Process for preparing phthalides

US6147227A · kind A · utility

Assignee

• BASF SE

Inventors

• Klemens Massonne · Bad Dürkheim, DE
• Rainer Becker · Bad Dürkheim, DE
• Horst Neuhauser · Dudenhofen, DE
• Horst Zimmermann · Mannheim, DE
• Wolfgang Reif · Bischofswerda, DE
• Peter Cramers · Liestal, CH
• Daniel Nardin · Horriwil, CH

Key dates

• Filing date: Apr 1, 1999
• Grant date: Nov 14, 2000
• Expiry date: Apr 1, 2019

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D307/88
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for preparing phthalides of the general formula I, ##STR1## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently hydrogen, C.sub.1-C.sub.4 -alkyl or C.sub.1 -C.sub.4 -alkoxy, by hydrogenating phthalic anhydrides of the general formula II, ##STR2## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each as defined above, with hydrogen in the presence of suspended catalysts of the Raney type in a hydrogenation apparatus by using a mixing apparatus to mix a liquid phase, which includes the catalyst and the phthalic anhydride used and resulting phthalide, and a gas phase, which includes the hydrogenating hydrogen, comprises using the mixing apparatus to introduce a mixing intensity of at least 50 W/l into the liquid phase.