Electrochemical and spectroscopic studies of cation radicals. 4. Stopped-flow determination of triarylaminium radical coupling rate constants

1979 ◽  
Vol 83 (6) ◽  
pp. 713-716 ◽  
Author(s):  
Robert F. Nelson ◽  
Robert H. Philp
Keyword(s):  
Rate Constants ◽  
Spectroscopic Studies ◽  
Stopped Flow ◽  
Cation Radicals ◽  
Radical Coupling ◽  
Coupling Rate

scholarly journals Determination of Rate Constants for the Activation Step in Atom Transfer Radical Polymerization Using the Stopped-Flow Technique

2004 ◽  
Vol 37 (8) ◽  
pp. 2679-2682 ◽  
Author(s):  
Tomislav Pintauer ◽  
Wade Braunecker ◽  
Edmond Collange ◽  
Rinaldo Poli ◽  
Krzysztof Matyjaszewski
Keyword(s):  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Rate Constants ◽  
Stopped Flow ◽  
Atom Transfer

scholarly journals Determination of rapid chlorination rate constants by a stopped-flow spectrophotometric competition kinetics method

2014 ◽  
Vol 55 ◽  
pp. 126-132 ◽  
Author(s):  
Dean Song ◽  
Huijuan Liu ◽  
Zhimin Qiang ◽  
Jiuhui Qu
Keyword(s):  
Rate Constants ◽  
Stopped Flow ◽  
Chlorination Rate

The kinetics of partial processes in the oxidation of ascorbic acid catalyzed by vanadyl tetrasulphophthalocyanine

1982 ◽  
Vol 47 (3) ◽  
pp. 744-754 ◽  
Author(s):  
Dana M. Wagnerová ◽  
Jaroslav Votruba ◽  
Jürgen Blanck ◽  
Josef Vepřek-Šiška
Keyword(s):  
Experimental Data ◽  
Ascorbic Acid ◽  
Reaction Mechanism ◽  
Rate Constants ◽  
Stopped Flow ◽  
Adaptive Identification ◽  
Flow Method ◽  
Acid Catalyzed ◽  
Kinetics Of

The rapid partial reactions of the oxidation of ascorbic acid by dioxygen with vanadyl tetrasulphophthalocyanine as a catalyst were studied by the stopped-flow method. The experimental data were treated on a computer and compared with the kinetic implications resulting from the proposed mechanism. Application of the adaptive identification method led to quantitative solution of the mechanism, i.e. determination of the values of all the isolated rate constants of the reaction mechanism.

scholarly journals Determination of the kinetics underlying the pKa shift for the 2-aminoanthracenium cation binding with cucurbit[7]uril

2015 ◽  
Vol 185 ◽  
pp. 381-398 ◽  
Author(s):  
Suma S. Thomas ◽  
Cornelia Bohne
Keyword(s):  
Rate Constants ◽  
Cation Binding ◽  
Stopped Flow ◽  
Ph Values ◽  
Pka Shift ◽  
Changes Over Time ◽  
Initial Binding ◽  
Flow Experiments ◽  
Over Time

The binding dynamics of the 2-aminoanthracenium cation (AH+) and 2-aminoanthracene (A) with cucurbit[7]uril (CB[7]) was studied using stopped-flow experiments. The kinetics was followed by measuring the fluorescence changes over time for AH+ and A, which emit at different wavelengths. The studies at various pH values showed different mechanisms for the formation of the AH+@CB[7] complex, with this complex formed either by the binding of AH+ or by the initial binding of A followed by protonation. In the latter case, it was possible to determine the protonation ((1.5 ± 0.4) × 109 M−1 s−1) and deprotonation (89 ± 7 s−1) rate constants for complexed A/AH+, which showed that the pKa shift of +3.1 for A/AH+ in the complex is mainly due to a lower deprotonation rate constant.

Determination of rate constants of redox reactions of second order from current-less potential-time curves by a simplified graphical-numerical method

1983 ◽  
Vol 48 (5) ◽  
pp. 1358-1367 ◽  
Author(s):  
Antonín Tockstein ◽  
František Skopal
Keyword(s):  
Numerical Method ◽  
Explicit Form ◽  
Rate Constant ◽  
Optimization Algorithm ◽  
Rate Constants ◽  
Redox Reactions ◽  
Second Order ◽  
Wide Region ◽  
Recurrent Formula

A method for constructing curves is proposed that are linear in a wide region and from whose slopes it is possible to determine the rate constant, if a parameter, θ, is calculated numerically from a rapidly converging recurrent formula or from its explicit form. The values of rate constants and parameter θ thus simply found are compared with those found by an optimization algorithm on a computer; the deviations do not exceed ±10%.

Determination of the Accurate Values of the Rate Constant and Thermodynamic Parameters for the Rotation About the C(sp2)-C(aryl) Bond; Adamantan-1-yl 3-Bromo-2,4,6-trimethylphenyl Ketone

1998 ◽  
Vol 63 (7) ◽  
pp. 955-966
Author(s):  
Eva Přibylová ◽  
Miroslav Holík
Keyword(s):  
Thermodynamic Parameters ◽  
Shape Analysis ◽  
Rate Constants ◽  
Line Shape ◽  
Microsoft Excel ◽  
Hindered Rotation ◽  
H Nmr ◽  
Line Shape Analysis ◽  
Coalescence Temperature

Four programs for the 1H NMR line shape analysis: two commercial - Winkubo (Bruker) and DNMR5 (QCPE 165) and two written in our laboratory - Newton (in Microsoft Excel) and Simtex (in Matlab) have been tested in order to get highly accurate rate constants of the hindered rotation about a single bond. For this purpose four testing criteria were used, two of them were also developed by us. As supplementary determinations the rate constants obtained for the coalescence temperature and for the thermal racemization of chromatographically separated enantiomers were used which fitted well the temperature dependence of the rate constants determined by the line shape analysis. As a test compound adamantan-1-yl 3-bromo-2,4,6-trimethylphenyl ketone was prepared and studied. It was shown that supermodified simplex method used in our algorithm (Simtex), though time consuming, gives the most accurate values of the rate constants and consequently the calculated thermodynamic parameters Ea, ∆H≠, and ∆S≠ lay in relatively narrow confidence intervals.

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