Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (5): 1017-1026.doi: 10.3866/PKU.WHXB201702082

• ARTICLE • Previous Articles     Next Articles

Gas Phase Dehydrochlorination of 1, 1, 2-Trichloroethane over Zn/SiO2 Catalysts: Acidity and Deactivation

Yi-Hao HU,Tong-Yang SONG,Yue-Juan WANG,Geng-Sheng HU,Guan-Qun XIE*(),Meng-Fei LUO*()   

  • Received:2016-11-25 Published:2017-04-20
  • Contact: Guan-Qun XIE,Meng-Fei LUO E-mail:gqxie@zjnu.edu.cn;mengfeiluo@zjnu.edu.cn
  • Supported by:
    the Natural Science Foundation of Zhejiang Province, China(LY16B070001)

Abstract:

A series of SiO2-supported fourth period transition metal catalysts (M/SiO2) was prepared by a wetness impregnation method for the dehydrochlorination of 1, 1, 2-trichloroethane (TCE) in the gas phase. Among these M/SiO2 catalysts, Zn/SiO2 had the best catalytic activity with the highest TCE conversion (~98%) and excellent selectivity for cis-1, 2-dichloroethylene (82%). By increasing the zinc loading, the conversion of TCE using the Zn/SiO2 catalyst was gradually improved, in agreement with the total acidity in the Zn/SiO2 catalyst. Associating the specific activity and specific acidity of the Zn/SiO2 catalyst with different Zn loadings, it was found that higher specific acidity contributed to higher specific activity, indicating that the acid center of Zn/SiO2 was the catalytic active site for the dehydrochlorination of TCE. In the process of dehydrochlorination, the Zn/SiO2 catalyst could be deactivated, mainly due to coke deposition on the catalyst surface. Catalysts with low Zn loading had stronger acid sites, which resulted in more coke formation on the catalyst. The results showed that strong acid sites on the catalyst surface were responsible for the deposition of coke and deactivation of the catalyst.

Key words: Transition metal catalysts, 1, 1, 2-Trichloroethane, Cis-1, 2-dichloroethylene, Dehydrochlorination, Acidity, Deactivation

MSC2000: 

  • O643