A kind of method utilizing cyclic reaction to prepare hexafluoroethane

Abstract

The invention relates to a method for preparing hexafluoroethane by cyclic reaction, which belongs to the technical field of fluorine chemical industry. The method steps: fluorine gas or a mixed gas of nitrogen gas and fluorine gas, and tetrafluoroethylene enter a reactor with a temperature of 10-60° C. and a pressure of 0.1-0.15 MPa from different feed ports, and control the gas flow in the reactor The space velocity is 0.2-10 / min, and the reaction is carried out. The obtained part of the reaction product is circulated at the outlet of the reactor through the centrifugal fan of the external circulation equipment of the reactor and returned to the inlet of the reactor, and the fluorine or nitrogen gas and The mixed gas of fluorine gas and tetrafluoroethylene enters the reactor after being mixed, and the reaction is circulated; another part of the obtained reaction product comes out directly from the discharge port to obtain the hexafluoroethane. The method of the invention has the advantages of simple process, mild reaction conditions and cheap reactor price; the prepared hexafluoroethane has high concentration, low impurity content and high yield.

Description

technical field [0001] The invention relates to a method for preparing hexafluoroethane by cyclic reaction, which belongs to the technical field of fluorine chemical industry. Background technique [0002] Hexafluoroethane is an important chemical product, mainly used in integrated circuit etching and cleaning, refrigeration, high dielectric strength cooling, etc. At present, the methods for preparing hexafluoroethane are as follows: [0003] (1) In the patent CN00118734.1, cobalt difluoride is contacted with fluorine gas to be activated into cobalt trifluoride, and hydrofluoroethane is converted into perfluoroethane through the activated cobalt trifluoride catalyst at 300-350°C ; [0004] (2) In the patent CN1165803A, under high temperature, fluorine gas reacts with a hydrofluorocarbon with two carbon atoms in the presence of a diluent; [0005] (3) In patent CN1651370, in the presence of a fluorination catalyst, the mixed gas of hexafluoroethane and chlorotrifluorometha...

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Problems solved by technology

[0009] In the above methods, there are different problems, such as low yield, harsh process conditions, expensive reactor, high risk of operation, high corrosiveness of raw materials, slow reaction speed, low product concentration, etc.

As in method (5), there is a large amount of low-temperature tetrafluoroethylene in the reactor, and tetrafluoroethylene is very unstable, prone to detonation reaction, and the risk is high; in method (6), chlorofluoroalkane diluent and hexafluoroethane It is an azeotrope, which is difficult to separate by rectification

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