CN117646042A - Preparation method of fumaric acid monoester - Google Patents

Abstract

The invention belongs to the technical field of biochemical engineering, and particularly relates to a preparation method of fumaric acid monoester. Compared with the prior art, the method has the advantages that the immobilized lipase is used as the catalyst of transesterification in the step S1, and the maleic monoester is synthesized by adopting an enzymatic method, so that the yield of the maleic monoester, which is an intermediate product for preparing the fumaric monoester, is greatly improved; on the basis, in the step S2, aluminum chloride is used as a catalyst for isomerization reaction to catalyze the intermediate product maleic monoester to isomerize, and the fumaric monoester is synthesized by a chemical method. The preparation method is simple and convenient to implement; the preparation condition is mild, and the preparation method is environment-friendly; and the preparation cost is low, the yield is high, and no byproducts are generated, so that a complex purification process is not required.

Description

A kind of preparation method of fumaric acid monoester

Technical field

The invention belongs to the technical field of biochemical engineering, and specifically relates to a preparation method of fumaric acid monoester.

Background technique

With the improvement of people's living standards and the rapid development of the food industry, food safety issues have attracted widespread attention from the whole society. So far, preservatives in food additives have always been one of the necessary functional ingredients for the development of the industry. They can effectively protect the quality of food, extend its shelf life, and effectively control the growth and decay of microorganisms in food. However, with the long-term use of traditional preservatives, some related safety hazards have begun to emerge frequently.

At present, the most commonly used traditional preservatives in China are benzoic acid and sorbic acid. Although benzoic acid can play a good preservative effect, it has a certain degree of toxicity. Excessive intake of benzoic acid can cause harm to the human body and even cause poisoning symptoms. As for sorbic acid, it is expensive and does not have a strong antibacterial effect on some microorganisms. Therefore, research and development of a new type of food preservative that is safe, non-toxic, cheap and easy to prepare has become an important direction for the development of the industry.

Among the many new preservatives research, fumarate derivatives have attracted much attention. The α,β-unsaturated carbonyl structure in fumarate derivatives is the functional group used by preservatives to exert antibacterial effects, and fumarate is an antibacterial preservative containing this functional group. In practice, research has found that dimethyl fumarate has achieved good results when used to prevent feed mildew, but it is slightly toxic. Fumaric acid monoester compounds have the advantages of dimethyl fumarate, are less toxic and less irritating to skin and mucous membranes, and are expected to become new preservatives.

There are two traditional fumaric acid monoester production processes: one is to esterify fumaric acid and alcohol under the action of a catalyst to generate fumaric acid monoester in one step. The disadvantage of this process is that fumaric acid monoester is easily isomerized to form fumaric acid diester, so the separation between fumaric acid diester and fumaric acid monoester in the product is difficult, and the subsequent purification process is cumbersome, complex, and rich. The purity of the maleic acid monoester product is not high. The second production process uses maleic anhydride as the starting material and acid as the catalyst to react with alcohol to generate maleic acid monoester; and then generate fumaric acid monoester under the action of the isomerization catalyst. Although This method does not require product isolation, but the yield of fumaric acid monoester is low.

Contents of the invention

The object of the present invention is to provide a method for preparing fumaric acid monoester with higher yield, specifically including the following technical solutions:

A preparation method of fumaric acid monoester, including the following steps:

S1. Use maleic anhydride and alcohol as reaction substrates, use immobilized lipase as catalyst, catalyze the transesterification reaction of the reaction substrate in an organic solvent to obtain a reaction liquid, and perform suction filtration and distillation of the reaction liquid to obtain maleic acid. Acid monoester;

S2. Use aluminum chloride as a catalyst to catalyze the isomerization of the maleic acid monoester obtained in step S1 to obtain fumaric acid monoester.

