Measurement and modeling the excess molar properties of binary mixtures of {[C6mim][BF4] + 3-amino-1-propanol} and {[C6mim][BF4] + isobutanol}: Application of Prigogine–Flory–Patterson theory

Abstract

In this work, densities, ρ, and viscosities, η, of pure 1-hexyl-3-methylimidazoliumtetrafluoro borate {[C6mim][BF4]}, 3-amino-1-propanol (AP), and isobutanol, along with their binary mixtures of {x1[C6mim][BF4]+x2AP} and {x1[C6mim][BF4]+x2isobutanol} were measured over entire composition range at ambient pressure (81.5kPa) and in the temperature range of (303.15 to 338.15)K. The excess molar volume, VmE, thermal expansion coefficient, α, and its excess value, αE, isothermal coefficient of excess molar enthalpy, (∂HmE/∂p)T,x, and viscosity deviation, Δη, for both of the mixtures were calculated from the experimental values of densities and viscosities. The values of VmE for binary mixture of {x1[C6mim][BF4]+x2AP} shows a S-shaped dependence on composition with positive values in the [C6mim][BF4] rich-region and negative values at the opposite extreme, and increase with increasing temperature. This quantity is negative for binary mixture of {x1[C6mim][BF4]+x2isobutanol} in the entire composition range and increases with increasing temperature. Viscosity deviations, Δη, are negative over the entire composition range and decrease with increasing temperature for both of the mixtures. These data were correlated by Treszczanowiczb–Benson and Redlich–Kister equations, and the fitting parameters and standard deviations were determined. The Prigogine–Flory–Patterson theory has been used to correlate the excess molar volumes of the mixtures.