Granted Patent
Utility
US 4,447,654 · App. 06/431,640
Process for separating nitrated phenolic compounds from other phenolic compounds
Inventor:
Gerd Leston
Patented Case
View Patent ↗
Granted: May 8, 1984
Filed: Sep 30, 1982
Inventor
Gerd Leston
Assignee (at issue)
KOPPERS, INC.
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.