A method for preparing hexafluoroacetone by isomerization of hexafluoropropylene oxide

Abstract

The present invention relates to the field of catalysts, and particularly to a SO 4 2‑ / ZrO 2 -M x O y catalyst, its preparation and its application in the synthesis of hexafluoroacetone. A method for preparing hexafluoroacetone by isomerization of hexafluoropropylene oxide is disclosed. The SO 4 2‑ / ZrO 2 -M x O y catalyst activation and regeneration method. The hexafluoropropylene oxide isomerization to hexafluoroacetone reaction involving this catalyst has the characteristics of high space velocity, high catalytic efficiency, no by-products, strong activation and regeneration ability, and can be catalyzed at room temperature, with remarkable economy, suitable for large-scale production. Moreover, this catalyst has a long service life, simple activation steps, and reliable regeneration performance.

Description

Technical Field

[0001] The present invention relates to the field of catalysts, and particularly relates to the application of a SO 4 2- / ZrO 2 -M x O y catalyst in the synthesis of hexafluoroacetone, and discloses a method for preparing hexafluoroacetone by isomerization of hexafluoropropylene oxide. Background Art

[0002] Hexafluoroacetone can be used to synthesize various high-value fluorine-containing compounds. For example, bisphenol AF prepared from hexafluoroacetone has been widely used in the production of fluororubber. 6FDA synthesized from hexafluoroacetone is used as an important monomer of fluorinated polyimide and has a wide range of applications in optical communication, flexible display screens, solar cell substrates, organic flexible transparent conductive film substrates, etc. Hexafluoroisopropanol obtained by hydrogenation reduction of hexafluoroacetone is used as a high-grade solvent and a monomer of high-performance fluorine-containing elastomers, and can further synthesize the new inhaled anesthetic sevoflurane. The main technical methods for synthesizing hexafluoroacetone include the rearrangement method of hexafluoropropylene oxide, the oxidation method of octafluoroisobutene, the high-catalytic fluorination method of hexachloroacetone, and the oxidation method of dithiohexafluoroacetone dimer. Among them, the rearrangement method of hexafluoropropylene oxide is the main method for industrial production of hexafluoroacetone at present.

[0003] Patent No. US3321515 discloses the catalysts used in the rearrangement method of hexafluoropropylene oxide, such as Al 2 O 3 、TiO 2 、WO 2 、AlCl 3 、AlBr 3 、SnCl 4 、VoCl 3 、TiCl 4 、FeCl 3 、CuCl 2 、ZrOCl 2 etc. However, it is necessary to introduce an inert gas to dilute the raw material hexafluoropropylene oxide. At the same gas flux, hexafluoropropane only accounts for a part of the gas flow rate, and the conversion rate of hexafluoropropylene oxide is not high. US4579974 etc. describe a continuous catalytic method for preparing hexafluoroacetone by fluorinating hexachloroacetone with anhydrous hydrogen fluoride in the gas phase. This method requires the use of hydrogen fluoride, which is a high-risk substance and is likely to cause harm to production personnel. Patent CN111116342A discloses a catalyst for preparing hexafluoroacetone by isomerization method, its preparation method and application, and the reaction space velocity of the catalyst is 100-600h -1 , and the reaction space velocity of the catalyst is relatively low. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a method for isomerizing hexafluoropropylene oxide to hexafluoroacetone with less or no by-products, especially HF, the reaction being based on the use of a catalyst in the reaction. The positive effect of the catalyst on isomerization of hexafluoropropylene oxide to hexafluoroacetone is also reflected in the large reaction space velocity, the reaction being able to react at room temperature, and the absence of the need for mixing and diluting with an inert gas, and the conversion rate and selectivity being relatively ideal compared to the prior art.

[0005] The present invention solves the above problems. In a first aspect, the present invention provides a method of 4 2- / ZrO 2 -M x O y The catalyst represented by

[0006] In the general formula, x is a positive integer of 1 to 3, y is a positive integer of 2 or 4, and M is any one of Cr, Al, Ti, Fe, Ni, Sn or Ce.

