Method for isolation of a dianhydride and dianhydrides prepared by the method

US11661416B2 · kind B2 · utility

Assignee

• SHPP Global Technologies B.V. · NL

Inventors

• Aaron Royer · McCarty, US
• Sivakumar Periyasamy · Savanuru, IN
• Ravi Gautam · Plano, US
• Jorge Jimenez Umana · Sugar Land, US
• Gregory L. Hemmer · Amber, US
• Robert Werling · Evansville, US
• Hareesh Shamrao Deshpande · Kanchinakote, IN

Key dates

• Filing date: May 13, 2019
• Grant date: May 30, 2023
• Expiry date: Nov 20, 2039

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D407/12
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A method for producing an aromatic dianhydride includes reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent in a first extractor for a first time period, at a first extraction temperature and subsequent to the first time period, extracting the aqueous reaction mixture with an organic solvent in a second extractor for a second time period, at a second extraction temperature. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.