| 摘要 |
95-99% pure 4,5-dinitro-1,8-dihydroxyanthraquinone which is essentially free from by-products is obtained by "direct nitration" of 1,8-dihydroxyanthraquinones or 1,8-dimethoxyanthraquinones if the concentrations of acid are chosen such that, when the nitration reaction and, if appropriate, the saponification reaction have ended, an 80-100% strength sulphuric acid is present, or such a sulphuric acid concentration is established by adding water, and the 4,5-dinitro-1,8-dihydroxyanthraquinone which crystallizes out is separated off.
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