@article {2123,
	title = {Chemical Potentials in Aqueous Solutions of Some Ionic Liquids with the 1-Ethyl-3-methylimidazolium Cation},
	journal = {Journal of Physical Chemistry B},
	volume = {112},
	number = {42},
	year = {2008},
	note = {ISI Document Delivery No.: 361AWTimes Cited: 3Cited Reference Count: 33Kato, Hitoshi Nishikawa, Keiko Murai, Hiromi Morita, Takeshi Koga, Yoshikata},
	month = {Oct},
	pages = {13344-13348},
	type = {Article},
	abstract = {We determined the vapor pressures of aqueous solutions of 1-ethyl-3-methylimidazolium ([C(2)mim])-based ionic liquids (IL) with counteranions, tetrafluoroborate (BF4-), trifluoromethanesulfonate (OTF-), and iodide (I-) Because in literature the evidence is accumulating and pointing to the fact that ionic liquid ions do not dissociate in aqueous media for the most of the concentration range, we analyzed the vapor pressure data on the basis of binary mixture, and the excess chemical potentials of each component were calculated. From these, the intermolecular interactions in terms of excess chemical potential and hence the concentration fluctuations were evaluated. Though any further discussion into the mixing schemes of the mixture awaits the excess partial molar enthalpy and hence the excess partial molar entropy data, the net interaction in terms of excess chemical potential indicates that the affinity of each IL is ranked in the descending order [C2mim]l > [C(2)mim]OTF > [C(2)mim]BF4. This is consistent with our earlier findings that [C(2)mim](+) is modestly amphiphilic with almost equal hydrophobicity and hydrophilicity, I- is a hydrophile, and OTF- is amphiphilic, and BF4- is believed to be strongly hydrophobic.},
	keywords = {1-BUTYL-3-METHYLIMIDAZOLIUM, ACETONITRILE, AGGREGATION BEHAVIOR, ENTHALPY-ENTROPY COMPENSATION, MIXING SCHEMES, MOLECULAR-ORGANIZATION, SYSTEMS, TETRAFLUOROBORATE, TETRAFLUOROBORATE PLUS WATER, THERMODYNAMIC APPROACH, VAPOR-PRESSURE MEASUREMENT},
	isbn = {1520-6106},
	url = {<Go to ISI>://000260100900026},
	author = {Kato, H. and Nishikawa, K. and Murai, H. and Morita, T. and Koga,Yoshikata}
}
@article {1440,
	title = {The effects of chloride salts of some cations on the molecular organization of H2O. Towards understanding the Hofmeister series. II},
	journal = {Bulletin of the Chemical Society of Japan},
	volume = {79},
	number = {9},
	year = {2006},
	note = {ISI Document Delivery No.: 097WCTimes Cited: 7Cited Reference Count: 42Koga, Yoshikata Katayanagi, Hideki Davies, James V. Kato, Hitoshi Nishikawa, Keiko Westh, Peter},
	month = {Sep},
	pages = {1347-1354},
	type = {Article},
	abstract = {We use the thermodynamic behaviour of I-propanol (1P) as a probe in ternary 1P-salt-H2O systems to elucidate the effect of a salt on the molecular organization of H2O. For salts, we have chosen CaCl2, NH4Cl, and (CH3)(4)NCl (TMAC). Having fixed the counter anion at Cl-, we compare here mainly the effects of chosen cations on H2O. Together with an earlier study on NaCl, we found that Ca2+, Na+, and NH4+ are hydrated by a number of H2O molecules and leave the bulk H2O away from the hydration shell unperturbed. The hydration numbers were found to be 6.4 +/- 1.6, and 1.2 +/- 0.4, for Ca2+ and NH4+, respectively with the hydration number 5.2 for Na+, the result of a simulation study, chosen as a reference. Thus, a salting out (also referred to as structure making, stabilizing, or kosmotropic) tendency would decrease in the order; Ca2+ > Na+ > NH4+. TMA(+), on the other hand, showed a more hydrophilic characteristics than the probing 1P. Thus, TMA(+) is rather chaotropic (salting in, structure breaking or destabilizing) within this methodology.},
	keywords = {AQUEOUS-SOLUTIONS, EXCESS CHEMICAL-POTENTIALS, HEAT-CAPACITIES, INTERMOLECULAR INTERACTIONS, MIXING SCHEMES, PARTIAL MOLAR ENTHALPIES, TETRAALKYLAMMONIUM HALIDES, TETRAMETHYL UREA, THERMODYNAMIC APPROACH, WATER MIXTURES},
	isbn = {0009-2673},
	url = {<Go to ISI>://000241479100004},
	author = {Koga,Yoshikata and Katayanagi, H. and Davies, J. V. and Kato, H. and Nishikawa, K. and Westh, P.}
}
@article {1201,
	title = {Hydrophobicity vs hydrophilicity: Effects of poly(ethylene glycol) and tert-butyl alcohol on H2O as probed by 1-propanol},
	journal = {Journal of Physical Chemistry B},
	volume = {109},
