Process for separating propylene glycol from aqueous compositions

US8197645B2 · kind B2 · utility

Assignees

• BASF SE
• THE DOW CHEMICAL COMPANY · US

Inventors

• Armin Diefenbacher · Germersheim, DE
• Hans-Georg Goebbel · Kallstadt, DE
• Stefan Bitterlich · Dirmstein, DE
• Hartwig Voss · Bischofswerda, DE
• Henning Schultz · Mannheim, DE
• Anna Forlin · Vigonza, IT
• Renate Patrascu · Stade, DE

Key dates

• Filing date: Dec 13, 2006
• Grant date: Jun 12, 2012
• Expiry date: Jun 5, 2029

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S203/17
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

The present invention relates to a process for separating at least one propylene glycol from a mixture (M) comprising water and said propylene glycol, said process comprising (I) evaporating the mixture in at least two evaporation and/or distillation stages at decreasing operating pressures of the evaporators and/or distillation columns obtaining mixture (M′) and mixture (M″); (II) separating the mixture (M′) obtained in (I) in at least one further distillation step, obtaining a mixture (M-I) comprising at least 70 wt.-% of water and a mixture (M-II) comprising less than 30 wt.-% of water.