A high-performance organosilicon surfactant and its application in pesticides

Abstract

This invention discloses a high-performance organosilicon surfactant and its application in pesticides, belonging to the field of pesticide chemical technology. Using pentaerythritol as the core skeleton, isopropylidene pentaerythritol is prepared by protecting two adjacent hydroxyl groups. A polyether segment is grafted onto this segment to obtain a polyether graft intermediate, which is then deprotected to prepare deprotected polyether-grafted pentaerythritol. A cationic group containing a long alkyl chain is then grafted onto the deprotected hydroxyl group. Through cationic ring-opening polymerization and nucleophilic ring-opening etherification, a reinforced intermediate is obtained. Finally, under chloroplatinic acid catalysis, the silanium-hydrogen bond of heptamethyltrisiloxane undergoes a hydrosilylation reaction with the allyl double bond at the end of the reinforced intermediate to obtain the high-performance organosilicon surfactant. This surfactant synergistically exhibits excellent properties of rapid wetting, long-lasting retention, and erosion resistance.

Description

Technical Field

[0001] This invention belongs to the field of pesticide chemical technology, specifically relating to a high-performance organosilicon surfactant and its application in pesticides. Background Technology

[0002] Surfactants are amphiphilic molecules possessing both hydrophilic and hydrophobic groups. Their core function is to reduce interfacial tension and improve interfacial properties such as wetting, dispersion, and emulsification. They are widely used in chemical, agricultural, and daily chemical industries. Organosilicon surfactants, with siloxane chains as hydrophobic groups and polyethers as hydrophilic groups, have overcome the performance limitations of traditional fatty amine and alcohol surfactants due to their unique molecular structure design, and have become a core synergistic component in pesticide formulations.

[0003] The initial motivation for its development stemmed from the fact that traditional surfactants have limited effectiveness in reducing interfacial tension, making it difficult to form effective wetting on the waxy leaf surfaces of crops, resulting in insufficient pesticide coverage and low pesticide utilization. Furthermore, traditional products require high concentrations, which increases application costs and can easily cause environmental problems. Some products also have poor compatibility with pesticide technicals, which can easily lead to formulation stratification and precipitation, affecting the stability of efficacy. In contrast, organosilicon surfactants, with their low surface energy characteristics of siloxane chains, achieve superior wetting and spreading performance.

[0004] Chinese invention patent application CN109452268A discloses a surfactant and its preparation method for improving the interfacial performance of pesticide droplet dispersion. The method involves alkoxylation modification of the polyethyleneamine backbone and end-capping with fatty acid residues to synthesize a surfactant that combines cationic properties with excellent interfacial performance. This structure significantly increases the deposition of pesticide solution on the target and enhances the physical stability of the mixed pesticide solution by improving formulation compatibility. Simultaneously, the oil-soluble fatty acids it contains effectively reduce droplet evaporation, increase droplet size, and improve uniformity. Therefore, while improving pesticide utilization, it significantly reduces droplet drift, thereby reducing environmental pollution and resource waste.

[0005] However, the aforementioned patents are conventional improvements to the performance of surfactants, with limited synergistic effects, and cannot simultaneously and efficiently solve the problems of spreading, adhesion, and anti-evaporation. Summary of the Invention

[0006] The purpose of this invention is to provide a high-performance organosilicon surfactant and its application in pesticides. By using pentaerythritol as a multifunctional core framework, and through selective protection, epoxy ring-opening polymerization, acid-catalyzed deprotection, cationization modification, and hydrosilylation reaction, it specifically solves the problems of existing pesticide surfactants having single functions and difficulty in synergistic effects.

[0007] The objective of this invention can be achieved through the following technical solutions: A method for preparing a high-performance organosilicon surfactant includes the following steps: Step 1: Using pentaerythritol as the core, isopropylidene pentaerythritol is formed by selectively protecting two adjacent hydroxyl groups. Then, using the unprotected hydroxyl group as the initiation site, it reacts with allyl epoxy polyether through nucleophilic ring-opening etherification to obtain a polyether graft intermediate with allyl groups at the end. Step 2: The polyether graft intermediate is subjected to acid-catalyzed hydrolysis to remove the isopropylidene protecting group, resulting in deprotected polyether grafted pentaerythritol. Then, the deprotected hydroxyl group is reacted with a cationic compound containing a long alkyl chain through nucleophilic ring opening to obtain the reinforced intermediate. Step 3: Under the catalysis of chloroplatinic acid, the silane-hydrogen bonds of heptamethyltrisiloxane undergo a hydrosilylation reaction with the allyl double bonds at the end of the reinforced intermediate, which are derived from the polyether chain, to prepare a high-performance organosilicon surfactant.

