Granted Patent
Utility
US 6,489,517 · App. 09/994,098
Process for preparing 3,3′,6,6′-tetraalkyl-2,2′-biphenols and 3,3′,6,6′-tetraalkyl-5,5′-dihalo-2,2′-biphenols
Inventor:
Rafael Shapiro
Patented Case
View Patent ↗
Granted: Dec 3, 2002
Filed: Nov 26, 2001
Inventor
Rafael Shapiro
Assignee (at issue)
E.I. DU PONT DE NEMOURS AND COMPANY
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.