Process for the production of dianhydrohexitol mixtures and the production of polymers from such mixtures

US4564645A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Herbert Salzburg · Leichlingen, DE
• Manfred Hajek · Leverkusen, DE
• Holger Meyborg · Odenthal, DE

Key dates

• Filing date: Jan 7, 1985
• Grant date: Jan 14, 1986
• Expiry date: Jan 7, 2005

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G18/3218
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Liquid dianhydrohexitol mixtures are prepared from diacylation products of hexitols and compounds such as organic carboxylic acids, carboxylic acid anhydrides, carboxylic acid halides, ketene and carbonic acid ester derivatives. More specifically, such diacylation products are simultaneously dehydrated and isomerized by subjecting them to a temperature of at least 130.degree. C. in the presence of a strong acid to yield diacylated dianhydro-hexitol isomer mixtures. These isomer mixtures are then converted to dianhydro-hexitol isomer mixtures by hydrolysis or transesterification. Suitable strong acids include proton acids, Lewis acids and heterogeneous acid catalysts (e.g., ion exchange resins). The mixtures of the present invention are characterized by a minimal tendency towards crystallization. These mixtures are particularly useful as chain extending agents in the production of polyurethanes.