[0008] Furthermore, the specific preparation process of isopropylidene pentaerythritol is as follows: Pentaerythritol and anhydrous N,N-dimethylformamide were added to a round-bottom flask and heated with stirring until completely dissolved. 2,2-Dimethoxypropane and a protic acid were slowly added, and the mixture was refluxed in an oil bath at 100-110°C for 3-5 days. The mixture was extracted with dichloromethane, and the concentrated organic phase was collected and purified by column chromatography to obtain isopropylidene pentaerythritol. The reaction process is shown below:

[0009] Furthermore, the ratio of pentaerythritol, anhydrous N,N-dimethylformamide, 2,2-dimethoxypropane, and protic acid is 54.6-74.8 g : 250-350 mL : 50-70 mL : 0.2-0.4 g.

[0010] Furthermore, the protic acid is either p-toluenesulfonic acid or camphorsulfonic acid.

[0011] Furthermore, the specific preparation process of the polyether grafting intermediate is as follows: The complex of isopropylidene pentaerythritol, anhydrous toluene, and boron trifluoride diethyl ether was added to a three-necked flask, nitrogen gas was introduced, and the temperature was raised to 80-90℃. Allyl epoxy polyether was added dropwise over a period of 30-40 minutes. After the addition was complete, the reaction was allowed to proceed for 4-5 hours. The reaction solution was then cooled to room temperature and transferred to a separatory funnel. The solution was washed with saturated sodium bicarbonate solution until neutral, and the organic phase was separated. The solution was washed 1-3 times with saturated brine. After drying with anhydrous magnesium sulfate, the solution was filtered and concentrated under reduced pressure to obtain the polyether grafting intermediate.

[0012] Furthermore, the ratio of isopropylidene pentaerythritol, anhydrous toluene, boron trifluoride diethyl ether complex, and allyl epoxy polyether is 4-6 g: 30-40 mL: 0.4-0.6 mL: 6-8 g.

[0013] Furthermore, the specific preparation process of deprotected polyether-grafted pentaerythritol is as follows: The polyether grafting intermediate and methanol were added to a round-bottom flask and stirred to dissolve. Concentrated hydrochloric acid was slowly added under ice bath conditions, and the mixture was magnetically stirred for 15-30 minutes. The ice bath was removed and the mixture was allowed to cool to room temperature. The mixture was then heated in an oil bath at 60-70°C for 3-4 hours. The mixture was washed with saturated sodium bicarbonate solution until neutral, extracted with dichloromethane, dried over anhydrous magnesium sulfate, and the organic phase was collected and concentrated. The organic phase was then purified by column chromatography to obtain deprotected polyether-grafted pentaerythritol.

[0014] Furthermore, the ratio of polyether grafting intermediate, methanol, and concentrated hydrochloric acid is 5.4-6.6g: 200-300mL: 5-8mL.

[0015] Furthermore, the specific preparation process of the enhanced intermediate is as follows: Deprotected polyether-grafted pentaerythritol, an alkaline catalyst, and deionized water were added to a three-necked flask and dissolved by sonication. Nitrogen gas was introduced, and the temperature was raised to 90-100°C. Dodecyl dimethyl glycidyl ammonium chloride was added dropwise over a period of 30-40 minutes. After the addition was complete, the reaction was allowed to proceed for 3-5 hours. After the reaction was completed, the mixture was neutralized to neutrality with a cation exchange resin, filtered, and the filtrate was distilled under reduced pressure to remove water and unreacted substances. The solution was then cooled to room temperature to obtain the reinforced intermediate.

[0016] Furthermore, the ratio of deprotected polyether-grafted pentaerythritol, alkaline catalyst, deionized water, and dodecyl dimethyl glycidyl chloride is 3.4-5.2 g : 0.1-0.3 g : 10-15 mL : 12-15 g.

[0017] Furthermore, the alkaline catalyst is any one of sodium hydroxide, potassium hydroxide, and sodium carbonate.

[0018] Furthermore, the specific preparation process of the high-performance organosilicon surfactant is as follows: Heptamethyltrisiloxane and isopropanol were added to a three-necked flask and stirred and heated to 80-90°C under a nitrogen atmosphere. Chloroplatinic acid catalyst was added dropwise for 30-40 min to activate the mixture. The temperature was then raised to 100-110°C and an enhanced intermediate was added dropwise over a period of 30-40 min. After the addition was complete, the mixture was reacted for 4-6 h. The solvent and unreacted products were distilled off under reduced pressure, and the mixture was cooled to room temperature to obtain a high-performance organosilicon surfactant.

[0019] Furthermore, the ratio of heptamethyltrisiloxane, isopropanol, chloroplatinic acid catalyst and reinforcing intermediate is 9.35-12.45 g: 5-8 g: 30-40 μL: 5.92-8.24 g.

