Process for the manufacture of acrylic acid

US3985800A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Heinz Erpenbach · Cologne, DE
• Klaus Gehrmann · Lechenich, DE
• Winfried Lork · Lechenich, DE
• Peter Prinz · Ethel, US

Key dates

• Filing date: Aug 31, 1973
• Grant date: Oct 12, 1976
• Expiry date: Aug 31, 1993

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01J35/633
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

Production of acrylic acid by reacting acrolein with molecular oxygen in the presence of steam and, if desired, inert gases at elevated temperature in contact with a fixed bed of cobalt molybdate catalyst prepared by precipitating cobalt molybdate from the combined aqueous solutions of a cobalt salt, of a molybdenum compound and of ammonia at a temperature of about 60.degree.C and at a pH of at most 7; filtering off, washing and drying the precipitate at a temperature of at least 100.degree.C; heating the dry cobalt molybdate for several hours at elevated temperatures, grinding and transforming it into shapes; and sintering the cobalt molybdate shapes for several hours. The acrylic acid is more particularly produced in contact with a catalyst prepared by combining the aqueous solution of the cobalt salt with that of the molybdenum compound in the atomic ratio of Co:Mo of about 1.05:1; establishing in the combined solutions a pH between 3.8 and 6.0; drying the precipitate at 110.degree.-170.degree.C; heating the dry cobalt molybdate to temperatures between 250.degree. and 550.degree.C; and sintering the cobalt molybdate shapes at temperatures between 500.degree. and 700.degree.C so …