Preparation method of 2, 3, 3, 3-tetrafluoropropene

Abstract

The invention provides a preparation method of 2, 3, 3, 3-tetrafluoropropene, which comprises the following steps: taking monochlorodifluoromethane (R22) and methane chloride (methyl chloride) as raw materials and carrying out thermal cracking reaction at a high temperature of 600-1000 DEG C under the condition that N2 exits to prepare the 2, 3, 3, 3-tetrafluoropropene, wherein the volume ratio of the monochlorodifluoromethane to the methane chloride is 1-3:1, and the retention time of a reactant is 0.01-0.2 seconds. The reaction raw material used in the preparation method is easy to obtain, the defect of high cost of the used raw material in the prior art is overcome, the production cost is greatly reduced, and the reaction process is simple. The prepared 2, 3, 3, 3-tetrafluoropropene has the advantages of zero ODP and low GWP and can be used as a substitute of an automotive air-conditioning refrigerant.

Description

technical field [0001] The present invention relates to a preparation method of fluorinated olefin, which is a novel refrigerant with excellent performance, specifically a preparation method of 2,3,3,3-tetrafluoropropene (HFO-1234yf), which has a relatively low Greenhouse potential (low GWP), zero ozone depletion potential (zero ODP) and cause people's widespread concern, the invention belongs to chemical technical field. Background technique [0002] In recent years, the problem of global warming has become increasingly serious, and reducing greenhouse gas emissions has become one of the focuses of global environmental protection. The "Montreal Protocol" has determined the phase-out schedule of HCFCs. At present, the substitutes of HCFCs are mainly HFCs and their mixtures, including R-32, R-134a, R-152a and so on. Although the ozone depletion potential (ODP) of HFCs is 0, it has a high greenhouse effect potential (GWP), and has been included in the annex of greenhouse gase...

AI Technical Summary

Problems solved by technology

The reaction raw materials used in this reaction are relatively expensive and difficult to obtain, thereby increasing the cost. In addition, since the removal of HF requires organic solvents such as ether and aryl nitrile, the environmental pollution is serious, so the development of industrialization is hindered.

In the 1980s, Daikin Corporation also began to study the preparation of HFO-1234yf. At that time, HFO-1234yf was mainly used as a polymerized monomer and comonomer. The Daikin publication number was US73038947, and the basic method introduced was to use fluoroethanol as a raw material (general formula is R f CF 2 CH 2 ZOH) and thionyl chloride are prepared by reacting in N,N-dimethylformamide solution under the action of amino compound as a catalyst to obtain R f CF 2 CH 2 Cl, then the resulting product R f CF 2 CH 2 Cl reacts with metal zinc to obtain the target product. Since the toxic organic solvent thionyl chloride is used in the reaction process, it is difficult to handle the organic solvent used after the reaction. In addition, the second step reaction yield in this patent is very low. Comprehensive consideration of this method is difficult to achieve industrialization

Domestic research on the preparation of HFO-1234yf is less, and there are almost no reports on the industrialization technology of HFO-1234yf