Hexane cracking catalyzed by MSE-type zeolite as a solid acid catalyst
Hexane cracking catalyzed by MSE-type zeolite as a solid acid catalyst
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DOI：
10.1016/j.cattod.2013.10.032
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发表时间：
2014-05-01
期刊：
影响因子：
5.3
通讯作者：
Takechi, Kazuyoshi
中科院分区：
文献类型：
--
作者：
Kubota, Yoshihiro;Inagaki, Satoshi;Takechi, Kazuyoshi
以具有三维12-10-10环孔道结构的MCM-68（MSE拓扑结构）为研究对象，期待其具有ZSM-5（MFI拓扑结构）和β（β-ZSM拓扑结构）的杂化特征，作为正己烷裂解反应的固体酸催化剂。没有脱铝的质子形式的MCM-68（具有约12的Si/Al比）在反应期间由于重质焦炭形成而迅速失活，而脱铝的MCM-68在450至600 ℃的反应温度下对己烷裂化表现出足够的催化活性和对焦炭形成的耐久性。在450 - 600 ℃的反应温度下，脱铝的MCM-68与其它沸石催化剂如ZSM-5、丝光沸石和β沸石相比也具有45-50%的更高丙烯选择性。脱铝前后的MCM-68催化剂在600 ℃下反应后再生，表现出与初始催化剂几乎相同的性能。在较高的反应温度如650 ° C下，催化剂主要由于再次形成焦炭而迅速失活。为了避免这种失活，改性的MCM-68与氧化镧简单的浸渍进行。镧改性主要是使催化剂外表面的活性中心失活，从而避免重质焦炭的生成，保持催化剂的活性和丙烯选择性。(C)2013 Elsevier B. V.保留所有权利。
MCM-68 (MSE topology) with three-dimensional 12-10-10-ring channel system was focused on, expecting the hybrid character of ZSM-5 (MFI topology) and beta (*BEA topology), as a solid acid catalyst for hexane cracking reaction. The proton form of MCM-68 without dealumination having Si/Al ratio around 12 was deactivated rapidly during the reaction due to heavy coke formation, whereas dealuminated MCM-68 exhibited sufficient catalytic activity and durability to coke formation for hexane cracking at the reaction temperatures from 450 to 600 degrees C. The dealuminated MCM-68 also had higher propylene selectivity of 45-50% in comparison with other zeolite catalysts such as ZSM-5, mordenite and beta at the reaction temperatures of 450 to 600 degrees C. Both the MCM-68 catalysts before and after dealumination were regenerated after the reaction at 600 degrees C to exhibit almost the same performance as the initial catalyst. At higher reaction temperature such as 650 degrees C, the catalyst was deactivated rapidly mainly due to coke formation again. In order to avoid this deactivation, modification of MCM-68 with lanthanum oxide simply by impregnation was performed. The La-modification mainly deactivated the active site on the external surface and was found to be an effective way for avoiding heavy coke formation to maintain catalytic activity and selectivity to propylene. (C) 2013 Elsevier B.V. All rights reserved.