@article {2302,
	title = {Experimental determination of the third derivative of G. I. Enthalpic interaction},
	journal = {Journal of Chemical Physics},
	volume = {129},
	number = {21},
	year = {2008},
	note = {ISI Document Delivery No.: 379XWTimes Cited: 2Cited Reference Count: 19Westh, Peter Inaba, Akira Koga, Yoshikata},
	month = {Dec},
	pages = {4},
	type = {Article},
	abstract = {The solute (i)-solute interaction in terms of enthalpy, H-i-i(E)=N(partial derivative H-2(E)/partial derivative n(i)(2))=(1-x(i))(partial derivative H-2(E)/partial derivative n(i)partial derivative x(i)), the third derivative of G, was experimentally determined using a Thermal Activity Monitor isothermal titration calorimeter for aqueous solutions of 2-butoxyethanol (BE) and 1-propanol (1P). This was done using both calorimetric reference and sample vessels actively. We simultaneously titrate small and exactly equal amounts of solute i (=BE or 1P) into both cells which contain the binary mixtures at an average mole fraction, x(i), which differs by a small amount Delta x(i). The appropriate amount of titrant delta n(i) was chosen so that the quotient (delta H-E/delta n(i)) can be approximated as (partial derivative H-E/partial derivative n(i)), and so that the scatter of the results is reasonable. delta H-E is the thermal response from an individual cell on titration, and we measure directly the difference in the thermal response between the two cells, Delta(delta H-E). The resulting quotient, Delta(delta H-E)/delta n(i)/Delta x(i), can be approximated as (partial derivative H-2(E)/partial derivative n(i)partial derivative x(i)) and hence provides a direct experimental avenue for the enthalpy interaction function. We varied the value of Delta x(i) to seek its appropriate size. Since H-E contains the first derivative of G with respect to T, the result is the third derivative quantity. Thus we present here a third derivative quantity directly determined experimentally for the first time.},
	keywords = {AQUEOUS-SOLUTIONS, calorimetry, DYNAMICS, enthalpy, fluctuations, H2O, HOFMEISTER SERIES, LIQUID MIXTURES, MOLECULAR-ORGANIZATION, organic compounds, SOLVATION, WATER},
	isbn = {0021-9606},
	url = {<Go to ISI>://000261430900001},
	author = {Westh, P. and Inaba, A. and Koga,Yoshikata}
}
@article {2129,
	title = {Mixing schemes in a urea-H2O system: A differential approach in solution thermodynamics},
	journal = {Journal of Physical Chemistry B},
	volume = {112},
	number = {36},
	year = {2008},
	note = {ISI Document Delivery No.: 345EVTimes Cited: 5Cited Reference Count: 29Koga, Yoshikata Miyazaki, Yuji Nagano, Yatsuhisa Inaba, Akira},
	month = {Sep},
	pages = {11341-11346},
	type = {Article},
	abstract = {The excess partial molar enthalpies of urea (UR), H-UR(E), were experimentally determined in UR-H2O at 25 degrees C. The H-UR(E) data were determined accurately and in small increments in the mole fraction of UR, X-UR, up to X-UR approximate to 0.22. Hence it was possible to evaluate one more X-UR-derivative graphically Without resorting to any fitting function, and the model-fi-ee UR-UR enthalpic interaction, H{\textquoteright}U{\textquoteright}-R-uR, was calculated. Using previous data for the excess chemical potential, mu(E)(UR), the entropy analogue, S-UR(E)-UR. was also calculated. The X-UR-dependences of both H-UR(E)-UR and S-UR(E)-UR indicate that there is a boundary at X-UR approximate to 0.09 at which the aggregation nature of urea changes. Front the results of our earlier works, we suggest that a few UR molecules aggregate at X-UR approximate to 0.09, while the integrity of H2O is retained at least up to X-UR approximate to 0.20. Together with the findings from our previous studies, we suggest that in the concentration range X-UR < 0.22, UR or its aggregate form hydrogen bonds to the H2O network, reducing the degree of fluctuation characteristic to liquid H2O. However, up to at least X-UR = 0.20 the hydrogen bond network remains intact. Above X-UR approximate to 0.22, the integrity of H2O is likely be lost. Thus, in discussing the effect of urea on H2O and in relating it to the Structure and function of biopolymers in aqueous solutions, the concentration region in question must be specified.},
