The Effect of Aromatic Amines on the Catalyzed Decarboxylation of 3-Oxo-glutaric Acid

1972 ◽  
Vol 50 (22) ◽  
pp. 3573-3586 ◽  
Author(s):  
K. N. Leong ◽  
M. W. Lister
Keyword(s):  
Ionic Strength ◽  
Stability Constants ◽  
Rate Constants ◽  
Aromatic Amines ◽  
Copper Complexes ◽  
Glutaric Acid ◽  
Equilibrium Constants ◽  
Nickel Compound ◽  
Ph Measurements ◽  
Cobalt Nickel

Equilibrium constants have been measured for the formation of MA species, where M is divalent manganese, cobalt, nickel, or zinc, and A2− is the 3-oxo-glutarate ion. Equilibrium constants have also been measured for the reactions [Formula: see text], where B is 2,2′-bipyridyl or 1,10-phenanthroline. These constants were obtained by pH measurements at 25 °C and an ionic strength of 0.60. The results are compared with those for similar systems, especially as regards the tendency to form ternary mixed complexes of the type MAB.The rates of decarboxylation of the various MA and MAB species have been measured. The resulting rate constants follow the Irving–Williams order for stability constants, except that in both MAB species the cobalt compound decomposed slightly faster than the nickel compound. The aromatic base, which had been found earlier to have very little effect in copper complexes, increased the rate constants appreciably with other metals, especially with manganese and zinc. Usually 1,10-phenanthroline has a larger effect than 2,2′-bipyridyl. Some possible explanations of the results are considered.

The trans effect in cobalt(III) complexes. Kinetics and mechanism of substitution of cobalt(III) sulphito complexes

1978 ◽  
Vol 31 (3) ◽  
pp. 561 ◽  
Author(s):  
JK Yandell ◽  
LA Tomlins
Keyword(s):  
Ionic Strength ◽  
Water Molecule ◽  
Rate Constants ◽  
Equilibrium Constants ◽  
Ion Concentration ◽  
Nitrite Ion ◽  
Hydrogen Ion Concentration ◽  
Thiocyanate Ion ◽  
Order Rate ◽  
Incoming Ligand

Equilibrium constants K and rate constants kf have been measured, at 25°C and ionic strength of 1.0, for the substitution of the labile water molecule in trans-[aquabis(ethylenediamine)sulphito-cobalt(III)] ion by thiosulphate ion (K = 1.8×102 mol-1 1., kf = 1.27×103 mol-1 1. s-1), thiocyanate ion (2.5×103, 2.75×102), nitrite ion (1.0×103, 2.06×102), azide ion (2.9×102, 2.4×102) ferricyanide ion (-, 1.72×103), hydrogen azide (< 1.2,1.4×10), ammonia (3.0, 6.7) and imidazole (2.6×102, 5.2). ��� The correlation of these rate constants with charge on the incoming ligand, as well as a decrease in the apparent second-order rate constants observed at high concentrations of the anionic ligands, requires a rapid outer-sphere pre-equilibrium step followed by a rate- determining dissociative interchange of the incoming ligand with the bound water molecule. The activation energy of the thiocyanate substitution was found to be 48 kJ mol-1. Aquation of cis- [azidobis(ethylenediamine)-sulphitocobalt(III)] ion, in the range of hydrogen ion concentration between 10-2 and 0.2 M, was found to give the trans-aquasulphito complex with a first-order rate constant consistent with the equation ��������������������������� k = 4.9×10-4[H+]+1.0×10-5 s-1 at 25°C and ionic strength 1.0.

ION PAIR EFFECTS IN THE REACTION BETWEEN POTASSIUM FERROCYANIDE AND POTASSIUM PERSULFATE

1966 ◽  
Vol 44 (4) ◽  
pp. 437-445 ◽  
Author(s):  
R. W. Chlebek ◽  
M. W. Lister
Keyword(s):  
Ionic Strength ◽  
Rate Constants ◽  
Equilibrium Constants ◽  
Ion Pairs ◽  
Ion Pair ◽  
Glass Electrode ◽  
Potassium Ferrocyanide ◽  
Potassium Persulfate ◽  
Ion Concentration ◽  
True Rate

The rate of the reaction between potassium ferrocyanide and potassium persulfate has been measured over a range of conditions. The rate is dependent on the potassium ion concentration, and it is shown that this is explained if it is assumed that KFe(CN)63− and KS2O8− are the reacting species. The equilibrium constants governing the formation of these ion pairs were measured with a cation-sensitive glass electrode. Similar constants for the products KFeCCN6)2− and KSO4−, and also for KNO3, were measured. From these equilibrium constants, the true rate constants of the reaction can be obtained, and it is shown that these vary with ionic strength in the manner predicted by Brönsted's equation.

