Granted Patent
Utility
US 4,423,253 · App. 06/372,056
Process for separating t-butylated phenols
Inventor:
Gerd Leston
Patented Case
View Patent ↗
Granted: Dec 27, 1983
Filed: Apr 26, 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.