Abstract: Crude phosphate ester products resulting from the phosphorylation of phenol, lower alkyl phenols and mixtures of same are purified to prepare triaryl phosphates substantially free of unreacted phenols by the sequential steps of flash distillation and fractional distillation under controlled conditions with removal of the phosphate ester product as a liquid underflow.

Abstract: A method for control of the steam flashing of poly(arylene sulfide) reaction product to remove substantially all of the reaction diluent from a reaction mixture containing poly(arylene sulfide) polymer, organic polar diluent, byproduct alkali metal halide, and reaction mixture impurities is provided by measuring the vapor effluent from the flashing operation, producing a signal representative of this flow, controlling the rate of flow of the effluent from the reactor in response to this signal, and controlling the rate of flow of steam admixed with the reactor effluent in ratio to the effluent flow.