Structure–reactivity correlations of substituted 2-phenylthiazolidines

1992 ◽  
Vol 70 (7) ◽  
pp. 2009-2014 ◽  
Author(s):  
R. Umarani ◽  
G. Radhakrishnan
Keyword(s):  
Kinetic Data ◽  
Activation Parameters ◽  
Hammett Equation ◽  
Ethyl Bromoacetate ◽  
Linear Relationships ◽  
Kinetics Of

Systematic investigations of the kinetics of the reactions of ethyl bromoacetate (EBA) and of picryl bromide (PB) with 2-phenylthiazolidines (PT) in 100% ethanol were undertaken at 30, 35, 40, and 45 °C. The most incisive information concerning the Hammett equation comes from the extensive studies on the substituted 2-phenylthiazolidines, establishing linear Hammett plots with negative ρ values. The kinetic data, plotted in a Brønsted fashion against pKa of the corresponding thiazolidinium ions, yield linear relationships. The activation parameters were computed. The linear relationships between ΔH≠ and ΔS≠ signify a consistent mechanism throughout the series.

scholarly journals Kinetics and mechanism of the C-S coupling reactions of aryl Grignard reagents with aryl arenesulfonates

2008 ◽  
Vol 6 (2) ◽  
pp. 237-244 ◽  
Author(s):  
Ender Erdik ◽  
Fatma Eroğlu
Keyword(s):  
Nucleophilic Addition ◽  
Kinetic Data ◽  
Grignard Reagent ◽  
Activation Parameters ◽  
Grignard Reagents ◽  
Coupling Reactions ◽  
Sulfonyl Group ◽  
First Order ◽  
Kinetics Of ◽  
Hammett Relationship

AbstractThe kinetics of the C-S coupling of arylmagnesium bromides with phenyl tosylate has been studied in THF: toluene at 90°C. The reaction is first order in Grignard reagent and first order in phenyl tosylate. Kinetic data, Hammett relationship and activation parameters are consistent with a nucleophilic addition mechanism involving rate determining attack of carbanion to sulfonyl group followed by a fast phenoxide group leaving.

scholarly journals Kinetics of solvolysis in water of four secondary alkyl nitrates

1982 ◽  
Vol 60 (13) ◽  
pp. 1780-1785 ◽  
Author(s):  
Ross Elmore Robertson ◽  
Kalvelil Matthew Koshy ◽  
Adrianne Annessa ◽  
Jan N. Ong ◽  
John Marshall William Scott ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Rate Constant ◽  
Analytical Methods ◽  
Kinetic Data ◽  
Activation Parameters ◽  
Single Step ◽  
Alkyl Nitrates ◽  
Two Stage ◽  
Kinetics Of ◽  
Single Step Reaction

Kinetic data are reported for the solvolysis in water of propane-2-nitrate, butane-2-nitrate, cyclopentyl nitrate, and cyclohexyl nitrate. In each case, the dependence of rate constant on temperature is analysed in terms of two mechanisms for the solvolytic reaction. First it is assumed that the rate constant describes a single step reaction, the analysis leading to estimates of the heat capacity of activation ΔCp≠. Three different analytical methods are discussed in this regard. Second it is assumed that the rate constant describes a two stage mechanism, the first stage being reversible. In this case the explanation of the ΔCp≠ term calculated according to the first mechanism is quite different. We comment on the alternative explanations of trends in activation parameters.

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.

Kinetics and mechanism of the oxidation of 1-propane thiol by 2,6-dichlorophenolindophenol in acidic medium

1982 ◽  
Vol 60 (15) ◽  
pp. 1928-1932 ◽  
Author(s):  
M. Kashyap ◽  
K. K. Mishra ◽  
N. K. Pandey
Keyword(s):  
Kinetic Data ◽  
Acidic Medium ◽  
Reaction System ◽  
Activation Parameters ◽  
Molar Ratio ◽  
Water Medium ◽  
Reaction Products ◽  
Kinetics Of Oxidation ◽  
Acetone Water ◽  
Kinetics Of

The kinetics of oxidation of 1-propanethiol by 2,6-dichlorophenolindophenol have been studied in acetone–water medium and in the presence of phosphate buffer. The principal reactants interact in a molar ratio of 2:1 forming disulphide and dihydroindophenol. The reaction follows second order kinetics in indophenol while the order is unity in thiol. The rate increases linearly on increasing [H+]. The rate of oxidation increases on increasing the ionic strength as well as the dielectric constant of the reaction system. The addition of reaction products has no effect on the rate. Activation parameters have been evaluated and a suitable mechanism consistent with kinetic data is suggested.

