Granted Patent
Utility
US 4,420,644 · App. 06/295,459
Lignin hydrocracking process to produce phenol and benzene
Inventors:
Derk T. A. Huibers, Hugh J. Parkhurst, Jr.
Patented Case
View Patent ↗
Granted: Dec 13, 1983
Filed: Aug 24, 1981
Inventors
Derk T. A. Huibers
Hugh J. Parkhurst, Jr.
Assignee (at issue)
Hydrocarbon Research, 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.