Preparation method and application of novel ampholytic surfactant with thickening and synergistic effects

Abstract

The invention discloses a preparation method of a novel ampholytic surfactant with thickening and synergistic effects, which comprises the following steps: carrying out amidation reaction on N, N-dimethyl propane diamine and maleic anhydride, dehydrating and esterifying with alkyl alcohol or polyether alcohol, and sulfonating by using a sodium hydrogen sulfite aqueous solution to obtain the ampholytic surfactant. When the prepared ampholytic surfactant is applied to a pesticide aqueous solution formula, the viscosity of a solution is remarkably improved, and the thickening performance and the synergistic performance are enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method of a new type of amphoteric surfactant and its application in thickening and synergistic effect of pesticide aqueous solution. BACKGROUND

[0002] Surfactants are divided into ionic surfactants, non-ionic surfactants and amphoteric surfactants.

[0003] Amphoteric surfactants contain both anions and cations in the molecule. Due to their excellent alkali resistance, hard water resistance, permeability, low foam, low interfacial tension, low toxicity and other characteristics, they play an important role in agricultural production and are widely used in industrial production and daily life.

[0004] In the molecular structure of this type of surfactant, the cation is usually derived from quaternary ammonium salt, and the anion can be carboxylate, phosphate or sulfonate. For example, the commonly seen betaine series of amphoteric surfactants on the market are typical of this type of molecular structure.

[0005] In this molecular structure, on the one hand, the ratio of the hydrophilic group (such as quaternary ammonium nitrogen cation and carboxyl group) and the hydrophobic group (usually alkyl chain) is relatively balanced, so that the betaine tends to exist in a dissolved state in the aqueous solution rather than being strongly adsorbed on the interface. In contrast, some surfactants with longer hydrophobic chains or more hydrophobic groups can be more closely adsorbed on the surface of solids or the oil-water interface. On the other hand, due to the distribution of charged groups such as quaternary ammonium nitrogen cation and carboxyl group and the overall shape of the molecule, the interaction with the interface is affected, and the electrostatic repulsion and van der Waals force between molecules are relatively balanced and weak. The formed micelles are not large enough and the number is limited, and it is difficult for the micelles to form an effective network structure to increase the viscosity of the solution, resulting in insignificant thickening effect on the solution.

[0006] To this end, the present application studies a preparation method of a new type of amphoteric surfactant for improving the thickening and synergistic effect and its application. SUMMARY

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions: A preparation method of a new type of amphoteric surfactant, comprising the following steps: S1 adding a reaction medium and N,N'-dimethylpropylene diamine into a reactor, placing the reactor in an ice water bath, adding maleic anhydride in batches, controlling the feeding speed to keep the temperature in the reactor within the amidation temperature, and continuing to stir at room temperature to complete the amidation reaction after the feeding is completed; After the S2 amidation reaction is completed, the material after the S1 amidation reaction is mixed with an alkyl alcohol or a polyether alcohol and a catalyst is added, the temperature is raised to an esterification temperature and the esterification reaction is carried out under reduced pressure and heat preservation; S3, the material after the S2 esterification reaction is cooled to a sulfonation temperature, normal pressure is restored, sodium bisulfite aqueous solution is added dropwise, and sulfonation reaction is carried out after heat preservation after dropwise addition is completed, and finally a amphoteric surfactant is obtained. The molar ratio of the N,N'-dimethylpropylenediamine to maleic anhydride is 1: (0.99-1), the molar ratio of the N,N'-dimethylpropylenediamine to the alkyl alcohol or the polyether alcohol is 1: (1-1.28), and the molar ratio of the N,N'-dimethylpropylenediamine to the sodium bisulfite is 1: (1.20-1.45).

[0008] Further, the alkyl alcohol is one of n-hexanol, isooctanol, n-decanol and lauryl alcohol, and the polyether alcohol is a fatty alcohol polyoxyethylene ether or a nonylphenol polyoxyethylene ether.

[0009] Further, in S1, the reaction medium is an inert solvent or an alkyl alcohol or a polyether alcohol.

[0010] Further, in S1, the amidation temperature is 0-25 DEG C, and the room temperature stirring time is 16 h.

