Amino acid surfactant, preparation method thereof and application of amino acid surfactant in preparation of termite insecticide

Abstract

The invention relates to an amino acid surfactant as well as a preparation method and application thereof in preparation of a termite insecticide, and belongs to the technical field of pest control. The N-acylamino acid is prepared by selecting specific fatty acid methyl ester and utilizing a mixture of alkaline earth metal oxide and phosphate as a catalyst. Specific N-acylamino acid prepared by a specific preparation method is used as an amino acid surfactant, and is mixed with a cosurfactant consisting of a betaine surfactant and a methyl taurine surfactant and water to obtain the insecticide for preventing and treating termites. The termite insecticide disclosed by the invention does not contain an organic solvent, a green amino acid surfactant is used as a killing repellent, and meanwhile, a green auxiliary surface active component with solubilizing and dispersing effects is added, so that the wettability of a system is enhanced; the material is safe, nontoxic and excellent in degradability; and the termite repellent is good in repelling and killing performance and is an alternative scheme for preventing termites.

Description

Technical Field

[0001] This invention relates to the field of pest control technology, and in particular to an amino acid surfactant, its preparation method, and its application in the preparation of termite insecticides. Background Technology

[0002] Termites are one of the world's five major pests. They mainly feed on cellulose such as wood, paper and plants, causing serious damage to buildings, crops and forest vegetation. The economic losses caused by termites worldwide amount to tens of billions of dollars every year.

[0003] Currently, termite control is mainly divided into three types: chemical control, physical control, and biological control. Among them, chemical control, which uses chemical agents to prevent or kill termite damage, is the most important and widespread method. The chemical reagents used in chemical control are diverse, and can be broadly classified into the following categories according to their chemical composition: First, inorganic salts, such as boric acid, arsenic reagents, potassium dichromate, and copper sulfate. These work by disrupting the termite's digestive system, metabolic function, or corroding its surface. Their core advantages are relatively low toxicity (except for some species), minimal environmental residue, readily available raw materials, and low cost. They are suitable for soaking, spraying, or mixing with wood. However, these agents generally have a short effective period, are highly water-soluble, and are easily washed away by humid environments, rendering them ineffective. They are only effective against termites that have come into contact with or ingested the termite, and cannot form a long-term protective barrier. Furthermore, some arsenic reagents are highly toxic, posing potential risks to human health and the ecological environment, and their use is currently restricted or prohibited in most areas. Second, organochlorine pesticides, traditional termite repellents such as chlordane and lindane, have long-lasting effects and broad protection, and were once widely used in soil treatment. However, these pesticides cause serious residual pollution and are highly toxic to the ecological environment and non-target organisms. Most countries have now restricted or banned their use. Third, pyrethroids, currently the mainstream pesticides, including bifenthrin and cypermethrin, have both contact and repellent effects, low toxicity, and good environmental compatibility. They are suitable for soil protection in construction and wood spraying. However, some varieties can easily lead to termite resistance, and long-term use alone will reduce their effectiveness. Fourth, organophosphates, such as chlorpyrifos and phoxim, have both contact and stomach poison effects, providing rapid termite control. They can be used for soil treatment and direct spraying of termite nests. However, some varieties have an irritating odor, a short-lasting effect, and some toxicity to aquatic organisms; therefore, precautions must be taken when using them. Fifth, neonicotinoids, represented by imidacloprid and thiamethoxam, are highly systemic and can be absorbed and transported through wood. Termites can be poisoned after feeding on them. They are suitable for wood protection and as baits. However, excessive use may affect pollinating insects such as bees, and their use has been restricted in some areas.

[0004] Current chemical control methods using chemical agents have the following drawbacks: ① Most are insoluble in water, requiring the addition of organic solvents, which increases formulation costs. Furthermore, the organic solvents used, such as toluene, acetone, and chloroform, are toxic and harmful to humans and the environment; ② Their toxicity poses a significant risk to human health and may have long-lasting effects on soil and water. Therefore, it is necessary to research and develop green, safe, and effective pesticides for termite control. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an amino acid surfactant, its preparation method, and its application in the preparation of termite insecticides.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for preparing an amino acid surfactant, comprising the following steps: S1. Mix fatty acid methyl ester with amino acid salt and catalyst, and reflux fully in a protective gas environment to obtain reactants; The fatty acid methyl ester is fatty acid methyl ester A or a mixture of fatty acid methyl ester A and fatty acid methyl ester B; fatty acid methyl ester A is an 18-26 carbon unsaturated straight-chain fatty acid methyl ester; fatty acid methyl ester B is a 10-20 carbon saturated branched-chain fatty acid methyl ester. The catalyst is a mixture of alkaline earth metal oxides and phosphates; S2. Cool the reactants obtained in step S1 to 40~60℃, add acid to acidify, separate into layers, take the supernatant and wash with warm water at 40~60℃, take the supernatant after washing and purify by vacuum distillation to remove excess water and residual methyl ester and other impurities, and obtain transparent liquid N-acyl amino acid, i.e. amino acid surfactant.

[0007] This invention utilizes specific fatty acid methyl esters, specifically those containing at least 18-26 carbon unsaturated straight-chain fatty acid methyl esters, and employs a mixture of alkaline earth metal oxides and phosphates as a catalyst to prepare N-acyl amino acids without the need for solvents. The preparation of N-acyl amino acids using this invention does not require complex or expensive equipment, making the operation simpler and less costly. Furthermore, the N-acyl amino acids prepared by this method exhibit better efficacy as termite insecticides, with higher toxicity and better repellency.

[0008] In a preferred embodiment of the preparation method described in this invention, in step S1, the fatty acid methyl ester is a mixture of fatty acid methyl ester A and fatty acid methyl ester B. Compared to using fatty acid methyl ester A alone, the N-acyl amino acid prepared by mixing fatty acid methyl ester A and fatty acid methyl ester B as a fatty acid methyl ester has better effect as a termite insecticide.

[0009] In a preferred embodiment of the preparation method of the present invention, the fatty acid methyl ester A includes at least one of methyl linoleate, methyl docosahexaenoic acid, methyl eicosapentaenoic acid, and methyl arachidonic acid; and the fatty acid methyl ester B includes at least one of methyl isotretinoate and methyl isostearate.

[0010] In a preferred embodiment of the preparation method described in this invention, fatty acid methyl ester A is methyl arachidonic acid, and fatty acid methyl ester B is methyl isostearate. This invention uses methyl arachidonic acid as fatty acid methyl ester A and methyl isostearate as fatty acid methyl ester B, resulting in N-acyl amino acids that have better efficacy as termite insecticides.

[0011] In a preferred embodiment of the preparation method of the present invention, the molar ratio of fatty acid methyl ester A to fatty acid methyl ester B in the mixture of fatty acid methyl ester A and fatty acid methyl ester B is 8~9:1~2.

[0012] In a preferred embodiment of the preparation method described in this invention, the molar ratio of fatty acid methyl ester A to fatty acid methyl ester B in the mixture is 9:1. When fatty acid methyl ester A and fatty acid methyl ester B are mixed in a molar ratio of 9:1, the resulting N-acyl amino acid exhibits better efficacy as a termite insecticide.

[0013] In a preferred embodiment of the preparation method of the present invention, in step S1, the molar ratio of the fatty acid methyl ester to the amino acid salt is 1:1 to 1.2.

[0014] In a preferred embodiment of the preparation method described in this invention, in step S1, the molar ratio of the fatty acid methyl ester to the amino acid salt is 1:1.1~1.2. The N-acyl amino acid prepared by the fatty acid methyl ester and amino acid salt at a molar ratio of 1:1.1~1.2 has a better effect as a termite insecticide.

[0015] In a preferred embodiment of the preparation method of the present invention, in step S1, the amino acid salt is a neutral amino acid salt.

[0016] In a preferred embodiment of the preparation method of the present invention, in step S1, the amino acid salt is glycine salt or alanine salt.

[0017] In a preferred embodiment of the preparation method of the present invention, in step S1, the amino acid salt is sodium glycine or sodium alanine.

[0018] In a preferred embodiment of the preparation method of the present invention, in step S1, the molar ratio of the fatty acid methyl ester to the alkaline earth metal oxide and phosphate in the catalyst is 1:0.08~0.21:0.010~0.032.

[0019] In a preferred embodiment of the preparation method described in this invention, in step S1, the molar ratio of the fatty acid methyl ester to the alkaline earth metal oxide and phosphate in the catalyst is 1:0.11~0.21:0.010~0.025. This molar ratio of fatty acid methyl ester to alkaline earth metal oxide and phosphate in the catalyst results in a better N-acyl amino acid as a termite insecticide.

[0020] In a preferred embodiment of the preparation method of the present invention, in step S1, the alkaline earth metal oxide includes magnesium oxide and calcium oxide; the phosphate is potassium phosphate.

[0021] In a preferred embodiment of the preparation method of the present invention, the protective gas in step S1 is nitrogen.

[0022] As a preferred embodiment of the preparation method of the present invention, in step S1, the conditions for the full reflux reaction are reflux reaction at 130~170℃ for 12h.

[0023] In a preferred embodiment of the preparation method described in this invention, in step S2, the pH value of the acidification is 1 to 2.

[0024] Secondly, the present invention provides an amino acid surfactant prepared using the above-described preparation method.

[0025] Thirdly, the present invention provides the application of the above-mentioned amino acid surfactant in the preparation of termite control products.

[0026] Fourthly, the present invention provides a termite insecticide comprising the following components by mass percentage: 10-20% of the above-mentioned amino acid surfactant, 1-5% of the co-surfactant, and the balance being water; wherein the co-surfactant is composed of a betaine-type surfactant and a methyl taurine-type surfactant.

