Oxidation of Sulfides and Olefins in the Presence of Nanocluster Polyoxotungstate–intercalated Layered Double Hydroxide Nanoparticles as a Catalyst

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Qoreishi Kavardi, Atefeh Sadat | 2016

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 48757 (03)
University: Sharif University of Technology
Department: Chemistry
Advisor(s): Bagherzadeh, Mojtaba
Abstract:
In this study, polyoxometalate (POM) intercalated in the layered double hydroxide (LDH) was synthesized by a selective ion-exchange method. For this purpose, the nanocluster [VW12O40]3- was immobilized on the Mg2+/A13+/Cl–LDH support. The heterogeneous catalyst was characterized by FT-IR, XRD, SEM and analysis of ICP. The LDH-POM was applied as a catalyst in efficient oxidation of sulfides to sulfoxides using UHP as oxidant and CH3OH/ CH¬2¬Cl¬2 ¬as a solvent at room temperature, as well as epoxidation of olefins using TBHP as an oxidants and C¬2H4Cl2 as a solvent in 84°C. This catalyst showed excellent catalytic activities for a substrate/catalyst ratio (200:1). For example, this catalytic system, completely convert methyl phenyl sulfide to methyl phenyl sulfoxide (100%) and cyclooctene changing to corresponding epoxide with 82% conversion. The heterogeneous LDH-POM catalyst shows much higher epoxide selectivity than the corresponding homogeneous polyoxotungstate (POM) catalyst, which can be attributed to the beneficial effect of basic LDH host. The LDH-POM showed acceptable reactivity in oxidation, without significant loss of activity within three successive runs
Keywords:
Heterogeneous Catalysis ; Ion Exchange ; Nano-Cluster ; Nano Catalyst ; Layered Double Hydroxide (LDH) ; Polyoxtungstate

Oxidation of sulfides and olefins in the presence of nanocluster polyoxotungstate –intercalated layered double hydroxide nanoparticles as a catalyst