Methods for producing and purifying 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine compounds, the purified monomers, and polymers derived therefrom
View Patent ↗Disclosed herein is a method for producing a purified 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine of formula (I) wherein R 1 is hydrogen or a C 1-25 hydrocarbyl group and R 2 is a hydrogen, a C 1-25 hydrocarbyl group, or a halogen, and wherein the method comprises dissolving a crude phthalimidine compound in an aqueous base solution; precipitating the dissolved, crude phthalimidine compound from the aqueous base solution by adding an 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, to provide the purified 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine of formula (I), and having a phenolphthalein compound content of less than 2,500 ppm, based on the weight of the purified 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine. Subsequent trituration with aqueous methanol and recrystallization from isopropanol can result in product having levels of phenolphthalein derivatives that are not detectable.
1. A method for producing a purified 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine of formula (I)
wherein R 1 is hydrogen or a C 1-25 hydrocarbyl group and R 2 is hydrogen, a C 1-25 hydrocarbyl group, or a halogen, and wherein the method comprises:
heating a reaction mixture comprising
a phenolphthalein compound of formula (II)
wherein R 2 is hydrogen, a C 1-25 hydrocarbyl group, or a halogen,
a primary aryl amine of formula (III),
wherein R 1 is hydrogen or a C 1-25 hydrocarbyl group, and
an acid catalyst, to form a phthalimidine compound of formula (I);
precipitating the phthalimidine compound from the reaction mixture to provide a crude phthalimidine compound;
dissolving the crude phthalimidine compound in an aqueous base solution;
precipitating the dissolved, crude phthalimidine compound from the aqueous base solution by adding an acid in an amount effective to lower the pH of the solution to 1.0 to less than 9.0, to provide a semicrude phthalimidine compound;
isolating the semicrude phthalimidine compound from the aqueous base solution, to provide the 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine of formula (I); and
sequentially triturating the purified phthalimidine of formula (I) at least twice with an aqueous methanol solution to provide a highly purified 2-aryl-3,3-bis(4-hydroxyaryl) phthalimidine of formula (I), having a phenolphthalein compound content of less than 200 ppm, based on the weight of the 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine.
2. A highly purified 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine produced by the method of claim 1 .
3. A 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine of formula (I)
wherein R 1 is hydrogen or a C 1-25 hydrocarbyl group and R 2 is hydrogen, a C 1-25 hydrocarbyl group, or a halogen, and comprising 200 ppm or less of a phenolphthalein compound of formula (II)
wherein R 2 is hydrogen, a C 1-25 hydrocarbyl group, or a halogen.
4. The 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine of claim 3 , comprising 100 ppm or less of a phenolphthalein compound of formula (II).
5. The 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine of claim 3 , comprising 50 ppm or less of a phenolphthalein compound of formula (II).
6. A polymer comprising structural units derived from the 2-aryl-3,3-bis(4-hydroxyaryl) phthalimidine of claim 3 .
7. A polymer comprising structural units derived from 2-aryl-3,3-bis(4-hydroxyaryl) phthalimidine compound of claim 4 .
8. A polymer comprising structural units derived from 2-aryl-3,3-bis(4-hydroxyaryl) phthalimidine compound of claim 5 .
9. The polymer of claim 8 , wherein the polymer is a polycarbonate copolymer comprising units derived from the 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine compound of claim 5 and units derived from bisphenol A.