Preparation method of trifluoroethylene

Abstract

The invention discloses a preparation method of trifluoroethylene, which comprises the following steps: mixing 1,1,1,2-tetrafluoroethane with octafluorocyclobutane according to the molar ratio of 1:1-9 under the action of a cracking catalyst for reaction, controlling the reaction temperature to be 350-550 DEG C, the reaction airspeed to be 500-2000 hours-1 and the reaction pressure to be normal pressure and obtaining the trifluoroethylene after cracking gas generated by reaction is quenched, washed, alkali-cleaned, dried, compressed, rectified and purified. The preparation method has the advantages of low reaction temperature, simplicity in separation and purification and low cost, the maximum conversion rate of the 1,1,1,2-tetrafluoroethane is 56.3 percent, and the maximum selectivity of the trifluoroethylene is 97.5 percent.

Description

technical field [0001] The invention relates to a method for preparing trifluoroethylene, in particular to a method for preparing trifluoroethylene from 1,1,1,2-tetrafluoroethane and octafluorocyclobutane. Background technique [0002] Trifluoroethylene is an important fluorine-containing intermediate. Polycondensation of trifluoroethylene and ethanol can produce environmentally friendly cleaning agent hydrofluoroether; addition of trifluoroethylene and bromine, and then dehydrobromination can obtain trifluorobromide Ethylene is the raw material for the manufacture of fluorinated bromine oil. Trifluoroethylene is also an important polymer monomer. The fluorine-containing resin synthesized with it has unique electrical properties and has wide application value in electronics, military, medical and other industries. Trifluoroethylene can also be used as an intermediate in the synthesis of biologically active components. Trifluoroethylene is highly flammable, easy to self-poly...

AI Technical Summary

Problems solved by technology

Trifluoroethylene is highly flammable, easy to self-polymerize, and will form an explosive gas mixture with air, making it difficult to transport and store for a long time

[0004] Patents such as US5053377 and JP2178238 disclose the preparation of trifluoroethylene by catalytic dechlorination and hydrogenolysis of 1,1,2-trifluoro-2,2,1-trichloroethane under the presence of metal composite catalysts such as Pd and Au. The route is mainly used to produce chlorotrifluoroethylene, the selectivity of trifluoroethylene is poor, separation and purification are difficult, and it is difficult to obtain high-quality trifluoroethylene

[0005] Patents such as JP62252736 and US5089454 disclose the preparation of trifluoroethylene by catalytic hydrogenolysis of chlorotrifluoroethylene under Pd or Pt-containing catalysts supported by magnesium oxide or activated carbon. This route requires the construction of special synthesis and separation devices. And equipment investment is huge, production cost is high

[0006] In addition, foreign patents such as US5856593A, FR2710054, and FR2729136 disclose methods for preparing trifluoroethylene from the route of 1,1,1,2-tetrafluoroethane, mainly using AlF 3 Lewis acid catalyst, nitrogen as a diluent, the reaction requires a higher temperature, at 600 ° C, the conversion rate of 1,1,1,2-tetrafluoroethane is only 34%, and the catalyst activity is not high, and the product is separated and difficult to purify

[0007] Chinese patents such as CN102372593A, CN101851146A disclose the method for preparing trifluoroethylene by liquid-phase debromination of fluorobromoalkane with zinc dehalogenating agent, the route trifluoroethylene yield is low, the cost of raw materials is high, and the amount of three wastes is large

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