A high purity 4,1',6'-trichloro-sucrose production process based on selective co-crystallization technology

Abstract

The application provides a high-purity 4,1',6'-trichloro-sucrose production process based on a selective co-crystallization technology, and the specific steps are as follows: adding an alkali solution to a sucrose ester chlorination reaction liquid containing 4,1',6'-trichloro-sucrose-6-acetate for alkaline hydrolysis; adding a mixed solution of a co-crystal ligand and a first solvent to the concentrated alkali-hydrolyzed solution after desolventizing, stirring and crystallizing to obtain white co-crystal powder containing 4,1',6'-trichloro-sucrose and the co-crystal ligand; dissolving the white co-crystal powder in a second solvent, adding a cation exchange resin to remove the co-crystal ligand, filtering, and recrystallizing the filtrate to obtain 4,1',6'-trichloro-sucrose powder with a purity greater than 99.8%. The co-crystallization technology can be used to efficiently and quickly separate high-purity 4,1',6'-trichloro-sucrose from a complex sugar mixture, and the complex recrystallization separation process of 4,1',6'-trichloro-sucrose-6-acetate in the existing industrial production is avoided.

Description

Technical Field

[0001] This invention relates to the field of crystallization separation in chemical separation technology, specifically to a highly selective co-crystallization separation method for 4,1',6'-sucralose. Background Technology

[0002] 4,1',6'-Sucralose is a sugar derivative formed by replacing the hydroxyl groups at the 4, 1', and 6' positions of sucrose with chlorine. It is a synthetic, non-nutritive sweetener with excellent properties such as high sweetness (600-800 times sweeter than sucrose), good flavor, long shelf life, no calories, and high safety. It is a commonly used additive in food and beverages. Currently, over 5,000 marketed products worldwide use 4,1',6'-Sucralose as a sweetener, enjoying widespread consumer popularity. Therefore, 4,1',6'-Sucralose, as a new generation of high-intensity sweeteners, has become a representative of the highest level and development direction of high-sweetness sweeteners due to its superior performance characteristics, showing promising commercial prospects.

[0003] The single-group protection method is currently the mainstream production process for 4,1',6'-sucralose. This method first acetylates the 6-hydroxyl group of sucrose to obtain sucrose-6-acetate, then selectively chlorinates sucrose-6-acetate to obtain 4,1',6'-sucralose-6-acetate, and finally hydrolyzes 4,1',6'-sucralose-6-acetate to obtain 4,1',6'-sucralose. Because the hydroxyl groups on sucrose have similar reactivity, each step—acetylation, chlorination, and hydrolysis—generates a large number of byproducts, making separation difficult. Existing 4,1',6'-sucralose production processes mainly employ conventional extraction or crystallization methods for product separation and purification. Due to the similar structure and properties of byproducts and main products at each step, single-step crystallization has limited separation effectiveness, often requiring multiple recrystallization steps to achieve product separation and purification. For example, the chlorination reaction solution obtained in the chlorination stage contains nearly 30 types of chlorinated sucrose esters (J Chromatogr. A, 2025, 1756, 466066), requiring a five-step crystallization / recrystallization process to separate 4,1',6'-sucralose-6-acetate. Using purified 4,1',6'-sucralose-6-acetate as an alkaline hydrolysis feedstock can effectively reduce the types and content of impurities in the alkaline hydrolysis products, lowering the difficulty of subsequent product separation and purification. However, even so, the alkaline hydrolysis reaction solution still requires more than two recrystallization steps to remove more than 10 types of dichlorosucrose, tetrachlorosucrose, and other impurities from the system to obtain the 4,1',6'-sucralose product. In summary, existing 4,1',6'-sucralose production technologies generally suffer from problems such as long process flow, complex and cumbersome separation process, and high energy and material consumption. There is an urgent need to invent a new and efficient separation method to simplify the production route, reduce production costs, and improve the quality of 4,1',6'-sucralose products.

