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Carboxylic Acids Carboxylic acids are the compounds containing
the carboxyl functional group
OH O
The carboxyl group is made up of carbonyl (>C=O) and hydroxyl (–OH) group.
Classification
(1) Carboxylic acids are classified as monocarboxylic acids, dicarboxylic acids, tricarboxylic acids etc. depending on the number of – COOH groups present in the molecule.
Tricarboxylicacid
2
|
|^2
Dicarboxy licacid
2
|^2
Monocarboxy licacid
3
CH COOH
CHCOOH
CHCOOH
CHCOOH
CHCOOH CHCOOH
(2) Monocarboxylic acids of aliphatic series are commonly known as fatty acids such as palmitic acid ( C 15 H 31 COOH )^ and stearic acid^ C (^) 17 H 35 COOH . (3) The general formula for monocarboxylic acids is (^) C (^) nH 2 n 1 COOH or CnH 2 nO 2. Where n = number of carbon atoms. (4) The carboxylic acids may be aliphatic or aromatic depending upon whether – COOH group is attached to aliphatic alkyl chain or aryl group respectively.
Methods of preparation of monocarboxylic acid
(1) By oxidation of alcohols, aldehydes and ketones
Carboxylicacid
[ } [] alcohol^2
RCH OH K CrO ^ O RCHO K CrO O RCOOH
monocarboxy licacid
[] RCHO Aldehy de (^) RCOOH O Aldehyde can be oxidized to carboxylic acid with mild oxidising agents such as ammonical silver nitrate solution[ Ag 2 O or Ag ( NH 3 ) 2 ^ OH ] Methanoic acid can not be prepared by oxidation method. Ketones can be oxidized under drastic conditions using strong oxidising agent like (^) K 2 Cr 2 O 7. Methyl ketones can also be converted to carboxylic acid through the haloform reaction_. R_ – (^) OC | | CH 3 3 I 2 3 NaOH H 2 O
OH CHI NaI H O O
R C | | 3 3 32
(2) By Hydrolysis of nitriles, ester, anhydrides and acid chloride (i) Hydrolysis of nitriles ^
^ Rearrangement or NH
R C N HOH R C OH
NaOH
HCl
R C NHO HHClO RCOOH NH 4 Cl 2
^2 ^ (ii) Hydrolysis of Esters RCOOR Ester ' HOH OH RCOOH Acid Alcohol R ' OH HCl (^) ^ (iii) Hydrolysis of Anhydrides
Carboxylic acids and Their derivatives
Chapter
Ethanoic^3 acid
/
Ethanoicanhydride
(^3) ||
|| (^3) O HOH 2 CHCOOH
O
CH C
O CH C H (^) OH
(iv) Hydrolysis of acid chloride and nitro alkane Cl HOH RCOOH HCl O
R C || H^ / OH
R CH 2 NO 2 ^85 % H ^^2 SO ^4 RCOOH (v) Hydrolysis of Trihalogen :
^ HO OH
OH
OH NaOH R C X
X
X R C 3 2
R C OHO 3 NaX (3) From Grignard Reagent
OMgX
O
O C O RMgX ^ R C Dryether ||
H ^ /^ H ^2 ^ O RCOOH Mg ( OH ) X (4) From Alkene or Hydro-carboxy-addition (koch reaction) CH CH CO HO CHCHCOOH C atm
H PO 3 2 &^500350
2 2 2 3 4 (^)
(5) Special methods (i) Carboxylation of sodium alkoxide RONa Sod. alkoxide CO RCOONa Sod.salt RCOOH Acid HCl (ii) Action of heat on dicarboxylic acid
Substitutedmalonicacid heat Monocarbox^2 ylicacid
(^2) R CHCOOH COOH R CH COOH CO ^
(iii) From acetoacetic ester
RCHCOOH CHOH
CHCOOH OHH OHH
CHCO CHRCO OCH 2 2 5
3 2 5 Hydrolysis^3 (iv) Oxidation of alkene and alkyne RCH CHR RCOOH RCOOH KMnO
O ^
Hot alkaline 4
[] Alkene
R C Alkyne C R ( ii ( i ) H^ ) O (^23) O R COOH R COOH (v) The Arndt-Eistert synthesis AgO CHN HO O
Cl CH N R C O
R C || 2 2 || 2 ^22
R CH 2 COOH
(vi) From acid amides RCONH Amide (^) 2 H 2 O orAcid Alkali RCOOH Acid NH 3 RCONH HNO RCOOH N 2 H 2 O Amide 2 Nitrous acid^2
Physical properties of monocarboxylic acids
(1) Physical state : The first three members (upto 3 carbon atoms) are colourless, pungent smelling liquids. The next six members are oily liquids having unpleasant smell. The higher members are colourless and odourless waxy solids. (2) Solubility : The lower members of the aliphatic carboxylic acid family (upto C 4 ) are highly soluble in water. The solubility decreases with the increase in the size of the alkyl group. All carboxylic acids are soluble in alcohol, ether and benzene etc. The solubility of lower members of carboxylic acids is due to the formation of hydrogen bonds between the – COOH group and water molecules. Acetic acid exists in the solution in dimer form due to intermolecular hydrogen bonding. The observed molecular mass of acetic acid is 120 instead of 60. (3) Melting point (i) The melting points of carboxylic acids donot vary smoothly from one member to another. (ii) The melting point of the acids having even number of carbon atoms are higher than those containing an odd number immediately above and below them. (iii) The acids with even number of carbon atoms have the – COOH group and the terminal – CH 3 group on the opposite side of the carbon chain. (iv) In the case of odd numbers, the two groups lie on the same side of the chain.
