Cr-Zn-Al催化剂气相氟化法合成HFC-134a

Cr-Zn-Al Catalyst for Synthesizing HFC-134a by Gas Phase Fluorination

用共沉淀法制备了Cr-Zn-Al型催化剂，用于催化1，1，1-三氟-2-氯乙烷（HCFC-133a）与HF的反应，制备了1，1，1，2-四氟乙烷（HFC-134a）。BET法表征了催化剂的比表面积；GC-MS方法分析了不同反应条件下HCFC-133a的转化率、HFC-134a的收率、以及副产物组成。结果表明，催化剂按一定程序烧结、活化后，反应温度为350～370℃，n（HF）／n（HCFC-133a）=8～12时，HFC-134a的收率为30％～38％，反应产物中HFC-134a的选择性大于99％。连续反应720h后，催化剂的活性不变。

Co-precipitation technique is employed to prepare a Cr-Zn-Al catalyst, Whereby 1,1,1- trifluoro-2-chloroethane （HCFC-133a） reacted with HF to synthesize 1,1,1,2-tetrafluoroethane （ HFC- 134a）. BET nitrogen absorption method is used to analyze surface area of the catalyst. GC-MS is employed to investigate conversion of HCFC-133a, selectivity for HFC-134a and composition of by- products under various conditions. The results show that the Cr-Zn,Al catalyst, after programmed sintering and activating steps, exhibits high catalytic activity： high yield of HFC-134a （30%-38% ） and superior selectivity for HFC-134a （above 99% ） when the temperature is set between 350℃ and 370℃ and mole ratio of HF to HCFC-133a ranges from 8 to 12. The original catalytic activity remains unchanged after 720 hour reaction.