Plant source mosquito repellent liquid and preparation method thereof

Abstract

The invention discloses a botanical mosquito repellent liquid and a preparation method thereof in the technical field of pest control, and the botanical mosquito repellent liquid comprises the following components in parts by weight: 10-12 parts of composite plant essential oil, 4.2-4.6 parts of 4-n-butyl-4 '-hydroxyazobenzene, 6.2-7.9 parts of 1, 2-dibromoethane, 1.8-2.2 parts of potassium hydroxide, 3.2-3.6 parts of tris (2-aminoethyl) amine, 10-14 parts of triethylamine, 6-12 parts of 1, 2-dibromoethane, 6-12 parts of 1, 2-dibromoethane, 6-12 parts of 1, 2-dibromoethane, 6-12 parts of 1, 3-dibromoethane, 6-12 parts of 1, 3-dibromoethane, the invention relates to a hand sanitizer which is prepared from the following components in parts by weight: 20-25 parts of 1, 2-bis (triethoxysilyl) ethane, 6-8 parts of glycerinum, 6-10 parts of aloe vera gel, 2-3 parts of peppermint essential oil, 0.6-1.2 parts of vitamin E and 230-260 parts of deionized water. Mosquito repelling and avoiding of various mechanisms are achieved in the mode of preparing the composite plant essential oil, meanwhile, photosensitive microcapsules are prepared for wrapping, the sensitization risk is reduced, the stability of the plant extract is improved, and then the technical effect of long-acting mosquito repelling is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of pest control, and specifically relates to a plant-based mosquito repellent liquid and a preparation method thereof. Background Art

[0002] Botanical mosquito repellents, due to their natural, low-toxic, and environmentally friendly properties, have become a key research focus as an alternative to traditional chemical mosquito repellents. Their core active ingredients are primarily derived from essential oils and metabolites of aromatic plants, such as azadirachtin from neem seeds, citronella essential oil, extract from the long-petaled leaves of Piper nigrum, and perillaldehyde. Blending plant extracts can achieve synergistic effects, and the mechanisms of action of plant extracts involve multiple pathways: neurotoxicity, olfactory interference, and oxidative stress induction. Laboratory and field applications have demonstrated that blended formulations combined with sustained-release technology can enhance efficacy and offer significant safety advantages. Their toxicity to non-target organisms is significantly lower than that of synthetic insecticides, and some ingredients have passed skin irritation tests. However, botanical mosquito repellents still face challenges such as the poor stability of essential oil components, short efficacy due to high volatility, and the allergenic potential of some ingredients. These challenges need to be addressed through nanoencapsulation, standardized production, and toxicological evaluation. Future efforts will require the integration of multi-omics technologies to optimize formulations, gene editing to improve metabolite synthesis efficiency, and the promotion of nanomaterials and synthetic biology technologies to achieve the transition from laboratory-scale production, providing sustainable solutions for mosquito-borne disease prevention and control.

[0003] The existing technologies currently have the following main problems: 1. The effective mosquito repellent time is short, 2. The plant extracts are poorly stable, and 3. Some extracts have the risk of allergy. Summary of the Invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a plant-based mosquito repellent liquid and a preparation method thereof. In order to solve the problems of short effective mosquito repellent time, poor stability of plant extracts and the risk of sensitization of some extracts, the present invention proposes to prepare a composite plant essential oil to achieve multiple mechanisms of mosquito repellent and avoidance, and at the same time prepare photosensitive microcapsules for encapsulation to reduce the risk of sensitization and improve the stability of plant extracts, thereby achieving the technical effect of long-lasting mosquito repellent.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: The present invention proposes a plant-based mosquito repellent liquid, which includes the following components in parts by weight: 10-12 parts of composite plant essential oil, 4.2-4.6 parts of 4-n-butyl-4'-hydroxyazobenzene, 6.2-7.9 parts of 1,2-dibromoethane, 1.8-2.2 parts of potassium hydroxide, 3.2-3.6 parts of tris(2-aminoethyl)amine, 10-14 parts of triethylamine, 20-25 parts of 1,2-bis(triethoxysilyl)ethane, 6-8 parts of glycerin, 6-10 parts of aloe vera gel, 2-3 parts of peppermint essential oil, 0.6-1.2 parts of vitamin E and 230-260 parts of deionized water.

