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:
May. 04, 2004
Filed:
Nov. 27, 2001
Applicant:
Inventors:
Ralf Bertram, Holzminden, DE;
Stephan Hillers, Holzminden, DE;
Oskar Koch, Göttingen, DE;
Harry Erfurt, Uslar, DE;
Gerald Reinders, Salzkotten, DE;
Assignee:
Symrise GmbH & Co. KG, , DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07D / ; C07C / ;
U.S. Cl.
CPC ...
C07D / ; C07C / ;
Abstract
Phenylene-bis-benzimidazole-tetrasulfonic acid disodium salt which is largely free from impurities can be prepared by reacting o-phenylenediamine with terephthalic acid and chlorosulfonic acid in the presence of strong acids with a reaction time of 10 to 15 hours.