[0027] This invention utilizes a specific N-acyl amino acid prepared by a specific method as an amino acid surfactant, which is mixed with a betaine-type surfactant and a methyl taurine-type surfactant (as co-surfactant) and water to obtain a termite control agent. The termite control agent of this invention is a water-based formulation, free of organic solvents, non-toxic, environmentally friendly, and possesses advantages such as good killing and wetting effects, making it a viable alternative to traditional methods. The green amino acid surfactant used in this invention acts as a killing and repellent agent, while adding green auxiliary surfactant components to solubilize and disperse the main components and enhance the wetting properties of the system; it is not only safe and non-toxic, but also contains green components, is a water-based formulation, free of organic solvents, and exhibits excellent degradability; it also possesses good repellent and killing properties. The termite control agent of this invention is simple to prepare; it is obtained by mixing the amino acid surfactant, co-surfactant, and water. It is also convenient to use; simply dilute the termite control agent with water (generally 10 times dilution) and spray it onto the protected area.

[0028] In a preferred embodiment of the termite insecticide of the present invention, the termite insecticide comprises the following components by weight percentage: 15-20% of the above-mentioned amino acid surfactant, 3-5% of co-surfactant, and the balance being water. Termite insecticides with this content range exhibit superior wetting properties, higher toxicity, and stronger repellency.

[0029] As a preferred embodiment of the termite exterminant of the present invention, the termite exterminant comprises the following components by mass percentage: 15% of the above-mentioned amino acid surfactant, 3% of the co-surfactant, and the balance being water.

[0030] In a preferred embodiment of the termite insecticide of the present invention, the mass ratio of betaine-type surfactant to methyl taurine-type surfactant in the co-surfactant is 1:0.2~0.5.

[0031] In a preferred embodiment of the termite insecticide of the present invention, the mass ratio of betaine-type surfactant to methyl taurine-type surfactant in the co-surfactant is 1:0.35-0.45.

[0032] In a preferred embodiment of the termite insecticide of the present invention, the mass ratio of betaine-type surfactant to methyl taurine-type surfactant in the co-surfactant is 1:0.4.

[0033] As a preferred embodiment of the termite insecticide of the present invention, the betaine-type surfactant includes at least one of alkyl betaine, alkylamidopropyl betaine, alkyl hydroxysulfonate betaine, and alkylamidopropyl hydroxysulfonate betaine; the methyl taurine surfactant is alkyl methyl taurate.

[0034] In a preferred embodiment of the termite insecticide of the present invention, the betaine-type surfactant is cocamidopropyl hydroxysulfonate betaine; and the methyl taurine surfactant is sodium cocoyl methyl taurate.

[0035] Fifthly, the present invention provides a method for preparing the above-mentioned termite insecticide, which is obtained by mixing amino acid surfactant, co-surfactant and water.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention prepares N-acyl amino acids by selecting specific fatty acid methyl esters, using methyl esters containing at least 18-26 carbon unsaturated straight-chain fatty acids as the fatty acid methyl esters, and employing a mixture of alkaline earth metal oxides and phosphates as a catalyst. The preparation of N-acyl amino acids in this invention does not require complex or expensive equipment, making the operation simpler and the cost lower. The specific N-acyl amino acids prepared using the specific method of this invention are used as amino acid surfactants, and mixed with water to form a co-surfactant composed of betaine-type surfactants and methyl taurine-type surfactants to obtain a termite control agent. The termite control agent of this invention is an aqueous formulation, free of organic solvents. This invention uses green amino acid surfactants as killing and repellent agents, and simultaneously adds green auxiliary surfactant components that act as solubilizers and dispersants to enhance the wetting properties of the system. It is not only safe and non-toxic with excellent degradability, but also has good repellent and killing properties, making it an alternative solution for termite control. Attached Figure Description

[0037] Figure 1 This is an appearance diagram of the N-acyl amino acid of Example 1 of the present invention; Figure 2 This is an appearance diagram of the N-acyl amino acid of Example 4 of the present invention; Figure 3 This is an appearance diagram of the termite exterminant of Embodiment 16 of the present invention. Detailed Implementation

[0038] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0039] Methyl linoleate: CAS No.: 112-63-0; Molecular formula: C 19 H 34 O2; Docosahexaenoic acid methyl ester: CAS No.: 301-01-9; Molecular formula: C 23 H 34 O2; Methyl eicosapride: CAS No.: 2734-47-6; Molecular Formula: C 21 H 32 O2; Methyl arachidonic acid: CAS No.: 2566-89-4; Molecular formula: C 21 H 34 O2; Methyl isotridecanoate: CAS number: NULL; Molecular formula: C 14 H 28 O2; Methyl isostearate: CAS No.: 5129-61-3; Molecular formula: C 19 H 38 O2; Sodium glycine: CAS number: 6000-44-8; Molecular formula: C2H4O2NNa; Sodium alanine: CAS number: Null; Molecular formula: C3H6O2NNa; Magnesium oxide: CAS number: 1309-48-4; Molecular formula: MgO; Potassium phosphate: CAS number: 7778-53-2; Molecular formula: K3PO4.

[0040] Unless otherwise specified, all other materials and reagents used in the examples are commercially available.

[0041] The fatty acid methyl ester of the present invention can be commercially available or synthesized by the following method: 1 mol of fatty acid is added to a reaction vessel, nitrogen is purged for 30 min to completely remove oxygen from the reaction vessel, and then the temperature is raised to 40-60°C while stirring. Subsequently, 4 mol (128.16 g) of methanol and 0.03 mol (3.02 g) of concentrated sulfuric acid are added and stirred continuously. Then the temperature is raised to 65-75°C, and the mixture is kept at this temperature and stirred under reflux for 2-4 h to allow the reaction to proceed fully. The reactants are cooled to below 40°C, deionized water is added, and the mixture is stirred thoroughly. After standing for 30 min, the layers are separated. The upper liquid is taken and washed 2-3 times with deionized water. The washed upper liquid is then distilled under reduced pressure to obtain the fatty acid methyl ester.

[0042] Example 1 An embodiment of the method for preparing N-acyl amino acids according to the present invention includes the following steps: S1. Mix 0.9 mol of methyl arachidonic acid and 0.1 mol of methyl isostearate with a mixed catalyst of 1.1 mol of sodium glycinate, 0.16 mol of magnesium oxide and 0.019 mol of potassium phosphate, and reflux at 140 °C for 12 h under nitrogen protection to obtain the reactant. S2. Cool the reactants obtained in step S1 to 60°C, add dilute hydrochloric acid to acidify the reactant system to pH 1-2, separate the layers, take the supernatant, wash twice with 60°C warm water, purify the supernatant by vacuum distillation after washing to remove excess water, residual methyl ester and other impurities, and obtain a transparent liquid, which is N-acyl amino acid.

[0043] Example 2-15 Fourteen embodiments of the method for preparing N-acyl amino acids of the present invention, wherein the method for preparing N-acyl amino acids in Examples 2-15 includes the following steps: S1. Mix the mixture of fatty acid methyl ester A and fatty acid methyl ester B with a mixed catalyst of amino acid salt, magnesium oxide and potassium phosphate, and reflux at 130~170℃ for 12h under nitrogen protection to obtain the reactant. S2. Cool the reactants obtained in step S1 to 40~60℃, add dilute hydrochloric acid to acidify the reactant system to pH 1~2, separate the layers, take the supernatant and wash it twice with warm water at 40~60℃, take the supernatant after washing and purify it by vacuum distillation to remove excess water and residual methyl ester and other impurities, and obtain a transparent liquid, which is N-acyl amino acid.

[0044] Table 1 shows the material or content information of fatty acid methyl ester A, fatty acid methyl ester B, amino acid salt, magnesium oxide, and potassium phosphate in step S1 of the preparation methods of N-acyl amino acids in Examples 1-15. Table 1 The N-acyl amino acid of this invention is a brown to light yellow transparent liquid. The appearance of the N-acyl amino acid in Example 1 is shown in the figure below. Figure 1 As shown, the appearance of the N-acyl amino acid in Example 4 is as follows. Figure 2 As shown. The N-acyl amino acid in Example 1 was a light yellow transparent liquid; the N-acyl amino acid in Example 4 was a brown transparent liquid.

[0045] Example 16 One embodiment of the termite insecticide of the present invention comprises the following components by weight percentage: 15% N-acyl amino acid from Example 1, 2.14% cocamidopropyl hydroxysulfonate betaine, 0.86% sodium cocoyl methyl taurate, and the balance being water. The termite insecticide is obtained by mixing the N-acyl amino acid, cocamidopropyl hydroxysulfonate betaine, sodium cocoyl methyl taurate, and water.

[0046] Examples 17-30 The present invention provides 14 embodiments of a termite insecticide. The termite insecticides in Examples 17-30 differ from those in Example 16 only in the N-acyl amino acid composition. Specifically... Example 17: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Example 2; Example 18: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Example 3; Example 19: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Example 4; Example 20: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Example 5; Example 21: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Example 6; Example 22: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Example 7; Example 23: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Example 8; Example 24: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Example 9; Example 25: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Example 10; Example 26: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Example 11; Example 27: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Example 12; Example 28: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Example 13; Example 29: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Example 14; Example 30: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Example 15.

[0047] Examples 31-36 The six embodiments of the termite insecticide of the present invention, the termite insecticides of embodiments 31-36 differ from those of embodiment 16 only in the content of each component of the termite insecticide. Specifically, The composition and content of the termite insecticides in Examples 16 and 31-36 are shown in Table 2. Table 2 The termite insecticide of this invention is a colorless and transparent liquid. The appearance of the termite insecticide in Example 16 is shown in the figure below. Figure 3 As shown.

[0048] Comparative Example 1 A comparative example of the method for preparing N-acyl amino acids according to the present invention includes the following steps: S1. Mix 1 mol of methyl isostearate with 1.1 mol of sodium glycinate, 0.16 mol of magnesium oxide and 0.019 mol of potassium phosphate as a mixed catalyst, and reflux at 140°C for 12 h under nitrogen protection to obtain the reactant. S2. Cool the reactants obtained in step S1 to 60°C, add dilute hydrochloric acid to acidify the reactant system to pH 1-2, separate the layers, take the supernatant, wash twice with 60°C warm water, purify the supernatant by vacuum distillation after washing to remove excess water, residual methyl ester and other impurities, and obtain a transparent liquid, which is N-acyl amino acid.

[0049] Comparative Examples 2-4 The present invention provides three comparative examples of the method for preparing N-acyl amino acids. The preparation methods of N-acyl amino acids in comparative examples 2-4 include the following steps: S1. Mix the mixture of fatty acid methyl ester A and fatty acid methyl ester B with a mixed catalyst of amino acid salt, magnesium oxide and / or potassium phosphate, and reflux at 140°C for 12 hours under nitrogen protection to obtain the reactant. S2. Cool the reactants obtained in step S1 to 60°C, add dilute hydrochloric acid to acidify the reactant system to pH 1-2, separate the layers, take the supernatant, wash twice with 60°C warm water, purify the supernatant by vacuum distillation after washing to remove excess water, residual methyl ester and other impurities, and obtain a transparent liquid, which is N-acyl amino acid.

[0050] Table 3 shows the material or content information of fatty acid methyl ester A, fatty acid methyl ester B, amino acid salt, magnesium oxide and potassium phosphate in step S1 of the preparation methods of N-acyl amino acids in Comparative Examples 1-4. Table 3 Comparative Examples 5-8 The four comparative examples of the termite insecticide of the present invention, Comparative Examples 5-8, differ from Example 16 only in the N-acyl amino acid composition. Specifically, Comparative Example 5: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid of Comparative Example 1; Comparative Example 6: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Comparative Example 2; Comparative Example 7: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Comparative Example 3; Comparative Example 8: Compared with Example 16, the N-acyl amino acid in Example 1 of Example 16 was adjusted to the N-acyl amino acid in Comparative Example 4.

[0051] Comparative Example 9 This invention provides a comparative example of a termite insecticide. The only difference between this comparative example and Example 16 is that it does not contain a co-surfactant. This comparative termite insecticide comprises the following components by mass percentage: 15% N-acyl amino acid from Example 1 and the balance being water. The preparation method of the termite insecticide is the same as in Example 16.

[0052] Comparative Example 10 This invention provides a comparative example of a termite insecticide. The only difference between this comparative example and Example 16 is the composition of the co-surfactant; the co-surfactant in this comparative example does not contain cocamidopropyl hydroxysulfonate. This comparative termite insecticide comprises the following components by weight percentage: 15% N-acyl amino acid from Example 1, 3% sodium cocoyl methyl taurate, and the balance being water. The preparation method of the termite insecticide is the same as in Example 16.

[0053] Comparative Example 11 This invention provides a comparative example of a termite insecticide. The only difference between this comparative example and Example 16 is the composition of the co-surfactant; the co-surfactant in this comparative example does not contain sodium cocoyl methyl taurate. This comparative termite insecticide comprises the following components by weight percentage: 15% N-acyl amino acid from Example 1, 3% cocamidopropyl hydroxysulfonyl betaine, and the balance being water. The preparation method of the termite insecticide is the same as in Example 16.

[0054] Comparative Example 12 This invention provides a comparative example of a termite insecticide, which is a commercially available termite insecticide: 2.5% bifenthrin emulsion.

[0055] Test Example 1 The degradation properties of the termite insecticides from Examples 16-36 and Comparative Examples 5-12 were tested.

[0056] This test was conducted according to the national standard GB / T 21856-2008 "Production Test of Rapidly Biodegradable Carbon Dioxide for Chemicals". The experimental steps are as follows: (1) The TOC content of the test substance was determined using a TOC (Total Organic Carbon) analyzer.

[0057] (2) Add a certain amount of culture medium, test substance (sample) and inoculum to a reaction vessel equipped with a NaOH absorption bottle, with a total volume of 1L, and aerate with decarbonated air (at a controlled rate of 30~100 mL / min). Among them, the inoculum is wastewater treatment soil (to provide bacterial strain), and the culture medium is the carbon-free culture medium described in the standard.

[0058] (3) Culture in darkness or diffused light for 28 days under constant temperature conditions (usually 22~25℃), and measure the amount of carbon dioxide produced by titration periodically (e.g., on days 0, 7, 14, 21, and 28).

[0059] (4) Finally, the 28-day degradation rate (D) is calculated using the following formula. When D ≥ 60%, the test substance is considered to have rapid biodegradability. The formula for calculating the degradation rate (D) is as follows: In the formula: D represents the biodegradation rate, % m1 represents the amount of carbon dioxide produced, measured in milligrams (mg). m2 represents the amount of TOC added in the experiment, expressed in milligrams (mg). 3.67 is the coefficient for the conversion of carbon to carbon dioxide (44 / 12), and the amount of carbon dioxide produced is a cumulative value.

