Solubilities and Thermodynamic Properties of NH3 in Glycerin and its Derivatives

The solubilities of ammonia (NH3) in glycerin (G) as well as its derivatives were determined at 303.15, 313.15, 323.15, and 333.15 K and pressure scope of 0–570.0 kPa by isochoric saturation method. Three glycerin derivatives include dl-1,2-isopropyli-deneglycerol (GAK), glycerol formal (GF), and 3-methoxy-1,2-propanediol (MP). Henry’s law constants together with thermodynamic property changes of dissolution Gibbs free energy, enthalpy, and entropy during NH3 dissolving were derived by fitting the experimental data. The results showed that the gravimetric solubilities of NH3 in these solvents changes along with the sequence of G > GF > MP > GAK. The increasing pressure or the decreasing temperature led to improvement of the solubility of NH3 in each solvent. The dissolution of NH3 presented as a spontaneous process due to the dissolving enthalpy less than zero at each condition. By comprehensive comparison of dissolving ability, properties, price, and environmental impact between present solvents and other absorbents in the literatures, glycerin was believed as a potential NH3 captures in the industry.