Hexabromocyclotriphosphazene and a method for its preparation
By reacting N-bromocyanurate monosodium salt with hexachlorocyclotriphosphazene under alkaline conditions, the problem of using liquid bromine in the existing synthesis of hexabromocyclotriphosphazene has been solved, realizing a high-yield and environmentally friendly synthetic route suitable for industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HENAN FLUORINE BASED NEW MATERIAL TECH CO LTD
- Filing Date
- 2026-04-01
- Publication Date
- 2026-06-23
AI Technical Summary
Existing methods for synthesizing hexabromocyclotriphosphazene use volatile and toxic liquid bromine, and involve high reaction temperatures and long reaction times, resulting in low yields and the generation of large amounts of waste, making them unsuitable for industrial application.
Sodium N-bromocyanurate (SMBI) was used as the brominating agent to react with hexachlorocyclotriphosphazene under alkaline conditions. Pyridine or triethylamine was used as the base, and zinc fluoride or magnesium fluoride was used as the catalyst. The reaction was carried out at 80-140℃ for 10 hours to avoid the use of liquid bromine and simplify the synthetic route.
A high-yield synthesis of hexabromocyclotriphosphazene was achieved. The operation is simple, reduces the use of toxic substances and the generation of waste, and has good potential for industrial production.
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Figure CN122255184A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of inorganic polymer materials technology, and particularly relates to a hexabromocyclotriphosphazene and its preparation method. Background Technology
[0002] Polyphosphazenes are a unique class of compounds whose main chain is composed of alternating single and double bonds of nitrogen and phosphorus. The phosphorus atom is attached to two identical or different substituents, thus these polymers exhibit a wide range of similar and different physical and chemical properties. As a high-tech material, polyphosphazenes have important applications in aerospace, military industry, petrochemicals, functional materials, and biomedicine. Currently, with societal development, research on polyphosphazenes is increasing, with a focus on hexachlorocyclotriphosphazenes (HCTs). Hexafluorocyclotriphosphazenes play a crucial role as additives in preventing combustion and explosion in lithium batteries. In contrast, hexabromocyclotriphosphazenes have been studied less due to their demanding synthesis process. However, hexabromocyclotriphosphazenes are also an important phosphazene intermediate with broad application prospects in fine chemicals and biopharmaceuticals.
[0003] The reported synthesis methods mainly include: 1. PBr5 is prepared by reacting PBr3 with liquid Br2, and then reacted with ammonium bromide in tetrabromoethane to produce hexabromocyclotriphosphazene. This method has a long reaction time, the solvent is highly toxic, and the liquid bromine is toxic and volatile.
[0004] 2. Using red phosphorus and liquid Br2 to replace PBr3 to prepare PBr5 results in the simultaneous formation of phosphazene bromide during the preparation of phosphorus pentabromide, leading to a low yield.
[0005] 3. PBr5 and ammonium bromide were reacted directly in a tetrabromoethane solution. However, due to the excessive thermal decomposition and the loss of raw materials during the reaction, the yield of the final product, hexabromocyclotriphosphazene, was extremely low. Summary of the Invention
[0006] In view of the shortcomings of existing technologies for the synthesis of hexabromocyclotriphosphazene, such as the use of volatile and toxic liquid bromine, high reaction temperature, long reaction time, low yield, and large amount of waste, the present invention aims to provide a method for synthesizing the polyphosphazene compound hexabromocyclotriphosphazene. This method uses inexpensive and readily available raw materials, is simple to operate, has a very short route, does not produce toxic compounds, and generates less waste, thus having great industrial production value.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A hexabromocyclotriphosphazene, the structure of which is shown in Formula I: .
[0008] Another object of the present invention is to provide a method for preparing hexabromocyclotriphosphazene, the synthetic route of which is shown below: .
[0009] The specific synthesis method includes the following steps: The brominating agent used in this reaction is SMBI (monosodium N-bromocyanurate), wherein the amount of SMBI is in excess, and the molar ratio of SMBI to hexachlorocyclotriphosphazene is 6~7:1, preferably 6.5:1. The solvent used in this step is either EMC or dioxane, preferably EMC. The reaction is carried out under alkaline conditions, and the base used is either pyridine or triethylamine, preferably pyridine. The catalyst used is either zinc fluoride or magnesium fluoride, preferably zinc fluoride. The reaction temperature is 80~140℃, preferably 100℃, and the reaction time is 10h.
[0010] Mechanism: The reaction system activates the monosodium N-bromocyanurate under alkaline conditions, promoting the formation of Br ions, which in turn promotes the formation of P-Br bonds, breaks the P-Cl bonds, and allows Br in the monosodium N-bromocyanurate to undergo nucleophilic substitution.
