Viscosities of L-leucine/L-glutamine/L-alanine/glycylglycine + 0.512 mol·kg<sup>-1</sup> aqueous K<sub>2</sub>SO<sub>4</sub>/0.512mol·kg<sup>-1</sup> aqueous K...Viscosities of L-leucine/L-glutamine/L-alanine/glycylglycine + 0.512 mol·kg<sup>-1</sup> aqueous K<sub>2</sub>SO<sub>4</sub>/0.512mol·kg<sup>-1</sup> aqueous KNO<sub>3</sub> solutions have been measured as a function of molal concentration of amino acids/peptides at different temperatures (298.15, 303.15, 308.15, 313.15, 318.15 and 323.15) K. Using the viscosity values of the studied systems the viscosity B-coefficients and activation parameters: , , and have been computed. The B-coefficient is a quantity of active solvodynamic measurements of solvated ion and also is overseen through magnitude and form properties of solute, and the basic effects made by means of the solute-solvent functioning. The experimental and computed parameters have been discussed in terms of ion-ion, hydrophilicion and hydrophobicion interactions operative in the systems.展开更多
The solvation of carbon dioxide in sea water plays an important role in the carbon circle and the world climate. The salting-out/salting-in mechanism of CO2 in electrolyte solutions still remains elusive at molecule l...The solvation of carbon dioxide in sea water plays an important role in the carbon circle and the world climate. The salting-out/salting-in mechanism of CO2 in electrolyte solutions still remains elusive at molecule level. The ability of ion salting-out/salting-in CO2 in electrolyte solution follows Hofmeister Series and the change of water mobility induced by salts can be predicted by the viscosity B-coefficients. In this work, the chemical potential of carbon dioxide and the dynamic properties of water in aqueous NaCl, KF and NaClO4 solutions are calculated and analyzed. According to the viscosity B-coefficients, NaClO4 （0.012） should salt out the carbon dioxide relative to in pure water, but the opposite effect is observed for it. Our simulation results suggest that the salting-in effect of NaClO4 is due to the strongly direct anion-CO2 interaction. The inconsistency between＂ Hofmeister Series and the viscosity B-coefficient suggests that it is not always right to indicate whether a salt belongs to salting-in or salting-out just from these properties of the salt solution in the absence of solute.展开更多
Density （ρ） and viscosity （η） measurements were carried out for 4-aminobutyric acid in 0.0041,0.0125 and 0.0207 mol·L-1 aqueous salbutamol sulphate at T=308.15,313.15 and 318.15K.The measured values of dens...Density （ρ） and viscosity （η） measurements were carried out for 4-aminobutyric acid in 0.0041,0.0125 and 0.0207 mol·L-1 aqueous salbutamol sulphate at T=308.15,313.15 and 318.15K.The measured values of density and viscosity were used to estimate some important parameters such as apparent molar volume Vφ,limiting apparent molar volume Vφ0,transfer volume △Vφ0,hydration number Hn,second derivative of infinite dilution of partial molar volume with temperature 2Vφ0/T2,viscosity B-coefficients,variation of B with temperature dB/dT,free energy of activation per mole of solvent △μ10＊ and solute △μ20＊,activation entropy △S20＊ and activation enthalpy △H20＊ of the amino acids.These parameters have been interpreted in terms of solute-solute and solute-solvent interactions and structure making/breaking ability of solutes in the given solution.展开更多
Density（ρ）and viscosity（η）are measured for glycine,DL-α-alanine DL-α-valine,and DL-α-leucine in 0.05,0.10,0.15 and 0.20 mol·L^-1aqueous metformin hydrochloride at 308.15,313.15 and 318.15 K.The measured ...Density（ρ）and viscosity（η）are measured for glycine,DL-α-alanine DL-α-valine,and DL-α-leucine in 0.05,0.10,0.15 and 0.20 mol·L^-1aqueous metformin hydrochloride at 308.15,313.15 and 318.15 K.The measured values are used to estimate some important parameters,such as partial molal volume Vφ,standard partial molal volume Vφ^0,transfer volume ΔVφ^0,hydration number nH,the second derivative of infinite dilution of partial molal volume with respect to temperature,viz., ^2 Vφ^0 /T^2,viscosity B-coefficient,variation of B with temperature,viz., dB/dT,free energy of activation per mole of solvent Δμ1^＊0 and solute Δμ2^0＊ of the amino acids.These parameters are interpreted in terms of solute-solute and solute-solvent interactions and structure making/breaking ability of solutes in the given solution.In addition,Vφ^0,0 ΔVφ^0,viscosity B-coefficient,ΔB and Δμ2 ^0＊ are split into group contributions（NH3^＋ COO ^-）and -CH2 of the amino acids using their linear correlation and their behavior is discussed.展开更多
