[B,Al]-IM5分子筛的合成及其在甲苯与乙烯烷基化反应中的催化性能  

Synthesis of[B,Al]−IM5 zeolites and their catalytic properties in the alkylation of toluene with ethylene

作　　者：胡湘龙 王永睿 郝书敏 陈俊文 HU XiangLong;WANG YongRui;HAO ShuMin;CHEN JunWen(State Key Laboratory of Petroleum Molecular&Process Engineering,Sinopec Research Institute of Petroleum Processing Co.,Ltd.,Beijing 100083,China)

机构地区：[1]中石化石油化工科学研究院有限公司石油化工分子转化与反应工程全国重点实验室,北京100083

出　　处：《北京化工大学学报（自然科学版）》2024年第6期41-53,共13页Journal of Beijing University of Chemical Technology(Natural Science Edition)

基　　金：中国石油化工股份有限公司技术开发课题(421053)。

摘　　要：采用水热晶化法,以1,5-双(N-甲基吡咯烷)戊烷溴盐(MPPBr_(2))为模板剂,在n(SiO_(2))∶n(Al_(2)O_(3))=40~80的范围内合成了纯相[B,Al]-IM5分子筛。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、荧光光谱仪(XRF)、电感耦合等离子体发射光谱-质谱仪(ICP-MS)、静态氮吸附仪和化学吸附仪等方法对分子筛进行了表征。结果表明,与棒状IM-5分子筛中试样品相比,[B,Al]-IM5分子筛呈片层形貌,XRD峰强度较低,比表面积较大,酸量和B酸量/L酸量较低。在[B,Al]-IM5分子筛的晶化过程中发现,B原子以四配位形式进入分子筛骨架,模板剂的分解量较少,促进了分子筛某方向晶面的生长,出现片层形貌。对于甲苯与乙烯气相烷基化反应,在300℃、n(SiO_(2))∶n(Al_(2)O_(3))=60的条件下,[B,Al]-IM5分子筛的乙烯转化率为97.0%~98.5%,甲苯转化率为12.0%~10.3%,接近理论转化率(12.5%),对-甲乙苯的选择性为41.9%~73.8%,对位选择性为79.1%~85.8%。与ZSM-5相比,[B,Al]-IM5的反应温度较低(300℃),乙烯转化率较高(98.5%),可以稳定运行105 h,较文献报道的改性ZSM-5分子筛和中试IM-5分子筛分别延长了25 h和78 h。Pure phase[B,Al]-IM5 zeolites were synthesized by a hydrothermal crystallization method using 1,5-bis(N-methylpyrrolidine)pentane dibromide(MPPBr_(2))as a template in the range n(SiO_(2))∶n(Al_(2)O_(3))=40-80.The[B,Al]-IM5 zeolites were characterized by X-ray diffractometry(XRD),scanning electron microscope(SEM),fluorescence spectrometry(XRF),inductively coupled plasma emission spectrometry–mass spectrometry(ICP-MS),static nitrogen adsorption measurements,and chemical adsorption measurements.The results show that the[B,Al]-IM5 zeolites have a lamellar morphology,the XRD peak intensity is low,the specific surface area is larger than that of the rod-like pilot-scale IM-5 zeolite,and the acid amount and ratio of B acid to L acid are both low.During the crystallization process of[B,Al]-IM5 zeolites,B atoms enter the molecular sieve framework in a fourcoordinate form,and the decomposition of the template agent reduced,which promotes the growth of the crystal planes in specific directions resulting in the observed lamellar morphology.In the gas-phase alkylation reaction of toluene with ethylene,at a temperature of 300℃ and n(SiO_(2))∶n(Al_(2)O_(3))of 60,the ethylene conversion with[B,Al]-IM5 zeolite was 97.0%-98.5%,the toluene conversion(12.0%-10.3%)was close to the theoretical conversion(12.5%),and the selectivity and para-selectivity of p-methylethylbenzene were 41.9%-73.8%and 79.1%–85.8%,respectively.Compared with ZSM-5,the reaction temperature(300℃)of[B,Al]-IM5 was lower and the conversion of ethylene(98.5%)was higher.The[B,Al]-IM5 zeolites can run stably for 105 h,which is 25 h and 78 h longer than that of the modified ZSM-5 zeolite in the literature and the pilot-scale IM-5 zeolite,respectively.

关 键 词：分子筛 [B Al]-IM5 烷基化 对-甲乙苯 催化性能 

分 类 号：TQ241.1[化学工程—有机化工]