Question

How will you obtain the following: 
(i) Diethyl ether from Sodium ethoxide 
(ii) Benzyl alcohol from Benzyl chloride 
(iii) Propan-1-ol from Ethyl Magnesium bromide 
 

Hint:

Williamson synthesis → ethers, Hydrolysis of alkyl/aryl halides → alcohols, Grignard reagents + formaldehyde → primary alcohols.

Answer 1

(i) Diethyl ether from Sodium ethoxide:
This can be prepared by Williamson Ether Synthesis. Sodium ethoxide reacts with ethyl iodide (or ethyl bromide) to form diethyl ether.
\[ C_2H_5ONa + C_2H_5I \;\; \longrightarrow \;\; C_2H_5OC_2H_5 + NaI \] (ii) Benzyl alcohol from Benzyl chloride:
Benzyl chloride undergoes hydrolysis with aqueous NaOH (or KOH) to give benzyl alcohol.
\[ C_6H_5CH_2Cl + NaOH(aq) \;\; \longrightarrow \;\; C_6H_5CH_2OH + NaCl \] (iii) Propan-1-ol from Ethyl Magnesium bromide:
Ethyl magnesium bromide (Grignard reagent) reacts with formaldehyde, followed by hydrolysis, to give primary alcohol (propan-1-ol).
\[ C_2H_5MgBr + HCHO \;\; \longrightarrow \;\; C_2H_5CH_2OMgBr \] \[ C_2H_5CH_2OMgBr + H_2O \;\; \longrightarrow \;\; C_2H_5CH_2OH \; (Propan\!-\!1\!-\!ol) + Mg(OH)Br \] Conclusion:
- Williamson ether synthesis gives diethyl ether.
- Hydrolysis of benzyl halides yields benzyl alcohol.
- Grignard reagents with formaldehyde followed by hydrolysis yield primary alcohols.