Chapter 21, Problem 21.52AP

Interpretation Introduction

(a)

Interpretation:

The non-feasibility of given reaction is to be explained.

Concept Introduction:

Primary alcohol reacts with hydrogen bromide to form alkyl halide. The reaction proceeds via carbocation intermediate formation. Bromide ion acts as nucleophile which attacks the primary carbocation to form alkyl halide. As hydrogen bromide is strong acid so there will be considerable amount of bromide ion present in the reaction mixture. Hydrogen cyanide is a weak acid, so it will not dissociate completely to form cyanide and hydrogen ions. The cyanide ion acts as a nucleophile in the reaction.

Interpretation Introduction

(b)

Interpretation:

The non-feasibility of synthesis of half ester of adipic acid is to be explained.

Concept Introduction:

Esterification reaction is a reaction between carboxylic acid and alcohol to form an ester. In the first step, carbonyl oxygen of acid gets protonated, and then the carbocation of acid is formed. In second step, lone pair of oxygen atom of alcohol attacks the carbocation and ester is formed with elimination of water.

Interpretation Introduction

(c)

Interpretation:

The non-feasibility of synthesis of acetic benzoic anhydride is to be explained.

Concept Introduction:

Anhydride is compound containing two carbonyl functional groups, both connected to same oxygen atom. The dehydration of acid gives anhydride. Anhydride can be formed using acid and acyl chloride.

Interpretation Introduction

(d)

Interpretation:

The non-feasibility of saponification of methyl salicylate with one equivalent of $\text{NaOH}$ is to be explained.

Concept Introduction:

Saponification reaction is formation of carboxylic acid and alcohol from an ester. The bond between acid and alcohol is cleaved in the presence of base. It is hydration reaction of esters in presence of hydroxide ions.

Interpretation Introduction

(e)

Interpretation:

The non-feasibility of de-amidation reaction of cephalosporin derivative is to be explained.

Concept Introduction:

Amide bond is formed when a carboxylic acid and an amine undergoes condensation reaction. In the de-amidation reaction, the amide bond is cleaved to form carboxylic acid and amine. The reaction takes place in the presence of an acid.