Process for obtaining .alpha.,.alpha.'-dinitro anthraquinones of high purity
AssigneeProduits Chimiques Ugine Kuhlmann
InventorMaurice R. J. Vallette
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Abstract
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.degree. C. derived from a mono- or di-carboxylic acid or phosphoric acid, at a temperature between 20.degree. and 200.degree. C. or more, then, after possible cooling, the insoluble material consisting essentially of the .alpha.,.alpha.'-dinitro-anthraquinones is separated.
Claims9
In a process for obtaining .alpha.,.alpha.'-dinitro-anthraquinones of high purity from a mixture containing, in addition to the .alpha.,.alpha.' derivatives, up to 50% by weight of a member selected from the group consisting of .alpha.,.beta. and .beta.,.beta.' derivatives and mixtures thereof with mononitro-anthraquinone and anthraquinone, by treatment of said mixture with an organic solvent in which the .alpha.,.alpha.' derivatives are substantially insoluble, the improvement which comprises using as solvent an ester of a mono- or di-carboxylic acid or phosphoric acid, the boiling point of said ester at atmospheric pressure being greater than 120.degree. C.
Dependencies are inferred from the claim text.