原位合成纳米Ga/Al-ZSM-5分子筛及其催化正己烷芳构化反应性能  

In-situ Synthesis of Nano Ga/Al-ZSM-5 Zeolite and Its Catalytic Performance in the n-Hexane Aromatization

作　　者：梁时语 房玉俊 辛晴 李佳芮 白雪峰[1] 吴伟[1] LIANG Shi-yu;FANG Yu-jun;XIN Qing;LI Jia-rui;BAI Xue-feng;WU Wei(International Joint Research Center for Catalytic Technology,College of Chemical and Materials,Heilongjiang University,Harbin 150080,China)

机构地区：[1]黑龙江大学化学化工与材料学院催化技术国际联合研究中心,黑龙江哈尔滨150080

出　　处：《化学与粘合》2021年第3期167-174,共8页Chemistry and Adhesion

基　　金：黑龙江省大学生创新训练计划项目(编号:202010212063)。

摘　　要：具有独特的三维交叉孔道结构和择形催化作用的ZSM-5分子筛是芳构化反应较适宜的催化剂。但是具有微米尺度的硅铝酸盐分子筛较大的晶粒会限制产物的生成和扩散,其较强的酸性还会导致催化剂因积炭而快速失活。为了解决这些问题,采用预制晶种引导法原位合成了Ga部分同晶置换的系列纳米Ga/Al-ZSM-5分子筛催化剂,并通过加入改变介孔模板剂十六烷基三甲基溴化铵(CTAB)用量对分子筛的粒径、酸性及催化反应性能进行精细调变,研究了该系列分子筛的孔道特性、酸性对其催化正己烷芳构化反应性能的影响规律。结果表明,Ga引入分子筛骨架的Ga/Al-ZSM-5纳米分子筛具有温和的酸性,加入适宜量的CTAB可以降低分子筛的酸强度,减少Br?sted酸量,改善己烷芳构化反应性能。Ga/Al-NZ5-0.045CTAB分子筛表现出最佳的正己烷芳构化的反应性能,当正己烷转化率为99.0%时,芳烃和苯、甲苯及二甲苯(BTX)的收率分别高达49.3%和40.1%。The ZSM-5 zeolite is proposed to be a suitable catalyst for aromatization reactions due to its unique interconnected three-dimensional pore structure and shape-selective catalysis.However,the ZSM-5 aluminosilicate with micrometer scale limits the formation and diffusion of the reaction products,and its strong acidity also leads to the rapid deactivation of the catalyst due to carbon deposition.In order to solve these problems,a series of nano Ga/Al-ZSM-5 zeolite modified by Ga partial isomorphous substitution are synthesized by using an in-situ seed-introduced method,and the particle size,acidity and catalytic performance of the Ga-modified zeolites is finely adjusted by changing the addition amount of cetyltrimethylammonium bromide (CTAB)added as mesoporous template.The influence of the pore characteristics and acidity of the series of zeolites on its catalytic performance in the n-hexane aromatization is studied.The results show that the nano Ga/Al-ZSM-5 zeolite in which Ga introduced into the framework has mild acidity.Adding an appropriate amount of CTAB in the initial gel can reduce the acid strength of the synthesized zeolites,the amount of Br?sted acid sites and improve the n-hexane aromatization performance.The Ga/Al-NZ5-0.045CTAB catalyst shows the best performance of the nhexane aromatization,the aromatic and BTX(benzene,toluene and xylene)yield are 49.3%and 40.1%,respectively when the n-hexane conversion is99.0%.

关 键 词：纳米ZSM-5分子筛 Ga同晶置换 芳构化 酸催化 正己烷 

分 类 号：TQ426[化学工程]