@article {4027, title = {{\textquoteright}Intermolecular interactions{\textquoteright} in aqueous solutions of three components including lysozyme}, journal = {Fluid Phase Equilibria}, volume = {136}, number = {1-2}, year = {1997}, note = {ISI Document Delivery No.: YR149Times Cited: 5Cited Reference Count: 4614th IUPAC Conference on Chemical Thermodynamics (ICCT 97)AUG 25-30, 1996OSAKA, JAPANInt Union Pure \& Appl Chem, Sci Council Japan, Chem Soc Japan, Japan Soc Calorimetry \& Thermal Anal, Atom Energy Soc Japan}, month = {Nov}, pages = {207-221}, type = {Proceedings Paper}, abstract = {Excess partial molar enthalpies were measured in ternary aqueous solutions, tert-butyl alcohol (TBA)DMSO-H2O, and lysozyme (L)-alcohols (A)-H2O. The solute-solute interactions were evaluated as the derivatives of these data with respect to the mole fraction of a solute. In the water-rich region, where the so-called mixing scheme I is operating in binary aqueous solutions of TEA, DMSO or alcohols, two solutes in TBA-DMSO-H2O seem to modify the hydrogen bond network of H2O in an additive manner. Here, mixing scheme I refers to the way in which a solute (hydrophobic) modifies the molecular organization of H2O. Specifically, a solute enhances the hydrogen bond strength of H2O in its immediate vicinity. On the other hand, the probability of hydrogen bond in the bulk away from a solute is reduced, and it is still high enough, however, to keep the hydrogen bond network connected throughout the entire macroscopic: system. As the composition of solute increases, the hydrogen bond probability in the bulk decreases to the point at which the macroscopic bond connectivity is no longer possible. At this point, a new mixing scheme, II, sets in. For L-A-H2O mixtures at infinite dilution of L, the L-A interaction changes drastically from repulsive: to attractive at the boundary between I and II for binary aqueous alcohols. Moreover, a denatured lysozyme interacts with alcohols more strongly than the native form, and is more repulsive in mixing scheme I and more attractive in IT. This behaviour is shown to be consistent with the alcohol-dependent enthalpy of denaturation of lysozyme found by Velicelebi and Sturtevant [Velicelebi and Sturtevant, Biochem. 18 (1979) 1188-86]. (C) 1997 Elsevier Science B.V.}, keywords = {2-BUTOXYETHANOL, BUTYL ALCOHOL, denaturation of lysozyme, enthalpy of, excess partial molar enthalpies, FREE-ENERGIES, HEAT-CAPACITIES, lysozyme-alcohols-H2O, MIXING SCHEME, PARTIAL MOLAR ENTHALPIES, SOLUTE-SOLUTE INTERACTION, TERT-BUTANOL MIXTURES, tert-butyl alcohol-DMSO-H2O, THERMAL EXPANSIVITIES, VAPOR-PRESSURES, WATER-RICH REGION}, isbn = {0378-3812}, url = {://000071465000020}, author = {Koga,Yoshikata and Westh, P. and Trandum, C. and Haynes, C. A.} } @article {3412, title = {EXCESS PARTIAL MOLAR ENTHALPIES, ENTROPIES, GIBBS ENERGIES, AND VOLUMES IN AQUEOUS DIMETHYLSULFOXIDE}, journal = {Journal of Solution Chemistry}, volume = {24}, number = {1}, year = {1995}, note = {ISI Document Delivery No.: QF279Times Cited: 60Cited Reference Count: 20}, month = {Jan}, pages = {89-102}, type = {Article}, abstract = {The excess partial molar enthalpies, the vapor pressures, and the densities of dimethylsulfoxide (DMSO) - H2O mixtures were measured and the excess partial molar Gibbs energies and the partial molar volumes were calculated for DMSO and for H2O. The values of the excess partial molar Gibbs energies for both DMSO and H2O are negative over the entire composition range. The results for the water-rich region indicated that the presence of DMSO enhances the hydrogen bond network of H2O. Unlike monohydric alcohols, however, the solute-solute interaction is repulsive in terms of the Gibbs energy. This was a result of the fact that the repulsion among solutes in terms of enthalpy surpassed the attraction in terms of entropy. The data in the DMSO-rich region suggest that DMSO molecules form clusters which protect H2O molecules from exposure to the nonpolar alkyl groups of DMSO.}, keywords = {2-BUTOXYETHANOL, 25-DEGREES-C, AQUEOUS DIMETHYLSULFOXIDE, DIMETHYL-SULFOXIDE, ENTROPIES, excess partial molar enthalpies, GIBBS ENERGIES AND VOLUMES, HEAT-CAPACITIES, LIQUID-MIXTURES, MIXING SCHEME, RANGE, SOLUTE-SOLUTE INTERACTION, TRANSITION, WATER-RICH REGION}, isbn = {0095-9782}, url = {://A1995QF27900007}, author = {Lai, J. T. W. and Lau, F. W. and Robb, D. and Westh, P. and Nielsen, G. and Trandum, C. and Hvidt, A. and Koga,Yoshikata} } @article {7112, title = {EXCESS PARTIAL MOLAR ENTHALPIES IN THE WATER-RICH REGION OF THE ISOBUTYRIC ACID - WATER-SYSTEM}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {69}, number = {7}, year = {1991}, note = {ISI Document Delivery No.: FY816Times Cited: 8Cited Reference Count: 24}, month = {Jul}, pages = {1065-1069}, type = {Article}, abstract = {The excess partial molar enthalpies of isobutyric acid (IBA), H(m)E(IBA), and those of H2O, H(m)E(H2O), were measured in aqueous solutions of IBA. The temperature dependence of H(m)E(IBA) at the infinite dilution suggested that the structure enhancement of the solvent H2O by IBA is weaker than those by tert-butanol (TBA) or 2-butoxyethanol (BE). The concentration dependence of H(m)E(IBA), and that of the enthalpic IBA-IBA interaction, N{partial H(m)E(IBA)/partial n(B)}, shows that there are two distinct mixing schemes bounded at about x(B) = 0.03, before reaching the two phase separation. Namely, the IBA-IBA interaction is repulsive below this boundary, while above this boundary it becomes attractive leading eventually to phase separation at a higher concentration. The transition between the two schemes is associated with a peak(negative) anomally in the fourth derivative of the free energy, N2 {partial H-2(m)E(IBA)/partial n(B)2}.}, keywords = {2-BUTOXYETHANOL, CRITICAL SOLUTION TEMPERATURE, excess partial molar enthalpies, EXPONENT, INTERFACIAL-TENSION, ISOBUTYRIC ACID WATER, LIQUID WATER, MIXING SCHEME, TERT-BUTANOL MIXTURES, TRANSITION, TRANSITION IN, ULTRALOW, VICINITY, VISCOSITY}, isbn = {0008-4042}, url = {://A1991FY81600005}, author = {Siu, W. W. Y. and Wong, T. Y. H. and Chao, L. C. F. and Koga,Yoshikata} }