Synthesis method of low-cost perfluorohexanone
Through the alkylation reaction of perfluoropentane iodide and hexafluoropropylene and the epoxidation-isomerization reaction of metal porphyrin catalyst, the problems of low selectivity and yield in the synthesis of perfluorohexanone were solved, and low-cost and efficient perfluorohexanone production was achieved.
Patent Information
- Application Number
- CN202510720059.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-30
- Publication Date
- 2025-09-16
AI Technical Summary
Existing perfluorohexanone synthesis methods have problems such as poor selectivity, low yield, low catalyst efficiency, harsh reaction conditions or difficulty in obtaining raw materials, resulting in high production costs.
The alkylation reaction of perfluoropentane iodide and hexafluoropropylene is combined with the epoxidation-isomerization reaction of metal porphyrin catalyst in a continuous flow microchannel reactor, using a phase transfer catalyst and mild reaction conditions to produce high-purity perfluorohexanone.
The highly selective and high-yield synthesis of perfluorohexanone was achieved, which reduced the waste of raw materials and catalyst consumption costs, improved the reaction safety and equipment life, and reduced the need for subsequent purification steps.
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Figure CN120647513A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of perfluorohexanone synthesis, and in particular to a low-cost method for synthesizing perfluorohexanone. Background Art
[0002] Perfluorohexanone (C6F 12 O) is a fluorinated compound with excellent physical and chemical properties. All hydrogen atoms in its molecular structure are replaced by fluorine atoms, imparting exceptional chemical and thermal stability. This compound exhibits extremely low surface tension, good material compatibility, and excellent fire extinguishing efficiency (cup burner extinguishing concentration ≤ 4.5%), complying with environmental regulations. It is an ideal alternative to halon fire extinguishing agents and is widely used in electrochemical energy storage systems as a mainstream fire extinguishing agent in live environments.
[0003] There are various methods for synthesizing perfluorohexanone. The current mainstream methods include the hexafluoropropylene oxidation process, the dimer epoxidation rearrangement process, and the 3M process. The hexafluoropropylene oxidation process suffers from poor selectivity and low yield; the dimer epoxidation rearrangement process faces the problems of many polymerization by-products and low purity; and although the 3M process has good yield and selectivity, the intermediate perfluoropropionyl fluoride is difficult to prepare. In addition, there are perfluoroolefin epoxidation isomerization methods and catalytic reaction methods of hexafluoropropylene and hexafluoropropylene oxide, but these methods often suffer from low catalyst efficiency, harsh reaction conditions, or difficult to obtain raw materials. Summary of the Invention
[0004] The technical problem to be solved by the present invention is how to synthesize perfluorohexanone at low cost.
[0005] The present invention solves the above technical problems through the following technical means:
[0006] The present invention provides a low-cost synthesis method of perfluorohexanone, comprising the following steps:
[0007] S1 Alkylation reaction: Perfluoropentane iodide and hexafluoropropylene are reacted under an inert gas atmosphere with the addition of an initiator and a phase transfer catalyst to obtain a perfluoroalkane C8F 16 ;
[0008] S2 epoxidation-isomerization reaction: perfluoroalkane C8F 16 It is introduced into a continuous flow microchannel reactor with hydrogen peroxide and reacted with a metal porphyrin catalyst to generate perfluorohexanone C6F 12 O.
[0009] Beneficial Effects: The present invention enables the synthesis of perfluorohexanone with high selectivity and high yield through a two-step reaction. This synthetic route avoids the low selectivity and low yield problems of traditional methods, thereby reducing raw material waste and subsequent purification costs, thereby lowering synthesis costs. The metalloporphyrin catalyst used in the present invention can be recycled and reused, further reducing catalyst consumption costs.
[0010] In the case of an initiator, hexafluoropropylene first undergoes an addition reaction to generate a free radical intermediate, which then undergoes a substitution reaction with perfluoropentane iodide, causing the iodine atom to be replaced by a fluoroalkyl group to generate a perfluoroalkane C8F 16 In step S1, the fluoroalkyl group is transferred from perfluoropentane iodide to hexafluoropropylene through the transfer and growth of free radicals, thereby generating perfluoroalkane C8F 16 ; The use of phase transfer catalyst in S1 helps to stabilize free radical intermediates, promote the reaction, and affect the mode and rate of chain termination.
