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Method for synthesizing fluorinated isobutene with hexafluoropropylene as starting material

A technology for fluoroisobutene and hexafluoropropene, which is applied in the field of gas-phase reaction for preparing fluoroisobutene, can solve the problems of low synthesis efficiency, prone to detonation, low initial reaction temperature, etc., and achieves high yield, long service life and high activity. high effect

Active Publication Date: 2021-07-09
泉州宇极新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The thermal cracking of perfluoroolefins has the following problems: 1) The cracking reaction temperature of tetrafluoroethylene is too high, which is prone to detonation; 2) The cracking of hexafluoropropylene has the disadvantage of low yield
The method of catalytic cracking of silica has the shortcoming that the reaction time is too long
The dehydrohalogenation route has the following disadvantages: 1) the gas-solid reaction produces a large amount of solid waste; 2) raw materials are difficult to obtain, and the yield of octafluoroisobutene is low
The de-halogenation route has the following disadvantages: 1) The liquid phase reaction process uses a large amount of solvent and reducing agent, which will generate liquid and solid waste; 2) Raw materials are difficult to obtain
Although this method does not use a reaction solvent and a reducing agent, the initial reaction temperature is very low and the yield of octafluoroisobutene is low, and there are disadvantages of high energy consumption and low synthesis efficiency
[0031] Up to now, there is no synthetic route of octafluoroisobutene in the public literature that satisfies the characteristics of easy availability of raw materials, high single-pass yield, and easy realization of gas-phase continuous production.

Method used

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  • Method for synthesizing fluorinated isobutene with hexafluoropropylene as starting material
  • Method for synthesizing fluorinated isobutene with hexafluoropropylene as starting material

Examples

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preparation example Construction

[0066] (1) Preparation of dehydrofluorination catalyst: Dissolve chromium trichloride in water, add concentrated ammonia water dropwise for precipitation, adjust the pH value to 7.5, then age for 24 hours, wash with water, filter, and dry in an oven at 120°C for 15 hours. The obtained solid was pulverized and pressed into tablets to obtain a catalyst precursor. Put 10mL of the catalyst precursor into a Monel tubular reactor with an inner diameter of 1 / 2 inch and a length of 30cm, and bake it at 350°C for 12 hours with nitrogen gas , nitrogen space velocity is 200h -1 , and then lower the temperature to 300°C, and at the same time pass a mixed gas composed of hydrogen fluoride and nitrogen with a mass ratio of 1:2, and the total space velocity of the gas is 220h -1 , activate for 12-24 hours, stop the above mixed gas, and make CrF 3 ; The activation time can be shortened, such as activation for 6-10 hours, to obtain chromium oxide fluoride CrO x f y (2x+y=3, and both x and y...

Embodiment 1

[0071] Prepare the block catalyst SbF in a tubular reactor made of Incon alloy with an inner diameter of 1 / 2 inch and a length of 30 cm 5 / MgF 2 (Mass percentages are 20%:80%) 10mL. The reaction conditions are as follows: the reaction temperature is 50° C., the mass ratio of hexafluoropropylene and trifluoromethane is 1:5, the contact time is 100 s, and the reaction pressure is 0.1 MPa. After running for 10 hours, the reaction product was washed with water, alkali and dried, and the organic phase was taken for GC analysis. The reaction results are: the conversion rate of hexafluoropropene is 65.3%, and the selectivity of 2-(difluoromethyl)-1,1,1,2,3,3,3-heptafluoropropane is 99.8%.

Embodiment 2

[0073] The prepared block catalyst SbF is filled in a tubular reactor made of Incon alloy with an inner diameter of 1 / 2 inch and a length of 30 cm. 5 / MgF 2 (Mass percentages are 20%:80%) 10mL. The reaction conditions are as follows: the reaction temperature is 100° C., the mass ratio of hexafluoropropylene and trifluoromethane is 1:5, the contact time is 100 s, and the reaction pressure is 0.1 MPa. After running for 10 hours, the reaction product was washed with water, alkali and dried, and the organic phase was taken for GC analysis. The reaction results are: the conversion rate of hexafluoropropene is 84.7%, and the selectivity of 2-(difluoromethyl)-1,1,1,2,3,3,3-heptafluoropropane is 99.6%.

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Abstract

The invention discloses a method for synthesizing fluorinated isobutene with hexafluoropropylene as a starting material, which comprises the following steps: (1) gas phase addition reaction: in the presence of a block catalyst, hexafluoropropylene and fluoromethane CHFXY(X , Y=F or H) undergoes gas phase addition to obtain (CF 3 ) 2 CFCHXY, (2) dehydrofluorination reaction: in the presence of dehydrofluorination catalyst, (CF 3 ) 2 CFCHXY is a raw material for dehydrofluorination reaction to obtain (CF 3 ) 2 C=CXY. Both the block catalyst and the dehydrofluorination catalyst in the invention have the characteristics of high activity and long service life, and can be used to produce fluorinated isobutene with high efficiency and continuous gas phase circulation.

Description

technical field [0001] The invention relates to a method for preparing fluorinated isobutene by gas phase reaction, in particular to a method for synthesizing fluorinated isobutene by using hexafluoropropylene and fluoromethane as starting materials through gas phase addition and dehydrofluorination in two steps. Background technique [0002] At present, the existing synthesis routes of octafluoroisobutene mainly include thermal cracking, catalytic cracking, dehydrohalogenation reaction, dedihalogenation reaction, isomerization reaction, Wittig reaction, etc. [0003] The first type of route: thermal cracking [0004] (1) Thermal cracking of polytetrafluoroethylene [0005] The literature "Analytical Chemistry. 1982, 54(14): 2607-2610" reported that in a closed tubular reactor, polytetrafluoroethylene was pyrolyzed at 500 ° C, and the reaction was 1 h, and the yield of octafluoroisobutene was 25 %. US2009149679 reported that in a horizontal tubular reactor, polytetrafluor...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C17/278C07C17/25C07C21/18C07C19/08B01J27/12B01J27/128B01J27/132B01J27/135B01J27/138
CPCB01J27/12B01J27/128B01J27/132B01J27/135B01J27/138C07C17/25C07C17/278C07C19/08C07C21/18
Inventor 张呈平庆飞要张妮权恒道
Owner 泉州宇极新材料科技有限公司
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