High-purity creatine monohydrate and preparation method thereof

Abstract

The invention relates to the field of preparation of guanidine or derivatives thereof, and particularly discloses high-purity creatine monohydrate and a preparation method thereof. The preparation method comprises the following steps: sequentially carrying out condensation reaction, acidolysis reaction and hydrolysis reaction on dimethyl sulfate and urea, cooling, crystallizing and filtering to obtain O-methylisourea hydrogen sulfate, and then reacting a sarcosine salt aqueous solution with the O-methylisourea hydrogen sulfate under the conditions that the temperature is 45-65 DEG C and the pH value is 10-12 to obtain the sarcosine salt. And performing post-treatment to obtain the high-purity creatine monohydrate. The preparation method has the advantages of being low in raw material cost, easy to transport and store and rich in source, byproducts in the reaction process are few, danger is low, the yield and purity are high, the industrial requirement is met, and the preparation method is suitable for large-scale industrial production.

Description

Technical Field

[0001] The present application relates to the field of preparation of guanidine or its derivatives, and more specifically, to a high-purity creatine monohydrate and a preparation method thereof. Background Art

[0002] Creatine, with the chemical formula C4H9N3O2, is a nitrogen-containing organic acid, also known as N-methylguanidinoacetic acid. This substance exists naturally in vertebrates, especially in skeletal muscle and brain tissue, where it can help provide energy for muscles and nerve cells. The main function of creatine is to increase the level of creatine phosphate in muscles, thereby increasing the regeneration rate of adenosine triphosphate (the main energy source for muscle contraction), delaying muscle fatigue, and enhancing explosive power and endurance.

[0003] In the field of sports and fitness, creatine is widely used as a nutritional supplement. Creatine supplementation can increase muscle strength, improve athletic performance, and help promote muscle growth and recovery. In addition, creatine can increase muscle absorption of water, thereby increasing muscle volume and quality. Creatine supplementation is particularly important for people who need to perform high-intensity exercise in a short period of time, such as weightlifters, sprinters, etc. In addition to its application in sports, creatine is also being studied in the medical field for possible therapeutic uses, such as muscle cramps, fatigue, multiple sclerosis, etc. As people's research on creatine deepens, I believe that new uses for creatine will continue to be discovered.

[0004] The traditional method for preparing creatine is to extract it from biological raw materials such as meat scraps. This method is not only expensive but also unhygienic. Therefore, creatine is currently synthesized by chemical methods, that is, by reacting aminonitrile with sarcosine to prepare creatine. However, sarcosine is an extremely expensive raw material, and the use of expensive sarcosine cannot achieve a satisfactory yield. Chinese patent CN1140707A discloses a method for preparing creatine or creatine monohydrate, aiming to obtain an economically significant yield and a higher purity. The method is to react aminonitrile with sodium sarcosinate or potassium sarcosinate in water or a mixed solution of water and an organic solvent. However, the product yield of the method is still relatively low, only 66.65%, and aminonitrile is extremely unstable and is easily hydrolyzed or self-polymerized in acid or alkali, resulting in special care during storage and preservation. Summary of the invention

[0005] In order to solve the above technical problems, the present application provides a high-purity creatine monohydrate and a preparation method thereof.

[0006] In the first aspect, the present application provides a method for preparing high-purity creatine monohydrate, which adopts the following technical scheme: A method for preparing high-purity creatine monohydrate comprises the following steps: Dimethyl sulfate and urea are subjected to condensation reaction, acidolysis reaction and hydrolysis reaction in sequence, and then cooled, crystallized and filtered to obtain O-methylisourea hydrogen sulfate. Then, a sarcosinate aqueous solution is reacted with O-methylisourea hydrogen sulfate at a temperature of 45-65° C. and a pH value of 10-12, and then post-processed to obtain high-purity creatine monohydrate.

[0007] Wherein, the sarcosinate aqueous solution is a sodium sarcosinate aqueous solution or a potassium sarcosinate aqueous solution.

