Peroxyacetic acid, oxidation

Azo and azoxy compounds are potential by-products of peroxyacetic acid oxidations, particularly when the rate of oxidation is slow. Competitive condensation reactions are usually avoided by using an excess of oxidant and also avoiding the presence of excess acid which retards amine oxidation. The latter is sometimes suppressed by using a sodium bicarbonate buffer.i i i ... 

In this study we have investigated selective oxidation as a potential organic sulfur characterization approach. In particular we have used the peroxyacetic acid oxidation procedure. Although this selective oxidant has received some attention in the study of lignin (24) and humic acid structures (25), its application to the study of coal has been limited to only a few instances (26.27J with very little information about organic sulfur species being reported. 

Peroxyacetic acid oxidation is similar to the peroxytrifluoroacetic acid (Deno) oxidation (28). These peroxide systems are reported to selectively oxidize the aromatic portions of molecules while leaving aliphatic portions intact (29). Peroxyacetic acid will oxidize aromatic units to phenolic units via hydroxylation. These phenolic moieties will oxidize rapidly to ortho and para quinones, the latter of which are unstable are undergo ring fission to form diene carboxylic acids (30). 

In addition each soluble oxidation product was examined by proton and carbon-13 NMR. Each spectra can be split up into three regions an aliphatic region, an aromatic region and a carbonyl region. If we compare the NMR spectra for a THF extract before and after oxidation we can see that the oxidized sample is much less aromatic than before oxidation. This would suggest that the peroxyacetic acid oxidation is similar to that of the peroxytrifluoroaectic acid or "Deno" oxidation (28 29) in which preferential preservation of aliphatic units is observed. 

CED [Conversion Extraction Desulfurization] A process for reducing the sulfur content of diesel fuel. Peroxyacetic acid oxidizes the organic sulfur compounds to sulfones, which are removed by solvent extraction. Developed in 2000 by Petro Star. 

Peroxyacetic acid oxidation of 2-acetoxymethyl-5-methylpyrazine gave the 1,4-dioxide which hydrolyzed in 0.1% sulfuric acid to 2-hydroxymethyl-5-methyl-pyrazine 1,4-dioxide (625) and 2,3-di(acetoxymethyl)pyrazine 1,4-dioxide was subjected to transesterification with lower alcohols in the presence of a catalytic amount of alkali to give 2,3-di(hydroxymethyl)pyrazine 1,4-dioxide (739). 

Whereas peroxyacetic acid oxidizes 2,6-dichloroaniline to 2,6-dichlo-ronitrosobenzene [/5J], peroxytrifluoroacetic acid carries the oxidation to the nitro compound. Refluxing 2,6-dichloroaniline with peroxytrifluoroacetic acid, which is prepared in situ from 90% hydrogen peroxide and trifluoroacetic anhydride in dichioromethane, gives 2,6-dichloronitroben-zene in 89-92% crude yields and 59-73% pure yields [290. 2-Amino-4-methylpyridine treated with 30% hydrogen peroxide in fuming sulfuric acid at 10-25 °C for 50 h yields 68% of 4-methyl-2-nitropyridine [203]. 

W Lawrence, RD McKelvey, and DC Johnson. The peroxyacetic acid oxidation of a lignin-related (3-aryl ether. Svensk. Papperstidn. 83 11-18, 1980. 

Whereas peroxyacetic acid oxidizes aromatic amines at room temperature to nitroso compounds, further oxidation to nitro compounds occurs in boiling chloroform.207 Trifluoroperoxyacetic acid208 and a mixture of maleic anhydride and hydrogen peroxide209 are valuable reagents for oxidizing aromatic amines in general to nitro compounds. 

Previous stereochemical analyses of the results of olefin epoxidation have demonstrated both steric and polar effects. However, several recent reports suggest that other factors should be considered. The peroxyacetic acid oxidation of A -tetrahydrobenzonitrile produced a high yield of the rra 5-epoxide (33) as expected. Peroxybenzoic acid epoxidation of methyl... 

Improvements both in reagents and techniques now permit the isolation of some highly strained and reactive epoxides. Evidence has been provided for the existence of the a-lactone (48) after peroxyacetic acid oxidation of the keten (47) under mild conditions. Although the epoxide (48) will subsequently... 

A computational study of the Baeyer-Villiger oxidation of benzaldehyde and acetaldehyde has been reported. Computational studies with peroxyacetic acid suggest that the first step is rate limiting and the addition of the peroxyacetic acid oxidation catalyst to the ketone carbonyl to produce the Criegee or tetrahedral intermediate (Scheme 163) "... 

