改性HZSM-5分子筛上噻吩烷基化反应和失活再生性能的研究

采用不同碱单独处理和两种碱不同方式联合处理HZSM-5分子筛，制备微孔-介孔多级孔HZSM-5分子筛催化剂并应用于噻吩烷基化反应中。结果表明，不同碱单独处理和两种碱不同方式联合处理HZSM-5分子筛后，均能够在分子筛上造出介孔孔道且能够调变分子筛的酸性，其中，采用Na₂CO₃溶液和TPAOH溶液分开处理得到的分子筛催化剂织结构最适合噻吩烷基化反应；其次考察具有最佳织结构分子筛催化剂的噻吩烷基化反应稳定性，并分析催化剂失活的原因和再生条件。结果表明，当噻吩烷基化反应进行到1050 h后，催化剂已基本失活，催化剂失活的主要原因是，在反应过程中原料中反应组分间发生烯烃齐聚、环化、脱氢和芳烃烷基化等副反应生成的大分子化合物沉积在催化剂上，堵塞催化剂的孔道和遮盖催化剂的活性中心所致；对失活催化剂进行高温再生，从高温再生的能耗较大以及多次高温再生对催化剂酸性和骨架结构不利的角度考虑，选定催化剂的再生温度为550 ℃。

Study on the alkylation of thiophene and catalyst deactivation and regeneration with modified HZSM-5 zeolite

HZSM-5 zeolites were treated by different alkalis alone or different combining ways with two kind of alkalis to prepare micro-meso hierarchical pore HZSM-5 catalysts for thiophene alkylation reaction. The result show that mesopores are created in molecular sieves and the acidity of catalysts after treated is modulated by single alkali or different combining methods of double alkalis. Simultaneously, the structure of catalyst obtained by the separate treatment of Na₂CO₃ solution and TPAOH solution is most suitable for the thiophene alkylation reaction. Furthermore, the stability of the thiophene alkylation reaction over the catalyst with the best microstructure was investigated, and the reason of catalyst deactivation and the regeneration conditions were determined. The results show that the catalysts are basically inactivated after thiophene alkylation reaction for 1050 h. During the reaction, the macromolecular compounds such as olefin oligomerization formed by the cyclization, dehydrogenation and aromatics alkylation are deposited on the catalyst, blocking the pore and then covering the active site of the catalyst. From the viewpoint of the high energy consumption in regeneration at high temperature and the adverse effect of repeated high temperature regeneration on the acidity and skeleton structure of the catalyst, the catalyst should be regenerated at the temperature of 550℃.