Kinetics and Mechanism of Hexachloroiridate(IV) Oxidation of Arsenic(III) in Acidic Perchlorate Solutions

1992 ◽  
Vol 57 (7) ◽  
pp. 1451-1458 ◽  
Author(s):  
Refat M. Hassan
Keyword(s):  
Ionic Strength ◽  
Fractional Order ◽  
Activation Parameters ◽  
Order Reaction ◽  
First Order Reaction ◽  
Intermediate Complex ◽  
Constant Ionic Strength ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Kinetics Of

The kinetics of oxidation of arsenic(III) by hexachloroiridate(IV) at lower acid concentrations and at constant ionic strength of 1.0 mol dm-3 have been investigated spectrophotometrically. A first-order reaction in [IrCl62-] and fractional order with respect to arsenic(III) have been observed. A kinetic evidence for the formation of an intermediate complex between the hydrolyzed arsenic(III) species and the oxidant was presented. The results showed that decreasing the [H+] is accompanied by an appreciable acceleration of the rate of oxidation. The activation parameters have been evaluated and a mechanism consistent with the kinetic results was suggested.

Kinetics and mechanism of oxidation of Chitosan Polysaccharide by Permanganate Ion in Aqueous Perchlorate Solutions

2003 ◽  
Vol 2003 (4) ◽  
pp. 182-183 ◽  
Author(s):  
Gamal Abdel-Whab Ahmed ◽  
Khalid Suliman Khairou ◽  
Refat Moustafa Hassan
Keyword(s):  
Ionic Strength ◽  
Second Order ◽  
Kinetics And Mechanism ◽  
Constant Ionic Strength ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Mechanism Of Oxidation ◽  
Kinetics Of ◽  
Overall Kinetics ◽  
Permanganate Ion

The kinetics of oxidation of chitosan as polysaccharide by permanganate in aqueous perchlorate media at a constant ionic strength was found to have second-order overall kinetics and to be first-order in the concentration of both reactants, the results obtained showed that the reaction is acid catalysed.

CYCLOADDITIONS: X. KINETICS OF THE THERMAL DECARBONYLATION OF DICYCLOPENTADIENE-1.8-DIONE

1966 ◽  
Vol 44 (17) ◽  
pp. 2051-2056 ◽  
Author(s):  
John E. Baldwin
Keyword(s):  
Carbon Monoxide ◽  
Activation Parameters ◽  
Order Reaction ◽  
First Order Reaction ◽  
Kcal Mole ◽  
First Order ◽  
Kinetics Of ◽  
Thermal Decarbonylation

The thermal cycloelimination of carbon monoxide from dicyclopentadiene-1,8-dione is a kinetically well-behaved first-order reaction. At 380 °K the activation parameters for the process are ΔH≠ = 34.5 ± 0.8 kcal mole−1 and ΔS≠ = +9.8 ± 2.3 e.u. mole−1. Application of the theoretical proposals of Woodward and Hoffmann indicates that this necessarily disrotatory decarbonylation may be concerted.

The Kinetics of Glucose Decomposition with Sulfate Reduction in the Anaerobic Fluidized Bed Reactor

1993 ◽  
Vol 28 (2) ◽  
pp. 135-144 ◽  
Author(s):  
S. Matsui ◽  
R. Ikemoto Yamamoto ◽  
Y. Tsuchiya ◽  
B. Inanc
Keyword(s):  
Sulfate Reduction ◽  
Fluidized Bed ◽  
Kinetic Equations ◽  
Fluidized Bed Reactor ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Glucose Decomposition ◽  
Reaction Equations ◽  
Kinetics Of

Using a fluidized bed reactor, experiments on glucose decomposition with and without sulfate reduction were conducted. Glucose in the reactor was mainly decomposed into lactate and ethanol. Lactate was mainly decomposed into propionate and acetate, while ethanol was decomposed into propionate, acetate, and hydrogen. Sulfate reduction was not involved in the decomposition of glucose, lactate, and ethanol, but was related to propionate and acetate decomposition. The stepwise reactions were modeled using either a Monod expression or first order reaction kinetics in respect to the reactions. The coefficients of the kinetic equations were determined experimentally. The modified Monod and first order reaction equations were effective at predicting concentrations of glucose, lactate, ethanol, propionate, acetate, and sulfate along the beight of the reactor. With sulfate reduction, propionate was decomposed into acetate, while without sulfate reduction, accumulation of propionate was observed in the reactor. Sulfate reduction accelerated propionate conversion into acetate by decreasing the hydrogen concentration.

Direct Method for Determining Inorganic Phosphate in Serum with the "CentrifiChem"

1972 ◽  
Vol 18 (3) ◽  
pp. 263-265 ◽  
Author(s):  
John A Daly ◽  
Gerhard Ertingshausen
Keyword(s):  
Inorganic Phosphate ◽  
Direct Method ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Kinetics Of ◽  
A Direct Method

Abstract A direct method was developed for determining inorganic phosphate in serum, which requires only a single reagent addition. The method quantitates the unreduced phosphomolybdate heteropolyacid at 340 nm and is linear to at least 10 mg of phosphate per 100 ml. Only 10 µl of serum is required. The unique blanking capabilities of centrifugal analyzers permit the "on run" elimination of serum and reagent background absorbances, which are automatically subtracted. Data on precision, correlation, and recovery are presented. Kinetics of the reaction were studied, and theoretical limits of automatic blanking when applied to a first-order reaction are discussed.

