DAVID E. GUSHEE, Associate Editor, in collaboration with

OSCAR L. SCHERR, Process Chemicals Co., Santa Fe Springs, Calif. I Specialty Surfactants

Process Chemicals Co.’s formula for success in manufacturing specialty surfactants:

d Technical competence

d Solving customer problems with specially tailored chemicals

d Equipment which allows flexible operation

Pmvious articles in I&EC’s series of Staff-Industry Collaborative Reports have described the manufacture of metal- lic soaps (4) , fatty acid amides (3) , specialty soaps (8) , synthetic detergents from petroleum in France (2), and syn- thetic detergents by Procter & Gamble’s continuous process (7).

This article supplements those, de- scribing the manufacture of specialty surface active agents of a variety of types and a variety of properties, as carried out by Process Chemicals Co. of Santa Fe Springs, Calif.

Process Chemicals makes surfactants falling into all three basic categories- anionic, nonionic, and cationic. In all, it produces six major types of surfactants, although the lauryl sulfates make up about one third of the company’s pro- duction.

Lauryl sulfates (anionic) Fatty alkanol amide condensates (non-

Glycerol fatty acid esters (nonionic) 0 Polyethylene glycol fatty acid esters

Polyethylene glycol fatty alcohol poly-

ionic)

(nonionic)

ethers (nonionic) and amine polyethers (cationic) Quaternary ammonium compounds (cationic) This article gives a typical example of

each of these types of surfactants, de- scribes its uses, and points out some modifications which the company uses to make products similar but with properties changed slightly in one way or another.

Process Chemical’s forte is solving specific customer problems with specific chemicals tailored to those problems -even though it may not have that exact chemical in its line. Once the chemical has been added to the line, the company then tries to find other sales outlets for it.

It was formed in 1947 and made as its first product sodium sulfide, a chemical then in short supply as a result of wartime exigencies. When other companies en- tered this market a year or so later, Process Chemicals discontinued its pro- duction and switched to the surfactant field. The first surfactant made by the company was a polyethylene glycol stearate for use in ice cream and bread.

From 1947 to 1955, the company was housed in an old wooden building in the heart of a residential area in Los Angeles. During this period the number of prod- ucts continually grew. The alkanol amides, lauryl sulfates, and polyethylene glycol esters for industrial emulsifiers were added to the line. By 1955, annual sales had grown to $350,000 and monthly production to 100,000 pounds. So as to expand further, the company moved to its present location-a five-acre tract in Santa Fe Springs which the company had purchased in 1951 in anticipation of this need.

Since this move, Process Chemicals has grown rapidly to where, in 1958.

Reactors 5 and 4 as seen from catwalk gives access to their tops. at reactor 2

Operator i s

798 INDUSTRIAL AND ENGINEERING CHEMISTRY

Reactor 5 i s at right and a mixing tank is at left. Note: Opera- tors move so fast in this plant that they blur

From the catwalk this picture shows the row of proc- ess vessels on the other side. Two Pfaudler reactors are at left center; the large reactor at right center is vessel 8, the neutralizer

it had gross surfactant sales of $1,500,000 and a production rate of some 500,000 pounds per month. I t has about 350 products on its list and is constantly adding more. I t is now one of the primary West Coast producers of sur- face active agents and has one of the most complete lines of surfactants on the West Coast.

Most of its customers are also in the West. However, it has developed some products for West Coast branches of Eastern companies and ships some of these products to the Eastern plants of these companies. Market areas for other company products are also broad- ening, as sales effort expands.

Equipment

In making its specialty surfactants, Process Chemicals uses for the most part simple reactors, pumps, and tanks.

There are two main processing areas: the ethylene oxide plant, where re- actions using ethylene oxide and propyl- ene oxide are handled; and the general process area, where all the other reac- tions are carried out.

At first glance, the general process area looks like a large semiworks. The reason for this appearance is clear. When a company makes as many differ- ent products as Process Chemicals does, it makes relatively small amounts of each one. Thus, it needs many vessels, each as versatile as possible, in order to simplify scheduling of production runs.

