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:
Jun. 09, 1998
Filed:
Dec. 20, 1996
Applicant:
Inventors:
Albert-Johannes Frings, Rheinfelden, DE;
Michael Horn, Rheinfelden, DE;
Peter Jenker, Rheinfelden, DE;
Jaroslaw Monkiewicz, Rheinfelden, DE;
Hans-Guenther Srebny, Duelmen, DE;
Burkhard Standke, Loerrach, DE;
Bertram Trautvetter, Rheinfelden, DE;
Assignee:
Huels Aktiengesellschaft, Marl, DE;
Primary Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
564434 ; 564437 ;
Abstract
A process for the purification of crude N,N'-diphenyl-p-phenylenediamine (DPPD), which comprises extracting crude DPPD with a hydrocarbon or hydrocarbon mixtures thereby forming an extract solution containing DPPD, passing the extract solution over an adsorption layer, and recovering purified DPPD from the solution.