When the terminal groups lie on the opposite sides the molecules fit into each other more closely. More effective packing of the molecule in the lattice. Therefore, results into higher melting point. (4) Boiling point : Boiling point of carboxylic acids increase regularly with increase of molecular
Carbon dioxide^ Grignard reagent
CH 2
CH 3
COOH
CH 2
the two terminal groups lie on the opposite sides of the chain
CH 2
CH 3 CH 2 COOH
the two terminal groups lie on the same side of the chain
CH 2
effervescence. Therefore, this reaction may be used to distinguish between carboxylic acids and phenols. (2) Reaction involving replacement of – OH group (i) Formation of acid chloride CH Acetic (^) 3 COOH acid PCl 5 (^3) Acetyl CH (^3) chloride COCl POCl 3 HCl 3 CH Acetic (^) 3 COOH acid PCl 3 (^3) Acetyl CH (^3) chloride COCl H 3 PO 3 CH COOH SOCl CHCOCl SO 2 HCl Acetic^3 acid^2 Acetyl^3 chloride (ii) Formation of esters ( Esterification ) Acetic^3 acid Ethyl alcohol^25
CH CO OH H OCH CH COOCH H 2 O (FruityEthylacetate^ smelling)
(a) The reaction is shifted to the right by using excess of alcohol or removal of water by distillation. (b) The reactivity of alcohol towards esterification. tert - alcohol < sec- alcohol < pri - alcohol < methyl alcohol (c) The acidic strength of carboxylic acid plays only a minor role. R (^) 3 CCOOH R 2 CHCOOH RCH 2 COOH CH 3 COOH HCOOH When methanol is taken in place of ethanol. then reaction is called trans esterification. (iv) Formation of amides Amm.^3 acetate^4 3 heat Acetic^3 acid
CHCOOH NH CHCOONH
CH CONH H 2 O
Acetamide^3
(v) Formation of acid anhydrides
Aceticanhydride
Heat 33 2 3 Acetic^3 acid^25
CHCHCOCO O H^ O
CHCOOH CH CO OH P O ^ ^ (vi) Reaction with organo-metallic reagents R ' CH 2 MgBr RCOOH ether R Alkane' CH 3 RCOOMgBr (3) Reaction involving carbonyl (> C = O ) group: Reduction : OH R CH OH O
R C || LiAlH ^^4 2
Carboxylic acid are difficult to reduce either by catalytic hydrogenation or Na C 2 H 5 OH
(4) Reaction involving attack of carboxylic group (– COOH )
(i) Decarboxylation : OH R H
O
R C ( CO^ ^ )
| | 2
When anhydrous alkali salt of fatty acid is heated with sodalime then : RCOONa Sodium salt NaOH heat CaO ^ R Alkane H Na 2 CO 3 When sodium formate is heated with sodalim e H 2 is evolved_._ (Exception) HCOONa NaOH CaO ^ H 2 Na 2 CO 3 (ii) Heating of calcium salts ( RCOO Sodium )salt 2 Ca heat RCOR Ketone CaCO 3 (iii) Electrolysis : (Kolbe's synthesis) RCOONa ⇌ RCOO ^ Na At anode 2 RCOO ^ R R 2 CO 2 2 e At cathode 2 Na 2 e 2 Na ^2 H 2^ ^ O 2 NaOH H 2
Potassium^2 CH^3 COOK acetate^2 H^2 O Electrolys^ is CH Ethane (^) 3 CH 3 2 CO 2 2 KOH H 2 (iv) Formation of Alkyl halide (Hunsdiecker's reaction) CH Silver (^) 3 COOAg acetate Br 2 CCl heat 4 Methyl bro CH 3 Br mide AgBr CO 2 In Hunsdiecker reaction, one carbon atom less alkyl halide is formed from acid salt. (v) Formation of amines (Schmidt reaction) 2 2 aminePrimary
( .) 2 acidHydrazoic
RCOOH Acid N 3 H H^^2 SO ^4 conc RNH CO N
In Schmidt reaction, one carbon less product is formed. (vi) Complete reduction CH Acetic (^) 3 COOH acid 6 HI P^ CH Ethane 3 CH 3 2 H 2 O 3 I 2 In the above reaction, the – COOH group is reduced to a CH 3 group. (5) Reaction involving hydrogen of - carbon Halogenation (i) In presence of U.V. light
COOH HCl
Cl COOH Cl C
H C UV
| |
| 2 .. (^) |
(ii) In presence of Red P and diffused light [Hell Volhard-zelinsky reaction] Carboxylic acid having an -hydrogen react with Cl 2 or Br 2 in the presence of a small amount of red phosphorus to give chloro acetic acid. The reaction is known as Hell Volhard-zelinsky reaction.
Conc .H 2 SO 4
HCl
Cl P HCl CH COOH Cl^ P ClCHCOOH (^) 2 4 2 ,red 4 Chloro acetic^2 acid
,red Acetic^3 acid Trichloro^3 aceticacid
,red Dichloro^2 aceticacid Cl CHCOOH^2 4 ClCCOOH HCl
Cl P
Individual members of monocarboxylic acids
Formic Acid or Methanoic acid ( HCOOH ) Formic acid is the first member of monocarboxylic acids series. It occurs in the sting of bees, wasps, red ants, stinging nettles. and fruits. In traces it is present in perspiration, urine, blood and in caterpillar's. (1) Methods of preparation (i) Oxidation of methyl alcohol or formaldehyde CH (^) 3 OH O 2 HCOOH Formic acid H 2 O Pt^ (ii) Hydrolysis of hydrocyanic acid : Formic acid is formed by the hydrolysis of HCN with acids or alkalies. HCN 2 H 2 O HCl ^ HCOOH NH 3 ; HCN H 2 O NaOH ^ HCOONa NH 3 (iii) Laboratory preparation
C
CO C
HO
CHOOCCOO H
CHOH
CHOH
CHOH HOOCCOOH
CHOH
C HOH ^ o (^)
110 monoxalateGlycerol
2
2
| 100120 |
Oxalicacid
Glycerol
2
2
| |
2 2
Glycerol
2
2
| Formicacid |
( ) 2
monoformatGlycerol e
2
2
| |
2 2
CH OH
CHOH
HCOOH CHOH
CHOOCH
CHOH
CHOH COOH ^ H O
The following procedure is applied for obtaining anhydrous formic acid. 2 HCOOH PbCO 3 ( HCOO Lead formate) 2 Pb CO 2 H 2 O ; ( HCOO ) 2 Pb H 2 S PbS ppt. (^2) Formic HCOOH acid (iv) Industrial preparation : Formic acid is prepared on industrial scale by heating sodium hydroxide with carbon monoxide at 210° C under a pressure of about 10 atmospheres. CO NaOH 210 o (^) C (^) , 10 atmSodium HCOONa formate
Sodium formate thus formed is distilled with sodium hydrogen sulphate, when anhydrous formic acid distils over. HCOONa NaHSO 4 HCOOH Na 2 SO 4 (2) Physical properties (i) It is a colourless pungent smelling liquid.
