Alcohols - Introduction (Edexcel International AS Chemistry): Revision Note

Alcohols - Introduction

• Alcohols are a family of molecules that contain the hydroxyl functional group, -OH

• Their general formula is  C_nH_2n+1OH

• The nomenclature of alcohols follows the pattern alkan + ol

• If there are two -OH groups present the molecule is called a diol

The first four alcohols

• Methanol, CH₃OH

• Ethanol, CH₃CH₂OH

• Propan-1-ol, CH₃CH₂CH₂OH

• Butan-1-ol, CH₃CH₂CH₂CH₂OH

Classification of Alcohols

• Alcohols can be classed as primary, secondary and tertiary

Primary alcohols

• A primary alcohol contains a carbon atom, bonded to the -OH group, which is attached to one other carbon atom (or alkyl group)

Secondary alcohols

• A secondary alcohol contains a carbon atom, bonded to the -OH group, that is attached to two other carbon atoms (or alkyl groups)

Tertiary alcohols

• A tertiary alcohol contains a carbon atom, bonded to the -OH group, that is attached to three other carbon atoms (or alkyl groups)