[0060] Test results showed that the termite insecticides of Examples 16-36 had a degradation rate of 98.3%-99.6%, indicating that the termite insecticides prepared by the present invention using N-acyl amino acids, auxiliary surfactants, and water can rapidly degrade. The degradation rates of the termite insecticides of Comparative Examples 9-11 were basically consistent with those of Example 16. The degradation rate results of the termite insecticides of Examples 16-20, 25, and Comparative Examples 5-8, 12 are shown in Table 4. Table 4 Comparative Example 8, a termite insecticide prepared using stearic acid as the carbon segment, an N-acyl amino acid, an auxiliary surfactant, and water, still exhibited excellent biodegradability. Comparative Example 12, however, used a termite insecticide whose main active ingredient was bifenthrin, and it also contained organic solvents, resulting in poor biodegradability. While the low degradation rate might be beneficial for long-term control, its destructive potential to the ecological environment cannot be ignored with long-term, high-volume use.

[0061] Test Example 2 Using the termite insecticides of Examples 16-36 and Comparative Examples 5-12 as samples, the contact angles of the samples on soil and wood were tested. A contact angle meter was used to test the contact angles. Generally, a contact angle <90° indicates that the liquid can wet the solid, and a contact angle <30° indicates that the liquid can effectively wet the solid surface.

[0062] The contact angles of the termite insecticides used in Examples 16-36 and Comparative Examples 5-12 on soil and wood are shown in Table 5. Table 5 The results showed that the termite insecticides of the embodiments of the present invention had low contact angles with soil and wood blocks, and good wetting properties on the tested surfaces. While the termite insecticides of Comparative Examples 5-12 had contact angles of less than 90° with soil and wood blocks, their compatibility was weaker than that of the embodiments.

[0063] As shown in Examples 16-28, the type or molar amount of fatty acid methyl esters and amino acid salts used in the preparation of N-acyl amino acids, as well as the dosage ratio of catalysts, have a certain influence on the wetting properties of the prepared termite insecticide. Among them, a mixture of fatty acid methyl ester A and fatty acid methyl ester B is preferred, and methyl arachidonic acid ester A is preferred, while methyl isostearate ester B is preferred. A molar ratio of fatty acid methyl ester A to fatty acid methyl ester B of 9:1 is preferred. A molar ratio of fatty acid methyl ester to amino acid salt of 1:1.1~1.2 is preferred (a molar ratio of 1:1.1 is optimal). Sodium glycine is preferred as an amino acid salt. A molar ratio of fatty acid methyl ester to alkaline earth metal oxide and phosphate of 1:0.16:0.019 is preferred.

[0064] As shown in Examples 16 and 31-36, the amount of N-acyl amino acid and the amount and ratio of co-surfactant have a certain influence on the wetting performance of the prepared termite insecticide. Specifically, a mass percentage of 15-20% for the N-acyl amino acid is preferred (15% is preferred); a mass percentage of 3-5% for the co-surfactant is preferred (3% is preferred); and a mass ratio of betaine-based surfactant to diataurine-type surfactant of 1:0.35-0.45 is preferred (1:0.4 is preferred).

[0065] As shown in Example 16 and Comparative Examples 5 and 8, the preparation of fatty acid methyl esters of N-acyl amino acids affects the wetting properties of the final termite insecticide. The preparation of fatty acid methyl esters of N-acyl amino acids must contain fatty acid methyl ester A (unsaturated straight-chain fatty acid); otherwise, the wetting properties of the termite insecticide will be reduced. In the preparation of fatty acid methyl esters of N-acyl amino acids, fatty acid methyl ester A must be an unsaturated straight-chain fatty acid methyl ester, and fatty acid methyl ester B must be a saturated branched-chain fatty acid; otherwise, the wetting properties of the termite insecticide will also be reduced.

[0066] As can be seen from Example 16 and Comparative Examples 6 and 7, the catalyst for preparing N-acyl amino acids affects the wetting properties of the final termite insecticide. The catalyst for preparing N-acyl amino acids must contain both alkaline earth metal oxides and phosphates. The lack of either one will lead to a decrease in the wetting properties of the termite insecticide.

[0067] According to Example 16 and Comparative Examples 9-11, the termite insecticide contains a co-surfactant, which is superior. Furthermore, the co-surfactant contains both betaine surfactant and diataurine surfactant, which enhances the wetting properties of the termite insecticide.

[0068] As can be seen from Example 16 and Comparative Example 12, the wetting performance of commercially available termite exterminators is lower than that of the present invention, and they cannot quickly penetrate into the soil and wood blocks.

[0069] Test Example 3 The toxicity of the termite insecticides used in Examples 16-36 and Comparative Examples 5-12 was tested.

[0070] This test was conducted in accordance with the industry standard NY / T 1153.1-2013 "Efficacy Test Methods and Evaluation of Termite Control Agents for Pesticide Registration - Part 1: Toxicity of Pesticides to Termites and Laboratory Efficacy".

