CN115611701A - A kind of method of synthesizing difluoro-bromopropene - Google Patents

Abstract

The invention relates to "a method for synthesizing difluoro-bromopropene", which belongs to the field of organic chemical synthesis. A method for synthesizing difluoro-bromopropene, characterized in that: bromotrifluoromethane (CF ₃ Br) and ethylene gas (CH ₂ =CH ₂ ) generate difluoro-bromopropene (molecular formula CF ₂ ) under the action of a catalyst Br-CH ₂ =CH ₂ ). CBrF ₃ +H ₂ C=CH ₂ →H ₂ C=CH-CF ₂ Br The invention has cheap raw materials and convenient sources; the catalyst has good stability and long service life; the separation and purification of products is simple; and industrial production is easy.

Description

A kind of method of synthesizing difluoro-bromopropene

technical field

The invention relates to a method for synthesizing difluoro-bromopropene, and relates to a method for synthesizing difluoro-bromopropene in an industrialized method.

Background technique

Difluorobromopropene (CAS: 460-33-3, 1-bromo-3,3,3-trifluoropropene) is a non-flammable bromofluoroolefin liquid with a boiling point of 40°C, low toxicity and low global Warming potential value, low ozone depletion potential value and other advantages. According to laboratory tests, after mixing 1-bromo-3,3,3-trifluoropropene with inert gas, the fire extinguishing effect is similar to that of BTP fire extinguishing agent. When mixed with dry powder fire extinguishers, it can effectively shorten the fire extinguishing time, and the use process is also safer and more reliable. With its safety, efficiency and environmental friendliness, 1-bromo-3,3,3-trifluoropropene has the potential to replace perfluorohexanone, heptafluoropropane and other clean fire extinguishing agents, and will have a large market in the future.

At present, the reports on the synthesis method of 1-bromo-3,3,3-trifluoropropene are relatively early, and there are very few domestic related studies. Patent (CN104936934A) reports a method of placing 3,3,3-trifluoropropyne in a Lewis acid environment, using hydrogen bromide as a catalyst, heating to 50-350°C for 2 hours, and then passing through -78°C A cooled trap collects the product. Under this method, the yield of 1-bromo-3,3,3-trifluoropropene is about 74%, but the product is accompanied by various by-products, such as 2-bromo-3,3,3-trifluoropropene and 1,2-dibromo-3,3,3-trifluoropropene, etc. The article (Journal of the American Chemical Society, 1952, vol.74, p.650) reported a method of mixing 3,3,3-trifluoropropyne with hydrogen bromide at 0°C to generate l-bromo-3, The method of 3,3-trifluoropropene, the yield of this method is between 83-91%, and the reaction temperature can be lowered to about -25°C by adding aluminum bromide. However, this method needs to be carried out in a low temperature environment, and the cost is high, so it is not suitable for commercial production.

In summary, in the existing synthetic routes of 1-bromo-3,3,3-trifluoropropene, there are characteristics such as harsh environmental requirements, high cost of raw materials involved, and low purity of products, which all limit 1-bromo-3,3,3-trifluoropropene. Industrial production of 3,3,3-trifluoropropene.

Contents of the invention

The object of the present invention is to utilize simple reaction system and suitable reaction condition to prepare tetrafluoro-bromobutene of high yield, the raw material of the present invention is cheap, source is convenient; Catalyst stability is good, service life is long; Product separation and purification are simple; Synthetic process is safe, Suitable for industrial production.

The present invention relates to a method for synthesizing difluoro-bromopropene, which is characterized in that: bromotrifluoromethane (CF ₃ Br) and ethylene gas (CH ₂ =CH ₂ ) generate difluoro-bromopropene ( Molecular formula CF ₂ Br-CH=CH ₂ )

Bromotrifluoromethane and ethylene gas generate difluorobromopropene under the action of a catalyst, and the catalyst is at least one of Mg, Mn, Fe, Pd, Al, or Mg, Mn, Fe, Pd, Al A composite formed of at least one of Bi, Ti, Ni and other metals.

Bromotrifluoromethane and ethylene gas generate difluorobromopropene under the action of catalyst, and the reaction temperature is -20-300°C.

Bromotrifluoromethane and ethylene gas generate difluorobromopropene under the action of a catalyst, and the molar ratio of bromotrifluoromethane and ethylene is 1:1-10.

Bromotrifluoromethane and ethylene gas generate difluorobromopropene under the action of a catalyst, and the contact time of the reaction is 1-20s.

The beneficial effects of the present invention are as follows:

1. The raw materials of the present invention are cheap and easy to source.

2. The catalyst has good stability and can be used repeatedly.

3. The separation and purification of the product is simple.

4. The synthesis process is safe and suitable for industrial production

detailed description

The present invention will be further illustrated below by describing specific embodiments, but this is not a limitation of the present invention. Those skilled in the art can make various modifications or improvements according to the basic idea of the present invention, but as long as they do not depart from the basic idea of the present invention , are within the scope of the present invention.

Example 1

Mix MgCl ₂ , Mn(NO ₃ ) ₂ , PdCl ₂ , and ZnCl ₂ solutions with a molar ratio of 50:40:5:5, and add 30 wt.% ammonia water dropwise to the mixed solution to adjust pH=11.0. The precipitate is filtered, washed with deionized water, dried, and pressed to form a catalyst precursor Mg-Mn-Pd-Zn. The specific surface area measured by BET method is 425m ² /g.

