Ultrasound speeds and molar isentropic compressions of (3-ethoxypropane-1-amine + water) mixtures from T = (283.15 to 303.15) K

•Ultrasound speeds of 53 aqueous mixtures of 3-ethoxypropane-1-amine were experimentally determined.•Excess molar and partial molar isentropic compressions were derived.•Frontiers of different molecular aggregation regions were found.•Limiting partial molar isentropic compression and isobaric expansions were interpreted in terms of hydration features.

Alkoxyamines containing two hydrophilic groups with great affinity to water are multipurpose compounds with important applications, either on theoretical or practical grounds. The thermodynamic characterization of aqueous mixtures of these compounds is scant. Ultrasound speed measurements have been made in 53 mixtures of the aqueous ethoxypropane-1-amine binary system, across the entire composition range and temperatures between T = (283.15 and 303.15) K, at atmospheric pressure. By combining ultrasound speed and density data, values of the isentropic compressibility were derived. Excess molar isentropic compressions were estimated and analytically fitted to Redlich–Kister polynomial equations. Excess partial molar quantities were then calculated including their limiting values, which were obtained from the Redlich–Kister fitting coefficients. The temperature dependences of limiting partial molar isentropic compressions and isobaric expansions were also scrutinized. Compressibility changes associated with different patterns of aggregation and hydration over the whole composition range are identified.

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