Preparation of liquid formulations of basic azo dyes

US6743901B1 · kind B1 · utility

Assignee

• BASF SE

Inventors

• Michael Schmitt · Worms, DE
• Roland Merger · Bad Schönborn, DE
• Rainer Tresch · Frankenthal (Pfalz), DE

Key dates

• Filing date: Apr 10, 2003
• Grant date: Jun 1, 2004
• Expiry date: May 12, 2023

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09B69/065
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

A process for preparing liquid formulations of dyes of the general formula I where the variables are as defined in the specification by diazotizing an amine of the formula II and then coupling the diazonium salt onto a compound of the formula III and also optionally adding solubilizing additives, which comprises effecting said diazotizing at a pH set to an acidic value using pure methanesulfonic acid or at least 20 mol % mixtures of methanesulfonic acid in monobasic acids.