Aluminum(III)-Isocitrate Solution Chemistry. A Potentiometric Study

1995 ◽  
Vol 48 (5) ◽  
pp. 1039
Author(s):  
KJ Powell ◽  
RM Town
Keyword(s):  
Potentiometric Titration ◽  
Thermodynamic Stability ◽  
Protonation Constants ◽  
Solution Chemistry ◽  
Potentiometric Study ◽  
Equilibrium Reactions

The equilibrium reactions of isocitrate with protons and Al3+ have been studied by potentiometric titration in aqueous 0.10 M KCl at 25°C. The protonation constants, corrected for K+-isocitrate complexing , were logβ0,1,1 = 5.838, logβ0,2,1 = 10.126 and logβ0,3,1 = 13.219. The stabilities and stoichiometries of the complexes, AlpHqLr, were defined by the constants logβ1,1,1 = 9.55(05), logβ1,0,1 = 6.90(02), logβ1,-1,1 = 3.06(04) and logβ2,-3,2 = 4.08(04) or logβ3,-4,3 = 10.36(06). Compared with the Al3+-citrate system, complexes are of lower thermodynamic stability, but equilibrate more rapidly.

Aluminium(III) and Iron(III) 1,2-Diphenolato Complexes: a Potentiometric Study

1985 ◽  
Vol 38 (5) ◽  
pp. 659 ◽  
Author(s):  
JA Kennedy ◽  
HKJ Powell
Keyword(s):  
Aqueous Solution ◽  
Potentiometric Titration ◽  
Protocatechuic Acid ◽  
Acid System ◽  
Experimental Conditions ◽  
Potentiometric Study ◽  
Hydroxo Complexes ◽  
Equilibrium Reactions ◽  
Ternary Metal ◽  
Metal Ligand

The equilibrium reactions between aluminium(III) and the phenols catechol (LH2), protocatechuic acid (LH3) and catechin (LH4), and between iron(III) and protocatechuic acid have been studied by potentiometric titration in aqueous solution, I 0.10M ( KCl ), 25°C. Stability constants are reported for the mononuclear diphenolato complexes AlLHn-2, Al(LHn-2)2and Al(LHn-2)3, and the hydroxo complexes Al(OH)LHn-2 and Al(OH)(LHn-2)2, n = 2 ( catechol ) or 4 ( catechin ). For protocatechuic acid, the carboxylate -coordinated species lLH22+ and the species AlLH + (carboxyl- protonated ) are also postulated. Analogous species were characterized for the iron(III)- protocatechuic acid system. Stoichiometric end-points were obtained only if an excess of ligand was used (L/M > 4). Monomeric and polymeric aluminium- hydroxo species and ternary metal- ligand - hydroxo species were found to be unimportant under the experimental conditions employed.

Aluminum-Tannin Equilibria: A Potentiometric Study

1987 ◽  
Vol 40 (12) ◽  
pp. 2015 ◽  
Author(s):  
H Kipton ◽  
J Powell ◽  
AW Rate
Keyword(s):  
Potentiometric Titration ◽  
Stability Constants ◽  
Potentiometric Study ◽  
Chelate Effect ◽  
Aluminium Ion ◽  
Equilibrium Reactions

The equilibrium reactions between aluminium(III) and an epicatechin polymer or tannin (T) have been studied by potentiometric titration at 25�C, I = 0.001 M. The tannin, which has on average ten 1,2-dihydroxybenzene units per molecule, encapsulates the aluminium ion to form a bis(l,2-diphenolato) complex at pH 5-7. Stability constants are reported for Al(TH-2) (logK11-2, -3.95 � 0.05), Al(TH-3) (logK11-3, -4.5 � 0.1) and Al(TH-4) (logKl1-4, -5.7 � 0.2). A small chelate effect arising from coordination of remote pairs of 1,2-diphenolato groups was observed.

Aluminum(III)-Malonate Equilibria: a Potentiometric Study

1993 ◽  
Vol 46 (5) ◽  
pp. 721 ◽  
Author(s):  
HKJ Powell ◽  
RM Town
Keyword(s):  
Aqueous Solution ◽  
Potentiometric Titration ◽  
Malonic Acid ◽  
Ion Pairing ◽  
Protonation Constants ◽  
Potentiometric Study ◽  
Binary Complexes ◽  
Ph Range ◽  
A Minor

The aluminium(III)-malonic acid (H2L) equilibria have been studied by potentiometric titration in aqueous solution at 25°C (I = 0.10 M KCl ). Data were consistent with the formation of simple binary complexes AlL + (log K1 = 6.711), AlL2- (log K2 = 4.815) and AlL33- (logβ3 = 14.104) in the pH range 2.2-5.5. There was also evidence for a minor species AlL2(OH)2- at pH > 5.8 for solutions with [Al3+]:[LH2] < 3.0 (log KD= -6.68). The protonation constants determined for malonic acid were log K1 = 5.43 and log K2 = 2.60 (corrected for K+ ion pairing).

