To 500 g. of 95 per cent ethyl alcohol in a 5-l. flask are added 170 g. (1.1 moles) of "m-nitro-p-toluidine" (3-nitro-4-aminotoluene, m.p. 112–114°, (Note 1)) and 250 g. of concentrated sulfuric acid. The solution is chilled to 10° by means of an ice bath, and a solution of 85 g. (1.2 moles) of technical sodium nitrite in the minimum quantity of water is slowly added, with stirring, the temperature being kept below 10°. The mixture is now warmed very gently on the water bath under an efficient reflux condenser (from the upper end of which a tube leads to a hood or through water) until evolution of gas ceases (Note 2). The alcohol and aldehyde are then carefully distilled off, using a fractionating column and heating in an oil or brine bath (Note 3); when the temperature of the vapors reaches 80° fractionation is stopped and the residue is distilled in a current of steam.

The oil is separated from the distillate, and the aqueous portion is shaken out once with 150–200 cc. of benzene. The united oil and extract are dried with a small quantity of calcium chloride and distilled, first under atmospheric pressure to remove the benzene, and finally under reduced pressure. The m-nitrotoluene passes over entirely at 113–114°/15 mm. On cooling, it forms a pale yellow solid which melts at 16°. The yield of pure material is 95–110 g. (62–72 per cent of the theoretical amount).