[0011] Further, in S2, the esterification temperature is 80-120 DEG C, the vacuum degree under reduced pressure and heat preservation is 0.095 MPa, and the heat preservation time is 3 h.

[0012] Further, in S2, the catalyst is p-toluenesulfonic acid or sulfuric acid.

[0013] Further, in S3, the sulfonation temperature is 60-100 DEG C, the mass fraction of the sodium bisulfite in the aqueous solution is 6-10%, and the dropwise addition time is ≤3 h.

[0014] Further, in the above preparation method, first, N,N-dimethylpropylenediamine is reacted with maleic anhydride to generate an amide with a carboxyl group at one end, then dehydrating esterification is carried out with an alkyl alcohol or a polyether alcohol, and then sulfonation is carried out using sodium bisulfite aqueous solution, so that the amphoteric surfactant can be prepared, and the reaction process is as follows: That is, by the above preparation method, the amphoteric surfactant can be obtained, and the general structure formula is as follows: (Formula 1) In the formula, R is an alkyl alcohol group or a polyether alcohol group.

[0015] The application also provides that the amphoteric surfactant prepared by the above preparation method is used as a thickening agent in a pesticide aqueous solution, and the thickening effect of the amphoteric surfactant is 5-10%.

[0016] The application also provides the synergistic effect of the amphoteric surfactant prepared by the preparation method as a synergist in a pesticide aqueous solution.

[0017] In the amidation reaction, the nitrogen-containing amide structure is introduced, forming a nitrogen-carbon amphoteric ion structure part similar to the structure of betaine, which endows the surfactant with amphoteric characteristics. This structure also provides a positive center or a partially positive region for the molecule, so that the prepared amphoteric surfactant has cationic characteristics, which helps to form larger molecular aggregates, thereby increasing the viscosity of the solution. Moreover, the amide group has the ability to form hydrogen bonds, and the surfactant molecules can form a hydrogen bond network through the amide group. The formation of hydrogen bonds increases the intermolecular interaction force, so that the molecules are more easily aggregated together to form a more compact and ordered structure, thereby further improving the thickening effect of the solution. Moreover, the cationic part of the prepared surfactant can be closely combined with the surface of the adherend (such as a leaf) through electrostatic adsorption, thereby increasing the adhesion amount of the pesticide solution on the adherend, reducing the loss of the pesticide solution, allowing more pesticide solution active ingredients to act on the adherend, and improving the efficiency.

[0018] The ester group structure formed by the esterification reaction of the material after the amidation reaction with an alkyl alcohol or a polyether alcohol further constructs the hydrophilic-hydrophobic balance structure of the surfactant. The ester group structure can match the hydrophilic-hydrophobic characteristics of the adherend surface, so that the pesticide solution can form a stable adsorption layer on the adherend surface, improve the adhesion performance, and the hydrophobic part of the ester group structure can interact with the wax layer on the adherend surface, while the hydrophilic part can help the pesticide solution active ingredient molecules to pass through the hydrophilic channel on the adherend surface, promote penetration, accelerate the exertion of the drug effect, and improve the efficiency.

[0019] Finally, the sulfonate anion group is introduced, so that the molecule has both a nitrogen-containing cationic part and a sulfonate anion part, increasing the interaction between the surfactant molecules and water molecules, making the surfactant better dissolved and dispersed in the solution, forming a more stable micellar structure, thereby facilitating the uniform adhesion and penetration of the pesticide solution on the adherend.

[0020] The application has the following beneficial effects: 1. The amphoteric surfactant prepared by the present application is prepared by amidation reaction of N,N-dimethylpropylene diamine and maleic anhydride, then dehydrating esterification with alkyl alcohol or polyether alcohol, and then sulfonation with sodium bisulfite aqueous solution, so that the prepared new amphoteric surfactant introduces nitrogen-containing amide structure, nitrogen-carbon amphoteric ion structure, ester group structure and sulfonate anion group, the nitrogen-containing amide structure can form hydrogen bond, the nitrogen-carbon amphoteric ion structure produces dipole-dipole interaction and ion-dipole interaction, and there is electrostatic repulsion between the sulfonate anion groups, and the structural characteristics have unique hydrophilic-hydrophobic balance and charge distribution, which is beneficial to the formation of larger and more stable micelles or micellar structures of the molecules in the solution, increases the flow resistance of the solution, thereby significantly improves the viscosity of the solution, enhances the thickening performance, and also enhances the adhesion amount of the drug solution on the attached crops, reduces the loss of the drug solution, promotes the spreading and penetration of the drug solution, and ensures that the active ingredients of the pesticide can fully act on the attached crops, thereby improving the synergistic effect.

