A continuous production process of liquid lithium hexafluorophosphate

Abstract

The present invention discloses a continuous production process of liquid lithium hexafluorophosphate, and relates to the technical field of lithium ion battery electrolyte. The whole process of this process is carried out under nitrogen sealing conditions. After liquid anhydrous hydrogen fluoride and liquid chlorine are introduced into a microchannel mixer for mixing, they are introduced into a primary tubular reactor together with phosphorus trichloride liquid for reaction, and the generated gas is introduced into a gas-liquid separator and a condenser to obtain phosphorus pentafluoride gas, which is continuously introduced into a secondary tubular reactor to react with a lithium fluoride solution to generate an unsaturated solution of lithium hexafluorophosphate; the generated lithium hexafluorophosphate solution is adsorbed by a trifluoromethyl hydrogen type macroporous cationic resin, the trifluoromethyl hydrogen type macroporous cationic resin is filtered to remove, the filtrate is crystallized and dried, and the dried lithium hexafluorophosphate crystals are prepared as liquid lithium hexafluorophosphate. This process realizes the continuous production of liquid lithium hexafluorophosphate, improves the safety in the production process, effectively improves the product quality, and meets policy requirements.

Description

Technical Field

[0001] The invention relates to the technical field of lithium ion battery electrolyte, in particular to a continuous production process of liquid lithium hexafluorophosphate. Background Art

[0002] As a key component of lithium-ion battery electrolyte, lithium hexafluorophosphate (LiPF6) is widely used in new energy vehicles, energy storage devices, portable electronic products and other fields due to its excellent conductivity and chemical stability. With the increase in global demand for clean energy, the lithium-ion battery industry has developed rapidly, and the market demand for high-purity lithium hexafluorophosphate is growing. However, the traditional lithium hexafluorophosphate production process has many challenges, which limits the further improvement of product quality and large-scale application.

[0003] Patent document: A preparation process of lithium hexafluorophosphate (publication number: CN115285963A), the preparation process comprising the following steps: step 1: prepare hydrogen fluoride, lithium fluoride and phosphorus pentafluoride gas respectively according to a fixed ratio; step 2: use anhydrous acetonitrile as a solvent, and mix with high-purity lithium fluoride under anhydrous and sealed conditions; step 3: add phosphorus pentafluoride gas to a reaction container, the phosphorus pentafluoride gas reacts with lithium fluoride, and when the external pressure gauge shows that the pressure of the phosphorus pentafluoride gas in the container is no longer reduced, the reaction is terminated, and a solid precipitate is generated at this time; step 4: filter the internal precipitate, and then vacuum dry it to obtain a crude lithium hexafluorophosphate product; step 5: purify the crude lithium hexafluorophosphate product.

[0004] The traditional lithium hexafluorophosphate production process mainly adopts intermittent reaction. The specific process includes the reaction of hydrogen fluoride and phosphorus pentachloride to form an intermediate, which is then reacted with lithium fluoride to form lithium hexafluorophosphate. This process has problems such as complex reaction process, high energy consumption, and unstable product purity. In addition, the intermittent reaction production process often requires a lot of manual operation, which does not meet policy requirements; and manual operation makes the product quality fluctuate greatly, making it difficult to stably produce high-purity lithium hexafluorophosphate, and it is also difficult to achieve precise control of crystal particle size.

[0005] To meet the above challenges, researchers have tried to develop new production processes, such as continuous production. However, the continuous production technologies currently on the market generally have problems such as complex equipment, difficult operation, and high costs. It is also difficult to ensure high purity and stability of the product while ensuring high yield. Therefore, there is an urgent need for a production process that can improve the purity of lithium hexafluorophosphate, optimize the particle size distribution, and be safer and more efficient to meet the market's growing demand for high-performance lithium battery materials. Summary of the invention

[0006] A continuous production process of liquid lithium hexafluorophosphate, the whole process is carried out under nitrogen sealing conditions, and the operating steps are:

[0007] a. The liquid anhydrous hydrogen fluoride and liquid chlorine are continuously introduced into the microchannel mixer in a certain proportion for mixing;

