Molecular interaction study using density, viscosity, speed of sound and FT-IR in 2-methyl-2-butanol + alkoxyethanols: Experimental and modelling approach

In this article, the intermolecular interactions in the binary liquid mixtures of 2-methyl-2-butanol with alkoxyethanols viz., 2-ethoxyethanol, 2-propoxyethanol and 2-butoxyethanol have been interpreted using thermophysical properties. Density ($\rho$), viscosity ($\eta$) and speed of sound (u) of pure components and their binary mixtures have been measured over the entire range of composition at 298.15, 303.15 and 308.15 K and at pressure p = 0.10 MPa. The experimental data were used to calculate the thermophysical properties such as excess molar volume ($V_m^E$), excess molar isentropic compressibility ($K_{s,m}^E$), excess speed of sound ($u^E$), deviation in viscosity (Δ$\eta$) and excess Gibbs free energy of activation for viscous flow ($\Delta G^{\ast E}$). The changes in these properties with composition and temperature of the liquid mixtures were discussed in terms of intermolecular interactions. Also, the effect of increase in alkyl chain length of alkoxyethanol molecule on these properties has been studied. The excess functions and their deviations have been correlated using Redlich-Kister type polynomial equation. The experimentally measured values of viscosities have been correlated with various semi-empirical relations such as Grunberg-Nissan, Tamura-Kurata, Hind et al., Katti-Chaudhri, McAllister’s two parameter model, Heric-Brewer and McAllister’s three parameter model. Apart from this, Prigogine-Flory-Patterson (PFP) theory has been used for the estimation of $V_m^E$ values for studied binary mixtures. FT-IR spectra of these liquid mixtures have also been studied.