[0006] Preferably, the composite plant essential oil comprises the following components in parts by weight: 31-37 parts of lemon eucalyptus leaves, 20-28 parts of citronella, 6-10 parts of clove buds and 15-23 parts of Zanthoxylum bungeanum fruits.

[0007] Preferably, the preparation method of the composite plant essential oil specifically comprises the following steps:

[0008] (1) Fresh lemon eucalyptus leaves, citronella, clove buds and Zanthoxylum bungeanum fruits were screened to remove pests, diseases and impurities, and then washed, dried, mixed and powdered through an 80-mesh sieve to obtain composite plant powder;

[0009] (2) adding the composite plant powder obtained in step (1) to water at a material-liquid ratio of 1:10-15, adding cellulase and pectinase, soaking for 80-120 minutes, and then performing ultrasonic microwave treatment to obtain a mixture;

[0010] (3) The mixture obtained in step (2) is added to an extractor and distilled with water vapor for 90-120 minutes. The oil sample is collected and dried to obtain a composite plant essential oil.

[0011] Preferably, in step (2), the cellulase content is 0.6-0.8% of the mass of the composite plant powder; and the pectinase content is 0.3-0.4% of the mass of the composite plant powder.

[0012] Preferably, in step (2), ultrasonic microwave treatment is performed with an ultrasonic frequency of 30-40 kHz, a microwave power of 500-600 W, and a time of 50-55 min.

[0013] The present invention also provides a method for preparing a plant-based mosquito repellent liquid, which specifically comprises the following steps:

[0014] S1. Add 4-n-butyl-4'-hydroxyazobenzene to tetrahydrofuran to obtain solution 1, add 1,2-dibromoethane to tetrahydrofuran in an amount of 0.08 g / mL, and then add potassium hydroxide to obtain solution 2, add solution 2 dropwise to solution 1, heat under reflux at 75°C for 16 hours, extract with dichloromethane, dry, distill under reduced pressure, recrystallize, and purify through a silica gel column to obtain an intermediate product;

[0015] S2. Add the intermediate product obtained in S1 to tetrahydrofuran, add tris(2-aminoethyl)amine, stir and react for 30-40 minutes, then let it stand for 20-30 hours, filter, evaporate, and wash to obtain a photosensitizing surfactant;

[0016] S3. Add triethylamine to water, stir in a water bath at 80°C for 30 min to obtain a mixed solution, add the photosensitizing surfactant obtained in S2, and irradiate with a 300-320W ultraviolet light for 30-40 min to obtain a reaction solution a;

[0017] S4, uniformly mixing an acetic acid solution having a pH of 4 and ethanol in a volume ratio of 1:4, adding 1,2-bis(triethoxysilyl)ethane dropwise, stirring in a water bath, then adding the composite plant essential oil, stirring at 60-80 rpm for 10-15 min, to obtain a reaction solution b;

[0018] S5, adding the reaction solution b obtained in S4 to the reaction solution a obtained in S3, irradiating with 300-320W ultraviolet light for 15-20 minutes, stopping the irradiation and continuing the reaction for 4 hours to obtain photosensitive microcapsules;

[0019] S6. Add the photosensitive microcapsules obtained in S5 into deionized water, and then add glycerin, aloe vera gel, peppermint essential oil and vitamin E, and stir evenly to obtain a plant-based mosquito repellent liquid.

[0020] Preferably, in S1, the amount of 4-n-butyl-4'-hydroxyazobenzene added to tetrahydrofuran is 0.2-0.3 g / mL.

[0021] Preferably, in S2, the amount of the intermediate product obtained in S1 added to tetrahydrofuran is 0.02-0.03 g / mL.

[0022] Preferably, in S3, the amount of triethylamine added to water is 3-4 mg / mL.

[0023] Preferably, in S4, stirring is performed in a water bath at a temperature of 50-60°C, a speed of 80-100 rpm, and a time of 10-15 min.

