The Oxidation of Phenothiazine and Related Compounds with Concentrated Sulfuric Acid

Tsujino, Youichi

doi:10.1246/nikkashi1948.90.8_809

Cited by 7 publications

(4 citation statements)

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“…As has already been mentioned, the phenothiazine cation radical under certain conditions may undergo dimerization leading to the formation of 3,1O1-diphenothiazinyl and a small amount of 1,lO'-diphenothiazinyl (2). In the present work, the formation of diphenothiazinyls was not detected.…”

Section: Resultssupporting

confidence: 48%

“…If V -[H+] at pH 1-3, it means that another proton transfer occurs before the electron transfers. This may be protonation of the anions of the oxidants: pK, values for HV03 and HCr, 0,-are 3.8 and 0.7, respectively (19), and hence the sequence is Since pH < (pK, -2), the role of equilibrium [2] is negligible and where KO,,+ is the equilibrium constant of process [3]. For potassium dichromate at pH > 2, K~,,+ >> [H'] and, approximately, [5] …”

Section: Resultsmentioning

confidence: 99%

“…Chemical (2)(3)(4)(5)(6) and electrochemical (7,8 ) oxidation of phenothiazine has been studied in acidic media. Oxidation of phenothiazine in concentrated sulphuric acid leads via cation radical states to 3,101-diphenothiazinyl and small quantities of 1,lO'-diphenothiazinyl (2).…”

Section: Introductionmentioning

confidence: 99%

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Chemical and electrochemical oxidation of phenothiazine

Pankratov¹,

Uchaeva²,

Stepanov³

1993

Can. J. Chem.

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ALEXEI N. PANKRATOV, INNA M. UCHAEVA, and ALEXANDER N. STEPANOV. Can. J. Chem. 71, 674 (1993) The oxidation of phenothiazine in dilute solutions of sulphuric acid leads to the corresponding cation radical. Using a potentiometric technique, a pK, value of 5.72 ? 0.05 was determined for phenothiazine. The kinetics has been studied and participation of both protonated and unprotonated oxidant in the oxidation reaction has been confirmed. Using a voltammetric technique with a rotating disk electrode, the anodic oxidation of phenothiazine was shown to be a oneelectron diffusion-controlled process. A quantum chemical explanation was found for the direction of phenothiazine protonation and the absence of a dimerization stage of oxidation.ALEXEI N. PANKRATOV, INNA M. UCHAEVA et ALEXANDER N. STEPANOV. Can. J . Chem. 71, 674 (1993) L'oxydation de la phknothiazine, en solutions dilukes d'acide sulfurique, conduit au cation radical. Faisant appel a une technique potentiomktrique, on a dttermink un pK, de 5,72 * 0,05 pour la phenothiazine. On a ktudi6 la cinttique de la reaction et on a dCmontr6 que l'oxydant proton6 aussi bien que le non proton6 participent a la r6action d'oxydation. Faisant appel a la technique de voltamp6romttrie avec une tlectrode a disque tournant, on a dCmontr6 que l'oxydation anodique est une rkaction impliquant un klectron dans un processus contr616 par la diffusion. On a expliquk la direction de la protonation de la phenothiazine et I'absence d'ktape de dimkrisation durant I'oxydation.[Traduit par la rkdaction]

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Section: Resultssupporting

confidence: 48%

Section: Resultsmentioning

confidence: 99%

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Chemical and electrochemical oxidation of phenothiazine

Pankratov¹,

Uchaeva²,

Stepanov³

1993

Can. J. Chem.

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“…4,4'-Tris-tert-octyl-diphenylamine, (TODPA), -17, impurity in DODPA from afkylation, 248 (4.07), 290nm (4 14),. (EI) m/z 505 (M+') (41%), 448 (5),434 (loo), 378(8), 362 (15), 322 (531, 250(13), 182 (23), 71 (51, 57 (62),6 7.40 ( l H , s, H-3), 7.17 (2H, AA'BB', J = 8.5 Hz, 3',5'-H), 7.12 (2H, m, 5, 6-H), 6.72 (2H, A A ' d , J = 8.5 Hz, 2',6'H), 5.25 br ( l H , s, NH), 1.86 (2H, s, 2-CH2), 1.73 (2H, s), 1.68 (2H, S) (4,4'-CH2), 1.46 (6H, S, C(CH&), 1.36 (6H, s), 1.35 (6H, S) (4,4'-C(CH3)2), 0.78 (9H, s), 0.75 (9H, S), 0.73 (9H, S) (C(CH3)3), 0.72 (9H, S ) (4,4'-C(CH3)3). (d) Unknown D: 1-(4',4''-Di-tert-octyldiphenylamino)-3,7-di-tert-octyl-phenoxazine, 6, ), 1630 (C=C(?…”

mentioning

confidence: 99%

Fate of amine antioxidants during thermal oxidative ageing of neopentylpolyl ester oils

Zeman¹,

Roenne²,

Trebert³

1987

J of Synthetic Lubrication

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The main products of the thermal‐oxidative degradation of p, p'‐di‐tert‐ octyldiphenylamine, phenothiazine and 3,7‐di‐tert‐octylphenothiazine (DODPA/PTZ/DOPTZ) in pentaerythritol ester at 200°C were isolated and identified. Recombination o f aminyl radicals giving various dehydrodimers and dehydro‐trimers is obviously the dominating reaction in the primary stage of antioxidant depletion during ageing of inhibited ester oils. Minor degradation products include quinone imines, quinones, sulphoxides, phenoxazine and phenoxazone derivatives. Because of the complexity of the reactions product analyses are inevitably incomplete.

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Free radicals of phenothiazine and related compounds. IV. Phenothiazinyl‐ and Diphenothiazine‐ Copper Complexes as intermediates and products in the interaction of phenothiazines with copper(II) halides

Diudea

Silberg

1982

J. Prakt. Chem.

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Freie Radikale des Phenothiazins und ähnliche Verbindungen. IV. Phenothiazinyl‐ und Diphenothiazin‐Kupferkomplexe als Zwischen‐ und Endprodukte in der Reaktion von Phenothiazin mit Kupfer (II)‐halogeniden Darstellung und Eigenschaften einiger Komplexverbindungen des 10‐Phenothiazinylradikals und deren Dimerisierungsprodukte mit Cu(I)‐ und Cu(II)‐ionen werden beschrieben. Ein Mechanismus für die selektive Chlorierung von Phenothiazinen in Position 1 mittels CuCl2 wird diskutiert. Die Möglichkeit ähnlicher Bromierungen mittels CuBr2 wird demonstriert.

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The Oxidation of Phenothiazine and Related Compounds with Concentrated Sulfuric Acid

Cited by 7 publications

References 0 publications

Chemical and electrochemical oxidation of phenothiazine

Chemical and electrochemical oxidation of phenothiazine

Fate of amine antioxidants during thermal oxidative ageing of neopentylpolyl ester oils

Free radicals of phenothiazine and related compounds. IV. Phenothiazinyl‐ and Diphenothiazine‐ Copper Complexes as intermediates and products in the interaction of phenothiazines with copper(II) halides

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