A method for the synthesis of taurine

Abstract

The application discloses a synthesis method of taurine and belongs to the technical field of organic chemistry. The surface amine modification of silica is realized by the reaction between the surface hydroxyl group of silica and the siloxane containing an amine group, a new sulfonation catalyst is prepared, the weak alkaline environment provided by the exposed amino group better satisfies the sulfonation system of acrylamide and sodium bisulfite, a large number of hydroxyl groups on the surface of the silica particles are beneficial to the dispersion in water, the sulfonation efficiency is improved, and the silica particles are easy to separate from the sulfonation system.

Description

Technical Field

[0001] This invention belongs to the field of organic chemistry technology, specifically a method for synthesizing taurine. Background Technology

[0002] Taurine (chemical name 2-aminoethanesulfonic acid) is an essential non-protein amino acid for humans and animals. It exists in free form in almost all organs of humans and mammals, promoting the growth and development of the nervous system in humans and various mammals. It is widely used as a nutritional fortifier in food, health, and medicine, and can also be used as an intermediate in organic synthesis. In recent years, with the increasing popularity and expansion of taurine applications into multiple fields, its growth rate has been rapid and its prospects are promising, making it a fine chemical with a huge market.

[0003] Currently, my country's industry mainly uses the ethanolamine method and the ethylene oxide method to synthesize taurine. The ethanolamine method uses ethanolamine as a raw material to generate ethyleneimine under the action of a catalyst, which is then used to produce taurine under the action of a sulfonating agent. This route involves the highly toxic intermediate ethyleneimine, requires harsh reaction conditions, has a long production cycle, and generates large amounts of saline wastewater when separating taurine and byproduct inorganic salts, failing to meet the requirements of modern green chemistry. The ethylene oxide method uses ethylene oxide and sodium bisulfite as raw materials in an addition reaction to generate the intermediate sodium hydroxyethyl sulfonate, which then reacts with ammonia or ammonia water and is acidified to obtain taurine. The ethylene oxide method has a lower production cost than the ethanolamine method, but the ammonolysis process produces byproducts such as sodium iminodisulfonate and sodium thiamintriethanesulfonate, resulting in a low yield and complex impurities in the mother liquor, leading to poor separation efficiency.

[0004] Patent CN 114671784A reports a novel taurine synthesis route, which obtains taurine by sulfonation of acrylonitrile followed by biohydrolysis and Hoffmann rearrangement. This route offers milder reaction conditions and a safer process; however, the sulfonation step uses a sulfur dioxide / alkali system as the sulfonating agent, making pH control difficult. Furthermore, the release of carbon dioxide gas results in significant sulfur dioxide entrainment, leading to unstable sulfonation yields.

[0005] Francesco Fini (Adv Synth Catal, vol. 352, pp. 3163-3168) reported a mild method for the addition of electrophilic alkenes: using sodium bisulfite as the sulfonating agent and triethylamine as the catalyst, the reaction conditions were mild and good results were achieved. Although this method solves a series of problems associated with using sulfur dioxide as the sulfonating agent, the sodium bisulfite / triethylamine sulfonation system has low applicability to electrophilic alkenes, and the sulfonation yield is greatly affected by the group attached to the alkene. Summary of the Invention

[0006] To address the above problems, the purpose of this invention is to provide a method for synthesizing taurine.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] A method for synthesizing taurine, comprising the following steps:

[0009] (a) Sodium bisulfite is dissolved in water, silica surface-modified amine catalyst is added, heated to 50~80℃, and stirred thoroughly to prepare sulfonation reagent. Then, 20% acrylamide aqueous solution is added dropwise and reacted for 1~6h to obtain intermediate 3-amino-3-one propanesulfonate sodium reaction solution. The catalyst is removed by filtration of the obtained reaction solution to obtain filtrate.