(ii) It melts at 8.4° C and boils at 100.5° C. (iii) It is miscible with water, alcohol and ether. It forms azeotropic mixture with water. (iv) It is strongly corrosive and cause blisters on skin. (v) It exists in aqueous solution as a dimer involving hydrogen bonding. (3) Uses : Formic acid is used. (i) In the laboratory for preparation of carbon monoxide. (ii) In the preservation of fruits. (iii) In textile dyeing and finishing. (iv) In leather tanning. (v) As coagulating agent for rubber latex. (vi) As an antiseptic and in the treatment of gout. (vii) In the manufacture of plastics, water proofing compounds. (viii) In electroplating to give proper deposit of metals. (ix) In the preparation of nickel formate which is used as a catalyst in the hydrogenation of oils. (x) As a reducing agent. (xi) In the manufacture of oxalic acid. Acetic Acid (Ethanoic Acid) ( CH 3 COOH ) Acetic acid is the oldest known fatty acid. It is the chief constituent of vinegar and hence its name (Latin acetum = vinegar) (1) Preparation (i) By oxidation of acetaldehyde (Laboratory- preparation) CH (^) 3 CHO HNa 2 SO^2 Cr^42 O ( O ^7 ) CH 3 COOH (ii) By hydrolysis of methyl cyanide with acid CH 3 (^) CN 2 H 2 O HCl ^ CH 3 COOH NH 3 (iii) By Grignard reagent
OMgBr H O^ H
O
CH MgBr CO CH C^2
| | 3 2 3
OH
O CH C
| | 3
(iv) By hydrolysis of acetyl chloride, acetic anhydride or acetamide and ester (a) 2 (conc.) (^3) Ester 2 5 CHCOOCH H O H^2 SO^4 CH (^) 3 COOH C 2 H 5 OH
HCOOH Na HCOONa 21 H 2 CH (^) 3 COOH Na CH 3 COONa 21 H 2
(ii) With bases Forms salts. HCOOH NaOH HCOONa H 2 O
Forms salts. CH (^) 3 COOH NaOH CH 3 COONa H 2 O (iii) With carbonates and bicarbonates
Forms salts. Carbon dioxide is evolved. HCOOH NaHCO 3 HCOONa H 2 O CO 2
Forms salts. Carbon dioxide is evolved. CH 3 COOH NaHCO 3 CH (^) 3 COONa H 2 O CO 2
- Ester formation Forms esters when treated with alcohols. HCOOH C 2 H 5 OH HCOOC 2 H 5 H 2 O
Forms esters when treated with alcohols. CH 3 COOH C 2 H 5 OH H^2 SO ^4 ( conc .) CH (^) 3 COOC 2 H 5 H 2 O
- Reaction with PCl 5 Forms formyl chloride which decomposes into CO and HCl. HCOOH PCl 5 HCOCl ( HCl CO ) POCl 3 HCl
Forms acetyl chloride which is a stable compound. CH 3 COOH PCl 5 CH (^) 3 COCl POCl 3 HCl
- Heating of ammonium salt
Forms formamide. HCOONH (^) 4 HCONH 2 H 2 O
Forms acetamide. CH (^) 3 COONH 4 CH 3 CONH 2 H 2 O
- Heating alone it decomposes into CO 2 and H 2 HCOOH CO 2 H 2
Unaffected
- Heating with conc. H 2 SO 4
Decomposed into CO and H 2 O HCOOH (^) HConcSO^. CO H 2 O 2 4
Unaffected
- Reaction with Cl 2 in presence of red P
Unaffected Forms mono, di or trichloro acetic acids.
- Action of heat on salts, (i) Calcium salt
Forms formaldehyde. ( HCOO ) (^) 2 Ca HCHO CaCO 3
Forms acetone. ( CH 3 (^) COO ) 2 Ca CH 3 COCH 3 CaCO 3 (ii) Sodium salt Forms sodium oxalate.
2 heat^ | H 2 COONa COONa
HCOONa
Unaffected.
(iii) Sodium salt with soda-lime
Forms sodium carbonate and H 2. HCOONa NaOH CaO ^ Na 2 CO 3 H 2
Forms sodium carbonate and methane. CH 3 COONa NaOH CaO CH (^) 4 Na 2 CO 3
- Electrolysis of sodium or potassium salt
It evolves hydrogen. It forms ethane.
- On heating with P 2 O 5
Unaffected Forms acetic anhydride. 2 CH (^) 3 COOH P^2^ O^ ^5 ( CH 3 CO ) 2 O H 2 O
- Reducing nature, (i) Tollen's reagent Gives silver mirror or black precipitate. HCOOH Ag 2 O 2 Ag CO 2 H 2 O
Unaffected.
(ii) Fehling's solution Gives red precipitate HCOOH 2 CuO Cu 2 O CO 2 H 2 O
Unaffected.
(iii) Mercuric Forms a white ppt. which changes to Unaffected.
chloride greyish black. HgCl (^) 2 Hg 2 Cl 2 2 Hg (iv) Acidified KMnO 4 Decolourises Unaffected.
- Acid (neutral solution) + NaHSO 3 + Sodium nitroprusside.
Greenish blue colour. Unaffected.
- Acid (neutral solution) + neutral ferric chloride
Red colour which changes to brown ppt. on heating.
Wine red colour.
Interconversions (1) Ascent of series : Conversion of formic acid into acetic acid. (i) Formaldehyde
heat Calcium formate^2
( ) Formic acid ( ) HCOOH Ca^ OH ^2 HCOO Ca HCHO
Ethy l^3 alcohol^2 Additio^3 n^2 product
[] Acetaldehy^3 de CH CHO CHCHOH^2 CHCHOMgBr H
O HO (^)
Acetic^3 acid [ ^ O ] CHCOOH
(ii) iodideMethyl
Formaldehy HCHO^ de H^2^ ^ Ni Methyl CH^3 alcohol OH HI CH^3 I
cyanideMethyl
CH Acitic (^) 3 COOH acid HH ^2 O CH 3 CN
Arndt-Eistert homologation : This is a convenient method of converting an acid, RCOOH to RCH 2 COOH. RCOOH SOCl ^^2 RCOCl CH 2 N ^2 RCOCHN 2 RCH (^) 2 COOH Hy droly sis RCH 2 COOC 2 H 5
(2) Descent of series : Conversion of acetic acid into formic acid.
