1- nitromethane

75-52-5 Chem. Abstr. Name Nitromethane lUPAC Systematic Name Nitromethane Synonyms Nitrocarbol 

2 Structural and molecular formulae and relative molecular mass 

Description Colourless, oily liquid with a moderately strong, somewhat disagreeable odour (Budavari, 1998) 

Spectroscopy data Infrared (grating [25]), Raman [296], ultraviolet [29], nuclear magnetic resonance (proton [9146], C-13[4002]) and mass spectral data have been reported (Sadtler Research Laboratories, 1980 Lide Milne, 1996) 

Solubility Slightly soluble in water (95 mL/L at 20 °C Budavari, 1998) acetone, alkali (bases), carbon tetrachloride, diethyl ether and ethanol (Lide Milne, 1996 Verschueren, 1996 American Conference of Governmental Industrial Hygienists, 1999) 

A similar analysis was carried out for two sets of nitromethane data compiled by two different students years apart. Here the two temperature regions involve 

Cl - CH2 C02Na+NaN02 N02 CH2 C02Na+NaCl N02 CH2 C02Na+H20 N02-CH3+NaHC03 

To a mixture of 500 g. of chloroacetic acid and 500 g. of cracked ice, is added, with stirring, just sufficient cold 40 per cent sodium hydroxide solution to make the solution faintly alkaline to phenolphthalein. About 360 cc. is required the temperature should not rise above 20° (Note 1). The solution is then mixed with 365 g. of sodium nitrite dissolved in 500 cc. of water and heated in a 3-I. round-bottom flask fitted with a two-hole stopper containing a bent tube of large diameter connecting with an efficient condenser (set downward for distillation) and a thermometer dipping into the liquid. The receiver should be so arranged that it can be cooled, if necessary, by a stream of water. 

The solution is heated slowly until the first appearance of bubbles of carbon dioxide, which occurs when the temperature has reached about 8o°. The flame is then removed and the reaction allowed to proceed by itself (Note 2). If no rise in temperature occurs, heat is very cautiously applied until the temperature rises to 85°, when the flame is again removed. At this temperature the exothermic decomposition of the sodium nitroacetate becomes so rapid that the temperature rises almost to ioo° without further application of external heat. If heat is applied after the temperature of the liquid reaches 85°, violent frothing will occur, with serious loss of nitromethane. If the 

When the mixture ceases to maintain its temperature spontaneously at 95-100°, heat is applied cautiously until the temperature reaches 110°. About 13 cc. of nitromethane and 200 cc. of water distil over. Further distillation gives water which contains too little nitromethane to pay for recovery. At this point enough sodium chloride and sodium carbonate have separated to cause serious bumping. 

The water separated from the nitromethane distillates is mixed with one-quarter of its weight of salt, and redistilled, yielding 10-12 cc. of nitromethane and about too cc. of water. This water on distillation gives 3-4 cc. of nitromethane and about 45 cc. of water (Note 4). 

Klaassen CD et al (eds) Casarett and Doull s Toxicology. The Basic Science of Poisons, 3rd ed, p 399. New York, Macmillan Publishing, 1986 

Kanerva L, Laine R, Jolanki R, et al Occupational allergic contact dermatitis caused by nitroglycerin. Contact Derm 24 356-362, 1991 

Reeve G et al Cardiovascular disease among nitroglycerin-exposed workers. Am J Epidemiol 118 418, 1983 

Stayner LT, Dannenberg AL, Thun M, et al Cardiovascular mortality among munitions workers exposed to nitroglycerin and dini-trotoluene. Scand J Work Environ Health 18 34-43, 1992 

Craig R et al Sixteen year follow-up of workers in an explosives factory. J Soc Occup Med 35 107-110, 1985 

The photolysis of CH3NO2 by 193 nm laser light was studied by product emission spectroscopy and molecular beam photofragment translational energy spectroscopy by Butler et al. (119). Blais (120) also studied the photolysis by the TOF method. The primary process is 

45 kcal/mol or 73% of the available energy is left for excitation of rotation and vibration of the CH3 and NO2 fragments. Another minor process corresponding to the second (smaller translational energy) peak from CH is 

The burning rates of butane-2,3 and 1,4-diol dinitrates are much less than those of mononitrates, and their combustion takes place by a different mechanism. Fowling and Smith [137] suggest unimolecular decompositions 

Flame velocities of and temperatures in nitromethane flames supported by oxygen have been measured. The global activation energy is surprisingly low, viz. 10—16 kcal. mole , depending on the fuel/oxygen ratio [126]. 

