Introduction, nomenclature, classification, isomerism in ether

Nomenclature of ethers

Common names of ethers follow after the names of alkyl / aryl groups written as separate words in alphabetical order. The word ether is added at the end.

In case of simple ethers, the prefix di is attached before the name of the alkyl group.

Examples:

C₂H₅ - O - C₂H₅ is Diethyl ether

C₆H₅ - O - C₆H₅ is Diphenyl ether

C₂H₅ - O - C₆H₅ is Dthyl phenyl ether.

According to the IUPAC nomenclature ethers are regarded as hydrocarbon derivatives in which a hydrogen atom is replaced by an alkoxy group - OR, the larger group (R) being chosen as the parent hydrocarbon. Ethers are named as alkoxyalkenes. The larger alkyl group forms the part of parent chain while lower alkyl group constitutes the alkoxy radical.

Examples:

The numbering of the parent chain is done so that the carbon atom linked to the -O-atom gets the lowest number.

Classification of ether

Ethers are known as simple or symmetrical, if the two alkyl or aryl groups attached to the oxygen atom are same.

Example: C₂H₅ - O - C₂H₅ is called diethyl ether and is a simple ether.

Ethers are known as mixed or unsymmetrical if the two groups attached to the oxygen atom are different.

Example: C₂H₅ - O - CH₃ called ethyl methyl ether is a mixed ether.

Isomerism in ether

Aliphatic Ethers can give two different types of isomers.

1. Chain isomerism

Ethers with the same formula and having different carbon chain skeletons are called chain isomers.

Examples:

2. Functional isomers

Ethers are isomeric with alcohols.

Example:

is isomeric with ethyl alcohol C₂H₅OH.

3. Metamerism

Isomers with the same molecular formula but different alkyl groups (around the functional group) are called metamers. An ether with formula C₄H₁₀O has 3 metamers.