[0020] This invention also provides the application of a high-performance organosilicon surfactant in pesticides.

[0021] The beneficial effects of this invention are: 1. This invention successfully prepared a high-performance organosilicon surfactant with precise structure and integrated functions through a synthesis strategy of "protection-grafting-deprotection-functionalization". This product integrates hydrophilic polyether chains, strongly adsorbent cationic-hydrophobic segments, and a super-spreading organosilicon framework, exhibiting excellent comprehensive performance. The organosilicon component enables rapid super-spreading of the pesticide solution on the leaves of hydrophobic plants, eliminating coverage dead zones. Through the synergistic effect of the cationic quaternary ammonium salt and long alkyl chains, it provides extremely strong leaf adhesion and excellent resistance to rain washout, eliminating the need for re-spraying after rain. Ultimately, this adjuvant achieves a comprehensive improvement in pesticide utilization, control effect, and operational efficiency in demanding scenarios such as aerial spraying, protection of high-value economic crops, and application in severe weather, making it an ideal synergist for achieving the goal of "reduced application and increased efficiency" in pesticides.

[0022] 2. The enhanced intermediate in this invention serves as a crucial link between the preceding and following phases. By precisely grafting dodecyl dimethyl glycidyl chloride onto the deprotected pentaerythritol backbone, a decisive leap in molecular function is achieved. While retaining the terminal allyl group for subsequent bonding, it successfully introduces a strong cationic quaternary ammonium salt head group and a long-chain dodecyl group, constructing a unique amphiphilic structure with a "one-end bihydrophilic polyether chain and one-end bicationic-hydrophobic chain." This structure not only endows the molecule with excellent emulsifying and dispersing properties and initial target adsorption, but its cationic groups can also firmly adhere to the plant surface through strong electrostatic interactions, helping to improve the pesticide's resistance to rain washout. Meanwhile, the long alkyl chain significantly enhances its affinity and penetration ability with the wax layer, making it an indispensable key to ultimately achieving synergistic effects of multiple properties such as super-spreading, strong adhesion, and anti-evaporation. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments in the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1: A high-performance organosilicon surfactant, prepared by the following steps: S1: Add 54.6 g pentaerythritol and 250 mL anhydrous N,N-dimethylformamide to a round-bottom flask, heat and stir until completely dissolved, slowly add 50 mL 2,2-dimethoxypropane and 0.2 g p-toluenesulfonic acid, heat under reflux in an oil bath at 100 °C for 3 days, monitor by TLC (ethyl acetate as the developing solvent, iodine fuming for color development) until the starting material spot basically disappears, extract with dichloromethane, collect the concentrated organic phase, separate by column chromatography with silica gel, eluent of ethyl acetate, Rf=0.5, to obtain isopropylidene pentaerythritol.

[0025] Pentaerythritol has four identical hydroxyl functional groups and a completely symmetrical spatial conformation. Under the catalysis of p-toluenesulfonic acid, 2,2-dimethoxypropane reacts with two adjacent hydroxyl groups of pentaerythritol, thereby undergoing isopropylidene protection.

[0026] S2: Add 4g of isopropylidene pentaerythritol, 30mL of anhydrous toluene, and 0.4mL of boron trifluoride diethyl ether complex to a three-necked flask, purge with nitrogen, heat to 80℃, and add 6g of allyl epoxy polyether dropwise over 30min. After the addition is complete, react for 4h. Once the reaction solution has cooled to room temperature, transfer it to a separatory funnel, wash with saturated sodium bicarbonate solution until neutral, separate the organic phase, wash once more with saturated brine, dry with anhydrous magnesium sulfate, filter, and concentrate under reduced pressure to obtain the polyether grafting intermediate.

[0027] Using isopropylidene pentaerythritol as a bifunctional initiator, allyl epoxy polyether monomers were grafted onto the pentaerythritol backbone via a cationic ring-opening polymerization mechanism of boron trifluoride diethyl ether complex under Lewis acid catalysis to obtain polyether grafting intermediates.

[0028] S3: Add 5.4 g of polyether grafting intermediate and 200 mL of methanol to a round-bottom flask, stir to dissolve, slowly add 5 mL of concentrated hydrochloric acid under ice bath conditions, stir magnetically for 15 min, remove the ice bath and let it cool to room temperature, heat in an oil bath at 60 °C for 3 h, monitor by TLC (dichloromethane:acetone = 6:1 as the developing solvent, iodine fuming for color development), the reactants react completely, add saturated sodium bicarbonate solution to neutralize the reaction, extract with dichloromethane, dry with anhydrous magnesium sulfate, collect and concentrate the organic phase, separate by column chromatography, eluent is dichloromethane:acetone = 6:1, Rf = 0.4, to obtain deprotected polyether grafted pentaerythritol.

