Density, viscosity, and refractive index, for glycine, DL-alanine, L-serine and DL-valine have been determined in aqueous solution of 0.05 mol/kg caffeine as a function of amino acid （AA） concentration at 25, 30, 35...Density, viscosity, and refractive index, for glycine, DL-alanine, L-serine and DL-valine have been determined in aqueous solution of 0.05 mol/kg caffeine as a function of amino acid （AA） concentration at 25, 30, 35, and 40 ℃ The density data have been used to compute apparent molar volume. The partial molar volume （limiting apparent molar volume） was obtained by applying the Masson＇s equation. The viscosity data have been analyzed by means of Jones-Dole equation. The values of Falkenhagen coefficient and Jones-Dole coefficient thus obtained are used to interpret the solute-solute and solute-solvent interactions, respectively. Hydration number was also computed. The transition-state theory was applied to obtain the activation parameters of viscous flow, i.e., free energy of activation per mole of solvent, and solute. The enthalpy and entropy of activation of viscous flow were computed for the system. Refractive index was used to calculate molar refractivity of the mixtures. The results have been interpreted in the light of various interactions occurring between the components of the mixtures under applied experimental conditions.展开更多
The effects of CuCl_(2) and ZnCl_(2) on the viscosity in aqueous ethanol mixtures(10%–50%v/v)were studied in the concentration range 1.0×10^(–2)–8.0×10^(–2) mol·dm^(–3) at different temperatures.It...The effects of CuCl_(2) and ZnCl_(2) on the viscosity in aqueous ethanol mixtures(10%–50%v/v)were studied in the concentration range 1.0×10^(–2)–8.0×10^(–2) mol·dm^(–3) at different temperatures.It was found that the viscosities increased with an increase in the concentration of the salts and percent composition of ethanol content,whereas it decreased with an increase in temperature.Ion-ion and ion-solvent interactions are determined with the help of A-and B-coefficients of Jones-Dole equation.The values of A-and B-coefficients are irregular and increase with a rise in temperature and also with an increase in ethanol contents for both salts.Negative values of B-coefficients show that ion solvent interactions is comparatively small and suggest that CuCl_(2) and ZnCl_(2) behave as structure breakers in aqueous ethanol mixtures.Thermodynamic parameters like the energy of activation(Eη)and change in entropy of activation(ΔS*)were also evaluated which confirm the structure breaker behavior of salts in aqueous ethanol mixtures.展开更多
文摘Density, viscosity, and refractive index, for glycine, DL-alanine, L-serine and DL-valine have been determined in aqueous solution of 0.05 mol/kg caffeine as a function of amino acid （AA） concentration at 25, 30, 35, and 40 ℃ The density data have been used to compute apparent molar volume. The partial molar volume （limiting apparent molar volume） was obtained by applying the Masson＇s equation. The viscosity data have been analyzed by means of Jones-Dole equation. The values of Falkenhagen coefficient and Jones-Dole coefficient thus obtained are used to interpret the solute-solute and solute-solvent interactions, respectively. Hydration number was also computed. The transition-state theory was applied to obtain the activation parameters of viscous flow, i.e., free energy of activation per mole of solvent, and solute. The enthalpy and entropy of activation of viscous flow were computed for the system. Refractive index was used to calculate molar refractivity of the mixtures. The results have been interpreted in the light of various interactions occurring between the components of the mixtures under applied experimental conditions.
文摘The effects of CuCl_(2) and ZnCl_(2) on the viscosity in aqueous ethanol mixtures(10%–50%v/v)were studied in the concentration range 1.0×10^(–2)–8.0×10^(–2) mol·dm^(–3) at different temperatures.It was found that the viscosities increased with an increase in the concentration of the salts and percent composition of ethanol content,whereas it decreased with an increase in temperature.Ion-ion and ion-solvent interactions are determined with the help of A-and B-coefficients of Jones-Dole equation.The values of A-and B-coefficients are irregular and increase with a rise in temperature and also with an increase in ethanol contents for both salts.Negative values of B-coefficients show that ion solvent interactions is comparatively small and suggest that CuCl_(2) and ZnCl_(2) behave as structure breakers in aqueous ethanol mixtures.Thermodynamic parameters like the energy of activation(Eη)and change in entropy of activation(ΔS*)were also evaluated which confirm the structure breaker behavior of salts in aqueous ethanol mixtures.
