124 results about "Phosphorus pentafluoride" patented technology

The invention belongs to the technical field of electrolyte, and particularly relates to a method for preparing liquid lithium hexafluorophosphate from sodium hexafluorophosphate. The method comprises the following steps: adding a sodium source into a hexafluorophosphoric acid aqueous solution for neutralization reaction to obtain a sodium hexafluorophosphate aqueous solution, then extracting to remove water, drying to obtain a sodium hexafluorophosphate solid, and heating and decomposing the sodium hexafluorophosphate solid to obtain phosphorus pentafluoride gas; the phosphorus pentafluoride gas is not mixed with SO3, POF3, HF and other impurity gases, a complex refining and purifying process is not needed, and the phosphorus pentafluoride gas with the purity exceeding 99.9% can be obtained after simple purification and can be directly used for synthesizing liquid lithium hexafluorophosphate. The method does not generate waste acid, does not need a complicated phosphorus pentafluoride gas purification process, is particularly suitable for the requirements of the lithium battery industry on high-purity electrolyte, and has the remarkable advantages of high product purity, small environmental pollution, low production cost and the like.

A synthesis method for phosphorus pentafluoride and a synthesis device therefor. The synthesis method comprises: continuously feeding hydrogen fluoride, liquid chlorine and liquid yellow phosphorus into a reactive distillation tower to perform a reaction, so as to obtain phosphorus pentafluoride gas, wherein the molar ratio of hydrogen fluoride, liquid chlorine and liquid yellow phosphorus is 8-12:4-6:1-3. By using hydrogen fluoride, liquid chlorine and liquid yellow phosphorus as raw materials, liquid yellow phosphorus reacts with liquid chlorine in advance in a reactive distillation tower and the resulting product then reacts with hydrogen fluoride, thereby synthesizing phosphorus pentafluoride gas by means of a one-step method. The preparation process is simple, and the synthesis device has a stable and reliable structure and is very suitable for large-scale production, implementation and use.

The present invention provides a synthesis system and a synthesis method for lithium hexafluorophosphate. The synthesis system comprises a gas-liquid reaction kettle and a built-in microbubble generation unit provided in the gas-liquid reaction kettle; a material inlet and a gas inlet are formed in the side wall of the gas-liquid reaction kettle; the built-in microbubble generation unit comprises a first microbubble generator and a second microbubble generator, the first microbubble generator is provided below the liquid level in the gas-liquid reaction kettle and connected to the material inlet, and the second microbubble generator is provided at the bottom end of the gas-liquid reaction kettle and connected to the gas inlet; a plurality of layers of perforated plates are successively provided in the gas-liquid reaction kettle from top to bottom; through holes of said perforated plates are staggered, and said perforated plates are provided between the first microbubble generator and the second microbubble generator. The synthesis system of the present invention increases the area of mass transfer between lithium fluoride liquid and phosphorus pentafluoride gas, increases the reaction rate, and reduces energy consumption.

The invention relates to a preparation method of a lithium difluoro bis (oxalate) phosphate concentrated solution, and belongs to the technical field of lithium battery electrolyte additives. Adding lithium oxalate into a solvent, stirring and dissolving to obtain a lithium oxalate solution; the method comprises the following steps: adding a modified fluorine ion chelating agent into a lithium oxalate solution, stirring, filtering, putting into a reactor, and slowly introducing phosphorus pentafluoride gas; after the introduction is finished, heating and stirring for reaction; after the reaction is finished, filtering reaction liquid to remove unreacted solid impurities, so as to obtain a lithium difluoro bis (oxalate) phosphate concentrated solution; the modified fluorine ion chelating agent is prepared from D301 ion exchange resin, dichloroethane, propylene-1-base boronic acid pinacol ester, mercaptoethyl guanidine dihydro bromide and sodium tert-butoxide. The lithium difluoro bis (oxalate) phosphate prepared by the method is high in purity and high in yield, and meets the use requirements of lithium ion battery electrolyte on lithium salt.

