Ethers

Ethers are organic compounds in which an oxygen atom forms single bonds to two alkyl or aryl groups, written as R–O–R'. They include symmetrical ethers (R = R') and unsymmetrical ethers (R ≠ R'), as well as cyclic ethers such as tetrahydrofuran (THF) and 1,4-dioxane. The simplest examples are dimethyl ether and diethyl ether.

Physical properties of ethers include being colorless liquids or gases at room temperature, with a polar C–O–C linkage. They generally have higher boiling points than alkanes of comparable molecular weight but lower than alcohols, because ethers do not donate hydrogen bonds. Ethers are good solvents for a wide range of organic reactions and for some inorganic salts, owing to their polarity and ability to stabilize cations through coordination with the oxygen lone pairs.

Reactivity and safety: Ethers are relatively inert toward many reagents but can be cleaved by strong acids or strong Lewis acids. They can coordinate to metal centers as ligands. A notable safety concern is the formation of peroxides upon prolonged storage in air, especially with diethyl ether and other simple ethers, which can pose explosion hazards. Proper storage away from heat and light is advised.

Synthesis and reactions: The Williamson ether synthesis couples an alkoxide with a primary alkyl halide to form an ether (R–O–R'). Industrially, ethers are often produced by acid-catalyzed dehydration of alcohols, though this method can yield mixtures of products. Cyclic ethers such as THF and 1,4-dioxane arise from intramolecular dehydration or ring-forming reactions.

Applications: Ethers are widely used as solvents in laboratory and industrial processes, in polymerization, and in pharmaceutical manufacturing. Some ethers, such as diethyl ether, have historical uses as anesthetics, while others serve as building blocks for chemicals and materials.