Chemistry · Ch 11 — Alcohols, Phenols and Ethers
Classification of Ethers
Classification of Ethers
Ethers are classified as symmetrical ethers (also called simple ethers) when the two alkyl or aryl groups bonded to the central oxygen atom are identical -- for example CH3-O-CH3 (dimethyl ether) or C6H5-O-C6H5 (diphenyl ether), matching the general patterns R-O-R and Ar-O-Ar. When the two groups bonded to the oxygen are instead different, the ether is called unsymmetrical (or mixed) -- for example CH3-O-C2H5 (ethyl methyl ether) or C6H5-O-CH3 (methyl phenyl ether, more commonly known by its trivial name anisole), matching the general patterns R-O-R' and Ar-O-Ar'. This symmetry-based classification is entirely independent of whether the ether is aliphatic (alkyl-alkyl), aromatic (aryl-aryl), or mixed alkyl-aryl in composition, and it also sits independently alongside the epoxide/cyclic-ether structural subtype introduced in section 11.1: an epoxide such as ethylene oxide, wh …
What this figure shows. Two pairs of worked examples: symmetrical (simple) ethers, where R-O-R or Ar-O-Ar' has identical groups on both sides of the oxygen, illustrated by CH3-O-CH3 (dimethyl ether) and C6H5-O-C6H5 (diphenyl ether); and unsymmetrical (mixed) ethers, where R-O-R' or Ar-O-Ar' has two different groups, illustrated by CH3-O-C2H5 (ethyl methyl ether) and C6H5-O-CH3 (methyl phenyl ether, i.e. anisole). The general Do-you-know box on epoxides (a cyclic ether) sits alongside this classification in the source, reinforcing that ring ethers are a structural subt …