Question

Propose at least three methods to convert ${\mathbf{C}}_{\mathbf{6}}{\mathbf{H}}_{\mathbf{5}}{\mathbf{CH}}_{\mathbf{2}}{\mathbf{CH}}_{\mathbf{2}}\mathbf{Br}\mathbf{}\mathbf{to}\mathbf{}{\mathbf{C}}_{\mathbf{6}}{\mathbf{H}}_{\mathbf{5}}{\mathbf{CH}}_{\mathbf{2}}{\mathbf{CH}}_{\mathbf{3}}$

Short answer

Method 1

Method 2

Method 3

Step-by-step solution

 Step 1: Preparation of alkane from an alkyl halide

Alkane can be prepared from alkyl halide by following three methods:

1. Elimination reaction
2. Hydrolysis of Grignard reagents
3. Nucleophilic substitution on the alkyl halide

Reactions involved in the three mechanism

Method 1Anelimination reaction involves alkyl halide and base. The base abstracts and forms alkene. Alkene is reduced by the catalytic reduction method, and alkane is formed.

Elimination reaction

Method 2

Hydrolysis of Grignard reagent: Alkyl halide is treated with magnesium in dry ether to form a Grignard reagent, which on hydrolysis gives alkane.

Hydrolysis of Grignard reagent

Method 3:

The nucleophilic substitution of halide ion is done by cyanide ion. Hydrolysis of cyanide ion forms carboxylic acid. Ammonium hydroxide reaction with carboxylic acid forms ammonium salt.Finally, decarboxylation of ammonium salt occurs to form alkane.

Substitution reaction