Mesostructured Dihydroxy‐Functionalized Guanidinium‐Based Polyoxometalate with Enhanced Heterogeneous Catalytic Activity in Epoxidation. Issue 6 (26th April 2013)

• Record Type: Journal Article
• Authors: Chen, Guojian; Zhou, Yu; Zhao, Pingping; Long, Zhouyang; Wang, Jun
• Is Part Of: ChemPlusChem. Volume 78:Issue 6(2013:Jun.)
• Page Start: 561
• Page End: 569
• Publication Date: 2013-04-26
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1002/cplu.201300105
• Languages: English
• ISSNs: 2192-6506

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A mesostructured ionic liquid–polyoxometalate (IL‐POM) hybrid has been prepared through designing a new dihydroxy‐tethered guanidinium‐based IL, <italic>N</italic>′′‐(2, 3‐dihydroxypropyl)‐<italic>N</italic>, <italic>N</italic>, <italic>N</italic>′, <italic>N</italic>′‐tetramethylguanidinium chloride, to interact with Keggin‐type POM phosphotungstic acid (H₃PW) 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 m² g⁻¹ and narrowly distributed pore size located in the mesoscale. Assessed in the <italic>cis</italic>‐cyclooctene epoxidation with H₂O₂, the mesostructured hybrid exhibited superior heterogeneous catalytic activity and steady reusability, and the conversion was more than four times that of homogeneous H₃PW 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.</p> </abstract>