Method for preparing hexafluoro-1,3-butadiene

A technology for catalytic preparation of -butadiene, which is applied in the direction of dehalogenation preparation, dehydrohalogenation preparation, chemical instruments and methods, etc., can solve the problems of harsh reaction conditions, high raw material prices, and difficult handling of reagents, and achieve low cost, The effect of high yield and few steps

Active Publication Date: 2017-03-15
湖北广钢气体电子材料有限公司
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Its advantages are short steps, simple process, and few by-products; but there are also disadvantages such as hi

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  • Method for preparing hexafluoro-1,3-butadiene

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[0040] (2) The method for preparing hexafluoro-1,3-butadiene provided by the present invention overcomes the disadvantages of long operation period and low yield per unit volume of the existing process, and has high yield, few steps and easy industrialization. Through the selection of reactants and the control of reaction conditions, the production of high-purity hexafluoro-1,3-butadiene can be realized.

[0041] Further, in step 1, in terms of mass ratio, solvent: zinc powder=1.5~4:1; in terms of molar ratio, zinc powder: 1,2-dichloro-1,1,2-trifluoroethane= 1 to 2:1, more preferably 1 to 1.5:1.

[0042] Further, the solvent is selected from one of tetrahydrofuran, acetonitrile and N,N-dimethylformamide.

[0043] Further, the zinc powder was pretreated with 10wt% hydrochloric acid solution for 20 minutes before being loaded into the reactor, washed with absolute ethanol, and then dried at 100°C.

[0044] Further, in step 1, the reaction temperature is 60-80° C., and the reac...

Embodiment 1

[0057] Example 1 Preparation of CHF=CF from 1,2-dichloro-1,1,2-trifluoroethane 2 and CBrF 2 CHBrF

[0058] Using 1,2-dichloro-1,1,2-trifluoroethane as raw material, CHF=CF was prepared by liquid-phase dechlorination reaction 2 . 200g of zinc powder was pretreated with 10% hydrochloric acid solution for 20min, washed with absolute ethanol, and dried at 100°C. Put the treated Zn into a stainless steel reactor with stirring, and feed N 2 Purge for 0.5h. Add 400g of tetrahydrofuran solvent into the reaction kettle, and start stirring. Then gradually feed 600g of 1,2-dichloro-1,1,2-trifluoroethane under stirring, raise the temperature of the reactor to 70°C under stirring, react for 1 hour, and take samples after the reactor is naturally cooled Analysis, the conversion rate of 1,2-dichloro-1,1,2-trifluoroethane is 94.3%, CHF=CF 2 The selectivity is 98.2%. The gas produced by the reaction is washed with water, washed with alkali, and passed into liquid bromine. After the rea...

Embodiment 2

[0059] Example 2 Preparation of CHF=CF from 1,2-dichloro-1,1,2-trifluoroethane 2 and CBrF 2 CHBrF

[0060] Using 1,2-dichloro-1,1,2-trifluoroethane as raw material, CHF=CF was prepared by liquid-phase dechlorination reaction 2 . 300g of zinc powder is put into a stainless steel reaction kettle with stirring, and N 2 Purge for 0.5h. 500g of acetonitrile solvent was added to the reaction kettle, and the stirring was started. Then gradually feed 600g of 1,2-dichloro-1,1,2-trifluoroethane under stirring, raise the temperature of the reactor to 80°C under stirring, react for 2 hours, and take samples after the reactor cools naturally Analysis, the conversion rate of 1,2-dichloro-1,1,2-trifluoroethane is 96.5%, CHF=CF 2 The selectivity is 97.8%. The gas produced by the reaction is washed with water, washed with alkali, and passed into liquid bromine. After the reaction is complete, the color of liquid bromine gradually becomes lighter from brown, CHF=CF 2 and Br 2 Complete ...

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Abstract

The invention relates to a method for preparing hexafluoro-1,3-butadiene. The method comprises the following steps: performing reduction dechloridation on 1,2-dichloro-1,1,-2-halothane with zinc powder to obtain a CF2=CHF gas phase intermediate product, introducing into liquid bromine to carry out an addition reaction, and obtaining CBrF2CHBrF; evaporating CBrF2CHBrF in an evaporator to generate a gas, and using a reaction tube filled with a first catalyst to remove one molecule HBr and generate trifluorovinyl bromide; performing two steps of reactions on the trifluorovinyl bromide under the action of the zinc powder, the solvent and a second catalyst, thereby obtaining the hexafluoro-1,3-butadiene. The method has the advantages of being simple in process, high in yield, easy in raw material obtaining, easy in industrialization, green and environment-friendly.

Description

technical field [0001] The invention relates to the technical field of chlorofluoroolefin preparation, in particular to a method for preparing hexafluoro-1,3-butadiene through catalytic hydrogenation dechlorination dimerization. Background technique [0002] Hexafluoro-1,3-butadiene is a liquefied gas with the molecular formula C 4 f 6 , molecular weight 162, melting point -132°C, boiling point 6°C, critical temperature 140°C, gas phase density (relative to air) 6.79, combustion range 7% to 73%, and its main application is plasma etching processing medium for semiconductor products. Compared with traditional plasma etching gas CF 4 、C 2 f 6 、C 3 f 8 , c-C 4 f 8 and NF 3 Compared to C 4 f 6 It has the characteristics of faster etch rate, high etch selectivity and high aspect ratio. C 4 f 6 There are many advantages in etching at the technical level of 0.13μm, which is better than C 4 f 8 It has a higher selectivity ratio to photoresist and silicon nitride, whi...

Claims

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Application Information

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IPC IPC(8): C07C17/269C07C21/20
CPCC07C17/04C07C17/23C07C17/25C07C17/269C07C21/20C07C21/18
Inventor 陈岩飞王聪海肖晓明
Owner 湖北广钢气体电子材料有限公司
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