Highly selective catalyst for the preparation of heptafluoroisobutyryl fluoride, process for its preparation and use

Abstract

The application relates to the technical field of fluorinated chemicals, and specifically discloses a high-selectivity catalyst for preparing heptafluoroisobutyryl fluoride, a preparation method and application. The high-selectivity catalyst comprises a carrier and a metal active component loaded on the carrier; wherein the metal active component is selected from Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Y, Sc, Cr and Mo. The catalyst can efficiently catalyze the addition reaction of hexafluoropropylene and carbonyl fluoride under mild conditions, and then prepare heptafluoroisobutyryl fluoride, and can significantly inhibit the generation of by-product perfluoroheptanone, realize high-selectivity regulation, and control the proportion of by-products at a very low level. Meanwhile, the catalyst has strong stability, and can still maintain high-efficiency catalytic performance after being continuously produced for 500 hours. The catalyst and the method have good economy and industrial application prospect, and are suitable for large-scale continuous production.

Description

Technical Field

[0001] This application relates to the technical field of fluorochemicals, specifically to a highly selective catalyst for the preparation of heptafluoroisobutyryl fluoride, its preparation method, and its application. Background Technology

[0002] Perfluoroisobutyryl fluoride (also known as heptafluoroisobutyryl fluoride) is a high-value-added fluorine-containing fine chemical intermediate with wide and irreplaceable applications in electronic chemicals (such as high-purity cleaning agents and precision etching agents), fluorine-containing material monomers, pesticide intermediates, and the preparation of functional materials.

[0003] Currently, perfluoroisobutyryl fluoride is prepared by oxidative cracking, acyl fluoride addition, and electrolytic fluorination.

[0004] Oxidative cracking, as described in CN 109761795 A, CN 119039134 A, and CN 109651131 A, involves the cracking of hexafluoropropylene dimer (or trimer) with oxygen in the presence of a catalyst to produce perfluoroisobutyryl fluoride. Oxidative cracking allows for continuous production, but the yield of perfluoroisobutyryl fluoride is low, and the cracking process produces numerous byproducts, making product purification difficult.

[0005] Electrolytic fluorination is a common industrial preparation method, as shown in CN 111205197 A. It has low raw material costs, but requires the addition of a large amount of anhydrous hydrogen fluoride during the reaction process and produces a variety of product components, which increases the difficulty of product purification.

[0006] The acyl fluoride addition method synthesizes perfluoroisobutyryl fluoride by reacting carbonyl fluoride with hexafluoropropylene in the presence of a catalyst. The acyl fluoride addition method offers advantages such as high yield, continuous reaction, and high production efficiency.

[0007] CN 121005618 A provides a continuous production process for heptafluoroisobutyryl fluoride. The process uses carbonyl fluoride and hexafluoropropylene as gas-phase reaction feedstocks and synthesizes heptafluoroisobutyryl fluoride through a one-step continuous flow rapid reaction. The continuous production process is carried out in a tubular reactor, which is divided into a first preheating section, a second reaction section and a third reaction section from the inlet end to the outlet end. The reaction device is relatively complex.

[0008] CN 118056812 A discloses a method for preparing perfluoroisobutyryl fluoride, in which hexafluoropropylene and carbonyl fluoride are continuously fed into a primary reaction tube, and the reaction is carried out in the presence of an organic solvent, an organic base, and a fluorinated quaternary salt to obtain a perfluoroisobutyryl fluoride reaction mixture. After the reaction is completed, the organic base and fluorinated quaternary salt are difficult to recover in the complex system.

[0009] Carbonyl fluoride can undergo a condensation reaction with straight-chain olefins in the presence of fluoride anion catalysts to form acyl fluorides. These catalysts are typically selected from non-oxidizing fluoride salts, including fluorides of alkali metals, iron, cobalt, nickel, zinc, tin, and bismuth, as well as tetraalkylammonium fluoride and trialkylammonium fluoride. Existing research shows that in the presence of the aforementioned fluoride salts or organic amine catalysts, the carbon-carbon double bond of hexafluoropropylene breaks, and simultaneously, the F-C bond of the carbonyl fluoride partially or completely breaks. The resulting acyl fluoride radical combines with the hexafluoropropylene radical to form perfluoroisobutyryl fluoride (i.e., heptafluoroisobutyryl fluoride). However, existing catalyst systems generally suffer from high cost, difficulty in balancing reactivity and selectivity, and short catalyst lifespan, which restricts their industrial application.

[0010] Therefore, developing a highly selective, highly stable catalyst suitable for continuous production of heptafluoroisobutyryl fluoride and its preparation process is of great significance for reducing production costs, improving product quality, and promoting the upgrading of downstream industries. Summary of the Invention

[0011] This application provides a highly selective catalyst for the preparation of heptafluoroisobutyryl fluoride, a preparation method, and its application. Using hexafluoropropylene and carbonyl fluoride as raw materials, the addition reaction catalyzed by this catalyst can yield heptafluoroisobutyryl fluoride with high selectivity and significantly reduce the byproduct perfluoroheptanone.

[0012] This application involves the following: 1. A highly selective catalyst for the preparation of heptafluoroisobutyryl fluoride, comprising a support and a metal active component supported on the support; The active metal component is selected from any one or two or more of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Y, Sc, Cr and Mo.

[0013] 2. The highly selective catalyst according to item 1, wherein the loading of the metal active component on the support is 1~30 wt%; preferably 8~30 wt%.

[0014] 3. The highly selective catalyst according to item 1 or 2, wherein the support is modified and / or unmodified activated carbon; The modified activated carbon includes nitrogen-doped activated carbon and / or boron-doped activated carbon; Preferably, the nitrogen doping amount in the modified activated carbon is 0.5~10 wt%; and / or The modified activated carbon contains 0.1 to 5 wt% boron.

