| abstract |
A low cost, viable and modular method to prepare new, highly selective "catalytic membranes" and their use in various types of reactors is described. The membranes are versatile and reusable with negligible catalyst leaching, particularly in the asymmetric hydrogenation of substituted α, β-unsaturated acids or esters. The membranes comprise a hybrid inorganic/polymeric support material (i) and a molecular catalyst (ii) immobilized onto them, wherein: - (i) consists of a hybrid inorganic/polymeric compound in which inorganic compounds and organic polymers are chemically combined; - the inorganic compound is at least one selected from silicic, tungstic, molybdic and stannic acid compounds; - the organic polymers have hydroxy groups, preferably being polyvinylalcohol (PVA); - (ii) is a preformed metal catalyst, which contains at least one transition metal selected from Ru, Rh, Pd, Ir, Ni, Pt, Au and at least one chiral ligand selected from phosphino, amino and/or amino-phosphino species, preferably DIOP, BINAP Monophos or TMBTP. |