서강대학교

초록/요약

In this study, three kinds of [BETI] anion and [Tf2N] anionic ionic liquids were selected for high pressure CO2 solubility. Solubility data were obtained by measuring the bubble point pressure of the mixture using a variable volume view cell. Experimental conditions were set at 10 K interval from 303.15 K to 373.15 K. The new solubility database for six ionic liquids were constructed by this work, and it is confirmed that CO2 absorption capacity is better in order of [HMIM] [BETI], [BMIM] [BETI], [EMIM] [BETI], [BVMIM] [Tf2N], [P4441] [Tf2N], and [N4222] [Tf2N]. From experimental data, thermodynamic modeling was correlated through Peng-Robinson equation of state and van der Waals one fluid mixing rule to predict CO2 solubility for ionic liquids at various temperature and composition ranges. The critical properties and acentric factor of the ionic liquid were calculated using the modified Lydersen-Joback-Reid method. The overall average absolute deviation of pressure (AAD-P) is estimated to be less than 2% of the total temperature and this means that the modeling equation track experimental data. Expanded uncertainty was obtained for each binary system according to the National Institute of Standards and Technology (NIST) manual, and the average value for the entire temperature range is about 0.1 MPa, ensuring the reliability of the experimental data. Also, the trend of CO2 absorption capacity according to the change of molecular structure of ionic liquid was analyzed. As a result, it was confirmed that the longer the cationic alkyl chain length of the ionic liquid, the more the fluoroalkyl group of the anion absorbs the more CO2. Keywords: CO2 solubility, Ionic liquids, PR-EoS, [BETI] anion, electrochemical