[0004] Selective co-crystallization is a highly selective crystallization separation technique that enables the specific recognition, precise capture, and separation of target molecules based on minute differences in the microscopic interactions between different molecules. Our team has previously successfully applied selective co-crystallization to the separation and purification of two intermediates in the synthesis of the next-generation sweetener 4,1',6'-sucralose: sucrose-6-acetate and 4,1',6'-sucralose-6-acetate. Targeting the molecular structural characteristics of each intermediate, we designed binary co-crystallization of sucrose-6-acetate·acetate with acetic acid as the co-crystallization ligand, and ternary co-crystallization of 4,1',6'-sucralose-6-acetate·water·N,N-dimethylformamide with water and N,N-dimethylformamide as co-crystallization ligands. Based on these, we developed corresponding novel separation and purification methods (CN 114437146, CN116217635, CN 116284171, CN...). (117186163) Compared with traditional crystallization separation processes, selective co-crystallization technology can efficiently separate high-purity target products from sucrose esterification and chlorination reaction solutions containing dozens of isomer sugar derivatives in a single operation with only 1 to 2 crystallization operations, and has great potential for industrial application. Summary of the Invention

[0005] This invention addresses the problems existing in the production of 4,1',6'-sucralose by proposing a novel high-purity 4,1',6'-sucralose production process based on selective co-crystallization technology. Utilizing co-crystallization ligands with specific selectivity for 4,1',6'-sucralose, the target product 4,1',6'-sucralose is efficiently separated from complex chlorosucrose mixtures. This significantly simplifies the 4,1',6'-sucralose production process, overcomes the technical bottlenecks of low separation efficiency and high energy and material consumption in existing 4,1',6'-sucralose production technologies, reduces production costs, and yields 4,1',6'-sucralose products with a purity >99.8%. Specific steps include: (1) Take the chlorination reaction solution of sucrose ester, mix it with the alkaline solution at 0~20℃, adjust the pH value to 10~13, raise the temperature to 20~40℃ to carry out alkaline hydrolysis reaction, the reaction time is 0.5~4 h, add acidic components to adjust the pH value to 6.5~7.5, and after evaporation and desolventizing, the resulting reaction solution is obtained as an alkaline hydrolysis concentrate containing 4,1',6'-sucralose product; (2) Dissolve the alkaline hydrolysis concentrate in water to obtain a sugar-containing aqueous solution, wherein the mass ratio of 4,1',6'-sucralose to water is 1:1 to 1:50; dissolve the cocrystal ligand in the first solvent to obtain a cocrystal ligand solution, wherein the mass ratio of the cocrystal ligand to the first solvent is 1:1 to 1:50; mix with the sugar-containing aqueous solution at 10 to 40 °C, wherein the molar ratio of 4,1',6'-sucralose to the cocrystal ligand is 1:1 to 1:5. Stir and crystallize for 0.5 to 12 h, filter the precipitated white solid, wash away the residual mother liquor, and dry to obtain a white cocrystal powder; (3) Dissolve the white eutectic powder in the second solvent to obtain a eutectic solution, add cation exchange resin, the mass ratio of eutectic powder to cation exchange resin is 1:1~1:10, stir thoroughly and filter, the filtrate is recrystallized at 10~40℃, the precipitated crystals are filtered, the residual mother liquor is washed away and dried to obtain high-purity 4,1',6'-sucralose powder.

[0006] The sucrose ester chlorination reaction solution in step (1) of this invention is a reaction solution containing 4,1',6'-sucrose-6-acetate obtained by selectively acetylifying the 6-hydroxyl group of sucrose using a single-group protection method, followed by regioselective chlorination of the resulting acetylated reaction solution with thionyl chloride. The main components of the reaction solution include various chlorinated sucrose esters, reaction solvents (such as water, N,N-dimethylformamide, etc.), sugar tar, salt, coke, etc., wherein the content of 4,1',6'-sucrose-6-acetate in the chlorinated sucrose esters is about 10~96%, and the remainder is various chlorinated sucroses and chlorinated sucrose esters.

