Granted Patent
Utility
US 4,987,238 · App. 07/395,971
Process for the preparation of high-purity 5,5'-[2,2,2-trifluoro-1-(trifluoromethyl)-ethylidene]bis-1,3-isobenzofur andione
Inventor:
Freimund Rohrscheid
Patented Case
View Patent ↗
Granted: Jan 22, 1991
Filed: Aug 2, 1989
Inventor
Freimund Rohrscheid
Assignee (at issue)
Hoechst GmbH
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.