Detailed Revision Alcohol phenol and ethers Introduction of hydroxy compounds.Hydroxy compounds are compounds in which the hydroxy group, OH is directly linked with the aliphatic or aromatic carbon. Hydroxy compounds can be classified into following three categories. (1)Aliphatichydroxycompounds(alcohols):Alcoholsareregardedashydroxyderivativesof hydrocarbons. Alcohol n HydrocarboOH R H ROHH (R = alkyl group) Theycanbemono,diortri-hydricalcoholsdependinguponwhethertheycontainone,twoorthree hydroxy groups. Monohydric alcohols Dihydric alcoholTrihydric alcoholPolyhydric alcohol Methanol3OH CHGlycol22|OH CHOH CH Glycerol22||OH CHOH CHCHOHMannitol orsorbital 22||4) (OH CHOH CHCHOHEthanol5 2OH H C(2) Aromatichydroxy compounds(Phenols): Phenols are regarded as hydroxy derivatives of aromatic hydrocarbons (arenes). Phenol AreneOH Ar H ArOHH

Theycanbemono,diortri-hydricphenolsdependinguponwhethertheycontainone,twoorthree hydroxy groups. Monohydric phenols : Dihydric phenols : OH OH Catechol OH Resorcinol OH Quinol OH OH OH Phenol CH3 o-cresol OH CH3 m-cresol OH p-cresol CH3 OH OH OH Pyrogallol OH OH OH OH OH Phloroglucinol HO OH Trihydric phenols : (3)Aromaticalcohols:Compounds in which the hydroxy group is present in the side chain are termed aromatic alcohols.

Monohydric alcohols.Alcoholscontainingonehydroxylgroupareknownasmonohydricalcohols.Thesealcoholsmaybe saturated or unsaturated depending on the nature of hydrocarbon groups. Saturated monohydric alcohols form ahomologousseriesofthegeneralformulaOH H Cn n 1 2.TheyarealsorepresentedasROHwhereR represents an alkyl group. They may be regarded as derivatives of water,i.e., one hydrogen atom of the water molecule is replaced by an alkyl group. Alcohol WaterOH R HOHRH (1) Classification : Monohydric alcohols are subdivided into three classes (i) Primary alcohols : In these alcohols, the hydroxyl group is attached with primary) 1 (o carbon atom. They possess a characteristic groupOH CH2 and their general formula isOH RCH2. R may be H in the first member and alkyl group in the rest of the members. Examples : alcohol Methyl 2OH HCH ; alcohol Ethyl 2 3OH CH CH ; alcohol propyl-2 2 3nOH CH CH CH ; alcohol isobutyl 233OH CH CHCHCH (ii) Secondary alcohols : In these monohydric alcohols, the hydroxyl group is attached with secondary (2) carbon atom. They possess a characteristic group CHOHand the general formulaCHOHRR (R and Rmay be same or different). Example : alcohol Isopropyl 33CHOHOH CH OH CH; alcohol butylsec.35 2CHOHCHH C (iii) Tertiary alcohols : In these monohydric alcohols, the hydroxyl group is attached with tertiary (3) carbon atom. They contain a characteristic group COH and have the general formulaOHRRR (R, Rand Rmay be same or different). CH2OH Benzyl alcohol CH2CH2OH 2 phenyl ethanol Examples : alcohol Butyltert.33||3CHCHOH C CH ; alcohol Amyltert.33||5 2CHCHOH C H C(2) Nomenclature (i) Common system :Named as alkyl alcohol. Note:Inhighermembers,itisalwaysindicatedwhethertheOHgroupisattachedtoprimary, secondary and tertiary carbon. By prefixing n for primary sec. for secondary and tert. for tertiary. Example : alcohol Ethyl 2 3OH CH CH ; alcohol butylsec.3|2 3CHOHCH CH CH ;alcohol butyltert.33||3CHCH OH C CH(ii) Carbinol system :OH CH3 is called carbinol. All other members are considered its alkyl derivatives. Example : Carbinol3OH CH ; carbinol methylDi33CHOHCHCH; carbinol Isopropyl 233OH CHCHCHCH (iii) IUPAC system : Named as alkanol. Example : Methanol3OH CH ; 1 - Propanol2 2 3OH CH CH CH ; 1 - Butanol2 2 2 3OH CH CH CH CH(3) Structure : Oxygen of OH group is bonded to 3sphybrid carbon by a sigma bond. (4) Isomerism (i) Chain isomerism : 1 - panol Methyl pro 223|31 - Butanol2 2 2 3OH CHCHCH CH OH CH CH CH CH(ii) Positional isomerism : 2 - Propanol3|31 - Propanol2 2 3CHOHCH CH OH CH CH CH(iii) Functional isomerism : methane Methoxy3 3Ethanol2 3OCH CH OH CH CH(5) General methods of preparation of monohydric alcohols C OHHHH bondsp3 sp3 C OC O H = 108.5C O bond length = 142 pm HHHH HO | H CH | H 108.5 . . : (i) From alkyl halide :KBr OH H C KOH Br H CEthanol5 2(Aqueous)e Bromoethan5 2;AgBr OH H C AgOH Br H CEthanol5 2oxide silverMoist e Bromoethan5 2 Note : 1 alkyl halide gives good yield of alcohols. 2 alkyl halide gives mixture of alcohol and alkene. 3 alkyl halide gives alkenes due to dehydrohalogenation. O H KBrCHCH C CH KOHCHBr CH C CH2duct) (Major proene Methylprop - 232|3(Aqueous)33||3 Oxidation number of carbon in different organic compounds are given below in increasing order, order increasing in carbon ofnumberOxidations derivative acid and acids compounds, carbonylalcohol, halide, alkylalkyne, alkene, Alkane, Alkanesandalkenescanbeconvertedintoalcoholsbyoxidationmethodwhilecarbonyl compounds, acid and their derivatives can be converted into alcohol by reduction. Oxidation no. of carbon in RX and ROH is same hence RX converts into ROH by displacement reaction. (ii) From alkenes (a) Hydration Direct process : Alcohol|||| AlkeneH OH C C C CHOH Indirect process : 4 2Ethanol2 3Boilsulphate hydrogen Ethyl 2 2 3acid Sulphuric 2Ethene2 22SO H OH CH CH OH OSO CH CH OH HOSO CH CHO H In case of unsymmetrical alkenes ol 2- - Propan3|3Boil23|3rules ' ff' Markowniko2Propene2 32CHOHCH CHOH OSOCH CH CH OH HOSO CH CH CHO H (b) Oxymercuration-demercuration O HCHCH C233| 4 232|SO HCHH CH CAlcohol33||CHOHCH CAlcohol| |ion Demercurat||||tion Oxymercuraacetate Mercuric 2 24) (H OHC CHgOAc OHC C OAc Hg O H C CNaBH This reaction is very fast and produces the alcohol in high yield. The alcohol obtained corresponds to Markownikoffs addition of water to alkene. (c) Hydroboration oxidation (HBO) : (Antimarkownikoffs orientation)Alcohol||||,||||2 2OH H C CBCHC B H C COH O H Diborane is an electron defficient molecule. It acts as an electrophile reacting with alkenes to form alkyl boranesB R3. orane Trialkyl b3 2 2rane Dialkyl bo2 2 2ne Alkyl bora22| |2 2) ( ) (2 2 2B CH RCH BH CH CH RH B H CHCH R BH H CH CH RCH RCH CH RCH Other examples : Note : Carbocation are not the intermediate in HBO hence no rearrangement take place. (iii) By reduction of carbonyl compounds : Bouveault Blanc alcohol Primary2 2Aldehyde4OH RCH H RCHOLiAlHPd; alcohol Secondary| / or 2Ketone4ROHCH R H R RCOPt NiNaBH CH = CH2 rule s nikoff' Antimarkow2O H (B2H6) (CH2 CH2)3B CH2 CH2OH 1-Alkanol Hg(OCOCH3)2 rule s ff' MarkownikoH CHCH2 || OCOCH3HgOCOCH3 CH CH3 | OH 2-Alkanol H3O+O H2 CH CH3 CH2 CH3 OH CH2 CH3 Less stable B2H6 CH3 CH3 O H2 CH3 HO H3O+ HO CH2 CH2OH CH2 CH2 CH3 OH 4LiAlHalso reduces epoxides into alcohol :OH CH CH LiAlHOCH CH2 3 4 2 2 Hydride selectively attacks the less alkylated carbon of the epoxide. 33||332|34CHOHCH C CHHCHOCH C CHHLiAlH (iv) By reduction of carboxylic acids and their derivatives alcohol primary2(ii)(i)acid Carboxylic24OH RCH COOH RO HLiAlH; OH R OH RCH R RCOO RCOOHH2Catalyst Ester acid Carboxylic2 Esters are also reduced to alcohols (Bouveault Blanc reaction) Methanol3Ethanol2 3/(Ester) acetate Methyl 3| |35 2] [ 4 OH CH OH CH CH H OCHOC CHOH H C Na Note : Reduction with aluminium isopropoxide is known as Meerwein-Ponndorff verley reduction (MPV) reduction. O CCHCHCHOH Me CHOH CH O C MeOCHMe Al332) (alcohol Isopropyl 2 3 22) ((v) By hydrolysis of ester : Alcohol acid ofsalt Sod.| | | |) aq ( / OH R ONaOC R Na HO R OOC R . (vi) From primary amines :O H N OH CH CH HONO NH CH CHHCl NaNO2 2Ethanol2 3/e Aminoethan2 2 32 Note : It is not a good method of preparation of alcohols because number of by product are formed like alkyl chloride alkenes and ethers. (vii) From Grignard reagent (a) With oxygen :OH X Mg ROH X Mg O R O X Mg RHOHO Al) ( 2 2 2 2223 2 (b) With ethylene oxide OH X Mg OH CH RCH OMgX CH RCHOCH CH X Mg RO H) (2 2 2 2 2 22 Other examplesWith cyclic ester (c) With carbonyl compounds : OH RHC ROMgXRHC RHOC R X Mg RO H|||||| |2 Note : If R= H, product will be 1alcohol. If R= R, product will be 2alcohol. If carbonyl compound is ketone, product will be 3 alcohol. It is the best method for preparation of alcohol because we can prepare every type of alcohols. (viii)Theoxo process:Itisalsocalledcarbonylationorhydroformylationreaction.Amixture of alkene carbon monoxides and hydrogen. Under pressure and elevated temperature in the presence of catalyst forms aldehyde. Catalyst is cobalt carbonyl hydride] ) ( [4CO CoHproduct is a mixture of isomeric straight chain (major) and branched chain (minor) aldehydes. Aldehydes are reduced catalytically to the corresponding alcohols. (6) Physical properties of monohydric alcohols (i)Character:Alcohols areneutral substances. These haveno effect onlitmuspaper.Thisisanalytical test for alcohols. (ii)Physicalstate:Theloweralcohols(uptoC12)arecolourlessalcoholwithcharacteristicsmelland burning taste. The higher members with more than 12-carbon atoms are colourless and odourless solids. (iii)Polarcharacter:OxygenatomoftheOHgroupismoreelectronegativethanbothcarbonand hydrogen. Thus the electron density near oxygen atom is slightly higher. Hydrogen bonding shown below RO HRO HRO HRO H| | | |- - - - - - - - - - - . This gives polar character to OH bond. (iv) Solubility : The lower alcohols are miscible in water. CH3 CH CHO | CH3 CH3 CH CH2OH | CH3 H2 Zn Cu CH3 CH2 CH2 CH2 OH CHO CH CH CH H CO CH CH CH2 2 3 2 2 32 2 2OO + CH3Mg Br OMgBr CH3 O OH CH3 O H2OCH3MgBrH2O HO C CH3 CH3 OH OH CH3 CH3 OMgBr ClBr Mg Br ClCH2OH +Mg O CH2 ClCH2OMg Br Hydrolysis : - - - - - :| |HO HRO H groups alkylofSize1SolubilityIncrease in carbon-chain increases organic part hence solubility in water decreases.Isomeric 1, 2, 3 alcohols have solubility in order 1 > 2 > 3. (v)Boilingpoints:Duetointermolecularhydrogenbondingboilingpointsofalcoholsarehigherthan hydrocarbon and ethers. s of branche No.1B.P. ;B.P. follows the trends : 1 alcohols > 2 > 3 alcohol (vi) Density : Alcohols are lighter than water. Density Molecular masses. (vii)Intoxicatingeffects:Methanalispoisonousandisnotgoodfordrinkingpurposes.Itmaycause blindness and even death. Ethanal is used for drinking purposes. (7)Chemicalproperties:CharacteristicreactionofalcoholarethereactionoftheOHgroup.The reactions of the hydroxyl group consists of either cleavage of C O bond or the cleavage of O H bond. C O bond is weaker in the case of tertiary alcohols due to +I effect of alkyl groups while OH bond is weaker in primary alcohols as electron density increase betweenO H bond and hydrogen tends to separates as a proton. Primary||H OHHC R; SecondaryOH CHRR; TertiaryH O CRRR Thus primary alcohols give the most of reaction by cleavage of O H bond while tertiary alcohols are most reactive because of cleavage of C O bond. Hence O H cleavage reactivity order : Primary > Secondary > Tertiaryand C O cleavage reactivity order : Tertiary > Secondary > Primary alcohol (i) Reaction involving cleavage ofwith removal of H as proton Alcohols are stronger acids than terminal acetylene but are not acidic enough to react with aqueous NaOH or KOH. Acidic nature is in the orderRH NH CH CH ROH HOH3. AcidicnatureofalcoholdecreasewithincreaseofalkylgroupsonOHbondedcarbondueto+I (inductive) effect of alkyl group. H ORRC R H ORHC R H OHHC R||| (a) Reaction with Na : (Active metals) 22 2 2 H ROM M H RO (M = Na, K, Mg, Al, etc.)weaker bond weaker bond H O C|| Polar bond Evolution of 2Hshows the presence of OH and reaction show that alcohols are acidic in nature. Alcohols acts as Bronsted acids because they donate a proton to astrong base) (: B . Example : acid Conjugate base) (conjugateAlkoxideBase(acid)Alcohol:. .. .:. .. .H B O R B H O ROn reaction of alkoxide with water, starting alcohol is obtained. base Conjugate acid ConjugateBase Acid:. .. .. .. .OH H O R O R H O HThis is the analytical test for alcohols. (b) Reaction with carboxylic acid [Esterification] : Alcohol acidR O H OH RCO O H R RCOO2Ester When HCl gas is used as catalyst, the reaction is called fischer-speier esterification. Presenceofbulkygroupinalcoholorinaciddecreasestherateofesterification.Thisisduetosteric hinderence of bulky group. Reactivity of alcohol in this reaction is o o o3 2 1 . (c) Reaction with acid derivatives : (Analytical test of alcohol) HCl CH OCHOC CH CH CH O H ClOC CHacetate) (Ethyl ethanoate Ethyl 3 2| |3PyridineEthanol3 2chloride Ethanoyl | |3

