阅读说明：本技术 一种米黑根毛霉脂肪酶催化合成蔗糖-6-乙酸酯的方法 (Method for synthesizing sucrose-6-acetate by using rhizomucor miehei lipase as catalyst ) 是由 张正颂 祁飞 肖士东 郑学连 于 2020-05-25 设计创作，主要内容包括：本发明涉及一种米黑根毛霉脂肪酶催化合成蔗糖-6-乙酸酯的方法,其特征在于：a．DMF和叔戊醇按体积比1:3-5投入反应釜,混匀；b．将蔗糖投入反应釜,加入乙酸乙烯酯、米黑根毛霉脂肪酶,控制蔗糖浓度0.03~0.12mmoL/mL,米黑根毛霉脂肪酶浓度6~60mg/mL,蔗糖与乙酸乙烯酯摩尔比1:5~20,30-35℃反应8-24h,过滤,滤液室温放置20-40min；c．滤液进行减压精馏,温度50-70℃、压力-0.080~-0.1Mpa,冷凝槽中的液体冷却至室温,加入二氯甲烷,出现浑浊后再次加入二氯甲烷,控制二氯甲烷总量与冷凝液体积比4-7：3,静置,过滤得母液；d．母液泵入离心机,得淡黄色晶体。本发明优点：本发明反应条件温和、操作简单,避免了异构体的产生,催化选择性强,产品安全性好、转化率高和成本低。(The invention relates to a method for synthesizing sucrose-6-acetate by using rhizomucor miehei lipase catalysis, which is characterized by comprising the following steps: putting DMF and tert-amyl alcohol into a reaction kettle according to the volume ratio of 1:3-5, and uniformly mixing; b. adding sucrose into a reaction kettle, adding vinyl acetate and Rhizomucor miehei lipase, controlling the concentration of the sucrose to be 0.03-0.12 mmoL/mL, the concentration of the Rhizomucor miehei lipase to be 6-60 mg/mL, the molar ratio of the sucrose to the vinyl acetate to be 1: 5-20, reacting for 8-24h at the temperature of 30-35 ℃, filtering, and standing the filtrate for 20-40min at room temperature; c. and (3) carrying out reduced pressure rectification on the filtrate at the temperature of 50-70 ℃ and under the pressure of-0.080 to-0.1 Mpa, cooling the liquid in a condensation tank to room temperature, adding dichloromethane again after turbidity appears, and controlling the volume ratio of the total amount of the dichloromethane to the condensate to be 4-7: 3, standing and filtering to obtain mother liquor; d. pumping the mother liquid into a centrifuge to obtain light yellow crystals. The invention has the advantages that: the method has the advantages of mild reaction conditions, simple operation, strong catalytic selectivity, good product safety, high conversion rate and low cost, and avoids the generation of isomers.)

1. A method for synthesizing sucrose-6-acetate by Rhizomucor miehei lipase catalysis is characterized by comprising the following steps:

a. putting DMF and tert-amyl alcohol into a reaction kettle according to the volume ratio of 1:3-5, and uniformly mixing to obtain an organic solution mixed solution;

b. adding sucrose into a reaction kettle, stirring to completely dissolve the sucrose, then adding vinyl acetate and Mucor miehei lipase into the reaction kettle, controlling the concentration of the sucrose in a machine solution mixed solution to be 0.03-0.12 mmoL/mL, controlling the concentration of the Mucor miehei lipase to be 6-60 mg/mL, controlling the molar ratio of the sucrose to the vinyl acetate to be 1: 5-20, carrying out heat preservation reaction at 30-35 ℃ for 8-24h under the stirring condition, filtering the material after the reaction is finished to remove the Mucor miehei lipase, and standing the filtrate at room temperature for 20-40 min;

c. carrying out reduced pressure rectification on the filtrate, controlling the temperature to be 50-70 ℃ and the pressure to be-0.080 to-0.1 Mpa, collecting liquid in a condensation tank, cooling the liquid to room temperature, then adding dichloromethane, adding dichloromethane again after turbidity appears, and controlling the volume ratio of the total amount of the dichloromethane to the condensate to be 4-7: 3, standing and filtering to obtain mother liquor;

d. and pumping the mother liquor obtained after filtration into a centrifuge to obtain light yellow crystals.

2. The method for the catalytic synthesis of sucrose-6-acetate by Rhizomucor miehei lipase according to claim 1, characterized in that: the volume ratio of DMF to t-amyl alcohol in step a is preferably 1: 4.

3. The method for the catalytic synthesis of sucrose-6-acetate by Rhizomucor miehei lipase according to claim 1, characterized in that: the concentration of the sucrose in the step b is preferably 0.05-0.08 mmoL/mL.

4. The method for the catalytic synthesis of sucrose-6-acetate by Rhizomucor miehei lipase according to claim 1, characterized in that: and c, in the step b, the concentration of the rhizomucor miehei lipase is 25-40 mg/mL.

