Granted Patent
Utility
US 4,731,491 · App. 06/821,190
Process for liquefaction of lignin
Inventors:
Peter Urban, Dusan J. Engel
Patented Case
View Patent ↗
Granted: Mar 15, 1988
Filed: Jan 22, 1986
Inventors
Peter Urban
Dusan J. Engel
Assignee (at issue)
UOP 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.