Experimental study and modelling using the ERAS-Model of the excess molar volume of acetonitrile–alkanol mixtures at different temperatures and atmospheric pressure

Densities of {(1−x)CH3(CH2)n−1OH + xCH3CN} for n=1, 2, 3 or 4 have been determined as a function of composition at 288.15, 293.15, 298.15 and 303.15 K at atmospheric pressure using a vibrating-tube densimeter (Anton Paar DMA 4500, resolution 1×10−5 g cm−3). Excess molar volumes were calculated. The VmE values were negative for acetonitrile–methanol mixtures and sigmoid for acetonitrile–alkanols (C2–C4) mixtures over the complete mole fraction range. VmE values increase in a positive direction with increase in chain length of the alkanols and with the temperature. The Extended Real Associated Solution Model (ERAS-Model) calculations allowing for self-association for the alkanols and complex formation between acetonitrile and alkanols have been used to correlate experimental data. The model is able to reproduce the asymmetrical VmE behavior of the studied systems, although agreement between theoretical and experimental values is less satisfactory for some concentration ranges.