The Formation and Reactions of Disulfide Radical Anions in Aqueous Solution

1975 ◽  
Vol 53 (21) ◽  
pp. 3153-3157 ◽  
Author(s):  
Tzu-Lin Tung ◽  
John A. Stone
Keyword(s):  
Aqueous Solution ◽  
Radical Anion ◽  
Flash Photolysis ◽  
Ph Dependence ◽  
Order Reaction ◽  
Radical Anions ◽  
Second Order Reaction ◽  
Low Concentration ◽  
First Order ◽  
Rate Of Decay

Transient disulfide radical anions have been produced by flash photolysis. Cyclic anions decay only by second order reaction as opposed to the first order decay found for linear ones at low concentration. Linear disulfides, except oxidized penicillamine, increase the rate of decay of the cystine radical anion. The pH dependence of the reaction with cystine suggests that the disulfide radical anion is an electrophile.

Stability of radical anions derived from substituted 5-nitrofurans investigated by ESR spectroscopy

1985 ◽  
Vol 50 (7) ◽  
pp. 1594-1601 ◽  
Author(s):  
Jiří Klíma ◽  
Larisa Baumane ◽  
Janis Stradinš ◽  
Jiří Volke ◽  
Romualds Gavars
Keyword(s):  
Radical Anion ◽  
High Stability ◽  
Esr Spectroscopy ◽  
Reaction Path ◽  
Order Reaction ◽  
Second Order ◽  
Radical Anions ◽  
Second Order Reaction ◽  
Unpaired Electron Density ◽  
The Stability

It has been found that the decay in dimethylformamide and dimethylformamide-water mixtures of radical anions in five of the investigated 5-nitrofurans is governed by a second-order reaction. Only the decay of the radical anion generated from 5-nitro-2-furfural III may be described by an equation including parallel first- and second-order reactions; this behaviour is evidently caused by the relatively high stability of the corresponding dianion, this being an intermediate in the reaction path. The presence of a larger conjugated system in the substituent in position 2 results in a decrease of the unpaired electron density in the nitro group and, consequently, an increase in the stability of the corresponding radical anions.

scholarly journals Photocatalytic degradation of sulfamethazine in aqueous solution using ZnO with different morphologies

2018 ◽  
Vol 5 (4) ◽  
pp. 171457 ◽  
Author(s):  
Zhigang Yi ◽  
Juan Wang ◽  
Tao Jiang ◽  
Qiong Tang ◽  
Ying Cheng
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Degradation ◽  
Reaction System ◽  
Degradation Pathway ◽  
Order Reaction ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Different Shapes ◽  
Pseudo First Order ◽  
Release Ratio

In this study, photocatalytic experiments of 20 mg l −1 sulfamethazine (SMN) in aqueous solution containing ZnO with different morphologies, tetra-needle-like ZnO (T-ZnO), flower-like ZnO (F-ZnO) and nanoparticles ZnO (P-ZnO), were performed. The results indicated that photocatalytic degradation of SMN was effective and followed the pseudo-first-order reaction, but the degree of SMN mineralization showed obvious differences using ZnO with different shapes. After 12 h irradiation, 86%, 71% and 50% of the initial total organic carbon was eliminated in SMN suspension containing T-ZnO, F-ZnO and P-ZnO, respectively. The release ratio of sulfur was close to 100% in the presence of T-ZnO, but reached to 86% and 67% in the presence of F-ZnO and P-ZnO, respectively. The release ratio of nitrogen was about 76%, 63% and 40% using T-ZnO, F-ZnO and P-ZnO as photocatalyst, respectively. The morphology of ZnO played an important role in determining its catalytic activity. Seven intermediates were observed and identified in the UV/T-ZnO reaction system by LC-MS/MS analysis, and a possible degradation pathway was proposed.

scholarly journals The alcoholysis of 1,2,2-trimethylpropyl-methylfluorophosphonate

