Influence of TTAB/14-S-14 Micelles on the Rate of the Condensation between Ninhydrin and Mercury-Dipeptide Complex in Absence and Presence of Salts and Organic Solvents: A Kinetic Approach

The interaction of mercury(II)–glycyl-L-alanine [Hg(II)–Gly-L-Ala]+ complex with ninhydrin has been studied kinetically both in aqueous as well as micellar media (cationic conventional/gemini surfactants) using UV-vis spectrophotometer at 70 ºC and a particular pH 5.0. The study was carried out as functions of [Hg(II)–Gly-L-Ala]+, [ninhydrin], [surfactant] [salts], and solvents (%v/v). The first-order-rate is observed concerning [Hg(II)–Gly-L-Ala]+, whereas fractional-order-rate dependence for [ninhydrin]. It has been found that 14-s-14 geminis enhance the rate of reaction more effectively than related cationic conventional surfactant tetradecyltrimethylammonium bromide (TTAB). The effect of additives such as salts (inorganic/organic) and organic solvents on the rate was also investigated. The reaction rate was explained in terms of the modified pseudo phase model (considering the association/adsorption of both the reactants on the micellar surface) and changes in micellar morphology occurring at higher [geminis]. The Eyring equation is valid for the reaction over the range of temperatures used. Various thermodynamic parameters and binding constants between reactants with the micelles have been evaluated.

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Kinetics of Reduction of Colloidal MnO2 by Glyphosate in Aqueous and Micellar Media

International Journal of Inorganic Chemistry ◽

10.1155/2011/243519 ◽

2011 ◽

Vol 2011 ◽

pp. 1-6 ◽

Cited By ~ 3

Author(s):

Uzma Aisha ◽

Qamruzzaman ◽

M. Z. A. Rafiquee

Keyword(s):

Cetyltrimethylammonium Bromide ◽

Binding Constants ◽

Reaction Rates ◽

Lauryl Sulfate ◽

Micellar Media ◽

First Order Kinetics ◽

Rate Of Reaction ◽

Colloidal Mno2 ◽

Kinetics Of ◽

Kinetics Of Reduction

The kinetics of the reduction of colloidal MnO2 by glyphosate has been investigated spectrophotometrically in an aqueous and micellar (cetyltrimethylammonium bromide, sodium lauryl sulfate) media. The reaction follows first-order kinetics with respect to colloidal MnO2 in both the aqueous and micellar media. The rate of oxidation increases with increase in [glyphosate] in the lower concentration range but becomes independent at its higher concentrations. The addition of both the anionic (NaLS) and cationic (CTAB) micelles increased the rate of reduction of colloidal MnO2 by glyphosate while the nonionic TX-100 micelles did not influence the rate of reaction. In both aqueous and micellar media, the oxidation of glyphosate occurs through its adsorption over colloidal MnO2 surface. The reaction in micellar media was treated by considering the pseudophase model. The values of reaction rates and binding constants in the presence of micelles were determined.

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Octahedral cobalt(III) complexes of the chloropentammine type. XIX. The preparation, properties, and reactions of some Chlorobenzylaminebis-(ethylenediamine)cobalt(III) salts and related complexes

Australian Journal of Chemistry ◽

10.1071/ch9691869 ◽

1969 ◽

Vol 22 (9) ◽

pp. 1869 ◽

Cited By ~ 3

Author(s):

SC Chan ◽

OW Lau

Keyword(s):

Rate Constants ◽

Open Chain ◽

First Order ◽

Benzyl Radical ◽

Order Rate ◽

Visible Spectra ◽

Rate Of Reaction ◽

Inductive Effects ◽

Steric Factors ◽

Hydrolysis Of

Salts of one isomeric series of chlorobenzylaminebis(ethylenediamine)- cobalt-(III) type of cations have been prepared using a variety of benzylamine derivatives as ligands. They are tentatively assigned a cis-configuration on the basis of their visible spectra. The first- order rate constants for their solvolytic aquation have been measured. Both resonance contributions and steric factors from the benzyl radical, as well as inductive effects of its substituents, all have negligibly small influences on the rate of reaction. The second-order rate constants for the hydrolysis of these cations by base have also been determined. The labilizing powers of the benzylamine ligands in this reaction are very similar to those of open-chain aliphatic amines, and significantly different from those of aromatic amines. To see if reactivities depend on the distance of separation between cobalt and the benzene ring, the experiments are extended to the chloro(β- phenylethylamine)bis(ethylenediamine)cobalt(III) type of complexes.

