阅读说明：本技术 一种从三氯蔗糖废水中提纯二氯蔗糖-6-乙酯制备三氯蔗糖的方法 (Method for preparing sucralose by purifying dichlorosucrose-6-ethyl ester from sucralose wastewater ) 是由 杨志健 赵金刚 许传久 于 2021-08-17 设计创作，主要内容包括：本发明涉及一种从三氯蔗糖废水中提纯二氯蔗糖-6-乙酯制备三氯蔗糖的方法,其特征在于：(1)氯化中和后废水与溶剂按体积比1:0.5～1打入混合器,25～35℃下循环1～2h,有机相去蒸馏釜进行蒸馏；(2)控制蒸馏釜温度在80～100℃,负压-0.09～-0.10MPa；(3)精馏结束,向蒸馏釜中加DMF溶剂,控制釜内二氯蔗糖-6-乙酯浓度在250～300g/L,将物料放入定容液槽；(4)向反应釜中加三氯乙烷溶液、氯化亚砜,控制温度-5～-10℃,再加定溶液槽中物料,滴加温度在-5～0℃；(5)滴加结束搅拌1～1.5h,随后匀速升温到80～90℃,保温0.5～1h,反应液并入产线进行浓干精制。本发明优点：提取了废水中的二氯蔗糖-6-乙酯,可反应生成三氯蔗糖中间产物,加工成产品；降低了废水中有机物的浓度,减少废水的同时降低了废水的处理难度。(The invention relates to a method for preparing sucralose by purifying dichlorosucrose-6-ethyl ester from sucralose wastewater, which is characterized by comprising the following steps: (1) adding the waste water and the solvent after chlorination neutralization into a mixer according to the volume ratio of 1: 0.5-1, circulating for 1-2 h at the temperature of 25-35 ℃, and distilling the organic phase in a distillation kettle; (2) controlling the temperature of the distillation kettle at 80-100 ℃ and negative pressure of-0.09 to-0.10 MPa; (3) after rectification, adding a DMF solvent into a distillation kettle, controlling the concentration of the dichlorosucrose-6-ethyl ester in the kettle to be 250-300 g/L, and putting the material into a constant volume liquid tank; (4) adding trichloroethane solution and thionyl chloride into a reaction kettle, controlling the temperature to be minus 5 to minus 10 ℃, then adding materials in a solution tank, and dropwise adding the materials at the temperature of minus 5 to 0 ℃; (5) and after the dropwise addition is finished, stirring for 1-1.5 h, then uniformly heating to 80-90 ℃, preserving heat for 0.5-1 h, and merging the reaction liquid into a production line for concentrated drying and refining. The invention has the advantages that: the dichloro sucrose-6-ethyl ester in the wastewater is extracted, and can react to generate a trichlorosucrose intermediate product which is processed into a product; the concentration of organic matters in the wastewater is reduced, and the wastewater treatment difficulty is reduced while the wastewater is reduced.)

1. A method for preparing sucralose by purifying dichlorosucrose-6-ethyl ester from sucralose wastewater is characterized by comprising the following steps:

(1) pumping the chlorinated and neutralized wastewater in sucralose and a solvent into a mixer according to the volume ratio of 1: 0.5-1, controlling the temperature of the mixer to be 25-35 ℃, forcibly circulating for 1-2 hours, separating out a water phase and removing wastewater, and removing an organic phase in a distillation kettle for reduced pressure distillation;

(2) controlling the temperature of the distillation kettle at 80-100 ℃, and returning the recovered solvent to the mixer for reuse under negative pressure of-0.09 to-0.10 MPa;

(3) after the vacuum rectification is finished, adding a DMF solvent into a distillation kettle, controlling the concentration of the dichlorosucrose-6-ethyl ester in the distillation kettle to be 250-300 g/L, and then putting the materials in the distillation kettle into a constant volume liquid tank;

