Hoechst Aktiengesellschaft

Farbwerke Hoechst Aktiengesellschaft

Friedrich Wilhelm Weingarten

Klaus Hunger

Joachim Ribka

Wolfgang Rieper

Ernst Klappert

Process for the aftertreatment of the azo pigment of the formula ##STR1## C.I. PIGMENT ORANGE 36 wherein the crude pigment obtained after coupling is heated to temperatures from 100.degree. to 150.degree. C. in dry or wet condition in a solvent which is water-immiscible or not indefinitely water-miscible and the pigment is isolated in known manner. The pigment aftertreated in this way shows substantially improved hiding power while the same pigment prepared in the usual way has poor hiding power and can not be used in stoving lacquers.

Azo pigment having improved hiding power and a process for its

The compound of the formula: ##STR1## is a valuable pigment of high fastness properties and high covering power.

Monoazo pigment derived from acetoacetylamino benzimidazolone

3-Amino-4-lower carboalkoxy-benzoic acid-4'-phenoxy-anilides which may be halogenated in the phenoxy nucleus are obtained by reacting the corresponding 4-carboalkoxy-benzoyl chlorides having in 3-position a group capable of yielding the amino group with a 4-amino-diphenyl ether which may be halogenated in the phenyl nucleus which is not substituted by the amino group, and setting free the amino group from the group capable of yielding it. The products are diazo components for azo pigments, especially of the 2-hydroxy-3-naphthoic acid arylide type.

3-Amino-4-carboalkoxy-benzoic acid 4'-phenoxy-anilides

Diazotation of 3-amino-4-carboalkoxy-benzoic acid (4'-phenoxy)-anilides which may be halogenated in said phenoxy nucleus and coupling on 2-hydroxy-3-naphthoic acid-(4'-benzoylamino)-anilides which may be further substituted in said anilide nucleus by halogen, lower alkyl or lower alkoxy, yields azo compounds which are valuable pigments of clear shades and high fastness to migration, light and weather.

Growing community of inventors

Liederbach, Taunus, Germany

Friedrich Wilhelm Weingarten