[0021] 2. The preparation method of the present application is relatively simple as a whole, the operation conditions are mild, the temperature requirement is not high, the requirement for equipment is low, the side reactions caused by high temperature can be avoided, and the selectivity of the reaction and the quality of the product are ensured. DETAILED DESCRIPTION

[0022] The present application is further illustrated by the following examples, which are intended to better understand the content and embody the essential characteristics of the present application, and therefore the examples should not be regarded as limiting the protection scope of the present application.

[0023] In the following examples, the reaction raw materials are all commercially available products, and the following fatty alcohol polyoxyethylene ether adopts AEO-3 which is a product of CAS 68131-39-5, AEO-5 which is a product of CAS 9064-14-6, and nonylphenol polyoxyethylene ether NP-4 which is a product of CAS 9016-45-9.

[0024] Example 1 Into a reaction bottle, 106.00 grams of fatty alcohol polyoxyethylene ether (AEO-3) and 34.00 grams of N,N'-dimethylpropylene diamine were sequentially added, the reaction bottle was placed in an ice water bath, 32.34 grams of maleic anhydride was added in batches, the feeding speed was controlled to make the temperature not exceed 15℃, after the feeding was completed, the reaction was continuously stirred at room temperature for 16 hours, then 2.58 grams of p-toluenesulfonic acid was added, the temperature was raised to 120℃, and the vacuum degree of 0.095 MPa was maintained for 3 hours, the reaction liquid was cooled to 60℃, and then the normal pressure was restored, a freshly prepared solution of 41.60 grams of sodium bisulfite and 420 grams of water was added dropwise within 3 hours, after the dropwise addition was completed, the reaction was continuously maintained for 1 hour, and then an amphoteric surfactant sample 1 was obtained.

[0025] Example 2 Into a reaction flask, 130.00 g of fatty alcohol polyoxyethylene ether (AEO-5) and 25.50 g of N,N'-dimethylpropylene diamine were sequentially added, the reaction flask was placed in an ice water bath, 32.34 g of maleic anhydride was added in batches, the temperature was controlled to be not more than 25°C by controlling the feeding speed, after the feeding was completed, the reaction was continuously stirred at room temperature for 16 hours, then 1.8 g of p-toluenesulfonic acid was added, the temperature was raised to 80°C, a vacuum degree of 0.095 MPa was maintained for 3 hours of reaction, the reaction liquid was cooled to 60°C, and then the normal pressure was restored, a freshly prepared solution of 37.70 g of sodium bisulfite and 450 g of water was added dropwise within 3 hours, after the dropwise addition was completed, the reaction was continuously maintained for 1 hour, and then a sample of amphoteric surfactant ② was obtained.

[0026] Example 3: Into a reaction flask, 87.78 g of nonylphenol polyoxyethylene ether (NP-4) and 25.50 g of N,N'-dimethylpropylene diamine were sequentially added, the reaction flask was placed in an ice water bath, 24.40 g of maleic anhydride was added in batches, the temperature was controlled to be not more than 15°C by controlling the feeding speed, after the feeding was completed, the reaction was continuously stirred at room temperature for 16 hours, then 2.20 g of p-toluenesulfonic acid was added, the temperature was raised to 120°C, a vacuum degree of 0.095 MPa was maintained for 3 hours of reaction, the reaction liquid was cooled to 60°C, and then the normal pressure was restored, a freshly prepared solution of 33.80 g of sodium bisulfite and 470 g of water was added dropwise within 3 hours, after the dropwise addition was completed, the reaction was continuously maintained for 1 hour, and then a sample of amphoteric surfactant ③ was obtained.

