Picric acid structural formula

It is not customary to attempt the isolation of ketone or aldehyde intermediates (121) the formula serves merely as a reminder that once hydrolysis of the protecting enol ether or acetal occurs, the same type of structure is formed from any given dicarbonyl compound. Cyclization has been carried out in refluxing ethanolic picric acid or acetic anhydride with a few drops of sulfuric acid, but Hansen and Amstutz (63JOC393) offered excellent theoretical reasons for avoiding an excess of acid, and reported that best results (Table 3) can be obtained by refluxing the dry hydrobromide in acetic anhydride containing no sulfuric acid. 

Ammonium picrate, CjH2(N02)30NH4, is a high explosive when dry and flammable when wet. It is composed of yellow crystals that are slightly soluble in water. The four-digit UN identification number is 1310 for ammonium picrate wetted with not less than 10% water. It is used in pyrotechnics and other explosive compounds. The structure and molecular formula for ammonium picrate are shown in Figure 3.18. Notice the similarity to picric acid and TNT. You may notice that the structure and formula of ammonium picrate do not follow the usual rules of bonding. 

Trinitrophenol, also known as picric acid, is composed of yellow crystals and is a nitro hydrocarbon derivative. It is shipped with not less than 10% water as a wetted explosive. There is a severe explosion risk when shocked or heated to 572°F, and it reacts with metals or metallic salts. In addition to being flammable and explosive, it is toxic by skin absorption. Picric acid has caused disposal problems in school and other chemistry laboratories where the moisture has evaporated from the container as the material ages. When the picric acid dries out, it becomes a high explosive closely related to TNT. Picric acid has been found in various amounts in school labs across the country. In a dry condition, picric acid is dangerous and should be handled by the bomb squad. The structure and molecular formula for picric acid are shown in Figure 6.3. 

TNT and picric acid have been replaced gradually by tetryl, RDX, and nitroglycerine (Section 9-11). On the research front, chemists are continuing to explore novel structures. A case in point is octanitrocubane, synthesized in 2000, in which ring strain adds to the brisance of the compound. Its molecular formula, CgNgOig, indicates the potential to generate 8 CO2 -f 4 N2 molecules, with an associated 1150-fold volume expansion. A recent example from 2012 is the exotic salt TKX-50, in which two lone carbon atoms are surrounded by 10 nitrogens and the equivalent of 4 H2O moieties. 

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