The invention belongs to the technical field of electrochemical energy storage, and particularly relates to a battery capable of supplementing lithium or sodium in situ, which comprises a positive plate, a negative plate and an electrolyte, and is characterized in that the electrolyte contains a component A, and a positive electrode and / or a negative electrode contains a component B; the structural general formula of the component A is X-Y, and X is lithium fluorosulfonate, sodium fluorosulfonate, lithium difluorophosphate or sodium difluorophosphate; y is boron trifluoride or phosphorus pentafluoride; the component B is at least one of lithium oxalate, sodium oxalate, lithium fluoride and sodium fluoride. Compared with the prior art, the component A and the component B are simultaneously added into the battery disclosed by the invention, so that the battery shows more excellent cycle performance and high-temperature performance. The combination mode has better performance compared with the mode that the component B is independently used in the electrode material or the component A is independently used in the electrolyte.

The invention relates to a preparation method of phosphorus pentafluoride, which comprises the following steps: mixing a fluorocarbon compound with a phosphorus oxide compound and an oxidizing agent, reacting in a dry closed environment at high temperature and high pressure, collecting gas, and purifying to obtain the phosphorus pentafluoride. The invention also discloses a preparation method of lithium hexafluorophosphate, which comprises the following step: carrying out gas-solid reaction on the obtained phosphorus pentafluoride and lithium fluoride in a fluidized bed to prepare the lithium hexafluorophosphate. The method solves the problems of low purity of lithium hexafluorophosphate, difficulty in treatment of byproducts, low production efficiency and the like in the prior art.

The utility model relates to a lithium hexafluorophosphate synthesis reaction kettle. The lithium hexafluorophosphate synthesis reaction kettle comprises a kettle body, a reaction liquid inlet pipe is arranged on the kettle body, a gas outlet pipe is arranged on the kettle body, a deep freezer is arranged on the gas outlet pipe, a gas distributor is arranged on the lower side in the kettle body, a reaction gas inlet pipe communicated with the gas distributor is arranged on the kettle body, and a gas outlet pipe communicated with the gas distributor is arranged on the reaction gas inlet pipe. An upper stirring shaft and a lower stirring shaft are rotatably mounted in the kettle body, the lower stirring shaft and the upper stirring shaft are coaxially arranged, a transmission mechanism for realizing reverse rotation of the upper stirring shaft and the lower stirring shaft is arranged in the kettle body, and a driving mechanism for driving the upper stirring shaft to rotate is arranged on the kettle body. Phosphorus pentafluoride gas can enter the kettle body more dispersedly through the gas distributor, so that the dispersity of reaction gas in reaction liquid is improved, and the reaction rate and the utilization rate of the reaction liquid are improved. The upper stirring shaft and the lower stirring shaft which rotate in opposite directions simultaneously stir the reaction liquid in the kettle body, so that the mixing effect of the reaction liquid and the reaction gas is enhanced, and the reaction rate is increased. And the reacted liquid is discharged through a discharge pipe at the bottom, and the gas is discharged after part of phosphorus pentafluoride flows back through a deep freezer.

The present invention belongs to the technical field of phosphorus pentafluoride preparation, and specifically relates to a method for synthesizing phosphorus pentafluoride by using yellow phosphorus and fluorine gas. The synthesis method comprises the steps of dissolving yellow phosphorus in an inert solvent to prepare a yellow phosphorus solution, then passing the yellow phosphorus solution and fluorine gas into a microchannel reactor for mixed reaction, and separating and purifying the generated gaseous product through a pressurized condensation system to obtain phosphorus pentafluoride. The synthesis method of the present invention utilizes a specific inert solvent to dissolve highly reactive yellow phosphorus, and then continuously synthesizes phosphorus pentafluoride by reacting the yellow phosphorus solution with fluorine gas in a microchannel reactor through a gas-liquid phase reaction. The method has the advantages of low reaction temperature, high reaction efficiency, few reaction by-products, and high product yield.

