Synthesis method of sodium tetrafluoropropionate
By using titanium-based or nickel-based active metal-coated oxide electrodes through the electrolysis of tetrafluoropropanol, the problems of toxic raw materials and environmental pollution in the synthesis of sodium tetrafluoropropionate have been solved, achieving efficient and green preparation of sodium tetrafluoropropionate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAMEN UNIV
- Filing Date
- 2024-11-11
- Publication Date
- 2026-05-12
AI Technical Summary
Existing sodium tetrafluoropropionate synthesis processes suffer from problems such as the use of highly toxic raw materials, environmental pollution, and low product yield, which limit its widespread application.
Sodium tetrafluoropropionate was prepared by electrocatalytic oxidation of tetrafluoropropanol under alkaline conditions using titanium-based or nickel-based active metal oxide coatings as the anode and nickel as the cathode.
This technology enables the efficient and environmentally friendly synthesis of sodium tetrafluoropropionate under mild conditions, improving product yield, reducing environmental pollution, and lowering production costs.
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Figure CN122013207A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical synthesis technology, and specifically discloses a method for synthesizing sodium tetrafluoropropionate. Background Technology
[0002] Sodium tetrafluoropropionate, a novel herbicide, is traditionally prepared through a nucleophilic addition reaction between tetrafluoroethylene and highly toxic sodium cyanide in a specific solvent system, followed by decomposition under mild alkaline conditions to yield the target product. This route is dominant in China, renowned for its mild and easily controllable reaction conditions, high conversion rate, and good yield. However, this process requires high-purity tetrafluoroethylene and highly toxic sodium cyanide, and the residual cyanide ions in the product significantly limit its market application. Currently, the use of this method is restricted abroad.
[0003] Another method uses tetrafluoropropanol as a raw material and potassium permanganate as an oxidant. However, the use of potassium permanganate is highly polluting and violates the principles of green chemistry. Against this backdrop, Chinese patent CN101125811A proposed an innovative method using hydrogen peroxide as an oxidant to synthesize sodium tetrafluoropropionate. This hydrogen peroxide method not only simplifies the reaction products and reduces the environmental burden, but also helps lower overall production costs due to the lower cost of hydrogen peroxide. However, this strategy also faces challenges, such as the need to improve product yield, and the inherent hazards of hydrogen peroxide itself, limiting its widespread application.
[0004] Therefore, it is particularly important to develop an oxidation technology that is both green and safe, and also sustainable. Summary of the Invention
[0005] To address the problems existing in the prior art, the first aspect of this invention discloses an electrochemical synthesis method for sodium tetrafluoropropionate, comprising: adding the substrate tetrafluoropropanol to an electrolyte, using a titanium-based active metal oxide or a nickel-based active metal oxide as the anode and nickel as the cathode, and performing electrolysis to obtain sodium tetrafluoropropionate, as shown in the reaction formula:
[0006]
[0007] The electrolyte comprises a soluble nickel salt and an alkali, with water as the solvent.
[0008] In some specific embodiments of the first aspect, the concentration of tetrafluoropropanol in the alkaline electrolyte is 0.5–5 mmol / ml, in some embodiments it is 0.5 mmol / ml, in some embodiments it is 1.5 mmol / ml, in some embodiments it is 2.5 mmol / ml, in some embodiments it is 3.5 mmol / ml, and in some embodiments it is 5.0 mmol / ml.
[0009] In some specific embodiments of the first aspect, the alkaline feedstock of the electrolyte is selected from sodium hydroxide and potassium hydroxide.
[0010] In some specific embodiments of the first aspect, the concentration of the alkaline feed is 0.5–10.0 mmol / ml, in some embodiments it is 0.5 mmol / ml, in some embodiments it is 3.5 mmol / ml, in some embodiments it is 6.5 mmol / ml, in some embodiments it is 10.0 mmol / ml, and in some preferred embodiments of the first aspect, the concentration of the alkaline feed is 3.6 mmol / ml.
[0011] In some specific embodiments of the first aspect, the current density is selected from 5 to 300 mA / cm². 2 In some preferred embodiments of the first aspect, the current density is selected from 20 mA / cm². 2 .
