Acid and alkali resistant organosilicon surfactant, and preparation method and application thereof

Abstract

The invention discloses an acid and alkali resistant organosilicon surfactant and a preparation method and application thereof, and in the acid and alkali resistant organosilicon surfactant, polyethylene glycol (PEG) is matched with dimethyl siloxane (DMSO), so that necessary hydrophilicity and hydrophobicity balance in surfactant molecules is provided. The polyethylene glycol is beneficial to improving the solubility and water solubility of the surfactant, and the dimethyl siloxane enhances the stability of the solution and provides good surface activity, so that the pesticide solution can uniformly cover the surfaces of leaves in the spraying process, and the permeation effect of the pesticide is improved; the addition of the hydrogen fluoride acid plays a role in acidic catalysis in the synthesis process, and the use of the lactate solvent further optimizes the uniformity and solubility of the reaction solution. The lactate solvent improves the stability of the system, ensures that all the components can be effectively mixed, and improves the acid and alkali resistance of the pesticide solution in different pH environments.

Description

Technical Field

[0001] The invention belongs to the field of organic silicon surfactant, and specifically relates to an acid- and alkali-resistant organic silicon surfactant and a preparation method and application thereof. Background Art

[0002] In agricultural production, pesticides are widely used in agriculture as an important factor in increasing crop yields, preventing and controlling pests and pathogens. The application of pesticides not only depends on the concentration of its active ingredients, but is also affected by the stability, adhesion and permeability of the solution. In traditional pesticide solutions, surfactants, as an important auxiliary ingredient, are mainly used to improve the dispersibility, solubility, permeability and other functions of pesticides. However, existing surfactants usually show poor stability in strong acid or strong alkaline environments, especially pesticide solutions are prone to stratification, precipitation or inactivation under different soil pH values, weather changes and storage conditions, resulting in unstable pesticide effects and low efficiency.

[0003] Currently, many pesticide solutions have poor stability and are prone to precipitation and stratification when exposed to acidic or alkaline environments. For example, although herbicides such as glyphosate work well under neutral conditions, their active ingredients will degrade under acidic or alkaline conditions, resulting in a significant decrease in the weed control effect. In addition, most existing pesticide surfactants are only effective in neutral environments and have limited effects in highly acidic or alkaline environments.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, provide an acid- and alkali-resistant organosilicon surfactant and a preparation method and application thereof, and solve the problems raised in the above-mentioned background technology.

[0006] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0007] A method for preparing an acid- and alkali-resistant organosilicon surfactant comprises the following steps:

[0008] S1: Prepare the organosilicon source, using trimethylchlorosilane (C6H 18 Cl3Si), as the basic raw material for the reaction; fluoroalkyl groups and quaternary ammonium salt groups

[0009] S2: mixing the trimethylsilyl chloride described in step S1 with polyethylene glycol (PEG), dimethylsiloxane (DMSO) and a fluoroalkyl group or a quaternary ammonium salt group, and adding the mixture into a reactor for reaction to form a siloxane structure;

[0010] S3: heating the reaction system of step S2 to 100° C. by microwave heating, and the reaction lasts for 2 hours to promote the reaction between the surfactant group and the silicon source;

[0011] S4: adding hydrofluoric acid (HF) as an acidic catalyst to the reaction system of step S3 to adjust the acidity of the reaction system and promote the hydrolysis reaction of trimethylchlorosilane;

[0012] S5: adding a lactate solvent to the reaction system of step S4 to promote the dissolution of the reactants and improve the uniformity of the system;

[0013] S6: After the reaction is completed, the residual hydrofluoric acid and other reaction impurities are removed by washing with distilled water;

[0014] S7: Performing solvent extraction using dichloromethane to remove insoluble matter and solvent impurities, and purifying the resulting organosilicon surfactant.

[0015] Optionally, the mass fraction of the trimethylchlorosilane is 90-110 parts.

[0016] Optionally, the molecular weight of the polyethylene glycol is 1000, and the weight fraction is 25-35 parts.

[0017] Optionally, the molecular weight of the dimethylsiloxane is 500, and the mass fraction is 40-60 parts.

