Katsutoshi Tamura

Speeds of sound, isentropic and isothermal compressibilities, and isochoric heat capacities of {xc-C6H12+(1−x)C6H6}, x{CCl4+(1−x)C6H6}, and x{C7H16+(1−x)C6H6} at 298.15 K

Abstract The speeds of sound and densities of { xc -C 6 H 12 +(1− x )C 6 H 6 }, { x CCl 4 +(1− x )C 6 H 6 }, and { x C 7 H 16 +(1− x )C 6 H 6 } were measured at 298.15 K. The identropic compressibilities of these solutions were estimated from the results, and the isothermal compressibilities and isochoric heat capacities were also calculated. The error propagated in the derivation of each property was estimated. The excess functions of these properties are expressed by the Redlich-Kister equation, on the basis of the excess values proposed by Benson and his colleagues.

Excess molar volumes, isentropic and isothermal compressibilities, and isochoric heat capacities of (acetonitrile + benzene), (benzene + dimethylformamide), and (acetonitrile + dimethylformamide) at the temperature 298.15 K

Densities ρ and speeds of sound u of {xCH3CN + (1 − x)C6H6}, {xC6H6 + (1 − x)HCON(CH3)2}, and {xCH3CN + (1 − x)HCON(CH3)2} were measured at the temperature 298.15 K. Excess molar volumes VEm and excess isentropic compressibilities kES of the mixtures were estimated from the results. Excess isothermal compressibilities kET and excess isochoric molar heat capacities CEV, m of the mixtures were also estimated from the measurements and the previous isobaric molar heat capacities Cp, m. VEm{xCH3CN + (1 − x)C6H6} changes sign from negative to positive with increase of x, VEm{xC6H6 + (1 − x)HCON(CH3)2} and VEm{xCH3CN + (1 − x)HCON(CH3)2} are negative over the whole composition range. kES and kET of the mixtures are in the similar trend to the corresponding VEm. CEV, m{xCH3CN + (1 − x)C6H6} changes sign from positive to negative with increase of x, and CEV, m{xC6H6 + (1 − x)HCON(CH3)2} is negative with a small positive region at x > 0.95. CEV, m{xCH3CN + (1 − x)HCON(CH3)2} is negative over the whole range, though CEp, m is complicatedly dependent on x.

Isotope effects on thermodynamic properties in four binary systems: Water (or heavy water) + dimethylsulfoxide (or N,N-Dimethylformamide) at 25‡C

Excess enthalpy, excess isobaric heat capacity, density, and speed of sound in mixtures of heavy water (D2O) + dimethylsulfoxide (DMSO), and D2O + dimethylformamide (DMF) were measured at 25‡C. The same properties of the mixtures of normal water + DMSO, and H2O + DMF were also measured to estimate isotope effects on the thermodynamic excess functions. Both DMSO and DMF are proton acceptors and thus form hydrogen bonds with water. Large negative excess enthalpies and volumes of mixing and excess isentropic compressibilities show that the hydrogen bonding structures of DMSO and DMF with water are stronger and more compact than those in pure water. The excess heat capacity of DMSO-containing mixtures changes sign from negative to positive with increasing water content. The deviations of the excess properties of D2O systems from those of H2O systems indicate that the hydrogen bonding structure with D2O is stronger and more compact.

Speeds of sound, densities, and isentropic compressibilities of {xc−C6H12+(1−x) C6H5CH3}, {xc−C6H11CH3+(1−x)C6H6}, and {xc−C6H11CH3+(1−x)C6H5CH3}, from 293.15 to 303.15 K

Abstract The speeds of sound u and densities ϱ of { xc -C 6 H 12 +(1− x )C 6 H 5 CH 3 }, { xc -C 6 H 11 CH 3 +(1− x )C 6 H 6 }, and { xc -C 6 H 11 CH 3 +(1− x )C 6 H 5 CH 3 }, were measured at 298.15 K. Those of the first and second mixtures were also measured at 293.15 and 303.15 K. Isentropic compressibilities κ S of the mixtures were estimated from the results. For { xc -C 6 H 11 CH 3 +(1− x )C 6 H 5 CH 3 } the isothermal compressibilities κ T and isochoric heat capacities C V , m were estimated by use of C p , m E s. The excess functions V m E , κ S E , κ T E , C V , m E , and the apparent excess speeds of sound δu , defined as the excess over the linear value with those of mole fraction, were also estimated and discussed in connection with those of { xc -C 6 H 12 +(1− x )C 6 H 6 } reported in a previous paper. (1) The methyl group existing as a lump on a smoothly ellipsoidal molecule obviously affects the excess properties through changes in the molecular packing in mixtures. Changes of the excess properties with temperature are very small.

Excess volumes of water + acetonitrile and water + dimethylsulfoxide at 30°C and the effect of the excess thermal expansivity coefficients on derived thermodynamic properties

AbstractExcess molar volumes

Speeds of sound, isentropic and isothermal compressibilities, and isochoric heat capacities of {xc−C6H12+(1−x)C6H6} from 293.15 to 303.15 K

V_{\text{m}}^{\text{E}}

Thermodynamic Properties of Aqueous Solution of 2-Isopropoxyethanol at 25°C

of water + acetonitrile, and water + dimethylsulfoxide mixtures were measured at 30°C. Excess thermal expansivity coefficients αE were calculated from values of