改性纳米ZSM-5分子筛催化甲醇制对二甲苯的反应性能  

Study on Catalytic Performance of Methanol to p-Xylene over Modified Nano-sized ZSM-5 Zeolites

作　　者：张娇玉 朱生华 唐瑞源 郑延成[1] 李克华[1] ZHANG Jiaoyu;ZHU Shenghua;TANG Ruiyuan;ZHENG Yancheng;LI Kehua(College of Chemistry and Environmental Engineering,Yangtze University,Jingzhou,Hubei 434000,China;Research Center of Petroleum Processing&Petrochemicals,Xi’an Shiyou University,Xi’an,Shaanxi 710065,China)

机构地区：[1]长江大学化学与环境工程学院,湖北荆州434000 [2]西安石油大学石油炼化工程技术研究中心,陕西西安710065

出　　处：《西安石油大学学报（自然科学版）》2024年第5期109-115,126,共8页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：重质油国家重点实验室开放课题项目(SKLOP201901001);湖北省教育厅指导性项目(B2020040);省部共建煤炭高效利用与绿色化工国家重点实验室开放课题(2021-K44)。

摘　　要：通过水热合成的方法合成纳米ZSM-5分子筛,并采用等体积浸渍法制备ZnO,MgO和P_(2)O_(5)复合改性分子筛,用于催化甲醇高选择性制对二甲苯反应中。采用XRD、SEM、氮气吸附-脱附以及NH_(3)-TPD等手段对催化剂进行表征分析,并在固定床微型反应装置上进行甲醇直接制对二甲苯(MTPX)反应性能评价。结果表明:相比于常规微米ZSM-5分子筛,纳米分子筛具有大量晶间介孔,提高总芳烃选择性;Zn改性减少强酸量,增加中强酸酸量,有利于芳烃产物的生成;分子筛上进一步引入适量的MgO和P_(2)O_(5)可以有效覆盖分子筛的部分孔口和外表面的酸性位,对孔道扩散限制产生影响,对位选择性提高至81.1%,对二甲苯选择性提高至23.3%。Nano ZSM-5 zeolites was synthesized by hydrothermal synthesis method,and the compositely modified nano ZSM-5zeolites by ZnO,MgO,and P_(2)O_(5) was prepared by equal volume impregnation method,which was used to catalyze the highly selective reaction of preparing p-xylene using methanol.The synthesized modified nano-sized ZSM-5 zeolites was characterized by XRD,SEM,N_(2) adsorption-desorption and NH_(3)-TPD.Furthermore,the catalytic performance of different ZSM-5 zeolites for using methanol to prepare p-xylene was investigated.The results indicated that,nano-sized samples exhibited higher aromatic selectivity than micro-sized ZSM-5,owing to the more inter-mesopores.The introduction of Zn could increase the medium acid sites,which enhanced the aromatic production.The modification of Mg and P could optimise both the acidic properties and shape selectivity,which is beneficial to the formation of p-xylene.The modified nano-sized ZSM-5 zeolite gave the p-xylene selectivity of 23.3%,with the para-selectivity of 81.1%.

关 键 词：纳米ZSM-5分子筛 复合改性 对二甲苯 甲醇 择形性 

分 类 号：TE65[石油与天然气工程—油气加工工程] TQ241[化学工程—有机化工]