Process for controlling diazotization reactions involving nitrous reactant by testing the air above the reaction batch for its content of nitrous gases and feeding nitrous reactant in accordance with said content

US4439361A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

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

Key dates

• Filing date: Feb 1, 1982
• Grant date: Mar 27, 1984
• Expiry date: Feb 1, 2002

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09B41/007
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

The disclosure relates to a process for controlling diazotization reactions. To this end, a reaction batch containing an aromatic amine and nitrous acid is vigorously agitated so as to continuously renew the surface area of the batch. The air above said surface area is exhausted at a constant rate and tested for its content of nitrous gases originating from partially decomposed nitrous acid. Nitrous acid or dissolved matter forming it under the reaction conditions is supplied to the feed amine in the proportions necessary to provide for a content between 5 and 300 ppm nitrous gases in the exhausted air.