Production process of hexafluoropropylene oxide trimer
By using fixed bed reaction and impregnation method to load molecular sieves in the hexafluoropropylene oxide trimer production process, the problems of low yield and high production cost of the existing process are solved, and efficient and low-cost trimer preparation is achieved.
Patent Information
- Application Number
- CN202410516678.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-28
- Publication Date
- 2025-01-21
- Estimated Expiration
- 2044-04-28
AI Technical Summary
The existing production process of hexafluoropropylene oxide trimers has low yields, many by-products are produced, complex processes and requires a large number of solvents, resulting in high production costs.
Using a fixed-bed reaction process, fluoride salts and fluorine-containing quaternary ammonium salts are loaded on the SBA-15 molecular sieve through the impregnation method, and the space velocity ratio of nitrogen and hexafluoropropylene oxide and the filling length of the molecular sieve are controlled to achieve efficient trimer Preparation, avoid using solvents.
The yield of hexafluoropropylene oxide trimer is increased, the generation of by-products is reduced, the process flow is simplified, the production cost is reduced, and the ability to directionally prepare HFPO trimer is achieved.
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Figure CN118388338B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of fluorine chemical industry, and in particular to a production process of hexafluoropropylene oxide trimer. Background Art
[0002] Hexafluoropropylene oxide trimer is prepared by the polymerization of hexafluoropropylene oxide. It is a colorless and transparent liquid at room temperature and pressure, and its corresponding carboxylic acid has high surface activity. With the ban on the use of PFOA, surfactants using hexafluoropropylene oxide trimer as raw material can replace PFOA. In the PTFE polymerization process, the ammonium salt corresponding to the carboxylic acid of hexafluoropropylene oxide trimer can well replace the use of PFOA. By introducing different groups into the terminal groups of hexafluoropropylene oxide trimer, surfactants with different functions can be prepared. The corresponding fluorinated vinyl ether is prepared by treating the terminal groups of hexafluoropropylene oxide trimer, which can be used in fluoroelastomers with a glass transition temperature below -10°C.
[0003] The existing process has low yield and generates more by-product dimers or tetramers. The production process is complicated and uses more solvents, which requires subsequent distillation treatment, increasing production costs. Summary of the invention
[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a production process for hexafluoropropylene oxide trimer, which adopts a fixed bed reaction, has a high trimer yield, does not involve the use of solvents, has a high content of the product after the reaction, and has a low production cost.
[0005] The production process of the hexafluoropropylene oxide trimer of the present invention comprises the following steps:
[0006] (1) Preparation of molecular sieves by impregnation method:
[0007] The SBA-15 molecular sieve is loaded by vacuum impregnation in a fluoride salt and a fluorine-containing quaternary ammonium salt aqueous solution, and the loaded molecular sieve is transferred to a vacuum drying oven for drying;
[0008] (2) filling the dried molecular sieve in a fixed bed;
[0009] (3) The fixed bed is heated to 30-50°C, and the vaporized hexafluoropropylene oxide and nitrogen are introduced from the upper part of the fixed bed for reaction. The finished clear liquid obtained by the reaction flows out from the lower part and is collected in a receiving tank after condensation. The specific fixed bed production process is shown in the figure below. Figure 1 shown.
[0010] The immersion time in step (1) is 2-4 hours.
[0011] The drying temperature in step (1) is 80° C. and the drying time is 24 hours.
[0012] The loading amount of the fluoride salt and the fluorine-containing quaternary ammonium salt on the SBA-15 molecular sieve in step (1) is 5%-12%.
[0013] The filling length of the molecular sieve in the fixed bed described in step (2) is 1.2-2m.
[0014] The flow rate of hexafluoropropylene oxide in step (3) is 12-30 g / min, the flow rate of nitrogen is 20-50 g / min, and the space velocity ratio of nitrogen to hexafluoropropylene oxide is 1.8-3.
[0015] The reaction time of the reaction described in step (3) is 2-4h.
[0016] The fluoride salt described in step (1) is one or more of lithium fluoride, potassium fluoride, sodium fluoride, cesium fluoride, sodium bifluoride, and potassium bifluoride, preferably potassium fluoride.
[0017] The fluorine-containing quaternary ammonium salt in step (1) is one or more of tetrabutylammonium fluoride, tetraethylammonium fluoride, tetramethylammonium fluoride and tetrabutylammonium difluoride, preferably tetramethylammonium fluoride.
[0018] The molar ratio of the fluoride salt to the fluorine-containing quaternary ammonium salt in step (1) is 1:0.05-0.8, preferably 1:0.1-0.2.
