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Method for preparing trans-1,3,3,3-tetrafluoropropene

A technology for tetrafluoropropene and pentafluoropropane is applied in the field of preparing trans-1,3,3,3-tetrafluoropropene, which can solve the problems of difficult recovery and achieve the effect of high reactivity

Active Publication Date: 2017-06-27
XIAN MODERN CHEM RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the above-mentioned preparation technology of E-HFO-1234ze, the alkali stripping method of HFC-245fa uses dimethyl sulfoxide, tetrahydrofuran and acetonitrile, which are easily soluble in water, as solvents. Such organic solvents are miscible with alkaline aqueous solution and are difficult to recover

Method used

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  • Method for preparing trans-1,3,3,3-tetrafluoropropene
  • Method for preparing trans-1,3,3,3-tetrafluoropropene

Examples

Experimental program
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Effect test

Embodiment 1

[0019] The reaction was carried out in a stirred 500mL stainless steel autoclave. 200g of 50% aqueous KOH solution, 200g of chlorobenzene, 1.2g of polyethylene glycol 2000 and 119g of HFC-245fa were successively dropped into the reactor, and the stirring was started, and the reaction temperature was raised to 70°C. After 60 minutes of reaction, the reaction temperature was maintained, from The gas phase port of the reactor slowly exhausted the reaction materials with low boiling points, collected them in cold hydrazine at -30°C, and analyzed the collected materials by gas chromatography. The results showed that the conversion rate of HFC-245fa was 95.9%, and the total selection of HFO-1234ze The specificity is 99.5%, and the selectivity of E-HFO-1234ze is 78.4%.

Embodiment 2

[0021] Example two is similar to example one, except that the aromatic hydrocarbon solvent chlorobenzene is not added, the reaction results show that the conversion rate of HFC-245fa is 20.1%, and the total selectivity of HFO-1234ze is 99.3%, wherein E-HFO-1234ze The selectivity is 75.2%. The results of Comparative Example 1 show that the dehydrofluorination activity of the alkaline aqueous solution is greatly improved after the addition of chlorobenzene.

Embodiment 3

[0023] The difference from Example 1 is that the chlorobenzene solvent in this example is the recovery solvent of Example 1, specifically: after the reaction solution in the kettle in Example 1 is lowered to room temperature, it is placed in a stratifier for phase separation, and the lower layer is removed. The organic phase is the chlorobenzene solvent. The recovered chlorobenzene is directly used in the reaction of this embodiment, and other operations remain unchanged. The reaction results show that the conversion rate of HFC-245fa is 95.8%, and the total selectivity of HFO-1234ze is 99.4%. The selection of E-HFO-1234ze The specificity is 79.1%, and the analysis result shows that the solvent can be recycled directly.

[0024] Embodiment four to six

[0025] The operation process of Examples 4-6 is similar to that of Example 1, the difference is that the solvent is changed, and the reaction results are shown in Table 1.

[0026] Table 1

[0027]

[0028] Note: X 245fa...

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Abstract

The invention discloses a method for preparing trans-1,3,3,3-tetrafluoropropene. The method comprises the following step: in the presence of a phase transfer catalyst and an aromatic hydrocarbon solvent, performing dehydrofluorination reaction on 1,1,1,3,3-perfluoropropane and an alkali solution, thereby obtaining trans-1,3,3,3-tetrafluoropropene, wherein the reaction temperature is 30-100 DEG C, the reaction time is 10-120 minutes, the phase transfer catalyst is crown ether or polyalkylene glycol, the aromatic hydrocarbon solvent is chlorinated benzene or alkylbenzene, and the alkali solution is a solution of sodium hydroxide or a solution of potassium hydroxide. By adopting the method, a two-phase dehydrofluorination system consisting of the alkali solution and the aromatic hydrocarbon solvent is established; in the presence of the phase transfer solvent, trans-1,3,3,3-tetrafluoropropene is prepared from 1,1,1,3,3-perfluoropropane; and the method has the advantages that the conversion rate is high and the solvent can be repeatedly used.

Description

technical field [0001] The present invention relates to a method for preparing trans-1,3,3,3-tetrafluoropropene, especially a method for producing 1,1,1,3,3-pentafluoropropane in the presence of a phase transfer catalyst and an aromatic hydrocarbon solvent A method for preparing trans-1,3,3,3-tetrafluoropropene by dehydrofluorination reaction with alkaline aqueous solution. Background technique [0002] The ozone depletion value (ODP) of trans-1,3,3,3-tetrafluoropropene (E-HFO-1234ze) is 0, and the greenhouse effect potential value (GWP) is 6, which is recognized by the international community as a high GWP Ideal low-carbon and environmentally friendly substitutes for hydrofluorocarbons (HFCs), such as blowing agents to replace 1,1,3,3,3-pentafluoropropane (HFC-245fa), 1,1,1,2-tetrafluoroethane Alkanes (HFC-134a) and 1,1-difluoroethane (HFC-152a), as an aerosol propellant to replace HFC-134a, etc. [0003] Chinese patent CN104177219A reports that in the presence of solvent...

Claims

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Application Information

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IPC IPC(8): C07C17/25C07C21/18
Inventor 张伟李宝太曾纪珺马家琪韩升焦锋刚唐晓博聂剑飞吕剑尹双良孟庆宇武海涛
Owner XIAN MODERN CHEM RES INST
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