Interactions in aqueous solutions of urea and alcohols. Excess enthalpies at 25°C

The heats of dilution of ternary aqueous solutions of urea and alcohols have been determined at 25°C. From the experimental data the values of the excess enthalpies H_ij^E and of the pair enthalpy interaction coefficients h_ij have been evaluated and compared with the data reported in the literature. The values of the h_ij coefficients at 25°C are all positive and depend on the length and branching of the alkyl chain of the alcohols. The results are discussed in terms of the effects of a chaotropic agent”, as urea, on the cospheres of mainly hydrophobic such as alcohols.