Basf Aktiengesellschaft

Hermann Bidlingmaier

Norbert Mronga

Werner Ostertag

Raimund Schmid

Helmut Schmidt

Juan A Gomez

Claus Kaliba

Raymond Ellinghoven

Helmut Reichelt

Martin Koenemann

Arno Boehm

Peter Blaschka

Reinhold Rieger

Matthias Krieger

A process for preparing quaterrylene-3,4:13,14-tetracarboximides of the general formula I in whichR, R' are each independently hydrogen or optionally substituted C-C-alkyl, C-C-cycloalkyl or aryl or hetaryl;which comprises reacting a perylene-3,4-dicarboximide of the general formula IIa in the presence of a base-stable, high-boiling, organic solvent and of an alkali metal base or alkaline earth metal base, with a perylene-3,4-dicarboximide of the general formula IIb in which X is hydrogen, bromine or chlorine.

Method for producing quaterrylene-3,4:13, 14-tetracarboxy diimides by direct synthesis

Luster pigments obtainable by treating titania-coated silicate-based platelets at from 400.degree. to 900.degree. C. with a gas mixture comprising a vaporized organic compound and ammonia are useful for coloring paints, inks, including printing inks, plastics, glasses, ceramic products and decorative cosmetic preparations.

Luster pigments based on reduced titania-coated silicate-based platelets

Preparation of bluish luster pigments by treating titania-coated silicatic platelets with a reducing gas mixture, which comprises treating titania-coated silicatic platelets whose titania coating has a geometric layer thickness of from 10 to 60 nm at from 800.degree. to 900.degree. C. with a gas mixture comprising a vaporized organic compound and ammonia, and also bluish luster pigments based on silicatic platelets comprising a reduced titania coating with a geometric layer thickness of from 10 to 60 nm and CIELAB color coordinates -2.ltoreq.a*.ltoreq.2 and b*.ltoreq.-20 (measuring angle 20.degree., standard illuminant D65).

Preparation of bluish luster pigments

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Offenburg, Germany

Hermann Bidlingmaier