Method of purifying dianhydrides, the dianhydrides formed thereby, and polyetherimides formed therefrom

US8013173B2 · kind B2 · utility

Assignee

• Sabic Innovative Plastics B.V. · NL

Inventors

• Beatriz Penalver Bernabe · Chicago, US
• Vijay Gopalakrishnan · Edison, US
• Lioba Maria Kloppenburg · Mount Vernon, US
• Matt Kuhlman · Evansville, US
• Roy Ray Odle · Greenwood, US
• Eric James Pressman · East Greenbush, US
• Narayan Ramesh · Niskayuna, US
• Harpreet Singh · Evansville, US

Key dates

• Filing date: Mar 28, 2008
• Grant date: Sep 6, 2011
• Expiry date: Apr 18, 2028

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G73/1053
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A method for purifying an oxydiphthalic anhydride comprises diluting a first mixture comprising an oxydiphthalic anhydride, a solvent, a catalyst, and an inorganic salt with a solvent, to provide a second mixture having a solids content of 10 to 30 percent based on total weight of the second mixture; filtering and washing the solids of the second mixture at a temperature below the crystallization point temperature of the oxydiphthalic anhydride to provide a third mixture; hydrolyzing the third mixture by adding water and a water-soluble acid to form a fourth mixture; heating the fourth mixture; then cooling to provide a solid-liquid mixture, optionally decanting a portion of the liquid, rediluting the remaining solid-liquid mixture, then filtering to provide a solid component; washing the solid component with water to provide a fifth mixture of oxydiphthalic tetraacid and water; ring closing the oxydiphthalic tetraacid to provide oxydiphthalic anhydride, and filtering the oxydiphthalic anhydride.