[0029] Catalyzed by hydrochloric acid, the isopropylidene protecting group is selectively and efficiently removed through acid hydrolysis, thereby re-exposing the two hydroxyl groups on the pentaerythritol core, resulting in a polyether-grafted pentaerythritol derivative containing two free hydroxyl groups that can be used for subsequent functional group modification.

[0030] S4: Add 3.4g of deprotected polyether-grafted pentaerythritol, 0.1g of sodium hydroxide and 10mL of deionized water to a three-necked flask, sonicate to dissolve, introduce nitrogen gas, heat to 90℃, add 12g of dodecyl dimethyl glycidyl ammonium chloride dropwise over 30min, and react for 3h after the addition is complete. After the reaction is complete, adjust to neutral with cation exchange resin, filter, distill under reduced pressure to remove water and unreacted substances, and cool to room temperature to obtain the reinforced intermediate.

[0031] Under the catalysis of sodium hydroxide, the alkoxide anion grafted onto pentaerythritol by deprotected polyether undergoes nucleophilic ring-opening attack on the epoxy group of dodecyl dimethyl glycidyl ammonium chloride, thereby grafting the cationic-hydrophobic segment onto the molecule.

[0032] S5: Add 9.35g of heptamethyltrisiloxane and 5g of isopropanol to a three-necked flask. Under a nitrogen atmosphere, stir and heat to 80°C, add 30μL of chloroplatinic acid catalyst, activate for 30min, raise the temperature to 100°C, and add 5.92g of the reinforcing intermediate dropwise over a period of 30min. After the addition is complete, react for 4h. Distill off the solvent and unreacted products under reduced pressure, cool to room temperature, and obtain a high-performance organosilicon surfactant.

[0033] Under the catalysis of chloroplatinic acid, the silane-hydrogen bond of heptamethyltrisiloxane undergoes a hydrosilylation reaction with the allyl double bond at the end of the reinforcing intermediate. By forming Si-C bonds, surface-active organic segments are covalently grafted onto the organosilicon framework, thereby synthesizing a high-performance organosilicon surfactant with a complex structure and excellent performance.

[0034] Example 2: A high-performance organosilicon surfactant, prepared by the following steps: S1: Add 64.7 g pentaerythritol and 300 mL anhydrous N,N-dimethylformamide to a round-bottom flask, heat and stir until completely dissolved, slowly add 60 mL 2,2-dimethoxypropane and 0.3 g p-toluenesulfonic acid, heat under reflux in an oil bath at 105 °C for 4 days, monitor by TLC (ethyl acetate as the developing solvent, iodine fuming for color development), monitor until the starting material spot basically disappears, extract with dichloromethane, collect the concentrated organic phase, separate by column chromatography with silica gel, eluent ethyl acetate, Rf=0.5, to obtain isopropylidene pentaerythritol.

[0035] S2: Add 5g of isopropylidene pentaerythritol, 35mL of anhydrous toluene, and 0.5mL of boron trifluoride diethyl ether complex to a three-necked flask, purge with nitrogen, heat to 85℃, and add 7g of allyl epoxy polyether dropwise over a period of 35min. After the addition is complete, react for 4.5h. Once the reaction solution has cooled to room temperature, transfer it to a separatory funnel, wash with saturated sodium bicarbonate solution until neutral, separate the organic phase, wash twice more with saturated brine, dry with anhydrous magnesium sulfate, filter, and concentrate under reduced pressure to obtain the polyether grafting intermediate.

[0036] S3: Add 6.0 g of polyether grafting intermediate and 250 mL of methanol to a round-bottom flask, stir to dissolve, and slowly add 6.5 mL of concentrated hydrochloric acid under ice bath conditions. Stir magnetically for 22.5 min, remove the ice bath and let it cool to room temperature. Heat the mixture in an oil bath at 65 °C for 3.5 h. Monitor the reaction by TLC (using dichloromethane:acetone = 6:1 as the developing solvent and iodine fuming for color development). Once the reaction is complete, wash with saturated sodium bicarbonate solution until neutral, extract with dichloromethane, dry with anhydrous magnesium sulfate, collect and concentrate the organic phase, and separate by column chromatography with dichloromethane:acetone = 6:1 as the eluent and Rf = 0.45 to obtain deprotected polyether grafted pentaerythritol.

[0037] S4: Add 4.3g of deprotected polyether-grafted pentaerythritol, 0.2g of sodium hydroxide and 12.5mL of deionized water to a three-necked flask, sonicate to dissolve, purge with nitrogen, heat to 95℃, and add 13.5g of dodecyl dimethyl glycidyl ammonium chloride dropwise over 35min. After the addition is complete, react for 4h. After the reaction is complete, adjust to neutral with cation exchange resin, filter, and distill under reduced pressure to remove water and unreacted substances. Cool to room temperature to obtain the reinforced intermediate.

