Method for purifying ethoxypentafluorocyclotriphosphazene

Abstract

The invention relates to a purification method of ethyoxyl pentafluorocyclotriphosphazene. The purification method comprises the following specific steps: S1, preparing an organic solvent and ethyoxyl pentafluorocyclotriphosphazene into an ethyoxyl solution; s2, the prepared ethyoxyl solution is put into an ultralow-temperature refrigerator at the temperature ranging from-80 DEG C to 0 DEG C for freezing crystallization, and the freezing time ranges from 1 h to 8 h; s3, the frozen ethyoxyl solution is subjected to solid-liquid separation, and solid-state ethyoxyl pentafluorocyclotriphosphazene is obtained; s4, the separated solid ethoxypentafluorocyclotriphosphazene is melted at the room temperature, the melted ethoxypentafluorocyclotriphosphazene is subjected to the sweating process by repeating the steps S1 to S3, and the purity of the ethoxypentafluorocyclotriphosphazene reaches 98% or above. The method can effectively remove impurities in the ethoxypentafluorocyclotriphosphazene, improves the purity of the ethoxypentafluorocyclotriphosphazene, and is simple to operate, efficient, low in energy consumption, economical and environment-friendly.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of ethoxy pentafluorocyclotriphosphazene, in particular to a method for purifying ethoxy pentafluorocyclotriphosphazene. Background Art

[0002] With the development of science and technology and the enhancement of human awareness of environmental protection, new energy vehicles are also ushering in a climax of development. Along with huge economic benefits, new energy vehicles also expose huge safety hazards in actual applications. For example, the mileage is reduced due to battery aging or damage, the charging speed is slowed down due to the decline in battery charging performance, the high and low temperature life of batteries in extreme environments is short, and battery failure causes short circuit or overheating. These problems have become bottlenecks that restrict the further development of new energy vehicles. The key to improving new energy vehicle batteries lies in the preparation of electrolytes. Through a lot of research and development, scientists have concluded that the charging and discharging performance of batteries in extreme environments can be further improved by adding additives. Among them, ethoxypentafluorocyclotriphosphazene is widely used as an additive for electrolytes because of its ultra-high flame retardant properties.

[0003] At present, most of the purification of ethoxy pentafluorocyclotriphosphazene at home and abroad adopts the traditional distillation or vacuum distillation method. This method not only consumes a lot of energy resources in the early stage of solvent separation, but also causes waste of human resources and the long separation time easily increases production costs. In addition, the separation of solvents at high temperatures is prone to catalyze unknown reactions, reduce product yields, and high temperatures themselves have unstable factors, which are prone to cause safety accidents.

[0004] Therefore, the research purpose of the present invention is to design a purification method for ethoxypentafluorocyclotriphosphazene that can effectively remove impurities in ethoxypentafluorocyclotriphosphazene, improve the purity of ethoxypentafluorocyclotriphosphazene, and is simple to operate, efficient, low in energy consumption, economical and environmentally friendly. Summary of the invention

[0005] In view of the technical problems existing in the above-mentioned prior art, the present invention provides a method for purifying ethoxypentafluorocyclotriphosphazene, which can effectively solve the technical problems existing in the above-mentioned prior art.

[0006] The technical solution of the present invention is:

[0007] A method for purifying ethoxy pentafluorocyclotriphosphazene comprises the following specific steps:

[0008] S1, preparing an ethoxy solution by mixing an organic solvent with ethoxy pentafluorocyclotriphosphazene;

[0009] S2, placing the prepared ethoxylated solution into an ultra-low temperature refrigerator at -80°C to 0°C for freezing and crystallization, with a freezing time of 1 to 8 hours;

[0010] S3, performing solid-liquid separation on the frozen ethoxylated solution to obtain solid ethoxylated pentafluorocyclotriphosphazene;

[0011] S4, melting the separated solid ethoxypentafluorocyclotriphosphazene at room temperature, repeating steps S1 to S3 for the melted ethoxypentafluorocyclotriphosphazene to perform a sweating process, so that the purity of the ethoxypentafluorocyclotriphosphazene reaches more than 98%.

[0012] The organic solvent in step S1 is one or more of acetonitrile, n-hexane, ethanol, and cyclohexane.