The general process area has four stainless steel reactors of varying sizes and two glass-lined Pfaudler reactors, plus five stainless steel tanks for mixing, neutralizing, heating, cooling, or holding batches of materials. The glass-lined reactors are used mostly for reactions requiring chlorosulfonic acid. Stainless steel is used elsewhere, so that choice of reactor need not be limited by materials of construction.

Instrumentation is held to the absolute minimum consistent with maintaining

product quality. All reactors have metering of liquids, and reaction condi- temperature and pressure indicators, tions by hand. while three have automatic temperature Because many of the product tend to controllers. Operators control flow rates, foam, aerate, or absorb moisture when

Typical Operating Instructions

How Process Chemicals Makes lauryl Sulfates

PCC makes a variety of lauryl sulfates of different fluidity, foam proper- ties, and detergency. These various lauryl sulfates have been developed over the years in response to requests for specific properties that customers have wanted in their shampoos. These properties are controlled by the content of sodium chloride, sodium sulfate, and free fatty acid, plus the composition of the lauryl alcohol fraction used (commercial lauryl alcohols vary from 60% to 95% Clz content).

Detergency is more dependent on content of longer-chained fatty alcohols. Solid paste shampoos require high salt contents and are buffered to pH 9.0 to 9.5 with sodium bicarbonate or borax. Liquid shampoos are buffered to a lower pH (7.5 to 8.0) with sodium citrate or the like.

Batch size depends on the particular lauryl alcohol used for a given product and is adjusted to use one complete drum of chlorosulfonic acid per batch. The company does not want any ClSOsH left around in partly-full drums.

In a shampoo, volume of foam depends on the Clz content.

The plant procedure is about like this:

,Charge the lauryl alcohol to a glass-lined reactor. Pull slight vacuum on the reactor through an absorption system, to remove by-product HCI as it i s formed and to neutralize it.

Feed rate is about 4 Ib. per min. and is controlled manually by a needle valve; the full drum is charged in about 3 hours. Reaction temperature is held at 75' to 90" F. by cooling water in the reactor jacket.

When the reaction is complete, pull a high vacuum on the reactor and blow the reaction mixture with COS to strip out all remaining HCI. Then pressurize the reactor with COz. , During the reaction period, prepare a caustic solution in the neutralizing tank, using enough caustic and enough water to bring final pH and con- centration to the desired levels. , Blow the reaction mixture from the glass-lined reactor into the caustic solution with COz pressure. , Check batch in laboratory for sulfite content. Add sodium hypochlorite as required to oxidize sulfite to sulfate. This treatment also bleaches the product.

,Formulate to final pH and viscosify by adding salts, excess free fatty

,Charge chlorosulfonic acid from the drum, using COz pressure.

Agitate and cool to 45" F.

Agitate to ensure homogeneity.

buffering agents. e after laboratory appr

VOL. 51, NO. 7 ~ JULY 1959 799

MIXER 12 @ - I TO DRUMS

TO VENTILATING

SCRUBBER SYSTEM - FAN,THROUGH

CONDENSER = REACTOR T I I

NITROGEN-TO - To e- EACH REACTOR

F FROM 4 TO DRUMS

DRUMS FROM

TO D ~ U M S

DRUMS DRUMS

CARBON DIOXIDE- TO EACH REACTOR e-

REACTOR 2

REACTOR I Q J 1

TO DRUMS TO DRUMS

GENERAL PROCESS AREA-NORTH SIDE

TO NEUTRALIZER EJECTOR

CARBON DIOXIDE

71 r MIXER

ti- TO DRUMS 2 FROM 5 DRUMS

GENERAL PROCESS AREA-SOUTH SIDE

I/EC PLANT PROCESS SERIES

MIXER

TO DRUMS TO DRUMS

Flowsheet for the manufacture of specialty surfactants, Process Chemicals Co., Sante Fe Springs, Calif.