Acylation :COOH CH CH OCHOC CH CH OCH H CHOC OOC CH3ethanoate Ethyl 3 2| |3 3 2anhydride Acetic 3| | | |3 (d) Reaction with grignard reagents :OMgBr CH H C MgBr H C OH CH3Ethane6 2omidebrmagnesium Ethyl 5 2alcoholMethyl3 (e) Reaction with ketene : form) (Keto| |3form) (enol |2 2R OOC CH R OO H C CH O C CH H O R(f) Reaction with isocyanic acid : (Urethane)ester amino| | | | |R OOC NH H R OOHC N HOC N H H O R(g) Reaction with ethylene oxide : hane dialkoxyet - 2 1,|2|2|2|2 2 22ORCHORCHOHCHOHCHO CH CH H O RO HROH (h) Reaction with diazomethane : (Ether)2 3 2 2N CH O R N CH OH R(i) Alkylation : 4 4 2HSO R R RO SO R ROH(ii) Reaction involving cleavage ofOH C|||| with removal or substitution of OH group Conc. H2SO4 (a)Reactionwithhydrogenhalides:Alcoholsgivealkylhalide.ThereactivityofHXisintheorderof HI>HBr>HCl and thereactivityofROHisintheorder ofallyl, benzyl >3> 2> 1.Thereaction follows a nucleophilic substitution mechanism. Groves process :O H X R HX ROHZnCl2anhydrous2 If alcohols react with HI and red phosphorus, alkane will be formed. O H I H C HI OH H CP2 2 6 2heatRed5 22Primary alcohols follow 2SNmechanism . O H X R R X X OH R2 2alcohol 1Protonated2OH - - - - - -o In secondary and tertiary alcohols, the SN1 mechanism operates OH R2OH RX R RX (b) Reaction with PCl5 :HX POX RX PX ROH3 5; X = Cl(Analytical test for alcohols) (c) Reaction with PCl3 : acid Phosphorus3 3chlorideAlkylde trichloriPhosphorus3Alcohol3 3 PO H RCl PCl ROH(d) Reaction with thionyl chloride [SOCl2] :HCl SO RCl SOCl ROH2Pyridine2 (e) Reaction with ammonia : amineTertiary3amine Secondary2aminePrimary236033 2 3 23 2N R NH R RNH NH ROHO AlROHO AlROHCO Alo (f) Reaction with HNO3 :O HOON O R HNO OH R2nitrite alkyl 3conc.Mechanism : 3 3NO H HNOR HHO R H H O RO H2|;nitrite alkyl 3OON O R NO R

(g) Reaction with H2SO4 [Dehydration of alcohol] : The elimination of water from a compound is known as dehydration.TheorderofcasedehydrationisTertiary>Secondary>primaryalcohol.Theproductsof dehydration of alcohols are depend upon the nature of dehydrating agents and temperature. H+ H2O Alcohol leading to conjugated alkene are dehydrated to a greater extent than those of alcohols leading to nonconjugated alkene. Thus dehydration is in order OHCH CH CH CHOHCH CH CH CH|3 2 3|3 2 alkene 2-333|33 33| |3 333||3333|||3\/24 2CHCHCCHC CHCH CHCH CH C CH CHCHCHCH C CHCHOH CHCH CH C CHHO HSO H 3 2CH CH CH CH O HSO HHOHCH CH CH CH24 2 |3 2 2 3 2 2CH CH CH CH tCH CH CH CHamoun More3 2 (iii) General reaction of alcohols (a) Reduction :H R HI OH R 2(b) Oxidation : Difference between 1, 2 and 3 alcohols. 1 acid Carboxylic|Aldehyde|2OOHC R OHC R OH RCH 2 O H CO RCOOH ROC R ROHCH RO CrO2 2conditions Drastic| |alcohol Secondary|3 3 O H CO COOH CHCHO C CHCHCH OH C CHO O2 2atoms) carbon ofnumber (Lesser acid Acetic 3) conditionstrongUnder(] [ 4atoms) carbon ofnumber(Lesser Acetone 3|3) conditionstrongUnder(] [ 4(Tertiary)alcohol butylTert.33||3 Note : 3 alcohols are resistant to oxidation, but on taking stronger oxidising agent they form ketone. 4 22 3SO HOH CH CH Conc. H2SO4 H2SO4110 140C 170 CH2 = CH2 Ethylene C2H5HSO4 Ethyl hydrogen sulphate C2H5O C2H5 Diethyl ether 3 33 3 33||||||3CH OH CHCH CH CHCH C C C CH H+/H2SO4 Shifting (H+) + (c) Catalytic oxidation/dehydrogentaion 1 2yde) (AcetaldehEthanal|3573 ,alcohol) (Pri.Ethanol||3H OHC CH H OHHC CHK Cu 2 (Acetone)Propanone32|3573 ,3alcohol) (Sec.Propanol 2-||3CHH O C CHCHH OHC CHK Cu 3O HCHCH C CHCHCHOH C CHK Cu2(Alkene) ene Methylprop 2-32|3573 ,alcohol) (Tert.ol 2- - an Methylprop 2-33||3 This is dehydration process and difference between 1, 2 and 3alcohols. (d) Oxidation through Fentons reagent :] [2 2 4O H FeSOMechanism H O OH Fe O H Fe32 22;O HCHOHH C C CH H O HCHOHCH C CH232||332||3 5 2, - hexandiol dimethyl- 5 2,33||232||333||232||3CHOH CH C CHCHOH CH C CHCHOHH C C CHCHOHH C C CH Important reagents used for oxidation of alcohols PCC[Pyridiniumchlorochromate) (3 5 6CrO Cl H N H C ]tooxidise1alcoholstoaldehydesand2 alcohols to ketones. PDC[Pyridinium dichromate 27 222 5 5) . ( O Cr NH H C ]to oxidise 1alcoholsto aldehydeand2alcohol to ketones. 4 2CrO H(chromic acid) to oxidise 1 alcohol to carboxylic acid. 4 2 3SO H CrO / Acetone to oxidise 2alcohol to ketones. Jonesreagents(chromicacidinaqueousacetonesolution)oxidise1alcoholtoaldehydeand2 alcohol to ketone without affecting (C = C) double bond. 2MnOselectivelyoxidisestheOHgroupofallylicandbenzylic1and2alcoholstogivealdehyde and ketone respectively. 4 2O Nin 3CHCl(fields) oxidises primary and secondary benzyl alcohol. (e) Self condensation : Guerbets reactionalcohol higher 2|2 2,2|2 25 2OH CHRCH CH CH R OH CHRCH H OH CH CH RH NaOC (f)Reactionwithcerricammoniumnitrate:ROHcolour Yellownitrate ammonium Cerric Redcoloursolutionof complex. This is analytical test for alcohols. (g)Iodoformtest:WhenafewdropsofalcoholarewarmedwithiodineandKOHyellowprecipitateof iodoform with characteristic smell is obtained. Any alcohol consistsCHOH CH3 group give iodoform test. Example :OH CH CH2 3, 3 3CH CHOH CH , 3 5 6CH CHOH H CSince reaction takes place with alkali solution as one of the reagentshence alkyl halide like Cl CH CH2 3 andRClCH CH|3 will also give this test. O H NaOI NaI I NaOH2 22 ; HI NaOH CHO CH NaOI OH CH CH 2 2 23 2 3 NaOH CHO CI NaOH CHO CH 3 33 3; HCOONa CHI NaOH CHO CIIodofiorm3 3 HCOOH CHI HCl CHO CI3 3 Other example (8) Individual members of monohydric alcohols Methanol (i) Preparation (a) By destructive distillation

CHOH CH3 (O) COCH3 KOH/I2 CHI3 + COONa O CHOHCH3 I2/NaOH O COCH3 I2 O COCI3 HCl H2O O COOH + CHI3 (b) From water gas : gas water 213002H CO O H CCo; alcohol Methyl 3300gases Compressed23 22 OH CH H COCO Cr ZnOo (c) From natural gas :OH CH O CH3 volume by ) 1 : 9 (2 42 2(ii) Physical properties (a) It is a colourless liquid and boils at 64.5 C. (b) It is miscible in water, good solvent for fats and oils. (c) It is inflammable and burns with a faint luminous flame. (d) It has pleasant smell and burning taste. (iii) Uses (a) For the manufacture of formaldehyde and formaline.O H O CH OH CHO Cr K2 2 37 2 2 (b) A 20% mixture of methyl alcohol and gasoline is a good motor fuel. (c) Use as an antifreeze for automobile radiators. (d) To denaturate ethyl alcohol, mixture is called methylated spirit. (e) In the preparation of dyes, medicines and perfumes. WOOD Destructive distillation Non-volatile residue (Charcoal)

