A Comparative Study of Methanol to Olefin over CHA and MTF Zeolites
A Comparative Study of Methanol to Olefin over CHA and MTF Zeolites
复制标题
DOI：
10.1021/jp063172c
复制
发表时间：
2007-03
影响因子：
3.7
通讯作者：
Qingjun Zhu;J. Kondo;T. Tatsumi;S. Inagaki;Ryosuke Ohnuma;Y. Kubota;Y. Shimodaira;Hisayoshi Kobayashi;K. Domen
中科院分区：
文献类型：
--
作者：
Qingjun Zhu;J. Kondo;T. Tatsumi;S. Inagaki;Ryosuke Ohnuma;Y. Kubota;Y. Shimodaira;Hisayoshi Kobayashi;K. Domen
合成了H-SSZ-13（CHA）和H-UTM-1（MTF）分子筛，对其进行了表征，并将其用作甲醇制烯烃（MTO）反应的催化剂。这两种沸石都有八元环，它们的结构和酸性通过27 Al魔角旋转（MAS）NMR，NH3−TPD（程序升温脱附）和原位IR光谱表征。原位红外光谱表明，甲醇是有效地激活两种沸石的布朗斯台德酸中心。在673 K时，甲醇在H-SSZ-13上定量转化为烃，主要是乙烯和丙烯，而H-UTM-1最初仅产生少量烯烃，主要产物是二甲醚。建议MTF沸石笼中的有限空间防止中间体多甲基苯的形成，从而也防止烃的形成，而活性的CHA型沸石中的笼尺寸足够大以容纳多甲基苯。
H-SSZ-13 (CHA) and H-UTM-1 (MTF) zeolites have been synthesized, characterized, and employed as catalysts for the methanol-to-olefin (MTO) reaction. Both zeolites have eight-membered rings, and their structures and acidities are characterized by 27Al magic-angle spinning (MAS) NMR, NH3−TPD (temperature-programmed desorption), and in-situ IR spectroscopy. In-situ IR spectroscopy indicates that methanol is efficiently activated on the Bronsted acid sites of both zeolites. At 673 K, the methanol is quantitatively converted to hydrocarbons, mainly ethene and propene, over H-SSZ-13, whereas H-UTM-1 only initially gives a small amount of alkenes, the main product being dimethyl ether. It is proposed that the limited space in the cages of the MTF zeolite prevents formation of intermediate polymethylbenzenes and thereby also formation of hydrocarbons, whereas the cage size in the CHA type zeolite, which is active, is large enough to accommodate polymethylbenzenes.