Supported catalyst as well as preparation method and application thereof

Abstract

The invention discloses a supported catalyst and application thereof in synthesis of difluoroacetyl fluoride, the supported catalyst comprises a carrier and active components, the active components comprise superacid and an active auxiliary agent; in the supported catalyst, the loading capacity of the superacid is 20 wt%-25 wt%, and the loading capacity of the active auxiliary agent is 5 wt%-10 wt%; the superacid is selected from at least one of fluoboric acid, fluorosulfonic acid, fluoroantimonic acid and carborane acid; the active auxiliary agent is selected from at least one of molybdenum nitrate, technetium nitrate, ruthenium nitrate, rhodium nitrate and chromic nitrate; when the supported catalyst is used for synthesizing difluoroacetyl fluoride, 1, 1, 2, 2-tetrafluoroethyl ethyl ether is used as a raw material, hydrogen fluoride is added under the action of the supported catalyst to inhibit generation of ethylene, and difluoroacetyl fluoride and fluoroethane are generated through cracking under relatively mild conditions; compared with an existing preparation method, the conditions are milder, and the one-way yield is larger than 95%.

Description

Technical Field

[0001] This invention relates to the field of supported catalysts and organic synthesis technology, and more specifically to a supported catalyst, its preparation method, and its application. Background Technology

[0002] Difluoroacetyl fluoride (CAS No. 2925-22-6) is an important organic synthesis intermediate, widely used in the synthesis of pharmaceuticals, pesticides, and fine chemicals. Currently, there are two main methods for synthesizing difluoroacetyl fluoride: (1) Japanese patent document JP2011168564, Korean patent document KR1789771, and European patent document EP0694523 report methods for preparing difluoroacetyl fluoride using tetrafluoroethyl ether; (2) WO2009115426 reports a method for preparing difluoroacetyl fluoride using dichloroacetyl chloride, with the following reaction formula:

[0003] Both of the above methods have relatively harsh requirements for the preparation of raw materials and the final fluorination reaction conditions. They often need to be carried out in a high-temperature environment above 200°C, which makes the operation difficult and the cost high.

[0004] If the reaction is carried out using the catalyst in the existing process, fluoroethane will continue to crack into ethylene, resulting in a huge waste of the product's added value. Summary of the Invention

[0005] The purpose of this invention is to provide a supported catalyst, its preparation method, and its application to solve the above-mentioned problems. The supported catalyst provided by this invention, when used in the synthesis of difluoroacetyl fluoride, can ensure high selectivity of the cracking reaction by adding hydrogen fluoride to inhibit the formation of ethylene.

[0006] To achieve the above objectives, the present invention specifically adopts the following technical solution: The first aspect of this invention provides a supported catalyst, comprising a support and an active component, wherein the active component comprises a superacid and an active promoter; wherein the supported catalyst has a superacid loading of 20wt% to 25wt% and an active promoter loading of 5wt% to 10wt%; the superacid is selected from at least one of fluoroboric acid, fluorosulfonic acid, fluoroantimonyic acid, and carboraneic acid; and the active promoter is selected from at least one of molybdenum nitrate, technetium nitrate, ruthenium nitrate, rhodium nitrate, and chromium nitrate.

[0007] Furthermore, the carrier is selected from at least one of alumina, silica gel, and pumice.

[0008] Furthermore, the specific surface area of ​​the carrier is 50 m². 2 / g~700m 2 / g, preferably 200m2 / g~600m 2 / g.

[0009] A second aspect of the present invention provides a method for preparing the above-mentioned supported catalyst, comprising: impregnating a support with a solution containing an active component.

[0010] Furthermore, in the solution containing the active component, the active component includes a superacid and an active auxiliary agent, wherein the mass ratio of the superacid and the active auxiliary agent is (2-5):1.

[0011] Furthermore, the mass ratio of the active component to the carrier is (5-7):20.