	keywords = {25-DEGREES-C, AQUEOUS UREA, DYNAMICS, ENTHALPIES, H2O, LIQUID WATER, MOLECULAR-ORGANIZATION, NUCLEAR-MAGNETIC-RESONANCE, POTASSIUM, WATER-STRUCTURE},
	isbn = {1520-6106},
	url = {<Go to ISI>://000258979800023},
	author = {Koga,Yoshikata and Miyazaki, Y. and Nagano, Y. and Inaba, A.}
}
@article {1507,
	title = {Anomalous dynamic behavior of ions and water molecules in dilute aqueous solution of 1-butyl-3-methylimidazolium bromide studied by NMR},
	journal = {Chemical Physics Letters},
	volume = {427},
	number = {1-3},
	year = {2006},
	note = {ISI Document Delivery No.: 073OUTimes Cited: 4Cited Reference Count: 18Nakakoshi, Masamichi Ishihara, Shinji Utsumi, Hiroaki Seki, Hiroko Koga, Yoshikata Nishikawa, Keiko},
	month = {Aug},
	pages = {87-90},
	type = {Article},
	abstract = {Dynamic properties of 1-butyl-3-methylimidazolium bromide ([bmim]Br) in D2O were investigated by NMR. The diffusion coefficients of [bmim](divided by)and HDO were determined separately by the pulse field gradient method. The dynamics of Br- was estimated by the half-widths of the signals of Br-81-NMR. The results indicate that an anomalous dynamics, especially for [bmim](divided by), is evident in the region below similar to 0.1 M (0.0019 in the mole fraction of [bmim]Br). For [bmim](divided by) and HDO, maxima appeared in the curves of the diffusion coefficients plotted against the concentration. The relaxation time, T-2, for Br- showed a break in slope at this composition. Probable interpretations on these findings are presented. (c) 2006 Elsevier B.V. All rights reserved.},
	keywords = {1-PROPANOL, DIFFUSION, ELECTROLYTES, H2O, LIQUIDS, MIXTURES, SOLVENTS, SPECTROSCOPY},
	isbn = {0009-2614},
	url = {<Go to ISI>://000239753300018},
	author = {Nakakoshi, M. and Ishihara, S. and Utsumi, H. and Seki, H. and Koga,Yoshikata and Nishikawa, K.}
}
@article {1258,
	title = {Fluctuation functions in aqueous NaCl and urea},
	journal = {Journal of Physical Chemistry B},
	volume = {109},
	number = {35},
	year = {2005},
	note = {ISI Document Delivery No.: 961UNTimes Cited: 4Cited Reference Count: 30},
	month = {Sep},
	pages = {16886-16890},
	type = {Article},
	abstract = {We earlier devised a set of fluctuation functions that provide relative qualitative differences of the amplitude (intensity) and the wavelength (extensity) of fluctuations in entropy and volume and the entropy-volume cross fluctuations. We discuss the mixing schemes in aqueous NaCl and urea using these fluctuation functions. Our earlier studies by using the second and third derivatives of Gibbs energy indicated that their effects on H2O are qualitatively different. An NaCl hydrates 7.5 molecules of H2O but leaves the bulk H2O away from the hydration shell unperturbed. Urea, on the other hand, connects onto the hydrogen bond network of H2O but retards the degree of fluctuation inherent in H2O. The behavior of the fluctuation functions calculated here are consistent with the above mixing schemes. Furthermore, urea was found to reduce the wavelength of fluctuation more strongly than NaCl.},
	keywords = {25-DEGREES-C, H2O, LIQUID WATER, MODEL, PARTIAL MOLAR FLUCTUATIONS, PERCOLATION, SODIUM-CHLORIDE, SYSTEMS, VOLUMETRIC PROPERTIES},
	isbn = {1520-6106},
	url = {<Go to ISI>://000231687400045},
	author = {Siu, D. and Koga,Yoshikata}
}
@article {1227,
	title = {Hydration number of glycine in aqueous solution: An experimental estimate},
	journal = {Journal of Chemical Physics},
	volume = {123},
	number = {23},
	year = {2005},
	note = {ISI Document Delivery No.: 996ADTimes Cited: 6Cited Reference Count: 31},
	month = {Dec},
	pages = {6},
	type = {Article},
	abstract = {An experimental estimate of hydration number, N-H, of glycine in aqueous solution is given by using the calorimetric methodology developed by us earlier, which is briefly reviewed. We found N-H to be 7 +/- 0.6 for glycine presumably in the zwitter ion form, 10 +/- 1 for sodium glycinate, and 5 +/- 0.4 for glycine hydrochloride. Both glycine and sodium glycinate seem to work purely as a hydration center without altering the nature of the bulk H2O away from the hydration shell. Glycine hydrochloride, in addition to the role of hydration center, seems also to act as a typical hydrophilic species such as polyols, urea, or polyethylene glycols. Hence, the effect of the latter on H2O is of a long range, like other hydrophilic species. (c) 2005 American Institute of Physics.},
