Adsorption-assisted catalysts

Abstract

Possibilities for enhancement of catalytic reaction rate by combining adsorptive (unfunctionalized) and catalytically active (functionalized) domains within the polymer skeleton of ion-exchanger catalysts have been studied. These catalysts were prepared by copolymerization of styrene and divinylbenzene with a functionalized monomer (styrene sulfochloride). For comparison were included also catalysts prepared by partial sulfonation of macroreticular copolymers of styrene and divinylbenzene and conventional, fully sulfonated ion exchangers. Catalytic activity was tested by the measurements of initial reaction rates of hydrolysis of ethyl acetate (5 wt% in water, 60°C) and ethyl benzoate (0.035 wt%, 75°C). With the catalysts prepared by copolymerization of the functionalized and unfunctionalized monomers the reaction rate per equivalent of the acid centers was found to be up to 15-times higher than with conventional ion-exchanger catalysts. With the partially sulfonated resins, this effect was somewhat lower, due to less advantageous distribution of the functionalized and unfunctionalized domains.