Continuous preparation method of 1, 2-dichloro-3, 3, 3-trifluoropropene

Abstract

The invention discloses a continuous preparation method of 1, 2-dichloro-3, 3, 3-trifluoropropene, and belongs to the technical field of organic fluorine chemical industry. The invention relates to a method for preparing 1, 2-dichloro-3, 3, 3-trifluoropropene through continuous reaction by taking 3, 3, 3-trifluoropropyne and chlorine as initial raw materials in the presence of a Fe-Mn-K-Al2O3 catalyst. The invention provides a novel continuous preparation route of the 1, 2-dichloro-3, 3, 3-trifluoropropene, and relates to a preparation method of the 1, 2-dichloro-3, 3, 3-trifluoropropene. The raw material of the 1, 3, 3, 3-trifluoropropyne is one of high-boiling-point components in industrial production of the product monochlorotrifluoropropene of a company, and is easy to obtain; the continuous preparation method of the 1, 2-dichloro-3, 3, 3-trifluoropropene, provided by the invention, has the advantages of low raw material cost, less three wastes, easiness in industrialization and the like.

Description

Technical Field

[0001] The invention discloses a continuous preparation method of 1,2-dichloro-3,3,3-trifluoropropene, belonging to the technical field of organic fluorine chemical industry, and specifically is a preparation method of 1,2-dichloro-3,3,3-trifluoropropene with 3,3,3-trifluoropropyne as a starting material. Background Art

[0002] In recent years, it has been widely recognized that fully halogenated chlorofluorocarbons (CFCs) pose a serious threat to the Earth's ozone layer. As a result, the fluorocarbon industry has shifted its attention to developing safer alternative materials containing less or no chlorine substitution, such as hydrochlorofluoroolefins (HCFOs), hydrofluorocarbons (HFCs), and hydrofluoroolefins (HFOs).

[0003] 1,2-Dichloro-3,3,3-trifluoropropene (HCFO-1223xd) can be used as a raw material and intermediate for the preparation of various fluorocarbons, such as cis-1,1,1,4,4,4-hexafluoro-2-butene (cis-HCFO-1336), 1,1,1,3,3-pentafluoropropane (HFC-245fa), 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,3,3,3-tetrafluoropropene (HFO-1234ze). It can also be used as a fluorinated monomer for the production of polymers. In addition, it can also be used as a raw material for introducing CF3 group structural blocks into fluorinated functional materials and as a pharmaceutical intermediate.

[0004] WO9745388 discloses a method for preparing HFC-245fa by reacting chlorofluoropropane with antimony fluoride. HCFO-1223xd is a product with a content ranging from 0.2 to 13.3%, and has low selectivity and conversion rate.

[0005] US2009043118 discloses a method for generating a composition containing HFO-1234yf, 2,3-dichloro-1,1,1-trifluoropropane (HCFC-243db), 2-chloro-1,1,1-trifluoropropene (HCFO-1233xf), 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and HCFO-1223xd, which can be used as a heat transfer composition, by reacting 3,3,3-trifluoropropene (HFO-1243zf) with hydrogen fluoride and chlorine in the presence of a gas phase fluorination catalyst. In the reaction, the content of the generated HCFO-1223xd varies in the range of 0 to 20.2%, with low selectivity and low conversion rate.

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a continuous preparation method of 1,2-dichloro-3,3,3-trifluoropropene to solve the technical problems of the reaction conditions of the preparation method in the prior art being not mild enough and the selectivity being not high. Through long-term experiments and explorations, a method for continuously preparing 1,2-dichloro-3,3,3-trifluoropropene using 3,3,3-trifluoropropyne and chlorine as raw materials in the presence of a Fe-Mn-K-Al2O3 catalyst was found. Summary of the invention

[0007] The object of the present invention is to provide a new method for continuously preparing 1,2-dichloro-3,3,3-trifluoropropene with low raw material cost, few by-products and high yield.

[0008] To achieve the purpose of the invention, the technical scheme adopted by the present invention is: a method for continuously synthesizing 1,2-dichloro-3,3,3-trifluoropropene, a method for continuously preparing 1,2-dichloro-3,3,3-trifluoropropene using 3,3,3-trifluoropropyne and chlorine as starting materials in the presence of a Fe-Mn-K-Al2O3 catalyst. The method has the advantages of low raw material cost, high product purity, and easy industrial production.

[0009] Specifically, a method for preparing 1,2-dichloro-3,3,3-trifluoropropene by continuous reaction in the presence of a Fe-Mn-K-Al2O3 catalyst using 3,3,3-trifluoropropyne and chlorine as starting materials.