[0008] By adopting the above technical scheme, the present application first uses dimethyl sulfate and urea to prepare O-methylisourea hydrogen sulfate, and then reacts O-methylisourea hydrogen sulfate with a sarcosinate aqueous solution as a reaction raw material under a certain temperature and pH value, and then prepares a purity of not less than 99.97% and a yield of more than 80% of creatine monohydrate through post-treatment. The preparation method of the present application has a higher yield than that of using aminonitrile as a reaction raw material, and the raw material is stable, not prone to polymerization, easy to transport and preserve, and meets the restrictions of economic conditions. In addition, due to the problems of large post-processing difficulty and long production cycle in industrial production of O-methylisourea hydrogen sulfate, its production cost is relatively high and the selling price is expensive. Therefore, compared with directly using commercially available O-methylisourea hydrogen sulfate, the present application selects urea with a lower price and sufficient source to react with dimethyl sulfate to prepare O-methylisourea hydrogen sulfate, and the O-methylisourea hydrogen sulfate obtained by the method has a higher content, and can be directly reacted with a sarcosinate aqueous solution without purification, which greatly reduces the production cost.

[0009] Specifically, at a temperature of 50-120° C., the dimethyl sulfate and urea are first reacted for 0.5-5 hours, sulfuric acid is then added to continue the reaction, and then water is added to perform a hydrolysis reaction.

[0010] Preferably, the reaction temperatures in the condensation reaction, acidolysis reaction and hydrolysis reaction are all 70-80°C.

[0011] Since a lower reaction temperature leads to a slower reaction process and an incomplete reaction, while a higher reaction temperature tends to cause the decomposition of O-methylisourea, thus affecting the product content, by adopting the above-mentioned technical scheme, the present application optimizes the reaction temperature in the condensation reaction, the acidolysis reaction and the hydrolysis reaction, so that the finally obtained O-methylisourea hydrogen sulfate has a higher content.

[0012] Preferably, the reaction time in the condensation reaction is 0.75-1 hour.

[0013] Since a shorter reaction time leads to a slower reaction process and an incomplete reaction, while a longer reaction time leads to an increase in by-products, which affects the product content, the present application optimizes the reaction time of the condensation reaction by adopting the above-mentioned technical scheme, so that the finally obtained O-methylisourea hydrogen sulfate has a higher content.

[0014] Optionally, the weight ratio of the sarcosinate aqueous solution to O-methylisourea hydrogen sulfate is 1:(1-1.2).

[0015] Preferably, the weight ratio of the sarcosinate aqueous solution to O-methylisourea hydrogen sulfate is 1:(1.1-1.15).

[0016] By adopting the above technical scheme, the present application further optimizes the ratio between the aqueous solution of sarcosinate and O-methylisourea hydrogen sulfate, which can not only make the reaction more fully proceed, but also make the residual amounts of sarcosinate and O-methylisourea hydrogen sulfate in the reaction solution after the reaction is completed lower, and finally the yield and purity of creatine monohydrate are higher.

[0017] Preferably, the reaction temperature of the sarcosinate aqueous solution and O-methylisourea hydrogen sulfate is 55-60°C.

[0018] By adopting the above technical scheme, the present application further optimizes the reaction temperature of the sarcosinate aqueous solution and O-methylisourea hydrogen sulfate, thereby further reducing the residual amounts of sarcosinate and O-methylisourea hydrogen sulfate in the reaction solution, thereby further improving the yield.

[0019] Preferably, the pH value of the reaction of the sarcosinate aqueous solution and O-methylisourea hydrogen sulfate is 11-11.5°C.

[0020] By adopting the above technical scheme, the present application further optimizes the reaction pH value of the sarcosinate aqueous solution and O-methylisourea hydrogen sulfate, thereby further reducing the residual amounts of sarcosinate and O-methylisourea hydrogen sulfate in the reaction solution, thereby further improving the yield.

