHouse grease 20 parts

Caustic soda lye, 36 degs.B. 3 parts

Carbonate of potash 5-1/2 parts

Caustic potash 23-1/4 parts

Olive oil, corn oil, soya bean oil, oliveoil foots or cottonseed oil may replaceany of the above oils. A large quantityof cottonseed oil will cause the soap tofig.

To carry out the process, the causticpotash and carbonate of potash aredissolved and placed in the kettletogether with the soda lye, and the oilsadded. This is most satisfactorilyaccomplished by being finished the day

before the boiling is begun. The nextday the boiling is begun and wateradded to bring the soap up to thedesired percentage of fatty acid, dueallowance being made for the waterformed by the condensation of the opensteam in boiling. Care must be takenthat the soap in the kettle does notswell and run over during thesaponification. A good procedure is touse open steam for a period of abouttwo hours, then close the valve andallow the saponification to continuewithout boiling, and repeat this until itis entirely saponified. After thesaponification has been completed thesoap is briskly boiled all day and theproper corrections made; that is, if too

alkaline, more oil is added, and if freefat is present, more potash. About 2 percent. carbonate of potash is the properamount for a soap containing 50 percent. fatty acid. The soap is sampled byallowing it to drop on a clean, coldglass surface. In so doing, the soapshould not slide or slip over the glasssurface when pressed thereon, butshould adhere to the glass, or it is tooalkaline. A sample worked between thefingers showing too much stringinessshould have more strong potash and oiladded. A sample taken out in a pail andallowed to cool over night will serve asa guide as to the body of the soap in thekettle. When the soap has thus beenproperly finished it is run into barrels.

For an automobile soap the followingis a good working formula:

Corn oil 1,000 partsPotash lye, 31-1/2 degs. B. 697 parts

Proceed as in the directions just givenfor textile soap in placing charge in thekettle. When the kettle is boiling upwell, shut off the steam and thesaponification will complete itself. Thesoap may be run into the barrels thenext day.

A heavy soap with a smaller percentageof fat may be made as follows:

Corn oil 1,000 parts900 parts

Potash lye, 24-1/2 degs. B.

Boil until the soap bunches, and shovelthe finished soap into barrels. Uponstanding it will clear up. By theaddition of more water the yield ofsoap per pound of oil may be run up to300 per cent.

After soft soaps have been allowed tostand for some time the phenomenonknown as "figging" often occurs. Thisterm is applied to a crystalline-likeformation, causing spots of a star-likeshape throughout the soap. This isundoubtedly due to the stearine contentof the soap crystallizing out as it cools,and forming these peculiarly-shaped

spots. It more generally occurs in thewinter and may be produced artificiallyby adding a small quantity of soda tothe potash lye before saponification.

The oils usually employed in themanufacture of potash soaps arecottonseed oil, corn oil, soya bean oil,olive oil foots, red oil, cocoanut oil,grease and the various train oils. Theusual percentage yield is from 225 percent. to 300 per cent., based upon theweight of oil used. In calculating theweight of a soft soap it is to beremembered that since potassium has ahigher molecular weight (56) thansodium (40), the corresponding soapformed is that much greater in weightwhen compared with a sodium soap.

Rosin may be added to soft soaps as acheapening agent.

COLD PROCESS.

The cold process for manufacturingsoap is the simplest method of soapmaking, and the equipment required issmall when compared to the othermethods. All the more expensiveequipment that is necessary is acrutcher, a tank to hold the lye, frames,a slabber or cutting table, and a press.Yet, in spite of the simplicity of thusmaking soap, the disadvantages arenumerous for the production of a goodpiece of soap. The greatest difficulty isto obtain a thorough combination of oil

or fat and lye so that there will not bean excess of one or the other in thefinished soap. At its best there is eithera considerable excess of free fat whichlater exhibits itself in producingrancidity or uncombined caustic, whichproduces an unpleasant effect on theskin when the soap is consumed forwashing. The latter objection, ofcourse, can only be applied to toiletsoaps.

Cocoanut oil is used very largely in themanufacture of cold-made soaps as it iswell adapted for this purpose, althoughit is by no means true that other oilsmay not be employed. Since by thisprocess of manufacture no impuritycontained in the fat or oil is removed in

the making of the soap, it is necessarythat in order to obtain a fine finishedproduct, any impurity contained inthese may be removed if present, orthat the fats be as pure as can beobtained. If inedible tallow is used forcold-made soap, it is advisable tobleach it by the Fuller's Earth Process.

The carrying out of this method is bestillustrated by an example of a cold-made cocoanut oil soap.

Charge:Cochin cocoanut oil 846 partsLye (soda), 35 degs. B. 470 partsWater 24 parts

The oil is run into the crutcher and thetemperature of the oil raised to 100degs. F. by dry steam. The lye andwater are at room temperature. Afterall the oil is in the crutcher, the lye andwater are slowly added to prevent anygraining of the soap. Toward the endthe lye may be added more rapidly.When all the lye is in, the mass iscrutched for about three hours, or untilupon stopping the crutcher a fingerdrawn over the surface of the soapleaves an impression. If this conditionis not realized, the soap must be mixeduntil such is the case. Having arrived atthis point, the mixture is dropped into aframe which should remain uncovered.The heat produced by the further

spontaneous saponification will causethe soap to rise in the middle of theframe. After having set for some daysit is ready to be slabbed and cut intocakes.

A potash soap may be made by the coldprocess just as readily as a soda soap.Soaps of this type may be made byeither of these formulae in a crutcher:

Olive oil foots 600Potash lye, 18 degs. B. hot, 20degs. B. cold 660

or

Corn oil 800Rosin 200

Potash lye, 27 degs. B. 790Water 340

Heat the oils to 190 degs. F., add thelye and crutch until the soap begins tobunch, when it is ready to be run intobarrels where the saponification will becompleted.

Semi-boiled soaps differ from thosemade by the cold process intemperature. In making semi-boiledsoaps the fats are usually heated to140° F. The addition of the lye raisesthe temperature to 180°—200° F. whensaponification takes place.

CARBONATE

SAPONIFICATION.

The method of the formation of soapby the utilization of the fatty aciddirectly, from which the glycerine hasalready been removed by some methodof saponification other than withcaustic soda, and neutralizing this withalkali, is becoming increasinglypopular. The glycerine is more easilyrecovered from a previous cleavage ofthe fats or oils, but a soap made fromthe mixed fatty acids thus obtained isseldom white in color and retains anunpleasant odor. Since soda ash orsodium carbonate is cheaper thancaustic soda and readily unites with afatty acid, it is used as the alkali in the

carbonate saponification. The processis similar to that already given underRosin Saponification. About 19 percent. by weight of the fatty acidsemployed of 58 per cent. soda ash isdissolved in water until it has a densityof 30 degs. B., and the solution is runinto the kettle, which is usuallyequipped with a removable agitator.The fatty acids, previously melted, arethen slowly added while the mixture isboiled with open steam and agitatedwith the stirring device. The fatty acidsinstantly unite with the carbonate andrise in the kettle, due to the generationof carbon dioxide, and care must beexercised to prevent boiling over. Afterall the fatty acid has been added, and

the mass is boiled through thesaponification must be completed withcaustic soda, as there is as yet nopractical method known which willsplit a fat entirely into fatty acid andglycerine. Thus about 10 per cent. ofthe fatty acids are true neutral fats andrequire caustic soda for theirsaponification. This is then added andthe soap completed, as in full-boiledsoaps.

In carrying out this method upon alarge scale, largesue\Neanderthal\doroteer\Neanderthal\Josephine\quantities of carbon dioxide are formedduring the boiling of the soap, whichreplaces a quantity of the air containedtherein. The kettle room should

therefore be well ventilated, allowingfor a large inflow of fresh air from outof doors.

CHAPTER IV

Classification of Soaps.

In considering the many differentvarieties of soaps, their classification ispurely an arbitrary one. No definiteplan can be outlined for any particularbrand to be manufactured nor can anyvery sharp distinction be drawnbetween the many soaps of differentproperties which are designated byvarious names. It is really a question towhat use a soap is to be put, and atwhat price it may be sold. There is, of

course, a difference in the appearance,form and color, and then there aresoaps of special kinds, such as floatingsoaps, transparent soaps, liquid soaps,etc., yet in the ultimate sense they areclosely allied, because they are all thesame chemical compound, varyingonly in their being a potash or sodasoap, and in the fatty acids which enterinto combination with these alkalis.Thus we can take a combination oftallow and cocoanut oil and make agreat many presumably different soapsby combining these substances withcaustic soda, by different methods ofmanufacture and by incorporatingvarious other ingredients, as air, toform a floating soap, alcohol to make a

transparent soap, dyestuffs to give adifferent color, etc., but essentially it isthe same definite compound.

The manufacturer can best judge thebrand of soaps he desires tomanufacture, and much of his successdepends upon the name, package,shape, color or perfume of a cake ofsoap. It is the consumer whom he mustplease and many of the large sellingbrands upon the market today owe theirsuccess to the above mentioned details.The great majority of consumers ofsoap know very little concerning soap,except the fact that it washes or has apleasant odor or looks pretty, and themanufacturer of soap must study thesephases of the subject even more

carefully than the making of the soapitself.

For a matter of convenience we willclassify soap under three generaldivisions:

I. Laundry soaps, including chip soaps,soap powders and scouring soaps.

II. Toilet soaps, including floatingsoap, castile soap, liquid soap, shavingsoap, etc.

III. Textile soaps.

LAUNDRY SOAP.

The most popular household soap is

laundry soap. A tremendous amount ofthis soap is consumed each day in thiscountry, and it is by far manufacturedin larger quantities than any other soap.It is also a soap which must be soldcheaper than any other soap that entersthe home.

The consumers of laundry soap havebeen educated to use a full boiledsettled rosin soap and to make a goodarticle at a price this method should becarried out, as it is the one mostadvisable to use. The composition ofthe fats entering into the soap dependsupon the market price of these, and it isnot advisable to keep to one formula inthe manufacture of laundry soap, butrather to adjust the various fatty

ingredients to obtain the desired resultswith the cheapest material that can bepurchased. It is impossible to use agood grade of fats and make a profitupon laundry soap at the price at whichit must be retailed. The manufacturerof this grade of soap must look to theby-product, glycerine, for his profit andhe is fortunate indeed if he realizes theentire benefit of this and still producesa superior piece of laundry soap.

SEMI-BOILED LAUNDRYSOAPS.

It is advantageous at times to make alaundry soap by a method other than

the full boiled settled soap procedureas previously outlined. This isespecially the condition in making anaphtha soap, in which is incorporatednaphtha, which is very volatile andsome of the well known manufacturersof this class of soap have adopted thisprocess entirely. A laundry soapcontaining rosin cannot beadvantageously made by the coldprocess, as the soap thus made grainsduring saponification and drops aportion of the lye and filling materials.By making a semi-boiled soap thisobjection is overcome. The half boiledprocess differs from the cold processby uniting the fats and alkalis at ahigher temperature.

To carry out this process the followingformulae have been found byexperience to give satisfactory results.

I. lbs.Tallow 100Rosin 60Soda Lye, 36° B. 80II.Tallow 100Rosin 60Silicate of Soda 25Soda Lye, 36° B. 85III.Tallow 100Rosin 100Lye, 36° B. 105Silicate of Soda 25Sal Soda Solution 20

In any of these formulas the sodiumsilicate (40° B.) may be increased tothe same proportion as the fats used.By so doing, however, twenty poundsof 36° B. lye must be added for everyhundred pounds of silicate additional tothat indicated or in other words, forevery pound of silicate added 20 percent. by weight of 36° B. lye must beput into the mixture. The rosin mayalso be replaced by a previously maderosin soap.

To make a semi-boiled soap, using anyof the above formulae, first melt therosin with all or part of the fat, as rosinwhen melted alone readilydecomposes. When the mixture is at150° F. run it into the crutcher and add

the lye. Turn on sufficient dry steam tokeep the temperature of the soap atabout 150° F. in the winter or 130° F.in summer. After the mass has beenmixed for half an hour, by continuouslycrutching the soap it will at firstthicken, then grain and it may againbecome thick before it becomessmooth. When the mass is perfectlysmooth and homogeneous drop into aframe and crutch in the frame by handto prevent streaking. After standing therequired length of time the soap isfinished into cakes as usual.

SETTLED ROSIN SOAP.

Settled rosin soaps are made from

tallow, grease, cottonseed oil, bleachedpalm oils of the lower grades, corn oil,soya bean oil, arachis oil, distilledgarbage grease, cottonseed foots orfatty acids together with an addition ofrosin, varying from 24 per cent. to 60per cent. of the fatty acids whichshould titer from 28 to 35. A titer lowerthan 28 will prevent the finished kettleof soap from being capable of latertaking up the filling materials. As hasalready been stated under hardenedoils, these being very much higher intiter allow a greater percentage of rosinto be added. Thus hardened fish oilsand cottonseed oil are gradually beingmore extensively employed in soaps ofthis character.

The procedure of handling the kettle issimilar to that given under full boiledsoap. The stock is steamed out into asettling tank and allowed to settle overnight, after which it is pumped into thesoap kettle. Having stocked the kettle,open steam is turned on and 10°-12° B.lye is run in, while using a steampressure of ninety to one hundredpounds in order to prevent too great aquantity of condensation of the steam,the water thus being formed weakeningthe lye. If a steam pressure of fifty tosixty pounds is available, a stronger lye(20° B.) should be added. Care must betaken not to allow the lye to flow in toorapidly or the soap will not grain. Thesaponification is only attained by

prolonged boiling with sufficient lye ofproper strength. When saponificationhas taken place, the mass begins toclear and a sample taken out with apaddle and cooled should show a slightpink with a 1 per cent. alcoholicphenolphthalein solution.

It may be stated here that in using thisindicator or any other to test thealkalinity of soap, the soap shouldalways be cooled and firm, aswhenever water is present, thedissociation of the soap thereby willalways react alkaline. When this stateis reached the mass is ready forgraining, which is accomplished bydistributing salt brine or pickle orspreading dry salt over the surface of

the soap. The kettle is then thoroughlyboiled until the mass shows a soft curdand the lye drops clearly from a sampletaken out with a trowel or paddle. Thesteam is then shut off and the soapallowed to settle over night. The lyesare then run off to the spent lye tankfor glycerine recovery. In saponifying afreshly stocked kettle it is apt to bunch.To prevent this salt is added at varioustimes to approximately one per cent. ofthe fat used.

If, by any possibility the soap hasbunched, this condition may beremedied by the addition of morestrong lye and boiling until it is takenup. To work a kettle to its full capacityit is advisable to make two "killing"

changes. First add about 75 per cent. ofthe fat and grain as directed. Run offthe spent lyes and then add theremainder of the stock and repeat theprocess. When the spent lye has beenrun to storage, the open steam is againturned on and 18° B. lye graduallyallowed to run in. The rosin is nowbroken up and put into the kettle, or apreviously made rosin soap is pumpedin.

Lye is then added until the soap has asharp taste after about three hours ofcontinuous boiling, or when the soap isin the closed state. More lye shouldthen be run into the kettle to grain thesoap well, the grain not being toosmall. Then allow the soap to settle

over night and draw off thestrengthening lye. The next day againboil up the kettle and add water untilthe soap thins out and rises or swellshigh in the kettle. A sample taken outat this stage upon a hot trowel shouldrun off in large flakes. The surface ofthe soap should be bright and shiny.

If the sample clings to the trowel, aslight addition of lye will remedy thisdefect. The kettle is then allowed torest, to drop the nigre and to cool forsome time, depending upon the size ofthe kettle. The proper temperature issuch that after having been pumped tothe crutcher and the filling materialshaving been added, a thermometerplaced into the mass should indicate

128°-135° F. after the crutcher has runfrom ten to fifteen minutes. The fillingmaterial may consist of from 7-9 percent. of sal soda solution, 36°-37° B.warm or just enough to close up thesoap and make it rise high in the centerof a screw crutcher and make it clingclose to a warm trowel. Other fillerssuch as outlined below are added at thispoint.

An addition of from 2-3 per cent. of aspecial mineral oil for this purpose willimpart a finish to the soap and 3-5 percent. starch added prevents the soapfrom cracking in the frames. Otherfilling material as silicate of soda,borax, talc or silex are used. After thefilling material has been thoroughly

crutched through the soap it is framed,and, after being several days in theframe to solidify and cool the soap isready for slabbing, pressing andwrapping.

In order to more definitely illustratethe composition of the mixture of fatsand oils entering into the formation ofa laundry soap a typical formula maybe given for such a soap containing 40per cent. rosin added to the amount offats used:

lbs.Grease 7,000Tallow 4,000Corn Oil 7,000

Cottonseed Oil 3,000Rosin 8,400

The following have been found to besatisfactory filling materials and arecalculated upon the basis of a 1,400-pound frame of soap.

I. lbs.Sodium Silicate, 38°-40° B. 100Mineral Oil 25Sal Soda Solution, 36° B. 80Borax 1II.Sal Soda Solution, 36° B. 80Mineral Oil 25Sodium Silicate 60

III.Soda Ash 10Sal Soda 55Sodium Silicate 115Mineral Oil 40Brine (Saturated Solution) 10Sodium Silicate, 38°-40° B. 100IV.Sodium Silicate 100Silex or Talc 200Soda Ash 50V.Sal Soda Solution, 36° B. 90Sodium Silicate 50-60Mineral Oil 25Borax Solution, 25° B. (hot) 15

CHIP SOAP.

Chip soap is used extensively inlaundries but is also used largely inother branches. It may be made eitheras a settled soap or by the cold madeprocess.

To make a full boiled settled chip soap,proceed as directed under settledlaundry soap. The kettle is stocked withlight grease or a mixture of grease withcorn oil or other cheap oils. For thiskind of soap the rosin is eliminated.

Chip soap may be filled as well aslaundry soap. This is done in the

crutcher and the followingadulterations are suitable.

lbs.Settled Soap 700Soda Ash 35Sodium Silicate 215orSettled Soap 700Silicate of Soda 560Soda Ash 18Carbonate of Potash, 26° B. 50

The cheapest method of drying is byrunning this soap through a dryingmachine and this is the procedureusually carried out for making dried

chip soap.

COLD MADE CHIPSOAPS.

To make chip soaps by the cold processa sweet tallow of low percentage offree fatty acid should be employed. Thetallow is heated to 120° to 135° F. andthe lye run in slowly at first and thenthe silicate of soda is added. The massis then mixed until a finger drawnthrough the soap leaves a slightimpression, then dropped into framesor barrels. Soaps containing a smallpercentage of fat should be wellcovered in the frame for twenty-four

hours to retain their heat and insureproper saponification. The followingformulae are suitable:

I. lbs.Tallow 1,200Soda Lye, 35° B. 850Sodium Silicate 750II.Tallow 475Ceylon Cocoanut Oil 100Soda Lye, 37° B. 325Potash Lye, 37° B. 56III.Tallow 500Soda Lye, 37-1/2° B. 297

Sodium Silicate 416Potash Lye, 37-1/2° B. 37-1/2IV.Tallow 450Soda Lye, 37-1/2° B. 255Sodium Silicate 450Potash Lye, 37-1/2° B. 50V.Tallow 450Soda Lye, 35° B. 470Sodium Silicate 650VI.Tallow 420Sodium Silicate 600Soda Lye, 37-12° B. 270

UNFILLED CHIP SOAP.

A very good grade of chip soap is madeby employing no filling materialwhatsoever, but unfortunately the priceof this soap has been cut to such anextent that these can not compete witha filled chip. A number of the bestsoaps of this kind are made from asettled soap using a light grease withcorn oil. A soap of this nature is madeas follows.

lbs.Settled Soap 800Sal Soda Solution, 36°-37° B. 252Soda Ash 182

If this soap is run into frames it may bestripped and chipped in two days.

SOAP POWDERS.

Soap powders have become so great aconvenience as a general cleansingagent that to eliminate them from thehousehold necessities would meanmuch unnecessary energy and work tothe great number of consumers of thisproduct. They may be manufactured socheaply and still be efficient, that theiruse has almost become universal forcleansing and scouring purposes. Theuses to which soap and scouringpowders are adapted are too wellknown to enter into a description of

their employment. Since they offer agreater profit to the manufacturer thanordinary household soap, many brandsare extensively advertised.

Numerous combinations for soappowders might be cited and it is asimple matter to vary the ingredients asto fat content and manufacture apowder of this sort as low as a cent apound. Many substances areincorporated with soap, such as salt,soda ash, tripoli, crushed volcanicdeposits, ground feldspar, infusorialearth of various kinds, silex, etc. Inaddition to these various fillers,compounds with true cleansing andbleaching properties, in addition tosoap, are added, such as the salts of

ammonium (sal ammoniac, carbonateof ammonia), sodium perborate and theperoxides of various metals. Thepublic, however, have been accustomedto receive a large package of soap orscouring powder for a small amount ofmoney and it is a difficult matter forthe manufacturer to add moreexpensive substances of this nature tohis product, to increase its efficiency,without raising the price or decreasingthe size of the package.

In manufacturing soap powders, thedried soap chips might be mixed withthe filler and alkali and thenpulverized. This method is notextensively employed nevertheless.The process which is the most

economical is one whereby theingredients are mixed in a speciallyadapted mixer for heavy material untildry and then run directly to the crusherand pulverizer, after which it isautomatically packed, sealed andboxed. Another method of procedure isto run out the mixture from thecrutcher to the frames, which arestripped before the soap cools, and iscut up at once, for if it hardens it couldnot be cut with wires. It is better,however, to run the mixture into sheetsupon a specially constructed floor andbreak up the mass when cool.

Formulae for soap powders which havebeen found to be suitable for runningdry in the mixer follow:

ISoda ash, 58 per cent. 42 lbs.Silica 220 "Settled soap (usuallycottonseed). 25 "

Salt 10 "IISoap (settled cottonseed) 40 lbs.Soda ash, 58 per cent. 60 "IIISettled soap 100 lbs.Soda ash, 58 per cent. 400 "

Fillers in varying proportions mayreplace the soda ash in the aboveformulae. It is of course understoodthat the soap has been previously made

and run as molten soap into thecrutcher.

The following soap powders will notdry up in the crutcher upon running,but are of the class which may beframed or run on the floor to solidify:

ISoap 850 lbs.Filler 400 "Sal soda solution, 20 degs. B 170 "IISoap 650 lbs.Filler 550 "Sal soda solution, 20 degs. B. 340 "III

Soap 80 lbs.Filler 550 "Sal soda solution 170 "IVSoap (settled tallow) 800 lbs.Filler 400 "Sal soda solution 170 "Water 100 "

V

First saponify 100 parts house greaseand 100 parts ordinary grease and makea run soap. Then use in crutcher either:

Soap 400 lbs.Filler 575 "

Hot water 60 "orSoap 200 lbs.Hot water 200 "Filler 625 "

It would be a simple matter to writenumerous additional formulae, but theabove are typical. The manufacturermust judge for himself just what fillingmaterial to use. The filler indicated inthe above formulae is therefore leftopen. A few formulae for moreexpensive powders than those givenrecently appeared among others in the"Seifensieder Zeitung"[9]:

I

Powdered soap 90 lbs.Sodium perborate 10 "

The perborate should be added whenthe powder is perfectly dry or it losesits bleaching properties.

IISoap powder, 20 per cent. fat.Cocoanut oil fatty acids 25 lbs.Olein 25 "Bone fat 70 "Soda lye, 30 degs. B. 90 "Water 150 "Ammonium carbonate 125 "IIISoap powder, 10 per cent. fat.

Cocoanut oil fatty acids 20 lbs.Olein 10 "Bone fat 20 "Soda lye, 30 degs. B. 30 "Water 175 "Ammonium carbonate 175 "

LIGHT OR FLUFFYPOWDERS.

Light or fluffy powders containing 35-45% moisture can be made in twoways. The first method requiring aminimum equipment is to mix thepowder and sal soda in a mixer, allowit to stand in frames for a week to

crystallize or spread it on the floor fora few hours to dry and then grinding it.

The continuous method finishes thepowder in a few minutes and with aminimum amount of labor. By thisprocess the various ingredients, soap,soda ash solution, etc., are measured,run by gravity into the mixer, mixedand the molten mass run over thecrystallizer or chilling rolls thru whicheither cold water or brine is pumped.From the roll the powder is scraped offclean by a knife, passes to a screenwhich sends the tailings to a grinder,falls into a storage bin from whence itis weighed and packed by an automaticweighing machine into cartons madeup in most cases by another machine.

Due to the large percentage of moisturecontained in these soap powders thecarton is generally wrapped in waxpaper to aid in the prevention of theescape of moisture.

SCOURING POWDERS.

Scouring powders are very similar tosoap powders and differ only in thefiller used. We have already consideredthese fillers under scouring soap, fromwhich they do not differ materially.They are usually insoluble in water toaid in scouring. The mixer used forsubstances of this kind in incorporatingthe soap and alkali must be of strongconstruction.

SCOURING SOAP.

Scouring soaps resemble soap powdersvery closely in their composition, inthat they are a combination of soap andfilling material. Since more lather isrequired from a scouring soap than insoap powders, a cocoanut oil soap isgenerally used. The usual fillingmaterial used is silex. The greatestdifficulty in the manufacture ofscouring soap is the cracking of thefinished cake. This is usually due to theincorporation of too great an amount offiller, or too high a percentage ofmoisture.

In manufacturing these soaps the

cocoanut oil is saponified in thecrutcher with 38 degs. B. lye, orpreviously saponified as a run soap, asalready described under "MarineSoaps." To twenty-five parts of soapare added a percentage of 38 degs. B.sal soda or soda ash solution, togetherwith a small quantity of salt brine. Tothis mixture in the crutcher seventy-five parts of silex are then added, and asufficient amount of hot water to makethe mass flow readily. Care must beexercised to not add too great aquantity of water or the mass will crackwhen it cools. The mass is then framedand cut before it sets, or poured intomolds and allowed to set. While silexis the most extensively used filler for

scouring soaps, it is feasible toincorporate other substances of likecharacter, although it is to beremembered that the consumer isaccustomed to a white cake, such assilex produces. Any other material usedto replace silex should also be as fineas this product.

FLOATING SOAP.

Floating soap occupies a positionmidway between laundry and toiletsoap. Since it is not highly perfumedand a large piece of soap may bepurchased for small cost, as is the casewith laundry soap, it is readilyadaptable to general household use.

Floating soap differs from ordinarysoap in having air crutched into itwhich causes the soap to float in water.This is often advantageous, especiallyas a bath soap, and undoubtedly thelargest selling brand of soap on theAmerican market today is a floatingsoap.

In the manufacture of floating soap ahigh proportion of cocoanut oil isnecessary. A most suitable compositionis one part cocoanut oil to one part oftallow. This is an expensive stock forthe highest grade of soap and is usuallycheapened by the use of cottonseed orvarious other liquid oils. Thus it ispossible to obtain a floating soap froma kettle stocked with 30 per cent.

cocoanut oil, 15 per cent. cottonseedoil and 55 per cent. tallow. With thisquality of soap, however, there is apossibility of sweating and rancidity,and of the soap being too soft andbeing poor in color.

The process of manufacture is to boilthe soap in an ordinary soap kettle,after which air is worked into the hotsoap by a specially constructedcrutcher, after which the soap isframed, slabbed, cut into cakes andpressed.

Concerning the boiling of the soap, thesaponification must be carefullycarried out, as the high proportion ofcocoanut oil may cause a violent

reaction in the kettle causing it to boilover.

The method of procedure is the same asfor a settled soap up to the finishing.When the mass is finally settled afterthe finish, the soap should be more onthe "open" side, and the object shouldbe to get as long a piece of goods aspossible.

Due to its high melting point, a muchharder crust forms on the surface of afloating soap and in a greaterproportion than on a settled soapduring the settling. In a large kettle, infact, it has been found impossible tobreak through this crust by the ordinaryprocedure to admit the skimmer pipe.

Much of the success of the subsequentoperations depends upon thecompleteness of the settling, and inorder to overcome the difficultiesoccasioned by the formation of thecrust everything possible should bedone in the way of covering the kettlecompletely to enable this period ofsettling to continue as long as possible.

When the soap is finished it is run intoa specially constructed U-shapecrutcher, a Strunz crutcher is bestadapted to this purpose, although arapidly revolving upright screwcrutcher has been found to givesatisfaction upon a smaller scale, and asufficient quantity of air beaten intothe soap to make it light enough to

float. Care must be taken not to run thecrutcher too rapidly or the soap will beentirely too fobby. During thisoperation the mass of soap increases inbulk, and after it has been establishedhow much air must be put into the soapto satisfy the requirements, thisincrease in bulk is a criterion toestimate when this process iscompleted.

It is of course understood that thelonger the crutching continues thegreater quantity of air is incorporatedand the increase of volume must beestablished for a particularcomposition by sampling, cooling thesample rapidly and seeing if it floats inwater. If the beating is continued too

long an interval of time, the finishedsoap is too spongy and useless.

The temperature of the mass duringcrutching is most important. This mustnever exceed 158 degrees F. At 159degrees F. the operation is not verysuccessful, yet the thermometer mayindicate 140 degrees F. withoutinterfering with this operation. If,however, the temperature drops toolow, trouble is liable to be met with, bythe soap solidifying too quickly in theframes.

When the crutching is completed, thesoap is allowed to drop into framesthrough the valve at the bottom of thecrutcher and rapidly crutched by the

hand in the frames to prevent large airspaces and then allowed to cool. It is animprovement to jolt the frames as theyare drawn away as this tends to makethe larger air bubbles float to thesurface and thus reduce the quantity ofwaste. When the soap has cooled, theframe is stripped and the soap slabbedas usual. At this point a layer ofconsiderable depth of spongy soap willbe found to have formed. This ofcourse must be cut away and returnedto the kettle. The last few slabs are alsooften rejected, inasmuch as the weightof the soap above them has forced outso much of the air that the soap nolonger floats. As a fair average it maybe estimated that not more than 50 to

60 per cent. of the soap in the kettlewill come out as finished cakes. theremaining 40 to 50 per cent. beingconstituted by the heavy crust in thekettle, the spongy tops, the bottomslabs and scrapings. This soap is ofcourse reboiled and consequently notlost, but the actual cakes obtained areproduced at a cost of practically doublelabor.

It is advisable to add a small quantityof soap blue color to the mass whilecrutching to neutralize the yellowishtint a floating soap is liable to have.

Some manufacturers add a percentageof carbonate of soda, about 3 per cent.,to prevent the soap from shrinking.

Floating soap may also be loaded withsodium silicate to the extent of about 5per cent.

TOILET SOAP.

It is not a simple matter to differentiatebetween toilet soaps and various othersoaps, because numerous soaps areadaptable to toilet purposes. Whilesome soaps of this variety aremanufactured by the cold made orsemi-boiled process, and not milled,the consumer has become accustomedto a milled soap for general toilet use.

The toilet base most extensivelyemployed is a tallow and cocoanut base

made as a full boiled settled soap. Themanufacture of this base has alreadybeen outlined and really needs nofurther comment except that it is to beremembered that a suitable toilet soapshould contain no great excess of freealkali which is injurious to the skin.Cochin cocoanut oil is preferable to theCeylon cocoanut oil or palm kernel oil,to use in conjunction with the tallow,which should be a good grade and colorif a white piece of goods is desired.The percentage of cocoanut oil may beanywhere from 10 to 25 per cent.,depending upon the kind of latherrequired, it being remembered thatcocoanut oil increases the latheringpower of the soap.

In addition to a tallow base, numerousother oils are used in the manufactureof toilet soaps, especially palm oil,palm kernel oil, olive oil and olive oilfoots, and to a much less extent arachisor peanut oil, sesame oil and poppyseed oil, oils of the class of cottonseed,corn and soya bean oils are not adaptedto manufacturing a milled soap, as theyform yellow spots in a finished cake ofsoap which has been kept a short time.

Palm oil, especially the Lagos oil, ismuch used in making a palm base. Ashas already been stated, the oil isbleached before saponification. A palmbase has a yellowish color, a sweetishodor, and a small quantity added to atallow base naturally aids the perfume.

It is especially good for a violet soap.The peculiarity of a palm oil base isthat this oil makes a short soap. By theaddition of some tallow or twenty totwenty-five per cent. of cocoanut oil, orboth, this objection is overcome. It is agood plan in using a straight palm baseto add a proportion of yellow color tohold the yellowish tint of this soap, as asoap made from this oil continuesbleaching upon exposure to air andlight.

Olive oil and olive oil foots are usedmost extensively in the manufacture ofcastile soaps. The peculiarity of anolive oil soap is that it makes a veryslimy lather, and like palm oil givesthe soap a characteristic odor. An olive

oil soap is usually considered to be avery neutral soap and may readily besuperfatted. Much olive oil soap isused in bars or slabs as an unmilledsoap and it is often made by the coldprocess. Peanut oil or sesame andpoppy seed oil often replaces olive oil,as they form a similar soap to olive oil.

In the manufacture of a toilet soap it ishardly practical to lay down a definiteplan for the various bases to be made.From the combination of tallow, palmoil, cocoanut oil, palm kernel oil, oliveoil and olive oil foots, a great manybases of different proportions might begiven. The simplest method is to makea tallow base, a palm base and an oliveoil base. Then from these it is an easy

matter to weigh out any proportion ofthese soap bases and obtain the propermixture in the mill. If, however, as isoften the case, a large quantity of soapbase of certain proportions of these,four or even more of these fats and oilsis required, it is not only moreeconomical to stock the kettle with thecorrect proportion of these oils, but amore thorough mixture is thus obtainedby saponifying these in the kettle. Inview of the fact that it is really aquestion for the manufacturer to decidefor himself what combination of oils hedesires for a particular soap we willsimply outline a few typical toilet soapbases in their simplest combination. Itis understood that these soaps are

suitable for milled soaps and are to bemade as fully boiled settled soaps.Palm kernel oil may be substituted forcocoanut oil in all cases.

TALLOW BASE.

