Solute-solute-solvent interactions in dilute aqueous solutions. Microcalorimetric study of isomeric butanediols

The heats of dilution of butane-1,2-diol, butane-1,3-diol, and butane-1,4-diol and of their mixtures were determined at 25°C. The virial enthalpic coefficients of the excess enthalpies of the binary and ternary solutions were evaluated and compared with the literature data for isomeric mono- and polyols. The enthalpic pair interaction coefficients of isomeric diols are positive. The highest value is observed for butane-1,2-diol thus supporting the importance of steric and nearest neighbors effects in the hydration properties of isomeric compounds. Mixed enthalpic coefficients were also determined and discussed.