A method for producing phosphorus trifluoride and a method for producing phosphorus pentafluoride, which have high reaction efficiency, low reaction temperature and an excellent energy efficiency. The method includes: a step of introducing phosphorus trichloride and hydrogen fluoride into a first reactor, and a step of discharging phosphorus trifluoride from the first reactor, the first reactor contains carbon material. The method includes a step of introducing the phosphorus trifluoride obtained above and chlorine into a second reactor, and a step of discharging dichloro-phosphorus trifluoride from the second reactor. The method further includes a step of introducing the dichloro-phosphorus trifluoride obtained above and hydrogen fluoride into a third reactor; and a step of discharging phosphorus pentafluoride from the third reactor. The method further includes a step of introducing the phosphorus pentafluoride obtained above and lithium fluoride into a fourth reactor; and a step of discharging lithium hexafluorophosphate from the fourth reactor.

The present invention provides an automatic control method for a continuous automatic production device of phosphorus pentafluoride, comprising the following steps: S10, opening the first pipeline to fill the cartridge with an inert gas, and opening the first air outlet to discharge the residual air and water vapor in the cartridge; S11, after closing the first pipeline and the first air outlet, feeding through the feed inlet, and closing the feed inlet after the feeding is completed; S12, opening the second pipeline to fill each weighing and conveying bin with an inert gas, and opening the exhaust port to discharge the residual air and water vapor in the weighing and conveying bin, and closing the second pipeline and the exhaust port; S13, opening the feed valve and the weighing and conveying unit to weigh phosphorus pentachloride and then feed it, and simultaneously opening the hydrogen fluoride supply tank to feed anhydrous HF, wherein the phosphorus pentachloride and the fluoride are fed in proportion.

The present invention provides a preparation method for co-producing lithium difluorophosphate and lithium hexafluorophosphate, which comprises the following steps: 1) Dissolve lithium phosphate in a carbonate solvent to obtain a lithium phosphate solution, and adjust the temperature of the solution to 5-10 °C; 2) Introduce phosphorus pentafluoride gas into the aforementioned lithium phosphate solution and gradually carry out a reaction to generate lithium difluorophosphate and lithium fluoride. The lithium fluoride continues to react with phosphorus pentafluoride to generate lithium hexafluorophosphate. Finally, the molar ratio of lithium phosphate to phosphorus pentafluoride is 1:2 ± 0.1, and a solution of lithium difluorophosphate and lithium hexafluorophosphate is obtained. Among them, lithium hexafluorophosphate dissolves in the carbonate solution to form a lithium hexafluorophosphate solution, and lithium difluorophosphate is slightly soluble in the carbonate and precipitates in the form of crystals to form a turbid solution; 3) Separate the lithium hexafluorophosphate solution and the lithium difluorophosphate turbid solution. The crystalline lithium difluorophosphate is dried to obtain the finished product, and the concentration of the liquid-phase lithium hexafluorophosphate can be directly adjusted and then enter the electrolyte system.

This invention belongs to the field of lithium-ion battery electrolyte material preparation technology, and provides a solid lithium hexafluorophosphate with low fine crystal content and its preparation method. The preparation method involves adding lithium fluoride to anhydrous hydrogen fluoride to form anhydrous hydrogen fluoride slurry. A portion of the anhydrous hydrogen fluoride slurry and phosphorus pentafluoride gas are fed into a primary continuous reaction crystallizer. The resulting slurry is subjected to low-temperature fractionation to form a first stream and a second stream. The second stream enters a secondary continuous growth crystallizer and continues to react with phosphorus pentafluoride gas, followed by solid-liquid separation to obtain a solid wet product and mother liquor. The first stream, another portion of the anhydrous hydrogen fluoride slurry, and a portion of the mother liquor enter a pre-conditioning section, and the resulting pre-conditioned stream is returned to the feed end of the primary continuous reaction crystallizer. The solid wet product is then subjected to low-temperature washing and programmed vacuum drying to obtain the final product. This method, through the combination of fractional reflux, mother liquor participation in pre-conditioning, and continuous growth processes, reduces fine crystal entrainment and improves particle size distribution stability.

