Synthesis Of Oligomeric Organophosphonate Flame Retardants

With the strengthening of people’s environmental protection consciousness, flame retardant studies have entered into the new stage:low toxicity, smoke suppression, resistance to melt, environmental protection, and high efficiency will be the future development direction of flame retardants.Oligomeric organic phosphonate flame retardant is consistent with this flame retardant requirements. In this paper, four halogen-free flame retardants such as tetramethy1,4-phenylenebis(methylene)diphosphonate, tetrethy1,4-phenylenebis(methy-lene)diphosphonate, tris(β-dimethoxy-phosphoryl)ethylphosphate, nitrogen containing oligomeric phosphonate were synthesized by the Arbuzov rearrangement, epoxides open-loop and one-pot. The effects of the catalysts, the reaction temperature, the reaction time, the reaction molecular ratio and the mass of the catalyst on the reaction yield were investigated by orthogonal experiment and single factor. The optimal reaction conditions of tetramethyl,4-phenylene-bis(methylene)diphosphonate was obtained:trimethylphosphate: dichlorobenzyl mole ratio2.8, at130℃for6h, using3%the mass catalyst of reaction.The optimal reaction conditions of tetrethy1,4-phenylenebis(methylene)diphosphonate was obtained:triethyl phosphate:dichlorobenzymole ratio3.0, at140℃for6h, using1%the mass catalyst of reaction. The optimal reaction conditions of tris (β-dimethoxy-phosphoryl) ethylphosphate was obtained:trimethyl phosphate:tris(P-chloroethyl)phosphate mole ratio3.4, at155℃for6h, using0.8%the mass catalyst of reaction. The optimal reaction conditions of nitrogen containing oligomeric phosphonate was obtained:dimethyl methyl phosphonate:phosphorus pentoxide mole ratio2.0, ethanol:phosphorus pentoxide mass ratio0.4, monoethanolamine:dimethyl methyl phosphonate mole ratio1.25, at80-90℃, for3h. ESI-MS、IR and1HNMR were used to characterize their chemical structures, matching with their target molecules. The thermal degradation behaviors of flame retardants were investigated by TGA. The results showed the four oligomeric phosphonate flame retardants have better thermal stability.The synthetic routes of oligomeric phosphonate flame retardants were environment-friendly, simple process, low energy consumption, and easy to be industrialized.