阅读说明：本技术 一种单宁酸生物催化合成没食子酸丙酯的方法 (Method for synthesizing propyl gallate through tannic acid biocatalysis ) 是由 张基明 杨长满 张洪滔 胡敬 黄泽琦 周婷婷 于 2020-06-12 设计创作，主要内容包括：本发明属于没食子酸丙酯合成技术领域,具体涉及一种单宁酸生物催化合成没食子酸丙酯的方法,以单宁酸为反应单体,以羧甲基纤维素钠固化单宁酶为催化剂,协同微波在有机溶剂中催化反应后,经减压蒸馏、冷却结晶、真空干燥,即得,本发明方法解决了生物催化法生产时间长、产率偏低的问题,并且本申请中没食子酸丙酯,并且操作简单易行,无大量废水废渣产生,且产物活性高,尤其是具有较好的抗氧化性能。(The invention belongs to the technical field of propyl gallate synthesis, and particularly relates to a method for synthesizing propyl gallate by tannic acid through biocatalysis.)

1. A method for synthesizing propyl gallate by tannic acid biocatalysis is characterized in that tannic acid is used as a reaction monomer, sodium carboxymethylcellulose-immobilized tannase is used as a catalyst, and the reaction is catalyzed in an organic solvent by cooperating with microwaves, and then the propyl gallate is obtained by reduced pressure distillation, cooling crystallization and vacuum drying.

2. The method for synthesizing propyl gallate by using tannic acid through biocatalysis as claimed in claim 1, wherein the mass ratio of the reaction monomer, the organic solvent and the catalyst in the synthesis process of propyl gallate is 1: (2-5): (0.8-1.3).

3. The method for the biocatalytic synthesis of propyl gallate with tannic acid of claim 1, wherein the organic solvent is n-butanol.

4. The method for the biocatalytic synthesis of propyl gallate with tannic acid of claim 1, wherein the sodium carboxymethyl cellulose immobilized tannase is prepared by: mixing the tannase solution and sodium carboxymethylcellulose at constant temperature of 25-35 deg.C, and shaking.

5. The method for synthesizing propyl gallate through tannic acid biocatalysis as claimed in claim 4, wherein the ratio of the tannase solution in the sodium carboxymethyl cellulose immobilized tannase to the sodium carboxymethyl cellulose is 1: (0.3-0.6).

6. The method for the biocatalytic synthesis of propyl gallate with tannic acid as claimed in claim 5, wherein the tannase solution is prepared by mixing commercially available tannase with water to a mass concentration of 50-70%, and adjusting the pH value to 6.3-6.7 with citric acid-sodium citrate solution.

7. The method for the biocatalytic synthesis of propyl gallate with tannic acid of claim 8, wherein the concentration of the tannase solution is 2000-.

8. The method for the biocatalytic synthesis of propyl gallate with tannic acid of claim 1, comprising the steps of:

1) preparing a tannic acid solution with the mass concentration of 60-80% in water, and performing ultrasonic dispersion with a catalyst for 5-10 min;

2) adding an organic solvent into the product obtained in the step 1), performing ultrasonic dispersion for 10-15min, heating to 40-45 ℃, performing heat preservation reaction for 16-20h, and filtering to recover the catalyst;

3) transferring the filtrate into a microwave kettle, performing microwave irradiation treatment for 3-5min under the condition of 120-260W, performing reduced pressure distillation to recover n-propanol, cooling, crystallizing, and vacuum drying to obtain propyl gallate.

9. The method for the biocatalytic synthesis of propyl gallate with tannic acid of claim 8, wherein the ultrasonic dispersion is at a power of 50-100W.

Technical Field

The invention belongs to the technical field of propyl gallate synthesis, and particularly relates to a method for synthesizing propyl gallate through tannic acid biocatalysis.

Background

Propyl gallate ((Propyl g gallate, PG) is white to light brown crystal powder or micro-emulsion white needle crystal, chemical name is 3,4, 5-trihydroxy benzoic acid Propyl ester, has good antioxidant performance, stronger antioxidant performance than tert-butyl hydroxy anisole and 2, 6-di-tert-butyl p-cresol, good heat resistance, is mainly used for antioxidation of grease or oil food and preservation of fruits and vegetables, can be used as biodiesel and antioxidant stabilizer or anti-aging agent of certain materials Has obvious effects on enhancing coronary blood flow and the like.