[0007] This invention directly uses sucrose ester chlorination reaction solution as the raw material for alkaline hydrolysis. After mixing with an alkaline solution, an alkaline hydrolysis reaction is carried out. Following alkaline hydrolysis, a concentrated alkaline hydrolysis solution is obtained after neutralization and desolvation. The alkaline solution acts as a catalyst in the alkaline hydrolysis process of 4,1',6'-sucralose-6-acetate, promoting the alkaline hydrolysis of 4,1',6'-sucralose-6-acetate to generate 4,1',6'-sucralose. The acidic substance is used to neutralize the alkali in the reaction system and adjust the pH of the system.

[0008] Preferably, the alkaline solution is ammonia water, or a solution formed by dissolving an alkali metal hydroxide or an alkali metal alkoxide in water or a low-carbon alcohol; the alkali metal hydroxide is any one or two of sodium hydroxide and potassium hydroxide; the alkali metal alkoxide is any one or more of sodium methoxide, potassium methoxide, sodium ethoxide, and potassium ethoxide; and the low-carbon alcohol is any one or two of methanol and ethanol.

[0009] Preferably, the acidic component is a cation exchange resin or a liquid acid; the liquid acid is a sulfuric acid solution or hydrochloric acid solution with a mass fraction of 5-50%.

[0010] Preferably, the mixing temperature of the sucrose ester chlorination reaction solution and the alkaline solution is 0~20℃.

[0011] Preferably, the pH value of the mixture of the sucrose ester chlorination reaction solution and the alkaline solution is 10-13.

[0012] Preferably, the alkaline hydrolysis reaction temperature is 20~40℃.

[0013] Preferably, the alkaline hydrolysis reaction time is 0.5 to 4 hours.

[0014] Preferably, after the alkaline hydrolysis reaction, an acid solution is added to neutralize the pH to 6.5-7.5.

[0015] After alkaline hydrolysis, chlorinated sucrose esters (including 4,1',6'-sucralose-6-acetate and other various chlorinated sucrose esters) in the chlorination reaction solution are converted into the target product 4,1',6'-sucralose and other various chlorinated sucrose byproducts. This invention uses organic molecules with strong hydrogen bond acceptors and a certain conjugation system as co-crystal ligands. Through their π-π stacking and hydrogen bonding, they alternately stack with 4,1',6'-sucralose molecular layers, causing the 4,1',6'-sucralose molecules to arrange themselves in an orderly manner and form co-crystals with the co-crystal ligands. The screened co-crystal ligands have excellent specificity for 4,1',6'-sucralose, accurately identifying 4,1',6'-sucralose from a mixture of chlorinated sucroses in the alkaline hydrolysis concentrate without forming co-crystals with other chlorinated sucroses.

[0016] Preferably, the co-crystallized ligand is 1,4-dihydroxyanthraquinone, 1,10-phenanthroline, 5-amino-1,10-phenanthroline, or 1,10-phenanthroline-5,6-dione.

[0017] In the eutectic process, the type and amount of the first solvent will affect the crystallization rate and the final yield, and the selected solvent should have good miscibility with water.

[0018] Preferably, the first solvent is one or more of water, methanol, ethanol, acetone, 2-butanone, 2-pentanone, acetonitrile, N,N-dimethylacetamide, N-methylpyrrolidone, n-butanol, tert-butanol, isopropanol, and N,N-dimethylformamide.

[0019] As a preference, the mass ratio of the eutectic ligand to the first solvent in the eutectic ligand solution is 1:1 to 1:50.

[0020] As a preference, in the sugar-containing aqueous solution of step (2), the mass ratio of 4,1',6'-sucralose to water is 1:1 to 1:50.

[0021] As a preference, the molar ratio of 4,1',6'-sucralose in the sugar-containing aqueous solution to the cocrystal ligand in the cocrystal ligand solution in step (2) is 1:1 to 1:5.

[0022] As a preferred method, the eutectic crystallization process in step (2) has a crystallization temperature of 10~40℃ and a crystallization time of 0.5~12h.

