High-yield hexafluorocyclotriphosphazene synthesis device and method

Abstract

The invention discloses a high-yield hexafluorocyclotriphosphazene synthesis device and a high-yield hexafluorocyclotriphosphazene synthesis method, and relates to the technical field of hexafluorocyclotriphosphazene preparation. A vertical thorn fractionating column is vertically arranged at a gas outlet of the reaction container, a gas outlet of the vertical thorn fractionating column is sequentially connected with an alkali washing device, a pickling device, a water washing device and a condenser, a liquid outlet of the condenser is connected with a storage device, hexachlorocyclotriphosphazene is added into the reaction container, then a reaction solvent is added for dissolution, anhydrous alkali metal fluoride continues to be added, heating reflux stirring reaction is performed, and then the hexachlorocyclotriphosphazene is obtained. Continuously discharging a gas product; a reaction solvent separated after the gas product passes through the vertical thorn fractionating column still enters the reaction container for continuous reaction; the separated gas is sequentially subjected to alkali washing by an alkali washing device, acid washing by an acid washing device and water washing by a water washing device, and then enters a condenser to be condensed and liquefied to obtain the hexafluorocyclotriphosphazene. Compared with a traditional kettle type synthesis reaction method, the method has the advantages of mild reaction conditions, no need of adding a catalyst, good product quality, simple operation, excellent yield and low production cost.

Description

Technical Field

[0001] The present application relates to the technical field of hexafluorocyclotriphosphazene preparation, and in particular to a high-yield hexafluorocyclotriphosphazene synthesis device and method. Background Art

[0002] Hexafluorocyclotriphosphazene, CAS number: 15599-91-4, molecular formula: P3N3F6, relative molecular weight: 248.93, the structural formula is shown in the figure below:

[0003]

[0004] Hexafluorocyclotriphosphazene contains two flame-retardant elements, P and F, which work synergistically, reducing additive dosage and improving flame retardancy. The F element helps form a superior SEI (solid electrolyte interface) membrane at the electrode interface, improving compatibility between the electrolyte and active materials. It also weakens intermolecular viscosity, reducing the migration resistance of molecules and ions, lowering viscosity, and improving electrolyte conductivity. Therefore, hexafluorocyclotriphosphazene has broad potential applications as a flame-retardant additive for lithium batteries.

[0005] "Synthesis of TCPP Catalyzed by Lewis Acid Ionic Liquids" (Hu Yun, Xia Kedan, Zhang Peng, et al.) discloses dissolving HCCP in an organic solvent, adding a fluorinating agent and a catalyst, and undergoing a fluorination reaction followed by distillation to obtain the target product, hexafluorocyclotriphosphazene. The fluorination reaction temperature is 20°C to 50°C, and the reaction time is 2 to 3 hours. The organic solvent is selected from any one or more of acetonitrile, 1,4-dioxane, n-hexane, acetone, cyclohexane, and tetrahydrofuran, and is added at a solids content of 50% or less. The fluorinating agent is selected from potassium fluoride, sodium fluoride, or lithium fluoride, and the molar ratio of HCCP to fluorinating agent is 1:(6.1-6.5). The catalyst is an ionic liquid catalyst selected from any one of [Nbmm]OH, [Mmim]DMP, and [Bmim]OH, and the catalyst dosage is 0.01% to 0.05% by mass of the HCCP. This method produces hexafluorocyclotriphosphazene with a yield of up to 98.1%. However, this method requires the use of an ionic liquid catalyst, which is costly and unsuitable for large-scale industrial preparation of hexafluorocyclotriphosphazene.

[0006] CN201911324114.0 discloses a method for preparing hexafluorocyclotriphosphazene in a nonpolar solvent. The nonpolar solvent is any one or a combination of n-hexane, cyclohexane, toluene, chlorobenzene, and xylene. The catalyst is a combination catalyst of ethylene glycol monomethyl ether and ethylene glycol monobutyl ether, with the mass ratio of ethylene glycol monomethyl ether to ethylene glycol monobutyl ether being 1:0.1-10, and the amount of the combination catalyst being 0.1%-20% of the mass of the HCCP. The fluorinating agent is potassium fluoride or sodium fluoride, with the mass ratio of the fluorinating agent to the HCCP being 1:1-1.2. The maximum molar yield of hexafluorocyclotriphosphazene produced by this method is 93%. This route also requires the use of a catalyst product, which increases production costs and makes large-scale industrial production difficult.