[0007] In a second aspect, the present invention further provides a general formula of SO 4 2- / ZrO 2 -M x O y Preparation method:

[0008] S1: ZrOCl 2 8H 2 O and soluble M metal salt are dissolved in deionized water in an equal molar ratio to obtain a mixed solution, and then ammonia water is added dropwise under stirring until the pH value reaches 9.

[0009] S2: Aging at room temperature for one day, filtering the precipitate, washing with deionized water to remove chloride ions, and soaking the solid in dilute sulfuric acid after drying, filtering, and drying.

[0010] S3: The dried product of the previous step is roasted, powdered, tableted, crushed, and sieved catalyst particles.

[0011] In some embodiments, in the catalyst preparation method provided in the second aspect, the soluble M metal salt in step S1 can be selected from MCl 2y / x ·zH 2 O or M (NO 3 ) 2y / x ·zH 2 O, wherein x is a positive integer from 1 to 3, y is any positive integer from 1 to 3, and z is any of 1, 6, 8, and 9;

[0012] In some embodiments, in the catalyst preparation method provided in the second aspect, the pH is adjusted in step S1 by using any one of ammonia water, dihydrogen phosphate, dihydrogen phosphate, and sodium carbonate.

[0013] In some embodiments, in the catalyst preparation method provided in the second aspect, in step S3, the pH is adjusted to 8.5 to 11, further adjusted to 8.5 to 9.5, and still further to 9, and the soaking time is about 1 h.

[0014] In some embodiments, in the catalyst preparation method provided in the second aspect, in step S3 of the acid leaching, any one of sulfuric acid, nitric acid, and hydrochloric acid is used for soaking.

[0015] In some embodiments, in the catalyst preparation method provided in the second aspect, the acid concentration in step S3 is 0.4 to 0.6 mol / L, preferably 0.45 mol to 0.55 mol / L, and particularly preferably 0.5 mol / L.

[0016] In some embodiments, in the catalyst preparation method provided in the second aspect, the acid soaking time in step S3 is 0.5 to 2 h, further 0.5 to 1 h, and still further 1 h.

[0017] In some embodiments, in the catalyst preparation method provided in the second aspect, the calcination step of S3 is to use a muffle furnace to calcine at about 200 °C to about 800 °C for 3 h. For a more refined catalyst preparation process, the sieving of S3 uses a 20-40 mesh sieve.

[0018] The third aspect of the present invention also discloses the application of the catalyst of the first aspect in the isomerization of hexafluoropropylene oxide to prepare hexafluoroacetone, including:

[0019] S1: Hexafluoropropylene oxide is introduced into a fixed-bed reactor filled with the catalyst, as shown in reaction formula (I):

[0020]

[0021] S2: The reaction product of formula (I) is introduced into water, and the solution is distilled to collect the fraction of hexafluoroacetone trihydrate.

[0022] In some embodiments, for the application of the catalyst of the first aspect, the reaction temperature can be 0-45 °C.

[0023] In some embodiments, for the application of the catalyst of the first aspect, the reaction space velocity is 700-900 h -1 .

[0024] In some embodiments, for the application of the catalyst of the first aspect, the distillation temperature of the hexafluoroacetone aqueous solution is about 105 °C to about 106 °C.

[0025] The third aspect of the present invention also discloses the regeneration method of the catalyst of the first aspect, including,

[0026] Step 1: SO4 2- / ZrO 2 -M x O y The acid solution in which the catalyst is immersed

[0027] Step 2: Use N 2 / O 2 The mixed gas to SO 4 2- / ZrO 2 -M x O y Regenerate the catalyst

[0028] Step 3: Calcination, introduce inert gas, cool naturally, and pulverize and screen

[0029] In some embodiments, for the regeneration method of the catalyst in the first aspect, the acid solution in step 1 is 0.5 - 0.7 mol / L, preferably 0.6 mol / L

[0030] In some embodiments, for the regeneration method of the catalyst in the first aspect, the acid immersion time in step 1 is 30 - 60 min, preferably 30 min

