Preparation of formaldehyde

US4584412A · kind A · utility

Assignee

• BASF SE

Inventors

• Albrecht Aicher · Bischofswerda, DE
• Gunter Lehmann · Ludwigshafen, DE
• Norbert Petri · Bischofswerda, DE
• Walter Pitteroff · Worms, DE
• Gunter Reuss · Ludwigshafen, DE
• Hans Schreiber · Ludwigshafen, DE
• Robert Sebastian · North Wilkesboro, US

Key dates

• Filing date: Jan 23, 1985
• Grant date: Apr 22, 1986
• Expiry date: Jan 23, 2005

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C45/81
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Formaldehyde is prepared by (a) passing a mixture of methanol and water with a concentration of between 50 and 90% by weight, based on the total weight of the two substances, of methanol into a packed column which possesses a packing having a total layer thickness of not less than 50 cm and a total surface area of not less than 0.5 cm.sup.2 per cm.sup.3 of packing, a liquid circulation of from 15 to 90 g/min per g/min of methanol fed to the column, and a concentration of from 10 to 45% by weight of methanol in the recycle liquid, the temperature at the point of entry of the recycle liquid in the column being from 50.degree. to 86.degree. C. and the bottom temperature being 10.degree.-25.degree. C. lower than this, i.e. from 40.degree. to 70.degree. C., (b) separating off methanol and water from the column by stripping with air, an inert gas and/or exit gas, the throughput being from 0.5 to 3 tonnes of methanol and water per hour per m.sup.2 of column cross-section, (c) converting the gaseous mixture of methanol, water, air, inert gas and/or exit gas at a space velocity of from 0.5 to 3 tonnes of methanol per m.sup.2 of catalyst bed cross-section per hour, in the presence of a silve…