Granted Patent
Utility
US 4,792,420 · App. 06/758,632
Purification of carboxylic acid anhydrides
Inventor:
Nabil Rizkalla
Patented Case
View Patent ↗
Granted: Dec 20, 1988
Filed: Jul 24, 1985
Inventor
Nabil Rizkalla
Assignee (at issue)
EASTMAN KODAK COMPANY
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.