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

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

A kind of preparation method and application of high-efficiency antibacterial fungicide 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 polyvinylamine antibacterial fungicide containing a difluorobenzene functional group. The organic polymer antibacterial fungicide can be used as an efficient antibacterial fungicide for fruits and vegetables.

Background technique

With the gradual improvement of people's living standards, people's requirements for hygiene and health are getting higher and higher, especially for the consumption of agricultural products. Antibacterial fungicide is a common agricultural and sideline product, which can inhibit the growth of microorganisms and eliminate microorganisms, thereby ensuring the quality of agricultural products. Existing antibacterial agents can be divided into three categories: natural antibacterial agents, inorganic antibacterial agents and organic antibacterial agents.

Due to the limitation of antibacterial effect, stability and price, the application of natural antibacterial agents is less. Inorganic antibacterial agents have the advantage of good heat resistance, but their price is high and there is a delay in antibacterial effect, and their market is gradually shrinking. Compared with inorganic products, organic macromolecular antibacterial agents have the advantages of large molecular weight, low dosage, strong antibacterial activity, good safety and stability, wide application range, and little impact on the external environment. The bigger it is, it has also received extensive attention and application in the field of agricultural and sideline products. Common organic antibacterial agents include: quaternary ammonium salts, quaternary phosphorus salts, phenolic compounds, etc. Therefore, the development of new polymer antibacterial agents is in line with the needs of market development and has great practical application value.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation and application method of an efficient antibacterial fungicide for fruits and vegetables with excellent performance, simple process and low cost.

In order to solve the above technical problems, the present invention grafts difluorobenzoic acid on the molecular skeleton of high molecular polyvinylamine through a grafting reaction, and then uses rare earth as a synergist for compounding. The method can effectively improve the ability of the antibacterial fungicide to kill germs in fruits and vegetables.

The present invention is achieved through the following technical solutions:

(A) Mix 1 part by weight of polyvinylamine and 50 to 300 parts of solvent at room temperature and stir well to dissolve it; then add 0.2 to 2 parts by weight of difluorobenzoic acid and make it fully dissolved in the solution among.

(B) 0.2-2.0 parts by weight of a coupling agent is added to the solution under nitrogen protection for reaction, the reaction time is 1-6 hours, and the reaction temperature is 20-70°C. During the reaction, a pH regulator should be used to control the pH value of the solution system.

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

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

The solvent is selected from one or more mixtures of water, methanol, ethanol, N,N-dimethylformamide or isopropanol.

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

The coupling agent is preferably N,N'-dicyclohexylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, diisopropyl carbon Diimine.

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

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

The invention also provides the verification result that the product is used as an antibacterial bactericide. The concentration of this product is generally 1mg/L ~ 10mg/L.

Compared with the prior art, the present invention has the advantages that: the present invention provides a technology for preparing a polymer antibacterial bactericide containing a difluorobenzene functional group, and the graft product has the ability to inhibit pathogens such as Escherichia coli and Gram-negative bacteria. Strong and low residual rate, will not pose a threat to the health of humans and animals. Therefore, the product can be used as an antibacterial fungicide for agricultural and sideline products. In addition, the process of the invention is simple and mature, the production cost is low, and the operation is easy to control.

Detailed ways

The present invention is further described below in conjunction with specific embodiment, but the protection scope of the present invention is not limited to this:

Example 1:

Add 10 grams of polyvinylamine to the reactor at room temperature, then add 1000 milliliters of water, mix evenly, add 10 grams of difluorobenzoic acid, and continue stirring. After 50 minutes, the temperature was raised to 40°C, 0.1M dilute hydrochloric acid was added to adjust the pH of the solution to 6.0, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride was slowly added under nitrogen protection. 10 grams, after stirring for 3 hours, cool down and discharge. The reaction solution was separated and purified by a dialysis membrane for 3 days. After drying, 0.2 g of lanthanum trichloride was added to the product and stirred evenly to obtain the final product 1.

Example 2:

Add 10 grams of polyvinylamine to the reaction kettle at normal temperature, then add 1000 milliliters of water and 100 milliliters of ethanol, mix evenly, add 5 grams of difluorobenzoic acid, and continue stirring. After 90 minutes, the temperature was raised to 65°C, acetic acid was added to adjust the pH of the solution to 4.0, and 18 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride was slowly added under nitrogen protection, After stirring for 4 hours, cool down and discharge. The reaction solution was separated and purified by a dialysis membrane for 2 days. After drying, 0.4 g of neodymium chloride was added to the product and stirred evenly to obtain the final product 2.

Example 3:

Add 10 grams of polyvinylamine in the reaction kettle at normal temperature, then add 800 milliliters of water and 25 milliliters of methanol, add 4 grams of difluorobenzoic acid after mixing evenly, and continue to stir. After 60 minutes, the temperature was raised to 35° C., 0.1 M oxalic acid was added to adjust the pH value of the solution to 5.0, and 5 g of diisopropylcarbodiimide was slowly added under nitrogen protection. After stirring for 2 hours, the temperature was lowered and the material was discharged. The reaction solution was separated and purified by a dialysis membrane for 4 days, and after drying, 0.6 g of cerium tetrachloride was added to the product and stirred uniformly to obtain the final product 3.

Example 4:

Add 10 grams of polyvinylamine in the reaction kettle at normal temperature, then add 1500 milliliters of water and 50 milliliters of isopropanol, add 15 grams of difluorobenzoic acid after mixing and continue to stir. After 80 minutes, the temperature was raised to 50° C., 0.1M dilute sodium hydroxide was added to adjust the pH value of the solution to 7.8, and 2.0 g of diisopropylcarbodiimide was slowly added under nitrogen protection. After stirring for 4 hours, the temperature was lowered and the material was discharged. The reaction solution was separated and purified by a dialysis membrane for 2 days. After drying, 0.8 g of lanthanum trichloride was added to the product and stirred evenly to obtain the final product 4.