[0024] The beneficial effects achieved by the present invention are as follows: the present invention selects lemon eucalyptus leaves, citronella, clove buds and bamboo-leaf pepper for combination, extracts composite plant essential oils, and realizes efficient mosquito repellent through multi-target synergistic action, wherein the citronellal in lemon eucalyptus leaves interferes with the olfactory system of mosquitoes and thereby blocks their tracking path; the citronellal and limonene in citronella can stimulate the olfactory receptors of mosquitoes and interfere with their positioning of the host, thereby avoiding mosquito bites; the eugenol in clove buds can inhibit the activity of mosquito neurotransmitters and thereby delay the judgment of mosquitoes; the alkaloids in bamboo-leaf pepper have a killing effect on mosquitoes; lemon eucalyptus leaves, citronella, clove buds and bamboo-leaf pepper are compounded to form a triple defense system of smell, touch and neurotoxicity; a photosensitive surfactant is prepared using 4-n-butyl-4'-hydroxyazobenzene, 1,2-dibromoethane and tris(2-aminoethyl)amine, Photosensitive microcapsules are prepared with triethylamine, photosensitizing surfactants and 1,2-bis(triethoxysilyl)ethane to encapsulate essential oils. The photosensitive microcapsules achieve precise controlled release in mosquito repellent liquids through their light-responsive properties, significantly improving the product's efficacy and safety. The release rate is dynamically adjusted by light intensity, accelerating the release during daytime hours with strong ultraviolet rays to cope with mosquito active periods, and slowing the release at night or in low-light environments indoors, thereby extending the effective protection time, improving product utilization and reducing excessive use caused by frequent reapplication. The physical barrier effect of the microcapsules can reduce direct contact between the mosquito repellent and the skin, and combined with the sustained-release mechanism, further reduce the risk of allergies, making it especially suitable for children and sensitive people. At the same time, it reduces the loss of active ingredients caused by factors such as high temperature. The encapsulated structure can effectively isolate the degradation of active ingredients by environmental factors, enhance chemical stability, and ensure long-lasting mosquito repellent effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Result diagram of mosquito repellent test of Examples 1-3 of the present invention and Comparative Example 1;

[0026] Figure 2 The results of skin patch tests of Examples 1-3 and Comparative Example 2 of the present invention are shown in FIG.

[0027] Figure 3 The results of the repelling time test of Examples 1-3 and Comparative Examples 1-2 of the present invention are shown in FIG.

[0028] Figure 4 The experimental results of Examples 1-3 and Comparative Example 2 are saved in the figure;

[0029] Figure 5 This is a flow chart of preparing the intermediate product according to Example 1 of the present invention;

[0030] Figure 6 This is a flow chart of preparing a photosensitive surfactant according to Example 1 of the present invention.

[0031] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods and materials similar or equivalent to those described herein can be applied to the present invention. The preferred embodiments and materials described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0034] The experimental methods in the following examples are conventional methods unless otherwise specified; the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0035] Example 1

[0036] A plant-derived mosquito repellent liquid comprises the following components in parts by weight: 10 parts of composite plant essential oil, 4.2 parts of 4-n-butyl-4'-hydroxyazobenzene, 6.2 parts of 1,2-dibromoethane, 1.8 parts of potassium hydroxide, 3.2 parts of tris(2-aminoethyl)amine, 10 parts of triethylamine, 20 parts of 1,2-bis(triethoxysilyl)ethane, 6 parts of glycerin, 6 parts of aloe vera gel, 2 parts of peppermint essential oil, 0.6 part of vitamin E and 230 parts of deionized water.

[0037] The composite plant essential oil comprises the following components in parts by weight: 31 parts of lemon eucalyptus leaves, 20 parts of citronella, 6 parts of clove buds and 15 parts of Zanthoxylum bungeanum fruits.

[0038] The preparation method of the composite plant essential oil specifically comprises the following steps:

[0039] (1) Fresh lemon eucalyptus leaves, citronella, clove buds and Zanthoxylum bungeanum fruits were screened to remove pests, diseases and impurities, and then washed, dried, mixed and powdered through an 80-mesh sieve to obtain composite plant powder;

[0040] (2) adding the composite plant powder obtained in step (1) to water at a material-liquid ratio of 1:10, adding 0.6% cellulase by weight of the composite plant powder and 0.3% pectinase by weight of the composite plant powder, soaking for 80 minutes, and then performing ultrasonic microwave treatment at an ultrasonic frequency of 30 kHz and a microwave power of 500 W for 50 minutes to obtain a mixture;

[0041] (3) The mixture obtained in step (2) is added to an extractor and distilled with water vapor for 90 minutes. The oil sample is collected and dried to obtain a composite plant essential oil.

