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:
Sep. 07, 2010
Filed:
Sep. 04, 2007
Balakrishnan Ganesan, Bangalore, IN;
Pradeep Jeevaji Nadkarni, Bangalore, IN;
Kumar Arun Satyanarayana, Karnataka, IN;
Venkata Rama Narayanan Ganapathy Bhotla, Karnataka, IN;
Suresh Shanumgam, Bangalore, IN;
Gurram Kishan, Bangalore, IN;
Ravindra Vikram Singh, Basti, IN;
Balakrishnan Ganesan, Bangalore, IN;
Pradeep Jeevaji Nadkarni, Bangalore, IN;
Kumar Arun Satyanarayana, Karnataka, IN;
Venkata Rama Narayanan Ganapathy Bhotla, Karnataka, IN;
Suresh Shanumgam, Bangalore, IN;
Gurram Kishan, Bangalore, IN;
Ravindra Vikram Singh, Basti, IN;
Abstract
A method for purifying a 2-aryl-3,3-bis(hydroxyaryl)phthalimidine comprises contacting a crude 2-aryl-3,3-bis(hydroxyaryl)phthalimidine with a purification agent, removing a 2-aryl-3-(aminoaryl)-3-(hydroxyaryl)phthalimidine compound from the crude 2-aryl-3,3-bis(hydroxyaryl)phthalimidine, and producing a purified 2-aryl-3,3-bis(hydroxyaryl)phthalimidine product comprising less than 200 parts per million of the 2-aryl-3-(aminoaryl)-3-(hydroxyaryl)phthalimidine compound. The purification agent is selected from the group consisting of an acidic material, an organic acid chloride, an organic anhydride, or a combination thereof. The 2-aryl-3-(aminoaryl)-3-(hydroxyaryl)phthalimidine compound has a formula: wherein each Ris independently selected from a group consisting of a hydrocarbyl radical, a nitro radical, and a halogen atom; 'a' is an integer from 0 to 4; and Arand Arare independently at each occurrence an aromatic radical. The purified 2-aryl-3,3-bis(hydroxyaryl)phthalimidines have low color, and are useful for preparing polymers, such as polycarbonates having a low color. The polycarbonates are useful for producing articles.