Tetranitromethane, reaction

The kinetics of nitration in acetic anhydride are complicated. In addition to the initial reaction between nitric acid and the solvent, subsequent reactions occur which lead ultimately to the formation of tetranitromethane furthermore, the observation that acetoxylation accompanies the nitration of the homologues of benzene adds to this complexity. 

In addition to the initial reaction between nitric acid and acetic anhydride, subsequent changes lead to the quantitative formation of tetranitromethane in an equimolar mixture of nitric acid and acetic anhydride this reaction was half completed in 1-2 days. An investigation of the kinetics of this reaction showed it to have an induction period of 2-3 h for the solutions examined ([acetyl nitrate] = 0-7 mol 1 ), after which the rate adopted a form approximately of the first order with a half-life of about a day, close to that observed in the preparative experiment mentioned. In confirmation of this, recent workers have found the half-life of a solution at 25 °C of 0-05 mol 1 of nitric acid to be about 2 days. ... 

The nitric acid used in this work contained 10% of water, which introduced a considerable proportion of acetic acid into the medium. Further dilution of the solvent wnth acetic acid up to a concentration of 50 moles % had no effect on the rate, but the addition of yet more acetic acid decreased the rate, and in the absence of acetic anhydride there was no observed reaction. It was supposed from these results that the adventitious acetic acid would have no effect. The rate coefficients of the nitration diminished rapidly with time in one experiment the value of k was reduced by a factor of 2 in i h. Corrected values were obtained by extrapolation to zero time. The author ascribed the decrease to the conversion of acetyl nitrate into tetranitromethane, but this conversion cannot be the explanation because independent studies agree in concluding that it is too slow ( 5.3.1). 

Fluorodenitration of nitroaliphatics has been primarily restricted to polyni tromethanes (Table 9) Side reactions involving potassium nitnte by-product reduce yields of fluoromtromethane The novel use of the adduct of potassium fluoride with hexafluoroacetone in diglyme as a source of fluoride ion for the fluorodenitration of tetranitromethane significantly increases the yield of fluorotn nitromethane [102] (equation 29)... 

This intermediate, produced by action of alkali on tetranitromethane, must be kept damp and used as soon as possible with great care, as it may be explosive [1], Material produced as a by-product in a nitration reaction using tetranitromethane was washed with acetone. It exploded very violently after several months storage [2],... 

Nitroisoxazolines were prepared from ALalkoxy-3,3-dinitroisoxazolidines by thermally induced P-elimination. For example, isoxazolidines 42 synthesized by a three-component reaction of tetranitromethane with two equivalents of alkenes 41, were converted into isoxazolines 43 by heating in boiling chlorobenzene <06S706>. 

Vincent, J.P., Lazdunski, M., and Delaage, M. (1970) Use of tetranitromethane as a nitration reagent. Reaction of phenol sidechains in bovine and porcine trypsinogens and trypsins. Eur. ]. Biochem. 12, 250. 

However, to be a quantitative assay of superoxide detection, Reaction (1) had to be an exothermic reaction, i.e., the difference between the one-electron reduction potentials of reagents AE° = / °[02 /02] / °[A /A] must be <0. In this case the rate constants of Reaction (1) will be sufficiently high (10s—109 1 mol 1 s ). Among traditionally applied assays, three compounds satisfy this condition cytochrome c, lucigenin, and tetranitromethane (Table 32.1). 

A ° and Rate Constants for Reaction (1) with Cytochrome c, Lucigenin, and Tetranitromethane... 

Most peroxyl radicals are oxidants18, however the peroxyl radicals formed from the reaction of O2 with the radicals induced by HTOH reacting with 1,4-cyclohexadiene are reductants, as was proven by reduction in pulse radiolysis of tetranitromethane (TNM)... 

Even simple dienes and polyenes are difficult to classify in comparison with alkenes. Whereas bromination, oxidation and reaction with tetranitromethane (TNM) can identify the number of double bonds and their location in the molecular structure, conjugated double bonds produce very complex mixtures. Furthermore, many of the tests based on 7r-complexation can also apply for aromatic moieties. An example is the TNM 7r-complex which is yellow with benzene and orange with naphthalene and the tests are therefore non-specific. 

Equally interesting processes occur in the reactions of tetranitromethane and some of its derivatives with olefins (Scheme 3.10). 

A detailed study of the polymerization of N-vinylcarbazole by tetranitromethane has provided strong evidence that in this system the reaction is propagated by a very small concentration of carbonium ions [25]. 

The formation of the trinitromethyl adduct of PBN by photolysis of PBN and tetranitromethane (Okhlobystina et al., 1975) is an unequivocal case of inverted spin trapping. These components give an orange-red CT complex in, for example, dichloromethane when this solution is irradiated by light which only can excite the CT complex (A > 430 nm) the spin adduct (N02)3C-PBN is formed via reaction (46) (Eberson et al., 1994b). This adduct is highly persistent. When the solution is acidified by —2% trifluoroacetic acid, irradiation does not lead to spin adduct formation owing to protonation of trinitromethanide ion. 

Tetranitromethane produces strongly coloured electron donor-acceptor (EDA) complexes with derivatives of the anthracene213, in dichloromethane. Specific irradiation of the charge transfer absorption band at X > 500 nm produces a rapid fading of the colour of the solutions. From these solutions, adduct 91 is obtained (reaction 24) its structure is ascertained by X-ray crystallographic diffraction. 91 is derived from an anti-addition of fragments of tetranitromethane by a multistep pathway214. 

The oxidative behaviour of glycolaldehyde towards hexacyanoferrate(III) in alkaline media has been investigated and a mechanism proposed, which involves an intermediate alkoxide ion. Reactions of tetranitromethane with the luminol and luminol-peroxide radical anions have been shown to contribute substantially to the tetranitromethane reduction in luminol oxidation with hexacyanoferrate(III) in aerated aqueous alkali solutions. The retarding effect of crown ethers on the oxidation of triethylamine by hexacyanoferrate(III) ion has been noted. The influence of ionic strength on the rate constant of oxidation of ascorbic acid by hexacyanofer-rate(III) in acidic media has been investigated. The oxidations of CH2=CHX (where X = CN, CONH2, and C02 ) by alkaline hexacyanoferrate(III) to diols have been studied. ... 

Nitration with tetranitromethane proceeds along the ion-radical ronte. Tetranitromethane is a smooth nitrating agent and mild oxidizer. It is convenient for nitration of highly activated snbstrates snch as phenols, azulene, and heterocycles in the presence of pyridine, N,iV-dialkylaniline, etc. As shown (Morkovnik 1988), these reactions inclnde one-electron transfer ... 

Studies of interactions between tetranitromethane and aryl derivatives of magnesium, tin, and mercury in sulfolane (Shevelyov et al. 1974, 1975) confirm that NO2 radical has some slight activity. For example, the reaction of diarylmercury with tetranitromethane passes through a transient step with the formation of radicals Ar and NO2. These radicals almost do not interact ... 

The reaction of alkynes with nitric acid or mixed acid is generally not synthetically useful. An exception is the reaction of acetylene with mixed acid or fuming nitric acid which leads to the formation of tetranitromethane. A modification to this reaction uses a mixture of anhydrous nitric acid and mercuric nitrate to form trinitromethane (nitroform) from acetylene. Nitroform is produced industrially via this method in a continuous process in 74 % yield. " The reaction of ethylene with 95-100 % nitric acid is also reported to yield nitroform (and 2-nitroethanol). The nitration of ketene with fuming nitric acid is reported to yield tetranitromethane. Tetranitromethane is conveniently synthesized in the laboratory by leaving a mixture of fuming nitric acid and acetic anhydride to stand at room temperature for several days. ... 

Nielsen and Bedford synthesized gem-dinitroalkanes (147) from the Michael addition of organolithium reagents to a-nitroalkenes (146) followed by quenching of the resulting nitronate anion with tetranitromethane. The same reaction using alkoxides as bases provides P-alkoxy-gem-dinitroalkanes (148). ... 

Nitryl chloride and tetranitromethane also At-nitrate amines. However, competing At-nitrosation is a particular problem and results from a redox reaction between the nitrating agent and the amine. 

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