[0013] The molar ratio of ethoxypentafluorocyclotriphosphazene to the organic solvent in step S1 is 1:1 to 1:20.

[0014] In the step S3, the frozen ethoxylated solution is separated into solid and liquid by pouring or filtering, and the separated solvent is recovered.

[0015] The freezing crystallization of step S2 and the solid-liquid separation of step S3 of the method are achieved by solid ethoxy pentafluorocyclotriphosphazene processing equipment, and the solid ethoxy pentafluorocyclotriphosphazene processing equipment comprises:

[0016] An ultra-low temperature refrigerator, wherein a receiving cavity for placing a container is provided in the middle of the ultra-low temperature refrigerator, and a feed port and a discharge port communicating with the receiving cavity are provided on the left and right sides thereof, and corresponding feed channels and discharge channels are fixedly connected to the ultra-low temperature refrigerator at the feed port and the discharge port respectively;

[0017] The conveying mechanism comprises a conveyor belt penetrating through the accommodating cavity connected to the ultra-low temperature refrigerator, and the belt surface of the conveyor belt is fixed with partitions whose transverse and longitudinal cross-sections are adapted to the feed channel and the discharge channel at intervals, and the distance between two adjacent partitions is less than the length of the feed channel and the discharge channel;

[0018] A containing container is placed on the conveyor belt between two adjacent partitions, wherein a corresponding filter plate is fixedly connected in the containing container, and a plurality of liquid guide holes with a trapezoidal longitudinal section are distributed on the filter plate, and a movable plate is movably installed below the filter plate through a corresponding elastic member, and a protrusion for sealing the liquid guide holes of the filter plate is arranged on the top of the movable plate;

[0019] The electromagnet is installed below the feed channel and is used to adsorb the movable plate to move downward to open the liquid guide hole of the filter plate and form a negative pressure between the movable plate and the filter plate when energized; after the movable plate moves down to its proper position, a normal pressure is formed between the movable plate and the filter plate and the containing container is connected up and down.

[0020] A corresponding filter cloth is detachably fixedly mounted above the filter plate, and the pore size of the filter cloth is smaller than the pore size of the liquid guide hole and smaller than the particle size of the solid ethoxy pentafluorocyclotriphosphazene after freezing.

[0021] The movable plate is composed of an iron main body plate and rubber strips fixedly connected to the edges of the main body plate. The bottom of the containing container forms a liquid collection area with a width that gradually increases from top to bottom. After the movable plate moves down to its position, a distance is set between the edge of the movable plate and the inner side wall of the containing container located in the liquid collection area.

[0022] The inner and outer ends of the discharge channel are respectively set as a closed area and a buffer zone, and the width of the buffer zone of the discharge channel gradually increases from the inside to the outside and is greater than the width of the partition plate; when the holding container moves into the discharge channel, the partition plates on both sides of the holding container are respectively placed in the closed area and the buffer zone.

[0023] The sweating process in step S4 can be carried out by a distillation method, wherein the distillation process needs to be carried out under the protection of a corresponding inert gas.

[0024] The inert gas is one of nitrogen, helium or argon.

[0025] Advantages of the present invention:

[0026] 1) The melt crystallization method of the present invention can be used to purify ethoxy pentafluorocyclotriphosphazene. Not only can the melt crystallization effect be optimized by controlling the melt crystallization conditions, selecting the reaction solvent and the number of sweating times, but also the purification efficiency and product quality can be further improved by combining the vacuum distillation under inert gas protection. The advantages of the melt crystallization method over the traditional rotary evaporation and distillation are: in the early solvent separation stage, it can effectively avoid consuming a large amount of energy and time to evaporate the solvent, and the melt crystallization can avoid the production of a large amount of toxic and harmful tail gas and reduce the consumption of condensation circulating water, which further reduces the production cost and is more conducive to environmental protection and industrial production. The present invention can not only effectively remove impurities in ethoxy pentafluorocyclotriphosphazene, improve the purity of ethoxy pentafluorocyclotriphosphazene, and obtain high-quality ethoxy pentafluorocyclotriphosphazene products, but also the method is simple to operate, has good economic benefits, is easy to realize large-scale production, and also improves production efficiency and reduces costs, and has broad market application prospects.