[0023] This invention separates the target product 4,1',6'-sucralose from the alkaline hydrolysis concentrate of a complex mixture using selective co-crystallization technology. The resulting white co-crystallized powder is a ternary co-crystallized mixture of 4,1',6'-sucralose, co-crystallized ligands, and water in a stoichiometric ratio of 1:1:1. The purity of 4,1',6'-sucralose can reach over 99% (calculated only as chlorinated sucrose and chlorinated sucrose esters), and the separation yield can reach over 90%.

[0024] To obtain high-purity 4,1',6'-sucralose, the cocrystal ligands in the cocrystal need to be removed. In this invention, the obtained white cocrystal powder is redissolved and mixed with a cation exchange resin. The acidic functional groups in the resin interact with the oxygen / nitrogen-containing cocrystal ligands in the solution, causing the ligands to adsorb onto the resin. After filtration, the ligands are separated from the remaining 4,1',6'-sucralose in the solution, achieving the removal of the cocrystal ligands. Subsequent conventional crystallization of the filtrate yields high-purity 4,1',6'-sucralose (purity can reach over 99.8%).

[0025] As a preference, the cation exchange resin in step (3) is a sulfonic acid type ion exchange resin, and the mass ratio of eutectic powder to cation exchange resin is 1:1 to 1:10.

[0026] Preferably, the second solvent in step (3) is one or more of methanol, acetonitrile, ethanol, isopropanol, acetone, 2-butanone, N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, n-butanol, tert-butanol, isopropanol, N,N-dimethylformamide, chloromethane, dichloromethane, trichloromethane, chloroethane, 1,1-dichloroethane, and 1,2-dichloroethane.

[0027] As a preference, in the eutectic solution of step (3), the mass ratio of white eutectic powder to the second solvent is 1:1 to 1:50.

[0028] As a preferred step, the recrystallization process in the second step is carried out at a crystallization temperature of 10~40℃ and a crystallization time of 0.5~12 h.

[0029] Compared with the prior art, the advantages and outstanding effects of the present invention are reflected in: (1) By utilizing selective co-crystallization technology, organic molecules with strong hydrogen bond acceptors and certain conjugated systems are used as co-crystallization ligands to achieve specific recognition, rapid targeting, and efficient separation of 4,1',6'-sucralose in complex sucralose mixtures, high-purity 4,1',6'-sucralose (>99%, based on sucralose and sucralose esters) can be separated in a single step. Compared with traditional crystallization separation technology, the technology of this invention has extremely high selectivity for 4,1',6'-sucralose, and the process is simple, the separation conditions are mild, the equipment requirements are low, and the single-pass separation yield is high (>90%, based on 4,1',6'-sucralose).

[0030] (2) The chlorination reaction solution of sucrose ester containing a large amount of chlorinated sucrose ester byproducts is used directly as the alkaline hydrolysis raw material, instead of the purified 4,1',6'-sucralose-6-acetate. This completely avoids the complicated and cumbersome separation and purification process of 4,1',6'-sucralose-6-acetate in the existing process (five-step crystallization / recrystallization process and corresponding supporting process), greatly shortens the process flow, simplifies the production route, and reduces production costs.

[0031] In summary, the novel process for producing high-purity 4,1',6'-sucralose based on selective co-crystallization proposed in this invention has advantages over existing 4,1',6'-sucralose synthesis processes, including a shorter process route, higher separation efficiency, and lower energy and material consumption. It can effectively reduce production costs while obtaining high-quality, high-purity 4,1',6'-sucralose products, and has promising prospects for industrial application.

[0032] It should be noted that the 4,1',6'-sucralose separation and purification technology based on selective co-crystallization and the above-mentioned co-crystallized ligands proposed in this invention is not limited to the separation and purification of 4,1',6'-sucralose in the alkaline hydrolysis concentrate described in this invention, but is also applicable to the separation and purification of other mixtures containing 4,1',6'-sucralose in existing 4,1',6'-sucralose production processes, such as the mother liquor separated from each step of the 4,1',6'-sucralose crystallization process. Attached Figure Description

[0033] Figure 1 This is a process flow diagram for the production of 4,1',6'-sucralose according to the present invention.