Tallow 75-90 partsCocoanut oil 25-10 parts

PALM BASE.

Bleached Lagos palm oil 75-80 partsCocoanut oil 25-20 parts

or

Tallow 30 partsPalm oil 60 partsCocoanut oil 10 parts

OLIVE OIL BASE (WHITE).

Olive oil 75-90 partsCocoanut oil 25-10 parts

or

Olive oil 40 partsTallow 40 partsCocoanut 20 parts

Where a green olive oil base is desired,olive oil foots are substituted for the

olive oil. Peanut oil may replace theolive oil or part of it, the same beingtrue of sesame oil and poppy seed oil.

PALM AND OLIVE BASE.

Palm oil 50 partsOlive oil 30 partsCocoanut oil 20 parts

or

Palm oil 20 partsOlive oil 10 partsTallow 50 partsCocoanut oil 20 parts

CHEAPER TOILETSOAPS.

It is often necessary to manufacture acheaper grade of soap for toiletpurposes to meet the demand of acertain class of trade as well as forexport. To accomplish this it is ofcourse necessary to produce a veryinferior product and run down thepercentage of fatty acids contained inthe soaps by the addition of fillers or touse cheaper oils in manufacturing. Themost simple method of filling a soap isto load it at the mill with somesubstance much less expensive than thesoap itself. Many of the cheaper toilet

soaps, however, are not milled and it is,therefore, necessary to follow out someother procedure.

Milled soaps, as has just been stated,are loaded at the mill. The consumersof cheaper toilet soaps in this countryare accustomed to a milled soap andthis grade of soap for homeconsumption is very often filled withnumerous substances, but mostgenerally by adding starch and talc.The addition of such materials ofcourse later exhibit themselves byimparting to the cake of soap a deadappearance. Talc is more readilydetected in the soap than starch bywashing with it, as talc is insoluble andimparts a roughness to the soap, like

sand or pumice, as the soap wearsdown. It may readily be added to 20 percent. by weight. Starch is to bepreferred to talc, in loading a soap, as itis not so readily noticeable in washing.It leaves the cake itself absolutelysmooth although the lather formed ismore shiny. This substance may beemployed to as high a percentage asone-third the weight of the soap. It is,of course, possible to cheapen the bestsoap base by this method and the pricemay be further lowered by using theless expensive oils and fats to make thesoap base.

RUN AND GLUED UP

SOAPS.

A very cheap grade of soap may bemade by making a run soap and addingthe filler e. g. sodium silicate in thekettle during saponification. Thepercentage of fatty acids may bebrought down to 10 per cent., althoughof course a soap of this type shrinks awhole lot upon exposure.

In making a "glued up" soap theprocedure is the same for making thesoap itself as with a settled soap,except that the soap is finished "curd"and later filled in the crutcher. Thepercentage of fatty acids in a soap ofthis type is seldom below 50 per cent.

The method of "gluing up" a soap isbest illustrated by a typical soap of thischaracter in which the kettle is chargedwith the following stock.

Bleached palm oil 5 partsDistilled grease 2 "Cotton oil foots stock, 63%fatty acid 1 "

Rosin 4 "

The palm oil is first run into the kettle,saponified and washed to extract anyglycerine, then the rest of the fats andfinally the rosin. The soap is thenfinished and settled as with a boiledsettled soap. To assure success it isabsolutely necessary that the soap

settle as long a period as possible, oruntil the temperature is about 150 degs.F. The ideal temperature for carryingout the "gluing up" process is 140 degs.F., as at a lower temperature than thisthe soap is liable to cool too quicklyand not be thoroughly glued up. Ahigher temperature than 150 degs. F.causes delay in that the soap does notproperly take the filler at a highertemperature and the soap must be keptin the crutcher until the temperaturedrops to the right point.

The soap is run into the crutcher andthe percentage of fatty acids run downto 50-55 per cent. with one of thefollowing mixtures:

Sodium silicate, 59-1/2° B. 1 partPotassium carbonate, 51° B. 1 "

or

Sodium silicate, 59-1/2° B. 1 partPotassium carbonate, 51° B. 1 "Sodium sulfate, 28° B. 1 "

From 230 to 300 pounds of either ofthese mixtures are required for acrutcher holding 2,600 pounds of soap.

The crutching is continued until themass is well "spiked," that is to say, afreshly broken surface of the soap, asthe crutcher blade is jerked away,stands up like shattered sheets intriangular form (Δ Δ Δ), which retain

their shape perfectly. When thiscondition is realized the soap is runinto frames which are carefullycrutched by hand to remove any airspaces. The surface of the soap is thensmoothed down and heaped up in thecenter. After standing a day to contract,the surface is again leveled and asnugly-fitting board placed on the topof the soap upon which a weight isplaced or upon which the workmantreads and stamps until the surface isflat, thus assuring the further removalof air spaces. The soap remains in theframe from six to eight days and isthen slabbed, barred and pressed by theusual method employed for soaps thushandled without milling.

In a soap of this nature no hard and fastrule can be laid down as to the quantityof solution to be used for "gluing up"or the strength of the solution. In asoap of the type described the mostsatisfactory appearing cake will beobtained from a soap containing 58 percent. fatty acids. That is to say, about 8per cent. to 10 per cent. filling solutionis added per hundred pounds of soap.The filling solutions given are verysatisfactory. Carbonate of soda shouldbe avoided in connection with sodiumsilicate as the property of efflorescingon the surface of the finished cake aftera short time will prove detrimental. Toassure successful gluing up it isadvisable to experiment upon a small

scale to determine the exact extent towhich the filling solution should bediluted. Various proportions of waterare added to a certain quantity of thefilled soap. After the soap has beenfilled in a small receptacle a sample istaken and rubbed between the fingers.If the freshly exposed surface issmooth and glossy, the filling solutionis weak enough, if rough it is toostrong. It is of course understood thatthe temperature must be correct, 140degs. to 150 degs. F., or the soap willbe rough. By this means the operatorcan readily judge the correct strengthof his filling solution. When properlycarried out a perfectly satisfactory soapis obtained.

CURD SOAP.

The object of a soap which is finished"curd" or grained, is to obtain a harderpiece of goods from low titer fat or toincrease the percentage of fatty acids inthe finished soap. This is still anothermethod of producing a cheap grade ofsoap as by its adoption the cheaper oilsand fats may be used to obtain a firmpiece of soap.

A typical charge for curd soap is:

Red oil 63 partsTallow 10 "Rosin 27 "

Cotton seed foots may be employed inplace of red oil and a tallow of too hightiter is not suitable for this kind ofsoap.

The red oil and tallow are firstsaponified with 15 degs. B. lye, boilerpressure 80-90 pounds, 18 degs. B. lyefor lower steam pressure, and twowashings given to extract the glycerine.The rosin is added at the strengtheningchange and at the finish the soap is"pitched," that is to say, the soap issettled over night only. The next day

the lyes are drawn off and a portion ofthe nigre pumped to another kettlewhich prevents later streaking of thesoap. The soap is then boiled with 18degs. B. lye as with anotherstrengthening change under closedsteam. Salt brine or "pickle," 15 degs.B. is then added and the mass boiledwith closed steam until the brinereaches a density of 18 degs. B. and thekettle pumped the next day. A soap ofthis type requires either hand or powercrutching to assure homogeneity andprevention of streaks. To obviate anyair spaces it is advisable to place overthe top of the frame a tightly-fittedboard which is heavily weighted down.This soap is also pressed without any

milling.

COLD MADE TOILETSOAPS.

Comparatively little toilet soap is madeby the cold or semi-boiled processes.While these are the simplest methodsof manufacturing soaps the drawbacksof using them are numerous and only ina few cases are they very extensivelyemployed. To make a toilet soap by thecold process a combination of goodgrade tallow and cocoanut oil isrequired. It requires 50 per cent. byweight of 36 degs. B. lye to saponify agiven weight of tallow and 50 per cent.

of 38 degs. B. lye for cocoanut oil. Thelyes are used full strength or may bereduced slightly with water and themethod of procedure is the same asalready given in the general directionsfor cold made soaps.

Cold made soaps are readily filled withsodium silicate which is added at thesame time the stock is put into thecrutcher. In adding the silicate it isnecessary to add additional lye to thatrequired for saponifying the fats, about20 per cent. of 36 degs. B. lye is theproper amount. There is of course acertain amount of shrinking due to theaddition of this filler and the finishedcake is exceedingly hard, yet the authorhas seen a good looking cake of cheap

soap made from as high a proportion as420 parts of tallow to 600 parts ofsilicate.

Cold made soaps are usually pressedwithout milling, although it is readilyfeasible to mill a cold made soapprovided it is not a filled soap such ashas just been described.

PERFUMING ANDCOLORING TOILET

SOAPS.

Equally important as the soap itself oreven to a greater extent is the perfumeof a toilet soap. A prominent

manufacturer recently made thestatement, which is often the truth, thatit makes no difference to the publicwhat kind of soap you give them, aslong as you put plenty of odor into it.The perfuming of soaps is an art initself and a subject to be treated by oneversed in this particular branch. Wecan only take into account theimportance of the perfume as related totoilet soap not only, but the necessityof adding a certain proportion of thecheaper products of odoriferous natureto laundry soap to cover and disguisethe odor of even this type of soap.

The price of a cake of toilet soap to agreat extent depends upon the perfume,and the manufacturer should aim to

give the best possible perfume for acertain price. He should not allow hispersonal likes or dislikes to enter intothe judgment of whether an odor isgood or not, but submit it to a numberof persons to obtain the concensus ofopinion. In giving or selling a piece ofsoap to the consumer, it is secondnature for him to smell it, and in thegreat majority of cases his opinion isformed not from any quality the soapitself may have during use, but fromthe odor. This only emphasizes the factthat the perfume must be pleasing, notto one person, but to the majority, andmany brands owe their popularity tonothing more than the enticingperfume.

Perfuming of soap is closely allied tothe soap making industry, but as stateda branch in itself. It is, therefore, notour purpose to give numerous formulaeof how to perfume a soap, but rather toadvise to go for information to someone who thoroughly understands thecharacteristics of the numerousessential oils and synthetics and givepositive information for the particularodor desired. Under no circumstancesis it advisable to purchase a perfumealready compounded, but since allperfumes are a blend of several ormany essential oils and synthetics, it isa more positive assurance of obtainingwhat is desired, by purchasing thestraight oils and blending or mixing

them as one desires.

The perfume is added to a milled soapjust before the milling process in theproper proportion per hundred poundsof soap. In cold made or unmilledsoaps it is added in the crutcher whilethe soap is still hot. By this method, ofcourse, a proportion of the perfume islost due to its being more or lessvolatile.

COLORING SOAP.

While much toilet soap is white ornatural in color, many soaps are alsoartificially colored. The soap colorsused for this purpose are mostly aniline

dyestuffs. The price of these dyestuffsis no criterion as to their quality, as theprice is usually regulated by theaddition of some inert, water solublesubstance like common salt or sugar.

The main properties that a dyestuffsuitable for producing a colored soapshould have are fastness to light and toalkali. They should further be of such atype that the color does not come offand stain a wash cloth or the handswhen the soap is used and should besoluble in water. Under nocircumstances is it advisable to addthese in such a quantity that the latherproduced in the soap is colored. It iscustomary to first dissolve the dye inhot water as a standardized solution.

This can then be measured out in agraduate and added to the soap thesame time as the perfume is put in.About one part of color to fifty parts ofwater is the proper proportion to obtaina perfect solution, though this is by nomeans fixed. In making up a solutionthus it is an improvement to add to thesame about one-half of one per cent. ofan alkali either as the hydroxide orcarbonate. Then, if there is anypossibility of change of color due toalkalinity of the soap, it will exhibititself before the color is added.

A particularly difficult shade to obtainis a purple, as there is up to the presenttime no purplish aniline color knownwhich is fast to light. Very good results

in soap may be obtained by mixing afast blue, as ultramarine or cobalt blue,with a red as rhodamine or eosine.

Inasmuch as the colors for soap havebeen carefully tested by most of thedyestuff manufacturers, and theirinformation, usually reliable, is open toany one desiring to know about a colorfor soap, it is better to depend upontheir experience with colors afterhaving satisfied one's self that a coloris what it is represented for a particularshade, than to experiment with thenumerous colors one's self.

MEDICINAL SOAPS.

Soap is often used for the conveyanceof various medicants, antiseptics orother material presumably beneficialfor treatment of skin diseases. Whilesoap is an ideal medium for thecarrying of such materials, it is anunfortunate condition that whenincorporated with the soap, all but avery few of the numerous substancesthus employed lose their medicinalproperties and effectiveness for curingskin disorders, as well as any antisepticvalue the substance may have. Soap isof such a nature chemically that manyof the substances used for skin troublesare either entirely decomposed oraltered to such an extent so as to impairtheir therapeutic value. Thus many of

the claims made for various medicatedsoaps fall flat, and really have no moreantiseptic or therapeutic merit thanordinary soap which in itself hascertain germicidal and cleaning value.

In medicating a soap the material usedfor this purpose is usually added at themill. A tallow and cocoanut oil base isbest adapted for a soap of this type.The public have been educated more orless to the use of colored soap toaccentuate its medicinal value, andgreen is undoubtedly the most popularshade. This inference, however, is byno means true for all soaps of thischaracter. Possibly the best method ofarranging these soaps is briefly tooutline some medicinal soaps.

SULPHUR SOAPS.

The best known sulphur soaps containanywhere from one to 20 per cent. offlowers of sulphur. Other soaps containeither organic or inorganic sulphurcompounds.

TAR SOAP.

The tar used in the manufacturing oftar soap is obtained by the destructivedistillation of wood, the pine tar beingthe most extensively employed. Whilethe different wood tars containnumerous aromatic compounds, suchas phenols, phenyl oxides, terpenes and

organic acids, these are present in sucha slight proportion so as to render theireffectiveness practically useless. It has,therefore, been tried to use thesevarious compounds contained in the tarthemselves to make tar soap reallyeffective, yet tar is so cheap asubstance that it is usually thesubstance used for medicating a tarsoap. About 10 per cent. of tar isusually added to the soap with 2 ouncesof lamp black per hundred pounds ofsoap.

SOAPS CONTAININGPHENOLS.

Phenol (Carbolic Acid) is mostextensively used in soaps of this kind,which are called carbolic soaps.Carbolic soaps are generally coloredgreen and contain from 1 to 5 per cent.phenol crystals.

The cresols are also extensively usedfor making soaps named carbolic.These substances impart more odor tothe soap and really have moredisinfecting powers than phenol whenincorporated with soap.

Other soaps, containing the phenolgroup, which are well known areresorcinol soap, salol soap, thymolsoap, naphthol soap, etc. From one tofive per cent of the compound after

which the soap is named is usuallyincorporated with the soap.

PEROXIDE SOAP.

Hydrogen peroxide in itself is anexcellent disinfectant. It loses all itsmedicinal value, however, when addedto the soap. To overcome this objectionvarious metallic peroxides are added tothe soap, as sodium peroxide, zincperoxide and barium peroxide. Thesegenerate hydrogen peroxide by theaddition of water. Sodium perborate isalso used in peroxide soaps, as thissubstance is decomposed by water intohydrogen peroxide and sodiummetaborate.

MERCURY SOAPS.

Mercuric chloride (corrosivesublimate) is most extensively used forthe production of mercury soaps.Because of its extremely poisonousproperties care should be taken in usingit. Since it really eventually loses anyantiseptic value in the soap throughforming an insoluble mercury soap itmight better be omitted entirely.

LESS IMPORTANTMEDICINAL SOAPS.

While the above mentioned soaps areprobably the best known medicated

soaps, there are numerous other soapswhich may be classed under thesekinds of soaps. Thus we have coldcream soap, which can be made byadding Russian Mineral Oil, 1 to 5 percent., to the soap; witch hazel soap,made by the addition of extract ofwitch hazel; iodine soap, made byadding iodine or iodoform;formaldehyde soap, made by addingformaldehyde; tannin soaps, made byadding tannin. In fact, there have beenincorporated in soap so great a numberof substances that the list might begreatly enlarged.

Medicated soaps are not only used insolid form, but in powder, paste andliquid soap as well. The only difference

in a soap like those just referred to isthat the medicant is incorporated withthese forms of soaps as conveniencedirects.

CASTILE SOAP.

A pure castile soap should be madefrom olive oil. This, however, is notalways the case, as a number of oils aswell as tallow are used to adulteratethis oil to cheapen it, and there areeven some soaps called castile whichcontain no olive oil at all. Most of thepure castile soap used in this country isimported, as it is a difficult matter forthe American manufacturer to competewith the pure imported castile soap,

since both labor and oil itself are somuch cheaper in the vicinities ofEurope where this oil is produced, thatthis advantage is more thancompensated by the carrying andcustom charges by importing thecastile soap.

Castile soap may be made either by thefull boiled or cold process. There arenumerous grades of olive oil, and thoseused for soap making are denatured tolower the duty charges. Olive oil makesa hard white soap, usually sold in bars,and olive oil foots a green soap, due tothe coloring matter contained in thisoil.

To make a boiled castile soap, a

composition of 10 per cent. Cochincocoanut oil and 90 per cent. olive oilmay be used. To cheapen this, peanutoil (Arachis oil) may entirely replacethe olive oil, or about 20 per cent. ofcorn or soya bean oil may be added.The oils are saponified as usual inmaking a settled soap and to preventrancidity the soap is boiled near thefinish for some time in the closed statewith sufficient excess of alkali to giveit a sharp taste, then grained with lye,the lye drawn off, closed with waterand then grained with salt. This processis repeated until the desired strength isreached. The last graining should notbe too great, and on the last change thesoap should not be thinned out, as it

will contain too great a quantity ofwater when slabbed.

In making a cold castile soap the usualmethod is pursued as already directedunder cold made soap. When the soapis taken from the crutcher it isadvisable, however, to keep the soap inthe frame well covered to assurecomplete saponification. Somemanufacturers use very small frameswhich are placed into compartments,well insulated to retain heat. Severalformulae for cold made castile soaps,follow. It may be noted that some ofthese contain practically no olive oil.

IOlive oil 2030

Palm kernel 674Soda lye, 35 per cent. B. 1506IIOlive oil 2030Cochin cocoanut oil 674Soda lye, 36 per cent. B. 1523Sodium Silicate 82IIIPalm kernel oil 1578Tallow 940Olive oil 7Sodium silicate, 20 per cent. 190Soda lye, 36 per cent. B. 1507IVOlive oil (yellow) 1000

Soda lye, 37 per cent. B. 500VOlive oil 90orPalm kernel } 10Cochin or cocoanut oil } 10Lye, 37 per cent. B. 51

If any of the soaps containing a highproportion of cocoanut oil are boiledthe soap will float. It is thereforenecessary to keep the temperature aslow as possible.

ESCHWEGER SOAP(BLUE MOTTLED).

Eschweger soap is a colored mottled ormarbled soap made to a very slightextent in this country. Inasmuch as ithas been introduced to the export trade,it is made for this purpose by somemanufacturers. A high percentage ofcocoanut oil is usually used togetherwith tallow and grease. About one-thirdof each is a typical formula. In a soapof this character the fact that cocoanutoil soap takes up a large quantity ofwater and salts of various kinds and isdifficult to salt out is made use of. Thetallow and grease are first saponified asusual, then the cocoanut oil is pumpedand saponified. When thesaponification is nearly completedeither silicate or carbonate of soda or

common salt are added to make thesoap "short" so as to form the mottle.The finishing of a soap of this type canonly be gained by practice and it israther difficult to explain the exactappearance of the kettle at this stage.The surface of the soap should bebright and lustrous with the steamescaping in numerous places in rose-like formation. A sample on the trowelshould have a slight sharpness to thetongue and be plastic. When the soapslides from the trowel it should breakshort. When the soap has reached thisstage the desired coloring matter,usually ultramarine, is added to thesoap either in the kettle or crutcher andthe soap framed. The yield is 200-215

pounds per hundred pounds of stock.

Several modifications of this generalmethod for Eschweger soap are used byadopting the half boiled or coldprocess.

TRANSPARENT SOAP.

Transparent soap is really not a mostdesirable soap for toilet purposes, as itcontains an excess of free alkali. It has,nevertheless, met with public approvalbecause of the fact it is novel in beingtransparent. Except for this fact verylittle merit can be claimed for a soap ofthis kind.

The transparency of soap is generally

due to the presence of alcohol, sugar orglycerine in the soap when it is made.It is very essential in a soap of thischaracter, where lightness andclearness of color are desired, that thematerial for making the soap becarefully selected as to color andpurity. The perfumes also play animportant part in the color of the soapand many of the tinctures, balsams andinfusions used in perfuming soap mayeventually cause trouble by spotting. Ifthe soap is artificially colored, which isalmost always the case, the dyestuffsused for this purpose should havecareful attention and only those shouldbe used which are known to resist theaction of alkalis. Where rosin is used

this product must be of the bettergrade. Distilled water is alwayspreferable for use in transparent soap.The government permits the use of aspecially denatured alcohol. Thisalcohol is not taxed and consists ofgrain (ethyl) alcohol denatured with 5per cent. wood (methyl) alcohol. Somesoapmakers prefer to use a moreexpensive refined methyl alcohol, butoutside of adding to the cost of thesoap, there is no particular advantage.The glycerine should be chemicallypure. As to the oils and fats theseshould be low in acid and of goodcolor. Under no circumstances shouldthe crutcher or kettle in which the soapis made be rusty or unclean in any way.

For a light soap enameled utensils areto be preferred.

To obtain transparency in soap thefollowing general methods may begiven.

1. Where the transparency is due tosugar.

2. Where alcohol and glycerineproduce transparency.

3. Where (1) or (2) is supplemented bythe use of castor oil.

4. Where transparency depends uponthe percentage of fatty acid in a soapand the number of times the soap ismilled.

Under the first method at least 25 percent. of the charge should be cocoanutoil, the other constituent being tallowor any fat or oil capable of giving asufficiently hard soap. The soap isboiled and finished as usual, then runto the crutcher to be mixed with astrong cane sugar solution, containing10-20 per cent. sugar of the weight ofthe soap. The sugar is dissolved in itsown weight of water and the solutionheated to 175 degs. F. before beingvery slowly added to the soap. As thewater evaporates, soaps of this typeshow spots due to the sugar thus beingthrown out of solution.

Transparent soap made under thesecond method may be saponified as

usual and consist of any good toiletbase. The soap is run to the crutcherand mixed with 95 per cent. alcohol inthe proportion of one part alcohol totwo parts of fatty acid contained in thesoap together with glycerine in thesame proportion.

By the third method castor oil alonemay be used to make the soap or addedto any of the above bases up to 33-1/3per cent. of the charge. If castor oilonly is used, but 2 per cent. or 3 percent. of sugar is required.

In the last method a combination of 80per cent. tallow, very low in free acid,20 per cent. cocoanut oil and 5 percent. W. W. rosin is a suitable charge.

The saponification and finishing iscarried out as with a full boiled soap.The soap is then placed into a jacketedvessel, provided with dry-steam coils,by which the excess water isevaporated from the soap until itcontains 73 per cent. fatty acids. Whenthe thick mass reaches this stage it isframed and when cool is suitable forobtaining a semi transparency whichnow depends upon the number of timesthe soap is milled, it being, of course,inferred that no solid matter of any sortbe added to the soap.

COLD MADE TRANSPARENT SOAP.

While transparent soaps may be made

by the above general methods they areusually made by the semi-boiled orcold process. By this process a moresatisfactory soap is obtained and it ismore simple to carry out. A detaileddescription of this method is best andmost easily given by using a typicalformula.

Charge:Tallow 193-1/2 lbs.Cochin Cocoanut Oil 169-1/2 "Castor Oil 89-1/2 "Soda Ash 7-3/4 "Soda Lye, 36 degs. B. 256 "Sugar (Cane) 198 "Alcohol 126 "

Water (Distilled) 80 "

To proceed, first place into a crutcheror jacketed kettle the oils and fat andheat to 140 degs. F. Then add the sodaash dissolved in about 30 pounds of thewater, after which the lye is added andthe mass stirred until a finger or stickrun over the surface leaves an imprint.Where the soap has reached this stage,it is well covered and allowed to standabout two hours or until it bulges in thecenter, after which the rest of the waterwhich should contain no lime or othermineral substance and which ispreferably distilled water, is added.The sugar is then slowly shoveled inwhile the mass is stirring and finally

the alcohol is poured in. The heat isthen increased to 160 degs. F. by drysteam and the soap crutched untildissolved. Under no circumstancesshould any soap be allowed to remainabove the surface of the mass on thesides of the mixer. This crutchingoperation consumes about one hour,and when finished the soap shouldstand in the vessel about half an hourwhen a small sample is taken out tocool. This sample should be clear andshow an excess of alkali. If it is notclear more alcohol is added, if not ofsufficient strength more lye put in untilthe desired condition is reached. Theperfume and color are now added.

The soap is then framed and allowed to

set after which it is cut, allowed to dryslightly and then pressed. To obtain apolished cake transparent soaps areoften planed before pressing and afterpressing polished with a soft cloth,dampened with alcohol. Instead offraming this soap, it is sometimes"tubed," that is to say, the soap fromthe crutcher is run into speciallyconstructed tubes of a shape near thatof the desired cake and allowed to cool,after which it is cut and pressed. Allscraps are returned to the crutcher, butin so doing the soap is slightlydarkened in color. It is advisable toexpose a finished cake of transparentsoap to the air for some time as by sodoing it becomes clearer.

Other formulae for cold madetransparent soaps made as just outlinedfollow:

I.Bleached Tallow 134 lbs.Cochin Cocoanut Oil 88 "Castor Oil 20 "W. W. Rosin 7 "Cane Sugar 64 "Water 32 "Glycerine 34 "Soda Lye, 38 degs. B. 135 "Alcohol 16 gal.II.Tallow 211 lbs.

Cochin Cocoanut Oil 185 "Castor Oil 97-1/2 "Soda Ash 8-1/2 "Water 106 "Soda Lye, 38 degs. B. 279 "Sugar 216 "Alcohol 137 "III.Castor Oil 60 lbs.Cochin Cocoanut Oil 195 "Tallow 120 "Alcohol 115 "Sugar 90 "Water 53 "Glycerine 53 "Soda Lye, 38 degs. B. 205-1/2 "

IV.

Tallow 100 lbs.Cochin Cocoanut Oil 100 "Castor Oil 60 "Glycerine 20 "Rosin, W. W. 20 "Sugar 40 "Water 50 "Soda Lye, 36 degs. B. 164 "Alcohol 8 gal.V.Tallow 174 lbs.Cocoanut Oil 114 "Soda Lye, 38 degs. B. 170 "Sugar 80 "

Water 72 "Alcohol 16 gal.

Rosin may be added in this formula upto 20 per cent. of fats used and thetallow cut down correspondingly.

SHAVING SOAPS.

The requirements of a shaving soap aresomewhat different than those of othersoaps. To be a good shaving soap thelather produced therefrom must beheavy, creamy, but not gummy, andremain moist when formed on the face.The soap itself should be of a softconsistency so as to readily adhere to

the face when used in stick form. Itshould furthermore be neutral or nearlyso to prevent the alkali from smartingduring shaving.

Shaving soap is made in the form of astick, and a tablet for use in the shavingmug. Some shavers prefer to have thesoap as a powder or cream, which areclaimed to be more convenientmethods of shaving. While a liquidshaving soap is not as well knownbecause it has not yet become popular,some soap for shaving is made in thisform.

Formerly shaving soap was extensivelymade from a charge of about 80 partstallow and 20 parts cocoanut oil as a

boiled settled soap, but either makingthe strengthening change with potashlye or using potash lye in saponifyingthe stock and graining with salt. Soapsfor shaving made in this manner arevery unsatisfactory, as they do notproduce a sufficiently thick or lastinglather and discolor very materiallyupon ageing. Potassium stearate formsan ideal lather for shaving, but readilyhardens and hence needs some of thesofter oils, or glycerine incorporatedwith it to form a satisfactory soap forshaving.

The selection of materials for making ashaving soap is important. The tallowused should be white and of high titer.Cochin cocoanut oil is to be preferred

to the other kinds, and the alkalisshould be the best for technical use thatcan be purchased—76 per cent. causticsoda and 88-92 per cent. caustic potashare suitable. By the use of stearic acidit is a simple matter to reach theneutral point which can be carefullyapproximated.

The following are shaving soapformulae which have been found togive good satisfaction:

I. lbs.Tallow 360Stearic acid 40Soda lye, 41° B. 147Potash lye, 34° B. 87

Water 32Gum tragacanth 1

II. lbs.Tallow 282Cocoanut oil 60Stearic acid 50Bayberry wax 18Soda lye, 41° B. 147Potash lye, 34° B. 90Water 32

III. lbs.Tallow 400Cocoanut oil 176Stearic acid 415Caustic soda, 40° B. 182

Caustic potash, 38° B. 108

To proceed, first run into the crutcherthe tallow, cocoanut oil and bayberrywax when used, and bring thetemperature of the mass up to140°-160° F. by dry steam. Then addthe caustic soda lye and keep on heatwith occasional mixing until it is alltaken up. When this stage is reachedgradually add all but about 5 per cent.of the potash lye, and complete thesaponification. This point having beenreached, the heat is turned off; thecrutcher is run and the stearic acid,previously melted by dry steam in alead-lined or enameled vessel, is run inin a continuous stream and the

crutching continued for fifteen minutesto half an hour. Samples are taken atthis time, cooled and tested byalcoholic phenolphthalein solution. Iftoo alkaline more stearic acid is added,if too acid more potash lye from thatpreviously reserved. After eachaddition of lye or stearic acid the massis crutched from 10 to 15 minuteslonger, another sample is taken, cooledand again tested. When thephenolphthalein shows a very lightpink after several minutes, the soap ispractically neutral, although at thispoint one can better judge bydissolving a sample in hot neutralizedalcohol made by putting into thealcohol a few drops of phenolphthalein,

and then adding weak alkali drop bydrop from a burette until a slight pink,not yellow, tint is obtained, and notingthe color of the solution. The solutionshould show a very light pink when thesoap is properly neutralized. When thisstage is arrived at the gum tragacanth,previously softened in water, iscrutched in if it is to be added. Thesoap is then framed, stripped in threeor four days, dried and milled.

The formulae as given are for shavingsticks, and do not readily press unlessthoroughly dried. A more satisfactoryresult is obtained by adding at the mill25 per cent. of white tallow base toobtain a satisfactory mug soap.

SHAVING POWDER.

Shaving powder differs from the soapsjust described in being pulverized,usually adding up to 5 per cent. starchto prevent caking. Any of the abovesoaps, dried bone dry, with or withoutthe addition of tallow base make asatisfactory powder for shaving.

SHAVING CREAM.

Shaving cream is now a very popularshaving medium due to the rapidity andconvenience with which one can shaveby the use of this product. Formerlyshaving cream was made from the

liquid oils like olive oil and a soft fatlike lard, together with cocoanut oil.Now, however, most of the popularshaving creams are made from stearicacid and cocoanut oil, as a far superiorproduct is obtained by the use of thesesubstances. By using these a moresatisfactory cream is obtained, and it isfar more convenient to make. Thelather also produced therefrom is moresuitable for shaving, being thick,creamy and remaining moist.

A few typical formulae for shavingcreams of this type are as follows:

I. lbs.Cochin cocoanut oil 26

Stearic acid 165Caustic potash lye, 50° B. 69Glycerine C. P. 76Water 38

II. lbs.Cochin cocoanut oil 18Stearic acid 73Caustic potash lye, 39° B. 54Glycerine 33Water 27

III. lbs.Cochin cocoanut oil 18Stearic acid 73Caustic potash lye, 39° B. 54Glycerine 20Water 40

and lbs.

Stearic acid 60Glycerine C. P. 85Water 165Sodium carbonate 50Borax 1

To make a shaving cream by Formula Ior II, the cocoanut oil and glycerine arefirst put into a suitable mixingapparatus or crutcher, and heated to120° F. A part or all the potash lye isthen added and the cocoanut oilsaponified. The rest of the potash lyeand the water are then added, and withthe mixer running the stearic acid,previously melted in a lead-lined or

enameled vessel, is then poured in in astream and the mass stirred untilsmooth, care being exercised not toaerate it too much. The cream is thentested for alkalinity, the best methodbeing by that described under shavingsoap, in which the sample is dissolvedin alcohol. Because of the largequantity of water present,phenolphthalein is unsatisfactory, asdissociation of the soap may show apink indication in spite of the fact themass is on the acid side. For a quickmethod of testing the bite on thetongue is a satisfactory criterion. If acooled sample bites the tongue morestearic acid is added until there is a 3%excess of this. When the proper

neutralization has taken place thecream is perfumed and framed in aspecial frame, or it may be allowed tocool in the mixer and perfumed thenext day. When cool the cream isstrained, or put through an ointmentmill, after which it is ready to fill intotubes.

The procedure for the first part ofFormula III is the same as that justgiven. The second part of the formulais made the same as a vanishing creamfor toilet purposes. To make this, firstmelt the stearic acid as alreadydirected. Dissolve the sodiumcarbonate and borax in water and whendissolved add the glycerine and stir.Then heat this solution to about

100°-120° F. and while stirring in asuitable mixing machine into whichthis solution has been poured afterbeing heated, or better still in which ithas been heated by dry steam, add thestearic acid. Continue mixing untilsmooth and then allow to cool, or runinto frames to cool.

When the shaving cream and vanishingcream are both cool, they are mixed inthe proportion of one of the former totwo of the latter. It is claimed that inthus making a shaving cream asmoother product is obtained, althoughit may be said that the vanishing creamis merely a soft soap and the ultimateresult is the same as though the variousingredients were added in one

operation, rather than making twoseparate products and then mixingthem, thereby considerably increasingthe cost of manufacture.

PUMICE OR SANDSOAPS.

Pumice and sand are at times added tosoap to aid in the removal of dirt incleansing the hands. In some casesthese soaps are made in the form of acake, in others they are sold in cans inthe form of a paste.

