Study on WO_3/M_xO_y catalyst for dehydration of cyclohexanol to cyclohexene

WO3/SiO2,WO3/γ-Al2O3 and WO3/TiO2 catalysts with 12%wt WO3 content were prepared by the impregnation method,using SiO2,γ-Al2O3 and TiO2 respectively as the support and ammonium metatungstate as the precursor.Catalytic behaviors of the catalysts for dehydration of cyclohexanol to cyclohexene were tested in a fixed bed reactor.The catalysts were characterized by XRD,N2 adsorption,NH3-TPD and CO2-TPD.The results indicated that larger average pore diameter favored internal diffusion of cyclohexanol and cyclohexene and consequently increased conversion of cyclohexanol and selectivity to cyclohexene.More acid sites favored dehydration reaction and conversion of cyclohexanol.Higher surface base strength and more base sites inhibited coke formation and hence improved the catalytic stability.Cyclohexanol conversion of and selectivity to cyclohexene of 100% and 97%,respectively,were attained over 12%WO3/TiO2 catalyst at LHSV of 2.7 h-1 and 170 ℃.