Answer to Question #125541 in Organic Chemistry for Owusu ansah kwasi

Question

Write short notes on the classsifications of alcohol in the context of organic chemistry

Answer 1

Classifications of alcohol: Alcohols may be classified as mono–, di–, tri- or polyhydric compounds depending on whether they contain one, two, three or many hydroxyl groups respectively in their structures as given below:

Monohydric alcohols may be further classified according to the hybridisation of the carbon atom to which the hydroxyl group is attached.

(i) Compounds containing C_sp3− OH bond: In this class of alcohols, the –OH group is attached to an sp³ hybridised carbon atom of an alkyl group. They are further classified as follows:

Primary, secondary and tertiary alcohols: In these three types of alcohols, the –OH group is attached to primary, secondary and tertiary carbon atom, respectively as depicted below:

Allylic alcohols: In these alcohols, the —OH group is attached to a sp³ hybridised carbon adjacent to the carbon-carbon double bond, that is to an allylic carbon.

Benzylic alcohols: In these alcohols, the —OH group is attached to a sp³ hybridised carbon atom next to an aromatic ring.

Allylic and benzylic alcohols may be primary, secondary or tertiary.

(ii) Compounds containing C_sp2− OH bond: These alcohols contain —OH group bonded to a carbon-carbon double bond, i.e., to a vinylic carbon or to an aryl carbon. These alcohols are also known as vinylic alcohols.

Vinylic alcohol: CH2 = CH – OH