Granted Patent
Utility
US 4,559,183 · App. 06/644,294
Preparation of carboxylic acid anhydrides
Inventor:
Colin Hewlett
Patented Case
View Patent ↗
Granted: Dec 17, 1985
Filed: Aug 27, 1984
Inventor
Colin Hewlett
Assignee (at issue)
The Halcon SD Group, 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.