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.

The kinetics and the mechanism of oxidative decarboxylation of benzilic acid by acidic permanganate (stopped-flow technique) — An autocatalytic study

2004 ◽  
Vol 82 (9) ◽  
pp. 1372-1380 ◽  
Author(s):  
Sairabanu A Farokhi ◽  
Sharanappa T Nandibewoor
Keyword(s):  
Activation Parameters ◽  
Oxidative Decarboxylation ◽  
Two Stage ◽  
First Order ◽  
First Order Kinetics ◽  
Stage Process ◽  
Benzilic Acid ◽  
Reaction Constants ◽  
Kinetics Of ◽  
Good Agreement

The kinetics of the oxidation of benzilic acid by potassium permanganate in an acidic medium were studied spectrophotometrically. The reaction followed a two-stage process, wherein both stages of the reaction followed first-order kinetics with respect to permanganate ion and benzilic acid. The rate of the reaction increased with an increase in acid concentration. Autocatalysis was observed by one of the products, i.e., manganese(II). A composite mechanism involving autocatalysis has been proposed. The activation parameters of the reaction were calculated and discussed and the reaction constants involved in the mechanisms were calculated. There is a good agreement between the observed and calculated rate constants under different experimental conditions.Key words: oxidation, autocatalysis, benzilic acid, two-stage kinetics.

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 Thermodynamic and kinetic studies on saccharide binding to soya-bean agglutinin

1986 ◽  
Vol 234 (3) ◽  
pp. 515-522 ◽  
Author(s):  
M J Swamy ◽  
M V Krishna Sastry ◽  
M I Khan ◽  
A Surolia
Keyword(s):  
Thermodynamic Parameters ◽  
Specific Binding ◽  
Activation Parameters ◽  
Kinetic Studies ◽  
Blue Shift ◽  
Single Step ◽  
Soya Bean ◽  
Saccharide Binding ◽  
Delta G ◽  
Kinetics Of

The fluorescence of N-dansylgalactosamine [N-(5-dimethylaminonaphthalene-1-sulphonyl)galactosamine] was enhanced 11-fold with a 25 nm blue-shift in the emission maximum upon binding to soya-bean agglutinin (SBA). This change was used to determine the association constants and thermodynamic parameters for this interaction. The association constant of 1.51 × 10(6) M-1 at 20 degrees C indicated a very strong binding, which is mainly due to a relatively small entropy value, as revealed by the thermodynamic parameters: delta G = −34.7 kJ × mol-1, delta H = −37.9 kJ × mol-1 and delta S = −10.9 J × mol-1 × K-1. The specific binding of this sugar to SBA shows that the lectin can accommodate a large hydrophobic substituent on the C-2 of galactose. Binding of non-fluorescent ligands, studied by monitoring the fluorescence changes when they are added to a mixture of SBA and N-dansylgalactosamine, indicates that a hydrophobic substituent at the anomeric position increases the affinity of the interaction. The C-6 hydroxy group also stabilizes the binding considerably. Kinetics of binding of N-dansylgalactosamine to SBA studied by stopped-flow spectrofluorimetry are consistent with a single-step mechanism and yielded k+1 = 2.4 × 10(5) M-1 × s-1 and k-1 = 0.2 s-1 at 20 degrees C. The activation parameters indicate an enthalpicly controlled association process.

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.

Effect of Modifying the Anion of an Ionic Liquid on the Outcome of an SN2 Process

2015 ◽  
Vol 68 (1) ◽  
pp. 31 ◽  
Author(s):  
Sinead T. Keaveney ◽  
Dominic V. Francis ◽  
Winnie Cao ◽  
Ronald S. Haines ◽  
Jason B. Harper
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Rate Constant ◽  
Kinetic Data ◽  
Activation Parameters ◽  
Temperature Dependent ◽  
Substitution Process

The effect of a series of ionic liquids containing different anions (bis(trifluoromethanesulfonyl)imide, dicyanimide, hexafluorophosphate, tetrafluoroborate, and bromide) on the rate constant of a bimolecular substitution process was investigated. A general ionic liquid effect was noted, with increases in the rate constant observed in all ionic liquids used when compared with that in acetonitrile. Temperature-dependent kinetic data allowed calculation of activation parameters in each of the reaction mixtures considered; these parameters showed that the microscopic origins of the rate enhancements observed were not the same for all of the ionic liquids used, demonstrating the importance of the nature of the anion.

The oxidation of hydrogen peroxide by tris(polypyridine) complexes of osmium(III), iron(III), ruthenium(III), and nickel(III) in aqueous media

1986 ◽  
Vol 64 (9) ◽  
pp. 1936-1942 ◽  
Author(s):  
Donal H. Macartney
Keyword(s):  
Hydrogen Peroxide ◽  
Exchange Rate ◽  
Rate Constant ◽  
Aqueous Media ◽  
Activation Parameters ◽  
Exchange Rate Constant ◽  
Oxidation Of Hydrogen ◽  
Polypyridine Complexes ◽  
Ph Range ◽  
Kinetics Of

The stoichiometry and kinetics of the oxidation of hydrogen peroxide by tris(2,2′-bipyridine) and tris(4,4′-dimethyl-2,2′-bipyridine) complexes of osmium(III), iron(III), ruthenium(III), and nickel (III) were studied in acidic and neutral aqueous media at 25 °C and I = 0.50 M (LiCF3SO3). The reaction 2M(bpy)33+ + H2O2 → 2M(bpy)32+ + O2 + 2H+ is observed with quantitative yields of dioxygen gas. The observed rate constants displayed an inverse acid dependence over the pH range 6.0–8.5; kobsd = k1 + k2K1/[H+], attributed to the oxidations of H2O2(k1) and HO2− (k2). An application of the Marcus theory relationship to the cross-reaction data gave a self-exchange rate constant of 10−2–10−1 M−1 s−1 for the HO2−/HO2 couple. The electron exchange rate constant is evaluated in terms of the inner-sphere and solvent reorganizational barriers and is compared to values reported for other small molecule couples. Rate and activation parameters for the reduction of the nickel(III) complexes by the hydroxide ion have been determined and are compared with the corresponding values for other metal tris(poly pyridine) complexes.

ChemInform Abstract: Single-Step Methods for Calculating Activation Parameters from Raw Kinetic Data

ChemInform ◽  
1988 ◽  
Vol 19 (24) ◽  
Author(s):  
N. J. BUNCE ◽  
C. L. FORBER ◽  
C. MCINNES ◽  
J. M. HUTSON
Keyword(s):  
Kinetic Data ◽  
Activation Parameters ◽  
Single Step

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

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.

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