Temperature and composition dependence of excess Gibbs energy in the system of tetraglyme (1) + decane (2): Evaluation by simultaneous correlation of limiting activity coefficients, liquid-liquid equilibrium, and calorimetric data

摘要

Properties related to vapor-liquid and liquid-liquid equilibria in the binary system of tetraglyme (1) + alkane (2) were measured, collected from literature, and subsequently simultaneously correlated using the Redlich-Kister equation and basic thermodynamic relationships. The Inert Gas Stripping method was used for measurement of limiting activity coefficients of alkanes (pentane, hexane, heptane, and octane) in tetraglyme in the temperature interval from 288.15 to 313.15 K. The limiting activity coefficient of decane in tetraglyme was obtained by extrapolation of these experimental data in a homologous line of alkanes. Liquid-liquid equilibria were measured by direct analytical and turbidity methods. Excess enthalpy and excess heat capacity data were collected from the literature. As the studied system shows an upper critical Solubility temperature and a "W-shape" composition dependence of the excess heat capacity, a high number, namely 17, of correlation equation parameters were needed for a precise description of the temperature and composition dependence of the excess Gibbs energy and related physical properties.