SO2 oxidation by heteropolyacids (HPA) and dioxygen in HPA presence in aqueous solutions

Jumakaeva, B.S.; Golodov, V.A.

doi:10.1016/0304-5102(86)87077-8

Cited by 14 publications

(3 citation statements)

References 5 publications

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“…The authors suggested that the reaction proceeds through electron transfer from SO 2 to the polyoxometalate followed by nucleophilic attack of water onto the activated SO 2 , followed by reoxidation of the catalyst by O 2 . 398 Although the oxidation of sulfides with hydrogen peroxide and organic peroxides often does not require a catalyst, the oxidation of sulfides with molecular oxygen does require a catalyst. Early research showed that dialkylsulfides, R 2 S where R = Me, Et, and Bu could be oxidized in quantitative yields to a mixture of the corresponding sulfoxides and sulfones in a reaction preferably catalyzed by H 3+x PV x Mo 12-x O 40 (x = 2 or 3) under high O 2 pressures and elevated temperatures.…”

Section: Oxidation Of Sulfidesmentioning

confidence: 99%

Dioxygen in Polyoxometalate Mediated Reactions

2017

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In this review article, we consider the use of molecular oxygen in reactions mediated by polyoxometalates. Polyoxometalates are anionic metal oxide clusters of a variety of structures that are soluble in liquid phases and therefore amenable to homogeneous catalytic transformations. Often, they are active for electron transfer oxidations of a myriad of substrates and upon reduction can be reoxidized by molecular oxygen. For example, the phosphovanadomolybdate, HPVMoO, can oxidize Pd(0) thereby enabling aerobic reactions catalyzed by Pd and HPVMoO. In a similar vein, polyoxometalates can stabilize metal nanoparticles, leading to additional transformations. Furthermore, electron transfer oxidation of other substrates such as halides and sulfur-containing compounds is possible. More uniquely, HPVMoO and its analogues can mediate electron transfer-oxygen transfer reactions where oxygen atoms are transferred from the polyoxometalate to the substrate. This unique property has enabled correspondingly unique transformations involving carbon-carbon, carbon-hydrogen, and carbon-metal bond activation. The pathway for the reoxidation of vanadomolybdates with O appears to be an inner-sphere reaction, but the oxidation of one-electron reduced polyoxotungstates has been shown through intensive research to be an outer-sphere reaction. Beyond electron transfer and electron transfer-oxygen transfer aerobic transformations, there a few examples of apparent dioxygenase activity where both oxygen atoms are donated to a substrate.

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Section: Oxidation Of Sulfidesmentioning

confidence: 99%

Dioxygen in Polyoxometalate Mediated Reactions

2017

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“…Indeed, Keggin based catalysts can be used in numerous catalytic processes such as oxidation catalysts for alkanes, alkenes, alcohols, aldehydes and sulphides to alcohols, ketones, epoxides, allylic alcohols, allylic ketones and sulphoxides. [90][91][92][93][94][95][96] Even though the molybdenum and tungsten based POMs are good acid and redox catalysts on their own, it was soon realized the potential use of transition metals as co-catalysts in order to improve their selectivity and finely tune their efficiency. For example, Mizuno et al demonstrated that the cooperative effect of the mixed addenda Cs 2.5 H 1.5 PVMo 11 O 40 Keggin compound in the presence of different transition metals.…”

Section: Homo-and Heterogeneous Pom -Based Catalystsmentioning

confidence: 99%

Engineering polyoxometalates with emergent properties

et al. 2012

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Polyoxometalates are clusters of metal-oxide units, comprising a large diversity of nanoscale structures, and have many common building blocks; in fact polyoxometalate clusters are perhaps the largest non-biologically derived molecules structurally characterised. Not only can polyoxometalates have gigantic nanoscale molecular structures, but they also a have a vast array of physical properties, many of which can be specifically 'engineered-in'. Here we describe how building block libraries of polyoxometalates can be used to construct systems with important catalytic, electronic, and structural properties. We also show that it is possible to construct complex chemical systems based upon polyoxometalates, manipulating the templating/self templating rules to exhibit emergent processes from the molecular to the macroscopic scale.

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“…Specifically, the PEG is used as solvent for known polyoxometalate catalyzed aerobic oxidations. 5 With H 5 PV 2 Mo 10 O 40 , it is possible to directly oxidize benzylic alcohols to aldehydes, 6 to dehydrogenate cyclic dienes to the corresponding aromatic derivatives, 7 to oxidize sulfides to sulfoxides and sulfones, 8 and to use the polyoxometalate as co-catalyst in palladium catalyzed Wacker oxidations. 9 Initially the concept of using polyethylene glycol as solvent was tested using the oxidation of benzylic alcohols to benzaldehydes, eqn.…”

mentioning

confidence: 99%