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

Preparation method of fumaric acid monoester

Technical Field

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

Background

With the improvement of the living standard of people and the rapid development of the food industry, food safety problems have attracted widespread attention throughout society. So far, the preservative in the food additive is one of the necessary functional components for industry development, can effectively protect the quality of food, prolong the shelf life of the food, and effectively control the breeding and decay of microorganisms in the food. However, with the long-term use of traditional preservatives, some related safety concerns also begin to emerge frequently.

At present, more traditional preservatives are used domestically are benzoic acid and sorbic acid. Although benzoic acid can have good antiseptic effect, certain toxicity exists, and excessive intake of benzoic acid can cause harm to human bodies and even cause toxic symptoms. As for sorbic acid, it is expensive and does not have a strong bacteriostatic effect for some microorganisms. Therefore, research and development of a novel safe, nontoxic, inexpensive, easy-to-prepare food preservative has become an important direction of industry development.

Among many new preservative studies, fumarate derivatives have been of interest. The alpha, beta-unsaturated carbonyl structure in the fumarate derivative is a functional group of the preservative to play an antibacterial role, and the fumarate is an antibacterial preservative containing the functional group. In practice, dimethyl fumarate has been found to give good results in feed mould proofing, but with slight toxicity. The fumaric acid monoester compound has the advantages of dimethyl fumarate, is smaller in toxicity and smaller in irritation to skin and mucous membrane, and is expected to become a novel preservative.

The traditional fumaric acid monoester production process has two methods: one is to esterify fumaric acid with alcohol in the presence of catalyst to produce fumaric monoester in one step. The process has the defects that fumaric acid monoester is easy to isomerize to generate fumaric acid diester, so that the separation between fumaric acid diester and fumaric acid monoester in the product is difficult, the subsequent purification process is complicated and complicated, and the purity of the fumaric acid monoester product is not high. The second production process is to take maleic anhydride as a starting material and acid as a catalyst to react with alcohol to generate maleic monoester; and then the fumaric acid monoester is generated under the action of an isomerization catalyst, and the yield of the fumaric acid monoester is lower although the method does not need to separate products.

Disclosure of Invention

The invention aims to provide a preparation method of fumaric acid monoester with higher yield, which specifically comprises the following technical scheme:

a method for preparing fumaric acid monoester, comprising the following steps:

s1, taking maleic anhydride and alcohol as reaction substrates, taking immobilized lipase as a catalyst, catalyzing transesterification reaction of the reaction substrates in an organic solvent to obtain reaction liquid, and carrying out suction filtration and distillation on the reaction liquid to obtain maleic monoester;

s2, catalyzing the isomerization of the maleic monoester obtained in the step S1 by taking aluminum chloride as a catalyst to obtain fumaric 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.

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

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

As a further preferred aspect, the immobilized lipase is lipase Novozyme435.

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

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

Preferably, the conditions for transferring the esterification reaction in step S1 are: the temperature is 30-60 ℃ and the time is 2-10h.

As a further preference, the conditions for transferring the esterification reaction in step S1 are: the temperature is 50 ℃ and the time is 8 hours.

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

As a further preferred aspect, the molar ratio of maleic anhydride to alcohol in step S1 is 1:2.

preferably, the distillation conditions in step S1 are 2000Pa,60 ℃.

Preferably, the conditions for isomerization in step S2 are: the temperature is 60-90 ℃ and the time is 1-4h.

As a further preference, the conditions for isomerisation in step S2 are: the temperature was 80℃for 3 hours.

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

and S3, recrystallizing the fumaric monoester obtained in the step S2 by using a methanol aqueous solution to obtain the purified fumaric monoester.

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

a fumaric acid monoester prepared using any of the above-described methods of preparation.

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

in the step S1, immobilized lipase is used as a catalyst for transesterification, and maleic monoester is synthesized by an enzymatic method, so that the yield of the maleic monoester, which is an intermediate product for preparing 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.

Drawings

For clarity of description of the embodiments, the drawings that follow are briefly described as follows:

FIG. 1 is a liquid chromatogram of a maleic anhydride standard;

FIG. 2 is a liquid chromatogram of a monoethyl maleate standard;

fig. 3 is a liquid chromatogram of a monoethyl fumarate standard.

