制备条件对AlF_3催化1,1,1,2-四氟乙烷脱氟化氢性能的影响

Effect of Preparation Conditions on Catalytic Performance of AlF_3 Used for Dehydrofluoration of 1,1,1,2-tetrafluoroethane

为了制备具有工业化应用价值的1,1,1,2-四氟乙烷脱氟化氢制备三氟乙烯用催化剂,在固定床反应器上考察了催化剂制备条件如溶剂、沉淀温度、沉淀剂浓度对氟化铝基催化剂性能的影响。结果表明不同制备条件下得到的催化剂均为β-AlF3。当乙醇为溶剂、室温沉淀、氢氟酸浓度为22.5 mol/L时,制得的AlF3催化剂初始活性最高。在反应温度450℃,接触时间3.2(g·s)/mL的条件下,1,1,1,2-四氟乙烷初始转化率达36%,三氟乙烯选择性为100%,运行8 h后催化剂活性保持在26%,选择性为100%。

The AlF3 catalyst was prepared by the precipitator method to catalyze dehydrofluorination of 1,1,1,2-tetrafluoroethane to trifluoroethylene in the fixed-bed reactor. The effects of preparation conditions on catalyst performance were discussed, including solvent, precipitation temperature and the concentration of hydrofluoric acid. It was concluded that the all catalysts were the β-AlF3 without regard to preparation conditions. The AlF3, prepared under ethanol as solvent, room temperature and hydrofluoric acid（22.5 mol/L）, showed the highest initial activity. Over the catalyst, the initial conversion of 1,1,1,2-tetrafluoroethane reached to 36% with the selectivity of trifluoroethylene about 100% at 450 ℃, contact time 3.2 （g·s）/mL. After 8 h reaction, the conversion decreased to 26% and the selectivity was still 100%.