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. 14, 1992
Filed:
Oct. 10, 1990
Heinz U Blank, Odenthal, DE;
Edwin Ritzer, Burscheid, DE;
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
Substituted 3,5-dichloro-2,4-difluoro-benzenes of the formula ##STR1## in which R represents nitro, amino (including the corresponding ammonium salts) or isocyanato, which can be prepared from 2,3,4,5-tetrachloro-nitrobenzene by means of the reaction, carried out initially, with alkali metal fluorides at elevated temperature in a polar, aprotic solvent, starting from a crude 2,3,4,5-tetrachloro-nitrobenzene containing 2,3,5,6-tetrachloro-nitrobenzene and/or 2,3,4,6-tetrachloro-nitrobenzene, and substituted 3,5-dichloro-2,4-difluoro-benzene being isolated from the reaction mixture at the nitro stage or, after reduction of the nitro group, at the amino stage or, after reduction and phosgenation of the amino group, at the isocyanate stage.