Thermal stability and vapor-liquid equilibrium of aqueous solutions of choline and tetramethylammonium taurate

Abstract

The thermal degradation of tetramethylammonium taurate and choline taurate and aqueous solutions of these compounds were examined. The thermal degradation products for each of the solid compounds are identified and the data show that the compounds lose less than 1 % of their mass when heating is below 85 °C for 10 h. However, it is difficult to distinguish between the degradation of the compounds and the loss of strongly retained water. The degradation products of the compounds in aqueous solution are also identified and a degradation pathway is proposed. Additionally, the vapor–liquid equilibrium of the compounds in aqueous solutions was measured and the data was fit to the non-random two-liquid (NRTL) model. The data indicate significant deviations from ideality as described by the activity coefficients of the solutions. The results provide insight into the selection of absorber stripping temperatures, the modeling of absorber columns that utilize aqueous ionic absorber fluids, and how these properties are impacted by different cations.