A hand paste is usually made bymerely dissolving ordinary tallow basein two or three times its weight of hot

water and mixing in the desiredquantity of pumice or sand and in someinstances adding a little glycerine tokeep it soft or a solvent of some kindfor grease. It may also be made bydirectly incorporating any of these in apotash soap.

A cold made or semi-boiled cocoanutor palm kernel oil soap is the base usedto add the pumice or sand to in makinga cake soap of this sort. The followingformulae serve as a guide for thesesoaps.

I.Palm Kernel or CeylonCocoanut Oil 705 lbs.

Pumice (Powdered) 281 "Soda Lye, 38° B. 378 "II.Cocoanut Oil 100 "Soda Lye, 38° B. 55 "Water 6 "Silver Sand (fine) 60 "

To proceed place the oil in a crutcherand heat to 140° F. Sift in the pumiceand mix thoroughly. The lye is thenadded which causes a curdling of thegrain. The stirring is continued untilthe grain closes and the soap is smooth,after which the desired perfume isadded and the soap dropped into aframe and crutched by hand. When the

soap is set, it is slabbed, cut into cakes,dried slightly and pressed.

LIQUID SOAPS.

Liquid soaps are merely solutions of apotash soap, usually cocoanut oil soap,although corn oil is used to make acheap soap. One of the difficultiesencountered in liquid soap is to keep itclear. At a low temperature a sedimentis often formed, but this can beovercome by the use of sugar andfiltering the soap through a filter pressat a low temperature. In order toprevent the soap from freezing, it isnecessary to lower the freezing pointby the addition of glycerine or alcohol.

To make liquid soap by any of theformulae given below, the oil is firstrun into a jacketed kettle with a stirringdevice, and heated to about 120° F. Thepotash lye is then added and the oilsaponified. When the saponificationtakes place, especially when cocoanutoil is used, the mass swells rapidly andmay foam over the sides of the kettleunless water is used to check this, or akettle of about four to five times thecapacity of the total charge of soap isused. When the saponification hasoccurred, the sugar, borax andglycerine are added, the water run inand the mixture stirred until the soap isthoroughly dissolved. Heat aidsmaterially in dissolving the soap. The

soap is then allowed to cool and ifcolor or perfume is to be added this isstirred in, after which the soap iscooled and filtered or else run directlyinto barrels.

Tallow is not suitable for making aclear liquid soap since it is too high instearine which when formed into thestearate makes an opaque solution. Theformulae herewith given have beenfound to give good practical results.

I. lbs.Cocoanut oil 130Caustic potash lye, 28° B. 135Sugar 72Borax 2

Water 267II. lbs.

Corn oil 130Caustic potash lye, 26° B. 135Sugar 72Borax 2Water 267

III. lbs.Cocoanut oil 100Caustic potash lye, 28° B. 102Glycerine 100Sugar 70Water 833

Formulae I and II contain about 20 percent. fatty acids. It is possible, of

course, to either increase or decreasethe percentage of fatty acid by varyingthe amount of water. The water used inmaking liquid soaps, of course, shouldbe soft, for hard water forms insolublesoaps which precipitate and cause asediment.

USE OF HARDENED OILSIN TOILET SOAPS.

While the introduction of thehydrogenation of oils is a decidedadvance in the production of suitablecheaper oils for soap making,comparatively little hardened oil isemployed for soap making in America

up to the present time. In Europe,however, considerable advance hasbeen made by the use of such oils formanufacturing soap therefrom and anumber of plants turn out largequantities of hydrogenated oils for soapmaking as well as for edible purposes.Recently a company has been formedin this country for hardening oils and itis very probable that the future will seethis material extensively used in ourown country, as these appear to be theone present hope of the soapmanufacturer as a check on the everincreasing cost of fats and oils nowused in making soap.

It is an unfortunate condition thathydrogenated oils produced abroad are

sold under names which giveabsolutely no indication as to the oilwhich has been hardened. The softerand cheaper oils like fish oil, linseedoil, cottonseed oil, etc., are generallyhardened for soap manufacture todifferent degrees of hardness. While itis impossible to definitely state justwhat products as Candelite, Talgol,Krutolin or several other coined namesof hardened oils are, variousinvestigators have experimented withthem as to their adaptability forproducing toilet soaps and found thatsuitable toilet soaps may be made fromthem. While many objections were atfirst met with concerning soaps madefrom these products, as to their

unsatisfactory saponification, the poorlathering quality of the soaps and theirodor and consequent difficulty inperfuming, the results of mostinvestigators along these lines indicatethat these in many cases were due toprejudice against or unfamiliarity withhandling oils of this type for soapmaking.

In manufacturing soap from hardenedoils it is usually necessary toincorporate with the charge lard,tallow, tallow oil or some other soft oilof this nature. Satisfactory bases fortoilet soaps, made as boiled settledsoap by the use of Talgol (undoubtedlyhardened fish oil), are said to be made

by the formulae[10] below.

I.Tallow 45 partsTalgol 40 "Cocoanut Oil 15 "II.Cocoanut Oil (Ceylon) 6 "Tallow 12 "Talgol, Extra 12 "

The method of boiling a soap of thistype does not differ materially fromthat of making settled tallow soap base.The soap itself has a different odorthan a straight tallow base, but is saidto make a very satisfactory soap formilling and to be of good appearance.

Satisfactory transparent soaps are madefrom the hardened oil Candelite, whichreplaces the tallow in transparent soapformulae such as have already beengiven in the section under "TransparentSoaps." The method of manufacturing asoap by the use of this product varies inno way from the usual methodemployed for making these soaps.

Since hydrogenated oils are high instearine, their use in shaving soaps is adecided advantage. It has previouslybeen pointed out that potassiumstearate forms an ideal lather forshaving, and in the hydrogenatingprocess the olein is converted tostearine. Thus a hardened oil isadvantageous in a shaving soap. As an

example of a cold made soap forshaving the following may betaken.[11]

Talgol Extra 50 lbs.Cocoanut Oil 10 "Lard 10 "Soda Lye, 38° B. 20 "Potash Lye, 37° B. 21 "

This soap may be made in a crutcher bythe method generally used in makingsoap by the cold process.

TEXTILE SOAPS.

Soap is a very important product to

every branch of the textile industry.For woolen fabrics it is used forscouring, fulling and throwing thewool; in the silk industry it isnecessary for degumming the raw silk,as well as for dyeing; in the cottonmills it is used to finish cotton clothand to some extent in bleaching; it is,furthermore, employed in a number ofways in the manufacture of linen.Large quantities of soap are thusconsumed in an industry of so great anextent and the requirements necessitatedifferent soaps for the differentoperations. We will, therefore, considerthese in detail.

SCOURING AND

FULLING SOAPS FORWOOL.

The soaps used to scour wool and forfulling the woven cloth are usuallymade as cheaply as possible. They are,however, generally pure soaps, asfilling material such as sodium silicatedoes not readily rinse out of the wooland if used at all must be added verysparingly. Both cold made and boiledsettled soaps are made for this purpose.The soap is generally sold in barrels,hence is run directly to these from thecrutcher or soap kettle. As cold madesoaps the following serve for woolscouring or fulling.

I.

Palm Oil 200lbs.

Bone Grease 460 "Soda Lye, 36° B. 357 "Water 113 "Soda Ash 50 "Citronella 2 "II.Palm Oil (Calabar,unbleached) 155 "

House Grease 360 "Soda Lye, 36° B. 324 "Water 268 "Sodium Silicate 83 "III.

House Grease 185 "Palm Oil (unbleached) 309 "Soda Lye, 36° B. 309 "Water 391 "Soda Ash 70 "Sodium Silicate 60 "Corn Starch 10 "

These soaps are made in a crutcher bythe usual process for cold-made soaps,crutched until smooth, dropped into abarrel and crutched by hand the nextday or just before cooling.

As a settled soap for these operationsthe following charge is typical:

Palm Oil 34 parts

Cottonseed foots or itsequivalent in fatty acids

33 "

Rosin 10 "House Grease 23 "

The method of boiling such a soap isthe same as for any settled soap up tothe strengthening change. When thisstage is reached, sufficient lye is addedto strengthen the kettle strongly. It isthen boiled down with closed steam onsalt brine or "pickle" until a sample ofthe lye taken from the bottom stands at16°-22° B. The soap is then run intobarrels and after standing therein for aday is hand crutched until cool toprevent streaking of the soap.

Besides a soap of this type a settledtallow chip soap is used.

WOOL THROWER'SSOAP.

Soaps for wool throwing are sometimesmade from olive oil foots but these areoften objected to because of thesulphur-like odor conveyed to the clothdue to the method by which this oil isextracted with carbon disulphide. Apotash soap hardened somewhat withsoda is also used. As a formula for asuitable soap of this type this may begiven.

Olive Oil Foots 12 parts

Corn Oil 46 "House Grease 20 "Soda Lye, 36° B. 3 "Potassium Carbonate (dry) 5-3/4 "Potassium Hydrate (solid) 23 "

This soap is made as a "run" soap bythe general directions already given fora soap thus made. The kettle is boiledwith open and closed steam, addingwater very slowly and aiming to obtaina 220-225 per cent. yield or fatty acidcontent of the finished soap of 46 percent. When the soap is finished asample cooled on a plate of glassshould be neither slippery or short, butshould string slightly. The finishedsoap is run directly into barrels.

A soap for wool throwing by the semi-boiled process may be made from oliveoil foots in a crutcher thus:

Olive Oil Foots 600 lbs.Potash Lye, 20° B. 660 "

The oil is heated to 180° F., the lyeadded and the mass stirred until itbunches, when it is dropped intobarrels.

WORSTED FINISHINGSOAPS.

For the finishing of worsted cloth soapshigh in cocoanut oil or palm kernel oilare preferred. These soaps are finished

very neutral, being made as settledsoaps, but given an extra wash changeafter strengthening strongly. They arethen finished as usual and run intobarrels. If framed too hot, the highpercentage of cocoanut oil causesmottling, which is prevented bycrutching by hand until the temperatureof the soap is 140°-145° F. Sometypical charges, all of which aresaponified with soda lye, follow:

I.

Palm Kernel Oil 60parts

Corn Oil 40 "II.Palm Kernel Oil 30 "

Red Oil (single pressed) 70 "III.

Red Oil 33-1/3"

Corn Oil 33-1/3"

Cocoanut Oil or Palm KernelOil

33-1/3"

SOAPS USED IN THESILK INDUSTRY.

Soap is used to a very large extent insilk mills, both for degumming the rawsilk and in silk dyeing. Raw silkconsists of the true silk fibre known asfibroin and a gummy coating, sericin,

which dulls the lustre of the silk unlessremoved. For this purpose a slightlyalkaline olive oil foots soap is bestadapted, although palm oil and peanutoil soaps are sometimes used, as wellas soaps made from a combination ofhouse grease to the extent of 30 percent., together with red oil or straightolein soaps, both of which areartificially colored green. In usinghouse grease, if 30 per cent. isexceeded in combination with red oil,the titer is raised to such an extent thatthe soap does not readily rinse from thesilk nor dissolve readily. They are alsonot advisable because they impart adisagreeable odor to the silk.

To make a soap for this purpose from

olive oil foots it is made as a settledsoap, care being taken to thoroughlyboil the mass on the saponificationchange in the closed state to assureproper saponification. The kettle isusually grained with lye and given agood wash change to remove the excessstrength. The change previous to thefinish should not be too heavy or toolarge a nigre results. The lighter thegrain is, the better the finished kettleis. A yield of 150 per cent. is usuallyobtained. This soap is generally run toa frame, slabbed upon cooling andpacked directly into wooden cases.

For silk dyeing the above soap issuitable, although any well-made soapof good odor and not rancid is useable.

While soap alone is often used in thebath for silk dyeing, certain dyestuffsrequire the addition of acetic orsulphuric acid, which sets free the fattyacids. If these be of bad odor it is takenup by the silk and is difficult toremove. The most generally used soapsare the just mentioned olive foots soapor a soap made from a good grade redoil.

Both kinds are extensively used.

SOAPS USED FORCOTTON GOODS.

In the manufacture of cotton goods, ascompared to the wool and silk

industries, very much less soap is usedand it is only applied to the finishedfabric either to clean the clothpreparatory to dyeing or to aid indyeing with certain colors. It is alsoused in calico printing. For cleansingthe cloth ordinary chip soap is suitablealthough a more alkaline soap finishedas a curd soap is an advantage in thatthe free alkali contained therein aids inremoving the dirt and has no harmfuleffect on the cotton. For dyeing cottongoods or to brighten certain colors afterdyeing an olive oil foots soap is mostgenerally employed. In calico printingsoap is used to wash and clear the clothafter printing. A soap for this purposeshould be easily soluble in water and

contain no free alkali, rosin or filler.The best soaps for use in calicoprinting are either an olive oil footssoap or an olein soap.

SULPHONATED OILS.

While sulphonated oils are not used toany great extent in the manufacture ofsoap, they are used very largely in thedyeing and printing of turkey andalizarine reds on cotton as well as othercolors. Just what action these oils haveis not known. Turkey red oil orsulphonated castor oil is the bestknown sulphonated oil.

The process of making these oils is

simple. The equipment necessary is awooden tank or barrel of suitablecapacity, approximately two and a halftimes the amount of oil to be treated.There are furthermore required othertanks or vessels to hold the solutionsused such as caustic soda, ammoniaand acid. The tank to be used for thepreparation of sulphonated oil shouldbe provided with a valve at the bottomof the tank and a gauge to measure thequantity of liquid therein.

The process is carried out as follows:

Three hundred pounds of castor oil areplaced in the tank and 80 pounds at 66deg. B. sulphuric acid are weighed outin another vessel. The acid is run into

the tank containing the oil in a verythin stream while the oil is well stirred.At no time should the temperatureexceed 40 deg. C. This operationshould consume at least an hour andstirring should be continued half anhour longer to insure the thoroughmixing of the oil with the acid. Themass is then allowed to settle for 24hours, after which 40 gallons of waterare added and the mixture stirred untilit has a uniform creamy colorindicating no dark streaks. This mixingprocess should be carefully carried outand when completed allowed to settle36 hours. At this point the mass willhave separated into two layers, thelower layer consisting of a water

solution of acid and the upper layer ofoil. The former is run out through thevalve located at the bottom of the tank.Another wash may now be given ordispensed with as desired. In this washthe addition of salt or sodium sulphateat the rate of 1-1/2 pounds per gallon ofwater is advisable. A 24 deg. B. causticsoda solution is prepared and addedslowly to the acidified oil with constantstirring. The mass first turns creamy,then becomes streaked, increasing instreaks as the caustic solution is pouredin, and finally becomes clear andtransparent. Water is now added tobring the volume to 75 gallons. The oilis now milky in appearance, but theaddition of a little more soda solution

restores the transparency.

In some cases ammonia is used inaddition to caustic soda in neutralizingthe oil. Three-fourths of the amount ofcaustic soda required to complete theneutralization is first added and thenthe neutralization is completed with aone to one liquid ammonia and watersolution.

FOOTNOTES:

[9] Seifensieder Ztg., 40, 47, 1266(1913).

[10] Seifensieder Ztg. (1913), p. 334and 338.

" " (1912), p. 1229 and

1257.

[11] Seifensieder Ztg. (1912), p.954.

CHAPTER V

Glycerine Recovery.

The recovery of glycerine is veryclosely allied with the soap-makingindustry, because glycerine is the veryvaluable by-product obtained in thesaponification of oils and fats. No soapplant is, therefore, fully equippedunless it has some method whereby theglycerine is recovered and theimportance of recovering this productcannot be too strongly emphasized.

It has already been pointed out that

neutral fats or the glycerides are acombination of fatty acid withglycerine. These are split apart in theprocess of saponification. While by thet e r m saponification as used in soapmaking it is inferred that this is thecombination of caustic alkalis with thefatty acids to form soap, this term is byno means limited to this method ofsaponification, as there are variousother methods of saponifying a fat. Thechemical definition of saponification isthe conversion of an ester, of whichglycerides are merely a certain type,into an alcohol and an acid or a salt ofthis acid. Thus, if we use caustic alkalias our saponifying agent for a fat or oil,we obtain the sodium or potassium salt

of the higher fatty acids or soap and thealcohol, glycerine. On the other hand,if we use a mineral acid as thesaponifying agent, we obtain the fattyacids themselves in addition toglycerine. While the former is by farthe most generally employed formaking soap, other processes consist insaponifying the fats by some methodother than caustic alkalis and thenconverting the fatty acids into soap byeither neutralizing them with sodiumor potassium carbonate or hydrate.

It is important to again point out herethat fats and oils develop free fatty acidof themselves and that the developmentof this acid represents a loss inglycerine. The selection of an oil or fat

for soap making should therefore to alarge extent be judged as to itsadaptability by the free fatty acidcontent, as the higher this content is,the greater is the loss in the glycerineeventually obtained. Glycerine oftenrepresents the only profit to a soapmanufacturer. It is indeed necessary todetermine the percentage of free fattyacid before purchasing a lot of stock tobe made into soap.

In taking up the question of glycerinerecovery we will consider the variousmethods thus:

1. Where the glycerine is obtainedfrom spent lye by saponifying the fatsor oils with caustic alkali.

2. Where the glycerine is obtained bysaponifying the fats or oils by someother method than the above, of whichthere are the following:

(a) Twitchell process.(b) Saponification by lime inautoclave.(c) Saponification by acid.(d) Saponification by water inautoclave.(e) Fermentative (Enzymes).(f) Krebitz process.

RECOVERY OFGLYCERINE FROM

SPENT LYE.

The spent lye obtained from theglycerine changes in making soapvaries greatly, the quality dependingupon the stock saponified and the soapmaker's care in handling the operation.No two lyes run exactly alike as toproportion of the various ingredients,although they are all similar incontaining the same substances eitherin solution or suspension. Spent lye is awater solution of mainly glycerine, freealkali either as caustic alkali orcarbonate and salt, including sodiumsulfate, but furthermore contains somesoap and albuminous matter either insolution or suspension. Upon standingin the storage tank the greater part ofthe soap usually separates when the lye

cools. In order to assure the greatesteconomical yield of glycerine bysaponifying a fat with caustic soda it isnecessary to obtain a proportion ofthree parts of water to every part of fatmade into soap. Test runs have shownthat this is the proper proportion andthat it is not economical to greatlyexceed this amount, and if a much lessproportion is used the full yield ofglycerine is not obtained.

The spent lyes contain varying amountsof glycerine, the first change beingrichest in glycerine content, and thisbeing reduced in the subsequentchanges. If the lyes always run high inglycerine it is an indication that it isnot all being obtained. The usual

percentage is from 0.5% to 5% or evenmore, although the average issomewhere around 2% to 3%. The lyeas it comes from the kettle should notcontain any more than 0.5% to 0.6% offree alkali calculated as sodiumcarbonate, Na2CO3. If the proportion ishigher than this, it shows that thesaponification has been conducted withtoo high a proportion of alkali, acondition which should be corrected inthe kettle room. An excess of freealkali does not interfere to any greatextent with the successful recovery ofthe glycerine, but is a waste of bothalkali and the acid used in neutralizingthis. It is, therefore, more economicalto run a strong lye over fresh stock and

neutralize the alkali thus, rather thantreating the lye for glycerine recovery.

Before the spent lye can be run into theevaporator it is necessary to removethe albuminous impurities and soapand to neutralize the excess alkali tobetween exactly neutral and 0.02%alkalinity. The lye should never be fedinto the evaporator in the acidcondition.

In order to treat the spent lyes forevaporation, they are first allowed tocool in the storage tank, after whichany soap which may have separated isskimmed off and returned to the soapkettle. This lye is then pumped to thetreatment tank, an ordinary tank

equipped with some method ofagitating the liquor, either by amechanical stirrer, steam blower orcompressed air, until it is about twofeet from the top.

After the lye has been skimmed off it isthoroughly agitated and a sampletaken. The amount of lye in the tank isthen calculated. Spent lye is about 1.09times heavier than water, or weighsabout 9 pounds to the gallon. While thesample is being tested for alkalinity itis advisable to add sulfate of alumina,which may be dissolving while thesample is being titrated. This substanceshould be added in the proportion ofanywhere from 6 to 14 pounds perthousand pounds of lye, depending

upon the amount of impuritiescontained therein. For a clean lye sixpounds per thousand is sufficient, butfor an impure lye a greater quantity isnecessary. The sulfate of alumina usedshould be free from arsenic andsulfides and should contain a minimumamount of grit (silica), as grit reducesthe life of the pump valves. This maybe estimated with sufficient accuracyby rubbing the filtered-off portions,insoluble in water between the fingersand a plate of glass. The object ofadding the sulfate of alumina is totransform the soap contained in the lyeinto the insoluble aluminum soaps, andat the same time to coagulate thealbuminous impurities. It must be

remembered that the sulfate of aluminais added only for the fresh lye put intothe tank. Thus if there were 10,000pounds of lye in the treating tank whenthe fresh lye was run in, and 50,000pounds when the tank is filled, addingnine pounds of sulfate of alumina perthousand of lye, only 360 poundswould be added or enough for 40,000pounds. Sulfate of alumina neutralizesone-third of its weight of caustic.

To determine the alkali in the sample,10 cubic centimeters are pipetted into abeaker, a little distilled water added,then 3 or 4 drops of phenolphthaleinindicator. From a burette, quarternormal (N/4) sulfuric acid is addeduntil the pink color is just discharged.

When this point is reached 4 to 5 c. c.more of acid are added and the solutionis boiled to expel the carbon dioxide.Should the solution turn pink, it isnecessary to add more acid. Afterhaving boiled for 3 to 4 minutes, N/4caustic soda is added until the pinkcolor just returns and the amount ofcaustic soda used is read on the burette.The difference between the number ofcubic centimeters of N/4 sulfuric acidand N/4 caustic soda gives the amountof alkali in the sample. By using a 10 c.c. sample and N/4 sulfuric acid and N/4caustic soda each c. c. obtained by thedifference of these two solutions isequal to one-tenth of one per cent.(0.1%) of the total alkali in the lye. As

an example, say we first used 7.7 c. c.of N/4 sulfuric acid to just dischargethe pink, then added 4 c. c. more, or11.7 c. c. in total. After boiling itrequired 5.3 c. c. to bring back a slightpink, the total alkalinity would be 11.7c. c. - 5.3 c. c. = 6.4 c. c., or 0.64% totalalkali in the lye in terms of causticsoda. If there were 40,000 pounds oflye to be treated then we should have toneutralize:

40,000 × .0064 = 256 lbs. alkali. Sincesulfate of alumina neutralizes one-thirdof its weight in caustic, and there aresay 9 lbs. of this added per thousandpounds of lye we would add

40,000 × 9 = 360 lbs. of sulfate of

alumina. This would neutralize 360 ×1/3 = 120 lbs of alkali. There are then256 - 120 = 136 lbs. of alkali still to beneutralized. If 60° B. sulfuric acid isused it requires about 1.54 lbs. of acidto one pound of caustic. Therefore toneutralize the caustic soda remaining itrequires:

136 × 1.54 = 209.44 lbs. 60° B. sulfuricacid to neutralize the total alkali in the40,000 pounds of spent lye.

The acid is added and the lye wellstirred, after which another sample istaken and again titrated as before.From this titration the amount of acidto be added is again calculated andmore acid is added if necessary. Should

too much acid have been added, causticsoda solution is added until the lye isbetween exactly neutral and 0.02%alkaline. The filtered lyes at this stagehave a slight yellowish cast.

To be sure that the lyes are treatedcorrectly the precipitation test isadvisable. To carry this out filter about50 c. c. of the treated lye and divideinto two portions in a test tube. To oneportion add ammonia drop by drop. If acloudiness develops upon shaking,more alkali is added to the lye in thetank. To the other portion add a fewdrops of 1 to 5 sulfuric acid and shakethe test tube. If a precipitate developsor the solution clouds, more acid isneeded. When the lyes are treated right

no cloudiness should develop eitherupon adding ammonia or the diluteacid.

The properly treated lye is then runthrough the filter press while slightlywarm and the filtered lye is fed to theevaporator from the filtered lye tank.The lye coming from the filter pressshould be clear and have a slightyellowish cast. As the pressureincreases it is necessary to clean thepress or some of the press cake willpass through the cloths. Where sodiumsilicate is used as a filler, the silicatescrap should never be returned to thesoap kettle until the glycerine lyes havebeen withdrawn. This practice of somesoapmakers is to be strongly censured,

as it causes decided difficulty infiltering the lye, since during thetreatment of the lye, free silicic acid incolloidal form is produced by thedecomposition of the sodium silicateby acid. This often prevents filteringthe treated lye even at excess pressureand at its best retards the filtering.

As to the filter press cake, this may bebest thrown away in a small factory.Where, however, the output ofglycerine is very large it pays torecover both the fatty acids andalumina in the press cakes.

In some cases, especially when the lyesare very dirty and the total residue inthe crude glycerine runs high, for

which there is a penalty usuallyattached, a double filtration of the lyeis advisable. This is carried out by firstmaking the lye slightly acid in reactionby the addition of alum and acid, thenfiltering. This filtered lye is thenneutralized to the proper point withcaustic, as already described, andpassed through the filter press again.

While in the method of treating thelyes as given sulfuric acid is used forneutralizing, some operators prefer touse hydrochloric acid, as this formssodium chloride or common salt,whereas sulfuric acid forms sodiumsulfate, having 3/5 the graining powerof salt, which eventually renders thesalt useless for graining the soap, as the

percentage of sodium sulfate increasesin the salt. When the salt contains 25per cent. sodium sulfate it is advisableto throw it away. Sulfuric acid,however, is considerably cheaper thanhydrochloric and this more thancompensates the necessity of having toeventually reject the recovered salt. Itmay here also be mentioned thatrecovered salt contains 5-7 per cent.glycerine which should be washed outin the evaporator before it is thrownaway. The following tables give theapproximate theoretical amounts ofacids of various strengths required toneutralize one pound of caustic soda:

For 1 pound of caustic soda—

3.25 lbs. 18°B.

hydrochloric (muriatic) acid

2.92 " 20°B. " " "

2.58 " 22°B. " " "

For 1 pound of caustic soda—

1.93 lbs. 50°B. sulphuric acid are required.

1.54 " 60°B. " " " "

1.28 " 66°B. " " " "

It is, of course, feasible to neutralizethe spent lye without first determining

the causticity by titrating a sample andthis is often the case. The operatorunder such conditions first adds thesulfate of alumina, then the acid, usinglitmus paper as his indicator.Comparatively, this method oftreatment is much slower and not aspositive, as the amount of acid or alkalito be added is at all times uncertain, forin the foaming of the lyes their actionon litmus is misleading.

After the lye has been filtered to thefiltered lye tank it is fed to theevaporator, the method of operation ofwhich varies somewhat with differentstyles or makes. When it first entersthe evaporator the lye is about 11°-12°B. After boiling the density will

gradually rise to 27° B. and remain atthis gravity for some time and duringwhich time most of the salt is droppedout in the salt filter. As the lyeconcentrates the gravity gradually risesto 28°-30° B., which is half crudeglycerine and contains about 60 percent. glycerine. Some operators carrythe evaporation to this point andaccumulate a quantity of half crudebefore going on to crude. After halfcrude is obtained the temperature onthe evaporator increases, the vacuumincreases and the pressure on thecondensation drain goes up (using thesame amount of live steam). As theliquor grows heavier the amount ofevaporation is less, and less steam is

required necessitating the regulation ofthe steam pressure on the drum. Whena temperature of 210° F. on theevaporator, with 26 or more inchesvacuum on the pump is arrived at, thecrude stage has been reached and theliquor now contains about 80 per cent.glycerine in which shape it is usuallysold by soap manufacturers. A greaterconcentration requires more intricateapparatus. After settling a day in thecrude tank it is drummed.

Crude glycerine (about 80 per cent.glycerol) free from salt is 33° B., orhas a specific gravity of 1.3. A sampleboiled in an open dish boils at atemperature of 155° C. or over.

TWITCHELL PROCESS.

The Twitchell process of saponificationconsists of causing an almost completecleavage of fats and oils by the use ofthe Twitchell reagent or saponifier, asulfo-aromatic compound. This ismade by the action of concentratedsulfuric acid upon a solution of oleicacid or stearic acid in an aromatichydrocarbon. From 0.5 per cent. to 3per cent. of the reagent is added andsaponification takes place from 12-48hours by heating in a current of livesteam. The reaction is usuallyaccelerated by the presence of a fewper cent. of free fatty acids as a starter.Recently the Twitchell double reagent

has been introduced through which it isclaimed that better colored fatty acidsare obtained and the glycerine is freefrom ash.

The advantages claimed for theTwitchell process as outlined byJoslin[12] are as follows:

1. All the glycerine is separated fromthe stock before entering the kettle,preventing loss of glycerine in the soapand removing glycerine from spent lye.

2. The liquors contain 15-20 per cent.glycerine whereas spent lyes containbut 3-5 per cent. necessitating lessevaporation and consequently beingmore economical in steam, labor and

time.

3. No salt is obtained in the liquorswhich makes the evaporation cheaperand removes the cause of corrosion ofthe evaporator; also saves the glycerineretained by the salt.

4. The glycerine liquors are purer andthus the treatment of the lyes ischeaper and simpler and theevaporation less difficult.

5. The glycerine can readily beevaporated to 90 per cent. crude ratherthan 80 per cent. crude, thus savingdrums, labor in handling and freight.The glycerine furthermore receives ahigher rating and price, being known as

saponification crude which develops noglycols in refining it.

6. The fatty acids obtained by theTwitchell saponifier may be convertedinto soap by carbonates, thus savingcost in alkali.

7. There is a decrease in the odor ofmany strong smelling stocks.

8. The glycerine may be obtained fromhalf boiled and cold made soaps as wellas soft (potash) soaps.

While the advantages thus outlined areof decided value in the employment ofthe Twitchell process, the one greatdisadvantage is that the fatty acidsobtained are rather dark in color and

are not satisfactorily employed for themaking of a soap where whiteness ofcolor is desired.

To carry out the process the previouslyheated oil or fat to be saponified is runinto a lead lined tank. As greases andtallow often contain impurities apreliminary treatment with sulfuricacid is necessary. For a grease 1.25 percent. of half water and half 66° B.sulfuric acid is the approximateamount. The undiluted 66° B. acidshould never be added directly, as thegrease would be charred by this. Thegrease should be agitated by steamafter the required percentage of acid,calculated on the weight of the grease,has been added. The wash lye coming

off should be 7°-10° B. on a good cleangrease or 15°-22° B. on cotton oil or apoor grease. As has been stated thegrease is heated before the acid isadded or the condensation of the steamnecessitates the addition of more acid.After having boiled for 1-2 hours thegrease is allowed to settle for 12 hoursand run off through a swivel pipe.

After the grease has been washed, asjust explained, and settled, it is pumpedinto a covered wooden tank containingan open brass coil. Some of the secondlye from a previous run is usually leftin this tank and the grease pumped intothis. The amount of this lye should beabout one-third to one-half the weightof the grease so that there is about 60

per cent. by weight of grease in thetank after 24 hours boiling. Whereoccasions arise when there is no secondlye about 50 per cent. by weight ofdistilled water to the amount of greaseis run into the tank to replace the lye.The saponifier is then added through aglass or granite ware funnel after thecontents of the tank have been broughtto a boil. If the boiling is to becontinued 48 hours, 1 per cent. ofsaponifier is added. For 24 hoursboiling add 1.5 per cent. The boiling iscontinued for 24-48 hours allowing 18inches for boiling room or the greasewill boil over.

After boiling has continued therequired length of time the mass is

settled and the glycerine water is drawnoff to the treatment tank. Should apermanent emulsion have formed, dueto adding too great an amount ofsaponifier, a little sulfuric acid (0.1 percent.-0.3 per cent.) will readily breakthis. During the time this is being donethe space between the grease and thecover on the tank is kept filled withsteam as contact with the air darkensthe fatty acids.

To the grease remaining in the tankdistilled water (condensed water fromsteam coils) to one-half its volume isadded and the boiling continued 12-24hours. The grease is then settled andthe clear grease run off through aswivel pipe. A layer of emulsion

usually forms between the clear greaseand lye so that it may easily bedetermined when the grease has allbeen run off. To prevent discolorationof the fatty acids it is necessary toneutralize the lye with bariumcarbonate. The amount of this to beadded depends upon the percentage ofsaponifier used. About 1/10 the weightof saponifier is the right amount. Thebarium carbonate is added through thefunnel at the top of the tank mixed witha little water and the lye tested until itis neutral to methyl orange indicator.When the fatty acids are thus treatedthey will not darken upon exposure tothe air when run off.

Fresh grease is now pumped into the

lye or water remaining in the tank andthe process repeated.

The glycerine water or first lye is runto the treatment tank, the fat skimmedoff and neutralized with lime until itshows pink with phenolphthalein, afterhaving been thoroughly boiled withsteam. About 0.25 per cent. lime is theproper amount to add. The mixture isthen allowed to settle and thesupernatant mixture drawn off and runto the glycerine evaporator feed tank.The lime which holds considerableglycerine is filtered and the liquoradded to the other. The evaporation iscarried out in two stages. The glycerinewater is first evaporated to about 60per cent. glycerol, then dropped into a

settling tank to settle out the calciumsulfate. The clear liquor is thenevaporated to crude (about 90 per cent.glycerine) and the sediment filteredand also evaporated to crude.

As to the amount of saponifier to useon various stocks, this is bestdetermined by experiment as to howhigh a percentage gives dark coloredfatty acids. For good stock such asclean tallow, prime cottonseed oil, cornoil, cocoanut oil and stock of this kind0.75 per cent. saponifier is sufficient.For poorer grades of tallow, housegrease, poor cottonseed oil, etc., 1 percent. saponifier is required and forpoorer grade greases higherpercentages. The percentage of fatty

acids developed varies in variousstocks, and also varies with the carethat the operation is carried out, but isusually between 85 per cent.-95 percent. Due to the water taken up in thesaponification process there is a yieldof about 103 pounds of fatty acids andglycerine for 100 pounds of fat.

