Effect of silylation treatment on the catalytic performance of HMCM-49 in the alkylation of phenol

Abstract

In this paper, chemical vapor deposition (CVD) treatment with silane reagent was used to treat HMCM-49 zeolites to eliminate or deactivate the strong acid sites where byproducts were produced to improve the catalytic performance of HMCM-49 zeolites. The results of the characterization with XRD, SEM, FT-IR, N2 adsorption/desorption, XRF and NH3-TPD show that the CVD treatment can effectively eliminate or deactivate most of the strong Bronsted acid sites on the external surface of HMCM-49 zeolites, and the intensity of acid sites on the surface of zeolites also reduced. As a result, the catalytic performance of HMCM-49 zeolites has improved. But two or more times CVD treatment may cause effective aperture of micro-pore shrunk or the micro-pores partly blocked. The alkylation of phenol with isopropanol not only depends on the acid sites on the surface of zeolites, but also may relate with aperture of micro-pore and the dimensional size around the pore mouths.