[0015] 4. The highly selective catalyst according to item 3, wherein the method for preparing the modified activated carbon includes: acid washing, high-temperature solid-phase doping, and pre-fluorination of unmodified activated carbon; Preferably, the pickling treatment uses hydrochloric acid and / or nitric acid, and preferably the mass percentage of the hydrochloric acid and / or nitric acid in the solution is 1-20 wt%; and / or The pickling temperature is 60~90℃; and / or The pickling process takes 4-8 hours. Preferably, the temperature of the high-temperature solid-phase doping treatment is 500~1200℃; and / or The high-temperature solid-phase doping treatment time is 0.5~5h; and / or During the high-temperature solid-phase doping treatment, a nitrogen precursor is added, preferably selected from any one or more of urea, melamine, or dicyandiamide; During the high-temperature solid-phase doping treatment, a boron precursor is added, preferably selected from any one or more of boric acid, amorphous boron, or boron carbide; Preferably, the prefluorination treatment is carried out in the presence of hydrogen fluoride, more preferably in the presence of a mixture of hydrogen fluoride and an inert gas, and more preferably, the hydrogen fluoride in the mixture is 1-20 vol.%, preferably 5-15 vol.%; and / or The pre-fluorination treatment is performed at a temperature of 200~400℃; and / or The pre-fluorination treatment takes 2 to 6 hours.

[0016] 5. A method for preparing a highly selective catalyst for preparing heptafluoroisobutyryl fluoride according to any one of items 1 to 4, comprising the following steps: The carrier is immersed in a solution of a metal active component containing a metal active component, thereby loading the metal active component onto the carrier; It is then activated by heating in an inert gas environment.

[0017] 6. The preparation method according to item 5, wherein the volume ratio of the metal active component solution to the carrier is (1~2):1; and / or The soaking time is 15-36 hours.

[0018] 7. The preparation method according to item 5 or 6, wherein the activation temperature is 100~300℃; and / or The activation time is 1~24h.

[0019] 8. A method for preparing heptafluoroisobutyryl fluoride, comprising: carrying out an addition reaction of hexafluoropropylene and carbonyl fluoride under the catalysis of any one of the catalysts in items 1 to 4 and / or a catalyst prepared by any one of the preparation methods in items 5 to 7.

[0020] 9. The method according to item 8, wherein the feed volume ratio of the carbonyl fluoride and hexafluoropropylene is (1~10):1; and / or In the addition reaction, the feed volume hourly space velocity (VHSV) for hexafluoropropylene and carbonyl fluoride is 36–360 h⁻¹. -1 .

[0021] 10. The method according to item 8 or 9, wherein the temperature of the addition reaction is 50~200°C; preferably 130~150°C.

[0022] Beneficial effects: 1. The catalyst provided in this application exhibits excellent selectivity when used to catalyze the addition reaction of hexafluoropropylene with carbonyl fluoride to prepare heptafluoroisobutyryl fluoride, significantly improving the yield of the target product while effectively suppressing the formation of the byproduct perfluoroheptanone, thereby simplifying the subsequent separation and purification process. Furthermore, the catalyst demonstrates good stability and a long service life during continuous reactions, reducing the frequency of catalyst replacement and production costs.

[0023] 2. The catalyst of this application has a simple preparation process, is easy to operate, has low cost and is suitable for large-scale industrial production; at the same time, the catalyst is suitable for fixed-bed reactors, which can realize continuous production and significantly improve production efficiency.

[0024] 3. The heptafluoroisobutyryl fluoride prepared by the method of this application, after further purification, can achieve a purity of over 99.99%, which can meet the demand for high-purity raw materials in the fields of high-end fluorine-containing functional chemicals and electronic specialty gases. Attached Figure Description

[0025] Figure 1 The gas chromatography analysis results of Example 4 are applied.

[0026] Figure 2 Gas chromatographic analysis results of Comparative Example 3.

[0027] Figure 3 Gas chromatogram of purified heptafluoroisobutyryl fluoride from Application Example 35. Detailed Implementation

[0028] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in their functions.

[0029] As used throughout the specification and claims, the terms "comprising" or "including" are open-ended and should be interpreted as "comprising but not limited to". The subsequent descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0030] It should be understood that the embodiments of this application described herein include embodiments that are "composed of" and / or "substantially composed of". References to values ​​or parameters of "about" herein include (and describe) variations of that value or parameter itself. For example, a reference to "about X" includes a description of "X".

[0031] As used herein, references to “not” values ​​or parameters generally refer to and describe “except” values ​​or parameters. For example, “The method is not used to treat type X cancer” means that the method is used to treat cancers other than type X.

[0032] As used in this article, the term “approximately XY” has the same meaning as “approximately X to approximately Y”.

[0033] As used herein and in the appended claims, the singular forms “a / an” and “the” include the plural objects unless the context clearly indicates otherwise. It should also be noted that claims may be drafted to exclude any optional elements. Therefore, this statement is intended as a preliminary basis for the use of exclusive terms such as “only” or “merely” in conjunction with the description of the elements of the claim, or for the use of the limitation of “no”.

[0034] As used herein, the term "and / or" in words such as "A and / or B" is intended to include both A and B; A or B; A (alone); and B (alone). Similarly, as used herein, the term "and / or" in words such as "A, B and / or C" is intended to include each of the following embodiments: A, B and C; A, B or C; A or C; A or B; B or C; A and C; A and B; B and C; A (alone); B (alone); and C (alone).

[0035] This application provides a highly selective catalyst for the preparation of heptafluoroisobutyryl fluoride, comprising a support and a metal active component supported on the support; The active metal component is selected from any one or two or more of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Y, Sc, Cr and Mo.

[0036] In some embodiments, the metal active component is initially mixed with the support as a metal fluoride, and the metal active component is further loaded onto the support. In some embodiments, the metal fluoride is selected from any one or more combinations of NaF, KF, RbF, CsF, MgF2, CaF2, SrF2, BaF2, LaF3, ScF3, YF3, CrF3, and MoF3.

[0037] In some embodiments, the loading amount of the metal active component on the carrier is any range within the range of 1~30wt%, 2~30wt%, 5~30wt%, 7~30wt%, 8~30wt%, 9~30wt%, 10~30wt%, or 1~30wt%; for example, it can be any percentage or any value within the range of 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, 25wt%, 26wt%, 27wt%, 228wt%, 9wt%, 30wt%, or 1~30wt%; in some preferred embodiments, it is 8~30wt%. The applicant discovered that the loading of the metal active component on the support has a certain impact on the reaction results. When the proportion of the active component in the catalyst is not less than 5 wt%, the selectivity of the byproduct perfluoroheptanone will decrease from 21.7% to 13.8%, or even as low as 12.6%, 10.1%, or even lower, such as 9%; while the selectivity of the target product heptafluoroisostyryl fluoride is significantly improved, for example, at least 86.2%, or even as high as 89.9%, or even higher, such as 90% or 91%.

