Treatment method of mixed salt generated by fluorination of diflufenican
By heating and separating the mixed salt of potassium fluoride and potassium chloride produced by fluorination of pyrolylamine in a mixed solution of solvent and water, the problem of difficult separation of potassium fluoride and potassium chloride in the prior art is solved, and the recovery of high purity and highly active potassium fluoride is achieved.
Patent Information
- Application Number
- CN202311585680.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-24
- Publication Date
- 2025-05-27
AI Technical Summary
The prior art is difficult to effectively separate the mixed salts of potassium fluoride and potassium chloride, resulting in the failure of efficient recycling of by-products.
By dissolving the mixed salt of potassium fluoride and potassium chloride produced by fluorination of pyrolylamine in a mixed solution of solvent and water, heating, cooling and filtering, precipitation and drying to separate high-purity potassium chloride and potassium fluoride, the activity of potassium fluoride is improved by spray drying technology.
The physical separation of potassium chloride and potassium fluoride was achieved, and high-purity potassium chloride and high-active potassium fluoride with a content of more than 99%, simplifying the process flow and improving the purity of the product.
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Figure CN120039902A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of fluorochemical industry, and particularly to a method for treating a mixed salt (potassium fluoride and potassium chloride) generated by the fluorination of flufenacet. Background Art
[0002] As a common fluorination reagent, potassium fluoride is not only widely used in the production of organic synthesis fluorochemical industry, but also because its aqueous solution is alkaline and can corrode glass and porcelain, it is often used in glass engraving, food preservation and electroplating industries. In addition, it can also be used as a welding flux, catalyst and desiccant for water removal, etc. Therefore, the demand for potassium fluoride is increasing year by year. Among them, in the production of fluorochemical industry, a large amount of by-product mixed salt of potassium fluoride and potassium chloride is generated. At present, the domestic separation methods are all to convert potassium chloride or potassium fluoride into another salt by methods such as hydrogen fluoride, fluosilicic acid, boron trifluoride, etc. to separate them, and the separation of the two mixed salts has not been truly realized. Summary of the Invention
[0003] The purpose of the present invention is to provide a method for treating a mixed salt (potassium fluoride and potassium chloride) generated by the fluorination of flufenacet in view of the large amount of mixed salt of potassium fluoride and potassium chloride generated during the fluorination of the intermediate difluoronitrobenzene of flufenacet.
[0004] In order to achieve the above purpose, the present invention adopts the following technical solutions:
[0005] A method for treating a mixed salt generated by the fluorination of flufenacet, dissolving the mixed salt of potassium fluoride and potassium chloride generated by the fluorination of flufenacet in a mixed solution of a solvent and water, heating and keeping warm, then cooling, filtering, precipitating and drying to obtain potassium chloride with a content of more than 99%, and heating the filtrate to remove the solvent and concentrate it to obtain an aqueous solution of potassium fluoride, which is spray-dried to obtain highly active potassium fluoride with a content of more than 99%.
[0006] The weight ratio of the mixed salt to water is 1:0.1 - 10.
[0007] Preferably, the weight ratio of the mixed salt to water is 1:0.1 - 5.
[0008] The weight ratio of the mixed salt to the solvent is 1:0.1 - 5.
[0009] The weight ratio of the mixed salt to the solvent is 1:0.1 - 3.
[0010] The solvent is one or more of methanol, ethanol, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, and acetonitrile.
[0011] Preferably, the solvent is one or more of ethanol, ethyl acetate, N,N-dimethylformamide, and acetonitrile.
[0012] Furthermore, the mixed salt of potassium fluoride and potassium chloride produced by fluorinating diflufenican is dissolved in a mixed solution of a solvent and water, heated to 75 - 100 °C and kept warm for 2 h, then cooled to room temperature, filtered, the precipitate collected and dried to obtain potassium chloride with a content of over 99%; the filtrate collected by filtration is heated to 100 - 160 °C for solvent removal and concentration to obtain an aqueous solution of potassium fluoride, which is spray-dried to obtain highly active potassium fluoride with a content of over 99%.
[0013] Advantages of the present invention:
[0014] According to the properties of the mixed salt, the present invention adds a solvent to change the solubility of the two salts in water, thereby realizing the physical separation of potassium chloride and potassium fluoride without involving any chemical reactions, thus providing a treatment process for the mixed salt of potassium fluoride and potassium chloride as an organic by-product, and the process is simple and easy to control. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is a flow chart of the treatment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0016] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.
[0017] The treatment method of the present invention is a pure physical separation method that does not involve any chemical reactions. By adding a solvent to change the solubility of the two salts, the separation of the two substances is realized, and the process is simple and easy to control.
[0018] In the following embodiments, the mixed salt of potassium fluoride and potassium chloride is the mixed salt (potassium fluoride and potassium chloride) produced by fluorinating diflufenican.
[0019] Example 1:
[0020] 100 g of the mixed salt of potassium fluoride and potassium chloride is put into a four-necked flask, and a mixed solution of 300 g of water and 20 g of N,N-dimethylformamide is added. It is heated to 100 °C and refluxed for 2 hours, cooled to room temperature, filtered, the precipitate collected and dried to obtain 80.6 g of recovered potassium chloride with a content of 99.1%;
[0021] The filtrate of the above filtration is heated to 100 °C for solvent removal and concentration. After solvent removal, an aqueous solution of potassium fluoride is obtained, which is spray-dried to obtain 18.2 g of highly active potassium fluoride with a content of 99.5%.
