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Synthesis, Characterization, and Catalytic Properties of SiPW‐X Mesoporous Silica with Heteropolyacid Encapsulated into Their Framework
Author(s) -
Shi Chunfeng,
Wang Runwei,
Zhu Guangshan,
Qiu Shilun,
Long Jun
Publication year - 2005
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200500488
Subject(s) - tetraethyl orthosilicate , chemistry , catalysis , mesoporous material , hydrolysis , benzoic acid , acetic acid , magic angle spinning , mesoporous silica , heterogeneous catalysis , nuclear chemistry , inorganic chemistry , chemical engineering , organic chemistry , nuclear magnetic resonance spectroscopy , engineering
A series of SiPW‐X mesoporous silica with Keggin‐type heteropolyacids (HPAs) encapsulated into their framework have been synthesized under strong acidic conditions. During hydrolysis of tetraethyl orthosilicate (TEOS), Na 2 HPO 4 (P source) and Na 2 WO 4 (W Source) are added into the initial sol‐gel system to form Keggin type HPAs. The final products have been intensively characterized by various techniques, such as XRD, TEM, N 2 adsorption isotherm analysis, and by IR, UV/Visible, and 31 P Magic Angle Spinning (MAS) NMR spectroscopy. Characterization results suggest that samples with an HPA weight percent of 13.3–20.7 % show very ordered hexagonal mesostructures. In addition, HPAs incorporated in the mesosilica are insoluble during catalysis. Results of catalytic tests show that SiPW‐X materials have catalytic activities that are comparable to bulk HPA in catalytic tests implementing chemical reactions of both small (cumene cracking and esterification of ethanol with acetic acid) and bulky (1,3,5‐triisopropylbenzene cracking and esterification of benzoic acid with tert ‐butyl alcohol) molecules. It can be readily separated from the reaction system for reuse, which suggests the potential industrial application. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)