A process is provided for making halogen-substituted triaryl phosphate esters which are normally solid under ambient conditions. The process comprises reacting a halogenated phenol with phosphorus oxychloride in the presence of a magnesium chloride catalyst above the melting point of the desired product. After the reaction is complete the product is recovered by adding an alcohol, such as, pentanol, 2-ethyl hexanol or hexanol and cooling the resulting mixture below the melting point of the product.