Preparation method of hexafluoroacetone trihydrate
By using 2,2-difluoropropane and metal oxide photocatalyst in the photoreactor, the low efficiency and high cost problems of the hexafluoropropane oxide rearrangement method in the prior art are solved, and the problem of the hexafluoropropane oxide rearrangement method is realized. The preparation of hexafluoroacetone trihydrate with high purity and high yield has broad application prospects.
Patent Information
- Application Number
- CN202411119961.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-15
- Publication Date
- 2024-12-27
AI Technical Summary
The existing hexafluoropropylene oxide rearrangement method has low conversion and selectivity and low raw material utilization, which limits its industrial application.
The photocatalytic oxidation reaction is carried out in the photo reactor using 2,2-difluoropropane and metal oxide photocatalyst. The resulting exhaust gas is absorbed in water and is distilled by atmospheric pressure to obtain hexafluoroacetone trihydrate. The reaction conditions are mild and the cost is relatively high. Low.
The high purity (over 98%) and high yield (over 72%) of hexafluoroacetone trihydrate are achieved, with higher preparation efficiency and lower cost, and have better economic benefits compared with the prior art.
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Figure CN119191948A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of fluorine chemistry, and in particular to a method for preparing hexafluoroacetone trihydrate. Background Art
[0002] Hexafluoroacetone, as an important fluorine-containing intermediate, is widely used in the synthesis of a variety of high value-added fluorine-containing compounds. For example, bisphenol AF, as a key fluorine-containing crosslinking agent, is indispensable in the rubber industry and can significantly improve the properties of rubber products such as resistance to compression deformation, chemical corrosion resistance and thermal stability. Hexafluoroacetone can also be used to prepare hexafluorodianhydride, which is an important monomer for the synthesis of polyimides, which are widely used in optical fields such as light guides, waveguides and liquid crystals. In addition, hexafluoroisopropanol can be obtained by reduction reaction of hexafluoroacetone. Hexafluoroisopropanol is not only an advanced solvent and an important monomer for high-performance fluorine-containing elastomers, but also a key intermediate for the synthesis of a new inhalation anesthetic, sevoflurane.
[0003] The preparation methods of hexafluoroacetone include hexafluoropropylene oxide rearrangement method, octafluoroisobutylene oxidation method, hexachloroacetone catalytic fluorination method and disulfide hexafluoroacetone oxidation method according to the different raw materials. Among these methods, only the hexafluoropropylene oxide rearrangement method is widely used in industrial production and has become the main production technology route. At present, hexafluoropropylene oxide is mainly prepared by oxidation reaction with hexafluoropropylene as raw material in industry. The conditions of the oxidation reaction are harsh, the conversion rate and selectivity are general, and the raw material utilization rate is not high, which limits the application of the hexafluoropropylene oxide rearrangement method to prepare hexafluoroacetone.
[0004] Therefore, there is an urgent need for an economical and efficient method for preparing hexafluoroacetone trihydrate. Summary of the invention
[0005] The technical problem to be solved by the present invention is to provide a method for preparing hexafluoroacetone trihydrate which is economical, efficient, high in purity and high in yield.
[0006] In order to solve the above technical problems, the present invention provides a method for preparing hexafluoroacetone trihydrate, comprising the following steps:
[0007] Mixing 2,2-dichlorohexafluoropropane, an organic solvent and a metal oxide serving as a photocatalyst in a photoreactor;
[0008] The mixture is stirred until the photocatalyst is in a suspended state to obtain a suspension;
[0009] Irradiate the suspension with a light source and introduce oxygen to react at room temperature;
[0010] The tail gas produced by the reaction is passed into water for absorption;
[0011] The tail gas absorption liquid is distilled at normal pressure to obtain hexafluoroacetone trihydrate.
[0012] Furthermore, the photocatalyst is one of TiO2, ZnO, Fe2O3, ZrO2, SnO2, and WO3.
[0013] Furthermore, the molar ratio of the photocatalyst to 2,2-dichlorohexafluoropropane is 1:10 to 1:100.
[0014] Furthermore, the organic solvent is one of dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, hexamethylphosphoric triamide, acetonitrile and tetrahydrofuran.
[0015] Furthermore, the mass ratio of the organic solvent to 2,2-dichlorohexafluoropropane is 10:1 to 1:1.
[0016] Furthermore, the light source is one of a xenon lamp, a mercury lamp, an LED lamp and sunlight.
[0017] Furthermore, the power of the light source is 100-300W.
[0018] Furthermore, the oxygen introduction rate is 0.5 to 1.5 L / h.
[0019] Furthermore, the reaction time at room temperature is 5 to 24 hours.
[0020] Furthermore, the tail gas absorption liquid is distilled at atmospheric pressure to collect a fraction at 105-106° C. to obtain hexafluoroacetone trihydrate.
[0021] The invention provides a method for preparing hexafluoroacetone trihydrate. 2,2-dichlorohexafluoropropane is used as a raw material, a metal oxide semiconductor material is used as a photocatalyst, an oxidation reaction occurs under light, and the reaction tail gas is absorbed and then distilled to obtain the hexafluoroacetone trihydrate. The reaction conditions in the preparation process are mild and easy to control, the preparation cost is low, and the method is economical and efficient.
[0022] Moreover, 2,2-dichlorohexafluoropropane can be obtained by adding hexafluoropropylene to chlorine to obtain 1,2-dichlorohexafluoropropane, and 1,2-dichlorohexafluoropropane can be rearranged by chlorine atoms under the catalysis of aluminum fluoride to obtain the rearrangement product 2,2-dichlorohexafluoropropane in high yield. The preparation of 2,2-dichlorohexafluoropropane is more economical and efficient than the industrial preparation of hexafluoropropylene oxide with hexafluoropropylene. Therefore, the preparation method of hexafluoroacetone trihydrate provided by the present invention is higher in preparation efficiency, lower in cost and better in economic benefit than the most commonly used hexafluoropropylene oxide rearrangement method for preparing hexafluoroacetone. The preparation method of hexafluoroacetone trihydrate provided by the present invention has broad application prospects and is worthy of popularization and application.
[0023] At the same time, the present invention provides a method for preparing hexafluoroacetone trihydrate, using a metal oxide semiconductor material as a photocatalyst. The hexafluoroacetone trihydrate finally prepared has not only high purity but also relatively high yield. The purity of the obtained hexafluoroacetone trihydrate is above 98% and the yield is above 72%. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 A flow chart of a method for preparing hexafluoroacetone trihydrate provided in an embodiment of the present invention. DETAILED DESCRIPTION
[0025] See also Figure 1 The present invention provides a method for preparing hexafluoroacetone trihydrate, comprising the following steps:
[0026] Step 1) 2,2-dichlorohexafluoropropane, an organic solvent and a metal oxide serving as a photocatalyst are mixed in a photoreactor.
[0027] Wherein, 2,2-dichlorohexafluoropropane is prepared by the following method:
[0028] First, hexafluoropropylene is reacted with chlorine to obtain 1,2-dichlorohexafluoropropane;
[0029] Then, 1,2-dichlorohexafluoropropane is subjected to chlorine atom rearrangement under the catalysis of aluminum chlorofluoride to obtain 2,2-dichlorohexafluoropropane.
[0030] Among them, the photocatalyst is one of metal oxide semiconductor materials such as TiO2, ZnO, Fe2O3, ZrO2, SnO2, WO3, etc.
[0031] Furthermore, in order to achieve the best catalytic effect, the molar ratio of the photocatalyst to 2,2-dichlorohexafluoropropane is controlled to be 1:10 to 1:100.
[0032] The organic solvent is one of dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, hexamethylphosphoric triamide, acetonitrile and tetrahydrofuran.
[0033] In order to fully dissolve 2,2-dichlorohexafluoropropane, the mass ratio of the organic solvent to 2,2-dichlorohexafluoropropane is controlled to be 10:1 to 1:1.
[0034] Among them, since the boiling points of the raw materials 2,2-dichlorohexafluoropropane and the organic solvent are relatively low, in order to reduce the loss of raw materials during the preparation process in the future, the photoreactor uses a photoreactor equipped with a reflux condenser, so that the volatilized 2,2-dichlorohexafluoropropane and organic solvent can be recovered into the photoreactor to continue the reaction during the reaction.
[0035] Step 2) The mixture obtained in step 1) is vigorously stirred under magnetic stirring conditions to make the photocatalyst suspended in the solution to obtain a suspension.
[0036] Step 3) Irradiating the suspension with a light source and introducing oxygen to react at room temperature.
[0037] The light source is one of a xenon lamp, a mercury lamp, an LED lamp and sunlight.
[0038] Furthermore, in order to promote the smooth reaction of 2,2-dichlorohexafluoropropane and oxygen in the suspension under light, the power of the light source is controlled at 100-300W.
[0039] Among them, after oxygen is introduced into the suspension, the following reaction occurs at room temperature under the conditions of photocatalysis and light:
[0040]
[0041] Furthermore, in order to allow oxygen to fully react with 2,2-dichlorohexafluoropropane in the suspension, an oxygen supply tube is inserted below the liquid surface of the suspension to pass oxygen into the suspension, and the oxygen flow rate is controlled by a gas flow meter to control the oxygen introduction rate to 0.5-1.5 L / h, and the reaction time is controlled to 5-24 h.
[0042] As a specific embodiment of the present invention, in order to achieve the best reaction effect between oxygen and 2,2-dichlorohexafluoropropane in the suspension, the oxygen introduction rate is controlled to be 1 L / h.
[0043] Step 4) The tail gas generated during the reaction of oxygen and 2,2-dichlorohexafluoropropane is passed into water for absorption.
[0044] The tail gas generated during the reaction contains hexafluoroacetone gas, chlorine oxides, and oxygen and 2,2-dichlorohexafluoropropane that are carried away with the tail gas before they have time to fully react.
[0045] Furthermore, in order to prevent the liquid from being sucked back in the photoreactor when the tail gas is absorbed in the water, the tail gas is first passed into the anti-back-suction bottle, and then the tail gas is passed through the air pipe into the water storage bottle connected to the air pipe of the anti-back-suction bottle.
[0046] At the same time, in order to allow the tail gas to be fully absorbed by water, the liquid is continuously stirred by magnetic force during the process of the tail gas being passed into the water.
[0047] Step 5) In order to separate hexafluoroacetone from the tail gas, after the reaction between oxygen and 2,2-dichlorohexafluoropropane is completed, the tail gas absorption liquid is distilled at normal pressure to obtain hexafluoroacetone trihydrate.
[0048] Specifically, after the reaction of oxygen and 2,2-dichlorohexafluoropropane is completed, the tail gas absorption liquid in the water storage bottle is poured into the glass three-necked flask, and the tail gas absorption liquid in the glass three-necked flask is heated by oil bath heating, and the oil bath temperature is controlled at 110-140°C.
[0049] Since the boiling point of hexafluoroacetone trihydrate is 105-106°C, hexafluoroacetone trihydrate can be obtained by collecting the fraction at 105-106°C during the distillation of the tail gas absorption liquid in an oil bath under normal pressure.
[0050] The invention provides a method for preparing hexafluoroacetone trihydrate, wherein the reaction conditions in the preparation process are mild and easy to control, the preparation cost is low, and the process is economical and efficient. In addition, the raw material 2,2-dichlorohexafluoropropane is easy to prepare, the cost is low, and the process is economical and efficient. At the same time, the invention uses a metal oxide semiconductor material as a photocatalyst, and the purity and yield of the hexafluoroacetone trihydrate finally prepared are both high.
[0051] Therefore, the method for preparing hexafluoroacetone trihydrate provided by the present invention not only has high preparation efficiency, low cost and good economic benefits, but also has high product purity and high yield, has broad application prospects, and is worthy of popularization and application.
[0052] The following is a detailed description of the preparation method of hexafluoroacetone trihydrate provided by the present invention through examples.
[0053] Example 1
[0054] TiO2 and 2,2-dichlorohexafluoropropane were added into a photoreactor equipped with a reflux condenser in a molar ratio of 1:10, DMF was added in an amount 5 times the mass of the raw material, magnetic stirring was started, a 300W xenon lamp light source was used to irradiate the reaction system, oxygen was introduced at a rate of 1L / h, the reaction was carried out at room temperature, the tail gas was absorbed in water, the reaction was stopped after 10h, the tail gas absorption liquid was distilled at atmospheric pressure, and the fraction at 105-106°C was collected to obtain hexafluoroacetone trihydrate with a purity of 99.5% and a yield of 86.3% as determined by GC.
[0055] Example 2
[0056] ZnO and 2,2-dichlorohexafluoropropane were added into a photoreactor equipped with a reflux condenser at a molar ratio of 1:10, DMF of 5 times the mass of the raw material was added, magnetic stirring was started, a 300W xenon lamp light source was used to irradiate the reaction system, oxygen was introduced at a rate of 1L / h, the reaction was carried out at room temperature, the tail gas was absorbed in water, the reaction was stopped after 10h, the tail gas absorption liquid was distilled at atmospheric pressure, and the fraction at 105-106°C was collected to obtain hexafluoroacetone trihydrate, with a purity of 99.2% and a yield of 72.8% detected by GC.
[0057] Example 3
[0058] WO3 and 2,2-dichlorohexafluoropropane were added into a photoreactor equipped with a reflux condenser in a molar ratio of 1:10, DMF was added in an amount 5 times the mass of the raw material, magnetic stirring was started, a 300W xenon lamp light source was used to irradiate the reaction system, oxygen was introduced at a rate of 1L / h, the reaction was carried out at room temperature, the tail gas was absorbed in water, the reaction was stopped after 10h, the tail gas absorption liquid was distilled at atmospheric pressure, and the fraction at 105-106°C was collected to obtain hexafluoroacetone trihydrate, the purity of which was 99.2% by GC detection, and the yield was 78.5%.
[0059] Example 4
[0060] TiO2 and 2,2-dichlorohexafluoropropane were added into a photoreactor equipped with a reflux condenser in a molar ratio of 1:100, DMF was added in an amount 5 times the mass of the raw material, magnetic stirring was started, a 300W xenon lamp light source was used to irradiate the reaction system, oxygen was introduced at a rate of 1L / h, the reaction was carried out at room temperature, the tail gas was absorbed in water, the reaction was stopped after 15h, the tail gas absorption liquid was distilled at atmospheric pressure, and the fraction at 105-106°C was collected to obtain hexafluoroacetone trihydrate, the purity of which was 99.3% by GC detection, and the yield was 75.6%.
[0061] Example 5
[0062] TiO2 and 2,2-dichlorohexafluoropropane were added into a photoreactor equipped with a reflux condenser at a molar ratio of 1:10, DMF was added in an amount 5 times the mass of the raw material, magnetic stirring was started, a 100W xenon lamp light source was used to irradiate the reaction system, oxygen was introduced at a rate of 1L / h, the reaction was carried out at room temperature, the tail gas was absorbed in water, the reaction was stopped after 10h, the tail gas absorption liquid was distilled at atmospheric pressure, and the fraction at 105-106°C was collected to obtain hexafluoroacetone trihydrate, the purity of which was 99.5% as determined by GC, and the yield was 72.6%.
[0063] Example 6
[0064] TiO2 and 2,2-dichlorohexafluoropropane were added into a photoreactor equipped with a reflux condenser in a molar ratio of 1:100, DMF was added in an amount 5 times the mass of the raw material, magnetic stirring was started, the reaction system was irradiated with a 100 W LED light source, oxygen was introduced at a rate of 1 L / h, the reaction was carried out at room temperature, the tail gas was absorbed in water, the reaction was stopped after 24 hours, the tail gas absorption liquid was distilled at atmospheric pressure, and the fraction at 105-106°C was collected to obtain hexafluoroacetone trihydrate with a purity of 98.9% and a yield of 33.4% as determined by GC.
[0065] Example 7
[0066] TiO2 and 2,2-dichlorohexafluoropropane were added into a photoreactor equipped with a reflux condenser at a molar ratio of 1:10, acetonitrile was added in an amount of 5 times the mass of the raw material, magnetic stirring was started, a 300W xenon lamp light source was used to irradiate the reaction system, oxygen was introduced at a rate of 1L / h, the reaction was carried out at room temperature, the tail gas was absorbed in water, the reaction was stopped after 10h, the tail gas absorption liquid was distilled at atmospheric pressure, the fraction at 105-106°C was collected, and hexafluoroacetone trihydrate was obtained. The purity detected by GC was 99.6%, and the yield was 81.9%.
[0067] Comparative Example
[0068] Compared with Example 1, in this comparative example, no catalyst was added, 2,2-dichlorohexafluoropropane was added to a photoreactor equipped with a reflux condenser, DMF of 5 times the mass of the raw material was added, magnetic stirring was turned on, the reaction system was irradiated with a 300W xenon lamp light source, oxygen was introduced at a rate of 1L / h, the reaction was carried out at room temperature, the tail gas was absorbed in water, the reaction was stopped after 10h, the tail gas absorption liquid was distilled at atmospheric pressure, and the fraction at 105-106°C was collected to obtain hexafluoroacetone trihydrate, the purity of which was 99.1% by GC detection, and the yield was 24.7%.
[0069] From the comparison of the purity and yield of the hexafluoroacetone trihydrate prepared in Examples 1-7 of the present invention and the comparative example, it can be seen that the method for preparing hexafluoroacetone trihydrate provided by the embodiment of the present invention uses a metal oxide semiconductor material as a photocatalyst, and the hexafluoroacetone trihydrate finally prepared has not only high purity but also relatively high yield. The purity of the obtained hexafluoroacetone trihydrate is above 98%, and the yield is above 72%.
[0070] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.
Claims
1. A method for preparing hexafluoroacetone trihydrate, characterized in that: The steps include: Mixing 2,2-dichlorohexafluoropropane, an organic solvent and a metal oxide serving as a photocatalyst in a photoreactor; The mixture is stirred until the photocatalyst is in a suspended state to obtain a suspension; Irradiate the suspension with a light source and introduce oxygen to react at room temperature; The tail gas produced by the reaction is passed into water for absorption; The tail gas absorption liquid is distilled at normal pressure to obtain hexafluoroacetone trihydrate.
2. The method for preparing hexafluoroacetone trihydrate according to claim 1, characterized in that: The photocatalyst is one of TiO2, ZnO, Fe2O3, ZrO2, SnO2, and WO3.
3. The method for preparing hexafluoroacetone trihydrate according to claim 2, characterized in that: The molar ratio of the photocatalyst to 2,2-dichlorohexafluoropropane is 1:10 to 1:
100.
4. The method for preparing hexafluoroacetone trihydrate according to claim 1, characterized in that: The organic solvent is one of dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, hexamethylphosphoric triamide, acetonitrile and tetrahydrofuran.
5. The method for preparing hexafluoroacetone trihydrate according to claim 4, characterized in that: The mass ratio of the organic solvent to 2,2-dichlorohexafluoropropane is 10:1 to 1:
1.
6. The method for preparing hexafluoroacetone trihydrate according to claim 1, characterized in that: The light source is one of a xenon lamp, a mercury lamp, an LED lamp and sunlight.
7. The method for preparing hexafluoroacetone trihydrate according to claim 6, characterized in that: The power of the light source is 100-300W.
8. The method for preparing hexafluoroacetone trihydrate according to claim 1, characterized in that: The oxygen introduction rate is 0.5 to 1.5 L / h.
9. The method for preparing hexafluoroacetone trihydrate according to claim 8, characterized in that: The reaction time at room temperature is 5 to 24 hours.
10. The method for preparing hexafluoroacetone trihydrate according to claim 1, characterized in that: The tail gas absorption liquid is subjected to atmospheric distillation and the fraction at 105-106° C. is collected to obtain hexafluoroacetone trihydrate.