WO2024082175A1 - 一种三氯蔗糖精品的制备方法 - Google Patents

一种三氯蔗糖精品的制备方法 Download PDF

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WO2024082175A1
WO2024082175A1 PCT/CN2022/126183 CN2022126183W WO2024082175A1 WO 2024082175 A1 WO2024082175 A1 WO 2024082175A1 CN 2022126183 W CN2022126183 W CN 2022126183W WO 2024082175 A1 WO2024082175 A1 WO 2024082175A1
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sucralose
ethyl ester
target product
phase
crystallization
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PCT/CN2022/126183
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English (en)
French (fr)
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陈永乐
沈东东
陈宇涵
肖士东
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安徽金禾实业股份有限公司
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Priority to PCT/CN2022/126183 priority Critical patent/WO2024082175A1/zh
Priority to CN202280004566.4A priority patent/CN116075519A/zh
Publication of WO2024082175A1 publication Critical patent/WO2024082175A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
    • C07H1/00—Processes for the preparation of sugar derivatives
    • C07H1/06—Separation; Purification
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
    • C07H5/00—Compounds containing saccharide radicals in which the hetero bonds to oxygen have been replaced by the same number of hetero bonds to halogen, nitrogen, sulfur, selenium, or tellurium
    • C07H5/02—Compounds containing saccharide radicals in which the hetero bonds to oxygen have been replaced by the same number of hetero bonds to halogen, nitrogen, sulfur, selenium, or tellurium to halogen

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  • the present invention relates to the technical field of fine chemicals, and in particular to a method for preparing fine sucralose.
  • Sucralose commonly known as sucralose, appears as white crystalline powder or granules. It is a new generation of sweetener made from sucrose. Its sweetness is 600 times that of sucrose, with a pure taste and does not participate in human metabolism. It is a "zero-calorie" sugar that can be used by diabetics, patients with cardiovascular and cerebrovascular diseases, and the elderly. It also has the characteristics of good stability and high safety, and is widely used in food, beverages, daily chemicals, medicine and other fields.
  • sucrose-6-acetate mainly uses sucrose as raw material to obtain sucrose-6-acetate through esterification, sucrose-6-acetate is chlorinated to obtain sucralose-6-acetate, and sucralose-6-acetate is purified after alcoholysis to obtain sucralose fine products.
  • the synthesis of sucrose-6-acetate mainly includes trimethyl orthoacetate process (for example, Chinese patents CN106749440A, CN105254684A) and organotin process (for example, Chinese patents CN102639550A, CN1528772A).
  • sucralose-6-acetate mainly includes phosgene/solid phosgene process (CN103328495A, CN1660868A) and thionyl chloride process (for example, Chinese patents CN101270136A, CN102417526A).
  • sucralose from sucralose-6-acetate there are many methods for preparing sucralose from sucralose-6-acetate, such as the sodium methoxide method (e.g., Chinese patents CN101918421A and CN1176094A), the organic amine method (e.g., Chinese patents CN101260127A, CN112771060A, CN101260127A), the alkaline ion exchange resin method (e.g., Chinese patents CN112409419A and CN102336787A), the alkali metal oxide method (e.g., Chinese patents CN113004345A, CN104004032A, and CN112805291A), and the alkali metal hydroxide method (e.g., Chinese patents CN1814609A, CN101012250A, and CN102321122A).
  • the sodium methoxide method e.g., Chinese patents CN101918421A and CN1176094A
  • the traditional production method of fine sucralose is mainly as follows: using pure sucralose-6-acetate (purity above 99%) as raw material, preparing crude sucralose by alcoholysis (sodium methoxide/methanol) or alkaline hydrolysis (liquid alkali/water), and then purifying (butyl acetate extraction and impurity removal, and then crystallization in water) to obtain fine sucralose.
  • the crystallization mother liquor is recycled and needs to be concentrated during the recycling process.
  • the above purification steps will cause sucralose to oxidize and form new impurities.
  • the new impurities are enriched during the recycling process of the crystallization mother liquor, which in turn affects the crystallization of sucralose.
  • the crystallization mother liquor (approximately 5 times) can no longer be recycled and can only be treated as wastewater.
  • an object of the present invention is to provide a method for preparing a fine sucralose product.
  • the crystallization mother liquor can be recycled for multiple times and the yield and purity of the fine sucralose product are high.
  • the present invention provides a method for preparing fine sucralose, comprising the following steps:
  • the present invention provides a method for preparing fine sucralose, comprising the following steps:
  • beating and decolorizing the crude sucralose is mixed with ethyl acetate, and solid-liquid separation is performed after beating to obtain a beating mother liquor and a beating target product, respectively; the beating target product is dissolved in water, and the obtained beating target product aqueous solution is decolorized by activated carbon to obtain a beating and decolorized target product liquid;
  • Second crystallization dissolving the first crystallization target product in water, and subjecting the obtained first crystallization target product aqueous solution to second crystallization to obtain a second crystallization target product and a secondary crystallization mother liquor, respectively; the secondary crystallization mother liquor is recycled to step (1) to dissolve the pulping target product;
  • the third crystallization dissolving the second crystalline target product in water, decolorizing the obtained second crystalline target product aqueous solution with activated carbon, and then performing solid-liquid separation to obtain a second crystalline decolorized target product aqueous solution and recovered activated carbon; concentrating the second crystalline decolorized target product aqueous solution, and performing the third crystallization on the obtained second crystalline decolorized target product concentrated solution to obtain a third crystalline target product and a tertiary crystallization mother liquor; drying the third crystalline target product to obtain sucralose concentrate; the tertiary crystallization mother liquor is reused in step (3) to dissolve the first crystalline target product, and the recovered activated carbon is reused in step (1) to perform activated carbon decolorization on the pulping target product aqueous solution.
  • the crude sucralose comprises the following components in percentage by weight: 85-95% sucralose, 0.5-1% sucralose-6-acetate, 1-3% ethyl acetate, and 1-13.5% caramel impurities.
  • the ratio of the mass of the crude sucralose to the volume of ethyl acetate for pulping is 1 kg: 1-1.5 L.
  • the dissolving temperature is 30 to 50°C;
  • the sugar content of the pulping target product aqueous solution is 20-40%.
  • the sugar content of the pulping and decolorizing target product concentrate is 40-65%.
  • the temperature of the first crystallization is room temperature and the time is 8 to 16 hours.
  • the dissolving temperature is 40 to 60°C;
  • the sugar content of the aqueous solution of the first crystallized target product is 40-65%.
  • the temperature of the second crystallization is room temperature and the time is 8 to 16 hours.
  • the dissolving temperature is 40 to 60°C;
  • the sugar content of the aqueous solution of the second crystallized decolorized target product is 20-30%.
  • the sugar content of the second crystallized decolorized target product concentrate is 40-65%.
  • the temperature of the third crystallization is 30 to 50° C., and the time is 4 to 12 hours.
  • the method for preparing crude sucralose comprises the following steps:
  • the raw material liquid is an aqueous solution comprising sucralose-6-acetate, sucralose diester and tetrachlorosucrose-6-acetate;
  • step (e) washing the second ethyl ester phase with water to obtain a fourth aqueous phase and a third ethyl ester phase, respectively; the fourth aqueous phase is reused in step (b) to dissolve the first ethyl ester phase concentrate;
  • step (h) washing the fifth ethyl ester phase with water to obtain a fifth aqueous phase and a sixth ethyl ester phase respectively; the fifth aqueous phase is returned to step (b) to dissolve the first ethyl ester phase concentrate.
  • the pulping mother liquor and the primary crystallization mother liquor are recycled to prepare crude sucralose.
  • the pulping mother liquor is used to dissolve the first ethyl ester phase concentrate, and the primary crystallization mother liquor is mixed with the third ethyl ester phase and then azeotropically dehydrated.
  • the content of sucralose in the third aqueous phase, the fourth aqueous phase and the fifth aqueous phase is independently ⁇ 0.5 g/L.
  • the temperature of the ethyl acetate extraction is 40-60° C., and the number of extractions is 5-8 times; and the volume ratio of the raw material liquid to the ethyl acetate used for a single ethyl acetate extraction is 1:0.2-0.5.
  • the content of ethyl acetate in the aqueous solution of sucralose-6-acetate is less than 0.5 g/L.
  • the pH value of the alkaline hydrolysis reaction is 11-13, the temperature is 0-10° C., and the time is 3-6 hours.
  • the neutralization and filtration temperatures are independently 50-70°C.
  • the number of ethyl acetate extractions is 4 to 7 times; the volume ratio of the second aqueous phase to the ethyl acetate used in a single ethyl acetate extraction is 1:1 to 3;
  • the ethyl ester phases obtained from the first and second ethyl ester extractions are combined as the second ethyl ester phase;
  • the ethyl ester phase obtained from the 3rd to 7th ethyl acetate extractions is used for the ethyl acetate extraction of the second aqueous phase in the preparation process of the next batch of crude sucralose.
  • the number of water washings is 3 to 6 times; the volume ratio of the second ethyl ester phase to the water used for the single water washing is 1:0.1 to 0.3;
  • the aqueous phase obtained from the first water washing is used as the fourth aqueous phase;
  • the aqueous phase obtained from the 2nd to 6th water washing is used for washing the second ethyl ester phase in the preparation process of the next batch of crude sucralose.
  • the water content of the third ethyl ester phase concentrate is less than 0.5 wt %.
  • the sugar content of the fourth ethyl ester phase is 40-60%.
  • the crystallization temperature is 40 to 60° C. and the time is 12 to 30 hours.
  • the prior art cannot achieve the material balance problem between the target product and impurities in the process of using crude sucralose as raw material to produce fine sucralose, which will eventually lead to the mother liquor being discarded due to excessive impurities after being recycled several times.
  • the preparation method provided by the present invention can effectively remove the impurities in the crude sucralose and the impurities generated by oxidation during the application of the crystallization mother liquor by ethyl acetate pulping treatment of the crude sucralose, two different stages of activated carbon decolorization and impurity removal, and three crystallizations, thereby ensuring the stability of the subsequent crystallization mother liquor, solving the problem of impurity enrichment in the crystallization mother liquor during the recycling process, thereby achieving the crystallization mother liquor generated in the refining process can be repeatedly recycled, reducing the loss of sucralose in the purification process, and significantly improving the yield of sucralose.
  • the present invention can make full use of the residual sucralose in the secondary crystallization mother liquor and the tertiary crystallization mother liquor by recycling the secondary crystallization mother liquor to dissolve the pulping target product and the tertiary crystallization mother liquor to dissolve the first crystallization target product, reducing the large amount of loss caused by sucralose in the crystallization process, and significantly improving the yield of sucralose.
  • the pulping mother liquor contains a large amount of fat-soluble impurities and part of sucralose
  • the primary crystallization mother liquor contains residual sucralose.
  • the present invention uses the pulping mother liquor and the primary crystallization mother liquor to prepare the crude sucralose product, thereby avoiding the loss of sucralose and improving the overall yield of sucralose.
  • the preparation method provided by the present invention can effectively realize the effective combination of the preparation of crude sucralose and the purification of crude sucralose, achieve the balance between sucralose and impurities in the purification process, and realize the long-term multiple recycling of the mother liquor.
  • the present invention performs alkaline hydrolysis in an alkali metal hydroxide-water system, and sucralose-6-acetate, sucralose diester and sucralose-6-acetate are all alkaline-hydrolyzed in the presence of a strong alkaline aqueous solution to generate corresponding sucralose and sucralose.
  • Sucralose can continue to be dechlorinated in the presence of a strong alkaline aqueous solution to form sucralose, so that the sucralose-6-acetate and impurities (sucralose diester and sucralose-6-acetate) in the raw material liquid are converted into sucralose, thereby significantly improving the raw material conversion rate and the yield of sucralose.
  • the raw material conversion rate and the yield of sucralose in the method provided by the present invention are significantly improved.
  • the present invention adopts a dual system of ethyl acetate and water, and can realize mutual application between the dual systems to extract and remove impurities, enrich sucralose, so that sucralose can be crystallized in ethyl acetate in large quantities, and recover sucralose by repeated application, thereby avoiding the loss of sucralose and greatly improving the overall yield of sucralose.
  • the preparation method provided by the present invention has low production cost, safety and environmental protection.
  • FIG1 is a flow chart of the preparation process of sucralose fine product
  • FIG. 2 is a process flow chart of preparing crude sucralose using a hydrolysis system and the crude sucralose.
  • the present invention provides a method for preparing fine sucralose, comprising the following steps:
  • the present invention mixes crude sucralose with ethyl acetate, performs solid-liquid separation after pulping, and obtains pulping mother liquor and pulping target product respectively; the pulping target product is dissolved in water, and the obtained pulping target product aqueous solution is mixed with activated carbon for decolorization to obtain pulping decolorized target product liquid; the pulping mother liquor is used to prepare crude sucralose.
  • the crude sucralose includes the following components in percentage by mass: sucralose is preferably 85-95%, more preferably 88-92%; sucralose-6-acetate is preferably 0.5-1%, more preferably 0.6-0.9%; ethyl acetate is preferably 1-3%, more preferably 1.5-2.5%; caramel impurities are preferably 1-13.5%, more preferably 5-10%.
  • the ratio of the mass of the crude sucralose to the volume of ethyl acetate for pulping is preferably 1kg:1-1.5L, more preferably 1kg:1.1-1.4L, and further preferably 1kg:1.3-1.4L.
  • the beating temperature is preferably 20 to 40°C, more preferably room temperature.
  • the beating time is preferably 5 to 15 minutes, more preferably 10 minutes; the beating is preferably carried out under stirring.
  • the present invention does not specifically limit the solid-liquid separation method, and may adopt a solid-liquid separation method well known to those skilled in the art, such as filtration, suction filtration or filter press.
  • the dissolution temperature is preferably 30 to 50°C, more preferably 30 to 45°C, and further preferably 30 to 40°C; the sugar content (Bx) of the aqueous solution of the target product of beating is preferably 20 to 40%, more preferably 25 to 35%, and further preferably 30%.
  • the activated carbon is preferably plant activated carbon, more preferably including at least one of coconut shell activated carbon and fruit shell activated carbon.
  • Coal-based activated carbon will have residual sulfur impurities, which will affect the taste of sucralose products.
  • the plant activated carbon used in the present invention has a low sulfur content and will not affect the product quality of sucralose.
  • the mass of the activated carbon is preferably 0.5-1% of the dry weight of the crude sucralose, and more preferably 0.6-0.9%.
  • the decolorization temperature is preferably 40-50°C, more preferably 45°C
  • the decolorization time is preferably 5-10min, more preferably 6-8min
  • the purpose of the activated carbon decolorization is to remove colored impurities in the crude sucralose.