[0012] Furthermore, the solvent in the solution containing the active component is selected from at least one of carbon tetrachloride, chloroform, and sulfolane; the amount of solvent used is 30 to 100 times the mass of the active component.

[0013] Furthermore, the impregnation conditions include: impregnation time of 10 to 15 hours under reflux conditions; Preferably, the impregnation process further includes filtration, vacuum drying, and calcination; More preferably, the vacuum drying temperature is 50℃~60℃; and / or the calcination conditions include: a calcination temperature of 400℃~500℃ and a calcination time of 4 hours~5 hours.

[0014] A third aspect of the present invention provides a method for synthesizing difluoroacetyl fluoride, comprising: in the presence of a protective gas, 1,1,2,2-tetrafluoroethyl ether is cracked to obtain difluoroacetyl fluoride under the action of the above-described supported catalyst or the supported catalyst prepared by the above-described preparation method, wherein the protective gas is selected from hydrogen fluoride.

[0015] The reaction pathway for the synthesis of difluoroacetyl fluoride is as follows: .

[0016] In this invention, the protective gas can prevent the byproduct fluoroethane from cracking into ethylene and hydrogen fluoride, and avoid hydrogen fluoride from corroding the equipment. The protective gas can also be diluted with inert gases (such as nitrogen, argon, and helium), but the effect is not obvious. The main reason for choosing hydrogen fluoride in this invention is to inhibit the cracking of fluoroethane.

[0017] Further, the feed rate of the 1,1,2,2-tetrafluoroethyl ether is 0.2 g / min to 1.4 g / min, preferably 0.4 g / min to 0.8 g / min; And / or, the flow rate of the protective gas is 40 mL / min to 170 mL / min, preferably 120 mL / min to 160 mL / min; And / or, the pyrolysis conditions include: a temperature of 150°C to 300°C, preferably 150°C to 180°C, and a volume hourly space velocity of 120 h⁻¹. -1 ~900h -1 .

[0018] Furthermore, the supported catalyst also includes a fluorination process; Preferably, the fluorination process includes: fluorinating the above-mentioned supported catalyst or the supported catalyst prepared by the above-mentioned preparation method in a fluorinating gas; More preferably, the fluorinating gas is selected from at least one of hydrogen fluoride and chlorofluoromethane; the fluorination conditions include: a fluorination temperature of 200℃ to 400℃ and a fluorination time of 12 hours to 20 hours.

[0019] Beneficial effects: This invention provides a process for synthesizing difluoroacetyl fluoride using a supported catalyst. The process uses 1,1,2,2-tetrafluoroethyl ether as a raw material. Under the action of the supported catalyst, hydrogen fluoride is added to inhibit ethylene formation, and the fluoride is decomposed under relatively mild conditions to produce difluoroacetyl fluoride and fluoroethane. Compared with existing preparation methods (which have reaction temperatures >200℃, single-pass yields >95%, and most of the generated fluoroethane decomposes into ethylene and hydrogen fluoride), the process is milder, with a single-pass yield greater than 95%. The generated byproduct, fluoroethane (R161), is an excellent refrigerant and can replace existing refrigerants such as difluorochloromethane (R22) in the future, possessing high industrial value. Detailed Implementation

[0020] The present invention will be further explained below with reference to the embodiments.

[0021] Unless otherwise specified, all raw materials used in this invention are commercially available; the room temperature / normal temperature is 25°C.

[0022] Examples 1-33 A supported catalyst and its preparation method A certain amount of superacid, active agent, and solvent were added to a 1000mL four-necked flask and stirred until dissolved, yielding a solution containing superacid and active agent. The solution containing superacid and active agent, along with 20g of support, was added to a 1000mL rotary evaporator and refluxed for 15 hours. The mixture was then filtered and dried under vacuum at 60℃ for 20 hours. After drying, the product was calcined in a muffle furnace at 500℃ for 5 hours to obtain the supported catalyst.

