Method for synthesizing flame retardant hexaphenoxy cyclotriphosphazene

Abstract

The invention discloses a method for synthesizing a flame retardant hexaphenoxy cyclotriphosphazene. The method is characterized by comprising the following steps of: performing a one-pot reaction on hexachlorocyclotriphosphazene, phenol, alkali metal hydroxides and other raw materials in a solvent system consisting of aromatic hydrocarbon or aryl halide and water by adopting noncyclic polyether as a catalyst at the temperature of between 20 and 30 DEG C for 3 to 5 hours; heating to the temperature of between 80 and 100 DEG C, reacting for 3 to 5 hours; reclaiming hydrated aromatic hydrocarbon or aryl halide through cooling, separation, washing and depressed pressure distillation after the reaction is completed; and cooling and coagulating the residues to obtain a white crystal solid powder product, wherein the yield is over 95 percent. The method has the characteristics of short reaction time, low cost, good quality and the like, is simple and safe in operation, and is environmentally-friendly and suitable for industrial production and application.

Description

technical field [0001] The invention belongs to a preparation method of a compound having three phosphorus atoms as ring heteroatoms, and relates to a synthesis method of a flame retardant hexaphenoxycyclotriphosphazene. Background technique [0002] As a typical representative of cyclic phosphazene compounds, hexaphenoxycyclotriphosphazene has outstanding characteristics such as high heat resistance, excellent hydrolysis resistance, good compatibility with polymer materials, and remarkable flame retardant efficiency. One of the hotspots of combustion research. [0003] There are many research reports on the synthesis method of hexaphenoxycyclotriphosphazene at home and abroad, which can be roughly divided into three types. The first method is catalyzed by an inorganic salt acid-binding agent, reacted in a hydrophilic organic solvent, and the post-treatment needs to be refined with a hydrophobic solvent to obtain the product. For example, Chinese patent application 0012236...

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Problems solved by technology

This phase-transfer catalytic method has slow reaction speed, long reaction time, poor product quality, high content of low-substitute impurities, and a yield of only 70% to 80%, and the amount of quaternary ammonium salt or quaternary phosphonium salt catalyst is large, expensive, and difficult to obtain. Recycling leads to rising costs, which is not conducive to industrial transformation

[0005] The third method does not need a catalyzer, but the reaction is carried out step by step, first prepares the phenoxide, and then reacts with hexachlorocyclotriphosphazene, and after the reaction is completed, the product is obtained through appropriate post-treatment purification, such as U.S. Patent No. 6,518,836 and U.S. Pat. No. 6,627,122 The sodium phenate solution is prepared by reacting sodium metal and phenol in tetrahydrofuran for 6 hours, and then the sodium phenate solution is added dropwise to the chlorobenzene solution containing hexachlorocyclotriphosphazene, and after reacting for 15 hours, the organic phase is concentrated, and the sodium phenate solution is added again with chlorine Benzene is dissolved, followed by repeated alkali washing, pickling, and water washing to remove the solvent, and the yield reaches 98.5%. Although this method has a high yield, the use of metallic sodium and sodium hydride will cause the reaction to be difficult to control, increasing The risk is increased, the reaction time is long, the operation process is more complicated, and the post-treatment is quite troublesome, and the three wastes are more, which is not conducive to environmental protection; in order to reduce the operational risk caused by using metal sodium, another study uses potassium hydroxide (or Sodium hydroxide) replaces metal sodium (or sodium hydride) and reacts with phenol, as reported by Kong Xiangjian et al. Sodium phenate, drop the tetrahydrofuran solution of hexachlorocyclotriphosphazene, after reacting for 48 hours, distill off the solvent, wash with water several times, and obtain the product after recrystallization, the yield is 95%. Although the product yield is higher in this method, the solvent Tetrahydrofuran is expensive, and is easy to oxidize to generate explosive peroxides. The safety problem is more prominent, and the recovery and purification of water-containing tetrahydrofuran formed after use is not easy; while Yang Mingshan et al. ) reported that phenol and potassium hydroxide were added to toluene and reacted at 110°C for 2h to generate potassium phenate, then the toluene solution of hexachlorocyclotriphosphazene was added dropwise and reacted at 110°C for another 10h, and then the waste residue was removed by suction filtration, and the filtrate was used with different concentrations The potassium hydroxide solution is extracted and washed several times, and finally the solvent is removed by distillation under reduced pressure to obtain the product

Although this method greatly reduces the risk and the reaction time is shorter, the amount of waste liquid is large, the pressure on environmental protection is high, and the product quality is poor (only yellow viscous oily product can be obtained, and the product with better quality should be white crystalline solid). And did not mention the product yield

[0006] In summary, the existing synthetic methods of hexaphenoxycyclotriphosphazene have their own characteristics, but there are more or less long reaction times, complex operations, troublesome separation and purification, low product yield and quality, and high energy consumption. , high cost and high pollution, it is difficult for industrial production to accept

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