[0071] The experimental steps are as follows: (1) Prepare a series of sample diluents of different concentrations.

[0072] (2) Place the fine sand that has passed through a 250μm sieve into a constant temperature drying oven and keep it at 60±1℃ for 48 hours before taking it out for use.

[0073] (3) In a 90 mm diameter petri dish, evenly spread 10 g of treated fine sand, and use a pipette to evenly add 3 mL of sample diluent (the control is the same amount of distilled water) to the fine sand. Place a sheet of paper with an area of ​​about 1 cm² in each petri dish. 2 Use filter paper moistened with distilled water as food. Transplant 50 termite worker ants, cover the petri dish, and place it in an incubator under test conditions for rearing and observation.

[0074] (4) Record the number of worker ants that die at 12h, 24h and 48h after the drug is applied, and obtain the mortality rate.

[0075] (5) The median lethal concentration (LC50) of the formulation was obtained by fitting using IBM SPSS software. 50 (mg / L).

[0076] The median lethal concentration (LC50) of termite insecticides in Examples 16-36 and Comparative Examples 5-12 50 The test results (mg / L) are shown in Table 6. Table 6 The results showed that the termite insecticide of the embodiments of the present invention had a lower median lethal concentration (LD50) and higher toxicity. According to Examples 16 and 29-30, the molar range of alkaline earth metal oxides and phosphates in the catalyst for preparing N-acyl amino acids affects the toxicity of the final termite insecticide. A specific range of molar amounts of alkaline earth metal oxides and phosphates in the catalyst for preparing N-acyl amino acids is more optimal. A molar ratio of fatty acid methyl ester to alkaline earth metal oxides and phosphates of 1:0.11~0.21:0.010~0.025 results in a higher toxicity of the termite insecticide.

[0077] As shown in Example 16 and Comparative Examples 5 and 8, the preparation of fatty acid methyl esters of N-acyl amino acids affects the toxicity of the final termite insecticide. The preparation of fatty acid methyl esters of N-acyl amino acids must contain fatty acid methyl ester A (unsaturated straight-chain fatty acid); otherwise, the toxicity of the termite insecticide will be reduced. In the preparation of fatty acid methyl esters of N-acyl amino acids, fatty acid methyl ester A must be an unsaturated straight-chain fatty acid methyl ester, and fatty acid methyl ester B must be a saturated branched-chain fatty acid; otherwise, the toxicity of the termite insecticide will also be reduced.

[0078] As can be seen from Example 16 and Comparative Examples 6 and 7, the catalyst for preparing N-acyl amino acids affects the toxicity of the final termite insecticide. The catalyst for preparing N-acyl amino acids must contain both alkaline earth metal oxides and phosphates. The lack of either one will lead to a reduction in the toxicity of the termite insecticide.

[0079] According to Example 16 and Comparative Examples 9-11, the termite insecticide contains a co-surfactant, which is more desirable. Furthermore, the co-surfactant contains both betaine surfactant and diataurine surfactant, which enhances the toxicity of the termite insecticide.

[0080] As can be seen from Example 16 and Comparative Example 12, the toxicity of commercially available termite killers is lower than that of the present invention.

[0081] Test Example 4 Using the termite insecticides from Examples 16-36 and Comparative Examples 5-12 as samples, the repellency of the samples against termites was tested. The experimental steps are as follows: (1) Prepare sample dilution solutions with gradient concentrations as reagents; (2) Spread the test reagent and control reagent (distilled water) evenly on the bottom of a 9cm diameter petri dish to form two semi-circular areas.

[0082] (3) Place 20 termite worker ants at the junction and cover it.

[0083] (4) Observe once every hour and record the time the test insects stay in the treatment area within 12 hours.

[0084] (5) Calculate the avoidance rate: Avoidance rate = (time spent in the control area - time spent in the treatment area) / time spent in the control area × 100%. Test 3 times and obtain the average avoidance rate. If the average avoidance rate is ≥ 60%, it is considered effective.

[0085] The termite repellency test results of the termite insecticides used in Examples 16-36 and Comparative Examples 5-12 are shown in Table 7. Table 7 The results showed that the termite repellents of the embodiments of the present invention exhibited better termite repellency than the commercially available product of Comparative Example 12. According to Examples 16 and 29-30, the molar range of alkaline earth metal oxides and phosphates in the catalyst for preparing N-acyl amino acids affects the repellency effect of the final termite repellent. A specific range of molar amounts of alkaline earth metal oxides and phosphates in the catalyst for preparing N-acyl amino acids is more optimal. A molar ratio of fatty acid methyl ester to alkaline earth metal oxides and phosphates of 1:0.11~0.21:0.010~0.025 results in a higher repellency rate for the termite repellent.