Methy l^3 amine^2 Methy l^3 alcohol
2 2 4
(^3) CH NH NaNO HCl CHOH HSO
N^ H
Formaldehyde
[] HCOOH Formic acid HCHO O
Methy l CH^3 NH amine 2
Acetamide^3
heat Acetic^3 acid Amm.^3 aceta te^4
CH COOH NH ^^3 CHCOONH CHCONH
chlorideMethy l
NaOH ^ CH Sodium (^) 3 COONa acetate Sodalime heat Methane CH 4 Clhv ^2 CH 3 Cl
Methy l^3 alcohol
[] Formaldehyde
[] HCOOH Formicacid HCHO HNa 22 SOCr 42 O 7 CH OH O^ O
Conversion of Acetic acid into other organic compound
CH r 3 MgB
KCN. ) ( Alc
EtOH Ag 2 O
[ O ]
AgOH
Br KOH 2 /
[O]
CH 3 CH= CH 2
Propene 500° C
Cl 2 ClCH 2 CH = CH 2 Allyl chloride
CH (^3) Ethane– CH (^3) [O] CH (^3) Acetic acid – COOH
Cl 2 hv
CH 3 – CH 2 Cl chloride^ Ethyl
AgOH (^) CH 3 – CH 2 OH Ethyl alcohol
CH 3 – CHO
Acetaldehyde
CH
COCl 3 Electrolys is
CH Ethyl amin 3 C H 2 NH (^2) e
CH 3 C H 2 CH 2 NH 2 n - Propyl amine
[ H ] LiAlH 4
CH 3 C H 2 CN H H^2 +O^ CH Propionic acid^3 CH^2 COOH
CH 3 COONa Sodium acetate
Sodali me CH 4 Methane chloride Methyl^ CH^3 Cl
AgOH (^) CH 3 OH alcohol^ Methyl
[ O ]
Cl 2 hv
HCOOH Formic acid
NaO H
HCOONa Sodium formate
COONa | heat COONa Sodium oxalate
COOH | H 2 SO 4
COOH
Oxalic acid CH 3 COOH Ca 2 ( OH ) ( Calcium acetate CH 3 COO ) 2 Ca^ hea t CH 3 COCH 3 Acetone
H Ni (^2) / CH 3 CHOHCH 3 Isopropyl alcohol
Conc. H 2 SO 4
I 2 + NaOH CHI 3
Iodofor m A
HC ≡ CH
acetylene
Acetic^ ( CH^3 CO )^2 O anhydride
NH 3 KCN
HCHO
Formaldehyde
[ O ]
NaOH
filtration. It is decomposed with calculated quantity of dilute sulphuric acid. COO Ca NaOH COO
COONa CaOH COONa
| ( ) | 2 Calcium oxalate
2
Calcium(insoluble sulphate) 4 Oxalic(soluble)acid
| 2 4 (dil.) | CaSO
COOH
COOH
COO Ca HSO COO
(2) Physical Properties (i) It is a colourless crystalline solid. It consists of two molecules of water as water of crystallisation. (ii) The hydrated form has the melting point 101.5° C while the anhydrous form melts at 190° C. (iii) It is soluble in water and alcohol but insoluble in ether. (iv) It is poisonous in nature. It affects the central nervous system. (3) Chemical Properties (i) Action of heat : It becomes anhydrous. COOH HO C COOH H 2 O oxalicAnhydrousacid
(^1001052) Hydratedacid oxalic
(a) At 200° C ,( COOH ) 2 HCOOH Formicacid CO 2 On further heating, formic acid also decomposes. HCOOH CO 2 H 2 (b) Heating with conc. H 2 SO 4 COOH CO CO HO COOH conc
HSO 2 2 ( .)
| ^2 ^4
(ii) Acidic nature Salt formation
Oxalicacid Acidpot.oxalate Pot.oxalate
| | |
COOK COOK
COOK COOK
KOH
COOH COOH
^ KOH
COONa CO HO COONa
COOH NaHCO COOH^3 Sod.oxalate^22
| 2 | 2 2
| 2 3 | H 2 O CO 2 COONa COONa
COOH NaCO COOH
(iii) Esterification
Ethyloxalate
2 5 2 5 Ethyloxalatehydrogen
| 2 5 |^2525 COOC |^ H
COOCH
COOCH
COOH
COOH
COOH
C^ H OH C H ^ OH
(iv) Reaction with PCl 5 :
COCl POCl HCl COCl
COOH PCl COOH
| 2 | 2 3 2 chlorideOxalyl
5
(v) Reaction with ammonia
Amm.oxalate
4 4 Acidoxalateammonium
4 | 3 |^3 |
COONH
COONH
COONH
COOH
COOH NH
COOH
^ NH
Oxamicacid
|^ CONH^2
COOH
Oxamide
2 2
CONH
CONH
(vi) Oxidation : When oxalic acid is warmed with acidified (^) KMnO 4. 2 KMnO 4 (^) 3 H 2 SO 4 K 2 SO 4 2 MnSO 4 3 H 2 O 5 [ O ]
KMnO HSO COOHCOOH KSO MnSO CO HO
COOHCOOH O CO HO 2 4 4 2 2 Oxalicacid
2 4 | Pot.(Purple) permanganate 4
| 2 2 2 3 5 2 10 8
[ ] 2 5
^
Oxalic acid decolourises the acidic KMnO 4 solution. (vii) Reaction with ethylene glycol
(viii) Reduction : HO
CHOH
COOH
COOH H
COOH HSO
Zn (^) 2 Glycolicacid
| 4 |^2
COOH HO
CHO
CHOH
COOH
COOH
COOH H^ Glycolicacid Glyoxalicacid^2
2 6 [ ] 2 | Electrolyt ic^ reduction | | 2
(ix) Reaction with Glycerol : At 100° – 110° C , formic acid is formed. At 260°, allyl alcohol is formed. (4) Uses : Oxalic acid (Polyprotic acid) is used, (i) In the manufacture of carbon monoxide, formic acid and allyl alcohol. (ii) As a laboratory reagent and as a standard substance in volumetric analysis. (iii) In the form of antimony salt as a mordant in dyeing and calico printing.
- H 2 O (^) heat^ – 2 H 2 O^ heat
O=C
O=C
CH 2
CH 2
O
O
Oxalic acid Ethylene glycol Ethylene oxalate
O=C
O=C
CH 2
CH 2
OH
OH
H O
H O
+ (^) – heat H 2 O
Colourless
(iv) In the manufacture of inks. (v) For removing ink stains and rust stains and for bleaching straw, wood and leather. (vi) In the form of ferrous potassium oxalate as developer in photography. (5) Analytical test (i) The aqueous solution turns blue litmus red. (ii) The aqueous solution evolves effervescences with NaHCO 3. (iii) The neutral solution gives a white precipitate with calcium chloride solution. It is insoluble in acetic acid.
Oxalic^2 2 acid^4 Amm.oxalat^422 e 4 Calcium 2 oxalate^4 H CO NH^ 4 OH ( NH ) CO CaCl ^2 CaCO (iv) Oxalic acid decolourises hot potassium permanganate solution having dilute sulphuric acid. (v) With hot conc. H 2 SO 4 , it evolves carbon monoxide which burns with blue flame. Malonic Acid or Propane-1,3-Dioic Acid COOH CH 2 COOH or CH 2 (COOH) 2 or (C 3 H 4 O 4 ) The acid occurs as calcium salt in sugar beet. It was so named because it was first obtained from malic acid (hydroxy succinic acid) by oxidation. (1) Methods of Preparation : From acetic acid CH Acetic 3 COOH acid Cl P^2^^ CH Chloroacet 2 ClCOOH icacid KCN ( Aq .)
