Ammonium nitrate reactivity

Of the eight nonmetals listed in Table 21.1, nitrogen is by far the least reactive. Its inertness is due to the strength of the triple bond holding the N2 molecule together (B.E. N=N = 941 kj/mol). This same factor explains why virtually all chemical explosives are compounds of nitrogen (e.g., nitroglycerin, trinitrotoluene, ammonium nitrate,... 

Release and Reactivity of tf-o-QMs Although the r 2-o-QM Os complexes 11 are stable when exposed to air or dissolved in water, the quinone methide moiety can be released upon oxidation (Scheme 3.8).16 For example, reaction of the Os-based o-QM 12 with 1.5 equivalents of CAN (ceric ammonium nitrate) in the presence of an excess of 3,4-dihydropyran led to elimination of free o-QM and its immediate trapping as the Diels-Alder product tetrahydropyranochromene, 14. Notably, in the absence of the oxidizing agent, complex 12 is completely unreactive with both electron-rich (dihydropyran) and electron-deficient (A-methylmaleimide) dienes. 

Goumont et al. exploited this kind of reactivity for the nucleophilic substitution of the hydrogen atom in position 5 by carbon nuclophiles <20030BC2192> (Scheme 18). These authors reported that 6,8-dinitrotetrazolo[l,5- ]pyr-idine 11 easily reacts with potassium nitropropenide to yield an adduct similar to those obtained with alcohols 12. This adduct when oxidized by cerium ammonium nitrate yields the nitroalkyl-substituted aromatic compound 64. 

Example Chemical Reactivity Data for Ammonium Nitrate... 

Another transient aminoxyl radical has been generated , and employed in H-abstraction reactivity determinations" . Precursor 1-hydroxybenzotriazole (HBT, Table 2) has been oxidized by cyclic voltammetry (CV) to the corresponding >N—O species, dubbed BTNO (Scheme 9). A redox potential comparable to that of the HPI —PINO oxidation, i.e. E° 1.08 V/NHE, has been obtained in 0.01 M sodium acetate buffered solution at pH 4.7, containing 4% MeCN". Oxidation of HBT by either Pb(OAc)4 in AcOH, or cerium(IV) ammonium nitrate (CAN E° 1.35 V/NHE) in MeCN, has been monitored by spectrophotometry , providing a broad UV-Vis absorption band with A-max at 474 nm and e = 1840 M cm. As in the case of PINO from HPI, the absorption spectrum of aminoxyl radical BTNO is not stable, but decays faster (half-life of 110 s at [HBT] = 0.5 mM) than that of PINO . An EPR spectrum consistent with the structure of BTNO was obtained from equimolar amounts of CAN and HBT in MeCN solution . Finally, laser flash photolysis (LFP) of an Ar-saturated MeCN solution of dicumyl peroxide and HBT at 355 nm gave rise to a species whose absorption spectrum, recorded 1.4 ms after the laser pulse, had the same absorption maximum (ca 474 nm) of the spectrum recorded by conventional spectrophotometry (Scheme 9)59- 54... 

Many of the oxidizers should be familiar to those experienced in investigating bombings. Prime examples are NH4NO3 (ammonium nitrate) and KCIO3 (potassium chlorate), both of which are utilized to make bombs on a regular basis. Other materials may appear more exotic but have equal destructive potential. It should be noted that some oxidizer families such as chlorates, nitrites, and peroxides are very reactive. When used in IE formulations, these oxidizers can create very sensitive mixtures, which need to be approached with extreme caution. 

The primary sources that are responsible for the presence of this family of compounds in the atmosphere emit NH3, N20, and NO to the troposphere, the lowest level of the atmosphere, which extends to approximately 10 km from the earth s surface. NH3 seems to undergo very little chemistry in the atmosphere except for the formation of aerosols, including ammonium nitrate and sulfates. NH3 and the aerosols are highly soluble and are thus rapidly removed by precipitation and deposition to surfaces. N20 is unreactive in the troposphere. On a time scale of decades it is transported to the stratosphere, the next higher atmospheric layer, which extends to about 50 km. Here N20 either is photodissociated or reacts with excited oxygen atoms, O (lD). The final products from these processes are primarily unreactive N2 and 02, but about 10% NO is also produced. The product NO is the principal source of reactive oxidized nitrogen species in the stratosphere. 

Ammonium nitrate is so reactive that it can explode when heated. 

Jain et al, Thermal Reactivity of Methyl-ammonium Nitrates , Proplnts Expls 1978, 3 (3), 83-87 CA 89,14S864 (1978)... 

Tetrahydropyridines are endocyclic enamines and can react readily with numerous electrophiles at the 5-position and nucleophiles at the 6-position. An example of this reactivity is a three-component reaction of iV-benzyloxycarbonyl-l,2,3,4-tetrahydropyridine 185, which reacts with primary carbamates in the presence of iodine to give 2-amino-3-iodopiperidines 186, with a toor-relationship between the substituents (Scheme 49). Tetrahydropyridine 185 also reacts with sodium azide in methanol in the presence of ceric ammonium nitrate to give 3-azido-2-methoxypiperidine 187, which can be isolated or reacted with nucleophiles in the presence of BF3-OEt2 to give 3-azido-2-alkylpiperidines 188 in which the relationship between the substituents is cis <2005T1221>. 

Ammonium nitrate, both an oxidizer and a self—reactive substance, is still used in fertilizers and as a raw material for explosives. The following two are typical accidents involving ammonium nitrate. 

A-Nitro and acetyl-substituted 1,3,5,7-tetrazocanes are important compounds as explosives and propellants <1996CHEG-II(9)705>. In the syntheses of the nitro-substituted 1,3,5,7-tetrazocanes, their processing, and application, it is possible that they come into contact with ammonium nitrate, or they are directly mixed with this oxidant. Thermal reactivity of the nitro-substituted 1,3,5,7-tetrazocanes has been examined by means of nonisothermal differential thermal analysis <2005MI11>. It has been established that impurities of ammonium nitrate can destabilize some A-substituted 1,3,5,7-tetrazocanes and that this effect is due to acidolytic attack of nitric acid. 

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