Compared with the prior art, in step S1 of the present invention, immobilized lipase is used as a catalyst for the transesterification reaction, and maleic acid monoester is synthesized by enzymatic method, which greatly improves the intermediate product of fumaric acid monoester preparation—— The yield of maleic acid monoester; on this basis, in step S2 of the present invention, aluminum chloride is also used as a catalyst for the isomerization reaction to catalyze the isomerization of the intermediate product maleic acid monoester, and chemically synthesize fumaric acid Monoester. This preparation method is simple and easy to implement; the preparation conditions are mild and environmentally friendly; the preparation cost is low, the yield is high, and there are no by-products, so there is no need for complex purification processes.

Preferably, the alcohol in step S1 includes one of methanol, ethanol, and butanol.

Preferably, the immobilized lipase includes one of lipase Novozyme435, lipase CALA, lipase RML or lipase TLL.

As a further preference, the immobilized lipase is lipase Novozyme435.

Preferably, the organic solvent in step S1 includes one of tert-butyl alcohol, n-hexane, cyclohexane, toluene or petroleum ether.

As a further preference, the organic solvent is n-hexane.

Preferably, the conditions for the transesterification reaction in step S1 are: temperature 30-60°C, time 2-10 h.

As a further preference, the conditions for the transesterification reaction in step S1 are: temperature 50°C, time 8 hours.

Preferably, the molar ratio of maleic anhydride and alcohol in step S1 is 1:(1-6).

As a further preference, the molar ratio of maleic anhydride and alcohol in step S1 is 1:2.

Preferably, the distillation conditions in step S1 are 2000 Pa and 60°C.

Preferably, the isomerization conditions in step S2 are: temperature 60-90°C, time 1-4h.

As a further preference, the isomerization conditions in step S2 are: temperature 80°C and time 3h.

Preferably, the preparation method of the fumaric acid monoester further includes the following steps:

S3. Use methanol aqueous solution to recrystallize the fumaric acid monoester obtained in S2 to obtain purified fumaric acid monoester.

As a further preference, the volume ratio of methanol to water in the methanol aqueous solution is 1:10.

A fumaric acid monoester prepared using any one of the above preparation methods.

Compared with the prior art, the present invention has the following beneficial effects:

In step S1 of the present invention, immobilized lipase is used as a catalyst for the transesterification reaction, and maleic acid monoester is synthesized by enzymatic method, which greatly improves the production of maleic acid monoester, an intermediate product in the preparation of fumaric acid monoester. rate; on this basis, in step S2 of the present invention, aluminum chloride is also used as a catalyst for the isomerization reaction to catalyze the isomerization of the intermediate product maleic acid monoester, and chemically synthesize fumaric acid monoester. This preparation method is simple and easy to implement; the preparation conditions are mild and environmentally friendly; the preparation cost is low, the yield is high, and there are no by-products, so there is no need for complex purification processes.

Description of drawings

In order to clearly explain the embodiment, the drawings of the accompanying drawings will be briefly introduced below:

Figure 1 is the liquid chromatogram of maleic anhydride standard;

Figure 2 is the liquid chromatogram of standard monoethyl maleate;

Figure 3 shows the liquid chromatogram of standard monoethyl fumarate.

Detailed ways

The present invention will be further described below and by way of specific examples. A person of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention mentioned in the following description are generally only some embodiments of the present invention, rather than all the embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts should fall within the scope of protection of the present invention.

In the following examples, the liquid chromatography detection conditions are (Waters2695 liquid chromatograph): chromatographic column, AQ-C18, 5um, 4.6*250nm (Zhejiang Yuexu Material Technology Co., Ltd.); wavelength, 210nm; mobile phase, 0.01mol/L potassium dihydrogen phosphate: methanol (95:5, V/V); flow rate, 1.000ml/min; column temperature, 26°C; detection time, 10min. The peak time of maleic anhydride is 5.292min, the peak time of monoethyl maleate is 6.202min, and the peak time of monoethyl fumarate is 3.068min.