[0022] Example 2:
[0023] Into a four-necked flask, 100 g of a mixed salt of potassium fluoride and potassium chloride was added, and a mixed solution of 150 g of water and 50 g of ethyl acetate was added. The temperature was raised to 75 °C and refluxed for 2 hours. Then it was cooled to room temperature, filtered, the precipitate was collected and dried to obtain 81.1 g of recovered potassium chloride with a content of 99.3%;
[0024] The above-mentioned filtered filtrate was heated to 110 °C for solvent removal and concentration. After solvent removal, an aqueous solution of potassium fluoride was obtained, and 17.8 g of highly active potassium fluoride with a content of 99.2% was obtained by spray drying.
[0025] Example 3:
[0026] Into a four-necked flask, 100 g of a mixed salt of potassium fluoride and potassium chloride was added, and a mixed solution of 100 g of water and 100 g of acetonitrile was added. The temperature was raised to 80 °C and refluxed for 2 hours. Then it was cooled to room temperature, filtered, the precipitate was collected and dried to obtain 79.5 g of recovered potassium chloride with a content of 99.0%;
[0027] The above-mentioned filtered filtrate was heated to 120 °C for solvent removal and concentration. After solvent removal, an aqueous solution of potassium fluoride was obtained, and 20.1 g of highly active potassium fluoride with a content of 99.5% was obtained by spray drying.
[0028] Example 4:
[0029] Into a four-necked flask, 100 g of a mixed salt of potassium fluoride and potassium chloride was added, and a mixed solution of 50 g of water and 150 g of ethanol was added. The temperature was raised to 78 °C and refluxed for 2 hours. Then it was cooled to room temperature, filtered, the precipitate was collected and dried to obtain 81.8 g of recovered potassium chloride with a content of 99.2%;
[0030] The above-mentioned filtered filtrate was heated to 150 °C for solvent removal and concentration. After solvent removal, an aqueous solution of potassium fluoride was obtained, and 17.2 g of highly active potassium fluoride with a content of 99.6% was obtained by spray drying.
[0031] Comparative example:
[0032] Into a four-necked flask, 100 g of a mixed salt of potassium fluoride and potassium chloride was added, and a mixed solution of 50 g of water and 150 g of acetone was added. The temperature was raised to 56 °C and refluxed for 2 hours. Then it was cooled to room temperature, filtered, the precipitate was collected and dried to obtain 78.6 g of recovered potassium chloride with a content of 95.2%;
[0033] The above-mentioned filtered filtrate was heated to 120 °C for solvent removal and concentration. After solvent removal, an aqueous solution of potassium fluoride was obtained, and 21.4 g of highly active potassium fluoride with a content of 94.6% was obtained by spray drying.
[0034] In summary, according to the differences in the properties of the mixed salt, the present invention adds a special solvent to physically separate potassium fluoride and potassium chloride, without involving chemical reactions, so that the two substances are physically separated to obtain high-purity potassium fluoride and potassium chloride.
[0035] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, shall be covered by the protection scope of the present invention.
Claims
1. A method for treating the mixed salt produced by the fluorination of diflufenican, characterized in that: The mixed salt of potassium fluoride and potassium chloride produced by the fluorination of diflufenican is dissolved in a mixed solution of a solvent and water, heated to a certain temperature and kept warm, then cooled, filtered, and the precipitate is dried to obtain potassium chloride with a content of more than 99%. The filtrate is heated to remove the solvent and concentrated, and an aqueous solution of potassium fluoride is obtained, which is spray-dried to obtain highly active potassium fluoride with a content of more than 99%.
2. The treatment method according to claim 1, characterized in that The weight ratio of the mixed salt to water is 1:0.1 - 10.
3. The treatment method according to claim 2, characterized in that The weight ratio of the mixed salt to water is 1:0.1 - 5.
4. The treatment method according to claim 1, characterized in that The weight ratio of the mixed salt to the solvent is 1:0.1 - 5.
5. The treatment method according to claim 4, characterized in that The weight ratio of the mixed salt to the solvent is 1:0.1 - 3.
6. The treatment method according to claim 1, characterized in that The solvent is one or more of methanol, ethanol, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, and acetonitrile.
7. The treatment method according to claim 6, characterized in that The solvent is one or more of ethanol, ethyl acetate, N,N-dimethylformamide, and acetonitrile.
8. The treatment method according to any one of claims 1 - 7, characterized in that The mixed salt of potassium fluoride and potassium chloride produced by the fluorination of diflufenican is dissolved in a mixed solution of a solvent and water, heated to 75 - 100 °C and kept warm for 2 h, then cooled to room temperature, filtered, and the precipitate is collected and dried to obtain potassium chloride with a content of more than 99%. The filtrate is collected by filtration and heated to 100 - 160 °C to remove the solvent and concentrate, and an aqueous solution of potassium fluoride is obtained, which is spray-dried to obtain highly active potassium fluoride with a content of more than 99%.