Granted Patent
Utility
US 5,177,301 · App. 07/822,803
Method of separating isobutylene from a C-4 hydrocarbon fraction using a heteropoly acid on an inert support
Inventor:
John F. Knifton
Patented Case
View Patent ↗
Granted: Jan 5, 1993
Filed: Jan 21, 1992
Inventor
John F. Knifton
Assignee (at issue)
Texaco Chemical 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.