The present invention belongs to the technical field of phosphorus pentafluoride preparation, and in particular to a method for efficiently synthesizing phosphorus pentafluoride using phosphoric acid and hydrogen fluoride. The synthesis method comprises the following steps: adding phosphoric acid and anhydrous hydrogen fluoride into a reactor at a temperature of 20°C to 10°C and mixing them uniformly, then passing SF4 into a mixed reaction, introducing the reaction mixture into a thermal decomposition kettle for thermal decomposition, and performing rectification and separation on the gas phase product obtained by decomposition to obtain high-purity phosphorus pentafluoride; wherein the molar ratio of the phosphoric acid and anhydrous hydrogen fluoride added is 1:1~2; the molar ratio of the SF4 to phosphoric acid is 2~2.5:1. The present invention uses phosphoric acid and anhydrous hydrogen fluoride as raw materials, and by adding SF4 as a dehydrating agent and an auxiliary fluorinating agent, the efficiency of the fluorination reaction can be significantly improved, and the product quality and yield can be improved. The synthesis method of the present invention has the advantages of mild conditions, simple process, low equipment requirements, and environmental protection and high efficiency.

The utility model discloses a phosphorus pentafluoride generating system for a lithium hexafluorophosphate generator. The phosphorus pentafluoride generating system comprises a phosphorus pentafluoride generator, a phosphorus pentachloride feeding valve, a phosphorus pentafluoride reaction valve, a phosphorus pentafluoride feeding valve and a feeding emptying valve, one end of the phosphorus pentachloride feeding valve is connected to a phosphorus pentachloride positive pressure sending tank through a pipeline, the other end of the phosphorus pentachloride feeding valve is connected to one end of the phosphorus pentafluoride reaction valve through a pipeline, and the other end of the phosphorus pentafluoride reaction valve is connected to a feeding port of the phosphorus pentafluoride generator; a discharge port of the phosphorus pentafluoride generator is respectively connected to one end of the phosphorus pentafluoride feeding valve and one end of the feeding emptying valve through pipelines, the other end of the phosphorus pentafluoride feeding valve is connected to the lithium hexafluorophosphate generator through a gas filter, and the other end of the feeding emptying valve is connected to a tail gas collecting device through a pipeline. According to the utility model, the feeding misoperation can be eliminated, the feeding safety is ensured, and the feeding can be controlled to be correct.

The invention relates to the technical field of synthesis of hexafluorophosphate, in particular to a synthesis method and a synthesis system of liquid hexafluorophosphate. The synthesis method of the liquid hexafluorophosphate is a new process route, phosphorus trichloride is used as an initial raw material, and a reaction is carried out with a reaction kettle; phosphorus pentafluoride sequentially subjected to oxidation, fluorination, deep fluorination and solvent in-situ capture reacts with alkali metal fluoride to obtain liquid hexafluorophosphate; the whole technical route process has the advantages of controllability, low cost, greenness, high safety and few impurities.

The invention provides a method for purifying hydrogen chloride in fluorine-containing hydrogen chloride tail gas. The method comprises the following steps: enabling tail gas containing trace phosphorus pentafluoride, hydrogen fluoride and hydrogen chloride to pass through an adsorption column, and carrying out in-situ reaction on water generated after the hydrogen fluoride is chemically adsorbed by an adsorption column filling material and phosphorus pentafluoride to generate phosphorus oxyfluoride; gas at an outlet of the adsorption column passes through a microporous gas distributor, the gas reacts with a metal organic reagent, and then high-purity hydrogen chloride gas is obtained after hydrogen fluoride is separated through rectification. According to the method, high-purity hydrogen chloride can be prepared, and emission of pollutant-containing gas is reduced.

