CN110839629A

CN110839629A - Preparation method and application of efficient antibacterial bactericide for melons, fruits and vegetables

Info

Publication number: CN110839629A
Application number: CN201910839263.4A
Authority: CN
Inventors: 付贤树; 叶子弘; 俞晓平; 崔海峰; 张雅芬; 夏文强
Original assignee: China Jiliang University
Current assignee: China Jiliang University
Priority date: 2019-09-05
Filing date: 2019-09-05
Publication date: 2020-02-28

Abstract

The invention discloses a preparation method and application of a high-efficiency antibacterial bactericide for fruits and vegetables. The preparation method comprises the following steps: (A) fully dissolving 1 part by weight of polyvinylamine into 50-300 parts by weight of solvent at normal temperature, and adding 0.2-2 parts by weight of difluorobenzoic acid to completely dissolve; (B) adding 0.2-2.0 parts by weight of coupling agent under nitrogen to react for 1-6 hours at 20-70 ℃, and controlling the pH value of the system by using a pH value regulator; (C) separating the reaction solution by a dialysis bag for 1-5 days, and drying to obtain a purified product; (D) adding 0.01-0.1 weight part of rare earth as a synergist, and uniformly mixing to obtain a final product. The bactericidal composition can be used for antibacterial sterilization of fruits and vegetables, has obvious antibacterial and bactericidal effects on enterobacter and gram-negative bacteria, achieves 100.0% bactericidal rate under 1-10 mg/L, has low residual rate, and does not threaten the health of people and livestock.

Description

Preparation method and application of efficient antibacterial bactericide for melons, fruits and vegetables

Technical Field

The invention relates to the field of preparation and application of agricultural and sideline products, in particular to a preparation method and application of a difluorobenzene functional group-containing polyvinylamine antibacterial bactericide.

Background

Along with the gradual improvement of the living standard of people, the requirements of people on sanitation and health are higher and higher, especially for the consumption of agricultural products. The antibacterial bactericide is a common agricultural and sideline product, and can play a role in inhibiting the growth of microorganisms and killing the microorganisms, thereby ensuring the quality of agricultural products. The existing antibacterial agents can be divided into three types, namely natural antibacterial agents, inorganic antibacterial agents and organic antibacterial agents.

Natural antimicrobial agents are less useful due to limitations in their antimicrobial effectiveness, stability, and price. Although inorganic antibacterial agents have the advantage of good heat resistance, they are expensive and have antibacterial activity-delaying properties, and their market is shrinking. Compared with inorganic products, the organic polymer antibacterial agent has the advantages of small dosage, strong antibacterial activity, good safety and stability, wide application range, small influence from external environment and the like due to larger molecular weight, and has larger and larger application market and wide attention and application in the field of agricultural and sideline products. Common organic antimicrobial agents include: quaternary ammonium salts, quaternary phosphonium salts, phenolic compounds, and the like. Therefore, the development of the novel polymer antibacterial agent meets the development requirement of the market and has great practical application value.

Disclosure of Invention

The invention aims to provide a preparation and application method of a high-efficiency antibacterial bactericide for melons, fruits and vegetables, which has the advantages of excellent performance, simple process and low cost.

In order to solve the technical problem, the invention grafts difluorobenzoic acid on a macromolecular polyvinylamine molecular skeleton through a grafting reaction, and then uses rare earth as a synergist for compounding. The method can effectively improve the capability of the antibacterial bactericide for killing germs in fruits and vegetables.

The invention is realized by the following technical scheme:

(A) mixing 1 part by weight of polyvinylamine and 50-300 parts by weight of a solvent at normal temperature and fully stirring to fully dissolve the polyvinylamine; then, 0.2 to 2 parts by weight of difluorobenzoic acid is added thereto and sufficiently dissolved in the solution.

(B) Adding 0.2-2.0 parts by weight of coupling agent into the solution under the protection of nitrogen for reaction for 1-6 hours at 20-70 ℃. During the reaction, pH regulator is used to control the pH value of the solution system.

(C) After the reaction is finished, the reaction solution is collected into a dialysis membrane for separation, the separation time is 1 to 5 days, and then the solution is dried.

(D) And adding 0.01-0.1 part by weight of rare earth serving as a synergist into the purified product, and uniformly mixing to obtain a final product.

The solvent is one or a mixture of more of water, methanol, ethanol, N-dimethylformamide or isopropanol.

The pH value regulator is one or more selected from hydrochloric acid, acetic acid, oxalic acid, sodium hydroxide, ammonia water and sodium bicarbonate. The pH value of the reaction solution system should be kept between 3.0 and 10.0.