[0031] In some embodiments, for the regeneration method of the catalyst in the first aspect, the volume ratio V 2 / O 2 In the N N2 ∶V O2 Of the mixed gas is 1∶1 - 1∶4, preferably 1∶2 - 1∶3, and particularly preferably 1∶2

[0032] In some embodiments, for the regeneration method of the catalyst in the first aspect, the calcination temperature in step 3 is 400 - 500 °C, preferably 450 °C

[0033] In some embodiments, for the regeneration method of the catalyst in the first aspect, the calcination time is 5 - 7 h, preferably 6 h

[0034] In some embodiments, for the regeneration method of the catalyst in the first aspect, the inert gas is nitrogen or argon

[0035] In some embodiments, for the regeneration method of the catalyst in the first aspect, the mesh number of screening is 10 - 40 meshes, preferably 20 - 40 meshes

[0036] The reagents used in the present invention are all purchased from the open and legal market, and no further purification and optimization are carried out

[0037] Advantages of the present invention

[0038] (1) The catalytic efficiency of the complex is high and the amount of catalyst used is small

[0039] (2) The catalytic conditions are mild. The isomerization of hexafluoropropylene oxide to prepare hexafluoroacetone can be carried out in the range of 20 - 60 °C.

[0040] (3) The catalytic reaction is relatively specific, with few side reactions and high yields.

[0041] (4) The catalyst has good renewable ability and toxicity resistance.

[0042] (5) In the case of combined use of catalysts, the reaction space velocity increases relative to the use of a single catalyst alone. Description of the Drawings

[0043] Figure 1 Gas chromatogram of hexafluoroacetone in Example 1

[0044] Figure 2 Gas chromatogram of hexafluoroacetone in Example 2 Detailed Description of the Invention

[0045] The following examples can further describe the present invention. However, these examples should not be construed as limiting the scope of the present invention.

[0046] The present invention discloses a preparation method of the catalyst:

[0047] S1: ZrOCl 2 ·8H 2 O and a soluble M metal salt can be selected from one of MCl 2y / x ·zH 2 O or M(NO 3 ) 2y / x ·zH 2 O, etc. are dissolved in deionized water in an equimolar ratio to obtain a mixed solution, and then ammonia water is added dropwise under stirring until the pH value reaches 9.0 - 11.

[0048] S2: Aging for one day at room temperature, filtering the generated precipitate, washing with deionized water to remove chloride ions, soaking the solid after drying in a sulfuric acid or hydrochloric acid solution with a concentration of 0.4 - 0.6 mol / L for 1 h, filtering, and drying.

[0049] S3: The dried product from the previous step is calcined in a muffle furnace at 400 - 600 °C for 3 - 6 h, the powder is pressed into tablets, crushed, and sieved through a 20 - 60 mesh to obtain catalyst particles.

[0050] The present invention discloses the application of the catalyst in the preparation of hexafluoroacetone from hexafluoropropylene oxide:

[0051] SO 4 2- / ZrO 2 -M x O yThe catalyst particles are placed in a gas-phase reaction tube made of 316L stainless steel with an inner diameter of 10 mm and a length of 400 mm. Hexafluoropropylene oxide gas is introduced at 0 - 45 °C, and the space velocity is 800 h -1 -1200 h -1 . The reaction product is taken for gas chromatography analysis, then introduced into water for absorption, and the absorption solution is distilled. The fraction at 105 - 106 °C is collected to obtain hexafluoroacetone trihydrate. The conversion rate of hexafluoropropylene oxide and the selectivity of hexafluoroacetone are detected by gas chromatography analysis.

[0052] The present invention discloses the activation and regeneration of the catalyst in the preparation of hexafluoroacetone from hexafluoropropylene oxide:

[0053] S1: The deactivated catalyst is immersed in a sulfuric acid solution with a concentration of 0.5 - 0.7 mol / L for 30 minutes.

[0054] S2: N2 with a volume ratio of 1:2 - 1:3 is introduced 2 / O 2 . It is calcined at a temperature of 450 °C for 3 hours.

