Purification method of sodium lauroyl sarcosinate

Abstract

The invention discloses a purification method of sodium lauroyl sarcosinate, and relates to the technical field of purification of compounds. The method comprises the following steps: mixing a sodium lauroyl sarcosinate sample to be purified with a first solvent to obtain a mixed system, and adding a second solvent for recrystallization when the temperature of the mixed system reaches room temperature; separating supernate and separated components, repeatedly dissolving the separated components, and then carrying out secondary recrystallization; and carrying out suction filtration and leaching on a product obtained by recrystallization. The purification method is simple and easy to implement, and chemical raw materials adopted in the purification method are simple, easy to obtain and low in cost; the purification method is mild in reaction condition and easy for large-scale production; according to the method provided by the invention, the sodium lauroyl sarcosinate with the purity exceeding 99% can be prepared at lower cost.

Description

Technical Field

[0001] This invention relates to the field of compound purification technology, and more specifically, to a method for purifying sodium lauroyl sarcosinate. Background Technology

[0002] Sodium lauroyl sarcosinate is an anionic surfactant with antimicrobial properties. It is considered an effective antimicrobial agent in topical formulations and has protein denaturing capabilities. It plays an important role in biology, pharmacology, and pharmaceutical science.

[0003] Most vendors on the market offer sodium lauroyl sarcosinate products with a purity of around 95%, and no specific characterization data for other impurities. However, the selection of high-purity sodium lauroyl sarcosinate products available on the market is limited, and most are quite expensive.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a purification method for sodium lauroyl sarcosinate, thereby simply preparing high-purity sodium lauroyl sarcosinate and achieving the required purification level.

[0006] This invention is implemented as follows: This invention provides a purification method for sodium lauroyl sarcosinate, comprising the following steps: mixing the sodium lauroyl sarcosinate sample to be purified with a first solvent to obtain a mixed system; after the temperature of the mixed system reaches room temperature, adding a second solvent for recrystallization; separating the supernatant and the precipitated components, repeating the dissolution of the precipitated components, and then performing a second recrystallization; filtering and rinsing the product obtained by recrystallization. The first solvent is selected from at least one of dichloromethane, acetonitrile, N,N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide and water; The second solvent is selected from at least one of acetonitrile and water; and the first solvent and the second solvent are different; The mass ratio of the sodium lauroyl sarcosinate sample to be purified to the first solvent is 1:10 to 1:1.

[0007] The present invention has the following beneficial effects: The purification method for sodium lauroyl sarcosinate provided by this invention is simple and easy to implement. The chemical raw materials used in the purification method are readily available and low in cost. The reaction conditions in the purification method are mild and easy to scale up for production. The method provided by this invention can prepare sodium lauroyl sarcosinate with a purity of over 99% at a low cost. Moreover, the purification method provided by this invention can maintain a high recovery rate and has extremely high application value, which can meet the requirements of high-purity compounds in special scenarios. Attached Figure Description

[0008] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 This is a diagram of the test results after purification. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0011] Sodium lauroyl sarcosinate, CAS No. 137-16-6; molecular formula is C 15 H 28 NO3Na.

[0012] This invention provides a purification method for sodium lauroyl sarcosinate, comprising the following steps: mixing the sodium lauroyl sarcosinate sample to be purified with a first solvent to obtain a mixed system; after the temperature of the mixed system reaches room temperature, adding a second solvent for recrystallization; separating the supernatant and the precipitated components, repeating the dissolution of the precipitated components, and then performing a second recrystallization; filtering and rinsing the product obtained by recrystallization. The first solvent is selected from at least one of dichloromethane, acetonitrile, N,N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide and water; The second solvent is selected from at least one of acetonitrile and water; and the first solvent and the second solvent are different; The mass ratio of the sodium lauroyl sarcosinate sample to be purified to the first solvent is 1:10 to 1:1.

