Thermal oxidative degradation studies of phosphate esters

Five phosphate esters - tri-p-tolyl phosphate, tributyl phosphate, tris(1,3-dichloro-2-propyl)phosphate, tris(2,3-dibromopropyl)phosphate, and tris(2-chloroethyl)phosphate- were subjected to thermal oxidative degradation in air at 370 degrees C. Degradation mechanisms were postulated and the toxic hazards assessed based on the volatiles produced. Tri-p-tolyl phosphate was found to undergo only minimal degradation; the other compounds were decomposed extensively. Butene was the main product formed on tributyl phosphate decomposition; hydrogen halides and halogenated C2- and C3- species were the main products formed by the halogenated phosphate ester. In the case of tris(1,3-dichloro-2-propyl)phosphate acrolein, not hydrogen chloride, presented the major toxic hazard.