Volatileproducts Passed into condenser Uncondensed gases (Wood gas) Distillate allowed to settle Lower coloured layer (Wood tar) Upper layer (Pyroligneous acid) Acetic acid 10%, methanol 2.5% and acetone 0.5% Passed through milk of lime and distilled Distillate (Methanol and acetone) Residue (Calcium acetate) Acetone (impure) (b.pt. 56 C)Purified bysodium bisulphite Distilled with H2SO4 Methanol (impure) (b.pt. 64.5 C)Purified by anhydrous Calcium chloride CH3COOH Acetic acidFractionally distilled Ethanol (i) Preparation (a) From Ethylene :OH H C O H H Catm CPO Ho5 270 , 3002 4 24 3Yield of ethyl alcohol is 95%. (b) From acetylene : de Acetaldehy3(Unstable) alcohol Vinyl 2| |60 , % 1%) 40 (2Acetylene| | |44 2CHO CHCHCHOHO HCHCHC HgSOSO Ho alcohol Ethyl 5 2140 1102 3OH H C H CHO CHCNio (c) Fermentation :This word is given by Lebeig. Fermentation process is exothermic. Ethanol is prepared by molasses and invert sugar molasses is the waste product in sugar industry.It is a mixture of sugar (30%) andinvertsugar(32-40%)combineformofglucoseandfructosecalledinvertsugar.Temperatureshouldbe 25-30C. low concentration (8-10%) is favourable. fructose6 12 6glucose5 12 6enzyme invertasecellyeast2 11 22 12O H C O H C O H O H C ;O H CO OH H C O H C2 2 5 2enzyme zymasecell yeast6 12 6 Certainamountsofinorganiccompoundsuchasammoniumsulphate,phosphateshouldbeadded. Oxygenisnecessaryforthegrowthofferments.Boricacid,mercurysaltsetc.shouldnotbepresentinthe solution as these retards the fermentation. (d) From starch :(wort) maltose11 22 12diastase2starch5 10 6n n ) ( 2 O H C O H O H Cn;glucose6 12 6maltosemaltose11 22 122 2 O H C O H O H Cenergy 22 2 6 2zymase6 12 6O H CO OH H C O H CBy this method ethanol prepared is 10-12% called wash.Raw spirit spirit rectified% 5 . 42% 5 . 955 2on distillatiFractionalO H OH H CManufacturing of ethyl alcohol (absolute) from rectified spirit called Azeotrophic distillation. Absolute alcohol is prepared by distillating rectified spirit with benzene. Thefirstfractionconsistsofconstantboilingmixtureofethylalcohol,waterandbenzene[18.5%+ 7.4% + 74.1%] and distills over at 64.8C. The second fraction consists of a boiling mixture of ethyl alcohol and benzene [32.4% + 67.6%] and distills atCo2 . 68 . Pure alcohol distills atCo3 . 78and known as absolute alcohol (100%). (ii) Properties : Same as monohydric alcohols. (iii) Uses (a) In the manufacture of alcoholic beverages. (b) As a preservative for biological specimens. (c) As a low freezing and mobile liquid in scientific apparatus such as thermometers and spirit levels. (d) In hospitals as an antiseptic. (e) As a petrol substitute (power alcohol). (9) Interconversion of monohydric alcohols (i) Primary alcohol into secondary alcohols alcohol) (2ol - 2 - Propan3|3aq.3|3Propene2 3alc 7 3alcohol) (1ol - -1 Propan7 32CHOHCH CH CHBrCH CH CH CH CH Cl H C OH H CKOH HBr KOH SOCl (ii) Secondary alcohol into tertiary alcohol alcohol) butyl(tert. ) (3ol 2- - pan Methtylpro 2-33||3,33||3 3| |3/] [alcohol) (2alcohol) propyl- (Isool 2- - Propan3|32 37 2 2OHCHCH C CHOMgBrCHCH C CH CHOC CH CHOHCH CHO H H MgBr CHH O Cr KO (iii) Primary alcohol into tertiary alcohol alcohol) butyl(tert.) (3 ol- 2 - an Methylprop - 233||3aq.33||3rules ff' Markowniko32|3n DehydratioHeat ,alcohol) butyl(Iso) (1 ol- 1 - an Methylprop - 232|34 2CHOH CH C CHCHBr CH C CHCHCH C CH OHCHCH CH CHKOH HBr SO H (iv) Lower alcohol into higher alcohol (ascent of series) atoms) carbon (2Ethanol 2 3 2 2 3Reduction) ( 43 3atom) carbon (1Methanol3OH CH CH NH CH CH CN CH I CH OH CHHONO H KCN HI (v) Higher alcohol into lower alcohol [Descent series] atom) carbon (oneMethanol3aq.3 4Heat3 3] [,atoms) carbon (2Ethanol 5 22 7 2 2OH CH Cl CH CH COONa CH COOH CH OH H CKOH Cl CaO NaOH NaOHOH O Cr K(10)Alcoholicbeverages:Liquorsused fordrinking purposescontainingethyl alcoholastheprincipal constituentarecalledalcoholicbeverages.Besidesalcohol,thesecontainlargeamountsofwater,colouring and flavouring materials. Alcoholic beverages are of two types : (i)Undistilledbeverages:Thesearepreparedfromfruitjuicesandgrains.Thosepreparedfrom grapes and other fruit juices are known as wines. Wines contain 18-20% of ethyl alcohol and are usedassuchafterfermentation,i.e.,withdistillation.Thenaturalwineswhenmadestrongerby the addition of rectified alcohol are known as fortified wines. Name Undistilled Percentage of alcohol Source Beer3-6Barley Cider2-6Apples Wine (Champagne)8-10Grapes Claret7-13Grape juice Port and Sherry (Fortified)14-24Grape juice (ii)Distilledbeverages:Thesearepreparedbythefermentationofmolasses,barley,maize,etc.The fermented liquor is then distilled. These contain a higher percentage of ethyl alcohol which may be as high as 50%. NameDistilledPercentage of alcoholSource Whisky35-40Malt Rum45-55Molasses Gin40-45Maize Brandy40-45Grape juice Cognac40-50Grape juice (11)Alcoholometry:Theprocess ofdetermining the percentageof alcoholina givensampleis known asalcoholometry.Analcoholwatermixturehavingspecificgravity0.91976at15Candcontaining57.1%of ethylalcoholbyvolumeor49.3%bymassiscalledproof-spirit.Asamplehavinghigherpercentageofethyl alcohol in comparison to proof-spirit is referred to as over-proof (O.P.) and the one having lower alcohol content thanproof-spiritisknownasunder-proof(U.P.).Thus15U.P.meansthat100mlofthesamplecontainsas much alcohol as 85ml of proof spirit. Similarly, 15 O.P. means that 100ml of the sample contains as much of alcohol as 115 ml of proof spirit. (12)Poweralcohol:Alcoholused forthe generation of poweriscalledpower alcohol.Generallyitis a mixtureof80%petroland20%absolutealcoholwithcosolventbenzene.Itischeaplyobtainedfromwaste petrol. (13) Methylated spirit : Ethyl alcohol containing 5 to 10% of methyl alcohol is known as methylated spirit ordenaturedspirit.Denaturingcanalsobedonebyadding 0.5%pyridine,petroleum naptha,rubberdistillate (caoutchoucine) or 4CuSO . (14)Toxicityofalcohols:Thetoxicityofalcoholsismainlyduetotheirbiologicaltooxidationtakes place in living organism. Methyl alcohol is highly toxic and its consumption causes, blindness and death. Et hyl alcoholisnontoxicbutproducesphysiologicaleffectdisturbingbrainactivityondrinking.Thecommercial alcoholismadeunfitfordrinkingbymixinginitcoppersulphate(whichgivesitscolour)andpyridine(which makes it foul smelling liquid). It is known as denaturation of alcohol. (15) Distinguish between primary, secondary and tertiary monohydric alcohols (i) Lucas test : A mixture of anhydrousHCl ZnCl conc.2 is called as Lucas reagent. Primary Cl CH R OH CH RO HZnCl HC2anhy. / conc.222 ppt. appears after heating Secondary Cl CH R OH CH RO HZnCl HCl2anhy. / conc.222 ppt. appears with in 5 minutes Tertiary Cl C R OH C RHCl ZnCl3/32 ppt. appears immediately (ii) Victor mayer test : Also known as RBW test.RBW Red, Blue, White test. Primary colour) (Red acid nitrolicof salt Sod.2||3acid Nitrolic 2||3 2 5 2 5 2 5 22 2NONaNO C CHNOHNO C CH NO H C I H C OH H CNaOH HONO AgNO I P Secondary NaOH HONO I PNONO C CH CHI CH CHOH CH2|2 3 2 3 2 3) ( ) ( ) (2 No reaction (Blue colour) Tertiary HONO AgNO I PCNO CH Cl CH COH CH2 3 3 3 3 3 3) ( ) ( ) (2 2 No reaction (colourless) Difference between methanol and ethanol MethanolEthanol (i)WhenCH3OHisheatedonCucoilitgives formalin like smell. (i) It does not give formalin like smell. (ii) When CH3OH is heated with salicylic acid in H-2SO4 (conc.) then methyl salicylate is formed which has odour like winter green oil. (ii) No such odour is given. (iii) It does not give haloform or iodoform test.(iii) It gives haloform test Dihydric alcohols.Thesearecompoundcontainingtwohydroxylgroups.Thesearedihydroxyderivativesofalkanes.Their general formulais 2 2 2O H Cn n.Thesimplestandmostimportantdihydricalcoholisethylene glycol.Theyare classified as,,.. glycols, according to the relative position of two hydroxyl groups. is 1, 2 glycol, is 1, 3 glycol. (1) Preparation (i) From ethylene : (a) Through cold dilute alkaline solution of Bayers reagent ; (b) With O2 in presence of Ag : glycol Ethylene2|2dil.oxide Ethylene2|2400 200 ,Catalyst2Ethylene2| |2221OH CHOH CHOCHCHOCHCHHClO HC Ag (c) With HOCl followed by hydrolysis : (Industrial method) 2Glycol2|2in chlorohydr Ethylene2|22| |23CO NaClOH CHOH CHCl CHOH CHHOClCHCHNaHCO (ii) From 1, 2 dibromo ethane [Lab method]:22|22 3 22|22 CO NaBrOH CHOH CHO H CO NaBr CHBr CH COONa CHOH CHOH CHOOCCH CHOOCCH CHCOOK CHBr CHBr CHNaOHKBrCOOH CH32|2diacetate Glycol 3 2|3 2232|22 23 Note : Vinyl bromide is formed as by product. Best yield of glycol can be obtained by heating 1, 2-dibromo ethane withCOOK CH3 in glacial acetic acid. (2) Physical properties (i) It is a colourless, syrupy liquid and sweet in taste.Its boiling point is 197C. (ii) It is miscible in water and ethanol in all proportions but is insoluble in ether. (iii) It is toxic as methanol when taken orally. (iv) It is widely used as a solvent and as an antifreeze agent. | | C=C (i) dil. KMnO4 (ii) dil. OH || C = C || OHOH (Syn-hydroxylation) RCO2OH H2O H+ OH || C C || OH (Anti-hydroxylation) || C C O H2CO2OH OH Anti addition(Trans) Syn-addition (cis) OH KMnO4/OH OH OH OH Conc. H2SO4 Alkaline HCO3H/H+ KmnO4 OH cis OH OH trans OH Pinacol; 2-3-dimethyl-2, 3 butanediol : Pinacol3 33||||3alk. dil ) (butene - 2 - Dimethyl - 3 2,3 33| |342CH CHOH OHCH C C C HCH CHCH C C C HKMnOO H O When pinacol react with mineral acid then pinacolone is formed. e) (Pinacolonbutanone - 2 - Dimethyl - 3 3,333|| | |3(Pinacol)butanediol - 3 2, - dimethyl - 2,33 33||||3CHCH OCH C C C HCH CHOH OHCH C C C HH. This arrangement is called as Pinacol-pinacolon rearrangement (3) Chemical properties Periodicoxidationofpolyhdroxyalcoholgives following information, (1)Thereiscleavageof(C C)bond.WhentwoOH groups or oxo groups are on adjacent carbon positions. CH3 | CH3 C OH | CH2OH Oxidised to ketone Oxidised to aldehyde Here cleavage takes place (2)BothCHOarepresentinonemoleculeindicating cyclic compound. OH OH HIO4 CH2 CH2 CH2 CH2 CHO CHO (3)OnonesidepresenceofCOOHgroupindicates keto group adjacent to (C OH) group in (C). HIO4 CH2 CH2 CH2 CH2 CHO COOH OH O (4) Formation of two molecule of glyoxalic acid indicate thatDiscycliccompoundoffourCatomwithC=O and C OH groups on both sides. OC CHOH || OC CHOH 18OHOH H5PO4 H2O18 O Due to formation of stable carbocation Dehydration CH2 CH2 OH O CH2 CH2 OH Diethylene glycol CH2 CH2 O O CH2 CH2 Dioxane Conc. H2SO4 CH2OH | CH2OH Glycol Na 50C CH2Cl | CH2 OH PCl5CH2 Cl | CH2 Cl 1,2 Dichloroethane CH2 ONa | CH2 OH CH2 ONa | CH2 ONa Dialkoxide (Disodium glycollate) Na 160C CH2Br | CH2 OH PBr3CH2Br | CH2Br 1, 2-dibromoethane I2 CH2 || CH2 Ethylene CH2I |CH2I Ethylene iodide (Unstable) CH2Cl | CH2OH CH2Cl | CH2Cl HCl 200C CH2ONO2 | CH2ONO2 Ethylene dinitrate CH2 CH2

