Graphene modified porous organic polymer supported phosphotungstic acid catalyst for alkylation desulfurization

A new strategy of using graphene to modify porous organic solid acid catalyst for alkylation desulfurization is proposed by taking advantage of the π-π interaction between graphene and thiophenic sulfur. A graphene-modified sulfonated porous organic polymer (POP) supported phosphotungstic acid (HPW) catalyst (HPW/POP-G-SO₃H) is successfully prepared by the solution polymerization-sulfonation-impregnation method. Steam adsorption experiment results show that graphene modification could increase the adsorption capacity of 3- methylthiophene (3-MT), but has little effect on the adsorption of isopentane; therefore, the selective adsorption of 3-MT could be enhanced. DFT calculations plus dispersion corrections also show that the adsorption energy of 3-MT on graphene is higher than that of isopentene on graphene and higher than those of 3-MT and isopentene on sulfonated POP. Subsequently, the catalytic activity test of alkylation desulfurization confirms that graphene-modified supported HPW catalyst shows higher alkylation desulfurization activity. This could support our assumptions. After recycles of 6 times, the 3-MT conversion on HPW/POP-G-SO₃H catalyst decreases slightly, which possesses good recycling performance. Therefore, HPW/POP-G-SO₃H catalyst will have broad application prospects in the field of alkylation desulfurization.