[0012] In some specific embodiments of the first aspect, the electrolysis temperature is 20–60°C, in some embodiments it is 30°C, in some embodiments it is 40°C, in some embodiments it is 50°C, and in some embodiments it is 60°C.
[0013] In some specific embodiments of the first aspect, the cathode material is a nickel sheet, a nickel mesh, or nickel foam.
[0014] In some specific embodiments of the first aspect, the added soluble nickel salt includes one or more of nickel sulfate, nickel acetate, and nickel nitrate.
[0015] In some specific embodiments of the first aspect, the concentration of the soluble nickel salt is 0.001–0.1 mmol / mL, in some embodiments it is 0.03 mmol / mL, in some embodiments it is 0.06 mmol / mL, in some embodiments it is 0.09 mmol / mL, and in some preferred embodiments of the first aspect, the concentration of the soluble nickel salt is 0.05 mmol / mL.
[0016] In some specific embodiments of the first aspect, the method for preparing the titanium-based active metal coated oxide electrode or the nickel-based active metal coated oxide electrode includes:
[0017] S1: Grind and polish the titanium or nickel sheet, clean it with acid and water using ultrasonic cleaning, wash it with alcohol, and dry it;
[0018] S2: The preparation includes an electroplating solution containing soluble nickel salts and alkali;
[0019] S3: A titanium or nickel sheet is placed in an electroplating solution and electroplated using alternating current to obtain a titanium-based active metal oxide electrode or a nickel-based active metal oxide electrode, respectively.
[0020] In some specific embodiments of the first aspect, the nickel salt in the electroplating solution in step S2 is selected from nickel sulfate and nickel nitrate.
[0021] In some specific embodiments of the first aspect, the molar ratio of nickel ions to alkali in the electroplating solution of step S2 is (52.0-71.0):(47.5-52.5).
[0022] In some specific embodiments of the first aspect, the alkali in step S2 is selected from potassium hydroxide and sodium hydroxide.
[0023] In some specific embodiments of the first aspect, the waveform of the alternating current in step S3 is an asymmetrical square wave.
[0024] In some specific embodiments of the first aspect, the AC frequency of step S3 is 1 / 55 to 1 / 65 Hz, preferably 1 / 60 Hz.
[0025] In some specific embodiments of the first aspect, the duty cycle of the asymmetric square wave in step S3 is 50-70%, preferably 67%.
[0026] In some specific embodiments of the first aspect, the current density of the alternating current in step S3 is 5–30 mA / cm². 2 .
[0027] All reagents used in this invention are purchased from the open and legal market and have not undergone further purification.
[0028] Advantages of this invention:
[0029] The electrocatalytic oxidation technology proposed in this invention uses titanium-based or nickel-based active metal oxide coatings as the anode and nickel as the cathode. With the participation of soluble metal salts, including nickel salts, tetrafluoropropanol is oxidized under alkaline conditions through this electrode combination to obtain sodium tetrafluoropropionate. This electrolysis can be carried out under mild conditions, which is environmentally friendly. Through screening of various conditions, a high-yield technical solution has been obtained. The electrocatalytic system has been continuously optimized, which has increased the electrolysis yield. It is expected to overcome the limitations of existing methods and promote the efficient and green synthesis of sodium tetrafluoropropionate. Attached Figure Description
[0030] Figure 1 The NMR 1H spectrum of sodium tetrafluoropropionate prepared according to this invention is shown;
[0031] Figure 2 The NMR fluorine spectrum of sodium tetrafluoropropionate prepared according to the present invention is shown. Detailed Implementation
[0032] Through the following detailed description of embodiments of the present invention in conjunction with the accompanying drawings and specific implementation details, those skilled in the art will gain a clearer and more thorough understanding of the further features, advantages, and effects of the present invention.
[0033] Fabrication of titanium-based active metal coated oxide electrodes or nickel-based active metal coated oxide electrodes:
[0034] Substrate processing:
[0035] Step 1: Place a titanium or nickel substrate (1mm × 10cm) 2 Polish the product, soak it in dilute sulfuric acid for 30 minutes, ultrasonically clean it with deionized water for 30 minutes, clean it with ethanol for 30 minutes, and finally dry it in an oven at 100℃ for 6 hours.