[0010] The mass ratio of water to sodium bisulfite is 1:0.1~0.25;

[0011] The molar ratio of sodium bisulfite to acrylamide is 1.0~1.2:1;

[0012] The mass ratio of acrylamide to silica-modified amine catalyst is 1:0.01~0.1;

[0013] (b) Cool the filtrate obtained in step (a) to below 0°C, then add a mixture of sodium hypochlorite solution and liquid alkali dropwise. After the addition is complete, keep the temperature at 0~5°C for 0.5~1h, raise the temperature to 90~95°C and keep the temperature at 90~95°C for 0.5~1h. After the reaction is complete, lower the temperature to 25~30°C, add hydrochloric acid to adjust the pH of the system to 4.3±0.2, and obtain crude taurine by concentration, hot filtration and low temperature crystallization. Dissolve the obtained crude taurine in water to prepare a crude taurine aqueous solution with a mass concentration of 4~12%. Finally, remove sodium chloride by electrodialysis, concentrate and crystallize to obtain taurine.

[0014] The molar ratio of available chlorine in the sodium hypochlorite solution, the intermediate sodium 3-amino-3-one propanesulfonate in step a), and liquid alkali is 1.0~1.20:1:2.0~3.0.

[0015] Preferably, the mass ratio of water to sodium bisulfite in step (a) is 1:0.2; and the molar ratio of sodium bisulfite to acrylamide is 1:1.

[0016] Preferably, the mass ratio of acrylamide to silica surface-modified amine catalyst in step (a) is 1:0.05.

[0017] Preferably, in step (a), the reaction is heated to 65°C; after adding the 20% acrylamide aqueous solution, the reaction is carried out for 2 hours.

[0018] The silica-surface-modified amine catalyst was prepared according to the following method:

[0019] 1) Add chloroalkyltrialkoxysilane and triethylamine to the solvent and stir thoroughly. Then add cyclohexanediamine dropwise. After the addition is complete, continue stirring for 0.5 to 1 hour. Then cool to 0°C and let stand for 2 hours. Filter to obtain the filtrate.

[0020] 2) Add silica with a particle size of 5-10 μm and water to the filtrate obtained in step 1). Disperse the filtrate by ultrasonication at 300-500 W and 40-60 Hz for 20-30 min, then heat to 50-90 °C and react for 5-12 h. Filter and vacuum dry to obtain silica-modified amine catalyst with a total basicity of 0.5 mmol / g-2.5 mmol / g.

[0021] The solvent mentioned in step 1) is toluene, n-hexane, petroleum ether, or methyl tert-butyl ether.

[0022] The chloroalkyltrialkoxysilane mentioned in step 1) is 3-chloropropyltriethoxysilane or 3-chloropropyltrimethoxysilane.

[0023] The mass ratio of the chloroalkyltrialkoxysilane to the solvent in step 1) is 1:1.2~2.5.

[0024] The molar ratio of chloroalkyltrialkoxysilane, triethylamine and cyclohexanediamine in step 1) is 1:1~1.2:0.9~1.

[0025] The molar ratio of silicon dioxide in step 2) to chloroalkyltrialkoxysilane in step 1) is 0.5~1:1.

[0026] The mass ratio of water in step 2) to solvent in step 1) is 1:2~6.

[0027] Preferably, the mass ratio of the chloroalkyltrialkoxysilane to the solvent in step 1) is 1:1.5~1.8.

[0028] Preferably, the molar ratio of chloroalkyltrialkoxysilane, triethylamine and cyclohexanediamine in step 1) is 1:1.2:1.

[0029] Preferably, the chloroalkyltrialkoxysilane in step 1) is 3-chloropropyltriethoxysilane.

[0030] Preferably, the solvent in step 1) is toluene.

[0031] Preferably, the silica particles in step 2) have a diameter of 10 μm.

[0032] Preferably, in step 2), the temperature is raised to 70°C and the reaction is carried out for 8 hours.

[0033] Preferably, the molar ratio of silicon dioxide in step 2) to chloroalkyltrialkoxysilane in step 1) is 0.8:1.

[0034] Preferably, the mass ratio of water in step 2) to solvent in step 1) is 1:3.

[0035] The synthetic route for taurine in this invention is as follows:

[0036] .