[0027] 2) The freezing crystallization and solid-liquid separation of the present invention are achieved by a newly designed solid ethoxy pentafluorocyclotriphosphazene treatment device. The solid ethoxy pentafluorocyclotriphosphazene treatment device is used to directly cool and crystallize the ethoxy solution, and the solid-liquid separation is performed by vacuum filtration separation. Compared with the traditional pouring or filtering separation, the solvent attached to the solid surface can be extracted more cleanly and more comprehensively, and the filtering separation effect is better. The movable plate installed by the corresponding elastic member is abutted against the filter plate, so that its protrusion is inserted into the liquid guide hole of the filter plate to form a closure, so that a corresponding receiving area is formed in the upper part of the receiving container for holding the ethoxy solution, and is automatically transported to the ultra-low temperature refrigerator by a conveyor belt for time-limited freezing crystallization. After the crystallization is completed, it continues to be transmitted outward to the discharge channel, and the electromagnet is energized to attract the iron movable plate to move downward. The movable plate is installed with interference fit by fixing corresponding rubber strips around the movable plate, so that when the movable plate is pulled downward, a negative pressure similar to that of a syringe is formed between the movable plate and the filter plate, so that the solvent attached to the solid surface is extracted and filtered through the filter cloth. Compared with the simple filtering and pouring method, the solid-liquid separation effect is more thorough; when the movable plate continues to move downward to the liquid collecting area of ​​the holding container, the distance between the movable plate and the inner wall of the holding container is set, thereby achieving a pressure relief state so that the separated solvent is diverted to the liquid collecting area for collection and discharged through the drain pipe.

[0028] The cooling crystallization and solid-liquid separation processes can be completed by a set of equipment, which not only improves the automation degree of the process, but also effectively ensures the controllability of the operation process, thereby improving the effect of preparing solid ethoxypentafluorocyclotriphosphazene.

[0029] 3) The present invention arranges corresponding partitions on the conveyor belt at intervals, the transverse and longitudinal sections of the partitions are adapted to the feed channel and the discharge channel, and the spacing between two adjacent partitions is smaller than the width of the feed channel and the discharge channel. The partitions are arranged to separate and limit the placement of the containers. More importantly, by setting the cross-section and the distance, no matter how the conveyor belt runs, it can be ensured that at least one partition is arranged at the feed channel, and one partition is arranged at the discharge channel to close the feed port and the discharge port, so as to effectively close the ultra-low temperature refrigerator, ensure the use of the ultra-low temperature refrigerator, and improve the use effect. In addition, a circle of rubber can be fixed to the edge of the partition and installed by interference fit, so as to further improve the sealing degree of the partition to the ultra-low temperature refrigerator on the basis of ensuring the transmission of the conveyor belt, so as to further improve the practical effect of the present invention.

[0030] 4) The discharge channel of the present invention is configured as a closed area and a buffer area, and the width of the buffer area of ​​the discharge channel gradually increases from the inside to the outside and is greater than the width of the partition; when the holding container moves into the discharge channel, the partitions on both sides of the holding container are respectively placed in the closed area and the buffer area, and the partitions placed in the closed area can ensure the sealing of the ultra-low temperature refrigerator, and effectively prevent the cold air of the ultra-low temperature refrigerator from being drawn out when the holding container is pumped out for negative pressure filtration, while the partitions placed in the buffer area form a gap with the discharge channel, thereby effectively ensuring the negative pressure filtration action of the holding container, and further improving the practical effect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic structural diagram of the solid ethoxypentafluorocyclotriphosphazene processing equipment of the present invention.

[0032] Figure 2 It is a cross-sectional view of the solid ethoxypentafluorocyclotriphosphazene processing equipment of the present invention.

[0033] Figure 3 It is a schematic cross-sectional view of the containing container in the present invention.

[0034] Figure 4 It is a schematic diagram of the use status of the containing container in the present invention.

[0035] Figure 5 for Figure 4 Schematic diagram of the usage status when the middle movable plate is moved into place.

[0036] Figure 6 It is a process flow chart of the purification process of the present invention. DETAILED DESCRIPTION

[0037] In order to facilitate understanding by those skilled in the art, the structure of the present invention is further described in detail with reference to the embodiments in conjunction with the accompanying drawings:

[0038] The ethoxypentafluorocyclotriphosphazene used in the following Examples 2 to 6 is commercially available.