800 INDUSTRIAL AND ENGINEERING CHEMISTRY

SPECIALTY SUR FA CTANTS

pumped, they are transferred from one vessel to another with compressed nitro- gen or carbon dioxide whenever possible. T o minimize permanent piping, and to keep the plant as versatile as possible, pumps are mounted on portable stands and hooked up with flexible tubing when needed.

Often all six reactors are in use at one time. So that only two operators can handle all these reactions, the reactors and auxiliary vessels are installed in two rows about 20 feet apart. Despite the heterogeneity of the operations, however, these two men can adequately handle all of these at once. The physical operations are relatively simple even though the chemistry involved is often complex.

The ethylene oxide plant, on the other hand, is more extensively instrumented and has more safety features. The whole area is separated from the general process area by a fence, and is run by one operator, closely supervised by a chemical engineer. Reactions are car- ried out in a 500-gallon, stainless steel pressure reactor. There are two 500- gallon, pressure, scale tanks, one for ethylene oxide, and one for propylene oxide, from which these reactants are weighed into the reactor. These are backed up by two 10,000-gallon under- ground storage tanks-again, one each for ethylene oxide and propylene oxide.

In this area, all electrical equipment is class I, group D; there is a manually- operated _sprinkler system, an automatic alarm signaling any overly-rapid pres-

Reactor 7, showing some of the auxiliary equipment, with neutralizer 8 open at right

sure increase, and a large emergency vent line, with two pop-off valves and a rupture disk in it, running straight up through the roof from the reactor. Temperature and pressure are pneumat- ically controlled and are recorded on a central instrument panel. Temperature and pressure controllers are interlocked with the oxide feeding system; when one or the other exceeds a preset figure, feed values are closed automatically.

Before oxide is transferred into any

vessel in this unit, it is always purged with dry nitrogen until a Hays gas analyzer shows it to be free of oxygen. Purging eliminates the danger that explosive mixtures might form. All equipment is thoroughly grounded and interconnected so that no static elec- tricity can be created. Oxide in the storage tanks is kept under a constant nitrogen pressure of 50 p.s.i. and the oxide is transferred from one vessel to another by nitrogen pressure.

Equipment Ref.

@E)

Function Reactor

Neutralizer

Mixer

Tank, storage Tank, feed, CHZCHZO Reactor, CHZCHZO Ribbon blender Grinder Drum flaker Pump, gear

Pump, centrifugal Filter, plate and frame Filter, leaf Ejector, 3-stage

Flow- sheet Ref.

1 2

3 4

5 6 7 8

9 10 11 12 13 14 15

Major Processing Equipment

Capacity 10 gal.

300

600 1,500

3,000 100 350 700

50 600 500 500

10,000 500 500

1000 Ib./batch ... ... 50 gal./min.

30 12 15

Size 12 310 sq. in. 10 in., to 10

mm. Hg

Matl. of Const. Type 316, S.S.

Glass-lined

Type 316, 8.8.

. I .

Type 316, 8.9. ... ... ... ... ... ... Type 316, 8.8.

Type 316, s.6. ... ...

Temp. Control Steam jacket Gas-fired and

steam coil

Steam coil and gas-flred

Steam coil Jacket

Steam coil

Jacket

Steam coil

... ... Jacket ... ... ... ... ...

e . . ... ... ... ...

Working, P.S.I.

15 50

so Atm.

25 75

Atm.

125 290 200 ... ... ... ... I . . ... ... ... ... ...

Agitation Kind HP.

Blade 1 2

3 Side-entering 3

Blade 10 Anchor 2

5 Variable speed 5

Blade 1 blade

Side-entering 1 Propeller 1 ... ... ... Blade' * . 7 '/z ... 15 ... 3 ... IVZ ... ... ... . a . ... ... ... ... ... ... ... ... ... ...