[0013] The first solvent completely dissolves the sodium lauroyl sarcosinate sample, thus exhibiting extremely high solubility for sodium lauroyl sarcosinate, especially in water. As the temperature decreases to room temperature, the solubility of sodium lauroyl sarcosinate in the first solvent decreases. Upon adding the second solvent, although it also possesses some solubility for sodium lauroyl sarcosinate (though less than the first solvent), the two solvents compete to "steal" sodium lauroyl sarcosinate, causing it to crystallize. Repeated dissolution-recrystallization further improves the purity of the product.

[0014] The second solvent can also be called a poor solvent.

[0015] The sodium lauroyl sarcosinate sample to be purified, when mixed with the first solvent at the above-mentioned mass ratio, exhibits extremely high recovery rate and purification effect.

[0016] The mass ratio of the sodium lauroyl sarcosinate sample to be purified to the first solvent is, for example, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10.

[0017] In a preferred embodiment of the present invention, the second solvent is selected from acetonitrile, and the second solvent is added dropwise to the mixed system. When the second solvent is selected from acetonitrile, the precipitation effect of sodium lauroyl sarcosinate is better. If the second solvent is selected from solvents such as methanol, dichloromethane, and N,N-dimethylformamide, sodium lauroyl sarcosinate will not be able to precipitate.

[0018] In a preferred embodiment of the present invention, the first solvent is selected from acetonitrile, N,N-dimethylformamide, tetrahydrofuran, and water.

[0019] When the first solvent is water, purification has a lower preparation cost and yields sodium lauroyl sarcosinate with higher purity.

[0020] In a preferred embodiment of the present invention, the mass ratio of the sodium lauroyl sarcosinate sample to be purified to the first solvent is 1:5 to 1:1. At this mixing ratio, sodium lauroyl sarcosinate exhibits an extremely high yield.

[0021] In a preferred embodiment of the present invention, the mass ratio of the sodium lauroyl sarcosinate sample to be purified to the first solvent is 1:3 to 1:1.

[0022] In a preferred embodiment of the present invention, the mass ratio of the sodium lauroyl sarcosinate sample to be purified to the first solvent is 1:1.5 to 1:2. For example, the mixing ratio is 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2.

[0023] In a preferred embodiment of the present invention, the sodium lauroyl sarcosinate sample to be purified is dissolved in the first solvent at a temperature of 10-100°C. For example, this can be carried out at temperatures of 10-20°C, 10-30°C, 15-45°C, 20-55°C, 30-60°C, 40-70°C, 50-80°C, 55-90°C, and 50-100°C. Heating helps to accelerate the purification process. Those skilled in the art can choose to heat or not as needed; both methods can achieve the purification of sodium lauroyl sarcosinate, the only difference being the time required.

[0024] In a preferred embodiment of the present invention, the sodium lauroyl sarcosinate sample to be purified is mixed and dissolved with the first solvent at a temperature of 60-100°C, and stirring is performed during the dissolution process. For example, at 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 77°C, 78°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 92°C, 95°C, or 100°C.

[0025] In a preferred embodiment of the invention, after secondary recrystallization, the process further includes repeated dissolution and recrystallization. This repeated dissolution and recrystallization helps to further improve the purity of sodium lauroyl sarcosinate.

[0026] In a preferred embodiment of the present invention, the dissolution and recrystallization process is repeated 1 to 10 times, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 times.

[0027] In a preferred embodiment of the present invention, rinsing is performed using a second solvent.

[0028] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0029] Example 1 This embodiment provides a method for purifying sodium lauroyl sarcosinate.

[0030] (1) Dissolve 50 g of crude sodium lauroyl sarcosinate (commercially available product: Sangon Biotech, catalog number: A600486) in 150 mL of ultrapure water. Stir and dissolve the product at 80 °C. After the solid solvent becomes completely clear during the dissolution process, lower the system temperature to room temperature and continue stirring. Slowly add 1.5 L of acetonitrile under vigorous stirring for recrystallization. During this process, a white product continuously precipitates out.