(4) adding a trichloroethane solution into a reaction kettle, controlling the temperature of the reaction kettle to be within-5 to-10 ℃, then dropwise adding thionyl chloride, keeping the temperature to be within-5 to-10 ℃, finally dropwise adding a mixed solution of dichlorosucrose-6-ethyl ester and DMF (dimethyl formamide) in a solution tank into the reaction kettle, and keeping the temperature of the reaction kettle within-5 to 0 ℃ in the dropwise adding process; wherein the volume of the trichloroethane solution is controlled to be 0.8-1.5 times of that of DMF, and the mass of the thionyl chloride is controlled to be 1.5-2.5 times of that of the dichlorosucrose-6-ethyl ester;

(5) stirring for 1-1.5 hours after the dropwise adding is finished, then carrying out heating reaction, raising the temperature of the reaction kettle to 80-90 ℃ at a constant speed, preserving the temperature for 0.5-1 hour, sampling and detecting after the reaction is finished, and merging the reaction liquid into a production line for concentration, drying and refining.

2. The method for preparing sucralose by purifying dichlorosucrose-6-ethyl ester from sucralose waste water according to claim 1, wherein: the solvent in the step (1) is n-butanol, n-pentanol or isobutanol.

3. The method for preparing sucralose by purifying dichlorosucrose-6-ethyl ester from sucralose waste water according to claim 1 or 2, wherein: and (5) heating the reaction kettle to 85-90 ℃.

Technical Field

The invention belongs to the technical field of sucralose production, relates to a method for treating sucralose chlorination tail gas, and particularly relates to a method for preparing sucralose by purifying sucralose-6-ethyl ester from sucralose wastewater.

Background

Sucralose (TGS), a novel sweetener developed by the british tare company (Tate & ly) and university of london and patented in 1976, is a functional sweetener exclusively using sucrose as a raw material, and has an original trade name of spleena, and the sweetness can reach 600 times that of sucrose; the sweetener has the characteristics of no energy, high sweetness, pure sweetness, high safety and the like, and is one of the most excellent functional sweeteners at present.

At present, the domestic sucralose production process is a three-step process for producing sucralose by starting from sucrose, generating sucrose-6-ethyl ester by using organotin ester, adding thionyl chloride to generate sucralose-6-ethyl ester, and finally carrying out alcoholysis. In the chlorination process, seven hydroxyl positions in the sucrose-6-ethyl ester are sequentially substituted by chlorine atoms, so that part of the sucrose-6-ethyl ester is generated into dichloro sucrose-6-ethyl ester, and the dichloro sucrose-6-ethyl ester is dissolved in wastewater (about 10-15 g/L); the direct discharge of the wastewater not only increases the difficulty of wastewater treatment, but also causes the waste of raw materials.

Disclosure of Invention

The invention aims to solve the problems of extraction and utilization of dichlorosucrose-6-ethyl ester in wastewater, and provides a method for preparing sucralose by purifying dichlorosucrose-6-ethyl ester from sucralose wastewater; the invention firstly extracts the dichloro sucrose-6-ethyl ester by the extractant, and then reacts to generate the trichlorosucrose, thereby effectively recycling the dichloro sucrose-6-ethyl ester.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a method for preparing sucralose by purifying dichlorosucrose-6-ethyl ester from sucralose wastewater is characterized in that

The method comprises the following steps:

(1) pumping the chlorinated and neutralized wastewater in sucralose and a solvent (n-butyl alcohol, n-amyl alcohol or isobutyl alcohol) into a mixer according to the volume ratio of 1: 0.5-1, controlling the temperature of the mixer to be 25-35 ℃, forcibly circulating for 1-2 hours, separating out a water phase to remove the wastewater, and feeding an organic phase into a distillation kettle for reduced pressure distillation;

(2) controlling the temperature of the distillation kettle at 80-100 ℃, and returning the recovered solvent to the mixer for reuse under negative pressure of-0.09 to-0.10 MPa;

(3) after the vacuum rectification is finished, adding a DMF solvent into a distillation kettle, controlling the concentration of the dichlorosucrose-6-ethyl ester in the distillation kettle to be 250-300 g/L, and then putting the materials in the distillation kettle into a constant volume liquid tank;