	number = {41},
	year = {2005},
	note = {ISI Document Delivery No.: 974SQTimes Cited: 8Cited Reference Count: 33},
	month = {Oct},
	pages = {19536-19541},
	type = {Article},
	abstract = {The enthalpic interaction between 1-propanol (IP) molecules, H-1P- 1P(E), was evaluated in 1P-poly(ethleneglycol) (PEG)-H2O and 1P-tert-butyl alcohol (TBA)-H2O ternary mixtures. The model-free and experimentally accessible quantity, H-1P-1p(E), indicates the effect of an additional 1P on the actual enthalpic situation of 1P in the mixture. It was shown earlier that the composition dependence of H-1P-1P(E) reflects the process how 1P modifies H2O. This H-1P-1P(E) pattern changes in the presence of a third component, PEG or TBA. The effects of PEG or TBA on the molecular organization of H2O were elucidated from these induced changes. Together with previous similar studies for the effects of methanol (ME), 2-propanol (2P), ethylene glycol (EG), and glycerol (Gly), we suggest a method and hence a possible scaling for sorting out hydrophobicity vs hydrophilicity of these alcohols by the changes induced to the loci of the maxima in H-1P-1P(E). We show that hydrophilicity scales with the number of oxygen, regardless of whether O is the ether -O- or the hydroxyl -OH. Hydrophobicity also scales with the number of carbon atoms for alcohols without a methyl group. For those with methyl groups, the hydrophobicity seems proportional to the total number of carbon with a different proportionality factor from those without methyl group.},
	keywords = {25-DEGREES-C, ALKANE-MONO-OLS, AQUEOUS-SOLUTIONS, EXCESS CHEMICAL-POTENTIALS, GLYCEROL, HOFMEISTER SERIES, MIXING SCHEMES, MOLECULAR-ORGANIZATION, PARTIAL MOLAR ENTHALPIES, THERMODYNAMIC APPROACH},
	isbn = {1520-6106},
	url = {<Go to ISI>://000232612100072},
	author = {Miki, K. and Westh, P. and Koga,Yoshikata}
}
@article {913,
	title = {Effects of Na2SO4 and NaClO4 on the molecular organization of H2O},
	journal = {Journal of Physical Chemistry A},
	volume = {108},
	number = {10},
	year = {2004},
	note = {ISI Document Delivery No.: 801KFTimes Cited: 11Cited Reference Count: 16},
	month = {Mar},
	pages = {1635-1637},
	type = {Letter},
	abstract = {We study thermodynamic behaviors of 1-propanol (abbreviated as 1P) in ternary 1P-salt-H2O in order to elucidate the effects of salt on the molecular organization of H2O. We determine the excess partial molar enthalpy of 1P, H-1P(E), as a function of the mole fraction of 1P, x(1P), and the salt. We examine the x(1P) dependence of H-1P(E), and changes induced by the presence of salt are used to elucidate the effect of the salt on the molecular organization of H2O. We previously found that an NaCl ion pair binds 7 to 8 molecules of H2O, but has no effect on H2O outside of the hydration shell. Na2SO4 and NaClO4, on the other hand, modify the molecular organization of H2O each in different ways. In particular, ClO4- seems to participate in the hydrogen bond network of H2O and to retard the degree of fluctuation inherent in liquid H2O.},
	keywords = {25-DEGREES-C, AQUEOUS-SOLUTIONS, MIXING SCHEMES, PARTIAL MOLAR ENTHALPIES, THERMODYNAMIC APPROACH, WATER},
	isbn = {1089-5639},
	url = {<Go to ISI>://000220094100001},
	author = {Koga,Yoshikata and Westh, P. and Nishikawa, K.}
}
@article {912,
	title = {Toward understanding the Hofmeister series. 1. Effects of sodium salts of some anions on the molecular organization of H2O},
	journal = {Journal of Physical Chemistry A},
	volume = {108},
	number = {40},
	year = {2004},
	note = {ISI Document Delivery No.: 858TGTimes Cited: 18Cited Reference Count: 28},
	month = {Oct},
	pages = {8533-8541},
	type = {Article},
