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

Abstract

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 CO 2 absorption using the isochoric saturation method. Densities of the ANAPEs at atmospheric pressure were measured by a 5.567 ± 0.004 cm 3 pycnometer, which decreased with increased temperature. Solubility data of CO 2 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, x CO2 and b CO2 . The solubility of CO 2 in absorbents increased linearly with increasing pressure and decreased with increasing temperature at all the pressures. The solubility of CO 2 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 CO 2 absorption were calculated including enthalpy, entropy, and Gibbs energy. The absolute value of Δ sol H based on H x of SN-15 is largest at 303.15 K and indicates stronger SN-15/CO 2 interactions, consistent with solubility of CO 2 based on H x . The negative enthalpy demonstrated exothermic process, which means the dissolution of CO 2 in ANAPEs is favourable enthalpically. The Δ sol G shows positive value.

Solubility Measurement and Thermodynamic Properties Calculation for Several CO2 + Ether Absorbent Systems

“…In the authors’ previous work, CO 2 solubilities in three kinds of polymers with ether groups were measured at 273.15–303.15 K and 0–1.2 MPa. In addition, various solubility data of CO 2 in other physical solvents with ester, hydroxyl, carbonyl groups and so on, were determined in the literature. − …”