纳米Pd/ZSM-5的原位法制备及催化肉桂醛加氢

摘要

Highly dispersed Pd nanoparticles confined in the ZSM-5 zeolite catalyst (Pd/ZSM-5-IS) were successfully synthesized by azeotropic distillation assisted in situ process.The Pd/ZSM-5-IS samples were characterized by XRD,TEM and XPS.The effects of reaction pressure,reaction temperature and reaction time on the catalytic performance of cinnamaldehydē hydrogenation were investigated.These results showed that the catalytic stability of Pd/ZSM-5-IS catalyst is higher than that of Pd/ZSM-5-IM,which is mainly attributed to the fact that Pd nanoparticles enter the mesoporous mesopores of ZSM-5 to effectively prevent the active sites from loss and aggregation.When the reaction temperature is 80 ℃,the reaction pressure is 1 MPa,the reaction time is 3 h for the best reaction conditions,the conversion of cinnamaldehyde was 87.23％ and selectivity of hydrocinnamic aldehyde was 76.68％.%采用共沸精镏辅助的原位法成功合成了高度分散的Pd纳米颗粒负载在ZSM-5中(Pd/ZSM-5-IS)分子筛催化剂.通过XRD 、TEM 、XPS等手段对Pd/ZSM-5-IS的样品进行了表征,并考察反应压力、反应温度、反应时间对肉桂醛加氢催化性能的影响.结果表明:原位法制备的Pd/ZSM-5-IS催化剂比浸渍法制备的Pd/ZSM-5-IM催化剂具有更高的催化稳定性,其主要归因于Pd纳米颗粒进入ZSM-5的晶内介孔有效防止活性位点的损失和聚集.当反应温度为80℃,反应压力为l MPa,反应时间为3h时为最佳反应条件,肉桂醛的转化率为87.23％,苯丙醛的选择性为76.68％.