  • the present invention preferably further includes solid-liquid separation of the obtained decolorization system to obtain pulping decolorization target product liquid and activated carbon residue respectively.
  • the present invention does not specifically limit the solid-liquid separation method, and a solid-liquid separation method well known to those skilled in the art can be used, such as filtration, suction filtration or filter pressing.
  • the activated carbon residue is preferably treated as solid waste.
  • the method for preparing crude sucralose preferably comprises the following steps:
  • the raw material liquid is an aqueous solution comprising sucralose-6-acetate, sucralose diester and tetrachlorosucrose-6-acetate;
  • step (e) washing the second ethyl ester phase with water to obtain a fourth aqueous phase and a third ethyl ester phase, respectively; the fourth aqueous phase is reused in step (b) to dissolve the first ethyl ester phase concentrate;
  • step (h) washing the fifth ethyl ester phase with water to obtain a fifth aqueous phase and a sixth ethyl ester phase respectively; the fifth aqueous phase is returned to step (b) to dissolve the first ethyl ester phase concentrate.
  • the present invention extracts the raw material liquid with ethyl acetate to obtain a first ethyl ester phase and a first aqueous phase respectively; the first ethyl ester phase is concentrated to obtain a first ethyl ester phase concentrate; the raw material liquid is an aqueous solution including sucralose-6-acetate, sucralose diester and tetrachlorosucralose-6-acetate.
  • the present invention has no special restrictions on the preparation method of the raw material liquid, and a preparation method for preparing a crude sucrose-6-acetate product using sucrose as an initial raw material well known to those skilled in the art can be used, specifically: using sucrose as a raw material, N, N-dimethylformamide (DMF) as a solvent, organic tin as a catalyst, and acetic anhydride as an acylating agent to prepare a solution containing sucrose-6-acetate; then the obtained solution containing sucrose-6-acetate is sequentially chlorinated (sulfoxyl chloride), neutralized with ammonia water, vacuum concentrated to dryness and dissolved in water to obtain a raw material liquid.
  • sucrose sucrose
  • N, N-dimethylformamide (DMF) as a solvent
  • organic tin organic tin
  • acetic anhydride as an acylating agent
  • the content of sucralose-6-acetate is preferably 50-80 g/L, more preferably 55-75 g/L; the mass ratio of sucralose-6-acetate, sucralose diester and tetrachlorosucrose-6-acetate in the raw material solution is preferably 1:0.06-0.15:0.06-0.15; the raw material solution preferably also includes NH 4 Cl and organic impurities, and the concentration of the NH 4 Cl is preferably 80-150 g/L, more preferably 80-100 g/L; the concentration of the organic impurities is preferably 30-80 g/L, more preferably 30-50 g/L.
  • the temperature of the ethyl acetate extraction is preferably 40-60°C, more preferably 45-55°C, and further preferably 50°C; the present invention has no special limitation on the number of ethyl acetate extractions, and the content of sucralose-6-acetate in the aqueous phase (i.e., the first aqueous phase) obtained by the last ethyl acetate extraction is less than 0.1 g/L, specifically 5-8 times; the time of a single ethyl acetate extraction is preferably 10-30 min, more preferably 15-20 min; the volume ratio of the raw material liquid to the ethyl acetate used for the single ethyl acetate extraction is preferably 1:0.2-0.5, more preferably 1:0.3-0.4.
  • the ethyl ester phase obtained by ethyl acetate extraction is combined into the first ethyl ester phase, and the raffinate phase obtained by the last ethyl acetate extraction is the first aqueous phase, and the first aqueous phase is preferably subjected to high-salt wastewater treatment.
  • the present invention uses hot ethyl acetate (40-60°C) to extract the raw material liquid, which can reduce the amount of ethyl acetate used and increase the amount of fat-soluble impurities dissolved, so as to increase the subsequent solubility of sucralose in ethyl acetate, thereby improving the crystal sugar content and the sucralose crystallization yield.
  • the present invention has no special limitation on the concentration method, and a concentration method well known to those skilled in the art can be used, such as vacuum concentration, wherein the concentration temperature is preferably 60 to 80° C., more preferably 65 to 75° C., and the concentration vacuum degree is preferably -0.1 to -0.08 MPa (gauge pressure), more preferably -0.09 to -0.08 MPa (gauge pressure).
  • concentration time is performed until the ethyl acetate content in the obtained first ethyl ester phase concentrate is ⁇ 0.5 g/L.
  • the present invention can avoid the generation of byproducts such as acetic acid and ethanol from ethyl acetate in the subsequent alkaline hydrolysis step by controlling the residual amount of ethyl acetate in the first ethyl ester phase concentrate, thereby further improving the purity and yield of sucralose.
  • the present invention mixes and dissolves the first ethyl ester phase concentrate with water, and concentrates to obtain a sucralose-6-acetate aqueous solution.
  • the volume ratio of the raw material liquid to water is preferably 1:0.5-1, and more preferably 1:0.6-0.8.
  • the present invention has no special restrictions on the concentration method, and a concentration method well known to those skilled in the art can be used, such as vacuum concentration, the concentration temperature is preferably 60-80°C, more preferably 65-75°C, the concentration vacuum is preferably -0.1-0.08MPa (gauge pressure), more preferably -0.09-0.08MPa (gauge pressure), the present invention has no special restrictions on the concentration time, and the content of ethyl acetate in the obtained sucralose-6-acetate aqueous solution is ⁇ 0.5g/L.
  • a concentration method well known to those skilled in the art can be used, such as vacuum concentration
  • the concentration temperature is preferably 60-80°C, more preferably 65-75°C
  • the concentration vacuum is preferably -0.1-0.08MPa (gauge pressure), more preferably -0.09-0.08MPa (gauge pressure)
  • the present invention has no special restrictions on the concentration time, and the content of ethyl acetate in the obtained sucralose-6-
  • the present invention can avoid the generation of byproducts such as acetic acid and ethanol from ethyl acetate in the subsequent alkaline hydrolysis step by controlling the residual amount of ethyl acetate in the sucralose-6-acetate aqueous solution, thereby further improving the purity and yield of sucralose.
  • the pulping mother liquor is preferably used to prepare the crude sucralose, and more preferably used to dissolve the first ethyl ester phase concentrate.
  • the present invention mixes the aqueous solution of sucralose-6-acetate with an alkali metal hydroxide, performs an alkaline hydrolysis reaction, neutralizes the obtained reaction solution, and then filters to obtain a second aqueous phase.
  • the alkali metal hydroxide preferably includes sodium hydroxide and/or potassium hydroxide; the alkali metal hydroxide is preferably used in the form of an alkali metal hydroxide aqueous solution, and the concentration of the alkali metal hydroxide aqueous solution is preferably 10-40wt%, more preferably 20-35wt%; the present invention has no special limitation on the amount of the alkali metal hydroxide, and the pH value during the alkaline hydrolysis reaction can be ensured to be 11-13, and the pH value is more preferably 11.5-12.5, and more preferably 12; the temperature of the alkaline hydrolysis reaction is preferably 0-10°C, more preferably 0-8°C, and more preferably 1-5°C; the time of the alkaline hydrolysis reaction is preferably 3-6h, more preferably 3.5-5.5h, and more preferably 4-5h.
  • the present invention performs alkaline hydrolysis under the above conditions, sucralose diester can be hydrolyzed to generate sucralose, sucralose-6-acetate can be dechlorinated and hydrolyzed to generate sucralose, and the by-products caused by the excessively high pH value of the alkaline hydrolysis reaction or the excessively high temperature of the alkaline hydrolysis reaction can be avoided.
  • sucralose diester can be hydrolyzed to generate sucralose
  • sucralose-6-acetate can be dechlorinated and hydrolyzed to generate sucralose
  • the by-products caused by the excessively high pH value of the alkaline hydrolysis reaction or the excessively high temperature of the alkaline hydrolysis reaction can be avoided.
  • the yield of sucralose is significantly improved, and there is no need to purify the crude aqueous solution of sucralose-6-acetate, which greatly shortens the process flow and reduces the production cost.
  • the neutralization acid preferably includes hydrochloric acid, and the concentration of the hydrochloric acid is preferably 15-35wt%, more preferably 20-30wt%.
  • the present invention has no special limitation on the amount of the acid, and the system can be neutralized to a pH value of 6.8-7.
  • the neutralization and filtration temperatures are independently preferably 50-70°C, more preferably 55-65°C, and further preferably 60°C. After alkaline hydrolysis is completed, a viscous substance is generated, and a large amount of sucralose is mixed in the viscous substance.
  • the reaction liquid obtained by the alkaline hydrolysis reaction is heated to 50-70° C.
  • sucralose mixed in the viscous substance can be dissolved, and then hot filtration can be performed to remove insoluble substances such as carbon residue and tar, and at the same time, the sucralose can be prevented from being caramelized due to excessive temperature.
  • the present invention extracts the second aqueous phase with ethyl acetate to obtain a second ethyl ester phase and a third aqueous phase, respectively.
  • the number of ethyl acetate extractions is preferably 4 to 7 times;
  • the volume ratio of the second aqueous phase to the single ethyl acetate extraction with ethyl acetate is preferably 1:1 to 3, more preferably 1:1.5 to 2.5;
  • the present invention preferably combines the ethyl ester phases obtained by the 1st to 2nd ethyl acetate extractions as the second ethyl ester phase;
  • the ethyl ester phases obtained by the 3rd to 7th ethyl acetate extractions are preferably used for the ethyl acetate extraction of the second aqueous phase in the next batch of crude sucralose preparation process.
  • the ethyl ester phase obtained by the 3rd ethyl acetate extraction is used for the 1st ethyl acetate extraction of the second aqueous phase in the next batch of crude sucralose preparation process
  • the ethyl ester phase obtained by the 4th ethyl acetate extraction is used for the 2nd ethyl acetate extraction of the second aqueous phase in the next batch of crude sucralose preparation process
  • the ethyl ester phase obtained by the 5th ethyl acetate extraction is used for the 6th ethyl acetate extraction of the second aqueous phase in the next batch of crude sucralose preparation process.
  • the ethyl ester phase obtained by the ethyl ester extraction is used for the third ethyl ester extraction of the second aqueous phase in the preparation process of the next batch of crude sucrose
  • the ethyl ester phase obtained by the sixth ethyl ester extraction is used for the fourth ethyl ester extraction of the second aqueous phase in the preparation process of the next batch of crude sucrose
  • the ethyl ester phase obtained by the seventh ethyl ester extraction is used for the fifth ethyl ester extraction of the second aqueous phase in the next batch
  • the ethyl ester phases obtained by the third to seventh ethyl ester extractions are used in sequence for the first to fifth ethyl ester extractions of the second aqueous phase in the preparation process of the next batch of crude sucralose
  • the present invention washes the second ethyl ester phase with water to obtain a fourth aqueous phase and a third ethyl ester phase, respectively; the fourth aqueous phase is reused in step (b) to dissolve the first ethyl ester phase concentrate.
  • the number of water washings is preferably 3 to 6 times; the volume ratio of the second ethyl ester phase to the single water used for washing is preferably 1:0.1 to 0.3, more preferably 1:0.15 to 0.25; the present invention preferably uses the aqueous phase obtained by the first water washing as the fourth aqueous phase, and preferably uses the aqueous phase obtained by the second to sixth water washings for the washing of the second ethyl ester phase in the next batch of crude sucralose preparation process.
  • the aqueous phase obtained by the second water washing is used for the first water washing of the second ethyl ester phase in the next batch of crude sucralose preparation process, and the aqueous phase obtained by the third water washing is used in the next batch of crude sucralose preparation process.
  • the aqueous phase obtained by the 4th water washing is used for the 3rd water washing of the second ethyl ester phase in the preparation process of the next batch of crude sucrose
  • the aqueous phase obtained by the 5th water washing is used for the 4th water washing of the second ethyl ester phase in the preparation process of the next batch of crude sucralose
  • the aqueous phase obtained by the 6th water washing is used for the 5th water washing of the second ethyl ester phase in the preparation process of the next batch of crude sucralose (that is, the aqueous phases obtained by the 2nd to 6th water washings are used sequentially for the 1st to 5th water washings of the third ethyl ester phase in the preparation process of the next batch of crude sucralose).
  • the 6th water washing of the second ethyl ester phase of the next batch of crude sucralose is preferably carried out with pure water.
  • the present invention mixes the third ethyl ester phase with ethyl acetate, performs azeotropic dehydration, and obtains a third ethyl ester phase concentrate; the third ethyl ester phase concentrate is mixed with ethyl acetate to obtain a fourth ethyl ester phase.
  • the present invention has no special restrictions on the concentration method, and a concentration method well known to those skilled in the art can be used, such as vacuum concentration, the concentration temperature is preferably 60 to 80°C, more preferably 65 to 75°C, the concentration vacuum is preferably -0.1 to -0.08MPa (gauge pressure), more preferably -0.09 to -0.08MPa (gauge pressure), the present invention has no special restrictions on the concentration time, and the water content of the third ethyl ester phase concentrate is ⁇ 0.5wt%.
  • the present invention has no special restrictions on the amount of ethyl acetate used, and the sugar content of the fourth ethyl ester phase is 40 to 60%, and the sugar content is more preferably 45 to 55%.
  • the present invention crystallizes the fourth ethyl ester phase to obtain crude sucralose and the fifth ethyl ester phase, respectively.
  • the crystallization temperature is preferably 40-60°C, more preferably 45-55°C; the crystallization time is preferably 12-30h, more preferably 15-25h.
  • the solubility of sucralose in ethyl acetate is low.
  • the present invention introduces fat-soluble caramel impurities in the system into ethyl acetate during the recycling of the fourth and fifth aqueous phases, which can significantly increase the solubility of sucralose in ethyl acetate, and uses extraction, water washing, and recycling to balance the impurities in the system, so that sucralose is enriched and crystallized in ethyl acetate.
  • the present invention crystallizes sucralose under the above temperature conditions, which has the following two major advantages: first, more sucralose can be obtained without more fat-soluble impurities; second, sucralose will not be caramelized due to the high crystallization temperature, thereby improving the yield of sucralose.
  • the present invention preferably further comprises solid-liquid separation to obtain crude sucralose and a fifth ethyl ester phase, respectively.
  • the present invention has no particular limitation on the solid-liquid separation method, and a solid-liquid separation method well known to those skilled in the art can be used, such as filtration, suction filtration or filter press.
  • the present invention washes the fifth ethyl ester phase with water to obtain a fifth aqueous phase and a sixth ethyl ester phase, respectively; the fifth aqueous phase is reused in step (b) to dissolve the first ethyl ester phase concentrate.