(4) adding a trichloroethane solution into a reaction kettle, controlling the temperature of the reaction kettle to be within-5 to-10 ℃, then dropwise adding thionyl chloride, keeping the temperature to be within-5 to-10 ℃, finally dropwise adding a mixed solution of dichlorosucrose-6-ethyl ester and DMF (dimethyl formamide) in a solution tank into the reaction kettle, and keeping the temperature of the reaction kettle within-5 to 0 ℃ in the dropwise adding process; wherein the volume of the trichloroethane solution is controlled to be 0.8-1.5 times of that of DMF, and the mass of the thionyl chloride is controlled to be 1.5-2.5 times of that of the dichlorosucrose-6-ethyl ester;

(5) stirring for 1-1.5 hours after the dropwise adding is finished, then carrying out heating reaction, raising the temperature of the reaction kettle to 80-90 ℃ at a constant speed, preserving the temperature for 0.5-1 hour, sampling and detecting after the reaction is finished, and merging the reaction liquid into a production line for concentration, drying and refining.

Further, in the step (5), the temperature of the reaction kettle is increased to 85-90 ℃.

The chlorination reaction temperature of the sucrose-6-ethyl ester is 110-115 ℃, and the dichloro sucrose-6-ethyl ester is different from the chlorination reaction of the sucrose-6-ethyl ester because two chlorine atoms exist in the dichloro sucrose-6-ethyl ester; if the reaction is carried out according to the chlorination reaction temperature of the sucrose-6-ethyl ester, a large amount of raw materials of the dichloro sucrose-6-ethyl ester can be carbonized to cause excessive reaction, so that the chlorination temperature of the dichloro sucrose-6-ethyl ester is determined to be 80-90 ℃.

The invention has the beneficial effects that:

1. the dichloro sucrose-6-ethyl ester in the wastewater is effectively extracted through extraction, the concentration of organic matters in the wastewater is reduced (from 10-15g/L to below 5 g/L), the wastewater is reduced, the difficulty in treating the wastewater is reduced, the cost is saved, and the environment is protected;

2. the extracted dichloro-sucrose-6-ethyl ester reacts to generate a sucralose intermediate product (the content of the sucralose-6-ethyl ester is 80-85 percent), and the sucralose intermediate product can be continuously processed into a product, so that the yield is improved.

Description of the drawings

FIG. 1 is a schematic diagram of a process for purifying dichlorosucrose-6-ethyl ester from sucralose waste water to prepare sucralose.

Detailed Description

Referring to fig. 1, the present invention is further illustrated, a method for preparing sucralose by purifying dichlorosucrose-6-ethyl ester from sucralose wastewater, which comprises the following specific steps:

example 1

(1) Carrying out 30m high-speed drytesting on the waste water (12 g/L of dichlorosucrose-6-ethyl ester) after chlorination neutralization in sucralose and 15 m high-speed butanol according to the flow ratio of 1:0.5, driving the waste water and the n-butanol into an extraction mixer, controlling the temperature of the mixer to be 30 ℃, forcibly circulating for 1.5 hours, separating out a water phase, conveying the water phase to a waste water treatment system, and conveying an organic phase (n-butanol phase) to a distillation still for reduced pressure distillation;

(2) controlling the temperature of the distillation kettle at 81 ℃ and the negative pressure of-0.095 MPa, and returning the recovered solvent to the mixer for reuse;

(3) after the vacuum rectification is finished, adding 800L of DMF solvent into a distillation kettle, wherein the concentration of the dichlorosucrose-6-ethyl ester in the distillation kettle is 262g/L, and then putting the material (1050L) in the distillation kettle into a constant volume liquid tank;

(4) adding 1000L of trichloroethane solution into a reaction kettle, controlling the temperature of the reaction kettle to be-8 ℃, dropwise adding 400L of thionyl chloride into the reaction kettle, and keeping the temperature to be-8 ℃; adding a mixed solution 1050L of dichlorosucrose-6-ethyl ester and DMF in a solution tank into a reaction kettle through a metering tank, and keeping the temperature of the reaction kettle at-2 ℃ in the dropwise adding process;

(5) stirring for 1 hour after the dropwise adding is finished, then carrying out heating reaction, raising the temperature of the reaction kettle to 85 ℃ at a constant speed, keeping the temperature for 40min, sampling and detecting after the reaction is finished, and obtaining that the concentration of the sucralose-6-ethyl ester is 59g/L (the yield is 75%), and adding the reaction liquid into a production line for concentrated drying and refining to obtain 170Kg (the yield is 85%) of sucralose.

