The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 24, 2009
Filed:
Dec. 22, 2004
Eric James Pressman, East Greenbush, NY (US);
Lioba Maria Kloppenburg, Mt. Vernon, IN (US);
John Morgan Whitney, Niskayuna, NY (US);
Abhijit Namjoshi, Guilderland, NY (US);
Spencer Thomas Oulman, Texas City, TX (US);
Eric James Pressman, East Greenbush, NY (US);
Lioba Maria Kloppenburg, Mt. Vernon, IN (US);
John Morgan Whitney, Niskayuna, NY (US);
Abhijit Namjoshi, Guilderland, NY (US);
Spencer Thomas Oulman, Texas City, TX (US);
SABIC Innovative Plastics, Pittsfield, MA (US);
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.