Kinetics of the oxidation of diphenyl sulfide with hydrogen peroxide catalyzed by sodium metavanadate

1982 ◽  
Vol 60 (7) ◽  
pp. 848-852 ◽  
Author(s):  
Yoshiro Ogata ◽  
Kazushige Tanaka
Keyword(s):  
Hydrogen Peroxide ◽  
Rate Constant ◽  
Reaction Rate ◽  
Catalytic Amount ◽  
Probable Mechanism ◽  
Initial Concentration ◽  
Sodium Metavanadate ◽  
Low Concentration ◽  
Diphenyl Sulfide ◽  
Kinetics Of

The oxidation of diphenyl sulfide (Ph2S) by hydrogen peroxide in the presence of a catalytic amount of sodium metavanadate (NaVO3) has been studied kinetically by means of iodometry of hydrogen peroxide. The reaction rate is expressed as: v = k[NaVO3]st[Ph2S]2, when the concentration of catalyst is very low and [Ph2S]0/[H2O2]0 > 2, where []st and []0 mean stoichiometric and initial concentration, respectively. The effective oxidant may consist of polymeric as well as monomeric peroxyvanadate in view of the effect of concentration of catalyst on the rate. The main oxidizing species at low concentration of catalyst seems to be diperoxyvanadate VO5−. The rate constant k2 in v = k2[Ph2S]2 tends to decrease with initial concentration of H2O2, which is present in excess of the catalyst. A probable mechanism for the oxidation is discussed.

Kinetics of the oxidation of dimethyl sulfoxide with aqueous hydrogen peroxide catalyzed by sodium tungstate

1981 ◽  
Vol 59 (4) ◽  
pp. 718-722 ◽  
Author(s):  
Yoshiro Ogata ◽  
Kazushige Tanaka
Keyword(s):  
Hydrogen Peroxide ◽  
Dimethyl Sulfoxide ◽  
Sodium Tungstate ◽  
Catalytic Amount ◽  
Active Oxygen ◽  
Probable Mechanism ◽  
Polarographic Study ◽  
Aqueous Hydrogen Peroxide ◽  
First Order ◽  
Kinetics Of

The oxidation of dimethyl sulfoxide (DMSO) by hydrogen peroxide in the presence of a catalytic amount of sodium tungstate (Na2WO4) has been studied kinetically by means of iodometry of hydrogen peroxide. The reaction is first-order with respect to the substrate and the catalyst, but independent of the concentration of hydrogen peroxide which is present in excess of the catalyst. The polarographic study implies that in solutions two main kinds of peroxytungstic acids (H2WO5 and H2WO8) are formed which contain active oxygen in ratios (active oxygen):(Na2WO4) of 1:1 and 4:1, respectively. The effect of acidity on the oxidation rate and a probable mechanism involving a rate-determining attack of peroxytungstic acids are discussed.

scholarly journals Analysis of the Kinetics of Swimming Pool Water Reaction in Analytical Device Reproducing Its Circulation on a Small Scale

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4820 ◽  
Author(s):  
Wojciech Kaczmarek ◽  
Jarosław Panasiuk ◽  
Szymon Borys ◽  
Aneta Pobudkowska ◽  
Mikołaj Majsterek
Keyword(s):  
Activation Energy ◽  
Water Quality ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Small Scale ◽  
Pool Water ◽  
Swimming Pool Water ◽  
Kinetics Of ◽  
Analytical Device

The most common cause of diseases in swimming pools is the lack of sanitary control of water quality; water may contain microbiological and chemical contaminants. Among the people most at risk of infection are children, pregnant women, and immunocompromised people. The origin of the problem is a need to develop a system that can predict the formation of chlorine water disinfection by-products, such as trihalomethanes (THMs). THMs are volatile organic compounds from the group of alkyl halides, carcinogenic, mutagenic, teratogenic, and bioaccumulating. Long-term exposure, even to low concentrations of THM in water and air, may result in damage to the liver, kidneys, thyroid gland, or nervous system. This article focuses on analysis of the kinetics of swimming pool water reaction in analytical device reproducing its circulation on a small scale. The designed and constructed analytical device is based on the SIMATIC S7-1200 PLC driver of SIEMENS Company. The HMI KPT panel of SIEMENS Company enables monitoring the process and control individual elements of device. Value of the reaction rate constant of free chlorine decomposition gives us qualitative information about water quality, it is also strictly connected to the kinetics of the reaction. Based on the experiment results, the value of reaction rate constant was determined as a linear change of the natural logarithm of free chlorine concentration over time. The experimental value of activation energy based on the directional coefficient is equal to 76.0 [kJ×mol−1]. These results indicate that changing water temperature does not cause any changes in the reaction rate, while it still affects the value of the reaction rate constant. Using the analytical device, it is possible to constantly monitor the values of reaction rate constant and activation energy, which can be used to develop a new way to assess pool water quality.

Influence of Natural Organic Matter on Oxidation of Volatile Organic Compounds by the H2O2/VisUV Process

1997 ◽  
Vol 2 (3) ◽  
Author(s):  
James M. Symons ◽  
Charlene M. Baker ◽  
H. William Prengle
Keyword(s):  
Hydrogen Peroxide ◽  
Rate Constant ◽  
Reaction Rate ◽  
Tap Water ◽  
Reaction Rate Constant ◽  
Photon Flux ◽  
Excess Hydrogen ◽  
Volatile Organic ◽  
Natural Organic Material ◽  
Experimental Runs

AbstractThis paper presents experimental research to determine the affect of background natural organic material (NOM) on the conversion of five (5) VOC's: 1,1,1-trichloroethane (TCA), benzene (BNZ), trichloroethylene (TCE), 1,4-dichlorobenzene (DCB), and tetrachloroethylene (PCE). Experiments were conducted using DI water and Houston tap water ([TOC] = 3.6 mg/L) as solvents. In addition, the affects of buffer form and excess hydrogen peroxide were determined. Experimental runs were conducted in a photochemical-flow-stirred-tank reactor (pcfSTR), using a 450 W visible/ultraviolet radiation source. The data were analyzed using the Prengle- Shimoda reaction rate model, yielding the reaction rate constant ka (μmols A conv/min, Lr, photon flux) for comparison purposes. Analysis of the experimental data indicated the following conclusions: 1) At the concentrations used for bicarbonate or phosphate buffer, little or no affect was observed; 2) The presence of NOM surpressed the reaction rate for three of the compounds, TCA, BNZ, and PCE at the 95 % confidence level; and 3) Excess hydrogen peroxide, beyond the stoichiometric value, increased the reaction rate constant for all five compounds. The greatest increase was seen for DCB.

Kinetics and mechanism of oxidation of iodide ion by the molybdenum (VI) – hydrogen peroxide system

1990 ◽  
Vol 68 (9) ◽  
pp. 1499-1503 ◽  
Author(s):  
Conchita Arias ◽  
Fernando Mata ◽  
Joaquin F. Perez-Benito
Keyword(s):  
Hydrogen Peroxide ◽  
Rate Constants ◽  
Reaction Rate ◽  
Sodium Molybdate ◽  
Initial Reaction Rate ◽  
Initial Reaction ◽  
Kinetics Of Oxidation ◽  
Iodide Ion ◽  
Aqueous Perchloric Acid ◽  
Kinetics Of

The kinetics of oxidation of potassium iodide by hydrogen peroxide in aqueous perchloric acid has been studied both in the absence and in the presence of sodium molybdate by means of the initial-rates method. The law found for the total initial reaction rate is[Formula: see text]The activation energies associated with rate constants k1, k2, and k3 are 52 ± 1, 49 ± 1, and 42 ± 3 kJ mol−1, respectively. A mechanism in agreement with the experimental kinetic data is proposed, according to which rate constants k1, k2, and k3 correspond to the oxidations of iodide ion by H2O2, H3O2+ and H2MoO5, respectively. Keywords: catalysis, hydrogen peroxide, iodide ion, kinetics, molybdate ion.

scholarly journals Study on Kinetics of GD Hydrolysis in HCl aqueous

2021 ◽  
Vol 267 ◽  
pp. 02060
Author(s):  
Shaoxiong Wu ◽  
Hongpeng Zhang ◽  
Ting Miao ◽  
Haiyan Zhu ◽  
Lianyuan Wang ◽  
...  
Keyword(s):  
Rate Constant ◽  
Ph Value ◽  
Negative Ion ◽  
Hydrolysis Rate ◽  
Obvious Effect ◽  
Factors Affecting ◽  
Initial Concentration ◽  
First Order Kinetics ◽  
Kinetics Of ◽  
Positive Ion

Organophosphate neurotoxic agents like Sarin (GB) and Soman (GD) are lethal to person. Except various kinds of decontaminants, they can be also decomposed in natural environment through nucleophilic reaction, where acidic or alkaline substance was to accelerate their hydrolysis. Most of the papers were about GB hydrolysis. Information on GD hydrolysis was relatively small, especially about kinetics of GD in acidic solution. In view of possible effect of positive ion and negative ion on hydrolysis reaction, a relatively simple composes solution, HCl aqueous solutions, was selected to investigate the factors affecting GD hydrolysis rate. Results showed that GD hydrolysis was accorded with the first-order kinetics equation if pH value was kept constant. Its rate constant was independent of GD initial concentration when the amount of H+ was excess than its requested amount. The apparent hydrolysis rate constant (kobs) in pH of 0.90 was about 0.202 min-1 at 20°C, no matter what initial concentration of GD was. The concentration of H+ was the most important factor affecting its rate. The rate constant (kobs) in HCl aqueous as a function of pH value (0.90~2.80) obeyed an equation in 25°C, that is kobs =0.17×10-0.82×pH. Reaction temperature had an obvious effect on hydrolysis rate of GD. Every 10°C increase in temperature, kobs of GD hydrolysis was improved about 2.5 times. The activation energy value (Ea) of GD hydrolysis in HCl aqueous with a pH value of 0.90 was approximately 64.25 kJ/mol.

scholarly journals REACTION KINETICS OF Cu ELECTRO-DEPOSITION ON THE SURFACE OF TiO2/GRAPHITE

2015 ◽  
Vol 8 (2) ◽  
pp. 116
Author(s):  
Fitria Rahmawati ◽  
Wanodya Anggit Mawasthi ◽  
Patiha
Keyword(s):  
Equilibrium Constant ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Order ◽  
Electrode Reaction ◽  
Deposition Process ◽  
Anodic Reaction ◽  
Electro Deposition ◽  
First Order ◽  
Kinetics Of

Research on the kinetics of electrode reaction during copper electro-deposition on the surface of TiO2/graphite has been conducted. The aims of this research are to determine the ratio of anodic reaction rate to cathodic reaction rate , the ratio of anodic rate constant to cathodic rate constant , the equilibrium constant when the reaction reach equilibrium condition and to study the polarization in the electro-deposition reaction. Copper was deposited electrochemically from CuSO4 solution at various concentration i.e. 0.1 M; 0.2 M; 0.3 M; 0.4 M; 0.5 M. In every 5 minutes during electro-deposition process, the pH changes in anode cell was recorded and the change of Cu2+ concentration was also analyzed by spectrophotometric method. The result shows that the reaction order of Cu2+ reduction is first order and the oxidation of H2O in anodic cell is zero order. The ratio of anodic rate constant to cathodic rate constant, is 4.589´10-3 ± 0.071´10‑3. It indicates that the reaction rate  in cathode is larger than the reaction rate in anode and it allowed polarization.  The electrochemical cell reached equilibrium after 25 minutes with the equilibrium constant is 8.188´10-10 ± 1.628´10-10.

Electrochemistry of Titanium Tetrachloride in 1-Butyl-2,3-dimethyl Imidazolium Tetrafluoroborate

2007 ◽  
Vol 62 (9) ◽  
pp. 529-539 ◽  
Author(s):  
Yuriy Andriyko ◽  
Ulrike Fastner ◽  
Hermann Kronberger ◽  
Gerhard E. Nauer
Keyword(s):  
Cyclic Voltammetry ◽  
Diffusion Coefficient ◽  
Rate Constant ◽  
Relative Stability ◽  
Titanium Tetrachloride ◽  
Reduction Process ◽  
Disproportionation Reaction ◽  
Low Concentration ◽  
Stepwise Reduction ◽  
Kinetics Of

The electrochemistry of titanium tetrachloride has been examined in trialkyl-substituted imidazolium tetrafluoroborate at 65 °C. Ti(IV) reduction was studied with chronopotentiometry and cyclic voltammetry in melts with different concentrations of TiCl4. The diffusion coefficient of Ti(IV) ranged between 1.1·10−7 and 7·10−8 cm2 s−1. The electroreduction of Ti(IV) was found to proceed via the sequence of one-electron steps, the relative stability of the low valence intermediates being dependent on the concentration of TiCl4 in the electrolyte. The kinetics of an overlapping disproportionation reaction of Ti(II) was examined and its rate constant at low concentration (0.025 mol/l) of TiCl- was found to be k = 2 · 106 cm3 mol−1 s−1, Ti(0) being the final product of the stepwise reduction process at higher concentrations (0.03 - 0.14 mol/l).

Photocatalytic Degradation of Bisphenol AF in TiO2 Suspension

2014 ◽  
Vol 955-959 ◽  
pp. 2334-2339
Author(s):  
Pin Wen Wang
Keyword(s):  
Photocatalytic Degradation ◽  
Reaction Rate ◽  
Degradation Kinetics ◽  
Fluoride Concentration ◽  
Reaction Rate Constant ◽  
Rate Model ◽  
Initial Concentration ◽  
Fluoride Pollution ◽  
Kinetics Of ◽  
Bisphenol Af

The photodegradation behavior of bisphenol AF (BPAF) in TiO2 suspension was investigated. The influence of dissolved oxygen, TiO2 dosage, fluoride, and initial BPAF concentration on the degradation of BPAF was studied and described in details. The main purposes were to clarify the degradation kinetics of BPAF and quantify the fluoride concentration during the degradation. At an initial concentration of 40 mol/L, more than 97% of TOC was removed efficiency was achieved within 540 min irradiation, and the concentration of fluoride was 0.98 mg/L. Degradation of BPAF followed the Langmuir–Hinshelwood kinetics rate model and the reaction rate constant kre was 1.21 μM/min. The results obtained indicated that TiO2 photocatalytic degradation is a highly effective way to remove BPAF without any generation of more toxic products or fluoride pollution.

Crystallization Kinetics of CaOx in Artificial Urine and in Saline System

2014 ◽  
Vol 881-883 ◽  
pp. 708-711
Author(s):  
Lan Qing Deng ◽  
Jun Fa Xue ◽  
Li Kuan ◽  
Jian Ming Ouyang
Keyword(s):  
Reaction Time ◽  
Calcium Oxalate ◽  
Crystallization Kinetics ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Order ◽  
Reaction Rate Constant ◽  
Artificial Urine ◽  
Kinetics Of

The crystallization kinetics of calcium oxalate (CaOx) was comparatively studied by detecting the change of free Ca2+ ions concentration with the reaction time in artificial urine and in saline system. The dynamics equations of CaOx crystallization was r=kcα, and the average reaction order (α) was 3.3 regardless of the relative suprasaturation degree (RS) of CaOx in the range of RS=10.58~17.53. The average reaction rate constant (κ) was (0.97±0.1)×109 in artificial urine and κ=(3.1±1.8)×109 in saline system, due to the presence of inhibitors to CaOx crystallization in artificial urine.

scholarly journals The Effect of Ingredients Mixing Sequence in Rubber Compounding upon Vulcanization Kinetics of Natural Rubber: An Autocatalytic Model Study

2018 ◽  
Vol 18 (4) ◽  
pp. 709
Author(s):  
Abu Hasan ◽  
Rochmadi Rochmadi ◽  
Hary Sulistyo ◽  
Suharto Honggokusumo
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Model ◽  
Reaction Rate Constant ◽  
Model Study ◽  
Vulcanization Kinetics ◽  
Kinetics Of ◽  
Mixing Sequence

This study examined the effect of ingredients mixing sequence to the vulcanization kinetics of natural rubber. The effects of mixing temperature, vulcanization temperature, and the carbon black type upon the kinetics were also studied by using rheography and an autocatalysis reaction model approach. The results showed that this model is good in providing information on vulcanization reaction kinetics of natural rubber. High vulcanization temperature resulted in high reaction rate constant. The more black carbon mixed at the beginning of the rubber mixing process, the higher reaction rate constant would be. The mixing of carbon black and rubber chemicals mixed into the rubber subsequently resulted in the higher reaction rate constant compared with that of simultaneously.

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