2000 ◽  
Vol 65 (12) ◽  
pp. 857-866
Author(s):  
Mladjen Micevic ◽  
Slobodan Petrovic
Keyword(s):  
Kinetic Data ◽  
Reaction Rate ◽  
Frequency Factor ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
Activation Entropy ◽  
Second Order Reaction ◽  
Third Order ◽  
First Order ◽  
Kinetics Of

The alcoholysis of 1,2,2-trimethylpropyl-methylfluorophosphonate (soman) was examined with a series of alkoxides and in corresponding alcohols: methanol, ethanol, 1-propanol, 2-propanol, 2-methoxyethanol and 2-ethoxyethanol. Soman reacts with the used alkoxides in a second order reaction, first order in each reactant. The kinetics of the reaction between 1,2,2-trimethylpropyl-methylfluorophosphonate and ethanol in the presence of diethylenetriamine was also examined. A third order reaction rate constant was calculated, first order in each reactant. The activation energy, frequency factor and activation entropy were determined on the basis of the kinetic data.

scholarly journals Kinetic Analysis of Genipin Degradation in Aqueous Solution

2010 ◽  
Vol 5 (12) ◽  
pp. 1934578X1000501 ◽  
Author(s):  
Paul Slusarewicz ◽  
Keng Zhu ◽  
Tom Hedman
Keyword(s):  
Aqueous Solution ◽  
Kinetic Analysis ◽  
Crosslinking Agent ◽  
Order Reaction ◽  
First Order Reaction ◽  
Protein Crosslinking ◽  
First Order ◽  
Natural Protein ◽  
Phosphate Ions ◽  
Low Toxicity

Degradation of genipin (GP), a low toxicity natural protein crosslinking agent, in aqueous solution was monitored by HPLC at various pH levels. Degradation of GP was consistent with a mechanism consisting of a first order reaction with a reversible first step. Formation of the intermediate was slowest at more neutral pHs while formation of the irreversible product was correlated to increasing alkalinity. Degradation at all pHs was enhanced by the presence of phosphate ions. Degradation of GP most likely proceeds via the reversible opening of the dihydropyran ring by water followed by irreversible polymerization of the intermediate. Degraded solutions containing no detectable GP or intermediate, however, are still capable of crosslinking proteins.

An Investigation into the Conversion of Propylene Glycol to 2,4-dimethyl-1,3-dioxolane over an Acid Catalyst Using Gas Chromatography

2013 ◽  
Vol 850-851 ◽  
pp. 82-85
Author(s):  
Zuo You Zhang ◽  
Hui Chen ◽  
Xia Li ◽  
Zhao Hui Yang ◽  
Bao Chen Liang
Keyword(s):  
Aqueous Solution ◽  
Reaction Rate ◽  
Acid Catalyst ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
Molar Ratio ◽  
Temperature Reaction ◽  
Gas Chromatograph ◽  
Second Order Reaction ◽  
Operational Parameters

In the presence of an acid catalyst, PG react reversibly with acetaldehyde to form 2,4-dim-ethyl-1,3-dioxolane (24DMD). The effects of different operational parameters on PG conversion had been analyzed in paper, parameters included temperature, reaction time, amount of catalyst and aqueous acetaldehyde/PG molar ratio. Under optimal condition, 85% conversion of PG in aqueous solution was achieved within 180 min of reaction. The analysis of PG was conducted by gas chromatograph. Furthermore, reaction followed the second-order reaction kinetics, and the reaction rate constant was found to be 29.68min-1.