[0007] CN 201510175894.2 uses a non-volatile, pollution-free, and reusable ionic liquid as a solvent. HCCP is dissolved in the ionic liquid, a fluorinating agent is added to carry out a fluorination reaction, and high-purity hexafluorocyclotriphosphazene is produced by distillation. Ionic liquid solvents are relatively expensive and are not suitable for industrial production.

[0008] CN202210690022.X discloses a method for continuously preparing hexafluorocyclotriphosphazene under solvent-free conditions, the main steps of which are as follows: (1) adding HCCP and a catalyst to a reactor and heating the reactor to 120°C to 250°C; wherein the catalyst is selected from fluorides or chlorides of Sb, Cr, Fe, La, Mn, Ru, Rh, Sn, Ti, and Mo, and n(HCCP):n(catalyst)=1:(0.01-0.5). (2) liquid HCCP and AHF are continuously introduced into the reactor to obtain hexafluorocyclotriphosphazene through a liquid-phase fluorine-chlorine exchange reaction; wherein the liquid HCCP is preheated to 120°C to 150°C, and n(HCCP):n(AHF)=1:(3-20). (3) hexafluorocyclotriphosphazene continuously escapes from the reactor, and after passing through a heat exchanger, a crude hexafluorocyclotriphosphazene product is obtained, which is then sequentially washed with alkali, washed with water, dried, and melt crystallized to obtain a hexafluorocyclotriphosphazene product. The hexafluorocyclotriphosphazene product prepared by this method has a high yield (up to 97.3%) and a purity of more than 99.9%. This route has complex operations, high costs and obvious disadvantages.

[0009] Another example is the synthesis method of hexafluorocyclotriphosphazene disclosed in CN202011114599.3, which dissolves hexachlorocyclotriphosphazene in an organic solvent, adds a fluorinating agent and a catalyst, and performs distillation after a fluorination reaction to obtain the target product hexafluorocyclotriphosphazene. The synthesis method of hexafluorocyclotriphosphazene of the present invention has a mild reaction temperature, a simple and easy-to-operate process, a high yield, a short time consumption, a high purity, a green economy, and is convenient for industrial production. However, the document does not disclose the actual purity of the obtained product or the content of hexafluorocyclotriphosphazene in the product, and the mass spectrum provided is Figure 3The molecular weight of the obtained product is not the relative molecular weight of hexafluorocyclotriphosphazene: 248.93, but 246.1, which is an error, indicating that the purity of the obtained product is low. Summary of the Invention

[0010] The object of the present invention is to provide a high-yield hexafluorocyclotriphosphazene synthesis device and method thereof, so as to solve the problems of complex operation and high cost of the existing method.

[0011] To solve the above technical problems, the present invention adopts the following technical solution: a high-yield hexafluorocyclotriphosphazene synthesis device, characterized in that it includes a reaction vessel, a vertically arranged vertical thorn fractionation column at the gas outlet of the reaction vessel, the gas outlet of the vertical thorn fractionation column is connected to an alkali washer, an acid washer, a water washer, and a condenser in sequence, and the liquid outlet of the condenser is connected to a storage.

[0012] A further technical solution is that the reaction container is in the shape of a tank, a stirring paddle is provided in the tank, a feed port is provided on one side of the top of the tank, a vertical thorn distillation column is provided on the other side of the top, and a discharge port is provided at the bottom.

[0013] A further technical solution is that a plurality of downwardly inclined inclined plates are staggered inside the vertical thorn fractionation column tube body, a heat exchange interlayer is provided on the outside of the tube body side wall, and circulating cooling water is passed through the heat exchange interlayer.

[0014] A further technical solution is that the alkali cleaner, the acid cleaner and the water cleaner are all sealed tanks, the air inlet end of the connecting pipe is immersed below the liquid surface, and the air outlet end is located above the liquid surface.

