Seaver A. Ballard

76 Selective Reduction of Unsaturated Aldehydes and Ketones by a Vapor-Phase Hydrogen Transfer Reaction

Selective reduction of the carbonyl group of α, β-unsaturated aldehydes and ketones has been achieved by a vapor-phase hydrogen transfer reaction using saturated primary and secondary alcohols as hydrogen donors. The preferred catalyst for the reaction, which is reversible, is magnesium oxide. Application to the reduction of acrolein to allyl alcohol, methacrolein to methallyl alcohol, crotonaldehyde to crotyl alcohol, and methyl isopropenyl ketone to 3-methyl-3-buten-2-ol is described. The effects of catalyst properties, the structure of the alcoholic hydrogen donor, and reaction conditions are discussed for acrolein reduction. A mechanism is proposed.