Ammonia nitroaniline from

Derivation (1) From l,2-dichloro-4-nitrobenzene by heating with alcoholic ammonia. (2) From the chlorination of p-nitroaniline in acid solution. Hazard Toxic by ingestion and inhalation. 

To obtain p-nitroaniline from the anilide proceed as follows HOOD.—In a beaker covered with a watch-glass boil the p-nitro-acetanilide with ten times its weight of dilute hydrochloric acid (sp. gr. 1.12) for about 20 minutes. Cool the solution, add about an equal volume of water and an excess of concentrated ammonia. When the solution is cold, filter off the p-nitroaniline,... 

Heat a mixture of 15 g. of p-nitroacetanilide and 75 ml. of 70 per cent, sulphuric acid (1) under a reflux water condenser for 20-30 minutes or until a test sample remains clear upon dilution with 2-3 times its volume of water. The p-nitroaniline is now present in the hquid as the sulphate. Pour the clear hot solution into 500 ml. of cold water and precipitate the p-nitroanihne by adding excess of 10 per cent, sodium hydroxide solution or of concentrated ammonia solution. When cold (cool the mixture in ice water, if necessary), filter the yellow crystalline precipitate at the pump, wash it well with water, and drain thoroughly. Recrystallise it from a mixture of equal volumes of rectified (or methylated) spirit and water or from hot water. Filter, wash and dry. The yield of p-nitroanihne, m.p, 148°, is 11 g. 

As shown in the previous section, N-alkyl nitroanilines 23 are obtained in the reaction of pyridone 1 with ketones 22 in the presence of amines. In this case, amines are introduced as the dialkylamino substituents. On the contrary, different reactivity is observed when ammonia is used instead of amines. The TCRT reaction proceeds to afford 2,3-dialkyl-5-nitropyridines 24 upon treatment of pyridone 1 with ketones 22 in the presence of ammonia (Table 2) [42,43]. The C4 - C5 - C6 unit is derived from pyridone 1, the C2 - C3 unit is derived from ketone, and the ring nitrogen (Nl) is from ammonia, namely the new ring consists of three components. As electrophilic nitration of pyridines is quite difficult, the present TCRT will be an alternative method for preparation of nitropyridine derivatives. 

The replacement of a nuclear substituent such as hydroxyl (-OH), chloro, (-C1), or sulfonic acid (-S03H) with amino (-NH2) by the use of ammonia (ammonolysis) has been practiced for some time with feedstocks that have reaction-inducing groups present thereby making replacement easier. For example, l,4-dichloro-2-nitrobenzene can be changed readily to 4-chloro-2-nitroaniline by treatment with aqueous ammonia. Other molecules offer more processing difficulty, and pressure vessels are required for the production of aniline from chlorobenzene or from phenol (Fig. 3). 

Reduction of 2-nitrochIorobenzene-4-sulfonic acid gives o-chlorometanilic acid which is used in making azo dyes. The real technical value of nitrochlorobenzene-sulfonic acid, however, lies in the ability of its chlorine atom to be replaced by various groups. For example, o-nitrophenol-p-sulfonic acid is obtained by treatment wiui sodium hydroxide, and this product, on reduction, yields o-aminophenol-p-sulfonic acid. An ogously, nitrochlorobenzenesulfonic acid gives o-nitroanisole-p-sulfonic acid by treatment with alcoholic methanol, and from this is obtained o-anisidine-p-sulfonic acid. The action of ammonia on nitrochlorobenzenesulfonic acid produces o-nitroaniline-p>sulfonic acid aniline and its derivatives produce o-nitrodiphenylamine-p Sulfonic acids (cf. Table II). 

A mixture of 116 g. of arsenic acid, 220 g. of concentrated sulfuric acid, 240 g. of glycerol, and 112 g. (0.81 mole) of p-nitroaniline is heated carefully imder a reflux condenser until the onset of an exothermic reaction. When the rate of reflux has decreased considerably, heat is again applied and the reflux temperature is maintained for 2.5-3 hours. The mixture is diluted with water, allowed to stand overnight, and filtered, and the filtrate is made alkaline with sodium hydroxide. The precipitated solid is separated, dissolved in hot dilute hydrochloric acid, and treated with activated carbon. Filtration followed by saturation of the filtrate with ammonia gas precipitates crystalline 6-nitroquinoline. Recrystallization from a mixture of ethanol and water gives 98 g. (70%) of product melting at 148-149°. 

Analogous para-isomers are obtained from p-chioronitrobenzene (29b). Thus animation with aqueous ammonia at 180 °C and 40 atmospheres gives p-nitroaniline (15a), a useful dye intermediate, manufactured by batch or continuous processes. With sodium sulfide, 4,4 -diaminodiphenyl sulfone (4,4 -sulfonyldianiline), also known as dapsone (32), is obtained, a product used in leprosy treatment and in the manufacture of aramides. 15a... 

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