[0010] Specifically, the Fe-Mn-K-Al2O3 catalyst is prepared as follows:

[0011] (1) Prepare an aqueous solution of iron salt, and use alumina as a carrier to impregnate the aqueous solution by unsaturated impregnation method. After drying the filtered precursor in an oven at 120°C for 10 hours, calcine it at 150-500°C in air for 3-5 hours. The calcined precursor is reduced in an anhydrous hydrogen fluoride atmosphere at 200°C-350°C for 72 hours.

[0012] (2) The reduced precursor is saturatedly co-impregnated with a mixed solution containing additives of manganese and potassium, dried and calcined, and then unsaturatedly spray-impregnated with a metal additive potassium solution, and then dried and calcined to obtain a Fe-Mn-K-Al2O3 catalyst.

[0013] Specifically, the iron salt in step (1) is one or more of ferric chloride, ferric nitrate or ferric bromide.

[0014] Specifically, in step (1), the impregnation amount is 5%-60% of the saturated absorption solution of the alumina carrier, the impregnation time is 1h-8h, and the impregnation temperature is 30°C-70°C.

[0015] The impregnation amount is controlled at 5%-60% of the saturated absorption solution of the alumina carrier, which can ensure that the loading amount of the active components in the Fe-Mn-K-Al2O3 catalyst is moderate, and the catalytic activity will not be affected by too little loading, nor will the carrier pores be blocked due to too much loading, thereby reducing the specific surface area and mass transfer performance of the Fe-Mn-K-Al2O3 catalyst. The impregnation time is 1h~8h and the impregnation temperature is 30℃~70℃, which can make the active components fully interact with the carrier, achieve uniform loading, and improve the stability and service life of the Fe-Mn-K-Al2O3 catalyst.

[0016] Specifically, in step (2), the potassium source of the auxiliary potassium is one or more of potassium nitrate, potassium bromide and potassium chloride, and the manganese source of the auxiliary manganese is manganese nitrate or manganese chloride.

[0017] One or more of potassium nitrate, potassium bromide, and potassium chloride are used as potassium sources, and manganese nitrate or manganese chloride is used as a manganese source. These compounds can synergize with other components in the reaction to adjust the activity and selectivity of the catalyst. At the same time, these compounds are relatively easy to obtain and have low costs, which is conducive to reducing the cost of the production process.

[0018] Specifically, the raw material adopts a gas mass flow meter to control the feed quality. The use of a gas mass flow meter to control the feed quality can achieve accurate measurement of the raw materials and ensure that the proportion of each component in the reaction system is accurate and stable. This helps to improve the selectivity and yield of the reaction, reduce the occurrence of side reactions, and also facilitates the optimization and control of the reaction process.

[0019] Specifically, the reaction temperature is 150°C to 250°C. Controlling the reaction temperature within the range of 150°C to 250°C can provide sufficient activation energy for the reaction and promote the reaction of 3,3,3-trifluoropropene and chlorine. At the same time, this temperature range can also avoid problems such as increased side reactions caused by excessively high temperatures and deactivation of the Fe-Mn-K-Al2O3 catalyst, thereby ensuring the selectivity and stability of the reaction.

[0020] Specifically, the molar ratio of 3,3,3-trifluoropropene to chlorine is 0.8-1.2:1.

[0021] Specifically, unreacted 3,3,3-trifluoropropyne is separated and then used again.

[0022] Specifically, the reaction contact time is 10s to 100s.

[0023] Compared with the prior art, the continuous preparation method of 1,2-dichloro-3,3,3-trifluoropropene of the present invention has the following beneficial effects: the present invention provides a new continuous preparation route of 1,2-dichloro-3,3,3-trifluoropropene; the 3,3,3-trifluoropropyne raw material is one of the high-boiling components of the industrial production of the company's product monochlorotrifluoropropene, and the raw material is easy to obtain; the continuous preparation method of 1,2-dichloro-3,3,3-trifluoropropene provided by the present invention has the advantages of low raw material cost, less three wastes, easy industrialization, etc. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited to these embodiments. Those skilled in the art should recognize that the present invention covers all possible alternatives, improvements and equivalents within the scope of the claims.

[0025] Fe-Mn-K-Al2O3 catalyst A is prepared as follows:

[0026] (1) Prepare an aqueous solution of ferric bromide, and use an unsaturated impregnation method to impregnate the aqueous solution with alumina as the carrier. The impregnation amount is 25% of the saturated absorption amount of the alumina carrier, the impregnation time is 6 hours, and the impregnation temperature is 50°C. Filter the precursor, dry the precursor in an oven at 120°C for 10 hours, and then calcine it at 350°C in air for 4 hours. The calcined precursor is reduced at 300°C in an anhydrous hydrogen fluoride atmosphere for 72 hours;

[0027] (2) The reduced precursor is saturatedly co-impregnated with a mixed solution containing manganese chloride and potassium bromide, dried and calcined, and then unsaturatedly spray-impregnated with a metal additive potassium solution, and then dried and calcined. The drying and calcination conditions are the same as those in step (1) to obtain Fe-Mn-K-Al2O3 catalyst A.

