Question

How can the following conversion be carried out?
Ethanol to propanenitrile

Answer 1

Hint: The product of the given conversion contains a cyanide group which is easily introduced by substitution reaction to any alkyl halide.

Complete step by step answer:
-Ethanol is an organic compound having an alcohol functional group. Ethanol is the higher homologue of methanol which is the simplest alcohol. The ethanol contains an ethyl group attached to a hydroxyl group. Thus the chemical formula of ethanol is \[C{H_3}C{H_2}OH\].
-The propanenitrile is an organic compound having a cyanide functional group. The number of carbon atoms is three in this compound. The cyanide group is a good nucleophile and can easily displace a good leaving group from a compound. Thus alkyl halides are used as starting materials to introduce cyanide group by displacement of the halide group.
-Specifically alkyl bromides or iodides are used as starting material because aliphatic bromide or iodide are better for leaving the group due to greater stabilization of the anion. The fluorides or chlorides are not good leaving groups for aliphatic halides.
-Thus the retrosynthesis for the compound is written as:

-The bromides are easily prepared from the corresponding alcohol using phosphorus tribromide. Thus the conversion from ethanol to propanenitrile is carried out in the following manner.

Note:
The haloalkane (\[R - X\]) is a vital intermediate in organic synthesis. Several nucleophiles can be introduced using the corresponding bromide or iodide. The Williamson ether synthesis is a very important reaction in organic chemistry for the preparation of ethers. For this the alcohols are treated with alkyl halides. Amines are also introduced in a similar way by replacing the halide group.