沸石载体结构对甲烷无氧芳构化性能的影响

考察了担载MoO₃的沸石催化剂上甲烷的无氧芳构化性能,并与沸石结构相关联.结果表明,孔径与苯分子动态直径相当的ZSM-5、ZSM-8、ZSM-11和β沸石等是甲烷无氧芳构化催化剂的良好载体,其中3%MoO₃/HZSM-11具有最高的甲烷芳构化活性和稳定性,973K下的转化率和苯选择性分别为8.0%和90.9%;6%MoO₃/HZSM-8与7%MoO₃/H-β芳构化性能相当.以HMCM-41和HSAPO-34为载体时芳构化活性很低,以HMOR、HX和HY为载体时仅有少量乙烯生成,而以HSAPO-5和HSAPO-11为载体时未检测到烃类生成.

Effects of Zeolite Structure on the Catalytic Performance of Catalysts for Methane Non-oxidative Aromatization

The catalytic performance for methane aromatization in the absence of oxygen over various supported zeolite catalysts was studied on a continuous flow fixed bed reactor. It is found that H-form silica-alumina zeolites with two dimensional space structure, such as ZSM-5, ZSM-8 and ZSM-11 whose pore size is very near to the dynamic diameter of benzene (06 nm), are fine supports for methane aromatization, among which 3%MoO₃/HZSM-11 possesed the highest activity and stability, the maximum conversion of methane and selectivity to benzene are 8.0% and 90.9% respectively. The catalytic performance of MoO₃/HZSM-8 and 3%MoO₃/H-β are relatively lower than that of 3%MoO₃/ HZSM-5. The catalysts supported on HMCM-41 and HSAPO-34 have a very low activity for the reaction and over the catalysts of MoO₃/HMOR, HX and HY only a small amount of ethylene is produced, while hydrocarbons have not been detected over the catalysts of MoO₃/HSAPO-5 and MoO₃/HSAPO-11.