Dongshun Deng

Vapour–liquid equilibrium measurements and modelling for the ternary system (water + 2-propanol + 1-butyl-3-methylimidazolium acetate)

Vapour–liquid equilibrium (VLE) data were measured for the ternary mixtures of water (1) + 2-propanol (2) + 1-butyl-3-methylimidazolium acetate ([bmim][OAc]) (3). Complete T, x and y data were obtained in a relatively wide range of ionic liquid (IL) mass fractions up to 0.8. The data were correlated by means of NRTL and eNRTL equations with satisfactory results. Using the eNRTL equation, the ternary VLE behaviour was also modelled through correlation of two data sets, in which the mole fraction of 2-propanol on IL-free basis is respectively at 0.1 and 0.98. In this way, the six data sets were reproduced satisfactorily, with root mean square deviations of 1.06 K for temperature and 0.0098 for vapour-phase mole fractions. Owing to the regular distribution of the experimental data, good agreement between experiment and calculation was graphically presented. Effect of the IL on the VLE behaviour of the volatile components was also illustrated.

Solubilities of CO2 in 1-Allyloxy-3-(4-Nonylphenoxy)-2-Propanol Polyoxyethylene Ethers

1-allyloxy-3-(4-nonylphenoxy)-2-propanol polyoxyethylene ethers (ANAPEs), a new type of absorbent, are polymeric surfactants with different adduct numbers. In this work, ANAPEs, including SN-10 with adduct number of 10 and SN-15 with adduct number of 15, were prepared for CO2 absorption using the isochoric saturation method. Densities of the ANAPEs at atmospheric pressure were measured by a 5.567 ± 0.004 cm3 pycnometer, which decreased with increased temperature. Solubility data of CO2 in ANAPEs were measured within the pressure range of 0 – 600.0 kPa and temperature range of 303.15 – 323.15 K at 10 K intervals and could be calculated on the basis of experimental data of p, xCO2 and bCO2. The solubility of CO2 in absorbents increased linearly with increasing pressure and decreased with increasing temperature at all the pressures. The solubility of CO2 in SN-15 is the highest at all temperatures, but almost the same with SN-10 at 303.15 K over pressures (p < 350kPa), which indicates physical dissolution process. Henry’s constants were determined from solubility data. With increasing temperature, Henry’s constants increased. Thermodynamics of CO2 absorption were calculated including enthalpy, entropy, and Gibbs energy. The absolute value of ΔsolH based on Hx of SN-15 is largest at 303.15 K and indicates stronger SN-15/CO2 interactions, consistent with solubility of CO2 based on Hx. The negative enthalpy demonstrated exothermic process, which means the dissolution of CO2 in ANAPEs is favourable enthalpically. The ΔsolG shows positive value.