[0039] Example 1

[0040] refer to Figure 1-5 , a solid ethoxy pentafluorocyclotriphosphazene treatment device, comprising:

[0041] An ultra-low temperature refrigerator 1, wherein a receiving cavity for placing a container 2 is provided in the middle of the ultra-low temperature refrigerator 1, and a feed port and a discharge port communicating with the receiving cavity are provided on the left and right sides thereof, and a corresponding feed channel 3 and a discharge channel 4 are fixedly connected to the ultra-low temperature refrigerator 1 at the feed port and the discharge port respectively.

[0042] The conveying mechanism comprises a conveyor belt 5 that passes through the accommodating cavity connected to the ultra-low temperature refrigerator 1, and partitions 6 whose transverse and longitudinal cross-sections are adapted to the feed channel 3 and the discharge channel 4 are fixedly connected to the belt surface of the conveyor belt 5 at intervals, and the distance between two adjacent partitions 6 is less than the length of the feed channel 3 and the discharge channel 4;

[0043] A container 2 is placed on a conveyor belt 5 between two adjacent partitions 6. A corresponding filter plate 7 is fixedly connected to the container 2. A plurality of liquid guide holes 701 with a trapezoidal longitudinal section are distributed on the filter plate 7. A movable plate 9 is movably installed below the filter plate 7 through a corresponding elastic member 8. A protrusion 901 for sealing the liquid guide holes 701 of the filter plate 7 is arranged on the top of the movable plate 9.

[0044] The electromagnet 10 is installed below the feed channel 3. When energized, it is used to adsorb the movable plate 9 to move downward to open the liquid guide hole 701 of the filter plate 7 and form a negative pressure between the movable plate 9 and the filter plate 7; after the movable plate 9 moves down to its proper position, a normal pressure is formed between the movable plate 9 and the filter plate 7 and the containing container 2 is connected up and down.

[0045] The freezing crystallization and solid-liquid separation of the present invention are achieved by a newly designed solid ethoxy pentafluorocyclotriphosphazene treatment device, which directly cools and crystallizes the ethoxy solution through the solid ethoxy pentafluorocyclotriphosphazene treatment device, and performs solid-liquid separation by vacuum filtration separation. Compared with the traditional pouring or filtering separation, the solvent attached to the solid surface can be extracted more cleanly and more comprehensively, and the filtering separation effect is better. The movable plate 9 installed by the corresponding elastic member 8 is abutted on the filter plate 7, so that the protrusion 901 is inserted into the liquid guide hole 701 of the filter plate 7 to form a closure, so that the upper part of the container 2 forms a corresponding receiving area for holding the ethoxy solution, and is automatically transported to the ultra-low temperature refrigerator 1 by the conveyor belt 5 for time-limited freezing crystallization. After the crystallization is completed, it continues to be transmitted outward to the discharge channel 4, and the electromagnet 10 is energized to attract the iron movable plate 9 to move downward. The movable plate 9 is installed with interference fit by fixing corresponding rubber strips around the movable plate 9, so that when the movable plate 9 is pulled downward, a negative pressure similar to that of a syringe is formed between the movable plate 9 and the filter plate 7, so that the solvent attached to the solid surface is extracted and filtered through the filter cloth 11. Compared with the simple filtering and pouring method, the solid-liquid separation effect is more thorough; when the movable plate 9 continues to move downward to the liquid collecting area 201 of the holding container 2, the movable plate 9 is spaced apart from the inner wall of the holding container 2, thereby achieving a pressure relief state so that the separated solvent is diverted to the liquid collecting area 201 for collection and discharged through the drain pipe.

[0046] The cooling crystallization and solid-liquid separation processes can be completed by a set of equipment, which not only improves the automation degree of the process, but also effectively ensures the controllability of the operation process, thereby improving the effect of preparing solid ethoxypentafluorocyclotriphosphazene.

[0047] A corresponding filter cloth 11 is detachably fixedly mounted on the top of the filter plate 7 , and the pore size of the filter cloth 11 is smaller than the pore size of the liquid guide hole 701 , and smaller than the particle size of the solid ethoxypentafluorocyclotriphosphazene after freezing.

