Granted Patent
Utility
US 5,340,446 · App. 07/966,001
Purification of propylene oxide by cosolvent extractive distillation
Inventors:
William P. Nelson, William A. Smith
Patented Case
View Patent ↗
Granted: Aug 23, 1994
Filed: Oct 23, 1992
Inventors
William P. Nelson
William A. Smith
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.