  • the present invention has no special limitation on the number of water washings, and the sucralose content in the sixth ethyl ester phase obtained by the last water washing is ⁇ 0.1 g/L, specifically 4 to 8 times.
  • the volume ratio of the fifth ethyl ester phase to the single water used for washing is preferably 1:0.5 to 1, and more preferably 1:0.6 to 0.8.
  • the sixth ethyl ester phase is preferably concentrated to obtain recovered ethyl acetate and sugar residue, and the sugar residue is preferably treated as solid waste.
  • the solubility of sucralose in water is relatively high.
  • the present invention can recover the uncrystallized sucralose into the fifth aqueous phase by water washing, and the fifth aqueous phase is recycled, which can improve the yield of sucralose and recover it for reuse.
  • the fat-soluble impurities in the sucralose crystals can be removed to improve its purity.
  • Water-soluble impurities and fat-soluble impurities are all produced by sucrose in a series of reaction processes, so they have a similar main structure to sucralose, so that there is a certain mutual solubility between water-soluble impurities, fat-soluble impurities and sucralose.
  • the present invention utilizes the relationship between the three, and selects water and ethyl acetate as solvents for removing water-soluble impurities and fat-soluble impurities, so that both solvents can dissolve and carry sucralose, realize the exchange of sucralose in the two solvents, and enrich sucralose in ethyl acetate, and crystallize therefrom to obtain crude sucralose.
  • the solubility of sucralose in ethyl acetate is much smaller than that in water, so in the pretreatment process, the present invention retains more fat-soluble impurities in the system.
  • multiple times and multiple times of ethyl acetate are used to extract sucralose from the alkaline hydrolysis solution.
  • the concentration of sucralose in the ethyl acetate extracted multiple times shows a gradient decline phenomenon, and the sucralose content in the ethyl acetate phase obtained by the first two extractions is relatively high, which is used as the raw material for sucralose crystallization.
  • the remaining batch of ethyl acetate phase is used for extraction of the next batch of alkaline hydrolyzate, so that a saturated ethyl acetate solution of sucralose can be obtained.
  • the content of water-soluble impurities will affect the crystallization of sucralose in the ethyl acetate phase. Therefore, the first two ethyl acetate phases containing sucralose need to be washed with a small amount of pure water multiple times to remove the water-soluble impurities therein.
  • the concentration of sucralose in the aqueous phase obtained by washing also decreases with the increase of the number of washings.
  • the washing liquid (the fourth aqueous phase) with the highest concentration of sucralose after the first washing is reused to mix and dissolve with the first ethyl ester phase concentrate, and the remaining washing liquid is used for washing the second ethyl ester phase of the next batch of sucralose.
  • the purpose of the concentrated drying treatment of the third ethyl ester phase obtained after washing is to remove the moisture in the system, because the residual moisture will increase the difficulty of crystallization of sucralose in ethyl acetate.
  • fresh ethyl acetate needs to be added to continue concentrated drying in order to remove moisture.
  • fresh ethyl acetate is used to dissolve the third ethyl ester concentrate to a specific sugar content, and the fourth ethyl ester phase obtained can be crystallized to obtain crude sucralose.
  • the present invention concentrates the target product liquid of beating and decolorizing, and performs the first crystallization on the obtained concentrated solution of the target product of beating and decolorizing, respectively obtaining the first crystallization target product and the primary crystallization mother liquor.
  • the concentration temperature is preferably 60-80°C, more preferably 65-75°C;
  • the concentration vacuum is preferably -0.1-0.08MPa (gauge pressure), more preferably -0.09-0.08MPa (gauge pressure);
  • the present invention has no special limitation on the concentration time, and the obtained concentrated solution of the target product of beating and decolorizing has a sugar content of 40-65%, and the sugar content is more preferably 45-60%, and further preferably 50-55%; the present invention is concentrated under the above conditions, which can avoid high-temperature coking of sucralose; the target product of beating and decolorizing has a sugar content that is too large or too small, and it is not easy to crystallize.
  • the temperature of the first crystallization is preferably room temperature, and the time of the first crystallization is preferably 8-16h, more preferably 10-15h, and further preferably 12-13h.
  • the present invention preferably further comprises subjecting the obtained first crystallization system to solid-liquid separation to obtain the first crystallization target product and the primary crystallization mother liquor, respectively.
  • the present invention does not specifically limit the solid-liquid separation method, and can adopt a solid-liquid separation method well known to those skilled in the art, such as filtration, suction filtration or filter press.
  • the primary crystallization mother liquor is preferably reused to prepare the crude sucralose, and more preferably used for azeotropic dehydration after mixing with the third ethyl ester.
  • the present invention dissolves the first crystallized target product in water, and performs a second crystallization on the obtained first crystallized target product aqueous solution to obtain a second crystallized target product and a secondary crystallization mother liquor, respectively; the secondary crystallization mother liquor is recycled to step (1) for dissolving the pulping target product.
  • the dissolution temperature is preferably 40 to 60°C, more preferably 45 to 55°C, and further preferably 50°C.
  • the sugar content of the first crystallized target product aqueous solution is preferably 40 to 65%, more preferably 45 to 60%, and further preferably 50 to 55%.
  • the temperature of the second crystallization is preferably room temperature, and the time of the second crystallization is preferably 8 to 16 hours, more preferably 10 to 15 hours, and further preferably 12 to 13 hours.
  • the present invention preferably further includes performing solid-liquid separation on the obtained second crystal system to obtain a second crystallized target product and a secondary crystallization mother liquor, respectively.
  • the present invention does not specifically limit the solid-liquid separation method, and a solid-liquid separation method well known to those skilled in the art can be used, such as filtration, suction filtration or filter pressing.
  • the present invention dissolves the second crystalline target product in water, decolorizes the obtained second crystalline target product aqueous solution with activated carbon, and then separates the solid and liquid to obtain the second crystalline decolorized target product aqueous solution and the recovered activated carbon respectively; the second crystalline decolorized target product aqueous solution is concentrated, and the obtained second crystalline decolorized target product concentrated solution is subjected to the third crystallization to obtain the third crystalline target product and the tertiary crystallization mother liquor respectively; the third crystalline target product is dried to obtain sucralose fine product; the tertiary crystallization mother liquor is reused in step (3) for dissolving the first crystalline target product, and the recovered activated carbon is reused in step (1) for decolorizing the pulping target product aqueous solution with activated carbon.
  • the dissolution temperature is preferably 40 to 60°C, more preferably 45 to 55°C, and further preferably 50°C.
  • the sugar content of the second crystalline target product aqueous solution is preferably 20 to 30%, more preferably 22 to 28%, and further preferably 24 to 26%.
  • the activated carbon is preferably plant activated carbon, more preferably including at least one of coconut shell activated carbon and fruit shell activated carbon. Coal-based activated carbon will have residual sulfur impurities, which will affect the taste of sucralose products.
  • the plant activated carbon used in the present invention has a low sulfur content and will not affect the product quality of sucralose.
  • the mass of the activated carbon is preferably 0.5-1% of the dry weight of the crude sucralose, more preferably 0.6-0.9%, and further preferably 0.7-0.8%;
  • the temperature of the activated carbon decolorization is preferably 40-50°C, more preferably 45°C, and the time of the activated carbon decolorization is preferably 5-10min, more preferably 6-8min.
  • the purpose of the activated carbon decolorization is to remove residual water-soluble impurities and improve the purity and quality of sucralose products.
  • the present invention does not specifically limit the solid-liquid separation method, and the solid-liquid separation method well known to those skilled in the art can be used, such as filtration, suction filtration or filter pressing.
  • the concentration temperature is preferably 60 to 80°C, more preferably 65 to 75°C
  • the concentration vacuum is preferably -0.1 to -0.08MPa (gauge pressure), more preferably -0.09 to -0.08MPa (gauge pressure)
  • the present invention has no special restrictions on the concentration time, and the concentration is performed until the sugar content of the obtained second crystal decolorization target product concentrate is 40 to 65%, and the sugar content is more preferably 45 to 60%, and further preferably 50 to 55%.
  • the temperature of the third crystallization is preferably 30 to 50°C, more preferably 35 to 45°C
  • the time of the third crystallization is preferably 4 to 12h, more preferably 5 to 10h.
  • the present invention preferably further includes solid-liquid separation of the obtained crystal system to obtain the third crystallization target product and the tertiary crystallization mother liquor respectively.
  • the present invention has no special restrictions on the solid-liquid separation method, and the solid-liquid separation method well known to those skilled in the art can be used, such as filtration, suction filtration or filter pressing.
  • the drying temperature is preferably 40 to 50° C., more preferably 45° C.
  • the drying time is preferably 8 to 12 h, more preferably 10 h.
  • HPLC high performance liquid chromatography
  • the preparation method of the raw material solution (referred to as the first aqueous solution) used in the following examples and comparative examples is as follows: sucrose is used as a raw material, DMF is used as a solvent, organotin is used as a catalyst, and acetic anhydride is used as an acylating agent to prepare a solution containing sucrose-6-acetate; then the obtained solution containing sucrose-6-acetate is sequentially chlorinated (sulfoxide chloride), neutralized with ammonia water, concentrated to dryness in vacuo, and dissolved in water to obtain a raw material solution.
  • sucrose is used as a raw material
  • DMF is used as a solvent
  • organotin is used as a catalyst
  • acetic anhydride is used as an acylating agent to prepare a solution containing sucrose-6-acetate
  • the obtained solution containing sucrose-6-acetate is sequentially chlorinated (sulfoxide chloride), neutralized with ammonia water, concentrated to dryness in vacu
  • Extraction step add 0.9L ethyl acetate to 3L first aqueous solution, stir and extract at 50°C for 15min, separate the phases to obtain an organic phase and an aqueous phase, repeat the above extraction step 6 times for the aqueous phase, after the extraction is completed, combine the ester phases as the first ethyl ester phase, and the aqueous phase obtained from the last extraction is the first aqueous phase (the content of sucralose-6-acetate is 0.07g/L, and the first aqueous phase is subjected to high-salt wastewater treatment).
  • the composition of the first aqueous solution is shown in Table 1:
  • the aqueous phase obtained from the first water washing is the fourth aqueous phase
  • the fourth aqueous phase is used in step (2) to replace water and mix with the first ethyl ester phase concentrate
  • the aqueous phases obtained from the 2nd to 6th water washings are used in sequence for the 1st to 5th water washings of the second ethyl ester phase in the preparation process of the next batch of crude sucralose, and the ester phase obtained after the washing is the third ethyl ester phase.
  • the third ethyl ester phase was concentrated and dried at 70° C. and ⁇ 0.1 MPa (gauge pressure).
  • Crystallization step crystallize the fourth ethyl ester phase at 45° C. for 24 h, filter and obtain crude sucralose and 1.3 L of the fifth ethyl ester phase (after equilibration four times); wash the fifth ethyl ester phase with water for 6 times (each time with 0.6 L of water), the ester phase after washing with water is the sixth ester phase (sucralose content 0.02 g/L), concentrate and dry the sixth ester phase to obtain recovered ethyl acetate and sugar residue; combine the aqueous phases as the fifth aqueous phase, and use the fifth aqueous phase in step (2) to replace water and mix with the first ethyl ester phase concentrate.
  • the beating mother liquor is reused in step (2) to dissolve the first ethyl ester phase concentrate; dissolve the beating target product in water at 45°C, add coconut shell activated carbon to the obtained beating target product aqueous solution (sugar content of 20%), and decolorize for 10 minutes at 40°C to obtain a beating and decolorizing target product liquid; wherein the ratio of the dry weight of the crude sucralose to the volume of ethyl acetate is 1kg:1L; the mass of the coconut shell activated carbon is 0.5% of the dry weight of the crude sucralose.
  • Second crystallization The first crystallization target product is placed in water and dissolved at 60°C.
  • the obtained first crystallization target product aqueous solution (sugar content is 65%) is subjected to second crystallization at room temperature for 8 hours to obtain a second crystallization target product and a secondary crystallization mother liquor, respectively; the secondary crystallization mother liquor is returned to step (6) to dissolve the pulping target product.
  • step (1) to (9) Recycling: According to the operations of steps (1) to (9) (recorded as recycling 0 times), the aqueous phases obtained by washing the fourth aqueous phase, the fifth aqueous phase, the second ethyl ester phase for the second to sixth times, and the ester phase obtained by extracting the second aqueous phase for the third to sixth times with ethyl acetate were recycled 17 times, wherein the step (2) of "adding water (1800 mL) to the obtained first ethyl ester phase concentrate and mixing" was modified to "mixing the obtained first ethyl ester phase, the fourth aqueous phase, the fifth aqueous phase and the pulping mother liquor"; the step (4) of "adding ethyl acetate to the obtained third ethyl ester phase concentrate to adjust the sugar content Bx to 43%” was replaced by "adding the primary crystallization mother liquor to the obtained third ethyl ester phase concentrate, concentrating it to a water content
  • Yield mass of sucralose/mass of sucralose-6-acetate completely converted to sucralose ⁇ 100%.
  • both sucralose diester and sucralose-6-acetate can be converted into sucralose after alkaline hydrolysis, and the theoretical maximum yield in Example 1 is 117.48%.
  • each mother liquor needs to be recycled at least 4 times to achieve a stable yield of sucralose fine product. After 17 cycles, the yield is still above 116%.
  • the sucralose concentrate was prepared according to the method of Example 1, which differed from Example 1 in that:
  • the aqueous phase obtained from the first water washing is the fourth aqueous phase
  • the fourth aqueous phase is used in step (2) to replace water and mix with the first ethyl ester phase concentrate
  • the aqueous phases obtained from the 2nd to 6th water washings are used in sequence for the 1st to 5th water washings of the second ethyl ester phase in the preparation process of the next batch of crude sucralose, and the ester phase obtained after the washing is the third ethyl ester phase.
  • the third ethyl ester phase was concentrated and dried at 75° C. and ⁇ 0.1 MPa (gauge pressure).
  • ethyl acetate was added (3 times, 0.8 L each time) to perform dehydration to ensure that the water was completely removed.
  • Ethyl acetate was added to the obtained third ethyl ester phase concentrate to adjust the sugar content Bx to 44%, thereby obtaining a fourth ethyl ester phase.
  • Crystallization step crystallize the fourth ethyl ester phase at 40° C. for 20 h, filter and obtain crude sucralose and 1.3 L of the fifth ethyl ester phase (after equilibration four times); wash the fifth ethyl ester phase with water for 6 times (each time with 0.55 L of water), the ester phase after washing with water is the sixth ester phase (sucralose content 0.06 g/L), concentrate and dry the sixth ester phase to obtain recovered ethyl acetate and sugar residue; combine the aqueous phases as the fifth aqueous phase, and use the fifth aqueous phase in step (2) to replace water and mix with the first ethyl ester phase concentrate.
