ZSM-11和ZSM-5分子筛孔道结构差异对其甲醇制烯烃催化性能的影响  

Effect of framework structure of ZSM-11 and ZSM-5 zeolites on their catalytic performance in the conversion of methanol to olefins

作　　者：原凯 贾翔宇 王森[1] 樊升 何诗沛 王鹏飞 董梅[1] 秦张峰[1] 樊卫斌[1] 王建国 YUAN Kai;JIA Xiang-yu;WANG Sen;FAN Sheng;HE Shi-pei;WANG Peng-fei;DONG Mei;QIN Zhang-feng;FAN Wei-bin;WANG Jian-guo(State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院山西煤炭化学研究所煤转化国家重点实验室,山西太原030001 [2]中国科学院大学,北京100049

出　　处：《燃料化学学报（中英文）》2023年第11期1652-1662,共11页Journal of Fuel Chemistry and Technology

基　　金：国家重点研发计划(2020YFA0210900);国家自然科学基金(U1910203,21991090,21991092,22272195,U22A20431);中国科学院青年创新促进会项目(2021172)资助。

摘　　要：本工作采用水热合成法制备了具有相似形貌、粒径、织构性质和酸性的ZSM-11和ZSM-5分子筛,借助多种表征技术研究了这两类分子筛的十元环孔道结构差异对其甲醇转化制烯烃(MTO)催化性能的影响。结果表明,由于ZSM-5的正弦孔道比ZSM-11的直孔道的扩散阻力大,反应中间体和产物分子在ZSM-5分子筛上的停留时间较长,强化了长链烯烃氢转移反应,导致生成更多的甲基苯物种,从而增强了芳烃循环的贡献;相比之下,ZSM-11分子筛的直孔道限制了长链烯烃的氢转移反应,减少了多甲基苯物种的产生,有利于提高烯烃循环的贡献。因此,与具有相似形貌、粒径、织构性质和酸性的ZSM-5-60分子筛相比,ZSM-11-60分子筛对MTO反应具有更长的催化寿命(98.3 h对比65.4h)和更高的丙烯选择性(34.6%对比27.4%)。这些结果深化了对分子筛MTO催化性能与其孔道结构关系的认识,有助于新型高效的甲醇转化分子筛催化剂的开发和反应过程的探索。The catalytic performance of zeolites is closely related to their framework structure and a clear understanding of such a structure-performance relationship is of great significance in revealing catalytic reaction mechanism as well as in developing efficient zeolite catalysts.Herein,ZSM-11 and ZSM-5 zeolites with similar morphology,crystal size,textural properties and acidity were hydrothermally synthesized;the effects of their differences in the 10-ring channels on the catalytic performance in the conversion of methanol to olefins(MTO)were investigated by using various characterization techniques.The results indicate that in comparison with the straight channel of ZSM-11,the sinusoidal channel of ZSM-5 has stronger diffusion resistance,which promotes the hydrogen-transfer in higher olefins,leads to forming more polymethylbenzene species and then raises the contribution of aromatic-based cycle.In contrast,ZSM-11 with straight channel can reduce the formation of polymethylbenzene species and enhance the alkene-based cycle.As a result,compared with ZSM-5-60 with similar morphology and acidity,ZSM-11-60 as a catalyst in MTO exhibits longer lifetime(98.3 h vs.65.4 h)and higher selectivity to propene(34.6%vs.27.4%).The insight shown in this work helps to have a better understanding of the relation between zeolite structure and catalytic performance in MTO and is then beneficial to the development of better catalysts and processes for MTO.

关 键 词：ZSM-11 ZSM-5 直孔道 正弦孔道 甲醇转化制烯烃 

分 类 号：O643.3[理学—物理化学]