[0038] S5: Add 10.9 g of heptamethyltrisiloxane and 6.5 g of isopropanol to a three-necked flask, stir and heat to 85 °C under a nitrogen atmosphere, add 35 μL of chloroplatinic acid catalyst, activate for 35 min, raise the temperature to 105 °C, add 7.08 g of the reinforcing intermediate dropwise, control the addition time at 35 min, react for 5 h after the addition is complete, distill off the solvent and unreacted products under reduced pressure, cool to room temperature, and obtain a high-performance organosilicon surfactant.

[0039] Example 3: A high-performance organosilicon surfactant, prepared by the following steps: S1: Add 74.8 g pentaerythritol and 350 mL anhydrous N,N-dimethylformamide to a round-bottom flask, heat and stir until completely dissolved, slowly add 70 mL 2,2-dimethoxypropane and 0.4 g p-toluenesulfonic acid, heat under reflux in an oil bath at 110 °C for 5 days, monitor by TLC (ethyl acetate as the developing solvent, iodine fuming for color development), monitor until the starting material spot basically disappears, extract with dichloromethane, collect the concentrated organic phase, separate by column chromatography with silica gel, eluent ethyl acetate, Rf=0.6, to obtain isopropylidene pentaerythritol.

[0040] S2: Add 6g of isopropylidene pentaerythritol, 40mL of anhydrous toluene, and 0.6mL of boron trifluoride diethyl ether complex to a three-necked flask, purge with nitrogen, heat to 90℃, and add 8g of allyl epoxy polyether dropwise over a period of 40min. After the addition is complete, react for 5h. Once the reaction solution has cooled to room temperature, transfer it to a separatory funnel, wash with saturated sodium bicarbonate solution until neutral, separate the organic phase, wash three more times with saturated brine, dry with anhydrous magnesium sulfate, filter, and concentrate under reduced pressure to obtain the polyether grafting intermediate.

[0041] S3: Add 6.6 g of polyether grafting intermediate and 300 mL of methanol to a round-bottom flask, stir to dissolve, and slowly add 8 mL of concentrated hydrochloric acid under ice bath conditions. Stir magnetically for 30 min, remove the ice bath and let it cool to room temperature. Heat the mixture in an oil bath at 70 °C for 4 h and monitor the reaction by TLC (using dichloromethane:acetone = 6:1 as the developing solvent and iodine fuming for color development). The reactants were completely reacted. The mixture was washed with saturated sodium bicarbonate solution until neutral, extracted with dichloromethane, dried over anhydrous magnesium sulfate, and the organic phase was collected and concentrated. The organic phase was separated by column chromatography with dichloromethane:acetone = 6:1 as the eluent and Rf = 0.5 to obtain deprotected polyether grafted pentaerythritol.

[0042] S4: Add 5.2g of deprotected polyether-grafted pentaerythritol, 0.3g of sodium hydroxide and 15mL of deionized water to a three-necked flask, sonicate to dissolve, purge with nitrogen, heat to 100℃, add 15g of dodecyl dimethyl glycidyl ammonium chloride dropwise over 40min, and react for 5h after the addition is complete. After the reaction is complete, neutralize to neutral with cation exchange resin, filter, and distill the filtrate under reduced pressure to remove water and unreacted substances. Cool to room temperature to obtain the reinforced intermediate.

[0043] S5: 12.45 g of heptamethyltrisiloxane and 8 g of isopropanol were added to a three-necked flask. Under a nitrogen atmosphere, the mixture was stirred and heated to 90 °C. 40 μL of chloroplatinic acid catalyst was added dropwise, and the mixture was activated for 40 min. The temperature was then raised to 110 °C, and 8.24 g of the reinforcing intermediate was added dropwise over a period of 40 min. After the addition was complete, the mixture was reacted for 6 h. The solvent and unreacted products were distilled off under reduced pressure, and the mixture was cooled to room temperature to obtain a high-performance organosilicon surfactant.

[0044] Example 4: This example provides a method for preparing a high-performance organosilicon surfactant. The difference from Example 1 is that camphor sulfonic acid is used instead of p-toluene sulfonic acid in step S1 to prepare a high-performance organosilicon surfactant.

[0045] Example 5: This example provides a method for preparing a high-performance organosilicon surfactant. The difference from Example 1 is that potassium hydroxide or sodium carbonate is used instead of sodium hydroxide in step S4 to prepare a high-performance organosilicon surfactant.