[0028] Fe-Mn-K-Al2O3 catalyst B is prepared as follows:

[0029] (1) Prepare an aqueous solution of ferric chloride, and use an unsaturated impregnation method to impregnate the aqueous solution with alumina as the carrier. The impregnation amount is 5% of the saturated absorption amount of the alumina carrier, the impregnation time is 8 hours, and the impregnation temperature is 30°C. Filter the precursor, dry the precursor in an oven at 120°C for 10 hours, and then calcine it at 150°C in air for 5 hours. The calcined precursor is reduced at 200°C in an anhydrous hydrogen fluoride atmosphere for 72 hours;

[0030] (2) The reduced precursor is saturatedly co-impregnated with a mixed solution containing manganese chloride and potassium nitrate, dried and calcined, and then unsaturatedly spray-impregnated with a metal additive potassium solution, and then dried and calcined. The drying and calcination conditions are the same as those in step (1) to obtain a Fe-Mn-K-Al2O3 catalyst.

[0031] Fe-Mn-K-Al2O3 catalyst C is prepared as follows:

[0032] (1) Prepare an aqueous solution of ferric nitrate, and use an unsaturated impregnation method to impregnate the aqueous solution with alumina as a carrier, the impregnation amount is 60% of the saturated absorption amount of the alumina carrier, the impregnation time is 1 hour, and the impregnation temperature is 70°C. Filter to obtain a precursor, dry the precursor in an oven at 120°C for 10 hours, and then calcine it at 500°C in air for 3 hours. The calcined precursor is reduced at 350°C in an anhydrous hydrogen fluoride atmosphere for 72 hours;

[0033] (2) The reduced precursor is saturatedly co-impregnated with a mixed solution containing manganese nitrate and potassium nitrate, dried and calcined, and then unsaturatedly spray-impregnated with a metal additive potassium solution, and then dried and calcined. The drying and calcination conditions are the same as those in step (1) to obtain a Fe-Mn-K-Al2O3 catalyst.

[0034] Example 1

[0035] In a 316L stainless steel fixed bed reactor with an inner diameter of 38mm, 60ml of self-made Fe-Mn-K-Al2O3 catalyst was loaded, and Fe-Mn-K-Al2O3 catalyst A was dried, preheated and activated. After activation, 3,3,3-trifluoropropene and chlorine were introduced at 200°C to react under normal pressure, and the molar ratio of the two was controlled to be 1:1, and the contact time was 100 seconds. After washing with water and alkali, the product was detected by gas chromatography, and the content of 1,2-dichloro-3,3,3-trifluoropropene was 97%, 3,3,3-trifluoropropyne was 1%, and there were a small amount of impurities.

[0036] Example 2

[0037] In a 316L stainless steel fixed bed reactor with an inner diameter of 38mm, 60ml of self-made Fe-Mn-K-Al2O3 catalyst was loaded, and Fe-Mn-K-Al2O3 catalyst B was dried, preheated and activated. After activation, 3,3,3-trifluoropropene and chlorine were introduced at 200°C to react under normal pressure, and the molar ratio of the two was controlled to be 1:1, and the contact time was 100 seconds. After washing with water and alkali, the product was detected by gas chromatography, and the content of 1,2-dichloro-3,3,3-trifluoropropene was 94%, 3,3,3-trifluoropropyne was 3.5%, and there were a small amount of impurities.

[0038] Example 3

[0039] In a 316L stainless steel fixed bed reactor with an inner diameter of 38mm, 60ml of self-made Fe-Mn-K-Al2O3 catalyst was loaded, and Fe-Mn-K-Al2O3 catalyst A was dried, preheated and activated. After activation, 3,3,3-trifluoropropene and chlorine were introduced at 250°C to react under normal pressure, and the molar ratio of the two was controlled to be 1:1, and the contact time was 10 seconds. After washing with water and alkali, the product was detected by gas chromatography, and the content of 1,2-dichloro-3,3,3-trifluoropropene was 93%, 3,3,3-trifluoropropyne was 3%, and there were a small amount of impurities.

[0040] Example 4

[0041] In a 316L stainless steel fixed bed reactor with an inner diameter of 38mm, 60ml of self-made Fe-Mn-K-Al2O3 catalyst was loaded, and Fe-Mn-K-Al2O3 catalyst B was dried, preheated and activated. After activation, 3,3,3-trifluoropropene and chlorine were introduced at 200°C to react under normal pressure, and the molar ratio of the two was controlled to be 0.8:1, and the contact time was 50 seconds. After washing with water and alkali, the product was detected by gas chromatography, and the content of 1,2-dichloro-3,3,3-trifluoropropene was 89%, 3,3,3-trifluoropropyne was 9%, and there were a small amount of impurities.