[0011] In step S2, hydrogen peroxide is used as an oxidant to oxidize perfluoroalkane C8F under the action of metalloporphyrin catalyst. 16 The carbon-carbon double bond in the epoxide is oxidized to generate an epoxide intermediate, which further undergoes an isomerization reaction to generate perfluorohexanone C6F 12 The present invention utilizes a metalloporphyrin catalyst to convert an alkane structure into perfluorohexanone. The reaction is carried out in a continuous flow microchannel reactor, which offers the advantages of mild reaction conditions, high mass and heat transfer efficiency, and easy control. This helps reduce side reactions and improves product purity and yield, thereby achieving low-cost synthesis of perfluorohexanone.
[0012] Preferably, the molar ratio of perfluoropentyl iodide to hexafluoropropylene is 1:1 to 1.5.
[0013] Preferably, the molar ratio of the initiator to hexafluoropropylene is 1:50-100, and the initiator is benzoyl peroxide.
[0014] Preferably, the molar ratio of the phase transfer catalyst to the initiator is 0.5 to 1:1, and the phase transfer catalyst is 18-crown-6.
[0015] Preferably, the reaction temperature in S1 is 40-60° C., and the reaction time is 8-12 h.
[0016] Preferably, the hydrogen peroxide and perfluoroalkane C8F 16 The molar ratio is 2 to 3:1.
[0017] Preferably, the metalloporphyrin catalyst is prepared according to the following method:
[0018] The metal porphyrin is dissolved in an organic solvent to prepare a solution, into which dry mesoporous silica SBA-15 is added, and the solution is stirred, centrifuged, washed and dried to obtain the metal porphyrin catalyst.
[0019] Beneficial effects: The metalloporphyrin catalyst of the present invention can be recycled after the reaction and can be reused more than 5 times, and its catalytic activity can still be maintained at more than 92% of the initial activity.
[0020] Preferably, the mass ratio of the metal porphyrin to the mesoporous silica SBA-15 is 1:5-10.
[0021] Preferably, the metalloporphyrin is an iron or manganese porphyrin complex.
[0022] Preferably, the reaction temperature in S2 is 50-70° C., and the reaction pressure is 2-3 MPa.
[0023] Preferably, perfluorohexanone C6F 12 After distillation and vacuum distillation, high-purity perfluorohexanone C6F 12 O.
[0024] Preferably, the conditions for the vacuum distillation are a boiling point of 48 to 50° C. and a vacuum degree of 0.096 to 0.1 MPa.
[0025] Compared with the prior art, the present invention has the following advantages:
[0026] Efficient Synthesis Pathway: The present invention utilizes an alkylation reaction and epoxidation-isomerization reaction of perfluoropentane iodide with hexafluoropropylene. Through precise control of reaction conditions and catalyst usage, perfluorohexanone can be synthesized with high selectivity and high yield. This synthesis path avoids the low selectivity and low yield associated with traditional methods, thereby reducing raw material waste and subsequent purification costs.
[0027] Catalyst reusability: The metalloporphyrin catalyst used in this invention can be recycled and reused multiple times after the reaction. Even after five consecutive uses, the catalyst's catalytic activity can still maintain over 92% of its initial activity, significantly reducing catalyst consumption costs.
[0028] Mild reaction conditions: This invention utilizes a continuous flow microchannel reactor to conduct the reaction, achieving mild reaction conditions and using lower temperatures and pressures. This not only improves reaction safety but also reduces energy consumption and equipment investment. Mild reaction conditions help extend equipment life, reduce maintenance costs, and minimize side reactions and product degradation caused by high temperature and pressure.
[0029] High-purity product reduces subsequent processing costs: By precisely controlling reaction conditions and optimizing purification steps (such as distillation and vacuum distillation), the present invention can produce perfluorohexanone with a purity of no less than 99.5%. This high-purity product reduces the need for subsequent processing (such as further purification or impurity removal), thereby reducing overall production costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Figure 1 It is a structural schematic diagram of a continuous flow microchannel reactor;
[0031] Figure 2 is the perfluoroalkane C8F in Example 1 16 Infrared spectrum of
[0032] Figure 3 is the perfluoroalkane C8F in Example 1 16 fluorine NMR spectrum;
[0033] Figure 4 This is the gas chromatograph detection result of perfluorohexanone in Example 1. DETAILED DESCRIPTION
[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.
[0035] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.
[0036] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the field or according to the product instructions.