O Ethylene oxide COOH | COOH Oxalic acid HCOOH Formic acid HCHO Formaldehyde CH2 || CH2OH Unstable CH3CHO Acetaldehyde Isomerisation PCl5PBr3PI3 HCl 160C CH2OOCCH3 | CH2OH CH3COOH CH2OOCCH3 | CH2OOCCH3 Glycoldiacetate CH3COOH Conc. HNO3 Conc. H2SO4 heat 600C Conc. HNO3 [O] KMnO4/H+HIO4 or (CH3COO)4Pb Dehydration ZnCl2CH3CHO (HCl) CH2O | CH2O Cyclic acetal CHCH3 CH3 O = C CH3 (HCl) CH2O | CH2O C CH3 CH3 Cyclic ketal (1,3 Dioxalane) Dioxalane formation provides a path of protecting a carbonyl group in reaction studied in basic medium in which acetals are not affected. The carbonyl compound may be regenerated by the addition ofperiodic acid to aqueous solution of the dioxalane or by acidic hydrolysis. HCHO R CO RCH OCH OCRROH CH OH H CO CRRHIO2 |42222| Aldehyde is more reactive than ketone in dioxalane formation. ; (4) Uses (i) Used as an antifreeze in car radiators.(ii) Used in the manufacture of dacron, dioxan etc. (iii) As a solvent and as a preservatives.(iv) As a cooling agent in aeroplanes. (v) As an explosives in the form of dinitrate. Trihydric alcohols.The only important trihydric alcohol is glycerol (propane-1, 2, 3-triol). It occurs as glycosides in almost all animal and vegetable oils and fats. (1) Preparation (i) From oils and fats acids FattyGlycerol22||steam2fat orOil 22||3 3 RCOOHOH CHOH CH OH CH O HOOCR CHOOCR CH OOCR CH ; acids fatty higherof salt Sodium22||Hydrolysisfat orOil 22||3RCOONaOH CHOH CH OH CHNaOHNaOHNaOHOOCR CHOOCR CH OOCR CH(ii) By fermentation of sugar : 2de Acetaldehy3Glycerol3 8 3YeastGlucose6 12 63 2CO CHO CH O H C C H CSO Na (iii) From propene [Modern method] Glycerol22||aq.hydrin monochloro -22||alcohol Allyl 22|| |) dil (chloride Allyl 22|| | 600propene32|| |2OH CHOH CHOH CHOH CHOH CH Cl CHOH CHCHCHCl CHCHCHCHCHCHNaOH HOCl NaOHCClo O CHO + CH2OH CH2OH O C O H O CH2 OH | CH2 OH O CH3 H3C OO O CH3 H3C O This part does not react due to steric hindrance (iv) From propenal : Glycerol2 2/2 2catalyst22 2 2OH CHOHCH HOCH OH CHCH CH CHCHO CHH O O H H (2) Physical properties (i) It is a colourless, odourless, viscous and hygroscopic liquid. (ii)Ithashighboilingpointi.e.,290C.Thehighviscosityandhighboilingpointofglycerolaredueto association through hydrogen bonding. (iii) It is soluble in water and ethyl alcohol but insoluble in ether. (iv) It is sweet in taste and non toxic in nature. (3) Chemical properties (i) Reaction with sodium : e glycerolat Disodium22||e temperaturRoom glycerol Monosodium22||e temperaturRoom 22||ONa CHONa CHOH CHONa CHOH CHOH CHOH CHOH CHOH CHNa Na (ii) Reaction with PCl5, PBr3 and PI3 (a) HCl POClCl CHCl CH Cl CH PClOH CHOH CH OH CH 3 3 33ropane) Trichlorop - 3 2, (1,richloride Glyceryl t22||522|| (b) 3 3opane Tribromopr - 3 2, 1,22||322||PO HBr CHBr CH Br CH PBrOH CHOH CH OH CH(c) 2iodide Allyl 22| ||(Unstable)22||322||ICHI CHCHI CHI CH I CH PIOH CHOH CH OH CH(iii) Reaction with HCl or HBr (44%) drin dichlorohy - ,Glycerol22||(56%) drin dichlorohy - ,Glycerol22|| 110of Excess(34%) hydrin monochloroGlycerol - 22||(66%) hydrin monochloroGlycerol - 22||11022||Cl CHCl CHOH CHCl CHOH CH Cl CHOH CHOH CH Cl CHCl CHOH CH OH CHOH CHOH CH OH CHCHClHClCoo (iv) Reaction with HI (a) 2iodide Allyl 22| ||(Unstable) e iodopropan - Tri - 1,2,322||Warm22||3 ICHI CHCHI CHI CH I CH HIOH CHOH CH OH CH(b) iodide Isopropyl 33||Propene32|| |Unstable32||iodide Allyl 22| ||2CHCHI CHCHCHCHCHI CHI CH HICHI CHCHHI I (v) Reaction with oxalic acid (a) At 110C Glycerol is formed acid Formic Glycerol22||formate mono Glycerol | |22||oxalate - mono Glycerol 22||110 100acid Oxalic 22||2 22COOH HOH CHOH CH OH CHHOC O CHOH CHOH CHCOOH OOC CHOH CH OH CH COOH HOOCOH CHOH CH OH CHO H COO HCo (b) At 260C, allyl alcohol is formed alcohol Allyl 22| |222| ||2|22||2 2CHOH CH CHOOC CHOH CHC OO CHHOOCHOOCOH CHOH CH OH CHCO O H (vi) Dehydration :O HCHCHOCHOH CHOH CH OH CHKHSO O P SO H2aldehyde allyl or Acrolene2| ||/ / conc.22||24 5 2 4 2 (vii) Oxidation CH2OH | CHOH | CH2OH [O] dil. HNO3CHO | CHOH | CH2OH Glyceraldehyde COOH | CHOH | CH2OH Glyceric acid COOH | CHOH | COOH Tartronic acid Fentons reagent CHO | CHOH | CH2OH Glyceraldehyde CH2OH | C = O | CH2OH Dihydroxy acetone + Glycerose [O] [O] KMnO4 acidified CH2OH | CO | CH2OH Dihydroxy acetone [O] CH2OH | CO | COOH Hydroxy Pyruvic acid [O] COOH | CO | COOH Mesoxalic acid [O] COOH | COOH Oxalic acid [O] CO2 + H2O 2HIO4 2CH2O + COOH +2HIO3 + H2O (viii) Reaction with nitric acid : (T.N.G.) rinitrate Glyceryl t22 22 22||conc.322||3 34 2O HONO CHONO CH ONO CH HNOOH CHOH CH OH CHSO H Dynamite is prepared from T.N.G. Dynamite:A mixture of T.N.G. and glyceryl dinitrate absorbed in kieselguhr is called dynamite.It wasdiscoveredbyAlfred.Nobelin1867.Itreleaseslargevolumeofgasesandoccupy10,900timesthe volume of nitroglycerine. 2 2 2 2 3 5 36 10 12 ) ( O N O H CO ONO H C Blasting gelatin : A mixture of glyceryl trinitrate and cellulose nitrate (gun cotton). Cordite : It is obtained by mixing glyceryl trinitrate with gun cotton and vaseline it is smokeless explosive. (4) Uses (a) As antifreeze in automobile radiator. (b) In the preparation of good quality of soap-hand lotions shaving creams and tooth pastes. (c) As a lubricant in watches. (d) As a preservatives. (e) As a sweetening agent in confectionary, beverages and medicines being non toxic in nature. (f) In manufacture of explosives such as dynamite. (5) Analytical tests of glycerol (i)Acroleintest:Whenglycerolisheatedwith 4KHSOaveryoffensivesmellisproducedduetoformationof acrolein. Its aqueous solution restores the colour of schiffs reagent and reduces Fehling solution and Tollens reagent. (ii)Dunstanstest:Adropofphenophthaleinisaddedapproximately5mlofboraxsolution.Thepinkcolour appears on adding 2-3 drops of glycerol, pinkcolourdisappears. The pink colour appearson heating and disappears on cooling again. Unsaturated alcohols.(1) Preparation (Allyl alcohol) (i) From allyl halide : alcohol Allyl 2 2 2 2 2HBr OH CH CH CH O H Br CH CH CH(ii) By heating glycerol with oxalic acid : alcohol Allyl 22| || 2Heat22| ||2|22||22CHOH CHCHOOC CHOH CHC OO CHHOOCHOOCOH CHOH CH OH CHCOO H (2) Physical properties (a) It is colourless, pungent smelling liquid. (b) It is soluble in water, alcohol and ether in all proportion. (3) Chemical properties

Phenol (Carbolic acid), C6H5OH or Hydroxy benzene.ItwasdiscoveredbyRungeinthemiddleoilfractionofcoal-tardistillationandnameditcarbolicacid (carbo=coal,oleum=oil)orphenolcontaining5%waterisliquidatroomtemperatureandistermedas carbolic acid. It is also present in traces in human urine. (1) Preparation H2 Pt CH3CH2CH2OH 1-propanol CH2 = CH CH2OH (Allyl alcohol) CH2Br CHBrCH2OH 2, 3-dibromopropanol-1 Br2CH2BrCH2 CH2OH 3-Bromopropanol-1 HBr CH2OHCHClCH2OH Glycerol-monochlorohydrin HOCl CH2 OH CHOH CH2OH Glycerol Alk. KMnO4(O + H2O) CH2 = CH CH2OOCCH3 Allyl acetate CH3COOH CH2 = CH CH2Cl Allyl chloride HCl COOH | COOH Oxalic acid HCOOH Formic acid + Oxidation Na CH2 = CH CH2ONa CH2CH CH2 ||| BrBrOH CH2 CH COOH || BrBrZn dust (CH3OH) CH2 CH COOH Acrylic acid [O] HNO3 Br2(i)Frombenzenesulphonicacid:Sodiumsaltofbenzenesulphonicacidisfusedwithsodium hydroxide(NaOH)whensodiumphenoxideisformed.Sodiumphenoxideontreatmentwithdiluteacidor carbon dioxide yields phenol. The start can be made with benzene. Phenol5 6/ or / phenoxide Sodium5 6Fusesulphonate benzene Sodium3 5 6acid sulphonicBenzene3 5 6) uming (Benzene6 62 22 4 2OH H C ONa H C Na SO H C H SO H C H CO H COO H H NaOH NaOH f SO HThis is one of the laboratory methods for the preparation of phenol. Similarly methyl phenols (cresols) can be prepared. (ii)Frombenzenediazoniumchloride:Whenbenzenediazoniumchloridesolutioniswarmed, phenol is formed with evolution of nitrogen. The phenol from solution is recovered by steam distillation. In this case also, benzene can be taken as the starting material. This is also a laboratory method. Phenol5 6Warmchloride diazonium Benzene2 5 65 0 ,Aniline2 5 6/ne Nitrobenze2 5 645 ,Benzene6 62 24 23OH H C Cl N H C NH H C NO H C H CO HC HClNaNO HCl SnC SO HHNOo o Note : Diazonium salts are obtained from aniline and its derivatives by a process called diazotisation. (iii) FromGrignardreagent:Chlorobenzene orbromobenzene is first converted into phenyl magnesium halide in presence of dry ether. The Grignard reagent on reaction with oxygen and subsequent hydrolysis by a mineral acid, yields phenol. Phenol5 6 5 6 bromide magnesium Phenyl 5 6Etherne Bromobenze5 62 2OH H C OMgBr H C MgBr H C Mg Br H CHO H O (iv) From salicylic acid : When salicylic acid or its sodium salt is distilled with soda lime, decarboxylation occurs and phenol is formed. (v) Middle oilof coal tar distillation:Middle oil of coal-tar distillation has naphthalene and phenolic compounds. Phenolic compounds are isolated in following steps. Step I : Middle oil is washed with 4 2SO H . It dissolves basic impurities like pyridine (base). Step II : Excessive cooling separates naphthalene (a low melting solid) StepIII:FiltrateofstepIIistreatedwithaqueousNaOHwhenphenolsdissolveasphenoxides.Carbondioxideis then blown through the solution to liberate phenols. 3 2 5 6,2 5 6 5 62 2CO Na OH H C O H ONa H C NaOH OH H CO H CO Step IV : Crude phenol (of step III) is subjected to fractional distillation. (vi) Raschigs process : Chlorobenzene is formed by the interaction of benzene, hydrogen chloride and air at 250C in presence of catalyst cupric chloride and Ferric chloride it is hydrolysed by superheated steam at 425C to form phenol SO3H CH3 p-Toluene sulphonic acid OK CH3 OH CH3 p-Cresol Solid KOHFuse H+/H2O NH2 CH3 m-Toluidine HNO2 N2Cl CH3 m-Toluene diazonium chloride HO2 OH CH3 m-Cresol OH COOH Salicylic acid + 2NaOH CaO OH Phenol + Na2CO3 + H2O Crude phenols fractional distillation180C 190-203C 211-235C o, m, p-cresols xylols (hydroxy xylenes) and HCl. This is one of the latest methods for the synthesis of phenol. HCl may be again used to convert more of benzene into chlorobenzene. O H Cl H C O HCl H CCFeCl CuClo2ene Chlorobenz5 6250/2Benzene6 63 221;HCl OH H C O H Cl H CCoPhenol5 6425steam2ene Chlorobenz5 6 (vii) Dow process : This process involves alkaline hydrolysis of chlorobenzene. Large quantities of phenol are formed by heating chlorobenzene with a 10% solution of caustic soda or sodium carbonate at 300C under a very high pressure (200 atm). O H NaCl ONa H C NaOH Cl H CCo2 5 6 pressure High300ene Chlorobenz5 62sodium phenoxide on treatment with mineral acid yields phenol. 4 2 5 6 4 2 5 62 2 SO Na OH H C SO H ONa H C(viii) Oxidation of benzene : This is the latest method for the manufacture of phenol. The mixture of benzene and air is passed over vanadium pentaoxide at 315C. Benzene is directly oxidised to phenol. OH H C O H CCO Vo5 63152 6 62 25 2 (ix) Oxidation of isopropylbenzene[Cumene] : Cumene is oxidised with oxygen or air into cumene hydroperoxide in presence of a catalyst. This is decomposed by dilute sulphuric acid into phenol and acetone.

