Hydrogenation catalysts—Their effect on selectivity

Abstract Catalytic hydrogenation is an important reaction in the processing of fats and oils. During this process, the composition and properties of the lipid mixture are significantly modified. In addition to partial elimination of unsaturation, formation of geometric and positional isomers also occurs, yielding a complex mixture of products. Selectivity is a measure of the tendency for any of these reactions to occur relative to another and is influenced by both reaction conditions and the nature of the catalyst. In this review, the effects of various catalysts on the selectivity of the hydrogenation process are discussed in detail, while only a brief discussion of the effects of reaction conditions is given. The limitations of heterogeneous catalysts such as nickel, copper and platinum‐containing catalysts are reviewed with emphasis on recent literature. A similar discussion of homogeneous catalysts such as the soluble coordination complexes of transition metals is also given. While these complex catalysts have been extensively investigated in laboratory studies, they have not been used commercially due to their low activity, high cost, and difficult handling.