[0042] The present invention also provides a method for preparing a plant-based mosquito repellent liquid, which specifically comprises the following steps:

[0043] S1. Add 4-n-butyl-4'-hydroxyazobenzene in an amount of 0.2 g / mL to tetrahydrofuran to obtain solution 1, add 1,2-dibromoethane in an amount of 0.08 g / mL to tetrahydrofuran, and then add potassium hydroxide to obtain solution 2, add solution 2 dropwise to solution 1, heat under reflux at 75°C for 16 h, extract with dichloromethane, dry, distill under reduced pressure, recrystallize, and purify through a silica gel column to obtain an intermediate product;

[0044] S2, adding the intermediate product obtained in S1 to tetrahydrofuran at an addition amount of 0.02 g / mL, adding tris(2-aminoethyl)amine, stirring and reacting for 30 minutes, then standing for 20 hours, filtering, evaporating, and washing to obtain a photosensitizing surfactant;

[0045] S3, adding triethylamine in an amount of 3 mg / mL to water, stirring in a water bath at 80°C for 30 min to obtain a mixed solution, adding the photosensitizing surfactant obtained in S2, and irradiating with a 300W ultraviolet light for 30 min to obtain a reaction solution a;

[0046] S4, uniformly mixing an acetic acid solution having a pH of 4 and ethanol in a volume ratio of 1:4, adding 1,2-bis(triethoxysilyl)ethane dropwise, stirring at 80 rpm in a 50° C. water bath for 10 min, then adding the composite plant essential oil, stirring at 60 rpm for 10 min, to obtain a reaction solution b;

[0047] S5, adding the reaction solution b obtained in S4 to the reaction solution a obtained in S3, irradiating with 300W ultraviolet light for 15 minutes, stopping the irradiation and continuing the reaction for 4 hours to obtain photosensitive microcapsules;

[0048] S6. Add the photosensitive microcapsules obtained in S5 into deionized water, and then add glycerin, aloe vera gel, peppermint essential oil and vitamin E, and stir evenly to obtain a plant-based mosquito repellent liquid.

[0049] Example 2

[0050] A plant-derived mosquito repellent liquid comprises the following components in parts by weight: 12 parts of composite plant essential oil, 4.6 parts of 4-n-butyl-4'-hydroxyazobenzene, 7.9 parts of 1,2-dibromoethane, 2.2 parts of potassium hydroxide, 3.6 parts of tris(2-aminoethyl)amine, 14 parts of triethylamine, 25 parts of 1,2-bis(triethoxysilyl)ethane, 8 parts of glycerin, 10 parts of aloe vera gel, 3 parts of peppermint essential oil, 1.2 parts of vitamin E and 260 parts of deionized water.

[0051] The composite plant essential oil comprises the following components in parts by weight: 37 parts of lemon eucalyptus leaves, 28 parts of citronella, 10 parts of clove buds and 23 parts of Zanthoxylum bungeanum fruits.

[0052] The preparation method of the composite plant essential oil specifically comprises the following steps:

[0053] (1) Fresh lemon eucalyptus leaves, citronella, clove buds and Zanthoxylum bungeanum fruits were screened to remove pests, diseases and impurities, and then washed, dried, mixed and powdered through an 80-mesh sieve to obtain composite plant powder;

[0054] (2) adding the composite plant powder obtained in step (1) to water at a material-liquid ratio of 1:15, adding 0.8% cellulase by weight of the composite plant powder and 0.4% pectinase by weight of the composite plant powder, soaking for 120 minutes, and then performing ultrasonic microwave treatment at an ultrasonic frequency of 40 kHz and a microwave power of 600 W for 55 minutes to obtain a mixture;

[0055] (3) The mixture obtained in step (2) is added to an extractor and distilled with water vapor for 120 minutes. The oil sample is collected and dried to obtain a composite plant essential oil.

