Mesoporous Silica-Carbon Composite Membranes for Simultaneous Hydrolysis and Separation of Chiral Epoxide

The carbon/porous silica composite membrane was fabricated in a simple manner, which could be successfully for the simulta- neous separation and production of chiral epoxides and 1,2-diols, based on their differences in hydrophilic/hydrophobic natures. The chiral Co(III)-BF3 salen catalyst adopted in the membrane reactor system has given the very high enantiose- lectivity and recyclability in hydrolysis of terminal epoxides such as ECH, 1,2-EB, and SO. The optically pure epoxide and the chiral catalyst were collected in the organic phase after hydrolysis reaction. The hydrophilic water-soluble 1,2-diol product hydrolyzed by chiral salen diffused into the aqueous phase through the SBA-16 or NaY/SBA-16 silica composite layer during the reaction. The water acted simultaneously as a reactant and a solvent in the membrane system. One optical isomer was obtained with high purity and yield, and furthermore the catalysts could be recycled without observable loss in their activity in the continuous flow-type membrane reactor.