Removal of Thiophenic Sulfur Compounds from Oil Using Chlorinated Polymers and Lewis Acid Mixture via Adsorption and Friedel-Crafts Alkylation Reaction

For efficient removal of thiophenic sulfur (S-) compounds from oils, a novel method is proposed here, i.e. one-pot alkylation desulfurization (OADS), in which oil insoluble chlorinated polymer such as polyvinyl chloride (PVC) is used as the alkylating regent with Lewis acid as catalyst. The aromatic S-compounds are grafted to the polymer through Friedel-Crafts reaction and removed facilely along with the polymer. The OADS mechanism is identified by scanning electron microscope and analyzer with surface area and pore size of the polymer. The influence of some factors on the OADS is studied, e.g. the type and amount of chlorinated polymers and Lewis acids. It is proved that thiophene and benzothiophene can be removed efficiently from oil by PVC+AlCl3 mixture even in the presence of 25% (by mass) of benzene due to the synergetic effects of the adsorptive desulfurization of AlCl3 and the alkylation desulfurization of PVC.