| 摘要 |
The invention relates to a process for obtaining alpha , alpha '-dinitro-anthraquinones of high purity from crude mixtures obtained from the dinitration of anthraquinone. Such a mixture is placed in contact with an ester having a boiling point greater than 120 DEG C. derived from a mono- or di-carboxylic acid or phosphoric acid, at a temperature between 20 DEG and 200 DEG C. or more, then, after possible cooling, the insoluble material consisting essentially of the alpha , alpha '-dinitro-anthraquinones is separated.
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