Patent · US Expired

Method for preparation of 4-halogenonaphthalic acid anhydrides

US4582910A · kind A · utility

2Cited by

3References

22Claims

0Family size

Assignee

Rutgerswerke Aktiengesellschaft · DE

Inventors

Winfried Orth
Emmerich Pastorek · Hemsbach, DE
Werner Fickert · Mannheim, DE

Key dates

Filing date	Feb 19, 1985
Grant date	Apr 15, 1986
Priority date	—
Expiry date	Feb 19, 2005

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC07C51/363
WIPO fieldOrganic fine chemistry
WIPO sectorChemistry

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.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.