Schiff base equilibria. V. Beryllium complexes of N-ethylsalicylideneimine

1966 ◽  
Vol 19 (11) ◽  
pp. 2101 ◽  
Author(s):  
RW Green ◽  
RJ Sleet
Keyword(s):  
Schiff Base ◽  
Distribution Coefficient ◽  
Stability Constants ◽  
Formation Constant ◽  
Mixed Complex ◽  
High Ph ◽  
The Stability ◽  
Hydrolysis Of ◽  
Beryllium Complexes

The formation constant and pK at 25� of the Schiff base N- ethylsalicylideneimine (HL) have been found by spectrophotometry to be 2.75x104 and 11.8 respectively. The distribution coefficient of the base from water into toluene is 160. The stability constants of the beryllium complexes determined by solvent distribution are logβ1 10.4 and log β2 18.3, and the distribution coefficient of BeL2 is 260. At high pH the equilibria are complicated by hydrolysis of the Be2+ ion and by formation of the mixed complex, BeL(OH)-2. The latter is formed according to the reaction BeL(H2O)+2 ↔ BeL(OH)-2+2H+ with logKm2 -18.4.

Schiff base equilibria. II. Beryllium complexes of N-n-butylsalicylideneimine and the hydrolysis of the Be2+ ion

1965 ◽  
Vol 18 (5) ◽  
pp. 651 ◽  
Author(s):  
RW Green ◽  
PW Alexander
Keyword(s):  
Aqueous Solution ◽  
Schiff Base ◽  
Complex Formation ◽  
Distribution Coefficient ◽  
Dilute Aqueous Solution ◽  
The Stability ◽  
Ph Range ◽  
Hydrolysis Of ◽  
Beryllium Complexes ◽  
Equilibria In Aqueous Solution

The Schiff base, N-n-butylsalicylideneimine, extracts more than 99.8% beryllium into toluene from dilute aqueous solution. The distribution of beryllium has been studied in the pH range 5-13 and is discussed in terms of the several complex equilibria in aqueous solution. The stability constants of the complexes formed between beryllium and the Schiff base are log β1 11.1 and log β2 20.4, and the distribution coefficient of the bis complex is 550. Over most of the pH range, hydrolysis of the Be2+ ion competes with complex formation and provides a means of measuring the hydrolysis constants. They are for the reactions: Be(H2O)42+ ↔ 2H+ + Be(H2O)2(OH)2, log*β2 - 13.65; Be(H2O)42+ ↔ 3H+ + Be(H2O)(OH)3-, log*β3 -24.11.

scholarly journals Potentiometric and spectrophotometric studies of the complexation of Schiff-base hydrazones containing the pyrimidine moiety

2003 ◽  
Vol 68 (10) ◽  
pp. 729-749 ◽  
Author(s):  
H.S. Seleem ◽  
B.A. El-Shetary ◽  
S.M.E. Khalil ◽  
M. Shebl
Keyword(s):  
Schiff Base ◽  
Ionic Strength ◽  
Thermodynamic Parameters ◽  
Stability Constants ◽  
Elemental Analysis ◽  
Mass Spectra ◽  
Dissociation Constants ◽  
The Stability ◽  
Pyrimidine Moiety ◽  
Metal Ligand

Three Schiff-base hydrazones (ONN ? donors) were prepared by condensation of 2-amino-4-hydrazino-6-methylpyrimidine with 2-hydroxyacetophenone 2-methoxybenzaldehyde and diacetyl to yield 2-OHAHP, 2-OMeBHPand DHP respectively. The structures of these ligands were elucidated by elemental analysis, UV, IR, 1H-NMR and mass spectra. The metal?ligand stability constants of Mn2+, Fe3+,Co2+,Ni2+,Cu2+, Zn2+,Cd2+,UO22+ and Th4+ chelates were determined potentiometrically in two different media (75%(v/v) dioxane?water and ethanol?water) at 283, 293, 303 and 313 K at an ionic strength of 0.05 M (KNO3). The thermodynamic parameters of the 1:1 and 1:2 complexes were evaluated and are discussed. The dissociation constants of 2-OHAHP, 2-OMeBHP and DHPligands and the stability constants of Co2+, Ni2 and Cu2+ with 2-OHAHP were determined spectrophotometrically in 75 % (v/v) dioxane?water.

