A method for synthesizing potassium glycinate
By adding potassium salt and glycine to water and using acid-binding and water-removing agents such as cyclohexane at low temperature to remove water, the problem of preparing high-purity potassium glycinate under mild conditions has been solved, achieving efficient and low-cost preparation of potassium glycinate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NINGBO WILINCARE BIOTECH CO LTD
- Filing Date
- 2024-12-31
- Publication Date
- 2026-06-30
Abstract
Description
Technical Field
[0001] This invention relates to a method for preparing a chemical raw material, specifically a method for preparing potassium glycine, which belongs to the field of chemistry. Background Technology
[0002] Glycine, also known as aminoacetic acid, is one of the most important basic amino acids, widely used in food, pesticides, and pharmaceuticals. Glycine can be used as a food preservative to effectively extend shelf life and as a flavoring agent to enhance food flavor. It is also used in the production of plant growth regulators and organophosphate herbicides, and in the synthesis of antihypertensive drugs and stomach medications. Potassium glycinate, the potassium salt of glycine, not only possesses the above-mentioned functions but also exhibits good carbon dioxide absorption characteristics. Studies have shown that organic amines containing multiple amino groups in their structure have higher absorption capacity. Amino acid salts (AMA) are a novel CO2 absorbent. Compared to commonly used organic amines, amino acid salts are completely ionized in aqueous solutions, have low volatility after dissolving in water, and exhibit higher surface tension, while also possessing antioxidant degradation capabilities. Potassium glycinate, as a common amino acid salt, is inexpensive and has a fast CO2 absorption rate.
[0003] As society places increasing emphasis on environmental protection, people are paying more and more attention to carbon dioxide, which contributes to the greenhouse effect, and hope to achieve the resource utilization of carbon dioxide. The method of using potassium glycinate as a chemical adsorbent to capture carbon dioxide shows broad prospects.
[0004] Therefore, it is necessary to develop a production process for preparing high-purity potassium glycine under mild conditions. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to provide a method for preparing potassium glycinate. The preparation method involves a reaction under mild conditions and cleverly introduces a dehydrating agent during the preparation process, which further shortens the drying time required for the product and improves the stability of the product.
[0006] The technical solution adopted by this invention to solve the above-mentioned technical problems is as follows: The method for preparing potassium glycinate of this invention includes: adding potassium salt and glycine to water; adjusting the pH of the solution to 6.0–8.0 with an acid-binding agent; removing a portion of the water by azeotropic reaction with water using cyclohexane as a dehydrating agent at low temperature; adding the residue to a non-aqueous solvent of a certain concentration and temperature miscible with water to precipitate a solid; and obtaining the finished potassium glycinate product by centrifugation or filtration and drying. In this method, the dehydrating agent causes water to form an azeotrope with the dehydrating agent, and the water generated in the reaction is separated from the reaction system while refluxing at low temperature, thus greatly shortening the drying time required for potassium glycinate in the later stage. The potassium glycinate synthesized after adjustment with the acid-binding agent also has a high yield, low production cost, and low requirements for the purity of the raw materials glycine and potassium salt, but with high purity of the product potassium glycinate.
[0007] The present invention is implemented as follows: 1) Neutral potassium salt and glycine are added to water. During the reaction, the pH of the solution is adjusted to 6.0-8.0 with an acid-binding agent. After the reaction, part of the water in the reaction solution is removed by the dehydrating agent cyclohexane. The residue is added to a non-aqueous solvent of a certain temperature and concentration that is miscible with water to precipitate solid. After centrifugation or filtration and drying, potassium glycinate product is obtained.
[0008] 2) Add basic potassium salt and glycine to water to allow them to react. The reaction solution is then partially dehydrated using a dehydrating agent. The remaining product is added to a non-aqueous solvent of a certain temperature and concentration that is miscible with water, causing solid precipitation. After centrifugation or filtration and drying, potassium glycinate is obtained. The ratio of the added solvent (water) to glycine can be 1–50 / 1 (V / W). The ratio of the added dehydrating agent (cyclohexane) to glycine can also be 1–50 / 1 (V / W).