Development of Torrefaction Kinetics for British Columbia Softwoods

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Jianghong Peng ◽  
Xiaotao T. Bi ◽  
Jim Lim ◽  
Shabab Sokhansanj
Keyword(s):  
British Columbia ◽  
Weight Loss ◽  
Kinetic Model ◽  
Residence Time ◽  
Order Reaction ◽  
First Order Reaction ◽  
Chemical Components ◽  
First Order ◽  
One Step ◽  
Kinetics Of

Torrefaction is a thermal treatment without air or oxygen in the temperature range of 473-573 K. The pyrolysis kinetics of three chemical components (cellulose, hemicelluloses, and lignin) and wood at low temperatures of relevance to torrefaction conditions have been reviewed. A series of thermogravimetric (TG) experiments have been carried out to study the intrinsic torrefaction kinetics of major chemical components and British Columbia (BC) softwoods. The weight loss during BC softwood torrefaction was found to be mainly associated with the decomposition of hemicelluloses, although there was also certain degree of decomposition of cellulose and lignin. The weight loss of the BC softwoods during torrefaction could be approximately estimated from the chemical composition of wood species and the weight loss data for torrefaction of pure cellulose, hemicelluloses, and lignin, respectively. Based on the fitting of the TG curves of BC softwoods and three chemical components, two different torrefaciton models were proposed. The simple one-step (single-stage) kinetic model with the first order reaction can predict the reaction data reasonably well over the long residence time, with the final sample weight being strongly related to the torrefaction temperature. A two-component and one-step first order reaction kinetic model, on the other hand, gave improved agreement with data over short residence time, and can be used to guide the design and optimization of torrefaction reactors over the weight loss range of 0 to 40% at the temperature range of 533-573 K, which covers the typical range of industrially relevant operations.

Kinetics of Cs adsorption/desorption on granite by a pseudo first order reaction model

2007 ◽  
Vol 275 (3) ◽  
pp. 555-562 ◽  
Author(s):  
Shih-Chin Tsai ◽  
Tsing-Hai Wang ◽  
Yuan-Yaw Wei ◽  
Wen-Chun Yeh ◽  
Yi-Lin Jan ◽  
...  
Keyword(s):  
Reaction Model ◽  
Order Reaction ◽  
First Order Reaction ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Pseudo First Order ◽  
Adsorption Desorption ◽  
Kinetics Of

Synthesizes and Properties Research of a Photochromic Diarylethene Bearing a Hexatomic Ring

2013 ◽  
Vol 830 ◽  
pp. 278-281
Author(s):  
Zhi Yuan Sun ◽  
Wei Wei Geng ◽  
Shou Zhi Pu
Keyword(s):  
Reaction Kinetics ◽  
Fluorescence Intensity ◽  
Uv Light ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Solid Films ◽  
Kinetics Of

A new photochromic diarylethene compound 1-(2-cyan-3-phenyl)-2-[5-(4-cyanobenzene) -2-methyl-3-thienyl] perfluorocyclopentene was synthesized. And their properties inculding photochromis, fluorescence in both hexane and solid films, reaction kinetics of cyclization and cycloreversion were studied. And its absorption maxima were observed at 539 nm in hexane and at 552 nm in PMMA films, respectively, upon irradiation with 313 nm UV light. The fluorescence intensity of diarylethene decreased upon irradiation with 313 nm UV light. Besides, the cyclization and cycloreversion processes of the compound were determined to be the zeroth and first order reaction by UV-Vis spectra, respectively.

PHOTOCHROMIC KINETICS OF ASYMMETRICAL DIARYLETHENES IN DIFFERENT SOLVENTS AND IN PMMA FILMS

2008 ◽  
Vol 15 (01n02) ◽  
pp. 145-151 ◽  
Author(s):  
MIN LI ◽  
SHOUZHI PU ◽  
CHUNHONG ZHENG ◽  
MINGBIAO LUO ◽  
ZHANGGAO LE
Keyword(s):  
Position Effect ◽  
Phenyl Group ◽  
Solvent Polarity ◽  
Reaction Rates ◽  
Order Reaction ◽  
Para Position ◽  
First Order Reaction ◽  
First Order ◽  
Kinetics Of

Three new asymmetric photochromic diarylethenes bearing fluorine atoms at the ortho-, meta-, or para-position of one terminal phenyl group were synthesized, and their photochromism and kinetics of the photochromic cyclization/cycloreversion both in different solvents and in PMMA films were investigated. The results showed that the cyclization/cycloreversion process of these compounds were determined to be zeroth/first order reaction, and the reaction rates (k) were obtained from the slope of every line. The substituent position effect on the cycloreversion process of the three compounds was remarkable and the solvent polarity enhanced this effect. The values of reaction rates in PMMA films were quite different from those in solvents indicating that the kinetics processes of the three compounds taking place in PMMA films differs from the same processes occurring in common solvent.

scholarly journals Kinetics of irreversible enzyme inhibition by an unstable inhibitor

1974 ◽  
Vol 141 (2) ◽  
pp. 601-603 ◽  
Author(s):  
Emmanuel T. Rakitzis
Keyword(s):  
Methyl Ester ◽  
Enzyme Inhibition ◽  
Cathepsin D ◽  
Fluorescein Isothiocyanate ◽  
Order Reaction ◽  
Enzyme Inactivation ◽  
First Order Reaction ◽  
Mathematical Treatment ◽  
First Order ◽  
Kinetics Of

A mathematical treatment for the general case of enzyme inactivation by an inhibitor that breaks down in solution in a first-order reaction is presented. Cathepsin D was inactivated by fluorescein isothiocyanate with a Ki of 4.47μm. Kinetic constants were also determined for the inactivation of cathepsin D by 1,1-bis(diazoacetyl)-2-phenylethane, and the inactivation of pepsin C by diazoacetyl-dl-norleucine methyl ester.

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