The Extraction of Anionic Beryllium Complexes by Tri-iso-octylamine

1962 ◽  
Vol 15 (3) ◽  
pp. 457 ◽  
Author(s):  
HJ de Bruin ◽  
D Kairaitis ◽  
RB Temple
Keyword(s):  
Aqueous Solution ◽  
Stability Constants ◽  
Complexing Agents ◽  
Conditional Stability ◽  
Tertiary Amines ◽  
Ph Titration ◽  
Anionic Complexes ◽  
The Stability ◽  
Conditional Stability Constants ◽  
Beryllium Complexes

The extraction of beryllium from aqueous solution by long-chain tertiary amines has been observed in the presence of ligands giving rise to anionic complexes. The nature of the oxalate complex extracted by solutions of tri-iso-octylamine in chloroform has been studied in detail and the species formed in the organic phase were shown to have the composition Be(C2O4)2.{NH(i-C8H15)3}2. The complexes formed in aqueous solution between beryllium and several anionic complexing agents have been examined by the method of pH-titration. Conditional stability constants have been obtained for the complexes formed with oxalic, malonic, maleic, succinic, phthalic, and salicylic acids. Differences in their extractabilities can be explained semiquantitatively with the help of the stability constants and the acid association constants of the complexing agents.

On the Hydrolysis of Tetravalent Metal Ions

2000 ◽  
Vol 663 ◽  
Author(s):  
C. Ekberg ◽  
P. Brown ◽  
J. Comarmond ◽  
Y. Albinsson
Keyword(s):  
Metal Ions ◽  
Stability Constants ◽  
Safety Assessment ◽  
Experimental Conditions ◽  
Polymeric Species ◽  
The Stability ◽  
Hydrolysis Of

ABSTRACTThe stability constants of the hydroxide complexes of zirconium(IV) and uranium(IV) have been measured at 15, 25 and 35°C [in 1.0 mol dm−3 (Na, H)ClO4] using potentiometry. For zirconium(IV), the results indicate the presence of Zr(OH)3+ and the polymeric species Zr3(OH)48+ and Zr4(OH)88+ whereas the results for uranium(IV) indicate the presence of U(OH)3+ and the polymeric species U4(OH)124+. The hydrolysis of both metal ions was studied at three temperatures allowing the determination of ΔH° and ΔS° of reaction for each species. The results were compared with previous results determined for thorium(IV) under the same experimental conditions to ascertain whether thorium should be used as an analogue for other tetravalent metal ions in safety assessment studies of nuclear repositories.

scholarly journals On soil genesis in temperate humid climate. V. The formation of the "albic" and "spodic" horizon.

1965 ◽  
Vol 13 (3) ◽  
pp. 267-279
Author(s):  
J. Van Schuylenborgh ◽  
M.G.M. Bruggenwert
Keyword(s):  
Stability Constants ◽  
Solubility Product ◽  
Humid Climate ◽  
Soil Genesis ◽  
Parent Materials ◽  
Model Substance ◽  
Fe Complexes ◽  
The Stability ◽  
Insoluble Compounds ◽  
Hydrolysis Of

With the aid of parahydroxybenzoic acid as a model substance, some suggestions are given on the formation of the albic and spodic horizons under well-aerated conditions in very poor and acid parent materials. The acid forms soluble complexes with Fe, while insoluble compounds are formed with Al. The stability constants of the Fe complexes and the solubility product of the Al complex were determined. Hydrolysis of the Fe complexes formed in the A horizon, and formation of an insoluble Al complex are the most important mechanisms in the formation of the B2ir and B2h horizons, respectively. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Synthesis, characterization, and thermodynamics of tertiary phosphine cobalt(III) Schiff-base complexes

2001 ◽  
Vol 79 (9) ◽  
pp. 1360-1365 ◽  
Author(s):  
Mozaffar Asadi ◽  
Ali Hossein Sarvestani
Keyword(s):  
Schiff Base ◽  
Ionic Strength ◽  
Thermodynamic Parameters ◽  
Stability Constants ◽  
Schiff Base Complex ◽  
Axial Ligand ◽  
Adduct Formation ◽  
Schiff Base Complexes ◽  
Tertiary Phosphine ◽  
The Stability

