在金属络合物和四丁基溴化铵共模板体系下合成Fe-MFI介孔沸石  

Synthesis of Fe-MFI Mesoporous Zeolites in Metal Complex and TBABr Co-Templates System

作　　者：李玉平[1] 周升[2] 杨冬花[3] 李晓峰[3] 潘瑞丽[3] 窦涛[2,3] 

机构地区：[1]太原理工大学材料科学与工程学院,山西太原030024 [2]中国石油大学化工学院,北京102249 [3]太原理工大学精细化工研究所,山西太原030024

出　　处：《石油学报（石油加工）》2013年第6期952-958,共7页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：国家自然科学基金项目(20973123);国家重点基础研究发展计划"973"项目(2012CB215002);山西省基础研究项目(2012011005-7)资助

摘　　要：以金属络合物和四丁基溴化铵共同作模板合成介孔Fe-MFI沸石,考察了不同n(Fe)/n(Si)对合成产物的影响。采用XRD、N2吸附-脱附、FT-IR、SEM、HRTEM、NH3-TPD,UV-vis和XAFS等手段对产物进行表征,并将其用于甲醇制烯烃反应(MTO),评价其催化性能。结果表明,合成体系中加入金属络合物可以合成骨架含Fe的介孔MFI沸石晶体,但结晶度有所下降,且当Fe含量较高时也会有Fe氧化物纳米颗粒分散于沸石晶体表面。介孔的产生是由于EDTA与金属硝酸铁形成的络合物模板剂同时又是孔道结构的导向剂。在催化MTO反应中,与不含Fe的MFI沸石相比,采用介孔Fe-MFI沸石作为催化剂,低碳烯烃(乙烯+丙烯)选择性高,催化稳定性也较好。原因是,一方面适量Fe的加入调变了沸石的酸性及孔道结构;另一方面介孔的引入可以降低扩散阻力,减少副反应的发生和减缓结焦。Fe-MFI mesoporous zeolites were synthesized with metal complex and TBABr as co-templates, and characterized by XRD, FT-IR, N2 adsorption-desorption, SEM, HRTEM, NH3-TPD, UV-vis and XAFS. The influence of n（Fe）/n（Si） on the products was discussed. The catalytic performance of the synthesized catalyst in methanol to olefins（MTO）reaction was investigated. The results showed that mesoporous MFI zeolite containing Fe in the framework could be synthesized with metal complex as co-template, while the degree of crystallization was decreased and nano Fe oxides might also be dispersed on the surface of mesoporous MFI zeolite with higher Fe amount. The formation of mesopore in zeolite was due to that the metal complex from EDTA and ferric nitrate was the pore structure directing agent, simultaneously. The product distribution of MTO catalytic reaction were different when the FeMFI catalyst synthesized under varying n（Fe）/n（Si）.Compared with MFI zeolite, the mesoporous Fe-MFI zeolite showed improved selectivity for C2H4 and C3H6 and catalytic stability, which might be attributed to the adjustment of the acidity and pore structure of Fe-MFI zeolites and the reduction of diffusion resistance, side effects and coke in the presence of mesopores.

关 键 词：介孔 沸石 FE-MFI 模板 甲醇制烯烃(MTO)反应 

分 类 号：O643.36[理学—物理化学]