It is readily nitrated to nitrobenzene, two, and even three nitro groups being introduced if some dehydrator such as concentrated sulphuric acid be present.
Nitrobenzene, air cooling of the retort neck or of a straight tube connected with the distilling flask will suffice; or wet blotting-paper placed on the tube and the receiver immersed in water may be used.
Instances of its application are found in the separation of orthoand para-nitrophenol, the o-compound distilling and the p- remaining behind; in the separation of aniline from the mixture obtained by reducing nitrobenzene; of the naphthols from the melts produced by fusing the naphthalene monosulphonic acids with potash; and of quinoline from the reaction between aniline, nitrobenzene, glycerin, and sulphuric acid (the product being first steam distilled to remove any aniline, nitrobenzene, or glycerin, then treated with alkali, and again steam distilled when quinoline comes over).
These con-, ditions pertain in cases where distillation with steam is successfully practised, the relatively high volatility of water being counterbalanced by the relatively high molecular weight of the other component; for example, in the case of nitrobenzene and water the ratio is I to 5.
They are mostly distinguished by special trade names, and are mainly of two classes - those containing ammonium nitrate and nitrobenzene or nitronaphthalene, and those containing nitroglycerin and nitrocellulose, which are essentially weak dynamites.
Mitscherlich in 1834, may be prepared by reducing nitrobenzene in alcoholic solution with zinc dust and caustic soda; by the condensation of nitrosobenzene with aniline in hot glacial acetic acid solution; or by the oxidation of aniline with sodium hypobromite.
Azoxybenzene is also found among the electro-reduction products of nitrobenzene, when the reduction is carried out in alcoholic-alkaline solution.
The spectrum of nitrobenzene is also worth comparing with benzene and nitric acid.
Equally good comparisons have been obtained for solutions in other solvents such as acetic acid 3.88, formic acid 2.84, benzene 5.30, and nitrobenzene 6.95.
Jour., 1860, 158, p. 146); by heating aniline for red with nitrobenzene, concentrated hydrochloric acid and iron (Coupier, Ber., 1873, 6, p. 423); or by condensing formaldehyde with aniline and ortho-toluidine and oxidizing the mixture.
On warming this with copper powder, it gives a quantitative yield of nitrobenzene (A.
NITROBENZENE, C 6 H 5 NO 2, the simplest aromatic nitro compound.
Meta-dinitrobenzene is formed by the direct nitration of nitrobenzene with fuming nitric acid, the product being poured into water and recrystallized from dilute alcohol.
It is oxidized to pyridine by heating with concentrated sulphuric acid to 300° C., or with nitrobenzene to 250° C., or with silver acetate to 180° C. Being an imide it readily yields a nitroso derivative, and N-alkyl and acidyl derivatives.
Sulphuric acid, with nitrobenzene (Z.
One, and its mechanism may probably be explained as follows: The glycerin is first converted into acrolein, which combines with the aniline to form acrolein-aniline, and this product is then oxidized by the nitrobenzene: C3H803-*C,H40 (C6H5NH2)-sC6H5N: CH CH: CH2-*C9H7N.
The nitrobenzene may be replaced by arsenic acid, when the reaction proceeds much more quietly and a cleaner product is obtained (C. A.
0-phenylhydroxylamine, C 6 H 5 NH OH, is obtained in the reduction of nitrobenzene in neutral solution (e.g.
By the action of the aluminium-mercury couple and water), but better, according to C. Goldschmidt (Ber., 1896, 29, p. 2307) by dissolving nitrobenzene in ten times its weight of ether containing a few cubic centimetres of water, and heating with excess of zinc dust and anhydrous calcium chloride for three hours on a water bath.
Zinin found that on reducing nitrobenzene, a base was formed which he named benzidam.
Potassium permanganate in neutral solution oxidizes it to nitrobenzene, in alkaline solution to azobenzene, ammonia and oxalic acid, in acid solution to aniline black.
In addition to dyestuffs, it is a starting-product for the manufacture of many drugs, such as antipyrine, antifebrin, &c. Aniline is manufactured by reducing nitrobenzene with iron and hydrochloric acid and steam-distilling the product.
The purity of the product depends upon the quality of the benzene from which the nitrobenzene was prepared.
It also appears as an intermediate product in the electrolytic reduction of nitrobenzene in sulphuric acid solution.
In the production of aniline from nitrobenzene, but the use of iron is generally preferable in view of the cheapness of this metal.