The Twitchell reagent has undoubtedlycaused a decided advance in thesaponification of fats and oils and hasbeen of great value to the soapmanufacturer, because with a smallexpenditure it is possible to competewith the much more expensiveequipment necessary for autoclavesaponification. The drawback,however, has been that the reagent

imparted a dark color to the fatty acidsobtained, due to decompositionproducts forming when the reagent ismade, and hence is not suitable for usein soaps where whiteness of color isdesired.

There have recently been two newreagents introduced which act ascatalyzers in splitting fats, just as theTwitchell reagent acts, but the fattyacids produced by the cleavage are ofgood color. The saponification,furthermore, takes place more rapidly.These are the Pfeilring reagent andKontact reagent.

The Pfeilring reagent is very similar tothe Twitchell reagent, being made from

hydrogenated castor oil andnaphthalene by sulfonation withconcentrated sulfuric acid. It ismanufactured in Germany and is beingextensively used in that country withgood success.

The Kontact or Petroff reagent,discovered by Petroff in Russia, ismade from sulfonated mineral oils.Until very recently it has only beenmanufactured in Europe, but now thatit has been found possible to obtain theproper mineral constituent fromAmerican petroleum, it is beingmanufactured in this country, and it isvery probable that it will replace theTwitchell reagent because of theadvantages derived by using it, as

compared to the old Twitchell reagent.

The method and equipment necessaryfor employing either the Pfeilring orKontact reagents is exactly the same asin using the Twitchell process.

AUTOCLAVESAPONIFICATION.

While the introduction of the Twitchellprocess to a great extent replaced theautoclave method of saponification forobtaining fatty acids for soap making,the autoclave method is also used. Thisprocess consists in heating thepreviously purified fat or oil in thepresence of lime and water, or water

only, for several hours, which causes asplitting of the glycerides into fattyacids and glycerine. The advantage ofautoclave saponification over theTwitchell process is that a greatercleavage of the fats and oils results inless time and at a slightly less expense.The glycerine thus obtained is alsopurer and of better color than thatobtained by Twitchelling the fats.

An autoclave or digestor consists of astrongly constructed, closed cylindricaltank, usually made of copper, and is sobuilt as to resist internal pressure. Thedigestor is usually 3 to 5 feet indiameter and from 18 to 25 feet high. Itmay be set up horizontally or verticallyand is covered with an asbestos jacket

to retain the heat. Various inlets andoutlets for the fats, steam, etc., as wellas a pressure gauge and safety valveare also a necessary part of theequipment.

LIME SAPONIFICATION.

The saponification in an autoclave isusually carried out by introducing thefats into the autoclave with apercentage of lime, magnesia or zincoxide, together with water. If the fatscontain any great amount of impurities,it is first necessary to purify themeither by a treatment with weaksulfuric acid, as described under theTwitchell process, or by boiling them

up with brine and settling out theimpurities from the hot fat.

To charge the autoclave a partialvacuum is created therein bycondensation of steam just beforerunning the purified oil in from anelevated tank. The required quantity ofunslaked lime, 2 to 4 per cent. of theweight of the fat, is run in with themolten fat, together with 30 per cent. to50 per cent. of water. While 8.7 percent. lime is theoretically required,practice has shown that 2 per cent. to 4per cent. is sufficient. The digestor,having been charged and adjusted,steam is turned on and a pressure of 8to 10 atmospheres maintained thereonfor a period of six to ten hours.

Samples of the fat are taken at variousintervals and the percentage of freefatty acids determined. When thesaponification is completed thecontents of the autoclave are removed,usually by blowing out the digestorinto a wooden settling tank, or by firstrunning off the glycerine water andthen blowing out the lime, soap andfatty acids. The mass discharged fromthe digestor separates into two layers,the upper consisting of a mixture oflime soap or "rock" and fatty acids, andthe lower layer contains the glycerineor "sweet" water. The glycerine wateris first run off through a clearing tankor oil separator, if this has not beendone directly from the autoclave, and

the mass remaining washed once ortwice more with water to remove anyglycerine still retained by the limesoap. The calculated amount of sulfuricacid to decompose the lime "rock" isthen added, and the mass agitated untilthe fatty acids contained therein areentirely set free. Another small wash isthen given and the wash water added tothe glycerine water already run off. Theglycerine water is neutralized withlime, filtered and concentrated as in theTwitchell process.

Due to the difficulties of working theautoclave saponification with lime,decomposing the large amount of limesoap obtained and dealing with muchgypsum formed thereby which collects

as a sediment and necessitates cleaningthe tanks, other substances are used toreplace lime. Magnesia, about 2 percent. of the weight of the fat, is usedand gives better results than lime. One-half to 1 per cent. of zinc oxide of theweight of the fat is even better adaptedand is now being extensively employedfor this purpose. In using zinc oxide itis possible to recover the zinc salts anduse them over again in the digestor,which makes the process as cheap towork as with lime, with far moresatisfactory results.

ACID SAPONIFICATION.

While it is possible to saponify fats and

oils in an autoclave with the addition ofacid to the fat, unless a specially-constructed digestor is built, the actionof the acid on the metal from which theautoclave is constructed prohibits itsuse. The acid saponification istherefore carried out by anothermethod.

The method of procedure for acidsaponification, therefore, is to firstpurify the fats with dilute acid asalready described. The purified, hot orwarm, dry fat is then run to a specially-built acidifier or a lead-lined tank andfrom 4 per cent. to 6 per cent. ofconcentrated sulfuric acid added to thefat, depending upon its character, thedegree of saponification required,

temperature and time of saponification.A temperature of 110 degrees C. ismaintained and the mass mixed fromfour to six hours. The tank is thenallowed to settle out the tar formedduring the saponification, and the fattyacids run off to another tank and boiledup about three times with one-third theamount of water. The water thusobtained contains the glycerine, andafter neutralization is concentrated.

AQUEOUSSAPONIFICATION.

While lime or a similar substance isordinarily used to aid in splitting fats

in an autoclave, the old water processis still used. This is a convenient,though slower and more dangerousmethod, of producing the hydrolysis ofthe glyceride, as well as the simplest inthat fatty acids and glycerine in a watersolution are obtained. The methodconsists in merely charging theautoclave with fats and adding about 30per cent. to 40 per cent. of their weightof water, depending on the amount offree fatty acid and subjecting thecharge to a pressure of 150 to 300pounds, until the splitting has takenplace. This is a much higher pressurethan when lime is used and therefore avery strong autoclave is required. Sincefatty acids and pure glycerine water are

obtained no subsequent treatment ofthe finished charge is necessary exceptseparating the glycerine water andgiving the fatty acids a wash with waterto remove all the glycerine from them.

SPLITTING FATS WITHFERMENTS.

In discussing the causes of rancidity ofoils and fats it was pointed out that theinitial splitting of these is due toenzymes, organized ferments. In theseeds of the castor oil plant, especiallyin the protoplasm of the seed, theenzyme which has the property ofcausing hydrolysis of the glycerides is

found. The ferment from the seeds ofthe castor oil plant is now extractedand used upon a commercial basis forsplitting fats.

The equipment necessary to carry outthis method of saponification is around, iron, lead-lined tank with aconical bottom, preferably about twiceas long as it is wide. Open and closedsteam coils are also necessary in thetank.

The oils are first heated and run intothis tank. The right temperature to heatthese to is about 1 degree to 2 degreesabove their solidification point. Forliquid oils 23 degrees C. is the properheat as under 20 degrees C. the

cleavage takes place slowly. Fatstitering 44 degrees C. or above must bebrought down in titer by mixing withthem oils of a lower titer as the fermentor enzyme is killed at about 45 degreesC. and thus loses its power of splitting.It is also necessary to have the fat inthe liquid state or the ferment does notact. The proper temperature must bemaintained with dry steam.

It is, of course, necessary to add water,which may be any kind desired,condensed, water from steam coils,well, city, etc. From 30 per cent. to 40per cent., on the average 35 per cent. ofwater is added, as the amountnecessary is regulated so as to notdilute the glycerine water

unnecessarily. To increase thehydrolysis a catalyzer, some neutralsalt, usually manganese sulfate isadded in the proportion of 0.15 percent. appears to vary directly as thesaponification number of the fat or oil.The approximate percentages offermentive substance to be added tovarious oils and fats follow:

Cocoanut oil 8%Palm Kernel oil 8%Cottonseed oil 6-7%Linseed oil 4-5%Tallow oil 8-10%

The oil, water, manganese sulfate andferment having been placed in the tankin the order named, the mixture isagitated with air for about a quarter ofan hour to form an even emulsion, inwhich state the mass is kept by stirringoccasionally with air while thesaponification is taking place. Atemperature is maintained a degree ortwo above the titer point of the fat withclosed steam which may be aided bycovering the tank for a period of 24 to

48 hours. The splitting takes placerapidly at first, then proceeds moreslowly. In 24 hours 80 per cent. of thefats are split and in 48 hours 85 percent. to 90 per cent.

When the cleavage has reached thedesired point the mass is heated to 80degrees-85 degrees C. with live orindirect steam while stirring with air.Then 0.1 per cent.-0.15 per cent ofconcentrated sulfuric acid diluted withwater is added to break the emulsion.When the emulsion is broken theglycerine water is allowed to settle outand drawn off. The glycerine watercontains 12 per cent. to 25 per cent.glycerine and contains manganesesulfate, sulfuric acid and albuminous

matter. Through neutralization withlime at boiling temperature andfiltration the impurities can almost allbe removed after which the glycerinewater may be fed to the evaporator.Should it be desired to overcome thetrouble due to the gypsum formed inthe glycerine, the lime treatment maybe combined with a previous treatmentof the glycerine water with bariumhydrate to remove the sulfuric acid,then later oxalic acid to precipitate thelime.

The fatty acids obtained by splittingwith ferments are of very good colorand adaptable for soap making.

KREBITZ PROCESS.

The Krebitz process which has beenused to some extent in Europe is basedupon the conversion of the fat or oilinto lime soap which is transformedinto the soda soap by the addition ofsodium carbonate. To carry out theprocess a convenient batch of, say,10,000 pounds of fat or oil, is run into ashallow kettle containing 1,200 to1,400 pounds of lime previously slakedwith 3,700 to 4,500 pounds of water.The mass is slowly heated with livesteam to almost boiling until anemulsion is obtained. The tank is thencovered and allowed to stand about 12hours. The lime soap thus formed is

dropped from the tank into the hopperof a mill, finely ground and conveyedto a leeching tank. The glycerine iswashed out and the glycerine water runto a tank for evaporation. The soap isthen further washed and these washingsare run to other tanks to be used overagain to wash a fresh batch of soap.About 150,000 pounds of water willwash the soap made from 10,000pounds of fat which makes between15,000 and 16,000 pounds of soap. Thefirst wash contains approximately 10per cent. glycerine and under ordinarycircumstances this only need beevaporated for glycerine recovery.

After extracting the glycerine the soapis slowly introduced into a boiling

solution of sodium carbonate or sodaash and boiled until the soda hasreplaced the lime. This is indicated bythe disappearance of the small lumpsof lime soap. Caustic soda is thenadded to saponify the fat not convertedby the lime saponification. The soap isthen salted out and allowed to settle outthe calcium carbonate. This drops tothe bottom of the kettle as a heavysludge entangling about 10 per cent. ofthe soap. A portion of this soap may berecovered by agitating the sludge withheat and water, pumping the soap offthe top and filtering the remainingsludge.

While the soap thus obtained is verygood, the percentage of glycerine

recovered is greatly increased and thecost of alkali as carbonate is less. Thedisadvantages are many. Largequantities of lime are required; it isdifficult to recover the soap from thelime sludge; the operations arenumerous prior to the soap makingproper and rather complicatedapparatus is required.

DISTILLATION OFFATTY ACIDS.

The fatty acids obtained by variousmethods of saponification may befurther improved by distillation.

In order to carry out this distillation,

two methods may be pursued, first, thecontinuous method, whereby the fattyacids are continually distilled for fiveto six days, and, second, the two phasemethod, whereby the distillationcontinues for 16 to 20 hours, afterwhich the residue is drawn off, treatedwith acid, and its distillate added to afresh charge of fatty acids. The lattermethod is by far the best, since theadvantages derived by thus proceedingmore than compensate the necessity ofcleaning the still. Better colored fattyacids are obtained; less unsaponifiablematter is contained therein; there is noaccumulation of impurities; the amountof neutral fat is lessened because thetreatment of the tar with acid causes a

cleavage of the neutral fat and thecandle tar or pitch obtained is harderand better and thus more valuable.

The stills are usually built of copper,which are heated by both direct fire andsuperheated steam. Distillation undervacuum is advisable. To begin thedistilling operation, the still is firstfilled with dry hot fatty acids to theproper level. Superheated steam is thenadmitted and the condenser is firstheated to prevent the freezing of thefatty acids, passing over into same.When the temperature reaches 230 deg.C. the distillation begins. At thebeginning, the fatty acids flow from thecondenser, an intense green color, dueto the formation of copper soaps

produced by the action of the fattyacids on the copper still. This colormay easily be removed by treating withdilute acid to decompose the coppersoaps.

In vacuum distillation, the operation isbegun without the use of vacuum.Vacuum is introduced only when thedistillation has proceeded for a timeand the introduction of this must becarefully regulated, else the rapidinfluence of vacuum will cause thecontents of the still to overflow. Whendistillation has begun a constant levelof fatty acids is retained therein byopening the feeding valve to same, andthe heat is so regulated as to producethe desired rate of distillation. As soon

as the distillate flows darker andslower, the feeding valve to the still isshut off and the distillation continueduntil most of the contents of the stillare distilled off, which is indicated by arise in the temperature. Distillation isthen discontinued, the still shut down,and in about an hour the contents aresufficiently cool to be emptied. Theresidue is run off into a properreceiving vessel, treated with diluteacid and used in the distillation of tar.

In the distillation of tar the samemethod as the above is followed, onlydistillation proceeds at a highertemperature. The first portion and lastportion of the distillate from tar are sodark that it is necessary to add them to

a fresh charge of fatty acids. By a wellconducted distillation of tar about 50per cent. of the fatty acids from the tarcan be used to mix with the distilledfatty acids. The residue of thisoperation called stearine pitch orcandle tar consists of a hard, brittle,dark substance. Elastic pitch onlyresults where distillation has been keptconstant for several days withoutinterrupting the process, and re-distilling the tar. In a good distillationthe distillation loss is 0.5 to 1.5% andloss in pitch 1.5%. Fatty acids whichare not acidified deliver about 3% ofpitch. Very impure fats yield even ahigher percentage in spite ofacidifying. For a long time it was found

impossible to find any use for stearinepitch, but in recent years a use has beenfound for same in the electricalinstallation of cables.

FOOTNOTES:

[12] Journ. Ind. Eng. Chem. (1909),I, p. 654.

CHAPTER VI

Analytical Methods.

While it is possible to attain a certainamount of efficiency in determiningthe worth of the raw material enteringinto the manufacture of soap throughorganoleptic methods, these are by nomeans accurate. It is, therefore,necessary to revert to chemicalmethods to correctly determine theselection of fats, oil or other substancesused in soap making, as well asstandardizing a particular soap

manufactured and to properly regulatethe glycerine recovered.

It is not our purpose to cover in detailthe numerous analytical processeswhich may be employed in theexamination of fats and oils, alkalis,soap and glycerine, as these are fullyand accurately covered in various texts,but rather to give briefly the necessarytests which ought to be carried out infactories where large amounts of soapare made. Occasion often arises whereit is impossible to employ a chemist,yet it is possible to have this work doneby a competent person or to havesomeone instruct himself as just how tocarry out the more simple analyses,which is not a very difficult matter.

The various standard solutionsnecessary to carrying out the simplertitrations can readily be purchasedfrom dealers in chemical apparatus andit does not take extraordinaryintelligence for anyone to operate aburette, yet in many soap plants in thiscountry absolutely no attention is paidto the examining of raw material,though many thousand pounds arehandled annually, which, if they weremore carefully examined would resultin the saving of much more money thanit costs to examine them or have themat least occasionally analyzed.

ANALYSIS OF FATS AND

OILS.

In order to arrive at proper results inthe analysis of a fat or oil, it isnecessary to have a proper sample. Toobtain this a sample of several of thepackages of oil or fat is taken and thesemixed or molten together into acomposite sample which is used inmaking the tests. If the oil or fat issolid, a tester is used in taking thesample from the package and if theyare liquid, it is a simple matter to drawoff a uniform sample from eachpackage and from these to form acomposite sample.

In purchasing an oil or fat for soap

making, the manufacturer is usuallyinterested in the amount of free fattyacid contained therein, of moisture, thetiter, the percentage of unsaponifiablematter and to previously determine thecolor of soap which will be obtainedwhere color is an object.

DETERMINATION OFFREE FATTY ACIDS.

Since the free fatty acid content of a fator oil represents a loss of glycerine, thegreater the percentage of free fattyacid, the less glycerine is contained inthe fat or oil, it is advisable to purchasea fat or oil with the lower free acid,

other properties and the price being thesame.

While the mean molecular weight ofthe mixed free fatty acids varies withthe same and different oils or fats andshould be determined for any particularanalysis for accuracy, the free fattyacid is usually expressed as oleic acid,which has a molecular weight of 282.

To carry out the analysis 5 to 20 gramsof the fat are weighed out into anErlenmeyer flask and 50 cubiccentimeters of carefully neutralizedalcohol are added. In order toneutralize the alcohol add a few dropsof phenolphthalein solution to sameand add a weak caustic soda solution

drop by drop until a very faint pinkcolor is obtained upon shaking orstirring the alcohol thoroughly. Themixture of fat and neutralized alcoholis then heated to boiling and titratedwith tenth normal alkali solution, usingphenolphthalein as an indicator. Asonly the free fatty acids are readilysoluble in the alcohol and the fat itselfonly slightly mixes with it, the flaskshould be well agitated toward the endof the titration. When a faint pink colorremains after thoroughly agitating theflask the end point is reached. In orderto calculate the percentage of free fattyacid as oleic acid, multiply the numberof cubic centimeters of tenth normalalkali used as read on the burette by

0.0282 and divide by the number ofgrams of fat taken for thedetermination and multiply by 100.

When dark colored oils or fats arebeing titrated it is often difficult toobtain a good end point withphenolphthalein. In such cases about 2cubic centimeters of a 2 per cent.alcoholic solution of Alkali Blue 6 B isrecommended.

Another method of directlydetermining the free fatty acid contentof tallow or grease upon which thisdetermination is most often made is toweigh out into an Erlenmeyer flaskexactly 5.645 grams of a sample oftallow or grease. Add about 75 cubic

centimeters of neutralized alcohol.Heat until it boils, then titrate withtenth normal alkali and divide thereading by 2, which gives thepercentage of free fatty acid as oleic. Ifa fifth normal caustic solution is used,the reading on the burette gives thepercentage of free fatty acid directly.This method, while it eliminates thenecessity of calculation, is troublesomein that it is difficult to obtain the exactweight of fat.

MOISTURE.

To calculate the amount of moisturecontained in a fat or oil 5 to 10 gramsare weighed into a flat bottom dish,

together with a known amount of clean,dry sand, if it is so desired. The dish isthen heated over a water bath, or at atemperature of 100-110 degs. C., untilit no longer loses weight upon dryingand reweighing the dish. One hourshould elapse between the time the dishis put on the water bath and the time itis taken off to reweigh. The differencebetween the weight of the dish is put onthe water bath and the time it is takenoff when it reaches a constant weight ismoisture. This difference divided bythe original weight of the fat or oil ×100 gives the percentage of moisture.

When highly unsaturated fats or oilsare being analyzed for moisture, anerror may be introduced either by the

absorption of oxygen, which isaccelerated at higher temperature, orby the formation of volatile fatty acids.The former causes an increase inweight, the latter causes a decrease. Toobviate this, the above operation ofdrying should be carried out in thepresence of some inert gas likehydrogen, carbon dioxide, or nitrogen.

TITER.

The titer of a fat or oil is really anindication of the amount of stearic acidcontained therein. The titer, expressedin degrees Centigrade, is thesolidification point of the fatty acids ofan oil or fat. In order to carry out the

operation a Centigrade thermometergraduated in one or two-tenths of adegree is necessary. A thermometergraduated between 10 degs. centigradeto 60 degs. centigrade is best adaptedand the graduations should be clear cutand distinct.

To make the determination about 30grams of fat are roughly weighed in ametal dish and 30-40 cubic centimetersof a 30 per cent. (36 degs. Baumé)solution of sodium hydroxide, togetherwith 30-40 cubic centimeters ofalcohol, denatured alcohol will do, areadded and the mass heated untilsaponified. Heat over a low flame orover an asbestos plate until the soapthus formed is dry, constantly stirring

the contents of the dish to preventburning. The dried soap is thendissolved in about 1000 cubiccentimeters of water, being certain thatall the alcohol has been expelled byboiling the soap solution for about halfan hour. When the soap is in solutionadd sufficient sulphuric acid todecompose the soap, approximately100 cubic centimeters of 25 degs.Baumé sulphuric acid, and boil untilthe fatty acids form a clear layer on topof the liquid. A few pieces of pumicestone put into the mixture will preventthe bumping caused by boiling. Siphonoff the water from the bottom of thedish and wash the fatty acids withboiling water until free from sulphuric

acid. Collect the fatty acids in a smallcasserole or beaker and dry them over asteam bath or drying oven at 110 degs.Centigrade. When the fatty acids aredry, cool them to about 10 degs. abovethe titer expected and transfer them toa titer tube or short test tube which isfirmly supported by a cork in theopening of a salt mouth bottle. Hangthe thermometer by a cord from abovethe supported tube so it reaches closeto the bottom when in the titer tubecontaining the fatty acids and so that itmay be used as a stirrer. Stir the massrather slowly, closely noting thetemperature. The temperature willgradually fall during the stirringoperation and finally remain stationary

for half a minute or so then rise from0.1 to 0.5 degs. The highest point towhich the mercury rises after havingbeen stationary is taken as the readingof the titer.

DETERMINATION OFUNSAPONIFIABLE

MATTER.

In order to determine theunsaponifiable matter in fats and oilsthey are first saponified, then theunsaponifiable, which consists mainlyof hydrocarbons and the higheralcohols cholesterol or phytosterol, isextracted with ether or petroleum ether,

the ether evaporated and the residueweighed as unsaponifiable.

To carry out the process first saponifyabout 5 grams of fat or oil with anexcess of alcoholic potassium hydrate,20-30 cubic centimeters of a 1 to 10solution of potassium hydroxide inalcohol until the alcohol is evaporatedover a steam bath. Wash the soap thusformed into a separatory funnel of 200cubic centimeters capacity with 80-100cubic centimeters water. Then addabout 60 cubic centimeters of ether,petroleum ether or 86 degs. gasolineand thoroughly shake the funnel toextract the unsaponifiable. Should thetwo layers not separate readily, add afew cubic centimeters of alcohol,

which will readily cause them toseparate. Draw off the watery solutionfrom beneath and wash the ether withwater containing a few drops of sodiumhydrate and run to another dish. Pourthe watery solution into the funnelagain and repeat the extraction once ortwice more or until the ether shows nodiscoloration. Combine the etherextractions into the funnel and washwith water until no alkaline reaction isobtained from the wash water. Run theether extract to a weighed dish,evaporate and dry rapidly in a dryingoven. As some of the hydrocarbons arereadily volatile at 100 degs.Centigrade, the drying should not becarried on any longer than necessary.

The residue is then weighed and theoriginal weight of fat taken dividedinto the weight of the residue × 100gives the percentage unsaponifiable.

TEST FOR COLOR OFSOAP.

It is often desirable to determine thecolor of the finished soap by a rapiddetermination before it is made intosoap. It often happens, especially withthe tallows, that a dark colored sampleproduces a light colored soap, whereasa bleached light colored tallowproduces a soap off shade.

To rapidly determine whether the color

easily washes out of the tallow withlye, 100 cubic centimeters of tallow aresaponified in an enameled or iron dishwith 100 cubic centimeters of 21 degs.Baumé soda lye and 100 cubiccentimeters of denatured alcohol.Continue heating over a wire gauzeuntil all the alcohol is expelled andthen add 50 cubic centimeters of the 21degs. Baumé lye to grain the soap.Allow the lyes to settle and with aninverted pipette draw off the lyes into atest tube or bottle. Close the soap with100 cubic centimeters of hot water andwhen closed again grain with 50 cubiccentimeters of the lye by just bringingto a boil over an open flame. Againallow the lyes to settle and put aside a

sample of the lye for comparison.Repeat the process of closing, grainingand settling and take a sample of lye. Ifthe lye is still discolored repeat theabove operations again or until the lyeis colorless. Ordinarily all the colorwill come out with the third lye. Thesoap thus obtained containsconsiderable water which makes itappear white. The soap is, therefore,dried to about 15 per cent. moistureand examined for color. The color thusobtained is a very good criterion as towhat may be expected in the soapkettle.

By making the above analyses of fatsor oils the main properties as to theiradaptability for being made into soap

are determined. In some cases,especially where adulteration ormixtures of oils are suspected, it isnecessary to further analyze same. Themethods of carrying out these analysesare fully covered by various texts onfats and oils and we will not go intodetails regarding the method ofprocedure in carrying these out.

TESTING OF ALKALISUSED IN SOAP MAKING.

The alkalis entering into themanufacture of soap such as causticsoda or sodium hydroxide, causticpotash or potassium hydrate, carbonate

of soda or sodium carbonate, carbonateof potash or potassium carbonateusually contain impurities which do notenter into combination with the fats orfatty acids to form soap. It is out of thequestion to use chemically pure alkalisin soap making, hence it is oftennecessary to determine the alkalinity ofan alkali. It may again be pointed outthat in saponifying a neutral fat or oilonly caustic soda or potash areefficient and the carbonate contained inthese only combines to a more or lessextent with any free fatty acidscontained in the oils or fats. Causticsoda or potash or lyes made from thesealkalis upon exposure to the air aregradually converted into sodium or

potassium carbonate by the action ofthe carbon dioxide contained in the air.While the amount of carbonate thusformed is not very great and is greatestupon the surface, all lyes as well ascaustic alkalis contain some carbonate.This carbonate introduces an error inthe analysis of caustic alkalis whenaccuracy is required and thus in theanalysis of caustic soda or potash it isnecessary to remove the carbonatewhen the true alkalinity as sodiumhydroxide or potassium hydroxide isdesired. This may be done by titrationin alcohol which has been neutralized.

In order to determine the alkalinity ofany of the above mentioned alkalis, itis first necessary to obtain a

representative sample of the substanceto be analyzed. To do this take smallsamples from various portions of thepackage and combine them into acomposite sample. Caustic potash andsoda are hygroscopic and samplesshould be weighed at once or kept in awell stoppered bottle. Sodium orpotassium carbonate can be weighedmore easily as they do not rapidlyabsorb moisture from the air.

To weigh the caustic soda or potashplace about five grams on a watch glasson a balance and weigh as rapidly aspossible. Wash into a 500 cubiccentimeter volumetric flask and bringto the mark with distilled water. Pipetteoff 50 cubic centimeters into a 200

cubic centimeter beaker, dilute slightlywith distilled water, add a few drops ofmethyl orange indicator and titratewith normal acid. For the carbonatesabout 1 gram may be weighed, washedinto a 400 cubic centimeter beaker,diluted with distilled water, methylorange indicator added and titratedwith normal acid. It is advisable to usemethyl orange indicator in thesetitrations as phenolphthalein is affectedby the carbon dioxide generated whenan acid reacts with a carbonate anddoes not give the proper end point,unless the solution is boiled to expelthe carbon dioxide. Litmus may also beused as the indicator, but here again itis necessary to boil as carbon dioxide

also affects this substance. As an aid tothe action of these common indicatorsthe following table may be helpful:

Indicator.Color inAcidSolution.

Color inAlkalineSolution.

Actionof CO

Methyl orange Red YellowVeryslightlyacid

Phenolphthalein Colorless Red AcidLitmus Red Blue Acid

It may be further stated that methylorange at the neutral point is orange incolor.

To calculate the percentage of effective

alkali from the above titrations, it mustbe first pointed out that in the case ofcaustic potash or soda aliquot portionsare taken. This is done to reduce theerror necessarily involved by weighing,as the absorption of water is decided.Thus we had, say, exactly 5 gramswhich weighed 5.05 grams by the timeit was balanced. This was dissolved in500 cubic centimeters of water and 50cubic centimeters or one tenth of theamount of the solution was taken, or ineach 50 cubic centimeters there were0.505 grams of the sample. We thusreduced the error of weighing by onetenth provided other conditionsintroduce no error. In the case of thecarbonates the weight is taken directly.

One cubic centimeter of a normal acidsolution is the equivalent of:

Grams.Sodium Carbonate, Na2CO3 0.05305Sodium Hydroxide, NaOH 0.04006Sodium Oxide, Na2O 0.02905Carbonate K2CO3 0.06908Potassium Hydroxide, KOH 0.05616Potassium Oxide, K2O 0.04715

Hence to arrive at the alkalinity wemultiply the number of cubiccentimeters, read on the burette, by thefactor opposite the terms in which wedesire to express the alkalinity, dividethe weight in grams thus obtained by

the original weight taken, and multiplythe result by 100, which gives thepercentage of alkali in the properterms. For example, say, we took the0.505 grams of caustic potash asexplained above and required 8.7 cubiccentimeter normal acid to neutralizethe solution, then

8.7 × .05616 = .4886 grams KOHin sample

.4886 ----- × 100 = 96.73% KOH insample. .505

Caustic potash often contains somecaustic soda, and while it is possible to

express the results in terms of KOH,regardless of any trouble that may becaused by this mixture in soap making,an error is introduced in the results, notall the alkali being caustic potash. Insuch cases it is advisable to consult abook on analysis as the analysis is farmore complicated than those given wewill not consider it. The presence ofcarbonates, as already stated, alsocauses an error. To overcome this thealkali is titrated in absolute alcohol,filtering off the insoluble carbonate.The soluble portion is caustic hydrateand may be titrated as such. Thecarbonate remaining on the filter paperis dissolved in water and titrated ascarbonate.

SOAP ANALYSIS.

To obtain a sample of a cake of soapfor analysis is a rather difficult matteras the moisture content of the outer andinner layer varies considerably. Toovercome this difficulty a borer orsampler may be run right through thecake of soap, or slices may be cut fromvarious parts of the cake, or the cakemay be cut and run through a meatchopper several times and mixed. Asufficient amount of a homogeneoussample obtained by any of thesemethods is preserved for the entireanalysis by keeping the soap in asecurely stoppered bottle.

The more important determinations ofsoap are moisture, free alkali, or fattyacid, combined alkali and total fattymatter. Besides these it is oftennecessary to determine insolublematter, glycerine, unsaponifiablematter, rosin and sugar.

MOISTURE.

The analysis of soap for moisture, at itsbest, is most unsatisfactory, for byheating it is impossible to drive off allthe water, and on the other handvolatile oils driven off by heat are apart of the loss represented asmoisture.

The usual method of determiningmoisture is to weigh 2 to 3 grams offinely shaved soap on a watch glass andheat in an oven at 105 degrees C. for 2to 3 hours. The loss in weight isrepresented as water, although it isreally impossible to drive off all thewater in this way.

To overcome the difficulties justmentioned either the Smith or Fahrionmethod may be used. Allenrecommends Smith's method which issaid to be truthful to within 0.25 percent. Fahrion's method, according tothe author, gives reliable results towithin 0.5 per cent. Both are morerapid than the above manipulation. Tocarry out the method of Smith, 5 to 10

grams of finely ground soap are heatedover a sand bath with a small Bunsenflame beneath it, in a large porcelaincrucible. The heating takes 20 to 30minutes, or until no further evidence ispresent of water being driven off. Thismay be tested by the fogging of a coldpiece of glass held over the crucibleimmediately upon removing theburner. When no fog appears the soapis considered dry. Any lumps of soapmay be broken up by a small glass rod,weighed with the crucible, and with aroughened end to more easily separatethe lumps. Should the soap burn, thiscan readily be detected by the odor,which, of course, renders the analysisuseless. The loss in weight is moisture.

By Fahrion's method[13], 2 to 4 gramsof soap are weighed in a platinumcrucible and about three times itsweight of oleic acid, which has beenheated at 120 degrees C. until all thewater is driven off and preserved frommoisture, is added and reweighed. Thedish is then cautiously heated with asmall flame until all the water is drivenoff and all the soap is dissolved. Caremust be exercised not to heat toohighly or the oleic acid willdecompose. The moment the water isall driven off a clear solution isformed, provided no fillers are presentin the soap. The dish is then cooled in adessicator and reweighed. The loss inweight of acid plus soap is moisture

and is calculated on the weight of soaptaken. This determination takes aboutfifteen minutes.

FREE ALKALI OR ACID.

(a) Alcoholic Method.

Test a freshly cut surface of the soapwith a few drops of an alcoholicphenolphthalein solution. If it does notturn red it may be assumed free fat ispresent; should a red color appear, freealkali is present. In any case dissolve 2to 5 grams of soap in 100 cubiccentimeters of neutralized alcohol andheat to boiling until in solution. Filteroff the undissolved portion containing

carbonate, etc., and wash with alcohol.Add phenolphthalein to the filtrate andtitrate with N/10 acid and calculate theper cent. of free alkali as sodium orpotassium hydroxide. Should thefiltrate be acid instead of alkaline,titrate with N/10 alkali and calculatethe percentage of free fatty acid asoleic acid.

The insoluble portion remaining on thefilter paper is washed with water untilall the carbonate is dissolved. Thewashings are then titrated with N/10sulfuric acid and expressed as sodiumor potassium carbonate. Should boratesor silicates be present it is possible toexpress in terms of these. If borax ispresent the carbon dioxide is boiled off

after neutralizing exactly to methylorange; cool, add mannite andphenolphthalein and titrate the boricacid with standard alkali.