[0018] Optionally, the mass fraction of the fluoroalkyl group or the quaternary ammonium salt group is 4-6 parts.

[0019] Optionally, the mass concentration of the hydrofluoric acid is 0.5%, and the amount used is 0.05%-0.15% of the total mass of all reactants in the reaction system.

[0020] Optionally, the mass fraction of the lactate solvent is 8%-12% of the total reactants.

[0021] Optionally, the dichloromethane is used for solvent extraction to remove insoluble matter and impurities, and the purity of the obtained organosilicon surfactant reaches 90%-98%.

[0022] In a second aspect, the present invention provides an acid- and alkali-resistant organosilicon surfactant, which is prepared by the above-mentioned preparation method.

[0023] In a third aspect, the present invention provides the use of the above-mentioned acid- and alkali-resistant organosilicon surfactant in pesticides.

[0024] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art. Of course, any product implementing the present invention does not necessarily need to achieve all the advantages described below at the same time:

[0025] In the present invention, the combination of polyethylene glycol (PEG) and dimethylsiloxane (DMSO) provides the necessary hydrophilicity and hydrophobicity balance in the surfactant molecule. Polyethylene glycol helps to improve the solubility and water solubility of the surfactant, while dimethylsiloxane enhances the stability of the solution and provides good surface activity, so that the pesticide solution can evenly cover the leaf surface during the spraying process, improving the penetration effect of the pesticide. In addition, the addition of hydrofluoric acid plays an acidic catalytic role in the synthesis process, and the use of lactic acid ester solvent further optimizes the uniformity and solubility of the reaction solution. Lactic acid ester solvent improves the stability of the system, ensures that the components can be effectively mixed, and improves the acid and alkali resistance of the pesticide solution under different pH environments.

[0026] The specific implementation modes of the present invention are described in further detail below. DETAILED DESCRIPTION

[0027] The present invention will now be described in further detail.

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0029] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the scope.

[0030] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0031] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0032] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0033] In this embodiment, a method for preparing an acid- and alkali-resistant organosilicon surfactant is provided, comprising the following steps:

[0034] S1: Prepare the organosilicon source and select trimethylchlorosilane (C6H18Cl3Si) as the basic raw material for the reaction; fluoroalkyl groups and quaternary ammonium salt groups

[0035] S2: mixing the trimethylsilyl chloride described in step S1 with polyethylene glycol (PEG), dimethylsiloxane (DMSO) and a fluoroalkyl group or a quaternary ammonium salt group, and adding the mixture into a reactor for reaction to form a siloxane structure;

[0036] S3: heating the reaction system of step S2 to 100° C. by microwave heating, and the reaction lasts for 2 hours to promote the reaction between the surfactant group and the silicon source;

[0037] S4: adding hydrofluoric acid (HF) as an acidic catalyst to the reaction system of step S3 to adjust the acidity of the reaction system and promote the hydrolysis reaction of trimethylchlorosilane;

[0038] S5: adding a lactate solvent to the reaction system of step S4 to promote the dissolution of the reactants and improve the uniformity of the system;

[0039] S6: After the reaction is completed, the residual hydrofluoric acid and other reaction impurities are removed by washing with distilled water;

[0040] S7: Performing solvent extraction using dichloromethane to remove insoluble matter and solvent impurities, and purifying the resulting organosilicon surfactant.

[0041] In this embodiment, the mass fraction of trimethylchlorosilane is 90-110 parts.

[0042] In this embodiment, the molecular weight of the polyethylene glycol is 1000, and the mass fraction is 25-35 parts.

[0043] In this embodiment, the molecular weight of the dimethylsiloxane is 500, and the mass fraction is 40-60 parts.

[0044] In this embodiment, the mass fraction of the fluoroalkyl group or the quaternary ammonium salt group is 4-6 parts.

[0045] In this embodiment, the mass concentration of the hydrofluoric acid is 0.5%, and the amount used is 0.05%-0.15% of the total mass of all reactants in the reaction system.

[0046] It should be noted that all raw materials in the examples of the present invention were obtained through commercial sources.

