Preparation method of Z-1,1,1,4,4,4-hexafluoro-2-butene

Abstract

The invention relates to a preparation method of Z-1,1,1,4,4,4-hexafluoro-2-butene, belonging to the field of chemical synthesis. The method comprises the following steps of taking hexachlorobutadiene (HCBD) as a raw material, performing gas-phase catalytic chlorination-fluoridation separation to obtain 2,3-dichlorohexafluoro-2-butene, performing liquid-phase dechlorination to obtain hexafluoro-2-butyne, and preparing the Z-1,1,1,4,4,4-hexafluoro-2-butene (Z-HFO-1336mzz) by means of performing gas-phase catalytic hydrogenation, wherein three reactions are included totally. The Z-1,1,1,4,4,4-hexafluoro-2-butene with high selectivity is obtained by means of performing catalytic hydrogenation by adopting the hexafluoro-2-butyne, and meanwhile the product is easily separated from side products and the raw material. The method disclosed by the invention has the advantages that the original raw material is easily obtained, the activity of a catalyst is high, the service life of the catalyst is long, the raw material can be recycled, and the standard of zero emissions is reached.

Description

technical field [0001] The present invention relates to a preparation method of Z-1,1,1,4,4,4-hexafluoro-2-butene (Z-HFO-1336mzz), in particular to a method starting with hexachlorobutadiene Raw materials, chlorofluorination reaction in the presence of fluorination catalyst first, then dechlorination reaction in the presence of zinc powder, and finally hydrogenation in the presence of hydrogenation catalyst to obtain Z-1,1,1,4,4,4-hexa Process for the preparation of fluoro-2-butene. Background technique [0002] Z-1,1,1,4,4,4-hexafluoro-2-butene (Z-HFO-1336mzz), with low greenhouse effect potential (GWP) and zero ozone depletion potential (ODP), It is considered to be an ideal substitute with the most potential to replace 1,1-dichloro-1-fluoroethane (HCFC-141b), and can be used as a refrigerant, blowing agent, fire extinguishing agent, etc. [0003] U.S. Patent US5463150 reported that in sulfolane solvent, 190 ° C, 1,2-dichloro-1,1,4,4,4-pentafluorobutane or 2-chloro-1,1,1...

AI Technical Summary

Problems solved by technology

There are following defects in these routes: firstly, various literatures do not list the single-pass yield data of Z-1,1,1,4,4,4-hexafluoro-2-butene, and the yields given are generally The sum of the yields of Z-1,1,1,4,4,4-hexafluoro-2-butene and E-1,1,1,4,4,4-hexafluoro-2-butene, generally The yield of Z-1,1,1,4,4,4-hexafluoro-2-butene in the method is very low, while E-1,1,1,4,4,4-hexafluoro-2-butene Alkenes are very high; secondly, 1,2-dichloro-1,1,4,4,4-pentafluorobutane, 2-chloro-1,1,1,4,4,4-hexafluorobutane Or 1,1,1-trifluoro-2-bromo-2-chloroethane is the defect that the raw material price is expensive and difficult to obtain in the route of starting raw material; With 1,1-dichloro-3,3,3-three The coupling route with fluoroethane as the starting material produces a large amount of waste liquid that is difficult to recycle, and the resulting pollution is very serious; the route of hexafluoropropylene as the starting material is relatively long, and hexafluoropropylene is difficult to transport, and there is detonation. The danger of hexachlorobutadiene is that the route of starting raw material is corroded seriously, pollutes serious problem, and wherein the liquid phase system that antimony pentachloride or titanium tetrachloride and HF forms is very strong to the corrosion of equipment, and Pollution is also very serious

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