  • step (6) the volume ratio of the crude sucralose dry weight to ethyl acetate is 1 kg:1.5 L, and the sugar content of the slurry target product aqueous solution is 30%.
  • step (7) the concentrate is concentrated at 60° C. and ⁇ 0.1 MPa (gauge pressure), the sugar content of the pulped and decolorized target product concentrate is 50%, and the first crystallization time is 16 h.
  • step (8) the dissolution temperature is 50° C., the sugar content of the first crystallization target product aqueous solution is 55%, and the second crystallization time is 12 h.
  • step (9) the dissolution temperature is 40°C
  • the sugar content of the aqueous solution of the second crystallization target product is 20%
  • the mass of the activated carbon is 0.5% of the dry weight of the crude sucralose
  • the decolorization time is 10 min
  • the concentration is carried out at 70°C and -0.09 MPa (gauge pressure).
  • the sugar content of the concentrated solution of the second crystallization decolorization target product is 40%.
  • the third crystallization is carried out at 30°C for 12 hours and dried at 50°C for 8 hours.
  • step (10) the purity and yield data of the sucralose fine product obtained by recycling 17 times are shown in Table 4:
  • the sucralose concentrate was prepared according to the method of Example 1, which differed from Example 1 in that:
  • the aqueous phase obtained from the first water washing is the fourth aqueous phase
  • the fourth aqueous phase is used in step (2) to replace water and mix with the first ethyl ester phase concentrate
  • the aqueous phases obtained from the 2nd to 6th water washings are used in sequence for the 1st to 5th water washings of the second ethyl ester phase in the preparation process of the next batch of crude sucralose, and the ester phase obtained after the washing is the third ethyl ester phase.
  • the third ethyl ester phase was concentrated and dried at 80° C. and ⁇ 0.09 MPa (gauge pressure).
  • ethyl acetate was added (3 times, 0.8 L each time) for dehydration to ensure that the water was completely removed.
  • Ethyl acetate was added to the obtained third ethyl ester phase concentrate to adjust the sugar content Bx to 41%, thereby obtaining a fourth ethyl ester phase.
  • Crystallization step crystallize the fourth ethyl ester phase at 40° C. for 18 h, filter and obtain crude sucralose and 1.1 L of the fifth ethyl ester phase (after equilibration four times); wash the fifth ethyl ester phase with water for 6 times (each time with 0.55 L of water), the ester phase after washing with water is the sixth ester phase (sucralose content 0.07 g/L), concentrate and dry the sixth ester phase to obtain recovered ethyl acetate and sugar residue; combine the aqueous phases as the fifth aqueous phase, and use the fifth aqueous phase in step (2) to replace water and mix with the first ethyl ester phase concentrate.
  • step (6) the volume ratio of the crude sucralose dry weight to the ethyl acetate is 1 kg:1.2 L, and the sugar content of the slurry target product aqueous solution is 25%.
  • step (7) the concentrate is concentrated at 70° C. and ⁇ 0.09 MPa (gauge pressure), the sugar content of the pulped and decolorized target product concentrate is 65%, and the first crystallization time is 8 h.
  • step (8) the dissolution temperature is 40° C.
  • the sugar content of the first crystallization target product aqueous solution is 40%
  • the second crystallization time is 16 h.
  • step (9) the dissolution temperature is 60°C
  • the sugar content of the aqueous solution of the second crystallization target product is 30%
  • the mass of the activated carbon is 0.7% of the dry weight of the crude sucralose
  • the decolorization time is 8 minutes
  • the concentration is carried out at 80°C and -0.08 MPa (gauge pressure).
  • the sugar content of the concentrated solution of the second crystallization decolorization target product is 55%.
  • the third crystallization is carried out at 40°C for 8 hours and dried at 45°C for 10 hours.
  • step (10) the purity and yield data of the sucralose fine product obtained by recycling 17 times are shown in Table 6:
  • Mother liquor recycling is one of the important means to improve the yield of target product and reduce production cost.
  • the key to successful recycling is how to separate the impurities enriched in the repeated recycling process from the target product. Only by continuously separating the impurities from the target product and discharging them from the process system can the stable operation of the process be guaranteed. Therefore, in which step and in what way the impurities are separated and discharged is the focus of the process.
  • the present invention can effectively remove the impurities in the crude product and the impurities generated by oxidation during the recycling of the crystallization mother liquor through ethyl acetate pulping treatment, two different stages of activated carbon impurity removal, and the third crystallization, and discharge the system.
  • the present invention has found that if all the mother liquors produced during the purification of crude sucralose are recycled, it will lead to the enrichment of impurities, so that qualified sucralose products cannot be obtained, and the phenomenon of inability to crystallize will occur after repeated use.
  • the present invention uses part of the mother liquor (pulping mother liquor and primary crystallization mother liquor) to prepare crude sucralose, and part of the mother liquor (secondary crystallization mother liquor and tertiary crystallization mother liquor) is reused for the purification of crude sucralose, thereby realizing the recycling of mother liquors, and no phenomenon of inability to crystallize is found after repeated use, which significantly improves the yield of sucralose and reduces the loss of sucralose in the purification process.