[0047] Embodiment 1: In this embodiment, a method for preparing an acid-base resistant organosilicon surfactant is provided, comprising the following steps:

[0048] Step S1: First, 100 parts of trimethylsilyl chloride are taken as the basic raw material for the reaction and added into a reactor.

[0049] Step S2: 30 parts of polyethylene glycol (PEG, molecular weight 1000), 50 parts of dimethylsiloxane (DMSO, molecular weight 500) and 5 parts of fluoroalkyl groups (fluorinated alkyl groups or quaternary ammonium salt groups) are added to the trimethylchlorosilane in step 1 and mixed. The mixture is added to a reactor and reacted to form a siloxane structure.

[0050] Step S3: using a microwave heating device, the reaction system is heated to 100° C., and the reaction duration is 2 hours. During the heating process, microwave heating increases the reaction rate, so that the reaction between the surfactant group and the silicon source is more complete.

[0051] Step S4: Add 0.5% mass concentration of hydrofluoric acid (HF) to the reaction system in step 3, and the amount used is 0.1% of the total mass of all reactants in the reaction system. Hydrofluoric acid is used as an acidic catalyst to adjust the acidity of the reaction system and promote the hydrolysis reaction of trimethylchlorosilane.

[0052] Step S5: Continue to add lactate solvent to the reaction system, the mass fraction of lactate solvent is 10% of the total mass of reactants. This solvent is used to promote the dissolution of reactants and improve the uniformity of the system.

[0053] Step S6: After the reaction is completed, the reaction system is washed with distilled water, and the washing is repeated 3 times to remove residual hydrofluoric acid and other reaction impurities.

[0054] Step S7: Use dichloromethane to perform solvent extraction to remove insoluble matter and solvent impurities, and finally obtain an organosilicon surfactant with a purity of more than 95%

[0055] Embodiment 2: In this embodiment, a method for preparing an acid-base resistant organosilicon surfactant is provided, comprising the following steps:

[0056] Step S1: 110 parts of trimethylsilyl chloride are added into a reactor as a basic raw material for the reaction.

[0057] Step S2: 28 parts of polyethylene glycol (PEG, molecular weight 1000), 45 parts of dimethylsiloxane (DMSO, molecular weight 500) and 4 parts of fluoroalkyl groups (fluorinated alkyl groups or quaternary ammonium salt groups) are added into a reactor, mixed and reacted to form a siloxane structure.

[0058] Step S3: Use a microwave heating device to heat the reaction system to 100° C. and maintain the reaction for 2 hours to accelerate the reaction process and ensure complete reaction.

[0059] Step S4: Add 0.5% concentration of hydrofluoric acid (HF) to the reaction system, the amount used being 0.1% of the total mass of all reactants in the reaction system. Hydrofluoric acid acts as a catalyst to adjust the acidity of the reaction and promote the hydrolysis reaction of trimethylchlorosilane.

[0060] Step S5: Add lactate solvent to the reaction system, the mass fraction of which is 9% of the total reactants. This solvent helps to improve the uniformity of the solution and enhance the solubility of the reactants.

[0061] Step S6: After the reaction is completed, the reaction system is washed with distilled water, and the washing is repeated 3 times to remove the hydrofluoric acid and other impurities in the reaction.

[0062] Step S7: Finally, dichloromethane is used for solvent extraction to remove insoluble matter and impurities, and the purity of the obtained organosilicon surfactant reaches more than 96%

[0063] Embodiment 3: In this embodiment, a method for preparing an acid-base resistant organosilicon surfactant is provided, comprising the following steps:

[0064] Step S1: 100 parts of trimethylsilyl chloride (C6H 18 Cl3Si) is added into the reactor as the basic raw material for the reaction.

[0065] Step S2: Add 35 parts of polyethylene glycol (PEG, molecular weight 1000), 55 parts of dimethylsiloxane (DMSO, molecular weight 500) and 5 parts of fluoroalkyl groups to the trimethylsilyl chloride in step 1. Mix and add to a reactor for reaction to form a siloxane structure.

[0066] Step S3: Use a microwave heating device to heat the reaction system to 100° C. and maintain the temperature for 2 hours. Microwave heating can increase the reaction rate and ensure that the reaction proceeds fully.

[0067] Step S4: Add 0.5% concentration of hydrofluoric acid (HF) to the reaction system, the amount of hydrofluoric acid used is 0.1% of the total mass of all reactants in the reaction system. This step is used to adjust the acidity of the reaction system and promote the hydrolysis reaction of trimethylchlorosilane.

[0068] Step S5: Add lactate solvent to the reaction system, the mass fraction of which is 10% of the total reactant mass. This solvent helps to improve the uniformity of the system and ensures that the reaction proceeds smoothly.

[0069] Step S6: After the reaction is completed, wash with distilled water, repeat the washing three times to remove hydrofluoric acid and other reaction impurities.

[0070] Step S7: Finally, dichloromethane was used for solvent extraction to remove insoluble matter and impurities, and the obtained organosilicon surfactant was purified to a final purity of 97%.

[0071] Test example: Application of acid- and alkali-resistant surfactants in pesticides, the steps are as follows:

[0072] Step 1: First, add the glyphosate active ingredient (20 parts, mass) to the lactate solvent (50 parts, mass), and slowly mix under stirring until the glyphosate is completely dissolved. Then, the prepared solution is divided into 3 parts, and the acid-base resistant organosilicon surfactant (2 parts, mass) prepared in Example 1-3 is added respectively, and stirring is continued to ensure that it is evenly dispersed in the solution, thereby improving the acid-base resistance of the solution. Then, a synergist (such as oleamide or other surfactants, 0.5 parts, mass) is added to increase permeability, and an appropriate amount of water (about 27.5 parts, mass) is added as needed to dilute the solution to the final target concentration. At this point, the pH value of the solution is adjusted to the range of 6.0-8.0 to ensure the stability of glyphosate and optimize the acid-base resistance of the pesticide solution.

[0073] Step 2: Add 1 part of acidic solution (0.1M H2SO4) to the pesticide solutions prepared in Examples 1-3 respectively. Then, keep the temperature of these solutions at 25°C in a constant temperature box and stir them continuously for 6 hours to simulate the stability changes under different acid-base environments. Use a pH meter to measure the pH changes of each solution, and record the pH values ​​before and after the reaction to evaluate the stability of acid-base resistant surfactants under different pH conditions. Observe whether the solution shows stratification, precipitation, etc. to further verify the effect of surfactants on pesticide solutions.

[0074] Step 3: Load the pesticide solution prepared in step 1 into the sprayer and adjust the spraying diameter of the sprayer to make the spray uniform and the spraying amount moderate. When spraying, ensure that the temperature is 25°C, the humidity is 50%-60%, and the wind speed is moderate. Spray the pesticide solution on the test plot by uniform spraying to ensure a wide coverage of the pesticide. Within 24 hours after spraying, observe the herbicidal effect of glyphosate and the acid-base resistant surfactant.

[0075] Table 1: Acid and alkali resistance test data of pesticide solutions on the adhesion and penetration of plant leaves, evaluating the performance and stability of pesticide solutions.

[0076]

[0077] Note: The change in pH value is based on the results of each solution reacting for 6 hours under constant temperature conditions. The changes in acid and base in the solution show that the acid- and base-resistant surfactant can maintain good stability under different pH environments.

[0078] Table 1 shows the pH changes of the pesticide solutions of different embodiments within 6 hours. From the data, the pH changes of Examples 1 and 2 are relatively stable, and the pH values ​​gradually decrease, showing good stability. This shows that both can still maintain high stability in an acidic environment and have strong acid and alkali resistance. Although the pH value of Example 3 is also decreasing, a slight stratification phenomenon occurs, indicating that its stability in an acidic environment is poor and its acid and alkali resistance may be reduced.

[0079] Delamination / precipitation: There was no delamination or precipitation in Example 1 and Example 2, indicating that their surfactants had good stability under acid-base conditions. However, there was slight delamination in Example 3, indicating that its stability was reduced.

