The preparation method of 2,3,3,3-tetrafluoropropene

Abstract

The invention provides a preparation method of 2, 3, 3, 3-tetrafloropropylene. The method comprises the following steps: with monochlorodifluoromethane and monochloro methane which are in a molar ratio of (0.5-4):1 as reaction raw materials, preheating the reaction raw materials, then mixing with superheated steam, wherein the volume ratio of the superheated steam to the reaction raw materials is (1-20):1, the temperature of the superheated steam is 900-1100 DEG C, the temperature in the reaction section is 600-1100 DEG C, and the stay time of reactants in the reaction section is 0.01-1s; and quenching, deacidifying, drying and rectifying and separating the product mixed flow to obtain 2, 3, 3, 3-tetrafloropropylene. The method provided by the invention overcomes the deficiency that a hollow tube is prone to carbonization in pyrolysis and side reactions are complex, the equipment maintenance rate is reduced, and meanwhile, the reaction period is prolonged, and the utilization ratio of the device is improved. The method provided by the invention has the characteristics of use of easily available raw materials, simple reaction process and the like. The obtained 2, 3, 3, 3-tetrafloropropylene has the advantages of zero ODP (Ozone Depletion Potential) and low GWP (Global Warming Potential), and is used as a substituent of automotive air conditionor refrigerant.

Description

technical field [0001] The invention relates to a method for preparing hydrofluoroolefins, in particular to a method for preparing 2,3,3,3-tetrafluoropropene (HFO-1234yf). technical background [0002] The "Montreal Protocol" has determined the phase-out schedule of HCFCs. With the phase-out of HCFCs, the third-generation fluorine-containing refrigerant HFCs, as a substitute for HCFCs, has attracted more and more attention. However, among many HFCs substitutes , although they all have ozone depletion potential (that is, ODP is zero) and have no detrimental effect on the ozone layer, many HFCs have high greenhouse effect potential, such as 1,1,1,2-tetrafluoroethane (HFC- 134a) has zero ODP, but its GWP is as high as 1300. As the greenhouse effect becomes more and more serious, people pay more attention to environmental issues. The European Union requires that the GWP value of all new vehicle refrigerants in its member states cannot exceed 150. In view of this, the Kyoto Proto...

AI Technical Summary

Problems solved by technology

Because the reaction temperature of this method is as high as above 900°C, there are many side reactions and serious carbon formation, so the reaction pipeline needs to be dredged regularly, the production cycle is short, the efficiency is low, and the yield of this method is only 13%. Therefore, it is difficult to produce industrially

Since entering the 21st century, DuPont and Honeywell have used HFC-245eb, HFC-215cb, HFC-225cb, HFC-235cb, HFC-245cb, etc. as raw materials to prepare HFC-1234yf (2,3,3,3- Tetrafluoropropene), its disadvantage is that the post-treatment separation mixture is more complicated