  • the method for preparing the sucralose fine product of the present invention can be effectively combined with the method for preparing the crude sucralose by using a hydrolysis system, so that the mother liquor formed in the production process of the sucralose fine product can be recycled, the problem of mother liquor resource waste can be solved, the amount of waste liquid can be reduced, sucralose can be recovered to the maximum extent, the yield of sucralose can be significantly increased, and food-grade sucralose fine products in different forms can be prepared, which significantly reduces the production cost and has a high industrialization prospect.

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Abstract

本发明提供了一种三氯蔗糖精品的制备方法，涉及精细化工技术领域。本发明通过对三氯蔗糖粗品进行乙酸乙酯打浆处理，两次不同阶段的活性炭脱色除杂，以及三次结晶，可以有效将三氯蔗糖粗品中的杂质以及结晶母液套用过程中因氧化产生的杂质去除，解决结晶母液在循环利用过程中的杂质富集的问题，从而实现精制过程产生的结晶母液能够反复循环利用，降低三氯蔗糖在提纯过程中的损耗，显著提高三氯蔗糖的收率。进一步地，本发明提供的三氯蔗糖精品的制备方法能够与三氯蔗糖粗品的方法有效结合，可以实现三氯蔗糖精品在制作过程中形成的母液循环套用，显著增加了三氯蔗糖的收率，显著降低了生产成本，具有较高的工业化前景。

Description

一种三氯蔗糖精品的制备方法 技术领域
本发明涉及精细化工技术领域，特别涉及一种三氯蔗糖精品的制备方法。
背景技术
三氯蔗糖，俗称蔗糖素，外观为白色结晶粉末或颗粒，是一种以蔗糖为原料的新一代甜味剂，其甜度是蔗糖的600倍，口感纯正、不参与人体新陈代谢，可供糖尿病人、心脑血管疾病患者及老年人使用的“零卡”糖，其还具有稳定性好和安全性高等特点，被广泛应用于食品、饮料、日化和医药等多个领域。
目前，三氯蔗糖的生产工艺主要以蔗糖为原料经酯化得到蔗糖-6-乙酸酯，蔗糖-6-乙酸酯经氯化得到三氯蔗糖-6-乙酸酯，三氯蔗糖-6-乙酸酯经醇解后提纯得到三氯蔗糖精品。其中，蔗糖-6-乙酸酯的合成主要有原乙酸三甲酯工艺(例如中国专利CN106749440A、CN105254684A)和有机锡工艺(例如中国专利CN102639550A、CN1528772A)。三氯蔗糖-6-乙酸酯的合成主要为光气/固体光气工艺(CN103328495A、CN1660868A)和氯化亚砜工艺(例如中国专利CN101270136A、CN102417526A)。由三氯蔗糖-6-乙酸酯制备三氯蔗糖的方法较多，如甲醇钠法(例如中国专利CN101918421A、CN1176094A)，有机胺法(例如中国专利CN101260127A、CN112771060A、CN101260127A)，碱性离子交换树脂法(例如中国专利CN112409419A、CN102336787A)，碱金属氧化物法(例如中国专利CN113004345A、CN104004032A、CN112805291A)，碱金属氢氧化物法(例如中国专利CN1814609A、CN101012250A、CN102321122A)。
传统的三氯蔗糖精品的生产方式主要为：以三氯蔗糖-6-乙酸酯纯品(纯度在99％以上)为原料，经醇解(甲醇钠/甲醇)或碱解(液碱/水)制备三氯蔗糖粗品，再经纯化(乙酸丁酯萃取除杂，然后在水中结晶)获得三氯蔗糖精品，在纯化过程中，结晶母液进行循环利用，且在循环利用过程中需要进行浓缩。然而，上述纯化步骤会导致三氯蔗糖氧化，形成新 的杂质，新的杂质在结晶母液循环利用过程中发生富集，进而影响三氯蔗糖的结晶，此时结晶母液(约套用5次左右)不能再进行循环利用而只能进行废水处理。
发明内容
有鉴于此，本发明的目的在于提供一种三氯蔗糖精品的制备方法，本发明提供的方法中结晶母液能够循环利用多次且三氯蔗糖精品的收率高、纯度高。
为了实现上述发明目的，本发明提供以下技术方案：
本发明提供了一种三氯蔗糖精品的制备方法，包括以下步骤：
本发明提供了一种三氯蔗糖精品的制备方法，包括以下步骤：
(1)打浆脱色：将三氯蔗糖粗品与乙酸乙酯混合，进行打浆后固液分离，分别得到打浆母液和打浆目标产物；将所述打浆目标产物溶解于水中，将得到的打浆目标产物水溶液进行活性炭脱色，得到打浆脱色目标产物液；
(2)第一结晶：将所述打浆脱色目标产物液进行浓缩，将得到的打浆脱色目标产物浓缩液进行第一结晶，分别得到第一结晶目标产物和一次结晶母液；
(3)第二结晶：将所述第一结晶目标产物溶解于水中，将得到的第一结晶目标产物水溶液进行第二结晶，分别得到第二结晶目标产物和二次结晶母液；所述二次结晶母液回用于步骤(1)中用于溶解所述打浆目标产物；
(4)第三结晶：将所述第二结晶目标产物溶解于水中，将得到的第二结晶目标产物水溶液进行活性炭脱色后固液分离，分别得到第二结晶脱色目标产物水溶液和回收活性炭；将所述第二结晶脱色目标产物水溶液进行浓缩，将得到的第二结晶脱色目标产物浓缩液进行第三结晶，分别得到第三结晶目标产物和三次结晶母液；将所述第三结晶目标产物进行干燥，得到三氯蔗糖精品；所述三次结晶母液回用于步骤(3)中用于溶解所述第一结晶目标产物，所述回收活性炭回用于步骤(1)中用于对打浆目标产物水溶液进行活性炭脱色。
优选地，步骤(1)中，所述三氯蔗糖粗品包括以下质量百分含量的 组分：三氯蔗糖85～95％，三氯蔗糖-6-乙酸酯0.5～1％，乙酸乙酯1～3％，焦糖类杂质1～13.5％。
优选地，步骤(1)中，所述三氯蔗糖粗品的质量与打浆用乙酸乙酯的体积之比为1kg：1～1.5L。
优选地，步骤(1)中，所述溶解的温度为30～50℃；
所述打浆目标产物水溶液的糖度为20～40％。
优选地，步骤(2)中，所述打浆脱色目标产物浓缩液的糖度为40～65％。
优选地，步骤(2)中，所述第一结晶的温度为室温，时间为8～16h。
优选地，步骤(3)中，所述溶解的温度为40～60℃；
所述第一结晶目标产物水溶液的糖度为40～65％。
优选地，步骤(3)中，所述第二结晶的温度为室温，时间为8～16h。
优选地，步骤(4)中，所述溶解的温度为40～60℃；
所述第二结晶脱色目标产物水溶液的糖度为20～30％。
优选地，步骤(4)中，所述第二结晶脱色目标产物浓缩液的糖度为40～65％。
优选地，步骤(4)中，所述第三结晶的温度为30～50℃，时间为4～12h。
优选地，所述三氯蔗糖粗品的制备方法包括以下步骤：
(a)将原料液进行乙酸乙酯萃取，分别得到第一乙酯相和第一水相；将所述第一乙酯相进行浓缩，得到第一乙酯相浓缩物；所述原料液为包括三氯蔗糖-6-乙酸酯、三氯蔗糖双酯和四氯蔗糖-6-乙酸酯的水溶液；
(b)将所述第一乙酯相浓缩物与水混合溶解，进行浓缩，得到三氯蔗糖-6-乙酸酯水溶液；
(c)将所述三氯蔗糖-6-乙酸酯水溶液与碱金属氢氧化物混合，进行碱解反应，将得到的反应液进行中和后过滤，得到第二水相；
(d)将所述第二水相进行乙酸乙酯萃取，分别得到第二乙酯相和第三水相；
(e)将所述第二乙酯相进行水洗，分别得到第四水相和第三乙酯相；所述第四水相回用于步骤(b)中用于溶解所述第一乙酯相浓缩物；
(f)将所述第三乙酯相与乙酸乙酯混合，进行共沸除水，得到第三乙酯相浓缩物；将所述第三乙酯相浓缩物与乙酸乙酯混合，得到第四乙酯 相；
(g)将所述第四乙酯相进行结晶，分别得到三氯蔗糖粗品和第五乙酯相；
(h)将所述第五乙酯相进行水洗，分别得到第五水相和第六乙酯相；所述第五水相回用于步骤(b)用于溶解所述第一乙酯相浓缩物。
优选地，所述打浆母液和一次结晶母液回用于制备三氯蔗糖粗品。
优选地，所述回用时，打浆母液用于溶解所述第一乙酯相浓缩物，一次结晶母液与所述第三乙酯相混合后共沸除水。
优选地，所述第三水相、第四水相和第五水相中三氯蔗糖含量独立地<0.5g/L。
优选地，步骤(a)中，所述乙酸乙酯萃取的温度为40～60℃，萃取次数为5～8次；所述原料液与单次乙酸乙酯萃取用乙酸乙酯的体积比为1：0.2～0.5。
优选地，步骤(b)中，所述三氯蔗糖-6-乙酸酯水溶液中乙酸乙酯的含量＜0.5g/L。
优选地，步骤(c)中，所述碱解反应的pH值为11～13，温度为0～10℃，时间3～6h。
优选地，步骤(c)中，所述中和与过滤的温度独立地为50～70℃。
优选地，步骤(d)中，所述乙酸乙酯萃取的次数为4～7次；所述第二水相与乙酸乙酯萃取单次用乙酸乙酯的体积比为1：1～3；
将第1～2次乙酸乙酯萃取得到的乙酯相合并作为第二乙酯相；
将第3～7次乙酸乙酯萃取得到的乙酯相用于下一批次三氯蔗糖粗品制备过程中所述第二水相的乙酸乙酯萃取。
优选地，步骤(e)中，所述水洗的次数为3～6次；所述第二乙酯相与水洗的单次用水的体积比为1：0.1～0.3；
将第1次水洗得到的水相作为第四水相；
将第2～6次水洗得到的水相用于下一批次三氯蔗糖粗品制备过程中所述第二乙酯相的水洗。
优选地，步骤(f)中，所述第三乙酯相浓缩液的水含量＜0.5wt％。
优选地，步骤(f)中，所述第四乙酯相的糖度为40～60％。
优选地，步骤(g)中，所述结晶的温度为40～60℃，时间12～30h。
现有技术无法实现以三氯蔗糖粗品为原料到三氯蔗糖精品的过程中目标产品与杂质间的物料平衡问题，最终会导致母液循环套用几次后，会因为杂质过多而不得不舍弃。本发明提供的制备方法，通过对三氯蔗糖粗品进行乙酸乙酯打浆处理，两次不同阶段的活性炭脱色除杂，以及三次结晶，可以有效将三氯蔗糖粗品中的杂质以及结晶母液套用过程中因氧化产生的杂质去除，确保后续的结晶母液的稳定性，解决结晶母液在循环利用过程中的杂质富集的问题，从而实现精制过程产生的结晶母液能够反复循环利用，降低三氯蔗糖在提纯过程中的损耗，显著提高三氯蔗糖的收率。本发明通过将二次结晶母液回用于溶解所述打浆目标产物以及三次结晶母液回用于溶解所述第一结晶目标产物，能够使得二次结晶母液和三次结晶母液中残留的三氯蔗糖得到充分利用，减少了三氯蔗糖在结晶过程中造成的大量损耗，显著提高三氯蔗糖的收率。
进一步的，打浆母液中含有大量的脂溶性杂质以及部分三氯蔗糖，一次结晶母液中含有残余的三氯蔗糖，本发明通过将打浆母液和一次结晶母液用于制备所述三氯蔗糖粗品，能够避免三氯蔗糖的损失，提高三氯蔗糖的整体收率。本发明提供的制备方法能够有效实现三氯蔗糖粗品的制备与三氯蔗糖粗品提纯的有效结合，实现三氯蔗糖与杂质在提纯工艺中的平衡，实现母液的长期多次循环利用。
进一步的，本发明以碱金属氢氧化物-水体系下进行碱解，三氯蔗糖-6-乙酸酯、三氯蔗糖双酯和四氯蔗糖-6-乙酸酯均会在强碱水溶液存在的情况下碱解，生成对应的三氯蔗糖和四氯蔗糖，四氯蔗糖可以在强碱水溶液存在的情况下继续脱氯形成三氯蔗糖，使得原料液中的三氯蔗糖-6-乙酸酯以及杂质(三氯蔗糖双酯和四氯蔗糖-6-乙酸酯)均转换为三氯蔗糖，从而显著提高了原料转化率以及三氯蔗糖的收率，相对于以高纯度三氯蔗糖-6-乙酸酯为原料进行碱解制备三氯蔗糖的方法，本发明提供的方法中原料转化率和三氯蔗糖的收率显著提高。本发明采用乙酸乙酯-水的双重体系，可将实现双体系间的相互套用萃取除杂，富集三氯蔗糖，从而使三氯蔗糖能够在乙酸乙酯中大量结晶，并通过反复套用的方式回收三氯蔗糖，避免了三氯蔗糖的损失，大大提高了三氯蔗糖的整体收率。而且，与 传统的甲醇钠/甲醇体系水解相比，本发明提供的制备方法的生产成本低，安全环保。
附图说明
图1为三氯蔗糖精品的制备工艺流程图；
图2为利用水解体系制备三氯蔗糖粗品以及三氯蔗糖粗品的制备工艺流程图。
具体实施方式
下面结合实施例和附图对本发明进一步说明。
本发明提供了一种三氯蔗糖精品的制备方法，包括以下步骤：
(1)将三氯蔗糖粗品与乙酸乙酯混合，进行打浆后固液分离，分别得到打浆母液和打浆目标产物；将所述打浆目标产物溶解于水中，将得到的打浆目标产物水溶液进行活性炭脱色，得到打浆脱色目标产物液；
(2)将所述打浆脱色目标产物液进行浓缩，将得到的打浆脱色目标产物浓缩液进行第一结晶，分别得到第一结晶目标产物和一次结晶母液；
(3)将所述第一结晶目标产物溶解于水中，将得到的第一结晶目标产物水溶液进行第二结晶，分别得到第二结晶目标产物和二次结晶母液；所述二次结晶母液回用于步骤(1)中用于溶解所述打浆目标产物；
(4)将所述第二结晶目标产物溶解于水中，将得到的第二结晶目标产物水溶液进行活性炭脱色后固液分离，分别得到第二结晶脱色目标产物水溶液和回收活性炭；将所述第二结晶脱色目标产物水溶液进行浓缩，将得到的第二结晶脱色目标产物浓缩液进行第三结晶，分别得到第三结晶目标产物和三次结晶母液；将所述第三结晶目标产物进行干燥，得到三氯蔗糖精品；所述三次结晶母液回用于步骤(3)中用于溶解所述第一结晶目标产物，所述回收活性炭回用于步骤(1)中用于对打浆目标产物水溶液进行活性炭脱色。
在本发明中，若无特殊说明，所有的原料组分均为本领域技术人员熟知的市售商品。
本发明将三氯蔗糖粗品与乙酸乙酯混合，进行打浆后固液分离，分别得到打浆母液和打浆目标产物；将所述打浆目标产物溶解于水中，将得到的打浆目标产物水溶液与活性炭混合，进行脱色，得到打浆脱色目标产物 液；所述打浆母液用于制备三氯蔗糖粗品。
在本发明中，所述三氯蔗糖粗品包括以下质量百分含量的组分：三氯蔗糖优选为85～95％，更优选为88～92％；三氯蔗糖-6-乙酸酯优选为0.5～1％，更优选为0.6～0.9％；乙酸乙酯优选为1～3％，更优选为1.5～2.5％；焦糖类杂质优选为1～13.5％，更优选为5～10％。在本发明中，所述三氯蔗糖粗品的质量与打浆用乙酸乙酯的体积之比优选为1kg：1～1.5L，更优选为1kg：1.1～1.4L，进一步优选为1kg：1.3～1.4L。
在本发明中，所述打浆的温度优选为20～40℃，更优选为室温。所述打浆的时间优选为5～15min，更优选为10min；所述打浆优选在搅拌条件下进行。本发明对于所述固液分离的方式没有特殊限定，采用本领域技术人员熟知的固液分离方式即可，具体如过滤、抽滤或压滤。在本发明中，所述溶解的温度优选为30～50℃，更优选为30～45℃，进一步优选为30～40℃；所述打浆目标产物水溶液的糖度(Bx)优选为20～40％，更优选为25～35％，进一步优选为30％。
