Preparation method of high-purity magnesium glycerophosphate

Abstract

The invention discloses a preparation method of high-purity magnesium glycerophosphate, and belongs to the technical field of organic salt synthesis. According to the method, glycerol and phosphoric acid which are low in cost and easy to obtain are taken as starting raw materials, esterification reaction is firstly carried out under the action of a specific catalyst to generate glycerophosphate, then a magnesium source is added for salt forming reaction, and a high-purity magnesium glycerophosphate product is finally obtained by regulating and controlling the type of the catalyst, the reaction temperature, the pH value and the reaction time and combining a step-by-step purification process. The method has the advantages of easily available raw materials, recyclable catalyst, mild reaction conditions, simple process flow, high product purity, no generation of harmful impurities and the like, solves the problems of high raw material cost, complex process, difficulty in ensuring the product purity and the like in the existing magnesium glycerophosphate synthesis method, and is suitable for industrial large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of organic salt synthesis technology, specifically relating to a method for preparing high-purity magnesium glycerophosphate. Background Technology

[0002] Magnesium glycerophosphate is an important organophosphate with good water solubility and biocompatibility, and it has wide applications in the food, feed, and pharmaceutical industries. In the food industry, it can be used as a nutritional fortifier to supplement magnesium and phosphorus; in the feed industry, it can improve the growth performance and immunity of livestock and poultry; and in the pharmaceutical field, it can be used as an antacid, a laxative, and a drug intermediate for treating diseases such as osteoporosis.

[0003] Currently, the main methods for synthesizing magnesium glycerophosphate are as follows: 1. A metathesis reaction using sodium glycerophosphate and magnesium chloride as raw materials is carried out. This method requires the preparation of sodium glycerophosphate first, and then reacting it with magnesium chloride to produce magnesium glycerophosphate and sodium chloride. After the reaction, multiple washing is required to remove sodium chloride impurities. The process is complex, the product yield is low, and harmful impurities such as chloride ions are easily introduced, affecting product quality.

[0004] 2. Using glycerol and phosphorus trichloride as raw materials, glycerol phosphate is first synthesized, and then reacted with magnesium oxide to produce magnesium glycerol phosphate. The phosphorus trichloride used in this method has strong corrosiveness and toxicity. Hydrogen chloride gas is generated during the reaction process, which requires high-end equipment and is prone to causing environmental pollution. At the same time, chloride ions are easily left in the product.

[0005] 3. A reaction is carried out using glycerol and ammonium phosphate as raw materials to produce glycerophosphate and ammonia. A magnesium source is then added for neutralization. This method produces ammonia during the reaction, which needs to be recovered and treated, increasing the process cost. In addition, the reaction conditions are relatively harsh, and the purity of the product is difficult to guarantee.

[0006] The existing synthesis methods described above suffer from problems such as high raw material costs, complex processes, demanding equipment requirements, easy generation of harmful impurities, and low product purity, which limit the large-scale industrial production and application of magnesium glycerophosphate. Therefore, developing a method that uses readily available raw materials, has a simple process, is environmentally friendly, and can produce high-purity magnesium glycerophosphate is of significant practical importance. Summary of the Invention

[0007] To address the shortcomings of existing methods for synthesizing magnesium glycerophosphate, the present invention aims to provide a method for preparing high-purity magnesium glycerophosphate. This method uses inexpensive and readily available glycerol and phosphoric acid as starting materials, and achieves efficient synthesis of magnesium glycerophosphate by optimizing reaction conditions and process steps, resulting in a high-purity product. Furthermore, the entire process is environmentally friendly and suitable for industrial production.

