Tetryl manufacture

According to Sokolov [58] dimethylaniline used for the manufacture of tetryl should be a pale-yellow liquid, s.g. 0.955-0.960 at 15°C, b.p. 192-194°C, not less than 95% of the substance distilling between 192.7 and 193.7°C. It must not contain water or aniline. Only traces of methylaniline are permissible. 

The nitric and sulphuric acids should be purified to the extent usually required for nitrating acids. Nitric acid of 92-98% concentration, containing not more than 3% of nitric oxides is commonly utilized. The concentration of sulphuric acid may vary between 96 and 99%. The nitrating mixture should be rich in nitric acid, i.e. containing not less than 65% of HN03. 

In the manufacture of tetryl, it is usual not to nitrate dimethylaniline directly, but to dissolve it first in concentrated sulphuric acid and then to nitrate the dimethylaniline sulphate so obtained. Straightforward nitration of dimethylaniline proceeds so violently, that it can be carried out only under the special conditions described on pp. 42-43. Many years experience of tetryl manufacture has shown that the ratio of sulphuric acid to dimethylaniline should not be lower than 3 1, a smaller amount of sulphuric acid may be detrimental to the nitration process. (Nitration by a periodic (discontinuous) method may cause ignition in the nitrator due to the fact that 

The lay-out of a plant for dissolving dimethylaniline in sulphuric acid (according to Sokolov [58]) is shown, with some modifications, in Fig. 7. It comprises a dosing tank (i) for sulphuric acid and dosing tank (2) for dimethylaniline. First, 14,400 kg of 96% sulphuric acid are poured into reactor (3) followed by 1000 kg of dimethylaniline maintaining the temperature between 25 and 30°C. The dimethylaniline is poured in over a period of about 3 hr, and the contents of the reactor are then maintained for 30 min at 40°C and finally cooled to 20°C. The solution of dimethylaniline sulphate so obtained is pumped over to container (4), whence it flows down to nitrator (J). 

Before nitration the solution of dimethylaniline sulphate is tested for the presence of free dimethylaniline by treating a test sample with a large amount of water. If free dimethylaniline is present the solution is cloudy. This test is of great importance (see above). 

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Tetryl manufacture Nitration of dimethytaniline The production of dimethylanilinc sulphate Nitration Washing the tctr> l Crystallization from benzene Crystallization from acetone Nitration of dinitromethylaniline Homologues and analogues of tetryl... 

Figure 8-35. Benzidine derivatives during tetryl manufacture.

Before proceeding to describe the manufacture of the nitramines, RDX and Tetryl, a few general remarks about the preparation of nitramines... 

Trinitrotoluene DNT Tetryl Primer materials < s Nitrocellulose j Nitroglycerin 1 j NC-based propellants j Ball Powder j 0> > o PL. -o ra 55 Acid manufacture J Filling of warheads Mfg of extruded rocket grains j Mfg of cast rocket grains... 

The 5,168-acre Alabama Army Ammunition Plant tract, on the banks of the Coosa River in Talladega County, AL, is 4 miles north of Childersburg, AL (4). Plant operations, between 1942 and 1945, left residues from the manufacture of diphenylamine, TNT, DNT, and tetryl. Some of these compounds have been found on the site, and others are suspected. The shallow water table, draining to the Coosa River, is probably contaminated, but only deeper, uncontaminated aquifers would be used as the source for... 

Although the requirement for flame sensitiveness is the main consideration for initiating explosives for plain detonators, others are important in manufacture. The explosive must be capable of compression into a coherent mass and at the same time leave the equipment free from adhesions. Lead azide can be somewhat deficient in cohesion, and to improve this a small proportion of tetryl is sometimes added to the... 

Similar unsatisfactory cook-off prematures were obtd with Caliber. 50 Explosive Bullet developed by die Hunter Manufacturing Co and submitted in 1943 to tests at Aberdeen Proving Ground. The bullet had a firing pin, a LA detonator, an arming wire in the nose, and an expl chge of 15 grains of Tetryl... 

In the U SA, tetryl has not been considered for use in new explosive trains since 1973, however, it is still manufactured and used in Germany and India. On the contrary, it is no longer synthesized in the UK as both the material itself and its manufacture are considered to pose health hazards. 

This rearrangement, which is of great importance for the manufacture of tetryl, will be illustrated when the production of this substance is discussed. 

According to the German (Griesheim) method [60] tetryl is manufactured in two stages first dinitromethylaniline is prepared and this is then nitrated. 

Here, one methyl group is oxidized and at the same time the benzene nucleus is nitrated in the 2-, 4- and 6-positions. Recently-developed techniques for the manufacture of tetryl treat methylamine with 2,4- or 2,6-dinitrochlorobenzene to give dinitrophenylmethylamine. This is then nitrated to tetryl. In both processes purification is carried out by washing in cold and boiling water, the latter hydrolysing the tetra-nitro compounds. Finally, the tetryl is recrystallized by dissolving in acetone and precipitated with water, or recrystallized from benzene. 

The nitration of aniline in the presence of a large amount of strong sulfuric acid results wholly in the formation of m-nitro-aniline, but the similar nitration of dimethylaniline gives principally a mixture of the ortho- and para-derivatives. Mono-methylaniline stands between aniline and dimethylaniline in respect to the orienting effect of its amino group it yields a considerable amount of the m-nitro- compound—and dimethylaniline is preferred for the preparation of tetryl. Commercial dimethylaniline contains a certain amount of monomethylaniline, from which it is extremely difficult to free it, and this in the manufacture of tetryl is converted in part into 2,3,4,6-tetranitro-phenylmethylnitramine, or m-nitrotetryl, pale yellow, almost white, crystals from benzene, m.p. 146-147.087... 