在本发明中，所述活性炭优选为植物活性炭，更优选包括椰壳活性炭和果壳活性炭中的至少一种，煤基活性炭会残留硫杂质，会影响三氯蔗糖的产品口感，而本发明采用的植物活性炭中硫含量低，不会影响三氯蔗糖的产品品质。在本发明中，所述活性炭的质量优选为三氯蔗糖粗品干重的0.5～1％，更优选为0.6～0.9％。在本发明中，所述脱色的温度优选为40～50℃，更优选为45℃，所述脱色的时间优选为5～10min，更优选为6～8min，所述活性炭脱色的目的是脱除三氯蔗糖粗品中的有色杂质。完成所述活性炭脱色后，本发明优选还包括将所得脱色体系进行固液分离，分别得到打浆脱色目标产物液和活性炭残渣。本发明对于所述固液分离的方式没有特殊限定，采用本领域技术人员熟知的固液分离方式即可，具体如过滤、抽滤或压滤。在本发明中，所述活性炭残渣优选进行固废处理。
在本发明中，所述三氯蔗糖粗品的制备方法优选包括以下步骤：
(a)将原料液进行乙酸乙酯萃取，分别得到第一乙酯相和第一水相；将所述第一乙酯相进行浓缩，得到第一乙酯相浓缩物；所述原料液为包括三氯蔗糖-6-乙酸酯、三氯蔗糖双酯和四氯蔗糖-6-乙酸酯的水溶液；
(b)将所述第一乙酯相浓缩物与水混合溶解，进行浓缩，得到三氯 蔗糖-6-乙酸酯水溶液；
(c)将所述三氯蔗糖-6-乙酸酯水溶液与碱金属氢氧化物混合，进行碱解反应，将得到的反应液进行中和后过滤，得到第二水相；
(d)将所述第二水相进行乙酸乙酯萃取，分别得到第二乙酯相和第三水相；
(e)将所述第二乙酯相进行水洗，分别得到第四水相和第三乙酯相；所述第四水相回用于步骤(b)中用于溶解所述第一乙酯相浓缩物；
(f)将所述第三乙酯相与乙酸乙酯混合，进行共沸除水，得到第三乙酯相浓缩物；将所述第三乙酯相浓缩物与乙酸乙酯混合，得到第四乙酯相；
(g)将所述第四乙酯相进行结晶，分别得到三氯蔗糖粗品和第五乙酯相；
(h)将所述第五乙酯相进行水洗，分别得到第五水相和第六乙酯相；所述第五水相回用于步骤(b)用于溶解所述第一乙酯相浓缩物。
本发明将原料液进行乙酸乙酯萃取，分别得到第一乙酯相和第一水相；将所述第一乙酯相进行浓缩，得到第一乙酯相浓缩物；所述原料液为包括三氯蔗糖-6-乙酸酯、三氯蔗糖双酯和四氯蔗糖-6-乙酸酯的水溶液。本发明对于所述原料液的制备方法没有特殊限定，采用本领域技术人员熟知的以蔗糖为初始原料制备蔗糖-6-乙酸酯粗品的制备方法即可，具体如：以蔗糖为原料，N,N-二甲基甲酰胺(DMF)为溶剂，有机锡为催化剂，乙酸酐为酰化剂，制得含有蔗糖-6-乙酸酯的溶液；然后将所得含有蔗糖-6-乙酸酯的溶液依次进行氯化(氯化亚砜)、氨水中和、真空浓缩至干和加水溶解，得到原料液。在本发明中，所述原料液中，三氯蔗糖-6-乙酸酯的含量优选为50～80g/L，更优选为55～75g/L；所述原料液中三氯蔗糖-6-乙酸酯、三氯蔗糖双酯和四氯蔗糖-6-乙酸酯的质量比优选为1：0.06～0.15：0.06～0.15；所述原料液中优选还包括NH 4Cl和有机杂质，所述所述NH 4Cl的浓度优选为80～150g/L，更优选为80～100g/L；所述有机杂质的浓度优选为30～80g/L，更优选为30～50g/L。在本发明中，所述乙酸乙酯萃取的温度优选为40～60℃，更优选为45～55℃，进一步优选为50℃；本发明对于所述乙酸乙酯萃取的次数没有特殊限定，以最后一次乙酸乙酯萃取得到 的水相(即第一水相)中三氯蔗糖-6-乙酸酯的含量＜0.1g/L为准，具体如5～8次；单次乙酸乙酯萃取的时间优选为10～30min，更优选为15～20min；所述原料液与单次乙酸乙酯萃取用乙酸乙酯的体积比优选为1：0.2～0.5，更优选为1：0.3～0.4。在本发明中，乙酸乙酯萃取所得乙酯相合并为第一乙酯相，最后一次乙酸乙酯萃取所得萃余相为第一水相，所述第一水相优选进行高盐废水处理。本发明采用热的乙酸乙酯(40～60℃)对原料液进行萃取，能够减少乙酸乙酯的使用量，同时增加脂溶性杂质的溶解量，以利于增加后续三氯蔗糖在乙酸乙酯中的溶解度，进而提高结晶糖度及三氯蔗糖结晶收率。本发明对于所述浓缩的方式没有特殊限定，采用本领域技术人员熟知的浓缩方式即可，具体如真空浓缩，所述浓缩的温度优选为60～80℃，更优选为65～75℃，所述浓缩的真空度优选为-0.1～-0.08MPa(表压)，更优选为-0.09～-0.08MPa(表压)，本发明对于所述浓缩的时间没有特殊限定，浓缩至所得第一乙酯相浓缩物中乙酸乙酯含量<0.5g/L即可。本发明通过控制第一乙酯相浓缩物中乙酸乙酯的残留量，能够避免在后续的碱解步骤中乙酸乙酯生成乙酸、乙醇等副产物，进一步提高了三氯蔗糖的纯度和收率。
得到第一乙酯相浓缩物后，本发明将所述第一乙酯相浓缩物与水混合溶解，进行浓缩，得到三氯蔗糖-6-乙酸酯水溶液。在本发明中，所述原料液与水的体积比优选为1：0.5～1，更优选为1：0.6～0.8。本发明对于所述浓缩的方式没有特殊限定，采用本领域技术人员熟知的浓缩方式即可，具体如真空浓缩，所述浓缩的温度优选为60～80℃，更优选为65～75℃，所述浓缩的真空度优选为-0.1～-0.08MPa(表压)，更优选为-0.09～-0.08MPa(表压)，本发明对于所述浓缩的时间没有特殊限定，浓缩至所得三氯蔗糖-6-乙酸酯水溶液中乙酸乙酯的含量＜0.5g/L即可。本发明通过控制三氯蔗糖-6-乙酸酯水溶液中乙酸乙酯的残留量，能够避免在后续的碱解步骤中乙酸乙酯生成乙酸、乙醇等副产物，进一步提高了三氯蔗糖的纯度和收率。在本发明中，所述打浆母液优选回用于制备所述三氯蔗糖粗品，更优选用于溶解所述第一乙酯相浓缩物。
得到三氯蔗糖-6-乙酸酯水溶液后，本发明将所述三氯蔗糖-6-乙酸酯水溶液与碱金属氢氧化物混合，进行碱解反应，将得到的反应液进行中和 后过滤，得到第二水相。在本发明中，所述碱金属氢氧化物优选包括氢氧化钠和/或氢氧化钾；所述碱金属氢氧化物优选以碱金属氢氧化物水溶液形式使用，所述碱金属氢氧化物水溶液的浓度优选为10～40wt％，更优选为20～35wt％；本发明对于所述碱金属氢氧化物的用量没有特殊限定，能够将保证碱解反应过程中pH值为11～13即可，所述pH值更优选为11.5～12.5，进一步优选为12；所述碱解反应的温度优选为0～10℃，更优选为0～8℃，进一步优选为1～5℃；所述碱解反应的时间优选为3～6h，更优选为3.5～5.5h，进一步优选为4～5h。本发明在上述条件下进行碱解反应，三氯蔗糖双酯能够发生水解生成三氯蔗糖，四氯蔗糖-6-乙酸酯能够发生脱氯以及水解反应生成三氯蔗糖，且还能够避免因碱解反应的pH值过高或碱解反应的温度过高而产生副产物。与以纯三氯蔗糖-6-乙酸酯为原料相比，三氯蔗糖的收率显著提高，而且无需对三氯蔗糖-6-乙酸酯粗品水溶液进行提纯，大大缩短了工艺流程并降低了生产成本。在本发明中，所述中和用酸优选包括盐酸，所述盐酸的浓度优选为优选为15～35wt％，更优选为20～30wt％。本发明对于所述酸的用量没有特殊限定，能够将体系中和至pH值为6.8～7即可。在本发明中，所述中和与过滤的温度独立地优选为50～70℃，更优选为55～65℃，进一步优选为60℃。碱解完成后会产生粘稠物，粘稠物中会夹杂大量的三氯蔗糖，本发明对碱解反应得到的反应液加热至50～70℃进行中和，能够使得粘稠物中夹杂的三氯蔗糖溶解，然后进行热过滤能够去除碳渣、焦油等不溶物，同时还能够避免温度过高导致三氯蔗糖焦化。
得到第二水相后，本发明将所述第二水相进行乙酸乙酯萃取，分别得到第二乙酯相和第三水相。在本发明中，所述乙酸乙酯萃取的次数优选为4～7次；所述第二水相与乙酸乙酯萃取单次用乙酸乙酯的体积比优选为1：1～3，更优选为1:1.5～2.5；本发明优选将第1～2次乙酸乙酯萃取得到的乙酯相合并作为第二乙酯相；优选将第3～7次乙酸乙酯萃取所得乙酯相用于下一批次三氯蔗糖粗品制备过程中第二水相的乙酸乙酯萃取，具体的，第3次乙酸乙酯萃取所得乙酯相用于下一批次三氯蔗糖粗品制备过程中第二水相的第1次乙酸乙酯萃取，第4次乙酸乙酯萃取所得乙酯相用于下一批次三氯蔗糖粗品制备过程中第二水相的第2次乙酸乙酯萃取，第5 次乙酸乙酯萃取所得乙酯相用于下一批次蔗糖粗品制备过程中第二水相的第3次乙酸乙酯萃取，第6次乙酸乙酯萃取所得乙酯相用于下一批次蔗糖粗品制备过程中第二水相的第4次乙酸乙酯萃取，第7次乙酸乙酯萃取所得乙酯相用于下一批次第二水相的第5次乙酸乙酯萃取(即第3～7次乙酸乙酯萃取所得乙酯相依次用于下一批次三氯蔗糖粗品制备过程中第二水相的第1～5次乙酸乙酯萃取)，下一批次三氯蔗糖粗品的第二水相的第6～7次乙酸乙酯萃取优选利用纯乙酸乙酯进行。在本发明中，所述第三水相中三氯蔗糖含量优选<0.5g/L。
得到第二乙酯相后，本发明将所述第二乙酯相进行水洗，分别得到第四水相和第三乙酯相；所述第四水相回用于步骤(b)中用于溶解所述第一乙酯相浓缩物。在本发明中，所述水洗的次数优选为3～6次；所述第二乙酯相与水洗的单次用水的体积比优选为1：0.1～0.3，更优选为1：0.15～0.25；本发明优选将第1次水洗得到的水相作为第四水相，优选将第2～6次水洗得到的水相用于下一批次三氯蔗糖粗品制备过程中第二乙酯相的水洗，具体的，第2次水洗所得水相用于下一批次三氯蔗糖粗品制备过程中第二乙酯相的第1次水洗，第3次水洗所得水相用于下一批次三氯蔗糖粗品制备过程中第二乙酯相的第2次水洗，第4次水洗所得水相用于下一批次蔗糖粗品制备过程中第二乙酯相的第3次水洗，第5次水洗所得水相用于下一批次三氯蔗糖粗品制备过程中第二乙酯相的第4次水洗，第6次水洗所得水相用于下一批次三氯蔗糖粗品制备过程中第二乙酯相的第5次水洗(即第2～6次水洗所得水相依次用于下一批次三氯蔗糖粗品制备过程中第三乙酯相的第1～5次水洗)，下一批次三氯蔗糖粗品的第二乙酯相的第6次水洗优选利用纯水进行。
得到第三乙酯相后，本发明将所述第三乙酯相与乙酸乙酯混合，进行共沸除水，得到第三乙酯相浓缩物；将所述第三乙酯相浓缩物与乙酸乙酯混合，得到第四乙酯相。本发明对于所述浓缩的方式没有特殊限定，采用本领域技术人员熟知的浓缩方式即可，具体如真空浓缩，所述浓缩的温度优选为60～80℃，更优选为65～75℃，所述浓缩的真空度优选为-0.1～-0.08MPa(表压)，更优选为-0.09～-0.08MPa(表压)，本发明对于所述浓缩的时间没有特殊限定，浓缩至所述第三乙酯相浓缩物的水含量＜ 0.5wt％即可。本发明对于所述乙酸乙酯的用量没有特殊限定，以所述第四乙酯相的糖度为40～60％为准，所述糖度更优选为45～55％。
得到第四乙酯相后，本发明将所述第四乙酯相进行结晶，分别得到三氯蔗糖粗品和第五乙酯相。在本发明中，所述结晶的温度优选为40～60℃，更优选为45～55℃；所述结晶的时间优选为12～30h，更优选为15～25h。三氯蔗糖在乙酸乙酯中的溶解度较低，本发明通过在第四水相和第五水相循环套用过程中，将体系中的脂溶性焦糖类杂质引入乙酸乙酯中，可显著增加三氯蔗糖在乙酸乙酯中的溶解度，并采用萃取、水洗、循环套用的方式使体系中的杂质达到平衡，从而使得三氯蔗糖在乙酸乙酯中富集并结晶。而且，本发明在上述温度条件下对三氯蔗糖进行结晶，具有以下两大优势：一是可获得较多的三氯蔗糖且不会夹杂较多的脂溶性杂质；二是不会因为结晶温度较高而导致三氯蔗糖焦化，从而提高了三氯蔗糖的收率。完成所述结晶后，本发明优选还包括固液分离，分别得到三氯蔗糖粗品和第五乙酯相。本发明对于所述固液分离的方式没有特殊限定，采用本领域技术人员熟知的固液分离方式即可，具体如过滤、抽滤或压滤。
得到第五乙酯相后，本发明将所述第五乙酯相进行水洗，分别得到第五水相和第六乙酯相；所述第五水相回用于步骤(b)用于溶解所述第一乙酯相浓缩物。本发明对于所述水洗的次数没有特殊限定，以最后一次水洗所得第六乙酯相中三氯蔗糖含量<0.1g/L为准，具体如4～8次。在本发明中，所述第五乙酯相与水洗的单次用水的体积比优选为1：0.5～1，更优选为1：0.6～0.8。在本发明中，所述第六乙酯相优选进行浓缩，得到回收乙酸乙酯和糖渣，所述糖渣优选进行固废处理。结晶完成后，第五乙酯相中脂溶性杂质较多，三氯蔗糖在水中的溶解度较高，本发明采用水洗的方式能够将未结晶的三氯蔗糖回收至第五水相中，将第五水相进行循环利用，能够提高三氯蔗糖的收率回收套用，同时还能够将三氯蔗糖晶体中的脂溶性杂质排除，提高其纯度。
水溶性杂质和脂溶性杂质均为蔗糖在一系列反应过程中产生的，因此与三氯蔗糖有类似的主体结构，从而使水溶性杂质、脂溶性杂质和三氯蔗糖之间均有一定的互溶度。本发明正是利用三者之间的关系，通过选用水和乙酸乙酯作为除去水溶性杂质和脂溶性杂质的溶剂，从而利用两种溶剂 均可以溶解、夹带三氯蔗糖，实现三氯蔗糖在两种溶剂中的交换，并使三氯蔗糖在乙酸乙酯中富集，并从中结晶获得三氯蔗糖粗品。具体的，三氯蔗糖在乙酸乙酯中的溶解度远小于在水中的溶解度，因此在前处理过程中，本发明将较多的脂溶性杂质保留在体系中。碱解反应后，采用多倍、多次的乙酸乙酯将三氯蔗糖从碱解液中萃取出来。此时，三氯蔗糖在多次萃取的乙酸乙酯中的浓度呈现梯度下降的现象，前两次萃取所得乙酸乙酯相中的三氯蔗糖含量较高，作为三氯蔗糖结晶的原料。剩余批次的乙酸乙酯相用于下一批次的碱解液的萃取，这样可以获得饱和的三氯蔗糖乙酸乙酯溶液。水溶性杂质的含量会影响三氯蔗糖在乙酸乙酯相中的结晶，因此，前两次的含有三氯蔗糖的乙酸乙酯相需要少量纯水多次水洗，从而去除其中的水溶性杂质。水洗所得水相中的三氯蔗糖浓度也随着水洗次数的增加而减少，为了回收此部分三氯蔗糖，将第一次水洗且含三氯蔗糖浓度最高的水洗液(第四水相)回用至与所述第一乙酯相浓缩物混合溶解，剩余水洗液用于下一批次三氯蔗糖第二乙酯相的水洗。水洗后所得第三乙酯相进行浓干处理的目的是除尽体系中的水分，这是由于水分的残留会增加三氯蔗糖在乙酸乙酯中结晶的难度。浓干之后还需要添加新鲜的乙酸乙酯继续浓干，目的是为了除尽水分，此时再用新鲜的乙酸乙酯溶解第三乙酯浓缩物至特定糖度，所得第四乙酯相即可结晶获得三氯蔗糖粗品。
得到打浆脱色目标产物液后，本发明将所述打浆脱色目标产物液进行浓缩，将得到的打浆脱色目标产物浓缩液进行第一结晶，分别得到第一结晶目标产物和一次结晶母液。在本发明中，所述浓缩的温度优选为60～80℃，更优选为65～75℃；所述浓缩的真空度优选为-0.1～-0.08MPa(表压)，更优选为-0.09～-0.08MPa(表压)；本发明对于所述浓缩的时间没有特殊限定，浓缩至所得打浆脱色目标产物浓缩液的糖度为40～65％即可，所述糖度更优选为45～60％，进一步优选为50～55％；本发明在上述条件下进行浓缩，能够避免三氯蔗糖发生高温焦化；打浆脱色目标产物浓缩液的糖度过大或过小均不易结晶。在本发明中，所述第一结晶的温度优选为室温，所述第一结晶的时间优选为8～16h，更优选为10～15h，进一步优选为12～13h。完成所述第一结晶后，本发明优选还包括将所得第一结晶体系进行固液分离，分别得到第一结晶目标产物和一次结晶母液。本发明 对于所述固液分离的方式没有特殊限定，采用本领域技术人员熟知的固液分离方式即可，具体如过滤、抽滤或压滤。在本发明中，所述一次结晶母液优选回用于制备所述三氯蔗糖粗品，更优选用于与所述第三乙酯相混合后进行共沸除水。
