Synthesis method of sodium 2, 2, 3, 3-tetrafluoropropionate
By combining the oxidation reaction and neutralization reaction of 2,2,3,3-tetrafluoropropanol, the problems of low synthesis yield of sodium 2,2,3,3-tetrafluoropropanate and the use of highly toxic reagents in the prior art are solved, and an efficient and environmentally friendly synthesis process is achieved.
Patent Information
- Application Number
- CN202411751599.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-02
- Publication Date
- 2025-02-25
AI Technical Summary
In the prior art, the synthesis method of sodium 2,2,3,3-tetrafluoropropionate has problems such as low yield, highly toxic reagents, and expensive equipment, and is also very harmful to the environment and humans.
2,2,3,3-tetrafluoropropanol is oxidized under the action of an oxidizing agent (such as potassium permanganate and ozone) to obtain 2,2,3,3-tetrafluoropropanoic acid, and then neutralize it with an inorganic base to produce sodium 2,2,3,3-tetrafluoropropanoic acid.
The synthesis of sodium 2,2,3,3-tetrafluoropropionate with mild reaction conditions, high yield and product purity was achieved, avoiding the use of highly toxic reagents, reducing equipment costs, and simplifying the production process.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of chemical engineering, and in particular to a method for synthesizing sodium 2,2,3,3-tetrafluoropropionate. Background Art
[0002] Sodium tetrafluoropropionate is a new type of herbicide, mainly used in sugarcane fields, forests, tropical grasslands, rubber plantations, tea gardens, etc. It has the characteristics of long-lasting, degradable, non-toxic and harmless. It is particularly effective in removing sawgrass and African grass, and is not toxic to humans and animals. The current synthesis route of this compound is as follows:
[0003] 1. Tetrafluoroethylene and sodium cyanide undergo nucleophilic addition reaction, and then decompose in alkaline medium to generate sodium tetrafluoropropionate. Since the raw material used in this process is sodium cyanide and the product is prone to contain cyanide ions, the use of the product is greatly restricted.
[0004] 2. Use pure oxygen or compressed air as an oxidant to oxidize 2,2,3,3-tetrafluoropropanol to 2,2,3,3-tetrafluoropropionic acid. This method needs to be carried out under ultraviolet light, requires an expensive photoreactor, and is difficult to achieve large-scale production.
[0005] 3. Using 2,2,3,3-tetrafluoropropanol as raw material, electrocatalytic preparation of sodium 2,2,3,3-tetrafluoropropionate. This method requires the use of electrocatalytic equipment, is difficult to scale up, and has high costs.
[0006] The current route has disadvantages such as low yield, use of highly toxic reagents, expensive equipment, etc., and is highly harmful to the environment and humans. Summary of the invention
[0007] In view of this, the technical problem to be solved by the present invention is to provide a method for synthesizing sodium 2,2,3,3-tetrafluoropropionate, with mild reaction conditions, high reaction yield and product purity.
[0008] To achieve the above object, the present invention provides a method for synthesizing sodium 2,2,3,3-tetrafluoropropionate, comprising the following steps:
[0009] Under the oxidizing action of an oxidant, 2,2,3,3-tetrafluoropropanol undergoes an oxidation reaction to obtain 2,2,3,3-tetrafluoropropionic acid; the 2,2,3,3-tetrafluoropropionic acid undergoes a neutralization reaction with an inorganic base to obtain sodium 2,2,3,3-tetrafluoropropionate;
[0010] The oxidant is selected from one or more of potassium permanganate, manganese dioxide and ozone.
[0011] The equation for the above reaction is as follows:
[0012]
[0013] The solvent for the oxidation reaction preferably includes one or more of water, tetrahydrofuran, dioxane, dichloromethane, and ethyl acetate, and more preferably water.
[0014] The molar ratio of the 2,2,3,3-tetrafluoropropanol to the potassium permanganate is preferably 1:(0.5-5), more preferably 1:(0.5-2), further preferably 1:(0.75-1.5), specifically 1:0.75, 1:1.2 or 1:1.5, or a range value with the above values as the upper or lower limit, and most preferably 1:1.5.
