Synthesis Of Phosphazene Compounds In Ionic Liquids

Hexachlorocyclotriphosphazene, with a backbone of alternating phosphorus and nitrogenatoms, is an important feedstock to prepare phosphazene compounds, Because the chlorideatoms on hexachlorocyclotriphosphazene show high reacticity, it can be substituted bymany useful groups which can be used in many fileds, such as membrane technology, fireretardancy, special rubber, elastomers, optical and biomedical materials etc. There isrealistic value for us to study the phosphazene compounds because phosphorus resources isrich in China. Which is considered a environmentally friendly solvents, Ionic liquids isdiffer from molecular solvents by their unique ionic character and their “structure andorganization” which can lead to specific effects. On this basis,hexachlorocyclotriphosphazene and polyphosphazene were prepared by reaction in ionicliquids.Hexachlorocyclotriphosphazene was prepared by the reaction of ammonium chloridewith phosphorus pentachloride in the ionic liquids with chlorine anion. First, The reactioneffects of hexachlorocyclotriphosphazene in1-butyl-3-methylimidazolium chloride/znicchloride ionic liquids was compared with each other. The effect of1-butyl-3-methylimidazolium chloride/znic chloride ratio, reaction temperature, theamount of the ionic liquids used in this reaction were investigated. The experimental resultsshowed that the highest yield was achieved in71.9%at the temperature of130℃after5husing1-butyl-3-methylimidazolium chloride and ZnCl₂（mole ration is6:1） as thepromoting media, and this catalyst could be used7times almost without losing its catalyticactivity. Compared with conventional synthetic methods, that the ionic liquids were used asan alternative for the traditional organic solvent, the after-treatment is very simple, the ionicliquid can be recycled, and greatly reducing the use of organic solvents.Second, the reaction effects of hexachlorocyclotriphosphazene in different ionic liquidswas compared with each other, changing the cation structure, We found that theimidazolium ionic liquids is superior to the quaternary ammonium ionic liquids andimidazolium salts of different alkyl groups has little effect on the yield. Different metallicsalts （ZnCl₂, FeCl₃, CuCl₂, NiCl₂, CrCl₃, AlCl₃, CuCl, MgCl₂） with 1-butyl-3-methylimidazolium chloride were tested for this reaction and found that thereaction effect in this1-butyl-3-methylimidazolium chloride/znic chloride ionic liquid isexcellent.At last, hexachlorocyclotriphosphazene was also synthesized in ionic liquid ammoniumcarbamate or ammonium acetate as the nitrogen source, but the effect of that reaction is notideal. The ploymerization of hexachlorocyclotriphosphazene was also experimented inthese ionic liquids.