Malonicacid
CH Cyano (^) 2 CNCOOH aceticacid H^2^ O H CH (^2) COOHCOOH
(2) Physical Properties (i) It is a white crystalline solid. (ii) It's melting point is 135° C. (iii) It is soluble in water and alcohol but sparingly soluble in ether. (3) Chemical Properties (i) Action of heat (a) Heating at 150°C : CH (^) 2 ( COOH ) 2 CH 3 COOH CO 2 (b) Heating with P 2 O 5 :
O O C C C O HO
OH
C
H
H
C
OH
O C P heat O Carbonsuboxide 2
| |
| | 2
^2 ^5
(ii) Reaction with aldehyde : With aldehydes, - unsaturated acids are formed.
heat 2 Pyridine Aldehyde^ COOH ^
RCH O H C COOH
RCH - unsaturate CHCOOH dacid H 2 O CO 2 (4) Uses : Its diethyl ester (malonic ester) is a valuable synthetic reagent for preparation of a variety of carboxylic acids. Succinic Acid or Butane-1,4-Dioic Acid : CH COOH CH COOH
2 2
| or (CH 2 ) 2 (COOH) 2 or (C 4 H 6 O 4 ) It was first obtained by the distillation of yellow fossil, resin, amber and hence its name (Latin, Succinum = amber). It is also formed in small amount during the fermentation of sugar. (1) Methods of Preparation (i) From ethylene
Succinic^2 acid
2 cy anideEthy lene
2 2 bromideEthy lene
2 Ethy lene^2
2 2 |
| |^2 | |^2
CH COOH
CHCOOH
CHCN
CHCN
CHBr CHBr
CH
CH
Br ^ NaCN HO ^ HCl
(ii) From maleic acid [catalytic reduction] CHCOOH CHCOOH
CHCOOH H
CHCOOH
Ni^2 heat 2
This is an industrial method. (iii) Reduction of tartaric acid or malic acid
Succinicacid Malic^2 acid
2 Tartaricacid^2
| | CHOHCOOH |
CH COOH
CHCOOH
CHCOOH
CHOHCOOH
CHOHCOOH P
HI P
HI ^
(2) Physical properties (i) It is a white crystalline solid. It melts at 188 oC (ii) It is less soluble in water. It is comparatively more soluble in alcohol. (3) Chemical Properties : Succinic acid gives the usual reactions of dicarboxylic acid, some important reactions are : (i) Action of heat : At 300° C O
CHCO CHCO
CHCOOH CH COOH HO
C Succinic anhy dride
2 (– ) 2
300 Succinicacid
2 2
| 2 |
(ii) With ammonia
HO
NH CHCOONH
CHCOONH
CHCOOH
CH COOH 2
3 heat Ammoniumsuccinate
2 4 2 4
2 2
NH
CHCO
CHCO
CHCONH
CH CONH NH
Succinimid e
2 2
heat Succinamide
2 2 2 2
(iii) Reaction with Br 2
(v) From vinyl cyanide Acetylene (^90) Vinyl^2 cyanide
HC CH HCN^2 2 CH CH CN
C Cu^ Cl HCl H^ H ^2 ^ O CH 2 CH COOH (vi) From ethylene cyanohydrin HO
HCN CH CN HSO
OH
CH
O
CH CH Conc. heat^224 Ethylenecyanohydrin
|^22 Ethyleneoxide
2 2 ^ ^ ^
CH CH CN H^ H O CH 2 CHCOOH (acrylonitVinylcyaniderile)
2 2
Industrial method : This is a new method of its manufacture. CH CH CO H 2 O Ni^ ( CO )^4 CH 2 CHCOOH (2) Physical Properties It is colourless pungent smelling liquid. Its boiling point is 141° C. It is miscible with water, alcohol and ether. It shows properties of an alkene as well as of an acid. (3) Chemical Properties (i) With nascent hydrogen (Na and C 2 H 5 OH) CH (^) 2 CHCOOH 2 [ H ] Ni ^ CH 3 CH 2 COOH (ii) With halogens and halogen acids : Markownikoff's rule is not followed. (^2 2) , - (^2) Dibromopropionicacid 4
CH CHCOOH Br CCl ^ CH Br CHBrCOOH
(^2) -Bromopropi 2 onic (^2) acid CH CHCOOH HBr BrCH CH COOH (iii) Oxidation : In presence of dilute alkaline KMnO 4. (^2 22) Glycericacid CH CHCOOH [ O ] H O CH OHCHOHCOOH On vigorous oxidation, oxalic acid is formed. (iv) Salt formation CH (^) 2 CHCOOH KOH CH 2 CHCOOK H 2 O 2 CH 2 CHCOOH Na 2 CO 3 (^2) Sodium CH (^) 2 acrylate CHCOONa H 2 O CO 2 (v) Ester formation HO
CH CHCOOH HOC H HSO
2 2 2 5 Conc.^24
(^2) Ethylacrylate 2 5 CH CH COOCH
(vi) With PCl 5 (^2 52) Acrylchloride CH CHCOOH PCl CH CH COCl (4) Uses : Its ester are used for making plastics such as Lucite and plexiglass.
Unsaturated dicarboxylic acids
The molecular formula of the simplest unsaturated dicarboxylic acid is HOOC. CH CH. COOH This formula, however represents two chemical compounds, maleic acid and fumaric acid, which are geometrical isomers.
|| Cis
H C COOH
H C COOH
|| Trans
H C COOH
HOOC C H
(1) Methods of Preparation of Maleic Acid (i) By catalytic oxidation of 2-butene or benzene CHCOOH H O CHCOOH
CH CH
CH CH C
V O 2 Maleicacid
(^2400) 2 Butene
3 3
| | 30 ^2 ^5 || 2
CHCOOH CHCOOH
CH CO O
CH CO
C H^92 O V^2 O o^5 C || H^2 OH || (^400) Maleic anhydride Benzene^6 62 ^
(ii) From malic acid :
Maleicanhydride
heat
(intermediMaleicacidate)
heat
(HydroxyMalic succinicacidacid)
2
| ( ) || | | 2 2
CH CO O CH CO
CHCOOH CHCOOH
CHOHCOOH CH COOH HO HO
Sodiumsalt Maleicacid
boil |^ | |^ |
2 CH^ COOH CH COOH
CH COONa CH COONa
NaOH H H O
(2) Methods of Preparation of Fumaric Acid (i) From maleic acid : HOOC CH HCCOOH
H CCOOH H CCOOH
HCl
| | boil | | Maleicacid (ii) By oxidation of furfural with sodium chlorate
O
CO
HOOCC H
H CCOOH
O
CH
CCHO
HC
HC
| | || 4 [ ]^ NaClO^^3 || 2
(iii) By heating malic acid at about 150°C for long time HOOC C H H C COOH
CHOHCOOH CH COOH C HO
(^) | |
( ) | 150 heat, 2 (^2) Malicacid (iv) By heating bromosuccinic acid with alcoholic potash : By heating bromosuccinic acid with alcoholic potash.