[0023] The supported catalyst prepared above was activated in a fixed-bed reactor. Specifically, 15 mL (approximately 14 g) of the supported catalyst was loaded into the fixed-bed reactor, and hydrogen fluoride was introduced at a flow rate of 50 mL / min for fluorination at 350 °C for 20 hours. After fluorination, nitrogen gas was introduced to cool the reactor down to 180 °C.

[0024] The fluorinated supported catalyst described above was used for the synthesis of difluoroacetyl fluoride. Specifically, in the fixed-bed reactor described above, hydrogen fluoride was vaporized at a flow rate of 160 mL / min, and 1,1,2,2-tetrafluoroethyl ether was vaporized at a flow rate of 0.4 g / min and then entered the reactor, maintaining a space velocity of 240 h⁻¹. -1 ~250h -1 After the reactor stabilizes (usually around 1 hour), samples are taken directly, and the product is analyzed directly. After peak area correction of the gas chromatogram, the corrected content is obtained, and then the conversion rate, selectivity, and single-pass yield are calculated. The conversion rate is calculated as follows: Conversion rate = 1 - Corrected 1,1,2,2-tetrafluoroethyl ether content; Selectivity is calculated as: Corrected difluoroacetyl fluoride content / Conversion rate / 67% (67% is the content of difluoroacetyl fluoride when theoretically completely converted); Single-pass yield is calculated as: Conversion rate * Selectivity.

[0025] In Examples 1-7 below, the active ingredient is 2g of molybdenum nitrate, the solvent is 600g of sulfolane, and the carrier is 20g of 250mg. 2 / g alumina, to verify the effect of different types of superacids and their dosages on the supported catalysts for the synthesis of difluoroacetyl fluoride (see Table 1 for details). Table 1

[0026] As can be seen from Table 1, when the supported catalyst is prepared without adding superacid to the active component, the conversion rate and single-pass yield of the resulting supported catalyst are extremely low when used for the synthesis of difluoroacetyl fluoride. However, when the mass of the superacid fluorosulfonic acid is 5g, the conversion rate and single-pass yield are the best.

[0027] In Examples 8-15 below, the superacid is 5g of fluorosulfonic acid, the solvent is 600g of sulfolane, and the carrier is 20g of 250m. 2 / g alumina, to verify the effect of supported catalysts prepared by different types of active additives and their dosages on the synthesis of difluoroacetyl fluoride (see Table 2 for details). Table 2

[0028] As can be seen from Table 2, when the active component is not added during the preparation of the supported catalyst, the conversion rate and single-pass yield of the resulting supported catalyst are significantly reduced when used for the synthesis of difluoroacetyl fluoride. However, when the mass of the active additive molybdenum nitrate is 2g, the conversion rate and single-pass yield are the best.

[0029] In Examples 16-24 below, the superacid was 5g of fluorosulfonic acid, the active agent was 2g of molybdenum nitrate, and the solvent was 600g of sulfolane. The effects of supported catalysts prepared with different types of supports and different surface areas on the synthesis of difluoroacetyl fluoride were verified (see Table 3 for details). Table 3

[0030] As shown in Table 3, when using alumina as the support in the preparation of the supported catalyst, the resulting supported catalyst exhibits significantly better conversion and single-pass yield in the synthesis of difluoroacetyl fluoride, and the support has a specific surface area of ​​250 m². 2 / g~600m 2 At / g, the conversion rate and single-pass yield are significantly improved.

[0031] In Examples 25-33 below, the superacid is 4g of fluorosulfonic acid, the active ingredient is 2g of molybdenum nitrate, and the carrier is 20g of 250m. 2 / g alumina, to verify the effect of supported catalysts prepared by different types of solvents and their amounts on the synthesis of difluoroacetyl fluoride (see Table 4 for details). Table 4

[0032] As can be seen from Table 4, when solvents such as carbon tetrachloride, chloroform, and sulfolane are used in the preparation of supported catalysts, the resulting supported catalysts have good conversion rates and single-pass yields when used for the synthesis of difluoroacetyl fluoride.