1:1 and 2:1 Urea−Succinic Acid Cocrystals: Structural Diversity, Solution Chemistry, and Thermodynamic Stability

2010 ◽  
Vol 10 (11) ◽  
pp. 4847-4855 ◽  
Author(s):  
Amjad Alhalaweh ◽  
Sumod George ◽  
Dan Boström ◽  
Sitaram P. Velaga
Keyword(s):  
Succinic Acid ◽  
Thermodynamic Stability ◽  
Structural Diversity ◽  
Solution Chemistry

scholarly journals Comparison of the physical and thermodynamic stability of amorphous azelnidipine and its coamorphous phase with piperazine

RSC Advances ◽  
2018 ◽  
Vol 8 (57) ◽  
pp. 32756-32764 ◽  
Author(s):  
Shuang Du ◽  
Wen Sheng Li ◽  
Ya Rong Wu ◽  
Yan Fu ◽  
Caiqin Yang ◽  
...  
Keyword(s):  
Amorphous Phase ◽  
Thermodynamic Stability ◽  
Solution Chemistry ◽  
Chemistry Method ◽  
Hcl Medium

The thermodynamic stabilities of an amorphous phase and a coamorphous phase of azelnidipine in 0.01 M HCl medium were investigated using a solution chemistry method.

Derivative Analysis of Potentiometric Titration Data To Obtain Protonation Constants

1996 ◽  
Vol 68 (22) ◽  
pp. 3973-3978 ◽  
Author(s):  
Jian-Feng Chen ◽  
Yuan-Xian Xia ◽  
Gregory R. Choppin
Keyword(s):  
Potentiometric Titration ◽  
Protonation Constants ◽  
Derivative Analysis ◽  
Titration Data

Using a Software Application to Evaluation Thermodynamic Stability on the Example of Iron

2019 ◽  
Vol 24 (3) ◽  
pp. 309-312
Author(s):  
Aleksandr S. Gulyaev ◽  
◽  
Vladimir B. Koltsov ◽  
Elena A. Sevryukova ◽  
◽  
...  
Keyword(s):  
Thermodynamic Stability ◽  
Software Application

Solution chemistry effects on the solvation shell of metal ions

2020 ◽  
Author(s):  
Xiangwen Wang ◽  
Dimitrios Toroz ◽  
Seonmyeong Kim ◽  
Simon Clegg ◽  
Gun-Sik Park ◽  
...  
Keyword(s):  
Metal Ions ◽  
Pure Water ◽  
Solvation Shell ◽  
Solution Chemistry ◽  
Chemical Characteristics ◽  
Velocity Autocorrelation Function ◽  
Ionic Solvation ◽  
General Terms ◽  
Alkaline Earth Metal Ions ◽  
Wide Range

<div> <p>As natural aqueous solutions are far from being pure water, being rich in ions, the properties of solvated ions are of relevance for a wide range of systems, including biological and geochemical environments. We conducted ab initio and classical MD simulations of the alkaline earth metal ions Mg<sup>2+</sup> and Ca<sup>2+</sup> and of the alkali metal ions Li<sup>+</sup>, Na<sup>+</sup>, K<sup>+</sup> and Cs<sup>+</sup> in pure water and electrolyte solutions containing the counterions Cl<sup>–</sup> and SO<sub>4</sub><sup>2–</sup>. Through a detailed analysis of these simulations, this study reports on the effect of solution chemistry (composition and concentration of the solution) to the ion–water structural properties and interaction strength, and to the dynamics, hydrogen bond network, and low-frequency dynamics of the ionic solvation shell. Except for the ion–water radial distribution function, which is weakly dependent on the counter-ions and concentrations, we found that all other properties can be significantly influenced by the chemical characteristics of the solution. Calculation of the velocity autocorrelation function of magnesium ions, for example, shows that chlorine ions located in the second coordination shell of Mg<sup>2+</sup> weaken the Mg(H<sub>2</sub>O)<sub>6</sub><sup>2+</sup> hydration ‘cage’ of the cation. The result reported in this study suggest that ionic solvation shell can be significantly influenced by the interactions between other ions present in solution ions, especially those of opposite charge. In more general terms, the chemical characteristics of the solution, including the balance between ion-solvent and ion-ion interactions, could result in significant differences in behavior and function of the ionic solvation shell.</p> </div>

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