Which of the following ethers can be formed in good yield by condensation of the corresponding alcohols? For those that cannot be formed by condensation, suggest an alternative method that will work.

(a) Di butyl ether

(b)Ethyl n-propyl ether

(c) Di-sec-butyl ether

The cheapest method for synthesizing simple symmetrical ethers is the acid catalyzed bimolecular condensation where two molecules of alcohols are joined with the loss of a small molecule like water.The alcohol must have an unhindered primary alkyl group to form an ether and also the temperature of the reaction should not be too high. Bimolecular condensation of alcohols is considered to be a poor synthetic method.

The most reliable and versatile method for synthesis of ethers is given by Williamson method. In this method, attack of an alkoxide ion takes place on an unhindered primary alkyl halide or tosylate. The yield is poor if secondary alkyl halide is used. The alkoxide is generally made by adding to the alcohol.

(a) is a symmetrical ether and hence good yield can be produced by condensation method.

(b) is an unsymmetrical ether and hence good yield cannot be produced by condensation method. In such case, Williamson ether synthesis can eb used for good yields.

(c) is a symmetrical ether and hence good yield can be produced by condensation method.