[0034] Figure 2 The images show the HPLC-ELSD chromatograms of the alkaline hydrolysis concentrate and the 4,1',6'-sucralose product obtained by separation using the present invention.

[0035] Figure 3FT-IR spectra of the ternary eutectic of 4,1',6'-sucralose·water·1,10-phenanthroline (a), 4,1',6'-sucralose (b), and the eutectic deligation product (c).

[0036] Figure 4 XRD patterns of the ternary eutectic of 4,1',6'-sucralose·water·1,10-phenanthroline (a), 4,1',6'-sucralose (b), and the eutectic deligation product (c).

[0037] Figure 5 ORTEP diagram of 4,1',6'-sucralose·water·1,10-phenanthroline ternary eutectic. Detailed Implementation

[0038] The present invention will be described in detail below with reference to specific embodiments.

[0039] Example 1: Preparation of sucrose ester chlorination reaction solution

[0040] 100 g of dibutyltin oxide was heated to 85 °C, and 26 g of acetic anhydride was added dropwise. The resulting mixture was stirred for 4 h. It was then mixed with cyclohexane and vacuum distilled to dryness to remove excess acetic anhydride, yielding the catalyst 1,3-bis(acetoxy)-1,1,3,3-tetrabutyldistannoxane (DSDA). 120 g of the prepared DSDA was completely dissolved in 720 mL of N,N'-dimethylformamide (DMF). The solution was continuously distilled off under reduced pressure at 85 °C until no liquid could be distilled off (approximately 2 h). The solution was then cooled to 0 °C, and 100 mL of DMF was added, followed by the dropwise addition of 30.5 g of acetic anhydride. The mixture was stirred for 3 h to ensure complete sucrose conversion. 500 mL of deionized water was then added to the mixture to terminate the reaction. Finally, the catalyst DSDA was extracted with cyclohexane to obtain the sucrose acetylation synthesis solution. The sucrose acetylation synthesis solution was distilled at 0.1 MPa and 60°C to remove more than 80% of the volatile organic solvents, yielding a concentrated sucrose ester solution (containing 68.64 wt% sucrose-6-acetic acid ester).

[0041] 100 g of sucrose ester concentrate was mixed with 120 g of DMF and added dropwise at 0 °C to a mixed solution of 120 mL of thionyl chloride and 450 mL of 1,1,2-trichloroethane. After the addition was complete, the mixture was allowed to react at room temperature for 0.5 h. Then, the mixture was heated to 85 °C at 1.5 °C / min and refluxed for 1 h. Next, the mixture was heated to 100 °C at 0.5 °C / min and refluxed for 1 h. Finally, the mixture was heated to 110 °C at 0.2 °C / min and refluxed for 1.5 h. The reaction was stopped and the mixture was cooled. After removing most of the solvent by vacuum distillation, 400 mL of methanol was added to dissolve the sucrose ester and the mixture was filtered. After removing the methanol by distillation, 1600 mL of water was added to dissolve the filtrate. The mixture was stirred thoroughly and allowed to stand overnight. The supernatant was then distilled to remove water, yielding a sucrose ester chlorination reaction solution (containing 68.05 wt% 4,1',6'-trichlorosucrose-6-acetate).

[0042] Example 2: Preparation of Alkaline Hydrolysis Concentrate I

[0043] Take 250 g of the sucrose ester chlorination reaction solution prepared in Example 1, add 25 wt% ammonia water dropwise at 10 °C and stir, adjust the pH value to 12, then raise the temperature to 40 °C and carry out alkaline hydrolysis reaction for 2 h, cool down to 20 °C, add 50 wt% sulfuric acid solution dropwise and adjust the pH value to 7.0, and after the resulting reaction solution is desolvated by rotary evaporation at 0.1 MPa and 50 °C, an alkaline hydrolysis concentrate (containing 74.11 wt% 4,1',6'-sucralose) is obtained.