[0019] Compared with the prior art, the present invention has the following beneficial effects:
[0020] 1) The production process of hexafluoropropylene oxide trimer of the present invention adopts a fixed bed reaction, has a high trimer yield, does not involve the use of solvents, has a high content of the product after the reaction, and has a low production cost.
[0021] 2) The present invention adopts a fixed bed production method to control the reaction process of hexafluoropropylene oxide. The space velocity ratio of nitrogen to hexafluoropropylene oxide and the amount of fluoride salt and fluorine-containing quaternary ammonium salt loaded by the molecular sieve control the addition reaction of hexafluoropropylene oxide. The product discharge position is controlled according to the filling length of the molecular sieve in the fixed bed, and HFPO trimer can be prepared in a directional manner.
[0022] 3) When the trimer is generated by reaction in a fixed bed, the hexafluoropropylene oxide raw material no longer contacts the trimer, so the directional selectivity of the trimer is high, thereby effectively improving the yield, and the reaction device can be operated efficiently and continuously, greatly improving the production capacity of the hexafluoropropylene oxide trimer. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 It is a schematic diagram of the fixed bed production process of the present invention.
[0024] Figure 2 This is the gas chromatogram of Example 2 of the present invention. DETAILED DESCRIPTION
[0025] The present invention is further described below in conjunction with embodiments, but the protection scope of the present invention is not limited thereto.
[0026] Unless otherwise specified, all raw materials used in the examples are commercially available.
[0027] Example 1
[0028] The production process of the hexafluoropropylene oxide trimer comprises the following steps:
[0029] (1) Preparation of molecular sieves by impregnation method:
[0030] The SBA-15 molecular sieve was vacuum impregnated in a 30 wt.% aqueous solution of potassium fluoride and tetrabutylammonium difluoride with a molar ratio of 1:0.1 for 2 h, and the loaded molecular sieve was transferred to a vacuum drying oven at 80°C for 24 h, with a loading amount of 5%;
[0031] (2) Filling the dried molecular sieve in a fixed bed; the filling length of the molecular sieve in the fixed bed is 1.2 m;
[0032] (3) The fixed bed is heated to 30° C., and vaporized hexafluoropropylene oxide is introduced from the upper part of the fixed bed at a flow rate of 22 g / min. Nitrogen is introduced from the upper part of the fixed bed at a flow rate of 40 g / min. The space velocity ratio of nitrogen to hexafluoropropylene oxide is 1.8. The nitrogen is introduced continuously for 4 hours to react. The finished clear liquid obtained by the reaction flows out from the lower part and is collected in a receiving tank after condensation.
[0033] The GC content showed that the dimer content was 13.1%, the trimer content was 85.5%, and the tetramer content was 1.4%.
[0034] Distillation step: distill the liquid in the receiving tank at 0.09-0.11 MPa, collect the fraction at 113-115°C, and measure its purity to be 99.6%.
[0035] Example 2
[0036] The production process of the hexafluoropropylene oxide trimer comprises the following steps:
[0037] (1) Preparation of molecular sieves by impregnation method:
[0038] The SBA-15 molecular sieve was vacuum impregnated in a 30 wt.% aqueous solution of sodium fluoride and tetramethylammonium fluoride at a molar ratio of 1:0.2 for loading for 3 h, and the loaded molecular sieve was transferred to a vacuum drying oven at 80°C for drying for 24 h, with a loading amount of 8.5%;
[0039] (2) Filling the dried molecular sieve in a fixed bed; the filling length of the molecular sieve in the fixed bed is 1.6 m;
[0040] (3) The fixed bed is heated to 40° C., and vaporized hexafluoropropylene oxide is introduced from the upper part of the fixed bed at a flow rate of 12 g / min. Nitrogen is introduced from the upper part of the fixed bed at a flow rate of 30 g / min. The space velocity ratio of nitrogen to hexafluoropropylene oxide is 2.5. The nitrogen is introduced continuously for 3 hours to react. The finished clear liquid obtained by the reaction flows out from the lower part and is collected in a receiving tank after condensation.
[0041] The GC content showed that the dimer content was 5.6%, the trimer content was 92.3%, and the tetramer content was 2.1%.
