Measurement of\nVapor–Liquid Equilibrium Data\nfor Binary Systems CO<sub>2</sub> + Ethyl Propionate, Methyl Propionate,\nEthyl Acetate, and Ethyl Isobutyrate at 253.15 K

In order to improve the decarbonization capacity of the\nabsorbent\nin the syngas purification process in industry, selecting and developing\nmore efficient physical solvents has become a breakthrough direction.\nConsidering that ester solvents have great potential for absorbing\nCO<sub>2</sub>, in this work, vapor–liquid equilibrium (VLE)\ndata were measured for the binary system of CO<sub>2</sub> + ethyl\npropionate, methyl propionate, ethyl acetate, and ethyl isobutyrate\nat 253.15 K. Herein, the operating pressure ranges from 0.3 to 1.7\nMPa. The experimental data were correlated by Peng–Robinson\n(PR) and Soave–Redlich–Kwong (SRK) equations of state\nwith van der Waals (vdW) mixing rules. Among the aforementioned equations,\nthe PR equation of state correlates the experimental data better above\n1.2 MPa. Moreover, it can be found that ethyl acetate has the best\nCO<sub>2</sub> absorption performance, followed by methyl propionate,\nethyl propionate, and ethyl isobutyrate. In addition, the average\nabsolute relative deviations of the molar fractions of CO<sub>2</sub> in the vapor phase and measured pressures were calculated for each\nsystem. As a result, the overall deviations were less than 0.02% and\n4%, respectively, indicating that the measured experimental values\nare stable and reliable. This work will not only provide a reference\nfor screening efficient CO<sub>2</sub> absorption solvents but also\nprovide the basic thermodynamic data for the syngas purification process.