Influence of alkyl group on interactions between carboxylic acid and acetonitrile at different temperatures

•Density and sound velocity for the liquid mixtures were measured.•Excess properties were calculated and correlated using Redlich–Kister equation.•The results were discussed in term of intermolecular interactions.•The effect of temperature on density and sound velocity were discussed.•The effect of concentration on density and sound velocity were discussed. In this paper, the influence of alkyl group as well as temperature on interactions between carboxylic acid and acetonitrile were examined using thermodynamics technique. The carboxylic acid used in this study was acetic acid and propionic acid. To explore the utility of carboxylic acid and acetonitrile, we have carried out the interaction studies of carboxylic acid with acetonitrile using density, ρ, and sound velocity, u, measurements of acetic acid, propionic acid, acetonitrile, and their binary systems {acetic acid or propionic acid (x1)+acetonitrile (x2)} as function of temperature. The excess molar volumes, VmE, isentropic compressibility, κs, and deviation in isentropic compressibility, Δκs, were calculated from thermophysical properties, respectively which provide information about the intermolecular interactions as well as the influence alkyl group and temperatures that occurs between carboxylic acid and acetonitrile mixtures. The Redlich–Kister polynomial equation was used to fit the thermodynamics properties to test the experimental data. These results are useful for describing the intermolecular interactions; developing structure–property correlation and molecular modeling that exist between the carboxylic acid and acetonitrile mixtures.