[0015] A further technical solution is that the device synthesizes hexafluorocyclotriphosphazene in the following steps:

[0016] S1. Hexachlorocyclotriphosphazene was added to the reaction vessel, and then the reaction solvent was added to dissolve the mixture. Anhydrous alkali metal fluoride was added and the mixture was stirred under reflux for 3 to 5 hours, and the gaseous product was continuously discharged.

[0017] S2. The reaction solvent separated from the gas product after passing through the vertical thorn distillation column continues to enter the reaction vessel to continue the reaction; the separated gas is washed with alkali in the alkali washer, acid in the acid washer, and water in the water washer, and then enters the condenser for condensation and liquefaction to obtain hexafluorocyclotriphosphazene, which is temporarily stored in a storage vessel.

[0018] A further technical solution is that in step S1, the anhydrous alkali metal fluoride is any one of anhydrous potassium fluoride, anhydrous sodium fluoride, and anhydrous cesium fluoride; the reaction solvent is any one of anhydrous tetrahydrofuran, anhydrous acetonitrile, anhydrous ethyl acetate, n-hexane, toluene, and anhydrous DMF; the molar ratio of hexachlorocyclotriphosphazene to anhydrous alkali metal fluoride is 1:5-9, and the amount of the reaction solvent is 1000-1100 mL / mol hexachlorocyclotriphosphazene.

[0019] A further technical solution is that the reflux reaction temperature in step S1 is 70-80°C.

[0020] A further technical solution is that in step S2, the alkali washer is charged with a sodium hydroxide solution with a concentration of 1 to 10 mol / L; the acid washer is charged with a sulfuric acid solution with a concentration of 1 to 10 mol / L; and the water washer is charged with a deionized pure water solution.

[0021] A further technical solution is that the temperature of the condensation circulating water in the condenser is 15-25°C, and the temperature of the condensation recovery product hexafluorocyclotriphosphazene is 45-55°C.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. A stirred reaction vessel is used for heating and reflux to obtain a mixed gas containing hexafluorocyclotriphosphazene. The reaction solvent is condensed through a vertical distillation column and continues to enter the reaction. The other gases are sequentially washed with alkali in an alkali washer, acid in an acid washer, and water in a water washer before entering a condenser for condensation and liquefaction to obtain hexafluorocyclotriphosphazene. This achieves continuous discharge and continuous treatment of the reaction gas, promotes the forward reaction, and improves the yield of hexafluorocyclotriphosphazene.

[0024] 2. The preparation process uses hexachlorocyclotriphosphazene and anhydrous alkali metal fluoride as raw materials in an organic solvent. This reaction can achieve a high yield of hexafluorocyclotriphosphazene without the use of a catalyst. Low-cost fluoride salts are used as raw materials, and the resulting product is collected, condensed, and separated in real time during the reaction, promoting the forward reaction and effectively increasing the yield and purity of the hexafluorocyclotriphosphazene. Furthermore, the solvent is separated from the product in real time, facilitating subsequent purification steps and improving the purity of the product. The overall synthesis process is environmentally friendly, green, and energy-efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the structure of the synthesis device in the present invention;

[0026] Figure 2 is the phosphorus spectrum of the product prepared in Example 1;

[0027] Figure 3 This is the fluorine spectrum of the product prepared in Example 1;

[0028] Among them, 1-reaction container, 2-vertical thorn fractionation column, 3-alkali washer, 4-acid washer, 5-water washer, 6-condenser, 7-storage container. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the present invention is not limited in any way. Any changes or improvements made based on the teachings of the present invention fall within the scope of protection of the present invention.

[0030] Unless otherwise specified, the materials and instruments used in the following examples were obtained from commercial channels; the detection methods used were all existing methods unless otherwise specified.

