Temperature-Responsive Polyoxometalate Catalysts for DBT Desulfurization in One-Pot Oxidation Combined with Extraction

Abstract

Intelligent thermo-responsive catalysts [C16H33N(CH3)3]3[PO4{MO(O2)2}4]/poly(N-isopropylacrylamide) (M = Mo and W, abbreviated as C16PM(O2)2/PNIPAM) have been prepared using thermo-responsive polymer PNIPAM as a support. The thermo-responsive hybrids exhibit novel switchable property based on the change of temperature, while its solubility in organic solvent is reversibly controllable through an external temperature stimulus linking the gap between heterogeneous catalysis and homogeneous one. Moreover, non-polar organic substrates are accumulated around the catalytic sites by two synergistic effects of amphiphilic POM molecules and the existence of PNIPAM. Therefore, this solid hybrid has been successfully used in catalyzing the oxidation of refractory sulfur-containing compound dibenzothiophene into its corresponding sulfone with high selectivity in the presence of H2O2. Application of this catalyst brings about an efficient, useful and green process in desulfurization through extraction and oxidation simultaneously.