Granted Patent
Utility
US 4,284,797 · App. 06/044,122
Process for separating mixtures of 3- and 4-nitrophthalic acid
Inventors:
Peter Furrer, Harry Beyeler
Patented Case
View Patent ↗
Granted: Aug 18, 1981
Filed: May 31, 1979
Inventors
Peter Furrer
Harry Beyeler
Assignee (at issue)
Ciba-Geigy
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.