Process for preparing di-C.sub.1 - C.sub.4 -alkyl 5-nitro-isophthalates

US6002041A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Gunter Rauchschwalbe · Leverkusen, DE
• Bernhard Beitzke · Bensberg, DE
• Helmut Fiege · Leverkusen, DE

Key dates

• Filing date: May 6, 1998
• Grant date: Dec 14, 1999
• Expiry date: May 6, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C201/12
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Particularly pure di-C.sub.1 -C.sub.4 -alkyl 5-nitro-isophthalates are obtained in good yield and in a simple process by dissolving 5-nitro-isophthalic acid in a mixture of a C.sub.1 -C.sub.4 -alkyl alcohol and a solvent which is miscible or only partially miscible with water, heating in the presence of a strong acid, thus forming a second, aqueous phase, crystallizing out, after the esterification reaction has ended, the di-C.sub.1 -C.sub.4 -alkyl 5-nitro-isophthalate formed from the organic phase by cooling and removing the aqueous phase before or after the di-C.sub.1 -C.sub.4 -alkyl 5-nitro-isophthalate is separated off.