Superoxide chemistry. Convenient synthesis of dialkyl peroxides

Johnson, Roy A.; Nidy, Eldon G.

doi:10.1021/jo00899a049

Cited by 109 publications

(39 citation statements)

References 3 publications

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“…KO 2 , a commonly used carrier, has low solubility in DMSO (Merritt and Sawyer 1970, Sawyer et al 1983, Moorcroft et al 2003. Whereas crown ethers can be used to improve the solubility of KO 2 (Johnson and Nidy 1975, Valentine and Curtis 1975, Sawyer et al 1983, the more soluble quaternary ammonium superoxide Foote 1976, Sawyer et al 1983) is an alternative. In addition, the use of quaternary ammonium salts Brought to you by | University of California Authenticated Download Date | 1/5/15 6:04 AM is reported to increase not only the stability of the electrogenerated superoxide anion but also its nucleophilicity (Merritt andSawyer 1970, Moorcroft et al 2003).…”

Section: Pyrrmentioning

confidence: 99%

Deep oxidative desulfurization of liquid fuels

Mjalli

Ahmed

Al-Wahaibi

et al. 2014

Reviews in Chemical Engineering

166

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Increase in energy demand and consumption has been accompanied by a corresponding increase in sulfur emissions. These pollutants have both health and economic consequences. Furthermore, it significantly reduces the efficiency of advanced emission control systems of diesel engines, thereby indirectly causing more harm to the environment. This resulted in stringent sulfur emission limit down to about 15 ppm or less and in turn served as an incentive for research into alternative sulfur reduction technologies. Although feasible improvements to hydrodesulfurization are currently under investigation, adsorptive, extractive, oxidative and biodesulfurization have also been studied in recent years. Oxidative desulfurization appears to be one of the most promising desulfurization technologies due to its broadness and compatibility with other technologies such as extractive, adsorptive and biodesulfurization. The advent of ionic liquids as extraction solvents has made this even more so. This work, therefore, reviews the different approaches and investigations carried out on oxidative desulfurization while identifying research gaps and giving important recommendations.

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Section: Pyrrmentioning

confidence: 99%

Deep oxidative desulfurization of liquid fuels

Mjalli

Ahmed

Al-Wahaibi

et al. 2014

Reviews in Chemical Engineering

166

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“…HzO Zn(0,) + PtO -Pt(02) + ZnO Likewise, a similar process may occur between the electrode surface and the H202 that is produced via reactions 2 and 7 P t O + Hz02 -Pt(O2) + H2O (16) In the case of Mn(I1) ions, the presence of H202 from the proton induced disproportionation of 02-(reactions 2 or 7) can lead to the production of .OH radicals Mn" + H202 -Mn111(OH)2+ + .OH (17) *OH Pt + .OH -Pt(OH)* -PtO + H2O (18) Because the weakest solvation of 02-occurs in MeCN (of the solvents that have been considered in the present study), superoxide should exhibit its maximum reactivity in this solvent. The peak separations for the 02/02-cyclic voltammograms with metal electrodes strongly support this proposition ( Figure 5 and Table I).…”

Section: (15)mentioning

confidence: 99%

Effects of media and electrode materials on the electrochemical reduction of dioxygen

Sawyer¹,

Chiericato²,

Angelis³

et al. 1982

Anal. Chem.

389

326

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Cycllc voltammetry has been used to measure the extent of superoxlde Ion solvatlon (and consequent shift In the redox potentlal for the 02/02-couple) In acetonltrlle, dlmethylformamlde, pyridine, and dlmethyl sulfoxide. A parallel study of the reverslblllty of the 02/01 couple as a function of electrode materlal has been made for platinum, gold, mercury, and glassy carbon In acetonltrlle. The results Indicate that surface Interactions between superoxide Ion and metal-electrode surfaces occur. Additional studies of the reductlon of oxygenIn the presence of protic substrates and metal salts confirm that Lewis aclds promote the disproportkmatlon of superoxide Ion. I n the presence of electrophlles (e.g., CCI, and esters) the reduction current for dioxygen Is enhanced because of rapid nucleophlllc reactlons by 4-, which result In regeneration of 02.Although the electrochemical reduction of dioxygen to superoxide ion in aprotic solvents has been known since 1965 (1-5), the effects of media and electrode material have not been addressed in any systematic study. An early study (6) established that activated metal electrodes in aqueous media catalyze the reduction of O2 to water at a reduction potential characteristic of the particular metal. In contrast, at passivated metal electrodes the reduction of 02, which is independent of electrode material and pH, yields H202 via a one-electron mechanism with facile disproportionation of the 0,-intermediate (7). Three recent reviews discuss the redox chemistry and electrochemistry of dioxygen (8-10).The general view has been that the electrochemistry of O2 in aprotic media also is independent of media and electrode materials, and that only protic contaminants promote the rapid disproportionation of the 02-product to H202 and 0 2 . For a test of this conclusion the present study has been undertaken to compare the effects of various media and electrode materials on the reduction potential, reversibility, and overall electron stoichiometry for the cyclic voltammetry of dioxygen. EXPERIMENTAL SECTIONInstrumentation. The cyclic voltammetric measurements were made with either a Princeton Applied Research Model 173/ 175/179 potentiostat/universal programmer/electronic integrator or a universal potentiostat/amperostat that was constructed from operational amplifiers (11). The electrochemical cell (Brinkman) included (a) a platinum-foil auxiliary electrode that was isolated from the bulk solution by a glass tube with a medium frit, (b) a Ag/AgCl reference electrode in a glass tube closed with a cracked sofbglaas tip that contained aqueous Me4NCl (concentration was adjusted to obtain a potential of 0.000 V vs. SCE) (12), (c) a luggin capillary that contained the bulk electrolyte solution and the reference electrode (the capillary tip was placed within 1 mm of the working electrode surface), (c) inlet/outlet tubes for gas dispersion in the solution or over its surface, and (d) the working electrode. The latter was either a Beckman Model 39273 platinum-inlay electrode (area, 0.23 cm2) or on...

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“…Attempted mation of alkyl and acyl peroxides and hydro-isolation of 2 from solution led inevitably to peroxides using free superoxide with a1ky1 and violent explo.yions. The identity of 2 was inferred acyl halides, and sulphonate esters have been reported (4)(5)(6). It was further shown that super-X oxide is a moderately active nucleophile in displacement reactions of alkyl and electrophilic aryl halides (6-9).…”

Section: During the Past Decade There Has Been Goodmentioning

confidence: 99%

“…3b was purified by preparative tlc (benzene as eluant); nmr (CDCI,) 6 4.62 (2H, s), 4 Hydrolysis of 3a, b, c 3a, b, c (2 mmol) were dissolved in 10 ml EtOH 95%. Concentrated H2S04 (1 ml) was added and the mixture was refluxed for 1 h. The cooled solution was neutralized carefully with aqueous NaOH (2073, saturated with NaCI, and extracted with ether.…”

Section: O-lodomethylbenzenemethyl I-phthalanyl Ether 3bmentioning

confidence: 99%