KBr H O
HOOC C H H C COOH
CHCOOH CH BrCOOH
(^2) Alc. KOH (^) | | 2 .( )
|
(3) Physical Properties (i) Both are colourless crystalline solids. Both are soluble in water. (ii) The melting point of maleic acid (130.5° C ) is lower than the melting point of fumaric acid (287° C ). (4) Chemical Properties Chemically, both the acids give the reactions of alkenes and dibasic acids except that the maleic acid on heating forms an anhydride while fumaric acid does not give anhydride. CHCO O HO CHCO
CHCOOH CHCOOH (^) Maleicanhydride^2
heat Maleicacid
| | | |
Both form succinic acid on reduction with sodium amalgam. They undergo addition reactions with bromine, hydrobromic acid, water, etc. and form salts, esters and acid chlorides as usual. With alkaline KMnO 4 solution, they get oxidised to tartaric acid.
(Racemicmixture)
|
|
(anti-addition)
water Maleic( acid) (Syn-addition)
Alk.
Tartaric(Meso)acid
|
|
| 4 ||^2 |
COOH H C Br
COOH
Br C H
H CCOOH H CCOOH
COOH H COH
COOH
H COH
Br
Cis
KMnO
((Meso)
| (anti-addition) |
water Fumaricacid( )
(Syn-addition)
Alk.
(RacemicTarta ricmixture)acid
|
|
| 4 ||^2 |
COOH H C Br
COOH
H C Br
H C COOH HOOCC H
COOH H COH
COOH
HO C H
Br Trans
KMnO
Higher fatty acids
Palmitic, stearic and oleic acids are found in natural fats and oils as glyceryl esters. They have derived their names from the natural source from which they are prepared by hydrolysis with alkali. Table : 28. Name of acids
Source Molecular formula Palmitic acid Palm oil CH (^) 3 ( CH 2 ) 14 COOH Stearic acid Stear (meaning tallow)
CH (^) 3 ( CH 2 ) 16 COOH
Oleic acid Olive oil. CH (^) 3 ( CH 2 ) 7 CH CH ( CH 2 ) 7 COOH
Palmitic and stearic acids are waxy colourless solids with melting points 64° C and 72° C , respectively. They are insoluble in water but soluble in ethanol and ether. They find use in the manufacture of soaps and candles. Soaps contain sodium or potassium salts of these higher fatty acids. Oleic acid has low melting point, i.e. , 16° C. It is insoluble in water but soluble in alcohol and ether. Besides the reactions of acids, it also gives reactions of alkenes. Two aldehydes are formed on ozonolysis. iiZnHO CH CH CH CHCH COOH iO 2
3 ( )
3 (^2 ) 7 ( 2 ) 7 ()
CH 3 ( CH 2 ) 7 CHO HOOC ( CH 2 ) 7 CHO
It is used for making soaps, lubricants and detergents. (1) Difference between oils and fats : Oils and fats belong to the same chemical group, yet they are different in their physical state. (i) Oils are liquids at ordinary temperature (below 20° C ) while fats are semi solids or solids (their melting points are more than 20° C ). A substance may be classed as fat in one season and oil in another season or the same glyceride may be solid at a hill station and liquid in plains. Thus, this distinction is not well founded as the physical state depends on climate and weather. (ii) The difference in oils and fats is actually dependent on the nature of monocarboxylic acid present in the glyceride. Oils contain large proportion of the glycerides of lower carboxylic acids, ( e.g. , butyric acid, caprylic acid and caproic acid) and unsaturated fatty acids, ( e.g. , oleic, linoleic and linolenic acids) while fats contain a large proportion of glycerides of higher saturated carboxylic acids, ( e.g. , palmitic, stearic acids). Lard (fat of hogs) is a solid fat and its composition in terms of fatty acids produced on hydrolysis is approximately 32% palmitic acid, 18% stearic acid, 45% oleic acid and 5% linolenic acid. Olive oil on the other hand, contains 84% oleic acid, 4% linoleic acid, 9% palmitic acid and 3% stearic acid. (2) Physical Properties of oils and Fats (i) Fats are solids, whereas oils are liquids. (ii) They are insoluble in water but soluble in ether, chloroform and benzene. (iii) They have less specific gravity than water and consequently float on the surface when mixed with it.
mixture is acidified with dilute sulphuric acid and steam distilled. The distillate is cooled, filtered and titrated against 0.1 N KOH. (5) Uses (i) Many oils and fats are used as food material. (ii) Oils and fats are used for the manufacture of glycerol, fatty acids, soaps, candles, vegetable ghee, margarine, hair oils, etc.
(iii) Oils like linseed oil, tung oil, etc., are used for the manufacture of paints, varnish, etc. (iv) Castor oil is used as purgative and codliver oil as a source of vitamins A and D. Almond oil is used in pharmacy. Olive oil is also used as medicine. (v) Oils are also used as lubricants and illuminants.
Table : 28.4 Difference between vegetable oils and Mineral oils Property Vegetable oils Minerals oils
- Composition These are triesters of glycerol with higher fatty acids.
These are hydrocarbons (saturated). Kerosene oil–Alkanes from C 12 to C 16.
- Source Seeds root and fruits of plants. These occur inside earth in the form of petroleum.
- Hydrolysis Undergo hydrolysis with alkali. Form soap and glycerol.
No hydrolysis occurs.
- On adding NaOH and phenolphthalein
Decolourisation of pink colour occurs. No effect.
- Burning Burns slowly Burn very readily.
- Hydrogenation Hydrogenation occurs in presence of nickel catalyst. Solid glycerides (fats) are formed.
No hydrogenation occurs.