[0008] b. The mixed solution and phosphorus trichloride liquid are continuously introduced into a primary tubular reactor in a certain ratio to react to generate phosphorus pentafluoride and hydrogen chloride, the reaction temperature is controlled, and the generated gas is introduced into a gas-liquid separator and a condenser to obtain phosphorus pentafluoride gas;

[0009] c. The phosphorus pentafluoride gas is continuously introduced into a secondary tubular reactor to react with the lithium fluoride solution to form an unsaturated solution of lithium hexafluorophosphate;

[0010] d. After the generated unsaturated lithium hexafluorophosphate solution is adsorbed by a trifluoromethyl hydrogen macroporous cationic resin, the trifluoromethyl hydrogen macroporous cationic resin is removed by filtration, the filtrate is crystallized and dried, and the dried lithium hexafluorophosphate crystals are prepared as liquid lithium hexafluorophosphate.

[0011] As a preferred technical solution of the present invention, the molar ratio of liquid chlorine to liquid anhydrous hydrogen fluoride in step a is 1:17-30.

[0012] As a preferred technical solution of the present invention, the molar ratio of the phosphorus trichloride liquid to the mixed solution in step b is 1:18-30.

[0013] As a preferred technical solution of the present invention, the reaction temperature in step b is controlled between -15°C and 15°C.

[0014] As a preferred technical solution of the present invention, the lithium fluoride solution in step c is a suspension solution of lithium fluoride dissolved in anhydrous hydrogen fluoride, and its concentration is 4%-8%.

[0015] As a preferred technical solution of the present invention, the reaction conditions in step c are: temperature -5-15°C, pressure <0.1MPa.

[0016] As a preferred technical solution of the present invention, nitrogen is continuously introduced during the drying process in step d, the material of the part of the equipment that is in direct contact with the material is 316L, and the drying temperature does not exceed 100°C.

[0017] As a preferred technical solution of the present invention, the amount of the trifluoromethyl hydrogen type macroporous cationic resin is 5-12% of the mass of lithium hexafluorophosphate, and the preparation method thereof is:

[0018] T1: Acylation reaction:

[0019] First, 120-180 parts of sodium macroporous cationic resin are taken and soaked in 800-1500 parts of tetrahydrofuran solvent, and then 10-15 parts of methacryloyl chloride and 3-6 parts of aluminum chloride are added, the temperature of the reaction system is controlled at -10 to 5°C, and stirring is continued for 18-24 hours. After the reaction is completed, filtering and drying are performed to obtain acryl cationic resin;

[0020] T2: UV-induced photochemical reaction:

[0021] Then, the acrylic cationic resin is placed in a photochemical reactor, a modified gas is introduced, and an ultraviolet light source is used to irradiate the resin at room temperature for 30-70 minutes to introduce functional groups through photochemical action. After the treatment, the resin is filtered and dried to obtain a sodium trifluoromethyl type macroporous cationic resin.

[0022] T3: Transform the sodium trifluoromethyl macroporous cationic resin into the hydrogen type, wash with pure water until no chloride ions are detected, and obtain the trifluoromethyl hydrogen type macroporous cationic resin.

[0023] As a preferred technical solution of the present invention, the wavelength of the ultraviolet light source is selected in the range of 250-350 nm;

[0024] As a preferred technical solution of the present invention, the modified gas is 6-[(trifluoromethyl)mercapto]pyridin-3-amine, CAS: 1153767-25-9, and the volume ratio of steam to ammonia is 1:0.2-0.5; the modified gas flow rate is maintained at 25-50 ml / min;

[0025] The preparation mechanism of the above trifluoromethyl hydrogen type macroporous cationic resin is as follows:

[0026] In the photochemical reactor, the acryl cationic resin generates active intermediates under the irradiation of ultraviolet light source. In this process, the introduced modified gas contains 6-[(trifluoromethyl)mercapto]pyridine-3-amine, which reacts with the active intermediate. The core of this step is the mercapto-propenyl addition reaction, in which the amine group of 6-[(trifluoromethyl)mercapto]pyridine-3-amine reacts with the propenyl group in the resin to form a stable product, and finally obtains a functional trifluoromethyl hydrogen-type macroporous cationic resin.