The retroaldol reaction of chalcone

1983 ◽  
Vol 61 (11) ◽  
pp. 2621-2626 ◽  
Author(s):  
J. Peter Guthrie ◽  
John Cossar ◽  
Patricia A. Cullimore ◽  
Nayyer Monshizadeh Kamkar ◽  
Kathleen F. Taylor
Keyword(s):  
Ionic Strength ◽  
Sodium Hydroxide ◽  
Rate Constants ◽  
Equilibrium Constants ◽  
Aqueous Sodium Hydroxide ◽  
Adduct Formation ◽  
Aqueous Sodium ◽  
Catalyzed Reactions

All four rate constants required to describe the hydration and aldolization/dealdolization reactions of chalcone (1,3-diphenyl-2-propen-1-one) have been determined in aqueous sodium hydroxide solutions. Kinetics were studied starting with chalcone, with its hydrate, 1,3-diphenyl-3-hydroxy-1-propanone, and with benzaldehyde in the presence of excess acetophenone. The rate constants for hydroxide catalyzed reactions, defined in terms of eq. [1] are: k12 = 10.5 ± 0.5 × 10−4 M−1 s−1; k21 = 0.026 ± 0.002 M−1 s−1; k23 = 0.194 ± 0.017 M−1 s−1; and k32 = 0.84 ± 0.12 M−2 s−1 (all at ionic strength 0.1). The corresponding equilibrium constants for aldol adduct formation and dehydration are 4.3 M−1 and 25.

scholarly journals The Effect of Aromatic Tertiary Amines on the Copper(II) Catalyzed Decarboxylation of 3-Oxo-Glutaric Acid

1972 ◽  
Vol 50 (10) ◽  
pp. 1461-1467
Author(s):  
K. N. Leong ◽  
M. W. Lister
Keyword(s):  
Copper Complexes ◽  
Glutaric Acid ◽  
Catalytic Effect ◽  
Copper Ions ◽  
Equilibrium Constants ◽  
Copper Ion ◽  
Tertiary Amines ◽  
Selective Electrode ◽  
Equilibrium Concentrations ◽  
Kinetics Of

The kinetics of the copper(II) catalyzed decarboxylation of 3-oxo-glutaric acid have been investigated in unbuffered solutions at 25 °C and 0.60 M ionic strength, both in the presence of aromatic tertiary amines, and with hydrated copper ions alone. The amines used were 2,2′-bipyridyl and 1,10-phenanthroline. Equilibrium constants for the formation of the various copper complexes were determined with a copper ion selective electrode, particularly for the species CuAB, where A is the 3-oxo-glutarate ion, and B is an aromatic amine. The kinetic behavior was then interpreted as arising from the simultaneous decarboxylation of all the species present containing a 3-oxo-glutarate ligand. The resulting rate constants indicated that some kinetic effect was transmitted through the copper from the base to the 3-oxo-glutarate, but the effect was relatively small, and the bulk of the catalytic effect caused by the base arose from changes in equilibrium concentrations.

scholarly journals Spectrophotometric Evaluation of Stability Constants of Copper, Cobalt, Nickel and Zinc with 2-Thiobarbituric Acid in Aqueous Solution

2009 ◽  
Vol 6 (s1) ◽  
pp. S47-S52
Author(s):  
F. Ahmadi ◽  
A. H. M. Sarrafi ◽  
M. M. Ghashghaee
Keyword(s):  
Aqueous Solution ◽  
Data Analysis ◽  
Ionic Strength ◽  
Stability Constants ◽  
Thiobarbituric Acid ◽  
Analysis Program ◽  
Data Analysis Program ◽  
Equilibrium Study ◽  
Cobalt Nickel

Stoichiometry and equilibrium study of ion-ligand conducted in aqueous solution by spectrophotometry. Stability constants of the complexes are determined at 25 °C, ionic strength was adjusted to 0.2 (% w/v) with NaCl. The pH was adjusted to 6. 2-Thiobarbituric acid-ion complexesʼ stability was calculated in aqueous solution using DATAN (Data Analysis program). The results of this method denote formation specie ML2. The log K for ions Cu+2,Co+2, Ni+2and Zn+2were 4.89, 4.69, 4.47 and 4.82, respectively.