[0009] The potassium salt and glycine in the method are made from the following molar amounts of raw materials: 1 to 10 parts of glycine;
[0010] The method uses 1-11 parts of potassium salt; the non-aqueous solvent miscible with water at a certain temperature and concentration can be methanol, ethanol, acetone, or any mixture thereof, such as a mixture of 50% methanol and 50% acetone, or a mixture of 50% ethanol and acetone, etc.; the acid-binding agent is one or more of sodium hydroxide, potassium hydroxide, potassium carbonate, etc.; the concentration of the dehydrating agent cyclohexane is preferably 80%-100%. The concentration of the non-aqueous solvent is preferably 80%-100%, such as 95% ethanol, anhydrous ethanol, methanol, etc.
[0011] The potassium salt can be potassium hydroxide, potassium carbonate, or potassium bicarbonate, such as potassium hydroxide; the potassium glycine prepared by the method has a water content of 0% to 5%; the water-miscible non-aqueous solvent of the method can be used at temperatures ranging from -80°C to 40°C.
[0012] The method for preparing potassium glycinate can be as follows: add potassium salt to water, add glycine while stirring to dissolve, and allow the reaction to proceed. During the process, the pH can be adjusted by an acid-binding agent, and some water can be removed by a dehydrating agent. After filtration, the filtrate is added to anhydrous ethanol at -25℃ to 0℃ while stirring, left to stand, and the solid is taken, crushed, centrifuged (or filtered), and dried to obtain the product.
[0013] Compared with the prior art, the present invention has the following advantages:
[0014] (1) The present invention can realize the reaction process at a relatively low temperature of 70°C, which not only efficiently prepares potassium glycinate, but also produces a product with extremely low moisture content. By cleverly introducing a dehydrating agent during the reaction process, the drying time required for the product is further shortened, which not only significantly improves production efficiency, but also greatly enhances the stability of the product potassium glycinate.
[0015] (2) Furthermore, the present invention utilizes a water-removing agent, which effectively reduces the amount of non-aqueous solvents used in subsequent product processing. This measure not only optimizes the production process but also significantly enhances the environmental friendliness of the product. Detailed Implementation
[0016] The following embodiments are merely illustrative of the present invention, and the present invention is not limited to the contents of the following embodiments.
[0017] Example 1
[0018] Add 750 mL of purified water to a flask, and while stirring, add 56.1 g of potassium hydroxide. After it is completely dissolved, add 75 g of glycine (99% purity). After the addition is complete, react at 80 °C for 4 h, evaporate and concentrate to 1 / 3 of the volume, and dry the resulting viscous substance under vacuum at 50 °C for 30 days to obtain 77.3 g of potassium glycine, with a yield of 68.41%, a moisture content of 20.79%, and a purity of 75.71%.
[0019] Example 2
[0020] Add 750 mL of purified water to a flask, and while stirring, add 56.0 g of potassium hydroxide. After it is completely dissolved, add 75 g of glycine with a purity of 99%. After the addition is complete, react at 80 °C for 4 h. Then, add the reaction solution to 750 mL of 75% ethanol at -40 °C while stirring. A large amount of solid is formed. After the addition is complete, let it stand for 1 hour. Centrifuge, and dry under vacuum at 50 °C for 14 days to obtain 86.7 g of potassium glycine, with a yield of 76.72%, a moisture content of 0.79%, and a purity of 96.73%.
[0021] Example 3
[0022] Add 750 mL of purified water to a flask, and while stirring, add 56.1 g of potassium hydroxide. After it is completely dissolved, add 75 g of glycine with a purity of 80%. During the reaction at 70 °C for 4 h, remove approximately 75% of the solvent (water) with cyclohexane (80.0% purity). After filtration, add the resulting viscous substance to 750 mL of 75% ethanol (at -40 °C) while stirring. A large amount of solid is formed. After the addition is complete, let it stand for 1 hour. Centrifuge and dry under vacuum at 50 °C for 12 hours to obtain 101.1 g of potassium glycine, with a yield of 89.47%, a moisture content of 1.18%, and a purity of 96.62%.
