The enthalpies of transfer, Delta H-t(H), of the solutes from pure solvent A to mixtures of A and a second solvent B were studied by isothermal titration calorimetry and analysed in terms of the new extended solvation theory. These data are considered in terms of the new developed solvation theory including variable (alpha n + beta N), the net effect of the solute Oil the solvent-solvent bonding and is positive if there is a net breaking or weakening of solvent-solvent bonds. (C) 2008 Elsevier B.V. All rights reserved.