[0027] By introducing 6-[(trifluoromethyl)mercapto]pyridine-3-amine through this photochemical action and carrying out an amino-propylene addition reaction, the obtained trifluoromethyl hydrogen-type macroporous cationic resin has a significant technical effect. Due to the introduction of the trifluoromethyl functional group, the resin shows excellent performance in purifying and adsorbing impurities in lithium hexafluorophosphate liquid. The trifluoromethyl functional group increases the hydrophobicity of the resin, giving it higher selectivity and affinity for impurities during the adsorption process. In addition, the resin also exhibits excellent tolerance to hydrogen fluoride, which is mainly due to the strong electron attraction effect of the trifluoromethyl group and its stabilizing effect on the resin structure, thereby ensuring the stability and service life of the resin in a hydrogen fluoride environment.

[0028] Technical effects:

[0029] Compared with traditional methods, this method has the following advantages:

[0030] 1. The continuous production of liquid lithium hexafluorophosphate has been realized, the safety of the production process has been improved, and the product quality has been effectively improved, which meets the policy requirements;

[0031] 2. Realize particle size classification, which can effectively control the particle size of lithium hexafluorophosphate crystals within the required range;

[0032] 3. Compared with the traditional process, this process is simpler to operate, requires less equipment investment, and reduces labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is the chromatogram of Comparative Example 2 of the present invention.

[0034] Figure 2 This is the chromatogram of Example 1 of the present invention. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0036] Example 1

[0037] A continuous production process of liquid lithium hexafluorophosphate, the whole process is carried out under nitrogen sealing conditions, and the operating steps are:

[0038] a. The liquid anhydrous hydrogen fluoride and liquid chlorine are continuously introduced into the microchannel mixer in a certain proportion for mixing;

[0039] b. The mixed solution and phosphorus trichloride liquid are continuously introduced into a primary tubular reactor in a certain ratio to react to generate phosphorus pentafluoride and hydrogen chloride, the reaction temperature is controlled, and the generated gas is introduced into a gas-liquid separator and a condenser to obtain phosphorus pentafluoride gas;

[0040] c. The phosphorus pentafluoride gas is continuously introduced into a secondary tubular reactor to react with the lithium fluoride solution to form an unsaturated solution of lithium hexafluorophosphate;

[0041] d. After the generated unsaturated lithium hexafluorophosphate solution is adsorbed by a trifluoromethyl hydrogen macroporous cationic resin, the trifluoromethyl hydrogen macroporous cationic resin is removed by filtration, the filtrate is crystallized and dried, and the dried lithium hexafluorophosphate crystals are prepared as liquid lithium hexafluorophosphate.

[0042] The molar ratio of liquid chlorine to liquid anhydrous hydrogen fluoride in step a is 1:17.

[0043] In the step b, the molar ratio of the phosphorus trichloride liquid to the mixed solution is 1:18.

[0044] In the step b, the reaction temperature is controlled at -15°C.

[0045] The lithium fluoride solution in step c is a suspension solution of lithium fluoride dissolved in anhydrous hydrogen fluoride, and its concentration is 4%.

[0046] The reaction conditions in step c are: temperature -5°C, pressure <0.1 MPa.

[0047] In the step d, nitrogen is continuously introduced during the drying process, the material of the part of the equipment that is in direct contact with the material is 316L, and the drying temperature does not exceed 100°C.

[0048] The amount of the trifluoromethyl hydrogen type macroporous cationic resin is 5% of the mass of lithium hexafluorophosphate, and the preparation method thereof is as follows:

[0049] T1: Acylation reaction:

[0050] First, 120 g of sodium macroporous cationic resin was taken and soaked in 800 g of tetrahydrofuran solvent, followed by adding 10 g of methacryloyl chloride and 3 g of aluminum chloride, the temperature of the reaction system was controlled at -10 ° C, and stirring was continued for 18 hours. After the reaction was completed, it was filtered and dried to obtain acryl cationic resin;

[0051] T2: UV-induced photochemical reaction:

[0052] Then, the acrylic cationic resin is placed in a photochemical reactor, a modified gas is introduced, and an ultraviolet light source is used to irradiate the resin at room temperature for 30 minutes to introduce functional groups through photochemical action. After the treatment, the resin is filtered and dried to obtain a sodium trifluoromethyl type macroporous cationic resin.

[0053] T3: Transform the sodium trifluoromethyl macroporous cationic resin into the hydrogen type, wash with pure water until no chloride ions are detected, and obtain the trifluoromethyl hydrogen type macroporous cationic resin.

[0054] The wavelength of the ultraviolet light source is selected in the range of 250nm;

[0055] The modified gas is 6-[(trifluoromethyl)mercapto]pyridin-3-amine, CAS: 1153767-25-9, the volume ratio of steam to ammonia is 1:0.2; the modified gas flow rate is maintained at 25 ml / min;

[0056] Example 2

[0057] A continuous production process of liquid lithium hexafluorophosphate, the whole process is carried out under nitrogen sealing conditions, and the operating steps are:

[0058] a. The liquid anhydrous hydrogen fluoride and liquid chlorine are continuously introduced into the microchannel mixer in a certain proportion for mixing;

[0059] b. The mixed solution and phosphorus trichloride liquid are continuously introduced into a primary tubular reactor in a certain ratio to react to generate phosphorus pentafluoride and hydrogen chloride, the reaction temperature is controlled, and the generated gas is introduced into a gas-liquid separator and a condenser to obtain phosphorus pentafluoride gas;

[0060] c. The phosphorus pentafluoride gas is continuously introduced into a secondary tubular reactor to react with the lithium fluoride solution to form an unsaturated solution of lithium hexafluorophosphate;

[0061] d. After the generated unsaturated lithium hexafluorophosphate solution is adsorbed by a trifluoromethyl hydrogen macroporous cationic resin, the trifluoromethyl hydrogen macroporous cationic resin is removed by filtration, the filtrate is crystallized and dried, and the dried lithium hexafluorophosphate crystals are prepared as liquid lithium hexafluorophosphate.

[0062] The molar ratio of liquid chlorine to liquid anhydrous hydrogen fluoride in step a is 1:21.

[0063] In the step b, the molar ratio of the phosphorus trichloride liquid to the mixed solution is 1:22.

[0064] In the step b, the reaction temperature is controlled at 0°C.

[0065] The lithium fluoride solution in step c is a suspension solution of lithium fluoride dissolved in anhydrous hydrogen fluoride, and its concentration is 6%.

[0066] The reaction conditions in step c are: temperature 0°C and pressure <0.1 MPa.

[0067] In the step d, nitrogen is continuously introduced during the drying process, the material of the part of the equipment that is in direct contact with the material is 316L, and the drying temperature does not exceed 100°C.

[0068] The amount of the trifluoromethyl hydrogen type macroporous cationic resin is 7% of the mass of lithium hexafluorophosphate, and the preparation method thereof is as follows:

[0069] T1: Acylation reaction:

[0070] First, 140 g of sodium macroporous cationic resin was taken and soaked in 1000 g of tetrahydrofuran solvent, followed by adding 12 g of methacryloyl chloride and 4 g of aluminum chloride, the temperature of the reaction system was controlled at -5 ° C, and stirring was continued for 20 hours. After the reaction was completed, it was filtered and dried to obtain acryl cationic resin;

[0071] T2: UV-induced photochemical reaction:

[0072] Then, the acrylic cationic resin is placed in a photochemical reactor, a modified gas is introduced, and an ultraviolet light source is used to irradiate at room temperature for 45 minutes to introduce functional groups through photochemical action. After the treatment, the resin is filtered and dried to obtain a sodium trifluoromethyl type macroporous cationic resin;

[0073] T3: Transform the sodium trifluoromethyl macroporous cationic resin into the hydrogen type, wash with pure water until no chloride ions are detected, and obtain the trifluoromethyl hydrogen type macroporous cationic resin.

[0074] The wavelength of the ultraviolet light source is selected in the range of 300 nm;

[0075] The modified gas is 6-[(trifluoromethyl)mercapto]pyridin-3-amine, CAS: 1153767-25-9, the volume ratio of steam to ammonia is 1:0.3; the modified gas flow rate is maintained at 35 ml / min;

[0076] Example 3

[0077] A continuous production process of liquid lithium hexafluorophosphate, the whole process is carried out under nitrogen sealing conditions, and the operating steps are:

[0078] a. The liquid anhydrous hydrogen fluoride and liquid chlorine are continuously introduced into the microchannel mixer in a certain proportion for mixing;

[0079] b. The mixed solution and phosphorus trichloride liquid are continuously introduced into a primary tubular reactor in a certain ratio to react to generate phosphorus pentafluoride and hydrogen chloride, the reaction temperature is controlled, and the generated gas is introduced into a gas-liquid separator and a condenser to obtain phosphorus pentafluoride gas;

[0080] c. The phosphorus pentafluoride gas is continuously introduced into a secondary tubular reactor to react with the lithium fluoride solution to form an unsaturated solution of lithium hexafluorophosphate;

[0081] d. After the generated unsaturated lithium hexafluorophosphate solution is adsorbed by a trifluoromethyl hydrogen macroporous cationic resin, the trifluoromethyl hydrogen macroporous cationic resin is removed by filtration, the filtrate is crystallized and dried, and the dried lithium hexafluorophosphate crystals are prepared as liquid lithium hexafluorophosphate.

[0082] The molar ratio of liquid chlorine to liquid anhydrous hydrogen fluoride in step a is 1:26.

[0083] In the step b, the molar ratio of the phosphorus trichloride liquid to the mixed solution is 1:25.

[0084] In the step b, the reaction temperature is controlled at 0°C.

[0085] The lithium fluoride solution in step c is a suspension solution of lithium fluoride dissolved in anhydrous hydrogen fluoride, and its concentration is 6%.

[0086] The reaction conditions in step c are: temperature 5° C., pressure <0.1 MPa.

[0087] In the step d, nitrogen is continuously introduced during the drying process, the material of the part of the equipment that is in direct contact with the material is 316L, and the drying temperature does not exceed 100°C.

[0088] The amount of the trifluoromethyl hydrogen type macroporous cationic resin is 9% of the mass of lithium hexafluorophosphate, and the preparation method thereof is as follows:

[0089] T1: Acylation reaction:

[0090] First, 160 g of sodium macroporous cationic resin was taken and soaked in 1200 g of tetrahydrofuran solvent, followed by adding 14 g of methacryloyl chloride and 5 g of aluminum chloride, the temperature of the reaction system was controlled at 0°C, and stirring was continued for 22 hours. After the reaction was completed, the reaction was filtered and dried to obtain acryl cationic resin;

[0091] T2: UV-induced photochemical reaction:

[0092] Then, the acrylic cationic resin is placed in a photochemical reactor, a modified gas is introduced, and an ultraviolet light source is used to irradiate the resin at room temperature for 60 minutes to introduce functional groups through photochemical action. After the treatment, the resin is filtered and dried to obtain a sodium trifluoromethyl type macroporous cationic resin.

[0093] T3: Transform the sodium trifluoromethyl macroporous cationic resin into the hydrogen type, wash with pure water until no chloride ions are detected, and obtain the trifluoromethyl hydrogen type macroporous cationic resin.

[0094] The wavelength of the ultraviolet light source is selected in the range of 300 nm;

[0095] The modified gas is 6-[(trifluoromethyl)mercapto]pyridin-3-amine, CAS: 1153767-25-9, the volume ratio of steam to ammonia is 1:0.4; the modified gas flow rate is maintained at 45 ml / min;

[0096] Example 4

[0097] A continuous production process of liquid lithium hexafluorophosphate, the whole process is carried out under nitrogen sealing conditions, and the operating steps are:

[0098] a. The liquid anhydrous hydrogen fluoride and liquid chlorine are continuously introduced into the microchannel mixer in a certain proportion for mixing;

[0099] b. The mixed solution and phosphorus trichloride liquid are continuously introduced into a primary tubular reactor in a certain ratio to react to generate phosphorus pentafluoride and hydrogen chloride, the reaction temperature is controlled, and the generated gas is introduced into a gas-liquid separator and a condenser to obtain phosphorus pentafluoride gas;

[0100] c. The phosphorus pentafluoride gas is continuously introduced into a secondary tubular reactor to react with the lithium fluoride solution to form an unsaturated solution of lithium hexafluorophosphate;

[0101] d. After the generated unsaturated lithium hexafluorophosphate solution is adsorbed by a trifluoromethyl hydrogen macroporous cationic resin, the trifluoromethyl hydrogen macroporous cationic resin is removed by filtration, the filtrate is crystallized and dried, and the dried lithium hexafluorophosphate crystals are prepared as liquid lithium hexafluorophosphate.