Detailed Description

The invention will be further described by way of the following specific examples. Those of ordinary skill in the art will be able to implement the invention based on these descriptions. In addition, the embodiments of the present invention referred to in the following description are typically only some, but not all, embodiments of the present invention. Therefore, all other embodiments, which can be made by one of ordinary skill in the art without undue burden, are intended to be within the scope of the present invention, based on the embodiments of the present invention.

In the following examples, the detection conditions of the liquid chromatograph were (Waters 2695 liquid chromatograph): chromatographic column, AQ-C18,5um,4.6 x 250nm (zhejiang yue xu materials science, inc.); wavelength, 210nm; mobile phase, 0.01mol/L potassium dihydrogen phosphate: methanol (95:5, V/V); a flow rate of 1.000ml/min; column temperature, 26 ℃; detection time, 10min. The maleic anhydride peak time was 5.292min, the maleic monoethyl ester peak time was 6.202min, and the fumaric monoethyl ester peak time was 3.068min.

Example 1

In 4 sets of 10mL centrifuge tubes, a reaction substrate of 0.3g maleic anhydride and 0.38mL ethanol was dissolved in 3.6mL n-hexane organic solvent, 0.01g immobilized lipase Novozyme435 was added, the centrifuge tubes were closed, and the reaction was carried out at a constant temperature (30 ℃ C., 40 ℃ C., 50 ℃ C., 60 ℃ C.) for 8 hours at an oscillation rate of 200r/min, followed by sampling for liquid chromatography. The conversion rate of transesterification reaction was calculated and plotted to give the following table 1:

TABLE 1 results of enzyme catalysis at different reaction temperatures

Temperature (temperature)	Conversion of reaction (%)
		30℃	89.0％
40℃	92.4％
		50℃	96.5％
60℃	91.2％

As can be seen from the observation of Table 1, immobilized lipase Novozyme435 can well realize the catalysis of the reaction substrate at 30-60 ℃, and the conversion rate of maleic anhydride can reach more than 89%. In particular, when immobilized lipase Novozyme435 catalyzes transesterification of a reaction substrate at 50℃the reaction conversion was as high as 96.5%. Therefore, the enzyme catalysis method in the step S1 can effectively improve the yield of the intermediate product maleic monoester, and further indirectly improve the yield of fumaric monoester.

Example 2

In 5 groups of 10mL centrifuge tubes, different organic solvents (80% v/w, n-hexane, cyclohexane, toluene, petroleum ether, tert-butanol) were taken as reaction medium, and a reaction substrate containing 0.3g of maleic anhydride and 0.38mL of ethanol, and 0.01g of immobilized lipase Novozyme435 were added, the centrifuge tubes were closed, reacted for 8 hours at a shaking speed of 200r/min and a constant temperature of 50℃and then sampled for liquid chromatography analysis. And simultaneously calculating and drawing a conversion rate condition table of the transesterification reaction to obtain a table 2 as follows:

TABLE 2 enzymatic conversion results of different organic solvents

Organic solvents	Conversion of reaction (%)
		N-hexane	96.8％
Cyclohexane	84.5％
		Toluene (toluene)	92.6％
Petroleum ether	86.0％
		Tert-butanol	77.0％

It can be seen from an examination of Table 2 that the choice of organic solvent for the transesterification reaction will directly affect the yield of the intermediate maleic monoester, wherein the most preferred organic solvent is n-hexane, at which point the reaction conversion is up to 96.8% and when t-butanol organic solvent is chosen, the reaction conversion is only up to 77%.