The existing method for producing propyl gallate has chemical catalysis and biotransformation, and the chemical catalysis has the disadvantages of high energy consumption, environmental pollution, long preparation time, more side reaction products and severe corrosion to equipment; the biotransformation reaction time is long, and the yield is low. More importantly, gallic acid is generally used as raw material to prepare propyl gallate through esterification in the traditional production, such as the research on the preparation of propyl gallate by aspergillus niger whole-cell biocatalysis (by the department of the amateur and the like) which utilizes aspergillus niger cells as a whole-cell biocatalyst to catalyze the production of propyl gallate, the microbiological method disclosed in the patent No. CN200410068174.8 in an organic phase synthesis mode to calculate propyl gallate, and the aspergillus niger is utilized to catalyze the synthesis of propyl gallate in an organic phase, but in fact, gallic acid is more expensive than propyl gallate, which undoubtedly increases the production cost.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for synthesizing propyl gallate by tannic acid biocatalysis.

The method is realized by the following technical scheme:

a method for synthesizing propyl gallate by tannic acid biocatalysis comprises the steps of taking tannic acid as a reaction monomer, taking sodium carboxymethylcellulose-immobilized tannase as a catalyst, performing catalytic reaction in an organic solvent in cooperation with microwaves, and then performing reduced pressure distillation, cooling crystallization and vacuum drying to obtain the propyl gallate.

In the synthesis process of the propyl gallate, the mass ratio of the reaction monomer, the organic solvent and the catalyst is 1: (2-5): (0.8-1.3).

The organic solvent is n-butanol.

The preparation method of the sodium carboxymethylcellulose-immobilized tannase comprises the following steps: mixing the tannase solution and sodium carboxymethylcellulose at constant temperature of 25-35 deg.C, and shaking.

The volume mass ratio of the tannase solution in the sodium carboxymethylcellulose solidified tannase to the sodium carboxymethylcellulose is 1: (0.3-0.6).

The tannase solution is prepared by preparing commercially available tannase and water into a solution with the mass concentration of 50-70%, and then adjusting the pH value to 6.3-6.7 by using a citric acid-sodium citrate solution.

The concentration of the tannase solution is 2000-3000U/mL.

Further, the method for synthesizing propyl gallate by tannic acid biocatalysis comprises the following steps:

1) preparing a tannic acid solution with the mass concentration of 60-80% in water, and performing ultrasonic dispersion with a catalyst for 5-10 min;

2) adding an organic solvent into the product obtained in the step 1), performing ultrasonic dispersion for 10-15min, heating to 40-45 ℃, performing heat preservation reaction for 16-20h, and filtering to recover the catalyst;

3) transferring the filtrate into a microwave kettle, performing microwave irradiation treatment for 3-5min under the condition of 120-260W, performing reduced pressure distillation to recover n-propanol, cooling, crystallizing, and vacuum drying to obtain propyl gallate.

And (3) ultrasonically dispersing, wherein the power of the ultrasonic dispersion is 50-100W.

Further, as a preferable mode, the catalyst of the present invention can also be preferably sulfonic acid resin/sodium carboxymethyl cellulose immobilized tannase, wherein the mass ratio of sodium carboxymethyl cellulose to sulfonic acid resin is 1: (0.2-0.4), uniformly mixing, and then defoaming in an oven at the temperature of 75 ℃ for 2 hours.

Has the advantages that:

the method solves the problems of long production time and low yield of a biocatalysis method, and the propyl gallate is simple and easy to operate, does not generate a large amount of waste water and waste residues, has high product activity and particularly has better oxidation resistance.

Tannase is an enzyme in a free state, has high environmental sensitivity, is unstable in strong acid, strong alkali, high temperature, high ion concentration and partial organic solvent, leads to enzyme protein denaturation, thereby reducing or even losing the catalytic activity of the tannase, and is not easy to separate from a substrate and a product after the completion of catalysis; according to the invention, sodium carboxymethylcellulose is used as a carrier to solidify tannase, so that the activity stability of the tannase can be improved, the heat-resistant range can be expanded, the enzyme activity can be ensured, the tannase can be recycled, and the tannase has lower activation energy. And the sodium carboxymethyl cellulose is insoluble in an organic solvent, so that the stability of a reaction system is facilitated. The sodium carboxymethylcellulose is utilized, and the wave absorbing frequency is wide, so that the wavelength emitted by ultrasonic treatment can be absorbed, the impurity substance can be adsorbed, the purity requirements of tannic acid and n-propanol in raw material preparation are reduced, and the oxidation resistance of the product is improved.

As a preferred scheme, the tannase is cured by using the sulfonic acid resin/sodium carboxymethyl cellulose, so that the reaction efficiency can be improved, the reaction time can be shortened, the curing capability of the tannase can be enhanced, and the phenomenon that the tannase is easy to leak or fall off from a carrier in the recycling process is effectively avoided.

The invention adopts the commercial tannase, has convenient raw material source, does not need to utilize aspergillus niger and the like for fermentation, and greatly shortens the production time.

Detailed Description

The following is a detailed description of the embodiments of the present invention, but the present invention is not limited to these embodiments, and any modifications or substitutions in the basic spirit of the embodiments are included in the scope of the present invention as claimed in the claims.