[0015] The molar ratio of the 2,2,3,3-tetrafluoropropanol to the manganese dioxide is 1:(1-10), more preferably 1:(3-7), and even more preferably 1:5.
[0016] When ozone is used as the oxidant, the ozone is preferably 1% to 5%, more preferably 2% to 4%, and further preferably 3%. The ozone flow rate is preferably 10 to 30 mL / min, more preferably 15 to 25 mL / min, and further preferably 20 mL / min.
[0017] When the oxidant is potassium permanganate, preferably, acid is added during the oxidation reaction to adjust the acidity of the system to improve the oxidation performance of potassium permanganate and achieve a higher yield of the reaction.
[0018] The acid preferably includes one or more of sulfuric acid, hydrochloric acid, phosphoric acid, trifluoroacetic acid, acetic acid, and tetrafluoroboric acid.
[0019] The molar ratio of the 2,2,3,3-tetrafluoropropanol to the acid is preferably 1:(0.01-5); more preferably 1:(0.5-2), further preferably 1:(0.75-2), and even more preferably 1:(1.5-2). Specifically, it can be 1:0.75, 1:1.2, 1:1.5, 1:2, or a range value with the above values as the upper or lower limits, and most preferably 1:1.5.
[0020] The temperature of the oxidation reaction is preferably 50-100°C, more preferably 70-80°C.
[0021] When the oxidant is potassium permanganate, preferably, a base is added during the oxidation reaction to adjust the alkalinity of the system to improve the oxidation performance of potassium permanganate and achieve a higher yield of the reaction.
[0022] The base preferably includes one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, triethylamine, diethylamine, and aqueous ammonia.
[0023] The molar ratio of the 2,2,3,3-tetrafluoropropanol to the base is preferably 1:(0.01-5); more preferably 1:(0.5-2), further preferably 1:(0.75-2), and even more preferably 1:(1.5-2). Specifically, it can be 1:0.75, 1:1.2, 1:1.5, 1:2, or a range value with the above values as the upper or lower limits, and most preferably 1:1.5.
[0024] The temperature of the oxidation reaction is preferably 50-100°C, more preferably 70-80°C.
[0025] When the oxidant is manganese dioxide, preferably, the temperature of the oxidation reaction is 50-120°C, more preferably 90-100°C.
[0026] When the oxidant is ozone, preferably, acid is added during the oxidation reaction to adjust the acidity of the system to improve the oxidation performance of potassium permanganate and achieve a higher yield of the reaction.
[0027] The acid preferably includes one or more of sulfuric acid, hydrochloric acid, phosphoric acid, trifluoroacetic acid, acetic acid, and tetrafluoroboric acid.
[0028] The molar ratio of the 2,2,3,3-tetrafluoropropanol to the acid is 1:(0.01-5); more preferably 1:(0.5-2), further preferably 1:(0.75-2), and even more preferably 1:(1.5-2). Specifically, it can be 1:0.75, 1:1.2, 1:1.5, 1:2, or a range value with the above values as the upper or lower limits, and most preferably 1:1.5.
[0029] The temperature of the oxidation reaction is preferably 80-120°C, more preferably 90-100°C.
[0030] When the oxidant is ozone, preferably, a base is added during the oxidation reaction to adjust the alkalinity of the system to improve the oxidation performance of potassium permanganate and achieve a higher yield of the reaction.
[0031] The base preferably includes one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, triethylamine, diethylamine, and aqueous ammonia.
[0032] The molar ratio of the 2,2,3,3-tetrafluoropropanol to the base is preferably 1:(0.01-5); more preferably 1:(0.5-2), further preferably 1:(0.75-2), and even more preferably 1:(1.5-2). Specifically, it can be 1:0.75, 1:1.2, 1:1.5, 1:2, or a range value with the above values as the upper or lower limits, and most preferably 1:1.5.
[0033] The temperature of the oxidation reaction is preferably 80-120°C, more preferably 90-100°C.
[0034] The present invention has no particular limitation on the inorganic base used in the neutralization reaction between the 2,2,3,3-tetrafluoropropionic acid and the inorganic base, and preferably includes one or more of sodium hydroxide, sodium carbonate, and sodium bicarbonate.