Example 1

In four groups of 10mL centrifuge tubes, dissolve the reaction substrate of 0.3g maleic anhydride and 0.38mL ethanol in 3.6mL n-hexane organic solvent, add 0.01g immobilized lipase Novozyme 435, seal the centrifuge tubes, and incubate at 200r /min oscillation speed, constant temperature oscillation reaction at different temperatures (30°C, 40°C, 50°C, 60°C) for 8 hours, and then sampled for liquid chromatography analysis. Calculate and draw the conversion rate table of the transesterification reaction. Table 1 is as follows:

Table 1. Enzyme catalysis results at different reaction temperatures

temperature Reaction conversion rate (%) 30℃ 89.0% 40℃ 92.4% 50℃ 96.5% 60℃ 91.2%

By observing Table 1, it can be found that at 30-60°C, the immobilized lipase Novozyme 435 can effectively catalyze the reaction substrate, and the conversion rate of maleic anhydride reaches more than 89%. In particular, when the immobilized lipase Novozyme 435 catalyzed the transesterification reaction of the reaction substrate at 50°C, the reaction conversion rate was as high as 96.5%. It can be seen that the use of enzyme catalysis in step S1 of the present invention can effectively increase the yield of the intermediate product maleic acid monoester, thereby indirectly increasing the yield of fumaric acid monoester.

Example 2

In five groups of 10mL centrifuge tubes, take different organic solvents (80% v/w, n-hexane, cyclohexane, toluene, petroleum ether, tert-butanol) as reaction medium, and add 0.3g maleic anhydride and 0.38 mL of ethanol reaction substrate, and 0.01g of immobilized lipase Novozyme 435, in a sealed centrifuge tube, reacted for 8 hours at a shaking speed of 200 r/min and a constant temperature of 50°C, and then sampled for liquid chromatography analysis. At the same time, calculate and draw the conversion rate table of the transesterification reaction. Table 2 is as follows:

Table 2. Enzyme conversion results of different organic solvents

Organic solvents Reaction conversion rate (%) n-Hexane 96.8% cyclohexane 84.5% Toluene 92.6% Petroleum ether 86.0% tert-butyl alcohol 77.0%

By observing Table 2, it can be found that the selection of organic solvent for the transesterification reaction will directly affect the yield of the intermediate maleic acid monoester. The best organic solvent is n-hexane. At this time, the reaction conversion rate is as high as 96.8%. Tert-butyl is selected. When alcohol organic solvent was used, the reaction conversion rate only reached 77%.

Example 3

In four groups of 10mL centrifuge tubes, the reaction substrate of 0.3g maleic anhydride and 0.38mL ethanol was dissolved in 3.6mL n-hexane organic solvent, and 0.01g of different immobilized lipases (lipase Novozyme435, lipase CALA, Lipase RML, lipase TLL) were used as catalysts, the centrifuge tube was sealed, and the reaction was carried out at a shaking speed of 200 r/min and a constant temperature of 50°C for 8 hours, and then samples were taken for liquid chromatography analysis. At the same time, calculate and draw the conversion rate table of the transesterification reaction. Table 3 is as follows:

Table 3. Enzyme conversion results of different lipases

immobilized lipase manufacturer Reaction conversion rate (%) Lipase Novozyme435 Novozymes Denmark 96.8% Lipase CALA Qingdao Azure Biotechnology 93.5% lipaseRML Qingdao Azure Biotechnology 84.2% Lipase TLL Qingdao Azure Biotechnology 89.0%

By observing Table 3, it can be concluded that in the process of preparing maleic acid monoester using an enzyme-catalyzed transesterification reaction, the selection of the type of immobilized lipase will have a certain impact on the reaction conversion rate. Among them, when lipase Novozyme435 was used, the reaction conversion rate was the highest, reaching 96.8%, and when lipase RML was used, the reaction conversion rate was the lowest, reaching 84.2%. Therefore, the immobilized lipase in step S1 of the present invention is preferably lipase Novozyme435.