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Table 5.4 gives the specific energies of selected organic liquid compounds. Compared with the isooctane chosen as the base reference, the variations from one compound to another are relatively small, on the order of 1 to 5%, with the exception of some particular chemical structures such as those of the short chain nitroparaffins (nitromethane, nitroethane, nitropropane) that are found to be energetic . That is why nitromethane, for example, is recommended for very small motors such as model airplanes it was also used in the past for competitive auto racing, for example in the Formula 1 at Le Mans before being forbidden for safety reasons. 

The most powerful teclmique for studying VER in polyatomic molecules is the IR-Raman method. Initial IR-Raman studies of a few systems appeared more than 20 years ago [16], but recently the teclmique has taken on new life with newer ultrafast lasers such as Ti sapphire [39]. With more sensitive IR-Raman systems based on these lasers, it has become possible to monitor VER by probing virtually every vibration of a polyatomic molecule, as illustrated by recent studies of chlorofonn [40], acetonitrile [41, 42] (see example C3.5.6.6 below) and nitromethane [39, 43]. 

Hong X, Chen S and DIott D D 1995 Ultrafast mode-speoifio intermoleoular vibrational energy transfer to liquid nitromethane J. Phys. Chem. 99 9102-9... 

Nitromethane, CH3NO2, the first member of the homologous series, can, however, be readily prepared by a special reaction. When equimolecular amounts of sodium nitrite and sodium monochloroacetate are heated together in aqueous solution, the chlorine in the monochloroacetate is replaced by the nitro group, and the sodium nitroacetate thus formed undergoes hydrolysis follow ed by decarboxylation ... 

In view of the small volume of nitromethane to be manipulated, the crude nitromethane may be extracted from the aqueous distillate with ether (30-40 ml.). Dry the ethereal extract over sodium sulphate, filter through a fluted filter-paper, and then distil off the ether on a water-bath with the usual precautions (Fig. 64, p. 163 Fig, 23(E), p. 45) finally distil the residual nitromethane. 

Reactions of Nitromethane. (1) Nitromethane, although only slightly soluble in cold water, is freely soluble in sodium hydroxide solution, the alkaline solution slowly becoming yellow in colour. 

Place a few drops of nitromethane in a test tube, add about 3 times as much concentrated hydrochloric acid, and then a piece of granulated tin. The tin dissolves in the acid and the nascent hydrogen produced reduces the nitromethane to monomethylamine ... 

Dissolve a small portion of the sodium derivative in a few mi. of water in a test-tube, and add one drop of ferric chloride solution. A deep red coloration is produced, but rapidly disappears as the iron is precipitated as ferric hydroxide. The sodium (derivative (A) of the nitromethane wh dissolved in water undergoes partial hydrolysis,... 

Dissolve a few drops of nitromethane in 10% sodium hydroxide solution. Add a few crystals of sodium nitrite and shake. Now add dilute sulphuric acid drop by drop. A brownish-red coloration develops, but fades again when an excess of acid is added. The sulphuric acid has thus liberated nitrous acid, which has in turn reacted with the nitromethane to give a nitrolic acid, the sodium salt of which is CH3NO2 + ONOH = CH(N02) N0H + HgO reddish-brown in colour, probably owing to mesomeric ions of the type ... 

Nitromethane is more easily prepared by heating together equimolecular amounts of sodium monochloroacetate and sodium nitrite in aqueous solution sodium nitroacetate is intermediately formed and is decomposed to nitromethane and sodium bicarbonate. The latter yields sodium carbonate and carbon dioxide at the temperature of the reaction. 

