纳米薄层MCM-22分子筛合成及其三甲苯异构化催化性能  

Nano-thin layer MCM-22 zeolite:Synthesis and catalytic properties of trimethylbenzene isomerization reaction

作　　者：高玉芳[1] 侯楠 梁亚凝 李宁 张燕挺 李泽龙 李晓峰[2] GAO Yufang;HOU Nan;LIANG Yaning;LI Ning;ZHANG Yanting;LI Zelong;LI Xiaofeng(School of Chemistry,Taiyuan University of Technology,Taiyuan 030024,China;School of Chemical Engineering and Technology,Taiyuan University of Technology,Taiyuan 030024,China;Sinopec Catalyst Corporation,Beijing 100864,China)

机构地区：[1]太原理工大学化学学院,太原030024 [2]太原理工大学化学工程与技术学院,太原030024 [3]中国石化催化剂有限公司,北京102400

出　　处：《无机化学学报》2024年第6期1079-1087,共9页Chinese Journal of Inorganic Chemistry

摘　　要：采用十六烷基三甲基溴化铵(CTAB)和六亚甲基亚胺(HMI)组成双模板体系,以气相二氧化硅为硅源,在150℃下动态原位合成了薄层的MWW型MCM-22分子筛纳米片,并考察了CTAB添加量对分子筛产物的影响。采用粉末X射线衍射(PXRD)、扫描电子显微镜(SEM)、N_(2)吸附-脱附、氨气程序升温脱附(NH3-TPD)、高倍透射电子显微镜(HRTEM)、吡啶红外(Py-IR)和2,6-二叔丁基吡啶红外(DTBPy-IR)测试方法对合成的分子筛样品进行表征。结果表明:采用双模板体系可以制备出5~10 nm的薄层MWW型纳米片。同时,通过偏三甲苯异构化反应对样品的催化性能进行了表征,催化结果显示样品d-MWW-4%CTAB具有较好的催化性能,其中偏三甲苯的质量转化率、均三甲苯质量收率及均三甲苯选择性分别为34.97%、22.42%和64.09%,这主要归因于薄层纳米片MCM-22具有的较大外表面积和片层间形成的晶间介孔结构。A nano-thin layer MWW-type zeolite,derived from fumed silica,was dynamically in-situ synthesized at 150℃using a dual-template system of cetyltrimethylammonium bromide(CTAB)and hexamethylene imine(HMI).The effect of CTAB amount on the zeolite was also investigated.The nano-thin layer samples were characterized using powder X-ray diffraction(PXRD),scanning electron microscopy(SEM),N_(2) adsorption-desorption,ammonia temperature programmed desorption(NH3-TPD),high-resolution transmission electron microscopy(HRTEM),pyri-dine infrared spectroscopy(Py-IR),and 2,6-di-tert-butylpyridine infrared spectroscopy(DTBPy-IR).The results indicated that MWW nanosheets with a thickness of 5-10 nm can be prepared using the double template system.Furthermore,the catalytic performance of the samples was evaluated through the isomerization of the trimethylben-zenes reaction.The catalytic results show that the sample d-MWW-4%CTAB exhibits good catalytic performance,with the conversion of 1,2,4-trimethylbenzene,the yield of 1,3,5-trimethylbenzene,and the selectivity of 1,3,5-trimethylbenzene being 34.97%,22.42%,and 64.09%,respectively.This is primarily attributed to the external sur-face area and interlayer mesoporous structure formed in the nano-thin layer MCM-22.

关 键 词：双模板 MWW型纳米片 原位合成 异构化 

分 类 号：O643[理学—物理化学] TQ426[理学—化学]