CN-121990534-A - Preparation method of hexafluorophosphoric acid

Abstract

The invention provides a preparation method of hexafluorophosphoric acid, which comprises the following steps of mixing an oxygen-containing phosphorus compound with anhydrous hydrogen fluoride, and reacting at the temperature of 65-100 ℃ under the pressure of not less than 0.4Mpa to obtain the hexafluorophosphoric acid. The preparation method can obviously improve the yield of hexafluorophosphoric acid.

Inventors

• QIN XIAOKANG
• Liu du
• YANG SHUWU
• HONG GUO

Assignees

• 九江天赐高新材料有限公司

Dates

Publication Date

20260508

Application Date

20241105

Claims (10)

1. 1. A method for preparing hexafluorophosphoric acid, comprising the steps of: Mixing an oxygen-containing phosphorus compound with anhydrous hydrogen fluoride, and reacting at the temperature of 65-100 ℃ and the pressure of not lower than 0.4Mpa to obtain the hexafluorophosphoric acid.
2. 2. The method for producing hexafluorophosphoric acid according to claim 1, wherein the reaction temperature is 65 to 85 ℃ and/or the reaction time is 0.5 to 2 hours.
3. 3. The method for producing hexafluorophosphoric acid according to claim 1 or 2, wherein the pressure in the reaction is 0.4 to 1.5mpa.
4. 4. A method for producing hexafluorophosphoric acid as claimed in any one of claims 1 to 3, wherein said oxygen-containing phosphorus compound comprises at least one of polyphosphoric acid, anhydrous phosphoric acid, phosphorus pentoxide.
5. 5. The method for producing hexafluorophosphoric acid according to claim 4, wherein the molar ratio of said polyphosphoric acid to said anhydrous hydrogen fluoride is 1 (26.4 to 48.0).
6. 6. The method for producing hexafluorophosphoric acid according to claim 4, wherein the molar ratio of the anhydrous phosphoric acid to the anhydrous hydrogen fluoride is 1 (6.6 to 12.0).
7. 7. The method for producing hexafluorophosphoric acid according to claim 4, wherein the molar ratio of phosphorus pentoxide to anhydrous hydrogen fluoride is 1 (13.2 to 24.0).
8. 8. The method for producing hexafluorophosphoric acid as claimed in claim 4, wherein the oxygen-containing phosphorus compound is polyphosphoric acid; The molar ratio of the polyphosphoric acid to the anhydrous hydrogen fluoride is 1 (26.4-36.0).
9. 9. The method for producing hexafluorophosphoric acid as claimed in any one of claims 1 to 8, wherein after the completion of the reaction, the reaction system is cooled to-10 to 20 ℃ and replaced with nitrogen gas to obtain hexafluorophosphoric acid.
10. 10. The method for producing hexafluorophosphoric acid according to claim 9, wherein the mixture obtained by the displacement is condensed and the product at-20 to 5 ℃ is collected to obtain the recovered hydrogen fluoride.

Description

Preparation method of hexafluorophosphoric acid Technical Field The invention belongs to the technical field of battery material preparation, and particularly relates to a preparation method of hexafluorophosphoric acid. Background The electrolyte, which is one of four key materials of the secondary battery, has a great influence on the electrochemical performance of the battery, and is called "blood" of the secondary battery. Among them, an electrolyte salt is one of important components of an electrolyte solution, and hexafluorophosphate is widely used in current commercial secondary batteries because it can improve battery energy density and electrochemical performance, and also has excellent chemical stability and thermal stability. The existing hexafluorophosphate preparation method is more, and hexafluorophosphoric acid is obtained by reacting an oxygen-containing phosphorus compound with anhydrous hydrogen fluoride, but the yield of the method is lower. Therefore, it is necessary to study a method for producing hexafluorophosphoric acid with high yield. Disclosure of Invention Aiming at the defects, the invention provides a preparation method of hexafluorophosphoric acid, which can obviously improve the yield of hexafluorophosphoric acid. The invention provides a preparation method of hexafluorophosphoric acid, which comprises the following steps: Mixing an oxygen-containing phosphorus compound with anhydrous hydrogen fluoride, and reacting at the temperature of 65-100 ℃ and the pressure of not lower than 0.4Mpa to obtain hexafluorophosphoric acid. Further, the reaction temperature is 65-85 ℃ and/or the reaction time is 0.5-2 h. Further, the pressure in the reaction is 0.4-1.5 mpa. Further, the oxygen-containing phosphorus compound comprises at least one of polyphosphoric acid, anhydrous phosphoric acid and phosphorus pentoxide. Further, the molar ratio of the polyphosphoric acid to the anhydrous hydrogen fluoride is 1 (26.4-48.0). Further, the molar ratio of the anhydrous phosphoric acid to the anhydrous hydrogen fluoride is 1 (6.6-12.0). Further, the molar ratio of the phosphorus pentoxide to the anhydrous hydrogen fluoride is 1 (13.2-24.0). Further, the oxygen-containing phosphorus compound is polyphosphoric acid; The molar ratio of the polyphosphoric acid to the anhydrous hydrogen fluoride is 1 (26.4-36.0). Further, after the reaction is finished, the temperature of the reaction system is reduced to-10-20 ℃, and nitrogen is adopted for replacement, so that hexafluorophosphoric acid is obtained. Further, condensing the mixture obtained by replacement, and collecting a product at a temperature of-20-5 ℃ to obtain the recovered hydrogen fluoride. According to the preparation method of the hexafluorophosphoric acid, the oxygen-containing phosphorus compound and the anhydrous hydrogen fluoride are mixed and reacted at the temperature of 65-100 ℃ under the pressure of not lower than 0.4Mpa, so that the viscosity of the oxygen-containing phosphorus compound is reduced, the oxygen-containing phosphorus compound and the anhydrous hydrogen fluoride are fully contacted, the mass transfer effect is improved, and the yield of the hexafluorophosphoric acid is further improved. Detailed Description For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. At present, in order to prevent the decomposition of hexafluorophosphoric acid at high temperature, phosphorus pentafluoride and phosphorus oxytrifluoride (formula 1 and formula 2) are produced, and it is common to control the reaction rate by lowering the temperature during the reaction to thereby inhibit the decomposition of hexafluorophosphoric acid. However, the raw material oxygen-containing phosphorus compound for preparing hexafluorophosphoric acid is mostly viscous liquid at low temperature, and the mass transfer effect of the reaction is poor, so that the yield of hexafluorophosphoric acid is low. In addition, the reaction process is exothermic, and if the low temperature condition is kept, the operation of cooling is needed, so that a large amount of energy consumption is generated. Therefore, simple control of the reaction temperature cannot achieve high yields. Formula 1; Formula 2. In view of this, the present invention provides a method for preparing hexafluorophosphoric acid, comprising the steps of: Mixing an oxygen-containing phosphorus compound with anhydrous hydrogen fluoride, and rea