Patent ID: 8809486
Filing Date: 2014-08-19
Classification: C07D,C08G

Abstract:
1. A method for producing a highly purified 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine of formula (I) wherein R precipitating the phthalimidine compound from the reaction mixture to provide a crude phthalimidine compound; dissolving the crude phthalimidine compound in an aqueous solution comprising an alkali metal hydroxide, an alkaline earth hydroxide, or a combination comprising at least one of the foregoing metal hydroxides; precipitating the dissolved, crude phthalimidine compound from the aqueous base solution by adding a mineral acid in an amount effective to lower the pH of the solution to 9.0 to 12.0, to provide a semicrude phthalimidine compound; and isolating the semicrude phthalimidine compound from the aqueous base solution, washing the isolated phthalimidine compound with dilute acid, then with water, and drying the washed phthalimidine compound to provide a purified phthalimidine compound of formula (I); triturating the purified phthalimidine compound of formula (I) with an aqueous C washing the triturated phthalimidine compound with aqueous alcohol, then hot water preheated to a temperature of 60 to 80° C.; and drying the washed phthalimidine compound to provide the highly purified 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine of formula (I), having a phenolphthalein compound content of less than 100 ppm, based on the weight of the 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine.