Thermodynamic characteristics of stepwise dissociation of glycyl-glycyl-glycine in aqueous solutions

The heats of interaction between glycyl-glycyl-glycine and solutions of nitric acid and potassium hydroxide are determined by calorimetry at 298.15 K and ionic strengths of 0.25, 0.50, and 0.75 in the presence of KNO₃. The standard thermodynamic characteristics (Δ_r H°, Δ_r G°, and Δ_r S°) of acid–base interaction in aqueous solutions of the peptide are calculated. The effect of background electrolyte concentration on the enthalpy of dissociation of glycyl-glycyl-glycine is discussed.     

Thermodynamics of reactions of complex formation for Ce<Superscript>3+</Superscript> and Er<Superscript>3+</Superscript> ions with glycine in an aqueous solution

Enthalpies of complex formation for glycine (HL^±) with Ce³⁺ and Er³⁺ ions at 298.15 K and the value of the ionic strength of 0.5 (KNO₃) are determined by calorimetric means using two independent procedures. Thermodynamic characteristics of the reactions of formation for complexes of glycine with Ce³⁺ and Er³⁺ ions at various [metal]: [ligand] molar ratios are calculated.     

Physical Chemistry of the Interaction of Cellulose with Lignin during Wood Surface Treatment with a Phosphate Flame Retardant

Russian Journal of General Chemistry - A phosphate flame-retardant hardener (PFH) produced on the basis of industrial orthophosphoric acid and acetic anhydride was proposed for reducing the...     

The thermodynamic parameters of the step dissociation of L-phenylalanyl in aqueous solution

The heats of interaction of L-phenylalanine with solutions of nitric acid and potassium and lithium hydroxides were determined calorimetrically at 288.15, 298.15, and 308.15 K and solution ionic strengths of 0.5, 0.75, and 1.0 in the presence of LiNO₃ and KNO₃. The standard thermodynamic characteristics (Δ_r H°, Δ_r G°, Δ_r S°, and ΔC _p ^° of acid-base interactions in aqueous solutions of L-phenylalanine were calculated. The influence of the concentration of background electrolytes and temperature on the heats of dissociation of L-phenylalanine was considered. A comparative analysis of the standard thermodynamic characteristics of step dissociation of L-phenylalanine and alanine was performed in terms of the modern concepts of the structure and physicochemical properties of these compounds and their solutions.     

Standard enthalpies of formation of α-aminobutyric acid and products of its dissociation in an aqueous solution

Heats of solution of crystalline α-aminobutyric acid in water and in aqueous solutions of potassium hydroxide at 298.15 K are measured by means of direct calorimetry. Standard enthalpies of formation of the amino acid and products of its dissociation in an aqueous solution are calculated.     

A thermochemical study of acid-base interactions in aqueous solutions of citric acid

The heat effects of interaction of a solution of citric acid with HNO₃ and KOH were measured calorimetrically at 298.15 K and ionic strengths of 0.5, 1.0, and 1.5 (KNO₃). The heat effects of acid dissociation were calculated using the universal HEAT program. The standard thermodynamic characteristics of step dissociation of citric acid were determined.     

The Heats of Mixing of Aqueous Solutions of Dipeptides with Solutions of Nitric Acid and Potassium Hydroxide over the Temperature Range 288.15–308.15 K

The heats of interaction of D,L-α-alanyl-D,L-valine, β-alanyl-β-alanine, and α-alanyl-β-alanine with solutions of nitric acid and potassium hydroxide were determined calorimetrically at 288.15, 298.15, and 308.15 K and solution ion strengths of 0.5, 1.0, and 1.5 in the presence of KNO₃ and LiNO₃. The heat effects of step dissociation of the dipeptides were calculated using the RRSU universal program. The standard thermodynamic characteristics (Δ_r H ^o, Δ_r G ^o, Δ_r S ^o, and ΔC _p ^o) of proton interaction with the ligands specified were determined. The data obtained were analyzed in terms of Herny concepts. The thermodynamic characteristics of ionization correlated with the structural features of the dipeptides.     

Thermodynamics of the Dissolution of Nitrilotrimethylphosphonic Acid in Water

Russian Journal of Physical Chemistry A - The enthalpies of dissolution of crystalline nitrilotrimethylphosphonic acid С3Н12NO9Р3 (NTPA) in water at 298.15 K are determined...     

Enthalpies of Dissolution of Crystalline Naproxen Sodium in Water and Potassium Hydroxide Aqueous Solutions at 298 K

The enthalpies of dissolution of crystalline naproxen sodium in water and aqueous solutions of KOH at 298.15 K are measured by direct calorimetric means in a wide range of concentrations. The acid–base properties of naproxen sodium at ionic strength I ~ 0 and I = 0.1 (KNO₃) and a temperature of 298.15 K are studied by spectrophotometric means. The concentration and thermodynamic dissociation constants are determined. The standard enthalpies of the formation of naproxen sodium and the products of its dissociation in aqueous solution are calculated.