Preparation method of high purity phosphorus pentafluoride

Abstract

The invention provides a preparation method of high purity phosphorus pentafluoride. The preparation method comprises the following steps: step one, taking polyphosphoric acid and waterless hydrogen fluoride as the primary raw materials to prepare a hexafluorophosphoric acid water solution; step two, reacting the hexafluorophosphoric acid water solution obtained in the step one with sulfur trioxide so as to obtain a mixture of hexafluorophosphoric acid and sulfuric acid; step three, directly heating the mixture of the hexafluorophosphoric acid and sulfuric acid obtained in the step two without separation, condensing the generated phosphorus pentafluoride steam so as to obtain a coarse product of phosphorus pentafluoride; step four, refining the obtained coarse product so as to obtain high purity phosphorus pentafluoride with a purity more than 99.5%. The product prepared by the provided preparation method has a high purity and low purity content, wherein the phosphorus pentafluoride content is not less than 99.95%, the waterless hydrogen fluoride content is not more than 50 ppm, the water content is not more than 10 ppm, the metal ion content is not more than 1 ppm, and the content of other purities is not more than 5 ppm.

Description

technical field [0001] The invention belongs to the field of chemistry, and in particular relates to a preparation method of high-purity phosphorus pentafluoride. Background technique [0002] Phosphorus pentafluoride (PF 5 ) is a colorless gas with a pungent odor at normal temperature and pressure, with a melting point of -93.8°C and a boiling point of -84.6°C. PF 5 When it meets water and alkali, it will be hydrolyzed immediately, and it will fume violently in humid air. It will not corrode glass in a dry state. It can form complexes with amines, ethers, nitrates, sulfoxides, etc. [0003] PF 5 Widely used in electronics industry, battery manufacturing, polymer materials and catalysts and other fields. In semiconductor manufacturing, PF 5 Doping by changing into plasma gas under the action of microwave can significantly improve the performance of semiconductors. In the field of polymers, PF 5 It can be used in the synthesis of fluorinated organic dithiophosphates, ...

AI Technical Summary

Problems solved by technology

However, the by-products of this method are very polluting to the environment and have been discontinued.

The above-mentioned other methods all have the disadvantages of high impurity content in the obtained product, difficulty in separation and purification, high requirements for equipment, and harsh process conditions, resulting in high production costs.