[0037] Following Francesco Fini's report on acrylamide sulfonation, the experiment did not achieve the expected results. The experiment revealed that the sulfonation yield was low with a catalytic amount of triethylamine. Increasing the amount of triethylamine slightly improved the sulfonation yield, but the triethylamine was difficult to separate well in the aqueous system, resulting in a significant amount being introduced into the subsequent Hoffmann degradation reaction, ultimately leading to a low taurine yield. This application achieves amine modification of the silica surface through the reaction of hydroxyl groups on the silica surface with amine-containing siloxanes, preparing a novel sulfonation catalyst. The weakly alkaline environment provided by the exposed amino groups better meets the requirements of the acrylamide and sodium bisulfite sulfonation system. Furthermore, the large number of hydroxyl groups on the silica particle surface facilitates dispersion in water, improving sulfonation efficiency and making it easy to separate from the sulfonation system.

[0038] The present invention has the following advantages over the prior art:

[0039] The method for synthesizing taurine of the present invention involves synthesizing a silica-modified amine catalyst in the sulfonation reaction. The catalyst is easily dispersed in water, and the amino groups covering the surface provide suitable weak alkalinity for the sulfonation system, thereby improving the sulfonation efficiency. The catalyst is easy to separate, and the alkaline catalyst can be removed by simple filtration of the sulfonation reaction solution.

[0040] The method for synthesizing taurine in this invention solves the problem of the difficulty in separating triethylamine from the reaction system, effectively avoids side reactions caused by the introduction of alkali into the next reaction, and improves the yield of taurine. Attached Figure Description

[0041] Figure 1 This is a SEM characterization image of the silica surface-modified amine catalyst prepared in Example 1 of the present invention. Detailed Implementation

[0042] To better understand the technical solution of the present invention, the following detailed embodiments further illustrate the above-mentioned content of the present invention. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following examples. All technologies implemented based on the above-mentioned content of the present invention fall within the scope of the present invention.

[0043] Example 1: Preparation of silica-modified amine catalyst:

[0044] 3-Chloropropyltriethoxysilane (1 mol, 0.24 kg) and triethylamine (1.2 mol, 0.12 kg) were added to 0.3 kg of toluene and stirred thoroughly. Then, cyclohexanediamine (1 mol, 0.11 kg) was added dropwise. After the addition was complete, stirring was continued for 0.5 h. The mixture was allowed to stand at 0 °C for 2 h, filtered to remove the solid, and the filtrate was collected. Silica (0.8 mol, 0.048 kg) (particle size 5 μm) and 0.1 kg of water were added to the filtrate. The mixture was ultrasonically dispersed at an ultrasonic power of 400 W and an ultrasonic frequency of 50 Hz for 30 min. The mixture was then heated to 70 °C and reacted for 8 h. After filtration and vacuum drying, a silica-modified amine catalyst was obtained with a total basicity of 2.2 mmol / g. The total basicity was determined according to the method described in the literature: Liu Houquan. Determination of Basicity and Alkali Strength Distribution on the Surface of Solid Catalysts [J]. Petrochemical Industry, 1984, 13(10):645~648. SEM characterization images of silica-modified amine catalysts are shown below. Figure 1 As shown in the figure, the modified silica is a uniform spherical mass with a diameter of about 5 μm. A small portion has defects, and there is a small amount of rod-shaped silica formed by the hydrolysis of silane.

[0045] Synthesis of taurine:

[0046] Sodium bisulfite (1 mol, 0.1 kg) was dissolved in 1 kg of water, and 3.6 g of silica-modified amine catalyst was added. The mixture was heated to 65 °C and stirred thoroughly to prepare a sulfonating agent. A 20% acrylamide (1 mol, 0.355 kg) aqueous solution was added dropwise and reacted for 1 h to obtain a sodium 3-amino-3-one propanesulfonate solution. The catalyst was removed by filtration, yielding a filtrate. The filtrate was cooled to below 0 °C, and sodium hypochlorite solution (1 mol, 0.888 kg) (8.0% available chlorine) and liquid alkali (2 mol, ...) were added dropwise. A mixed solution of 0.25 kg (32%) was added dropwise and kept at 0℃ for 0.5 h. Then the temperature was raised to 95℃ and kept at that temperature for half an hour. After the reaction was completed, the temperature was lowered to 25℃ and hydrochloric acid was added to adjust the pH of the system to 4.3±0.2. After concentration, hot filtration and low-temperature crystallization, crude taurine was obtained. The crude taurine was dissolved in water to prepare a 10% crude taurine aqueous solution. Sodium chloride was removed by electrodialysis. The solution was concentrated and crystallized to obtain 123.6 g of taurine, with a yield of 98.8% based on acrylamide.

[0047] Example 2: Preparation of silica-modified amine catalyst:

[0048] 3-Chloropropyltrimethoxysilane (1 mol, 0.20 kg) and triethylamine (1.2 mol, 0.12 kg) were added to 0.24 kg of n-hexane and stirred thoroughly. Then, cyclohexanediamine (1 mol, 0.11 kg) was added dropwise. After the addition was complete, the mixture was stirred for 0.8 h and then allowed to stand at 0 °C for 2 h. The solid was removed by filtration, and the filtrate was collected. Silica (1 mol, 0.06 kg) (particle size 8 μm) and 0.12 kg of water were added to the filtrate. The mixture was ultrasonically dispersed at an ultrasonic power of 450 W and an ultrasonic frequency of 45 Hz for 30 min. The mixture was then heated to 50 °C and reacted for 5 h. After filtration and vacuum drying, a silica-modified amine catalyst with a total basicity of 1.9 mmol / g was obtained.

[0049] Synthesis of taurine:

[0050] Sodium bisulfite (1 mol, 0.1 kg) was dissolved in 0.5 kg of water, and 6.4 g of silica-modified amine catalyst was added. The mixture was heated to 80 °C and stirred thoroughly to prepare a sulfonating agent. A 20% acrylamide (1 mol, 0.355 kg) aqueous solution was added dropwise and reacted for 3 h to obtain a sodium 3-amino-3-one propanesulfonate solution. The catalyst was removed by filtration, yielding a filtrate. The filtrate was cooled to below 0 °C, and a sodium hypochlorite solution (1 mol, 0.888 kg) (8.0% available chlorine) was added dropwise. A mixed solution of alkali (2 mol, 0.25 kg) (32%) was added dropwise and the reaction was maintained at 3℃ for 0.6 h. Then the temperature was raised to 95℃ and maintained for 1 h. After the reaction was completed, the temperature was lowered to 28℃, and hydrochloric acid was added to adjust the pH of the system to 4.3±0.2. After concentration, hot filtration, and low-temperature crystallization, crude taurine was obtained. The obtained crude taurine was dissolved in water to prepare an 8% crude taurine aqueous solution. Sodium chloride was removed by electrodialysis, and the solution was concentrated and crystallized to obtain 122.6 g of taurine, with a yield of 98% based on acrylamide.

[0051] Example 3: Preparation of silica-modified amine catalyst:

[0052] 3-Chloropropyltriethoxysilane (1 mol, 0.24 kg) and triethylamine (1 mol, 0.1 kg) were added to 0.6 kg of toluene and stirred thoroughly. Then, cyclohexanediamine (0.9 mol, 0.1 kg) was added dropwise. After the addition was complete, the mixture was stirred for 1 h and allowed to stand at 0 °C for 2 h. The solid was removed by filtration, and the filtrate was collected. 0.5 mol, 0.03 kg of silica (particle size 10 μm) and 0.1 kg of water were added to the filtrate. The mixture was ultrasonically dispersed at an ultrasonic power of 500 W and an ultrasonic frequency of 40 Hz for 30 min. The mixture was then heated to 90 °C and reacted for 5 h. After filtration and vacuum drying, a silica-modified amine catalyst with a total basicity of 2.4 mmol / g was obtained.

