Molecular interaction in the binary mixtures of tetrahydrofuran and 1,4-dioxane with methanol. New UNIFAC-VISCO interaction parameters for cyclic ethers

Abstract

Densities (ρ), viscosities (η), and refractive indices (nD) have been measured for binary organic systems of methanol (MeOH) with tetrahydrofuran (THF) and 1,4-dioxane (DXN) over the entire range of composition, and at different temperatures between 298.15 and 318.15 K. From the data of ρ, η, and nD, properties such as excess molar volume, VmE, thermal expansivity, α, excess thermal expansivity, αE, deviation in viscosity, Δη, free energy for the activation of viscous flow, ΔG≠, and its excess, ΔG≠E, and deviation in refractive index, ΔnD, were derived. Measured ρ, η, and nD were correlated with the concentration-dependent polynomial equations, and their excess properties were fitted with Redlich-Kister type equations. Temperature-dependent Jouyban-Acree model was also used to correlate the experimental ρ and η. Negative values of VmE and Δη, and ΔG≠E lead to reveal that the effect of cross hydrogen bonding plays a significant role in both the systems of THF + MeOH and DXN + MeOH. Finally, six new pairs of group–group interaction parameters, αnm, were determined for these cyclic ethers, which can be utilized in extending further the applicability of UNIFAC-VISCO model.