Example 3

In 4 sets of 10mL centrifuge tubes, 0.3g of maleic anhydride and 0.38mL of ethanol as reaction substrates were dissolved in 3.6mL of n-hexane organic solvent, and the reaction tubes were closed with 0.01g of various immobilized lipases (lipase Novozyme435, lipase CALA, lipase RML, lipase TLL) as catalysts, and reacted at a shaking speed of 200r/min at a constant temperature of 50℃for 8 hours, followed by sampling for liquid chromatography analysis. And simultaneously calculating and drawing a conversion rate condition table of the transesterification reaction to obtain the following table 3:

TABLE 3 enzymatic conversion results of different lipases

Immobilized lipase	Manufacturer (S)	Conversion of reaction (%)
			Lipase Novozyme435	Denmark Norwestings Co Ltd	96.8％
Lipase CALA	Blue green island organism	93.5％
			Lipase RML	Blue green island organism	84.2％
Lipase TLL	Blue green island organism	89.0％

It can be seen from the observation of Table 3 that the selection of the immobilized lipase species will have a certain effect on the reaction conversion during the preparation of maleic acid monoesters by the enzyme-catalyzed transesterification reaction. Wherein, when lipase Novozyme435 is selected, the reaction conversion rate is the highest and reaches 96.8%, and when lipase RML is selected, the reaction conversion rate is the lowest and reaches 84.2%. The immobilized lipase in step S1 of the present invention is therefore preferably the lipase Novozyme435.

Example 4

In 3 groups of 10mL centrifuge tubes, 0.3g of maleic anhydride and 0.38mL of different alcohols (methanol, ethanol, butanol) were dissolved in 3.6mL of n-hexane organic solvent, the tubes were closed with 0.01g of lipase Novozyme435 as a catalyst, reacted at a shaking speed of 200r/min at a constant temperature of 50℃and then sampled for liquid chromatography. And simultaneously calculating and drawing a conversion rate condition table of the transesterification reaction to obtain the following table 4:

TABLE 4 enzymatic conversion results of different short-chain alcohols

Alcohols	Time (h)	Conversion (%)
			Methanol	6.5h	98.8％
Ethanol	8h	97.5％
			Butanol (Butanol)	10h	97.0％

As can be seen from the observation of Table 4, the lipase Novozyme435 can catalyze methanol, ethanol and butanol to generate maleic monoester, and the conversion rate is extremely high and reaches more than 95%.

Example 5

Maleic anhydride and ethanol in different molar ratios (see Table below) were dissolved in 3.6mL of n-hexane organic solvent in 3 groups of 10mL centrifuge tubes, the tubes were closed with 0.01g of lipase Novozyme435 as a catalyst, reacted for 8 hours at a shaking speed of 200r/min and a constant temperature of 50℃and then sampled for liquid chromatography. And simultaneously calculating and drawing a conversion rate condition table of the transesterification reaction to obtain the following table 5:

TABLE 5 results of enzymatic conversion at different molar ratios

Molar ratio of	Conversion (%)
		1∶6	90％
1∶2	96％
		1∶1	85％

As can be seen from the observation of Table 5, the reaction conversion was highest when the molar ratio of maleic anhydride to ethanol was 1:2.

Example 6

In 4 groups of 10mL centrifuge tubes, 0.3g of maleic anhydride and 0.38mL of ethanol were dissolved in 3.6mL of n-hexane organic solvent, the centrifuge tubes were closed with 0.01g of lipase Novozyme435 as a catalyst, and reacted for different times (2 hours, 4 hours, 8 hours, 10 hours) at a shaking speed of 200r/min and a constant temperature of 50℃and then sampled for liquid chromatography. And simultaneously calculating and drawing a conversion rate condition table of the transesterification reaction to obtain a table 6 as follows:

TABLE 6 enzymatic conversion results at different reaction times

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

It can be seen from the observation of Table 6 that the higher the conversion in the step of enzymatically preparing maleic acid monoester, the more the reaction time increases, however, the conversion differs by only 0.1% when the reaction is carried out for 8 hours and 10 hours, and thus the optimal reaction time for the transesterification reaction in step S1 is 8 hours, based on the reaction efficiency.

