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:
Apr. 15, 1986
Filed:
Feb. 19, 1985
Applicant:
Inventors:
Assignee:
Rutgerswerke Aktiengesellschaft, Frankfurt, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C07D / ;
U.S. Cl.
CPC ...
549232 ;
Abstract
A method for the preparation of 4-halogenonaphthalic acid anhydrides by halogenation of an aqueous solution of an alkali salt of the naphthalic acid with halogen or alkali metal hypohalogenite wherein a solution of the alkali metal salt of the naphthalic acid is treated with a water soluble magnesium salt and at least an equal molar amount of an alkakli metal hydroxide, halogenating this reaction mixture at a temperature in the range of 10.degree. to 25.degree. C. and subsequently acidifying the reaction mixture. In a second embodiment of the invention, an aqueous solution of alkali metal carbonate is used in place of the magnesium salt and alkali metal hydroxide.