[0008] The technical solution of the present invention is as follows: A method for preparing high-purity magnesium glycerophosphate, characterized by comprising the following steps: (1) Esterification reaction: Glycerol and phosphoric acid are added to a reaction vessel in a certain molar ratio, a catalyst is added, and esterification reaction is carried out under specific temperature and reduced pressure conditions to produce crude glycerol phosphate ester; (2) Neutralization reaction: Slowly add magnesium source to the crude glycerophosphate obtained in step (1), control the reaction temperature and pH value, carry out neutralization reaction, and obtain magnesium glycerophosphate reaction solution; (3) Purification treatment: The glycerol magnesium phosphate reaction solution obtained in step (2) is filtered to remove insoluble impurities, and then activated carbon is added to the filtrate for decolorization. After the decolorization treatment is completed, the activated carbon is removed by filtration. (4) Crystallization and drying: The filtrate purified in step (3) is concentrated under reduced pressure until a crystal film appears in the solution. Then, a low-carbon alcohol solvent is added for alcohol precipitation and crystallization. After crystallization, the crystals are separated by centrifugation and dried under vacuum to obtain the glycerol magnesium phosphate product.

[0009] In the above technical solution, the molar ratio of glycerol to phosphoric acid in step (1) is 1:1.05~1.2.

[0010] In the above technical solution, the catalyst in step (1) is SO4. 2- / ZrO2、SO4 2- / TiO2、SO4 2- / Fe2O3、SO4 2- One or more of / TiO2-ZrO2 are selected, and the amount of catalyst added is 0.5~2.0% of the mass of glycerol.

[0011] In the above technical solution, the esterification reaction temperature in step (1) is 80~120 ℃, the reduced pressure condition is 0.05~0.1 MPa, and the reaction time is 2~8 h.

[0012] In the above technical solution, the magnesium source in step (2) is one or more of magnesium oxide, magnesium hydroxide or magnesium carbonate, and the molar ratio of glycerol to magnesium source is 1:1.0~1.6.

[0013] In the above technical solution, the neutralization reaction temperature in step (2) is 50~80 ℃, the reaction time is 1~5h, and the pH value is controlled at 6.0~9.0 during the reaction.

[0014] In the above technical solution, the amount of activated carbon added in step (3) is 0.3~1.0% of the mass of the filtrate, the decolorization temperature is 40~60 ℃, and the decolorization time is 0.5~2.5 h.

[0015] In the above technical solution, the low-carbon alcohol solvent in step (4) is one or more of n-butanol, isopropanol, methanol, and ethanol.

[0016] In the above technical solution, the pressure of vacuum concentration in step (4) is 0.01~0.05 MPa, the concentration temperature is 60~80 ℃; the temperature of vacuum drying is 50~70 ℃, and the drying time is 4~8 h.

[0017] In the above technical solution, the purity of the glycerophosphate magnesium is ≥99.5%, and the heavy metal content (as Pb) is ≤0.0005%.

[0018] This invention provides a method for preparing high-purity magnesium glycerophosphate. Compared with the prior art, this invention has the following advantages: 1. Raw materials are readily available and low in cost: This invention uses glycerol and phosphoric acid as starting materials. Glycerol is a byproduct of biodiesel production, which is widely available and inexpensive. Phosphoric acid is also a commonly used basic raw material in the chemical industry and is easily obtained, significantly reducing raw material costs and facilitating large-scale industrial production. In addition, the solid acid catalyst used not only has excellent catalytic activity but also good recyclability.

[0019] 2. Mild reaction conditions: The esterification reaction temperature is controlled at 80~120 ℃, and the neutralization reaction temperature is controlled at 50~80 ℃, both of which are relatively mild reaction temperatures. No high temperature and high pressure conditions are required, and the equipment requirements are low, which reduces equipment investment and energy consumption in the production process.

[0020] 3. Simple process flow: The entire synthesis process includes only four main steps: esterification, neutralization, purification, crystallization and drying. It is easy to operate and control, and does not require complex separation and purification equipment and steps, which reduces process steps and improves production efficiency.

[0021] 4. High product purity and absence of harmful impurities: By optimizing process parameters such as catalyst type and dosage, reaction temperature, and pH value, and by using purification methods such as activated carbon decolorization, multiple filtrations, and crystallization, the introduction of harmful impurities (such as chloride ions and heavy metals) is effectively avoided. The prepared magnesium glycerophosphate has a purity of ≥99.5% and a heavy metal content (as Pb) of ≤0.0005%, meeting the requirements of high-purity magnesium glycerophosphate in the food, feed, and pharmaceutical industries.

