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Indexed by:期刊论文

Date of Publication:2017-07-15

Journal:MICROPOROUS AND MESOPOROUS MATERIALS

Included Journals:SCIE、EI

Volume:247

Page Number:158-165

ISSN No.:1387-1811

Key Words:Sn-zeolite; Germanosilicate; F-19 MAS NMR; Homogenous distribution; Glucose isomerization

Abstract:Sn-zeolites are important solid Lewis acid catalysts with wide applications to the conversions of various biomass-derived carbohydrates. As the catalytic center, framework Sn of Sn-zeolites can catalyze glucose isomerization to fructose and epimerization to mannose. In practical use, the main obstacle to the application of Sn-zeolites is the lengthy crystallization. In present work, we developed a rapid synthesis route to Sn-zeolites by incorporating Sn into the germanosilicate framework of BEC zeolite via direct hydrothermal procedure. The synthesis time required by Sn-BEC is tenfold shortened than that by the traditional Sn-zeolites like Sn-Beta. The locations of framework Sn atoms of Sn-BEC were investigated by F-19 MAS NMR and computational modeling, which indicates that the framework Sn sites of Sn-BEC adopt a uniquely homogenous distribution at the T-1 sites. Sn-BEC exhibits high reaction activity and single isomerization selectivity in the glucose conversion in methanol, while Sn-Beta shows both isomerization and epimerization selectivity. The single isomerization selectivity of Sn-BEC suggests the presence of single catalytic center, which is probably caused by the homogenous distribution of framework Sn sites. (C) 2017 Elsevier Inc. All rights reserved.