[0031] (2) After the product has precipitated completely, the supernatant was poured off, and 150 mL of ultrapure water was added for secondary recrystallization. The mixture was stirred and dissolved under heating at 80°C. During the dissolution process, the solid solvent was observed to be completely clear. After the solid solvent was completely clear, the system temperature was lowered to room temperature and stirring was continued. 1.5 L of acetonitrile was slowly added dropwise under vigorous stirring for recrystallization. During this process, a white product was continuously precipitated. After recrystallization, the product was filtered using a vacuum funnel and washed with 200 mL of acetonitrile. After washing, the solid was collected and dried under vacuum to obtain a high-purity product. 42 g of ultrapure product was obtained after processing, with a purity ≥99% and a recovery rate of 84%.

[0032] Example 2 100 g of crude sodium lauroyl sarcosinate was dissolved in 200 mL of ultrapure water (primary solvent). The solution was heated to 80 °C with stirring until the solid solvent became completely clear. The system temperature was then lowered to room temperature with continued stirring. 2 L of acetonitrile (secondary solvent) was slowly added dropwise under vigorous stirring for recrystallization, during which a white product continuously precipitated. After the product had completely precipitated, the supernatant was discarded, and another 200 mL of ultrapure water (primary solvent) was added for a second recrystallization. The solution was heated to 80 °C with stirring until the solid solvent became completely clear. The system temperature was then lowered to room temperature with continued stirring. 2 L of acetonitrile (secondary solvent) was slowly added dropwise under vigorous stirring for recrystallization, during which a white product continuously precipitated. After recrystallization, the product was filtered using a vacuum funnel and washed with 300 mL of acetonitrile. After washing, the solid was collected and dried under vacuum to obtain a high-purity product. 91 g of ultrapure product was obtained after processing, with a purity ≥99% and a recovery rate of 91%.

[0033] Example 3 500 g of crude sodium lauroyl sarcosinate was dissolved in 1 L of ultrapure water. The solution was heated at 80°C with stirring until the solid solvent became completely clear. The system temperature was then lowered to room temperature with continued stirring. Under vigorous stirring, 10 L of acetonitrile was slowly added dropwise for recrystallization, during which a white product continuously precipitated. After the product had completely precipitated, the supernatant was discarded, and another 1 L of ultrapure water was added for a second recrystallization. The solution was heated at 80°C with stirring until the solid solvent became completely clear. The system temperature was then lowered to room temperature with continued stirring. Under vigorous stirring, 10 L of acetonitrile was slowly added dropwise for recrystallization, during which a white product continuously precipitated. After recrystallization, the product was filtered using a vacuum funnel and washed with 1 L of acetonitrile. After washing, the solid was collected and dried under vacuum to obtain a high-purity product. 462 g of ultrapure product was obtained, with a purity ≥99% and a recovery rate of 92.4%.

[0034] Example 4 1000 g of crude sodium lauroyl sarcosinate was dissolved in 1.5 L of ultrapure water. The solution was heated at 80°C with stirring until the solid solvent became completely clear. The system temperature was then lowered to room temperature with continued stirring. Under vigorous stirring, 15 L of acetonitrile was slowly added dropwise for recrystallization, during which a white product continuously precipitated. After the product had completely precipitated, the supernatant was discarded, and 1 L of ultrapure water was added for a second recrystallization. The solution was heated at 80°C with stirring until the solid solvent became completely clear. The system temperature was then lowered to room temperature with continued stirring. Under vigorous stirring, 15 L of acetonitrile was slowly added dropwise for recrystallization, during which a white product continuously precipitated. After recrystallization, the product was filtered using a vacuum funnel and washed with 1.5 L of acetonitrile. After washing, the solid was collected and dried under vacuum to obtain a high-purity product. 936 g of ultrapure product was obtained, with a purity ≥99% and a recovery rate of 93.6%.

[0035] Example 5 Compared to Example 2, the only difference was that the first solvent was dichloromethane; all other steps were the same. The result was that the product could not be completely dissolved, and the purity of the precipitated product after dissolution was 96%, showing no significant improvement, with a recovery rate of 30%.

