Volumetric, Optical and Spectroscopic Properties of Binary Mixtures of Glycerol with Butanediol Isomers

The presented work is a part of a research study on the volumetric, optical, and spectroscopic properties of binary mixtures containing glycerol with the four isomers of butanediol, namely: 1,2-butanediol or 1,3-butanediol or 1,4-butanediol or 2,3-butanediol. The density and refractive index measurements of pure components and their binary mixtures were carried out at atmospheric pressure and in a temperature range from 293.15 K to 318.15 K. The experimental data were then used to calculate for each system the following derived properties as a function of temperature and glycerol concentration: excess molar volumes, V^E , partial molar volumes, V¯ _i , apparent molar volumes, V_ϕi , partial molar volumes at infinite dilution, V¯i∞ , excess partial molar volume at infinite dilution, Vi¯E∞ , isobaric thermal expansions, α , excess thermal expansions, α^E , and refractive index deviations, Δ n_D . Infrared spectroscopy analysis was also performed at atmospheric temperature and pressure. The experimental data obtained were fitted using the polynomial equation of Redlich-Kister. Excess molar volumes V^E for all the studied systems are negative over the entire composition range and at all the considered temperatures with deviations from ideality increasing with increasing temperature. The calculated molar excess properties were well correlated by the empirical Redlich-Kister polynomial. All measured and calculated properties reveal a significant influence of molecule structure, including the size, shape and position of the component hydroxyl groups. As intended, the infrared spectra of these binary mixtures display a high potential for hydrogen bonding. PC-SAFT EoS was successfully used to adjust the vapor pressure and liquid density of pure fluids, and was used predictively to correctly obtain the density of the mixture. Laplace’s rule was used to predict the refractive index of mixtures.