(2) Physical properties (i) Phenol is a colourless crystalline, deliquescent solid. It attains pink colour on exposure to air and light. (ii) They are capable of forming intermolecular H-bonding among themselves and with water. Thus, they have high b.p. and they are soluble in water. Due to intermolecular H- bonding and highdipole moment, m.p. and b.p. of phenol are much higher than that of hydrocarbon of comparable molecular weights. AlCl3AlCl3+ CH3CH2CH2Cl + CH3CH = CH2 CH Cumene CH3 H3C O2 Catalyst O OH | C(CH3)2 Cumene hydroperoxide H2O/H+ OH Phenol + (CH3)2CO Acetone H O-------H O-------H O-------H O------- +

+

+

+

(intermolecular H-bonding among phenol molecules) H H | |H O-------H O-------H O-------H O------- +

+

+ + (crossed intermolecular H-bonding between water and phenol molecules) CompoundsMolecular weightBoiling pointMelting point Phenol 194 mol g182C41C Toluene 192 mol g111C95C (iii) It has a peculiar characteristic smell and a strong corrosive action on skin. (iv)Itissparinglysolubleinwaterbutreadilysolubleinorganicsolventssuchasalcohol,benzeneand ether. (v) It is poisonous in nature but acts as antiseptic and disinfectant. (3) Chemical properties (i) Acidic nature : Phenol is a weak acid. The acidic nature of phenol is due to the formation of stable phenoxide ion in solution. O H OH H C2 5 6 O H O H C3ion Phenoxide5 6 The phenoxide ion is stable due to resonance. The negative charge is spread throughout the benzenering. This charge delocalisation is a stabilising factor in the phenoxide ion and increase acidity of phenol. [No resonance is possible in alkoxide ions (RO) derived from alcohols. The negative charge is localised on oxygen atom. Thus alcohols are not acidic]. Note : Phenols are much more acidic than alcohols but less so than carboxylic acids or even carbonic acid. This is indicated by the values of ionisation constants. The relative acidity follows the following order Alcohols18Water14Phenol5 610acid Carbonic 3 27acid Carboxylic5) 10 ( ) 10 ( ) 10 ( ) 10 ( ) 10 ( ) approx. (ROH HOH OH H C CO H RCOOHKa Effects of substituents on the acidity of phenols : Presence of electron attracting group, (e.g.,2NO , X, 3NR , CN,CHO,COOH)onthebenzeneringincreasestheacidityofphenolasitenablestheringtodrawmoreelectrons fromthephenoxyoxygenandthusreleasingeasilytheproton.Further,theparticulareffectismorewhenthe substituent is present on o- or p-position than in m-position to the phenolic group. The relative strengths of some phenols (as acids) are as follows : p-Nitrophenol > o-Nitrophenol > m- Nitrophenol > Phenol Presenceofelectronreleasinggroup,(e.g., 3CH , 2 3 5 2, , NR OCH H C )onthebenzeneringdecreasesthe acidityofphenolasitstrengthensthenegativechargeonphenoxyoxygenandthusprotonreleasebecomesdifficult. Thus, cresols are less acidic than phenol. However, m-methoxy and m-aminophenols are stronger acids thanphenol because of I effect and absence of +R effect. m-methoxy phenol > m-amino phenol > phenol > o-methoxy phenol > p-methoxy phenol Greater the value of aKor lower the value of apK , stronger will be the acid. Some other examples of acidic nature of phenols are, Chloro phenols : o- > m- > p- Cresols : m- > p- > o- Dihydric phenol : m- > p- > o- The acidic nature of phenol is observed in the following : O ..O O ..O .. (a) Phenol changes blue litmus to red. (b) Highly electropositive metals react with phenol. 2 5 6 5 62 2 2 H ONa H C Na OH H C(c) Phenol reacts with strong alkalies to form phenoxides.O H ONa H C NaOH OH H C2 5 6 5 6 However, phenol does not decompose sodium carbonate or sodium bicarbonate, i.e., 2COis not evolved because phenol is weaker than carbonic acid. (ii) Reactions of OH group (a) Reaction with FeCl3 : Phenol gives violet colouration with ferric chloride solution (neutral) due to the formation of a coloured iron complex, which is a characteristic to the existence of keto-enol tautomerism in phenols (predominantly enolic form). ; This is the test of phenol. (b)Etherformation:Phenolreactswithalkylhalidesinalkalisolutiontoformphenylethers(Williamsons synthesis). The phenoxide ion is a nucleophile and will replace halogenation of alkyl halide. O H ONa H C NaOH OH H C2 phenoxide Sod.5 6 5 6; NaCl OCH H C ClCH ONa H C(Anisole) ethernylMethyl phe3 5 6 3 5 6 KI H C O H C H IC OK H C(Phenetol) benzene Ethoxy5 2 5 6 5 2 5 6;ether phenylIsopropyl 2 3 5 6chloride Isopropyl 2 3 5 6) ( ) ( CH HC O H C CH HC Cl ONa H CEthers are also formed when vapours of phenol and an alcohol are heated over thoria) (2ThOor 3 2O Al . benzene Methoxy3 5 6,3 5 62CH O H C HOCH OH H CThO (c)Esterformation:Phenolreactswithacidchlorides(oracidanhydrides)inalkalisolutiontoformphenylesters (Acylation). This reaction (Benzoylation) is called Schotten-Baumann reaction. O H ONa H C NaOH OH H C2 5 6 5 6; NaCl OOCCH H C CHOC Cl ONa H Cacetate Phenyl 3 5 6chloride Acetyl 3| | phenoxide Sodium5 6 COOH CH OOCCH H C O CO CH OH H CNaOH3(ester) acetate Phenyl 3 5 6anhydride Acetic 2 3 5 6) ( ;O H NaCl H COC O H C H COC Cl OH H CNaOH2zoate Phenyl ben5 6| |5 6chloride Benzoyl 5 6| |5 6 Thephenylestersontreatmentwithanhydrous 3AlClundergoesFriesrearrangementtogiveo-andp-hydroxy ketones. (d)ReactionwithPCl5:Phenolreactswith 5PCltoformchlorobenzene.Theyieldofchlorobenzeneispoorand mainly triphenyl phosphate is formed. HCl POCl Cl H C PCl OH H C3 5 6 5 5 6; HCl PO H C POCl OH H C 3 ) ( 34 3 5 6 3 5 6 OH Enol O Keto OH 6+ FeCl3 3H+ +Fe O 6 3 + 3HCl OOCCH3 Phenyl acetate AlCl3 (anhydrous) heat + OH COCH3 OH COCH3 hydroxy acetophenone p o- (e) Reaction with zinc dust : When phenol is distilled with zinc dust, benzene is obtained. ZnO H C Zn OH H C6 6 5 6 (f) Reaction with ammonia : Phenol reacts with ammonia in presence of anhydrous zinc chloride at 300C or 3 3 2 4/ ) ( NH SO NHat 150C to form aniline. This conversion of phenol into aniline is called Bucherer reaction. O H NH H C NH OH H CCZnClo2Aniline2 5 63003 5 62 (g) Action of P2S5 : By heating phenol with phosphorus penta sulphide, thiophenols are formed. 5 2Thiophenol5 6 5 2 5 65 5 O P SH H C S P OH H C(iii) Reactions of benzene nucleus : The OH group is ortho and para directing. It activates the benzene nucleus. (a)Halogenation:Phenolreactswithbromineincarbondisulphide(or 3CHCl )atlowtemperaturetoform mixture of ortho and para bromophenol. ; Phenol forms a white precipitate with excess of bromine water yielding 2, 4, 6-tribromophenol. (b)Sulphonation:Phenolreactswithconc. 4 2SO Hreadilytoformmixtureoforthoandparahydroxybenzene sulphonic acids. Atlowtemperature(25C),theortho-isomeristhemajorproduct,whereasat100C,itgivesmainlythepara-isomer. (c) Nitration :Phenol reacts with dilute nitric acid at5-10C to form ortho and para nitro phenols, but theyield is poor due to oxidation of phenolic group. The OH group is activating group, hence nitration is possible with dilute nitric acid. Itisbelievedthatthemechanismoftheabovereactioninvolvestheformationofo-andp-nitrosophenolwith nitrous acid,) (2 2HCl NaNO HNOat 0-5C, which gets oxidised to o- and p- nitrophenol with dilute nitric acid. + Br2 OH (CS2) OH Br o-Bromophenol + p-Bromophenol OH Br +3HBr +3Br2 OHOH Br Br Br 2, 4, 6-Tribromophenol OH (H2SO4) OH SO3H o-Hydroxybenzene sulphonic acid + OH SO3H p-Hydroxybenzene sulphonic acid OH NO2 p-Nitrophenol OHOH NO2 o-Nitrophenol + HNO3(dil.) (5-10C) OH NO p-Nitrosophenol OHOH NO o-Nitrosophenol + HONO (0-5C) [O] HNO3 (Dil.) Nitrophenol + OH NO2 p- OH NO2 o- However,whenphenolistreatedwithconcentrated 3HNOinpresenceofconcentrated 4 2SO H ,2,4,6-trinitrophenol (Picric acid) is formed. Togetbetteryieldofpicricacid,firstsulphonationofphenolismadeandthennitrated.PresenceofH SO3 group prevents oxidation of phenol. (d)Friedel-Craftsreaction:Phenolwhentreatedwithmethylchlorideinpresenceofanhydrousaluminium chloride, p-cresol is the main product. A very small amount of o-cresol is also formed. RX and 3AlClgive poor yields because 3AlClcoordinates with O.So Ring alkylation takes place as follows, HCl OAlCl H C AlCl OH H C2 5 6 3 5 6 Thus to carry out successful Friedel-Crafts reaction with phenol it is necessary to use a large amount of 3AlCl . The Ring alkylation takes place as follows : 2 34 6or 2 32 35 6) (\/- and -) (4 2CH CHOHH C p oOH CH CHCH CH CHOH H CHFSO H (e) Kolbe-Schmidt reaction (Carbonation) : This involves the interaction of sodium phenoxide with carbon dioxide at 130-140C under pressure of 6 atmospheres followed by acid hydrolysis, Salicylic acid (o-Hydroxy benzoic acid) is formed. OHOH NO2 2, 4, 6-Trinitrophenol (picric acid) O2N NO2 HNO3 (conc.) H2SO4(conc.) + CH3Cl OH CH3 p-Cresol (major product) OH + AlCl3OH CH3 o-cresol OH anhydrous AlCl3 + OH COCH3 OH COCH3 + CH3COCl Acetyl chloride hydroxy acetophenone ortho The probable mechanism is :H O H C OH H C5 6 5 6 At higher temperature (250-300C), p-isomer is obtained. (f)Reimer-Tiemannreaction:Phenol,onrefluxingwithchloroformandsodiumhydroxide(aq.)followedbyacid hydrolysisyieldssalicylaldehyde(o-hydroxybenzaldehyde)andaverysmallamountofp-hydroxybenzaldehyde. However, when carbon tetrachloride is used, salicylic acid (predominating product) is formed. The electrophile is dichloromethylene 2: CClgenerated from chloroform by the action of a base. 3CHCl OH carbene Dichloro2 3: : CCl Cl Cl C HOHReimer-Tiemann reaction involves electrophilic substitution on the highly reactive phenoxide ring. H O H C OH H CPhenoxide5 6 5 6 Attack of electrophile) (:2CCl ; ONa + CO2 130-140C 6 atm OCOONa Sodium phenyl carbonate RearrangementOH COONa Sodium salicylate OH COOH Salicylic acid H+ H2O CH3OH CH3COCl OH COOC6H5 Salol OCOCH3 COOH Aspirin OH COOCH3 Winter green OH OH CHCl2 NaOH ONa CHO H+ H2O OH CHO Salicylaldehyde CHCl3 NaOH(aq.) 60C OH CCl3 NaOH ONa COONa H+ H2O OH COOH Salicylic acid CCl4 NaOH(aq.) 60C O O C O || O H H+ +H+ OH C O || O H+ OH COOH + C = O || O O CHCl2 O + : CCl2 (g)Gattermannsreaction:Phenol,whentreatedwithliquidhydrogencyanideandhydrochloricacidgasin presence of anhydrous aluminium chloride yields mainly p-hydroxy benzaldehyde (Formylation). NH ClCH N HC HClAlCl3 (h)Mercuration:Phenolwhenheatedwithmercuricacetateundergoesmercurationtoformo-andp-isomers. (i)Hydrogenation:Phenol,whenhydrogenatedinpresenceofanickelcatalystatabout150-200C, forms cyclohexanol. (iv) Miscellaneous reactions (a)Couplingreactions:Phenolcoupleswithbenzenediazoniumchlorideinpresenceofanalkaline solution to form a red dye (p-hydroxy azobenzene). O CHCl2 + 2NaOH Hydrolysis O CH(OH)2 H2O O CHO O CHO + H+ OH CHO Salicylaldehyde OH CH = NH OH OH CHO p-Hydroxy benzaldehyde H2O NH3 + ClCH = NH AlCl3HCl + (CH3COO)2Hg OH OH HgOCOCH3 p-Hydroxy phenyl mercuric acetate OH HgOCOCH3 o-Hydroxy phenyl mercuric acetate +OH Phenol (C6H5OH) + 3H2 Ni150-200C OH Cyclohexanol (C6H11,OH) (used as a good solvent) Phenolcoupleswithphthalicanhydrideinpresenceofconcentrated 4 2SO Htoformadye, (phenolphthalein) used as an indicator. (b)Condensationwithformaldehyde:Phenolcondenseswithformaldehyde(excess)inpresenceof sodium hydroxide or acid) (Hfor about a week to form a polymer known as bakelite (a resin). (c)Liebermannsnitrosoreaction:Whenphenolisreactedwith 2NaNOandconcentrated 4 2SO H ,it gives a deep green or blue colour which changes to red on dilution with water. When made alkaline withNaOH original green or blue colour is restored. This reaction is known as Liebermannsnitroso reaction and is used as a test of phenol. (d) Oxidation :Phenol turns pink or red or brown on exposure to air and light due to slow oxidation. The colour is probably due to the formation of quinone and phenoquinone. Butonoxidationwithpotassiumpersulphateinalkalinesolution,phenolforms1,4-dihydroxybenzene (Quinol). This is known as Elbs persulphate oxidation. N = NCl + Benzenediazonium chloridePhenol OH NaOH HCl N = NOH p-Hydroxyazobenzene Conc. H2SO4 (H2O) O || C OH C OH || O Phthalic acid H OH H OH O || C C || O O Phthalic anhydride Phenol (2 molecules) OH OH O || C C O Phenolphthalein + OH OH CH2OH o-hydroxy benzyl alcohol NaOH + CH2O OH CH2OH p-hydroxy benzyl alcohol Condensation with HCHOcontinues give OH CH2 CH2 CH2 OH CH2 CH2 Polymer Bakelite (a resin) HONO OH p-Nitrosophenol OHNOONOH Quinoxim OH O2 by air or CrO3 OO p-benzoquinone C6H5OH OH - - - OO - - - HO Phenoquinone (pink) C6H5OHor [O] CrO2Cl2+ H2O O p-benzoquinone O OH Phenol OH OH Quinol K2S2O8 in alkaline solution OH Phenol ON OH + HOH H2SO4H2O ONOH NaOH H2O Sod. Salt of indophenol (blue) Indo phenol (Red) (4) Uses : Phenol is extensively used in industry. The important applications of phenol are : (i)Asanantisepticinsoaps,lotionsandointments.ApowerfulantisepticisDettolwhichisaphenol derivative (2, 4-dichloro-3, 5-dimethyl phenol). (ii) In the manufacture of azo dyes, phenolphthalein, etc. (iii) In the preparation of picric acid used as an explosive and for dyeing silk and wool. (iv)Inthemanufactureofcyclohexanolrequiredfortheproductionofnylonandusedasasolventfor rubber and lacquers. (v) As a preservative for ink. (vi) In the manufacture of phenol-formaldehyde plastics such as bakelite. (vii) In the manufacture of drugs like aspirin, salol, phenacetin, etc. (viii) For causterising wounds causedby the bite of mad dogs. (ix) As a starting material for the manufacture of nylon and artificial tannins. (x) In the preparation of disinfectants, fungicides and bactericides. (5)Testsofphenol:(i)Aqueoussolutionofphenolgivesavioletcolourationwithadropofferric chloride. (ii) Aqueous solution of phenol gives a white precipitate of 2, 4, 6-tribromophenol with bromine water. (iii) Phenol gives Liebermanns nitroso reaction. Phenol in conc. sulphuric acid of water Excess2NaNO Red colour (Excess)NaOH Blue colour (iv) Phenol combines with phthalic anhydride in presence of conc.4 2SO Hto form phenolphthalein which gives pink colour with alkali, and used as an indicator. (v) With ammonia and sodium hypochlorite, phenol gives blue colour. Difference between phenol and alcohol PropertyPhenol (C6H5OH)Alcohol (C2H5OH) OdourTypical phenolic odourPleasant alcoholic odour Nature, reaction with alkaliAcidic,dissolvesinsodiumhydroxide forming sodium phenoxide. Neutral, no reaction with alkalies. Reaction with neutral FeCl3Givesvioletcolourationdueto formation of complex compound. No reaction. Reaction with halogen acidsNo reaction with halogen acids.Forms ethyl halides. OxidationPink or brown colour due to formation of quinone and phenoquinone. Undergoesoxidationtogive acetaldehyde and acetic acid. Reaction with HCHOForms polymer (bakelite).No reaction. Liebermanns nitroso reactionPositive.Does not show. Couplingwithbenzenediazonium chloride Forms azo dye.Does not form any dye. Reaction with PCl5Mainly forms triphenyl phosphate.Forms ethyl chloride Iodoform testDoes not show.Positive.

