New polymer-immobilized peroxotungsten compound as an efficient catalyst for selective and mild oxidation of sulfides by hydrogen peroxide

Abstract A new polymer-bound peroxotungstate(VI) catalyst of the type [W(O) 2 (O 2 )(CN) 2 ]–PAN [PAN = poly(acrylonitrile)] ( PANW ) has been prepared by reacting H 2 WO 4 with 30% H 2 O 2 and the macromolecular ligand, PAN at pH 5.0. The compound was characterized by elemental analysis, SEM, EDX, TGA and spectral studies (FTIR and 13 C NMR). Clean conversion of a variety of sulfides and dibenzothiophene (DBT) to the corresponding sulfoxide or sulfone, using H 2 O 2 as oxidant, could be achieved in the presence of the heterogeneous catalyst PANW , by a versatile variation of reaction conditions. The reactions proceed under mild conditions to afford the resulting products with impressive turn over frequency (TOF). The catalyst exhibit complete chemoselectivity toward sulfur group of substituted sulfides with other oxidation prone functional groups. Easy regeneration and reusability of the catalyst for at least up to seven catalytic cycles with consistent activity and selectivity is an important attribute of the catalyst.