Preparation of hydroxyanthraquinones

US5081270A · kind A · utility

Assignee

• BASF SE

Inventors

• Juergen Pfister · Speyer, DE
• Michael Schiessl · Altrip, DE
• Rainer Nachtrab · Ludwigshafen, DE

Key dates

• Filing date: Oct 19, 1990
• Grant date: Jan 14, 1992
• Expiry date: Oct 19, 2010

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C50/34
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

1-Hydroxyanthraquinones are prepared in an improved process by reacting phthalic anhydride or derivatives thereof with phenol derivatives in the presence of a Lewis acid as catalyst and in the presence or absence of a diluent, wherein the improvement comprises conducting the reaction in a self-cleaning apparatus having a mixing effect, at a temperature of from 120.degree. C. to 300.degree. C. for from 5 to 1,000 seconds, the self-cleaning apparatus having a mixing effect subjecting the reactants to a shear gradient of from 50 to 20,000 sec.sup.-1 with an energy input of from 0.01 to 0.2 kwh/kg of reactants.