[0021] Optionally, the reaction time of the sarcosinate aqueous solution and O-methylisourea hydrogen sulfate is 1-3 hours.

[0022] Preferably, the post-treatment is as follows: after the reaction is completed, hot steam is introduced into the reaction solution to precipitate crystals, which are then allowed to stand for centrifugal separation and washing, and then an alkaline complexing agent is added for recrystallization, followed by centrifugal separation, washing and drying.

[0023] By adopting the above technical solution, the present invention can further reduce the content of impurities in the product by adding an alkaline complexing agent during the recrystallization process, thereby further improving the purity of the product. In the present invention, the alkaline complexing agent is disodium ethylenediaminetetraacetate (EDTA-2Na).

[0024] In a second aspect, the present application provides a high-purity creatine monohydrate prepared by the above preparation method.

[0025] By adopting the above technical scheme, the creatine monohydrate prepared by the preparation method of the present application has the appearance of a white crystalline powder, a purity of ≥99.97%, a creatinine content of <100ppm, a sulfate content of ≤0.03%, a heavy metal content of <10ppm, a drying loss of ≤11.61%, a residue on ignition of ≤0.06%, and a fineness of <200 mesh.

[0026] In summary, this application has the following beneficial technical effects: 1. The preparation method of the present application has the advantages of low raw material cost, easy transportation and storage, and abundant sources, and has fewer by-products and lower danger during the reaction process, and has a high yield and purity, meets industrial requirements, and is suitable for large-scale industrial production; 2. The creatine monohydrate prepared by the preparation method of the present application has an appearance of white crystalline powder, a purity of ≥99.97%, a creatinine content of <100ppm, a sulfate content of ≤0.03%, a heavy metal content of <10ppm, a drying loss of ≤11.61%, an ignition residue of ≤0.06%, and a fineness of <200 mesh. DETAILED DESCRIPTION

[0027] The present application is further described in detail below with reference to the embodiments.

[0028] Material Source The raw materials used in this application are all commercially available products, including: Dimethyl sulfate, purchased from Shandong Hongcheng Chemical Co., Ltd., with a purity of 99%; Urea, purchased from Langfang Huinuo Fine Chemical Co., Ltd., with a purity of 99%; Since there is no significant difference between the effects of sodium sarcosinate aqueous solution and potassium sarcosinate aqueous solution as reaction raw materials, in the specific embodiment of the present application, sodium sarcosinate aqueous solution is used as an example for illustration. The sodium sarcosinate aqueous solution was purchased from Guangdong Yunxing Biotechnology Co., Ltd., and the content was 35%; Disodium ethylenediaminetetraacetic acid was purchased from Chengdu Wanxiang Hongrun Biotechnology Co., Ltd., with an active ingredient content of 99%.

[0029] Example 1.1 A method for preparing high-purity creatine monohydrate comprises the following steps: S1. 2kg of dimethyl sulfate and 1.2kg of urea were stirred and heated to 50°C for 0.5 hours, and then 0.8kg of 98% sulfuric acid was added at a temperature of 50°C for acidolysis reaction. The reaction time was 2 hours. After the acidolysis reaction was completed, 0.4kg of water was added at a temperature of 50°C for hydrolysis reaction. The reaction time was 2 hours, and then cooled to 0°C, white crystals were precipitated and filtered to obtain O-methylisourea hydrogen sulfate; S2. A sodium sarcosinate aqueous solution in a weight ratio of 1:1 and O-methylisourea hydrogen sulfate prepared in step S1 are reacted at a temperature of 45°C and a pH value of 10 for 1 hour. After the reaction, hot steam is introduced into the reaction solution for 35 minutes to precipitate crystals. The reaction solution is allowed to stand for 7 hours and then centrifuged. The mother liquor is dried and washed with distilled water until the pH value of the filtrate is ≤7.5, and then washed once with 95% ethanol. Water is then added and the temperature is raised to 45°C with stirring. The pH value is adjusted to 7.0 with 10% dilute sulfuric acid and then raised to 80°C. 0.3g of disodium ethylenediaminetetraacetate is added, and then the temperature is raised to 90°C. After stirring for 15 minutes, the filtrate is filtered off with suction, and the filtrate is cooled to 20°C to precipitate crystals. The filtrate is then centrifuged, washed once with distilled water and 95% ethanol, and vacuum dried at a temperature of 40°C and a pressure of 0.002MPa. Finally, the creatine monohydrate with high purity is obtained by dehydration at a temperature of 80°C.