No m-nitrotetryl is produced if pure dimethylaniline is used in the usual process for the manufacture of tetryl. The amount of this impurity in the usual process depends upon the amount of monomethylaniline which may be present. A large excess of sulfuric acid tends toward the production of m-nitro compounds, but a reduction in the amount of sulfuric acid is not feasible for this increases the amount of benzene-insoluble material. m-Nitro-tetryl reacts with water, as TNA does the nitro group in the 3-position is replaced by hydroxyl, and m-hydroxytetryl or 2,4,6-trinitro-3-methylnitraminophenol, yellow crystals from water, m.p. 183°, is formed. This substance resembles picric acid and forms explosive salts. It is readily soluble in water, and... 

At the time of the first World War the methyl alcohol which was needed for the preparation of tetryl was procured from the distillation of wood. It was expensive and limited in amount. Formaldehyde was produced then, as it is now, by the oxidation of methyl alcohol, and a demand for it was a demand upon the wood-distillation industry. Formaldehyde was the raw material from which methylamine was produced commercially, and the resulting methylamine could be used for the preparation of tetryl by the alternative method from dinitrochlorobenzene. It was also the raw material from which certain useful explosives could be prepared, but its high price and its origin in the wood-distillation industry deprived the explosives in question of all but an academic interest. With the commercial production of synthetic methyl alcohol, the same explosives are now procurable from a raw material which is available in an amount limited only by the will of the manufacturers to produce it. 

At a time when the only practicable methods for the preparation of nitromethane were the interaction of methyl iodide with silver nitrite and the Kolbe reaction from chloracetic acid, the explosive was far too expensive to merit consideration. The present cheap and large scale production of nitromethane by the vapor-phase nitration of methane and of ethane has altered the situation profoundly. Trimethylolnitromethane trinitrate is an explosive which can now be produced from coke, air, and natural gas. Nitromethane too has other interest for the manufacturer of explosives. It may be used as a component of liquid explosives, and it yields on reduction methylamine which is needed for the preparation of tetryl. 

Tetryl [2,4,6-trinitrophenylmethylnitramine, C6H2(N02)3NCH3N02] is manufactured by the action of mixed sulfuric and nitric acid on dimethyl-aniline in a multiple-stage nitration. 

Tetryl is a highly brisant, very powerful explosive, with a satisfactory initiating power which is used in the manufacture of primary and secondary charges for blasting caps. Owing to its relatively high melting point, it is employed pressed rather than cast. 

Tetryl is a synthetic substance that was used to make explosives, mostly during World War I and World War II. It is no longer manufactured or used in the United States. The chemical name for tetryl is N-methyl-N,2,4,6-tetranitroaniline. Other commonly used names are 2,4,6-trinitrophenyl-N-methylnitramine, nitramine, tetralite, and tetril. Stocks of tetryl are found in storage at military installations and are being destroyed by the Department of Defense. Tetryl was frequently manufactured as pellets or powder. Under certain manufacturing conditions, it could exist in the air as a dust. Tetryl is a yellow, crystal-like solid at room temperature. It dissolves slightly in... 

Tetryl may be released to the air, water, and soil when old stores of the explosive ate destroyed by exploding or burning. However, tetryl has not been measured in air during any of these activities. Tetryl that was manufactured or stored at military installations, like Army ammunition plants, may still be present in the soil and water at or around these sites. Tetryl is not likely to evaporate into air from water or soil surfaces. However, tetryl may be present in air associated with dust from these sites. Tetryl appears to break-down rapidly in some soils. Picric acid, is one of the break down products of tetryl in soil. Tetryl probably does not easily travel from soil to groundwater. Erosion of soil from contaminated sites may release tetryl to nearby surface water. Once it is in the water, tetryl may dissolve or associate with small particles of suspended solids, sediments, or organic debris. Some of these particles will settle to the bottom. Tetryl breaks down rapidly in sunlit rivers and lakes but much more slowly in groundwater. It is not known whether tetryl will build up in fish, plants, or land animals. See Chapters 4 and 5 for more information on tetryl in the environment. 

The only studies located regarding health effects in humans after inhalation exposure to tetryl were case studies and other reports of workers exposed to tetryl dusts in manufacturing plants during World War I and World War II. Little information was available regarding the number of people exposed or the duration and level of exposure. Since exposure was to the tetryl-laden dusts, the effects could have been caused by inhalation, direct skin contact, or by swallowing. The dermal effects noted in these studies were most likely caused by direct skin contact and are described in Section 2.2.3. It is unknown whether the other effects were caused by inhaling or by swallowing tetryl therefore, in this profile, it is assumed that the primary route of exposure was inhalation. 

Body Weight Effects. Weight loss was reported in three workers exposed to tetryl for 1 -4 years during the manufacture of explosives (Hardy and Maloof 1950). Anorexia was reported in three of eight workers similarly exposed to tetryl for a year or more (Hardy and Maloof 1950). Anorexia and weight loss have been reported by other authors as well (Brabham 1943 Fischer and Murdock 1946 Troup 1946 Witkowski et al. 1942) and may affect as many as 10% of exposed workers (Witkowski... 

Only two reports were located that discussed possible effects of tetryl on the reproductive system. Two women employed in a plant that manufactured explosives containing tetryl during World War II (concentrations of tetryl dust and exposure duration were not given) reported increased durations... 

Several studies are available regarding health effects in humans exposed to tetryl in munitions manufacturing plants. In most studies, the number of workers or the duration and level of exposure were not provided. These studies were conducted during World War I and World War II when tetryl was being manufactured in large quantities. The workers were exposed by both dermal and inhalation routes, and it is possible that some of the dusts were swallowed. The toxic effects, other than dermal and ocular effects, are described in Section 2.2.1, Inhalation Exposure. 

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