Process for the purification of 2-hydroxynaphthalene-6-carboxylic acid

US4916257A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Helmold von Plessen · Kelkheim, DE
• Siegbert Rittner · Mörfelden, DE
• Heinrich Volk · Beerfelden, DE
• Werner Wykypiel · Rodgau, DE
• Rudolf Neeb · Offenbach am Main, DE

Key dates

• Filing date: Jan 12, 1989
• Grant date: Apr 10, 1990
• Expiry date: Jan 12, 2009

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/43
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to a process for purification of 2-hydroxynaphthalene-6-carboxylic acid by recrystallization. In this process, the crude acid is recrystallized from water-miscible linear or cyclic aliphatic ethers, aliphatic polyethers or aliphatic hydroxy ethers or from at least 10% strength by weight aqueous solutions of these ethers. Recrystallization from a 35-90% strength by weight aqueous solutions of 1,4-dioxane is particularly preferred.