Method for preparation 3-(hydroxyphenylphosphinyl)-propanoic acid

摘要

Disclosed is a method for the preparation of 3-(hydroxyphenylphosphinyl)-propanoic acid which is commonly used as a flame retardant for polyester resins. The preparation of 3-(hydroxyphenylphosphinyl)-propanoic acid is attained by the condensation of phenylphosphonous dichloride and acrylic acid and the hydrolysis of the condensate. In the condensation, the mole ratio of phenylphosphonous dichloride to acrylic acid is within the range of 1:1.1 to 1:1.25. Under a pressure of greater than 1 atm, acrylic acid is added at 65 DIFFERENCE 110 DEG C. at an amount more by 10 DIFFERENCE 25 mole % than that of phenylphosphonous dichloride and the condensation is carried out at a temperature of 70 DIFFERENCE 100 DEG C. under at greater than 1 atm, to produce 3-(hydroxyphenylphosphinyl)-propanoic acid at high yields with desired color.