Method of purifying dianhydrides

US7495113B2 · kind B2 · utility

Assignee

• Sabic Innovative Plastics B.V. · NL

Inventors

• Eric James Pressman · East Greenbush, US
• Lioba Maria Kloppenburg · Mount Vernon, US
• John Morgan Whitney · Schenectady, US
• Abhijit Namjoshi · Midland, US
• Spencer Thomas Oulman · Wijkermeerstraat, US

Key dates

• Filing date: Dec 22, 2004
• Grant date: Feb 24, 2009
• Expiry date: Jun 20, 2026

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/573
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A method of preparing a purified dianhydride is provided where said method comprises the steps of preparing a first mixture comprising water, at least one inorganic acid, and at least one dianhydride, said dianhydride comprising at least one impurity which is soluble in aqueous acid heating said first mixture until substantially all of said dianhydride is converted to a tetraacid comprised in a second mixture; filtering at least a portion of said second mixture to provide a solid tetraacid and a filtrate, said filtrate comprising at least a portion of said impurity; and heating the tetraacid provided in a solvent with concurrent distillation of water to provide a third mixture comprising a purified dianhydride and a solvent.