Oxacyclopropanes hydrolysis

Ethanediol (ethylene glycol) is prepared by oxidation of ethene to oxacyclopropane, followed by hydrolysis, in quantities exceeding 20 million tons globally. Its low melting point (-11.5°C), its high boiling point (198°C), and its complete miscibility with water make it a useful antifreeze. Its toxicity is similar to that of other simple alcohols. 

Hydrolysis of oxacyclopropanes furnishes the products of anti dihydroxylation of an alkene... 

Treatment of oxacyclopropanes with water in the presence of catalytic acid or base leads to ring opening to the corresponding vicinal diols. These reactions follow the mechanisms described in Section 9-9 The nucleophile (water or hydroxide) attacks the side opposite the oxygen in the three-membered ring, so the net result of the oxidation-hydrolysis sequence constitutes an anti dihydroxylation of an alkene. In this way, tram-2-butene gives me50-2,3-butanediol, whereas ds-2-butene furnishes the racemic mixture of the 1R, >R and 2S,3S enantiomers. 

In Summary Peroxycarboxylic acids supply oxygen atoms to convert alkenes into oxacyclopropanes (epoxidation). Oxidation-hydrolysis reactions with peroxycarboxylic acids furnish vicinal diols in a stereospeciflcally anti manner. 

Oxidation of ethene with oxygen in the presence of silver furnishes oxacyclopropane (ethylene oxide), the hydrolysis of which gives 1,2-ethanediol (ethylene glycol) (Section 9-11). Hydration of ethene gives ethanol (Section 9-11). 

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