Hybrid polyoxotungstates as functional comonomers in new cross-linked catalytic polymers for sustainable oxidation with hydrogen peroxide

Abstract

Anchoring terminal octenyl tails on molecular polyoxotungstates yield polymerizable organic-inorganic monomers with formula [{CH(2)=CH(CH(2))(6)Si}(x)O(y)SiW(w)O(z)](4-) [x = 2, w = 11, y = 1, z = 39 (1); x = 2, w = 10, y = 1, z = 36 (2); and x = 4, w = 9, y = 3, z = 34 (3)]. These molecular hybrids can use aqueous hydrogen peroxide to catalyze the selective oxidation of organic sulfides in CH(3)CN. Copolymerization of 1-3 with methyl methacrylate and ethylene glycol dimethacrylate leads to porous materials with a homogeneous distribution of the functional monomers, as indicated by converging evidence from FTIR spectroscopy and electronic microscopy. The catalytic polymers activate hydrogen peroxide for oxygen transfer, as demonstrated by the quantitative and selective oxidation of methyl p-tolyl sulfide, which was screened as model substrate. The hybrid material containing monomer 2 was also tested in n-octane to evaluate its potential for the oxidation and removal of dibenzothiophene, a well-known gasoline contaminant.