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:
Jan. 01, 1980
Filed:
Mar. 06, 1979
Applicant:
Inventor:
Josef Landler, Hofheim am Taunus, DE;
Assignee:
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C07D / ;
U.S. Cl.
CPC ...
548328 ;
Abstract
The pure sodium hydroxide addition products of the cis-isomers of naphthoylene-bis-benzimidazoles are recovered from their alkaline aqueous-alcoholic solution as obtained in their synthesis by eliminating the alcohol as far as feasible, reacting the remaining aqueous alkaline solution with chlorine or sodium hypochlorite solution at an elevated temperature, removing the insoluble by-products, introducing into the hot solution a compound yielding sodium ions and isolating the precipitating product or processing it further to yield the free naphthoylene-bis-benzimidazole pigments.