Oxidation. Acetaldehyde is readily oxidised with oxygen or air to acetic acid, acetic anhydride, and peracetic acid (see Acetic acid and derivatives). The principal product depends on the reaction conditions. Acetic acid [64-19-7] may be produced commercially by the Hquid-phase oxidation of acetaldehyde at 65°C using cobalt or manganese acetate dissolved in acetic acid as a catalyst (34). Liquid-phase oxidation in the presence of mixed acetates of copper and cobalt yields acetic anhydride [108-24-7] (35). Peroxyacetic acid or a perester is beheved to be the precursor in both syntheses. There are two commercial processes for the production of peracetic acid [79-21 -0]. Low temperature oxidation of acetaldehyde in the presence of metal salts, ultraviolet irradiation, or osone yields acetaldehyde monoperacetate, which can be decomposed to peracetic acid and acetaldehyde (36). Peracetic acid can also be formed directiy by Hquid-phase oxidation at 5—50°C with a cobalt salt catalyst (37) (see Peroxides and peroxy compounds). Nitric acid oxidation of acetaldehyde yields glyoxal [107-22-2] (38,39). Oxidations of /)-xylene to terephthaHc acid [100-21-0] and of ethanol to acetic acid are activated by acetaldehyde (40,41). 

Acetaldehyde oxidation generates peroxyacetic acid which then reacts with more acetaldehyde to yield acetaldehyde monoperoxyacetate [7416-48-0], the Loesch ester (26). Subsequently, parallel reactions lead to formation of acetic acid and anhydride plus water. 

Electrolytic oxidation gives acetylene dicarboxyhc acid [142-45-0] (2-butynedioic acid) in good yields (49) chromic acid oxidation gives poor yields (50). Oxidation with peroxyacetic acid gives malonic acid [141-82-2] (qv) (51). 

Derivative Formation. Hydrogen peroxide is an important reagent in the manufacture of organic peroxides, including tert-huty hydroperoxide, benzoyl peroxide, peroxyacetic acid, esters such as tert-huty peroxyacetate, and ketone derivatives such as methyl ethyl ketone peroxide. These are used as polymerization catalysts, cross-linking agents, and oxidants (see Peroxides and peroxide compounds). 

The aromatic ring of a phenoxy anion is the site of electrophilic addition, eg, in methylolation with formaldehyde (qv). The phenoxy anion is highly reactive to many oxidants such as oxygen, hydrogen peroxide, ozone, and peroxyacetic acid. Many of the chemical modification reactions of lignin utilizing its aromatic and phenoHc nature have been reviewed elsewhere (53). 

Oxidation of perjliwro- 1,4-benzoquinone hy peroxyacetic acid gives comparatively good yields of 2,3-difluoromaleic acid [74] (equation 65). 

Destruction of the aromatic ring is the mam reaction in the oxidation of tetrafluoro-o phenyleiiediamine with lead tetraacetate by products are tetrafluorobenzotnazole and tetrafluorochinoxalme denvatives [92] (equation 85) Polyfluonnated benzylideneanilines are oxidized by peroxyacids to different products dependmg on reaction contitions at room temperature the benzylidene carbon is oxidized with the formation of peroxy bonds [93 94] (equation 86), whereas in refluxing agent, the azomethme bond is cleaved [93] (equation 86) Pentafluorobenzylidencanilme is oxidized by peroxyacetic acid in dichlo-romethane at room temperature to perfluorobenzoic acid in a 77% yield [93]... 

The reaction of 1,2,4-triazine 4-oxides 8 bearing substituents at the 3, 5, and 6 positions with peroxyacetic acid proceeds as an N-oxidation process exclusively at the 1 position, resulting in 1,2,4-triazine 1,4-dioxides 14. Oxidation of 1,2,4-triazine 4-oxides 8 unsubstituted at the 5 position leads to 5-hydroxy-1,2,4-triazine 4-oxides 15 (76LA153). 

Toxicity. The peroxy acid is highly toxic and may cause death or permanent injury after very short exposure to small quants (Ref 12) Uses. Peroxyacetic acid is the most important epoxidation reagent used today because of its economical availability and ease of use with a wide variety of reactants (Ref 10). It also finds wide usage as an organic oxidizing agent (Ref 11) Refs 1) Beil 2, 169, (78), [174] [379 ... 

The rate-determining step was, therefore considered to be reaction of bromine with peroxyacetic acid to give a species (suggested as bromine acetate)which subsequently and rapidly, brominates. Formation of bromine acetate was believed to take place according to the reaction scheme represented by equilibrium (158) (which is analogous to the mercuric oxide oxidation of bromine) followed by either equilibrium (159), (160) or (161), viz. 

In the synthesis of Travoprost, an antiglaucoma agent, a bicyclo[2.2.1]heptan-2-one is converted to a lactone.240 The commercial process uses peroxyacetic acid as the oxidant and gives a 40% yield. The regioselectivity in this case is only 3 1 but the unwanted isomer can be removed by selective hydrolysis. 

Admixture causes explosion, owing either to direct oxidation of acetic acid by the highly concentrated hydrogen peroxide produced, or perhaps to formation of concentrated peroxyacetic acid. 

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