	keywords = {25-DEGREES-C, fluctuations, H2O, INTRAMOLECULAR PROTON-TRANSFER, MIXING SCHEMES, MOLECULAR-ORGANIZATION, NONELECTROLYTES, PARTIAL MOLAR ENTHALPIES, TAUTOMERIZATION, WATER},
	isbn = {0021-9606},
	url = {<Go to ISI>://000234145900026},
	author = {Parsons, M. T. and Koga,Yoshikata}
}
@article {901,
	title = {Mixing schemes in ionic liquid-H2O systems: A thermodynamic study},
	journal = {Journal of Physical Chemistry B},
	volume = {108},
	number = {50},
	year = {2004},
	note = {ISI Document Delivery No.: 879CXTimes Cited: 78Cited Reference Count: 33},
	month = {Dec},
	pages = {19451-19457},
	type = {Article},
	abstract = {We studied the hydration characteristics of room-temperature ionic liquids (IL). We experimentally determined the excess chemical potentials, mu(i)(E), the excess partial molar enthalpies, H-i(E), and the excess partial molar entropies S-i(E) in IL-H2O systems at 25 degreesC. The ionic liquids studied were 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) and the iodide ([bmim]l). From these data, the excess (integral) molar enthalpy and entropy, H-m(E) and S-m(E), and the IL-IL enthalpic interaction, H-IL-IL(E), were calculated. Using these thermodynamic data, we deduced the mixing schemes, or the "solution structures", of IL-H2O systems. At infinite dilution IL dissociates in H2O, but the subsequent hydration is much weaker than for NaCl. As the concentration of IL increases, [bmim]l ions and the counteranions begin to attract each other up to a threshold mole fraction, x(IL) = 0.015 for [bmim]BF4 and 0.013 for [bmim]l. At still higher mole fractions, IL ions start to organize themselves, directly or in an H2O-Mediated manner. Eventually for x(IL) > 0.5-0.6, IL molecules form clusters of their own kind, as in their pure states. We show tha HI-L-IL, a third derivative of G, provided finer details than H-i(E) and S-i(E) second derivatives, which in turn gave more detailed information than H-m(E) and S-m(E), first derivative quantities.},
	keywords = {25-DEGREES-C, AQUEOUS SODIUM-CHLORIDE, ENTHALPIES, GLYCEROL, H2O, METHANOL, MIXTURES, MOLECULAR-ORGANIZATION, SOLVENTS, WATER},
	isbn = {1520-6106},
	url = {<Go to ISI>://000225695100058},
	author = {Katayanagi, H. and Nishikawa, K. and Shimozaki, H. and Miki, K. and Westh, P. and Koga,Yoshikata}
}
@article {709,
	title = {Excess chemical potentials and partial molar enthalpies in aqueous 1,2-and 1,3-propanediols at 25 degrees C},
	journal = {Journal of Solution Chemistry},
	volume = {32},
	number = {2},
	year = {2003},
	note = {ISI Document Delivery No.: 661CMTimes Cited: 4Cited Reference Count: 24},
	month = {Feb},
	pages = {137-153},
	type = {Article},
	abstract = {Excess chemical potentials and excess partial molar enthalpies of 1,2- and 1,3-propanediols ( abbreviated as 12P and 13P), mu(i)(E), and H-i(E) ( i = 12P or 13P) were determined in the respective binary aqueous solutions at 25degreesC. For both systems, the values of mu(i)(E) are almost zero, within +/-0.4 kJ-mol(-1). However, the excess partial molar enthalpies, H-i(E) show a sharp mole fraction dependence in the water-rich region. Thus, the systems are highly nonideal, in spite of almost zero mu(i)(E). Namely, the enthalpy-entropy compensation is almost complete. From the slopes of the HE i against the respective mole fraction x(i) we obtain the enthalpic interaction functions between solutes, H-i-i(E), ( i = 12P or 13P). Using these quantities and comparing them with the equivalent quantities for binary aqueous solutions of 1-propanol ( 1P), 2-propanol (2P), glycerol (Gly), and dimethyl sulfoxide ( DMSO), we conclude that there are three composition regions in each of which mixing schemes are qualitatively different. Mixing Schemes II and III, operative in the intermediate and the solute-rich regions, seem similar in all the binary aqueous solutions mentioned above. Mixing Scheme I in the water-rich region is different from solute to solute. 12P shows a behavior similar to that of DMSO, which is somewhat different from typical hydrophobic solute, 1P or 2P. 13P, on the other hand, is less hydrophobic than 12P, and shows a behavior closer to glycerol, which shows hydrophilic behavior.},
	keywords = {2-and 1, 3-propanediols, ALCOHOL, chemical potentials, ENERGIES, ENTHALPIES, ENTROPIES, H2O, interaction functions, MIXING SCHEMES, mixing schemes in aqueous 1, MOLECULAR-ORGANIZATION, NONELECTROLYTES, partial molar, TERT-BUTANOL MIXTURES, VOLUMES, WATER-RICH REGION},
	isbn = {0095-9782},
	url = {<Go to ISI>://000181873700003},
	author = {Parsons, M. T. and Lau, F. W. and Yee, E. G. M. and Koga,Yoshikata}
}
@article {421,
	title = {Mixing schemes in ternary aqueous solutions - Thermodynamic approach},
	journal = {Journal of Thermal Analysis and Calorimetry},
	volume = {69},
	number = {3},
	year = {2002},
	note = {ISI Document Delivery No.: 604BRTimes Cited: 8Cited Reference Count: 282nd International Symposium on the New Frontiers of Thermal Studies of MaterialsNOV 25-27, 2001SUZUKAKEDAI, JAPAN},
	pages = {705-716},
	type = {Proceedings Paper},
	abstract = {The enthalpic interaction functions introduced by us earlier were evaluated in some ternary aqueous solutions. They are determined purely experimentally without resorting to any model system. From them, the pair interaction coefficients based on the virial expansion were evaluated, which will serve for a future theoretical development based on the McMillan-Mayer theory of solution. Secondly, our new methodology of using the mole fraction dependence of the enthalpic interaction function as a probe to elucidate the effect of a third component on the molecular organization is introduced. The conclusions for selected third components in ternary aqueous 1-propanol are reviewed.},
	keywords = {25-DEGREES-C, effect of selected solutes on the molecular organization of H2O, enthalpic interaction functions, ENTROPIES, EXCESS CHEMICAL-POTENTIALS, H2O, MOLECULAR-ORGANIZATION, pair interaction coefficients, PARTIAL MOLAR ENTHALPIES, ternary aqueous solutions, TERT-BUTANOL, TETRAMETHYL UREA, the, VOLUMES, WATER},
	isbn = {1418-2874},
	url = {<Go to ISI>://000178596200002},
	author = {Koga,Yoshikata}
}
@article {4433,
	title = {How dilute is the Henry{\textquoteright}s law region? II},
	journal = {Journal of Physical Chemistry B},
	volume = {102},
	number = {25},
	year = {1998},
	note = {ISI Document Delivery No.: ZV967Times Cited: 13Cited Reference Count: 12},
	month = {Jun},
	pages = {4982-4987},
	type = {Article},
	abstract = {Vapor pressures for n-hexane-c-hexane were measured at extremely low concentrations of n-hexane. The vapor pressure data seemed to indicate within the experimental uncertainty that, in the range of the mole fraction of n-hexane x(nH) < 0.015, the solution obeys Henry{\textquoteright}s law. However, the excess partial molar enthalpy of n-hexane and c-hexane measured by a sensitive microcalorimeter showed that the Henry{\textquoteright}s law is not operative above x(nH) or x(cH) approximate to 2 x 10(-4), the lowest accessible for the calorimetry technique available at present. The excess partial molar enthalpies of the following solutes were also determined in aqueous solutions in an extremely dilute region. Within the experimental technique at our disposal, we could not locate a finite range of Henry{\textquoteright}s law. Thus, whether the solute-solute interaction becomes actually absent or whether such absence depends on the nature of the solvent (H2O or organic) cannot be addressed at present. For aqueous solutions, however, the lower limits of the mole fraction of a solute, above which the solutions behave as non-Henry-like, were found by an order of magnitude lower: 1 x 10(-5) for 2-butoxyethanol; 3 x 10(-5) for tert-butyl alcohol; 2 x 10(-5) for glycerol; 3 x 10(-5) for urea.},
	keywords = {H2O, PERCOLATION, TERT-BUTANOL MIXTURES, VAPOR-PRESSURES, WATER},
	isbn = {1089-5647},
	url = {<Go to ISI>://000074360300017},
	author = {Westh, P. and Haynes, C. A. and Koga,Yoshikata}
}