VOL. 51, NO. 7 JULY 1959 801

General view of the ethylene oxide plant, covered with tarpaulin to keep out the cool, wet winter weather. Maze of pipes inside the corrugated metal housing is a pilot plant; instrument panel rear to the right of pilot plant i s nerve- center of the ethylene oxide plant

Under this assemblage of pipes, valves, and vent lines are the two underground storage tanks for ethylene oxide and propylene oxide. Each holds 10,000 gallons and i s kept under nitrogen pressure at all times. Contents are fed from here to scale tanks inside to the right when needed for a batch

CHB 0 I I1

Analytical Control

HO-CH-CX-NH~ + H O - C - C ~ ~ H ~ ~ - All raw materials are checked against specifications before they are released for use in the plant. Tests include melt-

L A I

indices, and infrared spectra, among others.

Products are tested for such proper-

such as foaming tendency, ability to emulsify standard materials, or the like. The control laboratory in which these

tests are run is just off the general process area to keep to a minimum the time between sampling and approval for packaging.

The analytical and research labora- tories are compact and well equipped. The staff includes four research men, two control chemists, and two laboratory technicians. Equipment includes a Per- kin-Elmer Infracord infrared spectro- photometer, Bausch & Lomb refractom- eter and Spectronic 20, Brookfield viscometer, Du Nouy tensiometer, Laun- der-Ometer and reflectometer, micro- scope, centrifuge, two Beckman pH meters. and the usual laboratory glass- ware.

Inventory Control

With the tremendous number of raw materials, intermediates, and final prod- ucts which must be kept on hand, Process Chemicals has an inventory problem. Making things even worse is the advantage of buying raw materials in bulk yet the disadvantage of a relatively low production rate. The company has not yet found a truly satisfactory solution to the dilemma. I t therefore has extensive storage facilities, tankage, and inventory records, and tries to keep a balance among all these competing factors.

The company has developed a system of inventory entry and withdrawal slips Ivhich requires clearance through the inventory clerk. This a t least keeps the records up to date. As for purchas- ing liquids in bulk, the company does so when it can get a good price, then it repackages from the tank car or truck into drums for storage at the plant. Its more common liquid reagents, such as tall oil, coconut oil, and the like, have their own permanent storage tanks.

The Manufacture

Patty Alkanol Amide Condensates. These are usually foam stabilizers, thick- eners, and, when used with lauryl sul- fates or other anionic surfactants, deter- gency improvers. A typical example produced by Process Chemicals is lauric isopropanol amide. I t is made by heating lauric acid with monoisopro- panolamine (G).

PCC makes other amide condensates by a similar process. For water-soluble liquids, it uses coconut fatty acid, coconut oil, or methyl laurate as the hydrophobic constituent and diethanol- amine as the hydrophilic part. By

802 INDUSTRIAL AND ENGINEERING CHEMISTRY

SPECIALTY SURFACTANTS

1 1 I I EMERGENCY

OXIDE

TANK 14

I I-

FROM RA I LROAD NITROGEN

TANK CARS PRESSURE

ETHYLENE OXIDE STORAGE TANK 13

I VENT TO ROOF

RUPTURE DISK

, FATTY ACID, I -

PROPYLENE OXIDE

TANK 14

4- PROPYLENE

OXIDE

TANK 14

p--7 I I

FROM RAILROAD NITROGEN

TANK CARS PRESSURE

PROPYLENE OXIDE STORAGE TANK 13

REACTOR 15 WATER IN ,

*WATER OUT

FINISHED PRODUCT

PRESSURE, HIGH -LEVEL

- -- - -- - - - --- - -._

TEMPERATURE To HIGH-LEVEL SHUT -OFF

EJECTOR

TO SUMP

a CHECK VALVE

Flowsheet for the manufacture of polyethylene glycol fatty acid and amine or alcohol polyethers

changing the hydrophobic part to oleic acid or castor oil and using again di- ethanolamine as the hydrophilic part, the company obtains products which are oil-soluble.

