PRODUCTION OF PURE-1-NITROANTHRAQUINONE

摘要

PRODUCTION OF PURE 1-NITROANTHRAQUINONE In the preparation of pure 1-nitroanthraquinone wherein anthraquinone is nitrated in concentrated nitric acid at a temperature up to 65.degree.C, when more than 50% of the anthraquinone has been converted the reaction is discontinued by at least one of (a) cooling the reaction mixture and (b) adjusting the mole fraction of the nitric acid in the reaction mixture to a value of less than 0.86, 1-nitroanthraquinone is then precipitated by at least one of (A) adjusting the mole fraction of nitric acid to a value of from 0.7 to 0.4 and (B) lowering the temperature to below 20.degree.C, and the 1-nitro-anthraquinone which has precipitated is separated off and subjected to distillation, the improvement which comprises effecting the nitration with a nitric acid: anthraquinone molar ratio of more than 20:1, especially 25-100:1 and particularly 30-80:1.