Reaction Kinetics and Critical Phenomena:  Rates of Some First Order Gas Evolution Reactions in Binary Solvents with a Consolute Point

2005 ◽  
Vol 109 (21) ◽  
pp. 4750-4757 ◽  
Author(s):  
Yeong Woo Kim ◽  
James K. Baird
Keyword(s):  
Reaction Kinetics ◽  
Critical Phenomena ◽  
Binary Solvents ◽  
Gas Evolution ◽  
First Order ◽  
Consolute Point

Photocolouration of 2,4,4,6-Tetraaryl-4H-pyrans and Their Heteroanalogues: Importance of Hypervalent Photoisomers

1995 ◽  
Vol 60 (10) ◽  
pp. 1621-1633 ◽  
Author(s):  
Stanislav Böhm ◽  
Mojmír Adamec ◽  
Stanislav Nešpůrek ◽  
Josef Kuthan
Keyword(s):  
Reaction Kinetics ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Theoretical Data ◽  
Order Reaction ◽  
Bleaching Process ◽  
First Order ◽  
Photodegradation Products ◽  
Hypervalent Molecules

Molecular geometries of 2,4,4,6-tetraphenyl-4H-pyran (Ia), 4,4-(biphenyl-2,2e-diyl)-2,6-diphenyl-4H-pyran (Ib) and their heterocyclic isomers II-V were optimized by the PM3 method and used for the calculation of electronic absorption spectra by the CNDO/S-CI procedure. Comparison of the theoretical data with experimental UV-VIS absorption spectra made possible to select hypervalent molecules IIIa, IIIb, IVa and IVb being responsible for the photocolouration of 4H-pyrans Ia, Ib, while compounds Va, Vb, VI and VII come into account as possible photodegradation products. The bleaching process of the UV illuminated compound Ia is analyzed in terms of dispersive first-order reaction kinetics.

scholarly journals KINETIC INVESTIGATION OF PROPANE DISAPPEARANCE AND PROPENE FORMATION IN PROPANE OXIDATION ON DILUTED AND LEACHED MoVTeNb CATALYST

2010 ◽  
Vol 10 (2) ◽  
pp. 172-176
Author(s):  
Restu Kartiko Widi
Keyword(s):  
Reaction Kinetics ◽  
Partial Order ◽  
Reaction Order ◽  
Propane Oxidation ◽  
Kinetic Investigation ◽  
Formation Kinetic ◽  
Kinetic Reaction ◽  
First Order ◽  
Langmuir Hinshelwood Mechanism

Reaction kinetics for the oxidation of propane over diluted-leached MoVTeNb is described. This paper is focused on the study of products selectivity profile and determination of the orders of propane disappearance and propene formation. The result shows that selective oxidation of propane to propene over this catalyst follows the Langmuir-Hinshelwood mechanism. The disappearance of propane is first order with respect to hydrocarbon and partial order (0.21) with respect to oxygen. The propene formation is first order with respect to hydrocarbon and not depending on oxygen concentration.   Keywords: propane oxidation, propane disappearance, propene formation, kinetic, reaction order

Pre-Reduction of Chromite by Thermogravimetric (TG) Analysis

2013 ◽  
Vol 760 ◽  
pp. 23-32
Author(s):  
D.M.A. Khan
Keyword(s):  
Reaction Kinetics ◽  
Order Reaction ◽  
First Order Reaction ◽  
Reduction Mechanism ◽  
Muffle Furnace ◽  
Tg Analysis ◽  
First Order ◽  
Single Pellet ◽  
Reduction Smelting

Thermogravimetric experiments on prereduction of single pellet and multiple pellets were conducted in Muffle furnace at 1500oC. Reduction smelting of Chromite in Fe-C melt in TG setup indicates CR is reduced faster than CG and CB. The reduction mechanism takes the path of first order reaction kinetics. Only 50% Cr metallization could be obtained at 1550oC from the reduction smelting experiments.

On the Chemical Reactivity of the Phytochrome Chromophore in the Pr and Pfr Form

1985 ◽  
Vol 40 (3-4) ◽  
pp. 215-218 ◽  
Author(s):  
Fritz Thümmler ◽  
Peter Eilfeld ◽  
Wolfhart Rüdiger ◽  
Doo-Khil Moon ◽  
Pill-Soon Song
Keyword(s):  
Reaction Kinetics ◽  
Rate Constants ◽  
Chemical Reactivity ◽  
Order Reaction ◽  
First Order Reaction ◽  
Limiting Factor ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Pseudo First Order ◽  
The Difference

The reactivity of the phytochrome chromophore and related tetrapyrroles towards ozone and tetranitromethane was investigated. Both oxidizing reagents cause bleaching of the main absorp­tion band of the pigment. The rate constants for this bleaching were determined under conditions of pseudo first order reaction kinetics. The rate constants for the reaction with ozone are similar for native phytochrome and for freely accessible tetrapyrroles (biliverdin, small chromopeptides from phytochrome) indicating that accessibility is not the limiting factor for the reaction with ozone. Under a variety of conditions, the Pfr chromophore reacts by about 10% faster than the Pr chromophore. This may reflect the true difference in reactivity. The rate constants for the reaction with tetranitromethane are much larger for biliverdin, bilirubin and small chromopeptides from phytochrome than for native phytochrome. The limiting factor for this reaction in native phytochrome therefore is the accessibility of the chromophore by the reagent. Previous conclusions on the difference in exposure of the tetrapyrrole chromophore in Pr and Pfr are confirmed.

Interactions of hypochlorite ion and humic acid: photolytic and photocatalytic pathways

2001 ◽  
Vol 44 (5) ◽  
pp. 205-210 ◽  
Author(s):  
D. Gonenç ◽  
M. Bekbolet
Keyword(s):  
Humic Acid ◽  
Reaction Kinetics ◽  
Removal Efficiency ◽  
Photocatalytic Oxidation ◽  
Removal Rate ◽  
Order Reaction ◽  
First Order Reaction ◽  
Acid Oxidation ◽  
First Order ◽  
Toc Removal

Photolytic and photocatalytic interactions of hypochlorite ion and humic acid are investigated under various conditions. Humic acid oxidation by aqueous chlorine under dark conditions are expressed in terms of first order reaction kinetics. Upon irradiation (300 nm < λ < 400 nm), photolysis of aqueous chlorine affect the removal efficiency of humic acid via oxidation. TiO2 sensitised photocatalytic oxidation conditions reveal an increase in the TOC removal rate of humic acid in the presence of aqueous chlorine. Under the specified conditions, increasing the photocatalyst loading up to 1.0 mg/mL markedly increase the TOC removal rate.

Experimental Evaluation of Nonisothermal, First-Order Reaction Kinetics

1995 ◽  
Vol 28 (26) ◽  
pp. 8729-8734 ◽  
Author(s):  
D. J. Robbins ◽  
A. J. Almquist ◽  
D. C. Timm ◽  
J. I. Brand ◽  
R. E. Gilbert
Keyword(s):  
Reaction Kinetics ◽  
Experimental Evaluation ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order
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