Oxidation process and kinetics of bromothymol blue by alkaline permanganate

2020 ◽  
Author(s):  
Ahmed F. Al‐Hossainy ◽  
Samia M. Ibrahim
Keyword(s):  
Oxidation Process ◽  
Bromothymol Blue ◽  
Alkaline Permanganate ◽  
Kinetics Of

New Insights into the Kinetics of the Gas-Phase Oxidation of Hexafluoropropene

2016 ◽  
Vol 41 (4) ◽  
pp. 418-427 ◽  
Author(s):  
David Lokhat ◽  
Maciej Starzak ◽  
Deresh Ramjugernath
Keyword(s):  
Gas Phase ◽  
Oxidation Process ◽  
Flow Reactor ◽  
Packed Column ◽  
Phase Reaction ◽  
Analytical Technique ◽  
Tubular Flow Reactor ◽  
Gas Phase Oxidation ◽  
Tubular Flow ◽  
Kinetics Of

The gas-phase reaction of hexafluoropropene and molecular oxygen was investigated in a tubular flow reactor at 450 kPa and within a temperature range of 463–493 K using HFP/O2 mixtures containing 20–67% HFP on a molar basis. Capillary and packed column chromatography served as the main analytical technique. The reaction yielded HFPO, COF2, CF3COF, C2F4 and c-C3F6 as gas-phase products. High molecular weight oligomers were also formed. The oligomers were found to have a polyoxadifluoromethylene structure according to elemental and 19F NMR analysis. At 493 K HFP is proposed to undergo oxygen-mediated decomposition to difluorocarbene radicals, yielding greater quantities of difluorocarbene recombination products. Kinetic parameters for a revised model of the oxidation process were identified through least squares analysis of the experimental data.

scholarly journals Development and Validation of Stability-Indicating HPLC Methods for the Estimation of Lomefloxacin and Balofloxacin Oxidation Process under ACVA, H2O2, or KMnO4 Treatment. Kinetic Evaluation and Identification of Degradation Products by Mass Spectrometry

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5251
Author(s):  
Barbara Żuromska-Witek ◽  
Paweł Żmudzki ◽  
Marek Szlósarczyk ◽  
Anna Maślanka ◽  
Urszula Hubicka
Keyword(s):  
Room Temperature ◽  
Oxidation Process ◽  
Degradation Products ◽  
Isocratic Elution ◽  
Kinetic Evaluation ◽  
Stability Indicating ◽  
Ich Guidelines ◽  
Azo Initiator ◽  
Development And Validation ◽  
Kinetics Of

The oxidation of lomefloxacin (LOM) and balofloxacin (BAL) under the influence of azo initiator of radical reactions of 4,4′-azobis(4-cyanopentanoic acid) (ACVA) and H2O2 was examined. Oxidation using H2O2 was performed at room temperature while using ACVA at temperatures: 40, 50, 60 °C. Additionally, the oxidation process of BAL under the influence of KMnO4 in an acidic medium was investigated. New stability-indicating HPLC methods were developed in order to evaluate the oxidation process. Chromatographic analysis was carried out using the Kinetex 5u XB—C18 100A column, Phenomenex (Torrance, CA, USA) (250 × 4.6 mm, 5 μm particle size, core shell type). The chromatographic separation was achieved while using isocratic elution and a mobile phase with the composition of 0.05 M phosphate buffer (pH = 3.20 adjusted with o-phosphoric acid) and acetonitrile (87:13 v/v for LOM; 80:20 v/v for BAL). The column was maintained at 30 °C. The methods were validated according to the ICH guidelines, and it was found that they met the acceptance criteria. An oxidation process followed kinetics of the second order reaction. The most probable structures of LOM and BAL degradation products formed were assigned by the UHPLC/MS/MS method.

Point Defect Injection Kinetics by N2O Oxidation of Silicon

1997 ◽  
Vol 469 ◽  
Author(s):  
C. Tsamis ◽  
D. N. Kouvatsos ◽  
D. Tsoukalas
Keyword(s):  
Point Defect ◽  
High Temperatures ◽  
Point Defects ◽  
Silicon Substrate ◽  
Oxidation Process ◽  
Stacking Faults ◽  
Defect Injection ◽  
Dry Oxidation ◽  
Kinetics Of

ABSTRACTThe influence of N2O oxidation of silicon on the kinetics of point defects at high temperatures is investigated. Oxidation Stacking Faults (OSF) are used to monitor the interstitials that are generated during the oxidation process. We show that at high temperatures (1050°-1150°C) the supersaturation of self-interstitials in the silicon substrate is enhanced when oxidation is performed in an N2O ambient compared to 100% dry oxidation. This behavior is attributed to the presence of nitrogen at the oxidizing interface. However, at lower temperatures this phenomenon is reversed and oxidation in N2O ambient leads to reduced supersaturation ratios.