[0030] Example 2.1 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S1, the reaction temperature is 70° C., and the rest is the same as Example 1.1.

[0031] Example 2.2 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S1, the reaction temperature is 80° C., and the rest is the same as Example 1.1.

[0032] Example 2.3 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S1, the reaction temperature is 100° C., and the rest is the same as Example 1.1.

[0033] Example 2.4 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S1, the reaction temperature is 120° C., and the rest is the same as Example 1.1.

[0034] Example 3.1 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S1, the condensation reaction time of dimethyl sulfate and urea is 0.75 hours, and the rest is the same as Example 1.1.

[0035] Example 3.2 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S1, the condensation reaction time of dimethyl sulfate and urea is 1 hour, and the rest is the same as Example 1.1.

[0036] Example 3.3 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S1, the condensation reaction time of dimethyl sulfate and urea is 2 hours, and the rest is the same as Example 1.1.

[0037] Example 3.4 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S1, the condensation reaction time of dimethyl sulfate and urea is 3 hours, and the rest is the same as Example 1.1.

[0038] Example 3.5 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S1, the condensation reaction time of dimethyl sulfate and urea is 5 hours, and the rest is the same as Example 1.1.

[0039] Example 4.1 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the weight ratio of the sodium sarcosinate aqueous solution to the O-methylisourea hydrogen sulfate prepared in step S1 is 1:1.05, and the rest is the same as Example 1.1.

[0040] Example 4.2 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the weight ratio of the sodium sarcosinate aqueous solution to the O-methylisourea hydrogen sulfate prepared in step S1 is 1:1.1, and the rest is the same as Example 1.1.

[0041] Example 4.3 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the weight ratio of the sodium sarcosinate aqueous solution to the O-methylisourea hydrogen sulfate prepared in step S1 is 1:1.15, and the rest is the same as Example 1.1.

[0042] Example 4.4 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the weight ratio of the sodium sarcosinate aqueous solution to the O-methylisourea hydrogen sulfate prepared in step S1 is 1:1.2, and the rest is the same as Example 1.1.

[0043] Example 5.1 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the reaction temperature of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 is 50° C., and the rest is the same as Example 1.1.

[0044] Example 5.2 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the reaction temperature of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 is 55° C., and the rest is the same as Example 1.1.

[0045] Example 5.3 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the reaction temperature of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 is 60° C., and the rest is the same as Example 1.1.

[0046] Example 5.4 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the reaction temperature of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 is 65° C., and the rest is the same as Example 1.1.

[0047] Example 6.1 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the pH value of the reaction between the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 is 10.5, and the rest is the same as Example 1.1.

[0048] Example 6.2 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the pH value of the reaction between the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 is 11, and the rest is the same as Example 1.1.

[0049] Example 6.3 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the pH value of the reaction between the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 is 11.5, and the rest is the same as Example 1.1.

[0050] Example 6.4 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the pH value of the reaction between the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 is 12, and the rest is the same as Example 1.1.

[0051] Example 7.1 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the reaction time of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 is 1.5 hours, and the rest is the same as Example 1.1.

[0052] Example 7.2 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the reaction time of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 is 2 hours, and the rest is the same as Example 1.1.

[0053] Example 7.3 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the reaction time of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 is 2.5 hours, and the rest is the same as Example 1.1.

