Solubility of carbon dioxide in alkylcarbonates and lactones

Abstract

The solubility of carbon dioxide in γ-butyrolactone (BL), caprolactone (CL), propylene carbonate (PC), ethylene carbonate (EC), dimethylcarbonate (DMC), diethylcarbonate (DEC), and mixtures of these components has been determined at temperatures from 275 to 333 K at atmospheric pressure. The Henry's law constant (kH) for the dissolution of CO2 in these solvents has been deduced from the solubility data. The value of kH increases in the following order: DEC < DMC < PC < CL < BL < EC, which is identical to the order of the Hildebrand parameters (δ) of the corresponding solvents. The accuracy of classical theories for predicting gas solubilities in liquids has been examined. The best results are given by the Vilcu–Perisamu equation, which is derived from the Scatchard–Hildebrand theory but takes into account the polarizability of the solute and the permittivity of the solvent. A modified form of the Prausnitz and Shair equation is proposed to estimate the solubility of nonpolar molecules in strongly dipolar solvents. This equation fits the experimental data with improved precision.Key words: alkylcarbonate, lactone, carbon dioxide, liquid–gas equilibrium, Henry's law, Hildebrand parameter.