Granted Patent
Utility
US 5,347,021 · App. 07/656,388
Process of vapor phase catalytic hydrogenation of maleic anhydride to gamma-butyrolactone in high conversion and high selectivity using an activated catalyst
Inventors:
Paul D. Taylor, Waldo De Thomas, Donald W. Buchanan, Jr.
Patented Case
View Patent ↗
Granted: Sep 13, 1994
Filed: Feb 19, 1991
Inventors
Paul D. Taylor
Waldo De Thomas
Donald W. Buchanan, Jr.
Assignee (at issue)
ISP INVESTMENTS LLC
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.