Picric acid 24 6-trinitrophenol

The compound can be prepared from 2,4,6-trinitrophenol (picric acid [88-89-1]) by reduction with sodium hydrosulfide (163), with ammonia —hydrogen sulfide followed by acetic acid neutralization of the ammonium salt (164), with ethanolic hydrazine and copper (165), or electrolyticaHy with vanadium sulfate in alcoholic sulfuric acid (159). Heating 4,6-dinitro-2-benzamidophenol in concentrated HQ. at 140°C also yields picramic acid (166). 

Hofmann KW, H-J Knackmuss, G Heiss (2004) Nitrite elimination and hydrolytic ring cleavage in 2,4,6-trinitrophenol (picric acid) degradation. Appl Environ Microbiol 70 2854-2860. 

Wyman JF, Serve MP, Hobson DW, et ah Acute toxicity, distribution, and metabolism of 2,4,6-trinitrophenol (picric acid) in Fischer 344 rats. J Toxicol Environ Health 37 313-327, 1992... 

With phenols, thionyl chloride forms the aryl chlorides only in exceptional cases, eg, with trinitrophenol (picric acid). The reaction of thionyl chloride with primary amines produces thionyl amines. 

Explosives and related compounds have become widely recognized as serious environmental contaminants. Among the nitrosubstituted aromatic compounds causing particular concern are 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenol (picric acid), and many nitro- and/or amino-substituted aromatics that result from the manufacture and transformation of explosives. The threat posed by the presence of these compounds in soil and water is the result of their toxicity and is compounded by their recalcitrance to biodegradation. 

Poly(l,l-silole)s, SCPs catenated through the ring silicon atom, can be regarded as a new class of polysilanes. It was found that PL intensities of the toluene solution of a poly(l,l-silole) 24 (Fig. 12) could be quenched by the addition of tiny amounts of 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenol (picric acid), 2,4-dinitrotoluene (DNT), and nitrobenzene, demonstrating that poly(l,l-silole)s are potential chemosensors for explosives.41 TNT could also be detected using the polymer film. In an air stream containing 4 ppb TNT, 8.2% decrease of the PL intensity was found from the film. PL quenching can also be detected when the film contacts a 50 ppb TNT-water solution. 

Among nitrophenols 2,4,6-trinitrophenol - picric acid - is of the greatest importance. The fact that this compound was first obtained as long ago as the mideighteenth century can be explained by the exceptional ease with which nitro groups can be introduced into the aromatic ring, due to the presence of the phenol group. 

TNG = trinitroglycerine 226 TNM = tetranitromethane 311 TNMA = trinitromethylaniline TNMeL = trinitromelamine TNMes = trinitromesitylene TNM = trinitronaphthalene 356 TNPE = PETN (Spanish) 253 TNO = tetranitrooxanilide TNPh = trinitrophenol = picric acid 256... 

Japanese name for Trinitrophenol (Picric Acid), Was used in the Russo-Japanese War,... 

Properties Addition of dinitrophenol lowers the melting point of the trinitrophenol (picric acid). The mixture can be cast, and the charge is free from exudation. Detonation rate about 6300 m/sec. 

Negative substituents enhance the acidic properties of phenols, an effect opposite to that produced with aromatic amines. o and p-Chloro-phenols are considerably stronger acids than phenol itself, and o- and p-nitrophenols are still stronger. Trinitrophenol, picric acid, is a strong acid whose salts are neutral and not decomposed by carbonic acid or by ammonium salts. These salts of picric acid can be salted out of neutral solutions by sodium or potassium chloride. With negatively substituted phenols, it may be possible to separate the phenolate from solutions which are neutral or weakly alkaline to litmus. In doubtful cases, just as with the amines, the precipitated material must be studied to determine whether it is the free phenol or one of its salts. The color of the precipitate gives an indication in the case of the nitrophenols, since the free phenols have only a weak yellow color, whereas the alkali salts are deep yellow. Solubility tests with indififerent solvents may be used in the case of uncolored compounds. Only the free phenol can be separated from acidic solutions. 

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