N NITRATES

Nitration is defined in this article as the reaction between a nitration agent and an organic compound that results in one or more nitro (—NO2) groups becoming chemically bonded to an atom in this compound. Nitric acid is used as the nitrating agent to represent C-, 0-, and N-nitrations. O-nitrations result in esters. N-nitrations result in nitramines. 

Acetic anhydride and acetic acid increase the solubiUty of the two phases in each other, and they are employed for the commercial N-nitration of hexamethylenetetramine [100-97-0] (11) to form cyclotrimethylenetrinitramine [121-82-4] (RDX), (CH2)3(NN02)3. Renewed consideration has been given to replacing H2SO4 with an improved soHd catalyst to reduce the environmental problems of disposal or reconcentration of the waste acid and to increase production of desired nitrated isomers. For example, a catalyst with suitable pore size might increase the production of 4-MNT and reduce that of 3-MNT when toluene is nitrated. 

Imidazole, 1 -hydroxy-2,4,5-triphenyl-3-oxides reactions, S, 455 Imidazole, iodo-nitrodehalogenation, 5, 396-397 Imidazole, 1-iodo-reactions, S, 454 stability, S, 110 Imidazole, 2-iodo-synthesis, S, 401 Imidazole, N-iodo-, S, 393 reactions, 5, 454 Imidazole, 4-iodo-5-methyl-iodination, 5, 400 Imidazole, 2-isopropyl-4-nitro-N-nitration, 5, 351 Imidazole, 2-lithio-reactions, S, 106, 448 Imidazole, 2-mercapto-l-methyl-as antithyroid drug, 1, 171 mass spectra, 5, 358 Imidazole, 1-methoxymethyl-acylation, S, 402 Imidazole, 5-methoxy-l-methyl-reactions... 

If the benzotrifluoride contains an ammo group N-nitration in acenc acid and acetic anhydride furnishes the tnfluoromethyl nitroaminobenzene [22] C-nitration... 

Nitrat, n. nitrate, -atze,/. (Dy iVi ) nitrate discharge. -beize,/. (Dyeing) nitrate mordant. Nitration,/, nitration. — n. nitrate ion. Nitrat-kunstseide, -seide, /. nitrocellulose rayon, nitrate rayon, nitratreduzierend, a. nitrate-reducing. 

Salpeter-schwefels ure, /. nitrosulfuric acid (a mixture) nitrosylsulfuric acid, -siederei, /. saltpeter works, -stkrkemehl, n. nitrated starch, -stoff, m. nitrogen, -strauch, m. niter bush Nitraria). -ung,/. nitrification, -verbindung, /. nitrate. -waC4)ge, /. nitrometer. 

Consider lead(II) hydroxide. It can be formed when solutions of lead(n) nitrate and potassium hydroxide are mixed. Its at a certain temperature is 4.2 X 1CT15. Assume volumes are additive in all cases. 

N-nitration, in which a nitro group is attached to a nitrogen atom to form a nitramine,... 

As already mentioned (Section 1), the,prepn of most of the commonly used high expl compds involves one or more nitration reactions. Indeed, except for ammonium nitrate (AN), primary expls, and BkPdr, it is difficult to bring to mind any expl in common use (or even a laboratory curiosity) that was not prepared by nitration. In Table 1, we list the most important military and commercial high expl compds produced by nitration. We have grouped these compds by nitration type, ie C-nitration, O-nitration, and N-nitration. Note that either nitric acid or mixed acid are the nitrating agents principally employed in industry. This will be discussed further in the next section. The Table also gives Encyclopedia references for those compounds already described in previous Encyclopedia volumes... 

Common Name or N-Nitration Usual Nitrating Encyclopedia... 

Amines and amides can be N-nitrated with nitric acid, or and... 

