Measurement of CO2 Solubility in Ionic Liquids: [BMP][Tf2N] and [BMP][MeSO4] by Measuring Bubble-Point Pressure

Abstract

This paper presents the bubble-point pressure data of CO2 in ionic liquids 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMP][Tf2N]) and 1-butyl-1-methylpyrrolidinium methylsulfate ([BMP][MeSO4]). In our research, the high-pressure phase behavior of carbon dioxide in [BMP][Tf2N] and [BMP][MeSO4] were observed at pressure up to about 100 MPa in a temperature range from (303.15 to 373.15) K in 10 K intervals by using a high-pressure variable-volume view cell. To investigate the effect of different anion on the solubility of CO2 in the [BMP] cation based ionic liquids, we compared three [BMP] cation based systems; [BMP][Tf2N] +, [BMP][TfO] +, and [BMP][MeSO4] + CO2. In all systems, at lower mole fraction of CO2 (below 0.3), the solubility is approximately the same, however above 0.3 mol fraction, the ration between pressure and CO2 mol fraction decreases sharply. Although these experiments have used the same cation, it would appear that the ratio decreases more sharply as the alkyl group...