Polyoxometalate catalysis for oxidative desulfurization



Yahya, Rana
(2015) Polyoxometalate catalysis for oxidative desulfurization. Doctor of Philosophy thesis, University of Liverpool.

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Abstract

Oxidative desulfurization removes sulfur-containing molecules from petroleum feedstocks to upgrade the quality of fuels. It is driven by environmental legislation demanding very low sulfur levels in fuels. The oxidative desulfurization technology usually involves oxidation of sulfur-containing molecules with an appropriate oxidant, e.g. hydrogen peroxide, organic peroxide, etc., followed by extraction of oxidation products from the petroleum feedstock. In this study, new efficient catalysts have been developed for the oxidation of benzothiophenes commonly found in diesel fuel, such as benzothiophene, dibenzothiophene and 4,6-dimethyldibenzothiophene, to the corresponding sulfones with hydrogen peroxide in two-phase system including immiscible aqueous and organic phases. These catalysts are based on polyoxometalates comprising Keggin type heteropolyanions [XM12O40]m- {X= Pv (m = 3) and Siv (m = 4) and phase transfer agents such as aminocyclotriphosphozenes or terminally functionalized polyisobutylene (PIB) oligomers. In this system, Keggin polyanions are transformed by excess H2O2 in aqueous phase to active peroxo polyoxometalate species which are transferred to the organic phase by the phase transfer agent where the oxidation of sulfur-containing molecules takes place.

Item Type: Thesis (Doctor of Philosophy)
Subjects: Q Science > QD Chemistry
Divisions: Fac of Science & Engineering > School of Chemistry
Depositing User: Symplectic Admin
Date Deposited: 31 Aug 2016 07:25
Last Modified: 31 Aug 2016 07:25
URI: http://livrepository.liverpool.ac.uk/id/eprint/2052079
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