(b) Bosshard and HuggenbergMethod.[14]

In using the alcoholic method for thedetermination of the free alkali or fatin soap there is a possibility of bothfree fat and free alkali being present.Upon boiling in an alcoholic solutionthe fat will be saponified, thusintroducing an error in the analysis.The method of Bosshard andHuggenberg overcomes this objection.Their method is briefly as follows:

Reagents.

1. N/10 hydrochloric acid tostandardize N/10 alcoholic sodiumhydroxide.

2. Approximately N/10 alcoholicsodium hydroxide to fix and control theN/40 stearic acid.

3. N/40 stearic acid. Preparation: About7.1 grams of stearic acid are dissolvedin one liter of absolute alcohol, thesolution filtered, the strengthdetermined by titration against N/10NaOH and then protected in a wellstoppered bottle, or better stillconnected directly to the burette.

4. A 10 per cent. solution of bariumchloride. Preparation: 100 grams ofbarium chloride are dissolved in oneliter of distilled water and filtered. Theneutrality of the solution should beproven as it must be neutral.

5. α naphtholphthalein indicatoraccording to Sorenson. Preparation: 0.1gram of α naphtholphthalein isdissolved in 150 cubic centimeters ofalcohol and 100 cubic centimeters ofwater. For every 10 cubic centimetersof liquid use at least 12 drops ofindicator.

6. Phenolphthalein solution 1 gram to100 cubic centimeter 96 per cent.alcohol.

7. Solvent, 50 per cent. alcoholneutralized.

MANIPULATION.

First—Determine the strength of theN/10 alcoholic sodium hydroxide interms of N/10 hydrochloric acid andcalculate the factor, e. g.:

10 c.c. N/10alcoholic NaOH

= 9.95 N/10HCl}

9.9610 c.c. N/10alcoholic NaOH

= 9.96 N/10HCl}

The alcoholic N/10 NaOH has a factorof 0.996.

Second—Control the N/40 stearic acid

with the above alkali to obtain itsfactor, e. g.:

40 c.c. N/40alcoholic stearicacid =

10.18 c.c.N/10 NaOH} }

10.240 c.c. N/40alcoholic stearicacid =

10.22 c.c.N/10 NaOH}

10.2 × F N/10 NaOH (0.996) = FactorN/40 stearic acid

∴Factor N/40 stearic acid = 1.016.

Third—About 5 grams of soap areweighed and dissolved in 100 cubiccentimeters of 50 per cent. neutralizedalcohol in a 250 cubic centimeter

Erlenmeyer flask over a water bath andconnected with a reflux condensor.When completely dissolved, whichtakes but a few moments, it is cooledby allowing a stream of running waterto run over the outside of the flask.

Fourth—The soap is precipitated with15 to 20 cubic centimeters of the 10 percent. barium chloride solution.

Fifth—After the addition of 2 to 5cubic centimeters of αnaphtholphthalein solution the solutionis titrated with N/40 alcoholic stearicacid. α naphtholphthalein is red with anexcess of stearic acid. To mark thecolor changes it is advisable to first runa few blanks until the eye has become

accustomed to the change in theindicator in the same way. The changefrom green to red can then be carefullyobserved.

Let us presume 5 grams of soap weretaken for the analysis and 20 cubiccentimeters of N/40 stearic acid wererequired for the titration then tocalculate the amount of NaOH sincethe stearic factor is 1.016.

20 × 1.016 = 20.32 N/40 stearic acidreally required.

1 cubic centimeter N/40 stearic acid =0.02 per cent. NaOH for 5 grams soap.

Δ 20.32 cubic centimeters N/40 stearicacid = 0.02 × 20.32 per cent. NaOH for

5 grams soap.

Hence the soap contains 0.4064 percent. NaOH.

It is necessary, however, to make acorrection by this method. When thefree alkali amounts to over 0.1 percent. the correction is + 0.01, and whenthe free alkali exceeds 0.4 per cent. thecorrection is + 0.04, hence in the abovecase we multiply 0.004064 by 0.04, addthis amount to 0.004064 and multiplyby 100 to obtain the true percentage.Should the alkalinity have been near0.1 per cent. we would have multipliedby 0.01 and added this.

If carbonate is also present in the soap,

another 5 grams of soap is dissolved in100 cubic centimeters of 50 per cent.alcohol and the solution titrateddirectly after cooling with N/40 stearicacid, using α naphtholphthalein orphenolphthalein as an indicator,without the addition of bariumchloride. From the difference of thetwo titrations the alkali present ascarbonate is determined.

If the decomposed soap solution iscolorless with phenolphthalein, freefatty acids are present, which may bequickly determined with alcoholicN/10 sodium hydroxide.

INSOLUBLE MATTER.

The insoluble matter in soap mayconsist of organic or inorganicsubstances. Among the organicsubstances which are usually present insoap are oat meal, bran, sawdust, etc.,while among the common inorganic ormineral compounds are pumice, silex,clay, talc, zinc oxide, infusorial earth,sand or other material used as fillers.

To determine insoluble matter, 5 gramsof soap are dissolved in 75 cubiccentimeters of hot water. The solutionis filtered through a weighed goochcrucible or filter paper. The residueremaining on the filter is washed withhot water until all the soap is removed,is then dried to constant weight at 105degrees C. and weighed. From the

difference in weight of the gooch orfilter paper and the dried residueremaining thereon after filtering anddrying, the total percentage ofinsoluble matter may easily becalculated. By igniting the residue andreweighing the amount of insolublemineral matter can be readilydetermined.

STARCH AND GELATINE.

Should starch or gelatine be present insoap it is necessary to extract 5 gramsof the soap with 100 cubic centimetersof 95 per cent. neutralized alcohol in aSoxhlet extractor until the residue onthe extraction thimble is in a powder

form. If necessary the apparatus shouldbe disconnected and any lumpscrushed, as these may contain soap.The residue remaining on the thimbleconsists of all substances present insoap, insoluble in alcohol. This is driedand weighed so that any percentage ofimpurities not actually determined canbe found by difference. Starch andgelatine are separated from carbonate,sulfate and borate by dissolving thelatter out through a filter with coldwater. The starch and gelatine thusremaining can be determined by knownmethods, starch by the method of directhydrolysis[15] and gelatine byKjeldahling and calculating thecorresponding amount of gelatine from

the percentage of nitrogen (17.9%)therein.[16]

TOTAL FATTY ANDRESIN ACIDS.

To the filtrate from the insolublematter add 40 cubic centimeters of halfnormal sulfuric acid, all the acid beingadded at once. Boil, stir thoroughly forsome minutes and keep warm on awater bath until the fatty acids havecollected as a clear layer on thesurface. Cool by placing the beaker inice and syphon off the acid waterthrough a filter. Should the fatty acidsnot readily congeal a weighed amount

of dried bleached bees-wax or stearicacid may be added to the hot mixture.This fuses with the hot mass and formsa firm cake of fatty acids upon cooling.Without removing the fatty acids fromthe beaker, add about 300 cubiccentimeters of hot water, cool, syphonoff the water through the same filterused before and wash again. Repeatwashing, cooling and syphoningprocesses until the wash water is nolonger acid. When this stage is reached,dissolve any fatty acid which may haveremained on the filter with hot 95 percent. alcohol into the beaker containingthe fatty acids. Evaporate the alcoholand dry the beaker to constant weightover a water bath. The fatty acids thus

obtained represent the combined fattyacids, uncombined fat andhydrocarbons.

DETERMINATION OFROSIN.

If resin acids are present, this may bedetermined by the Liebermann-Storchreaction. To carry out this test shake 2cubic centimeters of the fatty acidswith 5 cubic centimeters of aceticanhydride; warm slightly; cool; drawoff the anhydride and add 1:1 sulfuricacid. A violet color, which is notpermanent, indicates the presence ofrosin in the soap. The cholesterol in

linseed or fish oil, which of course maybe present in the soap, also give thisreaction.

Should resin acids be present, thesemay be separated by the Twitchellmethod, which depends upon thedifference in the behavior of the fattyand resin acids when converted intotheir ethyl esters through the action ofhydrochloric acid. This may be carriedout as follows:

Three grams of the dried mixed acidsare dissolved in 25 cubic centimetersof absolute alcohol in a 100 cubiccentimeter stoppered flask; the flaskplaced in cold water and shaken. Tothis cooled solution 25 cubic

centimeters of absolute alcoholsaturated with dry hydrochloric acid isadded. The flask is shaken occasionallyand the action allowed to continue fortwenty minutes, then 10 grams of drygranular zinc chloride are added, theflask shaken and again allowed to standfor twenty minutes. The contents of theflask are then poured into 200 cubiccentimeters of water in a 500 cubiccentimeter beaker and the flask rinsedout with alcohol. A small strip of zincis placed in the beaker and the alcoholevaporated. The beaker is then cooledand transferred to a separatory funnel,washing out the beaker with 50 cubiccentimeters of gasoline (boiling below80 degrees C.) and extracting by

shaking the funnel well. Draw off theacid solution after allowing to separateand wash the gasoline with water untilfree from hydrochloric acid. Draw offthe gasoline solution and evaporate thegasoline. Dissolve the residue inneutral alcohol and titrate withstandard alkali using phenolphthaleinas an indicator. One cubic centimeterof normal alkali equals 0.346 grams ofrosin. The rosin may be gravimetricallydetermined by washing the gasolineextract with water, it not beingnecessary to wash absolutely free fromacid, then adding 0.5 gram ofpotassium hydroxide and 5 cubiccentimeters of alcohol in 50 cubiccentimeters of water. Upon shaking the

resin acids are rapidly saponified andextracted by the dilute alkaline solutionas rosin soaps, while the ethyl estersremain in solution in the gasoline.Draw off the soap solution, wash thegasoline solution again with dilutealkali and unite the alkaline solutions.Decompose the alkaline soap solutionwith an excess of hydrochloric acid andweigh the resin acids liberated as in thedetermination of total fatty acids.

According to Lewkowitsch, the resultsobtained by the volumetric methodwhich assumes a combining weight of346 for resin acids, are very likely tobe high. On the other hand thoseobtained by the gravimetric method aretoo low.

Leiste and Stiepel[17] have devised asimpler method for the determinationof rosin. They make use of the fact thatthe resin acids as sodium soaps aresoluble in acetone and particularlyacetone containing two per cent. water,while the fatty acid soaps are soluble inthis solvent to the extent of only about2 per cent. First of all it is necessary toshow that the sample to be analyzedcontains a mixture of resin and fattyacids. This may be done by theLiebermann-Storch reaction alreadydescribed. Glycerine interferes with themethod. Two grams of fatty acids or 3grams of soap are weighed in a nickelcrucible and dissolved in 15-20 cubiccentimeters of alcohol. The solution is

then neutralized with alcoholic sodiumhydroxide, using phenolphthalein as anindicator. The mass is concentrated byheat over an asbestos plate until aslight film forms over it. Then about 10grams of sharp, granular, ignited sandare stirred in by means of a spatula, thealcohol further evaporated, the mixturebeing constantly stirred and thenthoroughly dried in a drying oven. Thesolvent for the cooled mass is acetonecontaining 2 per cent. water. It isobtained from acetone dried by ignitedsodium sulfate and adding 2 per cent.water by volume. One hundred cubiccentimeters of this solvent aresufficient for extracting the above. Theextraction of the rosin soap is

conducted by adding 10 cubiccentimeters of acetone eight times,rubbing the mass thoroughly with aspatula and decanting. The decantedportions are combined in a beaker andthe suspended fatty soaps allowed toseparate. The mixture is then filteredinto a previously weighed flask andwashed several times with the acetoneremaining. The solution of rosin soapshould show no separation of solidmatter after having evaporated to halfthe volume and allowing to cool. If aseparation should occur anotherfiltration and the slightest possiblewashing is necessary. To complete theanalysis, the acetone is completelyevaporated and the mass dried to

constant weight in a drying oven. Theweight found gives the weight of therosin soap. In conducting thedetermination, it is important to dry themixture of soap and sand thoroughly.In dealing with potash soaps it isnecessary to separate the fatty acidsfrom these and use them as acetonedissolves too great a quantity of apotash soap.

TOTAL ALKALI.

In the filtrate remaining after havingwashed the fatty acids in thedetermination of total fatty and resinacids all the alkali present as soap, ascarbonate and as hydroxide remains in

solution as sulfate. Upon titrating thissolution with half normal alkali thedifference between the half normalacid used in decomposing the soap andalkali used in titrating the excess ofacid gives the amount of total alkali inthe soap. By deducting the amount offree alkali present as carbonate orhydroxide previously found the amountof combined alkali in the soap may becalculated.

To quickly determine total alkali insoap a weighed portion of the soap maybe ignited to a white ash and the ashtitrated for alkalinity using methylorange as an indicator.

UNSAPONIFIEDMATTER.

Dissolve 5 grams of soap in 50 cubiccentimeters of 50 per cent. alcohol.Should any free fatty acids be presentneutralize them with standard alkali.Wash into a separatory funnel with 50per cent. alcohol and extract with 100cubic centimeters of gasoline, boilingat 50 degrees to 60 degrees C. Washthe gasoline with water, draw off thewatery layer. Run the gasoline into aweighed dish, evaporate the alcohol,dry and weigh the residue asunsaponified matter. The residuecontains any hydrocarbon oils or fats

not converted into soap.

SILICA AND SILICATES.

The insoluble silicates, sand, etc., arepresent in the ignited residue in thedetermination of insoluble matter.Sodium silicate, extensively used as afiller, however, will only show itself informing a pasty liquid. Where it isdesired to determine sodium silicate,10 grams of soap are ashed by ignition,hydrochloric acid added to the ash inexcess and evaporated to dryness. Morehydrochloric acid is then added and themass is again evaporated until dry;then cooled; moistened withhydrochloric acid; dissolved in water;

filtered; washed; the filtrate evaporatedto dryness and again taken up withhydrochloric acid and water; filteredand washed. The precipitates are thencombined and ignited. Silicon dioxide(SiO2) is thus formed, which can becalculated to sodium silicate(Na2Si4O9). Should other metals thanalkali metals be suspected present thefiltrate from the silica determinationsshould be examined.

GLYCERINE IN SOAP.

To determine the amount of glycerinecontained in soap dissolve 25 grams inhot water, add a slight excess of

sulfuric acid and keep hot until thefatty acids form as a clear layer on top.Cool the mass and remove the fattyacids. Filter the acid solution into a 25cubic centimeter graduated flask; bringto the mark with water and determinethe glycerine by the bichromatemethod as described under glycerineanalysis.

When sugar is present the bichromatewould be reduced by the sugar, hencethis method is not applicable. In thiscase remove the fatty acids as before,neutralize an aliquot portion with milkof lime, evaporate to 10 cubiccentimeters, add 2 grams of sand andmilk of lime containing about 2 gramsof calcium hydroxide and evaporate

almost to dryness. Treat the moistresidue with 5 cubic centimeters of 96per cent. alcohol, rub the whole massinto a paste, then constantly stirring,heat on a water bath and decant into a250 cubic centimeter graduated flask.Repeat the washing with 5 cubiccentimeters of alcohol five or sixtimes, each time pouring the washingsinto the flask; cool the flask to roomtemperature and fill to the mark with96 per cent. alcohol, agitate the flaskuntil well mixed and filter through adry filter paper. Take 200 cubiccentimeters of the nitrate and evaporateto a syrupy consistency over a safetywater bath. Wash the liquor into astoppered flask with 20 cubic

centimeters of absolute alcohol, add 30cubic centimeters of absolute ether 10cubic centimeters at a time, shakingwell after each addition and let standuntil clear. Pour off the solutionthrough a filter into a weighed dish andwash out the flask with a mixture ofthree parts absolute ether and two partsabsolute alcohol. Evaporate to a syrup,dry for one hour at the temperature ofboiling water, weigh, ignite and weighagain. The loss is glycerine. Thismultiplied by 5/4 gives the total lossfor the aliquot portion taken. Theglycerine may also be determined bythe acetin or bichromate methods afterdriving off the alcohol and ether if sodesired.

SUGAR IN SOAP.

To determine sugar in soap, usuallypresent in transparent soaps,decompose a soap solution of 5 gramsof soap dissolved in 100 cubiccentimeters of hot water with an excessof hydrochloric acid and separate thefatty acids as usual. Filter the acidsolution into a graduated flask andmake up to the mark. Take an aliquotcontaining approximately 1 per cent. ofreducing sugar and determine theamount of sugar by the Soxhletmethod.[18]

GLYCERINE ANALYSIS.

The methods of analyzing glycerinevaried so greatly due to the fact thatglycerine contained impurities whichacted so much like glycerine as tointroduce serious errors in thedeterminations of crude glycerine. Thisled to the appointment of committeesin the United States and Europe toinvestigate the methods of glycerineanalysis. An international committeemet after their investigations anddecided the acetin method shouldcontrol the buying and selling ofglycerine, but the more convenientbichromate method in a standardizedform might be used in factory controland other technical purposes. Thefollowing are the methods of analysis

and sampling as suggested by theinternational committee:

SAMPLING.

The most satisfactory method availablefor sampling crude glycerine liable tocontain suspended matter, or which isliable to deposit salt on settling, is tohave the glycerine sampled by amutually approved sampler as soon aspossible after it is filled into drums,but in any case before any separation ofsalt has taken place. In such cases heshall sample with a sectional sampler(see appendix) then seal the drums,brand them with a number foridentification, and keep a record of the

brand number. The presence of anyvisible salt or other suspended matteris to be noted by the sampler, and areport of the same made in hiscertificate, together with thetemperature of the glycerine. Eachdrum must be sampled. Glycerinewhich has deposited salt or other solidmatter cannot be accurately sampledfrom the drums, but an approximatesample can be obtained by means ofthe sectional sampler, which will allowa complete vertical section of theglycerine to be taken including anydeposit.

ANALYSIS.

1 . Determination of Free CausticAlkali.—Put 20 grams of the sampleinto a 100 cc. flask, dilute withapproximately 50 cc. of freshly boileddistilled water, add an excess of neutralbarium chloride solution, 1 cc. ofphenolphthalein solution, make up tothe mark and mix. Allow theprecipitate to settle, draw off 50 cc. ofthe clear liquid and titrate with normalacid (N/1). Calculate the percentage ofNa2O existing as caustic alkali.

2 . Determination of Ash and TotalAlkalinity.—Weigh 2 to 5 grams of thesample in a platinum dish, burn off theglycerine over a luminous Argandburner or other source of heat,[19]

giving a low temperature, to avoidvolatilization and the formation ofsulphides. When the mass is charred tothe point that water will not be coloredby soluble organic matter, lixiviatewith hot distilled water, filter, washand ignite the residue in the platinumdish. Return the filtrate and washingsto the dish, evaporate the water, andcarefully ignite without fusion. Weighthe ash.

Dissolve the ash in distilled water andtitrate total alkalinity, using asindicator methyl orange cold or litmusboiling.

3 . Determination of Alkali Present asCarbonate.—Take 10 grams of the

sample, dilute with 50 cc. distilledwater, add sufficient N/1 acid toneutralize the total alkali found at (2),boil under a reflux condenser for 15 to20 minutes, wash down the condensertube with distilled water, free fromcarbon dioxide, and then titrate backwith N/1 NaOH, using phenolphthaleinas indicator. Calculate the percentageof Na2O. Deduct the Na2O found in (1).The difference is the percentage ofNa2O existing as carbonate.

4 . Alkali Combined with OrganicAcids.—The sum of the percentages ofNa2O found at (1) and (3) deductedfrom the percentage found at (2) is ameasure of the Na2O or other alkali

combined with organic acids.

5 . Determination of Acidity.—Take 10grams of the sample, dilute with 50 cc.distilled water free from carbondioxide, and titrate with N/1 NaOH andphenolphthalein. Express in terms ofNa2O required to neutralize 100 grams.

6 . Determination of Total Residue at160° C.—For this determination thecrude glycerine should be slightlyalkaline with Na2CO3 not exceeding0.2 per cent. Na2O, in order to preventloss of organic acids. To avoid theformation of polyglycerols thisalkalinity must not be exceeded.

Ten grams of the sample are put into a

100 cc. flask, diluted with water andthe calculated quantity of N/1 HCl orNa2CO3 added to give the requireddegree of alkalinity. The flask is filledto 100 cc., the contents mixed, and 10cc. measured into a weighed Petrie orsimilar dish 2.5 in. in diameter and 0.5in. deep, which should have a flatbottom. In the case of crude glycerineabnormally high in organic residue asmaller amount should be taken, so thatthe weight of the organic residue doesnot materially exceed 30 to 40milligrams.

The dish is placed on a water bath (thetop of the 160° oven acts equally well)until most of the water has evaporated.

From this point the evaporation iseffected in the oven. Satisfactoryresults are obtained in an oven[20]

measuring 12 ins. cube, having an ironplate 0.75 in. thick lying on the bottomto distribute the heat. Strips of asbestosmillboard are placed on a shelf halfway up the oven. On these strips thedish containing the glycerine is placed.

If the temperature of the oven has beenadjusted to 160° C. with the doorclosed, a temperature of 130° to 140°can be readily maintained with the doorpartially open, and the glycerine, ormost of it, should be evaporated off atthis temperature. When only a slightvapor is seen to come off, the dish is

removed and allowed to cool.

An addition of 0.5 to 1.0 cc. of water ismade, and by a rotary motion theresidue brought wholly or nearly intosolution. The dish is then allowed toremain on a water bath or top of theoven until the excess water hasevaporated and the residue is in such acondition that on returning to the ovenat 160° C. it will not spurt. The timetaken up to this point cannot be givendefinitely, nor is it important. Usuallytwo or three hours are required. Fromthis point, however, the schedule oftime must be strictly adhered to. Thedish is allowed to remain in the oven,the temperature of which is carefullymaintained at 160° C. for one hour,

when it is removed, cooled, the residuetreated with water, and the waterevaporated as before. The residue isthen subjected to a second baking ofone hour, after which the dish isallowed to cool in a desiccator oversulphuric acid and weighed. Thetreatment with water, etc., is repeateduntil a constant loss of 1 to 1.5 mg. perhour is obtained.

In the case of acid glycerine acorrection must be made for the alkaliadded 1 cc. N/1 alkali represents anaddition of 0.03 gram. In the case ofalkaline crudes a correction should bemade for the acid added. Deduct theincrease in weight due to the

conversion of the NaOH and Na2CO3 toNaCl. The corrected weight multipliedby 100 gives the percentage of totalresidue at 160° C.

This residue is taken for thedetermination of the non-volatileacetylizable impurities (see acetinmethod).

7 . Organic residue.—Subtract the ashfrom the total residue at 160° C. Reportas organic residue at 160° C. (it shouldbe noted that alkaline salts of fattyacids are converted to carbonates onignition and that the CO3 thus derivedis not included in the organic residue).

ACETIN PROCESS FORTHE DETERMINATION

OF GLYCEROL.

This process is the one agreed upon at aconference of delegates from theBritish, French, German and Americancommittees, and has been confirmed byeach of the above committees as givingresults nearer to the truth than thebichromate method on crudes ingeneral. It is the process to be used (ifapplicable) whenever only one methodis employed. On pure glycerines theresults are identical with thoseobtained by the bichromate process.For the application of this method the

crude glycerine should not contain over60 per cent. water.

REAGENTS REQUIRED.

(A) Best Acetic Anhydride.—Thisshould be carefully selected. A goodsample must not require more than 0.1cc. normal NaOH for saponification ofthe impurities when a blank is run on7.5 cc. Only a slight color shoulddevelop during digestion of the blank.

The anhydride may be tested forstrength by the following method: Intoa weighed stoppered vessel, containing10 to 20 cc. of water, run about 2 cc. ofthe anhydride, replace the stopper and

weigh. Let stand with occasionalshaking, for several hours, to permitthe hydrolysis of all the anhydride;then dilute to about 200 cc., addphenolphthalein and titrate with N/1NaOH. This gives the total acidity dueto free acetic acid and acid formedfrom the anhydride. It is worthy of notethat in the presence of much freeanhydride a compound is formed withphenolphthalein, soluble in alkali andacetic acid, but insoluble in neutralsolutions. If a turbidity is noticedtoward the end of the neutralization itis an indication that the anhydride isincompletely hydrolyzed and inasmuchas the indicator is withdrawn from thesolution, results may be incorrect.

Into a stoppered weighing bottlecontaining a known weight of recentlydistilled aniline (from 10 to 20 cc.)measure about 2 cc. of the sample,stopper, mix, cool and weigh. Wash thecontents into about 200 cc. of coldwater, and titrate the acidity as before.This yields the acidity due to theoriginal, preformed, acetic acid plusone-half the acid due to anhydride (theother half having formed acetanilide);subtract the second result from the first(both calculated to 100 grams) anddouble the result, obtaining the cc. N/1NaOH per 100 grams of the sample. 1cc. N/NaOH equals 0.0510 anhydride.

(B) Pure Fused Sodium Acetate.—Thepurchased salt is again completely

fused in a platinum, silica or nickeldish, avoiding charring, powderedquickly and kept in a stoppered bottleor desiccator. It is most important thatthe sodium acetate be anhydrous.

(C) A Solution of Caustic Soda forNeutralizing, of about N/ 1 Strength,Free from Carbonate.—This can bereadily made by dissolving puresodium hydroxide in its own weight ofwater (preferably water free fromcarbon dioxide) and allowing to settleuntil clear, or filtering through anasbestos or paper filter. The clearsolution is diluted with water free fromcarbon dioxide to the strength required.

(D) N/ 1 Caustic Soda Free from

Carbonate.—Prepared as above andcarefully standardized. Some causticsoda solutions show a markeddiminution in strength after beingboiled; such solutions should berejected.

(E) N/1 Acid.—Carefully standardized.

(F) Phenolphthalein Solution.—0.5 percent. phenolphthalein in alcohol andneutralized.

THE METHOD.

In a narrow-mouthed flask (preferablyround-bottomed), capacity about 120cc., which has been thoroughly cleaned

and dried, weigh accurately and asrapidly as possible 1.25 to 1.5 grams ofthe glycerine. A Grethan or Lungepipette will be found convenient. Addabout 3 grams of the anhydrous sodiumacetate, then 7.5 cc. of the aceticanhydride, and connect the flask withan upright Liebig condenser. Forconvenience the inner tube of thiscondenser should not be over 50 cm.long and 9 to 10 mm. inside diameter.The flask is connected to the condenserby either a ground glass joint(preferably) or a rubber stopper. If arubber stopper is used it should havehad a preliminary treatment with hotacetic anhydride vapor.

Heat the contents and keep just boiling

for one hour, taking precautions toprevent the salts drying on the sides ofthe flask.

Allow the flask to cool somewhat, andthrough the condenser tube add 50 cc.of distilled water free from carbondioxide at a temperature of about 80°C., taking care that the flask is notloosened from the condenser. Theobject of cooling is to avoid anysudden rush of vapors from the flask onadding water, and to avoid breaking theflask. Time is saved by adding thewater before the contents of the flasksolidify, but the contents may beallowed to solidify and the testproceeded with the next day withoutdetriment, bearing in mind that the

anhydride in excess is much moreeffectively hydrolyzed in hot than incold water. The contents of the flaskmay be warmed to, but must notexceed, 80° C., until the solution iscomplete, except a few dark flocksrepresenting organic impurities in thecrude. By giving the flask a rotarymotion, solution is more quicklyeffected.

Cool the flask and contents withoutloosening from the condenser. Whenquite cold wash down the inside of thecondenser tube, detach the flask, washoff the stopper or ground glassconnection into the flask, and filter thecontents through an acid-washed filterinto a Jena glass flask of about 1 litre

capacity. Wash thoroughly with colddistilled water free from carbondioxide. Add 2 cc. of phenolphthaleinsolution (F), then run in caustic sodasolution (C) or (D) until a faint pinkishyellow color appears throughout thesolution. This neutralization must bedone most carefully; the alkali shouldbe run down the sides of the flask, thecontents of which are kept rapidlyswirling with occasional agitation orchange of motion until the solution isnearly neutralized, as indicated by theslower disappearance of the colordeveloped locally by the alkali runninginto the mixture. When this point isreached the sides of the flask arewashed down with carbon dioxide-free

water and the alkali subsequentlyadded drop by drop, mixing after eachdrop until the desired tint is obtained.

Now run in from a burette 50 cc. or acalculated excess of N/1 NaOH (D) andnote carefully the exact amount. Boilgently for 15 minutes, the flask beingfitted with a glass tube acting as apartial condenser. Cool as quickly aspossible and titrate the excess of NaOHwi t h N/1 acid (E) until the pinkishyellow or chosen end-point color justremains.[21] A further addition of theindicator at this point will cause anincrease of the pink color; this must beneglected, and the first end-point taken.

From the N/1 NaOH consumed

calculate the percentage of glycerol(including acetylizable impurities)after making the correction for theblank test described below.

1 cc. N/1 NaOH = 0.03069 gramglycerol.

The coefficient of expansion fornormal solutions is 0.00033 per cc. foreach degree centigrade. A correctionshould be made on this account ifnecessary.

Blank Test.—As the acetic anhydrideand sodium acetate may containimpurities which affect the result, it isnecessary to make a blank test, usingthe same quantities of acetic anhydride,

sodium acetate and water as in theanalysis. It is not necessary to filter thesolution of the melt in this case, butsufficient time must be allowed for thehydrolysis of the anhydride beforeproceeding with the neutralization.After neutralization it is not necessaryto add more than 10 cc. of the N/1alkali (D), as this represents the excessusually present after the saponificationof the average soap lye crude. Indetermining the acid equivalent of theN/1 NaOH, however, the entire amounttaken in the analysis, 50 cc., should betitrated after dilution with 300 cc.water free from carbon dioxide andwithout boiling.

Determination of the Glycerol Value of

the Acetylizable Impurities.—The totalresidue at 160° C. is dissolved in 1 or 2cc. of water, washed into theacetylizing flask and evaporated todryness. Then add anhydrous sodiumacetate and acetic anhydride in theusual amounts and proceed asdescribed in the regular analysis. Aftercorrecting for the blank, calculate theresult to glycerol.

WAYS OF CALCULATINGACTUAL GLYCEROL

CONTENT.

(1) Determine the apparent percentageof glycerol in the sample by the acetinprocess as described. The result willinclude acetylizable impurities if anyare present.

(2) Determine the total residue at 160°C.

(3) Determine the acetin value of theresidue at (2) in terms of glycerol.

(4) Deduct the result found at (3) fromthe percentage obtained at (1) and

report this corrected figure as glycerol.If volatile acetylizable impurities arepresent these are included in thisfigure.

Trimethyleneglycol is more volatilethan glycerine and can therefore beconcentrated by fractional distillation.An approximation to the quantity canbe obtained from the spread betweenthe acetin and bichromate results onsuch distillates. The spread multipliedby 1.736 will give the glycol.

BICHROMATE PROCESSFOR GLYCEROL

DETERMINATION.

REAGENTS REQUIRED.

(A) Pure potassium bichromatepowdered and dried in air free fromdust or organic vapors, at 110° to 120°C. This is taken as the standard.

(B) Dilute Bichromate Solution.—7.4564 grams of the above bichromateare dissolved in distilled water and thesolution made up to one liter at 15.5°C.

(C) Ferrous Ammonium Sulphate.—Itis never safe to assume this salt to beconstant in composition and it must bestandardized against the bichromate asfollows: dissolve 3.7282 grams of

bichromate (A) in 50 cc. of water. Add50 cc. of 50 per cent. sulphuric acid (byvolume), and to the cold undilutedsolution add from a weighing bottle amoderate excess of the ferrousammonium sulphate, and titrate backwith the dilute bichromate (B).Calculate the value of the ferrous saltin terms of bichromate.

(D) Silver Carbonate.—This isprepared as required for each test from140 cc. of 0.5 per cent. silver sulphatesolution by precipitation, with about4.9 cc. N/1 sodium carbonate solution(a little less than the calculatedquantity of N/1 sodium carbonateshould be used as an excess to preventrapid settling). Settle, decant and wash

one by decantation.

(E) Subacetate of Lead.—Boil a 10 percent. solution of pure lead acetate withan excess of litharge for one hour,keeping the volume constant, and filterwhile hot. Disregard any precipitatewhich subsequently forms. Preserveout of contact with carbon dioxide.

(F) Potassium Ferricyanide.—A verydilute, freshly prepared solutioncontaining about 0.1 per cent.

THE METHOD.

Weigh 20 grams of the glycerine,dilute to 250 cc. and take 25 cc. Add

the silver carbonate, allow to stand,with occasional agitation, for about 10minutes, and add a slight excess (about5 cc. in most cases) of the basic leadacetate (E), allow to stand a fewminutes, dilute with distilled water to100 cc., and then add 0.15 cc. tocompensate for the volume of theprecipitate, mix thoroughly, filterthrough an air-dry filter into a suitablenarrow-mouthed vessel, rejecting thefirst 10 cc., and return the filtrate if notclear and bright. Test a portion of thefiltrate with a little basic lead acetate,which should produce no furtherprecipitate (in the great majority ofcases 5 cc. are ample, but occasionallya crude will be found requiring more,

and in this case another aliquot of 25cc. of the dilute glycerine should betaken and purified with 6 cc. of thebasic acetate). Care must be taken toavoid a marked excess of basic acetate.

Measure off 25 cc. of the clear filtrateinto a flask or beaker (previouslycleaned with potassium bichromate andsulphuric acid). Add 12 drops ofsulphuric acid (1: 4) to precipitate thesmall excess of lead as sulphate. Add3.7282 grams of the powderedpotassium bichromate (A). Rinse downthe bichromate with 25 cc. of water andlet stand with occasional shaking untilall the bichromate is dissolved (noreduction will take place in the cold).

Now add 50 cc. of 50 per cent.sulphuric acid (by volume) andimmerse the vessel in boiling water fortwo hours and keep protected from dustand organic vapors, such as alcohol, tillthe titration is completed. Add from aweighing bottle a slight excess of theferrous ammonium sulphate (C),making spot tests on a porcelain platewith the potassium ferricyanide (F).Titrate back with the dilute bichromate.From the amount of bichromatereduced calculate the percentage ofglycerol.

