Process for preparing aryldiphosphate esters

摘要

A process is provided for preparing an aryl diphosphate ester containing less than 5% by weight of triarylphosphate. The process reacts a solution of a dihydroxy aromatic compound and an excess of phosphorus oxychloride in a nonaqueous solvent having a boiling point greater than 110 degrees C. The excess phosphorus oxychloride and part of the solvent are distilled from the solution at atmospheric pressure and the intermediate, a diphosphotetrachloridate solution, is reacted with a monohydric aryl compound. After extracting with an aqueous, alkaline solution the product is recovered by distilling off the remaining solvent.