The simpler nitrop>arafIins (nitromethane, nitroethane, 1- and 2-nitroproj)ane) are now cheap commercial products. They are obtained by the vapour phase nitration of the hydrocarbons a gaseous mixture of two mols of hydrocarbon and 1 mol of nitric acid vapour is passed through a narrow reaction tube at 420-476°. Thus with methane at 476° a 13 per cent, conversion into nitro methane is obtained ethane at 420° gives a 9 1 mixture of nitroethane (b.p. 114°) and nitromethane (b.p. 102°) propane at 420° afifords a 21 per cent, yield of a complex mixture of 1- (b.p. 130-6°) and 2-nitropropane (b.p. 120°), nitroethane and nitromethane, which are separated by fractional distillation. 

Suspend 0 25 g. of 2 4-dinitrophenylhydrazine in 5 ml. of methanol and add 0-4 0-5 ml. of concentrated sulphuric acid cautiously. FUter the warm solution and add a solution of 0 1-0-2 g. of the carbonyl compound in a small volume of methanol or of ether. If no sohd separate within 10 minutes, dUute the solution carefuUy with 2N sulphuric acid. CoUect the solid by suction filtration and wash it with a little methanol. RecrystaUise the derivative from alcohol, dUute alcohol, alcohol with ethyl acetate or chloroform or acetone, acetic acid, dioxan, nitromethane, nitrobenzene or xylene. 

Nitro compounds. Nitromethane Nitrobenzene ni-Dinitrobenzene. Amides and imides. Acetamide re-Caproamide Acetanilide Benz-anilide Phthalimide. 

A is common to all the routes we are considering but it is obviously cheaper to use a mole of cyanide or nitromethane rather than another mole of rnalonate. In fact, though, these contribute relatively httle to the cost, the main part being p-chlorobenzaldehyde. So, use whichever route you hke ... 

The value of the second-order rate constant for nitration of benzene-sulphonic acid in anhydrous sulphuric acid varies with the concentration of the aromatic substrate and with that of additives such as nitromethane and sulphuryl chloride. The effect seems to depend on the total concentration of non-electrolyte, moderate values of which (up to about 0-5 mol 1 ) depress the rate constant. More substantial concentrations of non-electrolytes can cause marked rate enhancements in this medium. Added hydrogen sulphate salts or bases such as pyridine... 

THE STATE OF NITRIC ACID IN INERT ORGANIC SOLVENTS The absence of ions in mixtures of acetic acid and nitric acid is shown by their poor electrical conductivity and the Raman spectra of solutions in acetic acid, nitromethane, and chloroform show only the absorptions of the solvent and molecular nitric acid the bands corresponding to the nitronium and nitrate ions cannot be detected. -... 

Much of the early work was inconclusive confusion sprang from the production by the reaction of water, which generally reduced the rate, and in some cases by production of nitrous acid which led to autocatalysis in the reactions of activated compounds. The most extensive kinetic studies have used nitromethane,acetic acid, sulpholan,i and carbon tetrachloride as solvents. 

It was from studies of nitration with solutions of nitric acid in nitromethane, and later in acetic acid, that Ingold and his co-workers first established the fundamental features of these reactions, and also correctly interpreted them. The use in these experiments of a large excess of nitric acid removed the problem caused by the formation of water. 

The rates of nitration of benzene, toluene, and ethylbenzene in solutions of nitric acid c. 3-7 mol 1 ) in nitromethane were independent... 

The observation of nitration in nitromethane fully dependent on the first power of the concentration of aromatic was made later. The rate of reaction of /)-dichlorobenzene ([aromatic] = 0-2 mol [HNO3] = 8-5 mol 1 ) obeyed such a law. The fact that in a similar solution 1,2,4-trichlorobenzene underwent reaction according to the same kinetic law, but about ten times slower, shows that under first-order conditions the rate of reaction depends on the reactivity of the compound. 

Nitration in acetic acid, in sulpholan and in carbon tetrachloride showed kinetic phenomena similar to those shown in nitromethane this is significant for it denies nitromethane a chemical involvement in the slow step. (Originally the rate of isomerization of nitromethane to its aci-form was believed to be a factor in the reaction. )... 

More typically its reactions showed an intermediacy of kinetic order like that observed with fluorobenzene or iodobenzene in nitromethane. 

Here we have the formation of the activated complex from five molecules of nitric acid, previously free, with a high negative entropy change. The concentration of molecular aggregates needed might increase with a fall in temperature in agreement with the characteristics of the reaction already described. It should be noticed that nitration in nitromethane shows the more common type of temperature-dependence (fig. 3.1). 

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