The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 31, 1992
Filed:
Feb. 22, 1991
Applicant:
Inventors:
Francisco J Freire, Wilmington, DE (US);
Jon L Howell, Bear, DE (US);
Kaye L Motz, Ponca City, OK (US);
Craig T Barker, Ponca City, OK (US);
William C Ziegenhain, Ponca City, OK (US);
Eileen G Edwards, Ponca City, OK (US);
Assignee:
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C01B / ; C02F / ; C25B / ;
U.S. Cl.
CPC ...
423484 ; 204101 ; 204128 ; 204186 ; 210748 ; 210758 ;
Abstract
A process for manufacturing high purity anhydrous hydrogen fluoride (HF) having low levels of oxidizable impurities by electrolytically oxidizing the impurities. Specifically, trivalent arsenic impurity in the anhydrous hydrogen fluoride is oxidized to a non-volatile pentavalent arsenic compound. The resultant mixture is distilled to recover high purity anhydrous hydrogen fluoride with low levels of arsenic impurity.