[0042] Distillation step: distill the liquid in the receiving tank at 0.09-0.11MPa, collect the fraction at 113-115°C, and measure its purity to be 99.9%. Its gas chromatogram is as follows: Figure 2 The result table is shown in Table 1 below;
[0043] Table 1 Gas chromatography results
[0044]
[0045]
[0046] Example 3
[0047] The production process of the hexafluoropropylene oxide trimer comprises the following steps:
[0048] (1) Preparation of molecular sieves by impregnation method:
[0049] The SBA-15 molecular sieve was vacuum impregnated in a 30 wt.% aqueous solution of potassium fluoride and tetrabutylammonium fluoride in a molar ratio of 1:0.1 for 4 hours, and the loaded molecular sieve was transferred to a vacuum drying oven at 80°C for 24 hours, and the loading amount was 12%;
[0050] (2) Filling the dried molecular sieve in a fixed bed; the filling length of the molecular sieve in the fixed bed is 2 m;
[0051] (3) The fixed bed is heated to 50° C., and vaporized hexafluoropropylene oxide is introduced from the upper part of the fixed bed at a flow rate of 17 g / min. Nitrogen is introduced from the upper part of the fixed bed at a flow rate of 50 g / min. The space velocity ratio of nitrogen to hexafluoropropylene oxide is 3. The nitrogen is introduced continuously for 2 hours to react. The finished clear liquid obtained by the reaction flows out from the lower part and is collected in a receiving tank after condensation.
[0052] The GC content showed that the dimer content was 2.3%, the trimer content was 84.1%, and the tetramer content was 13.6%.
[0053] Distillation step: distill the liquid in the receiving tank at 0.09-0.11 MPa, collect the fraction at 113-115°C, and measure its purity to be 99.5%.
[0054] Example 4
[0055] The production process of the hexafluoropropylene oxide trimer comprises the following steps:
[0056] (1) Preparation of molecular sieves by impregnation method:
[0057] The SBA-15 molecular sieve was vacuum impregnated in a 30 wt.% aqueous solution of potassium fluoride and tetrabutylammonium difluoride with a molar ratio of 1:0.3 for 2 h, and the loaded molecular sieve was transferred to a vacuum drying oven at 80°C for 24 h, with a loading amount of 5%;
[0058] (2) Filling the dried molecular sieve in a fixed bed; the filling length of the molecular sieve in the fixed bed is 1.2 m;
[0059] (3) The fixed bed is heated to 30° C., and vaporized hexafluoropropylene oxide is introduced from the upper part of the fixed bed at a flow rate of 22 g / min. Nitrogen is introduced from the upper part of the fixed bed at a flow rate of 40 g / min. The space velocity ratio of nitrogen to hexafluoropropylene oxide is 1.8. The nitrogen is introduced continuously for 4 hours to react. The finished clear liquid obtained by the reaction flows out from the lower part and is collected in a receiving tank after condensation.
[0060] The GC content showed that the dimer content was 0.5%, the trimer content was 75.0%, and the tetramer content was 24.5%.
[0061] Distillation step: distill the liquid in the receiving tank at 0.09-0.11 MPa, collect the fraction at 113-115°C, and measure its purity to be 99.3%.
[0062] Comparative Example 1
[0063] In a dry 10L stainless steel autoclave with a stirrer, 3L of tetraethylene glycol dimethyl ether and 200g of cesium fluoride were added respectively, stirred and mixed, and then 4kg of hexafluoropropylene oxide with a purity of 99.5% was introduced, and the temperature in the reactor was controlled at 0-10°C. The reactant temperature was maintained and stirred for 3h, and the reaction solution was cooled to -8°C and allowed to stand for stratification; the lower layer product was analyzed by GC, and the dimer content was 19.3%, the trimer content was 41.5%, the tetramer content was 29.6%, and the pentamer content was 9.6%. The lower layer product was distilled at a distillation temperature of 115°C and a pressure of 0.1MPa to obtain an adduct acyl fluoride product with a yield of 40% and a purity of 98.1%.
[0064] Comparative Example 2
[0065] The production process of hexafluoropropylene oxide trimer comprises the following steps:
[0066] (1) Preparation of molecular sieves by impregnation method:
[0067] The SBA-15 molecular sieve was vacuum impregnated in a 30 wt.% aqueous solution of sodium fluoride and tetramethylammonium fluoride at a molar ratio of 1:0.2 for loading for 3 h, and the loaded molecular sieve was transferred to a vacuum drying oven at 80°C for drying for 24 h, with a loading amount of 8.5%;
[0068] (2) Filling the dried molecular sieve in a fixed bed; the filling length of the molecular sieve in the fixed bed is 3 m;
[0069] (3) The fixed bed is heated to 40° C., and vaporized hexafluoropropylene oxide is introduced from the upper part of the fixed bed at a flow rate of 12 g / min. Nitrogen is introduced from the upper part of the fixed bed at a flow rate of 30 g / min. The space velocity ratio of nitrogen to hexafluoropropylene oxide is 2.5. The nitrogen is introduced continuously for 3 hours to react. The finished clear liquid obtained by the reaction flows out from the lower part and is collected in a receiving tank after condensation.