[0022] 5. Environmentally friendly: No toxic or harmful gases (such as hydrogen chloride, ammonia, etc.) are generated during the reaction process of this invention. The small amount of filter residue (such as insoluble impurities and activated carbon) produced can be treated harmlessly, causing no pollution to the environment and meeting the requirements of green chemical production. Detailed Implementation

[0023] The present invention will be further illustrated below with reference to the embodiments, but the scope of protection of the present invention is not limited to the scope described in the embodiments.

[0024] Example 1 In a 500 mL three-necked flask equipped with a stirrer, thermometer, reflux condenser, and water separator, 184 g (2 mol) of glycerol and 235.2 g (2.4 mol) of phosphoric acid (the molar ratio of glycerol to phosphoric acid was 1:1.2) were added, followed by 1.84 g of H2SO4 (1% of the mass of glycerol). The stirring was started, and the temperature was gradually increased to 120 °C under a pressure of 0.05 MPa for esterification reaction, which lasted for 6 h.

[0025] After the esterification reaction is completed, the reaction system is cooled to 60 °C, and 20% magnesium hydroxide suspension is slowly added dropwise until the pH value of the reaction system is between 7 and 8. Stirring is continued to carry out the neutralization reaction, and the reaction time is 2 h.

[0026] After the neutralization reaction, the reaction system was filtered to remove insoluble impurities, yielding a clear filtrate. 5 g of activated carbon was then added to the filtrate, and the temperature was gradually raised to 50 °C. The mixture was stirred and decolorized for 1 h, then filtered again to remove the activated carbon, yielding a purified filtrate. The purified filtrate was transferred to a rotary evaporator and concentrated under reduced pressure at 0.01 MPa and 70 °C until a crystalline film appeared. Finally, ethanol was added to the concentrate for alcohol precipitation and crystallization. After crystallization, the crystals were separated by centrifugation and placed in a vacuum drying oven at 60 °C for 6 h to obtain 204.1 g of magnesium glycerol phosphate product, with a yield of 52.5%. Testing showed that the product purity was 99.5%, and the heavy metal content (as Pb) was less than 0.0005%.

[0027] Example 2 In a 500 mL three-necked flask equipped with a stirrer, thermometer, reflux condenser, and water separator, add 184 g (2 mol) of glycerol and 235.2 g (2.4 mol) of phosphoric acid (the molar ratio of glycerol to phosphoric acid is 1:1.2), then add 1.84 g of SO4. 2- With ZrO2 (1% of glycerol by mass), start stirring and gradually increase the temperature to 120 °C under a pressure of 0.05 MPa for esterification reaction for 6 h.

[0028] After the esterification reaction is completed, the reaction system is cooled to 60 °C, and 20% magnesium hydroxide suspension is slowly added dropwise until the pH value of the reaction system is between 7 and 8. Stirring is continued to carry out the neutralization reaction, and the reaction time is 2 h.

[0029] After the neutralization reaction, the reaction system was filtered to remove insoluble impurities, yielding a clear filtrate. 5 g of activated carbon was then added to the filtrate, and the temperature was gradually raised to 50 °C. The mixture was stirred and decolorized for 1 h, then filtered again to remove the activated carbon, yielding a purified filtrate. The purified filtrate was transferred to a rotary evaporator and concentrated under reduced pressure at 0.01 MPa and 70 °C until a crystalline film appeared. Finally, ethanol was added to the concentrate for alcohol precipitation and crystallization. After crystallization, the crystals were separated by centrifugation and placed in a vacuum drying oven at 60 °C for 6 h to obtain 330.1 g of magnesium glycerophosphate product, with a yield of 84.9%. Testing showed that the product purity was 99.6%, and the heavy metal content (as Pb) was less than 0.0003%.

[0030] Example 3 In a 500 mL three-necked flask equipped with a stirrer, thermometer, reflux condenser, and water separator, add 184 g (2 mol) of glycerol and 235.2 g (2.4 mol) of phosphoric acid (the molar ratio of glycerol to phosphoric acid is 1:1.2), then add 1.84 g of SO4. 2- With TiO2 (1% of glycerol by mass), start stirring and gradually increase the temperature to 120 °C under a pressure of 0.05 MPa for esterification reaction for 6 h.

