Methods of preparation and chemical reaction of aromatic carboxylic acid

1. Prepared By
Ms.Sayyed Mohsina
Aromatic Carboxylic Acid

2. “Do not give up
the Beginning
is always the
Hardest.”
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3. CONTENT
METHOD OF PREPARATION OF AROMATIC CARBOXYLIC ACID
1.Oxidation of primaryalcohols and aldehyde
2.Hydrolysis of nitrile
3.Carbonation of grignard reagent
4.Oxidation of carbon side chain
5. Hydrolysis of trichloromethyl group on benzene nucleus
6.Friedel craft reaction
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4. 4
CONTENT
REACTIONS OF CARBOXYLIC ACID
1.Esterification
2.Anhydride formation
3.Acid halide formation
4. Acid amide formation
5.Decarboxylation
6. Reduction
7. Electrophilic substitution in benzene ring

5. Method of Preparation of
Aromatic Carboxylic Acid

6. Oxidation of Primary Alcohols and
Aldehydes
Primary aromatic alcohols can be oxidized to aromatic
carboxylic acid.
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7. Hydrolysis of Nitriles
Hydrolysis of nitriles provide carboxylic acid.
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8. Carbonation of Grignard Reagents
Reaction of grignard reagent with carbon dioxide can be used to
preparearomatic carboxylic acid.
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9. Oxidation of carbon side-chains
Oxidation of alkyl benzene using strong oxidizing agent give benzoic
acid.
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10. Hydrolysis of Trichloromethyl group on
benzene nucleus
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Benzotrichloride on hydrolysis yield benzoic acid.

11. Friedel-Craft Reaction
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Benzene in presence of aluminium trichloride react with carbonyl
chloride give benzoyl chloride which on hydrolysis give benzoic acid.

12. Reactions of Aromatic
Carboxylic Acid

13. Esterification
Aromatic acids having no substituent in the ortho position to COOH group, are
readily converted into esters by direct reaction with alcohols in the presence of
mineral acids (HCl or H2SO4) as catalyst.
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If, however, the ortho substituent is present, the rate of esterification is
considerablyreduced.
When both ortho positions are occupied, esterification does not occur at all.
Esterification....

15. Anhydride Formation
The reaction of an aromatic acid chloride with sodium salt of the acid
yields the anhydride.
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16. Acid Halide Formation
Aromatic acids are converted to the corresponding acid halides by heating
with phosphoruspentachloride or with thionyl chloride.
The aromatic acid chlorides are insoluble in water and react with it very
slowly. Hence alcohols, phenols and amines can be acylated in aqueous
solution. When the acylation reaction is carried in the presence of alkali
(NaOH), it is catalysed and the HCl formed in the reaction mixture is
removed. This is called SchottenBaumann Reaction.
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Acid Halide Formation....

18. Acid Amide Formation
Aromatic acids form ammonium carboxylates which upon heating yield
acid amides.
In the presence of phosphorus pentoxide, amides further dehydrate to form
nitriles.
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19. Decarboxylation
Aromatic acids are readily decarboxylated by heating their salts with
sodalime.
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20. Reduction
Aromatic acids on reduction with lithium aluminium hydride give benzyl
alcoholsin 80 to 99 percent yield.
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21. Electrophilic Substitution in
Benzene Ring
Aromatic acids undergo electrophilic substitution reactions in the benzene
ring. The COOH group is meta director and the substitution takes place less
readily than in the parent hydrocarbon ring. For example, benzoic acid
undergoes halogenation, nitration and suiphonation giving m-chlorobenzoic
acid, m-nitrobenzoic acid and m-benzenesulphonicacid.
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Benzoic acid undergoes nitration giving m-nitrobenzoic acid.
Electrophilic Substitution in
Benzene Ring.....

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