The coupling agent is preferably N, N' -dicyclohexylcarbodiimide, 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride or diisopropylcarbodiimide.

The rare earth synergist is preferably lanthanum trichloride, cerium tetrachloride and neodymium chloride.

The optimal substitution degree of the phenylboronic acid group to the polyvinylamine is 20-35% (molar ratio).

The invention also provides a verification result of the product used as an antibacterial bactericide. The using concentration of the product is generally 1 mg/L-10 mg/L.

Compared with the prior art, the invention has the advantages that: the invention provides a preparation technology of a high-molecular antibacterial bactericide containing difluorobenzene functional groups, and the grafted product has strong inhibition capability on bacteria such as escherichia coli, gram-negative bacteria and the like and low residue rate, and does not threaten the health of people and livestock. Therefore, the product can be used as an antibacterial bactericide for agricultural and sideline products. In addition, the invention has the advantages of simple and mature process, low production cost and easy control of operation.

Detailed Description

The invention will be further described with reference to specific examples, but the scope of the invention is not limited thereto:

example 1:

at normal temperature, 10 g of polyvinylamine is added into a reaction kettle, then 1000 ml of water is added, after uniform mixing, 10 g of difluorobenzoic acid is added, and stirring is continued. After 50 minutes, the temperature is raised to 40 ℃, 0.1M dilute hydrochloric acid is added to adjust the pH value of the solution to 6.0, 10 g of 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride is slowly added under the protection of nitrogen, and after stirring for 3 hours, the temperature is reduced and discharging is carried out. The reaction solution was separated and purified by dialysis membrane for 3 days, and after drying, 0.2g of lanthanum trichloride was added to the product and stirred uniformly to obtain the final product 1.

Example 2:

at normal temperature, 10 g of polyvinylamine is added into a reaction kettle, then 1000 ml of water and 100 ml of ethanol are added, after uniform mixing, 5 g of difluorobenzoic acid is added, and stirring is continued. After 90 minutes, the temperature is raised to 65 ℃, acetic acid is added to adjust the pH value of the solution to 4.0, 18 g of 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride is slowly added under the protection of nitrogen, and after stirring for 4 hours, the temperature is reduced and discharging is carried out. The reaction solution was separated and purified by a dialysis membrane for 2 days, and after drying, 0.4g of neodymium chloride was added to the product and stirred uniformly to obtain a final product 2.

Example 3:

at normal temperature, 10 g of polyvinylamine is added into a reaction kettle, then 800 ml of water and 25 ml of methanol are added, after uniform mixing, 4g of difluorobenzoic acid is added, and stirring is continued. After 60 minutes, the temperature is raised to 35 ℃, 0.1M oxalic acid is added to adjust the pH value of the solution to 5.0, 5 g of diisopropylcarbodiimide is slowly added under the protection of nitrogen, the mixture is stirred for 2 hours, and then the temperature is reduced and the material is discharged. The reaction solution was separated and purified by dialysis membrane for 4 days, and after drying, 0.6g of cerium tetrachloride was added to the product and stirred uniformly to obtain the final product 3.

Example 4:

at normal temperature, 10 g of polyvinylamine is added into a reaction kettle, then 1500 ml of water and 50 ml of isopropanol are added, after uniform mixing, 15 g of difluorobenzoic acid is added, and stirring is continued. After 80 minutes, the temperature is raised to 50 ℃, 0.1M dilute sodium hydroxide is added to adjust the pH value of the solution to 7.8, 2.0 g of diisopropylcarbodiimide is slowly added under the protection of nitrogen, stirred for 4 hours, cooled and discharged. The reaction solution was separated and purified by a dialysis membrane for 2 days, and after drying, 0.8g of lanthanum trichloride was added to the product and stirred uniformly to obtain a final product 4.

Example 5:

at normal temperature, 10 g of polyvinylamine is added into a reaction kettle, then 1000 ml of water and 250 ml of N, N-dimethylformamide are added, and after uniform mixing, 12 g of difluorobenzoic acid is added and stirring is continued. After 100 minutes, heating to 40 ℃, adding dilute ammonia water to adjust the pH value of the solution to 8.5, slowly adding 8.0 g of N, N' -dicyclohexylcarbodiimide under the protection of nitrogen, stirring for 3 hours, cooling and discharging. The reaction solution was separated and purified by dialysis membrane for 4 days, dried, and then 1g of neodymium chloride was added to the product and stirred uniformly to obtain a final product 5.