[0035] Preferably, after the neutralization reaction is completed, residual water in the system is removed by vacuum distillation, and then an organic solvent is added for pulping, filtering and drying to obtain sodium 2,2,3,3-tetrafluoropropionate.
[0036] Compared with the prior art, the present invention provides a method for synthesizing sodium 2,2,3,3-tetrafluoropropionate, comprising the following steps: 2,2,3,3-tetrafluoropropanol undergoes an oxidation reaction under the oxidizing action of an oxidant to obtain 2,2,3,3-tetrafluoropropionic acid; the 2,2,3,3-tetrafluoropropionic acid undergoes a neutralization reaction with an inorganic base to obtain sodium 2,2,3,3-tetrafluoropropionate; the oxidant is selected from one or more of potassium permanganate, manganese dioxide and ozone.
[0037] The present invention has the following beneficial effects: (1) the oxidant used is safe; (2) the reaction conditions are mild, no excessive temperature or pressure is required, the equipment requirements are low, and it is easy to industrialize the production; (3) the reaction yield is relatively high, and the yield is above 90%; (4) the impurity sodium difluoroacetate is less than 0.5%, and the sodium difluoroacetate limit in the national sodium tetrafluoropropionate standard is less than 2.5%, which meets the national requirements; (5) the product has high purity, which can reach more than 99%; (6) no highly toxic reagents are used in the preparation process. DETAILED DESCRIPTION
[0038] In order to further illustrate the present invention, the following is a detailed description in conjunction with the embodiments. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention.
[0039] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.
[0040] The yield calculation formula in the following examples is as follows:
[0041]
[0042] Example 1
[0043] Synthesis of tetrafluoropropionic acid:
[0044] At room temperature, add 60g (0.455mol) of 2,2,3,3-tetrafluoropropanol and 900mL of deionized water in a 1000mL three-necked flask. Turn on the mechanical stirring and add 89.18g (0.91mol) of concentrated sulfuric acid dropwise. During the addition, control the temperature in the bottle to be less than 50°C. After the addition is completed, the oil bath is heated to 70°C. Add 107.8g (0.68mol) of solid potassium permanganate to the reaction bottle in batches. During the addition, control the temperature in the bottle to 70-80°C. After the addition is completed, keep the reaction warm for 2 hours. GC detection shows that the purity of tetrafluoropropanol is less than 1%, the purity of 2,2,3,3-tetrafluoropropionic acid is 97%, and the yield is 94.1%.
[0045] Synthesis of Sodium Tetrafluoropropionate:
[0046] Add solid sodium thiosulfate to the reaction flask in the previous step until the potassium iodide test paper does not turn blue. The water and 2,2,3,3-tetrafluoropropionic acid in the reaction flask are evaporated under reduced pressure, and the oil bath temperature is 70-100°C. Use 30% sodium hydroxide solution to neutralize the distillate to pH = 7.0. The water is dried under reduced pressure, 100mL acetonitrile is used to azeotropically remove water, and 100mL acetonitrile is used to beat the pulp, filter and dry to obtain 69.5g of solid sodium 2,2,3,3-tetrafluoropropionate, with a purity of 99.2% and a total yield of 90.3% in two steps. The impurity sodium difluoroacetate content is 0.1%.
[0047] Embodiment 2:
[0048] Synthesis of tetrafluoropropionic acid:
[0049] At room temperature, add 60g (0.455mol) of 2,2,3,3-tetrafluoropropanol and 900mL of deionized water in a 1000mL three-necked flask. Heat the oil bath to 70°C. Add 198g (2.28mol) of active manganese dioxide to the reaction flask in batches, and control the temperature in the flask to 70-80°C during the addition process. After the addition is completed, keep the reaction warm for 10 hours. GC detection shows that the purity of tetrafluoropropanol is less than 5%, the purity of 2,2,3,3-tetrafluoropropionic acid is 92%, and the yield is 89.2%.
