Ethers are class of organic compounds that contain ether group – an oxygen atom connected to two alkyl groups or aryl groups. They have the general formula R – O – R′, where R and R′ represents the alkyl or aryl groups. Ether, like water have a tetrahedral geometry i.e., oxygen is sp3 hybridised. The C – O – C bond angle in ethers is slightly greater than the tetrahedral angle due to repulsive interactions between the two bulky groups when they are attached to oxygen.

Dehydration of alcohol to ethers is catalyzed by:

Conc. \(H_2SO_4\) at 413 K

The correct answer is option 1. Conc. \(H_2SO_4\) at 413 K.

Symmetrical ethers can be made from the acid-catalyzed dehydration of primary alcohols. A classic example is the heating of ethanol at 130-140 °C to give diethyl ether. The reaction proceeds through the protonation of a hydroxyl group to give the conjugate acid followed by an \(S_N2\) reaction to give the symmetrical ether. The process works best for making symmetrical ethers of primary alcohols.

Mechanism: Synthesis Of Symmetrical Ethers via Acid-Catalyzed Dehydration of Alcohols

There are three key steps.

First of all, one equivalent of alcohol is protonated to its conjugate acid – which has the good leaving group, \(OH_2\) (water, a weak base).

Next, another equivalent of the alcohol can now perform nucleophilic attack at carbon \((S_N2)\), leading to displacement of \(OH_2\) (water) and formation of a new \(C-O\) bond. This is an \(SN_2\) reaction.

The final step is deprotonation of the product by another equivalent of solvent (or other weak base), resulting in our ether product.