[0038] In some embodiments, the support is modified activated carbon. The activated carbon treatment will improve the loading performance of the support to a certain extent, for example, by increasing the number and diversity of active sites on the support; thus, making the loading performance of the support superior.

[0039] In some embodiments, the modified activated carbon includes nitrogen-doped activated carbon. In some embodiments, the modified activated carbon includes boron-doped activated carbon. In some embodiments, the modified activated carbon includes both nitrogen-doped and boron-doped activated carbon. The applicant has found that nitrogen doping alone without boron doping, or boron doping alone without nitrogen doping, both affect the catalytic performance of the catalyst, resulting in a certain degree of reduction in the selectivity of the target product, for example, a reduction of about 8% or about 14%.

[0040] In some embodiments, the amount of nitrogen doped in the modified activated carbon is 0.5 to 10 wt%; for example, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt% or any percentage or range of any value within the range of 0.5 to 10 wt%.

[0041] In some embodiments, the modified activated carbon contains boron doping in an amount of 0.1 to 5 wt%; for example, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, or any percentage or range of any value within the range of 0.1 to 5 wt%.

[0042] In some embodiments, the method for preparing modified activated carbon includes: acid washing of unmodified activated carbon. In some embodiments, the method for preparing modified activated carbon includes: high-temperature solid-phase doping of unmodified activated carbon. In some embodiments, the method for preparing modified activated carbon includes: pre-fluorination of unmodified activated carbon. In some embodiments, the method for preparing modified activated carbon includes: acid washing and high-temperature solid-phase doping of unmodified activated carbon. In some embodiments, the method for preparing modified activated carbon includes: acid washing, high-temperature solid-phase doping, and pre-fluorination of unmodified activated carbon.

[0043] As is well known to those skilled in the art, the pickling treatment in this application can be any acid treatment, such as organic acids (e.g., oxalic acid, citric acid, acetic acid, lactic acid, etc. or any combination thereof) or inorganic acids (e.g., hydrochloric acid, sulfuric acid or nitric acid, phosphoric acid, etc. or any combination thereof). In some embodiments, the pickling treatment uses hydrochloric acid and / or nitric acid. In some embodiments, the hydrochloric acid and / or nitric acid in the solution has a mass percentage of 1 to 20 wt%; for example, it can be any percentage or any range of values ​​within the range of 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, or 1 to 20 wt%. In some embodiments, the pickling temperature is 60~90℃; specifically, it can be any temperature or any value within the range of 60℃, 65℃, 68℃, 70℃, 72℃, 73℃, 75℃, 76℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 88℃, 90℃, or 60~90℃. In some embodiments, the pickling time is 4~8 hours; specifically, it can be any time or any value within the range of 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 7 hours, 7.5 hours, 8 hours, or 4~8 hours.

[0044] As is well known to those skilled in the art, the high-temperature solid-phase doping in this application can be performed using methods conventionally used in the art. For example, in some embodiments, the temperature of the high-temperature solid-phase doping treatment is 500~1200℃; specifically, it can be any temperature or any value within the range of 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃, 1150℃, 1200℃, or any temperature or any value within the range of 500~1200℃. In some embodiments, the time of the high-temperature solid-phase doping treatment is 0.5~5h; specifically, it can be any time or any value within the range of 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, or any time or any value within the range of 0.5~5h.

[0045] In some embodiments, a nitrogen precursor is added during the high-temperature solid-phase doping treatment. This nitrogen precursor can be selected from any conventional or available nitrogen precursor well known to those skilled in the art. In some embodiments, the nitrogen precursor is selected from any one or more of urea, melamine, or dicyandiamide. In some embodiments, the nitrogen precursor is urea.

[0046] In some embodiments, a boron precursor is added during the high-temperature solid-state doping treatment. This boron precursor can be selected from any conventional or available boron precursor well known to those skilled in the art. In some embodiments, the boron precursor is selected from one or more of boric acid, amorphous boron, or boron carbide. In some embodiments, the boron precursor is boric acid.

[0047] In some embodiments, the prefluorination treatment is carried out in the presence of hydrogen fluoride. In some embodiments, it is carried out in the presence of a mixture of hydrogen fluoride and an inert gas. In some embodiments, the hydrogen fluoride in the mixture is 1-20 vol.%, 5-15 vol.%; for example, 1 vol.%, 2 vol.%, 3 vol.%, 5 vol.%, 7 vol.%, 8 vol.%, 10 vol.%, 12 vol.%, 15 vol.%, 18 vol.%, 20 vol.%, or any percentage within the range of 1-20 vol.%, or any range of any values.

[0048] In some embodiments, the temperature of the pre-fluorination treatment is 200~400°C; for example, it can be any temperature or any range between 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, or 200~400°C.

[0049] In some implementations, the pre-fluorination treatment time is 2 to 6 hours; for example, it can be any time or any value within the range of 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, or 2 to 6 hours.

[0050] This application also provides a method for preparing the above-mentioned highly selective catalyst for preparing heptafluoroisobutyryl fluoride, which includes the following steps: The carrier is immersed in a solution of a metal active component containing a metal active component, thereby loading the metal active component onto the carrier; It is then activated by heating in an inert gas environment.

[0051] In some embodiments, the volume ratio of the metal active component solution to the carrier is (1~2):1; for example, it can be any ratio or any range of values ​​within the range of 1:1, 1.5:1, 2:1 or (1~2):1.

[0052] In some implementations, the immersion time is 15 to 36 hours; for example, it can be any time or any value within the range of 15 hours, 16 hours, 18 hours, 20 hours, 22 hours, 25 hours, 27 hours, 30 hours, 33 hours, 35 hours, 36 hours, or 15 to 36 hours.