[0080] Table 2: Pesticide solution spray application effect data

[0081] Experimental samples Glyphosate herbicidal effect 24 hours after spraying (%) Example 1 88 Example 2 85 Example 3 82

[0082] Note: The herbicidal effect is evaluated based on the inhibition rate of glyphosate on weeds, and the effect is expressed as a percentage. The adhesion and penetration effects of surfactants are evaluated by observing the pesticide residues on the leaves and the depth of pesticide penetration.

[0083] Table 2 shows the glyphosate herbicidal effects of different experimental samples. The herbicidal effects of all experimental samples are good, but the glyphosate herbicidal effect of Example 1 is 88%, which is better than other examples. This shows that the pesticide solution of Example 1 can better adhere to the weeds after spraying and penetrate into the inside of the leaves, thereby improving the herbicidal effect of glyphosate. The best performance in the herbicidal effect of glyphosate can improve the herbicidal effect, indicating that its surfactant has the strongest ability in increasing adhesion and permeability.

[0084] The solution has good stability, and although slight stratification occurs in an acidic environment, it performs better on plant leaves, indicating that its surfactant can improve the adhesion and penetration of pesticides, further enhancing the biological activity of pesticides.

[0085] The present invention is not limited to the above-mentioned embodiments. Anyone should be aware that any structural changes made under the enlightenment of the present invention, and any technical solutions that are the same or similar to the present invention, fall within the protection scope of the present invention. The technology, shape, and structural parts not described in detail in the present invention are all well-known technologies.

Claims

1. A method for preparing an acid- and alkali-resistant organosilicon surfactant, characterized in that: The following steps are involved: S1: Prepare the organosilicon source and select trimethylchlorosilane as the basic raw material for the reaction; S2: mixing the trimethylsilyl chloride described in step S1 with polyethylene glycol, dimethylsiloxane and a fluoroalkyl group or a quaternary ammonium salt group, and adding the mixture into a reactor for reaction to form a siloxane structure; S3: heating the reaction system of step S2 to 100° C. by microwave heating, and the reaction lasts for 2 hours to promote the reaction between the surfactant group and the silicon source; S4: adding hydrofluoric acid as an acidic catalyst to the reaction system of step S3 to adjust the acidity of the reaction system and promote the hydrolysis reaction of trimethylchlorosilane; S5: adding a lactate solvent to the reaction system of step S4 to promote the dissolution of the reactants and improve the uniformity of the system; S6: After the reaction is completed, the residual hydrofluoric acid and other reaction impurities are removed by washing with distilled water; S7: Performing solvent extraction using dichloromethane to remove insoluble matter and solvent impurities, and purifying the resulting organosilicon surfactant.

2. The method for preparing an acid- and alkali-resistant organosilicon surfactant according to claim 1, wherein the mass fraction of trimethylchlorosilane is 90-110 parts.

3. The method for preparing an acid- and alkali-resistant organosilicon surfactant according to claim 1, wherein the molecular weight of the polyethylene glycol is 1000 and the mass fraction is 25-35 parts.

4. The method according to claim 1, wherein the molecular weight of the dimethylsiloxane is 500 and the mass fraction is 40-60 parts.

5. The method for preparing an acid- and alkali-resistant organosilicon surfactant according to claim 1, wherein the mass fraction of the fluoroalkyl group or the quaternary ammonium salt group is 4-6 parts.

6. The method for preparing an acid- and alkali-resistant organosilicon surfactant according to claim 1, wherein the mass concentration of the hydrofluoric acid is 0.5%, and the amount used is 0.05%-0.15% of the total mass of all reactants in the reaction system.

7. The method for preparing an acid- and alkali-resistant organosilicon surfactant according to claim 1, wherein the mass fraction of the lactate solvent is 8%-12% of the total reactant mass.

8. The method for preparing an acid- and alkali-resistant organosilicon surfactant according to claim 1, wherein: The dichloromethane is used for solvent extraction to remove insoluble matter and impurities, and the purity of the obtained organic silicon surfactant reaches 90%-98%.

9. An acid- and alkali-resistant organosilicon surfactant, characterized in that: The method is prepared by the method according to any one of claims 1 to 8.

10. Use of the acid- and alkali-resistant organosilicon surfactant according to claim 9 in pesticides.

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