[0048] The movable plate 9 is composed of an iron main plate 902 and rubber strips 903 fixedly connected to the edges of the main plate 902. The bottom of the containing container 2 forms a liquid collection area 201 whose width gradually increases from top to bottom. The bottom side of the liquid collection area 201 on the containing container 2 is provided with a drain pipe 12 through a corresponding valve; after the movable plate 9 is moved down to its position, the edge of the movable plate 9 is spaced apart from the inner side wall of the containing container 2 located in the liquid collection area 201.

[0049] The present invention arranges corresponding partitions 6 at intervals on the conveyor belt 5, the transverse and longitudinal sections of the partitions 6 are adapted to the feed channel and the discharge channel 4, and the spacing between two adjacent partitions 6 is smaller than the width of the feed channel and the discharge channel 4. The partitions 6 are arranged to separate and limit the placement of the holding containers 2. More importantly, by setting the cross-section and the distance, it is ensured that no matter how the conveyor belt 5 runs, at least one partition 6 is arranged at the feed channel, and one partition 6 is arranged at the discharge channel 4 to close the feed port and the discharge port, effectively closing the ultra-low temperature refrigerator 1, ensuring the use of the ultra-low temperature refrigerator 1, and improving the use effect; a circle of rubber can also be fixed to the edge of the partition 6, and installed by interference fit, so as to further improve the sealing degree of the partition 6 to the ultra-low temperature refrigerator 1 on the basis of ensuring the transmission of the conveyor belt 5, so as to further improve the practical effect of the present invention.

[0050] The inner and outer ends of the discharge channel 4 are respectively set as a closed area 401 and a buffer area 402. The width of the buffer area 402 of the discharge channel 4 gradually increases from the inside to the outside and is greater than the width of the partition 6. When the holding container 2 moves into the discharge channel 4, the partitions 6 on both sides of the holding container 2 are respectively placed in the closed area 401 and the buffer area 402.

[0051] The discharge channel 4 of the present invention is configured as a closed area 401 and a buffer area 402, and the width of the buffer area 402 of the discharge channel 4 gradually increases from the inside to the outside, and is greater than the width of the partition 6; when the holding container 2 moves into the discharge channel 4, the partitions 6 on both sides of the holding container 2 are respectively placed in the closed area 401 and the buffer area 402, and the partition 6 placed in the closed area 401 can ensure the sealing of the ultra-low temperature refrigerator 1, and effectively prevent the cold air of the ultra-low temperature refrigerator 1 from being drawn out when the holding container 2 is pumping negative pressure filtration, and the partition 6 placed in the buffer area 402 forms a gap with the discharge channel 4, thereby effectively ensuring the negative pressure filtration action of the holding container 2, and further improving the practical effect of the present invention.

[0052] Example 2

[0053] refer to Figure 6 , a method for purifying ethoxy pentafluorocyclotriphosphazene, comprising the following specific steps:

[0054] S1, preparing an ethoxy solution by mixing ethanol and ethoxy pentafluorocyclotriphosphazene in a molar ratio of 15:1;

[0055] S2, placing the ethoxylated solution prepared in step S1 into an ultra-low temperature refrigerator at -60°C for freezing and crystallization for 4 hours;

[0056] S3, performing solid-liquid separation on the frozen ethoxylated solution to obtain solid ethoxylated pentafluorocyclotriphosphazene, and recovering the separated solvent;

[0057] S4, melting the separated solid ethoxypentafluorocyclotriphosphazene at room temperature, repeating steps S1 to S3 for three times to perform sweating process on the melted ethoxypentafluorocyclotriphosphazene, and obtaining ethoxypentafluorocyclotriphosphazene with a purity of 98.63%.

[0058] Example 3

[0059] refer to Figure 6 , a method for purifying ethoxy pentafluorocyclotriphosphazene, comprising the following specific steps:

[0060] S1, preparing an ethoxy solution by mixing ethanol and ethoxy pentafluorocyclotriphosphazene in a molar ratio of 20:1;

[0061] S2, placing the ethoxylated solution prepared in step S1 into an ultra-low temperature refrigerator at -50°C for freezing and crystallization for 5 hours;

[0062] S3, performing solid-liquid separation on the frozen ethoxylated solution to obtain solid ethoxylated pentafluorocyclotriphosphazene, and recovering the separated solvent;

[0063] S4, melting the separated solid ethoxypentafluorocyclotriphosphazene at room temperature, repeating steps S1 to S3 for 5 times to perform sweating process on the melted ethoxypentafluorocyclotriphosphazene, and obtaining ethoxypentafluorocyclotriphosphazene with a purity of 98.52%.

