Methyl nitrate decomposition

A number of other gases can undergo reactions that produce decomposition flames—for instance, ethylene, ethylene oxide, methyl nitrate, ethyl nitrate, and hydrazine (CCPS 1993). 

The simplest nitrate ester is methyl nitrate, which has the chemical structure CH3ONO2. The decomposition process is given byT l... 

Decomposition of methyl nitrate under these conditions produces a spontaneous explosion. Apin, Khariton and Todes [3] on the basis of original experiments... 

The explosion of gaseous methyl nitrate subjected to the influence of an electric spark at 25°C was investigated by Zeldovich and Shaoulov [4] who found that it differs from an explosion initiated by heat. According to these authors, the fo low-ing equations express the decomposition reaction caused by an electric spark ... 

The thermal decomposition of methyl nitrate has been studied by Phillips [5], who suggested that the reactions occurring at the initial stages of decomposition... 

Gray and Rogers [6] have studied the decomposition of methyl nitrate induced both thermally and by irradiation. They postulate that a spontaneous decomposition occurs at 300°C, in the following stages initiation of the reaction according to eqn. (2) is followed by oxidation reactions ... 

Gray and Rogers are of the opinion that free radicals take part in all explosive decomposition reactions of methyl nitrate. 

Trimethylene glycol occurs in the glycerin which is produced by fermentation. There is no harm in leaving it in glycerin which is to be used for the manufacture of explosives. It may however be separated by fractional distillation. When pure it is a colorless, odorless, syrupy liquid, specific gravity (x°/4°) 1.0526 at 18°. It mixes with water in all proportions and boils at atmospheric pressure at 21 i° without decomposition. At temperatures above 15° or so, it is oxidized rapidly by nitric acid or by mixed acid. It is accordingly nitrated at 0-10° under conditions similar to those which are used in the preparation of ethyl nitrate and other simple aliphatic nitric esters (except methyl nitrate). 

The products of the thermolysis of 3-phenyl-5-(arylamino)-l,2,4-oxadiazoles and thiazoles have been accounted for by a radical mechanism.266 Flash vacuum pyrolysis of 1,3-dithiolane-1-oxides has led to thiocarbonyl compounds, but the transformation is not general.267 hi an ongoing study of silacyclobutane pyrolysis, CASSF(4,4), MR-CI and CASSCF(4,4)+MP2 calculations using the 3-21G and 6-31G basis sets have modelled the reaction between silenes and ethylene, suggesting a cyclic transition state from which silacyclobutane or a trcins-biradical are formed.268 An AMI study of the thermolysis of 1,3,3-trinitroazacyclobutane and its derivatives has identified gem-dinitro C—N bond homolysis as the initial reaction.269 Similar AMI analysis has determined the activation energy of die formation of NCh from methyl nitrate.270 Thermal decomposition of nitromethane in a shock tube (1050-1400 K, 0.2-40 atm) was studied spectrophotometrically, allowing determination of rate constants.271... 

Methyl nitrate was found to be present in the products of the decomposition of azomcthanc (Cllj-N- N-nij) when the latter substance was subjected to ultraviolet irradiation II6). This was due to an intermediate formation of CTI3O1 radical which reacted with NO to yield the nitrate ester ... 

Preparation. Coned, nitric acid (300 ml.) is chilled in ice and treated with cooling with 300 ml. of coned, sulfuric acid. In a second flask 150 ml. of methanol is cooled in ice to keep the temperature below 10° during cautious addition of 50 ml. of coned, sulfuric acid. One third of the cold nitric-sulfuric acid is placed in each of three 500-ral. Erlenmeyers, and each portion is treated with one third of the methanol-sulfuric acid mixture, added in 2-3 min. with constant swirling. Methyl nitrate separates as an almost colorless oily upper layer. After standing for 15 min. the lower layer of spent acid is separated and quenched with a large volume of water to avoid vigorous decomposition. The combined ester is washed with 25 ml. of ice-cold 22% sodium chloride solution, and the process is repeated with addition of enough alkali to produce a faintly alkaline reaction. The ester is washed free of alkali with ice-cold salt solution, then washed twice with 15 ml. of ice water, dried over calcium chloride, decanted, and used directly. Yield 190-230 g. (66-80%). Distillation is not recommended the crude ester is satisfactory for synthetic purposes. 