1 gram glycerol = 7.4564 gramsbichromate.

1 gram bichromate = 0.13411 gram

glycerol.

The percentage of glycerol obtainedabove includes any oxidizableimpurities present after thepurification. A correction for the non-volatile impurities may be made byrunning a bichromate test on theresidue at 160° C.

NOTES.

(1) It is important that theconcentration of acid in the oxidationmixture and the time of oxidationshould be strictly adhered to.

(2) Before the bichromate is added to

the glycerine solution it is essentialthat the slight excess of lead beprecipitated with sulphuric acid, asstipulated.

(3) For crudes practically free fromchlorides the quantity of silvercarbonate may be reduced to one-fifthand the basic lead acetate to 0.5 cc.

(4) It is sometimes advisable to add alittle potassium sulphate to insure aclear filtrate.

SAMPLING CRUDEGLYCERINE.

The usual method of sampling crude

glycerine hitherto has been by meansof a glass tube, which is slowlylowered into the drum with the objectof taking as nearly as possible avertical section of the glycerinecontained in the drum. This method hasbeen found unsatisfactory, owing to thefact that in cold climates glycerine runsinto the tube very slowly, so that,owing to the time occupied, it isimpossible to take a complete sectionof the crude. Another objection to theglass tube is that it fails to takeanything approaching a correctproportion of any settled salt containedin the drum.

The sampler which is illustratedherewith has been devised with the

object of overcoming the objections tothe glass tube as far as possible. Itconsists of two brass tubes, one fittingclosely inside the other. A number ofports are cut out in each tube in such away that when the ports are opened acontinuous slot is formed whichenables a complete section to be takenthroughout the entire length of thedrum. By this arrangement theglycerine fills into the sampler almostinstantaneously. There are a number ofports cut at the bottom of the samplerwhich render it possible to take aproportion of the salt at the bottom ofthe drum. The instrument is soconstructed that all the ports, includingthe bottom ones, can be closed

simultaneously by the simple action ofturning the handle at the top; a pointeris arranged which indicates on a dialwhen the sampler is open or closed. Insamplers of larger section (1 in.) it ispossible to arrange a third motionwhereby the bottom ports only are openfor emptying, but in samplers ofsmaller dimensions (5/8 in.) this thirdmotion must be dispensed with,otherwise the dimensions of the portshave to be so small that the samplerwould not be efficient.

In using the sampler it is introducedinto the drum with the ports closed, andwhen it has touched the bottom, theports are opened for a second or two,then closed and withdrawn, and the

sample discharged into the receivingvessel by opening the ports. When thedrum contains salt which hasdeposited, the ports must be openedbefore the sampler is pushed throughthe salt, thus enabling a portion to beincluded in the sample. It is, however,almost impossible to obtain a correctproportion of salt after it has settled inthe drum and it is thereforerecommended that the drum besampled before any salt has deposited.A sampler 1 in. in diameter withdrawsapproximately 10 oz. from a 110-gal.drum. A sampler 5/8 in. in diameterwill withdraw about 5 oz.

FOOTNOTES:

[13] Zeit. Angew. Chem. 19, 385(1906).

[14] Zeit. Angew. Chem. 27, 11-20(1914).

[15] Bull. 107, Bur. Chem. U. S.Dept. Agriculture.

[16] Richards and Gies, Am. J.Physiol. (1902) 7, 129.

[17] Seifensieder Ztg. (1913) No.46.

[18] Bull 107, Bur. Chem. U. S.Dept. Agriculture.

[19] Carbon is readily burned offcompletely, without loss ofchlorides, in a gas-heated mufflefurnace adjusted to a dull red heat.

[20] An electric oven suitable for

this work, which is readily adjustedto 160 degs. C., has been made forMr. Low and the chairman, by theApparatus and Specialty Company,Lansing, Mich. Its size is 9-1/2 × 10× 16 inches, and capacity 8 Petriedishes. It gives a strong draft atconstant temperature.

[21] A precipitate at this point is anindication of the presence of iron oralumina, and high results will beobtained unless a correction is madeas described below.

CHAPTER VII

Standard Methods for theSampling and Analysis of

Commercial Fats and Oils[22]

The following report of the Committeeon Analysis of Commercial Fats andOils of the Division of IndustrialChemists and Chemical Engineers ofthe American Chemical Society wasadopted April 14, 1919, by unanimousvote:

W. D. RICHARDSON, Chairman, Swift and

Co., Chicago, Ill.

R. W. BAILEY, Stillwell and Gladding,New York City.

W. J. GASCOYNE, W. J. Gascoyne andCo., Baltimore, Md.

I. KATZ,[A] Wilson and Co., Chicago,Ill.

A. LOWENSTEIN,[A] Morris and Co.,Chicago, Ill.

H. J. MORRISON, Proctor and Gamble Co.,Ivorydale, Ohio.

J. R. POWELL, Armour Soap Works,Chicago, Ill.

R. J. QUINN,[A] Midland Chemical Co.,

Argo, Ill.

PAUL RUDNICK, Armour and Co.,Chicago, Ill.

L. M. TOLMAN, Wilson and Co., Chicago,Ill.

E. TWITCHELL,[A] Emery Candle Co.,Cincinnati, Ohio.

J. J. VOLLERTSEN, Morris and Co.,Chicago, Ill.

[Note A: Resigned.]

Scope, Applicability andLimitations of the Methods.

SCOPE.

These methods are intended to aid indetermining the commercial valuationof fats and fatty oils in their purchaseand sale, based on the fundamentalassumption commonly recognized inthe trade, namely, that the product istrue to name and is not adulterated. Formethods for determining the identity ofoils and fats, the absence of adulterantstherein and for specific tests used inparticular industries, the chemist isreferred to standard works on theanalysis of fats and oils.

APPLICABILITY.

The methods are applicable incommercial transactions involving fatsand fatty oils used in the soap, candleand tanning industries, to edible fatsand oils and to fats and fatty oilsintended for lubricating and burningpurposes. The methods are applicableto the raw oils used in the varnish andpaint industry with the exceptionsnoted under limitations, but specialmethods have not been included.

LIMITATIONS.

The methods have not been developedwith special reference to waxes(beeswax, carnauba wax, wool wax,etc.) although some of them may be

found applicable to these substances.The Committee considers the Wijsmethod superior to the Hanus methodfor the determination of iodine numberof linseed oil as well as other oils,although the Hanus method has beenconsidered standard for this work forsome time and has been adopted by theAmerican Society for TestingMaterials and in various specifications.It has been customary to use the Hüblmethod for the determination of iodinevalue of tung oil (China wood oil) butthe Committee's work indicates that theWijs method is satisfactory for thisdetermination.

Sampling.

TANK CARS.

1 . SAMPLING WHILE LOADING—Sampleshall be taken at discharge of pipewhere it enters tank car dome. The totalsample taken shall be not less than 50lbs. and shall be a composite of smallsamples of about 1 pound each, takenat regular intervals during the entireperiod of loading.

The sample thus obtained is thoroughlymixed and uniform 3-lb. portionsplaced in air-tight 3-lb. metalcontainers. At least three such samplesshall be put up, one for the buyer, onefor the seller, and the third to be sent toa referee chemist in case of dispute. All

samples are to be promptly andcorrectly labeled and sealed.

2. SAMPLING FROM CAR ON TRACK[23]—(a)When contents are solid.[24] In thiscase the sample is taken by means of alarge tryer measuring about 2 in. acrossand about 1-1/2 times the depth of thecar in length. Several tryerfuls aretaken vertically and obliquely towardthe ends of the car until 50 lbs. areaccumulated, when the sample issoftened, mixed and handled as under(1). In case the contents of the tank carhave assumed a very hard condition, asin Winter weather, so that it isimpossible to insert the tryer, and itbecomes necessary to soften the

contents of the car by means of theclosed steam coil (in nearly all tankcars the closed steam coil leaks) or bymeans of open steam in order to draw aproper sample, suitable arrangementsmust be made between buyer and sellerfor the sampling of the car after it issufficiently softened, due considerationbeing given to the possible presence ofwater in the material in the car asreceived and also to the possibleaddition of water during the steaming.The Committee knows of no directmethod for sampling a hard-frozentank car of tallow in a satisfactorymanner.

(b) When contents are liquid. Thesample taken is to be a 50-lb.

composite made up of numerous smallsamples taken from the top, bottom andintermediate points by means of abottle or metal container withremovable stopper or top. This deviceattached to a suitable pole is lowered tothe various desired depths, when thestopper or top is removed and thecontainer allowed to fill. The 50-lb.sample thus obtained is handled asunder (1).

In place of the device described above,any sampler capable of taking a samplefrom the top, bottom, and center, orfrom a section through car, may beused.

(c) When contents are in semi-solid

condition, or when stearine hasseparated from liquid portions. In thiscase, a combination of (a) and (b) maybe used or by agreement of the partiesthe whole may be melted andprocedure (b) followed.

BARRELS, TIERCES, CASKS,DRUMS, AND OTHER PACKAGES.

All packages shall be sampled, unlessby special agreement the partiesarrange to sample a lesser number; butin any case not less than 10 per cent ofthe total number shall be sampled. Thetotal sample taken shall be at least 20lbs. in weight for each 100 barrels, orequivalent.

1 . BARRELS, TIERCES AND CASKS—(a)When contents are solid. The smallsamples shall be taken by a tryerthrough the bunghole or through aspecial hole bored in the head or sidefor the purpose, with a 1-in. or largerauger. Care should be taken to avoidand eliminate all borings and chipsfrom the sample. The tryer is insertedin such a way as to reach the head ofthe barrel, tierce, or cask. The largesample is softened, mixed and handledaccording to TANK CARS (1).

(b) When contents are liquid. In thiscase use is made of a glass tube withconstricted lower end. This is insertedslowly and allowed to fill with theliquid, when the upper end is closed

and the tube withdrawn, the contentsbeing allowed to drain into the samplecontainer. After the entire sample istaken it is thoroughly mixed andhandled according to TANK CARS (1).

(c) When contents are semi-solid. Inthis case the tryer or a glass tube withlarger outlet is used, depending on thedegree of fluidity.

(d) Very hard materials, such asnatural and artificial stearines. Bypreference the barrels are stripped andsamples obtained by breaking upcontents of at least 10 per cent of thepackages. This procedure is to befollowed also in the case of cakesshipped in sacks. When shipped in the

form of small pieces in sacks they canbe sampled by grab sampling andquartering. In all cases the finalprocedure is as outlined under TANK

CARS (1).

2 . DRUMS—Samples are to be taken asunder (1), use being made of thebunghole. The tryer or tube should besufficiently long to reach to the ends ofthe drum.

3 . OTHER PACKAGES—Tubs, pails andother small packages not mentionedabove are to be sampled by tryer ortube (depending on fluidity) as outlinedabove, the tryer or tube being inserteddiagonally whenever possible.

4. MIXED LOTS AND PACKAGES—When lotsof tallow or other fats are received inpackages of various shapes and sizes,and especially wherein the fat itself isof variable composition, such must beleft to the judgment of the sampler. Ifvariable, the contents of each packageshould be mixed as thoroughly aspossible and the amount of theindividual samples taken madeproportional to the sizes of thepackages.

Analysis.

SAMPLE.

The sample must be representative and

at least three pounds in weight andtaken in accordance with the STANDARD

METHODS FOR THE SAMPLING OF COMMERCIAL

FATS AND OILS. It must be kept in an air-tight container, in a dark, cool place.

Soften the sample if necessary bymeans of a gentle heat, taking care notto melt it. When sufficiently softened,mix the sample thoroughly by means ofa mechanical egg beater or otherequally effective mechanical mixer.

MOISTURE AND VOLATILEMATTER.

APPARATUS: Vacuum Oven—TheCommittee Standard Oven.

DESCRIPTION—The Standard F. A. C.Vacuum Oven has been designed withthe idea of affording a simple andcompact vacuum oven which will giveas uniform temperatures as possible onthe shelf. As the figure shows, itconsists of an iron casting ofrectangular sections with hinged frontdoor made tight by means of a gasketand which can be lowered on openingthe oven so as to form a shelf on whichsamples may be rested. The ovencontains but one shelf which is heatedfrom above as well as below by meansof resistance coils. Severalthermometer holes are provided inorder to ascertain definitely thetemperature at different points on the

shelf. In a vacuum oven where theheating is done almost entirely byradiation it is difficult to maintainuniform temperatures at all points, butthe F. A. C. oven accomplishes thisrather better than most vacuum ovens.Larger ovens containing more than oneshelf have been tried by theCommittee, but have been found to belacking in temperature uniformity andmeans of control. The entire oven issupported by means of a 4-in. standardpipe which screws into the base of theoven and which in turn is supported bybeing screwed into a blind flange ofsuitable diameter which rests on thefloor or work table.

Moisture Dish—A shallow, glass dish,

lipped, beaker form, approximately 6to 7 cm. diameter and 4 cm. deep, shallbe standard.

DETERMINATION—Weigh out 5 grams (=0.2 g. of the prepared sample) into amoisture dish. Dry to constant weightin vacuo at a uniform temperature, notless than 15° C. nor more than 20° C.above the boiling point of water at theworking pressure, which must notexceed 100 mm. of mercury.[25]

Constant weight is attained whensuccessive dryings for 1-hr. periodsshow an additional loss of not morethat 0.05 per cent. Report loss inweight as MOISTURE AND VOLATILE

MATTER.[26]

Standard Vacuum Oven

The vacuum-oven method cannot beconsidered accurate in the case of fatsof the coconut oil group containing free

acid and the Committee recommendsthat it be used only for oils of thisgroup when they contain less than 1 percent free acid. In the case of oils of thisgroup containing more than 1 per centfree acid, recourse should be hadtemporarily to the routine controlmethod for moisture and volatilematter[27] until the Committeedevelops a more satisfactory method.

The air-oven method cannot beconsidered even approximatelyaccurate in the case of the drying andsemi-drying oils and those of thecoconut oil group. Therefore, in thecase of such oils as cottonseed oil,maize oil (corn oil), soy bean oil,

linseed oil, coconut oil, palm kerneloil, etc., the vacuum-oven methodshould always be used, except in thecase of fats of the coconut groupcontaining more than 1 per cent freeacid, as noted above.

INSOLUBLE IMPURITIES.

Dissolve the residue from the moistureand volatile matter determination byheating it on a steam bath with 50 cc.of kerosene. Filter the solution througha Gooch crucible properly preparedwith asbestos,[28] wash the insolublematter five times with 10-cc. portionsof hot kerosene, and finally wash theresidual kerosene out thoroughly with

petroleum ether. Dry the crucible andcontents to constant weight, as in thedetermination of moisture and volatilematter and report results as INSOLUBLE

IMPURITIES.

SOLUBLE MINERAL MATTER.

Place the combined kerosene filtrateand kerosene washings from theinsoluble impurities determination in aplatinum dish. Place in this an ashlessfilter paper folded in the form of acone, apex up. Light the apex of thecone, whereupon the bulk of thekerosene burns quietly. Ash the residuein a muffle, to constant weight, takingcare that the decomposition of alkaline

earth carbonates is complete, andreport the result as SOLUBLE MINERAL

MATTER.[29] When the percentage ofsoluble mineral matter amounts tomore than 0.1 per cent, multiply thepercentage by 10 and add this amountto the percentage of free fatty acids asdetermined.[30]

FREE FATTY ACIDS.

T h e ALCOHOL[31] used shall beapproximately 95 per cent ethylalcohol, freshly distilled from sodiumhydroxide, which with phenolphthaleingives a definite and distinct end-point.

DETERMINATION—Weigh 1 to 15 g. of the

prepared sample into an Erlenmeyerflask, using the smaller quantity in thecase of dark-colored, high acid fats.Add 50 to 100 cc. hot, neutral alcohol,and titrate with N/ 2 , N/4 or N/10sodium hydroxide depending on thefatty acid content, usingphenolphthalein as indicator. Calculateto oleic acid, except that in the case ofpalm oil the results may also beexpressed in terms of palmitic acid,clearly indicating the two methods ofcalculation in the report. In the case ofcoconut and palm kernel oils, calculateto and report in terms of lauric acid inaddition to oleic acid, clearlyindicating the two methods ofcalculation in the report. In the case of

fats or greases containing more than0.1 per cent of soluble mineral matter,add to the percentages of free fattyacids as determined 10 times thepercentage of bases in the solublemineral matter as determined.[30] Thisaddition gives the equivalent of fattyacids combined with the solublemineral matter.

TITER.

STANDARD THERMOMETER—Thethermometer is graduated at zero andin tenth degrees from 10° C. to 65° C.,with one auxiliary reservoir at theupper end and another between the zeromark and the 10° mark. The cavity in

the capillary tube between the zeromark and the 10° mark is at least 1 cm.below the 10° mark, the 10° mark isabout 3 or 4 cm. above the bulb, thelength of the thermometer being about37 cm. over all. The thermometer hasbeen annealed for 75 hrs. at 450° C.and the bulb is of Jena normal 16'''glass, or its equivalent, moderatelythin, so that the thermometer will bequick-acting. The bulb is about 3 cm.long and 6 mm. in diameter. The stemof the thermometer is 6 mm. indiameter and made of the bestthermometer tubing, with scale etchedon the stem, the graduation is clear-cutand distinct, but quite fine. Thethermometer must be certified by the

U. S. Bureau of Standards.

GLYCEROL CAUSTIC SOLUTION—Dissolve250 g. potassium hydroxide in 1900 cc.dynamite glycerin with the aid of heat.

DETERMINATION—Heat 75 cc. of theglycerol-caustic solution to 150° C. andadd 50 g. of the melted fat. Stir themixture well and continue heating untilthe melt is homogeneous, at no timeallowing the temperature to exceed150° C. Allow to cool somewhat andcarefully add 50 cc. 30 per cent sulfuricacid. Now add hot water and heat untilthe fatty acids separate out perfectlyclear. Draw off the acid water and washthe fatty acids with hot water until freefrom mineral acid, then filter and heat

to 130° C. as rapidly as possible whilestirring. Transfer the fatty acids, whencooled somewhat, to a 1-in. by 4-in.titer tube, placed in a 16-oz. salt-mouthbottle of clear glass, fitted with a corkthat is perforated so as to hold the tuberigidly when in position. Suspend thetiter thermometer so that it can be usedas a stirrer and stir the fatty acidsslowly (about 100 revolutions perminute) until the mercury remainsstationary for 30 seconds. Allow thethermometer to hang quietly with thebulb in the center of the tube and reportthe highest point to which the mercuryrises as the titer of the fatty acids. Thetiter should be made at about 20° C. forall fats having a titer above 30° C. and

at 10° C. below the titer for all otherfats. Any convenient means may beused for obtaining a temperature of 10°below the titer of the various fats. Thecommittee recommends first of all achill room for this purpose; second, anartificially chilled small chamber withglass window; third, immersion of thesalt-mouth bottle in water or otherliquid of the desired temperature.

UNSAPONIFIABLE MATTER.

EXTRACTION CYLINDER—The cylindershall be glass-stoppered, graduated at40 cc., 80 cc. and 130 cc., and of thefollowing dimensions: diameter about1-3/8 in., height about 12 in.

PETROLEUM ETHER—Redistilledpetroleum ether, boiling under 75° C.,shall be used. A blank must be made byevaporating 250 cc. with about 0.25 g.of stearine or other hard fat (previouslybrought to constant weight by heating)and drying as in the actualdetermination. The blank must notexceed a few milligrams.

DETERMINATION—Weigh 5 g. (±0.20 g.)of the prepared sample into a 200-cc.Erlenmeyer flask, add 30 cc. ofredistilled 95 per cent (approximately)ethyl alcohol and 5 cc. of 50 per centaqueous potassium hydroxide, and boilthe mixture for one hour under a refluxcondenser. Transfer to the extractioncylinder and wash to the 40-cc. mark

with redistilled 95 per cent ethylalcohol. Complete the transfer, firstwith warm, then with cold water, tillthe total volume amounts to 80 cc.Cool the cylinder and contents to roomtemperature and add 50 cc. ofpetroleum ether. Shake vigorously forone minute and allow to settle untilboth layers are clear, when the volumeof the upper layer should be about 40cc. Draw off the petroleum ether layeras closely as possible by means of aslender glass siphon into a separatoryfunnel of 500 cc. capacity. Repeatextraction at least four more times,using 50 cc. of petroleum ether eachtime. More extractions than five arenecessary where the unsaponifiable

matter runs high, say over 5 per cent,and also in some cases where it islower than 5 per cent, but is extractedwith difficulty. Wash the combinedextracts in a separatory funnel threetimes with 25-cc. portions of 10 percent alcohol, shaking vigorously eachtime. Transfer the petroleum etherextract to a wide-mouth tared flask orbeaker, and evaporate the petroleumether on a steam bath in an air current.Dry as in the method for MOISTURE AND

VOLATILE MATTER. Any blank must bededucted from the weight beforecalculating unsaponifiable matter. Testthe final residue for solubility in 50 cc.petroleum ether at room temperature.Filter and wash free from the insoluble

residue, if any, evaporate and dry in thesame manner as before. TheCommittee wishes to emphasize thenecessity of thorough and vigorousshaking in order to secure accurateresults. The two phases must bebrought into the most intimate contactpossible, otherwise low anddisagreeing results may be obtained.

IODINE NUMBER—WIJSMETHOD.

PREPARATION OF REAGENTS—Wijs IodineSolution—Dissolve 13.0 g. ofresublimed iodine in one liter of C. P.glacial acetic acid and pass in washedand dried chlorine gas until the original

thiosulfate titration of the solution isnot quite doubled. The solution is thenpreserved in amber glass-stopperedbottles, sealed with paraffin until readyfor use.

Mark the date on which the solution isprepared on the bottle or bottles and donot use Wijs solution which is morethan 30 days old.

There should be no more than a slightexcess of iodine, and no excess ofchlorine. When the solution is madefrom iodine and chlorine, this point canbe ascertained by not quite doublingthe titration.[32]

The glacial acetic acid used for

preparation of the Wijs solution shouldbe of 99.0 to 99.5 per cent strength. Incase of glacial acetic acids ofsomewhat lower strength, theCommittee recommends freezing andcentrifuging or draining as a means ofpurification.

N/ 1 0 Sodium Thiosulfate Solution—Dissolve 24.8 g. of C. P. sodiumthiosulfate in recently boiled distilledwater and dilute with the same to oneliter at the temperature at which thetitrations are to be made.

Starch Paste—Boil 1 g. of starch in200 cc. of distilled water for 10 min.and cool to room temperature.

An improved starch solution may beprepared by autoclaving 2 g. of starchand 6 g. of boric acid dissolved in 200cc. water at 15 lbs. pressure for 15 min.This solution has good keepingqualities.

Potassium Iodide Solution—Dissolve150 g. of potassium iodide in water andmake up to one liter.

N/10 Potassium Bichromate—Dissolve4.903 g. of C. P. potassium bichromatein water and make the volume up toone liter at the temperature at whichtitrations are to be made.

The Committee calls attention to thefact that occasionally potassium

bichromate is found containing sodiumbichromate, although this is of rareoccurrence. If the analyst suspects thathe is dealing with an impure potassiumbichromate, the purity can beascertained by titration against re-sublimed iodine. However, this isunnecessary in the great majority ofcases.

Standardization of the SodiumThiosulfate Solution—Place 40 cc. ofthe potassium bichromate solution, towhich has been added 10 cc. of thesolution of potassium iodide, in aglass-stoppered flask. Add to this 5 cc.of strong hydro-chloric acid. Dilutewith 100 cc. of water, and allow theN/10 sodium thiosulfate to flow slowly

into the flask until the yellow color ofthe liquid has almost disappeared. Adda few drops of the starch paste, andwith constant shaking continue to addt h e N/10 sodium thiosulfate solutionuntil the blue color just disappears.

DETERMINATION—Weigh accurately from0.10 to 0.50 g. (depending on the iodinenumber) of the melted and filteredsample into a clean, dry, 16-oz. glass-stoppered bottle containing 15-20 cc.of carbon tetrachloride or chloroform.Add 25 cc. of iodine solution from apipette, allowing to drain for a definitetime. The excess of iodine should befrom 50 per cent to 60 per cent of theamount added, that is, from 100 percent to 150 per cent of the amount

absorbed. Moisten the stopper with a15 per cent potassium iodide solutionto prevent loss of iodine or chlorine butguard against an amount sufficient torun down inside the bottle. Let thebottle stand in a dark place for 1/2 hr.at a uniform temperature. At the end ofthat time add 20 cc. of 15 per centpotassium iodide solution and 100 cc.of distilled water. Titrate the iodinewith N/10 sodium thiosulfate solutionwhich is added gradually, with constantshaking, until the yellow color of thesolution has almost disappeared. Add afew drops of starch paste and continuetitration until the blue color hasentirely disappeared. Toward the end ofthe reaction stopper the bottle and

shake violently so that any iodineremaining in solution in thetetrachloride or chloroform may betaken up by the potassium iodidesolution. Conduct two determinationson blanks which must be run in thesame manner as the sample except thatno fat is used in the blanks. Slightvariations in temperature quiteappreciably affect the titer of theiodine solution, as acetic acid has ahigh coefficient of expansion. It is,therefore, essential that the blanks anddeterminations on the sample be madeat the same time. The number of cc. ofstandard thiosulfate solution requiredby the blank, less the amount used inthe determination, gives the thiosulfate

equivalent of the iodine absorbed bythe amount of sample used in thedetermination. Calculate to centigramsof iodine absorbed by 1 g. of sample (=per cent iodine absorbed).

DETERMINATION, TUNG OIL—Tung oilshows an erratic behavior with mostiodine reagents and this is particularlynoticeable in the case of the Hanusreagent which is entirely unsuitable fordetermining the iodine number of thisoil since extremely high and irregularresults are obtained. The Hübl solutionshows a progressive absorption up to24 hrs. and probably for a longer timebut the period required is entirely toolong for a chemical determination. TheWijs solution gives good results if the

following precautions are observed:

Weigh out 0.15 ± 0.05 g., use an excessof 55 ± 3 per cent Wijs solution.Conduct the absorption at atemperature of 20-25° C. for 1 hr. Inother respects follow the instructionsdetailed above.

SAPONIFICATION NUMBER(KOETTSTORFER NUMBER).

PREPARATION OF REAGENTS. N/2Hydrochloric Acid—Carefullystandardized.

Alcoholic Potassium HydroxideSolution—Dissolve 40 g. of purepotassium hydroxide in one liter of 95

per cent redistilled alcohol (byvolume). The alcohol should beredistilled from potassium hydroxideover which it has been standing forsome time, or with which it has beenboiled for some time, using a refluxcondenser. The solution must be clearand the potassium hydroxide free fromcarbonates.

DETERMINATION—Weigh accurate about 5g. of the filtered sample into a 250 to300 cc. Erlenmeyer flask. Pipette 50 cc.of the alcoholic potassium hydroxidesolution into the flask, allowing thepipette to drain for a definite time.Connect the flask with an air condenserand boil until the fat is completelysaponified (about 30 minutes). Cool

and titrate with the N/2 hydrochloricacid, using phenolphthalein as anindicator. Calculate the Koettstorfernumber (mg. of potassium hydroxiderequired to saponify 1 g. of fat).Conduct 2 or 3 blank determinations,using the same pipette and draining forthe same length of time as above.

MELTING POINT.

APPARATUS—Capillary tubes made from5 mm. inside diameter thin-walledglass tubing drawn out to 1 mm. insidediameter. Length of capillary part oftubes to be about 5 cm. Length of tubeover all 8 cm.

Standard thermometer graduated intenths of a degree.

600 cc. beaker.

DETERMINATION—The sample should beclear when melted and entirely freefrom moisture, or incorrect results willbe obtained.

Melt and thoroughly mix the sample.Dip three of the capillary tubes abovedescribed in the oil so that the fat in thetube stands about 1 cm. in height. Nowfuse the capillary end carefully bymeans of a small blast flame and allowto cool. These tubes are placed in arefrigerator over night at a temperatureof from 40 to 50° F. They are then

fastened by means of a rubber band orother suitable means to the bulb of athermometer graduated in tenths of adegree. The thermometer is suspendedin a beaker of water (which is agitatedby air or other suitable means) so thatthe bottom of the bulb of thethermometer is immersed to a depth ofabout 3 cm. The temperature of thewater is increased gradually at the rateof about 1° per minute.

The point at which the sample becomesopalescent is first noted and the heatingcontinued until the contents of the tubebecomes uniformly transparent. Thelatter temperature is reported as themelting point.

Before finally melting to a perfectlyclear fluid, the sample becomesopalescent and usually appears clear atthe top, bottom, and sides beforebecoming clear at the center. Theheating is continued until the contentsof the tube become uniformly clear andtransparent. This temperature isreported as the melting point.[33] It isusually only a fraction of a degreeabove the opalescent point noted. Thethermometer should be read to thenearest 1/2° C., and in addition thistemperature may be reported to thenearest degree Fahrenheit if desired.

CLOUD TEST.

PRECAUTIONS—(1) The oil must beperfectly dry, because the presence ofmoisture will produce a turbiditybefore the clouding point is reached.

(2) The oil must be heated to 150° C.over a free flame, immediately beforemaking the test.

(3) There must not be too muchdiscrepancy between the temperatureof the bath and the clouding point ofthe oil. An oil that will cloud at thetemperature of hydrant water should betested in a bath of that temperature. Anoil that will cloud in a mixture of iceand water should be tested in such abath. An oil that will not cloud in abath of ice and water must be tested in

a bath of salt, ice, and water.

DETERMINATION—The oil is heated in aporcelain casserole over a free flame to150° C., stirring with the thermometer.As soon as it can be done with safety,the oil is transferred to a 4 oz. oilbottle, which must be perfectly dry.One and one-half ounces of the oil aresufficient for the test. A dry centigradethermometer is placed in the oil, andthe bottle is then cooled by immersionin a suitable bath. The oil is constantlystirred with the thermometer, takingcare not to remove the thermometerfrom the oil at any time during the test,so as to avoid stirring air bubbles intothe oil. The bottle is frequentlyremoved from the bath for a few

moments. The oil must not be allowedto chill on the sides and bottom of thebottle. This is effected by constant andvigorous stirring with the thermometer.As soon as the first permanent cloudshows in the body of the oil, thetemperature at which this cloud occursis noted.

With care, results concordant to within1/2° C. can be obtained by this method.A Fahrenheit thermometer issometimes used because it has becomecustomary to report results in degreesFahrenheit.

The oil must be tested within a shorttime after heating to 150° C. and a re-test must always be preceded by

reheating to that temperature. Thecloud point should be approached asquickly as possible, yet not so fast thatthe oil is frozen on the sides or bottomof the bottle before the cloud test isreached.

Notes on the AboveMethods.

SAMPLING.

The standard size of sample adopted bythe committee is at least 3 lbs. inweight. The committee realizes thatthis amount is larger than any samplesusually furnished even when

representing shipments of from 20,000to 60,000 lbs. but it believes that therequirement of a larger sample isdesirable and will work toward uniformand more concordant results inanalysis. It will probably continue to bethe custom of the trade to submitsmaller buyers' samples than requiredby the committee, but these are to beconsidered only as samples forinspection and not for analysis. Thestandard analytical sample mustconsist of 3 lbs. or more.

The reasons for keeping samples in adark, cool place are obvious. This is toprevent any increase in rancidity andany undue increase in free fatty acids.In the case of many fats the committee

has found in its co-operative analyticalwork that free acid tends to increasevery rapidly. This tendency isminimized by low temperatures.

MOISTURE AND VOLATILEMATTER.

After careful consideration thecommittee has decided that moisture isbest determined in a vacuum oven ofthe design which accompanies theabove report. Numerous results oncheck samples have confirmed thecommittee's conclusions. The ovenrecommended by the committee isconstructed on the basis of well-knownprinciples and it is hoped that this type

will be adopted generally by chemistswho are called upon to analyze fats andoils. The experiments of the committeeindicate that it is a most difficultmatter to design a vacuum oven whichwill produce uniform temperaturesthroughout; and one of the principalideas in the design adopted isuniformity of temperature over theentire single shelf. This idea has notquite been realized in practice but,nevertheless, the present designapproaches much closer to the idealthan other vacuum ovens commonlyused. In the drawing the essentialdimensions are those between theheating units and the shelf and thelength and breadth of the outer casting.

The standard Fat Analysis CommitteeOven (F. A. C. Oven) can be furnishedby Messrs. E. H. Sargent & Company,125 West Lake street, Chicago.

The committee realizes that for routinework a quicker method is desirable andhas added one such method and hasalso stated the conditions under whichcomparable results can be obtained bymeans of the ordinary well-ventilatedair oven held at 105 to 110° C.However, in accordance with afundamental principle adopted by thecommittee at its first meeting, only onestandard method is adopted anddeclared official for eachdetermination.

The committee realizes that in the caseof all methods for determiningmoisture by means of loss on heatingthere may be a loss due to volatilematter (especially fatty acids) otherthan water. The title of thedetermination MOISTURE AND VOLATILE

MATTER indicates this idea, but anyconsiderable error from this sourcemay occur only in the case of high acidfats and oils and particularly thosecontaining lower fatty acids such ascoconut and palm kernel oil. In thecase of extracted greases which havenot been properly purified, some of thesolvent may also be included in themoisture and volatile matterdetermination, but inasmuch as the

solvent, usually a petroleum product,can only be considered as foreignmatter, for commercial purposes, it isentirely proper to include it with themoisture.

The committee has also considered thevarious distillation methods for thedetermination of moisture in fats andoils, but since according to thefundamental principles which it wasendeavoring to follow it could onlystandardize one method, it was decidedthat the most desirable one on thewhole was the vacuum-oven method asgiven. There are cases wherein achemist may find it desirable to checka moisture determination or investigatethe moisture content of a fat or oil

further by means of one of thedistillation methods.