[0064] Example 4

[0065] refer to Figure 6 , a method for purifying ethoxy pentafluorocyclotriphosphazene, comprising the following specific steps:

[0066] S1, preparing an ethoxy solution by mixing ethanol and ethoxy pentafluorocyclotriphosphazene in a molar ratio of 10:1;

[0067] S2, placing the ethoxylated solution prepared in step S1 into an ultra-low temperature refrigerator at -50°C for freezing and crystallization for 6 hours;

[0068] S3, performing solid-liquid separation on the frozen ethoxylated solution to obtain solid ethoxylated pentafluorocyclotriphosphazene, and recovering the separated solvent;

[0069] S4, melting the separated solid ethoxypentafluorocyclotriphosphazene at room temperature, repeating steps S1 to S3 for 5 times to perform sweating process on the melted ethoxypentafluorocyclotriphosphazene, and obtaining ethoxypentafluorocyclotriphosphazene with a purity of 98.85%.

[0070] Example 5

[0071] refer to Figure 6 , a method for purifying ethoxy pentafluorocyclotriphosphazene, comprising the following specific steps:

[0072] S1, preparing an ethoxy solution by mixing ethanol and ethoxy pentafluorocyclotriphosphazene in a molar ratio of 10:1;

[0073] S2, placing the ethoxylated solution prepared in step S1 into an ultra-low temperature refrigerator at -15°C for freezing and crystallization for 7 hours;

[0074] S3, performing solid-liquid separation on the frozen ethoxylated solution to obtain solid ethoxylated pentafluorocyclotriphosphazene, and recovering the separated solvent;

[0075] S4, melting the separated solid ethoxypentafluorocyclotriphosphazene at room temperature, transferring the melted liquid ethoxypentafluorocyclotriphosphazene to a distillation tower, and distilling the solvent under reduced pressure at 3000Pa under nitrogen protection to obtain ethoxypentafluorocyclotriphosphazene with a purity of 99.94%.

[0076] Example 6

[0077] refer to Figure 6 , a method for purifying ethoxy pentafluorocyclotriphosphazene, comprising the following specific steps:

[0078] S1, placing a container containing magnetite, 150L of n-hexane and 26kg of hexafluorocyclotriphosphazene (about 100 mol) in a cold trap of a low-temperature circulation pump and stirring for 10 minutes until a hexafluorocyclotriphosphazene solution is uniformly prepared, and the temperature is set to -10°C; dissolving 8kg of potassium ethoxide (about 120 mol) in 250L of n-hexane to prepare a sodium ethoxide solution, and lowering its temperature to -10°C; adding the potassium ethoxide solution to the hexafluorocyclotriphosphazene solution at a certain rate and stirring to react, ensuring that the temperature displayed by the thermometer is stable at -10°C, the entire dropping process lasts for 1 hour, and after the dropping is completed, continuing the reaction for 4 hours to prepare an ethoxy solution;

[0079] S2, placing the ethoxylated solution prepared in step S1 into an ultra-low temperature refrigerator at -60°C for freezing and crystallization for 4 hours;

[0080] S3, performing solid-liquid separation on the frozen ethoxylated solution to obtain solid ethoxylated pentafluorocyclotriphosphazene, and recovering the separated solvent;

[0081] S4, melting the separated solid ethoxypentafluorocyclotriphosphazene at room temperature, transferring the melted ethoxypentafluorocyclotriphosphazene to a distillation tower, and distilling the solvent under reduced pressure at 3000Pa under nitrogen protection to obtain ethoxypentafluorocyclotriphosphazene with a purity of 99.92%.

[0082] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for purifying ethoxypentafluorocyclotriphosphazene, characterized in that: The specific steps include: S1, preparing an ethoxy solution by mixing an organic solvent with ethoxy pentafluorocyclotriphosphazene; S2, placing the prepared ethoxylated solution into an ultra-low temperature refrigerator at -80°C to 0°C for freezing and crystallization, with a freezing time of 1 to 8 hours; S3, performing solid-liquid separation on the frozen ethoxylated solution to obtain solid ethoxylated pentafluorocyclotriphosphazene; S4, melting the separated solid ethoxypentafluorocyclotriphosphazene at room temperature, repeating steps S1 to S3 for the melted ethoxypentafluorocyclotriphosphazene to perform a sweating process, so that the purity of the ethoxypentafluorocyclotriphosphazene reaches more than 98%.

