Process for the preparation of pure propanephosphonic anhydride

US5319138A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Gunter Roscher · Kelkheim, DE
• Hans-Jerg Kleiner · Kronberg, DE
• Harald Berger · Kelkheim, DE
• Manfred Schmidt · Krefeld, DE
• Rainer Uhmann · Kriftel, DE
• Dirk Bottger · Liederbach, DE

Key dates

• Filing date: Aug 5, 1992
• Grant date: Jun 7, 1994
• Expiry date: Aug 5, 2012

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07F9/3895
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Process for the preparation of pure propanephosphonic anhydride, which comprises distilling crude, impure propanephosphonic anhydride having an average degree of polymerization of 20 to 200 and containing less than 0.5% by weight of water by heating to 230 to 300.degree. C. under a pressure of 0.1 to 100 mbar, pure propanephosphonic anhydride having an average degree of polymerization of 20 to 60 being obtained.