Abstract: Benzothiophenes were the main residual sulfides in hydrofining diesels. Based on the complexation mechanism between thiophenes and metal ions, four kinds of metal chlorides such as CuCl2, AlCl3, FeCl3 and MnCl2 were selected as complexation desulfurizers for desulfurization research on shallow hydrogenated diesel with sulfur mass fraction of 592 μg/g. The results indicated that at the same conditions, the desulfurization effect of AlCl3 was the best in one-component metal chloride, and that of CuCl2 /AlCl3 in two-component metal chloride was the best when the mass ratio of CuCl2 /AlCl3 was 1:1. Considering the process cost and operation cycle, the optimum process conditions were as follows: 50 ℃, reaction 30 min with the mass fraction of complex desulfurizer of 10%. Under optimal process conditions, the desulfurization rate of AlCl3 can reach 86%, and that of CuCl2/AlCl3 can reach 95% when the mass ratio of CuCl2/AlCl3 was 1∶1.

Key words: metal chlorides, benzothiophene, complexation desulfurization, hydrofining diesel