Thermodynamics and kinetics of FeO transferred to Fe3O4 in modified nickel slag during molten oxidation process

2019 ◽  
Vol 6 (9) ◽  
pp. 096551
Author(s):  
Yingying Shen ◽  
Junkai Chong ◽  
Ziniu Huang ◽  
Jianke Tian ◽  
Wenjuan Zhang ◽  
...  
Keyword(s):  
Oxidation Process ◽  
Thermodynamics And Kinetics ◽  
Kinetics Of

Kinetics and mechanistic study of the ruthenium(III) catalyzed oxidative deamination and decarboxylation of L-valine by alkaline permanganate

2001 ◽  
Vol 79 (12) ◽  
pp. 1926-1933 ◽  
Author(s):  
Dinesh C Bilehal ◽  
Raviraj M Kulkarni ◽  
Sharanappa T Nandibewoor
Keyword(s):  
Ionic Strength ◽  
Alkaline Medium ◽  
Activation Parameters ◽  
Solvent Polarity ◽  
Mechanistic Study ◽  
Reaction Products ◽  
Order Dependence ◽  
Alkaline Permanganate ◽  
Kinetics Of ◽  
Catalyzed Oxidation

The kinetics of ruthenium(III) catalyzed oxidation of L-valine by permanganate in alkaline medium at a constant ionic strength has been studied spectrophotometrically. The reaction between permanganate and L-valine in alkaline medium exhibits 2:1 stoichiometry (KMnO4:L-valine). The reaction shows first-order dependence on the concentration of permanganate and ruthenium(III) and less than unit-order dependence on the concentrations of L-valine and alkali. The reaction rate increases both with an increase in ionic strength and a decrease in solvent polarity of the medium. Initial addition of reaction products did not significantly affect the rate. A mechanism involving the formation of a complex between catalyst and substrate has been proposed. The activation parameters were computed with respect to the slowest step of the mechanism.Key words: oxidation, L-valine, catalysis, ruthenium(III), kinetics.

Kinetics and Mechanism of Oxidation of Selenium(IV) by Permanganate Ion in Aqueous Perchlorate Solutions

1993 ◽  
Vol 58 (3) ◽  
pp. 538-546 ◽  
Author(s):  
Refat M. Hassan ◽  
Sahr A. El-Gaiar ◽  
Abd El-Hady M. El-Summan
Keyword(s):  
Reaction Mechanism ◽  
Reaction Rate ◽  
Oxidation Process ◽  
Selenium Dioxide ◽  
Order Reaction ◽  
Acid Solutions ◽  
First Order ◽  
Acid Catalyzed ◽  
Mechanism Of Oxidation ◽  
Kinetics Of

The kinetics of permanganate oxidation of selenium dioxide in perchloric acid solutions at a constant ionic strength of 2.0 mol dm-3 has been investigated spectrophotometrically. A first-order reaction in [MnO4-] and fractional order with respect to selenium(IV) were observed. The reaction rate was found to be pH-independent at lower acid concentrations ([H+] < 0.5 mol dm-3) and was acid-catalyzed beyond this range. Addition of Mn2+ and F- ions leads to the prediction that MnO4- is the sole reactive species in the oxidation process. A tentative reaction mechanism consistent with the reaction kinetics has been proposed.

Inhibition of Mordant Dyes Destruction in Fenton Reaction

2013 ◽  
Vol 821-822 ◽  
pp. 493-496 ◽  
Author(s):  
Jian Hua Ran ◽  
Irina Shushina ◽  
Viktoriia Priazhnikova ◽  
Felix Telegin
Keyword(s):  
Complex Formation ◽  
Dissociation Constant ◽  
Spectral Method ◽  
Fenton Reaction ◽  
Oxidation Process ◽  
Hydroxyl Group ◽  
Spectral Studies ◽  
Iron Ions ◽  
Relationship Of ◽  
Kinetics Of

Kinetics of destruction of acid and mordant dyes in Fenton reaction was investigated by the use of spectral method. Inhibition of destruction of some mordant dyes was observed. A simple theory for describing this phenomenon was proposed, which is based on consideration of participation of iron ions in complex formation with mordant dye ligands. By the use of chemical software JChem (ChemAxon) it was found that mordant dye exhibiting stability in Fenton solution bears hydroxyl group with high dissociation constant, pK=2,57. On the contrary, another dye bearing hydroxyl with low dissociation constant, pK1=6,65, does not exhibit any inhibition in oxidation process. UV-Vis spectral studies of the complexes of several mordant dyes prove correlations with their stability in Fenton reaction, however some dyes exhibit no relationship of this kind.