[0031] Example 1

[0032] Figure 1 A high-yield hexafluorocyclotriphosphazene synthesis apparatus is shown. The apparatus comprises a tank-shaped reaction vessel 1 equipped with a stirring paddle, a feed inlet on one side of the top, a vertically mounted vertical distillation column 2 on the other side, and a discharge port at the bottom. The vertical distillation column 2 has multiple, staggered, downwardly sloping plates arranged inside the inner tube. A heat exchange interlayer is located on the outer side of the tube, through which circulating cooling water flows. The gas outlet at the top of the vertical distillation column 2 is piped into the lower portion of an alkali scrubber 3. The other end of a connecting pipe extending above the alkali scrubber 3 is piped into the lower portion of an acid scrubber 4. Another connecting pipe extends above the acid scrubber 4 into the lower portion of a water scrubber 5. Alkali-soluble impurities in the gas product are first removed. The gas then enters the acid scrubber 4, where acid-soluble impurities are removed. Finally, a water scrubber is performed to prevent contamination of the product by residual acid or alkali droplets and to remove water-soluble impurities. The water scrubber 5 is connected to the air inlet of the condenser 6 via a pipe above the liquid level. Condensate circulating water at a temperature of 15-25°C flows into the condenser 6, condensing the gas to 45-55°C. The hexafluorocyclotriphosphazene precipitates out of the condenser 6 and is temporarily stored in the reservoir 7 through the bottom drain port. The condensate circulating water in the condenser 6 exchanges heat with the gas and is then used to cool the containers of the alkali scrubber 3, the acid scrubber 4, and the water scrubber 5. To prevent gas escape, the alkali scrubber 3, the acid scrubber 4, and the water scrubber 5 can be manufactured as sealed tanks with an opening at the top for pipe installation and fixation.

[0033] The steps of synthesizing hexafluorocyclotriphosphazene using the above device are as follows:

[0034] S1. Hexachlorocyclotriphosphazene (100.0 g, 287.7 mmol) was weighed into a 500 mL reaction vessel 1. 300 mL of anhydrous tetrahydrofuran was added and stirred to dissolve the raw material. Anhydrous sodium fluoride (72.5 g, 1.73 mol) was then added. The reaction vessel 1 was heated to 75°C and stirred under reflux for 3 hours, after which the gaseous product was discharged.

[0035] S2. The reaction solvent separated from the gas product after passing through the vertical distillation column 2 continues to enter the reaction vessel 1 to continue the reaction; the separated gas is sequentially washed with alkali in the alkali washer 3, acid in the acid washer 4, and water in the water washer 5, and then enters the condenser 6 for condensation and liquefaction to obtain hexafluorocyclotriphosphazene, which is temporarily stored in the storage 7.

[0036] The alkaline washer 3 is filled with a sodium hydroxide solution with a concentration of 5 mol / L; the acid washer 4 is filled with a sulfuric acid solution with a concentration of 6 mol / L; and the water washer 5 is filled with a deionized pure water solution.

[0037] The temperature of the condensation circulating water in the condenser 6 is 15-25° C., and the temperature of the condensed recovered product hexafluorocyclotriphosphazene is 45-55° C. The reaction is stopped until no more liquid is distilled from the condenser 6, and 64.4 g of the product hexafluorocyclotriphosphazene is obtained with a yield of 89.9%.

[0038] The phosphorus spectrum of the obtained substance is as follows Figure 2 The fluorine spectrum of the obtained substance is shown as Figure 3 As shown by Figure 2 、 3 It can be seen that the obtained product has a hexafluorocyclotriphosphazene structure and is hexafluorocyclotriphosphazene.

[0039] Example 2

[0040] The difference from Example 1 is:

[0041] The raw material hexachlorocyclotriphosphazene (200.0 g, 575.3 mmol) was weighed into a 1000 mL reaction vessel 1, and 600 mL of anhydrous tetrahydrofuran was added to dissolve it. Then, anhydrous potassium fluoride (250.3 g, 4.32 mol) was added. After heating to 75°C and stirring at reflux at 75°C for 3 hours, the distillate at a temperature of 45-55°C was collected until no more liquid was distilled to stop the reaction. The product hexafluorocyclotriphosphazene was 131.7 g with a yield of 91.9%.

