Commercial production is by direct oxidation of phosphorus trichloride with oxygen.
About 75 to 80 percent of POCl3 production is estimated to be used captively in the manufacture of phosphate esters for plasticizers, flame retardants, hydraulic fluids and other applications. FMC sold its process additives business, including phosphorus oxychloride and trichloride plants in Nitro, W.Va., to Great Lakes Chemical Corporation in mid-1999. The sale also included phosphate esters, flame retardant fluids, lubricant additives and specialty water treatment chemicals. The demand for plastics additives, which account for more than half of phosphorus oxychloride's market, continues to expand, and functional fluids are an additional growth segment. In downstream markets, engineering plastics for computer and electronic applications enjoyed sustained growth in the 1990s, strengthening the consumption of phosphorus-based ester additives.