Aniline picrates

If an ethanolic solution of picric acid is similarly added to one of aniline, no precipitation occurs, owing to the high solubility of aniline picrate in ethanol. If, however, a cold aqueous solution of aniline hydrochloride is added to a similar solution of sodium picrate and the mixture shaken, yellow crystals of aniline picrate, m.p. 165 , soon separate. 

Aniline Picrate. CgH2(N02)30H+CgH5NH2 yel ciysts mp, decomps at 165°,explds at 398° [Beil 12,120 (143)]... 

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... 

Tetryl is hydrolyzed rapidly by boiling aqueous sodium carbonate to form sodium picrate, sodium nitrite, and methylamine which escapes. It is not affected by prolonged boiling with dilute sulfuric acid. It reacts with aniline in benzene solution at ordinary temperature red crystals of 2,4,6-trinitrodiphenylamine, m.p. 179.5-180°, separate after the liquid has stood for a few hours, and extraction of the liquid with water yields an aqueous solution of methylnitramine. 

According to both the NFPA Guide and Bretherick (Refs 5 13), sulfuric acid causes explosions and/or fires when in intimate contact with a large number (over 70) of materials including acetic anhydride, acet and nitric acid, acrolein, alcohols, alcohols and hydrogen peroxide, anun hydroxide, aniline, bromine and metals, carbides, chlorates, cyclopentadiene, ethylene glycol, various hydrocarbons, hydrochloric acid, iron, mercuric nitride, powdered metals, perchlorates, picrates, pyridine, Na carbonate, steel, sucrose, vinyl acetate, and w. Illustrative... 

Nitro-N-Ethyl-N-Methyl Aniline, 02NC6H4N(CH8)(C2Hs) mw 180.21, N15-55% Prepd by heating diethylsulfate with 2-nitro N,N-dimethylaniiine, and isolation as the picrate, mp 126-7°... 

Alum, ammoniacal, 250 potassic, 201 Aluminium, 300 Amines, hydrates of, 225 Aminosuccinic acid, 294 Ammonia, 156 334. 393, 394 Ammonium, bisulpnide, 340 carbonate, 336 chloride, 200, 262, 269 cyanide, 339 nitrate, 105,175 picrate, 105 racemate, 296 sulphate, 262 tartrate, 296 Analcime, 157 Aniline, 318 Anthra ne, 289... 

The crystal and molecular structure was determined of the picrates (174) of aniline (la), its A-Me derivatives, 1,2- (lj), 1,3- (lk) and 1,4-phenylenediamine (11). Except for lj, combining with two picric acid molecules, the rest show 1 1 stoichiometry. The main structural feature is H-bonding of various strengths, with O-N distances from 267 pm for A-methylaniline to 288 pm for lj. The acid proton in these compounds sits on the N atom forming ammonium salts, as shown by the Cl-O bond distances near 125 pm for a picrate anion, rather than 130 to 134 pm for picric acid or its tt-complexes with benzene and PAH. The picrates of N-methylaniline and lk also show jr-stacking to some extent, especially in the latter case266. 

Chloro-2-methoxyaniline (2-amino-4-chloroanisole) [95-03-4] M 157.6, m 81-83 , 82-8 4 , 84 , pK 3.56. Purify the aniline by steam distillation and recrystallisation from H2O or 40% aqueous EtOH. The N-acetate forms needles from hot H2O with in 104°, the N-benzoyl derivative forms needles from aqueous EtOH with m 77-78°, and the picrate has m 194°(dec). [Raiford Colbert J Am Chem Soc 48 2657 1926, Beilstein 13 IV 879.]... 

Amines (weak base) form salts with picric acid (trinitrophenol), and all amine picrates exhibit an absorption maximum at 359 nm with a molar absorptivity of 1.25 X 10 . A 0.200-g sample of aniline, C6H5NH2, is dissolved in 500 mL water. A 25.0-mL aliquot is reacted with picric acid in a 250-mL volumetric flask and diluted to volume. A 10.0-mL aliquot of this is diluted to 100 mL and the absorbance read at,35, nm in a 1-cm cell. If the absorbance is 0.425, what is the percent purity of the aniline -... 

The synthesis of the alkaloid (XVI) was accomplished by the method of Conrad and Limpach (4). Condensation of ethyl caproylacetate with aniline gives the phenolic base (XVIII), identical with that obtained from the alkaloid, and methylation with diazomethane completes the synthesis. Comparison of the natural and synthetic bases was made through the picrates and chloroplatinates, and by isomerization to (XVII). The orientation of the substituents in the synthetic product was confirmed by the oxidation of (XVIII) with alkaline permanganate to V-caproylanthranilic acid (XX). 

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