S. N. Gridchin

The step dissociation constants of ethylenediamine-N,N′-diacetic-N,N′-dipropionic and ethylenediamine-N,N,N′,N′-tetrapropionic acids

The step dissociation constants of ethylenediamine-N,N′-diacetic-N,N′-dipropionic and ethylenediamine-N,N,N′,N′-tetrapropionic acids at 298.15 K and ionic strengths of 0.1, 0.5, and 1.0 (KNO3) were determined potentiometrically. The results were extrapolated to zero ionic strength by the equation with one individual parameter. The thermodynamic constants of dissociation were calculated. The results are compared with the corresponding data on related compounds.

The thermal effects of acid-base interactions in aqueous solutions of D,L-α-alanyl-glycine

The heat effects of protolytic equilibria of D,L-α-alanyl-glycine at 298.15 K and ionic strengths of 0.1, 0.3, 0.5, and 1.0 (KNO3) were determined by direct calorimetry. The standard thermodynamic characteristics of these equilibria were calculated. The results were compared with the data on related compounds.

Enthalpy of solution of VOCl3 in dilute sodium hydroxide solutions and the standard enthalpy of formation of the HVO 4 2− ion

The calorimetric enthalpies of solution of liquid vanadium oxytrichloride in dilute sodium hydroxide solutions were measured at 298.15 K and ionic strengths I = 0.5, 1.0, or 1.5 (NaClO4). The standard enthalpy of formation of the HVO42− ion was calculated from the measured data.

Thermodynamic characteristics of protolytic equilibria of ethylenediamine-N,N′-diacetic-N,N′-dipropionic acid

Heat effects of protonation and neutralization of ethylenediamine-N,N′-diacetic-N,N′-dipropionic acid at 298.15 K and ion force values of 0.1, 0.5, and 1.0 (KNO3) were measured by the direct calorimetric method. Combined use of the results of thermochemical and potentiometric measurements carried out under the identical experimental conditions permitted to evaluate standard thermodynamic characteristics of the equilibria under study. The results obtained were compared with the corresponding data for related compounds considering the specific features of structure of the diamine complexones.

The heats of interaction of L-glutamine and L-glutamic acid with KOH and HNO3 in aqueous solutions

The heat effects of protolytic equilibria of L-glutamine and L-glutamic acid at 298.15 K and ionic strengths of 0.1, 0.3, 0.5, and 1.0 (KNO3) were determined by the direct calorimetric method. Standard thermodynamic characteristics of the equilibria were calculated.

The thermodynamic characteristics of step dissociation of trimethylenediamino-N,N,N′,N′-tetraacetic acid

The heat effects of step dissociation of trimethylenediamino-N,N,N′,N′-tetraacetic acid were determined by direct calorimetry at 298.15 K and I = 0.1, 0.5, and 1.0 (KNO3). The thermochemical and potentiometric measurement data obtained under equal experimental conditions were used jointly to determine the standard thermodynamic characteristics of the equilibria studied. The results obtained are compared with the corresponding data on related compounds.

Thermodynamic characteristics of protolytic equilibria of D,L-alanyl-D,L-leucine in aqueous solution

Previously unknown thermal effects of the stepwise dissociation of D,L-alanyl-D,L-leucine were determined by direct calorimetric measurements. The standard thermodynamic characteristics of the dissociation equilibria were calculated. The results were compared with the published data for related compounds.

Thermodynamic characteristics of protolytic equilibria of trimethylenediamine- N,N,N′,N′ -tetraacetic acid

The thermal effects of the neutralization of betainic protons of trimethylenediamine-N,N,N′,N′-tetraacetic acid (H4L) at 298.15 K and ionic strength of 0.3, 0.5, and 1.0 (KNO3) were directly measured by calorimetry. The standard thermodynamic characteristics of the protolytic equilibria of H4L were calculated from a combination of thermochemical and potentiometric data obtained under identical experimental conditions. The results obtained were compared with the corresponding data for related compounds taking into account the specific structure of diamine complexones.

Effect of background electrolyte concentration on the heat effects in the processes of formation of L-asparagine complexes with Cu2+ ions in aqueous solution

A direct calorimetric method was used to measure the heat effects in the reactions of formation of Cu(II) complexes with L-asparagine in aqueous solutions at 298.15 K and ionic strength 0.5, 1.0, 1.5 (KNO3). The standard thermodynamic characteristics (ΔrH0, ΔrG0, ΔrS0) of the processes of complex formation in the system under study were calculated.

The thermodynamic characteristics of complex formation between Cd2+ and ethylenediamine-N,N′-disuccinic acid in aqueous solution

The enthalpies of complex formation between ethylenediamine-N,N′-disuccinic acid (H4A) and Cd2+ ions were determined calorimetrically at 298.15 K and ionic strengths of 0.5, 1.0, and 1.5 (KNO3). The thermodynamic characteristics of formation of the CdA2− and CdHA− complexes at fixed and zero ionic strengths were calculated. The values obtained were interpreted.