Potentiometric study of the protonation equilibrium of Tris(Hydroxymethyl) aminomethane in aqueous sodium perchlorate solutions at 25°C: construction of a thermodynamic model

Gil, Renato L.; Corbillón, M. Soledad; Olazabal, María Ángeles; Madariaga, Juan Manuel

doi:10.1016/s0039-9140(96)02134-0

Cited by 16 publications

(8 citation statements)

References 12 publications

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“…The dependence of the dissociation and stability constants on the ionic strength can be described according to previous work − ,− where I and I 1 are the actual and reference ionic strengths, respectively, and according to eq 10 Z * = pm 2 + qn 2 + r − ( pm + qn + r ) 2 , where m and n are the charges on the metal ion and the ligand, respectively. Considering A = 0.5115 and B = 1.489, we can simplify eq 9: where C and D are empirical coefficients and their values were obtained by minimizing the sum of the squares of the errors ( U ) and the Gauss−Newton nonlinear least-squares method with a suitable computer program: where a is a quasi-experimental quantity and b i is a calculated quantity.…”

Section: Complexation Of Molybdenum(vi) With Eddamentioning

confidence: 99%

“…The dependence of the dissociation and stability constants on the ionic strength can be described according to previous work [4][5][6][7][20][21][22][23][24][25][26] where I and I 1 are the actual and reference ionic strengths, respectively, and according to eq 10 Z* ) pm 2 + qn 2 + r -(pm + qn + r) 2 , where m and n are the charges on the metal ion and the ligand, respectively.…”

Section: Complexation Of Molybdenum(vi) With Eddamentioning

confidence: 99%

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Determination of the Stability Constants of the Mo(VI) Complex with Ethylenediaminediacetic Acid at Different Ionic Strengths

2005

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The solution equilibrium of the molybdenum(VI) complex formed by ethylenediaminediacetic acid (EDDA) has been investigated potentiometrically and spectrophotometrically at 25 °C, pH 6.0, and different ionic strengths ranging from (0.1 to 1.0) mol dm-3 of sodium perchlorate. Molybdenum(VI) forms a mononuclear complex with EDDA of type (MoO3L2-). The dependence of dissociation and stability constants on the ionic strength is described by a modified Debye−Huckel equation and by introducing two empirical parameters. Finally, a comparison has been made between the calculated and experimental values of stability constants.

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Section: Complexation Of Molybdenum(vi) With Eddamentioning

confidence: 99%

Section: Complexation Of Molybdenum(vi) With Eddamentioning

confidence: 99%

Determination of the Stability Constants of the Mo(VI) Complex with Ethylenediaminediacetic Acid at Different Ionic Strengths

2005

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“…The SIT approach has the advantage of being quite simple but, in its original version, is not very accurate in fitting γ values at I < 0.5 mol·kg -1 and at I > 3 mol·kg -1 . Another interesting one-parameter equation for the dependence on ionic strength of activity coefficients has been proposed by Bromley and has been widely used by Madariaga and co-workers − for the dependence of protonation and metal complex formation constants on ionic strength.…”

Section: Introductionmentioning

confidence: 99%

SIT Parameters for the Dependence of (Poly)carboxylate Activity Coefficients on Ionic Strength in (C₂H₄)₄NI_aq (0 ≤ I ≤ 1.2 mol·kg^-1) and (CH₃)₄NCl_aq (0 ≤ I ≤ 3.9 mol·kg^-1) in the Temperature Range 278 K ≤ T ≤ 328 K and Correlation with Pitzer Parameters

et al. 2007

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Parameters for the dependence on ionic strength of activity coefficients for several protonated and unprotonated mono-hexacarboxylates in (C 2 H 5 ) 4 NI and (CH 3 ) 4 NCl aqueous solution were calculated from protonation data [31 polycarboxylates, 613 protonation constants at T ) 298 K, 1244 at T * 298 K, in (C 2 H 5 ) 4 NI; 16 polycarboxylates, 433 protonation constants at T ) 298 K, 308 at T * 298 K (T ) 278 K to 328 K), in (CH 3 ) 4 NCl], at different ionic strengths [0 mol‚kg -1 e I e 1.2 mol‚kg -1 , for (C 2 H 5 ) 4 NI and 0 mol‚kg -1 e I e 3.9 mol‚kg -1 , for (CH 3 ) 4 -NCl)] using a modified SIT model. In this model, the interaction coefficients are considered as dependent on ionic strength according to the equation ) ∞ + ( 0 -∞ )/(I + 1). The analysis of protonation data showed that the parameters for the dependence on both ionic strength and temperature are a simple function of the charge of carboxylate species. Mean values of interaction coefficients are given by the relationships ) jz 2 ; j ∞ ) -0.0188 and -0.0063; j 0 ) 0.2420 and 0.1642 for (C 2 H 5 ) 4 NI and (CH 3 ) 4 NCl, respectively. For the activity coefficients of neutral species, a simple relationship as a function of the number n of carboxylic groups was found: log γ N ) k m I (k m ) Setschenow coefficient); k m ) k h m ‚n, k h m ) -0.0198 and 0.0055, for (C 2 H 5 ) 4 NI and (CH 3 ) 4 NCl, respectively. Mean values of interaction coefficients were also reported for some synthetic and natural polyelectrolytes in (C 2 H 5 ) 4 NI ( j ∞ ) -0.007; j 0 ) 0.199). Furthermore, calculations were made to find the parameters of Pitzer equations. Also in this case, we found a simple relationship between (0) and (1) parameters and species charges. A comparison is given between the SIT and Pitzer models. An almost perfect correlation was found between the SIT and Pitzer coefficients.