Derivatives of phenol.NITROPHENOLS (1) Preparation (i) Phenol easily undergoes nitration. Ortho and para nitrophenols are obtained by nitration of phenol with dilute 3HNOin cold. Ortho isomer is separated by steam distillation as it is steam volatile. OH OH NO2 o-isomer(steam volatile) Dil. HNO3OH NO2 p-isomer(non-volatile) + (ii) o- and p-forms are also obtained by treating chloro or bromo nitrobenzene with caustic alkali at 120C. l nitropheno - and -24 6ne nitrobenze chloro - and -24 6p oNaOHp oNOOHH CNOClH C(iii)Whenheatedwithsolidpotassiumhydroxide,nitrobenzeneproducesamixtureofo-andp-nitrophenols. l nitropheno - and -24 6heatSolidne Nitrobenze2 5 6p oKOHNOOHH C NO H C(iv)m-Nitrophenolisobtainedfromm-dinitrobenzene.Oneofthenitrogroupisconvertedinto 2NHgroup which is diazotised. The diazonium compound on boiling yields m-nitrophenol. (2)Properties:o-Nitrophenolisayellowcolouredcrystallinecompound,whilem-andp-isomersare colourless crystalline compounds. 114 97 45 C) ( m.pt.Isomer para meta ortho the lowest melting point ofo-isomer is due tointramolecularhydrogenbondingwhereas meta and para isomers possess intermolecular hydrogen bonding and thus, they have higher melting points. They are stronger acids than phenol. The order is : p-isomer > o-isomer > m-isomer > phenol Whenreduced,theyformcorrespondingaminophenols.o-andp-Nitrophenols reactwithbrominewater to form 2, 4, 6-tribromophenol by replacement of nitro group. Picric acid (2, 4, 6-trinitrophenol) (1) Preparation : It is obtained when phenol is treated with conc. 3HNO . However, the yield is very poor. It is prepared on an industrial scale : (i) From chlorobenzene

NH4HS or Na2S NO2 m-Dinitrobenzene NO2 NO2 m-Nitroaniline NH2 NaNO2/HCl 0-5C NO2 m-Nitrobenzene diazonium chloride N2Cl H2O NO2 m-Nitrophenol OH Cl OH NO2 Picric acid (2, 4, 6-Trinitrophenol) O2N NO2 HNO3 H2SO4 Chlorobenzene 2, 4-Dinitrochlorobenzene Cl NO2 NO2 Aq. Na2CO3 OH NO2 NO2 HNO3 H2SO4 OH Br Br Br 2isomer - or-24 6\/Brp oNOOHH C2,4,6 Tribromophenol (ii) From phenol through disulphonic acid (iii)Itmaybepreparedinthelaboratorybyoxidationofs-trinitrobenzene(TNB)withpotassium ferricyanide. (2) Properties : It is a yellow crystalline solid, m.pt. 122C. it is insoluble in cold water but soluble in hot water and in ether. It is bitter in taste. Due to the presence of three electronegative nitro groups, it is a stronger acidthanphenolanditspropertiesarecomparabletothecarboxylicacid.Itneutralisesalkaliesand decomposes carbonates with evolution of carbon dioxide. Drypicricacidaswellasitspotassiumorammoniumsaltsexplodeviolentlywhendetonated.Itreacts with 5PClto form picryl chloride which on shaking with 3NHyields picramide. When distilled with a paste of bleaching powder, it gets decomposed and yields chloropicrin, 2 3NO CCl , as one of the products and is thus employed for the manufacture of tear gas. It forms yellow, orange or red coloured molecular compounds called picrates with aromatic hydrocarbons, amines and phenols which are used for characterisation of these compounds. Note : Picrates are explosive in nature and explode violently when heated. These are prepared carefully. (3) Uses : It is used as a yellow dye for silk and wool, as an explosive and as an antiseptic in treatment of burns. Catechol (1, 2-Dihydroxy benzene) (1) Preparation (i) By fusion of chlorosubstituted phenolic acid with caustic soda. or by hydrolysis of o-dichlorobenzene or o-chlorophenol with dilute NaOH solution at 200C and in the presence of copper sulphate catalyst. ; OH NO2 Picric acid O2N NO2 H2SO4 OH Phenol Phenol disulphonic acid OH SO3H SO3H HNO3 Picric acid OH NO2 O2N NO2 Ke3Fe(CN)6NO2 O2N NO2 + [O] OH NO2 O2N NO2 NH3 PCl5H2O Picryl chloride Cl NO2 O2N NO2 Picramide NH2 NO2 O2N NO2 OH Cl COOH NaOH OH OH Catechol + CO2 + NaCl Cl Cl NaOH 200C, Cu2+ONa ONa H+/H2O OH OH (ii)Byfusingalkalisaltofo-phenolsulphonicacidwithcausticalkaliandthenhydrolysingtheproduct with mineral acid. (iii) It may be conveniently prepared in the laboratory by treating salicylaldehyde with alkaline 2 2O H . (2)Properties:Itisacolourlesscrystallinesolid,m.pt.105C.itissolubleinwater.Itisaffectedon exposure to air and light. It acts as a reducing agent as it reduces Tollens reagent in cold and Fehlings solution on heating. With silver oxide it is oxidised to o-benzoquinone. It forms insoluble lead salt (white ppt.) when treated with lead acetate solution and gives green colour with 3FeClwhichchangestoredonadding 3 2CO Nasolution.Itformsalizarindyestuffwhencondensedwith phthalic anhydride in the presence of sulphuric acid. (iii) Uses:It finds use as photographic developer, in the manufacture of alizarin and adrenaline hormone and as an antioxidant (inhibitor in auto oxidation) for preserving gasoline. Resorcinol (1, 3-Dihydroxy benzene) (1) Preparation : It is prepared by alkali fusion of 1,3, benzene disulphonic acid (Industrial method).

