Continuous production of azo pigments

US4454067A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Hartmut Behringer · Nidderau, DE
• Kurt Karrenbauer · Lechenich, DE
• Heinrich Rehberg · Kornwestheim, DE

Key dates

• Filing date: Oct 9, 1979
• Grant date: Jun 12, 1984
• Expiry date: Oct 9, 1999

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S534/07
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to a process for the continuous manufacture of azo pigments, wherein a coupling component is reacted, inside a reaction zone filled with a previously produced suspension of the azo pigment to be made, with an aqueous solution of a diazo component at 10.degree. to 60.degree. C. and over periods of 0.2 to 4 hours. To this end, an aqueous suspension or solution of the coupling component is passed in substantially laminar flow upwardly through a cylindrical reaction zone arranged in upright position; the aqueous solution of the diazo component is introduced through 2 to 50 serially arranged inlets opening laterally into the reaction zone, the diazo component being admitted in quantities decreasing from below to above and the stoichiometric end point of the coupling reaction being established at the upper most inlet opening into the reaction zone; the pH-value typical of each reaction is established by introducing dilute alkali liquor through 2 to 50 serially arranged inlets opening laterally into the reaction zone, the respective diazo component and alkali liquor inlets being arranged at different levels with respect to each other.