High-pressure densities of 2-(dimethylamino) ethanol and 2-(diethylamino) ethanol: Measurement and modeling with new modified Tait and PC-SAFT equations of state

Abstract

New experimental high-temperature, high-pressure (HTHP) density data of two alkanolamines, namely 2-(dimethylamino) ethanol and 2-(diethylamino) ethanol was measured in a wide range of temperatures (293.15–473.15 K) and pressures (0.1–40 MPa). The density measurements were performed using an Anton Paar high-pressure vibrating tube densimeter. The combined expanded uncertainty in the reported densities, at a 95% confidence level with taking into account the impurities of materials and apparatus specification was 1kg·m−3. The density and speed of sound at ambient pressure (81.5 kPa) and temperatures (293.15–343.15 K) were also measured. The experimental density data were correlated, as a function of pressure and temperature, using the new modified Tait equation, and derived properties including thermal expansion coefficient (αP) and isothermal compressibility (κT) were calculated. The modeling results in this work have been obtained by using the perturbed-chain statistical associating fluid theory equation of state (PC-SAFT EOS). The parameters of the PC-SAFT equation of state (EOS), for pure compounds, were firmly determined by fitting the equation to the liquid PρT experimental data. With these parameters, thermodynamic properties such as thermal expansion coefficient (αP), isothermal compressibility (κT), isobaric heat capacity (CP), and speed of sound (u) were calculated. Good agreement between the results and experimental data and derived properties represented the modeling accuracy with the obtained parameters.