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

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.用等体积浸渍法制备了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.

Synthesis of Hierarchical HZSM-5 Microspheres without Second Template and Their Application in Methane Dehydroaromatization

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 μm were constructed by many rod-shaped crystals.N2 adsorption at-196 oC revealed that the ZSM-5-HW zeolite is of both micropore and mesopore structure.The hierarchical Mo/HZSM-5-HW catalyst 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 24h.