[0036] Example 6 Compared with Example 2, the only difference is that the first solvent is N,N-dimethylformamide, and the other steps are the same.

[0037] The result was that after the product was dissolved, the purity of the precipitate was 95.3%, with no significant improvement, and the recovery rate was 10%.

[0038] Example 7 Compared to Example 2, the only difference was that the first solvent was tetrahydrofuran; all other steps were the same. The result was that after dissolution, the purity of the precipitated product was 96.1%, with no significant improvement, and the recovery rate was 12%.

[0039] Example 8 Compared to Example 2, the only difference is that the dissolution process was carried out with stirring at room temperature, without heating to 80°C. After 5 hours, the product was completely dissolved. The remaining steps were the same as in Example 2, and 90g of ultrapure product was obtained after processing, with a purity ≥99% and a recovery rate of 91%.

[0040] Comparative Example 1 Compared to Example 2, the only difference is that the second solvent is dichloromethane; the other steps are the same. Dichloromethane separates from the aqueous phase, preventing product precipitation.

[0041] Comparative Example 2 Compared with Example 2, the only difference is that the second solvent is methanol, and the other steps are the same.

[0042] Methanol is miscible with the first solvent and the product, so the product cannot precipitate out.

[0043] Comparative Example 3 Compared to Example 2, the only difference is that the second solvent is N,N-dimethylformamide; all other steps are the same. N,N-dimethylformamide is miscible with the first solvent and the product, preventing product precipitation.

[0044] Experimental Example 1 The sodium lauroyl sarcosinate obtained in Example 2 was analyzed for its product components.

[0045] 1. Trace analysis of metal ions was performed on the purified product using ion chromatography.

[0046] The steps of ion chromatography are as follows: (1) Weighing: Accurately weigh 1.0000 g of sample and place it in a 100 mL volumetric flask.

[0047] (2) Dissolution: Add 80 mL of ultrapure water and sonicate for 15-20 min (temperature ≤ 40℃, avoid thermal ion decomposition) to ensure complete dissolution of the sample.

[0048] (3) Volume adjustment: After cooling to room temperature, add ultrapure water to the mark, shake well, and obtain a 10 mg / mL mother solution.

[0049] (4) Dilution: Dilution according to the expected ion concentration (dilution 10 times to 1000 μg / mL, to avoid exceeding the upper limit of the standard curve).

[0050] (5) Filtration: Take 5 mL of the diluted solution and filter it through a 0.22 μm aqueous filter membrane into a sample bottle. Discard 1-2 mL of the initial filtrate (to avoid filter membrane contamination) and then proceed with the instrument.

[0051] (6) Injection conditions: KOH gradient of eluent: 10 mmol / L for 0~5 min; 10~40 mmol / L for 5~15 min, flow rate 1.0 mL / min.

[0052] 2. The purity of the purified product was analyzed and detected by high performance liquid chromatography.

[0053] (1) Weighing: Weigh 1.0000 g of sample using a 1 / 10,000 electronic balance and place it in a 100 mL volumetric flask (weighing error ≤ ±0.0002 g).

[0054] (2) Dissolution and extraction: Add 80 mL of the corresponding solvent (use ultrapure water for water-soluble components and methanol / water = 50:50 mixture for moderately polar components), and sonicate for 15~20 min (temperature ≤40℃ to avoid decomposition of heat-sensitive components) to ensure complete dissolution of the sample.

[0055] (3) Volume dilution: After cooling to room temperature, dilute to the mark with the extraction solvent, shake well, and obtain a 10 mg / mL stock solution; dilute according to the expected concentration (dilute 10 times to 500 μg / mL to avoid exceeding the upper limit of the standard curve).

[0056] (4) Filtration: Take 5 mL of the diluted solution and filter it through a 0.22 μm corresponding filter membrane (water system for aqueous solution, organic phase for organic solvent) into the sample bottle. Discard 1~2 mL of the initial filtrate (to avoid filter membrane contamination) and then proceed with the instrument.