[0053] Synthesis of taurine:

[0054] Sodium bisulfite (1 mol, 0.1 kg) was dissolved in 0.4 kg of water, and 1 g of silica-modified amine catalyst was added. The mixture was heated to 70 °C and stirred thoroughly to prepare a sulfonating agent. A 20% acrylamide (1 mol, 0.355 kg) aqueous solution was added dropwise and reacted for 4 h to obtain a sodium 3-amino-3-one propanesulfonate solution. The catalyst was removed by filtration, and the filtrate was obtained. The temperature of the filtrate was lowered to below 0 °C, and sodium hypochlorite solution (1 mol, 0.888 kg) (8.0% available chlorine) and liquid alkali ( ) were added dropwise. A mixed solution of 2 mol (0.25 kg) (32%) was added dropwise and then kept at 5℃ for 0.5 h. The temperature was then raised to 93℃ and kept at that temperature for 0.8 h. After the reaction was completed, the temperature was lowered to 30℃ and the pH was adjusted to 4.3±0.2 with hydrochloric acid. After concentration, hot filtration and low-temperature crystallization, crude taurine was obtained. The crude taurine was dissolved in water to prepare a 4% (w / w) crude taurine aqueous solution. Sodium chloride was removed by electrodialysis. The solution was concentrated and crystallized to obtain 121.5 g of taurine, with a yield of 97.1% based on acrylamide.

[0055] Example 4: Preparation of silica-modified amine catalyst:

[0056] 3-Chloropropyltriethoxysilane (1 mol, 0.24 kg) and triethylamine (1.2 mol, 0.12 kg) were added to 0.45 kg of methyl tert-butyl ether and stirred thoroughly. Then, cyclohexanediamine (0.9 mol, 0.1 kg) was added dropwise. After the addition was complete, the mixture was stirred for 1 h and allowed to stand at 0 °C for 2 h. The solid was removed by filtration, and the filtrate was collected. 0.8 mol, 0.048 kg of silica (particle size 10 μm) and 0.15 kg of water were added to the filtrate. The mixture was ultrasonically dispersed at an ultrasonic power of 300 W and an ultrasonic frequency of 60 Hz for 30 min. The mixture was then heated to 90 °C and reacted for 12 h. After filtration and vacuum drying, a silica-modified amine catalyst with a total basicity of 1.8 mmol / g was obtained.

[0057] Synthesis of taurine:

[0058] Sodium bisulfite (1 mol, 0.1 kg) was dissolved in 0.5 kg of water, and 5.4 g of silica-modified amine catalyst was added. The mixture was heated to 60 °C and stirred thoroughly to prepare a sulfonating agent. A 20% acrylamide (1 mol, 0.355 kg) aqueous solution was added dropwise and reacted for 5 h to obtain a sodium 3-amino-3-one propanesulfonate solution. The catalyst was removed by filtration, and the filtrate was obtained. The temperature of the filtrate was lowered to below 0 °C, and sodium hypochlorite solution (1 mol, 0.888 kg) (8.0% available chlorine) and liquid alkali (2 mol, ...) were added dropwise. A mixed solution of 0.25 kg (32%) was added dropwise and kept at 0℃ for 0.5 h. The temperature was then raised to 95℃ and kept at that temperature for half an hour. After the reaction was completed, the temperature was lowered to 25℃, and hydrochloric acid was added to adjust the pH to 4.3±0.2. After concentration, hot filtration, and low-temperature crystallization, crude taurine was obtained. The crude taurine was dissolved in water to prepare a 12% crude taurine aqueous solution. Sodium chloride was removed by electrodialysis, and the solution was concentrated and crystallized to obtain 121.38 g of taurine, with a yield of 97% based on acrylamide.

