Back to Search
Start Over
Peroxometalates Immobilized on Magnetically Recoverable Catalysts for Epoxidation.
- Source :
- ChemPlusChem; Dec2012, Vol. 77 Issue 12, p1128-1138, 11p
- Publication Year :
- 2012
-
Abstract
- Magnetically separable catalysts were prepared and employed for the epoxidation of olefins with hydrogen peroxide. In all cases the magnetic core was firstly covered with a silica layer to prevent iron ion-initiated decomposition of hydrogen peroxide. The catalytic active species, an ionic liquid-type peroxotungstate, was then immobilized either by hydrogen bonding (catalyst 1) or by covalent SiO linkage (catalyst 2). In addition to a thorough characterization by FT-IR, XRD, NMR, DRIFT, XPS, and TEM, the catalytic potential was evaluated in the epoxidation of a variety of olefins as well as allylic alcohols. Both catalysts showed essentially a constant activity after at least ten consecutive cycles. On the basis of the research above, a new type of magnetically separable catalyst was constructed by immobilization of lacunary-type phosphotungstate by hydrogen bonding between the sulfonate anion and silanol group on the surface of the core-shell magnetic nanoparticles. After the detailed characterization, the catalyst was used in the epoxidation of a variety of olefins and allylic alcohols and was found to possess high activity, selectivity towards epoxides, and a constant activity after at least ten catalytic recycles without solvent. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 21926506
- Volume :
- 77
- Issue :
- 12
- Database :
- Complementary Index
- Journal :
- ChemPlusChem
- Publication Type :
- Academic Journal
- Accession number :
- 84307044
- Full Text :
- https://doi.org/10.1002/cplu.201200246