得到第一结晶目标产物后，本发明将所述第一结晶目标产物溶解于水中，将得到的第一结晶目标产物水溶液进行第二结晶，分别得到第二结晶目标产物和二次结晶母液；所述二次结晶母液回用于步骤(1)中用于溶解所述打浆目标产物。在本发明中，所述溶解的温度优选为40～60℃，更优选为45～55℃，进一步优选为50℃。在本发明中，所述第一结晶目标产物水溶液的糖度优选为40～65％，更优选为45～60％，进一步优选为50～55％。在本发明中，所述第二结晶的温度优选为室温，所述第二结晶的时间优选为8～16h，更优选为10～15h，进一步优选为12～13h。完成所述第二结晶后，本发明优选还包括将所得第二结晶体系进行固液分离，分别得到第二结晶目标产物和二次结晶母液。本发明对于所述固液分离的方式没有特殊限定，采用本领域技术人员熟知的固液分离方式即可，具体如过滤、抽滤或压滤。
得到第二结晶目标产物后，本发明将所述第二结晶目标产物溶解于水中，将得到的第二结晶目标产物水溶液进行活性炭脱色后固液分离，分别得到第二结晶脱色目标产物水溶液和回收活性炭；将所述第二结晶脱色目标产物水溶液进行浓缩，将得到的第二结晶脱色目标产物浓缩液进行第三结晶，分别得到第三结晶目标产物和三次结晶母液；将所述第三结晶目标产物进行干燥，得到三氯蔗糖精品；所述三次结晶母液回用于步骤(3)中用于溶解所述第一结晶目标产物，所述回收活性炭回用于步骤(1)中用于对打浆目标产物水溶液进行活性炭脱色。在本发明中，在本发明中，所述溶解的温度优选为40～60℃，更优选为45～55℃，进一步优选为50℃。在本发明中，所述第二结晶目标产物水溶液的糖度优选为20～30％，更优选为22～28％，进一步优选为24～26％。在本发明中，所述活性炭优选为植物活性炭，更优选包括椰壳活性炭和果壳活性炭中的至少一种，煤基活性炭会残留硫杂质，会影响三氯蔗糖的产品口感，而本发明采用的植物活性炭中硫含量低，不会影响三氯蔗糖的产品品质。在本发明中，所述活性 炭的质量优选为所述三氯蔗糖粗品干重的0.5～1％，更优选为0.6～0.9％，进一步优选为0.7～0.8％；所述活性炭脱色的温度优选为40～50℃，更优选为45℃，所述活性炭脱色的时间优选为5～10min，更优选为6～8min，所述活性炭脱色的目的是除去残余的水溶性杂质，提高三氯蔗糖精品的纯度和质量。本发明对于所述固液分离的方式没有特殊限定，采用本领域技术人员熟知的固液分离方式即可，具体如过滤、抽滤或压滤。在本发明中，所述浓缩的温度优选为60～80℃，更优选为65～75℃，所述浓缩的真空度优选为-0.1～-0.08MPa(表压)，更优选为-0.09～-0.08MPa(表压)，本发明对于所述浓缩的时间没有特殊限定，浓缩至所得第二结晶脱色目标产物浓缩液的糖度为40～65％即可，所述糖度更优选为45～60％，进一步优选为50～55％。在本发明中，所述第三结晶的温度优选为30～50℃，更优选为35～45℃，所述第三结晶的时间优选为4～12h，更优选为5～10h。完成所述第三结晶后，本发明优选还包括将所得结晶体系进行固液分离，分别得到第三结晶目标产物和三次结晶母液。本发明对于所述固液分离的方式没有特殊限定，采用本领域技术人员熟知的固液分离方式即可，具体如过滤、抽滤或压滤。在本发明中，所述干燥的温度优选为40～50℃，更优选为45℃，所述干燥的时间优选为8～12h，更优选为10h。
下面将结合本发明中的实施例，对本发明中的技术方案进行清楚、完整地描述。显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
以下各实施例和对比例中各物质的含量均采用高效液相色谱(High Performance Liquid Chromatography，HPLC)方法在下述条件下采用外标法测得，高效液相色谱的分析测定条件：日本岛津高效液相色谱仪，配RID-10A示差折光检测，LC-10ADVP高压泵，CTO-10ASVP恒温箱；色谱柱：Agilent XDB C18柱(250mm×4.6mm，5μm)；流动相：甲醇-0.125wt％磷酸氢二钾水溶液(4:6，v/v)；柱温：40℃；流动相流量：1.0mL/min；其中，甲醇(色谱纯)、磷酸氢二钾(分析纯)、水为超纯水。
以下实施例和对比例中使用的原料液(记为第一水溶液)的制备方法：使用蔗糖为原料，DMF为溶剂，有机锡为催化剂，乙酸酐为酰化剂，制 得含有蔗糖-6-乙酸酯的溶液；然后将所得含有蔗糖-6-乙酸酯的溶液依次进行氯化(氯化亚砜)、氨水中和、真空浓缩至干、加水溶解，得到原料液。
实施例1
采用图1～图2所示的工艺流程图制备三氯蔗糖精品，具体步骤如下：
(1)萃取步骤：在3L第一水溶液中加入0.9L乙酸乙酯，在50℃条件下搅拌萃取15min，分相，得到有机相和水相，将所述水相重复上述萃取步骤6次，萃取完成后，酯相合并作为第一乙酯相，最后一次萃取所得水相为第一水相(三氯蔗糖-6-乙酸酯含量为0.07g/L，第一水相进行高盐废水处理)。其中，第一水溶液的成分如表1所示：
表1第一水溶液的成分
组分 含量
三氯蔗糖-6-乙酸酯 55.2g/L
三氯蔗糖双酯 5.0g/L
四氯蔗糖-6-乙酸酯 5.3g/L
NH 4Cl 81.7g/L
其他有机杂质 33.5g/L
水 81.4％
(2)浓干步骤：将所述第一乙酯相在80℃、-0.08MPa条件下真空浓缩至干(简写为浓干)，在所得第一乙酯相浓缩物中加入水(1800mL)混合，在上述条件下浓缩至1.8L，得到三氯蔗糖-6-乙酸酯水溶液(乙酸乙酯含量为0.40g/L)，然后转移至三口烧瓶中。
(3)碱解步骤：将所得三氯蔗糖-6-乙酸酯水溶液降温至1℃，然后滴加浓度为32wt％的氢氧化钠水溶液)混合均匀，在1℃条件下碱解5h，碱解过程中保持体系的pH值为12.2，碱解结束后加热至50℃，然后滴加浓度为30wt％的稀盐酸调节pH值至7.5，过滤，得到第二水相(2L，三氯蔗糖-6-乙酸酯含量为0.04g/L)和滤渣(固废处理)。
(4)分离步骤：向所述第二水相中加入4L乙酸乙酯，在50℃条件下搅拌萃取15min，所得水相重复上述萃取操作，共萃取6次，第1～2次萃取得到的酯相合并作为第二乙酯相(8.6L)，第3～6次乙酸乙酯萃取所 得酯相依次用于下一批次三氯蔗糖粗品的制备过程中第二水相的第1～4次乙酸乙酯萃取。在所述第二乙酯相中加入1.6L水进行水洗，水洗6次，第1次水洗所得水相为第四水相，所述第四水相用于步骤(2)中代替水与所述第一乙酯相浓缩物混合；第2～6次水洗所得水相依次用于下一批次三氯蔗糖粗品的制备过程中所述第二乙酯相的第1～5次水洗，水洗结束后所得酯相为第三乙酯相。将所述第三乙酯相在70℃、-0.1MPa(表压)条件下浓干，浓干过程中加入乙酸乙酯(加入次数为3次，每次加入0.9L)进行脱水以保证水分完全去除，在所得第三乙酯相浓缩物中加入乙酸乙酯调节糖度Bx为45％，得到第四乙酯相。
(5)结晶步骤：将所述第四乙酯相在45℃条件下结晶24h，抽滤，分别得到三氯蔗糖粗品和第五乙酯相1.3L(套用4次平衡后)；将所述第五乙酯相水洗6次(每次水用量为0.6L)，水洗后的酯相为第六酯相(三氯蔗糖含量0.02g/L)，将所述第六酯相进行浓干，分别得到回收乙酸乙酯和糖渣；合并水相作为第五水相，所述第五水相用于步骤(2)中代替水与所述第一乙酯相浓缩物混合。
(6)打浆脱色：将所述三氯蔗糖粗品中加入乙酸乙酯，在室温条件下打浆10min，过滤，分别得到打浆母液和打浆目标产物，将打浆母液回用于步骤(2)中用于溶解所述第一乙酯相浓缩物；将所述打浆目标产物置于水中在45℃溶解，在得到的打浆目标产物水溶液(糖度为20％)中加入椰壳活性炭，在40℃条件下脱色10min，得到打浆脱色目标产物液；其中，三氯蔗糖粗品干重与乙酸乙酯体积之比＝1kg：1L；椰壳活性炭的质量为三氯蔗糖粗品干重质量的0.5％。
(7)第一结晶：将所述打浆脱色目标产物液在80℃、-0.08MPa(表压)条件下浓缩，将得到的打浆脱色目标产物浓缩液(糖度为40％)在室温条件下第一结晶16h，过滤，分别得到第一结晶目标产物和一次结晶母液；所述一次结晶母液用于步骤(4)中与所述第三乙酯相混合后进行共沸除水。
(8)第二结晶：将所述第一结晶目标产物置于水中，在60℃条件下溶解，将得到的第一结晶目标产物水溶液(糖度为65％)在室温条件下第二结晶8h，分别得到第二结晶目标产物和二次结晶母液；所述二次结 晶母液回用于步骤(6)中用于溶解所述打浆目标产物。
(9)第三结晶：将所述第二结晶目标产物置于水中，在50℃溶解，在得到的第二结晶目标产物水溶液(糖度为25％)中加入椰壳活性炭(活性炭质量为三氯蔗糖粗品干重的1％)，在45℃条件下脱色5min，过滤，分别得到第二结晶脱色目标产物水溶液和回收活性炭；将所述第二结晶脱色目标产物水溶液在60℃、-0.1MPa(表压)条件下进行浓缩，将得到的第二结晶脱色目标产物浓缩液(糖度为65％)在50℃条件下第三结晶4h，分别得到第三结晶目标产物和三次结晶母液；将所述第三结晶目标产物进行干燥，得到三氯蔗糖精品；所述三次结晶母液回用于步骤(3)中用于溶解所述第一结晶目标产物，所述回收活性炭回用于步骤(1)中用于对打浆目标产物水溶液进行活性炭脱色；
(10)循环利用：按照步骤(1)～(9)的操作(记为循环利用0次)，将所述第四水相、第五水相、第二乙酯相的第2～6次水洗所得水相和第二水相的第3～6次乙酸乙酯萃取所得酯相循环利用17次，其中，将步骤(2)中的“所得第一乙酯相浓缩物中加入水(1800mL)混合”修改为“将所得第一乙酯相、所述第四水相、所述第五水相和所述打浆母液混合”；将步骤(4)中的“在所得第三乙酯相浓缩物中加入乙酸乙酯调节糖度Bx为43％”替换为“在所得第三乙酯相浓缩物中加入所述一次结晶母液，在80℃、-0.08MPa(表压)条件下浓缩至水含量为0.4wt％，然后加入乙酸乙酯调节糖度Bx为43％”，所述第二水相的第1～4次乙酸乙酯萃取分别利用上一批次三氯蔗糖粗品的制备过程中第二水相的第3～6次乙酸乙酯萃取所得酯相，第二水相的第5～6次乙酸乙酯萃取利用纯乙酸乙酯进行，第二乙酯相第1～5次水洗依次利用上一批次三氯蔗糖粗品的制备过程中第二乙酯相的第2～6次水洗所得水相，第二乙酯相的第6次水洗利用纯水进行；将步骤(6)中的“将所述打浆目标产物置于水中在60℃溶解”替换为“将所述打浆目标产物置于水和所述二次结晶母液中在60℃溶解”，将步骤(6)中的椰壳活性炭替换为步骤(9)得到的回收活性炭；将步骤(8)中的“将所述第一结晶目标产物置于水中”替换为“将所述第一结晶目标产物置于水和所述三次结晶母液中”。得到的三氯蔗糖精品的纯度及收率数据如表2所示：
表2三氯蔗糖精品纯度及收率
Figure PCTCN2022126183-appb-000001
注：收率＝三氯蔗糖的质量/三氯蔗糖-6-乙酸酯完全转化成三氯蔗糖的质量×100％。第一水溶液中，三氯蔗糖双酯和四氯蔗糖-6-乙酸酯碱解后均可转化为三氯蔗糖，实施例1中理论最大收率为117.48％。
由表2可知，各母液需要循环利用至少4次方能实现三氯蔗糖精品的收率的稳定，循环17次后收率仍然在116％以上。
实施例2
按照实施例1的方法制备三氯蔗糖精品，与实施例1的区别在于：
(1)萃取步骤：在3L第一水溶液中加入1.2L乙酸乙酯，在45℃条件下搅拌萃取10min，分相，得到有机相和水相，将所述水相重复上述萃 取步骤6次，萃取完成后，酯相合并作为第一乙酯相，最后一次萃取所得水相为第一水相(三氯蔗糖-6-乙酸酯含量为0.05g/L，第一水相进行高盐废水处理)，使用的第一溶液的主要成分如表3所示：
表3第一溶液成分表
组分 含量
三氯蔗糖-6-乙酸酯 51.4g/L
三氯蔗糖双酯 5.7g/L
四氯蔗糖-6-乙酸酯 4.8g/L
NH4Cl 84.6g/L
其他有机杂质 35.1g/L
水 82.7％
(2)浓干步骤：将所述第一乙酯相在80℃、-0.08MPa条件下真空浓缩至干(简写为浓干)，在所得第一乙酯相浓缩物中加入水(1800mL)混合，在上述条件下浓缩至1.7L，得到三氯蔗糖-6-乙酸酯水溶液(乙酸乙酯含量为0.26g/L)，然后转移至三口烧瓶中。
(3)碱解步骤：将所得三氯蔗糖-6-乙酸酯水溶液降温至2℃，然后滴加浓度为32wt％的氢氧化钠水溶液)混合均匀，在2℃条件下碱解5h，碱解过程中保持体系的pH值为12.1，碱解结束后加热至50℃，然后滴加浓度为30wt％的稀盐酸调节pH值至7，过滤，得到第二水相(1.90L，三氯蔗糖-6-乙酸酯含量为0.01g/L)和滤渣(固废处理)。
(4)分离步骤：向所述第二水相中加入4L乙酸乙酯，在45℃条件下搅拌萃取10min，所得水相重复上述萃取操作，共萃取6次，第1～2次萃取得到的酯相合并作为第二乙酯相(8.5L)，第3～6次萃取所得酯相依次用于下一批次三氯蔗糖粗品的制备过程中第二水相的第1～4次乙酸乙酯萃取。在所述第二乙酯相中加入1.8L水进行水洗，水洗6次，第1次水洗所得水相为第四水相，所述第四水相用于步骤(2)中代替水与所述第一乙酯相浓缩物混合；第2～6次水洗所得水相依次用于下一批次三氯蔗糖粗品的制备过程中所述第二乙酯相的第1～5次水洗，水洗结束后所得酯相为第三乙酯相。将所述第三乙酯相在75℃、-0.1MPa(表压)条件下浓干，浓干过程中加入乙酸乙酯(加入次数为3次，每次加入0.8L) 进行脱水以保证水分完全去除，在所得第三乙酯相浓缩物中加入乙酸乙酯调节糖度Bx为44％，得到第四乙酯相。
(5)结晶步骤：将所述第四乙酯相在40℃条件下结晶20h，抽滤，分别得到三氯蔗糖粗品和第五乙酯相1.3L(套用4次平衡后)；将所述第五乙酯相水洗6次(每次水用量为0.55L)，水洗后的酯相为第六酯相(三氯蔗糖含量0.06g/L)，将所述第六酯相进行浓干，分别得到回收乙酸乙酯和糖渣；合并水相作为第五水相，所述第五水相用于步骤(2)中代替水与所述第一乙酯相浓缩物混合。
步骤(6)中，三氯蔗糖粗品干重与乙酸乙酯的体积之比＝1kg：1.5L，打浆目标产物水溶液的糖度为30％。
步骤(7)中，在60℃、-0.1MPa(表压)条件下浓缩，打浆脱色目标产物浓缩液的糖度为50％，第一结晶时间为16h。
步骤(8)中，溶解的温度为50℃，第一结晶目标产物水溶液的糖度为55％，第二结晶时间为12h。