[0053] In some embodiments, the activation temperature is 100~300℃; for example, it can be any temperature or any range of values ​​within the range of 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃, 300℃, or 100~300℃.

[0054] In some embodiments, the activation time is 1 to 24 hours; specifically, it can be any time or any value within the range of 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 6 hours, 7 hours, 7.5 hours, 8 hours, 9 hours, 10 hours, 11 hours, 11.5 hours, 12 hours, 12.5 hours, 13 hours, 13.5 hours, 14 hours, 15 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, or any time range between 1 and 24 hours. During activation, to achieve the activation objective, the activation time can be extended while appropriately lowering the temperature; or the activation objective can be achieved in a shorter time at an appropriately higher temperature. Therefore, the activation time and temperature in this application are not limited to the above ranges.

[0055] This application provides a method for preparing heptafluoroisobutyryl fluoride, comprising: carrying out an addition reaction of hexafluoropropylene and carbonyl fluoride under the catalysis of the above-described catalyst and / or a catalyst prepared by the above-described preparation method.

[0056] In some embodiments, the feed volume ratio of fluorocarbonyl fluoride to hexafluoropropylene is (1~10):1; specifically, it can be 1:1, 1.5:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, or any ratio or range within the above ranges. In some embodiments, in the addition reaction, the feed volume hourly space velocity of hexafluoropropylene and fluorocarbonyl fluoride is 36~360 h⁻¹. -1 For example, it could be 36 hours. -1 40h -1 50h -1 60h -1 72h -1 80h -1 90h -1100h -1 110h -1 120h -1 130h -1 140h -1 150h -1 160h -1 170h -1 180h -1 190h -1 200h -1 210h -1 220h -1 230h -1 240h -1 250h -1 260h -1 270h -1 280h -1 290h -1 300h -1 310h -1 320h -1 330h -1 340h -1 350h -1 360h -1 Or any airspeed or any airspeed range within the above range.

[0057] In this application, the addition reaction under the action of the catalyst is rapid, and the reaction generally occurs rapidly after reaching the reaction temperature (e.g., 50~200℃; e.g., 130~150℃); for example, the reaction occurs within 5~10 seconds; however, when samples are taken for detection at reaction times such as at least 1 min, 2 min, 5 min, 10 min, 30 min, 40 min, 50 min, 60 min, 1.5 h, and 2 h, the reaction results are already significantly excellent, with the selectivity of the target product reaching over 99%. In some embodiments, the temperature of the addition reaction is any temperature range within the range of 50~200℃, 100~200℃, 130~200℃, 140~200℃, 150~200℃, 50~180℃, 100~180℃, 130~180℃, 140~180℃, 150~180℃, 50~150℃, 100~150℃, 130~150℃, 140~150℃, or 50~200℃; for example, it can specifically be any temperature within the range of 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, or 50~200℃. This application found that when the reaction temperature is above 120℃, the conversion rate of hexafluoropropylene is significantly improved, reaching over 99%; the selectivity of the target product heptafluoroisostyryl fluoride is significantly improved, even reaching 99%.

[0058] Example Specific embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While specific embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0059] Example 1 The highly selective catalyst for preparing heptafluoroisobutyryl fluoride and its preparation method are as follows: S1: Acid washing pretreatment of activated carbon support Weigh 100 g of activated carbon and place it in a 1000 mL three-necked flask. Add 600 mL of 10% hydrochloric acid solution (solid-liquid ratio 1:6). Stir in an oil bath at 80 °C for 6 h. After treatment, allow to cool naturally to room temperature, filter, and wash repeatedly with deionized water until the pH of the washing solution reaches 7. Dry at 110 °C for 12 h to obtain the acid-washed and purified activated carbon support, denoted as AC-H support.

[0060] S2: High-temperature solid-phase nitrogen and boron co-doping modification Weigh 20 g of the above AC-H support and place it in a ball mill jar with 4 g of urea and 1 g of boric acid. Mechanically mix at 300 r / min for 40 min to ensure uniform powder mixing. Transfer the mixture to a corundum boat and place it in a tube furnace. Under a nitrogen atmosphere (nitrogen flow rate 100 mL / min), the temperature is programmed to rise to 900 °C at a rate of 8 °C / min and held at this temperature for 2 h to carry out a high-temperature solid-phase doping reaction. After the reaction, allow it to cool naturally to room temperature, remove the product, wash it three times with deionized water, and dry it at 110 °C for 6 h to obtain the nitrogen- and boron co-doped modified activated carbon support, denoted as AC-NB support.

[0061] S3: Pre-fluorination treatment 15 g of AC-NB support was weighed and placed in a fixed-bed reactor. Under nitrogen purging (flow rate 50 mL / min), the temperature was increased to 300 °C at a rate of 5 °C / min, and preheated at this temperature for 30 min. Then, the reactor was switched to a fluorinated gas mixture, with a volume fraction of 10% HF / N2 mixed gas introduced at a flow rate controlled at 30 mL / min, and treated at 300 °C for 4 h. After treatment, the reactor was switched back to nitrogen purging for 1 h to replace the residual fluorinated gas, and then allowed to cool naturally to room temperature to obtain the pre-fluorinated modified composite support, denoted as AC-NB-F support.

[0062] S4: Impregnation loading of active components A certain amount of NaF was dissolved in deionized water to prepare an impregnation solution. The modified activated carbon support (AC-NB-F support) obtained in S3 was immersed in the above sodium fluoride aqueous solution, controlling the loading of sodium metal component to be 10 wt% of the total mass of the final catalyst, and the volume ratio of support to impregnation solution to be 1:2. The mixture was allowed to stand at room temperature for 24 h to allow Na ions to be fully adsorbed and diffused into the pores of the support. After impregnation, the mixture was placed in an oven and dried at 100 ℃ for 12 h to remove moisture. The dried solid was then transferred to a tube furnace and activated at 300 ℃ for 10 h under a nitrogen atmosphere (flow rate 50~100 mL / min), and then naturally cooled to room temperature to obtain a 10 wt% NaF / AC-NB-F supported catalyst.

