Outstanding results in hydrogenation reactions over heterogeneous copper catalysts

A review. The most recent results obtained in hydrogenation reactions with heterogeneous copper catalysts prepd. with non conventional chemisorption-hydrolysis technique are reviewed. In particular, the hydrogenation of isopulegol to give menthol can be selectively realized, though the redn. of an isolated double bond is quite unusual for copper. Starting from citronellal by exploiting the acidic properties of the catalysts for the ene reaction, allows to obtain (-)-menthol in one step with a yield of 88% and a stereoselectivity of 80%. Moreover results obtained in the hydrogenation of vegetable oils are reported. A selective hydrogenation could improve their oxidative stability, without worsen the cold properties, allowing to use these materials as lubricants. Other important results were obtained in the chemoselective hydrogenation of carbonyl compds. such as cyclohexanones, steroids and unsatd. aliph. ketones under very mild exptl. conditions, that means atm. hydrogen pressure and 60-90°C.