[0011] The advantages of this invention are: 1. This invention provides a novel method for synthesizing hexabromocyclotriphosphazene, which is simple in synthesis, has a very short route, and is easy to operate experimentally; 2. This invention uses a direct reaction between hexachlorocyclotriphosphazene and SMBI (sodium N-bromocyanurate), avoiding the significant safety hazards to the environment and workers caused by the use of volatile liquid bromine. Attached Figure Description
[0012] Figure 1 This is the NMR spectrum of the white solid hexabromocyclotriphosphazene prepared in Example 1 of this invention. Detailed Implementation
[0013] This invention provides a method for synthesizing a polyphosphazene compound, hexabromocyclotriphosphazene, having the structure shown in Formula I; Formula I: .
[0014] This invention also provides a method for preparing the polyphosphazene compound hexabromocyclotriphosphazene described above, as follows: Example 1 Under nitrogen protection, 300 ml of EMC, 17.35 g (0.05 mol) of hexachlorocyclotriphosphazene, 23.7 g (0.3 mol) of pyridine, 1.03 g (0.01 mol) of ZnF2, and 64.8 g (0.3 mol) of N-bromocyanuric acid monosodium salt were added to a 500 mL three-necked flask. After reacting at 100 °C for 10 h, the reaction solution was directly filtered and then cooled at 0 °C to crystallize, yielding 28.7 g (0.047 mol) of white solid hexabromocyclotriphosphazene with a purity of 98% and a yield of 93.9%.
[0015] Example 2 Under nitrogen protection, 300 ml of EMC, 17.35 g (0.05 mol) of hexachlorocyclotriphosphazene, 30.3 g (0.3 mol) of triethylamine, 1.03 g (0.01 mol) of ZnF2, and 64.8 g (0.3 mol) of N-bromocyanuric acid monosodium salt were added to a 500 mL three-necked flask. After reacting at 100 °C for 10 h, the reaction solution was directly filtered and then cooled at 0 °C to crystallize, yielding 26.7 g (0.044 mol) of white solid hexabromocyclotriphosphazene with a purity of 98.2% and a yield of 87.3%.
[0016] Example 3 Under nitrogen protection, 300 ml of EMC, 17.35 g (0.05 mol) of hexachlorocyclotriphosphazene, 23.7 g (0.3 mol) of pyridine, 0.62 g (0.01 mol) of MgF2, and 64.8 g (0.3 mol) of N-bromocyanuric acid monosodium salt were added to a 500 mL three-necked flask. After reacting at 100 °C for 10 h, the reaction solution was directly filtered and then cooled at 0 °C to crystallize, yielding 26.8 g (0.044 mol) of white solid hexabromocyclotriphosphazene with a purity of 96.6% and a yield of 87.5%.
[0017] Example 4 Under nitrogen protection, 300 ml of dioxane, 17.35 g (0.05 mol) of hexachlorocyclotriphosphazene, 23.7 g (0.3 mol) of pyridine, 1.03 g (0.01 mol) of ZnF2, and 64.8 g (0.3 mol) of N-bromocyanuric acid monosodium salt were added to a 500 mL three-necked flask. After reacting at 100 °C for 10 h, the reaction solution was directly filtered and then cooled at 0 °C to crystallize, yielding 27.4 g (0.047 mol) of white solid hexabromocyclotriphosphazene with a purity of 97.5% and a yield of 89.6%.
Claims
1. A hexabromocyclotriphosphazene, characterized in that, Its structure is shown in Equation I: .
2. The method for preparing hexabromocyclotriphosphazene according to claim 1, characterized in that, The process includes the following steps: dissolving the brominating agent and hexachlorocyclotriphosphazene in a solvent and reacting them under alkaline conditions to obtain the product.
3. The method for preparing hexabromocyclotriphosphazene as described in claim 2, characterized in that: The brominating agent is sodium N-bromocyanurate.
4. The method for preparing hexabromocyclotriphosphazene according to claim 2, characterized in that: The molar ratio of the brominating agent to hexachlorocyclotriphosphazene is 6~7:
1.
5. The method for preparing hexabromocyclotriphosphazene according to claim 2, characterized in that: The solvent is one of EMC and dioxane.
6. The method for preparing hexabromocyclotriphosphazene according to claim 2, characterized in that: The base is one of pyridine and triethylamine.
7. The method for preparing hexabromocyclotriphosphazene according to claim 2, characterized in that: The catalyst is one of zinc fluoride and magnesium fluoride.
8. The method for preparing hexabromocyclotriphosphazene according to claim 2, characterized in that: The reaction temperature is 80~140℃.