Decomposition of cyclonite

SimeSek [15] doubted the correctness of the Vernazza equation and believed that the decomposition of cyclonite by concentrated sulphuric acid at 20-40°C may be expressed by the following empirical equation ... 

SimeSek also came to the conclusion that N20 is not liberated in the nitrometer during the decomposition of cyclonite since formaldoxime CH2=NOH is formed in the presence of formaldehyde hence the analytical results are low. 

It should be noted that the presence of water in the sulphuric acid promotes the decomposition of cyclonite. This is particularly easy when the acid contains 1-15% of water. In a strictly anhydrous medium the course of the reaction is much milder. Nitric acid which contains S03 does not cause the decomposition of cyclonite. 

According to Somlo [16] the action of a 4% solution of NaOH at 60°C produces the total decomposition of cyclonite after 5 hr. Somlo also studied the decomposition of cyclonite by concentrated sodium hydroxide and found it to be complete within 2-4 hr at 60°C. Among the decomposition products he detected nitrates, nitrites, organic acids, ammonia, nitrogen, formaldehyde and hexamethylenetetramine. 

A. J. B. Robertson [23] found that the decomposition of cyclonite at a temperature above its melting point (between 213 and 299°C) proceeds as a first order reaction. At 213°C, half the substance decomposes in 410 sec, and at 299°C in 0.25 sec. The gaseous decomposition products contain chiefly N2, N20, NO, CO and C02. According to A. J. B. Robertson the activation energy E of the thermal decomposition of cyclonite at these temperatures is 47,500 cal, log 21=18.5. The reaction rate in the liquid phase is approximately ten times greater than in the solid phase (below the melting point.)... 

Nitration with cyclonite in sulphuric acid confirms the suggestion of Sime-dek (Vol. Ill, p. 81) that the decomposition of cyclonite in sulphuric acid yields nitronium ions. 

Thennal decomposition of cyclonite was investigated by numerous authors (also Vol. Ill, p. 83) [110-115]. Maksimov [111] described several experiments of decomposition of cyclonite and octogene as solid substances and in solution. The energy of activation was calculated as E = 52.0 kcal/mol, log) o 19.1. 

Figure 55 shows the decomposition of cyclonite in solution in w-dinitro-benzene at 160-200 0. A concentration of 4% was used with the exception of the sample examined at I90 C where the concentration was 13%. The energy of activation was E 39.1 kcal/mol, logi o 14.3. One of the conclusions of the... 

Cosgrave and Owen [115] and Debenham and Owen [170] studied the decomposition of cyclonite at 195 C and 173-184 C respectively. Tlvey came to the conclusion that the initial decomposition takes place in the vapour phase and is followed by a more rapid decomposition in the liquid phase (e.g, a solution of cyclonite in 1,3,5-trinitrobenzene [170]). 

Recently Kishorc and laye 1116] examined thermal decomposition of cyclonite by differential scanning calorimetry. The curves of the decomposition arc of an S shape (similar to those of tetryl — Rg. 53). Isothermal curves are similar to Figs 55 and 56. Tlie author calculated the value of decomposition of cyclonite in an open vessel as being 41 2 kcal/mol. They also reported the values of obtained by other authors. In addition to those given in Vol. HI, p. 83 (by Robertson), they are those of ... 

Other work on thermal decomposition of cyclonite was done by 3Vilby [171 j, Rosen and Dacoas [172), Rauch and 1 anclli [173] and Batien [174],... 

An attempt to prepare cyclonite by reacting the substance (III) with silver nitrite also failed, as it resulted in total decomposition of the molecule. 

Epstein and Winkler [17] reported a preliminary examination of the kinetics of cyclonite decomposition proceeding by a homogeneous phase in acetone solution. 

Searching for ways of getting rid of these products, a method was worked out by which their decomposition was induced under strictly controlled conditions. Decomposition is caused, ifor instance, by pouring the mixture into hot water after nitration. The amount of water and the temperature are coordinated so that a concentration of 50-55% HN03 and a temperature of 70-90°C are maintained. Highly pure cyclonite is precipitated and N02 evolved from the decomposition of all unstable products. This is the so-called degassing process . 

Dilution. The liquid leaving the nitrator through the overflow passes to the diluter below. Here decomposition of unstable nitration products and precipitation of cyclonite takes place. The diluter (Fig. 21), of dimensions 265x60x115 cm, is divided into four chambers, each containing a rotary stirrer (195 r.p.m.) and a heating coil. The diluter is filled continuously up to a level of 65 cm with 55% nitric acid. As the liquid containing more concentrated acid flows in from the nitrator water is added to maintain this concentration. A temperature of 75°C is maintained in the diluter by means of the heating coils. 

When reaction is complete the whole is introduced into a battery of six diluters with water maintained at a temperature of 70-75°C. The first diluter has a capacity of 3 m3, the following four 1.5 m3 each, and the last 3 m3. Sometimes, to initiate decomposition of the unstable nitration products, the presence of a small amount of nitrogen dioxide is required. The amount of water added to the diluter should be such that it maintains a 50% concentration of HN03. At this concentration cyclonite is fully precipitated. The suspension of cyclonite in acid then flows to a battery of coolers in which it is cooled gradually to temperatures of 50, 35, and 20°C. 

This observation also appears to explain why an excess of paraformaldehyde should have a harmful influence on the yield of cyclonite. In particular, Winkler noticed that the addition of formaldehyde to a hexamine solution in aqueous acetic acid causes the decomposition of hexamine which proceeds at a rate depending on the ratio of formaldehyde to hexamine. 

Spectroscopy of cyclonite Chemical properties Thermal decomposition Preparation of cyclonite... 

A very interesting attempt was made by Boisard et aL [34] to use the rapid Raman spectrometry of 10 ns to study the structure of explosives immediately preceding the decomposition produced by a shock. Tliey obtained spectra of cyclonite after the shock and the beginning of decomposition. A displacement was observed by 11 cm" of the frequency of the bond N—NOj. This is probably due to lengthening of the bond N — N. It is expected to obtain more information in the future. 

Cyclonite is decomposed in concentrated sulphuric acid and the decomposition yielded most likely nitronium ion (Vol. Ill,p. 81). This is evidenced by the fact that a solution of cyclonite in sulphuric acid can nitrate aromatic compounds. 

According to le Roux [53] tetramethylammonium nitrate has no explosive properties it did not detonate even when initiated by a strong charge of PETN. Attempts to provoke explosive decomposition by impact failed. Le Roux suggested that the compound might be used as an ingredient of explosive mixtures, for instance blended with cyclonite or incorporated in a fusible mixture with ammonium nitrate (see Vol. III). 

S-H process (inventor Schnurr) continuous nitration of hexamethylenetetramine using highly concentrated nitric acid, accompanied by a decomposition reaction under liberation of nitrous gases, without destruction of the Cyclonite formed. The reaction mixture is then filtered to separate the product from the waste acid, followed by stabilization of the product by boiling under pressure and, if required, recrystallization. 

Cyclonite is a highly powerful explosive with a brisance greater than that of TNT. The detonation velocity is between 7 and 8 km/s. The pure compound is highly sensitive to shock, decomposing explosively. The products of decomposition are, however, harmless gases, carbon dioxide, oxygen, nitrogen, and water vapor. 

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