Studies in the Vulcanization of Rubber. III—Kinetics of Vulcanization of Rubber with Sulfur and Selenium

1930 ◽  
Vol 3 (4) ◽  
pp. 650-659
Author(s):  
John T. Blake
Keyword(s):  
Molecular Weight ◽  
Order Reaction ◽  
Order Equation ◽  
Second Order Reaction ◽  
Experimental Conditions ◽  
Mathematical Basis ◽  
First Order ◽  
Kinetics Of ◽  
Kinetics Of Vulcanization

Abstract A procedure for the determination of combined selenium in rubber has been evolved. The rate of combination of selenium and rubber has been ascertained under certain conditions and shown to follow a first-order equation. A minimum value for the molecular weight of rubber has been estimated. The formation of hard rubber under chosen experimental conditions has been put on a mathematical basis and has been shown to follow a second-order reaction. The soft- and hard-rubber reactions have been shown qualitatively to be successive reactions and the function of accelerators has been discussed. The theory explains the anomalous results obtained by previous investigators.

scholarly journals Preparation of wrapped nZVI particles and their application for the degradation of trichloroethylene (TCE) in aqueous solution

2015 ◽  
Vol 5 (3) ◽  
pp. 335-343 ◽  
Author(s):  
Wenjing Fan ◽  
Yue Cheng ◽  
Shuzhen Yu ◽  
Xiaofeng Fan ◽  
Yaqian Deng
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Methyl Cellulose ◽  
Order Reaction ◽  
Phase Reaction ◽  
Solution Ph ◽  
First Order ◽  
Structure And Morphology ◽  
Transmission Electron ◽  
Optimal Ph

Three types of wrappped nanoscale zero-valent iron (W-nZVI) with different coatings including agar, starch, and carboxyl methyl cellulose, were synthesized using a rheological phase reaction method. The structure and morphology of W-nZVI particles were characterized by scanning electron microscopy and transmission electron microscopy. Batch degradation experiments exhibited that W-nZVI dosage, initial trichloroethylene (TCE) concentration and solution pH had significant effects on TCE dechlorination. Experimental results proved that the highest dechlorination efficiency was obtained within 320 minutes for 10 mg/L of TCE at the optimal pH of 5.0 and W-nZVI dosage of 0.5 g/L. Kinetic study revealed that TCE dechlorination by W-nZVI in aqueous solution obeyed the quasi-first-order reaction kinetics. The product after the reaction could be easily separated by the permanent magnet for re-use.

Phenol Removal from Aqueous Solution by Microwave Combined with Granular Active Carbon

2013 ◽  
Vol 807-809 ◽  
pp. 1543-1546
Author(s):  
Dong Yuan ◽  
Da You Fu ◽  
Ming Sheng Gui ◽  
Wen Yuan Tan
Keyword(s):  
Aqueous Solution ◽  
Active Carbon ◽  
Microwave Power ◽  
Irradiation Time ◽  
Removal Rate ◽  
Order Reaction ◽  
Phenol Removal ◽  
Effective Factors ◽  
First Order ◽  
Granular Active Carbon

The removal of phenol from aqueous solution was evaluated by using microwave technique assisted with active carbon. The effective factors such as the concentration of phenol , active carbon dosage, microwave power and irradiation time on the removal rate were investigated. When the concentration of phenol was 150 mg/l, active carbon dosage was 6 g/l, microwave power was 500 W, and irradiation time was 8 min, the removal ratio of phenol reached 95. 03%. The research on kinetics suggested that the process of treatment accords to the first-order reaction.

Electrochemical Degradation of RDX in Aqueous Solution at Constructed Sb-Doped SnO2 Anode

2011 ◽  
Vol 396-398 ◽  
pp. 1803-1806
Author(s):  
Yong Chen ◽  
Lei Hong ◽  
Wei Shi ◽  
Wei Qing Han ◽  
Lian Jun Wang
Keyword(s):  
Aqueous Solution ◽  
Current Density ◽  
Order Reaction ◽  
Electrochemical Degradation ◽  
Kinetics Analysis ◽  
Pseudo First Order Reaction ◽  
Initial Concentration ◽  
First Order ◽  
Sno2 Electrode ◽  
Pseudo First Order

The constructed Sb-doped SnO2 electrode was obtained for electrochemical degradation of RDX. The influences of current density and initial concentration of RDX on electrochemical degradation of RDX were studied. Kinetics analysis shows that the electrochemical degradation of RDX follows the pseudo first-order reaction. The mechanism of electrochemical degradation of RDX was also discussed.

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