Selective oxidation of olefins over transition metal-exchanged zeolite Y

Abstract

The selective oxidation of olefins including oxidative dehydrogenation and epoxidation reactions over transition metal-exchanged zeolite. Y at mild reaction conditions was investigated. This dissertation describes the catalytic role of dioxygen adducts of cobalt(II)-ethylenediamine complexes in zeolite Y for oxidative dehydrogenation of 1 ,4-cyclohexadiene, as well as the catalytic properties of molybdenum zeolites in epoxidation reaction of cyclonexene. Since the latter catalyst is novel, considerable attention has been devoted to the preparation and characterization of molybdenum-exchanged zeolites. Bis(ethylenediamine)cobalt(II) forms dioxygen adducts in zeolite Y which are catalytic intermediates in the oxidative dehydrogenation of 1,4-cyclohexadiene to form benzene and water. The intrazeolitic reaction occurred at 25°C; however, diffusion of the products out of the zeolite was very slow at this temperature. At ca. 65°C steady state reaction rates were determined under flow conditions, and it was observed that the reaction rate was first order with respect to the concentration of cobalt-dioxygen complex and zero order with respect to the oxygen partial pressure. Moreover, the reaction rate was first order in cyclohexadiene partial pressure...