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Mesostructured Dihydroxy‐Functionalized Guanidinium‐Based Polyoxometalate with Enhanced Heterogeneous Catalytic Activity in Epoxidation
Author(s) -
Chen Guojian,
Zhou Yu,
Zhao Pingping,
Long Zhouyang,
Wang Jun
Publication year - 2013
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201300105
Subject(s) - polyoxometalate , phosphotungstic acid , catalysis , ionic liquid , sorption , chemistry , heterogeneous catalysis , transmission electron microscopy , chemical engineering , inorganic chemistry , materials science , nanotechnology , organic chemistry , adsorption , engineering
A mesostructured ionic liquid–polyoxometalate (IL‐POM) hybrid has been prepared through designing a new dihydroxy‐tethered guanidinium‐based IL, N ′′‐(2,3‐dihydroxypropyl)‐ N , N , N ′, N ′‐tetramethylguanidinium chloride, to interact with Keggin‐type POM phosphotungstic acid (H 3 PW) in a self‐assembly process. Scanning electron microscopy and transmission electron microscopy showed its special coral‐shaped micromorphology. Nitrogen sorption analysis indicated the formation of a porous structure with a moderate surface area of about 30 m 2 g −1 and narrowly distributed pore size located in the mesoscale. Assessed in the cis ‐cyclooctene epoxidation with H 2 O 2 , the mesostructured hybrid exhibited superior heterogeneous catalytic activity and steady reusability, and the conversion was more than four times that of homogeneous H 3 PW itself, and more than 14 times that of the nonporous analogues. On the basis of the experimental results, a unique “substrate–solvent–catalyst” synergistic mechanism is proposed and discussed for understanding the dramatically enhanced catalytic performance.