Lauryl Sulfates. Largest volume market for lauryl sulfates lies in shampoos. They can be made as pastes or as clear liquids by varying the ingredients during preparation. A typical example of a simple paste is sodium lauryl sulfate. This is made by reacting lauryl alcohol

Inside the reaction building, there i s one tank each for ethylene oxide and for propylene oxide. They are mounted on scales so that operator can follow rate of weight change. VaIv- ing is arranged so that the under- ground storage tank is never con- nected directly to the reactor through the scale tank. Check valves prevent contents from flowing back through the system. Here, valve setting is checked on t h e ethylene oxide scale tank

(usually not a pure compound but a mixture of straight-chain alcohols, as a pure alcohol costs too much for most uses) with chlorosulfonic acid and neutralizing the lauryl sulfuric acid with caustic soda. Hydrochloric acid gas is continuously removed by vacuum as it is formed, so that per cent of sodium chloride can be held to a minimum.

25' C. ClzHz60H + ClSOaH -+

NaOH HCI + CizHzsOSOaH -+

ClzHz~OS03Na + HzO + NaCl

The sodium lauryl sulfates are supplied usually as 30% active pastes, with the consistency controlled by the content of sodium chloride, sodium sulfate, and free lauryl alcohol to the customers' requirements.

To make a liquid rather than a paste, Process Chemicals uses some base other than caustic-for example, ammonia, diethanolamine, or triethanolamine-to neutralize the lauryl sulfuric acid.

neutralizing lauryl sulfuric acid with a product of the first category above-a fatty alkanol amide condensate such as diethanolamine condensed with cocoa- nut fatty acid (2 moles of amine to 1 mole of fatty acid) (5 ) .

Using these in place of the sodium en- hances foaming, wetting, and detergent action in some applications, depending on what the formulator adds to them in his proprietary mixture.

Process Chemicals makes modified products of this general nature by

Flaker i s used to chill and flake high melting finished products

VOL. 51, NO. 7 JULY 1959 803

Such products are 10070 active liquids, are anionic-nonionic blends, and are used in compounding liquid dishwash- ing products, bubble baths, and sham- poos.

Glycerol Fatty Acid Esters. These products are used as emulsifiers by the food industry. They are mixtures of monoglycerides, diglycerides, and tri- glycerides, with the proportions of each controlled by the ratio of reactants and the reaction conditions. They are made by reacting glycerol with a fattv acid.

CHqOH 0 il 230’ C. + HOC-C17H36-+

CkzOH

0

d H + H O I

CHzOH

In order of increasing hydrophobicity are esters of palmitic, stearic, and oleic acids. With a given fatty acid, the higher the content of monoglyceride. the more hydrophilic is the product.

Using a 1:l mole ratio of reactants; Process Chemicals gets a product con- taining about 45% monoglyceride, 50% diglyceride, and 5% triglyceride. The company also can get products with higher mono contents (and correspond- ingly higher hydrophilicity) by using higher ratios of glycerol and higher reaction temperatures.

Polyethvlene Glycol Fatty Acid Esters. This type of nonionic surface active agent is made in the ethylene oxide plant by reacting ethylene oxide with a fatty acid, and controlling the amount of ethylene oxide added so that it polymerizes to the desired chain length. Dilute sodium hydroxide is the catalyst. The products are widely used as wetting agents, emulsifiers, and cmol- lients.

0 II NaOH

CI7H~p~,s~,C-OH f n CHZ-CHZ ---+ 165” C.

‘ ? - (tall oil fatty acids)

sible to tailor-make one of these prod- ucts to almost any balance of hydro- phobic-hydrophilic properties desired.

Polyether Condensates. These prod- ucts are much like the preceding group except that they are ethers, not esters, and they are much more stable to acids, alkalies, and hydrolysis. Because of this great stability, these products are used where their inertness is needed, such as in insecticide emulsifiers and heavy duty detergents, both acid and alkaline.

