Hoechst Aktiengesellschaft

Siegfried Schiebler

Erwin Dietz

Hans-Tobias Macholdt

Ernst Spietschka

Wolfgang Tronich

Jorg Gitzel

Biscationic acid amide and acid imide derivatives as charge controllers

The invention relates to an ecologically favorable process for the hydrolytic decomposition of halogen-containing compounds of the formula CX.sub.4 or CHX.sub.3 or mixtures of these compounds, in which X as halogen is chlorine or bromine or a combination thereof, in an aqueous-alkaline medium, which comprises first keeping the aqueous-alkaline reaction mixture comprising the abovementioned halogen-containing compounds at a temperature of between 0.degree. and 1000.degree. C. under the autogenous pressure which is formed in a closed reaction vessel for a period of up to 10 hours and then subjecting the mixture to a heat treatment at a temperature of between 70.degree. and 150.degree. C. under the autogenous pressure which is formed therein, in the presence of sulfite. The process according to the invention is particularly suitable for hydrolytic decomposition of halogen-containing reaction products from aqueous-alkaline hypohalite oxidations. The preparation of naphthalene-1,4,5,8-tetracarboxylic acid and its tetraalkali metal salts can be carried out in an ecologically particularly favorable manner by the process according to the invention.

Oxidation process

A process for preparing very pure copper phthalocyanine pigments of the .alpha.-modification, wherein substituted or unsubstituted copper phthalocyanines having different degrees of purity are converted into copper phthalocyanine salts capable of being isolated, with the aid of suitable acids which dissolve the impurities contained in the dyestuff, wherein these salts are separated from the acid, the copper phthalocyanines of the .alpha.-modification are set free in a pure form from the copper phthalocyanine salts by the action of water and wherein the isolated copper phthalocyanine is subject in an aqueous suspension to a mechanical fine division. This process yields copper phthalocyanines of the .alpha.-modification in a very pure form without causing problems with respect to the waste water.

Process for preparing copper phthalocyanine pigments of the

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Bad Soden am Taunus, Germany

Siegfried Schiebler