Kinetics of redox reaction of lactic acid with bromate ions, and Belousov-Zhabotinskii oscillator with lactic acid

1985 ◽  
Vol 50 (7) ◽  
pp. 1588-1593 ◽  
Author(s):  
Ľubica Adamčíková ◽  
Irena Halinárová
Keyword(s):  
Lactic Acid ◽  
Induction Period ◽  
Redox Reaction ◽  
Kinetic Data ◽  
Activation Parameters ◽  
Oscillation Period ◽  
Probable Mechanism ◽  
Hydrogen Ions ◽  
First Order ◽  
Kinetics Of

The kinetics and mechanism of the redox reaction of bromate ions with lactic acid was studied in the medium of sulphuric acid. The reaction is of first order with respect to both reactants. The dependence of the measured rate constant on the concentration of hydrogen ions was analysed and the activation parameters of the reaction were determined. Based on the experimental kinetic data, the probable mechanism is discussed. Oscillations of bromine and catalyst are observed in the system KBrO3-CH3CHOHCOOH-H2SO4-MnSO4 if the solution is bubbled with nitrogen. The dependence of the induction period and oscillation period on the concentration of the reactants was evaluated.

scholarly journals Kinetics of base hydrolysis of α-amino acid esters catalyzed by palladium(II) piperazine complex

2010 ◽  
Vol 8 (4) ◽  
pp. 797-805 ◽  
Author(s):  
Azza Shoukry ◽  
Mohamed Shoukry ◽  
Mohamed Hafez
Keyword(s):  
Kinetic Data ◽  
Methyl Esters ◽  
Activation Parameters ◽  
Base Hydrolysis ◽  
Amino Acid Esters ◽  
One Step ◽  
Glycine Methyl Ester ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Acid Esters

AbstractThe kinetics of base hydrolysis of glycine, histidine, and methionine methyl esters in the presence of [Pd(pip)(H2O)2]2+ complex, where pip is piperazine, is studied in aqueous solutions, at T = 25°C, and I = 0.1 mol dm−3. The rate of ester hydrolysis for glycine methyl ester is studied at different temperature and dioxane/water solutions of different compositions. The kinetic data are fit under the assumption that the hydrolysis proceeds in one step. The activation parameters for the base hydrolysis of the complexes are evaluated

Kinetics of alkaline hydrolysis and correlation studies of m- and p-substituted piperidinoethyl phenylcarbamates

1989 ◽  
Vol 54 (7) ◽  
pp. 1846-1853 ◽  
Author(s):  
Mária Stankovičová ◽  
Jozef Čižmárik
Keyword(s):  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Activation Parameters ◽  
Hammett Equation ◽  
Correlation Studies ◽  
Lipophilicity Parameter ◽  
Substituent Constants ◽  
Kinetics Of

Kinetics of alkaline hydrolysis have been studied with a series of 15 m- and p-substituted piperidinoethyl phenylcarbamates. The rate constants have been determined at 70, 60, 50, and 40 °C and the activation parameters have been calculated. These values have been correlated with the substituent constants σ, F, R, F, R, π. Validity of the Hammett equation and the Swain-Lupton equation has been confirmed in the series studied and for the p-derivatives, respectively. The lipophilicity parameter π does not correlate with the values found.

scholarly journals Oxidation of Chalcones by Morpholinium Chlorochromate with Oxalic Acid as Catalyst: Kinetic and Mechanistic Study

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
K. Rajalakshmi ◽  
T. Ramachandramoorthy
Keyword(s):  
Acetic Acid ◽  
Ionic Strength ◽  
Kinetic Data ◽  
Reaction Rate ◽  
Activation Parameters ◽  
Mechanistic Study ◽  
Kinetics Of Oxidation ◽  
Unit Order ◽  
Acetic Acid Water ◽  
Kinetics Of

The kinetics of oxidation of chalcones by morpholinium chlorochromate (MCC) has been studied in 55% acetic acid-water (v/v) medium. The reaction showed unit order dependence each with respect to oxidant and catalyst and fractional order with respect to substrate and H+ion. Increased ionic strength has no effect on the reaction rate. In the case of substituted chalcones, the order with respect to substrate varies depending upon the nature of the substituent present in the ring. In general, the electron withdrawing substituents retard the reaction rate while the electron releasing substituents enhance the rate of the reaction. From the kinetic data obtained, the activation parameters have been calculated and a suitable mechanism has been proposed.

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (03) ◽  
pp. 100-103 ◽  
Author(s):  
C. Schümichen ◽  
J. Waiden ◽  
G. Hoffmann
Keyword(s):  
Glomerular Filtration ◽  
Renal Clearance ◽  
Plasma Protein ◽  
Kinetic Data ◽  
Adult Rats ◽  
Compound A ◽  
Extravascular Space ◽  
Tubular Cells ◽  
Glomerular Filtrate ◽  
Kinetics Of

SummaryThe kinetic data of two different 99mTc-Sn-pyrophosphate compounds (compound A and B) were evaluated in non-adult rats. Only compound A concentrated in bone. Both compounds dispersed rapidly in the intravascular as well as the extravascular space. The plasma protein bond of both compounds increased with time after injection and impaired both the renal clearance of both compounds and the bone clearance of compound A. The renal clearance of both compounds was somewhat above that of 5 1Cr-EDTA. It is concluded that compound A and B is mainly excreted by glomerular filtration. About one fourth of the glomerular filtrate of compound B is reabsorbed and accumulated by the tubular cells.

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