[0031] After the esterification reaction is completed, the reaction system is cooled to 60 °C, and 20% magnesium hydroxide suspension is slowly added dropwise until the pH value of the reaction system is between 7 and 8. Stirring is continued to carry out the neutralization reaction, and the reaction time is 2 h.

[0032] After the neutralization reaction, the reaction system was filtered to remove insoluble impurities, yielding a clear filtrate. 5 g of activated carbon was then added to the filtrate, and the temperature was gradually raised to 50 °C. The mixture was stirred and decolorized for 1 h, then filtered again to remove the activated carbon, yielding a purified filtrate. The purified filtrate was transferred to a rotary evaporator and concentrated under reduced pressure at 0.01 MPa and 70 °C until a crystalline film appeared. Finally, ethanol was added to the concentrate for alcohol precipitation and crystallization. After crystallization, the crystals were separated by centrifugation and placed in a vacuum drying oven at 60 °C for 6 h to obtain 360.0 g of magnesium glycerol phosphate product, with a yield of 92.6%. Testing showed that the product purity was 99.7%, and the heavy metal content (as Pb) was less than 0.0003%.

[0033] Example 4 In a 500 mL three-necked flask equipped with a stirrer, thermometer, reflux condenser, and water separator, add 184 g (2 mol) of glycerol and 235.2 g (2.4 mol) of phosphoric acid (the molar ratio of glycerol to phosphoric acid is 1:1.2), then add 1.84 g of SO4 that has been recycled six times. 2- With TiO2 (1% of glycerol by mass), start stirring and gradually increase the temperature to 120 °C under a pressure of 0.05 MPa for esterification reaction for 6 h.

[0034] After the esterification reaction is completed, the reaction system is cooled to 60 °C, and 20% magnesium hydroxide suspension is slowly added dropwise until the pH value of the reaction system is between 7 and 8. Stirring is continued to carry out the neutralization reaction, and the reaction time is 2 h.

[0035] After the neutralization reaction, the reaction system was filtered to remove insoluble impurities, yielding a clear filtrate. 5 g of activated carbon was then added to the filtrate, and the temperature was gradually raised to 50 °C. The mixture was stirred and decolorized for 1 h, then filtered again to remove the activated carbon, yielding a purified filtrate. The purified filtrate was transferred to a rotary evaporator and concentrated under reduced pressure at 0.01 MPa and 70 °C until a crystalline film appeared. Finally, ethanol was added to the concentrate for alcohol precipitation and crystallization. After crystallization, the crystals were separated by centrifugation and placed in a vacuum drying oven at 60 °C for 6 h to obtain 346.8 g of magnesium glycerol phosphate product, with a yield of 89.2%. Testing showed that the product purity was 99.8%, and the heavy metal content (as Pb) was less than 0.0003%.

[0036] Example 5 In a 500 mL three-necked flask equipped with a stirrer, thermometer, reflux condenser, and water separator, add 184 g (2 mol) of glycerol and 235.2 g (2.4 mol) of phosphoric acid (the molar ratio of glycerol to phosphoric acid is 1:1.2), then add 1.84 g of SO4. 2- With Fe2O3 (1% of glycerol by mass), stirring was started, and the temperature was gradually increased to 120 °C under a pressure of 0.05 MPa for esterification reaction, and the reaction time was 6 h.

[0037] After the esterification reaction is completed, the reaction system is cooled to 60 °C, and 20% magnesium hydroxide suspension is slowly added dropwise until the pH value of the reaction system is between 7 and 8. Stirring is continued to carry out the neutralization reaction, and the reaction time is 2 h.

[0038] After the neutralization reaction, the reaction system was filtered to remove insoluble impurities, yielding a clear filtrate. 5 g of activated carbon was then added to the filtrate, and the temperature was gradually raised to 50 °C. The mixture was stirred and decolorized for 1 h, then filtered again to remove the activated carbon, yielding a purified filtrate. The purified filtrate was transferred to a rotary evaporator and concentrated under reduced pressure at 0.01 MPa and 70 °C until a crystalline film appeared. Finally, ethanol was added to the concentrate for alcohol precipitation and crystallization. After crystallization, the crystals were separated by centrifugation and placed in a vacuum drying oven at 60 °C for 6 h to obtain 318.2 g of magnesium glycerol phosphate product, with a yield of 81.8%. Testing showed that the product purity was 99.5%, and the heavy metal content (as Pb) was less than 0.0003%.

