The heat capacities and critical behaviors of binary ionic solutions

Dependence of ET(30) of solvent parameters on relative permittivity (ε) and refractive index (n) of solvent has been found for forty solvents in the form ET(30)=29.87 + 72.03 (ε - 1/(2ε + 1)-29.16(ε - 1) (n 2 - 1)/(2ε + 1) (2n2 + 1), the correlation coefficient being 0.958. Relation has been discussed between ET(30) and π solvent parameters and significance of the term (ε - 1). (n2 - 1)/(2ε + 1) (2n2 + 1) has been tested for evaluation of solvent effects in electronic spectra.>

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Human Orosomucoid: Dissociation of Tyrosines in the Systems Water-Low Aliphatic Alcohol

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19971533 ◽

1997 ◽

Vol 62 (10) ◽

pp. 1533-1543

Author(s):

Vladimír Karpenko ◽

Jana Horálková ◽

Milan Kodíček

Keyword(s):

Human Serum ◽

Systems Analysis ◽

Titration Curve ◽

Relative Permittivity ◽

Structural Changes ◽

Aliphatic Alcohol ◽

Mixed Media ◽

Spectrophotometric Titration ◽

Electrostatic Effects

The influence of methanol, ethanol, propan-1-ol, and propan-2-ol on the dissociation of tyrosines of human serum orosomucoid (acid α1-glycoprotein) was studied. The content of alcohols was chosen so that their solutions had the same value of the relative permittivity. Then, the contribution of electrostatic effects was equal in all cases and the observed differences between aqueous and alcoholic solutions reflected other, nonelectrostatic effects in the studied systems. Analysis of the spectrophotometric titration curve revealed three kinds of tyrosine groups (n1, n2, n3), but only the values pK1 and pK2 could be calculated. The observed differences of pK values in aqueous and mixed media are discussed and compared with the structural changes of the orosomucoid molecule.

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Heat capacities of liquid 2,3,6-trimethylpyridine, 2,4,6-trimethylpyridine and 3-methoxypropionitrile within the range of temperatures of 300 to 328 K

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19912786 ◽

1991 ◽

Vol 56 (12) ◽

pp. 2786-2790 ◽

Cited By ~ 2

Author(s):

Václav Svoboda ◽

Milan Zábranský

Keyword(s):

Temperature Interval ◽

Atmospheric Pressure ◽

Liquid State ◽

Adiabatic Calorimeter ◽

Heat Capacities

Molar heat capacities of 2,3,6-trimethylpyridine, 2,4,6-trimethylpyridine and 3-methoxypropionitrile in the liquid state were measured at the constant atmospheric pressure in the temperature interval of 300.60 to 328.35 K. The static type of adiabatic calorimeter was used for the measurements.

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Heat capacities and enthalpies of fusion and transformation for solvates of some salts with dimethyl sulfoxide and dimethylformamide

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19883072 ◽

1988 ◽

Vol 53 (12) ◽

pp. 3072-3079

Author(s):

Mojmír Skokánek ◽

Ivo Sláma

Keyword(s):

Heat Capacity ◽

Phase Transformation ◽

Phase Transformations ◽

Dimethyl Sulfoxide ◽

Liquidus Temperature ◽

Molar Heat Capacity ◽

Solid Phase ◽

Zinc Nitrate ◽

Heat Capacities ◽

Liquid Phases

Molar heat capacities and molar enthalpies of fusion of the solvates Zn(NO3)2 . 2·24 DMSO, Zn(NO3)2 . 8·11 DMSO, Zn(NO3)2 . 6 DMSO, NaNO3 . 2·85 DMSO, and AgNO3 . DMF, where DMSO is dimethyl sulfoxide and DMF is dimethylformamide, have been determined over the temperature range 240 to 400 K. Endothermic peaks found for the zinc nitrate solvates below the liquidus temperature have been ascribed to solid phase transformations. The molar enthalpies of the solid phase transformations are close to 5 kJ mol-1 for all zinc nitrate solvates investigated. The dependence of the molar heat capacity on the temperature outside the phase transformation region can be described by a linear equation for both the solid and liquid phases.

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