Hydration of Alkenes

The addition of water (hydration) across the double bond of an alkene yields an alcohol. Alkenes are available as products of coal tar and petroleum refining,and a variety of catalytic conditions can support the addition of water across the double bond. In most cases, water adds in the direction that places the new hydroxyl group on the more highly substituted end of the double bond according to the Markovnikov rule, as in acid-catalyzed hydrations. (The more highly substituted end of the double bond is the one that is bonded to more carbon atoms.