Example 6:

at normal temperature, 10 g of polyvinylamine is added into a reaction kettle, then 1000 ml of water and 250 ml of N, N-dimethylformamide are added, and after uniform mixing, 12 g of difluorobenzoic acid is added and stirring is continued. After 100 minutes, heating to 80 ℃, adding diluted ammonia water to adjust the pH value of the solution to 8.5, slowly adding 8.0 g of N, N' -dicyclohexylcarbodiimide under the protection of nitrogen, stirring for 3 hours, cooling and discharging. The reaction solution was separated and purified by dialysis membrane for 4 days, dried, and then 1g of neodymium chloride was added to the product and stirred uniformly to obtain a final product 6.

Example 7:

the final products 1 to 6 prepared in the above examples 1 to 6 were subjected to inhibition experiments on escherichia coli, gram negative bacteria, cucumber fusarium wilt bacteria, watermelon leaf spot bacteria and the like, and the antibacterial and bactericidal effects were verified. The results are shown in Table 1.

Table 1 bacteriostatic effect of the antibacterial bactericide prepared by the present invention against 7 pathogenic bacteria

As can be seen from Table 1, the 5 antibacterial bactericides of 1-5 final products prepared by the method have high-efficiency bactericidal action, and the bactericidal rate to escherichia coli and gram-negative bacteria reaches 100.0 percent; although the preparation method of the final product 6 is not in the protection scope of the invention, and the antibacterial sterilization rate of the final product 6 to the Colletotrichum phaseoloides is the lowest and is 62.4%, the inhibition rate is far higher than the sterilization effect of the general antibacterial bactericide on the market at present.

Claims

1. A preparation method of a high-efficiency antibacterial bactericide for fruits and vegetables is characterized by comprising the following steps:

(A) mixing and stirring 1 part by weight of polyvinylamine and 50-300 parts by weight of a solvent at normal temperature to fully dissolve the polyvinylamine; then adding 0.2-2 parts by weight of difluorobenzoic acid and completely dissolving;

(B) adding 0.2-2.0 parts by weight of coupling agent into the solution under the protection of nitrogen for reaction, wherein the reaction time is 1-6 hours, the reaction temperature is 20-70 ℃, and a pH value regulator is required to be used for controlling the pH value of a solution system in the reaction process;

(C) after the reaction is finished, collecting the reaction solution into a dialysis membrane for separation, wherein the separation time is 1-5 days, and then drying the solution;

(D) and adding 0.01-0.1 part by weight of rare earth serving as a synergist into the purified product, and uniformly mixing to obtain the final product.

2. The preparation method of the high-efficiency antibacterial bactericide for fruits and vegetables as claimed in claim 1, wherein the high-efficiency antibacterial bactericide is an antibacterial bactericide containing difluorobenzene functional group, and the preparation method is characterized in that: the solvent is one or a mixture of more of water, methanol, ethanol, N-dimethylformamide or isopropanol.

3. The method for preparing a high-efficiency antibacterial bactericide for fruits and vegetables as claimed in claim 1, wherein the pH value regulator is selected from one or more of hydrochloric acid, acetic acid, oxalic acid, sodium hydroxide, ammonia water and sodium bicarbonate, and the pH value of the reaction solution system should be kept between 3.0-10.0.

4. The method for preparing a high-efficiency antibacterial bactericide for melon, fruit and vegetable as claimed in claim 1, wherein said polyvinyl amine polymer grafted with difluorophenyl group is used as the high-efficiency antibacterial bactericide for melon, fruit and vegetable, and said coupling agent is preferably N, N' -dicyclohexylcarbodiimide, 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride, diisopropylcarbodiimide.

5. The method for preparing efficient antibacterial bactericide for melons, fruits and vegetables as claimed in claim 1, wherein polyvinylamine polymer melons, fruits and vegetables grafted with difluorophenyl group is used as the efficient antibacterial bactericide, and the rare earth synergist is preferably lanthanum trichloride, cerium tetrachloride or neodymium chloride.

6. The difluorobenzene functional polyvinyl amine polymer antibacterial bactericide prepared by the method of any one of claims 1 to 4 belongs to the protection scope of the invention.

7. The method for preparing efficient antibacterial bactericide for fruits and vegetables as claimed in claim 1, wherein the optimal substitution degree of difluorobenzoic acid of the polyvinylamine molecule grafted with difluorobenzoic acid is 20-35% (molar ratio).

8. The polyvinyl amine polymer grafted with difluorobenzoic acid according to claim 5 or 6, which is used as an antibacterial and bactericidal agent for fruits and vegetables.

9. The method of claim 8, wherein the polyvinyl amine polymer antibacterial fungicide having difluorobenzene functional group comprises: the using concentration of the antibacterial bactericide is 1 mg/L-10 mg/L according to the difference of the colony number in the fruits and vegetables.