[0063] Example 2 The only difference between Example 2 and Example 1 is that sodium fluoride is replaced with potassium fluoride, and the mass percentage of the alkali metal potassium active component in the catalyst is adjusted to 10 wt%. All other conditions are the same, and a catalyst of 10 wt% KF / AC-NB-F is prepared.

[0064] Example 3 The only difference between Example 2 and Example 1 is that sodium fluoride is replaced with rubidium fluoride, so that the alkali metal rubidium active component accounts for 10 wt% of the catalyst. All other conditions are the same, and a catalyst of 10 wt% RbF / AC-NB-F is prepared.

[0065] Example 4 The only difference between Example 4 and Example 1 is that sodium fluoride is replaced with cesium fluoride, so that the alkali metal cesium active component accounts for 10 wt% of the catalyst. All other conditions are the same, and a catalyst of 10 wt% CsF / AC-NB-F is prepared.

[0066] The specific steps are as follows: S1, S2, and S3 are the same as in Example 4. Specifically, S4 involves dissolving a certain amount of CsF in deionized water to prepare an impregnation solution. The modified activated carbon support (AC-NB-F support) obtained in S3 is then impregnated in the aforementioned sodium cesium chloride aqueous solution, controlling the loading of the cesium metal component to be 10 wt% of the total mass of the final catalyst, with a volume ratio of support to impregnation solution of 1:2. The mixture is allowed to stand at room temperature for 24 h to allow Cs ions to be fully adsorbed and diffused into the pores of the support. After impregnation, the mixture is placed in an oven and dried at 100 °C for 12 h to remove moisture. The dried solid is then transferred to a tube furnace and activated at 300 °C for 10 h under a nitrogen atmosphere (flow rate 50~100 mL / min), followed by natural cooling to room temperature to obtain a 10 wt% CsF / AC-NB-F supported catalyst.

[0067] Example 5 The only difference between Example 5 and Example 1 is that sodium fluoride is replaced with magnesium fluoride, so that the active component magnesium accounts for 10 wt% of the catalyst. All other conditions are the same, and a catalyst of 10 wt% MgF2 / AC-NB-F is prepared.

[0068] Example 6 The only difference between Example 6 and Example 1 is that sodium fluoride is replaced with calcium fluoride, so that the active component calcium accounts for 10 wt% of the catalyst. All other conditions are the same, and a catalyst of 10 wt% CaF2 / AC-NB-F is prepared.

[0069] Example 7 The only difference between Example 7 and Example 1 is that sodium fluoride is replaced with strontium fluoride, so that the active component strontium accounts for 10 wt% of the catalyst. All other conditions are the same, and a catalyst of 10 wt% SrF2 / AC-NB-F is prepared.

[0070] Example 8 The only difference between Example 8 and Example 1 is that sodium fluoride is replaced with barium fluoride, so that the active component barium accounts for 10 wt% of the catalyst. All other conditions are the same, and a catalyst of 10 wt% BaF2 / AC-NB-F is prepared.

[0071] Example 9 The only difference between Example 9 and Example 1 is that sodium fluoride is replaced with lanthanum fluoride, so that the active component lanthanum accounts for 10 wt% of the catalyst. All other conditions are the same, and a catalyst of 10 wt% LaF3 / AC-NB-F is prepared.

[0072] Example 10 The only difference between Example 10 and Example 1 is that sodium fluoride is replaced with scandium fluoride, so that the active component scandium accounts for 10 wt% of the catalyst. All other conditions are the same, and a catalyst of 10 wt% ScF3 / AC-NB-F is prepared.

[0073] Example 11 The only difference between Example 11 and Example 1 is that sodium fluoride is replaced with yttrium fluoride, so that the active component yttrium accounts for 10 wt% of the catalyst. All other conditions are the same, and a catalyst of 10 wt% YF3 / AC-NB-F is prepared.

[0074] Example 12 The only difference between Example 12 and Example 1 is that sodium fluoride is replaced with chromium fluoride, so that the active component chromium accounts for 10 wt% of the catalyst. All other conditions are the same, and a catalyst of 10 wt% CrF3 / AC-NB-F is prepared.

[0075] Example 13 The only difference between Example 13 and Example 1 is that sodium fluoride is replaced with molybdenum fluoride, so that the active component molybdenum accounts for 10 wt% of the catalyst. All other conditions are the same, and a catalyst of 10 wt% MoF3 / AC-NB-F is prepared.

[0076] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that the mass percentage of the alkali metal sodium active component is 0 wt%.

[0077] Specifically, the preparation method of the catalyst in this comparative example is as follows: S1: Acid washing pretreatment of activated carbon support Weigh 100 g of activated carbon and place it in a 1000 mL three-necked flask. Add 600 mL of 10% hydrochloric acid solution (solid-liquid ratio 1:6). Stir in an oil bath at 80 °C for 6 h. After treatment, allow to cool naturally to room temperature, filter, and wash repeatedly with deionized water until the pH of the washing solution reaches 7. Dry at 110 °C for 12 h to obtain the acid-washed and purified activated carbon support, denoted as AC-H support.

[0078] S2: High-temperature solid-phase nitrogen and boron co-doping modification Weigh 20 g of the above AC-H support and place it in a ball mill jar with 4 g of urea and 1 g of boric acid. Mechanically mix at 300 r / min for 40 min to ensure uniform powder mixing. Transfer the mixture to a corundum boat and place it in a tube furnace. Under a nitrogen atmosphere (nitrogen flow rate 100 mL / min), the temperature is programmed to rise to 900 °C at a rate of 8 °C / min and held at this temperature for 2 h to carry out a high-temperature solid-phase doping reaction. After the reaction, allow it to cool naturally to room temperature, remove the product, wash it three times with deionized water, and dry it at 110 °C for 6 h to obtain the nitrogen- and boron co-doped modified activated carbon support, denoted as AC-NB support.

