【摘要】 钼基分子筛催化剂 ,由于不同分子筛的孔道大小及孔道形状不同 ,对甲烷芳构化反应表现出不同的催化性能 .具有 8元环孔道结构的小孔ERS 7分子筛没有催化活性 ,说明甲烷的芳构化反应离不开分子筛孔道的择形作用 ,较小的孔道中不能生成苯等芳烃 .具有 10元环孔道结构的ZSM 5 ,ZSM 11和ZRP 1三种分子筛具有较好的催化性能 ,但由于其孔道大小及孔道形状的差别在催化行为上表现出一定的差异 .具有 10元环和 12元环孔道结构的MCM 2 2分子筛 ,尤其对苯等轻芳烃而言 ,催化性能最佳 .具有 12元环孔道结构的JQX 1以及中孔分子筛SBA 15 ,虽然具有一定的催化性能 ,但活性较低 .研究结果表明 ,孔道大小与苯分子动态直径相近或孔道稍大的分子筛是催化甲烷芳构化反应的良好载体 ,孔道过大或过小都不利于苯和萘等芳烃的生成更多还原

【Abstract】 The catalytic behavior of Mo based zeolite catalysts with different pore structure and size, particularly with 8 membered ring (MR), 10 MR, coexisted 10 and 12 MR, and 12 MR, was studied in methane aromatization under the conditions of SV= 1?500 ml/(g·h), p =0 1 MPa and T =973 K. It was found that the catalytic performance is correlated with the pore structure of the zeolite supports. The zeolites that possess 10 MR or 10 and 12 MR pore structure with a pore diameter equal to or slightly larger than the dynamic diameter of benzene molecule, such as ZSM 5, ZSM 11, ZRP 1 and MCM 22, are fine supports. Among the tested zeolite supports, MCM 22 exhibits the highest activity and selectivity for benzene. A methane conversion of 10 5% with benzene selectivity of 80% was achieved over Mo/MCM 22 catalyst. The Mo/ERS 7 catalyst with 8 MR (0 45 nm) does not show any activity in methane dehydro aromatization, while Mo/JQX 1 and Mo/SBA 15 catalysts with 12 MR pore exhibit little activity in the reaction. It can be concluded that the zeolites with 10 MR pore or coexisted 10 and 12 MR, having pore size equal to or slightly larger than the dynamic diameter of benzene molecule, are fine supports for methane activation and aromatization.更多还原