Gas solubilities in deep eutectic solvents

Deep eutectic solvents (DES) are competitive solvents for the reversible capture of carbon dioxide and sulfur dioxide. They are 'green', i.e., friendly to the environment and inexpensive to produce. The solubilities of these gases in a variety of DES have been collected from the literature and reviewed and are described by means of the capacity (moles gas per kg solvent) at a given temperature and partial pressure of the gas, and the corresponding Henry's law constant. The saturation molalities at 0.1 MPa partial gas pressure for the solubility of CO2 in the commonly used choline chloride-based DES at 313.15 K are between 0.2 and 0.7 mol kg(-1). The corresponding values for SO2 are some order of magnitude larger. The gas solubility increases linearly with the partial pressure but diminishes with increasing temperatures, the negative enthalpy of solution showing the process to be exothermic.