Abstract: A series of CuCl2-KCl catalysts supported on MgO-modified γ-Al2O3 were prepared by the impregnation method.X-raypowder diffraction (XRD), N2 physical adsorption, NH3-temperature-programmed desorption (TPD), and temperature-programmed reduction (TPR) techniques were employed to characterize the structure, the acidity, the reduction and oxidation properties of the catalysts, respectively. The catalytic performance of CuCl2-KCl/MgO-Al2O3 catalysts was evaluated for the oxychlorination of ethane to produce vinyl chloride. XRD results indicate that impregnation of γ-Al2O3 with Mg(NO3)2 forms surface MgAl2O4 spinel on the support. TPR results show that the formation of MgAl2O4 strengthens the interaction between Cu species and the support and promotes the reduction of CuⅡto CuⅠ. The catalytic results reveal that the conversion of ethane and the selectivity for vinyl chloride increase with increasing MgO content, and the highest vinyl chloride selectivity (49.1%) is obtained over the CuCl2-KCl/MgO-Al2O3 catalyst with 10% MgO loading. NH3-TPD results indicate that the surface MgAl2O4 neutralizes strong acid sites of the γ-Al2O3 support and increases the number of weak acid sites, and this is the main reason for the increase of vinyl chloride selectivity.

Key words: ethane, oxychlorination, vinyl chloride, copper chloride, magnesium, aluminum, spinel, modification