Catalytic decomposition of acetonedicarboxylic acid

1968 ◽  
Vol 46 (6) ◽  
pp. 823-832 ◽  
Author(s):  
D. W. Larson ◽  
M. W. Lister
Keyword(s):  
Infrared Spectrum ◽  
Copper Complex ◽  
Rate Constants ◽  
Equilibrium Constants ◽  
Catalytic Decomposition ◽  
Quantitative Correlation ◽  
Cobalt Nickel ◽  
Nickel Copper ◽  
The Stability ◽  
Formation Of Complexes

The decomposition of acetonedicarboxylic acid at various pH and in the presence of cobalt, nickel, copper, and zinc perchlorates as catalysts has been investigated. In addition the equilibrium constants for the formation of complexes between the metal ions and the acetonedicarboxylate ion have been measured.The copper complex appears to differ from the others in being more acidic, and also in its infrared spectrum. The kinetic results have been interpreted in terms of rate constants for the decomposition of each of the complexes, and a qualitative (but not a quantitative) correlation seems to exist between the rate constants and the stability constants of the complexes.

scholarly journals The Stability Constants and Thermodynamic Parameters of Borate - Carbohydrate Complexes by pH Measurements

2012 ◽  
Vol 25 (1) ◽  
pp. 15-20 ◽  
Author(s):  
Farida Akhtar ◽  
Md Anisur Rahman ◽  
DM Shafiqul Islam ◽  
Md Anamul Hoque
Keyword(s):  
Ionic Strength ◽  
Complex Formation ◽  
Thermodynamic Parameters ◽  
Stability Constants ◽  
Chemical Society ◽  
Ph Measurements ◽  
Negative Contribution ◽  
Exothermic Process ◽  
Different Temperatures ◽  
The Stability

The complexation of borate with carbohydrates was studied potentiometrically at  temperatures 298.15-328.15K in aqueous medium at constant ionic strength, I = 0.1M  KCl. The stability constants (?) and thermodynamic parameters of borate-carbohydrate  complexes were determined using the technique proposed by Verchere and Hlaibi.  Carbohydrates such as D-fructose, D-Sorbitol, D-Mannitol, D-Galactose, D-Glucose and  D-Raffinose were used as ligands in this study. The ?1 values for the complexes at  different temperatures were found to follow the order: D-fructose > D-Sorbitol > DMannitol > D-Galactose > D-Glucose > D-Raffinose. The ?G0 values were found to be  negative and the negative values increased according to the above order. The values of  ?H0 and ?S0 were both negative which indicated that the complex formation was an  exothermic process and the spontaneity of its formation is driven by enthalpic  contribution overcoming the negative contribution of ?S0. DOI: http://dx.doi.org/10.3329/jbcs.v25i1.11766 Journal of Bangladesh Chemical Society, Vol. 25(1), 15-20, 2012

Oxidation of (1-hydroxybenzyl)ferrocene and its derivatives substituted in phenyl ring with bis(triphenylsilyl) chromate

1982 ◽  
Vol 47 (12) ◽  
pp. 3375-3380 ◽  
Author(s):  
Jaroslav Holeček ◽  
Karel Handlíř ◽  
Milan Nádvorník ◽  
Milan Vlček
Keyword(s):  
Linear Dependence ◽  
Rate Constants ◽  
Oxidation Rate ◽  
Phenyl Ring ◽  
Equilibrium Constants ◽  
Aprotic Solvents ◽  
Protonation Equilibrium ◽  
Oxidation Of Alcohols ◽  
Hammett Σ Constants ◽  
Sulphuric Acid Medium

Kinetics have been studied of oxidation of (1-hydroxybenzyl)ferrocenes substituted in phenyl ring with bis(triphenylsilyl) chromate in benzene solutions as well as protonation of these alcohols in sulphuric acid medium. Logarithms of the oxidation rate constants (kobs, 20-40 °C) and those of the protonation equilibrium constants (KR+, 25 °C) show linear dependence on the Hammett σ constants, the ρ constant values being -0.86 to -0.40 and -2.50, respectively. These negative values suggest that the both processes are influenced by the same effects and confirm the mechanism proposed earlier for oxidation of alcohols with ferrocenyl substituent by action of bis(triphenylsilyl) chromate in aprotic solvents.

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.

Kinetics of hydrolysis of peroxodisulphate ions in acidic medium to peroxomonosulphuric acid

1981 ◽  
Vol 46 (5) ◽  
pp. 1229-1236 ◽  
Author(s):  
Jan Balej ◽  
Milada Thumová
Keyword(s):  
Ionic Strength ◽  
Rate Constants ◽  
Acidic Medium ◽  
Measured Data ◽  
Molar Ratios ◽  
Starting Solution ◽  
Kinetics Of Hydrolysis ◽  
Rate Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of

The rate of hydrolysis of S2O82- ions in acidic medium to peroxomonosulphuric acid was measured at 20 and 30 °C. The composition of the starting solution corresponded to the anolyte flowing out from an electrolyser for production of this acid or its ammonium salt at various degrees of conversion and starting molar ratios of sulphuric acid to ammonium sulphate. The measured data served to calculate the rate constants at both temperatures on the basis of the earlier proposed mechanism of the hydrolysis, and their dependence on the ionic strength was studied.

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