摘要
多级孔ZSM-5分子筛可在保持良好择形催化性能的条件下改善产物的扩散性能,提高反应的选择性。采用浸渍法对分子筛进行金属改性,可有效地减少其Brosted酸量,提高烯烃芳构化反应的选择性。本文采用浸渍法对Si/Al为20(原子比)的多级孔纳米ZSM-5分子筛样品(HiNZ5)进行Ga沉积改性,通过Py-IR、N_2物理吸附等手段对其结构和酸性进行了表征,并以己烯-1为模型化合物对改性前后的样品进行催化芳构化的反应性能评价。改性后多级孔ZSM-5分子筛的B酸量随着Ga含量的增加而降低,B/L值减小,有利于两种酸性位的协同催化,在催化己烯-1芳构化反应中苯、甲苯、二甲苯(BTX)的收率显著提高。
Hierarchical ZSM-5 zeolite has good shape-selective catalytic effect and can also improve the diffusibility as well as selectivity for the objective product. Ga modification hierarchical ZSM-5 zeolites prepared by impregnation method showed lower Br?nsted acidic sites density and higher BTX yield in the aromatization of 1-hexene due to the improvement of synergy catalysis between the Br?nsted and Lewis acidic sites.
引文
[1]Kazansky V.B.,Subbotina I.R.,Santen R.A.,et al.Journal of Catalysis.2004,2:263-269.