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Ichihara, Japan

Iwase A.,Nagoya City University | Ueda A.,Nagoya City University | Ueda A.,Nippon Refine CO. | Kuwae A.,Nagoya City University | And 2 more authors.
Journal of Molecular Structure | Year: 2013

Fourier transform (FT) and resonance Raman spectra of 1-methyl-4-(4- diethylaminophenylazo)-pyridinium iodide (MDP) and its four deuterated and three 15N stable isotopic compounds have been measured in neutral and acidic aqueous solutions, and the molecular structures have been discussed on the basis of detailed vibrational assignments using the isotope shifts. No Raman band due to the azo N@N group is observed in a neutral aqueous solution and also in the solid state of MDP; therefore, this finding suggests that double bond character of the azo group becomes weak and, consequently, the structures of both benzene and pyridinium rings are close to that of a quinoid. The Raman and the 15N NMR spectra indicate that the Nb of the azo group is protonated in an acidic solution of MDP. Comparison of the spectra of the two solutions suggests that the benzene ring has more quinoid character in the acidic than in the neutral solution. The chromophore structures have been revealed in each of the neutral (purple) and the acidic (yellow) solution. © 2013 Elsevier B.V. All rights reserved.

Kato S.,Tokyo Metroplitan University | Freitag J.,Nippon Refine CO. | Gostomski P.,University of Canterbury
Fluid Phase Equilibria | Year: 2013

Infinite dilution partial molar excess entropy-enthalpy compensation for polar solutes in an ionic liquid (IL) is investigated using the literature data of infinite dilution activity coefficient, ln γ1∞. Entropy-enthalpy compensation holds for the polar solutes, such as thiophene and CO2, and non-polar solutes, such as heptane and toluene. For the water+IL binaries, a converged linear relationship between infinite dilution partial molar excess entropy and enthalpy holds. Using the compensation rule, it is shown that, for the efficient removal of thiophene and CO2 from non-polar solutes with IL solvents, ILs having weaker molecular interactions with thiophene and CO2 are advantageous, because the entropy terms control the ln γ1∞ values. © 2012 Elsevier B.V.

Kato S.,Tokyo Metroplitan University | Freitag J.,Nippon Refine CO. | Gostomski P.,University of Canterbury | Noritomi H.,Tokyo Metroplitan University | And 3 more authors.
Solvent Extraction Research and Development | Year: 2012

P, x data for the thiophene + [bmim][BF4],+ [bmim][PF6] binaries are correlated using the NRTL equation. It is shown that infinite dilution activity coefficients, γiinfin; , determined from the VLE data are different from experimental γiinfin; values in the thiophene + [bmim][BF4] binary; high-performance regeneration of ionic liquids requires VLE data at infinite dilution.

Kato S.,Tokyo Metroplitan University | Kato S.,TC Lines Co. | Gostomski P.,University of Canterbury | Oda A.,Nippon Refine CO. | And 3 more authors.
Fluid Phase Equilibria | Year: 2013

Binary liquid-liquid equilibrium (LLE) data are correlated using thermodynamic consistency (TC) lines. Of the 283 binaries investigated, 257 have correlation errors less than 3%, providing an average of 0.52%. The average correlation error of the 283 binaries was 2.2%. The TC lines can satisfactorily predict solubilities from near the lower to the upper critical solution temperatures. Furthermore, the TC lines determined from the low-pressure P, x and T, x data can satisfactorily predict the VLE relationships. © 2013 Elsevier B.V.

Freitag J.,Nippon Refine CO. | Kosuge H.,Nippon Refine CO. | Schmelzer J.P.,FH Dresden | Kato S.,Tokyo Metroplitan University | Kato S.,TC Lines Co.
Journal of Chemical Thermodynamics | Year: 2014

A new static cell vapor phase manual sampling (SCVMS1) method is used for the simple measurement of constant temperature x, y (vapor + liquid) equilibria (VLE). The method was applied to the VLE measurements of the (methanol + water) binary at T/K = (283.2, 298.2, 308.2 and 322.9), asymmetric (acetone + 1-butanol) binary at T/K = (283.2, 295.2, 308.2 and 324.2) and two-liquid phase forming azeotropic (water + 1-butanol) binary at T/K = (283.2 and 298.2). The accuracy of the experimental data was approved by a data consistency test, that is, an empirical plot of the polarity exclusion factor, β, vs. the system pressure, P. The SCVMS data are accurate, because the VLE data converge to the same lnβ vs. lnP straight line determined from conventional distillation-still method and a headspace gas chromatography method. © 2014 Elsevier Ltd. All rights reserved.

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