Add 50ml catalyst Mg-Mn-Pd-Zn precursor into the fixed bed reactor, and the fixed bed reactor is heated with an open tubular heating furnace. Under the protection of 100ml/min nitrogen, the catalyst was first raised to 200°C at 5°C/min, and dried at this temperature for 10 hours, and then the temperature was lowered to 100°C. This completes the catalyst drying process. The reactor was heated to 200°C and the catalyst was activated with 100 ml/min of pure hydrogen chloride for 10 hours. This completes the activation process of the Mg-Mn-Pd-Zn catalyst.

Heat the reactor to 150°C, and use a mass flow meter to feed 22.4ml/min of bromotrifluoromethane and 30ml/min of ethylene into the mixing chamber and mix evenly. After that, it goes through the reactor until the buffer bottle, water washing bottle, concentrated alkali absorber, and cooling collector. After the experiment, the product is mainly distributed in the cooling collector. The collected product was subjected to GC analysis. GC results showed that the collected product contained 45% difluoro-bromopropene.

Example 2

Mix MgCl ₂ , Mn(NO ₃ ) ₂ , BiCl ₃ , and FeCl ₃ solutions with a molar ratio of 50:40:5:5, and add 30 wt.% ammonia water dropwise to the mixed solution to adjust pH=11.0. The precipitate is filtered, washed with deionized water, dried, and pressed to form a catalyst precursor Mg-Mn-Bi-Fe. The specific surface area measured by BET method is 385m ² /g.

Add 50ml catalyst Mg-Mn-Bi-Fe precursor into the fixed bed reactor, and the fixed bed reactor is heated with an open tubular heating furnace. Under the protection of 100ml/min nitrogen, the catalyst was first raised to 200°C at 5°C/min, and dried at this temperature for 10 hours, and then the temperature was lowered to 100°C. This completes the catalyst drying process. The reactor was heated to 200°C and the catalyst was activated with 100 ml/min of pure hydrogen chloride for 10 hours. This completes the activation process of the Mg-Mn-Bi-Fe catalyst.

Heat the reactor to 250°C, and use a mass flow meter to feed 22.4ml/min of bromotrifluoromethane and 56.2ml/min of ethylene into the mixing chamber and mix evenly. After that, it goes through the reactor until the buffer bottle, water washing bottle, concentrated alkali absorber, and cooling collector. After the experiment, the product is mainly distributed in the cooling collector. The collected product was subjected to GC analysis. GC results showed that the collected product contained 65% difluoro-bromopropene.

Example 3

MgCl ₂ , Mn(NO ₃ ) ₂ , and FeCl ₃ solutions with a molar ratio of 50:30:20 were mixed, and 30 wt.% ammonia water was added dropwise to the mixed solution to adjust pH=11.0. The precipitate was filtered, washed with deionized water, dried, and pressed to obtain the catalyst precursor Mg-Mn-Fe. The specific surface area measured by BET method is 352m ² /g.

Add 50ml catalyst Mg-Mn-Fe precursor into the fixed bed reactor, and the fixed bed reactor is heated with an open tubular heating furnace. Under the protection of 100ml/min nitrogen, the catalyst was first raised to 200°C at 5°C/min, and dried at this temperature for 10 hours, and then the temperature was lowered to 100°C. This completes the catalyst drying process. The reactor was heated to 200°C and the catalyst was activated with 100 ml/min of pure hydrogen chloride for 10 hours. This completes the activation process of the Mg-Mn-Fe catalyst.

The reactor was heated to 180°C, and 22.4ml/min of bromotrifluoromethane and 32.6ml/min of ethylene were fed into the mixing chamber with a mass flow meter and mixed evenly. After that, it goes through the reactor until the buffer bottle, water washing bottle, concentrated alkali absorber, and cooling collector. After the experiment, the product is mainly distributed in the cooling collector. The collected product was subjected to GC analysis. GC results showed that the collected product contained 55% difluoro-bromopropene.

Claims (5)

1. A method for synthesizing difluorobromopropene is characterized by comprising the following steps: monobromotrifluoromethane (CF) ₃ Br) and ethylene gas (CH) ₂ ＝CH ₂ ) Generating difluorobromopropene (molecular formula CF) under the action of catalyst ₂ Br-CH＝CH ₂ )。

2. The method of claim 1, wherein the difluorobromopropene is produced from bromotrifluoromethane and ethylene gas over a catalyst selected from the group consisting of at least one of Mg, mn, fe, pd, and Al, or a composite of at least one of Mg, mn, fe, pd, and Al and one of Bi, ti, and Ni.

3. The process of claim 1, wherein the reaction temperature of bromotrifluoromethane and ethylene gas is-20 to 300 ℃ under the action of a catalyst to produce difluorobromopropene.

4. The method according to claim 1, wherein the difluorobromopropene is generated from bromotrifluoromethane and ethylene gas in the presence of a catalyst, and the molar ratio of the bromotrifluoromethane to the ethylene is 1: 1-10.

5. The process of claim 1, wherein the reaction contact time of the bromotrifluoromethane and the ethylene gas in the presence of the catalyst is 1-20s.