Acetyl peroxy

Acetyl peroxy nitrate, stmcture, 103, 104 Acetylsaturejol, triplet oxygen cycloaddition, 202, 204... 

Stockwell, W. R., J. B. Milford, D. F. Gao, and Y. J. Yang, The Effect of Acetyl Peroxy-Peroxy Radical Reactions on Peroxy-acetyl Nitrate and Ozone Concentrations, Atmos. Enriron., 29, 1591-1599(1995). 

For recent work on the liquid phase bimolecular acetyl peroxy-radical termination see refs. 81 and 83. 

Stockwell, W.R., J.B. Milford, D. Gao and Y.J. Yang The effect of acetyl peroxy-peroxy radical reactions on peroxyacetyl nitrate and ozone concentrations, Atmos. Environ. 29 (1995) 1591-1599. 

Acetaldehyde reacts with the OH radical to form CH3CO, which reacts further with O2 forming the acetyl peroxy radical ... 

This acetyl peroxy radical can then react with NO or NO2 (236) ... 

Acetyl peroxy radicals resulting from the addition of oxygen to CH3C O react further with NO ... 

The reaction with NO leads to the formation of CO2 and a methyl radical that is oxidized to formaldehyde by reactions (16)-(20). In addition, the oxidation of CH3 regenerates HO c so that the oxidation cycle continues. Association with NO2 produces peroxyacetyl nitrate (PAN). Its lifetime is longer than that of alkylperoxy nitrates, but strongly temperature dependent, ranging from 1 hr at 298 K to 140 d at 250 K. Thus, PAN can be transported over a great distance before undergoing thermal decomposition. Under conditions of lowNOj concentrations acetyl peroxy radicals interact also with HO2 radicals... 

Hasson AS, Tyndall GS, Orlando JJ (2004) A product yield study of the reaction of HO2 radicals with ethyl peroxy (C2H5O2), acetyl peroxy (CH3C(0)02), and acetonyl peroxy (CH3C(0)CH202) radicals. J Phys Chem A 108 5979-5989... 

Particularly under the low concentration of NO, several reactions of peroxy radicals that may produce excessive OH has been proposed. Dillon and Crowley (2008) reported that in the reaction of HO2 and peroxy radicals with carbonyl group, e.g. acetyl peroxy radical. 

An important reaction of the acylperoxy radical is with NO2 to form an acylperoxy nitrate. In the example shown, the oxidation of acetaldehyde gives acetyl peroxy radicals which can react with NO2 to form peroxyacetyl nitrate, CH3C(0)02N02, generally known as PAN ... 

All evidence points to effectively exclusive abstraction of the aldehydic H by NO3 and Cl, as well as OH. The acetyl radical so formed reacts rapidly with O2 to form the acetyl peroxy radical, which in turn gives peroxyacetylnitrate (PAN) on reaction with NO2 and CH3 (and hence CH3O2 under atmospheric conditions) on reaction with NO ... 

Nitrates Peroxy acetyl nitrate Photochemical — 0-100 ppbv... 

Treatment of 51 with an excess of sodium benzoate in DMF resulted in substitution and elimination, to yield the cyclohexene derivative (228, 36%). The yield was low, but 228 was later shown to be a useful compound for synthesis of carba-oligosaccharides. <9-Deacylation of228 and successive benzylidenation and acetylation gave the alkene 229, which was oxidized with a peroxy acid to give a single epoxide (230) in 60% yield. Treatment of 230 with sodium azide and ammonium chloride in aqueous 2-methoxyeth-anol gave the azide (231,55%) as the major product this was converted into a hydroxyvalidamine derivative in the usual manner. On the other hand, an elimination reaction of the methanesulfonate of 231 with DBU in toluene gave the protected precursor (232, 87%) of 203. 

DL-Valiolamine (205) was synthesized from the exo-alkene (247) derived from 51 with silver fluoride in pyridine. Compound 247 was treated with a peroxy acid, to give a single spiro epoxide (248, 89%) which was cleaved by way of anchimeric reaction in the presence of acetate ion to give, after acetylation, the tetraacetate 249. The bromo group was directly displaced with azide ion, the product was hydrogenated, and the amine acety-lated, to give the penta-A, 0-acetyl derivative (250,50%). On the other hand. 

