Technique for preparing phosphorus pentafluoride

Abstract

The invention discloses a preparation process of phosphorus pentafluoride, which has the reaction formula of 5F2 +2P -2PF5, and has the following process steps: solid single substance phosphate is pre-added in a gas solid reaction device, the internal pressure of the gas solid reaction device is controlled to be less than 0.5 MPa, fluorine gas is introduced under the condition that the reaction temperature is lower than 600 DEG C, then the crude product of the phosphorus pentafluoride is produced, and the crude product is cooled between minus 35 DEG C and minus 60 DEG C through a pre-cooler, and then introduced into a rectifying tower, the temperature of a reboiler in the rectifying tower is controlled between minus 35 DEG C and minus 40 DEG C, the temperature of a condenser in the rectifying tower is controlled between minus 60 DEG C and minus 85 DEG C, the whole reflux is kept, the reflux ratio is controlled to be 10:1 to 1:1 after the balance is reached, and the finished product of the phosphorus pentafluoride is obtained by the rectification separation The preparation process of the phosphorus pentafluoride has the advantages of simple process work and equipment structure, high reliability, simple reaction process, single product and high product purity.

Description

technical field [0001] The invention relates to a preparation process of phosphorus pentafluoride. Background technique [0002] Phosphorus pentafluoride is a colorless gas with a melting point and boiling point of -94°C and -84°C under normal pressure, respectively. As a catalytic fluorinating agent, etc. [0003] In recent years, with the increasing popularity and promotion of high-performance mobile electronic products, the requirements for high-performance secondary batteries are getting higher and higher. Lithium-ion secondary batteries with lithium hexafluorophosphate as electrolyte have been widely used because of their many advantages. Phosphate gas has been used as a raw material for the synthesis of lithium hexafluorophosphate. However, the manufacture of lithium hexafluorophosphate puts forward higher requirements on the purity of phosphorus pentafluoride, so the synthesis of high-purity phosphorus pentafluoride is undoubtedly of great significance for the synth...

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Problems solved by technology

[0017] In the method described above, using PCl 5 +HF→PF 5 The synthesis of phosphorus pentafluoride gas based on the principle of +5HCl has been applied in the synthesis process of lithium hexafluorophosphate. However, due to the use of PCl 5 , PCl 5 It often contains a certain amount of water, phosphoric acid, etc., plus synthetic PF 5 Corrosive HCl is generated during the process, which greatly enhances the corrosion of the equipment and puts forward higher requirements for the reliability of the equipment

Due to the complexity of the reaction process in other preparation processes, the product often contains a large amount of impurities, making it difficult to obtain a high-purity target product

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