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:
Oct. 05, 2010
Filed:
Dec. 13, 2007
Bernhard Dung, Mannheim, DE;
Felix Mueller, Frankenthal, DE;
Arno Boehm, Mannheim, DE;
Willi Helfer, Friedelsheim, DE;
Volker Weyrauch, Deidesheim, DE;
Georg Henning, Ludwigshafen, DE;
Bernhard Dung, Mannheim, DE;
Felix Mueller, Frankenthal, DE;
Arno Boehm, Mannheim, DE;
Willi Helfer, Friedelsheim, DE;
Volker Weyrauch, Deidesheim, DE;
Georg Henning, Ludwigshafen, DE;
BASF Aktiengesellschaft, Ludwigshafen, DE;
Abstract
A process for preparing perylene-3,4:9,10-tetracarboxylic dianhydride, comprising: dimerizing a naphthalene-1,8-dicarboximide of the formula IIa; reoxidizing the resulting alkali metal salt of the leuco form of the perylene-3,4:9,10-tetracarboxylic diimide of the formula Ia; hydrolyzing the diimide to the tetraalkali metal salt of perylene-3,4:9,10-tetracarboxylic acid in the presence of an inert organic solvent, of an alkali metal base and of water; and subjecting the tetraalkali metal salt of perylene-3,4:9,10-tetracarboxylic acid to the action of an aqueous inorganic acid to convert it into perylene-3,4:9,10-tetracarboxylic dianhydride; wherein Ris cyclohexyl or phenyl which may each be substituted by up to three C-C-alkyl radicals, and the dimerizing is in a substantially homogeneous reaction medium consisting essentially of an apolar aprotic organic solvent and an alkali metal base.