[0036] Active metal layer deposition:
[0037] Step 2: Prepare the electroplating solution: Weigh 1.9-2.1g of potassium hydroxide and 8-11g of nickel sulfate, and dissolve them together in 150mL of water.
[0038] Step 3: Place the titanium or nickel sheet in the electroplating solution and apply an asymmetric square wave alternating current (frequency 1 / 55 to 1 / 65 Hz, duty cycle 50 to 70%) with a current density of 5 to 30 mA / cm². 2 Under the given conditions, electroplating was performed for 20 minutes to obtain titanium-based active metal oxide electrodes or nickel-based active metal oxide electrodes according to electroplating schemes 1 to 4.
[0039] Table 1: Electroplating Conditions
[0040]
[0041] Preparation by electrolysis of sodium tetrafluoropropionate:
[0042] An electrolyte solution comprising 0.5–5 mmol / mL tetrafluoropropanol, 0.001–0.1 mmol / mL nickel sulfate, and 60–400 mg / mL NaOH was prepared using water as a solvent. A magnetic inductor and an insertion electrode were then added (the anode in Examples 1–4 was a titanium-based active metal oxide electrode, and the cathode was a nickel sheet; the anode in Example 5 was a nickel-based active metal oxide electrode). The current density was 5–300 mA / cm². 2 Under the electrolysis conditions, 4.5 F of charge is electrolyzed at 20–60 °C. After the reaction solution is dried by rotary evaporation, recrystallization yields the product sodium tetrafluoropropionate.
[0043] Table 2: Sodium tetrafluoropropionate yield in Examples 1-5
[0044]
[0045] Comparative Example 1 and Comparative Example 1-1:
[0046] The conditions and methods for Comparative Example 1 and Example 1 were the same, except that the NaOH concentration was changed to 30 mg / mL, and the reaction solution was evaporated to dryness and recrystallized to obtain sodium tetrafluoropropionate. The yield was then measured.
[0047] Under the same conditions as Comparative Example 1, the titanium substrate was replaced with a nickel substrate to make Comparative Example 1-1.
[0048] Comparative Example 2 and Comparative Example 2-1:
[0049] The conditions and methods for Comparative Example 2 and Example 1 were the same, except that the NaOH concentration was changed to 505 mg / mL. After the reaction solution was evaporated to dryness, sodium tetrafluoropropionate was obtained by recrystallization, and the yield was measured.
[0050] Under the same conditions as Comparative Example 2, the titanium substrate was replaced with a nickel substrate to make Comparative Example 2-1.
[0051] Comparative Example 3 and Comparative Example 3-1:
[0052] The conditions and methods for Comparative Example 3 and Example 1 were the same, except that sodium hydroxide was not added. After the reaction solution was evaporated to dryness, sodium tetrafluoropropionate was obtained by recrystallization, and the yield was measured.
[0053] Under the same conditions as Comparative Example 3, the titanium substrate was replaced with a nickel substrate to make Comparative Example 3-1.
[0054] Comparative Example 4 and Comparative Example 4-1:
[0055] The conditions and methods for Comparative Example 4 and Example 1 were the same, except that sodium hydroxide was not added, and an acidic system of 5 mg / mL sulfuric acid was used in the electrolyte. After the reaction solution was evaporated to dryness, sodium tetrafluoropropionate was obtained by recrystallization, and the yield was measured.
[0056] Under the same conditions as Comparative Example 4, the titanium substrate was replaced with a nickel substrate to make Comparative Example 4-1.
[0057] Comparative Example 5 and Comparative Example 5-1:
[0058] The conditions and methods for Comparative Example 5 and Example 1 were the same, except that the electrolysis temperature was maintained at 3°C, the reaction solution was dried by rotary evaporation, and sodium tetrafluoropropionate was obtained by recrystallization, with a yield of 1%.
[0059] Under the same conditions as Comparative Example 5, the titanium substrate was replaced with a nickel substrate to make Comparative Example 5-1.