[0056] The present invention also provides a method for preparing a plant-based mosquito repellent liquid, which specifically comprises the following steps:

[0057] S1. Add 4-n-butyl-4'-hydroxyazobenzene in an amount of 0.3 g / mL to tetrahydrofuran to obtain solution 1, add 1,2-dibromoethane in an amount of 0.08 g / mL to tetrahydrofuran, and then add potassium hydroxide to obtain solution 2, add solution 2 dropwise to solution 1, heat under reflux at 75°C for 16 h, extract with dichloromethane, dry, distill under reduced pressure, recrystallize, and purify through a silica gel column to obtain an intermediate product;

[0058] S2, adding the intermediate product obtained in S1 to tetrahydrofuran at an addition amount of 0.03 g / mL, adding tris(2-aminoethyl)amine, stirring and reacting for 40 minutes, then standing for 30 hours, filtering, evaporating, and washing to obtain a photosensitizing surfactant;

[0059] S3, adding triethylamine in an amount of 4 mg / mL to water, stirring in a water bath at 80°C for 30 min to obtain a mixed solution, adding the photosensitizing surfactant obtained in S2, and irradiating with 320W ultraviolet light for 40 min to obtain reaction solution a;

[0060] S4, uniformly mixing an acetic acid solution having a pH of 4 and ethanol in a volume ratio of 1:4, adding 1,2-bis(triethoxysilyl)ethane dropwise, stirring at 100 rpm in a 60° C. water bath for 15 min, then adding the composite plant essential oil, stirring at 80 rpm for 15 min, to obtain a reaction solution b;

[0061] S5. Add the reaction solution b obtained in S4 to the reaction solution a obtained in S3, and irradiate with 320W ultraviolet light for 20 minutes. After stopping the irradiation, continue the reaction for 4 hours to obtain photosensitive microcapsules;

[0062] S6. Add the photosensitive microcapsules obtained in S5 into deionized water, and then add glycerin, aloe vera gel, peppermint essential oil and vitamin E, and stir evenly to obtain a plant-based mosquito repellent liquid.

[0063] Example 3

[0064] A plant-derived mosquito repellent liquid comprises the following components in parts by weight: 11 parts of composite plant essential oil, 4.4 parts of 4-n-butyl-4'-hydroxyazobenzene, 7 parts of 1,2-dibromoethane, 2 parts of potassium hydroxide, 3.4 parts of tris(2-aminoethyl)amine, 12 parts of triethylamine, 22.5 parts of 1,2-bis(triethoxysilyl)ethane, 7 parts of glycerin, 8 parts of aloe vera gel, 2.5 parts of peppermint essential oil, 0.9 part of vitamin E and 240 parts of deionized water.

[0065] The composite plant essential oil comprises the following components in parts by weight: 35 parts of lemon eucalyptus leaves, 25 parts of citronella, 8 parts of clove buds and 20 parts of Zanthoxylum bungeanum fruits.

[0066] The preparation method of the composite plant essential oil specifically comprises the following steps:

[0067] (1) Fresh lemon eucalyptus leaves, citronella, clove buds and Zanthoxylum bungeanum fruits were screened to remove pests, diseases and impurities, and then washed, dried, mixed and powdered through an 80-mesh sieve to obtain composite plant powder;

[0068] (2) adding the composite plant powder obtained in step (1) to water at a material-liquid ratio of 1:12.5, adding 0.7% cellulase by weight of the composite plant powder and 0.35% pectinase by weight of the composite plant powder, soaking for 90 minutes, and then performing ultrasonic microwave treatment at an ultrasonic frequency of 35 kHz, a microwave power of 550 W, and a time of 52.5 minutes to obtain a mixture;

[0069] (3) The mixture obtained in step (2) was added to an extractor and distilled with water vapor for 105 min. The oil sample was collected and dried to obtain a composite plant essential oil.