Example 5:

10 grams of polyvinylamine were added to the reactor at normal temperature, then 1000 milliliters of water and 250 milliliters of N,N-dimethylformamide were added, and 12 grams of difluorobenzoic acid were added after mixing and continued stirring. After 100 minutes, the temperature was raised to 40°C, diluted ammonia water was added to adjust the pH value of the solution to 8.5, and 8.0 g of N,N'-dicyclohexylcarbodiimide was slowly added under nitrogen protection, stirred for 3 hours, and then cooled and discharged. The reaction solution was separated and purified by a dialysis membrane for 4 days. After drying, 1 g of neodymium chloride was added to the product and stirred evenly to obtain the final product 5.

Example 6:

10 grams of polyvinylamine were added to the reactor at normal temperature, then 1000 milliliters of water and 250 milliliters of N,N-dimethylformamide were added, and 12 grams of difluorobenzoic acid were added after mixing and continued stirring. After 100 minutes, the temperature was raised to 80°C, dilute aqueous ammonia was added to adjust the pH of the solution to 8.5, and 8.0 g of N,N'-dicyclohexylcarbodiimide was slowly added under nitrogen protection, stirred for 3 hours, and then cooled and discharged. The reaction solution was separated and purified by a dialysis membrane for 4 days. After drying, 1 g of neodymium chloride was added to the product and stirred evenly to obtain the final product 6.

Example 7:

The final products 1-6 prepared in the above Examples 1-6 were subjected to inhibition experiments on Escherichia coli, Gram-negative bacteria, Cucumber Fusarium wilt, Watermelon Leaf Spot, etc. to verify the antibacterial and bactericidal effect. The results are shown in Table 1.

Table 1 The antibacterial bactericidal effect table of the antibacterial bactericide prepared by the present invention to 7 kinds of pathogenic bacteria

As can be seen from Table 1, the final products 1-5 prepared by the method of the present invention, these 5 kinds of antibacterial fungicides have efficient bactericidal effect, and the bactericidal rate against Escherichia coli and Gram-negative bacteria reaches 100.0%; the final product Although the preparation method of 6 is not within the protection scope of the patent of the present invention, and the final product 6 has the lowest antibacterial and sterilization rate to bean anthracnose bacteria, which is 62.4%, but the inhibition rate is also far higher than the sterilization effect of the current general antibacterial fungicides on the market.

Claims (9)

1. a kind of preparation method of melon, fruit and vegetable efficient antibacterial bactericide, is characterized in that, described method may further comprise the steps: (A) 1 weight part of polyvinylamine and 50～300 parts of solvent are mixed at normal temperature and stirred to be fully dissolved; 0.2～2 weight part of difluorobenzoic acid is then added and completely dissolved; (B) adding the coupling agent of 0.2～2.0 weight part to this solution under nitrogen protection to carry out the reaction, the reaction time is 1～6 hours, the reaction temperature is 20～70 ℃, needs to use the pH regulator in the reaction process To control the pH value of the solution system; (C) after the end of the reaction, the reaction solution is collected in the dialysis membrane for separation, and the separation time is 1-5 days, and the solution is subsequently dried; (D) adding 0.01-0.1 parts by weight of rare earth to the purified product as a synergist and mixing uniformly to obtain the final product. 2. a kind of high-efficiency antibacterial bactericide preparation method for fruits and vegetables as claimed in claim 1, it is characterized in that described high-efficiency antibacterial bactericide is the antibacterial bactericide containing difluorobenzene functional group, and its preparation method is characterized in that: Said solvent is selected from one or more mixtures of water, methanol, ethanol, N,N-dimethylformamide or isopropanol. 3. a kind of high-efficiency antibacterial bactericide preparation method for fruits and vegetables as claimed in claim 1, is characterized in that described pH regulator is selected from among hydrochloric acid, acetic acid, oxalic acid, sodium hydroxide, ammoniacal liquor and sodium bicarbonate One or more, the pH value of the reaction solution system should be maintained between 3.0 and 10.0. 4. the preparation method of a kind of efficient antibacterial bactericide for fruits and vegetables as claimed in claim 1, it is characterized in that the preparation of described polyvinylamine macromolecular fruits and vegetables efficient antibacterial bactericide grafted with difluorophenyl group method, the coupling agent is preferably N,N'-dicyclohexylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, diisopropylcarbodiimide carbodiimide. 5. the preparation method of a kind of efficient antibacterial bactericide for fruits and vegetables as claimed in claim 1, it is characterized in that the preparation of described polyvinylamine macromolecular fruits and vegetables efficient antibacterial bactericide grafted with difluorophenyl group method, the rare earth synergist is preferably lanthanum trichloride, cerium tetrachloride and neodymium chloride. 6. The polyvinylamine macromolecular antibacterial bactericidal agent containing difluorobenzene functional groups prepared by the method of any one of claims 1-4, all fall within the protection scope of the present invention. 7. the preparation method of a kind of efficient antibacterial bactericide for fruits and vegetables as claimed in claim 1, it is characterized in that the polyvinylamine molecule after the described difluorobenzoic acid grafting, the optimal degree of substitution of its difluorobenzoic acid 20 to 35% (molar ratio). 8. The polyvinylamine polymer grafted with difluorobenzoic acid according to claim 5 or 6 is used as an antibacterial bactericide for fruits and vegetables. 9. the application method of the polyvinylamine macromolecular antibacterial bactericide containing difluorobenzene functional group as claimed in claim 8, is characterized in that: according to the difference of the number of colonies in the fruits and vegetables, the use concentration of the antibacterial bactericide is 1mg/ L～10mg/L.