Nitramines formaldehyde

The fact that nitramino groups may arise under the influence of ammonium nitrate and nitric acid in the presence of acetic anhydride is shown by the reaction in which aminomethylnitramines (obtained from nitramine, formaldehyde and, say, morpholine) are treated with acetic anhydride in the presence of ammonium nitrate and nitric acid at 55°C (Lamberton et al. [65]) ... 

Dark Decay of UDMH in Air, UDMH was observed to undergo a gradual dark decay in the 30,000-liter Teflon chamber at a rate which depended on humidity. Specifically, at 41 C and 4% RH the observed UDMH half-life was " 9 hours (initial UDMH 4.4 ppm) and at 40 C and 15% RH, the half-life was -6 hours (initial UDMH 2.5 ppm). The only observed product of the UDMH dark decay was NH3, which accounted for only -5-10% of the UDMH lost. In particular, no nitrosamine, nitramine, or hydrazone were observed. Formaldehyde dimethyIhydrazone was observed in previous studies which employed higher UDMH concentrations and reaction vessels with relatively high surface/volume ratios (, ) ... 

Irradiation of the UDMH + Oq Reaction Products. One experiment was conducted in which the UDMH + O3 reaction products (with UDMH in slight excess) were irradiated by sunlight. The results are shown in Table I and Figure 1. It can be seen that rapid consumption of UDMH, the nitrosamine, and HONO occurred, with N-nitrodimethylamine (also dimethyInitramine) and additional formaldehyde being formed. The formation of nitramine upon irradiation of the nitrosamine is consistent with results of previous studies in our laboratories (9,10), and probably occurs as shown ... 

Several color reactions were reported for heterocycbc nitramines RDX and HMX [43, 44, 53, 58]. These nitramines release formaldehyde when treated with concentrated sulfuric acid. Therefore, the use of 1,8-dihhydroxynaphthalene-3,6-disulfonic acid (chromotropic acid) in concentrated sulfuric acid — a known reagent for the detection of formaldehyde [4] — produced the expected violet-pink color. The reaction is hardly specific other compounds that release formaldehyde under similar conditions will react in the same way. 

Methylenediamines are readily synthesized from the reaction of secondary amines with formaldehyde. Many aliphatic amines are too basic for direct nitration without a chloride catalyst, and even then, nitrosamine formation can be a problem. Their conversion into intermediate methylenediamines before nitration is therefore a useful route to secondary nitramines. The success of these nitrolysis reactions is attributed to the inherent low basicity of the methylene-diamine nitrogens. 

The products obtained from these condensations are predictable for simple mono-functional substrates primary amines usually form compounds where two equivalents of primary nitramine are incorporated into the product (Equation 5.19), whereas simple secondary amines can only combine with one equivalent of nitramine (Equation 5.20). The bis-nitramine (185) is formed from the reaction of methylamine with two mole equivalents each of methyl-nitramine and formaldehyde. 

Mannich condensations involving polyamines or polynitramines are more complex, and in the case of linear dinitramines, leads to very interesting and diverse chemistry, enabling the synthesis of many cyclic nitramine products. The reaction of methylenedinitramine (168) with various primary amines in the presence of formaldehyde leads to l,5-dinitro-l,3,5,7-tetraazacyclooctanes the 3,7-dimethyl analogue (186) is isolated when methylamine is used. ... 

Some interesting nitramine products are derived from the reaction of ethylenedinitramine (2) with formaldehyde in the presence of various linear aliphatic diamines the bicycles (203) and... 

The use of primary nitramines in Mannich reactions is an important route to numerous secondary nitramines. However, a far more common route to such nitramines involves the Mannich condensation of a terminal gem-dinitroalkane, formaldehyde, and an amine, followed by IV-nitration of the resulting polynitroalkylamine. The preformed methylol derivative of the gem-dinitroalkane is often used in these reactions and so formaldehyde can be omitted. This route has been used to synthesize explosives like (92) and (209). ... 

The condensation of a primary nitramine with formaldehyde in the presence of concentrated sulfuric acid is a useful route to 1,3-dinitramines. A number of linear dinitramines have been prepared via this route including 2,4-dinitro-2,4-diazapentane (212), 3,5-dinitro-3,5-diazaheptane (213), and 5,7-dinitro-5,7-diazaundecane (214). ... 

Under aqueous conditions formaldehyde reacts with primary nitramines to form the corresponding methylol derivatives. The versatility of the terminal hydroxy group of these methylol derivatives is illustrated by their facile conversion to more reactive functional groups, like isocyanates, which can then be reacted with compounds containing hydroxy or carboxy functionality. Diisocyanates like (215), (216) and (217) have been reacted with various polyni-troaliphatic diols for the synthesis of energetic polymers. ... 

However, the yield of DPT from such reactions is often poor (15-25 %). DPT has also been synthesized from the reaction of hexamine dinitrate with acetic anhydride or cold 90 % aqueous sulphuric acid. Both methods under optimum conditions give yields of DPT of approximately 31 The reaction of nitramine (NH2NO2) with aqueous formaldehyde, followed by neutralization of the reaction mixture with ammonia to pH 5.5-6.5, gives DPT in 73 % yield based on the nitramine starting material. This last reaction presumably involves the formation of dimethylolnitramine as an intermediate (Section 5.15.4.2). 

Adolph and Cichra synthesized a number of polynitroperhydro-1,5-diazocines and compared their properties with the powerful military explosive HMX. A type of Mannich condensation was used to form the 1,5-diazocine rings the condensation of ammonia and methylamine with formaldehyde and bis(2,2-dinitroethyl)nitramine (46) forming diazocines (47) and (48) respectively. 1,3,3,7,7-Pentanitrooctahydro-1,5-diazocine (47) is A-nitrated to 1,3,3,5,7,7-hexanitrooctahydro-l,5-diazocine (52) in near quantitative yield using mixed acid. 

As early as 1910, Franchimont[16] observed that primary nitramines (and nitro-paraffins) react with formaldehyde and secondary amines (e.g. piperidine). The formation of aminomethylnitramines (IV) then occurs ... 

N-Nitration. RDX, 5, is a cyclic nitramine obtained by the nitration of hexamethylene tetramine (HMT) in the presence of an excess of concentrated nitric acid. RDX is formed by the nitration of the three outside nitrogen atoms of HMT with removal of the internal nitrogen and methylene (-CH2-) groups. RDX is produced along with ammonium nitrate (NH4NO3) and formaldehyde (HCHO) as by-products. However, another molecule of RDX can be produced by adding NH4NO3, HCHO, and acetic acid (Eqs. 12.8 and 12.9) [1]. 

The second approach to cyclic nitramines may be illustrated in the reaction of ethylenedinitramine (5) with formaldehyde to produce l,3-dinitro-l,3-diazacyclopentane (6) (Refe. 18-20). This approach has limitations when applied to more complex cyclic nitramines (Ref. 20). 

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