However, in co-operative work thedistillation method in various types ofapparatus has not yielded satisfactoryresults. The difficulties appear to beconnected with a proper choice ofsolvent and particularly with thetendency of drops of water to adhere tovarious parts of the glass apparatusinstead of passing on to the measuringdevice. When working on coconut oilcontaining a high percentage of freefatty acids, concordant results couldnot be obtained by the variousmembers of the committee whenworking with identical samples,solvents and apparatus.

On the other hand, the committeefound by individual work, co-operativework and collaborative work by severalmembers of the committee in onelaboratory, that the old, well-knowndirect heating method (which thecommittee has designated the hot platemethod) yielded very satisfactoryresults on all sorts of fats and oilsincluding emulsions such as butter andoleomargarine and even on coconut oilsamples containing 15 to 20 per centfree fatty acids and 5 to 6 per cent ofmoisture. Unfortunately, this methoddepends altogether on the operator'sskill and while the method may betaught to any person whether a chemistor not so that he can obtain excellent

results with it, it is difficult to give asufficiently, complete description of itso that any chemist anywhere afterreading the description could follow itsuccessfully. The method isundoubtedly worthy of muchconfidence in careful hands. It is quick,accurate and reliable. It is probably thebest single method for thedetermination of moisture in all sortsof samples for routine laboratory work.On account of this fact the committeedesires to announce its willingness toinstruct any person in the proper use ofthe method who desires to becomeacquainted with it and who will visitany committee member's laboratory.

INSOLUBLE IMPURITIES.

This determination, the title for whichwas adopted after carefulconsideration, determines theimpurities which have generally beenknown as dirt, suspended matter,suspended solids, foreign solids,foreign matter, etc., in the past. Thefirst solvent recommended by thecommittee is hot kerosene to befollowed by petroleum ether kept atordinary room temperature. Petroleumether, cold or only slightly warm, is nota good fat and metallic soap solvent,whereas hot kerosene dissolves thesesubstances readily, and for this reasonthe committee has recommended the

double solvent method so as to excludemetallic soaps which are determinedbelow as soluble mineral matter.


Soluble mineral matter representsmineral matter combined with fattyacids in the form of soaps in solution inthe fat or oil. Formerly, this mineralmatter was often determined incombination by weighing the separatedmetallic soap or by weighing it inconjunction with the insolubleimpurities. Since the soaps presentconsist mostly of lime soap, it has beencustomary to calculate the lime presenttherein by taking 0.1 the weight of the

total metallic soaps. The standardmethod as given above is direct andinvolves no calculation. The routinemethod given in the note has beenplaced among the methods for thereason that it is used in somelaboratories, but has not been adoptedas a standard method in view of thefact that the committee has made it arule to adopt only one standard method.It should be pointed out, however, thatthe method cannot be consideredaccurate for the reason that insolubleimpurities may vary from sample tosample to a considerable extent and theerror due to the presence of largeparticles of insoluble impurities is thustransferred to the soluble mineral

matter. The committee has found onetype of grease (naphtha bone grease)which shows most unusualcharacteristics. The type samplecontains 4.3 per cent soluble mineralmatter by the committee method whichwould be equivalent to 43.0 per centfree fatty acid. The kerosene andgasoline filtrate was particularly clear,nevertheless the ash was found tocontain 36.43 per cent P2O5 equivalentto 79.60 per cent of Ca3(PO4)2 and 9.63per cent of Fe2O3. The method,therefore, determines the solublemineral matter in this casesatisfactorily but the factor 10 is notapplicable for calculating the fattyacids combined therewith. It is

necessary, therefore, in order todetermine the fatty acids combinedwith soluble mineral matter in theoriginal sample to determine the actualbases in the soluble mineral matter asobtained by ashing the kerosene andgasoline filtrate. To the bases sodetermined the factor 10 can then beapplied.

FREE FATTY ACID.

The fatty acid method adopted issufficiently accurate for commercialpurposes. In many routine laboratoriesthe fat or oil is measured and notweighed, but the committeerecommends weighing the sample in

all cases. For scientific purposes theresult is often expressed as "acidnumber," meaning the number ofmilligrams of KOH required toneutralize the free acids in one gram offat, but the commercial practice hasbeen, and is, to express the fatty acidsas oleic acid or in the case of palm oil,as palmitic acid, in some instances.The committee sees no objection to thecontinuation of this custom so long asthe analytical report clearly indicateshow the free acid is expressed. For amore exact expression of the free acidin a given fat, the committeerecommends that the ratio of acidnumber to saponification number beused. This method of expressing results

is subject to error when unsaponifiablefatty matter is present, since the resultexpresses the ratio of free fatty acid tototal saponifiable fatty matter present.

TITER.

At the present time the prices ofglycerol and caustic potash areabnormally high, but the committeehas considered that the methodsadopted are for normal times andnormal prices. For routine work duringthe period of high prices the followingmethod may be used for preparing thefatty acids and is recommended by thecommittee:

Fifty grams of fat are saponified with60 cc. of a solution of 2 parts of methylalcohol to 1 of 50 per cent NaOH. Thesoap is dried, pulverized and dissolvedin 1000 cc. of water in a porcelain dishand then decomposed with 25 cc. of 75per cent sulphuric acid. The fatty acidsare boiled until clear oil is formed andthen collected and settled in a 150-cc.beaker and filtered into a 50-cc. beaker.They are then heated to 130° C. asrapidly as possible with stirring, andtransferred, after they have cooledsomewhat, to the usual 1-in. by 4-in.titer tube.

The method of taking the titer,including handling the thermometer, tobe followed is the same as that

described in the standard method. Evenat present high prices manylaboratories are using the glycerol-caustic potash method for preparing thefatty acids, figuring that the saving oftime more than compensates for theextra cost of the reagents. Caustic sodacannot be substituted for caustic potashin the glycerol method.

UNSAPONIFIABLE MATTER.

The committee has consideredunsaponifiable matter to include thosesubstances frequently found dissolvedin fats and oils which are notsaponified by the caustic alkalies andwhich at the same time are soluble in

the ordinary fat solvents. The termincludes such substances as the higheralcohols, such as cholesterol which isfound in animal fats, phytosterol foundin some vegetable fats, paraffin andpetroleum oils, etc. UNSAPONIFIABLE

MATTER should not be confused in thelay mind with INSOLUBLE IMPURITIES OR


The method adopted by the committeehas been selected only after the mostcareful consideration of other methods,such as the dry extraction method andthe wet method making use of theseparatory funnel. At firstconsideration the dry extractionprocess would seem to offer the bestbasis for an unsaponifiable matter

method, but in practice it has beenfound absolutely impossible fordifferent analysts to obtain agreeingresults when using any of the dryextraction methods proposed.Therefore, this method had to beabandoned after numerous trials,although several members of thecommittee strongly favored it in thebeginning.

IODINE NUMBER—The iodine numberadopted by the committee is thatdetermined by the well-known Wijsmethod. This method was adopted aftercareful comparison with the Hanus andHübl methods. The Hübl method waseliminated from consideration almostat the beginning of the committee's

work for the reason that the timerequired for complete absorption of theiodine is unnecessarily long and, infact, even after absorption has gone onover night, it is apparently notcomplete. In the case of the Hanus andWijs methods complete absorptiontakes place in from 15 minutes to anhour, depending on conditions.Formerly, many chemists thought theHanus solution rather easier to preparethan the Wijs solution, but theexperience of the committee was thatthe Wijs solution was no more difficultto prepare than the Hanus.Furthermore, absorption of iodine fromthe Wijs solution appeared to takeplace with greater promptness and

certainty than from the Hanus and wascomplete in a shorter time. Results bythe Wijs method were also in betteragreement in the case of oils showinghigh iodine absorption than with theHanus solution and showed a slightlyhigher iodine absorption for the samelength of time. However, the differencewas not great. The committeeinvestigated the question ofsubstitution since it has been suggestedthat in case of the Wijs solutionsubstitution of iodine in the organicmolecule might occur, and found noevidence of this in the time requiredfor the determination, namely, 1/2 hr.,or even for a somewhat longer period.One member of the committee felt that

it was not desirable to introduce theWijs method into these standardmethods since the Hanus method wasalready standardized by theAssociation of Official AgriculturalChemists, but the committee felt that itmust follow the principle established atthe commencement of its work,namely, that of adopting the methodwhich appeared to be the best from allstandpoints, taking into considerationaccuracy, convenience, simplicity,time, expense, etc., without allowingprecedent to have the deciding vote.

IODINE NUMBER, TUNG OIL—Thecommittee has made an extensive studyof the application of the Wijs methodto the determination of iodine value in

the case of tung oil with the result thatit recommends the method for this oilbut has thought it desirable to limit theconditions under which thedetermination is conducted rathernarrowly, although reasonably goodresults are obtained by the committeemethod without making use of thespecial limitations.

The co-operative work of thecommittee and the specialinvestigations conducted by individualmembers bring out the followingpoints:

Influence of Temperature —From 16°C. to 30° C. there is a moderateincrease in the absorption, but above

30° the increase is rather rapid so thatit was thought best to limit thetemperature in the case of tung oil to20° to 25° C.

Influence of Time—The absorptionincreases with the time but apparentlycomplete absorption, so far asunsaturated bonds are concerned,occurs well within one hour's time.Consequently, one hour was set as thepractical limit.

Influence of Excess—The excess ofiodine solution also tends to increasethe iodine number, hence theCommittee thought it necessary tolimit the excess rather rigidly to 55 ± 3per cent, although with greater latitude

results were reasonably good.

Influence of Age of Solution—Oldsolutions tend to give low resultsalthough up to 2 mo. no greatdifferences were observed.Nevertheless, it was thought best tolimit the age of the solution to 30 days—long enough for all practicalpurposes.

Amount of Sample—As a practicalamount of sample to be weighed outthe Committee decided on 0.15 g. witha tolerance of 0.05 g. in either directionaccording to preference. In otherwords, the amount of sample to betaken for the determination to be from0.1 to 0.2 g. in the discretion of the

analyst.

The Committee's study of the Hüblmethod which has been adopted by theSociety for Testing Materials in thecase of tung oil indicates that thismethod when applied to tung oil issubject to the same influences as theWijs method and it has the additionalvery serious disadvantage of requiringa long period of time for absorptionwhich cannot be considered reasonablefor a modern analytical method. Whenusing the Hübl solution, the absorptionis not complete in the case of tung oilat 3, 7, 18 or even 24 hrs.

The Hanus method in the case of tungoil gives very high and erratic results,

as high as 180 to 240 in ordinary casesfor an oil whose true iodine number isabout 165.

MELTING POINT.

A melting point is the temperature atwhich a solid substance assumes theliquid condition. If the solid is a puresubstance in the crystalline conditionthe melting point is sharp and welldefined for any given pressure. Withincreased pressure the melting point islowered or raised, depending onwhether the substance contracts orexpands in melting. The lowering orraising of the melting point withpressure is very slight and ordinarily is

not taken into consideration. Melting-point determinations are commonlycarried out under ordinary atmosphericpressures without correction. Thegeneral effect of soluble impurities isto lower the melting point, and thisholds true whether the impurity has ahigher or lower melting point than thepure substance (solvent). Thus if asmall amount of stearic acid be addedto liquid palmitic acid and the solutionfrozen, the melting point of this solidwill be lower than that of palmitic acid.Likewise the melting point of stearicacid is lowered by the addition of asmall amount of palmitic acid. Aeutectic mixture results when twocomponents solidify simultaneously at

a definite temperature. Such a mixturehas a constant melting point andbecause of this and also because bothsolid and liquid phases have the samecomposition, eutectic mixtures wereformerly looked upon as compounds.The phenomenon of double meltingpoints has been observed in the case ofa number of glycerides. Such aglyceride when placed in the usualcapillary tube and subjected toincreasing temperature quicklyresolidifies only to melt again andremain melted at a still highertemperature. This phenomenon has notyet been sufficiently investigated toafford a satisfactory explanation.

Non-crystalline substances such as

glass, sealing wax and various otherwaxes and wax mixtures, and mostcolloidal substances do not exhibit asharp melting point, but under theapplication of heat first soften verygradually and at a considerably highertemperature melt sufficiently to flow.This phenomenon of melting through along range of temperature may be dueto the amorphous nature of thesubstance or to the fact that it consistsof a very large number of componentsof many different melting points.

The fats and oils of natural origin, thatis, the animal and vegetable fats andoils, consist of mixtures of glyceridesand, generally speaking, of aconsiderable number of such

components. These components arecrystalline and when separated in thepure state have definite melting points,although some exhibit the phenomenonof double melting point. For the mostpart the naturally occurring glyceridesare mixed glycerides. In the naturalfats and oils there are present alsocertain higher alcohols, of whichcholesterol is characteristic of theanimal fats and oils and phytosterol ofmany of the vegetable fats and oils. Inaddition to the crystalline glyceridesand the higher alcohols present inneutral fats, there are in fats of lowergrade, fatty acids, which arecrystalline, and also various non-crystalline impurities of an

unsaponifiable nature, and the presenceof these impurities tends to lower themelting point. They also tend to induceundercooling and when the liquid fat oroil is being chilled for purposes ofsolidification or in determination oftiter.

The presence of water, especially whenthis is thoroughly mixed or emulsifiedwith a fat or oil, also influences themelting point to a marked extent,causing the mixture to melt through alonger range of temperatures thanwould be the case if the water wereabsent. This is particularly true ofemulsified fats and oils, such as butterand oleomargarine, both of whichcontain, besides water, the solids

naturally present in milk or cream andincluding casein, milk sugar, and salts.The melting-point methodrecommended by the Committee is notapplicable to such emulsions or otherwatery mixtures and the Committeehas found it impossible to devise anaccurate method for making softening-point or melting-point determinationson products of this nature. Not only theamount of water present but also thefineness of its particles, that is, its stateof subdivision and distribution, in a fator oil influences the softening point ormelting point and causes it to varywidely in different samples.

As a consequence of the foregoingfacts, natural fats and oils do not

exhibit a definite melting point,composed as they are of mixtures ofvarious crystalline glycerides, higheralcohols, fatty acids, and non-crystalline substances. Therefore, theterm melting point when applied tothem requires further definition. Theyexhibit first a lower melting point (themelting point of the lowest meltingcomponent) or what might be calledthe softening point and following thisthe fat softens through a shorter orlonger range of temperature to the finalmelting point at which temperature thefat is entirely liquid. This is themelting point determined by theCommittee's melting-point method.The range between the softening point

and the final melting point variesgreatly with the different fats and oilsdepending on their chemicalcomponents, the water associated withthem, emulsification, etc. In the case ofcoconut oil the range betweensoftening point and final melting pointis rather short; in the case of butter,long. Various methods have beendevised to determine the so-calledmelting point of fats and oils. Most ofthese methods, however, determine, notthe melting point, but the softeningpoint or the flow point of the fat andthe great difficulty has been in the pastto devise a method which woulddetermine even this point withreasonable accuracy and so that results

could be easily duplicated. It has beenthe aim of the Committee to devise asimple method for the determination ofthe melting point of fats and oils, but itshould be understood that the termmelting point in the scientific sense isnot applicable to natural fats and oils.

FOOTNOTES:

[22] Approved by the SupervisoryCommittee on Standard Methods ofAnalysis of the American ChemicalSociety.

[23] Live steam must not be turnedinto tank cars or coils beforesamples are drawn, since there is nocertain way of telling when coils arefree from leaks.

[24] If there is water present underthe solid material this must be notedand estimated separately.

[25] Boiling point of water atreduced pressures.

PressureMm.Hg.

BoilingPointto 1°C.

BoilingPoint+15°C.

BoilingPoint+20°C.

100 52° C. 67° C. 72° C.90 50 65 7080 47 62 6770 45 60 6560 42 57 6250 38 53 5840 34 49 54

[26] Results comparable to those ofthe Standard Method may beobtained on most fats and oils bydrying 5-g. portions of the sample,prepared and weighed as above, toconstant weight in a well-

constructed and well-ventilated airoven held uniformly at atemperature of 105° to 110° C. Thethermometer bulb should be close tothe sample. The definition ofconstant weight is the same as forthe Standard Method.

[27] The following method issuggested by the Committee forroutine control work: Weigh out 5-to 25-g. portions of prepared sampleinto a glass or aluminum (Caution:Aluminum soap may be formed)beaker or casserole and heat on aheavy asbestos board over burner orhot plate, taking care that thetemperature of the sample does notgo above 130° C. at any time.During the heating rotate the vesselgently on the board by hand to

avoid sputtering or too rapidevolution of moisture. The properlength of time of heating is judgedby absence of rising bubbles ofsteam, by the absence of foam or byother signs known to the operator.Avoid overheating of sample asindicated by smoking or darkening.Cool in desiccator and weigh.

By co-operative work in severallaboratories, the Committee hasdemonstrated that this method canbe used and satisfactory resultsobtained on coconut oil even whena considerable percentage of freefatty acids is present, and themethod is recommended for thispurpose. Unfortunately on accountof the very great personal factorinvolved, the Committee cannot

establish this method as a preferredmethod. Nevertheless, after anoperator has learned the techniqueof the method, it gives perfectlysatisfactory results for ordinary oilsand fats, butter, oleomargarine andcoconut oil, and deserves morerecognition than it has heretoforereceived.

[28] For routine control work, filterpaper is sometimes more convenientthan the prepared Gooch crucible,but must be very carefully washed,especially around the rim, to removethe last traces of fat.

[29] For routine work, an ash maybe run on the original fat, and thesoluble mineral matter obtained bydeducting the ash on the insolubleimpurities from this. In this case the

Gooch crucible should be preparedwith an ignited asbestos mat so thatthe impurities may be ashed directlyafter being weighed. In all casesignition should be to constantweight so as to insure completedecomposition of carbonates.

[30] See note on Soluble MineralMatter following these methods.When the ash contains phosphatesthe factor 10 cannot be applied, butthe bases consisting of calciumoxide, etc., must be determined, andthe factor 10 applied to them.

[31] For routine work methyl ordenatured ethyl alcohol ofapproximately 95 per cent strengthmay be used. With these reagentsthe end-point is not sharp.

[32] P. C. McIlhiney, J. Am. Chem.Soc., 29 (1917), 1222, gives thefollowing details for the preparationof the iodine monochloridesolution:

The preparation of the iodinemonochloride solution presents nogreat difficulty, but it must be donewith care and accuracy in order toobtain satisfactory results. Theremust be in the solution no sensibleexcess either of iodine or moreparticularly of chlorine, over thatrequired to form the monochloride.This condition is most satisfactorilyattained by dissolving in the wholeof the acetic acid to be used therequisite quantity of iodine, using agentle heat to assist the solution, ifit is found necessary, setting aside a

small portion of this solution, whilepure and dry chlorine is passed intothe remainder until the halogencontent of the whole solution isdoubled. Ordinarily it will be foundthat by passing the chlorine into themain part of the solution until thecharacteristic color of free iodinehas just been discharged there willbe a slight excess of chlorine whichis corrected by the addition of therequisite amount of theunchlorinated portion until all freechlorine has been destroyed. Aslight excess of iodine does little orno harm, but excess of chlorinemust be avoided.

[33] The melting point of oils maybe determined in general accordingto the above procedure, taking into

consideration the lower temperaturerequired.

PLANT ANDMACHINERY

Illustrations of machineryand layouts of the plant of a

modern soap-makingestablishment.

Appendix

Tables marked * are takenfrom the German YearBook for Soap Industry.

(U. S. BUREAU OFSTANDARDS)

THE METRIC SYSTEM.

The fundamental unit of the metricsystem is the meter (the unit of length).From this the units of mass (gram) and

capacity (liter) are derived. All otherunits are the decimal sub-divisions ormultiples of these. These three unitsare simply related, so that for allpractical purposes the volume of onekilogram of water (one liter) is equal toone cubic decimeter.

Prefixes. Meaning. Units.

Milli- = one thousandth1-1000 .001

Meter forlength.Centi- = one hundredth

1-100 .01

Deci- = one tenth 1-10.1

Unit = one 1. Gram formass.Deka- = ten 10-1 10.

Hecto- = one hundred100-1 100. Liter for

capacity.Kilo- = one thousand

1000-1 1000.

The metric terms are formed bycombining the words "Meter," "Gram"and "Liter" with the six numericalprefixes.

LENGTH

10 milli-meters mm = 1 centi-meter c m

10 centi-meters = 1 deci-meter d

m10 deci- 1 meter (about 40

meters = inches) m

10 meters = 1 deka-meter d km

10 deka-meters = 1 hecto-meter h

m10 hecto-meters = 1 kilo-meter

(about 5/8 mile)km

MASS.

10 milli-grams. m g = 1 centi-gram c g

10 centi-grams = 1 deci-gram d g

10 deci-grams = 1 gram (about 15

grains) g

10 grams = 1 deka-gram d kg

10 Deka-grams = 1 hecto-gram h g

10 hecto-grams = 1 kilo-gram (about

2 pounds) k g

CAPACITY.

10 milli-liters. m l = 1 centi-liter c l

10 centi-liters = 1 deci-liter d l

10 deci-liters = 1 liter (about 1

quart) l

10 liters = 1 deka-liter d kl

10 deka-liters

= 1 hecto-liter (abouta barrel)

h l

10 hecto-liters = 1 kilo-liter k l

The square and cubic units are thesquares and cubes of the linear units.

The ordinary unit of land area is theHectare (about 2-1/2 acres).

U.S. BUREAU OFSTANDARDS TABLE OFMETRIC EQUIVALENTS

Meter = 39.37 inches.

Legal Equivalent Adopted by Act of

Congress July 28, 1866.

LENGTH.

Centimeter = 0.3937 inchMeter = 3.28 feetMeter = 1.094 yardsKilometer = 0.621 statute mileKilometer = 0.5396 nautical mileInch = 2.540 centimetersFoot = 0.305 meterYard = 0.914 meterStatute mile = 1.61 kilometersNautical mile = 1.853 kilometers

AREA.

Sq. centimeter = 0.155 sq. inchSq. meter = 10.76 sq. feetSq. meter = 1.196 sq. yardsHectare = 2.47 acresSq. kilometer = 0.386 sq. mileSq. inch = 6.45 sq. centimetersSq. foot = 0.0929 sq. meterSq. yard = 0.836 sq. meterAcre = 0.405 hectareSq. mile = 2.59 sq. kilometers

WEIGHT.

Gram = 15.43 grains

Gram = 0.772 U. S. apoth.scruple

Gram = 0.2572 U. S. apoth.dram

Gram = 0.0353 avoir. ounceGram = 0.03215 troy ounceKilogram = 2.205 avoir. poundsKilogram = 2.679 troy pounds

Metric ton = 0.984 gross or longton

Metric ton = 1.102 short or nettons

Grain = 0.064 gramU. S. apoth.scruple = 1.296 grams

U. S. apoth.dram = 3.89 grams

Avoir. ounce = 28.35 grams

Troy ounce = 31.10 gramsAvoir. pound = 0.4536 kilogramTroy pound = 0.373 kilogramGross or longton = 1.016 metric tons

Short or net ton = 0.907 metric ton

VOLUME.

Cu. centimeter = 0.0610 cu. inchCu. meter = 35.3 cu. feetCu. meter = 1.308 cu. yardsCu. inch = 16.39 cu. centimetersCu. foot = 0.283 cu. meterCu. yard = 0.765 cu. meter

CAPACITY.

Millimeter = 0.0338 U. S. liq.ounce

Millimeter = 0.2705 U. S. apoth.dram

Liter = 1.057 U. S. liq.quarts

Liter = 0.2642 U. S. liq.gallon

Liter = 0.908 U. S. dry quartDekaliter = 1.135 U. S. pecksHectoliter = 2.838 U. S. bushelsU. S. liq.ounce = 29.57 millimeters

U. S. apoth.dram

= 3.70 millimeters

U. S. liq.quarts = 0.946 liter

U. S. dryquarts = 1.101 liters

U. S. liq.gallon = 3.785 liters

U. S. peck = 0.881 dekaliterU. S. bushel = 0.3524 hectoliter

AVOIRDUPOIS WEIGHT.

1 pound = 16 ounces = 256 drams 1 ounce = 16 "

TROY (APOTHECARIES')WEIGHT (U. S.)

1pound = 12

ounces= 96drams

= 288scruples

= 5,760grains

1ounce

= 8drams

= 24scruples

= 480grains

1dram

= 3scruples

= 60grains

1scruple

= 20grains

WINE (APOTHECARIES) LIQUIDMEASURE (U. S.)

1gallon

= 8pints

= 128fl. ozs.

= 1,024fl. drams

= 61,440minims

1pint

= 16fl. ozs.

= 128 fl.drams

= 7,689minims

1 fl.oz.

= 8 fl.drams

= 480minims

1 fl.dram

= 60minims

To find diameter of a circle multiplycircumference by .31831.

To find circumference of a circle ,multiply diameter by 3.1416.

To find area of a circle , multiplysquare of diameter by .7854.

To find surface of a ball , multiplysquare of diameter by 3.1416.

To find side of an equal square ,multiply diameter by .8862.

To find cubic inches in a ball , multiplycube of diameter by .5236.

Doubling the diameter of a pipe,increases its capacity four times.

One cubic foot of anthracite coalweighs about 53 lbs.

One cubic foot of bituminous coalweighs from 47 to 50 pounds.

A gallon of water (U. S. standard)weighs 8-1/3 pounds and contains 231cubic inches.

A cubic foot of water contains 7-1/2gallons, 1728 cubic inches and weighs62-1/2 pounds.

To find the number of pounds of watera cylindrical tank contains, square thediameter, multiply by .785 and then bythe height in feet. This gives thenumber of cubic feet which multipliedby 62-1/2 gives the capacity in poundsof water. Divide by 7-1/2 and this givesthe capacity in gallons.

A horse-power is equivalent to raising33,000 pounds 1 foot per minute, or550 pounds 1 foot per second.

The friction of water in pipes is as thesquare of velocity. The capacity ofpipes is as the square of theirdiameters; thus, doubling the diameterof a pipe increases its capacity fourtimes.

To find the diameter of a pump cylinderto move a given quantity of water perminute (100 feet of piston being thestandard of speed), divide the numberof gallons by 4, then extract the squareroot, and the product will be thediameter in inches of the pumpcylinder.

To find the horse-power necessary toelevate water to a given height,multiply the weight of the waterelevated per minute in pounds by theheight in feet, and divide the productby 33,000 (an allowance should beadded for water friction, and a furtherallowance for loss in steam cylinder,say from 20 to 30 per cent).

To compute the capacity of pumpingengines, multiply the area of waterpiston, in inches, by the distance ittravels, in inches, in a given time.Deduct 3 per cent for slip and roddisplacement. The product divided by231 gives the number of gallons intime named.

To find the velocity in feet per minutenecessary to discharge a given volumeof water in a given time, multiply thenumber of cubic feet of water by 144and divide the product by the area ofthe pipe in inches.

To find the area of a required pipe , thevolume and velocity of water beinggiven, multiply the number of cubic

feet of water by 144 and divide theproduct by the velocity in feet perminute. The area being found, thediameter can be learned by using anytable giving the "area of circles" andfinding the nearest area, opposite towhich will be found the diameter tocorrespond.

Physical and ChemicalConstants of Fixed Oils and

Fats.

(FROM LEWKOWITSCH AND OTHER

AUTHORITIES.)

Specific

Specificgravityat 15°C.

gravityat100°C.

Melting-point. C.

Linseed oil 0.931-0.938 0.880 -16° to

-26°

Hemp-seed oil 0.925-0.931

Walnut oil 0.925-0.926 0.871

Poppy-seed oil 0.924-0.927 0.873

Sunflower oil 0.924-0.926 0.919

Fir-seed oil 0.925-0.9280.921-

Maize oil 0.926

Cotton-seedoil

0.922-0.930 0.867

Sesame oil 0.923-0.924 0.871

Rape-seed oil 0.914-0.917 0.863

Black mustardoil

0.916-0.920

Croton oil 0.942-0.955

Castor oil 0.960-0.966 0.910

Apricot-kerneloil

0.915-0.919

Almond oil 0.915-0.920

Peanut(arachis) oil

0.916-0.920 0.867

Olive oil 0.914-0.917 0.862

Menhaden oil 0.927-0.933

Cod-liver oil 0.922-0.927 0.874

Seal oil 0.924-0.929 0.873

Whale oil 0.920-0.930 0.872

Dolphin oil 0.917-0.918

Porpoise oil 0.926 0.871

Neat's-foot oil0.914-0.916 0.861

Cotton-seedstearine

0.919-0.923 0.867 40°

Palm oil 0.921-0.925 0.856 27° to

42°

Cacao butter 0.950-0.952 0.858 30° to

33°

Cocoa-nut oil 0.925-0.926 0.873 20° to

26°

Myrtle wax 0.995 0.875 40° to44°

Japan wax 0.970-0.980 0.875 51° to

54.5°

Lard 0.931-0.938

0.861 41° to46°

Bone fat 0.914-0.916

21° to22°

Tallow0.943-0.952 0.860

42° to46°

Butter fat 0.927-0.936 0.866 29.5° to

33°

Oleomargarine 0.924-0.930 0.859

Sperm oil 0.875-0.884 0.833

Bottle-nose oil 0.879-0.880 0.827

Carnauba wax 0.990-0.999 0.842 84° to

85°

Wool-fat 0.973 0.901 39° to42°

Beeswax 0.958-0.969 0.822 62° to

64°

Spermaceti 0.960 0.81243.5° to49°

Chinese wax 0.970 0.810 80.5° to81°

Tung (Chinesewood oil)

0.936-0.942

Soya-bean oil 0.924-0.927

Physical and ChemicalConstants of Fixed Oils and

Fats.

(FROM LEWKOWITSCH AND OTHER

AUTHORITIES.)

Saponificationvalue.

Maumenétest.

Linseed oil 190-195 104°-111°

Hemp-seed oil 190-193 95°-96°

Walnut oil 195 96°-101°

Poppy-seed oil 195 86°-88°

Sunflower oil 193-194 72°-75°

Fir-seed oil 191.3 98°-99°

Maize oil 188-193 56°-60.5°

Cotton-seedoil 191-195 68°-77°

Sesame oil 189-193 64°-68°

Rape-seed oil 170-178 51°-60°

Black mustardoil 174-174.6 43°-44°

Croton oil 210.3-215

Castor oil 178-186 46°-47°

Apricot-kernel

oil 192.2-193.1 42.5°-46°

Almond oil 190.5-195.4 51°-54°Peanut(arachis) oil 190-197 45°-49°

Olive oil 191-196 41.5°-45.5°

Menhaden oil 189.3-192 123°-128°

Cod-liver oil 182-187 102°-103°

Seal oil 190-196 92°

Whale-oil 188-193 91°-92°

Dolphin{Body oil 197.3

oil {Jaw oil 200Porpoise{Body oil

216-218.8 50°

oil {Jaw oil 253.7

Neat's-foot oil 194.3 47°-48.5°

Cotton-seedstearine. 194.6-195.1 48°

Palm oil 196.3-202Cacao butter 192.2-193.5

Cocoa-nut oil 250-253

Myrtle wax 205.7-211.7

Japan wax 220-222.4

Lard 195.3-196.6 27°-32°

Bone fat 190.9

Tallow 195-198

Butter fat 221.5-227

Oleomargarine 194-203.7

Sperm oil 132.5-147 47°-51°

Bottle-nose oil 126-134 41°-47°

Carnauba wax 80-84Wool-fat 98.2-102.4Beeswax 91-96Spermaceti 128Chinese wax 63Tung (Chinese 193

wood oil)

Soya-bean oil 190.6-192.9 59°-61°

*Temperature CorrectionTable for Hehner's

Concentrated BichromateSolution for Glycerine

Analysis

ATemperature

f CorrectedVolume 1c.c.

Logarithm

11° C 0.9980 ccm 9991312° " 0.9985 " 9993513° " 0.9990 " 9995614° " 0.9995 " 9997815° " 1.0000 " 0000016° " 1.0005 " 0002217° " 1.0010 " 0004318° " 1.0015 " 0006519° " 1.0020 " 0008720° " 1.0025 " 0010821° " 1.0030 " 0013022° " 1.0035 " 00152

23° " 1.0040 " 00173

*Table of Important FattyAcids

Boiling Point

Name Formula Mol.Wt.

