Explosive properties picric acid

The view then prevailed, supported by such an authority as Abel, that Picric Acid itself is not an explosive, but only its salts are. Nevertheless in 1873 Sprengel (Ref 11) proved that Picric Acid could be brought to explosion by a detonator and Turpin (Ref 12) proposed applying this property of Picric Acid by utilizing it for... 

The powdered oxidant functions as an explosive when mixed with finely divided metals, organic materials or sulfur, which increase the shock-sensitivity up to that of picric acid [1]. The hazardous properties of such mixtures increase as the particle size of the oxidant salt decreases [2],... 

Explosifs 6 I aluminium. Fr for Aluminized Explosives. Several Fr formulations are listed in Vol I of Encycl under ALUMINUM CONTAINING EXPLOSIVES, on p A146-L. Examination in 1902 by CSE (Commission des Substances Explosives) showed that some of these exp Is, as, for example, Formula. 226 (p A146 L)> were more powerful than PA (Picric Acid). More recently (1948 1950), Medard (p A148-L) determined the properties of die following Fr aluminized explosives ... 

Trinitrotoluene (TNT) was the most commonly used conventional military explosive during the twentieth century. Although it had been used extensively in the dye industry during late 1800s, it was not adopted for use as a military explosive until 1902, when the German army used it to replace picric acid. TNT was first used in warfare during the Russo-Japanese War (1904-1905). The US Army began its use in 1912. After an economical process was developed for the nitration of toluene, TNT became the chief artillery ammunition in World War I (1914—1918). The most valuable property of TNT is that it can be safely melted and cast alone or with other explosives as a slurry. 

Cyclonite is a very important explosive. The outstanding properties of RDX as an explosive are high chemical stability, not much lower than aromatic nitro compounds and high explosive power which considerably surpasses that of aromatic nitro compounds such as TNT and picric acid. RDX has a detonation velocity of8600 ms"1 and a detonation pressure of 33.8 GPa at a density of 1.77 gem"3. RDX is used in mixtures with TNT (Hexotols, Cyclotols, Compn. B) wax (Composition A) aluminum (Hexals) aluminum and TNT (HBX, Hexotonal, Torpex) etc. 

The substance possesses quite uncommon and valuable explosive properties. It is more powerful than tetryl, and considerably less sensitive to impact (as sensitive as picric acid). However, its acidic properties limit its use to a great extent. In this respect it resembles picric acid. Even so ethylenedinitramine, under the name of Haleite, has been accepted in the United States as a military explosive. During World War II, production in that country was carried out by the method outlined above according to eqn. (17)... 

Romburgh [3] was the first to prepare this substance both by nitrating ethyl-aniline and by nitrating diethylaniline. It is comparable to tetryl in its physical and chemical properties. As an explosive it is weaker than tetryl. Its sensitiveness to impact and its explosive power, measured in the lead block, are somewhat greater than those of picric acid. 

The explosive properties of hexanitrodiphenyl-/ -hydroxynitraminoethyl nitrate are similar to those of pentryl. It is slightly more stable on heating its ignition temperature lies between 390 and 400°C. It is somewhat less sensitive to impact than pentryl and rather more powerful (by 3%) in the lead block test. It requires a stronger initiator than pentryl, tetryl or picric acid, but a weaker one than trinitrotoluene. 

The molecular composition of picric acid was established in the early ninteenth century when it was the only highly-nitrated aromatic compound then known. It was evident that its oxygen content was insufficient for complete combustion (to C02 and H20). This was considered to be an adequate foundation for the erroneous theory that, because of its insufficient oxygen content, the substance has no explosive properties. It was believed that explosive properties are achieved only by mixing picric acid with oxidizing agents such as chlorates, or sodium or potassium nitrates. 

With the development of the organic chemical industry, aromatic nitro compounds of the TNT type were introduced as ingredients of composite explosives. TNT is preferable to picric acid since it has no acidic properties and hence is much less reactive. Mixtures with TNT and similar nitro compounds showed an excellent chemical stability. 

The explosive properties of mixtures with ammonium nitrate depend on the quantitative relationship between the oxidizing agent and the explosive or combustible substance. According to Parisot and Laffitte s [9, 47] investigations the explosive properties of mixtures of aromatic nitro compounds with ammonium nitrate vary with the change in composition of the system in an almost rectilinear manner. The graph in Fig. 69 shows how the rate of detonation depends on the composition of mixtures of tetryl or picric acid with ammonium nitrate. T. Urbanski et al. [48] also obtained a rectilinear relationship for nitrostarch mixtures with ammonium or sodium nitrate (Fig. 71, p. 265). 

RDX has a high chemical stability and great explosive power compared with TNT and picric acid. It is difficult to dissolve RDX in organic liquids but it can be recrystallized from acetone. It has a high melting point which makes it difficult to use in casting. However, when it is mixed with TNT, which has a low melting temperature, a pourable mixture can be obtained. Some of the properties of RDX are presented in Table 2.15. 