[0027] Example 4: Into a reaction flask, 93 g of lauryl alcohol and 51.00 g of N,N'-dimethylpropylene diamine were sequentially added, the reaction flask was placed in an ice water bath, 49.00 g of maleic anhydride was added in batches, the temperature was controlled to be not more than 15°C by controlling the feeding speed, after the feeding was completed, the reaction was continuously stirred at room temperature for 16 hours, then 3.20 g of sulfuric acid was added, the temperature was raised to 120°C, a vacuum degree of 0.095 MPa was maintained for 3 hours of reaction, the reaction liquid was cooled to 100°C, and then the normal pressure was restored, a freshly prepared solution of 33.80 g of sodium bisulfite and 470 g of water was added dropwise within 3 hours, after the dropwise addition was completed, the reaction was continuously maintained for 1 hour, and then a sample of amphoteric surfactant ④ was obtained.

[0028] Comparative Examples 1-6 were prepared under the operation and reaction conditions of Example 3, and the amounts of the reactants were changed to obtain samples of amphoteric surfactants ⑤-⑩.

[0029] The amounts of the reactants in Examples 1-4 and Comparative Examples 1-6 are as follows: Table 1 Reactants of examples and comparative examples Preparation Example N,N'-dimethylpropylenediamine Maleic anhydride Polyether alcohol Alkyl alcohol Sodium bisulfite Example 1 34.00 32.34 106.00 (fatty alcohol polyoxyethylene ether AEO-3) —— 41.60 (solution prepared with 652 g of water) Example 2 25.50 24.50 130.00 (fatty alcohol polyoxyethylene ether AEO-5) —— 37.70 (solution prepared with 450 g of water) Example 3 25.50 24.40 87.78 (nonylphenol polyoxyethylene ether NP-4) —— 33.80 (solution prepared with 470 g of water) Example 4 51.00 49.00 —— 93 (lauryl alcohol) 64 (solution prepared with 576 g of water) Comparative Example 1 25.5 22.05 87.78 (nonylphenol polyoxyethylene ether NP-4) —— 33.80 (solution prepared with 470 g of water) Comparative Example 2 25.5 26.95 87.78 (nonylphenol polyoxyethylene ether NP-4) —— 33.80 (solution prepared with 470 g of water) Comparative Example 3 25.5 24.40 69.30 (nonylphenol polyoxyethylene ether NP-4) —— 33.80 (solution prepared with 470 g of water) Comparative Example 4 25.5 24.40 101.64 (nonylphenol polyoxyethylene ether NP-4 —— 33.80 (solution prepared with 470 g of water) Comparative Example 5 25.5 24.40 87.78 (nonylphenol polyoxyethylene ether NP-4) —— 28.6 (solution prepared with 397 g of water) Comparative Example 6 25.5 24.40 87.78 (nonylphenol polyoxyethylene ether NP-4) 40.3 (solution prepared with 600 g of water) The 25% glufosinate ammonium mother liquor is added with the amphoteric surfactant sample 1 at a gradient of 1%-10%, the rest is supplemented with water, and a glufosinate ammonium water agent with a final content of 18.5% is configured.

[0030] Table 2 Thickening effect of amphoteric surfactants on glufosinate ammonium water agent at different addition amounts Addition amount 1% 3% 5% 6% 7% 8% 9% 10% Viscosity (millipascal second) Ineffective Ineffective 74 101 144 211 285 320 As shown in Table 2, when the amphoteric surfactant sample 1 is used as a thickening agent in the 25% glufosinate ammonium mother liquor alone, the thickening performance can be better embodied when the addition amount is greater than or equal to 5, and different viscosity formulations can be prepared by using different addition amounts, and the versatility is good.

[0031] The amphoteric surfactant samples 1-10 are added to the 25% glufosinate ammonium mother liquor at 10%, the rest is supplemented with water, and a glufosinate ammonium water agent with a final content of 18.5% is configured, 1) the viscosity of the glufosinate ammonium water agent is measured by a viscosity meter, 2) the same volume of glufosinate ammonium water agent is used for spraying, the weeding efficiency is counted according to GB / T 17980.47-2000 “Guidelines for Field Trials of Pesticides (I) Weeding Control in Root Vegetable Fields”, and the weeding efficiency is compared with that of the blank control water agent, and the improvement value of the weeding efficiency relative to the blank control water agent is recorded.