[0079] S3: Pre-fluorination treatment 15 g of AC-NB support was weighed and placed in a fixed-bed reactor. Under nitrogen purging (flow rate 50 mL / min), the temperature was increased to 300 °C at a rate of 5 °C / min, and preheated at this temperature for 30 min. Then, the reactor was switched to a fluorinated gas mixture, with a volume fraction of 10% HF / N2 mixed gas introduced at a flow rate controlled at 30 mL / min, and treated at 300 °C for 4 h. After treatment, the reactor was switched back to nitrogen purging for 1 h to replace the residual fluorinated gas, and then allowed to cool naturally to room temperature to obtain the pre-fluorinated modified composite support, denoted as AC-NB-F support, which is the catalyst in this comparative example.

[0080] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that the support component has a mass ratio of 0 wt%, that is, only the same mass of sodium fluoride as the 10 wt% NaF / AC-NB-F supported catalyst in Example 1 is used.

[0081] Comparative Example 3 The only difference between Comparative Example 3 and Example 4 is that the original unmodified activated carbon was used as the catalyst support, while the other conditions were the same, and a catalyst of 10 wt% CsF / AC was prepared.

[0082] Specifically, the preparation method of the catalyst in this comparative example is as follows: A certain amount of CsF was dissolved in deionized water to prepare an impregnation solution. The unmodified activated carbon was then impregnated in the aforementioned cesium fluoride aqueous solution, with the cesium metal loading controlled to be 10 wt% of the total catalyst mass, and the volume ratio of support to impregnation solution being 1:2. The mixture was allowed to stand at room temperature for 24 h to allow Cs ions to be fully adsorbed and diffused into the pores of the support. After impregnation, the mixture was placed in an oven and dried at 100 °C for 12 h to remove moisture. The dried solid was then transferred to a tube furnace and activated at 300 °C for 10 h under a nitrogen atmosphere (flow rate 50–100 mL / min), followed by natural cooling to room temperature to obtain a 10 wt% CsF / C supported catalyst.

[0083] Application examples Application Example 1 The catalyst (10 wt% NaF / AC-NB-F) prepared in Example 1 was used as the evaluation object, and its performance was evaluated in a fixed-bed reactor. The specific operating steps are as follows: The activated catalyst was loaded into the isothermal zone of the fixed-bed reactor at a loading volume of 10 mL. Inert steel wire ball packing was used for support at both ends of the bed. After loading, the system was checked for airtightness under a nitrogen atmosphere. Once no leaks were confirmed, the system was switched to the reactant gas. The feed volume ratio of carbonyl fluoride and hexafluoropropylene was controlled at 3:1 (carbonyl fluoride: hexafluoropropylene), and the flow rate was precisely controlled using a mass flow meter. The fixed-bed reactor temperature was set to 120 °C, the reaction pressure to atmospheric pressure, and the space velocity to 360 h⁻¹. -1 Sampling and analysis were initiated after the reaction had been running stably for 2 hours. The reaction tail gas was treated with alkaline solution before being discharged. The composition of the reaction products was analyzed online or offline using gas chromatography (GC), and the conversion rate of hexafluoropropylene, the selectivity of heptafluoroisobutyryl fluoride, and the selectivity of the byproduct perfluoroheptanone were calculated.

[0084] The only difference between Application Example 2-15 and Application Example 1 is that the catalysts prepared by different examples or comparative examples were selected for the reaction, as shown in Table 1.

[0085] Table 1. Effect of different active components on the addition reaction of hexafluoropropylene

[0086] Table 1 shows that during the screening of catalyst active components, significant differences were found in the catalytic performance of different alkali metals for the addition reaction of hexafluoropropylene and carbonyl fluoride. Experimental results indicate that when cesium (Cs) was used as the active component, the catalyst exhibited superior catalytic activity, achieving an optimal conversion rate of 99.7%, and the selectivity for the target product, heptafluoroisobutyryl fluoride, reached 89.9% (gas chromatographic analysis results are shown in Table 1). Figure 1Combined with the gas chromatography analysis results of Comparative Example 3 (e.g.) Figure 2 As shown in the figure, the modification method of activated carbon has a significant impact on the catalytic performance and product selectivity of the catalyst. The catalyst prepared by the modification method of the present invention can effectively suppress the formation of the byproduct perfluoroheptanone, and its selectivity is significantly reduced from 27.6% in Comparative Example 3 to 13.9%, indicating that the activated carbon modification method used in the present invention significantly suppresses the occurrence of side reactions and greatly improves the selectivity of the target product.

[0087] Examples 14-17 The difference between Example 14 and Example 4 is that the alkali metal cesium active component accounts for 1 wt% of the catalyst, while the other conditions are the same, and a catalyst of 1 wt% CsF / AC-NB-F is prepared.

[0088] The difference between Example 15 and Example 4 is that the alkali metal cesium active component accounts for 5 wt% of the catalyst, while the other conditions are the same, and a catalyst of 5 wt% CsF / AC-NB-F is prepared.

[0089] The difference between Example 16 and Example 4 is that the alkali metal cesium active component accounts for 15 wt% of the catalyst, while the other conditions are the same, and a catalyst of 15 wt% CsF / AC-NB-F is prepared.

[0090] The difference between Example 17 and Example 4 is that the alkali metal cesium active component accounts for 30 wt% of the catalyst, while the other conditions are the same, and a catalyst of 30 wt% CsF / AC-NB-F is prepared.

[0091] The only difference between Application Examples 14-17 and Application Example 1 is that the catalysts prepared in different examples were selected for the reaction, as detailed in Table 2.

[0092] Table 2. Effects of different active components on the addition reaction of hexafluoropropylene

[0093] Comparative Example 4 The only difference between Comparative Example 4 and Example 4 is that nitrogen was not doped during the preparation of the catalyst; otherwise, they are the same as in Example 4.

[0094] S1: Acid washing pretreatment of activated carbon carrier, the specific steps are the same as in Example 4.

[0095] S2: High-temperature solid-phase boron doping modification Weigh 20 g of the above AC-H support and place it in a ball mill jar with 1 g of boric acid. Mix mechanically at 300 r / min for 40 min until the powder is homogeneous. Transfer the mixture to a corundum boat and place it in a tube furnace. Under a nitrogen atmosphere (nitrogen flow rate 100 mL / min), the temperature is programmed to rise to 900 ℃ at a rate of 8 ℃ / min and held at this temperature for 2 h to carry out a high-temperature solid-phase doping reaction. After the reaction, allow it to cool naturally to room temperature, remove the product, wash it three times with deionized water, and dry it at 110 ℃ for 6 h to obtain the boron-doped modified activated carbon support, denoted as AC-B support.