Trinitrophenetol or ethyl picrate, m.p. 78°, is prepared by the same methods as trinitroanisol. The explosive properties of the two substances have been studied by Desparmets and Calinaud, and by Desvergnes,72 who has reported the results of the earlier workers together with data of his own and discussions of methods of manufacture and of the explosive properties of mixtures with picric acid, ammonium nitrate, etc. Drop test with a 5-kilogram weight were as follows ... 

At present nitration is one of the most widely applied direct substitution reactions. This is due to several factors. For example nitration usually proceeds easily, its products can readily be separated from the spent acid, said there is a wide range of possibilities in the practical use of nitro compounds, both as intermediates and end products. The presence of a nitro group in the starting product made it possible to obtain a number of basic organic intermediates such as aniline said benzidine. Dyes with more than one nitro group, such as picric acid were obtained. It has been found that higher nitrated nitro compounds and nitric acid esters have explosive properties and are of practical importance. Some nitro compounds are used in perfumes. Medicinal properties have lately been discovered in certain nitro compounds, eg. chloramphenicol. 

Metal salts of picric acid may be formed by the action of picric acid on metals, their oxides or carbonates and in certain cases also on their other salts. They are crystalline substances, mostly more sensitive to friction, impact and heat, than picric acid itself. Due to their high sensitivity to stimuli, the explosive properties of picrates were known long before those of picric acid. 

On the whole the properties of trinitro-m-cresol are similar to those of picric acid. The properties of trinitrocresolates differ only slightly from those of picrates, as for example their lead salts. Ammonium trinitrocresolate has been used to some extent in Austria as a high explosive for filling shells. 

With regard to explosive power and sensitiveness trinitroresorcinol is similar to picric acid. Since its price is considerably higher than that of picric acid it is not used in explosive technology. Only lead trinitroresorcinate is of great practical importance as mi initiator (Vol. HI). On the whole the properties of trinitroresorcinol salts are similar to those of picrates. 

During World War I materials of this type were used fairly extensively, However, it has been proved that some of them can undergo hydrolysis, yielding free picric acid, thus rendering any further use of such explosives unjustifiable. In addition, most of the products have strongly toxic properties. Hence during World War II compounds of this type were used only on a small scale. 

Dinitroethane is a very powerful explosive, giving a lead block expansion of 140-150 (picric acid = 100). Its density is 1.46. It is less sensitive to impact than picric acid. Since it is highly reactive, and hence unstable, it has not found any use as explosive. It reacts most readily with bases. For example, when stored in a glass vessel it decomposes after a few weeks as the result of its contact with glass, which has basic properties. Levy suggests adding to the product an organic acid, as for example p- toluenesulphonic acid, as a stabilizer. Under the influence of bases dinitroethane may form nitroethylene, as well as other less defined products, which can readily polymerize to form resinous substances. 

Dinitrobenzofuroxan has a somewhat more explosive power than Picric Acid, but due to its slightly acidic properties and its relatively high production cost it has yet to become widely-used. 

Properties Yellow to red crystals or granules. Does not melt on heating but explodes when heated to 300°. It must be loaded in projectiles by pressing or tamping. Ammonium picrate absorbs moisture and in wet condition reacts slowly with metals, particularly copper and lead, to form picrates which are sensitive and dangerous. Its explosive strength is inferior to that of TNT, but it is very valuable because of its extreme resistance to impact, shock, and friction. It is not detonated by fulminate. Commonly used with a booster of picric acid or Tetryl. Rate of detonation 6500 m/sec. (d = 1.45). 

Properties This is one of the most, if not the most powerful explosive. It is claimed to be more sensitive than picric acid and therefore not suitable as a military explosive in shells.28... 

Properties Yellow crystals. M. P. 182°. Not very powerful when used alone. Addition of TNT, picric acid, or other nitro high explosives serves the purpose of lowering the melting point os well as that of reinforcement. Mixtures of TNX and ammonium nitrate can be loaded by compression. 

Solution We must get the properties of the explosive first. In order to find the detonation velocity and the Pa, we have to first estimate the density of the explosive. It is normal to have about 10% spare volume when packing a drum with powder, so let us assume the volume of the explosive is about 27 gallons or about 98 liters. Then the density of the picric acid would be approximately 1 g/cm . The detonation velocity at this density can be found Irom D = J + kp and we can find the values of j and k in Table 21.7 in Section IV. 

Picrate Explosives.—A most important property of the salts of picric acid, especially ammonimn picrate, is their explosive character. They are used in the manufacture of certain smokeless powders, e.g. melinite and liddite. Picric acid itself is not explosive but the salts are exploded either by percussion or ignition. Picric acid is used as an antiseptic and alleviator in the case of burns. It precipitates organic bases and proteins and is used in this way as a test for proteins. 

The data on explosive properties are also collected in the monograph by Meyer [1). Some relatively new interest was created by salts of hexyl. They possess properties similar to those of picric acid they burn readily and some of them show initiating properties. 

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