Energy efficient process of preparing triaryl phosphates

Abstract

In a process of preparing triaryl phosphates by direct esterification which comprises A. Reaction Steps: The steps of (a) Reacting a hydroxyaryl with phosphoric acid or equivalent to form an aryl phosphate and water (b) Removing the water by entrainment by means of hydroxyaryl vapor, and (c) Condensing the water-containing entraining vapor, and B. Dehydration Step: The step of separating the water from the water-containing entraining vapor by distillation, and C. Recycling Steps: The steps of (a) Evaporating the dry hydroxyaryl liquid and (b) Using its vapor as the entraining vapor in step (A, b). the improvement which comprises I. Carrying out the Reaction Steps A at essentially higher pressure than the Dehydration Step B, and II. Using all, or part of, the water-containing hydroxyaryl vapor from Step (A, b) as the heating medium in Step B.

Dependencies are inferred from the claim text.