[0044] Example 3: Preparation of Alkaline Hydrolysis Concentrate II

[0045] Take 250 g of the sucrose ester chlorination reaction solution prepared in Example 1, add 1 mol / L NaOH methanol solution dropwise at 5℃ and stir, adjust the pH value to 13, then raise the temperature to 40℃ and carry out alkaline hydrolysis reaction for 2 h, cool down to 20℃, add 50 g of NKC-9 cation exchange resin, stir thoroughly until the pH value of the reaction solution is 7.0, filter to remove the resin, and after the remaining reaction solution is desolvated by rotary evaporation at 0.1 MPa and 50℃, the alkaline hydrolysis concentrate (containing 55.16 wt% 4,1',6'-sucralose) is obtained.

[0046] Example 4: 20 g of the alkaline hydrolysis concentrate from Example 2 was dissolved in 260 g of water, and then a 1,10-phenanthroline solution (18 g of 1,10-phenanthroline dissolved in 26 g of methanol and 70 g of 2-pentanone) was added. The mixture was stirred and crystallized at 20 °C for 4 h. The precipitated solid was filtered, washed, and dried under vacuum at 50 °C to obtain a cocrystal of 4,1',6'-sucralose and 1,10-phenanthroline. The cocrystal was dissolved in 5 times its mass of methanol, and 50 g of NKC-9 ion exchange resin was added. The mixture was stirred for 1 h, and the resin was removed by filtration. The filtrate was recrystallized at room temperature, and the precipitated crystals were filtered, washed, and dried under vacuum at 50 °C to obtain 4,1',6'-sucralose with a purity of 99.95% and a yield of 91.19%.

[0047] Example 5: 20 g of the alkaline hydrolysis concentrate from Example 2 was dissolved in 176 g of water, and then a methanol solution of 5-amino-1,10-phenanthroline (15.96 g of 5-amino-1,10-phenanthroline dissolved in 17.6 g of methanol) was added. The mixture was stirred and crystallized at room temperature for 2 h. The precipitated solid was filtered, washed, and dried under vacuum at 50 °C to obtain a cocrystal of 4,1',6'-sucralose and 5-amino-1,10-phenanthroline. The cocrystal was dissolved in an equal mass of methanol, and 30 g of NKC-9 ion exchange resin was added. The mixture was stirred for 0.5 h, and the resin was removed by filtration. The filtrate was recrystallized at room temperature, and the precipitated crystals were filtered, washed, and dried under vacuum at 50 °C to obtain 4,1',6'-sucralose with a purity of 99.40% and a yield of 94.75%. Example 6:

[0048] 20 g of the alkaline hydrolysis concentrate from Example 3 was dissolved in 200 g of water, followed by the addition of a methanol solution of 1,4-dihydroxyanthraquinone (12.5 g of 1,4-dihydroxyanthraquinone dissolved in 24 g of methanol). The mixture was stirred and crystallized at room temperature for 2 h. The precipitated solid was filtered, washed, and dried under vacuum at 50 °C to obtain a cocrystal of 4,1',6'-sucralose and 1,4-dihydroxyanthraquinone. The cocrystal was dissolved in an equal mass of methanol, and 30 g of NKC-9 ion exchange resin was added. The mixture was stirred for 0.5 h, and the resin was removed by filtration. The filtrate was recrystallized at room temperature, and the precipitated crystals were filtered, washed, and dried under vacuum at 50 °C to obtain 4,1',6'-sucralose with a purity of 99.92% and a yield of 97.75%.

[0049] Table 1. Composition of Alkaline Hydrolysis Concentrate I, Alkaline Hydrolysis Concentrate II, and 4,1',6'-Sucralose Products in Each Example