[0060] Comparative Example 6 and Comparative Example 6-1:
[0061] The conditions and methods for Comparative Example 6 and Example 1 were the same, except that the electrolysis temperature was maintained at 85°C, the reaction solution was dried by rotary evaporation, and sodium tetrafluoropropionate was obtained by recrystallization, with a yield of 1%.
[0062] Under the same conditions as Comparative Example 6, the titanium substrate was replaced with a nickel substrate to make Comparative Example 6-1.
[0063] Comparative Example 7 and Comparative Example 7-1:
[0064] The conditions and methods for Comparative Example 7 and Example 1 were the same, except that nickel sulfate was not added. After the reaction solution was evaporated to dryness, sodium tetrafluoropropionate was obtained by recrystallization, and the yield was measured.
[0065] Under the same conditions as Comparative Example 7, the titanium substrate was replaced with a nickel substrate to make Comparative Example 7-1.
[0066] Comparative Example 8 and Comparative Example 8-1:
[0067] Comparative Example 8 and Example 1 were conducted under the same conditions and methods, except that nickel sulfate was not added and ferric sulfate was added instead. The concentration of ferric ions in the electrolyte was 0.05 mmol / mL. After the reaction solution was evaporated to dryness, sodium tetrafluoropropionate was obtained by recrystallization, and the yield was measured.
[0068] Under the same conditions as Comparative Example 8, the titanium substrate was replaced with a nickel substrate to make Comparative Example 8-1.
[0069] Table 3: Yield of sodium tetrafluoropropionate in Comparative Examples 1–8 and Examples 1–8–1
[0070]
[0071] In Table 3, × represents no input, — represents the same as in Example 1, and ND indicates no detection.
[0072] Comparative Example 9 and Comparative Example 9-1:
[0073] The difference between Comparative Example 9 and Example 1 lies in the fabrication of the titanium-based active metal oxide electrode. The difference between Comparative Example 9 and Example 1 lies in step 2. In step 2 of Comparative Example 9, 10g of copper sulfate was added to the electroplating solution instead of nickel sulfate, and the yield was measured.
[0074] Under the same conditions as Comparative Example 9, the titanium substrate was replaced with a nickel substrate to make Comparative Example 9-1.
[0075] Comparative Example 10 and Comparative Example 10-1:
[0076] The difference between Comparative Example 10 and Example 1 lies in the fabrication of the titanium-based active metal oxide electrode. The difference between Comparative Example 10 and Example 1 lies in step 2. In step 2 of Comparative Example 10, 1g of nickel sulfate was added to the electroplating solution, and the yield was measured.
[0077] Under the same conditions as Comparative Example 10, the titanium substrate was replaced with a nickel substrate to make Comparative Example 10-1.
[0078] Comparative Example 11 and Comparative Example 11-1:
[0079] The difference between Comparative Example 11 and Example 1 lies in the fabrication of the titanium-based active metal oxide electrode. The difference between Comparative Example 11 and Example 1 lies in step 2. In step 2 of Comparative Example 11, 35g of nickel sulfate was added to the electroplating solution, and the yield was measured.
[0080] Under the same conditions as Comparative Example 11, the titanium substrate was replaced with a nickel substrate to make Comparative Example 11-1.
[0081] Comparative Example 12 and Comparative Example 12-1:
[0082] The difference between Comparative Example 12 and Example 1 lies in the fabrication of the titanium-based active metal oxide electrode. The difference between Comparative Example 12 and Example 1 lies in step 2. In Comparative Example 12, nickel sulfate is not added to the electroplating solution in step 2. The yield was measured.
[0083] Under the same conditions as Comparative Example 12, the titanium substrate was replaced with a nickel substrate to make Comparative Example 12-1.
[0084] Comparative Example 13 and Comparative Example 13-1:
[0085] The difference between Comparative Example 13 and Example 1 lies in the fabrication of the titanium-based active metal oxide electrode. The difference between Comparative Example 13 and Example 1 lies in step 2. In step 2 of Comparative Example 13, potassium hydroxide is not added to the electroplating solution, and the yield is measured.
