Chemical picric acid

The Dow Chemical Company started production of chlorobenzenes in 1915 (3). Chlorobenzene was the first and remained the dominant commercial product for over 50 years with large quantities being used during World War I to produce the military explosive picric acid [88-89-1]. 

PICOPURE , hydrogen peroxide, 108 Picric acid, 108 Picrotoxin, 108 Pidilite hidustries Ltd., 174 Piedmont Chemical Industries Inc., 244 Pilot Chemical Company, 244 PILOT , chloi-pyrifos, 108 Pindone, 108... 

The nitro group is commonly encountered as a substituent in dyes and pigments of most chemical classes, but it acts as the essential chromo-phore in only a few dyes. Nitro dyes are a small group of dyes of some importance as disperse dyes for polyester and as semi-permanent hair dyes. Picric acid, 139, was historically the first nitro dye, although it was... 

FIGURE 1. Dissociation constants of picric acid in binary mixtures62. Reprinted with permission from Reference 62. Copyright (1994) American Chemical Society... 

PA PCP PCR PFA PGB PHA PID PLC PMACWA PMD POTW ppm PRH PRR psi psig PTFE PVDF PWS picric acid pentachlorophenol propellant collection reactor perfluoroalkoxy product gas burner preliminary hazards analysis proportional integral differential controller programmable logic control Program Manager for Assembled Chemical Weapons Assessment projectile mortar demilitarization (machine) publicly owned treatment works parts per million projectile rotary hydrolyzer propellant removal room pounds per square inch pounds per square inch gauge polytetrafluoroethylene (Teflon) polyvinylidene fluoride projectile washout system... 

Reactivity. Chemicals that react violently with air or water are considered hazardous examples are sodium metal, potassium metal, and phosphorus. Reactive materials also include strong oxidizers such as perchloric acid, and chemicals capable of detonation when subjected to an initiating source, such as solid, dry < 10% H2O picric acid, benzoyl peroxide, or sodium borohydride. Solutions of certain cyanide or sulfides that could generate toxic gases are also classified as reactive. The potential for finding such chemicals in a refinery is... 

Chemical/Physical. Picric acid explodes when heated >300 °C (Weast, 1986). Shock sensitive (quoted, Keith and Walters, 1992). 

The chemical structures of some common mifttary explosives are shown in Figure 1. These include the nitrate esters such as nitrocellulose (NC), NG, EGDN, and (PETN) nitroarenes such as trinitrotoluene (TNT, CH3—C6H2(N02)3), picric acid (HO—C5H2(N02)3), and 2,4,6-trinitrophenylmethylnitramine (tetryl) and nitramines such as RDX (C3H6N6O6), HMX (C4H8N8O8), and hexanitrohexa-azaisowurtzitane (CL— 20). Of these, only CL— 20 is new , that is, less than 50 years old [3]. Mixtures of oxidizers and fuels, such as AN and FO (called ANFO), are also secondary explosives. 

Uses. Chemical intermediate in manufacture of dyes, picric acid, lumber preservatives, and diaminophenol hydrochloride (a photographic developer)... 

Dermatitis from skin contact with the chemical usually occurs on the face, especially around the mouth and the sides of the nose the condition progresses from edema, through the formation of papules and vesicles, to ultimate desquamation. The skin and hair of workers handling picric acid may be stained yellow. ... 

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. 

One type of chemical approach to the analysis of liquid and solid hydrocarbons that will probably see considerable development is that involving reaction or complex formation to yield precipitates that can be separated from the unreacted mass and subsequently be treated to regenerate the hydrocarbons or class of hydrocarbons so precipitated. This field is certainly not extensively developed. In fact very few examples come to mind but among these are Gair s (21) determination of naphthalene by precipitation with picric acid determination of benzene by Pritzker and Jungkunz (52) by an aqueous solution of specially prepared nickel ammonium cyanide Bond s (8) nitrous acid method for styrene and more recently the determination of normal alkanes in hydrocarbons of more than 15 carbon atoms by adduct formation with urea as described by Zimmerschied et al. (71). 

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. 

Investigations carried out at that time revealed the outstanding value of cyclonite as an explosive its high chemical stability, which is not much lower than that of aromatic nitro compounds, and its great explosive power, which considerably surpasses that of aromatic nitro compounds, such as trinitrotoluene and picric acid. 

As an explosive octogen is superior to cyclonite in that its ignition temperature is higher (an explosion ensues in 5 sec at 335°C while with cyclonite this occurs at 260°C). The chemical stability of octogen is also superior. In a vacuum, at 120°C in 40 hr octogen evolves 0.4 cm3 of gas (cyclonite 0.9 cm3) at 150°C it evolves 0.6 cm3 of gas (cyclonite 2.5 cm3). Thus, at 150°C octogen possesses a stability of the same order as trinitrotoluene or picric acid. 

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. 

Dynamites were retained for military purposes for some time for use in demolition charges. The disadvantage of these explosives lies in their limited chemical stability. Ultimately, therefore they were replaced by explosives that remain unchanged during storage (aromatic nitro compounds such as TNT, picric acid, and more recently TNT with cyclonite or PETN). 

N 21.96% crysts, mp 295-300°(dec) si sol in hot ale Sc benz very low expin temp. It was prepd by nitrating oxanilide. Its power Sc brisance are comparable with those values of TNT Pb block expansion test — 70% Picric Acid. It is reported to be chemically unstable or reactive with moisture (Refs 6, 7, 8 8t 9) Refs 1) Beil 12, 284, (207) Sc [l65]... 

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. 

From the pamphlet Tetra-Nitro-Aniline Flurscheim, Verona Chemical Company, sole licensed manufacturers for the United States, North Newark, New Jersey, 1917( ), p. 4. Giua, op. dt., p. 317, states that the force of TNA measured in the lead block is 420 compared with picric acid 297. 

The safety limit of temperature depends on the chemical structure of the compound being nitrated. For exMnple, in the nitration of dinitrotoluene to trinitrotoluene or of phenol to picric acid, temperatures neM 120°C Mid over are considered dangerous. In the nitration of dimethylaniline to tetiyl, a temperature higher than 80°C must be considered dangerous. Esterification with nitric acid should be carried out at a temperature close to room temperature or lower. 

Chemical properties. The chlorine atom in a picryl chloride molecule is exceptionally reactive. Besides hydrolysis to picric acid when heated with water, as mentioned above, picryl chloride can yield picric acid when boiled with alcohols, according to the equation ... 

It should, however, be remembered that commercial picric acid prepared by this method contains lower nitrated phenols. To obtain a chemically pure product, commercial picric acid should be subjected to additional nitration (Arundal, Davies and ICI Ltd. [4]). 

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