[0023] Example 4
[0024] Add 1000 mL of purified water to a flask, and while stirring, add 174.3 g of potassium sulfate. After complete dissolution, add 75 g of glycine (99% purity). After the addition is complete, adjust the pH of the solution to 7.2 with potassium hydroxide. React at 70°C for 4 hours. During this process, titrate with 95% pure cyclohexane (a dehydrating agent) to remove approximately 90% of the solvent (water) (in this example, the initial water volume was 1000 mL, and approximately 900 mL of water was removed). After filtration, the filtrate is added to 750 mL of 75% ethanol (at -40°C) while stirring. A large amount of solid is generated, which is then dissolved again in 1000 mL of water. Evaporate to remove approximately 80% of the water. Filter again, and add the solid back to 750 mL of 75% ethanol (at -40°C) while stirring. Let stand for 1 hour. Centrifuge, and dry under vacuum at 50°C for 12 hours to obtain 110.9 g of potassium glycine, with a yield of 98.14%, 0.15% water content, and a purity of 99.11%.
[0025] Example 5
[0026] Add 750 mL of purified water to a flask, and while stirring, add 69.0 g of potassium carbonate. After complete dissolution, add 75 g of glycine (99% purity). After the addition is complete, adjust the pH of the solution to 7.5 with potassium hydroxide. React at 70°C for 4 hours. During this process, remove approximately 75% of the solvent (water) using 99% pure cyclohexane as a dehydrating agent. Filter the mixture and add the resulting viscous substance to 750 mL of 99% ethanol (at -40°C) while stirring. A large amount of solid is formed. After the addition is complete, let stand for 1 hour. Centrifuge and dry under vacuum at 50°C for 12 hours to obtain 107.1 g of potassium glycine, with a yield of 94.8%, a moisture content of 0.19%, and a purity of 99.63%.
[0027] Example 6
[0028] Add 200 mL of purified water to a flask, and while stirring, add 69.0 g of potassium carbonate. After complete dissolution, add 75 g of glycine (99% purity). Adjust the pH of the solution to 7.0 with potassium hydroxide. React at 70°C for 4 hours. During this process, titrate with 99% pure cyclohexane (a dehydrating agent) to remove approximately 90% of the solvent (water) (in this example, the initial water volume was 200 mL, and approximately 180 mL was removed). Add the resulting viscous substance to 750 mL of 99% ethanol (at -40°C) while stirring; a large amount of solid is formed. After the addition is complete, let stand for 1 hour. Centrifuge and dry under vacuum at 50°C for 12 hours to obtain 109.7 g of potassium glycine, with a yield of 97.1%, a moisture content of 0.20%, and a purity of 99.67%.
[0029] Example 7
[0030] Add 750 mL of purified water to a flask, and while stirring, add 69.0 g of potassium carbonate. After complete dissolution, add 75 g of glycine (99% purity). Adjust the pH of the solution to 7.0 with potassium hydroxide. React at 70°C for 4 hours. During this process, remove approximately 90% of the solvent (water) using 99% pure cyclohexane as a dehydrating agent. Add the resulting viscous substance to 750 mL of 99% methanol (at -20°C) while stirring; a large amount of solid is formed. After the addition is complete, let stand for 1 hour. Centrifuge and dry under vacuum at 50°C for 12 hours to obtain 105.4 g of potassium glycine, with a yield of 93.3%, moisture content of 0.22%, and purity of 99.70%.
[0031] Example 8
[0032] Add 750 mL of purified water to a flask, and while stirring, add 69.0 g of potassium carbonate. After complete dissolution, add 75 g of glycine (99% purity). Adjust the pH of the solution to 7.0 with potassium hydroxide. React at 70°C for 4 hours. During this process, remove approximately 90% of the solvent (water) using 99% pure cyclohexane as a dehydrating agent. Add the resulting viscous substance to 750 mL of 75% acetone (at -40°C) while stirring; a large amount of solid will form. After the addition is complete, let stand for 1 hour. Centrifuge and dry under vacuum at 50°C for 12 hours to obtain 104.1 g of potassium glycine, with a yield of 93.2%, 0.15% moisture content, and a purity of 98.98%.
