The novel flame retardant 1,2,3-tris(5,5-dimethyl-1,3-dioxaphosphorinanyl-2-oxy)benzene was synthesized via neopentyl alcohol, phosphous oxychloride, 1,2,3-trihydroxybenzene by a two step reaction, and its structure identified and studied by elemental analysis, IR, 1H NMR, MS techniques and X-ray diffraction analysis. The crystal belongs to triclinic, space group P-1 with unit cell dimensions a＝0.70450(14) nm, b＝1.2850(3) nm, c＝1.5609(3) nm, α＝69.19(3)°, β＝86.29(3)°, γ＝86.60(3)°, V＝1.3171(5) nm3, Dc＝1.438 g/cm3, μ＝0.286 mm－1, F(000)＝600 and Z＝2. The final R＝0.0574 and Rw＝0.1061 for 4635 unique reflections [I＞2σ(I)]. The result of thermal analysis shows that the novel flame retardant has a high thermal stability and excellent char forming ability. The results demonstrate that the title compound is effective on the flame retardancy of epoxy resin, and the optimum addition content is 20%.

Key words: intumescent flame retardant, crystal structure, thermogravimetric analysis