[0039] Example 6 In a 500 mL three-necked flask equipped with a stirrer, thermometer, reflux condenser, and water separator, add 184 g (2 mol) of glycerol and 235.2 g (2.4 mol) of phosphoric acid (the molar ratio of glycerol to phosphoric acid is 1:1.2), then add 1.84 g of SO4. 2- With TiO2-ZrO2 (1% of glycerol by mass), start stirring and gradually increase the temperature to 120 °C under a pressure of 0.05 MPa for esterification reaction for 6 h.

[0040] After the esterification reaction is completed, the reaction system is cooled to 60 °C, and 20% magnesium hydroxide suspension is slowly added dropwise until the pH value of the reaction system is between 7 and 8. Stirring is continued to carry out the neutralization reaction, and the reaction time is 2 h.

[0041] After the neutralization reaction, the reaction system was filtered to remove insoluble impurities, yielding a clear filtrate. 5 g of activated carbon was then added to the filtrate, and the temperature was gradually raised to 50 °C. The mixture was stirred and decolorized for 1 h, then filtered again to remove the activated carbon, yielding a purified filtrate. The purified filtrate was transferred to a rotary evaporator and concentrated under reduced pressure at 0.01 MPa and 70 °C until a crystalline film appeared. Finally, ethanol was added to the concentrate for alcohol precipitation and crystallization. After crystallization, the crystals were separated by centrifugation and placed in a vacuum drying oven at 60 °C for 6 h to obtain 352.2 g of magnesium glycerol phosphate product, with a yield of 90.6%. Testing showed that the product purity was 99.6%, and the heavy metal content (as Pb) was less than 0.0003%.

[0042] Example 7 In a 500 mL three-necked flask equipped with a stirrer, thermometer, reflux condenser, and water separator, add 184 g (2 mol) of glycerol and 235.2 g (2.4 mol) of phosphoric acid (the molar ratio of glycerol to phosphoric acid is 1:1.2), then add 1.84 g of SO4. 2- With TiO2 (1% of glycerol by mass), start stirring and gradually increase the temperature to 120 °C under a pressure of 0.05 MPa for esterification reaction for 6 h.

[0043] After the esterification reaction is completed, the reaction system is cooled to 60 °C, and 20% magnesium oxide suspension is slowly added dropwise until the pH value of the reaction system is between 7 and 8. Stirring is continued to carry out the neutralization reaction, and the reaction time is 2 h.

[0044] After the neutralization reaction, the reaction system was filtered to remove insoluble impurities, yielding a clear filtrate. 5 g of activated carbon was then added to the filtrate, and the temperature was gradually raised to 50 °C. The mixture was stirred and decolorized for 1 h, then filtered again to remove the activated carbon, yielding a purified filtrate. The purified filtrate was transferred to a rotary evaporator and concentrated under reduced pressure at 0.01 MPa and 70 °C until a crystalline film appeared. Finally, ethanol was added to the concentrate for alcohol precipitation and crystallization. After crystallization, the crystals were separated by centrifugation and placed in a vacuum drying oven at 60 °C for 6 h to obtain 340.7 g of magnesium glycerophosphate product, with a yield of 87.6%. Testing showed that the product purity was 99.8%, and the heavy metal content (as Pb) was less than 0.0003%.

[0045] Example 8 In a 500 mL three-necked flask equipped with a stirrer, thermometer, reflux condenser, and water separator, add 184 g (2 mol) of glycerol and 235.2 g (2.4 mol) of phosphoric acid (the molar ratio of glycerol to phosphoric acid is 1:1.2), then add 1.84 g of SO4. 2- With TiO2 (1% of glycerol by mass), start stirring and gradually increase the temperature to 120 °C under a pressure of 0.05 MPa for esterification reaction for 6 h.