[0070] The present invention also provides a method for preparing a plant-based mosquito repellent liquid, which specifically comprises the following steps:

[0071] S1. Add 4-n-butyl-4'-hydroxyazobenzene in an amount of 0.25 g / mL to tetrahydrofuran to obtain solution 1, add 1,2-dibromoethane in an amount of 0.08 g / mL to tetrahydrofuran, and then add potassium hydroxide to obtain solution 2, add solution 2 dropwise to solution 1, heat under reflux at 75°C for 16 h, extract with dichloromethane, dry, distill under reduced pressure, recrystallize, and purify through a silica gel column to obtain an intermediate product;

[0072] S2. The intermediate product obtained in S1 was added to tetrahydrofuran at an addition amount of 0.025 g / mL, tris(2-aminoethyl)amine was added, and the mixture was stirred for 35 minutes. The mixture was then allowed to stand for 25 hours, filtered, evaporated, and washed to obtain a photosensitizing surfactant.

[0073] S3, adding triethylamine at an addition amount of 3.5 mg / mL to water, stirring in a water bath at 80°C for 30 min to obtain a mixed solution, adding the photosensitizing surfactant obtained in S2, and irradiating with a 310W ultraviolet light for 35 min to obtain a reaction solution a;

[0074] S4, uniformly mixing an acetic acid solution having a pH of 4 and ethanol in a volume ratio of 1:4, adding 1,2-bis(triethoxysilyl)ethane dropwise, stirring at 90 rpm in a 55° C. water bath for 12.5 min, then adding the composite plant essential oil, stirring at 70 rpm for 12.5 min, to obtain a reaction solution b;

[0075] S5. Add the reaction solution b obtained in S4 to the reaction solution a obtained in S3, and irradiate with 310W ultraviolet light for 17 minutes. After stopping the irradiation, continue the reaction for 4 hours to obtain photosensitive microcapsules;

[0076] S6. Add the photosensitive microcapsules obtained in S5 into deionized water, and then add glycerin, aloe vera gel, peppermint essential oil and vitamin E, and stir evenly to obtain a plant-based mosquito repellent liquid.

[0077] Comparative Example 1

[0078] This comparative example provides a method for preparing a mosquito repellent liquid, which differs from Example 1 only in that lemongrass, clove buds, and Zanthoxylum bungeanum are replaced with equal amounts of eucalyptus citrifolia leaves, and the remaining components and component contents are the same as those in Example 1.

[0079] Comparative Example 2

[0080] This comparative example provides a method for preparing a mosquito repellent liquid, which differs from Example 1 only in that photosensitive microcapsules are not prepared, and the remaining components and component contents are the same as those in Example 1.

[0081] Experimental example

[0082] 1. Mosquito repellent test

[0083] Three transparent cylinders with a diameter of 21 cm and a length of 43 cm were connected in series. The three cylinders were separated by baffles and blocked on both sides with baffles. One side of the cylinder was sealed with a breathable gauze. 100 test mosquitoes were placed in the middle cylinder in advance. The other cylinder was filled with test essential oil and sealed with a baffle. The experimental environment temperature was set to 26°C and the relative humidity was 65%. After the essential oil samples obtained in Examples 1-3 and Comparative Examples 1-2 were placed in the cylinders for 5 minutes, the two baffles between the three cylinders were simultaneously removed. After 1 hour, the baffles were reinserted and the number of mosquitoes in the cylinders on both sides was recorded. The mosquito repellency rate was calculated using the following formula:

[0084] Mosquito repellent rate = (number of mosquitoes in blank cylinder - number of mosquitoes in drug-treated cylinder) / number of mosquitoes in blank cylinder × 100%.

[0085] Figure 1 The results of the mosquito repellent test of Examples 1-3 of the present invention and Comparative Example 1 are shown in the figure. As shown in the figure, the mosquito repellent rates of Examples 1-3 and Comparative Example 1 after being placed for 1 hour are 93%, 95%, 94% and 46%, respectively; the mosquito repellent rates of Examples 1-3 are significantly higher than those of Comparative Example 1, indicating that the use of citronella, clove buds and bamboo leaf pepper significantly improves the mosquito repellent effect of lemon eucalyptus leaves.

[0086] 2. Skin patch test

[0087] The subjects were aged 18-60 years old, with 50 males and 50 females in each group. Volunteers who met the subject support inclusion criteria were tested using a closed patch test method. 0.03 mL of the solutions of Experimental Examples 1-3 and Comparative Example 2 were added to the patch tester as the experimental group, and 0.03 mL of normal saline was added to the patch tester as the control group. The patch tester was applied to the subject's forearm and removed after 24 hours. The skin reaction was observed 2 hours after removal. A negative reaction was considered if there was no significant change before and after the patch application. The number of people with negative skin reactions was recorded, and the safety rate of the solution was calculated using the following formula:

[0088] The safety rate of the drug solution = the number of negative reactions / total number of people × 100%.

