Extractive desulfurization of fuel oil with metal-based ionic liquids

Several metal-based ionic liquids (ILs) were synthesized and used as extractants for the desulfurization of dibenzothiophene (DBT) in simulated fuel oil. The effects of several anion and metal ions, n(ILs)/n(metal) as mole ratio, VIL/Voil and extractive times on the removal ratio of DBT were investigated in detail. The results showed that [BMIM]HSO4/FeCl3 (BMIM was short for 1-butyl-3-methyl imidazole) was superior to the other ILs for the extractive desulfurization. A total of 100% of DBT was removed at room temperature in 5 min with V[BMIM]HSO4/FeCl3/Voil=1:1V[BMIM]HSO4/FeCl3/Voil=1:1. The extractive activity of [BMIM]HSO4/FeCl3 IL did not change almost after five runs. Extractive desulfurization of different sulfur compounds and commercial diesel fuel oil were also examined. The removal ratios of the sulfur compounds as the reaction substrates were all over 90% and the sulfur content of commercial diesel oil decreased to 120 ppm from 12,400 ppm.

It is commonly acknowledged that the characteristic absorption peak of [BMIM]HSO4 are at 3148 cm−1, 2961 cm−1, 1573 cm−1, 1170 cm−1, 847 cm−1, which are all shown in the graph above. In addition, as demonstrated in the graph above, with an increase in the amount of FeCl3, the strength of the hydrogen bond increased because of the existence of the larger FeCl4− anion.Figure optionsDownload as PowerPoint slide