[0059] Example 5: Preparation of silica-modified amine catalyst:

[0060] 3-Chloropropyltrimethoxysilane (1 mol, 0.2 kg) and triethylamine (1.2 mol, 0.12 kg) were added to 0.3 kg of petroleum ether and stirred thoroughly. Then, cyclohexanediamine (1 mol, 0.11 kg) was added dropwise. After the addition was complete, the mixture was stirred for 0.7 h and then allowed to stand at 0 °C for 2 h. The solid was removed by filtration, and the filtrate was collected. 0.9 mol, 0.054 kg of silica (particle size 10 μm) and 0.1 kg of water were added to the filtrate. The mixture was ultrasonically dispersed at an ultrasonic power of 400 W and an ultrasonic frequency of 50 Hz for 25 min. The mixture was then heated to 80 °C and reacted for 8 h. After filtration and vacuum drying, a silica-modified amine catalyst with a total basicity of 1.3 mmol / g was obtained.

[0061] Synthesis of taurine:

[0062] Sodium bisulfite (1 mol, 0.1 kg) was dissolved in 0.5 kg of water, and 2 g of silica-modified amine catalyst was added. The mixture was heated to 60 °C and stirred thoroughly to prepare a sulfonating agent. A 20% acrylamide (1 mol, 0.355 kg) aqueous solution was added dropwise and reacted for 2 h to obtain a sodium 3-amino-3-one propanesulfonate solution. The catalyst was removed by filtration, and the filtrate was obtained. The temperature of the filtrate was lowered to below 0 °C, and sodium hypochlorite solution (1 mol, 0.888 kg) (8.0% available chlorine) and liquid alkali (2... A mixed solution of 0.25 kg (32%) was added dropwise and then kept at 5°C for 0.5 h. The temperature was then raised to 95°C and kept at that temperature for 0.9 h. After the reaction was completed, the temperature was lowered to 28°C and the pH was adjusted to 4.3 ± 0.2 with hydrochloric acid. After concentration, hot filtration and low-temperature crystallization were performed to obtain crude taurine. The crude taurine was dissolved in water to prepare a 10% crude taurine aqueous solution. Sodium chloride was removed by electrodialysis. The solution was concentrated and crystallized to obtain 122.0 g of taurine, with a yield of 97.5% based on acrylamide.

[0063] Comparative Example 1: Preparation of taurine using triethylamine as a base catalyst:

[0064] Sodium bisulfite (1 mol, 0.1 kg) was dissolved in 0.5 kg of water, and triethylamine (0.2 mol, 0.02 kg) was added. The mixture was heated to 65 °C and stirred thoroughly to prepare a sulfonating agent. A 20% acrylamide aqueous solution (1 mol, 0.355 kg) was then added dropwise and reacted for 2 hours to obtain a sodium 3-amino-3-one propanesulfonate solution. The reaction solution was heated to 95 °C to remove some of the triethylamine. The filtrate temperature was lowered to below 0℃, and a mixed solution of sodium hypochlorite solution (1 mol, 0.888 kg) (8.0% available chlorine) and liquid alkali (2 mol, 0.25 kg) (32%) was added dropwise. After the addition was complete, the mixture was kept at 0℃ for 0.5 h, then the temperature was raised to 95℃ and kept at that temperature for half an hour. After the reaction was completed, the temperature was lowered to 25℃, and hydrochloric acid was added to adjust the pH to 4.3±0.2. After concentration, hot filtration, and low-temperature crystallization, crude taurine was obtained. The crude taurine was dissolved in water and subjected to electrodialysis to remove sodium chloride. The solution was concentrated and crystallized to obtain 95 g of taurine, with a yield of 76% based on acrylamide. It can be seen that the yield of taurine prepared using triethylamine as a base catalyst is lower than that prepared using silica-modified amine catalyst.

[0065] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Based on the technical solutions of the present invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the present invention.