[0054] Example 7.4 A method for preparing high-purity creatine monohydrate, which is different from Example 1.1 in that: in step S2, the reaction time of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 is 3 hours, and the rest is the same as Example 1.1.

[0055] Performance Testing The content of O-methylisourea hydrogen sulfate prepared in step S1 of the above-mentioned embodiments 1.1-3.5, and the yield and purity of creatine monohydrate prepared in step S2 were detected and calculated respectively. The results are shown in Table 1. Since the difference between embodiments 4.1-7.4 and embodiment 1.1 is only the change of process parameters in step S2, the content of O-methylisourea hydrogen sulfate prepared in step S1 of embodiments 4.1-7.4 is not repeated, and only the yield and purity of creatine monohydrate prepared in step S2 are recorded in Table 2.

[0056] Table 1 Performance test results of Examples 1.1-3.5 Table 2 Performance test results of Example 1.1 and Examples 4.1-7.4 As can be seen from Tables 1 and 2, the present application first uses dimethyl sulfate and urea to prepare O-methylisourea hydrogen sulfate, the content of which is not less than 80%, and the yield is greater than 35%, and then uses O-methylisourea hydrogen sulfate with a higher content to react with an aqueous solution of sodium sarcosinate, and then obtains creatine monohydrate through post-treatment, the purity of which is not less than 99.97%, and the yield is more than 80%. Experimental data show that compared with the yield of 66.65% in the prior art, the creatine monohydrate prepared in the present application has a higher yield and purity.

[0057] Among them, the difference between Examples 2.1-2.4 and Example 1.1 is that the reaction temperature of dimethyl sulfate and urea in step S1 is different. It can be seen from Table 1 that as the reaction temperature rises from 50°C to 120°C, the content and yield of O-methylisourea hydrogen sulfate show a trend of first increasing and then decreasing. The experimental data show that too low or too high a reaction temperature will affect the content and yield of O-methylisourea hydrogen sulfate. When the optimized reaction temperature is 70-80°C, the content and yield of O-methylisourea hydrogen sulfate can be maintained at a higher level, thereby further improving the yield of creatine monohydrate in step S2.

[0058] The difference between Examples 3.1-3.5 and Example 1.1 is that the time of the condensation reaction of dimethyl sulfate and urea in step S1 is different. As can be seen from Table 1, the condensation reaction of dimethyl sulfate and urea has begun to stop when the reaction time is 1 hour. Continuing to extend the condensation reaction time will increase the by-products, thereby reducing the content and yield of O-methylisourea hydrogen sulfate. Experimental data show that too short or too long a condensation reaction time will affect the content and yield of O-methylisourea hydrogen sulfate. When the condensation reaction time is optimized to 0.75-1 hour, the content and yield of O-methylisourea hydrogen sulfate can be maintained at a high level, thereby further improving the yield of creatine monohydrate in step S2.

[0059] The difference between Examples 4.1-4.4 and Example 1.1 is that the ratio between the sodium sarcosinate aqueous solution in step S2 and the O-methylisourea hydrogen sulfate prepared in step S1 is different. It can be seen from Table 1 that the ratio between the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 will have a certain impact on the yield and purity of creatine monohydrate. As the ratio of the two increases from 1:1 to 1:1.2, the yield of creatine monohydrate shows a trend of first increasing and then decreasing. Experimental data show that when the ratio of the two reaches 1:1.15 and then continues to increase, the yield of creatine monohydrate increases. The addition amount of O-methylisourea hydrogen sulfate will not only fail to further improve the yield of creatine monohydrate, but will increase the residual amount of O-methylisourea hydrogen sulfate in the reaction solution, increasing the recrystallization cost of the post-treatment process. Therefore, when the weight ratio of the sodium sarcosinate aqueous solution to the O-methylisourea hydrogen sulfate prepared in step S1 is further optimized to 1:(1.1-1.15), the reaction can be carried out more fully, and the residual amounts of sarcosinate and O-methylisourea hydrogen sulfate in the reaction solution after the reaction are lower, and the final yield and purity of creatine monohydrate are higher.