[0046] In Examples 1-5, pentaerythritol was selected from Hubei Langbowan Biomedical Co., Ltd., brand name Langbowan; 2,2-dimethoxypropane was selected from Nanjing Reagent, CAS number 77-76-9; p-toluenesulfonic acid was selected from Langfang Qianyao Technology Co., Ltd., brand name Qianyao Technology; column chromatography silica gel was selected from Rizhao Kepu Nuo New Materials Co., Ltd., CAS number 112926-00-8, particle size 0.075-0.048mm; boron trifluoride diethyl ether complex was selected from Jiangsu Bosite Chemical Technology Co., Ltd., CAS number 109-63-7; allyl epoxy polyether was selected from Hubei Xingyan New Materials Technology Co., Ltd., model KL-11; saturated sodium bicarbonate solution was selected from Guangzhou Hewei Pharmaceutical Technology Co., Ltd. The product is a CD433840-500ML, catalog number CD433840; dodecyl dimethyl glycidyl chloride: its synthesis method is prepared according to the method described in the reference (Mao Lajie. Synthesis and Application Research of Dodecyl Dimethyl Glycidyl Chloride [D]. Zhengzhou University, 2010.); the cation exchange resin is selected from Langfang Jinan Resin Co., Ltd., with a particle size of 0.315-1.25mm; heptamethyltrisiloxane is selected from Shandong Yuanjin New Materials Co., Ltd., brand name Shandong Yuanjin, CAS number 1873-88-7; chloroplatinic acid catalyst is selected from Hubei Xinghengye Technology Co., Ltd., CAS number 19583-77-8, metal content is 34.72%; the remaining raw materials are commercially available products.

[0047] Comparative Example 1: The difference from Example 1 is that steps S1, S4 and S5 are omitted, and isopropylidene pentaerythritol is replaced with pentaerythritol in step S2. The remaining steps remain unchanged, and a high-performance organosilicon surfactant is prepared.

[0048] Comparative Example 2: The difference from Example 1 is that the amount of dodecyl dimethyl glycidyl ammonium chloride added in step S4 is halved, while the other steps remain unchanged, and a high-performance organosilicon surfactant is prepared.

[0049] Comparative Example 3: The difference from Example 1 is that steps S1, S2, S3 and S4 are omitted, and in step S5 the reinforcing intermediate is replaced with allyl epoxy polyether, while the other steps remain unchanged, to prepare a high-performance organosilicon surfactant.

[0050] Application example: Add 1g of the high-performance organosilicon surfactant prepared in this invention to 10mL of commercially available 41% glyphosate isopropylamine salt solution, stir at 300rpm for 10min to form a uniform and transparent synergist concentrate; when applying the herbicide in the field, first add 500mL of tap water to the backpack sprayer, then add 3.2mL of the concentrate and make up to 16L of tap water, stir manually for 2min to obtain a uniformly distributed and stable herbicide working solution.

[0051] The high-performance organosilicon surfactants prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to the following performance tests. Contact angle test: Using a contact angle meter, drop 2 μL of the test solution onto the surface of a standard hydrophobic paraffin sheet, immediately photograph the droplet morphology and measure the angle between the droplet and the solid surface, and record the angle data; the smaller the contact angle, the better the wetting and spreading performance of the solution, and the easier it is to cover the leaf surface.

[0052] Equilibrium surface tension test: The surface tension of the surfactant aqueous solution is measured at 25℃ using a surface tension meter. The surface tension value at this point is the equilibrium surface tension. The lower the value, the stronger the surfactant's ability to reduce surface tension.

[0053] Evaporation inhibition test: Under constant temperature and humidity conditions, a quantitative amount of the test drug solution was dropped onto a weighed glass slide, and the initial mass was recorded. Subsequently, the mass was continuously weighed at set time points (10, 20, 30 min), and the evaporation rate at each time point was calculated (mass lost due to evaporation / initial mass × 100%). The lower the evaporation rate, the stronger the ability of the liquid film formed by the adjuvant to retain moisture, and the more effectively it can prolong the action time of the drug solution.

[0054] Rain erosion resistance test: Referring to GB / T 35656-2017 "Method for Determination of Pesticide Deposition Rate", a glass slide sprayed with a certain amount of pesticide solution was air-dried under set conditions and then placed under an artificial simulated rainfall device for erosion at 20 mm / h and 10 min. The rain erosion resistance rate (amount after erosion / amount before erosion × 100%) was calculated by comparing the content of effective ingredients or the total mass of sediment on the target before and after erosion. The higher the erosion rate, the better the performance of the adjuvant in improving the adhesion of the pesticide solution.