[0102] The molar ratio of liquid chlorine to liquid anhydrous hydrogen fluoride in step a is 1:30.

[0103] In the step b, the molar ratio of the phosphorus trichloride liquid to the mixed solution is 1:30.

[0104] In the step b, the reaction temperature is controlled at 15°C.

[0105] The lithium fluoride solution in step c is a suspension solution of lithium fluoride dissolved in anhydrous hydrogen fluoride, and its concentration is 8%.

[0106] The reaction conditions in step c are: temperature 15° C., pressure <0.1 MPa.

[0107] In the drying process of step d, nitrogen is continuously introduced, the material of the part of the equipment in direct contact with the material is 316L, and the drying temperature does not exceed 100°C. The amount of the trifluoromethyl hydrogen type macroporous cationic resin is 12% of the mass of lithium hexafluorophosphate, and its preparation method is:

[0108] T1: Acylation reaction:

[0109] First, 180 g of sodium macroporous cationic resin was taken and soaked in 1500 g of tetrahydrofuran solvent, followed by adding 15 g of methacryloyl chloride and 6 g of aluminum chloride, the temperature of the reaction system was controlled at 5° C., and stirring was continued for 24 hours. After the reaction was completed, the reaction was filtered and dried to obtain an propylene cationic resin;

[0110] T2: UV-induced photochemical reaction:

[0111] Then, the acrylic cationic resin is placed in a photochemical reactor, a modified gas is introduced, and an ultraviolet light source is used to irradiate the resin at room temperature for 70 minutes to introduce functional groups through photochemical action. After the treatment, the resin is filtered and dried to obtain a sodium trifluoromethyl type macroporous cationic resin.

[0112] T3: Transform the sodium trifluoromethyl macroporous cationic resin into the hydrogen type, wash with pure water until no chloride ions are detected, and obtain the trifluoromethyl hydrogen type macroporous cationic resin.

[0113] The wavelength of the ultraviolet light source is selected in the range of 350 nm;

[0114] The modified gas is 6-[(trifluoromethyl)mercapto]pyridin-3-amine, CAS: 1153767-25-9, the volume ratio of steam to ammonia is 1:0.5; the modified gas flow rate is maintained at 50 ml / min;

[0115] Comparative Example 1

[0116] This example is the same as Example 1 except that trifluoromethyl hydrogen macroporous cationic resin is not used for adsorption filtration. This example is a comparative example of Example 1.

[0117] Comparative Example 2

[0118] This example is the same as Example 1 except that methacryloyl chloride is not added during the preparation of trifluoromethyl hydrogen-type macroporous cationic resin. This example is a comparative example of Example 1.

[0119] Comparative Example 3

[0120] This example is the same as Example 1 except that 6-[(trifluoromethyl)mercapto]pyridin-3-amine is not added during the preparation of the trifluoromethyl hydrogen-type macroporous cationic resin. This example is a comparative example of Example 1.

[0121] Example detection

[0122] 1. High performance liquid chromatography (HPLC): used to detect the purity of lithium hexafluorophosphate, especially the content of its main component;

[0123] 2. Laser particle size analyzer: used to measure the particle size distribution of lithium hexafluorophosphate particles and provide data on average particle size and particle size range;

[0124] 3. Karl Fischer titration: Determine the water content in the sample by chemical titration.

[0125] Example test results:

[0126] Lithium hexafluorophosphate purity% Lithium hexafluorophosphate particles D50 Moisture content Example 1 99.990 80μm 13ppm Example 2 99.992 73μm 8ppm Example 3 99.995 67μm 5ppm Example 4 99.996 70μm 6ppm Comparative Example 1 96.751 92μm 58ppm Comparative Example 2 99.979 87μm 18ppm Comparative Example 3 99.836 85μm 23ppm

[0127] Through the above-mentioned testing scheme, the effectiveness of the continuous production process can be fully verified to ensure that the liquid lithium hexafluorophosphate product has excellent properties such as high purity, good particle size control, and low water content.

