Granted Patent
Utility
US 4,499,312 · App. 06/582,082
Complex formed to separate 3,5-xylenol or 3,4-xylenol from other polymethylated phenolic compounds
Inventor:
Gerd Leston
Patented Case
View Patent ↗
Granted: Feb 12, 1985
Filed: Feb 21, 1984
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.