Attention has been given to possible adverse effects of incorporating tert-butyl methyl ether into antomobile fuels. tert-Butyl formate is an established product of photolysis, and it has been shown that photolysis in the presence of NO can produce the relatively stable tert-butoxyformyl peroxynitrate. This has a stability comparable to that of peroxy-acetyl nitrate, and may therefore increase the potential for disseminating NO (Kirchner et al. 1997). 

The same is true for peroxides and peroxy acids so performic and peracetic acids or acetyl peroxide are particularly dangerous, whereas perstearic acid (eighteen carbon atoms) is perfectly stable. 

N-nitrosothiazolidine-4-carboxylie acid N-nitrosothiazolidine polynuclear aromatic hydrocarbons polynuclear aromatic compounds peroxy acetyl nitrate... 

The member of this series most commonly found in the atmosphere is peroxy-acetyl nitrate (PAN)... 

Two examples serve to illustrate these photochemical relationships. One member of the family of atmospheric peroxy radicals is the peroxy acetyl radical, CH3C(0)02. In at least the warm portion of the troposphere, PAN is near thermal equilibrium with the peroxy acetyl radical and NO . The equilibrium constant for this reaction has been measured in laboratory studies. Therefore, if concentrations of both PAN and N02 are measured, the concentration of these radicals can be calculated from the equilibrium constant and the ratio of the two nitrogen species as shown in Figure 2. The... 

Figure 2. Peroxy acetyl radical equilibrium chemistry and concentrations derived for a 4-day period during afield study in rural Pennsylvania. The two curves give model predicted concentrations for two different scenarios. (Adapted with permission from reference 8. Copyright 1991 American Geophysical Union.)...

The fate of the organic nitrate peroxy radical produced in reaction 14 is probably oxidation of NO to N02 and then decomposition, yielding acetyl nitrate, formaldehyde, and a hydroperoxy radical as shown in reactions 15 and 16. 

The further decomposition of acetyl nitrate in the atmosphere has not been studied. The oxidation of isoprene by the hydroxyl radical proceeds via repeated steps of OH addition across the double bond, followed by addition of 02 to form a peroxy radical. The peroxy radical then either oxidizes NO to N02 or adds NO to form an organic nitrate. The alkoxy radical produced in the former step underwent decomposition to form both stable and reactive products. A number of possible pathways exist for forming presumably stable organic nitrates (bold in reactions 7 through 16). 

Perhydroxyl radical, 75 thermal generation from PNA of, 75 Peroxy radical generation, 75 Peroxide crystal photoinitiated reactions, 310 acetyl benzoyl peroxide (ABP), 311 radical pairs in, 311, 313 stress generated in, 313 diundecanyl peroxide (UP), 313 derivatives of, 317 EPR reaction scheme for, 313 IR reaction scheme for, 316 zero field splitting of, 313 Peorxyacetyl nitrate (PAN), 71, 96 CH3C(0)00 radical from, 96 ethane oxidation formation of, 96 IR spectroscopy detection of, 71, 96 perhydroxyl radical formation of, 96 synthesis of, 97 Peroxyalkyl nitrates, 83 IR absorption spectra of, 83 preparation of, 85 Peroxymethyl reactions, 82 Photochemical mechanisms in crystals, 283 atomic trajectories in, 283 Beer s law and, 294 bimolecular processes in, 291 concepts of, 283... 

The addition of the peroxyl radical to the double bond is governed by the electron density in the alkene bond and by electrophility of the radical. The rate constants of addition reactions increase with an increase of electron density on the double bond and with the increase of the electrophilic character of a radical (Table 6). The considerably larger electrophility of acyl peroxy radical (CH3CO3, C6H5CC>3) may explain by 5 orders faster addition of acyl peroxyl radicals [69] to a-methyl styrene at 20 °C. Electrophility of radicals leads to the marked reduction of activation energy of addition to alkenes methyl peroxyl radical has 47 kJ/mol, while acetyl peroxyl radical has 19 kJ/mol [70]. 

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