[0096] The specific steps for S3 and S4 are the same as in Example 4.

[0097] Comparative Example 5 The only difference between Comparative Example 5 and Example 4 is that boron is not doped during the preparation of the catalyst; otherwise, they are the same as in Example 4.

[0098] S1: Acid washing pretreatment of activated carbon carrier, the specific steps are the same as in Example 4.

[0099] S2: High-temperature solid-phase nitrogen doping modification Weigh 20 g of the AC-H support and place it in a ball mill jar with 4 g of urea. Mix mechanically at 300 r / min for 40 min until the powder is homogeneous. Transfer the mixture to a corundum boat and place it in a tube furnace. Under a nitrogen atmosphere (nitrogen flow rate 100 mL / min), the temperature is programmed to rise to 900 °C at a rate of 8 °C / min and held at this temperature for 2 h to carry out a high-temperature solid-phase doping reaction. After the reaction, allow it to cool naturally to room temperature, remove the product, wash it three times with deionized water, and dry it at 110 °C for 6 h to obtain the boron-doped modified activated carbon support, denoted as AC-N support.

[0100] The specific steps for S3 and S4 are the same as in Example 4.

[0101] The only difference between Application Examples 18-19 and Application Example 1 is that the catalysts prepared in different examples were selected for the reaction, as detailed in Table 3.

[0102] Table 3. Effects of different active components on the addition reaction of hexafluoropropylene

[0103] Application Examples 20-24 The only difference between Application Examples 20-24 and Application Example 4 is that the reaction temperature of the fixed bed is set differently during the reaction, as detailed in Table 4.

[0104] Table 4 Effect of different temperatures on the addition reaction of hexafluoropropylene

[0105] As shown in Table 4, the reaction temperature has a significant impact on the addition reaction of hexafluoropropylene. With increasing reaction temperature, the conversion rate of hexafluoropropylene gradually increases, while the selectivity of the target product, heptafluoroisobutyryl fluoride, increases significantly. When the reaction temperature reaches 140℃, the conversion rate of hexafluoropropylene reaches over 99.9%, the selectivity of heptafluoroisobutyryl fluoride is as high as 99.2%, while the selectivity of the byproduct perfluoroheptanone is only 0.8%. Further increasing the temperature to 150℃ does not significantly change the conversion rate of hexafluoropropylene or the selectivity of heptafluoroisobutyryl fluoride. Considering both reaction efficiency and energy consumption, 140℃ is selected as the optimal reaction temperature for this system.

[0106] Application Examples 25-29 The only difference between Application Examples 25-29 and Application Example 23 is that the feed space velocity is set differently during the reaction, as detailed in Table 5.

[0107] Table 5. Effect of different feed space velocities on the addition reaction of hexafluoropropylene

[0108] As shown in Table 5, the conversion rate of hexafluoropropylene remained stable at 99.9% within the investigated space velocity range, indicating that the catalyst exhibits excellent catalytic activity over a wide space velocity range. With decreasing space velocity, the selectivity for the target product, heptafluoroisobutyryl fluoride, showed a slight increasing trend, while the selectivity for the byproduct, perfluoroheptanone, decreased accordingly. When the space velocity decreased from 360 h⁻¹... -1 Reduced to 72h -1 At that time, the selectivity of heptafluoroisobutyryl fluoride increased from 99.2% to 99.8%, while the selectivity of perfluoroheptanone decreased from 0.8% to 0.2%. However, considering overall production efficiency, an air velocity of 72-180 h⁻¹ was selected. -1 It can achieve high processing power while maintaining high selectivity.

[0109] Application Examples 30-34 The only difference between Application Examples 30-34 and Application Example 23 is that the feed ratio of carbonyl fluoride and hexafluoropropylene is different during the reaction, as shown in Table 6.

[0110] Table 6 Effect of different feed ratios on the addition reaction of hexafluoropropylene

[0111] As shown in Table 6, the feed ratio of carbonyl fluoride to hexafluoropropylene has a significant impact on product selectivity, but no significant impact on the conversion rate of hexafluoropropylene, which remains stable at 99.9% at all feed ratios. When the feed ratio is 1:1, the selectivity of heptafluoroisobutyryl fluoride is 94.5%, while the selectivity of the byproduct perfluoroheptanone is relatively high at 5.5%. With the increase of the carbonyl fluoride ratio, the selectivity of heptafluoroisobutyryl fluoride increases significantly, while the selectivity of perfluoroheptanone decreases accordingly. When the feed ratio reaches 3:1, the selectivity of heptafluoroisobutyryl fluoride increases to 99.2%, while the selectivity of perfluoroheptanone decreases to 0.8%. Further increasing the carbonyl fluoride ratio to 4:1 and 5:1 further slightly improves the selectivity, but the change tends to level off. Considering both raw material cost and separation energy consumption, a feed ratio of 3:1-5:1 is preferable, with 3:1 being the optimal process condition.

[0112] Application Example 35: Purification of Heptafluoroisobutyryl Fluoride A mixed feedstock containing 99.2% heptafluoroisobutyryl fluoride and 0.8% perfluoroheptanone was used. The feedstock gas was passed into a 10 L cold trap made of 316 L stainless steel. The cold trap temperature was controlled at -25 °C and the system pressure at 0.1 MPa. After 8 h of collection, 4.925 kg of crude heptafluoroisobutyryl fluoride was obtained. Gas chromatography analysis showed that the purity of the crude product was 99.75% and the collection yield was 98.5%.

[0113] The crude product was transferred to a pressurized distillation column (column diameter). A 150 mm diameter column with 30 theoretical plates (made of 316L stainless steel) was used. The system pressure was increased to 0.35 MPa, the reboiler temperature was controlled at 55℃, and the refrigerant temperature of the overhead condenser was set to -25℃. The system was operated under total reflux until the overhead temperature stabilized. The product was then collected at a reflux ratio of 2.5 and a collection rate of 0.5 kg / h, yielding a total of 4.81 kg of high-purity heptafluoroisobutyryl fluoride. The distillation yield was 96.2% based on the total heptafluoroisobutyryl fluoride in the crude product. GC analysis showed a product purity of 99.993% and a perfluoroheptanone residue of 67 ppm (gas chromatographic analysis results are shown in the figure). Figure 3 It can meet the requirements of high-purity chemical applications.

