Cyclization of O-benzoylbenzamidoxime derivatives in water-alcohol media

1985 ◽  
Vol 50 (12) ◽  
pp. 2722-2729 ◽  
Author(s):  
František Grambal ◽  
Jan Lasovský
Keyword(s):  
Reaction Mechanism ◽  
Electron Acceptor ◽  
Activation Parameters ◽  
Isotopic Effect ◽  
Hammett Equation ◽  
Probability Level ◽  
Kinetic Isotopic Effect ◽  
Cyclization Rate ◽  
Two Parameter ◽  
Water Alcohol

O-Benzoylated benzamidoximes give 1,2,4-oxadiazoles (yields above 90%) in water-alcoholic media of pH = 2.45 to 6.20. The cyclization rate has been studied with 28 derivatives containing different substituents. The reaction is accelerated by electron-donor substituents at 4-position of benzamidoxime and by electron-acceptor substituents at 4'-position of benzoyl. The dependence of the rate constants vs σ values of the substituents fulfils the two-parameter Hammett equation at a 99% probability level. The activation parameters have been determined, and effects of polarity of medium, kinetic isotopic effect, and the reaction mechanism are discussed.

Reaction of 1,3-diphenyltriazene with phenyl isocyanate. Solvent effect, activation parameters and kinetic isotopic effect

1981 ◽  
Vol 46 (6) ◽  
pp. 1376-1382
Author(s):  
Erhard Lejdar ◽  
Oldřich Pytela ◽  
Miroslav Večeřa ◽  
Pavel Vetešník
Keyword(s):  
Hydrogen Atom ◽  
Solvent Effect ◽  
Temperature Dependence ◽  
Activation Parameters ◽  
Phenyl Isocyanate ◽  
Isotopic Effect ◽  
Imino Group ◽  
Reaction Velocity ◽  
Kinetic Isotopic Effect ◽  
Previous Communication

Effect of 14 solvents has been studied on the reaction of phenyl isocyanate with 1,3-diphenyltriazene. For ten of these solvents temperature dependence of the reaction velocity has been determined and the respective activation parameters calculated. Hydrogen atom of the triazene imino group has been replaced by deuterium, and the deuterium kinetic isotopic effect has been studied in seven solvents. The results confirm the mechanism suggested in a previous communication.

ChemInform Abstract: SCHMIDT REACTION MECHANISM. XVII. KINETIC ISOTOPIC EFFECT OF THE REACTION OF BENZALDEHYDE WITH HYDRAZOIC ACID

1976 ◽  
Vol 7 (37) ◽  
pp. no-no
Author(s):  
V. A. OSTROVSKII ◽  
G. I. KOLDOBSKII ◽  
N. P. SHIROKOVA ◽  
B. V. GIDASPOV ◽  
G. M. FROLOVA
Keyword(s):  
Reaction Mechanism ◽  
Isotopic Effect ◽  
Hydrazoic Acid ◽  
Schmidt Reaction ◽  
Kinetic Isotopic Effect

Untersuchung der alkalischen Hydrolyse des Benzoesäurebenzylesters in Wasser-Äthanol 1 : 1 / Study of the Basic Hydrolysis of Benzyl Benzoate in Water-Ethyl Alcohol 1:1

1974 ◽  
Vol 29 (11) ◽  
pp. 1697-1698 ◽  
Author(s):  
F. Mansilla ◽  
P. Martinez ◽  
J. Sancho
Keyword(s):  
Experimental Data ◽  
Reaction Mechanism ◽  
Order Rate Constant ◽  
Benzyl Benzoate ◽  
Conductometric Method ◽  
Alcohol Medium ◽  
Basic Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Water Alcohol

By using a conductometric method, the kinetics of the basic hydrolysis of benzyl benzoate in water-alcohol medium has been investigated. The second order rate constant follows the equation K = A exp {-E/RT} with A = 1.35·1010 l mol-1 min-1 and E = 14.5 kcal mol-1. A reaction mechanism is postulated, which is consistent with the experimental data.

Kinetic Isotopic Effect Studies of Iron–Nitrogen–Carbon Electrocatalysts for Oxygen Reduction Reaction

2019 ◽  
Vol 123 (18) ◽  
pp. 11476-11483 ◽  
Author(s):  
Yechuan Chen ◽  
Tristan Asset ◽  
Rose Lee ◽  
Kateryna Artyushkova ◽  
Plamen Atanassov
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reduction Reaction ◽  
Isotopic Effect ◽  
Kinetic Isotopic Effect

A mathematical modelling of acid catalyzed decomposition of 3-methyl-1,3-diphenyltriazene

