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Study on ZnF2/Al2O3 catalysts for the vapor phase hydrofluorination of tetrachloroethylene

CHENG Yongxiang,XIE Zunyun,PENG Xiaobo,LUO Mengfei   

  1. Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004, Zhejiang, China
  • Online:2012-11-07 Published:2012-11-05

气相氟化四氯乙烯的ZnF2/Al2O3催化剂

程永香,谢遵运,彭小波,罗孟飞   

  1. 浙江师范大学物理化学研究所,先进催化材料教育部重点实验室,浙江 金华 321004

Abstract: ZnF2/Al2O3 catalysts were prepared by an impregnation method. The effect of the Al2O3 support calcination temperature on catalytic performance for the vapor phase hydrofluorination of tetrachloroethylene was studied. The catalysts were characterized by XRD, Raman, NH3-TPD and BET techniques. The results show that ?-Al2O3 started to transform to ?-Al2O3 and α-Al2O3 at 900 ℃. ?-Al2O3 reaches to its maximum at 1100℃. By further increasing the calcination temperature, all ?-Al2O3 transformed to α-Al2O3. The highest activity was obtained on a ZnF2/Al2O3 catalyst with the Al2O3 support calcined at 1110 ℃. The conversion of tetrachloroethylene was 45.7% and the selectivity to HCFC-123 (2,2-dichloro-1,1,1-three ethyl fluoride) and HCFC-124(2-chloro-1,1,1,2- tetrafluoroethane) was 48.2% at a reaction temperature of 300 ℃.

Key words: Al2O3, ZnO, ZnF2, tetrachloroethylene, HCFC-123, HCFC-124

摘要: 采用浸渍法制备了ZnO/Al2O3催化剂,考察了载体Al2O3的焙烧温度对催化剂性能的影响。并对催化剂进行了X射线衍射(XRD)、Raman光谱、氨气程序升温脱附(NH3-TPD)和BET表征。结果表明:随着Al2O3焙烧温度升高,从900 ℃开始,?-Al2O3逐渐向?-Al2O3和α-Al2O3转变,1100 ℃焙烧样品中?-Al2O3的XRD峰强度达到最大。当温度继续升高,?-Al2O3将转变成α-Al2O3。Al2O3载体经过1100 ℃焙烧制得的ZnF2/Al2O3催化剂催化性能最高,当反应温度为300 ℃时,四氯乙烯的转化率为45.7%,HCFC-123(2,2-二氯-1,1,1-三氟乙烷)和HCFC-124(2-氯-1,1,1,2-四氟乙烷)的总选择性为48.2%。

关键词: Al2O3, ZnO, ZnF2, 四氯乙烯, HCFC-123, HCFC-124