Ion-selective electrode measurements for the determination of formation constants of alkali and alkaline earth metals with low-molecular-weight ligands

Robertis, Alessandro De; Giacomo, Patrizia Di; Foti, Claudia

doi:10.1016/0003-2670(94)00421-h

Cited by 36 publications

(29 citation statements)

References 17 publications

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“…Then, the value of log D is given by The small part of values estimated by the SIT method; this study, × and [13,14] for C20, [12,15,16] for C21-23, [9,17], and [18][19][20][21] for C20-C24, respectively.…”

Section: Formation Constants For Carboxylate Complexesmentioning

confidence: 99%

Hydrolysis constants and complexation of Th(IV) with carboxylates

Sasaki¹,

Takaoka

Kobayashi

et al. 2008

Radiochimica Acta

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Summary. The hydrolysis constants of Th(IV) were determined using the solvent extraction method in a NaClO 4 solution at I = 0.1 and 25• C. A trace amount of thorium below the solubility limit was used in order to avoid the formation of polynuclear species and colloids in the experiment. The values were compared with the literature data. Considering the effect of competitive hydrolysis reactions under weak acid conditions, the complexation constants of Th(IV) with a series of dicarboxylic acids containing different alkyl chain lengths were determined.

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Section: Formation Constants For Carboxylate Complexesmentioning

confidence: 99%

Hydrolysis constants and complexation of Th(IV) with carboxylates

Sasaki¹,

Takaoka

Kobayashi

et al. 2008

Radiochimica Acta

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“…It was found [5] that on changing from Na + to K + , the values of for NaCit 2-and Këit 2-complexes remain equal within the error limits: = 1.43 and = 1.42 (measurements obtained with an inert supporting electrolyte). As follows form the data in [5] and the results obtained in this work, for M 2 Cit -complex, the value of decreases when going from Na + to K + . Thus, deviation from monotonous dependence vs. r å can be explained by different relative sizes of central ions in solutions as compared to their sizes in crystals that are used for qualitative analysis of this dependence.…”

Section: Resultsmentioning

confidence: 81%

Complexation of citric and tartaric acids with Na and K ions in aqueous solution

Zelenina¹,

Zelenin

2005

Russ J Coord Chem

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When studying systems containing citric and tartaric acids, the authors usually chose Na or K salts as supporting electrolytes. However, processes of complex formation of these cations with citrate or tartrate ions are not taken into consideration, which introduces significant errors in the results obtained. The literature data on the stability constant and heat effects of citric acid or tartaric acid complexes with Na or K ions in aqueous solution are listed in Table 1. The analysis of these data reveals their poor agreement, which requires additional study of stability constants of citrate and tartrate complexes with Na or K ions in aqueous solutions. Tetramethylammonium chloride should be used as a supporting electrolyte, which will make it possible to obtain true values of the stability constants. It is also necessary to determine heat effects of complexation of citric and tartaric acids with Na + and K + ions at several values of ionic strength and temperature.This work was undertaken with the aim to study the formation of citrate and tartrate complexes with Na + and K + ions at 298.15 K and ionic strength of a solution 0.1, 0.2, and 0.3, in a wide range of concentrations and pH values. EXPERIMENTALAnalytical grade citric and tartaric acids were used; reagent grade sodium and potassium chlorides were recrystallized twice from redistillate and dried at 430 K to constant weight. Solutions of chlorides were prepared before experiments by dissolving weighed samples in redistillate. High-purity grade tetraethylammonium chloride (TEACl) used as a supporting electrolyte was recrystallized from a mixture of isopropyl alcohol and acetone (the content of chlorine, which was monitored by potentiometric titration with silver nitrate, was 98.5%). Reagent grade hydroxides of tetraethylammonium ( TEAOH ), sodium, and potassium were also used; the content of carbonates in solution did not exceed 1.5%, which was controlled by acid-base titration with two indicators. Foreign ion impurities contained in TEAOH were removed by passing a solution through ion-exchange resin in OH-form.The stability constants of Na and K complexes with citric and tartaric acids were determined by potentiometric titration. The emf of a cell consisting of a glass and silver-chloride electrodes was measured. The glass electrode potential was measured with a P-363 potentiometer and a 340 pH-meter served as zero instrument. An accuracy of potential measurements was ± 0.1 mV; the temperature in potentiometric cell was maintained with an accuracy of ± 0.1 K. Before each experiment and after recording the titration curve, the device was calibrated with the standard solutions of HCl and TEAOH (0.01 mol/l) at a given ionic strength of a solution. The titration curves were recorded at I = 0.1 and 0.3 mol/l of TEACl and at 298.15 K. In order to prevent penetration of CO 2 from air, inert gas (argon) was passed though a solution in potentiometric cell. The potentiometric titration was conducted by two methods.1. A precise volume (20.03 ml) of citric (tartaric) ...

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“…In order to draw a whole picture of the speciation of naturally occurring ligands in sea water and to evaluate the cumulative complexing capacity of sea water, the interactions between components of ionic medium (SSWE), must be considered. On the basis of results obtained by some investigations on the interactions of seawater macro components (De Robertis et al, 1994aDe Stefano et al, 1994a), it is Table 2.…”

Section: Resultsmentioning

confidence: 99%

Equilibrium studies in natural fluids: interactions of -PO₄³⁻, -P₂O₇⁴⁻and -P₃O₁₀⁵⁻with the major constituents of sea water

Stefano

Foti

Gianguzza

et al. 1998

Chemical Speciation & Bioavailability

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Ion-selective electrode measurements for the determination of formation constants of alkali and alkaline earth metals with low-molecular-weight ligands

Cited by 36 publications

References 17 publications

Hydrolysis constants and complexation of Th(IV) with carboxylates

Hydrolysis constants and complexation of Th(IV) with carboxylates

Complexation of citric and tartaric acids with Na and K ions in aqueous solution

Equilibrium studies in natural fluids: interactions of -PO₄³⁻, -P₂O₇⁴⁻and -P₃O₁₀⁵⁻with the major constituents of sea water

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Ion-selective electrode measurements for the determination of formation constants of alkali and alkaline earth metals with low-molecular-weight ligands

Cited by 36 publications

References 17 publications

Hydrolysis constants and complexation of Th(IV) with carboxylates

Hydrolysis constants and complexation of Th(IV) with carboxylates

Complexation of citric and tartaric acids with Na and K ions in aqueous solution

Equilibrium studies in natural fluids: interactions of -PO43−, -P2O74−and -P3O105−with the major constituents of sea water

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Equilibrium studies in natural fluids: interactions of -PO₄³⁻, -P₂O₇⁴⁻and -P₃O₁₀⁵⁻with the major constituents of sea water