OXIDATIVE DESULFURIZATION OF OILS VIA HYDROGEN-PEROXIDE AND HETEROPOLYANION CATALYSIS

Oxidation of dibenzothiophene with hydrogen peroxide using phosphotung stic acid as catalyst and tetraoctylammonium bromide as phase transfer agent in a mixture of water and toluene has been studied. Catalysed d ecomposition of hydrogen peroxide competes with dibenzothiophene oxida tion but by choice of suitable conditions yields of dibenzothiophene s ulphone approaching 100% may be obtained. Treatment of gas oils with t his technology shows that all the sulphur compounds present are oxidis ed by this catalyst system and highly substituted dibenzothiophenes ar e the most readily oxidised of species containing a thiophene nucleus. Oxidised sulphur compounds can be separated from the oil by adsorptio n on silica gel. The use of oxidation and adsorption in a process for desulphurisation of gas oils is discussed.