Hydrochloric Acid → 2-Chloro-4-nitroaniline

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Reaction Steps

A process for the preparation of 2,6-dichloro-4-nitroaniline by chlorination of 4-nitroaniline with chlorine bleaching liquor in water using acids, which comprises chlorinating 1 mole of 4-nitroaniline in 3-6 moles of hydrochloric acid (HCl) or nitric acid (HNO3) in the form of a dilute, aqueous acid in the presence of a dispersing agent which is stable under the reaction conditions, the chlorination initially being carried out at 5° to 10° C. and then at 15°-20° C. and, finally, after 90-95% of the 2-chloro-4-nitroaniline intermediately formed has been converted into 2,6-dichloro-4-nitroaniline, the temperature of the aqueous suspension being increased from 15°-20° C. to 70° C., without further addition of chlorine bleaching liquor, and then by post-chlorinating, by renewed addition of chlorine bleaching liquor, at temperatures between 20° and 70° C., bringing the pH of the aqueous suspension to 9.0 and filtering off the 2,6-dichloro-4-nitroaniline formed and washing it with dilute mineral acid.

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