Ciba-geigy Corporation

Hans Morawietz

Urs Karlen

Jurgen Markert

Concentrated dye solutions of the formula (1) shown in claim 1 are described. The dye solutions are notable for a long shelf life and are suitable in particular for dyeing paper.

Concentrated aqueous dye solutions for dyeing paper

A process for the production of pyranthrones or flavanthrones which comprises reacting substituted or unsubstituted 2,2'-dialkyl-1,1'-dianthraquinonyls or 2,2'-diacylamino-1,1'-dianthraquinonyls respectively in a two-phase system of aqueous organic solvents using quaternary ammonium or phosphonium compounds as catalysts.

Process for the production of pyranthrones or flavanthrones

A process for the manufacture of anthraquinone compounds of formula ##STR1## wherein X represents a hydrogen atom or a substituted or unsubstituted lower alkyl radical of 1 to 6 carbon atoms or a substituted or unsubstituted aryl radical, and the ring A can be further substituted, by sulphonating 1,5-dialkoxy-, 1,5-dicycloalkoxy- or diaryloxy-anthraquinone in the 2 and 6 positions, introducing two amino groups in positions 4 and 8 by treating the sulphonated intermediate with hydroxylamine or a salt thereof in sulphuric acid medium, in the presence of a metal catalyst, introducing the radical ##STR2## by reacting the boric acid complex of 1,5-dihydroxy-4,8-diaminoanthraquinone-2,6-disulphonic acid with a compound of formula ##STR3## saponifying the boric acid groups and splitting off a SO.sub.3 H group, which process comprises using 1,5-dialkoxy-, 1,5-dicycloalkoxy- or 1,5-diaryloxyanthraquinone as starting compounds and reacting them to give the end product of formula I.

Growing community of inventors

Aesch, Switzerland

Hans Morawietz