[0050] Synthesis of Sodium Tetrafluoropropionate:
[0051] Lower the temperature in the reaction flask to 20-30°C. Filter by suction, and wash the filter cake with 150 mL of water. Distill the water and 2,2,3,3-tetrafluoropropionic acid in the filtrate under reduced pressure, and the oil bath temperature is 70-100°C. Neutralize the distillate with 30% sodium hydroxide solution to pH = 7.0. Dry the water under reduced pressure, and slurry with 100 mL of acetonitrile, filter and dry to obtain 65 g of solid sodium 2,2,3,3-tetrafluoropropionate, with a purity of 99.1% and a yield of 84.3%. The impurity sodium difluoroacetate content is 0.15%.
[0052] Embodiment 3:
[0053] Synthesis of tetrafluoropropionic acid:
[0054] At room temperature, add 60g (0.455mol) of 2,2,3,3-tetrafluoropropanol and 900mL of deionized water in a 1000mL three-necked flask. Turn on the mechanical stirring and add 4.9g (0.05mol) of concentrated sulfuric acid dropwise. During the addition, the temperature in the bottle is controlled to be less than 50°C. After the addition is completed, the oil bath is heated to 90°C-100°C. Ozone (3%) is introduced into the reaction bottle in batches at a flow rate of 20mL / min, and the temperature in the bottle is controlled to be 90-100°C during the ventilation process. After 12 hours of ventilation reaction, the purity of tetrafluoropropanol detected by GC is less than 7%, the purity of 2,2,3,3-tetrafluoropropionic acid is 90.2%, and the yield is 87.5%.
[0055] Synthesis of Sodium Tetrafluoropropionate:
[0056] Nitrogen was introduced into the reaction flask to remove ozone. Water and 2,2,3,3-tetrafluoropropionic acid in the reaction flask were evaporated under reduced pressure, and the oil bath temperature was 70-100°C. The distillate was neutralized with 30% sodium hydroxide solution to pH = 7.0. The water was dried under reduced pressure, and 100 mL of acetonitrile was used for pulping, and 64 g of solid sodium 2,2,3,3-tetrafluoropropionate was obtained by filtration and drying, with a purity of 99.2% and a yield of 83.1%. The content of impurity sodium difluoroacetate was 0.08%.
[0057] Embodiment 4-8
[0058] The dosage of potassium permanganate is shown in Table 1, and the other steps are the same as in Example 1.
[0059] Table 1 Effect of potassium permanganate dosage (relative to 2,2,3,3-tetrafluoropropanol) on reaction yield
[0060]
[0061] Examples 9-14
[0062] The amount of sulfuric acid used is shown in Table 2, and the other steps are the same as in Example 1.
[0063] Table 2 Effect of sulfuric acid dosage (relative to 2,2,3,3-tetrafluoropropanol) on reaction yield
[0064]
[0065] Examples 15-18
[0066] The reaction temperature is shown in Table 3, and the other steps are the same as in Example 1.
[0067] Table 3 Effect of temperature on reaction yield
[0068]
[0069] It can be seen from the data in Tables 1 to 3 that the conversion rate and yield of the reaction can be improved by adding acid to adjust the acidity of the system. When 1.5 equivalents of potassium permanganate are used, the amount of acid added is 1.5 to 2 equivalents, and the reaction temperature is 70 to 80° C., the reaction has the highest conversion rate and yield. The present invention reduces the equipment cost of the reaction by optimizing the reaction conditions, and the generated products are easy to separate, thereby simplifying the production process.
[0070] Embodiment 19
[0071] Synthesis of tetrafluoropropionic acid:
[0072] At room temperature, add 60g (0.455mol) of 2,2,3,3-tetrafluoropropanol and 900mL of deionized water in a 1000mL three-necked flask. Turn on the mechanical stirring and add 18.2g (0.455mol) of sodium hydroxide dropwise. During the addition, control the temperature in the bottle to be less than 50°C. After the addition is completed, the oil bath is heated to 70°C. Add 107.8g (0.68mol) of solid potassium permanganate to the reaction bottle in batches. During the addition, control the temperature in the bottle to 70-80°C. After the addition is completed, keep the reaction warm for 2 hours. GC detection shows that the purity of tetrafluoropropanol is less than 5%, the purity of 2,2,3,3-tetrafluoropropionic acid is 94%, and the yield is 92.1%.
