Blechner Center for Applied Catalysis and Process Development, Chemical Engineering Department

Ben-Gurion University of the Negev, Beer-Sheva Israel

Institutes for Applied Research, , Ben-Gurion University of the Negev, Beer-Sheva Israel

The demand for chiral compounds and intermediates for the fine chemicals, pharmaceutical, fragrance & flavor and agrochemical industries is increasing rapidly. Of the various techniques known for the preparation of specific optical isomers, asymmetric homogeneous syntheses, particularly those employing transition metal catalysis, have emerged as one of the most efficient methods.

Different methods have been applied in the design, preparation and characterization of chiral heterogeneous catalysts. First, the well-known nickel/tartaric acid/sodium bromide system, studied extensively in the asymmetric hydrogenation of b-ketoesters, was supported on mesoporous materials, actived carbon and graphite. The expected advantages, based on preliminary results, are improved performance of high metal loading, chiral catalysts that translate into high productivity and optical selectivity.

A novel approach was developed, based on homogeneous, high- performance Ru-binap [2,2'- bis(diphenylphosphino)1,1'-binaphthyl)] and Rh-DUPHOS complexes, entrapped into polymer films and membranes, prepared by selective and controlled crosslinking of appropriate functionalized macromonomers. Preliminary results of the asymmetric hydrogenation of methyl acetoacetate with this type of catalysts demonstrated the feasibility of this approach, yielding higher reaction rates in presence of acids and acidic polymers (e.g. sulfonated polymers).