OrdinaryPressure

100 mmPressure

Butyric C4H8O2 88 162.3

Caproic C6H12O2 116 199.7

Caprylic C8H16O2 144 236-237

Capric C10H20O2 172 268-270 199.5-200

Lauric C12H24O2 200 225

Myristic C14H28O2 228 250.5

Palmitic C16H32O2 256 268.5

Stearic C18H36O2 284 291

Arachidic C20H40O2 302

Behenic C22H44O2 330

Cerotic C27H54O2 400

Melissic C30H60O2 442

Oleic C18H34O2 282 185.5-286

Erucic C22H42O2 338

Linolic C18H32O2 280

Linolenic C18H30O2 278

Ricinoleic C18H34O3 298

*Comparison ofThermometer Scales

n Degree Celsius = 4/5n DegreeReaumur = 32 + 9/5n DegreeFahrenheit

n Degree Reaumur = 5/4n DegreeCelsius = 32 + 9/4n Degree Fahrenheit

n Degree Fahrenheit = 5/9 (n - 32)Degree Celsius = 4/9 (n - 32) Deg. R

C. R. F. C. R. F. C. R.-20 -16 -4 20 16 68 60 48-19 -15.2 -2.2 21 16.8 69.8 61 48.8-18 -14.4 -0.4 22 17.6 71.6 62 49.6

-17 -13.6 1.4 23 18.4 73.4 63 50.4-16 -12.8 3.2 24 19.2 75.2 64 51.2-15 -12 5 25 20 77 65 52-14 -11.2 6.8 26 20.8 78.8 66 52.8-13 -10.4 8.6 27 21.6 80.6 67 53.6-12 -9.6 10.4 28 22.4 82.4 68 54.4-11 -8.8 12.2 29 23.2 84.2 69 55.2-10 -8 14 30 24 86 70 56-9 -7.2 15.8 31 24.8 87.8 71 56.8-8 -6.4 17.6 32 25.6 89.6 72 57.6-7 -5.6 19.4 33 26.4 91.4 73 58.4-6 -4.8 21.2 34 27.2 93.2 74 59.2-5 -4 23 35 28 95 75 60-4 -3.2 24.8 36 28.8 96.8 76 60.8-3 -2.4 26.6 37 29.6 98.6 77 61.6

-2 -1.6 28.4 38 30.4 100.4 78 62.4

-1 -0.8 30.2 39 31.2 102.2 79 63.20 0 32 40 32 104 80 641 0.8 33.8 41 32.8 105.8 81 64.82 1.6 35.6 42 33.6 107.6 82 65.63 2.4 37.4 43 34.4 109.4 83 66.44 3.2 39.2 44 35.2 111.2 84 67.25 4 41 45 36 113 85 686 4.8 42.8 46 36.8 114.8 86 68.87 5.6 44.6 47 37.6 116.6 87 69.68 6.4 46.4 48 38.4 118.4 88 70.49 7.2 48.2 49 39.2 120.2 89 71.210 8 50 50 40 122 90 7211 8.8 51.8 51 40.8 123.8 91 72.8

12 9.6 53.6 52 41.6 125.6 92 73.613 10.4 55.4 53 42.4 127.4 93 74.4

14 11.2 57.2 54 43.2 129.2 94 75.215 12 59 55 44 131 95 7616 12.8 60.8 56 44.8 132.8 96 76.817 13.6 62.6 57 45.6 134.6 97 77.618 14.4 64.4 58 46.4 136.4 98 78.419 15.2 66.2 59 47.2 138.2 99 79.2

*Quantities of AlkaliRequired for Saponification

of Fats of AverageMolecular Weight 670

(Cocoanut Oil, Palmkernel Oil)

KilosLiters AlkaliSolution Sp. Gr.1.1

Liters AlkaliSolution Sp. Gr.1.2

NaOH KOH NaOH KOH1000 1875.83 1902.99 844.67 930.352000 3751.66 3805.97 1689.35 1860.703000 5627.50 5708.96 2534.02 2791.044000 7508.33 7611.94 3378.69 3721.395000 9379.16 9514.93 4223.37 4651.746000 11254.99 11417.91 5068.04 5582.097000 13130.82 13320.90 5912.71 6512.448000 15006.66 15223.88 6757.38 7442.789000 16882.49 17126.87 7602.06 8373.13

10000 18758.32 19029.85 8446.73 9303.48

*Quantities of AlkaliRequired for Saponification

of Fats of AverageMolecular Weight 860

(Tallow, Cottonseed Oil, Olive Oil,Etc.)

KilosLiters AlkaliSolution Sp. Gr.1.1

Liters AlkaliSolution Sp. Gr.1.2

NaOH KOH NaOH KOH1000 1461.40 1482.56 658.05 724.81

2000 2922.81 2965.12 1316.12 1449.613000 4384.21 4447.67 1974.18 2174.424000 5845.62 5930.23 2632.24 2899.225000 7307.02 7412.79 3290.80 3624.036000 8768.42 8895.85 3948.35 4348.847000 10229.83 10377.91 4606.41 5073.648000 11691.23 11860.45 5264.47 5798.459000 13152.64 13343.02 5922.53 6523.2510000 14614.04 14825.58 6580.59 7248.06

DENSITY ANDSTRENGTH OF

SULPHURIC ACID(SIDERSKY).

DegreesTwaddell.

Sp.Gr.at15°C.

% ofpureacid(H2SO4).

Equivalent(in cc.) ofa kilo ofpure acid.

Equivalent(in cc.) ofa liter ofpure acid.

1 1.007 1.9 52.620 96.9303 1.014 2.8 35.710 66.4504 1.022 3.8 25.650 47.2306 1.029 4.8 20.410 37.5828 1.037 5.8 16.670 30.6909 1.045 6.8 14.085 25.93810 1.052 7.8 12.198 22.46012 1.062 8.8 10.755 19.80313 1.067 9.8 9.524 17.54015 1.075 10.9 8.547 15.740

17 1.083 11.9 7.752 14.27818 1.091 13.0 7.042 12.96920 1.100 14.1 6.452 11.88222 1.108 15.2 5.953 10.96223 1.116 16.2 5.526 10.17725 1.125 17.3 5.405 9.95427 1.134 18.5 4.76 8.77029 1.142 19.6 4.465 8.22330 1.152 20.8 4.184 7.72332 1.162 22.2 3.876 7.13834 1.171 23.3 3.663 6.74536 1.180 24.5 3.541 6.52138 1.190 25.8 3.258 5.99940 1.200 27.1 3.077 5.66642 1.210 28.4 2.907 5.353

44 1.220 29.6 2.770 5.102

46 1.231 31.0 2.618 4.86548 1.241 32.2 2.500 4.60450 1.252 33.4 2.392 4.40653 1.263 34.7 2.283 4.20555 1.274 36.0 2.179 4.01257 1.285 37.4 2.079 3.82960 1.297 38.8 1.988 3.66162 1.308 40.2 1.905 3.50864 1.320 41.6 1.821 3.35466 1.332 43.0 1.745 3.21469 1.345 44.4 1.665 3.08571 1.357 45.5 1.621 2.98574 1.370 46.9 1.558 2.869

77 1.383 48.3 1.497 2.75780 1.397 49.8 1.436 2.646

82 1.410 51.2 1.386 2.55185 1.424 52.6 1.335 2.45988 1.438 54.0 1.287 2.37091 1.453 55.4 1.237 2.27094 1.468 56.9 1.195 2.20097 1.483 58.3 1.156 2.130100 1.498 59.6 1.116 2.050103 1.514 61.0 1.080 1.980106 1.530 62.5 1.045 1.930108 1.540 64.0 1.010 1.860113 1.563 65.5 0.975 1.800116 1.580 67.0 0.950 1.740

120 1.597 68.6 0.917 1.690123 1.615 70.0 0.888 1.630127 1.634 71.6 0.855 1.570130 1.652 73.2 0.845 1.520134 1.671 74.7 0.800 1.470138 1.691 76.4 0.774 1.430142 1.711 78.1 0.749 1.390146 1.732 79.9 0.722 1.320151 1.753 81.7 0.705 1.280155 1.774 84.1 0.672 1.235160 1.798 86.5 0.639 1.190164 1.819 89.7 0.609 1.120168 1.842 100.0 0.544 1.000

*Densities of PotassiumCarbonate Solutions at 15 C

(Gerlach)

Sp. Gr.Per cent ofpure K2CO3

1.00914 11.01829 21.02743 31.03658 41.04572 51.05513 61.06454 71.07396 8

1.08337 91.09278 101.10258 111.11238 121.12219 131.13199 141.14179 151.15200 161.16222 171.17243 181.18265 191.19286 201.20344 211.21402 221.22459 23

1.23517 24

1.24575 251.25681 261.26787 271.27893 281.28999 291.30105 301.31261 311.32417 321.33573 331.34729 341.35885 351.37082 361.38279 37

1.39476 381.40673 39

1.41870 401.43104 411.44338 421.45573 431.46807 441.48041 451.49314 461.50588 471.51861 481.53135 491.54408 501.55728 51

1.57048 521.57079 53.024

*Constants of Certain FattyAcids and Triglycerides

Triglyceridesof

Per cent YieldMol.Wt.ofFattyAcid

Mol. Wt.ofTriglycerides

FattyAcid

Stearic Acid 284 890 95.73Oleic Acid 282 884 95.70MargaricAcid 270 848 95.52

PalmiticAcid 256 806 95.28

MyristicAcid 228 722 94.47

Lauric Acid 200 638 94.04Capric Acid 172 594 93.14Caproic Acid 116 386 90.16Butyric Acid 88 302 87.41

PERCENTAGES OFSOLID CAUSTIC SODAAND CAUSTIC POTASH

IN CAUSTIC LYESACCORDING TO BAUME

SCALE.

Degrees Baumé. % NaOH % KOH1 0.61 0.902 0.93 1.703 2.00 2.604 2.71 3.505 3.35 4.506 4.00 5.607 4.556 6.2868 5.29 7.409 5.87 8.2010 6.55 9.2011 7.31 10.10

12 8.00 10.9013 8.68 12.0014 9.42 12.9015 10.06 13.8016 10.97 14.8017 11.84 15.7018 12.64 16.5019 13.55 17.6020 14.37 18.6021 15.13 19.5022 15.91 20.5023 16.77 21.4024 17.67 22.5025 18.58 23.3026 19.58 24.20

27 20.59 25.10

28 21.42 26.1029 22.64 27.0030 23.67 28.0031 24.81 28.9032 25.80 29.8033 26.83 30.7034 27.80 31.8035 28.83 32.7036 29.93 33.7037 31.22 34.9038 32.47 35.9039 33.69 36.9040 34.96 37.80

41 36.25 38.9042 37.53 39.90

43 38.80 40.9044 39.99 42.1045 41.41 43.4046 42.83 44.6047 44.38 45.8048 46.15 47.1049 47.58 48.2550 49.02 49.40

GLYCERINE CONTENTOF MORE COMMON

OILS AND FATS USED IN

SOAP MAKING.

Kind.

TheoreticalYieldof PureGlycerineof NeutralOil or Fat.

AverageFree FattyAcidinCommercialOil.

% PureGlycerineinCommercialOil.

BeefTallow 10.7 5 10.2

BoneGrease 10.5 20-50 5.2- 8.4

Castor Oil 9.8 0.5-10 8.8- 9.8

CocoanutOil 13.9 3-5 13.2-13.5

CocoanutOil Off 15-40 8.3-11.8 10.37-14.75

Corn Oil 10.4 1-10 9.3-10.3

CottonseedOil 10.6 Trace 10.6

HogGrease 10.6 0.5-1 10.5-10.6

HorseGrease 10.6 1-3 10.5-10.6

Olive Oil 10.3 2-25 7.7-10.2

OliveFoots 30-60 4-7 5- 8.75

Palm Oil 11.0 10-50 5.5-10PalmkernelOil 13.3 4-8 12.2-12.8

Peanut Oil 10.4 5-20 8.3- 9.9

Soya BeanOil 10.4 2 10.2

Train Oil 10.0 2-20 8- 9.8

VegetableTallow 10.9 1-3 10.5-10.8

*Table of Specific Gravitiesof Pure Commercial

Glycerine withCorresponding Percentageof Water. Temperature 15

C.

Sp. Gr. % Water Sp. Gr. % Water1.262 0 1.160 381.261 1 1.157 391.258 2 1.155 401.255 3 1.152 411.2515 4 1.149 421.250 5 1.1464 431.2467 6 1.1437 441.2450 7 1.141 451.243 8 1.1377 461.241 9 1.1353 471.237 10 1.1326 481.235 11 1.1304 491.2324 12 1.127 501.229 13 1.125 51

1.2265 14 1.1224 521.2245 15 1.1204 531.2225 16 1.117 541.2185 17 1.114 551.2174 18 1.112 561.2142 19 1.109 571.211 20 1.106 581.207 21 1.103 591.203 22 1.1006 601.2004 23 1.088 651.198 24 1.075 701.195 25 1.0623 751.1923 26 1.049 801.189 27 1.0365 85

1.188 28 1.0243 901.1846 29 1.0218 911.182 30 1.0192 921.179 31 1.0168 931.176 32 1.0147 941.1734 33 1.0125 951.171 34 1.01 961.168 35 1.0074 971.165 36 1.0053 981.163 37 1.0026 99

Table of Percentage,Specific Gravity and

Beaume Degree of Pure

Glycerine Solutions

PercentWater

Sp. Gr.Championand Pellet

DegreeBeaumé(Berthelot)

PercentWater

Sp. Gr.Championand Pellet

0 1.2640 31.2 11.0 1.23500.5 1.2625 31.0 11.5 1.23351.0 1.2612 30.9 12.0 1.23221.5 1.2600 30.8 12.5 1.23072.0 1.2585 30.7 13.0 1.22952.5 1.2575 30.6 13.5 1.22803.0 1.2560 30.4 14.0 1.22703.5 1.2545 30.3 14.5 1.22554.0 1.2532 30.2 15.0 1.22424.5 1.2520 30.1 15.5 1.2230

5.0 1.2505 30.0 16.0 1.22175.5 1.2490 29.9 16.5 1.22026.0 1.2480 29.8 17.0 1.21906.5 1.2465 29.7 17.5 1.21777.0 1.2455 29.6 18.0 1.21657.5 1.2440 29.5 18.5 1.21508.0 1.2427 29.3 19.0 1.21378.5 1.2412 29.2 19.5 1.21259.0 1.2400 29.0 20.0 1.21129.5 1.2390 28.9 20.5 1.210010.0 1.2375 28.8 21.0 1.208510.5 1.2362 28.7

*Table of Specific Gravities

of Pure Glycerine Solutionswith Corresponding BeaumeDegree and Percent Water

PercentWater

Sp.Gr.

DegreeBeaume

PercentWater

Sp.Gr.

DegreeBeaume

0.0 1.2640 31.2 1.0 1.2612 30.90.5 1.2625 31.0 1.5 1.2600 30.82.0 1.2585 30.7 12.0 1.2322 28.32.5 1.2575 30.6 12.5 1.2307 28.23.0 1.2560 30.4 13.0 1.2295 28.03.5 1.2545 30.3 13.5 1.2280 27.84.0 1.2532 30.2 14.0 1.2270 27.74.5 1.2520 30.1 14.5 1.2255 27.6

5.0 1.2505 30.0 15.0 1.2242 27.45.5 1.2490 29.9 15.5 1.2230 27.36.0 1.2480 29.8 16.0 1.2217 27.26.5 1.2465 29.7 16.5 1.2202 27.07.0 1.2455 29.6 17.0 1.2190 26.97.5 1.2440 29.5 17.5 1.2177 26.88.0 1.2427 29.3 18.0 1.2165 26.78.5 1.2412 29.2 18.5 1.2150 26.59.0 1.2400 29.0 19.0 1.2137 26.49.5 1.2390 28.9 19.5 1.2125 26.310.0 1.2375 28.8 20.0 1.2112 26.210.5 1.2362 28.7 20.5 1.2100 26.011.0 1.2350 28.6 21.0 1.2085 25.911.5 1.2335 28.4

INDEXA

Acetin process for the determination ofglycerol, 155.

Acid, Clupanodonic, 20.

Acid, Hydrochloric, 111.

Acid, Lauric, 2.

Acid, Myristic, 2.

Acid, Napthenic, 24.

Acid, Oleic, 15, 19.

Acid, Palmitic, 2.

Acid, Pinic, 22.

Acid, Resin, 144.

Acid, Stearic, 15, 19.

Acid, Sulfuric, 112.

Acid, Sylvic, 22.

Acid saponification, 120.

Air bleaching of palm oil, 12.

Albuminous matter, Removal fromtallow, 6.

Alcohol, Denatured, 82.

Alcoholic method for free alkali insoap, 139.

Alkali Blue 6 B, indicator, 129.

Alkali, Total, determination of in soap,147.

Alkalis, 25.

Alkalis used in soap making,Testing of, 134.

Amalgamator, 33.

Analysis, Glycerine, International, 150.

Analysis, Soap, 137.

Analysis, Standard methods for fatsand oils, 165-196.

Aqueous saponification, 121.

Arachis oil, 79.

Autoclave saponification, 118.

Automobile soaps, 41.

B

Barrels, sampling, 168.

Baumé scale, 25.

Bayberry wax, Use in shaving soap, 89.

Bichromate Process for glyceroldetermination, 160.

Bleaching, Fullers' earth process fortallow, 4.

Bleaching palm oil by bichromatemethod, 9.

Bleaching palm oil by air, 12.

Bosshard & Huggenberg method fordetermination of free alkali, 140.

Bunching of soap, 52.

C

Candelite, 96.

Candle tar, 125.

Carbolic soap, 77.

Carbon Dioxide, Formation of incarbonate saponification, 45.

Carbonate, potassium, 29.

Carbonate, saponification, 35, 45.

Carbonate, sodium, 28.

Castile soap, 79.

Castor oil ferment, 121.

Castor oil, Use of in transparent soaps,83.

Caustic potash, 26.

Caustic potash, Electrolytic, 27.

Caustic soda, 26.

Changes in soap-making, 36.

Chemist, Importance of, 127.

Chipper, Soap, 32.

Chip soap, 54.

Chip soap, Cold made, 55.

Chip soap, Unfilled, 56.

Chrome bleaching of palm oil, 9.

Cloud test for oil, Standard method,182-183.

Clupanodonic acid, 20.

Cocoanut oil, 6.

Cold cream soap, 78.

Cold made chip soaps, 55.

Cold made toilet soaps, 72.

Cold made transparent soaps, 84.

Cold process, 35, 43.

Colophony, 22.

Coloring soap, 75.

Copra, 7.

Corn oil, 14.

Corrosive sublimate, 78.

Cotton goods. Soaps used for, 103.

Cottonseed oil, 14.

Cream, Shaving, 90.

Crude glycerine, 113.

Crutcher, 32.

Curd soap, 71.

Cutting table, 32.

D

Determination of free fatty acid, 128.

Determination of unsaponifiablematter, 132.

Distillation of fatty acids, 125.

Drying machine, 32.

E

Enzymes, 17.

Eschweger soap, 81.

Examination of fats and oils, 128.

F

Fahrion's method for moisture, 138.

Fats and oils, Examination of, 128.

Fats and oils used in soap manufacture,3.

Fatty acids, 14.

Fatty acids, Distillation of, 125.

Ferments, Splitting fats with, 121.

Fillers for laundry soaps, 53.

Fillers for soap powders, 58.

Finishing change, 36.

Fish oils, 20.

Floating soap, 62.

Formaldehyde soap, 78.

Frames, 31.

Free alkali in soap, Determination of,139.

Free fatty acid, Determination of, 128.

Free fatty acids, Extraction fromtallow, 6.

Free fatty acid, Standard method ofdilu., 174.

Note on method, 188-189.

Full boiled soaps, 35.

Fullers' earth bleaching of tallow, 4.

G

Glycerides, 2.

Glycerine, 2.

Glycerine analysis, 150.

Glycerine change, 36.

Glycerine, Crude, 113.

Glycerine in spent lyes, Recovery of,106.

Glycerine in soap, Determination of,149.

Glycerine, Sampling crude, 162.

Glycerine soaps, 83.

Glycerol content, Ways of calculatingactual, 159.

Glycerol determination, Acetinprocess, 155.

Glycerol determination, Bichromateprocess for, 160.

Graining soap, 30.

Grease, 21.

Grease, Bleaching, 21.

Grinding soap, 34.

H

Hand Paste, 93.

Hard water, 29.

Hardened oils in toilet soap, Use of, 96.

Hydrocarbon oils, 2.

Hydrogenating oils, 19.

Hydrolysis of fats and oils, 17.

Hydrolytic dissociation of soap, 1.

Hydrometers, 25.

I

Indicators, Action, 135-6.

Insoluble impurities in fatty oils,Determination of (standard method)172.

Note on method 187.

Insoluble matter in soap, determinationof, 143.

International committee on glycerineanalysis, 150.

Iodine manufacturing oil, 191.

Iodine member Wijs method, Standard,177-181. Note on method, 191.

Iodine soap, 78.

J

Joslin, ref., 113.

K

"Killing" change, 36.

Koettstorfer number (Standardmethod), 181-182.

Kontakt reagent, 117.

Krebitz Process, 123.

Krutolin, 96.

L

Leiste & Stiepel method for rosin insoap, 146.

Liebermann, Storch reaction, 144.

Light powders, 60.

Laundry soap, 48.

LeBlanc Process, 28.

Lewkowitsch, ref., 17, 146.

Lime saponification, 118.

Lime, Use in Krebitz Process, 123.

Lime, Use in treatment of glycerinewater, 116.

Liquid medicinal soaps, 79.

Liquid soaps, 94.

Lyes, Spent, 37.

M

Magnesia, Use in autoclavesaponification, 120.

Manganese sulfate, Use of as catalyzerin fermentative cleavage of fats, 122.

Marine soaps, 39.

Medicinal soaps, 76.

Medicinal soaps, Less important, 78.

Medicinal soaps, Therapeutic value of,

76.

Melting point of fat or oil, Standardmethod, 193.

Mercury soaps, 78.

Metallic soaps, 1.

Methyl orange, indicator, 136.

Meyerheim, ref., 21.

Mill soap, 32.

Moisture in soap, Determination of,138, 130.

Moisture and volatile matter in fats andoils, Standard method for detm. of,170.


Mottle in soap, 81.

Mug shaving soap, 90.

N

Naphtha, Incorporation in soap, 49.

Naphthenic acids, 24.

Nigre, 36.

Normal acids, Equivalent in alkalis,136.

O

Oils and fats, 1.

Oils and fats, Chemical constants, 18.

Oils and fats, Distinction, 1.

Oils and fats, Preserving, 18.

Oils and fat, Nature of used in soapmanufacture, 2.

Oils and fats, Rancidity of, 16.

Oil hardening, 19.

Oleic acid, 15, 19.

Olein, 2, 19.

Olive oil, 14.

Olive oil foots, 14.

Organoleptic methods, 127.

P

Palmatin, 2.

Palm kernel oil, 8.

Palmitic acid, 2.

Palm oil, 8.

Palm oil, air bleaching, 12.

Palm oil, Chrome bleaching of, 9.

Palm oil soap, 66.

Pearl ash, 29.

Perfuming and coloring toilet soaps,73.

Peroxide soap, 78.

Petroff reagent, 117.

Pfeilring reagent, 117.

Phenol, 77.

Phenolphthalein, indicator, 38.

Phenolphthalein, Using as indicator,51.

Phenols, Soaps containing, 77.

Pinic acid, 22.

Plodder, 33.

Potash from wood ash, 27.

Potassium carbonate, 29.

Powders, Light, 60.

Powders, Scouring, 61.

Powders, Shaving, 90.

Powders, Soap, 56.

Precipitation test for treated spent lyes,110.

Prevention of rancidity, 18.

Pumice or sand soaps, 93.

Purple shade in soap, 75.

R

Rancidity of oils and fats, 16.

Rancidity, Prevention, 18.

Recovery of glycerine from spent lye,106.

Red oil, 15.

Red oil, Saponified, 15.

Resin acids, Total fatty and,

Determination of in soap, 144.

Ribot, ref., 20.

Rosin, 22.

Rosin, Determination of in soap, 144.

Rosin saponification, 23.

Run and glued up soaps, 69.

Run soaps, 39.

S

Sal soda, 29.

Salt, 30.

Salting out, 30.

Salt "pickle," 37.

Sampling crude glycerine, 162.

Sampling for standard method, 166.Note on, 184.

Sampling oils and fats, 128.

Sampling soap, 137.

Saponification by ferments, 121.

Saponification, Acid, 120.

Saponification, Aqueous, 121.

Saponification, Autoclave, 118.

Saponification, Carbonate, 45.

Saponification defined, 2, 105.

Saponification, Lime, 118.

Saponification number, 181-182.

Saponification, Rosin, 23.

Saponification, Various methods, 105.

Scouring and fulling soaps for wool,98.

Scouring powders, 61.

Scouring soap, 61.

Semi-boiled laundry soaps, 49.

Semi-boiled process, 44.

Shaving cream, 90.

Shaving powder, 90.

Shaving soaps, 87.

Silica and silicates, Determination of

in soap, 148.

Silk dyeing, 102.

Silk industry, Soaps used in, 101.

Slabber, 32.

Smith method for moisture in soap,138.

Soap analysis, 137.

Soap, Automobile, 41.

Soap, Carbolic, 71.

Soap, Castile, 79.

Soap, Chip, 54.

Soap Chip, cold made, 55.

Soap, Chip, unfilled, 56.

Soap, Cold cream, 78.

Soap, Coloring, 75.

Soap containing phenols, 77.

Soap, Curd, 71.

Soap, Defined, 1.

Soap, Determination insoluble matter,

143.

Soap, Determining glycerine in, 149.

Soap, Eschweger, 81.

Soap, Floating, 62.

Soap, Formaldehyde, 78.

Soap for wool, Scouring and fulling,98.

Soap, Full boiled, 35.

Soap, Iodine, 78.

Soap kettle, 31.

Soap, Laundry, 48.

Soap, Liquid, 94.

Soap lye crude glycerine, 113.

Soap, Marine, 39.

Soap, Medicinal, 76.

Soap, Medicinal, less important, 78.

Soap, Mercury, 78.

Soap, Metallic, 1.

Soap, Peroxide, 78.

Soap powders, 56.

Soap, Pumice or sand, 93.

Soap, Rosin settled, 50.

Soap, Run and glued up, 69.

Soap, Scouring, 61.

Soap, Semi-boiled laundry, 49.

Soap, Shaving, 87.

Soap, Sulphur, 77.

Soap, Tannin, 78.

Soap, Tar, 77.

Soap, Test for color of, 133.

Soap, Textile, 98.

Soap, Toilet, 65.

Soap, Toilet cheaper, 68.

Soap, Toilet, cold made, 72.

Soap, Toilet perfuming and coloring,73.

Soap, Transparent, 82.

Soap, Transparent, cold made, 84.

Soap used for cotton goods, 103.

Soap used in the silk industry, 101.

Soap, Witch hazel, 78.

Soap, Wool thrower's, 100.

Soap, Worsted finishing, 101.

Soda ash, 28.

Sodium carbonate, 28.

Sodium perborate, Use of in soappowders, 57.

Soft soaps, 40.

Soluble mineral matter detm. of in fatsand oils, 173.


Solvay process, 28.

Soya bean oil, 14.

Spent lye, Recovery of glycerine from,106.

Spent lyes, 37.

Spent lyes, Treatment of for glycerinerecovery, 107.

Splitting fats with ferments, 121.

Standard methods of analysis for fatsand oils, 165-196.

Starch and gelatine, Determination insoap, 143.

Stearic acid, 15, 19.

Stearin, 2, 19.

Strengthening change, 36.

Strengthening lyes, 38.

Strunz crutcher, 63.

Sugar in soap, Determination of, 150.

Sugar, Use in transparent soap, 83.

Sulfate of alumina, Use of in spentlyes, 108.

Sulphonated oils, 104.

Sulphur soaps, 77.

Sweating of soap, 62.

Sweet water, 119.

Sylvic acid, 22.

T

Talgol, 96.

Tallow, 4.

Tallow, Fullers' earth bleaching of, 4.

Tallow, Improving color by extractionof free fatty acid, 6.

Tannin soap, 78.

Tar soap, 77.

Test for color of soap, 133.

Testing of alkalis used in soap making,134.

Textile soaps, 98.

Titer, 130.

Tank cars, Sampling, 166.

Tierces, Sampling, 168.

Titer, Standard method, 175.

Titer, Note on, 189.

Tung oil, Note one iodine, number of,180.

Toilet soap, 65.

Toilet soaps, Cheaper, 68.

Toilet soap, Use of hardened oils in,96.

Total alkali, Determination of in soap,147.

Total fatty and resin acids,Determination of in soap, 144.

Train oils, 20.

Transparent soap, 82.

Transparent soap, Cold made, 84.

Troweling soap, 52.

Tsujimoto, ref., 20.

Tubes for transparent soap, 85.

Turkey red oil, 104.

Twaddle scale, 25.

Twitchell method for rosin, 145.

Twitchell process, 113.

Twitchell process, Advantages, 113.

U

Unsaponifiable matter, Determinationof in oils and fats, 132.

Unsaponifiable matter, Determinationof in soap, 148.

Unsaponifiable matter, determinationof by standard method, 176.

V

Vacuum Oven, Standard, 176.

Vegetable oils, 6.

W

Water, 29.

Water, Hard, 29.

Witch hazel soap, 78.

Wool thrower's soap, 100.

Worsted finishing soaps, 101.

Z

Zinc oxide, Use of in autoclavesaponification, 120.

Zinc oxide, Use of in soap, 33.

LITERATURE OFTHE CHEMICAL

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The Soap-Maker's BookShelf

A list of standard books relating tosoapmaking and allied industries.

Published and For Sale byD. VAN NOSTRAND COMPANY

Publishers and Booksellers8 WARREN STREET NEW

YORK

Askinson, George W. Perfumes andCosmetics. Their preparation andmanufacture. Fourth Edition, translatedfrom the German, and revised with

additions by W. L. Dudley. 32illustrations. 6-1/4 × 9-1/2. Cloth. 354pp. New York, 1915. $5.00

Chalmers, T. W. The Production andTreatment of Vegetable Oils. Includingchapters on the refining of oils, thehydrogenation of oils, the generation ofhydrogen, soap making, the recoveryand refining of glycerine, and thesplitting of oils. 95 illustrations, 9folding plates. 8 × 11-1/2. Cloth. 163pp. London, 1919. $7.50

Deite, C. Manual of Toilet Soap-Making. Comprising toilet soaps,medicated soaps, and other specialties.Second Revised Edition. 85illustrations. 6-1/2 × 10. Cloth. 356 pp.

London, 1920. $7.50

Ellis, Carleton G. The Hydrogenationof Oils, Catalyzers and Catalysis andthe Generation of Hydrogen andOxygen. Second Edition, thoroughlyrevised and enlarged. 240 illustrations.6-1/4 × 9-1/2. Cloth. 767 pp. N. Y.,1919. $7.50

Fischer, M. H. Soaps and Proteins,Their Colloid Chemistry in Theory andPractice. With the collaboration of G.D. McLaughlin and M. O. Hooker. 114illustrations. 6 × 9-1/4. Cloth. 281 pp.New York, 1921. $4.00

Holde, D. The Examination ofHydrocarbon Oils, and of the

Saponifiable Fats and Waxes.Translated from the Fourth GermanEdition by Edward Mueller. 115illustrations. 6-1/4 × 9-1/4. Cloth. 499pp. N. Y., 1915. Net, $5.00

Hurst, G. H. Soaps. A practicalmanual of the manufacture ofdomestic, toilet and other soaps.Second Edition. 66 illustrations. 6 × 8-3/4. Cloth. 385 pp. London, 1907. $6.00

Hurst, George H., and Simmons, W.H. Textile Soaps and Oils. A handbookon the preparation, properties, andanalysis of the soaps and oils and intextile manufacturing, dyeing andprinting. Third Edition, revised. 12illustrations. 5-1/2 × 8-3/4. Cloth. 212

pp. London, 1921. $4.00

Koller, T. Cosmetics. A handbook ofthe manufacture, employment, andtesting of all cosmetic materials andcosmetic specialties, with numerousrecipes. Translated from the German.Third Edition. 5 × 7-1/2. Cloth. 264 pp.London, 1920. $3.50

Koppe, S. W. Glycerine. Itsintroduction, Uses and Examination.For chemists, perfumers, soapmakers,pharmacists, and explosivestechnologists. 7 illustrations. 5-1/4 × 7-1/2. Cloth. 260 pp. New York, 1915.$3.50

Lamborn, L. L. Modern Soaps,

Candles, and Glycerin. A practicalmanual of modern methods ofutilization of fats and oils in themanufacture of soaps and candles, andthe recovery of glycerin. 228illustrations. 6-1/2 × 9-1/4. Cloth. 708pp. N. Y., 1906. $10.00

Murray, B. L. Standards and Tests forReagent Chemicals. 6 × 9. Cloth. 400pp. New York, 1920. $3.00

Parry, Ernest J. The Chemistry ofEssential Oils and Artificial Perfumes.Vol. I, Monographs on Essential Oils.Fourth Edition, revised and enlarged.51 illustrations. 6-1/4 × 10. Cloth. 557pp. London, 1921. $9.00

Vol. II. Constituents of Essential Oils,Synthetic Perfumes and IsolatedAromatics, and the Analysis ofEssential Oils. Third Edition, revisedand enlarged. Illustrated. 351 pp.London, 1919. $7.00

Partington, J. R. The Alkali Industry.63 illustrations. 5-1/2 × 8-1/2. Cloth.318 pp. London, 1918. $3.00

Rogers, Allen. Industrial Chemistry. Amanual for the student andmanufacturer. Third Edition,thoroughly revised and enlarged. 377illustrations. 6-1/2 × 9-3/4. Flexiblefabrikoid. 1255 pp. New York, 1920.$7.50

Scott, Wilfred W. (Editor). StandardMethods of Chemical Analysis. Amanual of analytical methods andgeneral reference for the analyticalchemist and for the advanced student.Second Edition, revised, withadditional tables. 142 illustrations, 3color plates. 7 × 9-1/4. Cloth. 900 pp.N. Y., 1917. $7.50

Simmons, W. H. Fats, Waxes andEssential Oils. In Press.

Simmons, William H. Soap. Itscomposition, manufacture andproperties. 11 illustrations. 4-3/4 × 7-1/4. Cloth. 133 pp. London, 1916. $1.00

Simmons, W. H., and Appleton, H. A.

The Handbook of Soap Manufacture.27 illustrations. 6 × 9. Cloth. 166 pp.London, 1908. $4.00

Van Nostrand's Chemical Annual.Edited by John C. Olsen. A handbookof useful data for analyticalmanufacturing and investigatingchemists and chemical students. FourthIssue, enlarged. 5 × 7-1/2. Flexiblefabrikoid. 785 pp. New York, 1918.$3.00

Watt, A. Art of Soapmaking. Apractical handbook of the manufactureof hard and soft soaps, toilet soaps, etc.Seventh Edition, revised and enlarged.43 illustrations. 5-1/4 × 7-1/2. Cloth.323 pp. London, 1918. $4.00

Wright, C. R. A. Animal andVegetable Fixed Oils, Fats, Butters,and Waxes: Their Preparation andProperties, and the ManufactureTherefrom of Candles, Soaps, andOther Products. Third Edition, revisedand greatly enlarged by C. AinsworthMitchell. 185 illustrations, 3 plates. 6 ×9. Cloth. 953 pp. London, 1921. $16.50

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