[0128] The applicant declares that the present invention is further illustrated by the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A continuous production process of liquid lithium hexafluorophosphate, characterized in that: The whole process is carried out under nitrogen sealing conditions, and the operating steps are as follows: a. The liquid anhydrous hydrogen fluoride and liquid chlorine are continuously introduced into the microchannel mixer in a certain proportion for mixing; b. The mixed solution and phosphorus trichloride liquid are continuously introduced into a primary tubular reactor in a certain ratio to react to generate phosphorus pentafluoride and hydrogen chloride, the reaction temperature is controlled, and the generated gas is introduced into a gas-liquid separator and a condenser to obtain phosphorus pentafluoride gas; c. The phosphorus pentafluoride gas is continuously introduced into a secondary tubular reactor to react with the lithium fluoride solution to form an unsaturated solution of lithium hexafluorophosphate; d. After the unsaturated lithium hexafluorophosphate solution is adsorbed by a trifluoromethyl hydrogen macroporous cationic resin, the trifluoromethyl hydrogen macroporous cationic resin is removed by filtration, the filtrate is crystallized and dried, and the dried lithium hexafluorophosphate crystals are prepared as liquid lithium hexafluorophosphate; The trifluoromethyl hydrogen type macroporous cationic resin is used in an amount of 5-12% of the mass of lithium hexafluorophosphate, and its preparation method is as follows: T1: Acylation reaction: According to the mass fraction, first, 120-180 parts of sodium-type macroporous cationic resin are taken and immersed in 800-1500 parts of tetrahydrofuran solvent, and then 10-15 parts of methacryloyl chloride and 3-6 parts of aluminum chloride are added, the temperature of the reaction system is controlled at -10 to 5°C, and stirring is continued for 18-24 hours. After the reaction is completed, it is filtered and dried to obtain acryl cationic resin; T2: UV-induced photochemical reaction: Then, the acrylic cationic resin is placed in a photochemical reactor, a modified gas is introduced, and an ultraviolet light source is used to irradiate the resin at room temperature for 30-70 minutes to introduce functional groups through photochemical action. After the treatment, the resin is filtered and dried to obtain a sodium trifluoromethyl type macroporous cationic resin. T3: converting the trifluoromethyl sodium macroporous cationic resin into the hydrogen type, washing with pure water until no chloride ions are detected, and obtaining the trifluoromethyl hydrogen macroporous cationic resin; The modified gas is a mixed gas of 6-[(trifluoromethyl)mercapto]pyridine-3-amine steam and ammonia.

2. A continuous production process of liquid lithium hexafluorophosphate according to claim 1, characterized in that: The molar ratio of liquid chlorine to liquid anhydrous hydrogen fluoride in step a is 1:17-30.

3. A continuous production process of liquid lithium hexafluorophosphate according to claim 1, characterized in that: In the step b, the molar ratio of the phosphorus trichloride liquid to the mixed solution is 1:18-30.

4. A continuous production process of liquid lithium hexafluorophosphate according to claim 1, characterized in that: In the step b, the reaction temperature is controlled between -15°C and 15°C.

5. A continuous production process of liquid lithium hexafluorophosphate according to claim 1, characterized in that: The lithium fluoride solution in step c is a suspension solution of lithium fluoride dissolved in anhydrous hydrogen fluoride, and its mass concentration is 4%-8%.

6. A continuous production process of liquid lithium hexafluorophosphate according to claim 1, characterized in that: The reaction conditions in step c are: temperature -5-15°C, pressure <0.1 MPa.

7. A continuous production process of liquid lithium hexafluorophosphate according to claim 1, characterized in that: In the step d, nitrogen is continuously introduced during the drying process, the material of the part of the equipment that is in direct contact with the material is 316L, and the drying temperature does not exceed 100°C.

8. A continuous production process of liquid lithium hexafluorophosphate according to claim 1, characterized in that: The wavelength of the ultraviolet light source is selected in the range of 250-350 nm.

9. A continuous production process of liquid lithium hexafluorophosphate according to claim 1, characterized in that: The volume ratio of the 6-[(trifluoromethyl)mercapto]pyridine-3-amine vapor and ammonia mixed gas is 1:0.2-0.5; the flow rate of the modified gas is maintained at 25-50 ml / min.

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