OH SO3K OK OK 2HCl OH OH + 3KOH + H2O2 + NaOH CHO OH Salicylaldehyde OH OH Catechol + HCOONa + H2O OH OH + Ag2O O O + 2Ag + H2O o-Benzoquinone SO3H SO3H NaOH Fuse ONa ONa HCl OH OH (H2O) O || C C || O OH OH Alizarin OH OH O || C C || O O + Phthalic anhydride Con H2SO4 (2) Properties : It is a colourless crystalline solid, m.pt. 110C. it is affected on exposure by air and light. It is soluble in water, alcohol and ether. It shows tautomerism. Its aqueous solution gives violet colour with 3FeCl. It reduces Fehlings solution and Tollens reagent on warming. With bromine water, it gives a crystalline precipitate, 2, 4, 6-tribromoresorcinol. On nitration, it forms 2, 4, 6-trinitro-1, 3-dihydroxybenzene. It condenses with phthalic anhydride and forms fluorescein. With nitrous acid, it forms 2, 4-dinitrosoresorcinol OH OH + 3Br2 OH OH BrBr Br + 3HBr OH OH HNO3 H2SO4OH OH NO2 NO2 O2N Styphnic acid Conc. H2SO42H2O O = CC O OH OH O Fluorescein Resorcinol (2 moles) H H O H OH OH OH O = CC = O + O Phthalic anhydride OH OH HNO2 OH OH NO NO O O NOH NOH Resorcinolbehavesasatautomericcompound.Thisisshownbythefactthatitformsadioximeanda bisulphite derivative. (3) Uses (i) It is used as antiseptic and for making dyes. (ii) It is also used in the treatment of eczema. 2, 4, 6-trinitroresorcinol is used as an explosive. Hydroquinone or quinol (1, 4-Dihydroxy benzene) (1)Preparation:Itisformedbyreductionofp-benzoquinonewithsulphurousacid ) (2 2 3 2SO O H SO H . (p-Benzoquinone is obtained by oxidation of aniline) (2)Properties:Itisacolourlesscrystallinesolid,m.pt.170C.itissolubleinwater.Italsoshows tautomerism. It gives blue colour with 3FeClsolution. OH OH Dienol form O O Diketo form O Quinol OH + H2SO4 HOO + SO2 + 2H2O H2SO3 + H2O NH2 [O] MnO2/H2SO4O O Fe/H2O [H] OH OH Quinol It acts as a powerful reducing agent as it is easilyoxidised top-benzoquinone. It reduces Tollens reagent and Fehlings solution. Due to this property, it is used as photographic developer. (3)Uses:Itisusedasanantiseptic,developerinphotography,inthepreparationofquinhydrone electrode and as an antioxidant. TrihydricPhenols:ThreetrihydroxyisomericderivativesofbenzenearePyrogallol(1,2,3),hydroxy quinol (1, 2, 4) and phloroglucinol (1, 3, 5). Pyrogallol is obtained by heating aqueous solution of gallic acid at 220C. Phloroglucinol is obtained from trinitrotoluene (TNT) by following sequence of reactions. Hydroxyquinol is prepared by the alkaline fusion of hydroquinone in air. OH HOOO p-Benzoquinone [O] FeCl3 OH OH OHHOOC Gallic acid heat 220C OH OH OH Pyrogallol + CO2 KMnO4 [O] CH3 NO2 NO2 O2N 2, 4, 6-trinitro toluene COOH NO2 NO2 O2N Fe/HCl [H] COOH NH2 NH2 H2N H2O/H+ 100C OH HOOH Phloroglucinol + CO2 + 3NH4Cl NaOH Fuse OH OH Quinol + O2 OH OH Hydroxy Quinol OH Thethreeisomersarecolourlesscrystallinecompounds.Allaresolubleinwaterandtheiraqueous solutionsgivecharacteristiccolourwith 3FeCl .Forexample,Pyrogallol-red;Hydroxyquinol-greenishbrown; Phloroglucinol-bluish violet. Alkaline solutions absorb oxygen rapidly from air. Uses of pyrogallol (i) As a developer in photography. (ii) As a hair dye. (iii) In treatment of skin diseases like eczema. (iv) For absorbing unreacted oxygen in gas analysis. Introduction of ether.Ethersareanhydrideofalcohols,theymaybeobtainedbyeliminationofawatermoleculefromtwo alcohol molecules. O H R O R R HO OH R2Ether

