Patent ID: 6613928
Filing Date: 2003-09-02
Classification: C07F

Abstract:
A process for preparing a condensed phosphoric ester, comprising:a first step of reacting a bisphenol A derivative with a phosphorus oxytrihalide in an amount equal to or greater than 4.5 mol times the amount of the bisphenol A derivative to prepare a phosphorohalidate; wherein the bisphenol A derivative is of the formula: â€ƒwhere R5 and R6 are the same as or different from each other and represent an alkyl group containing 1 to 3 carbon atoms, and n1 and n2 each represent an integer from 0 to 4 a second step of removing unreacted phosphorus oxytrihalide after the first step; a third step of reacting the phosphorohalidate obtained in the second step with a monophenol-based compound at a temperature equal to or lower than 120Â° C., and a fourth step of reacting the product obtained in the third step with the monophenol-based compound used in the third step at a temperature equal to or higher than 120Â° C.