	abstract = {We studied a detailed thermodynamic behavior of 1-propanol (abbreviated as 1P) in mixed solvents of aqueous Na2SO4, NaOOCCH3, and NaClO4, and NaSCN. We measured the excess partial molar enthalpy of 1P, H-1P(E), in these mixed solvents at various initial salt concentrations. We then evaluated what we call the enthalpic interaction, H-1P-1P(E) = (partial derivativeH(1P)(E)/partial derivativen(1P)), where n(1P) is the amount of 1P. The composition dependence of H-1P-1P(E) changes in a characteristic manner on addition of a specific salt. This induced change in the behavior of H-1P-1P(E) is used to elucidate the effect of the salt on the molecular organization of H2O. Na+ ion seems to hydrate a number less than seven or eight molecules of H2O, leaving the bulk H2O outside the hydration shell unperturbed. SO42- also hydrates a number less than 26 H2O molecules with a concomitant increase in the degree of fluctuation of the bulk H2O. Na2SO4 as a whole hydrates the total of 26 H2O. CH3COO- ion modifies H2O in a similar manner as an alcohol. Cl- ion hydrates a number less than seven or eight H2O molecules leaving the bulk H2O in the same state as in pure H2O. NaCl as a whole hydrates the total of seven or eight molecules of H2O. ClO4- and SCN- participate in hydrogen bonding with the hydrogen bond network of H2O keeping its connectivity intact. However, they reduce the degree of fluctuation inherent in liquid H2O. Thus, each ion has its own unique manner of modifying H2O, except that ClO4- and SCN- modify H2O in almost the same way. Therefore, it seems fair to state that the phenomenological net result manifested as the Hofmeister series is due to multifacetted factors working in the holistic manner, and a single or a small number of parameters is not sufficient to explain its effect.},
	keywords = {1-PROPANOL, 25-DEGREES-C, ALKANE-MONO-OLS, AQUEOUS-SOLUTIONS, fluctuations, MIXING SCHEMES, PARTIAL MOLAR ENTHALPIES, THERMODYNAMIC APPROACH, WATER},
	isbn = {1089-5639},
	url = {<Go to ISI>://000224214100050},
	author = {Koga,Yoshikata and Westh, P. and Davies, J. V. and Miki, K. and Nishikawa, K. and Katayanagi, H.}
}
@article {655,
	title = {Effect of ethylene glycol on the molecular organization of H2O in comparison with methanol and glycerol: A calorimetric study},
	journal = {Journal of Solution Chemistry},
	volume = {32},
	number = {9},
	year = {2003},
	note = {ISI Document Delivery No.: 742ZVTimes Cited: 8Cited Reference Count: 25},
	month = {Sep},
	pages = {803-818},
	type = {Article},
	abstract = {Excess partial molar enthalpies of ethylene glycol, H-EG(E), in binary ethylene glycol-H2O, and those of 1-propanol, H-IP(E), in ternary 1-propanol-ethylene glycol (or methanol)-H2O were determined at 25degreesC. From these data, the solute-solute interaction functions, H-EG-EG(E)=N(partial derivativeH(EG)(E)/partial derivativen(EG)) and H-1P-1P(E)=N(partial derivativeH(1P)(E)/partial derivativen(1P)), were calculated by graphical differentiation without resorting to curve fitting. Using these, together with the partial molar volume data, the effect of ethylene glycol on the molecular organization of H2O was investigated in comparison with methanol and glycerol. We found that there are three concentration regions, in each of which the mixing scheme is qualitatively different from the other regions. Mixing scheme III operative in the solute-rich region is such that the solute molecules are in a similar situation as in the pure state, most likely in clusters of its own kind. Mixing scheme II, in the intermediate region, consists of two kinds of clusters each rich in solute and in H2O, respectively. Thus, the bond percolation nature of the hydrogen bond network of liquid H2O is lost. Mixing scheme I is a progressive modification of liquid H2O by the solute, but the basic characteristics of liquid H2O are still retained. In particular, the bond percolation of the hydrogen bond network is still intact. Similar to glycerol, ethylene glycol participates in the hydrogen bond network of H2O via-OH groups, and reduces the global average of the hydrogen bond probability and the fluctuations inherent in liquid H2O. In contrast to glycerol, there is also a sign of a weak hydrophobic effect caused by ethylene glycol. However, how these hydrophobic and hydrophilic effects of ethylene glycol work together in modifying the molecular organization of H2O in mixing scheme I is yet to be elucidated.},
	keywords = {25-DEGREES-C, ALKANE-MONO-OLS, AQUEOUS-SOLUTIONS, CHEMICAL-POTENTIALS, effect on the, enthalpic interaction, enthalpy, ethylene glycol-H2O, excess partial molar, methanol-, MIXING SCHEMES, molecular organization of H2O, or glycerol-H2O, PARTIAL MOLAR ENTHALPIES, TERT-BUTANOL MIXTURES, THERMODYNAMIC APPROACH, VOLUMES, WATER},
	isbn = {0095-9782},
	url = {<Go to ISI>://000186548700004},
	author = {Koga,Yoshikata}
}