[0033] Examples 34-51 Application of a supported catalyst in the synthesis of difluoroacetyl fluoride Add 5g of fluorosulfonic acid, 2g of molybdenum nitrate, and 600g of sulfolane to a 1000mL four-necked flask, stir until dissolved, and obtain a solution containing fluorosulfonic acid and molybdenum nitrate. Then, add 20g of a sample with a specific surface area of ​​250m² to the solution containing fluorosulfonic acid and molybdenum nitrate. 2 / g of alumina was added to a 1000mL rotary evaporator and impregnated under reflux for 15 hours. The mixture was then filtered and dried under vacuum at 60℃ for 20 hours. After drying, the product was calcined in a muffle furnace at 500℃ for 5 hours to obtain 21.2g of supported catalyst.

[0034] The supported catalyst prepared above was activated in a fixed-bed reactor. Specifically, 14.3 g of the above supported catalyst (15 mL) was loaded into the fixed-bed reactor, and hydrogen fluoride was introduced at a flow rate of 50 mL / min for fluorination at a temperature of 350 °C for 20 hours. After fluorination, nitrogen gas was introduced to cool the reactor down to 180 °C.

[0035] The fluorinated supported catalyst described above was used for the synthesis of difluoroacetyl fluoride. Specifically, in the fixed-bed reactor described above, hydrogen fluoride and 1,1,2,2-tetrafluoroethyl ether were vaporized at a certain flow rate and then entered the reactor. After maintaining a certain space velocity and allowing the reactor to stabilize (usually about 1 hour), samples were directly taken, and the product was directly analyzed. After peak area correction of the gas chromatogram, the corrected content was obtained, and then the conversion, selectivity, and single-pass yield were calculated. The conversion rate was calculated as follows: Conversion rate = 1 - Corrected 1,1,2,2-tetrafluoroethyl ether content; Selectivity = Corrected difluoroacetyl fluoride content / Conversion rate / 67% (67% is the theoretical content of difluoroacetyl fluoride when completely converted); Single-pass yield = Conversion rate * Selectivity.

[0036] In Examples 34-39 below, the feed rate of 1,1,2,2-tetrafluoroethyl ether is 0.4 g / min, and the space velocity is controlled at 240-250 h⁻¹. -1 The reaction bed temperature was 180℃ to verify the effect of introducing hydrogen fluoride at different flow rates in the synthesis of difluoroacetyl fluoride (see Table 5 for details). Table 5

[0037] As shown in Table 5, the conversion rate and single-pass yield were highest when the flow rate of the protective gas hydrogen fluoride was 40 mL / min during the synthesis of difluoroacetyl fluoride. However, at this flow rate, the ethylene content in the product was high, and the cracking of fluoroethane was severe. On the other hand, when the flow rate of hydrogen fluoride was 160 mL / min, the conversion rate and single-pass yield were also very high, and the ethylene content in the product was low, which could avoid the cracking of fluoroethane. This shows that the presence of an appropriate amount of protective gas can prevent the byproduct fluoroethane from cracking into ethylene and hydrogen fluoride.

[0038] In Examples 34-39 below, the hydrogen fluoride feed rate was 160 mL / min and the reaction bed temperature was 180 °C to verify the effects of introducing different flow rates of 1,1,2,2-tetrafluoroethyl ethyl ether and different space velocities in the synthesis of difluoroacetyl fluoride (see Table 5 for details). Table 5

[0039] As shown in Table 5, during the synthesis of difluoroacetyl fluoride, the highest conversion rate and single-pass yield were achieved when the feed flow rate of 1,1,2,2-tetrafluoroethyl ether was 0.2 g / min. However, at this rate, the ethylene content was high, indicating that fluoroethane cracking occurred. Conversely, when the feed flow rate of 1,1,2,2-tetrafluoroethyl ether was 0.4 g / min, both the conversion rate and selectivity were high, while the ethylene content was low, preventing fluoroethane cracking. Therefore, the optimal feed rate was 0.4 g / min.

