A purification method and purification device for octafluoropropane

Abstract

The invention relates to an octafluoropropane purifying method and a purifying apparatus thereof, which belong to the field of fine chemical engineering. The purifying method employs a cold trap for light-discharge and heavy-removal processing of an octafluoropropane crude product, the light components and heavy components impurity content are greatly reduced; an adsorbent is used for adsorption, H2O content is reduced, a part of a fluorocarbon compound is absorbed; a rectification technology is employed, the high-boiling point and low-boiling point impurity can be removed by controlling the rectification parameters, the H2O content is less than 1 ppm, the content of the organic fluorocarbon compound is less than 1 ppm, the total impurity content is less than 10 ppm, cold amount and heat consumed during the rectification process are reduced, economic performance is good, and the octafluoropropane with purity of greater than 99.999% can be obtained after being purified. The purifying apparatus mainly comprises the cold trap, an adsorption tower and a rectifying tower, and is adapted to usage of the purifying method.

Description

Technical field [0001] The invention relates to a purification method and a purification device for octafluoropropane, and belongs to the field of fine chemicals. Background technique [0002] High-purity octafluoropropane electronic gas, as a cleaning agent and etching agent for electronic devices, is used in semiconductor manufacturing and the electronics industry. As the etching accuracy of semiconductor devices becomes higher and higher, the purity requirements for octafluoropropane are also higher and higher. Generally speaking, the purity of high-purity octafluoropropane used in large-scale integrated circuits is greater than 99.999%. [0003] The main preparation method of octafluoropropane at this stage is mainly to prepare octafluoropropane by reacting hexafluoropropene or heptafluoropropane with fluorine gas. Due to the fluorination and / or high temperature reaction involved in the preparation process, a large amount of heat is released and carbon-carbon is generated. , ...

AI Technical Summary

Problems solved by technology

The first type is the method of rectification, but because there are many kinds of impurities in octafluoropropane, there are often impurities with boiling points close to or azeotropic with perfluoroalkanes, so it is difficult to purify by rectification

The second type is the method of adsorption. The commonly used adsorbents are molecular sieves, activated carbon and carbon molecular sieves, etc., but some impurities have very little adsorption capacity in the adsorbents and are difficult to remove by this method.

The third category is the catalytic conversion method, which decomposes or converts impurities with a boiling point close to the boiling point of perfluoroalkane through a catalyst into impurities with a large difference in boiling point and perfluoroalkane boiling point, but this method is often only for some specific impurities efficient

[0005] The purification methods of the octafluoropropane have limitations. In the prior art, it is difficult to obtain a product with a purity greater than 99.999% by a single method of rectification, adsorption, catalytic conversion and membrane separation. Octafluoropropane

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