Homogeneous catalytic oxidation of styrene and styrene derivatives with hydrogen peroxide in the presence of transition metal-substituted polyoxotungstates
authors Duarte, TAG; Estrada, AC; Simoes, MMQ; Santos, ICMS; Cavaleiro, AMV; Neves, MGPMS; Cavaleiro, JAS
nationality International
journal CATALYSIS SCIENCE & TECHNOLOGY
keywords BAEYER-VILLIGER OXIDATION; KEGGIN-TYPE POLYOXOTUNGSTATES; ONE-POT SYNTHESIS; SELECTIVE OXIDATION; SUPPORTED UNDECATUNGSTOPHOSPHATE; AROMATIC-ALDEHYDES; ACTIVE CATALYSTS; ALKENE OXIDATION; EPOXIDATION; BENZALDEHYDE
abstract The tetrabutylammonium (TBA) salts of the Keggin-type polyoxotungstates with general formula [XW11M(H2O)O-39]((n-m)-), where X = P, B or Si and M = Mn, Fe or Co, were evaluated as catalysts in the oxidation of styrene, alpha-methylstyrene, p-methylstyrene, alpha,p-dimethylstyrene, p-chlorostyrene, p-nitrostyrene, and p-methoxystyrene under mild conditions, using aqueous H2O2 as an eco-sustainable oxidant. In this study, the influence of the catalysts and of the different styrene substituents on the oxidation reaction profile was evaluated in terms of conversion and selectivity. For all the performed catalytic studies, the main product results from the oxidative cleavage of the vinyl double bond, except in the case of the oxidation of p-methoxystyrene catalysed by BW11Mn, for which p-methoxyphenol is the main product. The catalysts BW11Mn and SiW11Co give rise to 100% conversion for almost all of the substrates, excluding p-methoxystyrene and p-nitrostyrene for both catalysts and alpha,p-dimethylstyrene only in the case of BW11Mn. The selectivity for C=C cleavage products resulting from the oxidative cleavage of the vinyl double bond can be as high as 98%, reaching 98% conversion for p-nitrostyrene when SiW11Co was used as a catalyst. Possible pathways are discussed and the oxidation of a few presumed intermediates was carried out. The systematic study of several substituted styrene derivatives suggests a possible reactivity order for these compounds in the catalytic system considered.
publisher ROYAL SOC CHEMISTRY
issn 2044-4753
year published 2015
volume 5
issue 1
beginning page 351
ending page 363
digital object identifier (doi) 10.1039/c4cy00702f
web of science category Chemistry, Physical
subject category Chemistry
unique article identifier WOS:000348358200038
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journal impact factor (jcr 2016): 5.773
5 year journal impact factor (jcr 2016): 5.809
category normalized journal impact factor percentile (jcr 2016): 81.724
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