用BMIMCu2Cl3离子液体萃取脱除汽油中的硫化物

A moisture stable ionic liquid that contains Cu(Ⅰ) was used as solvent for desulfurization from gasoline in this paper. CuC1 was mixed with 1-butyl-3-methylimidazolium (BMIM) chloride according to the molar ratio of 2∶1 to synthesize BMIMCu2Cl3 ionic liquid. BMIMZn2Cl5 and Et3NHCu2Cl3(Et=ethyl) were prepared in the same process. Model oil (dissolving thiophene in the mixture of heptane and toluene) and commercial gasoline were treated by BMIMCu2Cl3 at room temperature. It is found that BMIMCu2Cl3 could remarkably remove sulfur from oil. After six-stage extraction, the S content in the model oil reduces from 650×10-6 to 20×10-6 when the mass ratio of IL/oil is 1∶3. The single stage desulfurization decreases from 37% to 23% with the IL/oil ratio decrease from 1∶2 to 1∶5. It is also shown that the desulfurization ability of BMIMCu2Cl3 from real gasoline is similar to that from model oil. Other components in gasoline have little influence on the desulfurization ability of BMIMCu2Cl3. BMIMCu2Cl3 can be easily separated because of the biphasic systems of IL/oil formation. The polymerization products of olefin in gasoline are not detected in desulfurization. Desulfurization abilities of BMIMZn2Cl5 or Et3NHCu2Cl3 are lower than that of BMIMCu2Cl3. Carbon tetrachloride and toluene were used to regenerate the ionic liquid prepared. The regeneration was conducted at mass ratio IL/solvent of 1∶3 and temperature of 75 ℃ with stirring for 30 min. The regeneration results indicate that the sulfur removal capacity of IL is recovered completely by carbon tetrachloride treatment, but toluene shows poor ability to regenerate BMIMCu2Cl3. CCl4 might be easily seperated from the high boiling point thiophene derivatives absorbed by evaporation or rectification .