[0086] As shown in Example 16 and Comparative Examples 5 and 8, the preparation of fatty acid methyl esters of N-acyl amino acids affects the repellency of the final termite insecticide. The preparation of fatty acid methyl esters of N-acyl amino acids must contain fatty acid methyl ester A (unsaturated straight-chain fatty acid); otherwise, the repellency of the termite insecticide will be reduced. In the preparation of fatty acid methyl esters of N-acyl amino acids, fatty acid methyl ester A must be an unsaturated straight-chain fatty acid methyl ester, and fatty acid methyl ester B must be a saturated branched-chain fatty acid; otherwise, the repellency of the termite insecticide will also be reduced.

[0087] As can be seen from Example 16 and Comparative Examples 6 and 7, the catalyst for preparing N-acyl amino acids affects the repellency performance of the final termite repellent. The catalyst for preparing N-acyl amino acids must contain both alkaline earth metal oxides and phosphates. The absence of either one will lead to a decrease in the repellency performance of the termite repellent.

[0088] According to Example 16 and Comparative Examples 9-11, the termite insecticide contains a better composition of co-surfactant, and the co-surfactant contains both betaine surfactant and diataurine surfactant, which has a synergistic effect on the repellency performance of the termite insecticide.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing an amino acid surfactant, characterized in that, Includes the following steps: S1. Mix fatty acid methyl ester with amino acid salt and catalyst, and reflux fully in a protective gas environment to obtain reactants; The fatty acid methyl ester is fatty acid methyl ester A or a mixture of fatty acid methyl ester A and fatty acid methyl ester B; fatty acid methyl ester A is an 18-26 carbon unsaturated straight-chain fatty acid methyl ester; fatty acid methyl ester B is a 10-20 carbon saturated branched fatty acid methyl ester. The catalyst is a mixture of alkaline earth metal oxides and phosphates; S2. Cool the reactants obtained in step S1 to 40~60℃, add acid to acidify, separate into layers, take the supernatant and wash it, take the washed supernatant and purify it by vacuum distillation to obtain the amino acid surfactant.

2. The preparation method according to claim 1, characterized in that, In step S1, the fatty acid methyl ester is a mixture of fatty acid methyl ester A and fatty acid methyl ester B; And / or, in step S1, the fatty acid methyl ester A includes at least one of methyl linoleate, methyl docosahexaenoic acid, methyl eicosapentaenoic acid, and methyl arachidonic acid. And / or, in step S1, the fatty acid methyl ester B includes at least one of methyl isotretinoate and methyl isostearate; And / or, in step S1, the molar ratio of fatty acid methyl ester A to fatty acid methyl ester B in the mixture of fatty acid methyl ester A and fatty acid methyl ester B is (8~9):(1~2).

3. The preparation method according to claim 1, characterized in that, In step S1, the molar ratio of the fatty acid methyl ester to the amino acid salt is 1: (1~1.2); And / or, in step S1, the amino acid salt is a neutral amino acid salt; And / or, in step S1, the molar ratio of the fatty acid methyl ester to the alkaline earth metal oxide and phosphate in the catalyst is 1:(0.08~0.21):(0.010~0.032).

4. The preparation method according to claim 3, characterized in that, In step S1, the molar ratio of the fatty acid methyl ester to the amino acid salt is 1: (1.1~1.2); And / or, in step S1, the amino acid salt is a glycine salt or an alanine salt; And / or, in step S1, the molar ratio of the fatty acid methyl ester to the alkaline earth metal oxide and phosphate in the catalyst is 1:(0.11~0.21):(0.010~0.025).

5. The preparation method according to claim 1 or 4, characterized in that, In step S1, the amino acid salt is sodium glycine or sodium alanine; And / or, in step S1, the alkaline earth metal oxide includes magnesium oxide and calcium oxide; the phosphate is potassium phosphate; And / or, in step S1, the protective gas is nitrogen; And / or, in step S1, the conditions for the full reflux reaction are a full reflux reaction at 130~170℃ for 12 hours; And / or, in step S2, the pH value of the acidification is 1~2.

6. An amino acid surfactant prepared by any one of claims 1 to 5.

7. The use of the amino acid surfactant of claim 6 in the preparation of termite control products.

8. A termite insecticide, characterized in that, It comprises the following components by weight percentage: 10-20% of the amino acid surfactant as described in claim 6, 1-5% of the co-surfactant, and the balance being water; The co-surfactant is composed of betaine-type surfactants and methyl taurine-type surfactants.

9. The termite insecticide as described in claim 8, characterized in that, The termite insecticide comprises the following components by weight percentage: 15-20% of the amino acid surfactant as described in claim 6, 3-5% of the co-surfactant, and the balance being water; And / or, the mass ratio of betaine-type surfactant to methyl taurine-type surfactant in the co-surfactant is 1:0.2~0.5; And / or, the betaine-type surfactant includes at least one of alkyl betaine, alkylamidopropyl betaine, alkyl hydroxysulfonate betaine, and alkylamidopropyl hydroxysulfonate betaine; And / or, the methyl taurine surfactant is an alkyl methyl taurate.

10. A method for preparing the termite insecticide according to claim 8 or 9, characterized in that, The amino acid surfactant, co-surfactant, and water are mixed together to obtain the product.

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