Preparation of N‐alkenyl‐ and N‐m‐styryl‐phosphoramidates and their application as flame retardants for wood

Interaction of organophosphorus halides with allylamine and diallylamine yields N‐alkenyl‐phosphoramidates: with m‐aminostyrene, N‐m‐styryl derivatives are obtained. These compounds may be polymerised with varying degrees of facility by heat, free‐radical or ammonium persulphate initiation to yield resins or gums. The preparation and properties of phosphoramidate monomers obtained by condensation of these unsaturated amines with mono‐ and bifunctional phosphoro‐, phosphono‐ and phosphonothio‐chloridates is described. The attempted condensation of phosphoramidates with αβ‐unsaturated acid chlorides to obtain N‐unsaturated acyl phosphoramidates gave syrups which resinified on heating to yield brittle solids high in phosphorus and nitrogen. Some of the compounds described have been used to impregnate wood blocks, and polymerised in situ, either by heat, chemical or irradiation initiation, and they imparted flame‐retardant properties to the wood which were resistant to cold‐water leaching.