[0055] S2: N2 is introduced 2 , the temperature is kept constant at 750 °C for 1 h. After natural cooling in a nitrogen atmosphere, it is crushed and sieved to 20 - 40 mesh.

[0056] Gas chromatography analysis conditions: capillary column CP-PoraPLOTQ (50 m × 0.32 mm × 10 μm), the carrier gas is high-purity nitrogen, FID detector,

[0057] The carrier gas is N2 2 , the flow rate ratio of nitrogen to hydrogen is 1:1, the hydrogen flow rate is (20 - 40) ml / min, the hydrogen-to-air ratio is 1:10, injection port: 220 °C; column oven: 150 °C; detector: 220 °C;

[0058] The catalyst life of the present invention is as high as 800 - 1000 hours, and the activation and regeneration method is simple and reliable.

[0059] The maximum catalytic efficiency of each different metal M of the present invention at the optimal catalytic temperature:

[0060]

[0061]

[0062] Example 1

[0063] ZrOCl 2 ·8H 2 O and CrCl 3 ·6H 2O is dissolved in deionized water in an equimolar ratio to obtain a mixed solution. Then, ammonia water is added dropwise under stirring until the pH value reaches 9. It is aged at room temperature for one day. The resulting precipitate is filtered, washed with deionized water to remove chloride ions, soaked in 0.45 mol / L sulfuric acid after drying the solid, filtered and dried. The dried product of the previous step is calcined at 500 °C for 4 h, the powder is pressed into tablets, crushed, and sieved to obtain catalyst particles with a mesh size of 30 - 50.

[0064] The reaction is carried out in a fixed-bed reactor. SO 4 2- / ZrO 2 -Cr 2 O 3 The catalyst particles are placed in a gas-phase reaction tube made of 316L stainless steel with an inner diameter of 10 mm and a length of 400 mm. Heptafluoropropylene oxide gas is introduced at 20 °C, and the reaction space velocity is 700 - 750 h -1 , the reaction product is taken for gas chromatography analysis, then introduced into water for absorption, and the pH value is neutral. The absorption solution is distilled, and the fraction at 105 - 106 °C is collected to obtain hexafluoroacetone trihydrate. By chromatographic analysis, the conversion rate of heptafluoropropylene oxide is 99.71%, and the selectivity of hexafluoroacetone is 99.63%.

[0065] Example 2

[0066] ZrOCl 2 ·8H 2 O and CeCl 3 ·6H 2 O are dissolved in deionized water in a molar ratio to obtain a mixed solution. Then, sodium dihydrogen phosphate and disodium hydrogen phosphate are added dropwise under stirring until the pH value reaches 9. It is aged at room temperature for one day. The resulting precipitate is filtered, washed with deionized water to remove chloride ions, soaked in 0.5 mol / L sulfuric acid after drying the solid, filtered and dried. The dried product of the previous step is calcined at 400 °C for 5 h, the powder is pressed into tablets, crushed, and sieved to obtain catalyst particles with a mesh size of 20 - 50.

[0067] The reaction is carried out in a fixed-bed reactor. SO 4 2- / ZrO 2 -Ce 2 O 3 The catalyst particles are placed in a gas-phase reaction tube made of 316L stainless steel with an inner diameter of 10 mm and a length of 400 mm. Heptafluoropropylene oxide gas is introduced at 5 °C, and the reaction space velocity is 700 - 800 h -1, The reaction product was subjected to gas chromatography analysis, then passed into water for absorption, with the pH value being neutral. The absorption solution was distilled, and the fraction at 105 - 106 °C was collected to obtain hexafluoroacetone trihydrate. By chromatographic analysis, the conversion rate of hexafluoropropylene oxide was 96.25%, and the selectivity of hexafluoroacetone was 99.72%.

[0068] Example 3

[0069] ZrOCl 2 ·8H 2 O and PbCl 2 were dissolved in deionized water in an equimolar ratio to obtain a mixed solution. Then, ammonia water was added dropwise under stirring until the pH value reached 9, and it was aged at room temperature for one day. The resulting precipitate was filtered, washed with deionized water to remove chloride ions, the solid was dried and then soaked in 0.55 mo1 / L sulfuric acid, filtered and dried. The dried product from the previous step was calcined at 600 °C for 3 h, the powder was tableted, crushed, and sieved to obtain catalyst particles with a mesh size of 30 - 40.

[0070] The reaction was carried out in a fixed-bed reactor. The SO 4 2- / ZrO 2 -PbO catalyst particles were placed in a gas-phase reaction tube made of 316L stainless steel with an inner diameter of 10 mm and a length of 400 mm. Hexafluoropropylene oxide gas was introduced at 35 °C, and the reaction space velocity was 750 - 900 h -1 , The reaction product was subjected to gas chromatography analysis, then passed into water for absorption, with the pH value being neutral. The absorption solution was distilled, and the fraction at 105 - 106 °C was collected to obtain hexafluoroacetone trihydrate. By chromatographic analysis, the conversion rate of hexafluoropropylene oxide was 99.86%, and the selectivity of hexafluoroacetone was 99.59%.

[0071] Example 4

[0072] ZrOCl 2 ·8H 2 O and Zn(NO 3 ) 2 ·6H 2 O were dissolved in deionized water in an equimolar ratio to obtain a mixed solution. Then, ammonia water was added dropwise under stirring until the pH value reached 10, and it was aged at room temperature for one day. The resulting precipitate was filtered, washed with high-purity water to remove chloride ions, the solid was dried and then soaked in 0.6 mol / L sulfuric acid, filtered and dried. The dried product from the previous step was calcined at 500 °C for 3 h, the powder was tableted, crushed, and sieved to obtain catalyst particles with a mesh size of 20 - 45.

[0073] The reaction was carried out in a fixed-bed reactor. The SO 4 2- / ZrO 2- The ZnO catalyst particles were placed in a gas-phase reaction tube made of 316L stainless steel with an inner diameter of 10 mm and a length of 400 mm. Heptafluoropropylene oxide gas was introduced at 10 °C, and the space velocity was 700 - 750 k -1 , and the reaction products were subjected to gas chromatography analysis. Then, they were introduced into water for absorption, and the pH value was neutral. The absorption solution was distilled, and the fraction at 105 - 106 °C was collected to obtain hexafluoroacetone trihydrate. By chromatographic analysis, the conversion rate of heptafluoropropylene oxide was 99.92%, and the selectivity of hexafluoroacetone was 98.84%.

[0074] Example 5

[0075] ZrOCl 2 ·8H 2 O and SnCl 4 ·5H 2 O were dissolved in deionized water in an equimolar ratio to obtain a mixed solution. Then, ammonia water was added dropwise under stirring until the pH value reached 9.5. The mixture was aged at room temperature for one day, and the resulting precipitate was filtered. The precipitate was washed with deionized water to remove chloride ions. After drying the solid, it was soaked in 0.65 mol / L sulfuric acid, filtered, and dried. The dried product from the previous step was calcined at 550 °C for 3 h, the powder was pressed into tablets, crushed, and sieved to obtain catalyst particles with a size of 20 - 40 mesh.

[0076] The reaction was carried out in a fixed-bed reactor. The SO 4 2- / ZrO 2 -SnO 2 catalyst particles were placed in a gas-phase reaction tube made of 316L stainless steel with an inner diameter of 10 mm and a length of 400 mm. Heptafluoropropylene oxide gas was introduced at 40 °C, and the reaction space velocity was 700 - 800 h -1 , and the reaction products were subjected to gas chromatography analysis. Then, they were introduced into water for absorption, and the pH value was neutral. The absorption solution was distilled, and the fraction at 105 - 106 °C was collected to obtain hexafluoroacetone trihydrate. By chromatographic analysis, the conversion rate of heptafluoropropylene oxide was 99.92%, and the selectivity of hexafluoroacetone was 99.34%.

[0077] Example 6

[0078] ZrOCl 2 ·8H 2 O and Al(NO 3 ) 3 ·9H 2O is dissolved in deionized water in an equimolar ratio to obtain a mixed solution. Then, ammonia water is added dropwise under stirring until the pH value reaches 8.5. It is aged at room temperature for one day, washed with deionized water to remove chloride ions, soaked in 0.6 mol / L sulfuric acid after drying the solid, filtered, dried, and the dried product from the previous step is calcined at 500 °C for 3 h, pressed into tablets, crushed, and sieved to obtain catalyst particles with a mesh size of 20 - 40.

[0079] The reaction is carried out in a fixed-bed reactor. SO 4 2- / ZrO 2 -Al 2 O 3 The catalyst particles are placed in a gas-phase reaction tube made of 316L stainless steel with an inner diameter of 10 mm and a length of 400 mm. Heptafluoropropylene oxide gas is introduced at 10 °C, and the reaction space velocity is 700 - 800 h -1 . The reaction product is taken for gas chromatography analysis, then introduced into water for absorption, and the pH value is neutral. The absorption solution is distilled, and the fraction at 105 - 106 °C is collected to obtain hexafluoroacetone trihydrate. By chromatographic analysis, the conversion rate of heptafluoropropylene oxide is 98.71%, and the selectivity of hexafluoroacetone is 98.68%.

[0080] Example 7

[0081] After preparing an aqueous solution of ZrOCl 2 ·8H 2 O, an equimolar amount of TiCl 4 is slowly added dropwise to the ZrOCl 2 solution. Then, ammonia water is added dropwise under stirring until the pH value reaches 9. It is aged at room temperature for one day, and the resulting precipitate is filtered, washed with deionized water to remove chloride ions, soaked in 0.65 mol / L sulfuric acid after drying the solid, filtered, dried, and the dried product from the previous step is calcined at 500 °C for 3 h, pressed into tablets, crushed, and sieved to obtain catalyst particles with a mesh size of 20 - 40.

[0082] The reaction is carried out in a fixed-bed reactor. SO 4 2- / ZrO 2 -TiO 2 The catalyst particles are placed in a gas-phase reaction tube made of 316L stainless steel with an inner diameter of 10 mm and a length of 400 mm. Heptafluoropropylene oxide gas is introduced at 30 °C, and the reaction space velocity is 850 - 900 h -1 . The reaction product is taken for gas chromatography analysis, then introduced into water for absorption, and the pH value is neutral. The absorption solution is distilled, and the fraction at 105 - 106 °C is collected to obtain hexafluoroacetone trihydrate. By chromatographic analysis, the conversion rate of heptafluoropropylene oxide is 96.42%, and the selectivity of hexafluoroacetone is 99.05%.

[0083] Example 8

[0084] Dissolve ZrOCl 2 ·8H 2 O and FeCl 3 ·8H 2 O in deionized water in equimolar ratio to obtain a mixed solution. Then, dropwise add ammonia water under stirring until the pH value reaches 11, age for one day at room temperature, filter the resulting precipitate, wash with deionized water to remove chloride ions, soak the solid after drying with 0.5 mol / L sulfuric acid, filter and dry, and calcine the dried product from the previous step at 500 °C for 3 h, press the powder into tablets, crush, and sieve to obtain catalyst particles with a mesh size of 20 - 40.

[0085] The reaction is carried out in a fixed-bed reactor. Place the SO 4 2- / ZrO 2 -Fe 2 O 3 catalyst particles in a gas-phase reaction tube made of 316L stainless steel with an inner diameter of 10 mm and a length of 400 mm. Introduce hexafluoropropylene oxide gas at 15 °C, and the reaction space velocity is 750 - 800 h -1 . Take the reaction product for gas chromatography analysis, then introduce it into water for absorption until the pH value is neutral. Distill the absorption liquid and collect the fraction at 105 - 106 °C to obtain hexafluoroacetone trihydrate. By chromatographic analysis, the conversion rate of hexafluoropropylene oxide is 98.98%, and the selectivity of hexafluoroacetone is 99.3%.

[0086] Example 9

[0087] Example of catalyst regeneration:

[0088] According to Example 1, the catalyst SO 4 2- / ZrO 2 -Cr 2 O 3 is continuously used for 1000 h, with a conversion rate of 96.25% and a selectivity of 97.58%.

[0089] For the regeneration of the catalyst, immerse the SO 4 2- / ZrO 2 -Cr 2 O 3 with reduced activity into a 0.6 mol / L sulfuric acid solution for 30 minutes. Use N 2 / O 2 gas with a ratio of 1:2 - 1:3 to regenerate the catalyst. After calcining at 450 °C for 6 hours, introduce N 2, at a constant temperature of 750 °C for 1 h, and after natural cooling in a nitrogen atmosphere, it is pulverized to pass through a 20-40 mesh sieve, and the regeneration of the catalyst can be completed after pulverization.

[0090] According to Example 1, the regenerated catalyst is used for the catalytic reaction, with a conversion rate of 99.25% and a selectivity of 99.69%.

[0091] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A kind of SO 4 2- / ZrO 2 -M x O y Application of the catalyst in the isomerization of hexafluoropropylene oxide to prepare hexafluoroacetone It is characterized in that including: Step 1: Hexafluoropropylene oxide is introduced into a fixed-bed reactor containing SO 4 2- / ZrO 2 -M x O y catalyst for reaction, as shown in Equation (A), ； Step 2: The reaction product of formula (A) is introduced into water, the solution is distilled, and the fraction hexafluoroacetone trihydrate is collected. The said SO 4 2- / ZrO 2 -M x O y The preparation method of the catalyst is as follows: S1: Mix and dissolve ZrOCl 2 ·8H 2 O and soluble salts of metal M, and adjust the pH value; S2: Let it stand, filter, and wash the filter cake. S3: Dry the filter cake, soak it in acid solution, dry it, roast it, tablet it, crush it, and sieve it to obtain the catalyst SO 4 2- / ZrO 2 -M x O y ; Among them, the soluble M metal salt input in step S1 is CrCl 3 ·6H 2 O, CeCl 3 ·6H 2 O, PbCl 2 , Zn(NO 3 ) 2 ∙6H 2 O, SnCl 4 ·5H 2 O, Al(NO 3 ) 3 ·9H 2 O or TiCl 4 , and the catalyst SO 4 2- / ZrO 2 -Cr 2 O 3 , SO 4 2- / ZrO 2 -Ce 2 O 3 , SO 4 2- / ZrO 2 -PbO, SO 4 2- / ZrO 2 -ZnO, SO 4 2- / ZrO 2 -SnO 2 , SO 4 2- / ZrO 2 -Al 2 O 3 , SO 4 2- / ZrO 2 -TiO 2 .

2. Use of the SO 4 2- / ZrO 2 -M x O y catalyst in the isomerization of hexafluoropropylene oxide to prepare hexafluoroacetone It is characterized in that The reaction space velocity of the said Step 1 is 700-900 h -1 .

3. The application of the SO 4 2- / ZrO 2 -M x O y catalyst in the isomerization of hexafluoropropylene oxide to prepare hexafluoroacetone, It is characterized in that The reaction space velocity in Step 1 is 850-900 h -1 .

4. Use of the SO 4 2- / ZrO 2 -M x O y catalyst in the isomerization of hexafluoropropylene oxide to prepare hexafluoroacetone It is characterized in that The distillation temperature in Step 2 is 100°C to 120°C.

5. Use of the SO 4 2- / ZrO 2 -M x O y catalyst in the isomerization of hexafluoropropylene oxide to prepare hexafluoroacetone It is characterized in that The distillation temperature in Step 2 is 105 to 110°C.

6. Use of the SO 4 2- / ZrO 2 -M x O y catalyst in the isomerization of hexafluoropropylene oxide to prepare hexafluoroacetone It is characterized in that The distillation temperature in Step 2 is 105 to 106°C.

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