[0046] After the esterification reaction is completed, the reaction system is cooled to 60 °C, and 20% magnesium carbonate suspension is slowly added dropwise until the pH value of the reaction system is between 7 and 8. Stirring is continued to carry out the neutralization reaction, and the reaction time is 2 h.

[0047] After the neutralization reaction, the reaction system was filtered to remove insoluble impurities, yielding a clear filtrate. 5 g of activated carbon was then added to the filtrate, and the temperature was gradually raised to 50 °C. The mixture was stirred and decolorized for 1 h, then filtered again to remove the activated carbon, yielding a purified filtrate. The purified filtrate was transferred to a rotary evaporator and concentrated under reduced pressure at 0.01 MPa and 70 °C until a crystalline film appeared. Finally, ethanol was added to the concentrate for alcohol precipitation and crystallization. After crystallization, the crystals were separated by centrifugation and placed in a vacuum drying oven at 60 °C for 6 h to obtain 294.6 g of magnesium glycerophosphate product, with a yield of 75.8%. Testing showed that the product purity was 99.7%, and the heavy metal content (as Pb) was less than 0.0003%.

[0048] As can be seen from the above embodiments, the above description of the present invention is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing high-purity magnesium glycerophosphate, characterized in that, Includes the following steps: (1) Esterification reaction: Glycerol and phosphoric acid are added to a reaction vessel in a certain molar ratio, a catalyst is added, and esterification reaction is carried out under specific temperature and reduced pressure conditions to produce crude glycerol phosphate ester; (2) Neutralization reaction: Slowly add magnesium source to the crude glycerophosphate obtained in step (1), control the reaction temperature and pH value, carry out neutralization reaction, and obtain magnesium glycerophosphate reaction solution; (3) Purification treatment: The glycerol magnesium phosphate reaction solution obtained in step (2) is filtered and decolorized with activated carbon; (4) Crystallization and drying: The filtrate purified in step (3) is concentrated under reduced pressure until a crystal film appears in the solution. Then, a low-carbon alcohol solvent is added for alcohol precipitation and crystallization. After crystallization, the crystals are separated by centrifugation and dried under vacuum to obtain the glycerol magnesium phosphate product.

2. The method according to claim 1, characterized in that, The molar ratio of glycerol and phosphoric acid in step (1) is 1:1.05~1.

2.

3. The method according to claim 1, characterized in that, The catalyst mentioned in step (1) is SO4. 2- / ZrO2、SO4 2- / TiO2、SO4 2- / Fe2O3、SO4 2- One or more of / TiO2-ZrO2 are selected, and the amount of catalyst added is 0.5~2.0% of the mass of glycerol.

4. The method according to claim 1, characterized in that, The esterification reaction in step (1) is carried out at a temperature of 80~120 ℃, under reduced pressure of 0.05~0.1 MPa, and for a reaction time of 2~8 h.

5. The method according to claim 1, characterized in that, The magnesium source mentioned in step (2) is one or more of magnesium oxide, magnesium hydroxide or magnesium carbonate, and the molar ratio of glycerol to magnesium source is 1:1.0~1.

6.

6. The method according to claim 1, characterized in that, The neutralization reaction temperature in step (2) is 50~80℃, the reaction time is 1~5 h, and the pH value is controlled at 6.0~9.0 during the reaction.

7. The method according to claim 1, characterized in that, The amount of activated carbon added in step (3) is 0.3~1.0% of the mass of the filtrate, the decolorization temperature is 40~60 ℃, and the decolorization time is 0.5~2.5 h.

8. The method according to claim 1, characterized in that, The low-carbon alcohol solvent mentioned in step (4) is one or more of n-butanol, isopropanol, methanol, and ethanol.

9. The method according to claim 1, characterized in that, The pressure of the vacuum concentration in step (4) is 0.01~0.05 MPa, and the concentration temperature is 60~80 ℃; the temperature of the vacuum drying is 50~70 ℃, and the drying time is 4~8 h.

10. The magnesium glycerol phosphate prepared according to the method of claims 1-8, characterized in that, The purity of the magnesium glycerophosphate is ≥99.5%, and the heavy metal content (as Pb) is ≤0.0005%.