The Selective Epoxidation of Propylene over Nad-modified Cu-SiO_2 Catalysts Using Molecular Oxygen as the Oxidant

摘要

Propylene oxide (PO) is one of the most important chemical feedstocks for making polyurethane, unsaturated resins, surfactant, and other products. There are two industrial processes for PO production: the chlorohydrin and the Halcon processes. The former generates chlorinated wastes which give rise to serious problems of environmental pollution; The latter needs heavy capital investment and generates a large amount of the organic co-products. Now numerous efforts have been made in searching for an alternative method for these conventional processes. Up to now, most current researches have focused on three routes. The first is to generate PO from C_3H_6 and H_2O_2 over TS-1 catalysts; the second is to generate PO from C_3H_6 and H_2O_2 produced in situ using O_2 and H_2 over noble metal catalysts such as Au catalysts; the third is to generate PO from C_3H_6 and O_2 over metal catalysts such as Ag and Cu catalysts. The former two routes basically use H_2O_2 as the oxidant, the third route directly uses O_2 as the oxidant and has been highly desirable. In this paper, we report our results for the epoxidation of propylene over NaCl-Modified Cu-SiO_2 catalyst using molecular oxygen as the oxidant.