Granted Patent
Utility
US 4,698,187 · App. 06/798,764
Preparation of carboxylic acid anhydrides
Inventor:
Colin Hewlett
Patented Case
View Patent ↗
Granted: Oct 6, 1987
Filed: Nov 15, 1985
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.