Example 4

In three groups of 10mL centrifuge tubes, dissolve 0.3g maleic anhydride and 0.38mL different alcohols (methanol, ethanol, butanol) in 3.6mL n-hexane organic solvent, use 0.01g lipase Novozyme435 as the catalyst, and seal the centrifuge tubes , reacted at a shaking speed of 200r/min and a constant temperature of 50°C, and then sampled for liquid chromatography analysis. At the same time, calculate and draw the conversion rate table of the transesterification reaction. Table 4 is as follows:

Table 4. Enzymatic conversion results of different short-chain alcohols

alcohol Time(h) Conversion rate(%) Methanol 6.5h 98.8% ethanol 8h 97.5% Butanol 10h 97.0%

By observing Table 4, it can be concluded that lipase Novozyme 435 can catalyze methanol, ethanol, and butanol to generate maleic acid monoester, and the conversion rate is extremely high, reaching more than 95%.

Example 5

In three groups of 10 mL centrifuge tubes, maleic anhydride and ethanol with different molar ratios (see the table below) were dissolved in 3.6 mL of n-hexane organic solvent, and 0.01g lipase Novozyme435 was used as a catalyst. The centrifuge tubes were sealed and heated at 200r /min shaking speed and a constant temperature of 50°C for 8 hours, and then samples were taken for liquid chromatography analysis. At the same time, calculate and draw the conversion rate table of the transesterification reaction. Table 5 is as follows:

Table 5. Enzyme conversion results at different molar ratios

The molar ratio of Conversion rate(%) 1:6 90% 1:2 96% 1:1 85%

By observing Table 5, it can be concluded that when the molar ratio of maleic anhydride to ethanol is 1:2, the reaction conversion rate is the highest.

Example 6

In 4 groups of 10mL centrifuge tubes, dissolve 0.3g maleic anhydride and 0.38mL ethanol in 3.6mL n-hexane organic solvent, use 0.01g lipase Novozyme435 as a catalyst, seal the centrifuge tubes, and oscillate at a shaking speed of 200r/min. The reaction was carried out for different times (2h, 4h, 8h, 10h) under constant temperature conditions of 50°C, and then samples were taken for liquid chromatography analysis. At the same time, calculate and draw the conversion rate table of the transesterification reaction. Table 6 is as follows:

Table 6. Enzyme conversion results at different reaction times

Reaction time Conversion rate(%) 2h 64.5% 4h 76.6% 8h 96.5% 10h 96.6%

By observing Table 6, it can be concluded that in the enzyme-catalyzed preparation of maleic acid monoester, as the reaction time continues to increase, the conversion rate becomes higher. However, when the reaction is 8h and the reaction is 10h, the conversion rate difference is only 0.1%, so Based on reaction efficiency considerations, the optimal reaction time for the transesterification reaction in step S1 is 8 h.

Example 7

In four groups of 10 mL centrifuge tubes, add 10 g of monomethyl maleate obtained in Example 4 (methanol as the reaction substrate) and 0.25 g of aluminum chloride, at different temperatures (60°C, 70°C, 80°C , 90°C), heat for isomerization for 3 hours, synthesize monomethyl fumarate, take samples for liquid chromatography analysis, and calculate and draw the conversion rate table. Table 7 is as follows:

Table 7. Effect of reaction temperature on conversion rate of monomethyl fumarate

temperature Conversion rate(%) 60℃ 78.5% 70℃ 88.4% 80℃ 99.2% 90℃ 95.6%

By observing Table 7, it can be concluded that changes in the isomerization reaction temperature will have a greater impact on the conversion rate. Specifically, when the isomerization temperature reaches 60°C, the conversion rate only reaches 78.5%, and then as the temperature The conversion rate continues to increase until 80°C, the conversion rate of the reaction is as high as 99.2%, and then when the temperature is raised, the conversion rate shows a decreasing trend. It can be seen that the isomerization reaction in step S2 of the present invention is optimal. The temperature is 80℃.

