L沸石的合成条件与反应性能研究

Synthesis,Characterization and Catalytic Property of the L Zeolite

采用水热合成法成功合成了L沸石分子筛。采用X射线衍射仪、红外光谱仪等对其结构进行了表征,并在固定床装置上评价了其芳构化、异构化性能。结果表明,在L沸石合成初始凝胶组成为:n(K2O)/n(Na2O)/n(Al2O3)/n(SiO2)/n(H2O)=5.4∶5.7∶1∶30∶500时,最佳合成条件为:晶化温度170℃,晶化时间24h,陈化温度25℃,陈化时间2h,pH为9～10;该条件下制备的L沸石结晶度更高、骨架结构完整,并且在反应温度为460℃时液体收率达60.5%,异戊烷选择性35%。

The zeolite L was prepared with hydrothermal synthesis method.Synthesized zeolite L samples were characterized by XRD and IR,the performance of L catalysts for the aromatization and isomerization were assessed in a fixed-bed microreactor by using n-pentane as the feedstock.The results indicate that,at the condition of the optimal molar composition of the precursor gel is n（K2O）/n（Na2O）/ n（Al2O3）/ n（SiO 2）/ n（H2O） =5.4∶5.7∶1∶30∶500,the optimum conditions to get phase pure zeolite L with good crystallinity were found to be the pH value of 9～10,the crystallization temperature of 170℃,the crystallization time of 24h,the aging temperature of 25 ℃ and the aging time of 2h.The results show that higher aromatization and isomerization catalytic activity and the yield of liquid product is 60.5%,the selectivity of isopentane is 35%.