[0114] Catalyst lifetime evaluation To investigate the effect of boron and nitrogen co-doping modification on the stability of CsF / activated carbon catalysts, a fixed-bed lifetime evaluation comparative experiment was conducted on the unmodified catalyst (Comparative Example 3) and the modified catalyst (Example 4). A Monel fixed-bed reactor with an inner diameter of 25 mm and a length of 500 mm was used, and 20 mL of each of the catalysts from Example 4 and Comparative Example 3 were loaded. Reaction conditions: reaction temperature 140±2℃, reaction pressure 0.5±0.05 MPa, hexafluoropropylene to carbonyl fluoride feed volume ratio of 3:1, and total space velocity of feedstock 200 h⁻¹. -1(Based on catalyst volume). The reaction products were depressurized by a back pressure valve and then collected in a -25°C cold trap. Samples were taken every 50 hours for gas chromatography analysis, with hexafluoropropylene conversion and heptafluoroisobutyryl fluoride selectivity as evaluation indicators. Specific results are shown in Table 7.

[0115] Table 7 Catalyst lifetime evaluation

[0116] Table 7 shows that the modified catalyst CsF / AC-NB-F exhibits excellent catalytic stability. The initial hexafluoropropylene conversion rate was 99.9%, and the selectivity for heptafluoroisobutyryl fluoride was 99.2%. After 500 hours of continuous operation, the hexafluoropropylene conversion rate remained at 99.3%, and the selectivity for heptafluoroisobutyryl fluoride remained at 98.7%. Throughout the 500-hour evaluation period, no significant decline in catalyst activity was observed, demonstrating good long-term operational stability. The unmodified catalyst CsF / AC had an initial hexafluoropropylene conversion rate of 99.9%, but the initial selectivity was only 86.8%, with a high amount of byproduct formation. After 100 hours of operation, the conversion rate decreased to 96.2%, and the selectivity decreased to 84.2%. After 200 hours of operation, the conversion rate dropped sharply to 75.3%, and the selectivity decreased to 74.8%. In summary, the CsF / AC-NB-F catalyst prepared by the present invention through B and N co-doping modified activated carbon support exhibits both high selectivity and excellent long-term stability in the addition reaction of hexafluoropropylene to prepare heptafluoroisobutyryl fluoride, and has significant industrial application value.

[0117] The description in this disclosure is provided for illustrative and descriptive purposes only and is not intended to be exhaustive or to limit the disclosure to its forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of this disclosure and to enable those skilled in the art to understand this disclosure and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A highly selective catalyst for the preparation of heptafluoroisobutyryl fluoride, comprising a support and a metal active component supported on the support; wherein The active metal component is selected from any one or two or more of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Y, Sc, Cr and Mo.

2. The high selectivity catalyst of claim 1, wherein, The loading amount of the metal active component on the carrier is 1~30wt%; preferably 8~30wt%.

3. The high selectivity catalyst of claim 1 or 2, wherein, The carrier is modified and / or unmodified activated carbon; The modified activated carbon includes nitrogen-doped activated carbon and / or boron-doped activated carbon; Preferably, the nitrogen doping amount in the modified activated carbon is 0.5~10 wt%; The modified activated carbon contains 0.1 to 5 wt% boron.

4. The high selectivity catalyst of claim 3, wherein, The preparation method of modified activated carbon includes: acid washing treatment, high temperature solid phase doping treatment and pre-fluorination treatment of unmodified activated carbon; Preferably, the pickling treatment uses hydrochloric acid and / or nitric acid, and preferably the mass percentage of the hydrochloric acid and / or nitric acid in the solution is 1-20 wt%; and / or The pickling temperature is 60~90℃; and / or The pickling process takes 4-8 hours. Preferably, the temperature of the high-temperature solid-phase doping treatment is 500~1200℃; and / or The high-temperature solid-phase doping treatment time is 0.5~5h; and / or During the high-temperature solid-phase doping treatment, a nitrogen precursor is added, preferably selected from any one or more of urea, melamine, or dicyandiamide; During the high-temperature solid-phase doping treatment, a boron precursor is added, preferably selected from any one or more of boric acid, amorphous boron, or boron carbide; Preferably, the prefluorination treatment is carried out in the presence of hydrogen fluoride, more preferably in the presence of a mixture of hydrogen fluoride and an inert gas, and more preferably, the hydrogen fluoride in the mixture is 1-20 vol.%, preferably 5-15 vol.%; and / or The pre-fluorination treatment is performed at a temperature of 200~400℃; and / or The pre-fluorination treatment takes 2 to 6 hours.

5. A method for preparing a highly selective catalyst for preparing heptafluoroisobutyryl fluoride according to any one of claims 1 to 4, comprising the following steps: The carrier is immersed in a solution of a metal active component containing a metal active component, thereby loading the metal active component onto the carrier; It is then activated by heating in an inert gas environment.

6. The production method according to claim 5, wherein The volume ratio of the metal active component solution to the carrier is (1~2):1; and / or The soaking time is 15-36 hours.

7. The production method according to claim 5 or 6, wherein The activation temperature is 100~300℃; and / or The activation time is 1~24h.

8. A method of making heptafluoroisobutyryl fluoride comprising: Hexafluoropropylene and carbonyl fluoride are subjected to an addition reaction under the catalysis of the catalysts according to any one of claims 1 to 4 and / or the catalysts prepared by the preparation methods according to any one of claims 5 to 7.

9. The method of claim 8, wherein, The feed volume ratio of carbonyl fluoride and hexafluoropropylene is (1~10):1; and / or In the addition reaction, the feed volume hourly space velocity of hexafluoropropene and carbonyl fluoride is 36~360 h -1 .

10. The method according to claim 8 or 9, wherein, The temperature of the addition reaction is 50~200℃; preferably 130~150℃.

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