[0086] Under the same conditions as Comparative Example 13, the titanium substrate was replaced with a nickel substrate to make Comparative Example 13-1.
[0087] Table 4: Yield of sodium tetrafluoropropionate in Comparative Examples 9–13 and 9-1–13-1
[0088]
[0089] In Table 4, × represents no input, and — represents the same as in Example 1.
[0090] Comparative Example 14 and Comparative Example 14-1:
[0091] The difference between Comparative Example 14 and Example 1 lies in the fabrication of the titanium-based active metal coated oxide electrode. The difference between Comparative Example 14 and Example 1 lies in step 3. In step 3 of Comparative Example 14, an asymmetric square wave alternating current with a frequency of 1 / 20 Hz is used, and the yield is measured.
[0092] Under the same conditions as Comparative Example 14, the titanium substrate was replaced with a nickel substrate to make Comparative Example 14-1.
[0093] Comparative Example 15 and Comparative Example 15-1:
[0094] The difference between Comparative Example 15 and Example 1 lies in the fabrication of the titanium-based active metal coated oxide electrode. The difference between Comparative Example 15 and Example 1 lies in step 3. In step 3 of Comparative Example 15, an asymmetric square wave AC current with a frequency of 1 / 100 Hz is used, and the yield is measured.
[0095] Under the same conditions as Comparative Example 15, the titanium substrate was replaced with a nickel substrate to make Comparative Example 15-1.
[0096] Comparative Example 16 and Comparative Example 16-1:
[0097] The difference between Comparative Example 16 and Example 1 lies in the fabrication of the titanium-based active metal coated oxide electrode. The difference between Comparative Example 16 and Example 1 lies in step 3. In step 3 of Comparative Example 16, an asymmetric square wave alternating current with a duty cycle of 25% is used, and the yield is measured.
[0098] Under the same conditions as Comparative Example 16, the titanium substrate was replaced with a nickel substrate to make Comparative Example 16-1.
[0099] Comparative Example 17 and Comparative Example 17-1:
[0100] The difference between Comparative Example 17 and Example 1 lies in the fabrication of the titanium-based active metal coated oxide electrode. The difference between Comparative Example 17 and Example 1 lies in step 3. In step 3 of Comparative Example 17, an asymmetric square wave alternating current with a duty cycle of 90% is used, and the yield is yielded.
[0101] Under the same conditions as Comparative Example 17, the titanium substrate was replaced with a nickel substrate to make Comparative Example 17-1.
[0102] Comparative Example 18 and Comparative Example 18-1:
[0103] The difference between Comparative Example 18 and Example 1 lies in the fabrication of the titanium-based active metal-coated oxide electrode. The difference between Comparative Example 18 and Example 1 lies in step 3. In Comparative Example 18, step 3 uses an asymmetric square wave alternating current of 1.2 mA / cm². 2 The yield rate was %.
[0104] Under the same conditions as Comparative Example 18, the titanium substrate was replaced with a nickel substrate to make Comparative Example 18-1.
[0105] Comparative Example 19 and Comparative Example 19-1:
[0106] The difference between Comparative Example 19 and Example 1 lies in the fabrication of the titanium-based active metal-coated oxide electrode. The difference also lies in step 3; in Comparative Example 19, step 3 uses an asymmetric square wave alternating current of 60.0 mA / cm². 2 The yield rate was %.
[0107] Under the same conditions as Comparative Example 19, the titanium substrate was replaced with a nickel substrate to make Comparative Example 19-1.
[0108] Comparative Example 20 and Comparative Example 20-1:
[0109] The difference between Comparative Example 20 and Example 1 lies in the fabrication of the titanium-based active metal coated oxide electrode. The difference between Comparative Example 20 and Example 1 lies in step 3. In Comparative Example 20, step 3 uses a sinusoidal alternating current, and the yield is measured.
[0110] Under the same conditions as Comparative Example 20, the titanium substrate was replaced with a nickel substrate to make Comparative Example 20-1.
[0111] Comparative Example 21:
[0112] The difference between Comparative Example 21 and Example 1 is that the anode uses a graphite electrode instead of a titanium-based active metal coated oxide electrode, and the yield is measured.