Example 7

Into 4 sets of 10mL centrifuge tubes, 10g of monomethyl maleate obtained in example 4 (methanol as a reaction substrate) and 0.25g of aluminum chloride were added, and the mixture was heated at different temperatures (60 ℃, 70 ℃, 80 ℃, 90 ℃) to isomerize for 3 hours to synthesize monomethyl fumarate, and the mixture was sampled and analyzed by liquid chromatography, and the conversion tables were calculated and plotted to obtain Table 7 as follows:

TABLE 7 influence of reaction temperature on the conversion of monomethyl fumarate

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

As can be seen from the observation of Table 7, the change in the isomerization reaction temperature will have a great influence on the conversion rate, specifically, when the isomerization temperature reaches 60 ℃, the conversion rate only reaches 78.5%, then as the temperature is continuously increased, the conversion rate is continuously increased until the reaction conversion rate reaches 99.2% at 80 ℃, and then when the temperature is increased, the conversion rate shows a tendency to decrease, and the optimal temperature for the isomerization reaction in the step S2 of the invention is 80 ℃.

Example 8

Into 4 groups of 10mL centrifuge tubes, 10g of monomethyl maleate obtained in example 4 (methanol as a reaction substrate) and 0.25g of aluminum chloride were added, and the mixture was heated at 80℃for various periods of time (1 h, 2h, 3h, 4 h) to synthesize monomethyl fumarate, and the mixture was sampled for liquid chromatography analysis, and the conversion tables were calculated and plotted to obtain Table 8 as follows:

TABLE 8 influence of reaction time on the conversion of monomethyl fumarate

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

It can be seen from the observation of Table 8 that the higher the conversion is as the reaction time increases, however, the conversion differs by only 0.1% when the reaction is carried out for 3 hours and 4 hours, so that the optimal reaction time for isomerization in step S2 is 3 hours based on the reaction efficiency.

Example 9

To 3 sets of 10mL centrifuge tubes, 10g of the maleic acid monoester obtained in example 4 (methanol as a reaction substrate), 0.25g of aluminum chloride were added, and the mixture was isomerized by heating at 80℃for 3 hours to synthesize fumaric acid monoester, and a sample was taken for liquid chromatography analysis. After the reaction is completed, cooling to room temperature to obtain the crude product of the fumaric monoester. Recrystallizing with 1:10 aqueous methanol solution to obtain purified fumaric monoester. The conversion and the product yield of this reaction are shown in Table 9.

Table 9, conversion and product yield Table

As can be seen from the above table, the yield of the fumaric acid monoester prepared by the preparation method is extremely high, and the technical problems of low conversion rate and low yield in the prior art can be effectively solved.

Claims (10)

1. A process for the preparation of a fumaric acid monoester comprising the steps of:

s1, taking maleic anhydride and alcohol as reaction substrates, taking immobilized lipase as a catalyst, catalyzing transesterification reaction of the reaction substrates in an organic solvent to obtain reaction liquid, and carrying out suction filtration and distillation on the reaction liquid to obtain maleic monoester;

s2, catalyzing the isomerization of the maleic monoester obtained in the step S1 by taking aluminum chloride as a catalyst to obtain fumaric monoester.

2. The method for producing fumaric acid monoester according to claim 1, wherein the alcohol in step S1 is one of methanol, ethanol and butanol.

3. The method of claim 1, wherein the immobilized lipase comprises one of lipase Novozyme435, lipase CALA, lipase RML or lipase TLL.

4. The method for producing fumaric acid monoester according to claim 1, wherein the organic solvent in step S1 comprises one of t-butanol, n-hexane, cyclohexane, toluene or petroleum ether.

5. The method for preparing fumaric acid monoester according to claim 1, wherein the conditions for transesterification in step S1 are as follows: the temperature is 30-60 ℃ and the time is 2-10h.

6. The method for producing fumaric acid monoester according to claim 1, wherein the molar ratio of maleic anhydride to alcohol in step S1 is 1 (1-6).

7. The method for synthesizing fumaric acid monoester according to claim 1, wherein the distillation conditions in step S1 are 2000pa,60 ℃.

8. The method for producing fumaric acid monoester according to claim 1, wherein the isomerization conditions in step S2 are: the temperature is 60-90 ℃ and the time is 1-4h.

9. The method for producing fumaric acid monoester according to claim 1, further comprising the steps of:

and S3, recrystallizing the fumaric monoester obtained in the step S2 by using a methanol aqueous solution to obtain the purified fumaric monoester.

10. A fumaric acid monoester prepared using the preparation process of any of claims 1-9.