Granted Patent
Utility
US 4,335,059 · App. 06/219,788
Preparation of carboxylic acid anhydrides
Inventor:
Nabil Rizkalla
Patented Case
View Patent ↗
Granted: Jun 15, 1982
Filed: Dec 24, 1980
Inventor
Nabil Rizkalla
Assignee (at issue)
Halcon Research and Development Corp.
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.