[0055] The results are shown in Table 1: Table 1 Performance Test Results of High-Performance Organosilicon Surfactants

[0056] As can be seen from Table 1, the high-performance organosilicon surfactants prepared in Examples 1-5 are significantly superior to those in Comparative Examples 1-3. The surfactants in these examples use pentaerythritol as a symmetrical backbone, achieve hydrophilicity and spreading through the grafting of polyether chains, enhance adsorption on plant surfaces through the introduction of cationic-hydrophobic segments, and significantly reduce surface tension and inhibit evaporation through the bonding of the organosilicon backbone. They synergistically exert excellent properties of rapid wetting, long-lasting retention and anti-erosion, achieving a performance breakthrough in pesticide enhancement applications.

[0057] The increased evaporation rate and decreased rain erosion resistance of the pesticide in Comparative Example 1 may be due to the direct use of pentaerythritol, skipping the protection and deprotection steps and failing to perform cationic grafting. This results in the complete absence of the key cationic-hydrophobic segment in the molecule, and may have formed a non-selective polyether-linked branched structure. In terms of wetting and spreading, the lack of cationic groups in the molecule to initially and effectively adsorb the negative charge on the plant surface prevents the pesticide droplets from spreading quickly, leading to an increased contact angle and decreased wettability. In terms of adhesion persistence, due to the loss of electrostatic anchoring between the cationic groups and the leaf surface, the binding force between the pesticide and the leaf surface relies entirely on weak interactions such as van der Waals forces, making it extremely easy to detach under rain erosion. As a result, the rain erosion resistance deteriorates sharply, and the pesticide residue after simulated rainfall is far lower than in the example.

[0058] The increased contact angle and equilibrium surface tension in Comparative Example 2 may be due to halving the amount of dodecyl dimethyl glycidyl chloride added, which directly leads to insufficient grafting of cationic-hydrophobic segments in the final molecule, thus disrupting the perfect bilateral symmetry structure in the example. In terms of interfacial behavior, the reduced cationic-hydrophobic segments weaken the efficiency of close packing and adsorption site density of molecules at gas-liquid and liquid-solid interfaces, resulting in increased equilibrium surface tension and a decrease in wetting and spreading ability (contact angle) on hydrophobic surfaces. In terms of rain erosion resistance, due to the halving of adsorption sites, the strong adhesion of the molecule to the leaf surface through electrostatic interaction is not as good as in the example. Therefore, although the pesticide residue is better than that in Comparative Example 1, it is still significantly lower than that in the example with complete bilateral grafting, demonstrating the positive correlation between the number of cationic segments and the final performance.

[0059] In Comparative Example 3, the significantly increased contact angle, equilibrium surface tension, and reagent evaporation rate, along with a marked decrease in rain erosion resistance, are likely due to the fact that only the allyl epoxy polyether is linked to the organosilicon framework, resulting in the complete absence of the pentaerythritol symmetrical framework and cationic-hydrophobic segments. This leads to comprehensive performance disadvantages. In terms of wetting and reducing surface tension, the lack of multi-anchor support provided by pentaerythritol and adsorption drive from cationic groups results in insufficient arrangement efficiency and stability of the single polyether-organosilicon structure at the interface, leading to the largest contact angle and the highest equilibrium surface tension. In terms of retention and anti-evaporation, the missing cationic segments render it almost incapable of resisting rain erosion, and the simple molecular structure also fails to form an effective evaporation-inhibiting film, resulting in the highest evaporation rate.

[0060] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A high-performance organosilicon surfactant, characterized in that, Prepared by the following method: Step 1: Using pentaerythritol as the core, isopropylidene pentaerythritol is formed by selectively protecting two adjacent hydroxyl groups. Then, using the unprotected hydroxyl group as the initiation site, it reacts with allyl epoxy polyether through nucleophilic ring-opening etherification to obtain a polyether graft intermediate with allyl groups at the end. Step 2: The polyether graft intermediate is subjected to acid-catalyzed hydrolysis to remove the isopropylidene protecting group, resulting in deprotected polyether grafted pentaerythritol. Then, the deprotected hydroxyl group is reacted with a cationic compound containing a long alkyl chain through nucleophilic ring opening to obtain the reinforced intermediate. Step 3: Under the catalysis of chloroplatinic acid, the silane-hydrogen bonds of heptamethyltrisiloxane undergo a hydrosilylation reaction with the allyl double bonds at the end of the reinforced intermediate, which are derived from the polyether chain, to prepare a high-performance organosilicon surfactant.

