无第二模板剂法合成多级结构ZSM-5分子筛微球及其在甲烷无氧芳构化反应中的应用

摘要

Hierarchical ZSM-5(ZSM-5-HW) microspheres were synthesized by controlling the hydrothermal conditions without any secondary template. The ZSM-5-HW microspheres with a diameter range of 10-15 um were constructed by many rod-shaped crystals. N2 adsorption at -196 ℃ revealed that the ZSM-5-HW zeolite is of both micropore and mesopore structure. The hierarchical Mo/HZSM-5-HW catalysl exhibited higher catalytic activity and stability in methane dehydroaromatization. The initial CH4 conversion and the highest benzene yield were 18.5％ and 9.5％, respectively, which are better than that of the conventional Mo/HZSM-5 catalyst. The CH4 conversion and benzene yield was kept at 10.2％ and 5.5％, respectively, after running the reaction for 24 h.%在无第二模板剂的条件下,采用简单的水热晶化法,通过控制条件合成出具有多级结构的ZSM-5(ZSM-5-HW)分子筛,并运用X射线衍射、红外光谱、扫描电镜和N2吸附-脱附等技术对合成的分子筛进行了表征.结果表明,所得样品是由棒状晶体组装而成的具有介孔结构的分子筛微球.用等体秘浸渍法制备了Mo/HZSM-5-HW催化剂并用于CH4无氧芳构化反应,表现出较高的催化活性和稳定性.在实验条件下,CH4初始转化率为18.5%,而苯收率最高可达9.5%;反应24h后,两者仍然分别保持在10.2%和5.5%左右.