Picric acid salts

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. 

Picrates formed by precipitation from aqueous solutions contain water of crystallization which may desensitize them. For example, the decahydrate of ferric picrate shows no sensitiveness to friction and impact and cannot be ignited when in direct contact with a flame, whereas the anhydrous compound is exceptionally sensitive to these stimuli. 

The properties of picrates have been examined by several authors, e.g. Cheltsov [4], Will [5], Silberrad and Phillips [6], Kast [7], Krauz and Turek [8], Tucholski [9] and T. Urbanski and Sion [10], 

Tucholski determined the dehydration temperatures of picric acid salts hydrates, their melting points, initiation temperatures and temperatures preceding explosion. T. Urbanski and Sion determined their sensitiveness to impact and flame. 

The results obtained by the above authors are presented in Table 119. 

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Some of the authors had drawn attention to the expl character of Picric Acid salts, but it was not until 1830 that Welter (Ref 3) suggested the possibility of using picrates as expls. At that time Picric Acid was prepared solely by the action of nitric acid on indigo. Marchand (Ref 6) expressed the view, which proved to be true, that it was aniline, formed as an intermediate product in the process of decompn of indigo, silk and other organic matter, that yielded Picric Acid under the influence of nitric acid... 

PROPERTIES OF PICRIC ACID SALTS AND THEIR HYDRATES... 

Summary Sodium pircamate can be prepared by reacting picric acid with sodium hydroxide, and then reducing the picric acid salt to the picramate by treatment with ammonium bisulfide. After treatment with the ammonium bisulfide, the reaction mixture is filtered to remove the product. The product is then treated with carbon disulfide to dissolve precipitated sulfur. The product isthen washed, and then dried. Commercial Industrial note Part or parts of this laboratory process may be protected by international, and/or commercial/industrial processes. Before using this process to legally manufacture the mentioned explosive, with intent to sell, consult any protected commercial or industrial processes related to, similarto, or additional to, the process discussed in this procedure. This process may be used to legally prepare the mentioned explosive for laboratory, educational, or research purposes. 

For quite sensitive compositions the wet process is used. In this case an amount of water is added to the materials when they are mixed, so that they lose their explosive nature. It is also possible to add an organic solvent, but in this case it is impossible to perfectly suppress the explosive nature. The wet process is not effective for materials such as picric acid salts, which are generally sensitive even in the presence of water. 

Environmental problems of TNT manufacture Other nitroaromatics Nitro derivatives of hydrocarbons Nitro derivatives of halogcnohydrocarbons Nitrophcnols Picric acid Salts of picric acid 2,4-Dinitrorcsorcinol Purification Slyphnic acid Tetranitrodian Picric acid ethers Hexanitrodiphenylaminc (hexyl)... 

The reagent has been used for the cleavage of picric acid salts of amines. The finely divided yellow picrate is shaken with a mixture of ether and a concentrated aqueous solution of ethanolamine, and the ether solution is drawn off and extracted repeatedly with ethanolamine solution until it is no longer colored. Hiinig and Baron studied the velocity of splitting of quaternary ammonium salts on refluxing with ethanolamine. ... 

Perhaps the first of the numerous patents for mixtures of starch nitrate with oxidants, and the like, was assigned to W. Schiickher in 1889 for the production of a smokeless gunpowder. His mix included ammonium, barium, potassium, sodium and starch nitrates, together with potassium chlorate, picric acid salts, nitronaphthalene, and carbon. The starch nitrate used was probably defective in stability. 

Picric acid salts Ammonium picraic Guanidine picratc Danger produced hy picraics Tctra- and pcnia-nitro derivatives of phenol Tctranitruphenol PentanitrophennI Nitro derivatives of cresols 2.4,6-T ri n i t lo-m >creso I Physical properties C hcmical properties... 

The crystal structure of the red picric acid salt of D,L-tryptophan-methanol was determined by X-ray diffraction methods 141). The indole and picrate planes are stacked, with interplanar spacing of 3.3-3.5 A. The stacked pairs are relatively isolated and without k-k interactions between adjacent pairs. The stacking interactions appears to be of the donor-acceptor (charge-transfer) type. The vibrational spectrum of tryptophan picrate contains a strong band at 1740 cm which is not observed in the spectra of either of the components, and is attributed to the C = 0 stretching vibration (250). 

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