Process for extracting N-methyl-2-pyrrolidone

US5068358A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Georg-Emerich Miess · Regensburg, DE
• Karl-Heinz Schwarz · Rincón de la Victoria, ES
• Heribert Tetzlaff · Frankfurt am Main, DE
• Bernhard Wojtech · Bad Soden am Taunus, DE

Key dates

• Filing date: Oct 11, 1989
• Grant date: Nov 26, 1991
• Expiry date: Oct 11, 2009

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D207/38
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to a process for separating N-methyl-2-pyrrolidone (NMP) from aqueous solutions which are obtained in industry, inter alia, in the production of heat-resistance polymers such as polyamides and polyimides. According to the invention, the extractants used are phenols which are sparingly soluble in water, are aliphatically monosubstituted and/or polysubstituted in the nucleus and have 4 to 16 carbon atoms in the straight-chain or branched, saturated or unsaturated aliphatic radical and have a boiling point which is preferably at least 20.degree.-25.degree. C. above the boiling point of NMP. If necessary, an inert, viscosity-reducing diluent is added.