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Carboxylic Acids and Its Derivativs >>
Carboxylic Acid Anhydrides
(ii) Carboxylic acid anhydrides
Carboxylic acid anhydrides can be used to prepare esters and amides.
O O O O || || || ||R – C – O – C – R ———→ R – C – OR' + R – C – OH NH3 ↓ excess O O || || R – C – NH2 + R – C – O– NH4+
Anhydrides can be hydrolysed to get back acids.
O O O || || H2O ||R – C – O – C – R ————→ 2R – C – OH
Illustration 25:
The compound (X) is
(A) CH3COOH (B) BrCH2 – COOH
(C) (CH3CO)2O (D) CHO – COOH
Solution:
(C)
Exercise 10:
(iii) Esters
Ester hydrolysis
Acid catalysed esterification is an essentially reversible reaction. If you follow the backward course of reactions of esterification it gives you the mechanism for ester hydrolysis.
O O
|| H2O ||
R – C – OR' ————→ R – C – OH + R'OH