[0113] Comparative Example 22:
[0114] The difference between Comparative Example 22 and Example 1 is that the anode uses an untreated nickel plate and does not undergo an active metal layer deposition operation, resulting in a yield of %.
[0115] Comparative Example 23:
[0116] The difference between Comparative Example 23 and Example 1 is that the anode uses an untreated titanium plate and does not undergo an active metal layer deposition operation, resulting in a yield of %.
[0117] Table 5: Yield of sodium tetrafluoropropionate in Comparative Examples 14–23 and 14–20–1
[0118]
[0119] In Table 5, — represents the same as in Example 1, and △ represents that it does not exist.
[0120] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.
Claims
1. A method for the electrosynthesis of sodium tetrafluoropropionate, comprising: The substrate tetrafluoropropanol is added to the electrolyte, and electrolysis is performed using titanium-based active metal oxide or nickel-based active metal oxide as the anode and nickel as the cathode to obtain sodium tetrafluoropropionate. The reaction formula is as follows: The electrolyte comprises a soluble nickel salt and an alkali, with water as the solvent.
2. The electrosynthesis method of sodium tetrafluoropropionate according to claim 1, characterized in that, The concentration of tetrafluoropropanol in the alkaline electrolyte is 0.5–5 mmol / ml.
3. The method for electrosynthesizing sodium tetrafluoropropionate according to claim 1 or 2, characterized in that, The alkaline feedstock of the electrolyte is selected from sodium hydroxide, potassium hydroxide, and / or, and the concentration of the alkaline feedstock is 0.5 to 10 mmol / ml, preferably 3.6 mmol / ml.
4. The method for electrosynthesizing sodium tetrafluoropropionate according to any one of claims 1 to 3, characterized in that, The current density is selected from 5 to 300 mA / cm². 2 20mA / cm is preferred 2 .
5. The method for electrosynthesizing sodium tetrafluoropropionate according to any one of claims 1 to 4, characterized in that, The electrolysis temperature is 20–60°C.
6. The method for electrosynthesizing sodium tetrafluoropropionate according to any one of claims 1 to 5, characterized in that, The cathode material is nickel sheet, nickel mesh, or nickel foam.
7. The method according to claims 1 to 6, characterized in that, The added soluble nickel salt includes one or more of nickel sulfate, nickel acetate, and nickel nitrate, and / or the concentration of the soluble nickel salt is 0.001 to 0.1 mmol / mL, preferably 0.05 mmol / mL.
8. The method for electrosynthesizing sodium tetrafluoropropionate according to any one of claims 1 to 7, characterized in that, The method for preparing the titanium-based active metal coated oxide electrode or the nickel-based active metal coated oxide electrode includes: S1: Grind and polish the titanium or nickel sheet, clean it with acid and water using ultrasonic cleaning, wash it with alcohol, and dry it; S2: The preparation includes an electroplating solution containing soluble nickel salts and alkali; S3: A titanium or nickel sheet is placed in an electroplating solution and electroplated using alternating current to obtain a titanium-based active metal oxide electrode or a nickel-based active metal oxide electrode, respectively.
9. The electrosynthesis method of sodium tetrafluoropropionate according to claim 8, characterized in that, In step S2, the nickel salt in the electroplating solution is selected from nickel sulfate, nickel nitrate, and / or the molar ratio of nickel ions to alkali in the electroplating solution in step S2 is (52.0-71.0):(47.5-52.5), and / or the alkali in step S2 is selected from potassium hydroxide and sodium hydroxide.
10. The method for electrosynthesizing sodium tetrafluoropropionate according to any one of claims 8 or 9, characterized in that, The waveform of the alternating current in step S3 is an asymmetrical square wave, and / or the frequency of the alternating current in step S3 is 1 / 55 to 1 / 65 Hz, preferably 1 / 60 Hz, and / or the duty cycle of the asymmetrical square wave in step S3 is 50 to 70%, preferably 67%, and / or the current density of the alternating current in step S3 is 5 to 30 mA / cm². 2 .