The invention discloses a waste new energy battery crushing and sorting method. The method comprises the following steps that S1, a waste battery and a lithium hydroxide catalytic infiltration material are subjected to vacuum low-temperature freezing and disassembling; s2, neutralizing the lithium-containing precipitate by using an acidic solution to generate anhydrous lithium salt, absorbing the waste gas by using hydrogen fluoride, and synthesizing a precursor by using phosphorus pentafluoride; s3, performing vacuum fractional distillation, and separating low / high boiling point components by a three-way valve; s4, gradient freezing crystallization is conducted, crystals and mother liquor are centrifugally separated at the temperature of-20 DEG C to-50 DEG C at the speed of 1 DEG C / min to 5 DEG C / min, and S5, performing low-temperature vacuum drying on the crystal, and removing moisture and the organic solvent to obtain high-purity lithium hexafluorophosphate; s3, separating a low-boiling-point organic solvent and a high-boiling-point component by utilizing a temperature gradient in a vacuum environment, and preliminarily enriching a target product; in the S4 stage, the crystal precipitation rate is controlled through gradient cooling, so that lithium hexafluorophosphate preferentially forms high-purity crystals, efficient separation of the crystals and mother liquor is achieved in combination with a centrifugal separation technology, and the product purity is guaranteed through the synergistic effect of fractional distillation and gradient freezing.

An integrated process for co-production of phosphorus pentafluoride (PF5) and fluorosulfonic acid (HSO3F) in high yield and purity through a single reaction step is provided. The method comprises reacting a first reagent comprising an aqueous solution of hexafluorophosphoric acid (HPF6) and hydrofluoric acid (HF) with a second reagent comprising fuming sulfuric acid (H2SO4SO3), and recovering a product mixture comprising phosphorus pentafluoride (PF5) and fluorosulfonic acid (HSO3F).

The invention discloses a preparation method of phosphorus pentafluoride, which comprises the following steps: 1) mixing fluorine-containing inorganic salt and hydrogen-containing inorganic salt, and carrying out activation process treatment; and 2) adding phosphorus pentoxide into the system in the step 1) for reaction to generate phosphorus pentafluoride gas. The method has the advantages of low reaction temperature and high product purity, does not need to use high-toxicity and high-corrosivity hydrogen fluoride, and is environment-friendly, simple in process and suitable for industrial production.

The invention discloses a method for separating phosphorus pentafluoride-hydrogen chloride mixed gas, which comprises the following steps of: introducing the phosphorus pentafluoride-hydrogen chloride mixed gas into a reaction kettle by taking a perfluoropolypropyl ether fluorinated solution as a solvent and lithium fluoride as a raw material, so that the phosphorus pentafluoride and the lithium fluoride react to generate lithium hexafluorophosphate, and hydrogen chloride is discharged in a gas phase manner; heating the generated lithium hexafluorophosphate to decompose the lithium hexafluorophosphate into phosphorus pentafluoride and lithium fluoride, discharging the phosphorus pentafluoride in a gas phase manner, and retaining the lithium fluoride in the perfluoropolypropyl ether fluorinated solution for recycling; the solvent and raw materials provided by the invention can be recycled for multiple times, the whole process flow is greatly simplified, and efficient and stable separation of HCl and phosphorus pentafluoride is realized.

