Manufacture of symmetrical dialkylureas

US4178309A · kind A · utility

Assignee

• BASF SE

Inventors

• Dietrich Luetzow · Schifferstadt, DE
• Norbert Neth · Frankenthal (Pfalz), DE
• Ulrich Wagner · Bernburg, DE
• Klaus Volkamer · Bischofswerda, DE

Key dates

• Filing date: Aug 2, 1978
• Grant date: Dec 11, 1979
• Expiry date: Aug 2, 1998

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C273/189
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for the manufacture of symmetrical dialkylureas by reacting monoalkylamines with CO.sub.2 at an elevated temperature and under superatmospheric pressure, in which the unconverted starting materials, water and the by-products formed in the reaction zone, as well as alkylamine alkylcarbamate, after thermal decomposition into monoalkylamine, CO.sub.2 and water, are separated from the dialkylurea formed, and thereafter a part of the unconverted starting materials plus by-products, with or without water, may or may not be recycled to the reaction zone, before isolating an aqueous solution, containing monoalkylamines, CO.sub.2 and other by-products, which solution is treated with alkali metal hydroxide solution in a column, the monoalkylamine, after separation from carbon dioxide and water, being recycled to the reaction zone. The dialkylureas obtained contain not more than 1% of monoalkylurea and 1% of trialkylurea, and may be used as starting materials for various syntheses.