Some properties of methyl nitrate, such as the thermal decomposition and explosive properties are given in Vol. II. Some additional data are given by Meyer [72. 73) ... 

The decomposition of methyl nitrate will cause spontaneous explosion [47] because of the exothermal property of the reaction. 

Oxidation and reduction reactions alternately happen among products to form gases of nitrous oxide and carbon monoxide. Methyl nitrate would be oxidized through spontaneous decomposition path at 300 °C. 

The decomposition of methyl nitrate under ultraviolet is different from other decomposition pathway. 

At the initial stage of thermal decomposition of methyl nitrate, as well as other simple nitrate esters, the reactions can be written as [44] ... 

In the second series of experiments, the products from the photo-oxidation of diethyl ether, carried out in a Teflon bag reactor at ppm and ppb levels, have been determined by withdrawing vapour samples and monitoring by gas chromatography, HPLC and by chemiluminescence analysis. The major reaction products which have been measured are ethyl formate, ethyl acetate, acetaldehyde, formaldehyde, PAN, methyl nitrate and ethyl nitrate. The products observed arise from the decomposition reactions of the 1-ethoxyethoxy radical and from its reaction with oxygen. The data enable the establishment of a quantitative mechanism for the photo-oxidative reaction. In addition the rate of conversion of NO to NO2, determined by chemiluminescence analysis, shows that for each molecule of ether reacted only one molecule of NO is converted to NO2. In further end-product analyses experiments, the OH radical initiated photo-oxidation of n-hexane or the photolyses of 2- or 3-hexyl nitrites were studied to examine the... 

Methyl nitrate and methyl nitramine have been chosen as models for two other important classes of energetic materials, nitrate esters and nitramines. The X-NO2 bond dissociation energy for the nitrate was calculated to be 38 kcal/mol and that of the nitramine 47 kcal/mol, consistent with the well known trends in stability and sensitivity for nitro, nitrate and nitramine compounds. Assuming that X-NO2 bond scission is rate determining, then neither nitrate nor nitramine decomposition is affected by the presence of ammonia. 

Thompson points out that there is no evidence that adducts give other than acetates on thermolysis. The exocyclic methylene intermediate (iv) postulated by Robinson could arise by proton abstraction from a Wheland intermediate analogous to (vll) above, rather than from the adduct (in). Similarly its decomposition does not necessarily require the intermediacy of the adduct (v). The fact that i -methyl-4-nitromethylnaphthalene is the product even when the nitrating medium is nitric acid and nitromethane would then require no separate explanation. 

Although direct nitration was not possible, 2-amino-4-methylselena-zole can be directly brominated by treatment with bromine in carbon tetrachloride, the hydrogen bromide salt of 2-amino-4-methyl-5-bromoselenazole, mp 180°C (decomp.) is formed. However, all attempts to obtain the free base from this salt failed and led to complete decomposition. In this bromination, an equivalent quantity of bromine must be used excess also leads to complete destruction of the molecule. From the decomposition products an oily compound can be detected similar to bromoacetone. ... 

The kinetics of the various reactions have been explored in detail using large-volume chambers that can be used to simulate reactions in the troposphere. They have frequently used hydroxyl radicals formed by photolysis of methyl (or ethyl) nitrite, with the addition of NO to inhibit photolysis of NO2. This would result in the formation of 0( P) atoms, and subsequent reaction with Oj would produce ozone, and hence NO3 radicals from NOj. Nitrate radicals are produced by the thermal decomposition of NjOj, and in experiments with O3, a scavenger for hydroxyl radicals is added. Details of the different experimental procedures for the measurement of absolute and relative rates have been summarized, and attention drawn to the often considerable spread of values for experiments carried out at room temperature (-298 K) (Atkinson 1986). It should be emphasized that in the real troposphere, both the rates—and possibly the products—of transformation will be determined by seasonal differences both in temperature and the intensity of solar radiation. These are determined both by latitude and altitude. 

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