[0089] Figure 2 This is a graph showing the results of skin patch tests of Examples 1-3 of the present invention and Comparative Example 2. As shown in the figure, the safety rates of the drug solutions of Examples 1-3 and Comparative Example 2 are 100%, 100%, 100%, and 89%, respectively; the safety rate of the drug solution of Examples 1-3 is significantly higher than that of Comparative Example 2, indicating that the preparation of photosensitive microcapsules significantly improves the safety rate of the mosquito repellent solution.

[0090] 3. Repellent time test

[0091] The test was conducted according to the national standard GB / T13917.9-2009. Two male and two female subjects who passed the attack force test were selected. Both hands were put on disposable gloves with holes opened in advance. The left hand was used as the experimental hand. The test was carried out at a pressure of 1.5 μL / cm 2 The repellents of Examples 1-3 and Comparative Examples 1-2 were evenly applied to exposed skin at a dose of 100 mg / kg. The right hand served as the control and was left untreated. After 2 hours, the hand was placed in a breeding cage and observed for 2 minutes to see if any mosquitoes landed to feed on the blood. The test was repeated every 1 hour thereafter. If only one mosquito landed to feed on the blood, the repellent failed, and the effective protection time was recorded. The control hand was tested first each time. If the attack power of the test insects met the requirements, the test hand was tested. If the attack power of the test insects failed, a qualified test insect was replaced and tested again.

[0092] Figure 3 The results of the repellent time test of Examples 1-3 of the present invention and Comparative Examples 1-2 are shown in the figure. As shown in the figure, the repellent times of Examples 1-3 and Comparative Examples 1-2 are 11 hours, 12 hours, 11 hours and 9 hours, 6 hours respectively. The repellent time of Examples 1-3 is significantly higher than that of Comparative Examples 1-2, indicating that the use of citronella, clove buds and Zanthoxylum bungeanum and the preparation of photosensitive microcapsules significantly improve the mosquito repellent time.

[0093] 4. Storage performance test

[0094] In an open environment at 50°C, Examples 1-3 and Comparative Example 2 were placed in a light-proof open environment for product preservation experiments. Samples were taken after 6 days, and the content of citronellal was detected by gas chromatography using citronellal as an external standard. The citronellal content at 0 days was used as the reference value, and the preservation rate was calculated using the following formula:

[0095] Preservation rate = measured eucalyptol content / benchmark value × 100%.

[0096] Figure 4 The results of the preservation experiments of Examples 1-3 and Comparative Example 2 are shown in the figure. As shown in the figure, the preservation rates of Examples 1-3 and Comparative Example 2 at 6 days are 73.6%, 75.8%, 74.5% and 42.9%, respectively; the preservation rates of Examples 1-3 are significantly higher than those of Comparative Example 2, indicating that the preparation of photosensitive microcapsules significantly improves the preservation rate of the effective ingredients of the mosquito repellent liquid.

[0097] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

[0098] The present invention and its embodiments are described above. Such description is not restrictive. The drawings show only one embodiment of the present invention, and actual applications are not limited thereto. In short, if a person skilled in the art is inspired by the above, and does not deviate from the purpose of the present invention, any method and embodiment similar to the technical solution without creative design shall fall within the scope of protection of the present invention.

Claims

1. A plant-derived mosquito repellent liquid, characterized by: The invention comprises the following components in parts by weight: 10-12 parts of composite plant essential oil, 4.2-4.6 parts of 4-n-butyl-4'-hydroxyazobenzene, 6.2-7.9 parts of 1,2-dibromoethane, 1.8-2.2 parts of potassium hydroxide, 3.2-3.6 parts of tris(2-aminoethyl)amine, 10-14 parts of triethylamine, 20-25 parts of 1,2-bis(triethoxysilyl)ethane, 6-8 parts of glycerin, 6-10 parts of aloe vera gel, 2-3 parts of peppermint essential oil, 0.6-1.2 parts of vitamin E and 230-260 parts of deionized water; The composite plant essential oil comprises the following components in parts by weight: 31-37 parts of lemon eucalyptus leaves, 20-28 parts of citronella, 6-10 parts of clove buds and 15-23 parts of Zanthoxylum bungeanum fruits.