Example 2

(1) Carrying out double-cropping labor on the wastewater (10 g/L of dichlorosucrose-6-ethyl ester) after chlorination neutralization in sucralose at 40m and the n-amyl alcohol at 20m according to the flow ratio of 1:0.5, driving the wastewater into an extraction mixer, controlling the temperature of the mixer to be 35 ℃, carrying out forced circulation for 1 hour, separating out a water phase, conveying the water phase to a wastewater treatment system, and conveying an organic phase (the n-amyl alcohol phase) to a distillation still for reduced pressure distillation;

(2) controlling the temperature of the distillation kettle at 85 ℃ and the negative pressure of-0.09 MPa, and returning the recovered solvent to the mixer for reuse;

(3) after the reduced pressure rectification is finished, 1000L of DMF solvent is added into a distillation kettle, the concentration of the dichlorosucrose-6-ethyl ester in the distillation kettle is 255g/L, and then the material (1200L) in the distillation kettle is put into a constant volume liquid tank;

(4) adding 1500L of trichloroethane solution into a reaction kettle, controlling the temperature of the reaction kettle to be-10 ℃, dropwise adding 500L of thionyl chloride into the reaction kettle, and keeping the temperature to be-10 ℃; adding 1200L of mixed solution of dichlorosucrose-6-ethyl ester and DMF in a solution tank into a reaction kettle through a metering tank, and keeping the temperature of the reaction kettle at-1 ℃ in the dropwise adding process;

(5) stirring for 1.2 hours after the dropwise addition is finished, then carrying out heating reaction, raising the temperature of the reaction kettle to 90 ℃ at a constant speed, keeping the temperature for 30min, sampling and detecting after the reaction is finished, and obtaining that the concentration of the sucralose-6-ethyl ester is 55g/L (the yield is 73%), and adding the reaction liquid into a production line for concentrated drying and refining to obtain 165Kg (the yield is 83%) of sucralose.

Example 3

(1) Carrying out dry top milling on 40m of chlorinated and neutralized wastewater (sucralose-6-ethyl ester 15 g/L) in sucralose and isobutanol 20m according to a flow ratio of 1:0.5, driving the dry top milling and the isobutanol 20m into an extraction mixer, controlling the temperature of the mixer to be 25 ℃, forcibly circulating for 2 hours, separating out a water phase, removing the water phase to a wastewater treatment system, and removing an organic phase (isobutanol phase) into a distillation still for reduced pressure distillation;

(2) controlling the temperature of the distillation kettle at 90 ℃ and the negative pressure of-0.1 MPa, and returning the recovered solvent to the mixer for reuse;

(3) after the reduced pressure rectification is finished, adding 900L of DMF solvent into a distillation kettle, wherein the concentration of the dichlorosucrose-6-ethyl ester in the distillation kettle is 258g/L, and then putting the material (1100L) in the distillation kettle into a constant volume liquid tank;

(4) adding 1200L of trichloroethane solution into a reaction kettle, controlling the temperature of the reaction kettle to be-7 ℃, dropwise adding 500L of thionyl chloride into the reaction kettle, and keeping the temperature to be-6 ℃; adding 1100L of mixed solution of dichlorosucrose-6-ethyl ester and DMF in a solution tank into a reaction kettle through a metering tank, and keeping the temperature of the reaction kettle at-5 ℃ in the dropwise adding process;

(5) stirring for 1.5 hours after the dropwise addition is finished, then carrying out heating reaction, raising the temperature of the reaction kettle to 80 ℃ at a constant speed, keeping the temperature for 55min, sampling and detecting after the reaction is finished, and obtaining that the concentration of the sucralose-6-ethyl ester is 52g/L (the yield is 77%), and adding the reaction liquid into a production line for concentrated drying and refining to obtain 380Kg of sucralose (the yield is 83%).