Kinetics and mechanism of the reactions of the superoxide ion in solutions. II. The kinetics of protonation of the superoxide ion by water and ethanol

Afanas’ev, Igor B.; Kuprianova, N. S.

doi:10.1002/kin.550151009

Cited by 13 publications

(13 citation statements)

References 10 publications

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“…Therefore, the different solvations of O 2 •– and H 2 O in AcN, DMSO, and DMF can reasonably elucidate the solvent dependence of the O 2 •– protonation rate: AcN > DMF > DMSO. This is in accordance with the results of a previous study that proposed O 2 •– protonation by H 2 O or ethanol in AcN and DMF.…”

Section: Reactions and Potential Applications Of The Superoxide Ionsupporting

confidence: 93%

Superoxide Ion: Generation and Chemical Implications

Hayyan¹,

Hashim²,

AlNashef³

2016

Chem. Rev.

1,635

1,058

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Superoxide ion (O2(•-)) is of great significance as a radical species implicated in diverse chemical and biological systems. However, the chemistry knowledge of O2(•-) is rather scarce. In addition, numerous studies on O2(•-) were conducted within the latter half of the 20th century. Therefore, the current advancement in technology and instrumentation will certainly provide better insights into mechanisms and products of O2(•-) reactions and thus will result in new findings. This review emphasizes the state-of-the-art research on O2(•-) so as to enable researchers to venture into future research. It comprises the main characteristics of O2(•-) followed by generation methods. The reaction types of O2(•-) are reviewed, and its potential applications including the destruction of hazardous chemicals, synthesis of organic compounds, and many other applications are highlighted. The O2(•-) environmental chemistry is also discussed. The detection methods of O2(•-) are categorized and elaborated. Special attention is given to the feasibility of using ionic liquids as media for O2(•-), addressing the latest progress of generation and applications. The effect of electrodes on the O2(•-) electrochemical generation is reviewed. Finally, some remarks and future perspectives are concluded.

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Section: Reactions and Potential Applications Of The Superoxide Ionsupporting

confidence: 93%

Superoxide Ion: Generation and Chemical Implications

Hayyan¹,

Hashim²,

AlNashef³

2016

Chem. Rev.

1,635

1,058

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“…The correct calculation yields k 38 = 1.44×10 −1 L mol −1 s −1 at 21 °C and 1.94×10 −2 L mol −1 s −1 at 4 °C. Although never measured in water, the rate constant k 38 has been measured in dimethyl formamide and in acetonitrile for solutions which contained up to 0.6 mol L −1 H 2 O [ 13 , 14 ]. The values reported for k 38 in these solvents ranged from 0.5×10 −3 L mol −1 s −1 to 3.5×10 −3 L mol −1 s −1 with an indication in one report [ 14 ] that the value might increase with increase in water concentration.…”

Section: Resultsmentioning

confidence: 99%

Water calorimetry: A correction to the heat defect calculations

Klassen¹,

Ross²

2002

J. Res. Natl. Inst. Stand. Technol.

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In a recent publication, we used a reaction model (model III) to calculate the heat defect for the irradiation of aqueous solutions with ionizing radiation at 21 °C. Subsequent work has revealed that the literature value used for one of the rate constants in the model was incorrect. A revised model (model IIIR) incorporates the correct rate constant for 21 °C. Versions of models III and IIIR were created for irradiations at 4 °C. For our current water calorimetry protocol, the values of the heat defect for H2/O2-water (water saturated with a flow of 43 % H2 and 57 % O2, by volume) at 21 °C predicted by model III and model IIIR are similar but the value for 4 °C predicted by III is 30 % smaller than the value predicted by IIIR. Model IIIR predicts that the values of the heat defect at 21 °C and 4 °C lie within the range −0.023±0.002, in agreement with the values obtained from our water calorimetry measurements done using pure water and H2-saturated water at 21 °C and 4 °C. The yields of hydrogen peroxide in H2/O2-water at 21 °C and 4 °C were measured and agree with the predictions of model IIIR. Our water calorimetry measurements made with pure water and H2-saturated water are now of sufficient quality that they can be used to determine the heat defect for H2/O2-water better than can be done by simulations. However, consistency between the three systems continues to be an excellent check on water purity which is crucial, especially for the pure water system.

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“…We speculate that the electrochemical reduction of O 2 to O 2 ˙ − is followed by a chemical protonation step to generate other ROS such as a hydroperoxyl radical (HO 2 ˙), 43 which is susceptible to heterolytic and homolytic cleavages and eventually converges on H 2 O 2 . 44–46 Whether the conversion of HO 2 ˙ to H 2 O 2 proceeds electrochemically or chemically should be dependent on the proton donor concentration in solution and the reduction potential applied. 46 Once the hydroperoxide species is formed, CH 3 OH formation proceeds from its reaction with Rh III –CH 3 .…”

Section: Resultsmentioning

confidence: 99%