[Co(5-nitroSalen)(PBu3)]ClO4·H2O and [Co(Salpd)(PBu3)]ClO4·H2O were synthesized and characterized. The stability constants and the thermodynamic parameters were measured spectrophotometrically for 1:1 adduct formation of [CoL(PBu3)]ClO4·H2O, (L = Salen, 5-nitroSalen, Salpd), and [Co(Salen)(PMe2Ph)]ClO4·H2O as acceptors with P(OR)3, (R = Me, Et, i-Pr) as donors, in acetonitrile solvent and in constant ionic strength (I = 0.01 M) and at various temperatures. The trend of the reactivity of cobalt(III) Schiff-base complexes with PBu3 axial ligand toward a given donor is as follows: 5-nitroSalen > Salen > Salpd.Also, the following reactivity trend of the donors toward a given cobalt(III) Schiff-base complex is in the operation: P(O-i-Pr)3 > P(OEt)3 > P(OMe)3.Key words: cobalt(III) Schiff-base complexes, thermodynamic parameters, trialkylphosphite, adduct complexes, stability constants.

scholarly journals Studies on Metal Gluconic Acid Complexes

2006 ◽  
Vol 932 ◽  
Author(s):  
Peter Warwick ◽  
Nick Evans ◽  
Sarah Vines
Keyword(s):  
Radioactive Waste ◽  
Stability Constants ◽  
Gluconic Acid ◽  
Detrimental Effect ◽  
Solubility Product ◽  
Salt Formation ◽  
High Ph ◽  
Organic Complexes ◽  
The Stability ◽  
Intermediate Level Radioactive Waste

ABSTRACTThe presence of organic complexants, such as gluconic acid, in an intermediate-level radioactive-waste (ILW) repository may have a detrimental effect on the sorption of radionuclides, by forming organic complexes in solution. In order to assess this, stability constants are required for the complexes formed with radionuclides at high pH. This study reports the stability constants for the reactions of some divalent metals with gluconic acid (Gl). The metals studied were Cd, Co, Fe(II), and U(VI) at pH 13.3; and Co and U(VI) at pH 7. The constants were measured by the Schubert (ion-exchange) or solubility product methods. Stoichiometries of the complexes were also determined. At pH 7 each complex was of the form M1Gl1, with log β values suggestive of salt formation. At high pH, log β values were between 13 and 20. The constants have enabled speciation calculations to be performed showing the effect of gluconic acid on the metal's solubility, with data for Ni included. Solubility is predicted to increase in the presence of Gl from pH 9 to 13.5, suggesting that it may have an impact on radionuclide behaviour. The largest solubility increases are for Cd and Co, the smallest, U(VI).

Extraction of strontium and barium salts by the nitrobenzene solution of dicarbolide in the presence of glymes

1985 ◽  
Vol 50 (3) ◽  
pp. 581-599 ◽  
Author(s):  
Petr Vaňura ◽  
Emanuel Makrlík
Keyword(s):  
Stability Constants ◽  
Organic Phase ◽  
Equilibrium Constants ◽  
Minor Role ◽  
Nitrobenzene Solution ◽  
Ligand Structure ◽  
Stability Constants Of Complexes ◽  
Separation Factors ◽  
The Stability ◽  
A Minor

Extraction of microamounts of Sr2+ and Ba2+ (henceforth M2+) from the aqueous solutions of perchloric acid (0.0125-1.02 mol/l) by means of the nitrobenzene solutions of dicarbolide (0.004-0.05 mol/l of H+{Co(C2B9H11)2}-) was studied in the presence of monoglyme (only Ba2+), diglyme, triglyme, and tetraglyme (CH3O-(CH2-CH2O)nCH3, where n = 1, 2, 3, 4). The distribution of glyme betweeen the aqueous and organic phases, the extraction of the protonized glyme molecule HL+ together with the extraction of M2+ ion and of the glyme complex with the M2+ ion, i.e., ML2+ (where L is the molecule of glyme), were found to be the dominating reactions in the systems under study. In the systems with tri- and tetraglymes the extraction of H+ and M2+ ions solvated with two glyme molecules, i.e., the formation of HL2+ and ML22+ species, can probably play a minor role. The values of the respective equilibrium constants, of the stability constants of complexes formed in the organic phase, and the theoretical separation factors αBa/Sr were determined. The effect of the ligand structure on the values of extraction and stability constants in the organic phase is discussed.

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