[0073] Synthesis of Sodium Tetrafluoropropionate:
[0074] Add solid sodium thiosulfate to the reaction flask in the previous step until the potassium iodide test paper does not turn blue. Filter to remove the byproduct manganese dioxide. The filtrate is neutralized with concentrated sulfuric acid to a pH of <1. The water and 2,2,3,3-tetrafluoropropionic acid in the reaction flask are evaporated under reduced pressure, and the oil bath temperature is 70-100°C. Use 30% sodium hydroxide solution to neutralize the distillate to pH = 7.0. The water is dried under reduced pressure, 100mL acetonitrile is used to azeotropically remove water, and 100mL acetonitrile is used to beat the pulp, filter and dry to obtain 67.6g of solid sodium 2,2,3,3-tetrafluoropropionate, with a purity of 98.5% and a total yield of 87.3% in two steps. The impurity sodium difluoroacetate content is 0.5%.
[0075] The above embodiments are only used to help understand the method and core idea of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.
Claims
1. A method for synthesizing sodium 2,2,3,3-tetrafluoropropionate, comprising the following steps: Under the oxidizing action of an oxidant, 2,2,3,3-tetrafluoropropanol undergoes an oxidation reaction to obtain 2,2,3,3-tetrafluoropropionic acid; the 2,2,3,3-tetrafluoropropionic acid undergoes a neutralization reaction with an inorganic base to obtain sodium 2,2,3,3-tetrafluoropropionate; The oxidant is selected from one or more of potassium permanganate, manganese dioxide and ozone.
2. The synthesis method according to claim 1, characterized in that The solvent for the oxidation reaction includes one or more of water, tetrahydrofuran, dioxane, dichloromethane, and ethyl acetate.
3. The synthesis method according to claim 1, characterized in that The molar ratio of the 2,2,3,3-tetrafluoropropanol to the potassium permanganate is 1:(0.5-5); The molar ratio of the 2,2,3,3-tetrafluoropropanol to the manganese dioxide is 1:(1-10).
4. The synthesis method according to claim 1, characterized in that The oxidant is potassium permanganate; During the oxidation reaction, acid is added to adjust the acidity of the system; The acid includes one or more of sulfuric acid, hydrochloric acid, phosphoric acid, trifluoroacetic acid, acetic acid, and tetrafluoroboric acid; The molar ratio of the 2,2,3,3-tetrafluoropropanol to the acid is 1:(0.01-5); The temperature of the oxidation reaction is 50-100°C.
5. The synthesis method according to claim 1, characterized in that The oxidant is potassium permanganate; During the oxidation reaction, alkali is added to adjust the alkalinity of the system; The base includes one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, triethylamine, diethylamine, and ammonia water; The molar ratio of the 2,2,3,3-tetrafluoropropanol to the base is 1:(0.01-5); The temperature of the oxidation reaction is 50-100°C.
6. The synthesis method according to claim 1, characterized in that The oxidant is manganese dioxide; The temperature of the oxidation reaction is 50-120°C.
7. The synthesis method according to claim 1, characterized in that The oxidant is ozone; During the oxidation reaction, acid is added to adjust the acidity of the system; The acid includes one or more of sulfuric acid, hydrochloric acid, phosphoric acid, trifluoroacetic acid, acetic acid, and tetrafluoroboric acid; The molar ratio of the 2,2,3,3-tetrafluoropropanol to the acid is 1:(0.01-5); The temperature of the oxidation reaction is 80-120°C.
8. The synthesis method according to claim 1, characterized in that The oxidant is ozone; During the oxidation reaction, alkali is added to adjust the alkalinity of the system; The base includes one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, triethylamine, diethylamine, and ammonia water; The molar ratio of the 2,2,3,3-tetrafluoropropanol to the base is 1:(0.01-5); The temperature of the oxidation reaction is 80-120°C.
9. The synthesis method according to any one of claims 1 to 8, characterized in that The inorganic base includes one or more of sodium hydroxide, sodium carbonate and sodium bicarbonate.
10. The synthesis method according to any one of claims 1 to 8, characterized in that After the neutralization reaction is completed, the residual water in the system is removed by vacuum distillation, and then an organic solvent is added for pulping, filtering and drying to obtain sodium 2,2,3,3-tetrafluoropropionate.