They are made by the same process 0

This compound is made in two steps. First, stearic acid is reacted with dimethylaminopropyl amine. Benzyl chloride is then added, isopropyl alcohol and then soft water are also added and finally the concentration is ad- justed to 30% active.

Process Chemicals also makes a series of disubstituted imidazoline quaternaries, using oleic acid or tall oil fatty acids. Quaternaries of this type are oil-soluble and have both anticorrosion and bacte- ricidal properties.

I

II H H H H 245’ C. C~~HSSC-OH + HN-C--C--N-C~HIOH --+

H H N--CHg II I

C,,H,,---C dH, + 2 H20 -4

\/ N-CZHdOH C-J\)-CH,Cl

as the ester previously described, except that alcohols or amines are used in place of the acids used in the other case.

NaOH

\/ 165” C. C ~ H ~ , ~ O H + 72 CH~-CH~ --+

0

c , H ~ ~ ~ - o ( c H , - c H ? - ~ ) , - CH~--CH~OH

For some uses. mixtures of ethoxy and propoxy units are superior to either alone. The propoxy chains tend to keep the products liquid and also to reduce foaming.

Cationics. The outstanding charac- teristic of these compounds is the positive charge carried by the large organic am- monium ion. This property is responsi- ble for the neutralizing effect the cat- ionics have on anionic detergent resi- dues-used in textile sofxeners and cream rinses for the hair. The positively charged organic ion is also attracted to metals, paving aggregates, and other negatively charged surfaces, leading to uses such as corrosion inhibitors and asphalt antistripping agents. In ad- dition, some of these quaternary am- monium compounds have bactericidal activity.

0 / I

C ~ ~ H ~ ~ ~ , ~ ~ , C - O ( C H Z - C H ~ - ~ ) ~ - I CHzCHzOH

In a homologous series of these chem- icals, hydrophilic properties increase as the polyoxyethylene chain length in- Process Chemicals makes a stearyl creases and as the fatty acid chain quaternary ammonium compound which length decreases. It is therefore pos- is typical of these materials.

0

r o l+

References

(1) Fedor, W. S., Strain, B., Theoharous, L., White, D. D., IND. ENG. CHEM. 51, 13 (1959).

(2) Inskeep, G. C., Mussard, A., Zbid., 47. 2 11955).

(3) k 162(

(4) K

(5) Katzm 41, i w o w

1952). (6) Ibid., 2,757,143 (July 31, 1956). (7) Price, C. C., “Surface Active Agents”

in “Encyclopedia of Chemical Technol- ogy,” Kirk, R. E., Othmer, D. F., eds., Vol. 13, p. 252, Interscience, New York, 1954.

(8) Reese, K. M., Trusler, R. B., Bugas, I. T., IND. ENC. CHEM. 46,1354 (1954).

Processing Equipment

(1E) Alsop Engineering & Mfg. Corp.,

(2E) Bayview Welding Works, Wilmington,

(3E) Doering, C., & Sons, Inc., Chicago,

Milldale, Conn., leaf filter.

Calif., reactors, mixers.

Ill., drum flaker, Model M. (4E) .Elliott Co., Jeannette, Pa., ejector,

IO-inch, 3-stage to 10-mm. mercury. (5E). Fitzpatrick, W. J., Co., Chicago, Ill.,

grinder, ModelD. (6E) Lewis, P. B., Machine Co., Los

Angeles, Calif., ribbon blender. (7E) Master Electric Co., The, Dayton,

Ohio, centrifugal pump. (8E) National T a n k & Mfg. Co., Los

Angeles, Calif., feed and storage tanks. (9E) Pfaudler Co., Rochester, N. Y., re-

actors. (10E) Shriver, T., & Co., Inc., Harrison,

N. J., plate and frame filter press, size 12, 16 plate.

(11E) Viking Pump Co., Los Angeles, Calif., gear pumps.

804 INDUSTRIAL AND ENGINEERING CHEMISTRY