Production of phosphorus oxyhalide

Improvement in the oxygen oxidation of phosphorus trihalides, particularly phosphorus trichloride, to phosphorus oxyhalide, particularly oxychloride, by introducing phosphorus trihalide and gaseous oxygen into the bottom of an elongated, substantially vertical reaction zone, passing said phosphorus trihalide and oxygen upwardly through said zone while reacting such together; withdrawing a portion of the upwardly flowing reaction mixture from an intermediate point in said zone; introducing oxygen into admixture with said withdrawn admixture and cooling, agitating and reacting such; returning said admixture reaction mass to said elongated reaction zone; and recovering substantially pure phosphorus oxyhalide from the downstream end of said reaction zone.