Synthesis of amphiphilic peroxophosphomolybdates for oxidative desulfurization of fuels in ionic liquids

Three amphiphilic peroxophosphomolybdates [C 4 mim] 3 PMo 4 O 24 , [C 8 mim] 3 PMo 4 O 24 and [C 16 mim] 3 PMo 4 O 24 were synthesized and characterized. These catalysts were used for extraction and catalytic oxidative desulfurization of fuel with H 2 O 2 as an oxidant and ionic liquid [C 4 mim]BF 4 as an extractant. It was found that [C 16 mim] 3 PMo 4 O 24 showed the highest catalytic activity and the sulfur content could decrease to 7.5 ppm. In contrast, the desulfurization system shows very low performance without H 2 O 2 or ionic liquid. The detailed reaction conditions were optimized including reaction time, temperature, the dosage of H 2 O 2 and catalyst, and different sulfur compounds. After the reaction, the catalysts and the ionic liquid can be cycled 8 times with a little decrease in desulfurization efficiency.