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“…Considerable studies have been performed on the ionic strength dependence of the formation constants of some weak complexes of alkali and alkaline earth metals with some organic and inorganic ligands, − and little work has been carried for more stable complexes of α-amino acids with transition-metal ions, − but according to literature, no work has been reported on the ionic strength dependence of formation constants, protonation, and complexation of tungsten(VI) with NTA.…”

Section: Introductionmentioning

confidence: 99%

Dependence on Ionic Strength of Formation Constants, Protonation, and Complexation of Nitrilotriacetic Acid with Tungsten(VI) in Sodium Perchlorate Aqueous Solution

2004

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By use of potentiometric and spectrophotometric techniques, the complexation of tungsten(VI) with nitrilotriacetic acid (NTA) has been carried out in aqueous solution for pH = 7.5 at 25 °C and different ionic strengths ranging from (0.1 to 1.0) mol dm-3 (NaClO4). The composition of the complex was determined by the continuous variations method. It was shown that tungsten(VI) forms a mononuclear complex with NTA of the type (WO3L3-) at pH = 7.5. The dependence of the protonation of the aforementioned ligand and the stability constant of the complex on ionic strength is described by a Debye−Huckel-type equation. Finally the results have been compared with the previously reported data.

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Potentiometric study of the protonation equilibrium of Tris(Hydroxymethyl) aminomethane in aqueous sodium perchlorate solutions at 25°C: construction of a thermodynamic model

Cited by 16 publications

References 12 publications

Determination of the Stability Constants of the Mo(VI) Complex with Ethylenediaminediacetic Acid at Different Ionic Strengths

Determination of the Stability Constants of the Mo(VI) Complex with Ethylenediaminediacetic Acid at Different Ionic Strengths

SIT Parameters for the Dependence of (Poly)carboxylate Activity Coefficients on Ionic Strength in (C₂H₄)₄NI_aq (0 ≤ I ≤ 1.2 mol·kg^-1) and (CH₃)₄NCl_aq (0 ≤ I ≤ 3.9 mol·kg^-1) in the Temperature Range 278 K ≤ T ≤ 328 K and Correlation with Pitzer Parameters

Dependence on Ionic Strength of Formation Constants, Protonation, and Complexation of Nitrilotriacetic Acid with Tungsten(VI) in Sodium Perchlorate Aqueous Solution

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Potentiometric study of the protonation equilibrium of Tris(Hydroxymethyl) aminomethane in aqueous sodium perchlorate solutions at 25°C: construction of a thermodynamic model

Cited by 16 publications

References 12 publications

Determination of the Stability Constants of the Mo(VI) Complex with Ethylenediaminediacetic Acid at Different Ionic Strengths

Determination of the Stability Constants of the Mo(VI) Complex with Ethylenediaminediacetic Acid at Different Ionic Strengths

SIT Parameters for the Dependence of (Poly)carboxylate Activity Coefficients on Ionic Strength in (C2H4)4NIaq (0 ≤ I ≤ 1.2 mol·kg-1) and (CH3)4NClaq (0 ≤ I ≤ 3.9 mol·kg-1) in the Temperature Range 278 K ≤ T ≤ 328 K and Correlation with Pitzer Parameters

Dependence on Ionic Strength of Formation Constants, Protonation, and Complexation of Nitrilotriacetic Acid with Tungsten(VI) in Sodium Perchlorate Aqueous Solution

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SIT Parameters for the Dependence of (Poly)carboxylate Activity Coefficients on Ionic Strength in (C₂H₄)₄NI_aq (0 ≤ I ≤ 1.2 mol·kg^-1) and (CH₃)₄NCl_aq (0 ≤ I ≤ 3.9 mol·kg^-1) in the Temperature Range 278 K ≤ T ≤ 328 K and Correlation with Pitzer Parameters