2. The high-performance organosilicon surfactant according to claim 1, characterized in that, The specific preparation process of the isopropylidene pentaerythritol is as follows: Pentaerythritol and anhydrous N,N-dimethylformamide were added to a round-bottom flask and heated and stirred until completely dissolved. 2,2-dimethoxypropane and protic acid were slowly added and heated under reflux in an oil bath at 100-110°C for 3-5 days. The mixture was extracted with dichloromethane, and the concentrated organic phase was collected and purified by column chromatography to obtain isopropylidene pentaerythritol. The ratio of pentaerythritol, anhydrous N,N-dimethylformamide, 2,2-dimethoxypropane, and protic acid is 54.6-74.8 g : 250-350 mL : 50-70 mL : 0.2-0.4 g. The protic acid is either p-toluenesulfonic acid or camphorsulfonic acid.

3. The high-performance organosilicon surfactant according to claim 1, characterized in that, The specific preparation process of the polyether grafting intermediate is as follows: The complex of isopropylidene pentaerythritol, anhydrous toluene, and boron trifluoride diethyl ether was added to a three-necked flask, nitrogen gas was introduced, and the temperature was raised to 80-90℃. Allyl epoxy polyether was added dropwise over a period of 30-40 minutes. After the addition was complete, the reaction was allowed to proceed for 4-5 hours. The reaction solution was then cooled to room temperature and transferred to a separatory funnel. The solution was washed with saturated sodium bicarbonate solution until neutral, and the organic phase was separated. The solution was washed 1-3 times with saturated brine, dried with anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to obtain the polyether grafting intermediate.

4. The high-performance organosilicon surfactant according to claim 3, characterized in that, The ratio of isopropylidene pentaerythritol, anhydrous toluene, boron trifluoride diethyl ether complex, and allyl epoxy polyether is 4-6g: 30-40mL: 0.4-0.6mL: 6-8g.

5. The high-performance organosilicon surfactant according to claim 1, characterized in that, The specific preparation process of the deprotected polyether-grafted pentaerythritol is as follows: The polyether grafting intermediate and methanol were added to a round-bottom flask and stirred to dissolve. Concentrated hydrochloric acid was slowly added under ice bath conditions, and the mixture was magnetically stirred for 15-30 min. The ice bath was removed and the mixture was allowed to cool to room temperature. The mixture was then heated in an oil bath at 60-70℃ for 3-4 h. The mixture was washed with saturated sodium bicarbonate solution until neutral, extracted with dichloromethane, dried over anhydrous magnesium sulfate, and the organic phase was collected and concentrated. The organic phase was then separated and purified by column chromatography to obtain deprotected polyether grafted pentaerythritol. The ratio of the polyether grafting intermediate, methanol, and concentrated hydrochloric acid is 5.4-6.6g: 200-300mL: 5-8mL.

6. The high-performance organosilicon surfactant according to claim 1, characterized in that, The specific preparation process of the enhanced intermediate is as follows: Deprotected polyether-grafted pentaerythritol, an alkaline catalyst, and deionized water were added to a three-necked flask and dissolved by sonication. Nitrogen gas was introduced, and the temperature was raised to 90-100°C. Dodecyl dimethyl glycidyl ammonium chloride was added dropwise over a period of 30-40 minutes. After the addition was complete, the reaction was allowed to proceed for 3-5 hours. After the reaction was completed, the mixture was neutralized to neutrality with a cation exchange resin, filtered, and the filtrate was distilled under reduced pressure to remove water and unreacted substances. The solution was then cooled to room temperature to obtain the reinforced intermediate.

7. The high-performance organosilicon surfactant according to claim 6, characterized in that, The ratio of the deprotected polyether-grafted pentaerythritol, the alkaline catalyst, the deionized water, and the dodecyl dimethyl glycidyl chloride is 3.4-5.2 g : 0.1-0.3 g : 10-15 mL : 12-15 g; The alkaline catalyst is any one of sodium hydroxide, potassium hydroxide, and sodium carbonate.

8. The high-performance organosilicon surfactant according to claim 1, characterized in that, The specific preparation process of the high-performance organosilicon surfactant is as follows: Heptamethyltrisiloxane and isopropanol were added to a three-necked flask and stirred and heated to 80-90°C under a nitrogen atmosphere. Chloroplatinic acid catalyst was added dropwise for 30-40 min, and the temperature was raised to 100-110°C. An enhanced intermediate was added dropwise over a period of 30-40 min. After the addition was complete, the reaction was carried out for 4-6 h. The solvent and unreacted substances were removed by vacuum distillation, and the mixture was cooled to room temperature to obtain a high-performance organosilicon surfactant.

9. A high-performance organosilicon surfactant according to claim 8, characterized in that, The ratio of heptamethyltrisiloxane, isopropanol, chloroplatinic acid catalyst and reinforcing intermediate is 9.35-12.45 g: 5-8 g: 30-40 μL: 5.92-8.24 g.

10. The application of a high-performance organosilicon surfactant as described in any one of claims 1-9 in pesticides.

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