Kamimura Yoshihiro, Itabashi Keiji, Kon Yoshihiro, Endo Akira, Okubo Tatsuya
Department of Chemical Process, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan.
Department of Chemical System Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
Chem Asian J. 2017 Mar 2;12(5):530-542. doi: 10.1002/asia.201601569. Epub 2017 Feb 1.
The seed-assisted synthesis of zeolites without using organic structure-directing agents (OSDAs) has enabled alternative routes to the simple, environmentally friendly and low-cost production of industrially important zeolites. In this study, the successful seed-assisted synthesis of MCM-22 (MWW-type) zeolite with an OSDA-free gel is reported for the first time. MWW-type zeolites are obtained by the addition of as-synthesized MCM-22 seeds prepared with hexamethyleneimine (HMI) into OSDA-free Na-aluminosilicate gels. Based on the results of XRD, ICP-AES, NMR, N physisorption and NH -TPD, the product exhibited different features compared to those of the seeds. The H-form product can serve as a catalyst in Friedel-Crafts alkylation reaction of anisole with 1-phenylethanol, and its catalytic activity is comparable to the seeds. Furthermore, XRD, FE-SEM, TG-DTA, CHN, FT-IR and NMR analyses of products and intermediates provide insights into the role of seeds and occluded HMI, the crystallization process, and key factors for achieving seed-assisted synthesis of MWW-type zeolites with an OSDA-free gel system. The present results provide a new perspective for the economical and environmentally friendly production of MWW-type zeolites.
在不使用有机结构导向剂（OSDA）的情况下，通过晶种辅助合成沸石为工业上重要的沸石的简单、环保和低成本生产开辟了替代途径。在本研究中，首次报道了使用无OSDA的凝胶成功通过晶种辅助合成MCM-22（MWW型）沸石。MWW型沸石是通过将用六亚甲基亚胺（HMI）制备的合成态MCM-22晶种添加到无OSDA的钠铝硅酸盐凝胶中获得的。基于XRD、ICP-AES、NMR、N物理吸附和NH -TPD的结果，产物与晶种相比表现出不同的特征。H型产物可作为苯甲醚与1-苯乙醇的傅克烷基化反应的催化剂，其催化活性与晶种相当。此外，对产物和中间体的XRD、FE-SEM、TG-DTA、CHN、FT-IR和NMR分析为晶种和包埋的HMI的作用、结晶过程以及在无OSDA凝胶体系中实现MWW型沸石晶种辅助合成的关键因素提供了深入了解。目前的结果为MWW型沸石的经济和环境友好生产提供了新的视角。
