五氟氯乙烷的钯催化法加氢脱氯反应研究

催化加氢脱氯是有选择性地去除氟里昂(CFCs)分子中对臭氧层有破坏作用的氯原子,将其转化成可能的替代物氢氟烃(HFCs).以活性炭为载体的负载型钯催化剂对五氟氯乙烷的选择性加氢脱氯反应具有良好的催化活性,色谱分析表明,其生成产物五氟乙烷的选择性高达99%.活性炭载体经浓硝酸氧化处理后能明显提高负载型钯催化剂的催化活性和催化稳定性.这归因于载体表面生成了较多的表面含氧官能团,有利于提高载体表面Pd的分散度,影响了催化性能.进一步地动力学研究得出,五氟氯乙烷选择性加氢脱氯反应对H2和五氟氯乙烷的表观反应级数分别为1/4和1/2. 

The Research of Hydrodechlorination Reaction of Chloropentafluoroethane by Palladium Catalysts

The method of hydrodechlorination by palladium catalyst is to remove chlorine atom in chlorofluorocarbon and turn it into the possible substitute pentafluoroethane.The supported palladium on activated carbons was effective catalyst for selective hydrodechlorination of chloropentafluoroethane.The selectiveness to pentafluoroethane reached 99% in hydrodechlorination of chloropentafluoroethane.The catalytic stability and activity of supported palladium in hydrodechlorination were improved when the activated carbon supports were pretreated with concentrated nitric acid.These improvements attributed to the formation of finely dispersed palladium particles.The apparent reaction orders of H2 and chloropentafluoroethane for hydrodechlorination of chloropentafluoroethane were respectively 1/4 and 1/2.