[0057] (5) Injection conditions: C18 column (4.6 mm × 250 mm, 5 μm) + guard column; mobile phase methanol-water (60:40, v / v) or acetonitrile-water gradient (e.g. 0~10 min 30% acetonitrile → 10~20 min 30% → 80% acetonitrile; flow rate 1.0 mL / min).

[0058] 3. The purity of the weakly basic organic compounds in the product was determined by perchloric acid titration.

[0059] (1) Accurate weighing: Weigh 1.0000 g of sample using an electronic balance with a weight of 0.0002 g (weighing error ≤ ±0.0002 g) and place it in a dry 100 mL conical flask.

[0060] (2) Dissolving: Add 50 mL of glacial acetic acid, shake the conical flask, and if the sample is difficult to dissolve, extract by sonication for 15~20 min (temperature ≤30℃, avoid evaporation of glacial acetic acid) to ensure that the sample is completely dissolved (the solution is clear and there is no precipitate).

[0061] (3) Potentiometric titration Electrode preparation: Insert the glass electrode and the non-aqueous calomel electrode into the sample solution, connect them to the potentiometric titrator, and calibrate the electrodes. Titration: Set the titrator parameters (titration rate, endpoint determination method to "potential jump"), start automatic titration, and the instrument will automatically record the titration curve and the volume V1 consumed at the endpoint.

[0062] Figure 1 The graph shows the results of the product composition detection of sodium lauroyl sarcosinate obtained by purification in Example 2. The results show that the purity of sodium lauroyl sarcosinate is greater than 99.0%.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for purifying sodium lauroyl sarcosinate, characterized in that, The process includes the following steps: mixing the sodium lauroyl sarcosinate sample to be purified with a first solvent to obtain a mixed system; when the temperature of the mixed system reaches room temperature, adding a second solvent for recrystallization; separating the supernatant and the precipitated components, repeating the dissolution of the precipitated components, and then performing a second recrystallization; filtering and rinsing the product obtained from recrystallization. The first solvent is selected from at least one of dichloromethane, acetonitrile, N,N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide, and water; The second solvent is selected from at least one of acetonitrile and water; and the first solvent and the second solvent are different; The mass ratio of the sodium lauroyl sarcosinate sample to be purified to the first solvent is 1:10 to 1:

1.

2. The purification method for sodium lauroyl sarcosinate according to claim 1, characterized in that, The second solvent is selected from acetonitrile, and the second solvent is added dropwise to the mixture.

3. The purification method for sodium lauroyl sarcosinate according to claim 1, characterized in that, The first solvent is selected from acetonitrile, N,N-dimethylformamide, tetrahydrofuran, and water.

4. The purification method for sodium lauroyl sarcosinate according to claim 1, characterized in that, The mass ratio of the sodium lauroyl sarcosinate sample to be purified to the first solvent is 1:5 to 1:

1.

5. The purification method for sodium lauroyl sarcosinate according to claim 4, characterized in that, The mass ratio of the sodium lauroyl sarcosinate sample to be purified to the first solvent is 1:3 to 1:

1.

6. The purification method for sodium lauroyl sarcosinate according to claim 5, characterized in that, The mass ratio of the sodium lauroyl sarcosinate sample to be purified to the first solvent is 1:1.5 to 1:

2.

7. The purification method for sodium lauroyl sarcosinate according to claim 1, characterized in that, The sodium lauroyl sarcosinate sample to be purified was dissolved in the first solvent at 10-100℃.

8. The purification method for sodium lauroyl sarcosinate according to claim 7, characterized in that, The sodium lauroyl sarcosinate sample to be purified was mixed and dissolved with the first solvent at 60-100℃, and stirring was carried out during the dissolution process.

9. The purification method for sodium lauroyl sarcosinate according to claim 1, characterized in that, After secondary recrystallization, the process also includes repeated dissolution and recrystallization. Preferably, the dissolution and recrystallization process is repeated 1-10 times.

10. The purification method for sodium lauroyl sarcosinate according to claim 1, characterized in that, Rinse with a second solvent.

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