Example 8

In four groups of 10 mL centrifuge tubes, add 10 g of monomethyl maleate obtained in Example 4 (methanol as the reaction substrate) and 0.25 g of aluminum chloride, and heat to isomerize at 80° C. for different times (1 h, 2h, 3h, 4h), synthesize monomethyl fumarate, take samples for liquid chromatography analysis, and calculate and draw a conversion rate table. Table 8 is as follows:

Table 8. Effect of reaction time on conversion rate of fumarate monomethyl ester

Reaction time(h) Conversion rate(%) 1h 68.6% 2h 86.2% 3h 99.4% 4h 99.5%

By observing Table 8, it can be concluded that as the reaction time continues to increase, the conversion rate becomes higher. However, when the reaction is 3h and the reaction is 4h, the difference in conversion rate is only 0.1%. Therefore, based on the reaction efficiency, the isomerization in step S2 The optimal reaction time is 3h.

Example 9

In three groups of 10 mL centrifuge tubes, add 10 g of the maleic acid monoester obtained in Example 4 (methanol as the reaction substrate) and 0.25 g of aluminum chloride, and heat and isomerize at 80°C for 3 hours to synthesize fumaric acid monoester. Esters, samples were taken for liquid chromatography analysis. After the reaction is complete, cool to room temperature to obtain crude fumaric acid monoester. Purified fumaric acid monoester can be obtained by recrystallizing with a 1:10 methanol aqueous solution. The conversion rate and product yield of this reaction are shown in Table 9.

Table 9. Conversion rate and product yield table

It can be seen from the above table that the yield of fumaric acid monoester prepared using the preparation method of the present invention is extremely high, which can effectively solve the technical problems of low conversion rate and low yield in the prior art.

Claims (10)

1. A preparation method of fumaric acid monoester, characterized in that it includes the following steps: S1. Use maleic anhydride and alcohol as reaction substrates, use immobilized lipase as catalyst, catalyze the transesterification reaction of the reaction substrate in an organic solvent to obtain a reaction liquid, and perform suction filtration and distillation of the reaction liquid to obtain maleic acid. acid monoester; S2. Use aluminum chloride as a catalyst to catalyze the isomerization of the maleic acid monoester obtained in step S1 to obtain fumaric acid monoester. 2. The method for preparing fumaric acid monoester according to claim 1, wherein the alcohol in step S1 is one of methanol, ethanol, and butanol. 3. The preparation method of a kind of fumaric acid monoester according to claim 1, characterized in that the immobilized lipase includes one of lipase Novozyme435, lipase CALA, lipase RML or lipase TLL. . 4. The preparation method of a kind of fumaric acid monoester according to claim 1, characterized in that the organic solvent described in step S1 includes one of tert-butyl alcohol, n-hexane, cyclohexane, toluene or petroleum ether. kind. 5. The preparation method of a fumaric acid monoester according to claim 1, characterized in that the conditions of the transesterification reaction in step S1 are: temperature 30-60°C, time 2-10h. 6. The preparation method of a kind of fumaric acid monoester according to claim 1, characterized in that the molar ratio of maleic anhydride and alcohol in step S1 is 1: (1-6). 7. A method for synthesizing fumaric acid monoester according to claim 1, characterized in that the distillation conditions in step S1 are 2000 Pa and 60°C. 8. The preparation method of fumaric acid monoester according to claim 1, characterized in that the isomerization conditions in step S2 are: temperature 60-90°C, time 1-4h. 9. the preparation method of a kind of fumaric acid monoester according to claim 1, is characterized in that, also comprises the following steps: S3. Use methanol aqueous solution to recrystallize the fumaric acid monoester obtained in S2 to obtain purified fumaric acid monoester. 10. A fumaric acid monoester prepared by any one of the preparation methods of claims 1-9.