Process for preparing aldehyes

US5773667A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Helmut Bahrmann · Hamminkeln, DE
• Thomas Muller · Bad Homburg vor der Höhe, DE
• Rainer Lukas · Essen, DE

Key dates

• Filing date: May 14, 1997
• Grant date: Jun 30, 1998
• Expiry date: May 14, 2017

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P20/584
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

A process for preparing aldehydes comprising hydroformylating olefinically unsaturated compounds with hydrogen and carbon monoxide in a homogeneous phase in the presence of a catalyst system comprising rhodium complex compounds and aromatic phosphines in a molar excess and separating off the catalyst system from the hydroformylation reaction mixture by pressure filtration on a semipermeable membrane of an aromatic polyamide by carrying out the hydroformylation at a pH of 2.5 to 4.3 using a molar ratio of phosphine:rhodium of at least 60 and at a rhodium concentration of at least 10 ppm by weight, based on the olefinically unsaturated compound used, and using, as aromatic phosphines, special alkylammonium and/or arylammonium salts of sulfonated or carboxylated triarylphosphines which process leads to excellent activities and selectivities in the hydroformylation step itself and also to high retention values in the membrane filtration step.