Oxidation Behavior of As-Forged Fe-25wt%Cr Alloys at 1100°C in Air

2011 ◽  
Vol 695 ◽  
pp. 348-352 ◽  
Author(s):  
Hui Xie ◽  
Lei Jia ◽  
Xiao Feng Zhang ◽  
Zhen Lin Lu
Keyword(s):  
Oxidation Behavior ◽  
Oxidation Process ◽  
Hot Forging ◽  
Oxygen Ions ◽  
Second Stage ◽  
Parabolic Law ◽  
Transport Velocity ◽  
Fast Transport ◽  
Kinetics Of ◽  
Oxidation Scale

Fe-25wt%Cr alloys were fabricated by combining Powder Metallurgy (PM) with hot-forging treatment, and their oxidation behavior at 1100°C in air was investigated systematically by using XRD, SEM and EDS, respectively. The results showed that a composite oxidation scale containing both Cr2O3and FeCr2O4formed on the surface of as-forged Fe-25wt%Cr alloys after oxidation at 1100°C in air for 100 hours. The oxidation process of Fe-Cr alloys could be obviously divided into two different stages, and the kinetics of two-stage oxidation agreed well with the parabolic law. The first could be corresponding to the formation of protective Cr2O3layer, while the second could be thought as the growth of FeCr2O4and the further oxidation of the inner Cr2O3oxidation scale. The faster oxidation rate in the second stage could be attributed to both the diffusion of iron ions rapider than that of Cr in the Cr2O3layer and the fast transport velocity of oxygen ions along the cracks.

Kinetic study of lipid oxidation in roasted coffee

1998 ◽  
Vol 4 (1) ◽  
pp. 67-73 ◽  
Author(s):  
M.D. Ortolá ◽  
C.L. Gutiérrez ◽  
A. Chiralt ◽  
P. Fito
Keyword(s):  
Moisture Content ◽  
Lipid Oxidation ◽  
Oxidation Process ◽  
Storage Temperature ◽  
Important Change ◽  
Second Step ◽  
Initiation Mechanism ◽  
Experimental Values ◽  
Second Period ◽  
Kinetics Of

The kinetics of lipid oxidation in ground roast Arabica coffee from Colombia stored under different conditions were studied. Rancidity was controlled by the analysis of the peroxide value at 30-day intervals. The influence of moisture content (26 and 43 g/kg), storage temperature (5, 25 and 35 °C) and packaging conditions (with non-sealed bags, under vacuum, 35 mbar, and packed under CO2 atmosphere) on the kinetics was determined. Experimental values were fitted with a kinetic model for the mechanism of lipid oxidation. Lipid oxidation is described by two steps, which implies a monomolecular and a bimolecular initiation mechanism for the first and second period respectively. The kinetic constants showed that the plastificant effect of water and CO2 lead to an important change in the reactants' mobility within the temperature range. However, the rise in moisture content seems to protect the product from formation of the peroxide. Furthermore, this effect is more important in the second step of the oxidation process.

scholarly journals Study on the thermal kinetics of anthracite oxidation induced by water and associated pyrite

2020 ◽  
Author(s):  
Caiping Wang ◽  
Xiadan Duan ◽  
Zujin Bai ◽  
Yang Xiao ◽  
Jun Deng
Keyword(s):  
Coal Sample ◽  
Spontaneous Combustion ◽  
Oxidation Process ◽  
Great Influence ◽  
Oxygen Absorption ◽  
Heating Rates ◽  
Temperature Oxidation ◽  
Mechanism Model ◽  
Gain Stage ◽  
Kinetics Of

Abstract Pyrite and water in coal have considerable influence on coal spontaneous combustion and threaten the safety of mine production gravely. To reveal the influence mechanism of water and associated pyrite on oxidation kinetics of coal–oxygen composite reaction, the pyrite of 0%, 1%, 2%, 4%, 6% and the moisture of 1%, 5%, 10%, 15% and 20% were mixed with the coal samples to obtain 25 coal samples. Thermogravimetric analysis technology was conducted to explore the changes of mass and characteristic temperatures of coal samples treated with water and associated pyrite during the low–temperature oxidation, and kinetic analysis of the oxidation process was discussed based on multiple heating rates(5 °C/min, 10 °C/min and15 °C/min).The results show that water and associated pyrite had a great influence on coal in oxygen absorption and weight gain stage ( T 3 ~ T 5 ), and there was a proportion range with the largest synergistic oxidation contribution. The apparent activation energy of the coal sample appeared changes, but the mechanism model did not, indicating that water and pyrite could affect the oxidation process of the coal sample externally. When water and associated pyrite exhibit synergistic interaction, there have a range that water was 10~15% and associate pyrite was 2~4% had the largest promotion and contribution to anthracite oxidation. The results have important scientific value and practical guiding significance for the further study on prediction, prevention and control of high sulfur anthracite spontaneous combustion.

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