Reaction of Triphenylphosphine with Poly(ethylene terephthalate) and Certain Model Compounds at Elevated Temperature

Triphenylphosphine and poly(ethylene terephthalate) react at 370°C to produce ethylene, triphenylphosphine oxide, carbon dioxide, benzoic acid, and terephthalic acid. The reaction proceeds by the initial formation of a zwitterionic species which then generates a phosphonium ylid and leads to the observed products. Any flame retardant activity from the use of triphenyl‐phosphine may be attributed to the formation of triphenylphosphine oxide. The co‐production of ethylene renders triphenylphosphine a less effective flame retardant than triphenylphosphine oxide