The ionic liquid coupling "oxidation-extraction" method has been used to remove dibenzothiophen（DBT） in model oil

using silica gel-supported dendrimer-like vanadium complex as catalyst and tert-butyl hydroperoxide（TBHP） as oxidant.Studies showed that the conversion rate of DBT was improved apparently and the oxidation products（DBTO and DBTO2） in model oil were also decreased quickly when the desulfurization system contained oxidant and ionic liquid synchronously.Moreover

the DBT removal rate can reach 95.0% when the oxidation temperature is 90 ℃

time is 60 min

O/S is 3∶1

and the volume ratio of PF6 to model oil is 1∶3.The oxidation activity did not have apparent decrease even after the coupling system had been recycled for six times.