[0050] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A process for producing high-purity 4,1',6'-sucralose based on selective co-crystallization technology, characterized in that, Includes the following steps: (1) Take the chlorination reaction solution of sucrose ester, mix it with the alkaline solution at 0~20℃, adjust the pH value to 10~13, raise the temperature to 20~40℃ to carry out alkaline hydrolysis reaction, the reaction time is 0.5~4 h, add acidic components to adjust the pH value to 6.5~7.5, and after evaporation and desolventizing, the resulting reaction solution is obtained as an alkaline hydrolysis concentrate containing 4,1',6'-sucralose product; (2) Dissolve the alkaline hydrolysis concentrate in water to obtain a sugar-containing aqueous solution, wherein the mass ratio of 4,1',6'-sucralose to water is 1:1 to 1:50; dissolve the cocrystal ligand in the first solvent to obtain a cocrystal ligand solution, wherein the mass ratio of the cocrystal ligand to the first solvent is 1:1 to 1:50; mix with the sugar-containing aqueous solution at 10 to 40°C, wherein the molar ratio of 4,1',6'-sucralose to the cocrystal ligand is 1:1 to 1:5; stir and crystallize for 0.5 to 12 h; filter the precipitated white solid, wash away the residual mother liquor, and dry to obtain a white cocrystal powder; (3) Dissolve the white eutectic powder in the second solvent to obtain a eutectic solution, add cation exchange resin, the mass ratio of eutectic powder to cation exchange resin is 1:1~1:10, stir thoroughly and filter, the filtrate is recrystallized at 10~40℃, filter the precipitated crystals, wash away the residual mother liquor, and dry to obtain high-purity 4,1',6'-sucralose powder. The sucrose ester chlorination reaction solution is obtained by selectively acetylifying sucrose at the 6-hydroxyl position using a single-group protection method, followed by regioselective chlorination of the resulting acetylated reaction solution with thionyl chloride to obtain a reaction solution containing 4,1',6'-trichlorosucrose-6-acetic acid ester.

2. The high-purity 4,1',6'-sucralose production process according to claim 1, characterized in that, The co-crystal ligands are organic molecules with strong hydrogen bond acceptors and certain conjugation systems, including 1,4-dihydroxyanthraquinone, 1,10-phenanthroline, 5-amino-1,10-phenanthroline, and 1,10-phenanthroline-5,6-dione.

3. The high-purity 4,1',6'-sucralose production process according to claim 1, characterized in that, The first solvent includes any one or more of water, methanol, ethanol, acetone, 2-butanone, 2-pentanone, acetonitrile, N,N-dimethylacetamide, N-methylpyrrolidone, n-butanol, tert-butanol, isopropanol, and N,N-dimethylformamide.

4. The high-purity 4,1',6'-sucralose production process according to claim 1, characterized in that, The second solvent is any one or more of methanol, acetonitrile, ethanol, isopropanol, acetone, 2-butanone, N,N-dimethylacetamide, N,N-dimethylformamide, N,N-dimethylformamide, N-methylpyrrolidone, n-butanol, tert-butanol, isopropanol, and chloroalkanes.

5. The high-purity 4,1',6'-sucralose production process according to claim 1, characterized in that, The cation exchange resin is a sulfonic acid type ion exchange resin.

6. The high-purity 4,1',6'-sucralose production process according to claim 1, characterized in that, In step (2), the stirring crystallization process has a crystallization temperature of 10~40℃ and a crystallization time of 0.5~12 h.

7. The high-purity 4,1',6'-sucralose production process according to claim 1, characterized in that, The recrystallization process in step (3) has a crystallization temperature of 10~40℃ and a crystallization time of 0.5~12 h.

8. The high-purity 4,1',6'-sucralose production process according to claim 1, characterized in that, The alkaline solution in step (1) is ammonia water, or a solution formed by dissolving an alkali metal hydroxide or an alkali metal alkoxide in water or a low-carbon alcohol; the alkali metal hydroxide is any one or two of sodium hydroxide and potassium hydroxide; the alkali metal alkoxide is any one or more of sodium methoxide, potassium methoxide, sodium ethoxide, and potassium ethoxide; the low-carbon alcohol is any one or two of methanol and ethanol.

9. The high-purity 4,1',6'-sucralose production process according to claim 1, characterized in that, The acidic component in step (1) is a cation exchange resin or a liquid acid; the liquid acid is a sulfuric acid solution or hydrochloric acid solution with a mass fraction of 10-50%.

10. High-purity 4,1',6'-sucralose prepared by the production process according to any one of claims 1-9.

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