The invention belongs to the technical field of lithium ion battery electrolyte, and particularly relates to a method for jointly preparing bis (fluorosulfonyl) imide and monofluorophosphate. The preparation method comprises the following steps: reacting urea, chlorosulfonic acid and phosphorus pentafluoride serving as raw materials to generate a mixture of bis (fluorosulfonyl) imide acid and monofluorophosphoric acid, distilling to remove HCl and PF5 impurities in the mixture, and reacting the mixture with alkali metal salt under the poor solvent condition of monofluorophosphate to obtain a solid-liquid mixture; and carrying out solid-liquid separation on the solid-liquid mixture, and drying the obtained solid to obtain monofluorophosphate, and concentrating the obtained filtrate, adding a poor solvent for recrystallization, filtering and drying to obtain the bis (fluorosulfonyl) imide salt. According to the method, two acids can be synthesized through one-step reaction, the synthesis process flow is simple, the reaction time is short, the production efficiency can be remarkably improved, and the production cost is saved. And the prepared monofluorophosphate and bis (fluorosulfonyl) imide salt are high in quality and can be widely applied to lithium ion battery electrolyte.

The invention relates to a preparation process of high-purity lithium hexafluorophosphate, which comprises the following specific steps: S1, quantitatively adding anhydrous hydrogen fluoride into a corresponding reaction kettle body, and controlling the environment temperature in the reaction kettle body at-50 DEG C to-20 DEG C through a temperature control device; s2, maintaining the pressure in the reaction kettle body at 0.1-0.5 MPa, dispersing and adding solid phosphorus pentachloride into the reaction kettle body through a corresponding feeding device, and enabling the solid phosphorus pentachloride to react with the anhydrous hydrogen fluoride in the step S1 at the temperature of-50 DEG C to-20 DEG C to obtain phosphorus pentafluoride and gaseous hydrogen chloride, the gaseous hydrogen chloride escapes from the reaction liquid and then is discharged for recovery or absorption treatment; and S3, dispersing and adding lithium fluoride into the reaction kettle body through the feeding device, and carrying out complexing reaction on the lithium fluoride and phosphorus pentafluoride in the anhydrous hydrogen fluoride to obtain lithium hexafluorophosphate. The reaction process is high in controllability, so that the high-purity lithium hexafluorophosphate product can be stably prepared.

The invention relates to the technical field of secondary batteries, in particular to a combined preparation method of lithium difluorophosphate and lithium tetrafluoroborate. The combined preparation method of the lithium difluorophosphate and the lithium tetrafluoroborate comprises the following steps: reacting lithium phosphate with phosphorus pentafluoride and boron trifluoride in a supercritical carbon dioxide fluid, and separating to obtain the lithium tetrafluoroborate and the lithium difluorophosphate. Supercritical carbon dioxide is adopted as a reaction solvent, lithium phosphate reacts with BF3 and PF5 to generate lithium difluorophosphate and lithium tetrafluoroborate, the reaction equation is PF5 + Li3PO4 + BF3 = 2LiPO2F2 + LiBF4, the problem that the reaction solvent and reaction gas are prone to complexation is avoided, the activity of PF5 and BF3 is high, the reaction efficiency is high, and the product yield can be increased.

The invention belongs to the technical field of chemical synthesis, and relates to a lithium battery electrolyte raw material production technology, in particular to a preparation method of phosphorus pentafluoride. The method comprises the following steps: adding phosphorus trichloride, liquid chlorine and hydrogen fluoride into a reactor in proportion, and reacting to prepare hydrogen chloride and phosphorus pentafluoride; the molar ratio of phosphorus trichloride to liquid chlorine to hydrogen fluoride is preferably 1: 1: 5, and the reactor comprises a bottom reaction section, a middle filler section and a top condensation section. The working pressure of the reactor is 0.1-3.0 MpaG, the temperature of the reaction section is 0-40 DEG C, and the temperature of the condensation section is-20 to-60 DEG C. The mixed gas of phosphorus pentafluoride and hydrogen chloride can be prepared in one step and conveyed to the rear end to be refined and separated. The method has the advantages of simple process flow, easily available raw materials, low production cost and high efficiency.

