Predictive Framework for Estimating Dipolarity/Polarizability of Binary Nonpolar-Polar Mixtures with Relative Normalized Absorption Wavelength and Gas-Phase Dipole Moment

A predictive framework is proposed for estimating the dipolarity/polarizability (Ï∗) values of binary mixtures via the relative normalized maximum absorption wavelength (Î"λmixN) of an indicator (N,N-dimethyl-4-nitroaniline) in the pure liquids and the pure component gas-phase dipole moments (μ). New spectroscopic measurements of 13 nonpolar (1)-polar (2) liquid mixtures are reported and local composition was used to correlate variations of Î"λmixN values with mole fraction, x₂. The resulting multivariate linear relationship in x₂ and μ allowed data correlation and was applied to prediction of Ï∗ of (i) ten additional nonpolar-polar mixtures at temperatures of (15 to 45) °C, (ii) nine polar-polar mixtures, (iii) six CO₂-expanded solvent mixtures, and (iv) five molecular solvent-ionic liquid mixtures and was found to give an overall deviation of 8.9% in Ï∗. The predictive framework was applied to the dipolarity/polarizability scales of Effenberger-Würthner and Catalán for 16 polar-polar liquid mixtures and was found to give a maximum deviation of 9.6%. The predictive framework is widely applicable to chemical systems and requires only pure component Ï∗ and gas-phase dipole moment values to estimate the dipolarity/polarizability of solvent mixtures.