Selective production of propylene from methanol: Mesoporosity development in high silica HZSM-5
Selective production of propylene from methanol: Mesoporosity development in high silica HZSM-5
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DOI：
10.1016/j.jcat.2008.06.019
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发表时间：
2008-08-15
影响因子：
7.3
通讯作者：
Gao, Zi
中科院分区：
文献类型：
--
作者：
Mei, Changsong;Wen, Pengyu;Gao, Zi
采用碱脱硅和软模板法对高硅HZSM-5进行了中孔化处理，并研究了中孔化与改性催化剂甲醇制丙烯反应性能的关系。在碱脱硅改性的高硅HZSM-5催化剂上，丙烯选择性和丙烯/乙烯比分别为42.2%和10.1。催化性能的增强可归因于沸石晶体表面新产生的开放介孔以及低布朗斯台德酸性。通过软模板法可以在HZSM-5晶体中容易地形成大量的介孔。然而，在该方法中形成的介孔随机分布在沸石晶体中，并且在反应的分子传输中起次要作用，因此催化剂的丙烯选择性和丙烯/乙烯比的改善不太明显。改性HZSM-5催化剂上丙烯选择性和丙烯/乙烯比的提高（特别是碱处理）可能与MTP反应中甲基芳烃和烯烃甲基化/裂解途径的不同贡献有关。(c)2008年爱思唯尔公司All rights reserved.
The mesoporosity development in high silica HZSM-5 was carried out by alkaline desilication treatment and soft template method, and its relationship with the catalytic performance of the modified catalysts in methanol-to-propylene reaction was studied. High propylene selectivity (42.2%) and propylene/ethylene ratio (10.1) were observed on the high silica HZSM-5 catalyst modified by alkaline desilication. The enhanced catalytic performance can be attributed to the newly created open mesopores on the surface of the zeolite crystals together with the low Bronsted acidity. A greater amount of mesoporosity could be readily formed in HZSM-5 crystals via the soft template route. However, the mesopores formed in this method are randomly distributed in the zeolite crystals and play a minor role in the molecular transport of the reaction, so the improvement in propylene selectivity and propylene/ethylene ratio of the catalyst is less evident. The higher propylene selectivity and propylene/ethylene ratio on modified HZSM-5 (especially by alkaline treatment) than unmodified HZSM-5 could be also related to different contributions of the methylaromatics route and olefins methylation/cracking route in MTP reaction. (c) 2008 Elsevier Inc. All rights reserved.