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Reduction of Aromatic Nitro-compounds. By RALPH WINTON WEST.ON the laboratory scale, considerable difficulty is often experienced in the reduction of aromatic nitro-compounds to the corresponding amines. The difficulty of regulating the energy of the reduction often leads to decomposition of the amine, with the formation of undesirable products, Thus, the main product of the reduction by stannous chloride of o-bromonitrobenzene is aniline, whilst a considerable quantity of the free amino-acid is produced in the reduction of ethyl p-nitrobenzoate. I n other cases, the method of working up the product of the reduction is inconvenient and wasteful ; e.g., m-dinitrobenzene to m-phenylenediamine. The method here described has been found to give good yields of very pure products. The nitro-compound (1 g.-mol.) is heated to boiling on the waterbath with methylated spirit (500 c.c.) and concentrated hydrochloric acid (10 c.c.). Iron filings (170 g. for each nitro-group present in the compound) are introduced in four portions, 5 minutes being allowed between each addition. The mixture should be kept a t vigorous ebullition in order to prevent the iron from caking, and the heating continued for 2 hours after the final addition of iron. The subsequent treatment of the solution depends on the nature of the amino-compound.(a) It may be made alkaline with caustic soda (10 g.) and steamdistilled. I n this way, the first distillate of alcohol is collected separately from the turbid distillate of the substance.(b) After addition of alcoholic caustic soda equivalent to the hydrochloric acid employed, the hot liquid is filtered and the residue washed once with spirit. The bulk of the alcohol is removed by distillation, and the hydrochloride of the base precipitated by the addition of concentrated hydrochloric acid.

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