study material-chemistry-organic chemistry
Carboxyllic-Acid-5
(vi) Arndt eistert reaction
The reaction consists in increasing the length of the carbon chain by introdusing one methylene group in carboxylic acids.
The reaction contains the following phases in its mechanism.
(viii) Fisher speir method or Esterification :
When carboxylic acid reacts with alcohol in the presence of acidic medium, they form esters with fruity smell. In this reaction, alcohol acts as a nucleophile and attack at electrophilic site of carboxylic acids.
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Mechanism of reaction
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It is evident from the above mechanism that this reaction involves cleavage of O – H bond of alcohol and not the C – O bond. It has been further established by isotope tracer technique.
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(ix) Hunsdicker Reaction :
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When carboxylic acid with a-hydrogen atom, reacts with halogen in the presence of phosphorous to form a-haloacids. These derivatives are easily converted into hydroxy acid and aminoacids by subsequent treatment with alkali and ammonia.