[0070] The content was determined by GC, with a dimer content of 3.1%, a trimer content of 64.2%, a tetramer content of 30.7%, and a pentamer content of 2.0%;
[0071] Distillation step: distill the liquid in the receiving tank at 0.09-0.11 MPa, collect the fraction at 113-115°C, and measure its purity to be 99.2%.
[0072] Comparative Example 3
[0073] The production process of hexafluoropropylene oxide trimer comprises the following steps:
[0074] (1) Preparation of molecular sieves by impregnation method:
[0075] The SBA-15 molecular sieve was vacuum impregnated in a 30 wt.% aqueous solution of sodium fluoride and tetramethylammonium fluoride at a molar ratio of 1:0.2 for loading for 3 h, and the loaded molecular sieve was transferred to a vacuum drying oven at 80°C for drying for 24 h, with a loading amount of 8.5%;
[0076] (2) Filling the dried molecular sieve in a fixed bed; the filling length of the molecular sieve in the fixed bed is 0.6 m;
[0077] (3) The fixed bed is heated to 40° C., and vaporized hexafluoropropylene oxide is introduced from the upper part of the fixed bed at a flow rate of 12 g / min. Nitrogen is introduced from the upper part of the fixed bed at a flow rate of 30 g / min. The space velocity ratio of nitrogen to hexafluoropropylene oxide is 2.5. The nitrogen is introduced continuously for 3 hours to react. The finished clear liquid obtained by the reaction flows out from the lower part and is collected in a receiving tank after condensation.
[0078] The GC content showed that the dimer content was 44.9%, the trimer content was 45.0%, and the tetramer content was 5.1%.
[0079] Distillation step: distill the liquid in the receiving tank at 0.09-0.11 MPa, collect the fraction at 113-115°C, and measure its purity to be 99.2%.
Claims
1. A production process for hexafluoropropylene oxide trimer, characterized in that: The following steps are involved: (1) Preparation of molecular sieves by impregnation method: The SBA-15 molecular sieve is loaded by vacuum impregnation in a fluoride salt and a fluorine-containing quaternary ammonium salt aqueous solution, and the loaded molecular sieve is transferred to a vacuum drying oven for drying; (2) Filling the dried molecular sieve into a fixed bed; (3) The fixed bed is heated to 30-50°C, and the vaporized hexafluoropropylene oxide and nitrogen are introduced from the upper part of the fixed bed for reaction. The finished clear liquid obtained by the reaction flows out from the lower part and is collected in a receiving tank after condensation; The filling length of the molecular sieve in the fixed bed in step (2) is 1.2-2 m; The molar ratio of the fluoride salt to the fluorine-containing quaternary ammonium salt in step (1) is 1:0.05-0.
8.
2. The production process of hexafluoropropylene oxide trimer according to claim 1, characterized in that: The immersion time in step (1) is 2-4 hours.
3. The production process of hexafluoropropylene oxide trimer according to claim 1, characterized in that: The drying temperature in step (1) is 80°C and the drying time is 24 hours.
4. The production process of hexafluoropropylene oxide trimer according to claim 1, characterized in that: The loading amount of the fluoride salt and the fluorine-containing quaternary ammonium salt on the SBA-15 molecular sieve in step (1) is 5%-12%.
5. The production process of hexafluoropropylene oxide trimer according to claim 1, characterized in that: The flow rate of hexafluoropropylene oxide in step (3) is 12-30 g / min, the flow rate of nitrogen is 20-50 g / min, and the space velocity ratio of nitrogen to hexafluoropropylene oxide is 1.8-3.
6. The production process of hexafluoropropylene oxide trimer according to claim 1, characterized in that: The reaction time of the reaction in step (3) is 2-4 hours.
7. The production process of hexafluoropropylene oxide trimer according to claim 1, characterized in that: The fluoride salt described in step (1) is one or more of lithium fluoride, potassium fluoride, sodium fluoride, cesium fluoride, sodium bifluoride, and potassium bifluoride.
8. The production process of hexafluoropropylene oxide trimer according to claim 1, characterized in that: The fluorine-containing quaternary ammonium salt in step (1) is one or more of tetrabutylammonium fluoride, tetraethylammonium fluoride, tetramethylammonium fluoride and tetrabutylammonium difluoride.
Citation Information
Patent Citations
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