2. A method for preparing the plant-derived mosquito repellent liquid according to claim 1, characterized in that: The specific steps include: S1. Add 4-n-butyl-4'-hydroxyazobenzene to tetrahydrofuran to obtain solution 1, add 1,2-dibromoethane to tetrahydrofuran in an amount of 0.08 g / mL, and then add potassium hydroxide to obtain solution 2, add solution 2 dropwise to solution 1, heat under reflux at 75°C for 16 hours, extract with dichloromethane, dry, distill under reduced pressure, recrystallize, and purify through a silica gel column to obtain an intermediate product; S2. Add the intermediate product obtained in S1 to tetrahydrofuran, add tris(2-aminoethyl)amine, stir and react for 30-40 minutes, then let it stand for 20-30 hours, filter, evaporate, and wash to obtain a photosensitizing surfactant; S3. Add triethylamine to water, stir in a water bath at 80°C for 30 min to obtain a mixed solution, add the photosensitizing surfactant obtained in S2, and irradiate with a 300-320W ultraviolet light for 30-40 min to obtain a reaction solution a; S4, uniformly mixing an acetic acid solution having a pH of 4 and ethanol in a volume ratio of 1:4, adding 1,2-bis(triethoxysilyl)ethane dropwise, stirring in a water bath, then adding the composite plant essential oil, stirring at 60-80 rpm for 10-15 min, to obtain a reaction solution b; S5, adding the reaction solution b obtained in S4 to the reaction solution a obtained in S3, irradiating with 300-320W ultraviolet light for 15-20 minutes, stopping the irradiation and continuing the reaction for 4 hours to obtain photosensitive microcapsules; S6. Add the photosensitive microcapsules obtained in S5 into deionized water, and then add glycerin, aloe vera gel, peppermint essential oil and vitamin E, and stir evenly to obtain a plant-based mosquito repellent liquid.

3. The method for preparing the plant-derived mosquito repellent liquid according to claim 2, wherein: The preparation method of the composite plant essential oil specifically comprises the following steps: (1) Fresh lemon eucalyptus leaves, citronella, clove buds and Zanthoxylum bungeanum fruits were screened to remove pests, diseases and impurities, and then washed, dried, mixed and powdered through an 80-mesh sieve to obtain composite plant powder; (2) adding the composite plant powder obtained in step (1) to water at a material-liquid ratio of 1:10-15, adding cellulase and pectinase, soaking for 80-120 minutes, and then performing ultrasonic microwave treatment to obtain a mixture; (3) The mixture obtained in step (2) is added to an extractor and distilled with water vapor for 90-120 minutes. The oil sample is collected and dried to obtain a composite plant essential oil.

4. The method for preparing the plant-derived mosquito repellent liquid according to claim 2, wherein: In S1, the amount of 4-n-butyl-4'-hydroxyazobenzene added to tetrahydrofuran is 0.2-0.3 g / mL.

5. The method for preparing the plant-derived mosquito repellent liquid according to claim 4, characterized in that: In S2, the intermediate obtained in S1 is added to tetrahydrofuran in an amount of 0.02-0.03 g / mL.

6. The method for preparing the plant-derived mosquito repellent liquid according to claim 5, characterized in that: In S3, triethylamine was added in an amount of 3-4 mg / mL in deionized water.

7. The method for preparing the plant-derived mosquito repellent liquid according to claim 6, wherein: In S4, stir in a water bath at a temperature of 50-60°C, a speed of 80-100 rpm, and a time of 10-15 min.

8. The method for preparing the plant-derived mosquito repellent liquid according to claim 3, wherein: In step (2), the cellulase content is 0.6-0.8% of the mass of the composite plant powder; the pectinase content is 0.3-0.4% of the mass of the composite plant powder.

9. The method for preparing the plant-derived mosquito repellent liquid according to claim 8, characterized in that: In step (2), ultrasonic microwave treatment is performed with an ultrasonic frequency of 30-40 kHz, a microwave power of 500-600 W, and a time of 50-55 min.

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