[0037] Example 1
[0038] This embodiment provides a low-cost synthesis method of perfluorohexanone, which specifically includes the following steps:
[0039] S1 alkylation reaction:
[0040] Perfluoropentane iodide was dissolved in anhydrous acetonitrile to obtain solution A, wherein the ratio of anhydrous acetonitrile to perfluoropentane iodide was 15 ml:1 g. Hexafluoropropylene was slowly added to solution A, wherein the molar ratio of hexafluoropropylene to perfluoropentane was 1:1. During the addition of hexafluoropropylene, the solution was added in small amounts and multiple times to avoid local overheating of solution A.
[0041] Then, 5% by mass of benzoyl peroxide was added under a nitrogen atmosphere, wherein the molar ratio of the benzoyl peroxide to hexafluoropropylene was 1:50, and then 18-crown-6 was added, wherein the molar ratio of the 18-crown-6 to benzoyl peroxide was 0.5:1.
[0042] The mixture was heated to 40°C in a water bath and stirred for 8 hours. After the reaction, the excess solvent was removed by pressure distillation to obtain a crude product of perfluoroalkane C8F 16 .
[0043] The perfluoroalkane C8F 16 The infrared spectrum and nuclear magnetic resonance fluorine spectrum of Figure 2-3 As shown, according to Figure 2 It can be seen that in 600-1400cm -1 A strong absorption peak appears in the range of perfluoroalkane C8F 16 Typical regions of carbon-fluorine bond stretching vibrations due to perfluoroalkane C8F 16 The molecule contains multiple carbon-fluorine bonds, and the vibrations of these bonds are superimposed on each other to form multiple strong peaks. The appearance of strong peaks indicates that perfluoroalkane C8F 16 Generation.
[0044] The reaction equation is as follows:
[0045]
[0046] S2 epoxidation-isomerization reaction:
[0047] Perfluoroalkane C8F 16 Dissolve in anhydrous acetonitrile to obtain solution B, wherein the ratio of anhydrous acetonitrile to perfluoropentane iodide is 15 ml:1 g, and add hydrogen peroxide to obtain a mixture. 16 The molar ratio is 2:1.
[0048] The metalloporphyrin catalyst is prepared according to the following method: mesoporous silica SBA-15 is placed in a vacuum drying oven at 80° C. for drying and activation treatment to obtain dry mesoporous silica SBA-15.
[0049] Fe(TMPyP)Cl was dissolved in dimethyl sulfoxide to prepare a solution with a concentration of 0.5 g / L, and dry mesoporous silica SBA-15 was added thereto. The mass ratio of Fe(TMPyP)Cl to mesoporous silica SBA-15 was 1:5. The solution was stirred at room temperature for 18 hours to allow Fe(TMPyP)Cl to be fully adsorbed into the pores of the mesoporous silica SBA-15. The solution was then centrifuged, washed three times with anhydrous ethanol, and dried in vacuum at 60°C overnight to obtain a metalloporphyrin catalyst.
[0050] Then the metal porphyrin catalyst was added to the mixture and placed Figure 1 In the mixer shown, the reaction is carried out in a continuous flow microchannel reactor via a pump. The reaction temperature is 50° C. and the reaction pressure is 2 MPa.
[0051] After the reaction is completed, the solvent is removed by distillation, and then high-purity perfluorohexanone C6F is obtained by vacuum distillation. 12 O; the conditions for the vacuum distillation are a boiling point of 50°C and a vacuum degree of 0.1 MPa. The purity of the finally obtained perfluorohexanone is not less than 99.5%, and the yield reaches 88.5%.
[0052] The perfluorohexanone C6F 12 The gas chromatograph test results of O are as follows Figure 4 As shown in the figure, the peak time 6.918 is perfluorohexanone C6F 12 O.
[0053] The reaction equation is as follows:
[0054]
[0055] Example 2
[0056] This embodiment provides a low-cost synthesis method of perfluorohexanone. The difference between this embodiment and Example 1 is that the usage ratio of anhydrous acetonitrile to perfluoroiodopentane is 10 ml:1 g, and the molar ratio of hexafluoropropylene to perfluoroiodopentane is 1.5:1.
[0057] The purity of the finally obtained perfluorohexanone is not less than 99.5%, and the yield reaches 85.3%.
[0058] Example 3
[0059] This embodiment provides a low-cost method for synthesizing perfluorohexanone. The difference between this embodiment and Example 1 is that the molar ratio of the benzoyl peroxide to hexafluoropropylene is 1:100.
[0060] The purity of the finally obtained perfluorohexanone is not less than 99.5%, and the yield reaches 86.2%.
[0061] Example 4
[0062] This embodiment provides a low-cost synthesis method of perfluorohexanone. The difference between this embodiment and Example 1 is that the molar ratio of 18-crown-6 to benzoyl peroxide is 1:1.
[0063] The purity of the finally obtained perfluorohexanone is not less than 99.5%, and the yield reaches 88%.
[0064] Example 5
[0065] This embodiment provides a low-cost synthesis method of perfluorohexanone. The difference between this embodiment and embodiment 1 is that the ratio of anhydrous acetonitrile to perfluoropentane iodide is 10ml:1g; the ratio of hydrogen peroxide to perfluoroalkane C8F 16 The molar ratio is 3:1.
[0066] The purity of the finally obtained perfluorohexanone is not less than 99.5%, and the yield reaches 85.3%.
[0067] Example 6
[0068] This embodiment provides a low-cost synthesis method of perfluorohexanone. The difference between this embodiment and Example 1 is that the mass ratio of metalloporphyrin to mesoporous silica SBA-15 is 1:10.
[0069] The purity of the finally obtained perfluorohexanone is not less than 99.5%, and the yield reaches 85.3%.
[0070] Comparative Example 1
[0071] This comparative example provides a method for synthesizing perfluorohexanone. The difference between this comparative example and Example 1 is that the equipment used in step S2 is a high-pressure reactor, the reaction temperature is 50° C., and the reaction pressure is 2 MPa.
[0072] The purity of the finally obtained perfluorohexanone does not exceed 80%, and the yield is less than 60%.
[0073] High-pressure reactors have low mass and heat transfer efficiencies, leading to incomplete reactions or increased side reactions, which in turn reduces product purity and yield. The continuous flow microchannel reactor, with its unique structure, offers high mass and heat transfer efficiencies and ease of control. This allows for more effective reaction promotion, reduced side reactions, and improved product purity and yield.
[0074] Comparative Example 2
[0075] This comparative example provides a method for synthesizing perfluorohexanone. The difference between this comparative example and Example 1 is that no metalloporphyrin catalyst is used in step S2, and other reaction conditions are consistent with Example 1.
[0076] The purity of the finally obtained perfluorohexanone was 75%, and the yield was less than 50%.
[0077] It can be seen that the metal porphyrin catalyst plays a key role in the synthesis of perfluorohexanone. Its absence leads to a significant decrease in reaction efficiency, and a significant decrease in product purity and yield.
[0078] Comparative Example 3
[0079] This comparative example provides a method for synthesizing perfluorohexanone. The difference between this comparative example and Example 1 is that in the S1 alkylation reaction, the phase transfer catalyst 18-crown-6 is not used, and the other reaction conditions are consistent with Example 1.
[0080] The purity of the finally obtained perfluorohexanone was 82% and the yield was 55%.
[0081] Compared with Example 1, the absence of a phase transfer catalyst in this comparative example leads to a decrease in the stability of free radicals during the reaction and an acceleration of the chain termination rate, thereby affecting the performance of the perfluoroalkane C8F 16 The production efficiency of perfluorohexanone is affected, which in turn affects the final yield and purity of perfluorohexanone.
[0082] Experimental example
[0083] The metalloporphyrin catalyst used in Example 1 was recovered and separated from the reaction mixture by centrifugation. Subsequently, the metalloporphyrin catalyst was washed multiple times with anhydrous ethanol to remove surface-adsorbed impurities and residual reactants. Finally, the metalloporphyrin catalyst was dried overnight in a vacuum drying oven at 60° C. to obtain a recovered metalloporphyrin catalyst.
[0084] Catalyst reuse times and activity retention:
[0085] The experimental results show that after five consecutive uses, the catalytic activity of the metalloporphyrin catalyst can still be maintained at more than 92% of the initial activity (with the yield of perfluorohexanone as the evaluation index). The specific data are as follows:
[0086] First use: The yield of perfluorohexanone was 88.5%.
[0087] Second use: The yield of perfluorohexanone was 87.2%.
[0088] The third use: the yield of perfluorohexanone was 86.8%.
[0089] Fourth use: The yield of perfluorohexanone was 86.0%.
[0090] The fifth use: the yield of perfluorohexanone was 85.1%.
[0091] This data shows that the metal porphyrin catalyst can still maintain a high catalytic activity after multiple uses, effectively reducing the catalyst consumption cost.
[0092] Impact of catalyst reuse on costs:
[0093] The cost of the metalloporphyrin catalyst accounts for 20% of the total synthesis cost. Reusing the metalloporphyrin catalyst can significantly reduce costs. For example, when the metalloporphyrin catalyst is used five times in a row, the average catalyst cost per reaction is only about 4% of the original cost. This means that reusing the metalloporphyrin catalyst can significantly reduce the cost of perfluorohexanone synthesis.
[0094] The present invention not only achieves efficient synthesis of perfluorohexanone by the following technical means, but also significantly reduces production costs, which is mainly reflected in the following aspects:
[0095] Efficient Synthesis Pathway: The present invention utilizes an alkylation reaction and epoxidation-isomerization reaction of perfluoropentane iodide with hexafluoropropylene. Through precise control of reaction conditions and catalyst usage, perfluorohexanone can be synthesized with high selectivity and high yield. This synthesis path avoids the low selectivity and low yield associated with traditional methods, thereby reducing raw material waste and subsequent purification costs.
[0096] Catalyst Reusability: The metalloporphyrin catalyst used in this invention can be recovered after the reaction by simple centrifugation, washing, and drying, and can be reused multiple times. Experimental data shows that after five consecutive uses, the catalyst's catalytic activity remains above 92% of its initial activity, significantly reducing catalyst consumption costs.
[0097] Mild reaction conditions: This invention utilizes a continuous flow microchannel reactor to conduct the reaction, achieving mild reaction conditions and using lower temperatures and pressures. This not only improves reaction safety but also reduces energy consumption and equipment investment. Mild reaction conditions help extend equipment life, reduce maintenance costs, and minimize side reactions and product degradation caused by high temperature and pressure.
[0098] High-purity product reduces subsequent processing costs: By precisely controlling reaction conditions and optimizing purification steps (such as distillation and vacuum distillation), the present invention can produce perfluorohexanone with a purity of no less than 99.5%. This high-purity product reduces the need for subsequent processing (such as further purification or impurity removal), thereby reducing overall production costs.
[0099] In summary, the present invention achieves low-cost synthesis of perfluorohexanone through an efficient synthesis route, reusability of the catalyst, mild reaction conditions, and acquisition of high-purity products.
[0100] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.
Claims
1. A low-cost synthesis method of perfluorohexanone, characterized in that: The following steps are involved: S1 Alkylation reaction: Perfluoropentane iodide and hexafluoropropylene are reacted under an inert gas atmosphere with the addition of an initiator and a phase transfer catalyst to obtain a perfluoroalkane C8F 16 ; S2 epoxidation-isomerization reaction: perfluoroalkane C8F 16 It is introduced into a continuous flow microchannel reactor with hydrogen peroxide and reacted with a metal porphyrin catalyst to generate perfluorohexanone C6F 12 O.
2. The method for synthesizing low-cost perfluorohexanone according to claim 1, characterized in that: The molar ratio of the perfluoropentyl iodide to hexafluoropropylene is 1:1 to 1.
5.
3. The method for synthesizing low-cost perfluorohexanone according to claim 1, characterized in that: The molar ratio of the initiator to hexafluoropropylene is 1:50-100, and the initiator is benzoyl peroxide.
4. The method for synthesizing low-cost perfluorohexanone according to claim 1, characterized in that: The molar ratio of the phase transfer catalyst to the initiator is 0.5 to 1:1, and the phase transfer catalyst is 18-crown-6.
5. The method for synthesizing low-cost perfluorohexanone according to claim 1, characterized in that: The reaction temperature in S1 is 40-60°C, and the reaction time is 8-12 hours.
6. The method for synthesizing low-cost perfluorohexanone according to claim 1, characterized in that: The hydrogen peroxide and perfluoroalkane C8F 16 The molar ratio is 2 to 3:
1.
7. The method for synthesizing low-cost perfluorohexanone according to claim 1, characterized in that: The metalloporphyrin catalyst is prepared according to the following method: The metalloporphyrin is dissolved in an organic solvent to prepare a solution, dry mesoporous silica SBA-15 is added thereto, and the solution is stirred, centrifuged, washed, and dried to obtain a metalloporphyrin catalyst; The mass ratio of metal porphyrin to mesoporous silica SBA-15 is 1:5-10.
8. The method for synthesizing low-cost perfluorohexanone according to claim 7, characterized in that: The metal porphyrin is an iron or manganese porphyrin complex.
9. The method for synthesizing low-cost perfluorohexanone according to claim 1, characterized in that: The reaction temperature in S2 is 50-70°C, and the reaction pressure is 2-3 MPa.
10. The method for synthesizing low-cost perfluorohexanone according to claim 1, characterized in that: Perfluorohexanone C6F 12 After distillation and vacuum distillation, high-purity perfluorohexanone C6F 12 O.