Epoxides

Epoxides : a class of cyclic ether compounds with three-atom rings Strained ,more highly reactive than other ethers.

Epoxides are electrophilic due to strained three-membered ring system; nucleophilic attack at carbon releases the ring strain.

A compound containing the epoxide functional group can be called an epoxy, epoxide, oxirane, and alkeneoxide.

Epoxides are In general, low molecular weight ,colourless and nonpolar, and often volatile.

Synthesis

alkenes with peroxycarboxylic acids: 

Direct oxidation of alkenes with peroxycarboxylic . (PBA or mcpba)

(Note: Oxidation of alkene with performic or peracetic acid gives diol.)

Olefin oxidation using Ag₂O :

Oxidation of ethene with oxygen over a silver oxide catalyst at 300o:

Chlorohydrins to Epoxide :

Intramolecular SN₂ substitution:  In this case, an alkoxide ion intramolecularly displaces chloride.

Reactions

Ring-opening reactions dominate the reactivity of epoxides, as they are potent electrophiles.Alcohols, water, amines, thiols and many other reagents can act as nucleophile for this reaction.

This reaction is the basis of the formation of epoxy glues and the production of glycols.

Applications

Epoxides are used to assemble various polymers known as epoxies, which are excellent adhesives and useful surface coatings. Epoxides are alsoused to generate detergents and surfactants.

Common epoxy resins are based on reacting epichlorohydrin with bisphenol . Bisphenol is produced on an industrial scale by the condensation of phenol and acetone.

Epichlorohydrin is traditionally manufactured from allyl chloride in two steps, beginning with the addition of hypochlorous acid, which affords a mixture of two isomeric alcohols. In the second step, this mixture is treated with base to give the epoxide: