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:
Aug. 12, 1986
Filed:
May. 16, 1985
Otto Arndt, Hofheim am Taunus, DE;
Theodor Papenfuhs, Frankfurt am Main, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
Process for the preparation of 2,6-dichloro-4-nitroaniline by chlorination of 4-nitroaniline with chlorine bleaching liquor in water using acids, which comprises chlorinating 1 mole of 4-nitroaniline in 3-6 moles of hydrochloric acid (HCl) or nitric acid (HNO.sub.3) in the form of a dilute, aqueous acid in the presence of a dispersing agent which is stable under the reaction conditions, the chlorination initially being carried out at 5.degree. to 10.degree. C. and then at 15.degree.-20.degree. C. and, finally, after 90-95% of the 2-chloro-4-nitroaniline intermediately formed has been converted into 2,6-dichloro-4-nitroaniline, the temperature of the aqueous suspension being increased from 15.degree.-20.degree. C. to 70.degree. C., without further addition of chlorine bleaching liquor, and then by post-chlorinating, by renewed addition of chlorine bleaching liquor, at temperatures between 20.degree. and 70.degree. C., bringing the pH of the aqueous suspension to 9.0 and filtering off the 2,6-dichloro-4-nitroaniline formed and washing it with dilute mineral acid.