A water soluble heteropolyoxotungstate as a selective, efficient and environment friendly oxidation catalyst

Abstract

A series of water soluble Keggin type heteropolyoxotungstates have been tested as oxidation catalysts in aqueous-biphasic media with dilute H 2 O 2 (30%) as the oxygen atom donor, without using any phase transfer agent. The Zn substituted polyoxoanion {(NH 4 ) 7 Zn 0⋅5 [α-ZnO 4 W 11 O 30 ZnO 5 (OH 2 )]⋅nH 2 O} has been found to be the most efficient catalyst, which oxidizes a wide range of organic functionalities with good turnovers and high selectivities. The functionalities that undergo oxidations are: organic sulfides, pyridines, anilines, benzyl alcohols and benzyl halides. The oxidations of sulfides to sulfoxides and/or sulfones have been studied in detail, and a simple kinetic model consisting of two consecutive reactions, is shown to give good fit with the experimental data. In the catalytic system described here product isolation is easy, and the aqueous catalyst solution can be re-used several times with little loss in its efficiency.

Nonanebis (peroxoic acid)‐Mediated Transition‐Metal‐Free Approach for N‐Oxide Synthesis

“…They also serve as an oxidant for various reactions,, ligand in metal complexes, auxiliary agent and as a protecting group . Efforts were made by several research groups using heteropolyacids, meta‐chloroperbenzoic acid, peraceticacid, oxiranes and dioxiranes, Caro's acid (H 2 SO 5 ), magnesium monophthalate . Catalytic processes includes peroxides such as tert.…”

Extractive oxidative desulfurization of model oil/crude oil using KSF montmorillonite-supported 12-tungstophosphoric acid

“…Previous reports have demonstrated the effective catalytic performances of supported HPAs for the oxidation of thiophene (T) and its derivatives with different oxidants (Hui-Peng et al 2007;Kukovecz et al 2002;Yan et al 2009b). However, most of the research up to now has investigated homogenous or amphiphilic catalysts and oxidants (Gao et al 2006;Zhang et al 2012a, b;Maity et al 2009;Qiu et al 2009;Xue et al 2012;Bhutto et al 2016). In these systems, the catalysts are usually dissolved in the continuous phase or inside the emulsion droplets; thus, it is difficult to separate the catalysts and recycle them from the emulsion systems.…”

Barium, calcium and magnesium doped mesoporous ceria supported gold nanoparticle for benzyl alcoholoxidation using molecular O2

“…[7][8][9][10] In particular, selective liquid phase aerobic oxidation of alcohols to corresponding carbonyl compounds using solid catalysts under mild conditions is a shared desire from an economic and environmental perspectives. 11,12 Synthesis and development of CeO 2 nanomaterials 13,14 with enhanced thermal, redox and acid-base properties is of paramount interest in designing catalysts for specific catalytic reactions. For example, in three-way catalysis (TWC) for the treatment of automotive internal combustion of engine exhaust gases, one of the most important properties of ceria is oxygen storage capacity, due to the Ce 4+ /Ce 3+ redox cycles between its lattice ions.…”