[0060] The difference between Examples 5.1-5.4 and Example 1.1 is that the reaction temperature of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 in step S2 is different. It can be seen from Table 1 that the reaction temperature of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 will have a certain influence on the yield and purity of creatine monohydrate. The experimental data show that when the reaction temperature of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 is further optimized to 55-60° C., the yield and purity of the finally prepared creatine monohydrate can be maintained at a high level.

[0061] The difference between Examples 6.1-6.4 and Example 1.1 is that the reaction pH values ​​of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in Step S1 in Step S2 are different. As can be seen from Table 1, as the reaction pH value increases from 10 to 12, the yield of creatine monohydrate shows a trend of first increasing and then decreasing. The experimental data show that when the reaction pH value of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in Step S1 is further optimized to 11-11.5° C., the yield and purity of the finally prepared creatine monohydrate can be maintained at a high level.

[0062] The difference between Examples 7.1-7.4 and Example 1.1 is that the reaction time of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 in step S2 is different. It can be seen from Table 1 that when the reaction time of the sodium sarcosinate aqueous solution and the O-methylisourea hydrogen sulfate prepared in step S1 is within 1-3 hours, the yield and purity of the finally prepared creatine monohydrate can be at a higher level. When the reaction time is 2 hours, compared with other reaction times, the yield of the obtained creatine monohydrate is the highest.

[0063] The embodiments of this specific implementation method are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing high-purity creatine monohydrate, characterized in that: The following steps are involved: Dimethyl sulfate and urea are subjected to condensation reaction, acidolysis reaction and hydrolysis reaction in sequence, and then cooled, crystallized and filtered to obtain O-methylisourea hydrogen sulfate. Then, a sarcosinate aqueous solution is reacted with O-methylisourea hydrogen sulfate at a temperature of 45-65° C. and a pH value of 10-12, and then post-processed to obtain high-purity creatine monohydrate.

2. The method for preparing high-purity creatine monohydrate according to claim 1, characterized in that: At a temperature of 50-120° C., the dimethyl sulfate and urea are first reacted for 0.5-5 hours, and then sulfuric acid is added to continue the reaction, and then water is added to perform a hydrolysis reaction.

3. The method for preparing high-purity creatine monohydrate according to claim 2, characterized in that: The reaction temperatures in the condensation reaction, acidolysis reaction and hydrolysis reaction are all 70-80°C.

4. The method for preparing high-purity creatine monohydrate according to claim 2, characterized in that: The reaction time in the condensation reaction is 0.75-1 hour.

5. The method for preparing high-purity creatine monohydrate according to claim 1, characterized in that: The weight ratio of the sarcosinate aqueous solution to O-methylisourea hydrogen sulfate is 1:(1.1-1.15).

6. The method for preparing high-purity creatine monohydrate according to claim 1, characterized in that: The reaction temperature of the sarcosinate aqueous solution and O-methylisourea hydrogen sulfate is 55-60°C.

7. The method for preparing high-purity creatine monohydrate according to claim 1, characterized in that: The pH value of the reaction between the sarcosinate aqueous solution and O-methylisourea hydrogen sulfate is 11-11.5°C.

8. The method for preparing high-purity creatine monohydrate according to claim 1, characterized in that: The reaction time of the sarcosinate aqueous solution and O-methylisourea hydrogen sulfate is 1-3 hours.

9. The method for preparing high-purity creatine monohydrate according to claim 1, characterized in that: The post-treatment specifically includes: after the reaction is completed, hot steam is introduced into the reaction solution to precipitate crystals, which are then centrifuged and washed after standing, and then an alkaline complexing agent is added for recrystallization, followed by centrifugation, washing and drying.

10. High-purity creatine monohydrate prepared by the preparation method of high-purity creatine monohydrate according to any one of claims 1 to 9.

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