https://doi.org/10.15255/KUI.2017.004
Published: Kem. Ind. 66 (5-6) (2017) 249–254
Paper reference number: KUI-04/2017
Paper type: Original scientific paper
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Solubilities of CO2 in 1-Allyloxy-3-(4-Nonylphenoxy)-2-Propanol Polyoxyethylene Ethers

Q. N. Wang, H. F. Shan, G. H. Li, Y. F. Chen, D. S. Deng and N. Ai

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 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, x_CO2 and b_CO2. 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 Δ_solH based on H_x of SN-15 is largest at 303.15 K and indicates stronger SN-15/CO₂ interactions, consistent with solubility of CO₂ based on H_x. The negative enthalpy demonstrated exothermic process, which means the dissolution of CO₂ in ANAPEs is favourable enthalpically. The Δ_solG shows positive value.

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Keywords

ionic liquids, solubility, Henry's law constant, thermodynamics, Gibbs energy