水蒸气处理改性的SAPO-11分子筛催化合成2,6-二甲基萘的研究

采用水蒸气对SAPO-11分子筛进行改性.通过XRD、SEM、NH3-TPD以及N2吸脱附等表征手段对改性前后SAPO-11分子筛的结构、酸性进行表征,并研究了改性后分子筛催化合成2,6-二甲基萘反应性能的影响规律.结果表明,水蒸气处理使SAPO-11分子筛发生骨架脱铝,酸中心数量减少,比表面积和孔体积有所下降,从而使2,6-二甲基萘的选择性、2,6-二甲基萘与2,7-二甲基萘的比值及催化稳定性提高.

Study on Catalytic Synthesis of 2, 6-dimethylnaphthalene over SAPO-11 Zeolites Modified by Steam

In this paper, SAPO-11 zeolite catalyst has been treated with steam. The structure and acid property of SAPO-11 before and after modification were characterized by XRD, SEM, NH3-TPD and N2 absorption-desorption, and the influence of the catalytic performance of SAPO-11 zeolite modified on the synthesis of 2,6-dimethylnaphthalene (2,6-DMN) was also studied. Results show that after steam treatment, some of Al was removed from the framework of zeolite, the amount of acidic sites were decreased, surface area and pore volume were reduced. As a result, 2,6-DMN selectivity, the ratio of 2,6-DMN to 2,7-DMN and catalytic stability of SAPO-11 zeolite catalyst increased significantly.