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Phototransformations of non-toxic antioxidants, the derivatives of 1,2-dihydroquinolines, in homogeneous and micellar solutions

International Journal of Photoenergy ◽

10.1155/s1110662x99000069 ◽

1999 ◽

Vol 1 (1) ◽

pp. 31-34 ◽

Cited By ~ 1

Author(s):

T. D. Nekipelova

Keyword(s):

Organic Solvents ◽

Rate Constant ◽

Micellar Catalysis ◽

Alkaline Solutions ◽

Direct Reaction ◽

Micellar Solutions ◽

Transient Species ◽

First Order ◽

Order Rate ◽

Aminyl Radicals

Reactions of transient species photogenerated from 6-R-2,2,4-trimethyl-1,2-dihydroquinolines (TMDQ) are very sensitive to medium variation. In anhydrous organic solvents, aminyl radicals were generated. They decay in the reaction of dimerization with the second-order rate constant decreasing in a row heptane>benzene>2-propanol. When passing from organic solvents to water, methanol, and water-alcohol solutions, the kinetics and the direction of the reaction crucially change. As a result of the photolysis, the product of the addition of a solvent to the double bond of heterocycle, 4-hydroxy- or 4-methoxy-6-R-2,2,4- tetramethyl-1,2,3,4-tetrahydroquinoline is formed in water and methanol, respectively. The transformation is a complex reaction, and the formation of excited transient species is followed by a sequence of first-order and pseudo-first-order reactions. Unlike the photolysis in anhydrous organic solvents, the reaction in water and methanol does not involve aminyl radicals. In aqueous solutions, the first-order rate constants for the decay of transient species are higher in acidic and neutral solutions. At the pH close to pKa of the transient species, it drops, indicating that the neutral form is less reactive. The same product is formed over the whole range of pH. For the anionic surfactant (SDS) in acidic and alkaline solutions, the apparent rate constant in the micellar solutions is lower than that in the aqueous (negative micellar catalysis). At the medium pH, a positive micellar catalysis is observed, and the rate constant of the decay depends linearly on the concentration of TMDQ in the micelles, indicative of the direct reaction between TMDQ and the cationic transient species.

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A kinetic standard for precise calibration of spectrophotometer cell temperature.

Clinical Chemistry ◽

10.1093/clinchem/27.5.753 ◽

1981 ◽

Vol 27 (5) ◽

pp. 753-755 ◽

Cited By ~ 3

Author(s):

P A Adams ◽

M C Berman

Keyword(s):

Temperature Dependence ◽

Rate Constants ◽

Cell Temperature ◽

First Order ◽

Order Rate ◽

Acid Catalyzed ◽

Pseudo First Order ◽

Hydrolysis Of

Abstract We describe a simple, highly reproducible kinetic technique for precisely measuring temperature in spectrophotometric systems having reaction cells that are inaccessible to conventional temperature probes. The method is based on the temperature dependence of pseudo-first-order rate constants for the acid-catalyzed hydrolysis of N-o-tolyl-D-glucosylamine. Temperatures of reaction cuvette contents are measured with a precision of +/- 0.05 degrees C (1 SD).

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Kinetics of thiamin cleavage by sulphite

Biochemical Journal ◽

10.1042/bj1130611 ◽

1969 ◽

Vol 113 (4) ◽

pp. 611-615 ◽

Cited By ~ 22

Author(s):

J. Leichter ◽

M. A. Joslyn

Keyword(s):

Aqueous Solutions ◽

Rate Constant ◽

Sulphur Dioxide ◽

First Order ◽

Ph Values ◽

Rate Of Reaction ◽

Kinetics Of

Results are presented on the rate of thiamin cleavage by sulphite in aqueous solutions as affected by temperature (20–70°), pH(2·5–7·0), and variation of the concentration of either thiamin (1–20μm) or sulphite (10–5000μm as sulphur dioxide). Plots of the logarithm of percentage of residual thiamin against time were found to be linear and cleavage thus was first-order with respect to thiamin. At pH5 the rate was also found to be proportional to the sulphite concentration. In the pH region 2·5–7·0 at 25° the rate constant was 50m−1hr.−1 at pH5·5–6·0, and decreased at higher or lower pH values. The rate of reaction increased between 20° and 70°, indicating a heat of activation of 13·6kcal./mole.

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The mechanism of the oxidation of thiocyanate ion by peroxomonosulphate in aqueous solution. II. Kinetics of the reaction

Australian Journal of Chemistry ◽

10.1071/ch9661365 ◽

1966 ◽

Vol 19 (8) ◽

pp. 1365 ◽

Cited By ~ 4

Author(s):

RH Smith ◽

IR Wilson

Keyword(s):

Aqueous Solution ◽

Initial Rate ◽

Stopped Flow ◽

Thiocyanate Ion ◽

First Order ◽

Conductance Method ◽

Rate Of Reaction ◽

Kinetics Of

Initial rates of reaction for the above oxidation have been measured by a stopped-flow conductance method. Between pH 2 and 3.6, the initial rate of reaction, R, is given by the expression R{[HSO5-]+[SCN-]} = {kb+kc[H+]}[HSO5-]0[SCN-]20+ka[H+]-1[HSO5]20[SCN-]0 As pH increases, there is a transition to a pH-independent rate, first order in each thiocyanate and peroxomonosulphate concentrations.

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