Question

Explain continuous etherification process for the preparation of diethyl ether.

Answer 1

Ethers are organic compounds with $R - O - R$ group. The process of dehydration of alcohols to form ethers is known as etherification and continuous etherification is the process of producing ethers from simple alcohols by acid catalysis. The preparation of diethyl ether by continuous etherification is carried out in two steps.

Complete step by step answer:
Ethers are organic hydrocarbons in which the hydrogen atom is replaced by the $- OR$ or $- OAr$ group and here $R$ and $Ar$ groups represent alkyl and aryl groups. In the naming of ether compounds, the larger group is taken as the parent hydrocarbon. They are unreactive and are used as solvents for perfumes, dyes and various other products. The lower members of ether are soluble in water as they form hydrogen bonds with water molecules. Solubility of ether compounds decreases with increase in the number of carbon atoms.
Etherification is the process of dehydration of alcohols to form ethers. The process of esterification to produce ethers from alcohols is carried out by both aliphatic and aromatic alcohols whereas the simple aliphatic alcohols can be used to produce ethers by sufficient acid catalysis. The process of acid catalysis to produce ethers from alcohols is known as continuous etherification which involves mixing of reactants and removal of product at the same time.
For the given question, the continuous etherification process for the preparation of diethyl ether is carried out in two steps.
Step 1: This involves the formation of ethyl hydrogen sulphate. Ethyl hydrogen sulphate is formed when $Conc. {H_2}S{O_4}$ is heated with excess ethyl alcohol.
{C_2}{H_5} - O - H + H - O - S{O_3}H \to {C_2}{H_5} - O - S{O_3}H \\\ {{ }}{{{ }}_{{{ }}{{{ }}^{{{_{{{Conc}}{{.}}}}_{{H_2}S{O_4} - {H_2}O}}}}}} \\\
Ethyl alcohol Ethyl hydrogen sulphate
Step2: After the first step, diethyl ether if formed when ethyl hydrogen sulphate reacts with excess of ${C_2}{H_5}OH$
{{ }}{{{ }}_{{{413K}}}} \\\ {C_2} - O - S{O_3}H{{ }} + {{ }}OH - {C_2}{H_5}{{ }} \to {{ }}{C_2}{H_5} - O - {C_2}{H_5} + {H_2}S{O_4} \\\
Ethyl hydrogen sulphate Ethyl alcohol Diethyl ether

Note:
Diethyl ether is an unreactive compound which is therefore more suitable for being used as a solvent and is used as the starting fluid for many engines. It causes unconsciousness and respiratory problems when it is inhaled and may even cause irritation in the eyes but these effects can be removed when not exposed to the compound anymore.