Claims

1. A method for synthesizing taurine, characterized in that: Includes the following steps: (a) Sodium bisulfite is dissolved in water, silica surface-modified amine catalyst is added, heated to 50~80℃, and stirred thoroughly to prepare sulfonation reagent. Then, 20% acrylamide aqueous solution is added dropwise and reacted for 1~6h to obtain intermediate 3-amino-3-one propanesulfonate sodium reaction solution. The catalyst is removed by filtration of the obtained reaction solution to obtain filtrate. The mass ratio of acrylamide to silica-modified amine catalyst is 1:0.01~0.1; The silica-surface-modified amine catalyst was prepared according to the following method: 1) Add chloroalkyltrialkoxysilane and triethylamine to the solvent and stir thoroughly. Then add cyclohexanediamine dropwise. After the addition is complete, continue stirring for 0.5 to 1 hour. Then cool to 0°C and let stand for 2 hours. Filter to obtain the filtrate. 2) Add silica with a particle size of 5-10 μm and water to the filtrate obtained in step 1), and ultrasonically disperse it for 20-30 min at 300-500 W and 40-60 Hz. Then heat it to 50-90 °C and react for 5-12 h. Filter and vacuum dry to obtain silica-modified amine catalyst with a total basicity of 0.5 mmol / g-2.5 mmol / g. The solvent mentioned in step 1) is toluene, n-hexane, petroleum ether, or methyl tert-butyl ether; the chloroalkyltrialkoxysilane is 3-chloropropyltriethoxysilane or 3-chloropropyltrimethoxysilane; In step 1), the mass ratio of the chloroalkyltrialkoxysilane to the solvent is 1:1.2~2.5; the molar ratio of the chloroalkyltrialkoxysilane, triethylamine, and cyclohexanediamine is 1:1~1.2:0.9~1; in step 2), the molar ratio of the silicon dioxide to the chloroalkyltrialkoxysilane in step 1) is 0.5~1:1; and in step 2), the mass ratio of the water to the solvent in step 1) is 1:2~6. (b) Cool the filtrate obtained in step (a) to below 0°C, then add a mixture of sodium hypochlorite solution and liquid alkali dropwise. After the addition is complete, keep the temperature at 0~5°C for 0.5~1h, raise the temperature to 90~95°C and keep the temperature at 90~95°C for 0.5~1h. After the reaction is complete, lower the temperature to 25~30°C, add hydrochloric acid to adjust the pH of the system to 4.3±0.2, and obtain crude taurine by concentration, hot filtration and low temperature crystallization. Dissolve the obtained crude taurine in water to prepare a crude taurine aqueous solution with a mass concentration of 4~12%. Finally, remove sodium chloride by electrodialysis, concentrate and crystallize to obtain taurine. The sodium hypochlorite solution contains available chlorine, and the intermediate 3-amino-3-one propanesulfonic acid mentioned in step a) The molar ratio of sodium to liquid alkali is 1.0~1.20:1:2.0~3.

0.

2. The method for synthesizing taurine as described in claim 1, characterized in that: Step (a) The mass ratio of water to sodium bisulfite is 1:0.1~0.25; the molar ratio of sodium bisulfite to acrylamide is 1.0~1.2:

1.

3. The method for synthesizing taurine as described in claim 1, characterized in that: In step (a), the mass ratio of water to sodium bisulfite is 1:0.2; the molar ratio of sodium bisulfite to acrylamide is 1:1; and the mass ratio of acrylamide to silica surface-modified amine catalyst is 1:0.

05.

4. The method for synthesizing taurine as described in claim 1, characterized in that: In step (a), the reaction is heated to 65°C; after adding the 20% acrylamide aqueous solution, the reaction is carried out for 2 hours.

5. The method for synthesizing taurine as described in claim 1, characterized in that: In step 1), the mass ratio of chloroalkyltrialkoxysilane to solvent is 1:1.5~1.8; the molar ratio of chloroalkyltrialkoxysilane, triethylamine and cyclohexanediamine is 1:1.2:1; in step 2), the molar ratio of silicon dioxide to chloroalkyltrialkoxysilane in step 1) is 0.8:1; and the mass ratio of water to solvent in step 1) is 1:

3.

6. The method for synthesizing taurine as described in claim 1, characterized in that: The chloroalkyltrialkoxysilane mentioned in step 1) is 3-chloropropyltriethoxysilane; the solvent is toluene.

7. The method for synthesizing taurine as described in claim 1, characterized in that: The silica particles in step 2) are 10 μm in size; the reaction in step 2) is heated to 70 °C for 8 h.

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