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

Abstract

The invention discloses a preparation method of E-1,1,1,4,4,4-hexafluoro-2-butene. The preparation method comprises the following step: in the presence of a catalyst, performing an isomerization reaction on Z-1,1,1,4,4,4-hexafluoro-2-butene to obtain the E-1,1,1,4,4,4-hexafluoro-2-butene, wherein the catalyst is activated carbon or metal fluoride. By the technical method provided by the invention,a raw material is easy to obtain, the conversion rate is high, and the reaction is easy to control; a reaction mixture is purified by distillation, a product is obtained on the tower top and can be further purified, and the raw material in a tower kettle can be recycled into a reactor, so that continuous mass production of the E-1,1,1,4,4,4-hexafluoro-2-butene is achieved.

Description

technical field [0001] The present invention relates to a gas phase preparation of E-1,1,1,4,4,4-hexafluoro-2-butene (E-HFO-1336mzz), in particular to a kind of Z-1,1,1,4 , 4,4-hexafluoro-2-butene (Z-HFO-1336mzz) as a raw material, in the presence of a catalyst isomerization reaction to obtain E-HFO-1336mzz method. Background technique [0002] Up to now, various documents have disclosed eight routes for the synthesis of E-1,1,1,4,4,4-hexafluoro-2-butene. [0003] The first route is the elimination method. Literature [A.I.Burmakov, L.A.Motnyak, B.V.Kunshenko, L.A.Alekseeva, L.M.Yagupolskii, Journal of Organic Chemistry USSR (English Translation), 1980,16,1204-1209.] reported 1,1,1,4,4,4-6 Fluorobutan-2-ol is eliminated in the presence of sulfur tetrafluoride to obtain E-1,1,1,4,4,4-hexafluoro-2-butene, Z-1,1,1,4,4 , 4-hexafluoro-2-butene and 1,1,1,2,4,4,4-heptafluorobutane, wherein, E-1,1,1,4,4,4-hexafluoro-2 - The yield of butene was only 37%. See reaction (1) for the ...

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Problems solved by technology

[0021] The above-mentioned prior art has the following problems: firstly, the raw materials of the first route are not easy to obtain, and the liquid phase method is adopted, a large amount of solvent is used, and a large amount of waste liquid and waste solid are produced; secondly, the raw materials of the second route are not easy to obtain, and the yield is low. Second, the yield of the third route is low; the fourth route is not only low in yield, but also easily produces a large amount of waste liquid and waste solid; the yield of the fifth route is too low; the sixth route Mid-ultraviolet irradiation is difficult to control, and the yield is low; the yield of ultraviolet irradiation in the seventh route is too low, and the method of using aluminum chlorofluoride as a catalyst is also difficult to control, Z-1, 1, 1, 4, 4, 4 - The boiling point of hexafluoro-2-butene is 33-33.5°C (760mmHg), which is very close to the reaction temperature (10°C to 24°C). It is easy to gasify and cause the reaction to go out of control. The above liquid phase method is difficult to achieve large-scale continuous production. E -1,1,1,4,4,4-hexafluoro-2-butene

The sulfur tetrafluoride used in the eighth route is a highly toxic substance, which is difficult to handle safely, and the yield of the target product is low

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