Dimethyldioxirane: Mechanism of benzaldehyde oxidation

“…The Bayer-Villiger oxidation of aromatic alde hydes with peracetic acid [40], ra-chloroperbenzoic acid [41,4 2], dimethyldioxirane [43] or hydrogen peroxide in the presence of selenium compounds [44], or (oxo-diperoxo-tungsten)phosphates [45], yields aryl formates which can be hydrolyzed easily giving phenols. So the purpose of this reaction se quence was usually the preparation of phenols from aromatic aldehydes.…”

Section: Phenol Has Also Been Converted To Phenyl Formate By the Actimentioning

confidence: 99%

Orthoamides, LVI [1]. A New Method of Wide Scope for the Preparation of Aryl Formates

Ziegler

Kantlehner

2001

Zeitschrift Für Naturforschung B

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Aryl Formates, Formylation, HydroxyarenesAryl formates 4a-u, 6 , 8 , 10, 12, 14, 16, 18, 20, 22, 24, 26 are prepared by formylation of hydroxyarenes 3a-u, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25 with /V,Af-diformylacetamide (1) or triformamide (2), respectively, in fairly good yields. The reactions can be catalyzed by sodium diformamide or praseodymium(III) triflate. The thiolformate 28 was obtained analogously from 1-thionaphthol (27).

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“…Can For personal use only. DMD stability (in a nonaqueous medium) Isolated solutions of DMD can be k e~t for months at -20°C (10); however, at room temperature they decompose comparatively quickly with reported lifetimes ranging from a few hours (1 1) to 24 h (12). While it has been reported that DMD decomposition follows a complex rate law (1 1, 12), Singh and Murray (10) have shown that first-order kinetics can be obtained at low DMD concentrations (0.03 M).…”

Section: Bleaching Of Kraft Pulp By In Situ Generation Of Dmdmentioning

confidence: 99%

Kraft pulp bleaching using dimethyldioxirane: stability of the oxidants

Bouchard¹,

Maine²,

Berry³

et al. 1996

Can. J. Chem.

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Dimethyldioxirane (DMD) is a cyclic peroxide made by oxidizing acetone with peroxymonosulfate (PMS) in water buffered at pH 7.5 using sodium bicarbonate. It has been shown that DMD generation can be achieved in situ within a pulp suspension allowing very selective TCF bleaching of kraft pulp. This process involves simultaneous generation of DMD, reaction of PMS and DMD with residual lignin, and spontaneous decomposition of both oxidants. The first part of this work is a kinetics study of the decomposition of PMS and DMD as a function of pH under conditions similar to those for in situ bleaching. The effect of chelation as well as the effect of transition metal ions on decomposition rate was also investigated. DMD is very sensitive to pH and its half-life is very short under alkaline conditions. The presence of any transition metal ion that can be involved in a one-electron transfer is detrimental to DMD stability. However, fast reaction of DMD with pulp almost counteracts the effect of metal ions.Key rvorrls: bleaching, peroxyn~onosulphate, dimethyldioxirane, metal ions, kinetics, decomposition, kraft pulp.RCsumC : Le dimkthyldioxirane (DMD) est un peroxyde cyclique obtenu par oxydation de l'acktone avec le peroxymonosulfate (PMS) en milieu aqueux tamponnC i pH 7,5 i I'aide du bicarbonate de sodium. La synthkse du DMD, lorsque rCalisCe in situ dans une suspension de pate kraft, reprCsente un procCdC de blanchiment sans chlore trks selectif. Au cours de ce prockdC, la synthkse du DMD, l'attaque de la lignine rksiduelle par le DMD et le PMS ainsi que la dCcomposition naturelle de ces deux oxydants se produisent simultanCrnent. Le premikre pnrtie de ce travail consiste en une ttude cinitique de la dCcoinposition du DMD et du PMS en fonction du pH dans des conditions similaires i celle du procCdC de blanchiment in situ. L'effet de la chelation ainsi que la prCsence d'ions mCtalliques ont Cgalement CtC CtudiCs. La dCcomposition du DMD est trks sensible au pH et des demi-vies trks courtes sont observtes en milieu basique. La prCsence de mCtaux de transition pouvant Cchanger un Clectron s'avkre ntfaste j. la stabilitk du DMD mais la vitesse de rkaction du DMD diminue grandement cet effet ntgatif.

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Dimethyldioxirane: Mechanism of benzaldehyde oxidation

Cited by 60 publications

References 16 publications

Kinetics of thermal decomposition of dimethyldioxirane in oxygen atmosphere

Kinetics of thermal decomposition of dimethyldioxirane in oxygen atmosphere

Orthoamides, LVI [1]. A New Method of Wide Scope for the Preparation of Aryl Formates

Kraft pulp bleaching using dimethyldioxirane: stability of the oxidants

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