Production of aminonitrodihydroxyanthraquinones by partial reduction dinitrodihydroxyanthraquinones
AssigneeBASF SE
InventorsWolfgang Elser, Gerhard Epple
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Abstract
The production of aminonitrodihydroxyanthraquinones of the formula: ##STR1## in which one X is OH and the other X is NO.sub.2 by partial reduction of the corresponding dinitrodihydroxyanthraquinone or mixtures thereof by heating at 80.degree.-250.degree. C in the presence of 1/2 to 5 times the weight thereof of an unsubstituted or substituted phenol. The reduction is accelerated by being carried out in the presence of a small amount such as 0.5-20 mol percent of an alkaline-reacting agent. Pure aminonitrohydroxyanthraquinones are obtained which are free from diaminodihydroxyanthraquinones.
Claims17
A process for the production of an aminonitrodihydroxyanthraquinone of the formula:
- ##STR3## in which one X is hydroxyl and the other X is nitro, by partial reduction, which comprises heating a reaction mixture consisting essentially of 1,5-dinitro-4,8-dihydroxyanthraquinone, 1,8-dinitro-4,5-dihydroxyanthraquinone or a mixture thereof and a reductant selected from the group consisting of unsubstituted phenol, pyrogallol, resorcinol, hydroquinone, hydroquinone monomethyl ether, substituted phenol having on the phenyl nucleus besides the phenolic -OH one or more substituents selected from the group consisting of alkyl having 1-4 carbon atoms, alkoxy having 1-4 carbon atoms, halogen and amino and mixtures thereof, at from 80.degree. to 250.degree. C until one of the two nitro groups of each respective 1,5-dinitro-4,8-dihydroxyanthraquinone and 1,8-dinitro-4,5-dihydroxyanthraquinone is reduced to the amino group and the reduction product of the above formula is then separated.
A process for the production of 1-amino-5-nitro-4,8-dihydroxyanthraquinone by partial reduction which comprises heating 1,5-dinitro-4,8-dihydroxyanthraquinone in the presence of a reductant selected from the group consisting of unsubstituted phenol, pyrogallol, resorcinol, hydroquinone, hydroquinone monomethyl ether, substituted phenol having on the phenyl nucleus besides the phenolic -OH one or more substituents selected from the group consisting of alkyl having 1-4 carbon atoms, alkoxy having 1-4 carbon atoms, halogen and amino, and mixtures thereof at from 80.degree. to 250.degree. C until only one nitro group is reduced to the amino group, and the 1-amino-5-nitro-4,8-dihydroxyanthraquinone is then separated.
Dependencies are inferred from the claim text.