文摘Viscosities of L-leucine/L-glutamine/L-alanine/glycylglycine + 0.512 mol·kg<sup>-1</sup> aqueous K<sub>2</sub>SO<sub>4</sub>/0.512mol·kg<sup>-1</sup> aqueous KNO<sub>3</sub> solutions have been measured as a function of molal concentration of amino acids/peptides at different temperatures (298.15, 303.15, 308.15, 313.15, 318.15 and 323.15) K. Using the viscosity values of the studied systems the viscosity B-coefficients and activation parameters: , , and have been computed. The B-coefficient is a quantity of active solvodynamic measurements of solvated ion and also is overseen through magnitude and form properties of solute, and the basic effects made by means of the solute-solvent functioning. The experimental and computed parameters have been discussed in terms of ion-ion, hydrophilicion and hydrophobicion interactions operative in the systems.
文摘The solvation of carbon dioxide in sea water plays an important role in the carbon circle and the world climate. The salting-out/salting-in mechanism of CO2 in electrolyte solutions still remains elusive at molecule level. The ability of ion salting-out/salting-in CO2 in electrolyte solution follows Hofmeister Series and the change of water mobility induced by salts can be predicted by the viscosity B-coefficients. In this work, the chemical potential of carbon dioxide and the dynamic properties of water in aqueous NaCl, KF and NaClO4 solutions are calculated and analyzed. According to the viscosity B-coefficients, NaClO4 （0.012） should salt out the carbon dioxide relative to in pure water, but the opposite effect is observed for it. Our simulation results suggest that the salting-in effect of NaClO4 is due to the strongly direct anion-CO2 interaction. The inconsistency between＂ Hofmeister Series and the viscosity B-coefficient suggests that it is not always right to indicate whether a salt belongs to salting-in or salting-out just from these properties of the salt solution in the absence of solute.
文摘Density （ρ） and viscosity （η） measurements were carried out for 4-aminobutyric acid in 0.0041,0.0125 and 0.0207 mol·L-1 aqueous salbutamol sulphate at T=308.15,313.15 and 318.15K.The measured values of density and viscosity were used to estimate some important parameters such as apparent molar volume Vφ,limiting apparent molar volume Vφ0,transfer volume △Vφ0,hydration number Hn,second derivative of infinite dilution of partial molar volume with temperature 2Vφ0/T2,viscosity B-coefficients,variation of B with temperature dB/dT,free energy of activation per mole of solvent △μ10＊ and solute △μ20＊,activation entropy △S20＊ and activation enthalpy △H20＊ of the amino acids.These parameters have been interpreted in terms of solute-solute and solute-solvent interactions and structure making/breaking ability of solutes in the given solution.
文摘Density（ρ）and viscosity（η）are measured for glycine,DL-α-alanine DL-α-valine,and DL-α-leucine in 0.05,0.10,0.15 and 0.20 mol·L^-1aqueous metformin hydrochloride at 308.15,313.15 and 318.15 K.The measured values are used to estimate some important parameters,such as partial molal volume Vφ,standard partial molal volume Vφ^0,transfer volume ΔVφ^0,hydration number nH,the second derivative of infinite dilution of partial molal volume with respect to temperature,viz., ^2 Vφ^0 /T^2,viscosity B-coefficient,variation of B with temperature,viz., dB/dT,free energy of activation per mole of solvent Δμ1^＊0 and solute Δμ2^0＊ of the amino acids.These parameters are interpreted in terms of solute-solute and solute-solvent interactions and structure making/breaking ability of solutes in the given solution.In addition,Vφ^0,0 ΔVφ^0,viscosity B-coefficient,ΔB and Δμ2 ^0＊ are split into group contributions（NH3^＋ COO ^-）and -CH2 of the amino acids using their linear correlation and their behavior is discussed.