The utility model relates to the technical field of lithium hexafluorophosphate reaction equipment, in particular to a lithium hexafluorophosphate concentration kettle, which comprises a kettle body, a reaction cavity, a feed port, a discharge port and a stirring device, a lifting pipe is formed at the feed port, and a driving structure for controlling the lifting movement of the lifting pipe is arranged at the top of the kettle body; when the driving structure drives the lifting pipe to lift, the stirring end of the stirring device can be synchronously controlled to move, and the lifting pipe is controlled to lift through the driving structure, so that phosphorus pentafluoride gas can be fed into a solution in the reaction cavity when the phosphorus pentafluoride gas is fed into the reaction cavity, and the reaction efficiency is ensured.

The present invention provides a phosphorus pentafluoride preparation method, which comprises: mixing a hexafluorophosphoric acid solution and a dehydrating agent, and carrying out a dehydration reaction at a temperature of 30-160 DEG C under a pressure of 0.1-3 MPa, wherein the hexafluorophosphoric acid solution contains water and hydrogen fluoride; after the dehydration reaction is finished, the reaction system is subjected to rapid pressure relief, and mixed gas containing phosphorus pentafluoride is obtained; wherein the pressure relief rate of the rapid pressure relief is greater than or equal to 0.1 MPa / min; and carrying out purification treatment on the mixed gas containing phosphorus pentafluoride to prepare the phosphorus pentafluoride gas.

Disclosed in the present application is a method for preparing lithium hexafluorophosphate. According to the embodiments of the present application, the method comprises: performing mixing treatment on phosphorus pentafluoride gas and a lithium fluoride solution to give a first treatment product; and performing reaction treatment on the first treatment product to give a reaction solution containing lithium hexafluorophosphate, wherein the mixing treatment is performed in a first continuous flow reactor, and the reaction treatment is performed in a second continuous flow reactor. The method of the present application overcomes the defects in existing batch production techniques and effectively avoids the ineffective operation time of the start and end stages in conventional production, thereby improving the production efficiency and output per unit time.

The invention discloses tris (trimethylsilyl) phosphate and a preparation method thereof, and belongs to the field of chemical synthesis. The invention relates to a preparation method of tris (trimethylsilyl) phosphate, in particular to a preparation method of tris (trimethylsilyl) phosphate, which comprises the following steps: hexamethyldisiloxane and phosphorus pentafluoride are subjected to heating reaction under a stirring condition to obtain tris (trimethylsilyl) phosphate, and the molar ratio of hexamethyldisiloxane to phosphorus pentafluoride is (5-10): 1. Phosphorus pentachloride is replaced with phosphorus pentafluoride, and due to the fact that fluorine atoms are small in radius and large in electronegativity, phosphorus is high in electropositivity and small in steric hindrance, phosphorus pentafluoride can react with hexamethyldisiloxane more easily, a catalyst is not needed, the cost of tris (trimethylsilyl) phosphate can be greatly reduced, and the yield of tris (trimethylsilyl) phosphate is high.

The invention discloses a method for removing phosphorus pentafluoride in lithium hexafluorophosphate synthesis tail gas, which is characterized by comprising the following steps of: absorbing phosphorus pentafluoride in the lithium hexafluorophosphate synthesis tail gas by using a fluorine-containing solvent; according to the method, the fluorine content in the byproduct hydrochloric acid in the lithium hexafluorophosphate industry can be effectively reduced, the bottleneck problem of downstream utilization of the byproduct hydrochloric acid in the industry is solved, and meanwhile, the utilization rate of the phosphorus pentafluoride gas is increased.

The present invention discloses a method for preparing phosphorus pentafluoride gas, comprising the following steps: (1) reacting a phosphorus-containing compound with hydrogen fluoride and an organic acid anhydride dehydrating agent to generate a hexafluorophosphoric acid solution; and (2) heating the hexafluorophosphoric acid solution to decompose it into gaseous hydrogen fluoride and phosphorus pentafluoride. The method has high water removal efficiency, simple process, and is easy to be continuously produced.