2. The method for purifying ethoxypentafluorocyclotriphosphazene according to claim 1, characterized in that: The organic solvent in step S1 is one or more of acetonitrile, n-hexane, ethanol, and cyclohexane.

3. The method for purifying ethoxypentafluorocyclotriphosphazene according to claim 1, characterized in that: The molar ratio of ethoxypentafluorocyclotriphosphazene to the organic solvent in step S1 is 1:1 to 1:

20.

4. The method for purifying ethoxypentafluorocyclotriphosphazene according to claim 1, characterized in that: In the step S3, the frozen ethoxylated solution is separated into solid and liquid by pouring or filtering, and the separated solvent is recovered.

5. The method for purifying ethoxypentafluorocyclotriphosphazene according to claim 1, characterized in that: The freezing crystallization of step S2 and the solid-liquid separation of step S3 of the method are achieved by solid ethoxy pentafluorocyclotriphosphazene processing equipment, and the solid ethoxy pentafluorocyclotriphosphazene processing equipment comprises: An ultra-low temperature refrigerator, wherein a receiving cavity for placing a container is provided in the middle of the ultra-low temperature refrigerator, and a feed port and a discharge port communicating with the receiving cavity are provided on the left and right sides thereof, and corresponding feed channels and discharge channels are fixedly connected to the ultra-low temperature refrigerator at the feed port and the discharge port respectively; The conveying mechanism comprises a conveyor belt penetrating through the accommodating cavity connected to the ultra-low temperature refrigerator, and the belt surface of the conveyor belt is fixed with partitions whose transverse and longitudinal cross-sections are adapted to the feed channel and the discharge channel at intervals, and the distance between two adjacent partitions is less than the length of the feed channel and the discharge channel; A containing container is placed on the conveyor belt between two adjacent partitions, wherein a corresponding filter plate is fixedly connected in the containing container, and a plurality of liquid guide holes with a trapezoidal longitudinal section are distributed on the filter plate, and a movable plate is movably installed below the filter plate through a corresponding elastic member, and a protrusion for sealing the liquid guide holes of the filter plate is arranged on the top of the movable plate; The electromagnet is installed below the feed channel and is used to adsorb the movable plate to move downward to open the liquid guide hole of the filter plate and form a negative pressure between the movable plate and the filter plate when energized; after the movable plate moves down to its proper position, a normal pressure is formed between the movable plate and the filter plate and the containing container is connected up and down.

6. The method for purifying ethoxypentafluorocyclotriphosphazene according to claim 5, characterized in that: A corresponding filter cloth is detachably fixedly mounted above the filter plate, and the pore size of the filter cloth is smaller than the pore size of the liquid guide hole and smaller than the particle size of the solid ethoxy pentafluorocyclotriphosphazene after freezing.

7. The method for purifying ethoxypentafluorocyclotriphosphazene according to claim 6, characterized in that: The movable plate is composed of an iron main body plate and rubber strips fixedly connected to the edges of the main body plate. The bottom of the containing container forms a liquid collection area with a width that gradually increases from top to bottom. After the movable plate moves down to its position, a distance is set between the edge of the movable plate and the inner side wall of the containing container located in the liquid collection area.

8. The method for purifying ethoxypentafluorocyclotriphosphazene according to claim 7, characterized in that: The inner and outer ends of the discharge channel are respectively set as a closed area and a buffer zone, and the width of the buffer zone of the discharge channel gradually increases from the inside to the outside and is greater than the width of the partition plate; when the holding container moves into the discharge channel, the partition plates on both sides of the holding container are respectively placed in the closed area and the buffer zone.

9. The method for purifying ethoxypentafluorocyclotriphosphazene according to claim 1, characterized in that: The sweating process in step S4 can be carried out by a distillation method, wherein the distillation process needs to be carried out under the protection of a corresponding inert gas.

10. The method for purifying ethoxypentafluorocyclotriphosphazene according to claim 9, characterized in that: The inert gas is one of nitrogen, helium or argon.

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