[0042] Example 3

[0043] The difference from Example 1 is:

[0044] The raw material hexachlorocyclotriphosphazene (200.0 g, 575.3 mmol) was weighed into a 1000 mL reaction vessel 1, and 600 mL of anhydrous acetonitrile was added to dissolve it. Then, anhydrous potassium fluoride (283.6 g, 4.89 mol) was added. After heating to 75°C and stirring under reflux for 4 hours, the distillate at a temperature of 45-55°C was collected until no more liquid was distilled. The reaction was stopped to obtain 128.5 g of the product hexafluorocyclotriphosphazene with a yield of 89.7%.

[0045] Example 4

[0046] The difference from Example 1 is:

[0047] The raw material hexachlorocyclotriphosphazene (500.0 g, 1.44 mol) was weighed into a 2000 mL reaction vessel 1, and 1500 mL of anhydrous tetrahydrofuran was added to dissolve it. Anhydrous cesium fluoride (1420.0 g, 9.35 mol) was then added. The temperature was raised to 75°C and refluxed with stirring for 4 hours. The distillate at a temperature of 45-55°C was collected until no more liquid was distilled. The reaction was stopped to obtain 331.9 g of the product hexafluorocyclotriphosphazene with a yield of 92.7%.

[0048] Example 5

[0049] The difference from Example 1 is:

[0050] The raw material hexachlorocyclotriphosphazene (1000.0 g, 2.88 mol) was weighed into a 5000 mL reaction vessel 1, and 3000 mL of anhydrous ethyl acetate was added to dissolve it. Then, anhydrous potassium fluoride (1418.0 g, 24.5 mol) was added. After heating to 75° C. and stirring under reflux for 3 hours, the distillate at a temperature of 45-55° C. was collected until no more liquid was distilled to stop the reaction. The product hexafluorocyclotriphosphazene was obtained, 658.6 g, with a yield of 92.0%.

[0051] Example 6

[0052] The difference from Example 1 is:

[0053] The raw material hexachlorocyclotriphosphazene (1000.0 g, 2.88 mol) was weighed into a 5000 mL reaction vessel 1, and 3000 mL of n-hexane was added to dissolve it. Then, anhydrous potassium fluoride (1418.0 g, 24.5 mol) was added. After heating to 75° C. and stirring under reflux for 5 hours, the distillate at a temperature of 45-55° C. was collected until no more liquid was distilled. The reaction was stopped to obtain 641.8 g of the product hexafluorocyclotriphosphazene with a yield of 89.6%.

[0054] Example 7

[0055] The difference from Example 1 is:

[0056] Hexachlorocyclotriphosphazene (1000.0 g, 2.88 mol) was weighed into a 5000 mL reaction vessel (1). 3000 mL of toluene was added to dissolve the product. Anhydrous potassium fluoride (1418.0 g, 24.5 mol) was then added. The mixture was heated to 75°C and stirred under reflux for 5 hours. The distillate was collected at 45-55°C until no more liquid distilled out. The reaction was terminated, yielding 611.7 g of the product, hexafluorocyclotriphosphazene. The yield was 85.4%.

[0057] Example 8

[0058] The difference from Example 1 is:

[0059] The raw material hexachlorocyclotriphosphazene (1000.0 g, 2.88 mol) was weighed into a 5000 mL reaction vessel 1, and 3000 mL of anhydrous DMF was added to dissolve it. Then, anhydrous potassium fluoride (1418.0 g, 24.5 mol) was added. After heating to 75° C. and stirring under reflux for 5 hours, the distillate at a temperature of 45-55° C. was collected until no more liquid distilled out. The reaction was stopped to obtain 674.5 g of the product hexafluorocyclotriphosphazene with a yield of 94.2%.

[0060] Example 9

[0061] The difference from Example 1 is that: the reaction vessel 1 is heated to 80° C. and refluxed with stirring for 3 hours;

[0062] The alkali washer 3 is filled with a sodium hydroxide solution having a concentration of 1 mol / L;

[0063] The pickling vessel 4 is filled with a sulfuric acid solution having a concentration of 1 mol / L.

