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Method for preparing fluorine-containing ethylene by catalytic cracking of 2-chloro-1,1-difluoroethane

A technology of difluoroethylene and difluoroethane, which is applied in the field of preparing fluorine-containing ethylene by catalytic cracking of 2-chloro-1,1-difluoroethane, can solve the problem of high reaction temperature, no industrial application value, high conversion rate and poor performance. Selectivity can not meet the requirements and other issues

Active Publication Date: 2020-02-11
SHANGHAI 3F NEW MATERIAL TECH CO LTD +1
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AI Technical Summary

Problems solved by technology

[0003] 2-Chloro-1,1-difluoroethane (R-142) is an isomer of 1-chloro-1,1-difluoroethane (R-142b) and is also used to produce R-142b industrially By-product, there is no direct industrial application value at present
The disadvantage of this method is that the reaction temperature is high and the energy consumption is large.
[0010] Although 2-chloro-1,1-difluoroethane (R-142) is an isomer of 1-chloro-1,1-difluoroethane (R-142b), simply using 1- The method for preparing 1,1-difluoroethylene from chloro-1,1-difluoroethane (R-142b) was transferred to 2-chloro-1,1-difluoroethane (R-142) Preparation of 1,1-difluoroethylene, as a result, the conversion and selectivity cannot meet the requirements

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  • Method for preparing fluorine-containing ethylene by catalytic cracking of 2-chloro-1,1-difluoroethane
  • Method for preparing fluorine-containing ethylene by catalytic cracking of 2-chloro-1,1-difluoroethane

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preparation example Construction

[0018] The preparation method of 1,1-difluoroethylene of the present invention comprises the steps:

[0019] (i) A catalytic cracking catalyst is provided, the catalyst includes fluoride carried on activated carbon, the weight ratio of the activated carbon to the fluoride is 1:0.01~0.5, and the fluoride is selected from aluminum fluoride, chromium fluoride , potassium fluoride, magnesium fluoride, calcium fluoride, or a mixture of two or more thereof;

[0020] The inventors of the present invention tried to use the ferric fluoride supported on activated carbon mentioned in the prior art as a catalyst (see CN109180420A) to catalytically crack 2-chloro-1,1-difluoroethane, but found that although the catalyst was used for cracking The conversion rate of R-142b is as high as 93% and the ratio of VDF / chlorofluoroethylene in the product is as high as 99:1, but when it is used for catalytic cracking of R-142, the conversion rate is lower than 40%, and the ratio of VDF / chlorofluoroeth...

Embodiment 1

[0055] 100ml of activated carbon-supported aluminum fluoride catalyst particles (the weight ratio of activated carbon to aluminum fluoride is 1:0.3) was loaded into a 10-liter reactor bed to form a catalytic cracking reactor. Prepare 2-chloro-1,1-difluoroethane and nitrogen gas at a molar ratio of 2-chloro-1,1-difluoroethane to nitrogen as 1:10 to form a mixed gas, which is preheated at 250°C After passing into the catalytic cracking reactor, the catalyst was activated at 260°C for 1.5 hours, and then at 400°C, normal pressure, 1000h -1 The reaction is carried out at a space velocity of .

[0056] The reacted gas is washed by the KOH lye absorption tower to remove HF and HCl gas, and then the nitrogen and 2-chloro-1,1-difluoroethane separated by the mixed gas rectification tower 1 are recycled, containing fluorine The ethylene product gas is rectified through the rectification tower 2 to obtain 1,1-difluoroethylene gas with a purity of more than 99.9%. The separated tail gas...

Embodiment 2

[0059] 100ml of activated carbon-supported aluminum fluoride catalyst particles (the weight ratio of activated carbon to aluminum fluoride is 1:0.3) was loaded into a 10-liter reactor bed to form a catalytic cracking reactor. The molar ratio of 2-chloro-1,1-difluoroethane to argon is 1:10 to prepare 2-chloro-1,1-difluoroethane and argon gas to form a mixed gas, and the mixed gas is heated at 250°C After preheating, pass it into the catalytic cracking reactor, activate the catalyst at 260°C for 1.5 hours, and then at 550°C, normal pressure, 1000h -1 Reaction is carried out under the space velocity of; Reaction aftertreatment is with embodiment 1, and the tail gas of catalytic cracking reactor is carried out gas chromatographic analysis in reaction process, analysis result is shown in Table 1.

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Abstract

The invention disclose a method for preparing fluorine-containing ethylene by catalytic cracking of 2-chloro-1,1-difluoroethane. The method comprises the following steps that (i), a catalytic crackingcatalyst is provided, wherein the catalyst comprises fluoride carried on active carbon, the weight ratio of the active carbon to the fluoride is 1 to (0.01-0.5), and the fluoride is selected from aluminum fluoride, chromium fluoride, potassium fluoride, magnesium fluoride, calcium fluoride, or a mixture of two or more of the aluminum fluoride, chromium fluoride, potassium fluoride, magnesium fluoride and calcium fluoride; (ii), the catalyst is loaded into a catalytic cracking reactor, a mixture of preheated inert gas and the 2-chloro-1,1-difluoroethane is introduced, and the catalyst is activated; and (iii), the mixture of preheated 2-chloro-1,1-difluoroethane and inert gas is introduced, the reaction temperature is 400-700 DEG C, space velocity is 200-3000h<-1>, pressure is 0.1-1.0Mpa, and 1,1-dichloroethylene is obtained.

Description

technical field [0001] The invention relates to a method for preparing fluorine-containing ethylene by catalytic cracking of 2-chloro-1,1-difluoroethane. The method of the invention has improved selectivity of fluorine-containing ethylene. Background technique [0002] Fluorinated ethylene has always been the core raw material monomer of fluoropolymer products, such as 1-fluoroethylene, 1,1-difluoroethylene, chlorotrifluoroethylene, trifluoroethylene, tetrafluoroethylene, etc. The annual global production capacity of 1,1-difluoroethylene reaches tens of thousands of tons, which is used to produce PVDF resin and mixed copolymer to produce fluororubber. PVDF resin is used in the production of various films, high-performance materials, adhesives and high-quality coatings. Viton has good heat resistance, corrosion resistance, aging resistance and excellent mechanical properties. In addition, 1,2-difluoroethylene and 2-chloro-1-fluoroethylene can also be used as monomers of flu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C17/25C07C21/18
CPCC07C17/25C07C21/18
Inventor 陈焱锋朱志荣杜丽君吴君毅
Owner SHANGHAI 3F NEW MATERIAL TECH CO LTD
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