Granted Patent
Utility
US 4,584,399 · App. 06/675,368
Purification of L-phenylalanine
Inventors:
Charles Portal, James F. Walter
Patented Case
View Patent ↗
Granted: Apr 22, 1986
Filed: Nov 27, 1984
Inventors
Charles Portal
James F. Walter
Assignee (at issue)
W. R. Grace & Co.
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.