Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The solubility of ionic liquid (IL) 1-butyl-3-methylimidazolium acetate ([Bmim]Ac) in supercritical carbon dioxide (scCO2) with cosolvents, including ethanol, acetone, dimethylsulfoxide (DMSO) and acetonitrile, was determined respectively at 40 C, 50 C, 60 C and pressure up to 15.0 MPa. The results showed that the addition of cosolvents has a significant effect on the solubility of [Bmim]Ac in scCO2. The ability of different cosolvents to enhance the solubility of [Bmim]Ac in scCO2 are in the following order: ethanol greater than DMSO greater than acetone greater than acetonitrile. The solubility of [Bmim]Ac in scCO2 / cosolvent mixture increased dramatically as the cosolvent concentration exceeded 20.0 mol%. The effect of temperature on solubility is more complicated: The solubility of [Bmim]Ac in scCO2 / cosolvent increased slowly when using ethanol as cosolvent, but decreased slowly when using acetone or acetonitrile as cosolvent, and increased first and then decreased when using DMSO as cosolvent as the temperature increased from (40 to 50, 60) . Moreover, the values of solubility increased as the pressure increased from (8 to 15) MPa. The increase tendency in the high pressure area is more obvious. The maximum solubility is 3.66x10-4 mol%, which can be obtained when using 26.0 mol% ethanol at 60 , 14.55 MPa and the minimum solubility is 1.89x10-6 mol%, which can be obtained when using 10.5 mol% DMSO at 40 , 9.93 MPa. The modified Christal equation was used to correlate the solubility data, and the average absolute relative deviations are in the range of 4.36%-14.35%, the maximum correlation accuracy is obtained when using ethanol as cosolvent, a minimum value for system using DMSO as cosolvent.