Diphenylamine/fronCDI) Chloride/ Sulfuric Add-Sflv[Pg.72]

Mass spectra of ammonium nitrate and of a series of additional inorganic oxidizers were studied in both positive- and negative-ion mode by ESI-MS and ESI-MS/MS-CID [22, 23]. Characterization of ammonium nitrate by a series of typical cluster ions was confirmed by using isotojiicaUy labeled ammonium nitrate (ammonium- N, nitrate- N and nitrate- O) and deuterated water [22]. It was found that, at heated capiUary temperatures in the range... 

Under field eonditions, not all intermediate products are eonverted to N. Nitrate reductase, for example, eauses a decrease in the enzymatie aetivity. Denitrifieaton in the absence of oxygen is eaused by a large number of baeteria Table 15.4 lists the main microorganisms capable of denitrification. 

Nitric acid-trifluoroacetic anhydride mixtures are used extensively for nitrolysis and N-nitration reactions (see Chapters 5 and 6). The same is not true for aromatic nitrations. This reagent contains trifluoroacetyl nitrate, which can ionize to nitronium and trifluoroacetate ions in the presence of strong acid. 

A number of other amines containing electron-withdrawing groups undergo facile N-nitration (Table 5.1). The direct A-nitration of aniline derivatives is limited to amines of... 

Acetone cyanohydrin nitrate will not nitrate amines with branching on the carbon a to the nitrate group. For these substrates the use of ethyl nitrate and lithium bases is favoured. a-Aminonitriles are frequently observed as impurities under the reaction conditions because of the slow decomposition of acetone cyanohydrin nitrate to hydrogen cyanide and acetone. The need for an excess of amine during these reactions is wasteful and only practical if this component is cheap and widely available. Other cyanohydrin nitrates are less efficient N-nitrating agents. ... 

Von Runge and Triebs used a solution of dinitrogen pentoxide in chloroform for the N-nitration of both amides and imides. Solutions of dinitrogen pentoxide in chlorinated solvents are not neutral nitrating agents when amides and imides are nitrated - the presence of acidic N-H protons in these substrates leads to the formation of nitric acid. Sodium fluoride acts like a base towards nitric acid and so its addition to these reactions can increase product yield. Sodium acetate has been used for the same purpose during the nitration of n-butyl-V, V -dimethylurea. The effectiveness of dinitrogen pentoxide for the V-nitration of ureas is further illustrated by its use in the conversion of 2-imidazolidinone to N, V -dinitro-2-imidazolidinone in 90 % yield. In the presence of sodium fluoride the yield for this reaction exceeds 90 %. 

The reaction of substituted diazomethanes with ethyl Ai-nitrocarbamate, followed by hydrolysis of the ethyl N-alkyl-N-nitrocarbamate, has been used to prepare some primary arylnitramines where aromatic ring nitration is not required, and so limits the use of conventional N-nitrating agents.The method has not been fiilly investigated. 

The synthesis of 2-nitropyridazin-3(2//)-ones has been discussed in Section 8.01.5.5.5. These compounds showed excellent nitro group transfer properties allowing the N-nitration of secondary amines under mild neutral conditions <2003JOC9113>. 

Nitration of pyridines in other than nitric or sulfuric acids is of little interest here because either no reaction or N-nitration takes place (see Section 2.05.2.10). However, pyridine 1-oxide is considerably more reactive and treatment with benzoyl nitrate ultimately leads to the 3-nitro derivative (Scheme 25) (60CPB28). Annelation of a benzene ring bestows greater reactivity on the 3-position in quinoline, compared with pyridine, and reaction with nitric acid in acetic anhydride furnishes the 3-nitro derivative (ca. 6%) (Scheme 26). This isomer has also been obtained, again at low yield (6-10%), by treatment of quinoline with tetranitratotitanium(IV) in carbon tetrachloride (74JCS(P1)1751>. Nitration of benzo analogues of pyridine occurs much more readily in the benzene ring, and Chapter 2.06 should be consulted for these reactions. 

---