Phosphene (PH3) is a dangerous tail-gas, generated in significant quantities in certain phosphorus chemical industry processes. To avoid risk, it is converted to THPS (tetrakis (hydroxmethyl)phosphonium sulphate). China produces c. 50 000 t/y THPS, but only around one fifth is sold for industry applications, so that PIN flame retardant production from THPS enables phosphorus recycling.
Two different P-containing amines were combined with THPS in a three step process to generate P-benzoxazine polymers (TBOz and BBOz). These show very high char formation capacity, and so interesting potential as phosphorus PIN FRs, with possible economic and environmental advantages because based on industrial by-products.
“Phosphorus-containing polymers from THPS. IV: Synthesis andproperties of phosphorus-containing polybenzoxazines as a greenroute for recycling toxic phosphine (PH3) tail gas”, Z-W Tan et al., J. Hazardous Materials 2016 (in print) http://dx.doi.org/10.1016/j.jhazmat.2016.10.021