Epoxides are typically prepared by oxidation of alkenes. The most important epoxide in terms of industrial scale is ethylene oxide, which is produced by oxidation of ethylene with oxygen. Other epoxides are produced by one of two routes:
* By the oxidation of alkenes with a peroxyacid such as m-CPBA.
* By the base intramolecular nucleophilic substitution of a halohydrin.
Many ethers, ethoxylates and crown ethers, are produced from epoxides.