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Synthesis of Sn‐Beta with Exclusive and High Framework Sn Content
Author(s) -
van der Graaff William N. P.,
Li Guanna,
Mezari Brahim,
Pidko Evgeny A.,
Hensen Emiel J. M.
Publication year - 2015
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201403050
Subject(s) - zeolite , catalysis , chemistry , anhydrous , physisorption , calcination , lewis acids and bases , molecular sieve , methanol , dihydroxyacetone , hydrothermal synthesis , inorganic chemistry , selectivity , nuclear magnetic resonance spectroscopy , hydrolysis , nuclear chemistry , medicinal chemistry , hydrothermal circulation , organic chemistry , chemical engineering , glycerol , engineering
Sn‐Beta zeolite was prepared by acid dealumination of Beta zeolite, followed by dehydration and impregnation with anhydrous SnCl 4 . The formation of extraframework Sn (EFSn) species was prevented by the removal of unreacted SnCl 4 in a methanol washing step prior to calcination. The resulting Sn‐Beta zeolites were characterized by X‐ray diffraction, Ar physisorption, NMR, UV/Vis, and FTIR spectroscopy. These well‐defined Lewis acid zeolites exhibit good catalytic activity and selectivity in the conversion of 1,3‐dihydroxyacetone to methyl lactate. Their performance is similar to a reference Sn‐Beta zeolite prepared by hydrothermal synthesis. Sn‐BEA zeolites that contain EFSn species exhibit lower catalytic activity; the EFSn species also catalyze formation of byproducts. DFT calculations show that partially hydrolyzed framework Sn‐OH species (open sites), rather than the tetrahedral framework Sn sites (closed sites), are the most likely candidate active sites for methyl lactate formation.