Hoechst Aktiengesellschaft

Hans-Gerd Elinkmann

Ernst Spietschka

Siegfried Schiessler

Emmerich Paszthory

Mixtures of isomers of benzoxanthene and benzothioxanthene dyestuffs of the formulae ##STR1## wherein X is oxygen or sulfur, R optionally substituted alkyl, acyl or arylsulfonyl, R.sub.1 and R.sub.2 are hydrogen or halogen, alkyl, aryl, acyl, acyloxy, carbalkoxy, alkoxy, nitro, alkylthio or alkylsulfonyl or they form together a condensed benzene ring, R.sub.3 and R.sub.4 are hydrogen or halogen, alkyl, alkoxy, aryl, carbalkoxy or nitrile, R.sub.5 and R.sub.6 are hydrogen or optionally substituted alkoxy, are obtained by condensing the corresponding benzoxanthene or benzothioxanthene-3,4-carboxylic acid anhydrides or esters with phenyl acetic acid anhydrides or esters in the presence of alkali at a temperature of about 150.degree. to 260.degree. C. and alkylating or acylating the so-obtained hydroxy intermediates without previous isolation thereof when condensation and alkylation or acylation are performed in a polar organic solvent.

Process for preparing benzoxanthene and benzothioxanthene dyestuffs

Highly pure .alpha.-copper phthalocyanine is obtained when a product regenerated from .alpha.-copper phthalocyanine sulfate by hydrolysis with water is aftertreated in an aqueous medium containing a polar organic non-aromatic compound which is water-soluble or liquid. The aftertreated product has an especially high tinctorial strength, is very easily dispersible and has a very pure reddish-blue shade.

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Frankfurt-am-Main, Germany

Hans-Gerd Elinkmann