The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 07, 1994
Filed:
Aug. 05, 1992
Applicant:
Inventors:
Gunter Roscher, Kelkheim, DE;
Hans-Jerg Kleiner, Kronberg/Taunus, DE;
Harald Berger, Kelkheim, DE;
Manfred Schmidt, Kelkheim, DE;
Rainer Uhmann, Kriftel/Taunus, DE;
Dirk Bottger, Hunstetten, DE;
Assignee:
Hoechst Aktiengesellschaft, Frankfurt, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07F / ;
U.S. Cl.
CPC ...
562878 ;
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.