5. The method for the catalytic synthesis of sucrose-6-acetate by Rhizomucor miehei lipase according to any of claims 1-4, characterized in that: the molar ratio of the sucrose to the vinyl acetate in the step b is preferably 1: 8-13.

Technical Field

The invention belongs to the technical field of chemical production, relates to the field of sucralose production, and particularly relates to a method for synthesizing sucrose-6-acetate by using Mucor miehei lipase as a catalyst.

Background

Sucralose is a fresh sweetener, which is a novel sweetener developed by the company of England and university of London and applied for patent in 1976, and is the only functional sweetener using sucrose as raw material. The sucralose has the effect of desalting sour and salty tastes, has the effect of covering up unpleasant tastes such as astringent taste, bitter taste, alcoholic taste and the like, has the synergistic effect on spicy taste and milk taste, and has a very wide application range. Therefore, the product is the most ideal intense sweetener at present, can be eaten by children, teenagers, adolescents, middle-aged people, old people and patients with various diseases, and has no any nutritional doubt. The method for synthesizing sucrose-6-acetate is mainly a traditional chemical method, such as acetic anhydride esterification method, organic metal synthesis method, orthoester method, etc. The chemical synthesis reaction conditions for synthesizing sucrose-6-acetate are generally harsh, the synthesized product has dark color, and by-products are easily generated due to poor selectivity.

Disclosure of Invention

The invention aims to solve the problems of harsh reaction conditions, poor selectivity, a large number of byproducts and deep product color in the existing chemical synthesis process of sucrose-6-acetate, and provides a method for synthesizing sucrose-6-acetate by using Mucor miehei lipase through catalysis.

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

a method for synthesizing sucrose-6-acetate by Rhizomucor miehei lipase catalysis is characterized by comprising the following steps:

a. putting DMF and tert-amyl alcohol into a reaction kettle according to the volume ratio of 1:3-5, and uniformly mixing to obtain an organic solution mixed solution;

b. putting sucrose into a reaction kettle, stirring to completely dissolve the sucrose, then adding vinyl acetate and Mucor miehei lipase into the reaction kettle, controlling the concentration of the sucrose in a machine solution mixed solution to be 0.03-0.12 mmoL/mL, controlling the concentration of the Mucor miehei lipase to be 6-60 mg/mL, controlling the molar ratio of the sucrose to the vinyl acetate to be 1: 5-20, carrying out heat preservation reaction at 30-35 ℃ for 8-24h under the stirring condition (100 plus 300 rpm), filtering the material after the reaction is finished to remove the Mucor miehei lipase, and placing the filtrate for 20-40min at room temperature;

c. carrying out reduced pressure rectification on the filtrate, controlling the temperature to be 50-70 ℃ and the pressure to be-0.080 to-0.1 Mpa, collecting liquid in a condensation tank, cooling the liquid to room temperature, then adding dichloromethane, adding dichloromethane again after turbidity appears, ensuring that the dichloromethane is excessive, and controlling the volume ratio of the total amount of the dichloromethane to the condensate to be 4-7: 3, standing and filtering to obtain mother liquor;

d. pumping the obtained mother liquor after filtration into a centrifuge to obtain light yellow crystals (the yield is more than 90%), and rectifying the centrifuged mother liquor (25-35 ℃) to recover the solvent to obtain distillate.

Further, the volume ratio of DMF to t-amyl alcohol in the step a is preferably 1: 4.

Further, the concentration of the sucrose in the step b is preferably 0.05-0.08 mmoL/mL.

Further, the concentration of the rhizomucor miehei lipase in the step b is 25-40 mg/mL.

Furthermore, the molar ratio of the sucrose to the vinyl acetate in the step b is preferably 1: 8-13.

The method takes sucrose as an initial raw material, synthesizes sucrose-6-acetate by lipase catalysis in a non-aqueous medium, and obtains the method by screening a reaction medium, lipase and an acyl donor and optimizing esterification reaction conditions, and the Rhizomucor miehei lipase can better catalyze vinyl acetate and sucrose to carry out esterification reaction in a DMF/tert-amyl alcohol system.

Compared with the prior art, the invention has the following advantages:

1. lipase can be combined with vinyl acetate into an intermediate compound, and can efficiently and specifically act on the hydroxyl at the 6 th position of sucrose to perform transesterification;

2. the combination of the rhizomucor miehei lipase and the vinyl acetate not only facilitates the correct positioning of a combined group and a catalytic group, but also performs early preparation work on the hydroxyl transesterification of the 6 th position of the sucrose for the next step of rhizomucor miehei lipase, and reduces the activation energy required for the sucrose molecule to reach the activated state;

3. the method has the advantages of simple production process, no isomer, low efficiency transesterification reaction with poor original selectivity, mild reaction conditions, simple operation, strong catalytic selectivity, good product safety, high conversion rate, low cost and the like.

Detailed Description

A method for synthesizing sucrose-6-acetate by Rhizomucor miehei lipase catalysis comprises the following specific implementation steps: