Granted Patent
Utility
US 5,384,413 · App. 08/090,794
Process for the preparation of tetrafluorophthalic acid and/or tetrafluorophthalic anhydride
Inventors:
Ralf Pfirmann, Theodor Papenfuhs
Patented Case
View Patent ↗
Granted: Jan 24, 1995
Filed: Jul 12, 1993
Inventors
Ralf Pfirmann
Theodor Papenfuhs
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.