[0040] In Examples 34-39 below, the hydrogen fluoride feed rate was 160 mL / min and the 1,1,2,2-tetrafluoroethyl ether feed rate was 0.4 g / min, to verify the effect of different bed temperatures in the synthesis of difluoroacetyl fluoride (see Table 6 for details). Table 6

[0041] As can be seen from Table 6, during the synthesis of difluoroacetyl fluoride, the single-pass yield can be greater than 95% within the bed temperature range specified in this invention. Considering that high temperature will cause the cracking of fluoroethane, the optimal bed temperature is 180℃.

[0042] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the description of the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention.

[0043] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A supported catalyst, comprising a support and an active component, characterized in that, The active component includes a superacid and an active additive; in the supported catalyst, the loading of the superacid is 20wt% to 25wt%, and the loading of the active additive is 5wt% to 10wt%; the superacid is selected from at least one of fluoroboric acid, fluorosulfonic acid, fluoroantimonic acid, and carboraneic acid; the active additive is selected from at least one of molybdenum nitrate, technetium nitrate, ruthenium nitrate, rhodium nitrate, and chromium nitrate.

2. The supported catalyst according to claim 1, characterized in that, The carrier is selected from at least one of alumina, silica gel, and pumice.

3. The supported catalyst according to claim 2, characterized in that, The specific surface area of ​​the carrier is 50m². 2 / g~700m 2 / g, preferably 200m 2 / g~600m 2 / g.

4. The method for preparing the supported catalyst according to any one of claims 1-3, characterized in that, The preparation method includes: impregnating the carrier with a solution containing active components.

5. The preparation method according to claim 4, characterized in that, The solution containing active components includes a superacid and an active additive, wherein the mass ratio of the superacid to the active additive is (2-5):

1. And / or, the mass ratio of the active component to the carrier is (5-7):20; And / or, the solvent in the solution containing the active component is selected from at least one of carbon tetrachloride, chloroform, and sulfolane; the amount of the solvent is 30 to 100 times the mass of the active component.

6. The preparation method according to claim 4, characterized in that, The impregnation conditions include: impregnation time of 10 to 15 hours under reflux conditions; Preferably, the impregnation process further includes filtration, vacuum drying, and calcination; More preferably, the vacuum drying temperature is 50℃~60℃; the calcination conditions include: calcination temperature of 400℃~500℃ and calcination time of 4 hours~5 hours.

7. A method for synthesizing difluoroacetyl fluoride, characterized in that, The method comprises: in the presence of a protective gas, 1,1,2,2-tetrafluoroethyl ether is cracked to obtain difluoroacetyl fluoride under the action of a supported catalyst according to any one of claims 1-3 or a supported catalyst prepared by the preparation method according to any one of claims 4-6, wherein the protective gas is selected from hydrogen fluoride.

8. The synthesis method according to claim 7, characterized in that, The feed rate of the 1,1,2,2-tetrafluoroethyl ether is 0.2 g / min to 1.4 g / min, preferably 0.4 g / min to 0.8 g / min; And / or, the flow rate of the protective gas is 40 mL / min to 170 mL / min, preferably 120 mL / min to 160 mL / min; And / or, the pyrolysis conditions include: a temperature of 150°C to 300°C, preferably 150°C to 180°C, and a volume hourly space velocity of 120 h⁻¹. -1 ~900h -1 .

9. The synthesis method according to claim 7, characterized in that, The supported catalyst also includes a fluorination process; Preferably, the fluorination process includes: fluorinating the supported catalyst according to any one of claims 1-3 or the supported catalyst prepared by the preparation method according to any one of claims 4-6 in a fluorinating gas.

10. The synthesis method according to claim 7, characterized in that, The fluorinating gas is selected from at least one of hydrogen fluoride and chlorofluoromethane; the fluorination conditions include: a fluorination temperature of 200℃ to 400℃ and a fluorination time of 12 hours to 20 hours.

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