Densities, excess molar volumes, isothermal compressibilities, and isobaric thermal expansivities of the N-methyldiethanolamine (1) + Water (2) system at temperatures between (313 and 363) K and pressures up to 20 MPa

PpT properties in the compressed liquid phase were measured for the system N-methyldiethanolamine (MDEA) (1) + water (2) at temperatures between (313 and 363) K and pressures up to 20 MPa. Densities of MDEA and four gravimetrically prepared mixtures of MDEA (1) + water (2), at x₁ = 0.0369, 0.0607, 0.0893, and 0.1302, were determined using a vibrating tube densimeter. The classical calibration method of the vibrating tube densimeter was used, using nitrogen and water as reference fluids. The uncertainty was estimated to be ±0.2 kg·m^-3 for the measured densities. The densities of each mixture and of MDEA were correlated using a volume explicit equation of six parameters. Isothermal compressibilities and isobaric thermal expansivities were calculated using the sixparameter equation with the correlated parameters obtained for MDEA and for the four mixtures. The uncertainties on these properties were estimated to be ±0.005 GPa^-1 and ±5·10^-7 K^-1, respectively. Excess molar volumes for the mixtures were determined using the measured densities of the mixture and MDEA volumes calculated from the six-parameter equation and water volumes calculated from a multiparameter reference equation of state (EoS). The uncertainty in excess molar volumes was estimated to be ±0.006 cm ³·mol^-1.