In case of simple ethers, the prefix di is attached before the name of the alkyl group.Examples:
C2H5 - O - C2H5 is Diethyl etherC6H5 - 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.
The numbering of the parent chain is done so that the carbon atom linked to the -O-atom gets the lowest number.
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
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.
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.