[0033] The product determination results of Examples 1-8 are shown in Table 1 below:
[0034] Table 1
[0035] Yield / % Moisture / % purity / % Example 1 68.41 20.79 75.71 Example 2 76.72 0.79 96.73 Example 3 89.47 1.18 96.62 Example 4 98.14 0.15 99.11 Example 5 94.8 0.19 99.63 Example 6 97.1 0.20 99.67 Example 7 93.3 0.22 99.70 Example 8 93.2 0.15 98.98
[0036] Example 1 involved a conventional reaction with a long drying time, resulting in low product yield and low purity. Example 2, compared to Example 1, removed most of the water and purified the product by adding ethanol, resulting in a low product yield but significantly improved purity. Example 3 involved adding a dehydrating agent to remove most of the water during the reaction, greatly reducing the product drying time. Examples 4-8 involved removing most of the water with a dehydrating agent while adjusting the pH during the reaction with an acid-binding agent, resulting in high yield and high purity under low temperature conditions.
Claims
1. A process for the preparation of potassium glycinate, characterized in that: Potassium salt and glycine are added to water, and the pH of the solution is adjusted to 6.0-8.0 with an acid-binding agent. The reaction solution is passed through a dehydrating agent, cyclohexane, to remove some of the water. The residue is added to a non-aqueous solvent of a certain concentration and temperature that is miscible with water to precipitate a solid. After centrifugation or filtration and drying, potassium glycinate is obtained. The potassium salt and glycine are made from the following molar parts of raw materials: 1-10 parts of glycine and 1-11 parts of potassium salt.
2. The process for the preparation of potassium glycinate according to claim 1, characterized in that: The water-miscible non-aqueous solvent is one of methanol, ethanol, acetone, or any mixture thereof.
3. The process for the preparation of potassium glycinate according to claim 1, characterized in that: The concentration of the non-aqueous solvent is 80% to 100%.
4. The process for the preparation of potassium glycinate according to claim 1, characterized in that: The potassium salt is one or more of potassium chloride, potassium sulfate, potassium hydroxide, potassium carbonate, and potassium bicarbonate.
5. The process for the preparation of potassium glycinate according to claim 1, characterized in that: The glycine in question has a purity of 80% to 100%.
6. The process for the preparation of potassium glycinate according to claim 1, characterized in that: The acid-binding agent is one or more of sodium hydroxide, potassium hydroxide, potassium carbonate, etc.
7. The process for the preparation of potassium glycinate according to claim 1, characterized in that: The dehydrating agent, cyclohexane, has a purity of 80% to 100%.
8. The process for the preparation of potassium glycinate according to claim 1, characterized in that: The water content of the reaction solution is 75% to 100%.
9. The process for the preparation of potassium glycinate according to claim 1, characterized in that: Add 1000 mL of purified water to a flask, and while stirring, add 174.3 g of potassium sulfate. After it is completely dissolved, add 75 g of glycine (99% purity). After the addition is complete, adjust the pH of the solution to 7.2 with potassium hydroxide. React at 70°C for 4 hours. During this process, remove 90% of the water using 95% pure cyclohexane as a dehydrating agent. After filtration, add the filtrate to 750 mL of 75% ethanol (at -40°C) while stirring. A large amount of solid is formed, which is then dissolved again in 1000 mL of water. Evaporate to remove 80% of the water. Filter again, and add the solid back to 750 mL of 75% ethanol (at -40°C) while stirring. Let stand for 1 hour. Centrifuge, and dry under vacuum at 50°C for 12 hours to obtain 110.9 g of potassium glycine, with a yield of 98.14%, a moisture content of 0.15%, and a purity of 99.11%.
10. The process for the preparation of potassium glycinate according to claim 1, characterized in that: Add 200 mL of purified water to a flask, and add 69.0 g of potassium carbonate while stirring. After it is completely dissolved, add 75 g of glycine with a purity of 99%. After the addition is complete, adjust the pH of the solution to 7.0 with potassium hydroxide. React at 70 °C for 4 h. During the reaction, remove about 90% of the water with cyclohexane with a purity of 99%. Add the resulting viscous substance to 750 mL of 99% ethanol at -40 °C while stirring. A large amount of solid is generated. After the addition is complete, let it stand for 1 hour. Centrifuge and dry under vacuum at 50 °C for 12 hours to obtain 109.7 g of potassium glycine, with a yield of 97.1%, a moisture content of 0.20%, and a purity of 99.67%.