P-nitro-aniline

OINITROTOtJUENE 2-CHLORO-4-NITROANIUNE 4>N1TR001PHENYLAM1NE PHENOLPHTHALEIN THYMOLPHTHALEIN 4-CHL0R0-2-NITR0 ANILINE p-NITRO-p-AMINOAZOBENZENE... 

White crystals, m.p. 114" C. Manufactured by reacting aniline with excess ethanoic acid or ethanoic anhydride. Chief use is in the manufacture of dye intermediates such as p-nitro-acetanilide, p-nitroaniline and p-phenylene-diamine, in the manufacture of rubber, and as a peroxide stabilizer. 

The impurities present in aromatic nitro compounds depend on the aromatic portion of the molecule. Thus, benzene, phenols or anilines are probable impurities in nitrobenzene, nitrophenols and nitroanilines, respectively. Purification should be carried out accordingly. Isomeric compounds are likely to remain as impurities after the preliminary purifications to remove basic and acidic contaminants. For example, o-nitrophenol may be found in samples ofp-nitrophenol. Usually, the ri-nitro compounds are more steam volatile than the p-nitro isomers, and can be separated in this way. Polynitro impurities in mononitro compounds can be readily removed because of their relatively lower solubilities in solvents. With acidic or basic nitro compounds which cannot be separated in the above manner, advantage may be taken of their differences in pK values (see Chapter 1). The compounds can thus be purified by preliminary extractions with several sets of aqueous buffers... 

This phenomenon is not possible in p-nitrobenzoic acid hence, p-nitrophenol is a stronger acid with respect to p-nitrobenzoic acid than is expected on the basis of a comparison of substituents in which this resonance delocalization is not an important factor. It was, therefore, recommended that Op = 1.27 be used for p-nitro derivatives of phenols and anilines, rather than the Op = 0.78 given in Table 7-10. These enhanced sigma constants, symbolized a, apply primarily to electron-withdrawing groups in reactions aided by low electron density at the reaction site. 

FIGURE 2. Peak shapes of the [M — NO]+ ions of (a) p-nitro-aniline (kinetic energy release 1240 meV) and (b) p-nitrobenzaldehyd (kinetic energy release 70 meV) Adapted from Reference 11... 

The reaction of aromatic amines with tetrazine (151) gave either 1,2,4-triazoles (154) or pyrazolo[4,3-e]-l,2,4-triazines (155), depending on the substituents. While aniline, p-toluidine, p-anisidine and p-chloroaniline afford 155, the bromo and p-nitro derivatives give 154. Intermediates 152 and 153 were postulated (Scheme 22) (82CB683). 

Aniline, 2-nitto-, p-bromination of, 55, 23 Aniline, 3-nitro-, p-bromination of, 55, 23 Aniline, 2-(trifluoromethyl), p bromination ot, 55, 23... 

Selenium acetylacetone also undergoes the following reactions 1 One molecule of the compound reacts with two molecules of p-nitro-phenylhydrazine to give p-nitrobenzeneazoacetylacetone, 1-p-nitro-phenyl-3 5-dimethylpyrazole and di-p-nitrophenylhydrazinoacetyl-acetone. With one or two molecular proportions of aniline, selenium and 1 3-dianilinoacetylacetone are obtained,... 

TNT forms charge-transfer, or 7r, complexes with polycyclic aromatic hydrocarbons, aromatic amines, and aromatic nitro compds a number of these are listed below in Table 2. The complexes with three amines (diphenylamine, diethyl-aniline, p-anisidine) have characteristic colors this forms the basis for a rapid and convenient thin-layer chromatographic analytical procedure (Ref 34) for the identification of very small amounts of TNT. (For a discussion of the many color reactions of TNT, and of composite expls containing it, see Vol 3, C405-L ff)... 

Silica gel G MeOH NH3 (100 radiochromatog.. 67 65 1.5) Folin-Ciocalteau benzene iMieOH diazotized p-nitro-. 53 28 6NH3 (79 20 1)aniline, naphtha-resorcinol... 

Some mononitrocompds, such as o- p-Nitro-aniline, p-Nitrotoluene j and some of their derivs produce orange or red color in dimethylformamide upon the addn of 0.1ml of 10% aqueous soln of tetramethylammonium hydroxide. Janovsky s reagent which is 10% aq NaOH soln may also be used) 22)G.H. Wetter, "Development of Instrumentation for Determining the Total Chromaticity and Chromaticity vs Time of... 

Battegay and Kern [58] treated methylaniline with nitrogen dioxide and obtained p- nitro-N-nitrosomethylaniline or, with nitrogen dioxide in excess, 2,4-di-nitromethylaniline. From dimethylaniline p- nitroso- and p- nitrodimethylaniline have been obtained, and with an excess of nitrogen dioxide, 2,4-dinitrodimethyl-aniline. Similar results have been obtained by Schaarschmidt, Balcerkiewicz and Gante [39],... 

For each of the diluted Standard Solutions—1, 2, and 3— plot absorbance against p-nitroaniline mM concentration. The result is a straight line that passes through the origin. Calculate the millimolar extinction coefficient (e) of each Standard p-Nitro-aniline Solution using the following formula ... 

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