步骤(9)中，溶解的温度为40℃，第二结晶目标产物水溶液的糖度为20％，活性炭质量为三氯蔗糖粗品干重的0.5％，脱色时间为10min，在70℃、-0.09MPa(表压)条件下进行浓缩，第二结晶脱色目标产物浓缩液的糖度为40％，在30℃条件下第三结晶12h，在50℃条件下干燥8h。
步骤(10)中，循环利用17次得到的三氯蔗糖精品的纯度及收率数据如表4所示：
表4三氯蔗糖精品纯度及收率
Figure PCTCN2022126183-appb-000002
Figure PCTCN2022126183-appb-000003
注：理论收率119.08％。
实施例3
按照实施例1的方法制备三氯蔗糖精品，与实施例1的区别在于：
(1)萃取步骤：在3L第一水溶液中加入0.85L乙酸乙酯，在50℃条件下搅拌萃取10min，分相，得到有机相和水相，将所述水相重复上述萃取步骤6次，萃取完成后，酯相合并作为第一乙酯相，最后一次萃取所得水相为第一水相(三氯蔗糖-6-乙酸酯含量为0.06g/L，第一水相进行高盐废水处理)，其中，第一溶液的主要成分如表5所示：
表5第一溶液成分表
组分 含量
三氯蔗糖-6-乙酸酯 60.1g/L
三氯蔗糖双酯 4.8g/L
四氯蔗糖-6-乙酸酯 4.7g/L
NH 4Cl 80.3g/L
其他有机杂质 30.4g/L
水 82.7％
(2)浓干步骤：将所述第一乙酯相在80℃、-0.08MPa条件下真空浓缩至干(简写为浓干)，在所得第一乙酯相浓缩物中加入水(1800mL)混合，在上述条件下浓缩至1.8L，得到三氯蔗糖-6-乙酸酯水溶液(乙酸 乙酯含量为0.41g/L)，然后转移至三口烧瓶中。
(3)碱解步骤：将所得三氯蔗糖-6-乙酸酯水溶液降温至3℃，然后滴加浓度为32wt％的氢氧化钠水溶液)混合均匀，在3℃条件下碱解6h，碱解过程中保持体系的pH值为12.5，碱解结束后加热至45℃，然后滴加浓度为30wt％的稀盐酸调节pH值至7，过滤，得到第二水相(2L，三氯蔗糖-6-乙酸酯含量为0.05g/L)和滤渣(固废处理)。
(4)分离步骤：向所述第二水相中加入4.1L乙酸乙酯，在50℃条件下搅拌萃取10min，所得水相重复上述萃取操作，共萃取6次，第1～2次萃取得到的酯相合并作为第二乙酯相(8.5L)，第3～6次乙酸乙酯萃取所得酯相依次用于下一批次三氯蔗糖粗品的制备过程中第二水相的第1～4次乙酸乙酯萃取。在所述第二乙酯相中加入1.7L水进行水洗，水洗6次，第1次水洗所得水相为第四水相，所述第四水相用于步骤(2)中代替水与所述第一乙酯相浓缩物混合；第2～6次水洗所得水相依次用于下一批次三氯蔗糖粗品的制备过程中所述第二乙酯相的第1～5次水洗，水洗结束后所得酯相为第三乙酯相。将所述第三乙酯相在80℃、-0.09MPa(表压)条件下浓干，浓干过程中加入乙酸乙酯(加入次数为3次，每次加入0.8L)进行脱水以保证水分完全去除，在所得第三乙酯相浓缩物中加入乙酸乙酯调节糖度Bx为41％，得到第四乙酯相。
(5)结晶步骤：将所述第四乙酯相在40℃条件下结晶18h，抽滤，分别得到三氯蔗糖粗品和第五乙酯相1.1L(套用4次平衡后)；将所述第五乙酯相水洗6次(每次水用量为0.55L)，水洗后的酯相为第六酯相(三氯蔗糖含量0.07g/L)，将所述第六酯相进行浓干，分别得到回收乙酸乙酯和糖渣；合并水相作为第五水相，所述第五水相用于步骤(2)中代替水与所述第一乙酯相浓缩物混合。
步骤(6)中，三氯蔗糖粗品干重与乙酸乙酯的体积之比＝1kg：1.2L，打浆目标产物水溶液的糖度为25％。
步骤(7)中，在70℃、-0.09MPa(表压)条件下浓缩，打浆脱色目标产物浓缩液的糖度为65％，第一结晶时间为8h。
步骤(8)中，溶解的温度为40℃，第一结晶目标产物水溶液的糖度为40％，第二结晶时间为16h。
步骤(9)中，溶解的温度为60℃，第二结晶目标产物水溶液的糖度为30％，活性炭质量为三氯蔗糖粗品干重的0.7％，脱色时间为8min，在80℃、-0.08MPa(表压)条件下进行浓缩，第二结晶脱色目标产物浓缩液的糖度为55％，在40℃条件下第三结晶8h，在45℃条件下干燥10h。
步骤(10)中，循环利用17次得到的三氯蔗糖精品的纯度及收率数据如表6所示：
表6三氯蔗糖精品纯度及收率
Figure PCTCN2022126183-appb-000004
注：理论收率114.79％。
母液循环套用是提高目标产品收率，降低生产成本的重要手段之一。套用成功的关键是如何将反复循环套用过程中富集的杂质与目标产品分 离，只有持续不断的将杂质与目标产品分离，并排出工艺系统，才能保证工艺的稳定运行。因此，在哪步工段，以何种方式将杂质分离并排出是该工艺的重点。本发明通过对三氯蔗糖粗品进行乙酸乙酯打浆处理，两次不同阶段活性炭除杂，以及第三结晶，可以有效将粗品中的杂质以及结晶母液套用过程中因氧化产生的杂质去除，排出系统。
而且。本发明研究发现若将三氯蔗糖粗品提纯过程中产生的所有母液全部进行循环利用，会导致杂质的富集，从而无法获得合格的三氯蔗糖精品，且套用多次后会出现无法结晶的现象。而本发明根据各制备步骤过程中产生的母液的不同特性(如溶剂，杂质含量)，将部分母液(打浆母液和一次结晶母液)用于制备三氯蔗糖粗品，部分母液(二次结晶母液和三次结晶母液)回用于三氯蔗糖粗品的提纯，从而实现了母液的循环套用，且套用多次后也未发现无法结晶的现象，显著提高三氯蔗糖的收率，降低三氯蔗糖在提纯过程中的损耗。
综上所述，将本发明的三氯蔗糖精品的制备方法能够与利用水解体系制备三氯蔗糖粗品的方法进行有效结合，可以实现三氯蔗糖精品在制作过程中形成的母液循环套用，解决了母液资源浪费的问题，减少废液的量，最大限度的回收三氯蔗糖，显著增加了三氯蔗糖的收率，还能够制备成不同形态的食品级三氯蔗糖精品，显著降低了生产成本，具有较高的工业化前景。
以上实施例的说明只是用于帮助理解本发明的方法及其核心思想。应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明原理的前提下，还可以对本发明进行若干改进和修饰，这些改进和修饰也落入本发明权利要求的保护范围内。对这些实施例的多种修改对本领域的专业技术人员来说是显而易见的，本文中所定义的一般原理可以在不脱离本发明的精神或范围的情况下在其它实施例中实现。因此，本发明将不会被限制于本文所示的这些实施例，而是要符合与本文所公开的原理和新颖特点相一致的最宽的范围。

Claims (24)

  1. 一种三氯蔗糖精品的制备方法，其特征在于，包括以下步骤：
    (1)将三氯蔗糖粗品与乙酸乙酯混合，进行打浆后固液分离，分别得到打浆母液和打浆目标产物；将所述打浆目标产物溶解于水中，将得到的打浆目标产物水溶液进行活性炭脱色，得到打浆脱色目标产物液；
    (2)将所述打浆脱色目标产物液进行浓缩，将得到的打浆脱色目标产物浓缩液进行第一结晶，分别得到第一结晶目标产物和一次结晶母液；
    (3)将所述第一结晶目标产物溶解于水中，将得到的第一结晶目标产物水溶液进行第二结晶，分别得到第二结晶目标产物和二次结晶母液；所述二次结晶母液回用于步骤(1)中用于溶解所述打浆目标产物；
    (4)将所述第二结晶目标产物溶解于水中，将得到的第二结晶目标产物水溶液进行活性炭脱色后固液分离，分别得到第二结晶脱色目标产物水溶液和回收活性炭；将所述第二结晶脱色目标产物水溶液进行浓缩，将得到的第二结晶脱色目标产物浓缩液进行第三结晶，分别得到第三结晶目标产物和三次结晶母液；将所述第三结晶目标产物进行干燥，得到三氯蔗糖精品；所述三次结晶母液回用于步骤(3)中用于溶解所述第一结晶目标产物，所述回收活性炭回用于步骤(1)中用于对打浆目标产物水溶液进行活性炭脱色。
  2. 根据权利要求1所述的制备方法，其特征在于，步骤(1)中，所述三氯蔗糖粗品包括以下质量百分含量的组分：三氯蔗糖85～95％，三氯蔗糖-6-乙酸酯0.5～1％，乙酸乙酯1～3％，焦糖类杂质1～13.5％。
  3. 根据权利要求1或2所述的制备方法，其特征在于，步骤(1)中，所述三氯蔗糖粗品的质量与乙酸乙酯的体积之比为1kg：1～1.5L。
  4. 根据权利要求1所述的制备方法，其特征在于，步骤(1)中，所述溶解的温度为30～50℃；
    所述打浆目标产物水溶液的糖度为20～40％。
  5. 根据权利要求1所述的制备方法，其特征在于，步骤(2)中，所述打浆脱色目标产物浓缩液的糖度为40～65％。
  6. 根据权利要求1或5所述的制备方法，其特征在于，步骤(2)中，所述第一结晶的温度为室温，时间为8～16h。
  7. 根据权利要求1所述的制备方法，其特征在于，步骤(3)中，所述溶解的温度为40～60℃；
    所述第一结晶目标产物水溶液的糖度为40～65％。
  8. 根据权利要求1或7所述的制备方法，其特征在于，步骤(3)中，所述第二结晶的温度为室温，时间为8～16h。
  9. 根据权利要求1所述的制备方法，其特征在于，步骤(4)中，所述溶解的温度为40～60℃；
    所述第二结晶脱色目标产物水溶液的糖度为20～30％。
  10. 根据权利要求1所述的制备方法，其特征在于，步骤(4)中，所述第二结晶脱色目标产物浓缩液的糖度为40～65％。
  11. 根据权利要求1或10所述的制备方法，其特征在于，步骤(4)中，所述第三结晶的温度为30～50℃，时间为4～12h。
  12. 根据权利要求1所述的制备方法，其特征在于，所述三氯蔗糖粗品的制备方法包括以下步骤：
    (a)将原料液进行乙酸乙酯萃取，分别得到第一乙酯相和第一水相；将所述第一乙酯相进行浓缩，得到第一乙酯相浓缩物；所述原料液为包括三氯蔗糖-6-乙酸酯、三氯蔗糖双酯和四氯蔗糖-6-乙酸酯的水溶液；
    (b)将所述第一乙酯相浓缩物与水混合溶解，进行浓缩，得到三氯蔗糖-6-乙酸酯水溶液；
    (c)将所述三氯蔗糖-6-乙酸酯水溶液与碱金属氢氧化物混合，进行碱解反应，将得到的反应液进行中和后过滤，得到第二水相；
    (d)将所述第二水相进行乙酸乙酯萃取，分别得到第二乙酯相和第三水相；
    (e)将所述第二乙酯相进行水洗，分别得到第四水相和第三乙酯相；所述第四水相回用于步骤(b)中用于溶解所述第一乙酯相浓缩物；
    (f)将所述第三乙酯相与乙酸乙酯混合，进行共沸除水，得到第三乙酯相浓缩物；将所述第三乙酯相浓缩物与乙酸乙酯混合，得到第四乙酯相；
    (g)将所述第四乙酯相进行结晶，分别得到三氯蔗糖粗品和第五乙酯相；
    (h)将所述第五乙酯相进行水洗，分别得到第五水相和第六乙酯相；所述第五水相回用于步骤(b)用于溶解所述第一乙酯相浓缩物。
  13. 根据权利要求1或12所述的制备方法，其特征在于，所述打浆母液和一次结晶母液回用于制备三氯蔗糖粗品。
  14. 根据权利要求13所述的制备方法，其特征在于，所述回用时，打浆母液用于溶解所述第一乙酯相浓缩物，一次结晶母液与所述第三乙酯相混合后共沸除水。
  15. 根据权利要求12所述的方法，其特征在于，所述第三水相、第四水相和第五水相中三氯蔗糖含量独立地<0.5g/L。
  16. 根据权利要求12所述的方法，其特征在于，步骤(a)中，所述乙酸乙酯萃取的温度为40～60℃，萃取次数为5～8次；所述原料液与单次乙酸乙酯萃取用乙酸乙酯的体积比为1：0.2～0.5。
  17. 根据权利要求12所述的方法，其特征在于，步骤(b)中，所述三氯蔗糖-6-乙酸酯水溶液中乙酸乙酯的含量＜0.5g/L。
  18. 根据权利要求12所述的方法，其特征在于，步骤(c)中，所述碱解反应的pH值为11～13，温度为0～10℃，时间3～6h。
  19. 根据权利要求12所述的方法，其特征在于，步骤(c)中，所述中和与过滤的温度独立地为50～70℃。
  20. 根据权利要求12所述的方法，其特征在于，步骤(d)中，所述乙酸乙酯萃取的次数为4～7次；所述第二水相与乙酸乙酯萃取单次用乙酸乙酯的体积比为1：1～3；
    将第1～2次乙酸乙酯萃取得到的乙酯相合并作为第二乙酯相；
    将第3～7次乙酸乙酯萃取得到的乙酯相用于下一批次三氯蔗糖粗品制备过程中所述第二水相的乙酸乙酯萃取。
  21. 根据权利要求12所述的方法，其特征在于，步骤(e)中，所述水洗的次数为3～6次；所述第二乙酯相与水洗的单次用水的体积比为1：0.1～0.3；
    将第1次水洗得到的水相作为第四水相；
    将第2～6次水洗得到的水相用于下一批次三氯蔗糖粗品制备过程中所述第二乙酯相的水洗。
  22. 根据权利要求12所述的方法，其特征在于，步骤(f)中，所述第三乙酯相浓缩液的水含量＜0.5wt％。
  23. 根据权利要求12所述的方法，其特征在于，步骤(f)中，所述第四乙酯相的糖度为40～60％。
  24. 根据权利要求12或23所述的方法，其特征在于，步骤(g)中，所述结晶的温度为40～60℃，时间12～30h。
PCT/CN2022/126183 2022-10-19 2022-10-19 一种三氯蔗糖精品的制备方法 WO2024082175A1 (zh)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103087116A (zh) * 2011-11-07 2013-05-08 常茂生物化学工程股份有限公司 三氯蔗糖的制备方法
CN106674293A (zh) * 2016-12-09 2017-05-17 福建科宏生物工程股份有限公司 一种利用水解方式处理三氯蔗糖‑6‑乙酸酯废弃母液的方法
CN112585151A (zh) * 2020-11-13 2021-03-30 安徽金禾实业股份有限公司 三氯蔗糖的提纯方法
CN114014897A (zh) * 2021-12-20 2022-02-08 安徽金禾实业股份有限公司 一种三氯蔗糖的纯化结晶方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103087116A (zh) * 2011-11-07 2013-05-08 常茂生物化学工程股份有限公司 三氯蔗糖的制备方法
CN106674293A (zh) * 2016-12-09 2017-05-17 福建科宏生物工程股份有限公司 一种利用水解方式处理三氯蔗糖‑6‑乙酸酯废弃母液的方法
CN112585151A (zh) * 2020-11-13 2021-03-30 安徽金禾实业股份有限公司 三氯蔗糖的提纯方法
CN114014897A (zh) * 2021-12-20 2022-02-08 安徽金禾实业股份有限公司 一种三氯蔗糖的纯化结晶方法

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