Synthesis and characterization of a flame retardant:pentaerythritol biphosphorate melamine salt

Flame-retardant of pentaerythritol biphosphorate melamine salt was synthesized using pentaerythritol,phosphorous oxychloride,and melamine as raw materials by two steps.The results showed that the optimum synthetic process was:in the first step,n[C(CH2OH)4] ∶n(POCl3)=1 ∶2.2,reaction time 7 h,reaction temperature 80 ℃,the yield 88%;in the second step,n(intermediate) ∶n(C3N6H6)=1 ∶2,reaction time 0.5 h,reaction temperature 80 ℃,the yield 98%.Chemical structure of the product was confirmed by IR and elemental analysis.