Ultrasonic studies of molecular interactions in binary mixtures of formamide with some isomers of butanol at 298.15 K and 308.15 K

Ultrasonic speeds have been measured at 298.15 K and 308.15 K for formamide + 1-butanol or 2-methyl-lpropanol or 2-methyl-2-propanol mixtures and correlated by various correlations like Nomoto's relation, Van Dael's mixing relation and impedance dependence relation. The ultrasonic speed data were further analyzed in terms of Jacobson's free length theory and Schaaffs collision factor theory. Excess isentropic compressibility was calculated from experimental ultrasonic velocity and excess volume data. For an equimolar mixture, excess molar compressibility follows the sequence: 2-methyl-2-propanol < 2-methyl-l-propanol < 1-butanol. The excess molar ultrasonic speed and isentropic compressibility values were also fitted to Redlich-Kister polynomial equation and other properties like molecular association, available volume, free volume, and intermolecular free length were also reported. (C) 2014 Elsevier B.V. All rights reserved.