(6) Soaps : Soaps are the metallic salts of higher fatty acids such as palmitic, stearic, oleic, etc. The sodium and potassium salts are the common soaps which are soluble in water and used for cleansing purposes. Soaps of other metals such as calcium, magnesium, zinc, chromium, lead, etc., are insoluble in water. These are not used for cleansing purposes but for other purposes (lubricants, driers, adhesives, etc.) Ordinary soaps (sodium and potassium) are the products of hydrolysis of oils and fats with sodium hydroxide or potassium hydroxide. The oils and fats are mixed glycerides and thus soaps are mixtures of salts of saturated and unsaturated long chain carboxylic acids containing 12 to 18 carbon atoms. This process always yields glycerol as a byproduct.
Soap
1
3
2 Glycerol
2
2
| | Triglyceride
2 1
2 3
2
| | 3
R COONa
RCOONa
RCOONa
CHOH
CHOH
NaOH CHOH
CHOCOR
CHOCOR
C HOCOR
There are three methods for manufacture of soaps : (i) The cold process (ii) The hot process
(iii) Modern process (7) Synthetic Detergents : The synthetic detergents or Syndets are substitutes of soaps. They have cleansing power as good or better than ordinary soaps. Like soap, they contain both hydrophilic (water soluble) and hydrophobic (oil-soluble) parts in the molecule.
Sodiumpalmitatepar(Soap)^ t
Hy drophobi^15 p art^31 cHy drophilic Sodiumlaury lsulphatepart(Detergent^ )
Hy drophobi C part^12 H 25 c OSO Hy drophili^3 Na c C H COONa
Some of the detergents used these days are given below: (i) Sodium alkyl sulphates : These are sodium salts of sulphuric acid esters of long chain aliphatic alcohols containing usually 10 to 15 carbon atoms. The alcohols are obtained from oils or fats by hydrogenolysis. CH Lauryl 3 ( CH alcohol 2 ) 10 CH 2 OH Sulphuric HO acid SO 3 H
CH CH CHOSO OH NaOH (^3) Lauryl (^2) hydrogen (^102) sulphate 2 ( )
CH Sodium 3 ( CH lauryl 2 ) (^10) sulphate CH 2 OSO (Detergent 2 ONa )
The other examples are sodium cetyl sulphate, C (^) 16 H 33 OSO 2 ONa^ and^ sodium^ stearyl^ sulphate, CH (^) 3 ( CH 2 ) 16 CH 2 OSO 3 Na. Unlike ordinary soaps, they do not produce OH –^ ions on hydrolysis and thus can be safely used for woollen garments. (ii) Sodium alkyl benzene sulphonates : Sodium p - dodecyl benzene sulphonate (S.D.S.) acts as a good detergent. It is most widely used since 1975.
CH 3 ( CH 1 - Dodecene 2 ) 9 CH CH 2 C 6 H 6 AlCl ^3 2 - Dodecy l benzene 6 5
|^3 3 (^2 ) 9 CH
CH
CH CH CH
iiNaOH
iHSO ( ) (^ ) ^2 ^4 (S.D.S.) 6 4 3
|^3 3 (^2 ) 9 CH SONa
CH
CH CH CH
These long chain alkyl benzene sulphonate (L.A.S.) are most widely used syndets. (iii) Quaternary ammonium salts : Quaternary ammonium salts with long chain alkyl group have been used as detergents, e.g. , trimethyl stearyl ammonium bromide.
( 3 ) (^3) C 18 H 37 CH N Br (iv) Sulphonates with triethanol ammonium ion in place of sodium serve as highly soluble materials for liquid detergents.
^ R O SO 2 NH ( CH 2 CH 2 OH ) 3 (v) Partially esterified polyhydroxy compounds also acts as detergents.
Pentaerythritolmonostearate
2
2
2
| (^17 352) | H
CHOH
CHOH
C H COOCH C CHO
Detergents are superior cleansing agents due to following properties. (i) These can be used both in soft and hard waters as the calcium and magnesium ions present in hard water form soluble salts with detergents. Ordinary soap cannot be used in hard water. (ii) The aqueous solution of detergents are neutral. Hence these can be used for washing all types of fabrics without any damage. The solution or ordinary soap is alkaline and thus cannot be used to wash delicate fabrics. (8) Waxes : Waxes are the esters of higher fatty acids with higher monohydric alcohols. The acids and alcohols commonly found in waxes are palmitic, cerotic acid ( C 25 H 51 COOH ), melissic acid ( C 30 H 61 COOH ) and
cetyl alcohol (^) ( C 16 H 33 OH ), ceryl alcohol (^) ( C 26 H 53 OH ), myricyl alcohol ( C 30 H 61 OH ), etc. Waxes are insoluble in water but are readily soluble in benzene, petroleum, carbon disulphide etc. Waxes on hydrolysis with water yields higher fatty acids and higher monohydric alcohols. (^15) Cetyl palm (^31) itate (^1633215) Palmitic (^31) acid Cetyl (^16) alcohol 33 C H COOC H HO C H COOH C H OH When hydrolysis is carried with caustic alkalies, soap and higher monohydric alcohols are formed. C 15 (^) H 31 COOC 16 H 33 NaOH C 16 H 33 OH Sodium C 15 H palmitate 31 COONa (Soap) The common waxes are: (i) Bees wax, Myricyl palmitate, C 15 H 31 COOC 30 H 61 (ii) Spermaceti wax , Cetyl palmitate, C 15 H 31 COOC 16 H 33 (iii) Carnauba wax , Myricyl cerotate, C 25 H 51 COOC 30 H 61 Waxes are used in the manufacture of candles, polishes, inks, water proof coating and cosmetic preparations. Waxes obtained from plants and animals are different than paraffin wax which is a petroleum product and a mixture of higher hydrocarbons (20 to 30 carbon atoms). So paraffin wax is not an ester. Candles are prepared by mixing paraffin wax (90%) with higher fatty acids like stearic and palmitic. The fatty acids are added to paraffin wax as to give strength to candles. The mixture is melted and poured into metal tubes containing streched threads. On cooling candles are obtained.
Substituted carboxylic acids
The compounds formed by the replacement of one or more hydrogen atoms of the hydrocarbon chain part of the carboxylic acids by atoms or groups such as X (halogen), OH or NH 2 , are referred to as substituted acids. For example, CH Chloroacet 2 ClCOOH icacid ; Hydroxyace (^2) ticacid CHOHCOOH ; CH Aminoaceti 2 NH 2 COOH cacid
The position of the substituents on the carbon chain are indicated by Greek letters or numbers. C ^6 C ^5 C^4 C ^3 C ^2 C^1 OOH For example,
(i) d + Tartaric acid-Dextro-rotatory (ii) l – Tartaric acid-Leavorotatory
(iii) Meso tartaric acid-optically inactive due to internal compensation.
