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Hierarchical porous MCM-68 zeolites: Synthesis, characterization and catalytic performance in m-xylene isomerization
Microporous and Mesoporous Materials ( IF 4.8 ) Pub Date : 2017-12-11 , DOI: 10.1016/j.micromeso.2017.12.009
He Hao , Yue Chang , Wenjun Yu , Lan-Lan Lou , Shuangxi Liu

Novel hierarchical MCM-68 zeolite materials were successfully prepared by two simple, effective and environmentally friendly methods: H2O2 microexplosion under microwave and NH3(aq) treatment. The characterization of the materials with powder XRD, SEM, TEM, N2-sorption, and NH3-TPD proved that abundant mesopores across zeolite crystals were created while the microporous MSE framework was well preserved. The mesopore volume of hierarchical MCM-68 zeolites is up to 0.19 cm3 g−1. The crystallinities of hierarchical ones and microporous MCM-68 are nearly the same according to the XRD result. The acidities of hierarchical MCM-68 are generally lower than their raw materials. Gas-phase isomerization reaction of m-xylene was carried out over these hierarchical MCM-68 zeolites as well as HMCM-68 zeolite under different conditions to characterize the catalytic property of newly prepared hierarchical zeolites. It was found that the m-xylene conversion and disproportionation/isomerization rate ratio were closely related to the created mesopores in hierarchical MCM-68 zeolites under high reaction temperature and low weight hourly space velocity (WHSV). Moreover, these hierarchical MCM-68 zeolites exhibited improved resistance to coke formation compared with HMCM-68.



中文翻译:

分级多孔MCM-68沸石:合成,表征和在催化性能二甲苯异构化

通过两种简单,有效和环境友好的方法成功制备了新型的分层MCM-68沸石材料:微波下的H 2 O 2微爆炸和NH 3(aq)处理。用粉末XRD,SEM,TEM,N 2吸附和NH 3 -TPD对材料进行表征,证明在沸石晶体上形成了丰富的中孔,同时很好地保留了微孔MSE骨架。MCM-68分子筛的介孔体积最大为0.19 cm 3  g -1。根据XRD结果,分层晶体和微孔MCM-68的结晶度几乎相同。分级MCM-68的酸度通常低于其原料。的气相异构化反应二甲苯进行超过这些分层MCM-68的沸石,以及在不同条件下HMCM-68沸石以表征新制备分层沸石的催化性能。据发现,所述二甲苯转化率和歧化/异构化率比有密切的关系在高反应温度和低的重时空速(WHSV)下分层MCM-68沸石所创建的中孔。而且,与HMCM-68相比,这些分级的MCM-68沸石显示出对焦炭形成的改进的抵抗性。

更新日期:2017-12-11
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