[0042] Example 5

[0043] In a 316L stainless steel fixed bed reactor with an inner diameter of 38mm, 60ml of self-made Fe-Mn-K-Al2O3 catalyst was loaded, and Fe-Mn-K-Al2O3 catalyst A was dried, preheated and activated. After activation, 3,3,3-trifluoropropene and chlorine were introduced at 150°C to react under normal pressure, and the molar ratio of the two was controlled to be 1:1, and the contact time was 10 seconds. After washing with water and alkali, the product was detected by gas chromatography, and the content of 1,2-dichloro-3,3,3-trifluoropropene was 85%, 3,3,3-trifluoropropyne was 14%, and there were a small amount of impurities.

[0044] Example 6

[0045] In a 316L stainless steel fixed bed reactor with an inner diameter of 38mm, 60ml of self-made Fe-Mn-K-Al2O3 catalyst was loaded, and Fe-Mn-K-Al2O3 catalyst C was dried, preheated and activated. After activation, 3,3,3-trifluoropropene and chlorine were introduced at 230°C to react under normal pressure, and the molar ratio of the two was controlled to be 1.2:1, and the contact time was 50 seconds. After washing with water and alkali, the product was detected by gas chromatography, and the content of 1,2-dichloro-3,3,3-trifluoropropene was 81%, 3,3,3-trifluoropropyne was 15%, and there were a small amount of impurities.

[0046] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A continuous method for preparing 1,2-dichloro-3,3,3-trifluoropropene, characterized in that: The invention discloses a method for preparing 1,2-dichloro-3,3,3-trifluoropropene by continuous reaction with 3,3,3-trifluoropropyne and chlorine as starting materials in the presence of Fe-Mn-K-Al2O3 catalyst.

2. According to claim 1, a continuous method for preparing 1,2-dichloro-3,3,3-trifluoropropene, characterized in that: The Fe-Mn-K-Al2O3 catalyst was prepared as follows: (1) preparing an aqueous solution of iron salt, using alumina as a carrier to impregnate the aqueous solution by unsaturated impregnation method, and then filtering to obtain a precursor, drying the precursor in an oven at 120°C for 10 hours, calcining the precursor at 150°C-500°C in air for 3 hours to 5 hours, and reducing the calcined precursor at 200°C-350°C in an anhydrous hydrogen fluoride atmosphere for 72 hours; (2) The reduced precursor is saturatedly co-impregnated with a mixed solution containing additives of manganese and potassium, dried and calcined, and then unsaturatedly spray-impregnated with a metal additive potassium solution, and then dried and calcined to obtain a Fe-Mn-K-Al2O3 catalyst.

3. A method for preparing 1,2-dichloro-3,3,3-trifluoropropene in a continuous process according to claim 2, characterized in that: In step (1), the iron salt is one or more of ferric chloride, ferric nitrate or ferric bromide.

4. A continuous method for preparing 1,2-dichloro-3,3,3-trifluoropropene according to claim 2, characterized in that: In step (1), the impregnation amount is 5%-60% of the saturated absorption solution of the alumina carrier, the impregnation time is 1h-8h, and the impregnation temperature is 30°C-70°C.

5. A continuous method for preparing 1,2-dichloro-3,3,3-trifluoropropene according to claim 2, characterized in that: In step (2), the potassium source of the potassium auxiliary agent is one or more of potassium nitrate, potassium bromide and potassium chloride, and the manganese source of the manganese auxiliary agent is manganese nitrate or manganese chloride.

6. A continuous method for preparing 1,2-dichloro-3,3,3-trifluoropropene according to claim 1, characterized in that: The feed quality of the starting materials was controlled by a gas mass flow meter.

7. A continuous method for preparing 1,2-dichloro-3,3,3-trifluoropropene according to claim 1, characterized in that: The reaction temperature is 150℃~250℃.

8. A continuous method for preparing 1,2-dichloro-3,3,3-trifluoropropene according to claim 1, characterized in that: The molar ratio of 3,3,3-trifluoropropene to chlorine is 0.8~1.2:

1.

9. A continuous method for preparing 1,2-dichloro-3,3,3-trifluoropropene according to claim 1, characterized in that: The unreacted 3,3,3-trifluoropropyne can be separated and reused.

10. A continuous method for preparing 1,2-dichloro-3,3,3-trifluoropropene according to claim 1, characterized in that: The reaction contact time is 10s~100s.