(3) Chemical Properties
(4) Uses : It is used in carbonated beverages and effervescent tablets, in making baking powder (cream of tartar) and mordant in dyeing (potassium hydrogen tartrate), in preparing Fehling's solution (sodium potassium tartrate–Rochelle salt), in medicine as emetic, dyeing and calico-printing (tartar emetic- potassium antimonyl tartrate) and silver mirroring. (5) Tests (i) When heated strongly, tartaric acid chars readily giving a smell of burnt sugar to produce free carbon and pyruvic acid. (ii) With AgNO 3 : A neutral solution of tartaric acid gives a white ppt. which is soluble in ammonia. A silver mirror is obtained on warming the ammonical silver nitrate solution (Tollen's reagent). (iii) With Fenton's reagent : ( H 2 O 2 containing a little of ferrous salt) and caustic soda, It gives a violet colour. (iv) With Resorcinol and conc. H 2 SO 4 : It gives blue colour. Citric Acid Or 2 - Hydroxypropane Or 1,2,3-Tri Carboxylic Acid Or - Hydroxy Tricarballylic Acid It occurs in the juice of citrus fruits such as lemon, galgal, orange, lime, etc. Lemon juice contains 6 - 10% of citric acid.
(1) Methods of Preparation (i) By Fermentation : Citric acid is obtained by carrying fermentation of dilute solution of molasses with micro-organism, Aspergillus nigar , at 26-28° C for 7 to 10 days. The resulting solution is neutralised with Ca ( OH ) 2 to form insoluble precipitate, calcium citrate. It is decomposed by dilute H 2 SO 4. The CaSO 4 is filtered off and the solution is concentrated under vacuum to get crystals of citric acid. (ii) By Lemon juice : It is also obtained from lemon juice. The juice is boiled to coagulate proteins. From clear solution, citric acid is obtained as calcium salt with (^) Ca ( OH ) 2.
(iii) By synthetic method CHCl
CHCl
CO
CHCl
CHCl
CHOH
CHOH
CHOH
C HOH HClg HNOO
2
2
| [] |
dil.
2
2
| (in aceticheatacid)|
() Gly cerol
2
2
| | ^ ^ ^ ^3
CHCl
CHCl
CN C OH
CHCN
CHCN
CN C OH
CHCOOH
CHCOOH
C OHCOOH HOH KCN
2
2
| |
2
2
| |
/
2
2
| |(^ ) ^2 ^ ^
Optical active
Malicacid
| Sucinicacid
| (^) Heat 2 2
2 CH COOH
CHOHCOOH CHCOOH
CH COOH HI
CHOHCOOH
Pot. CHOHCOOK | acidtartrate
T artaricacid CHOHCOOHCHOHCOOH |
and CHOHCOOK
Potassium CHOHCOOK | tartrate
It forms two series of CH Pyruvic 3 COCOOH acid salts Dihydroxymeleicacid
| |( ) ( ) COH COOH
COHCOOH
Heat
HBr ,'Dibromosuccinicacid
| ^ CHBrCOOH
CHBrCOOH AgN O 3 NH 4 OH
Tartronic acid + Sliver mirror (Test of tartaric acid)
Oxalicacid
| | ( ) 2 27 / 2 4
[] COOH
COOH COOH
CHOHCOOH KCrOH SO O^
Fehling's solution
HI Heat
Oxalicacid
| T artronicacid
|
( ) [] COOH
COOH COOH
CH OHCOOH O Complex formation NaOOCCH O
NaOOCCH O |^ Cu O HC COONa
O HC COONa
(^) |
Fenton'sreagent
[ O ] Fe^2 / H 2 O 2
HCN
(2) Physical Properties : It is a colourless crystalline compound. It possesses one water molecule as water of crystallisation. It is soluble in water and alcohol but less soluble in ether. It is not optically active compound. It is nontoxic in nature. It behaves as an alcohol and tribasic acid. (3) Chemical properties
(4) Uses : It finds use in making lemonades, as acidulant in food and soft drinks and makes the lemon sour, as mordant in dyeing and calico printing. Ferric ammonium citrate, magnesium citrate (as an antacid and laxative), sodium or potassium citrate are used in medicine. Ferric ammonium citrate finds use in making blue prints.
Aromatic Carboxylic Acids
Aromatic acid contain one or more carboxyl group ( COOH ) attached directly to aromatic nucleus. Examples
Aromatic acid containing- COOH group in the side chain, they are considered as aryl substituted aliphatic acid. Examples
Benzoic Acid (1) Methods of Preparation (i) From oxidation of Benzyl alcohol [Laboratory method]
(ii) From hydrolysis of nitriles or cyanides
(iii) From Grignard reagent
(iv) By hydrolysis of esters
Methyl ben^6 5 zoate 3 2 Benzoic^65 acid Methanol^3
C HCOOCH HO H^ orOH CHCOOH CHOH (v) From trihalogen derivatives of hydrocarbons
(vi) From benzene
(vii) From Toluene
Acetoneaciddicarboxyl ic
2
2
CH COOH
CO
CHCOOH
Citricacid
|
( )
|
2
2
CH COOH
COHCOOH
CHCOOH
M onoacelyderivative
|
( )
|
2
3
2
CH COOH
COCOCH COOH
CHCOOH
Aconiticacid
2
CHCCOOH^ | COOH
CHCOOH
Heat, 150° C
With alkalies and alcohols, it forms three series of salts and esters, respectively
CH 3 COCl HCl
Hl reductio n
Tricarballyticacid
|
|
2
2
CH COOH
CHCOOH
CHCOOH
Fuming H 2 SO 4 heat
CH 2 COOH
Phenyl acetic acid
CH = CHCOOH
Cinnamic acid
O
CH 2 OH
Benzyl alcohol
CHO
Benzaldehyde
O
COOH
Benzoic acid
H OH+^ or–
COOH
Benzoic acid
CN
Benzonitril e
+ 2 H 2 O + 2 NH 3
Mg I
Phenyl mag. iodide
O
+ C = O
C –
OMgI
Addition product
O
H +^ , H 2 O
COOH
Benzoic acid
+ Mg OH I
CCl 3
Benzotrichlor ide
C(OH)
3
Unstabl e
COOH
Benzoic acid
+ H 2 O
[Friedel-craft reaction]
COCl (^) COOH COCl 2 AlCl 3
H 2 O / NaOH
H 3 C COOH [ O ], KMnO 4 / OH or alkaline K 2 Cr 2 O 7
COOH
Benzoic acid
COOH
O-toluic acid
CH 3
Phthalic acid
COOH
COOH
Salicylic acid
COOH
OH
Anthranilic acid
COOH
NH 2
m - Nitro benzoic acid
COOH
NO 2