[0064] Example 10

[0065] The difference from Example 1 is that: the reaction vessel 1 is heated to 70° C. and refluxed with stirring for 3 hours;

[0066] The alkali washer 3 is filled with a sodium hydroxide solution having a concentration of 10 mol / L;

[0067] The pickling vessel 4 is filled with a sulfuric acid solution having a concentration of 10 mol / L.

[0068] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-yield hexafluorocyclotriphosphazene synthesis device, characterized by: The invention comprises a reaction container (1), wherein a vertical thorn fractionation column (2) is vertically arranged at the gas outlet of the reaction container (1), the gas outlet of the vertical thorn fractionation column (2) is connected to an alkali washer (3), an acid washer (4), a water washer (5), and a condenser (6) in sequence, and the liquid outlet of the condenser (6) is connected to a storage container (7).

2. A high-yield hexafluorocyclotriphosphazene synthesis device according to claim 1, characterized in that: The reaction container (1) is in the shape of a tank, a stirring paddle is provided in the tank, a feed port is provided on one side of the top of the tank, a vertical thorn fractionation column (2) is provided on the other side of the top, and a discharge port is provided at the bottom.

3. A high-yield hexafluorocyclotriphosphazene synthesis device according to claim 1, characterized in that: The vertical thorn fractionation column (2) has a plurality of inclined plates arranged in a staggered manner and tilted downwards on the inner side of the tube body, and a heat exchange interlayer is arranged on the outer side of the tube body side wall, and circulating cooling water is passed through the heat exchange interlayer.

4. A high-yield hexafluorocyclotriphosphazene synthesis device according to claim 1, characterized in that: The alkali washer (3), the acid washer (4) and the water washer (5) are all sealed tanks, the air inlet ends of the connecting pipes thereof are immersed below the liquid surface, and the air outlet ends thereof are located above the liquid surface.

5. A high-yield hexafluorocyclotriphosphazene synthesis device according to any one of claims 1 to 4, characterized in that: The steps of synthesizing hexafluorocyclotriphosphazene by the device are as follows: S1. Hexachlorocyclotriphosphazene was added to the reaction vessel (1), and then the reaction solvent was added to dissolve the mixture. Anhydrous alkali metal fluoride was added and the mixture was stirred under reflux for 3 to 5 hours, and the gaseous product was continuously discharged. S2. The reaction solvent separated from the gas product by the vertical thorn fractionation column (2) is still fed into the reaction vessel (1) to continue the reaction; the separated gas is sequentially washed with alkali by the alkali washer (3), washed with acid by the acid washer (4), and washed with water by the water washer (5), and then fed into the condenser (6) for condensation and liquefaction to obtain hexafluorocyclotriphosphazene, which is temporarily stored in the storage vessel (7).

6. A high-yield hexafluorocyclotriphosphazene synthesis device according to claim 1, characterized in that: In step S1, the anhydrous alkali metal fluoride is any one of anhydrous potassium fluoride, anhydrous sodium fluoride, and anhydrous cesium fluoride; the reaction solvent is any one of anhydrous tetrahydrofuran, anhydrous acetonitrile, anhydrous ethyl acetate, n-hexane, toluene, and anhydrous DMF; the molar ratio of hexachlorocyclotriphosphazene to anhydrous alkali metal fluoride is 1:5-9, and the amount of the reaction solvent used is 1000-1100 mL / mol hexachlorocyclotriphosphazene.

7. A high-yield hexafluorocyclotriphosphazene synthesis device according to claim 1, characterized in that: The reflux reaction temperature in step S1 is 70-80°C.

8. The high-yield hexafluorocyclotriphosphazene synthesis device according to claim 1, characterized in that: In step S2, the alkaline cleaning device (3) is charged with a sodium hydroxide solution having a concentration of 1 to 10 mol / L; the acid cleaning device (4) is charged with a sulfuric acid solution having a concentration of 1 to 10 mol / L; and the water cleaning device (5) is charged with a deionized pure water solution.

9. A high-yield hexafluorocyclotriphosphazene synthesis device according to claim 1, characterized in that: The temperature of the condensation circulating water in the condenser (6) is 15-25°C, and the temperature of the condensation recovery product hexafluorocyclotriphosphazene is 45-55°C.

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