1987 ◽  
Vol 52 (10) ◽  
pp. 2492-2499 ◽  
Author(s):  
Oldřich Pytela ◽  
Petr Svoboda ◽  
Miroslav Večeřa
Keyword(s):  
Reaction Mechanism ◽  
Linear Regression ◽  
Organic Solvent ◽  
Mathematical Modelling ◽  
Aqueous Ethanol ◽  
Activation Parameters ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Acid Catalyzed ◽  
Rate Limiting

The effect of acids on the decomposition of 3-methyl-1,3-diphenyltriazene has been studied in aqueous ethanol (40% (v/v) ethanol). The dependences found between the rate constant and acid concentration have been analyzed by means of non-linear regression using models including the specific and general catalysis and formation of associates between the substrate and the buffer components. The substrate has been found to form electrostatic associates with the conjugated base of acid. The complex formed is decomposed with the assistance of the proton or a general acid in the rate-limiting step to form the product. The Bronsted coefficient α = 0.81 has been found. Investigation of the activation parameters supports the earlier conclusions, indicating a dependence between the reaction mechanism and composition of the aqueous organic solvent.

Kinetics and mechanism of aminolysis of (Z)-4-arylidene-2-phenyl-5(4H)oxazolones

1992 ◽  
Vol 70 (10) ◽  
pp. 2515-2519 ◽  
Author(s):  
Sharifa S. Alkaabi ◽  
Ahmad S. Shawali
Keyword(s):  
Rate Constants ◽  
Activation Parameters ◽  
Order Conditions ◽  
Kinetics And Mechanism ◽  
Hammett Equation ◽  
Third Order ◽  
First Order ◽  
Different Temperatures ◽  
Pseudo First Order ◽  
Kinetics Of

The kinetics of the reactions of a series of (Z)-4-arylidene-2-phenyl-5(4H)oxazolones 1 with n-butylamine and piperidine were studied spectrophotometrically in dioxane, ethanol, and cyclohexane under pseudo-first-order conditions and at different temperatures. The relation k1(obs) = k2[amine] + k3[amine]2 was found applicable for all reactions studied in either dioxane or ethanol. However, in cyclohexane the n-butylaminolysis of 1 followed only third-order kinetics k1(obs) = k3[n-BuNH2]2. The kinetics of the reaction of 1 with n-butylamine in the presence of catalytic amounts of triethylamine in dioxane followed the equation: k1(obs)k2 = [n-BuNH2] + k3[n-BuNH2]2[Formula: see text] [Et3N]. The rate constants k2 and k3 correlated well with the Hammett equation and the corresponding activation parameters were determined. The results were interpreted in terms of a mechanism involving solvent- and amine-catalyzed processes.

Fischer–Tropsch Synthesis: Deuterium Kinetic Isotopic Effect for a 2.5 % Ru/NaY Catalyst

2013 ◽  
Vol 57 (6-9) ◽  
pp. 508-517 ◽  
Author(s):  
Jia Yang ◽  
Wilson D. Shafer ◽  
Venkat Ramana Rao Pendyala ◽  
Gary Jacobs ◽  
Wenping Ma ◽  
...  
Keyword(s):  
Isotopic Effect ◽  
Tropsch Synthesis ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Kinetic Isotopic Effect

Thermodynamic Analysis of the Hammett Equation, the Temperature Dependence of ρ, and the Isoequilibrium (Isokinetic) Relationship

1971 ◽  
Vol 49 (17) ◽  
pp. 2803-2807 ◽  
Author(s):  
Loren G. Hepler
Keyword(s):  
Differential Equations ◽  
Temperature Dependence ◽  
Thermodynamic Analysis ◽  
Activation Parameters ◽  
Isokinetic Temperature ◽  
Hammett Equation ◽  
Isokinetic Relationship ◽  
Solvent Interactions ◽  
Independent Constant ◽  
The Relationship

Exact thermodynamic analysis of the Hammett equation has led to four differential equations relating δΔH0, δΔS0, δΔCp0, dρ/dT, and d2ρ/dT2. Similar equations can be obtained in terms of activation parameters ΔH≠, etc. For temperature independent δΔH0 and δΔS0 and therefore δΔCp0 = 0, two of these differential equations lead to ρ = ρ∞ [1–(β1/T)] and the familiar isoequilibrium (isokinetic) equation δΔH0 = β1δΔS0. The "isoequilibrium (isokinetic) temperature" represented here by β1 is a temperature independent constant of integration. For constant non-zero δΔCp0 we similarly obtain more complicated expressions for ρ and the "isoequilibrium (isokinetic) temperature." These findings are considered in relation to a model in which environmental contributions (due to solute–solvent interactions) to δΔH0 and δΔS0 are related by a parameter βc. The relationship between β1, and βc is established, and it is shown that in general β1 ≠ βc.

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