[0032] Table 3 Thickening effect and synergistic effect of amphoteric surfactants on glufosinate ammonium water agent at the same addition amount Preparation Example Viscosity Weeding efficiency Sample 1 320 62% Sample 2 325 47% Sample 3 312 75% Sample 4 318 59% Sample 5 202 33% Sample 6 285 40% Sample 7 231 32% Sample 8 272 26% Sample 9 198 18% Sample 10 217 29% As shown in Table 3, the examples 1-4 and the comparative examples 1-6 have certain thickening effect and synergistic effect on the glufosinate ammonium water agent, which meets the thickening needs of customers and improves the utilization rate of pesticides, so that the weeding efficiency is greatly improved, the viscosity value of the examples 1-4 is maintained at more than 300 at the same addition amount, is relatively stable, and has excellent synergistic effect.

[0033] The technical features of the above-described examples can be combined arbitrarily, and in order to make the description simple, all possible combinations of the technical features in the above-described examples are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the description.

[0034] The above-described examples only express several embodiments of the present application, the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for preparing a novel amphoteric surfactant, characterized in that: The steps include: S1. Add the reaction medium and N,N'-dimethylpropylenediamine to a reactor, place the reactor in an ice-water bath, and add maleic anhydride in batches. Control the addition rate so that the temperature in the reactor is within the amidation temperature. After the addition is completed, continue stirring at room temperature to complete the amidation reaction. After the amidation reaction in S2 is completed, the material after the amidation reaction in S1 is mixed with an alkyl alcohol or a polyether alcohol and a catalyst is added, and the temperature is raised to the esterification temperature and the reduced pressure is maintained to carry out the esterification reaction; S3: Cooling the material after the esterification reaction in S2 to the sulfonation temperature and then returning to normal pressure, adding a sodium bisulfite aqueous solution dropwise, and keeping the temperature after the addition is complete to carry out a sulfonation reaction, thereby finally obtaining an amphoteric surfactant; The molar ratio of the above-mentioned N,N'-dimethylpropylenediamine to maleic anhydride is: 1:(0.99~1), the molar ratio of N,N'-dimethylpropylenediamine to alkyl alcohol or polyether alcohol is: 1:(1~1.28), and the molar ratio of N,N'-dimethylpropylenediamine to sodium bisulfite is 1:(1.20~1.45).

2. The preparation method according to claim 1, characterized in that The alkyl alcohol is one of n-hexanol, isooctyl alcohol, n-decanol and lauryl alcohol, and the polyether alcohol is fatty alcohol polyoxyethylene ether or nonylphenol polyoxyethylene ether.

3. The preparation method according to claim 1, characterized in that In S1, the reaction medium is an inert solvent or an alkyl alcohol or a polyether alcohol.

4. The preparation method according to claim 1, characterized in that The amidation temperature in S1 was 0°C~25°C, and the stirring time at room temperature was 16 h.

5. The preparation method according to claim 1, characterized in that The esterification temperature in S2 is 80-120°C, the vacuum degree of the reduced pressure insulation is 0.095 MPa, and the insulation time is 3 hours.

6. The preparation method according to claim 1, characterized in that The catalyst in S2 is p-toluenesulfonic acid or sulfuric acid.

7. The preparation method according to claim 1, characterized in that The sulfonation temperature in S3 is 60-100 degrees, the mass fraction of the sodium bisulfite in the aqueous solution is 6%-10%, and the dropwise addition time is ≤3h.

8. An amphoteric surfactant, characterized in that The amphoteric surfactant prepared according to the preparation method according to claims 1-7 has the following general structural formula: (Formula 1) Wherein, R is an alkyl alcohol group or a polyether alcohol group.

9. The amphoteric surfactant according to claim 8, characterized in that The amphoteric surfactant is used as a thickener in pesticide aqueous solution, and the addition amount of the amphoteric surfactant is 5%-10%.

10. The amphoteric surfactant according to claim 8, characterized in that Used in pesticide aqueous solution as a synergist.

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