General formula isO H Cn n 2 2 (1) Classification : It may be divided in two category. (i) Aliphatic ethers : Both R of ether are alkyl group. Example : ether Dimethyl 3 3CH O CH , ether propylIsopropyl 3 2 23||3CH CH CHCH OHC CH . (ii) Aromatic ethers : In which either one or both R of ether are aryl groups. Example : ether nylMethyl phe3 5 6CH O H Cor ether Diphenyl 5 6 5 6H C O H CAromatic ethers are divided in two category. (a) Phenolic ethers : Ethers in which one of the group is aryl and other one is alkyl. Example : ether nylmethyl phe3 5 6CH O H C . (b) Diaryl ether : In which both the groups are aryl group. Example : ether Diphenyl 5 6 5 6H C O H C(iii) Symmetrical and unsymmetrical ethers, (a) An ether in which both the R are same known as symmetrical ethers. Example : ether Dimethyl 3 3CH O CH , ether Diphenyl 5 6 5 6H C O H C . (b) An ether in which the both R are different called unsymmetrical ethers or mixed ethers. Example: ether methylEthyl 5 2 3H C O CH and ether nylMethyl phe5 6 3H C O CH . (2) Structure : The oxygen atom in ether is 3sphybridised. Two of the hybrid orbitals overlap with hybrid orbital (one each) of two carbon atoms to form sigma bonds. C O C. The bond angle is o110 . Besides the open chain saturated homologous series, there are numerous organic compounds in which O functional group is present. These compounds are also termed ethers. ed} {unsaturatether ylMethyl vin2 3CH OCH CH ; {cyclic}oxide Ethylene2 2OCH CH ; furan hydro Tetra2|22|2OCHCHC HC H ; ; ether) enyl(Methyl phAnisole3 5 6OCH H C(3) Nomenclature : There are two systems for naming ethers. H2C | H2C CH2 | CH2 O O Dioxan O RR LONE PAIRS 110 (i)Commonnames:Whenboththealkylgrouparesame,theprefixdi-isused.Incaseof unsymmetrical ethers two alkyl groups are named in alphabetical order. Example : ether methylDi3 3OCH CH , ether ylEthyl prop7 3 5 2H OC H C . (ii) IUPAC system : Ethers are named as alkoxy alkanes. (a) The ethernal oxygen is taken with smaller alkyl group. Example : Methoxy3O CH ; group Ethoxy5 2O H C . (b) The R group having the longest carbon chain is chosen as the parent alkane. Example : ethane Methoxy5 2 3H C O CH , Note : In case of simple ethers common names are also accepted in IUPAC system. (4) Isomerism : Ether show the following types of isomerism : (i) Chain isomerism Example : butane methoxy - 13 2 2 2 3CH CH CH CH O CH , pane methyl pro - 2 - methoxy - 133|2 3CHCHH C CH O CH . (ii) Functional isomerism Example : Ethanol2 3ether Dimethyl 3 3OH CH CH CH O CH ,(iii) Metamerism Example : propane Methoxy3 2 2 3ethane Ethoxy3 2 2 3CH CH CH O CH CH CH O CH CH General methods of preparation of ethers.(1) From alkyl halides (i) Williamsons synthesis : It is the laboratory method for the preparation of ethers. It is a nucleophilic substitution reaction and proceed through 2SNmechanism. NaX R RO X R RONaNaI H OC CH I CH ONa H Cether methylEthyl 5 2 3 3ethoxide Sodium5 2NaBr H OC H C Br H C ONa H Cne Ethoxyetha5 2 5 2ide Ethyl brom5 2ethoxide Sodium5 2(a) Order of reactivity of primary halide isX CH CH CH X CH CH X CH2 2 3 2 3 3. (b) Tendency of alkyl halide to undergo elimination is o o o1 2 3 . (c) For better yield alkyl halide should be primary and alkoxide should be secondary or tertiary. ether butyl. Ethyl tert333||5 2alcohol butyltert.of salt Sodium333||ide Ethyl brom5 2CHCHCH C O H CCHCHCH C NaO Br H COCH3 Methoxy benzene CH2OH Benzyl alcohol OCH3 Anisole (d)Secondaryandtertiaryalkylhalidesreadilyundergo2Eeliminationinthepresenceofastrongbasetoform alkenes. 33||333||35 2CHCHCl C CHCHCH Cl C CHONa H C, 325 2|| |3325 2||3CHCHOH H C C CHCHH CHO H C C CH2SNmechanism :ONa H C5 2 Na O H C5 2,I H OC H C I H C O H C I H C O H C5 2 5 2Faststate Trnsition5 2 5 2slow5 2 5 2- - - - - - - - ,I Na NaINote : Aryl halide and sodium alkoxide cannot be used for preparing phenolic ethers because aryl halide are less reactive toward nucleophilic substitution reaction than alkyl halides. (ii) By heating alkyl halide with dry silver oxide AgX R O R O Ag RX 2 2heat2,AgBr H OC H C O Ag Br H C 2 2ether Diethyl 5 2 5 2heat2ide Ethyl brom5 2 (2) From alcohols (i) By dehydration of alcohols (a) With conc. H2SO4 at 140 C :O H ROR HOR ROHCSO Ho2Ether 140) conc. (alcohol of molecules 24 2.Note : In this reaction alcohol must be present in excess. This reaction is mainly applicable for the dehydration of primary alcohols. Secondary and tertiary alcohols form alkenes mainly. When this reaction is carried out between different alcohols then there is a mixture of different ethers is obtained. Example :5 2 5 2 3 3 5 2 3140) conc. (Ethanol5 2Methanol34 2H C O H C CH O CH H C O CH OH H C OH CHCSO Ho (b) With Al2O3 at 250 C :O H R O R ROHCO Alo22503 22(ii) By the action of diazomethane on alcohols : This reaction is in presence of catalyst, boron trifluoride or 4HBF . 2 3 2 23N CH O R N CH ROHBF (iii) Addition of alcohols to alkenes : Ether2 3Alcohol2 24 2OR CH CH HOR CH CHSO H. The intermediate is carbonium ion. H CH CH2 2 2 3H C CH ,RHO CH CH HOR H C CH|2 3 2 3, Ether2 3|2 3R O CH CH RHO CH CHH. (a) This method is very useful for preparing mixed ethers. (b) In higher cases, there can be 1, 2-hydride or 1, 2-methyl shift to form more stable carbonium ion. (3) Alkoxy mercuration-demercuration Ether||||3||||acetate rifluoro Mercuric t2 3alkene4] [H OR C CHgOOCCFCORC OOCCF Hg OH R C CNaBH Note : This is the best method for the preparation of t-ethers. (4) Reaction of lower halogenated ether with grignard reagent2etherHigher 2reagantGrignardetherd Halogenate2MgX R ROCH R XMg X ROCH (i) Higher members can be prepared by the action of grignard reagent on lower halogenated ethers. (ii) Ether form soluble coordinated complexes with grignard reagent. General properties of ethers.Physical properties (1) Physical state : Methoxymethaneandmethoxyethanearegaseswhileothermembersarevolatileliquid with pleasant smell. (2) Dipole moment (D.M.) : Bond angle of ether is due to 3sphybridisation of oxygen atom. Since C O bond is a polar bond, hence ether possess a net dipole moment, even if they are symmetrical. D.M. of dimethyl ether is 1.3 D D.M. of di ethyl ether is 1.18 D Note :Thelargerbondanglemaybebecauseofgreaterrepulsiveinteractionbetweenbulkieralkylgroupsas compared to smaller H-atoms in water. (3) Boiling points : Boiling points of ethers are much lower than those of isomeric alcohols, but closer to alkanes having comparable mass. This is due to the absence of hydrogen bonding in ethers. (4) Solubility : Solubilities of ethers in water are comparable with those of alcohols. Example : Di ethyl ether and n-butyl alcohol have approximately the same solubility in water. This is because, ether form hydrogen bond with water much in the same way as alcohol do with water. EtherWaterEther. ....................RRO HO H ORR Note : Solubility of ether in water decreases with the size of alkyl groups. (5) Hydrogen bonding : Thereisnohydrogendirectlyattach(bonded)tooxygeninethers,soethersdonot show any intermolecular hydrogen bonding. alcohols in ndinghydrogenbo| | |- - - - - - - - -RO HRO HRO Hether in bond hydrogen NoR O R(6) Density : Ethers are lighter than water. Chemical properties :Ethers are quite stable compounds. These are not easily attacked by alkalies, dilute mineral acids, active metals, reducing agents or oxidising agents under ordinary conditions. (1) Reaction due to alkyl group (i) Halogenation : ) ether diethylMonochloro - (3 2 3darkether Diethyl 3 2 2 32CH CHClOCH CH CH OCH CH CHCl ) ether ethylDichlorodi - , (3 3darkether Diethyl 3 2 2 32H CHClOCHClC CH CH OCH CH CHCl HCl Cl OC Cl C Cl H OC H CCl10 10) ether iethylPerchlorod (5 2 5 2light2 5 2 5 22 (ii) Burning : Ethers are highly inflammable. They burn like alkanes.O H CO O H C O H C2 2 2 5 2 5 25 4 6(2) Reaction due to ethernal oxygen (i) Peroxide formation : 5 2 5 2 5 2 5 2:. .. .:. .:. .. .. .. .H COO H C O H C O H CorO O H C2 5 2) ( . (a) The boiling point of peroxide is higher than that of ether. It is left as residue in the distillation of ether and may cause explosion. Therefore ether may never be evaporated to dryness. (b) Absolute ether can be prepared by distillation of ordinary ether from conc.4 2SO Hand subsequent storing over metallic sodium.Note : Formation of peroxide can be prevented by adding small amount ofO Cu2 to ether. With strong oxidising agent like acid, dichromate ethers are oxidised to aldehydes. O H CHO CH CH OCH CH CHO2de Acetaldehy3] [ 23 2 2 32The presence of peroxide can be indicated by the formation of blood red colour complex in the following reaction. ) 6 to 1 ( colour red Blood3 3 2] ) ( [ PeroxidennnSCNSCN Fe Fe Fe (ii) Oxidation with K2Cr2O7 / H: RRCH O CH R2 (a) Oxidation of ether can only be possible if any one of the alkyl groups of ether has hydrogen on-carbon. (b)-carbon having two hydrogens converts in carboxylic group and-carbonhaving only one hydrogen converts into keto group. COOH CH CH COOH CH CH CH CH O CH CHHO Cr K2 3 3/3 2 2 2 37 2 2 3| |3 3/332 37 2 2CHOC CH COOH CHCHCHCH O CH CHHO Cr K (iii)Saltformation:Duetolonepairofelectronsonoxygenatom.EtherbehavesasLewisbaseandformstable oxonium salt with strong inorganic acids at low temperature. chloride oxonium Diethyl |2 5 2 5 2 5 2. .) ( ClHO H C HCl H OC H CorCl H O H C ] ) [(2 5 2 sulphate hydrogen oxonium Diethyl 4|2 5 2 4 2 5 2 5 2. .) ( HSOHO H C SO H H OC H C or 4 2 5 2] ) [( HSO H O H CThe oxonium salts are soluble in acid solution and ethers can be recovered from the oxonium salts by treatment with water.HCl O H C ClHO H CO Hether Diethyl 2 5 2salt Oxonium|2 5 2) ( ) (2 Note : The formation of oxonium salt is similar to the formation of ammonium salts from ammonia and acids. Ether is removed from alkyl halides by shaking with conc.4 2SO H . Ethers can be distinguished from alkanes with the help of this reaction. (iv) Reaction with Lewis acids : Being Lewis bases, ethers form complexes with Lewis acids such as 3BF , 3AlCl , 3FeCl , etc. These complexes are called etherates. (complex) etherate de trifluori Boron32 32 332 32 3. .:. .BF OCH CH CH CHBF OCH CH CH CH Similarly, diethyl ether reacts with Grignard reagent forming Grignard reagent etherate. etherate reagent Grignard2 3 22 2 32 2 3) () () ( 2XCH CH OMgO CH CHRRMgX O CH CH Due to the formation of the etherate, Grignard reagents dissolve in ether. That is why Grignard reagents are usually prepared in ethers. However, they cannot be prepared in benzene, because benzene has no lone pair of electrons and therefore, cannot form complexes with them.(3) Reaction involving cleavage of carbon-oxygen bond (i) Hydrolysis (a) With dil.4 2SO H: ROH O H RORSO H24 22 Ethanol5 2 2ether Diethyl 5 2 5 224 2OH H C O H H OC H CSO H (b) With conc.4 2SO H: O H HSO H C SO H H OC H CO H HSO H C SO H OH H CHSO H C OH H C SO H H OC H C2sulphate hydrogen Ethyl 4 5 2 4 2ether Diethyl 5 2 5 22 4 5 2 4 2 5 24 5 2 5 2 4 2 5 2 5 22 2 (ii) Action of hydroiodic acid (a) With cold HI : alcohol Ethyl 5 2iodide Ethyl 5 2Coldether Diethyl 5 2 5 2OH H C I H C HI H OC H C Note : Same reaction are observed with HBr and HCl. The order of reactivity of halogen acid HI>HBr>HCl. Mechanism of the reaction OC2H5 Phenyl ethyl ether +HBr OH Phenol +C2H5Br Ethyl bromide e Nucleophilether Protonated| Ether. .X RHO R X H R O R , Alcohol halide Alkyl. .OH R X RHRO R XThis can be explained on the basis of steric hinderence. The above reaction is aN Sreaction. The ether molecule gets protonated by the hydrogen of the acid to form protonated ether and the protonated ether undergoes nucleophilic attack by halide ion] [Xand form alkyl alcohol and alkyl halide. (b) With hot HI :O H I R RI HI R O R2heat2(iii) Zeisel method :3 3) alc. ( RNO AgI AgNO RINote : The silver iodide thus form can be detected and estimated. This formed the basis of Zeisel method for the detection and estimation of alkoxy group in a compound. (iv) Action of PCl5 : 3heat52 POCl RCl PCl R O R . There is no reaction in cold. (v) Reaction with acetyl chloride : acetate Ethyl 5 2 3heatether Diethyl 5 2 5 2chloride Acetyl 32H COOC CH H C O H C COCl CHZnCl (vi) Reaction with acid anhydride : acetate Ethyl 5 2 3heatether Diethyl 5 2 5 2anhydride Acetic 3 322H COOC CH H C O H C OCCH O CO CHZnCl (vii) Dehydration :O H CH CH H OC H CCO Alo2 2 23005 2 5 223 2 (viii) Reaction with carbon mono oxide : ionate Ethyl prop5 2 5 2atm. 500150 /ether Diethyl 5 2 5 23H COOC H C CO H OC H CC BFo (ix) Action of bases : 5 2 2 2 4 3 2 2 2 3H C O i L CH CH CH CH CH O CH CH H H C i L (4) Ring substitution in aromatic ethers : Alkoxy group is ortho and para directing and it directs the incoming groups to ortho and para position. It activates the aromatic ring towards electrophilic substitution reaction. III, Iv and V show high electron density at ortho and para position. (i) Halogenation : Phenyl alkyl ethers undergo usual halogenation in benzene ring. Forexample,Brominationofanisolegivesorthoandparabromoderivativeevenintheabsenceofiron (III) bromide catalyst. OCH3 Br p-Bromoanisole OCH3 Br o-Bromoanisole OCH3 Anisole 22CSBr + .. :OR I .. :O R II .. +OR .. IIIIV .. +OR .. : .. +OR V Para isomer is obtained in 90% yield. (ii) Friedel craft reaction ; (iii) Nitration : Note : Ethers are relatively less reactive than phenol towards electrophilic substitution reaction. Some commercially important compounds of ethers.(1) Di methyl ether : It is the simplest ether. (i) Preparation (a) It can be prepared by using any of the general method of preparation. (b)O H CH O CH OH CHatm Co o2 3 315 , 400 350Alumina ,32(c) It can be manufactured by dehydration of methyl alcohol with conc.4 2SO HatCo140 . (ii) Properties (a) It is colourless highly inflammable gas having B.P. ofCo8 . 24 . (b)Itissolubleinwater,alcoholsandotherorganicsolventsandgivesallthecharacteristicreactionsof ethers. (iii) Uses (a) It is used in the form of compressed liquid as a refrigerant, low temperature solvent and propellant for sprays. (b) It is used for storing food stuffs by freezing on direct contact because it doe not leave any undesirable taste or smell. (2) Diethyl ether (Sulphuric ether) :It is the most important member of the ether series and is known as ether. It may also be regarded as an anhydride ofOH H C5 2(ethanol). (i) Preparation : Laboratory method : O H HSO H C SO H OH H C2 4 5 2heat4 2 5 2 4 2ether Diethyl 5 2 5 2[Excess]5 2 4 5 2SO H H OC H C OH H C HSO H COCH3 Anisole +3chloride Methyl 3AlClCl CHOCH3 CH3 Para OCH3 CH3 Ortho + OCH3 Anisole +33AlClCOCl CHOCH3 COCH3 p Methoxy acetophenone OCH3 COCH3 o-Methoxy acetophenone + OCH3 Methyl phenyl ether(Anisole) 4 2 3/ SO H HNO+ OCH3 NO3 Methyl-2nitrophenyl ether (o-Nitroanisole) OCH3 NO3 Methyl-4nitrophenyl ether (p-Nitroanisole) It is also known as Williamsons etheral continuous process. (ii) Properties (a) It is a colourless, highly volatile and inflammable liquid having boiling pointCo5 . 34 . (b) It has a pleasant smell and burning taste. (c) It is only slightly soluble in water but readily soluble in organic solvents. (d) Di ethyl ether is itself a very good solvent even for fats and oils. (e) It produces unconsciousness when inhaled.(iii) Uses (a) It is used as a refrigerant. (b) It is used as a reaction medium in 4LiAlHreduction and grignard synthesis. (c) It is used as an extracting solvent in laboratory. (d) Mixture of alcohol and ether is used as petrol substitute under the trade name Natalite. (e) It is used in perfumary and in the manufacture of smokeless powder. (3) Di-isopropyl ether (i) Preparation : 2 3 2 3125 757 32 2 3) ( ) ( 2 CH CHOCH CH O H CH CH CHCatmHo (ii) Properties : It is a colourless liquid with a pear like odour having B.P.Co5 . 68 . (iii) Uses : It is used for reducing knocking of petrol. (4) Divinyl ether (i) Preparation :O H KCl CH CH O CH CH KOH ClCH OCH ClCH CH2 2 2 2 2 2 22 2 (ii) Properties (a) It is highly inflammable liquid. (b) It is colourless and boils atCo3 . 28 . (iii) Uses : It is better anaesthetic than di ethyl ether because of its rapid action and rapidrecovery from anaesthesia. (5) Epoxides [oxirane] or cyclic ether OC C| | (i) Preparation (a) By oxidation of ethylene with oxygen : OCH CH O CH CHCAgo2 22502 2 22 2 (b) By oxidation of ethylene with peroxy acids : OR CH CH R CHR RCHH CO CFH CO H C3 33 5 6or . (c) By treatment of ethylene chlorohydrin with NaOH OCH CH OH CH ClCH CH CHNaOH HOCl2 2in chlorohydr Ethylene2 2 2 2(ii) Properties (a) It is a poisonous, flammable gas. (b) Its B.P. isCo14 . (c) It is very reactive compound because of its strained configuration. (d) An epoxide is converted into protonated epoxide by acid which can undergo attack by any nucleophilic reagent. OC C| | HOHCOHCHOC CHOHGlycol||||) epoxide Protonated (|| | Some of the chemical reactions (a)CaseI:Basecatalysedringopening:Inthiscasenucleophileattackonlesshinderedcarbonofthe oxirane ring and reaction is 2SNmechanism. 3||/3 3OCHR CHOHCRRRO CH CRROH CH Na O CH. (b)CaseII:Acidcatalysedringopening:Nucleophileattacksoncarbonof oxiraneringwhichishighly substituted. 2SNreaction is there. ROCHOHCH CRRRO CH CRRH OH CH3||/3 Some reactions of oxirane are given below Uses (a) It is used in the manufacture of ethylene glycol. H+ R CH2 CH2 OH Alcohol +(i) RMgX (ii) HOH R CH2 CH2 OH (i) R2CuLi (ii) HOH CH3 CH2 OH Ethanol + (i) LiAlH4 (ii) HOH/H CH2OH CH2NH2 2-Amino ethanol NH3CH2OH CH2X Ethylene halohydrin HX CH2 CH2OH | OCH3 2-Methoxy ethanol

CH3OH/H OCH3 | CH2 CH2OH 2-Methoxy ethanol CH3ONa CH3OH CH2 CH2 O (Ethylene oxide) (b) It is used in the manufacture of dacron. (c) It is used in the manufacture of solvent ethoxy ethanol used in varnishes and enamels for quick drying. (6) Crown ethers : The crown ethers are heterocyclic poly-ethers usually with at least four oxygen atoms. These are called crown ethers because they have crown like shape. 18-crown-6 means compound is eighteen member ring compound out of which [18 6 = 12] 12 atoms are carbon [i.e. six ethylene group 2 2CH CH ] and six atoms of oxygen. Crown ethers have remarkable affinity for metal ions. Example : 12-crown-4 has affinity withLiand 18-crown-6 has affinity withK . Example : yield % 1002benzene6 - crown - 182KX CN CH R X CH R N C K

Cl K F CH H C F K Cl CH H C yield 100%2 5 6le acetonitri6 - crown - 182 5 6 A crown ether binds certain metal ions depending on the size of the cavity. Inthisreaction,thecrownetheristhehostandthespeciesitbindsistheguest.Thecrown-guestcomplexis called an inclusion compound. (7) Anisole (Methyl phenyl ether) C6H5OCH3 or (methoxy benzene) (i) Preparation (a) By the action of methyl iodide on sodium phenoxide. NaI OCH H C ICH ONa H C3 5 6 3 5 6 (b) By passing vapours of phenol and methyl alcohol over heated thoria. O H OCH H C OH CH OH H CThO2 3 5 6 3 5 62 (c) By methylation of phenol with diazomethane. 2 3 5 6 2 2 5 6N OCH H C N CH OH H C(ii)Properties : It is a pleasant smelling liquid. It is used as a solvent in some organic reactions. Anisole undergoes electrophilic substitution reactions. 3OCHgroup is o- and p- directing. O O O OO O 18-crown-612-crown-6 OO OO + Na+ O .. .. O O OO Host O .. O O OO Na+ Inclusion compound Anisole is decomposed by conc. hydroiodic acid again into phenol. OCH3 +E+ OCH3 E + OCH3 E +H+ OCH3 +HI OH +CH3I heat