A room temperature volatile mosquito repellent liquid and preparation method thereof

Abstract

The invention discloses a room temperature volatile mosquito repellent liquid and a preparation method thereof. The mosquito repellent liquid comprises the following components by weight: 0.1 to 20 parts of malic acid ester; 0.1 to 40 parts of plant essential oil; and 40 to 99.8 parts of diluent. The mosquito repellent liquid has a self-volatile characteristic, has a good long-term mosquito repellent effect without heating, has high stability and safety, does not contain chemical pesticide mosquito repellent components, is harmless to the human body, and has a special aroma. The preparation method is simple, low-cost, and suitable for industrial applications.

Description

Technical Field

[0001] The invention relates to a mosquito repellent liquid, in particular to a room temperature volatile mosquito repellent liquid and a preparation method thereof, belonging to the technical field of mosquito repellent preparation. Background Art

[0002] Mosquito bites can cause the spread of many human diseases. Effectively preventing mosquito bites and preventing diseases is also a global public health problem. In recent years, with the change of people's daily consumption habits in preventing mosquito bites and the improvement of quality of life, the market demand for mosquito repellent products has increased, and there are more and more types of mosquito repellent products on the market. Among the existing mosquito repellent liquid products on the market, spray or smear type mosquito repellent liquid generally adds DEET, chlorpyrifos, and hydroxybenzoate as active ingredients. It needs to act on the surface of human skin or clothing to form an aerosol barrier to interfere with the mosquito's nervous system to achieve a mosquito repellent effect. Therefore, it is more suitable for outdoor and sports use. Electric mosquito coil liquid products use pyrethroid hygienic pesticides. The pyrethroid pesticide components are volatilized into the air through an electric heating device to repel mosquitoes. It is suitable for repelling mosquitoes within a certain space.

[0003] For some flavor compounds or plant extracts used in indoor spaces, after volatilization into the indoor space, although they cannot knock down mosquitoes, the special smell they produce is not liked by mosquitoes, and can also achieve the purpose of driving mosquitoes out of a certain space. Such ingredients generally have special fruity or plant fragrances, and they also have the effect of refreshing the air and refreshing the mind during use. my country is rich in plant resources, and plant essential oils have the advantages of wide sources, good volatility, low environmental pollution, and low toxicity. Some plant extracts have both fumigation knockdown activity and repellent activity, and are more suitable for indoor pest control.

[0004] Among the technologies reported so far, the document "Synthesis of diamyl malate repellent" (Sichuan Chemical Industry, Issue 1, 1989) provides a synthetic research experiment of diamyl malate compounds that can be used as repellents. This technology uses concentrated sulfuric acid as a catalyst to synthesize diamyl malate through esterification reaction, with a yield of 90% and a purity of 98.6%. The document "Solid Superacid SO4 2- / Study on the Synthesis of Diisoamyl Malate Catalyzed by TiO2" (Journal of Yulin Normal University, Vol. 27, No. 3, 2006), "Solid Superacid SO4 2- / Research on the Synthesis of Dibutyl Malate Catalyzed by TiO2" (Chemical Technology and Development, Vol. 37, No. 1, 2008) reported the use of solid superacid SO4 2- / TiO2 catalyst is used to synthesize diisoamyl malate and dibutyl malate. The esterification rate of diisoamyl malate synthesized with benzene as the water carrier can reach 93.4%, and the esterification rate of dibutyl malate can reach more than 90%. The document "Synthesis of Diisoamyl Malate by Single Focused Microwave Catalysis" (Jiangxi Chemical Industry, Issue 4, 2017) uses a microwave chemical conversion synthesis reactor and concentrated sulfuric acid to catalyze the synthesis reaction to prepare diisoamyl malate, and the esterification rate can reach 93.6%. Among the currently reported methods for synthesizing malic acid esters, H2SO4 or H2SO4-impregnated SO4 is mainly used. 2- / TiO2 powder type solid acid catalyst preparation, and such reports do not involve product dosage forms and usage methods using malic acid ester as mosquito repellent ingredient.

[0005] Patent CN108991040A discloses a mosquito repellent aromatherapy liquid and a preparation method thereof, which is prepared using plant ingredients such as rose oil, rose oil, sunflower seed oil, and basil essential oil, and the mosquito repellent time meets the overnight requirement.

[0006] Patent CN104824045A discloses a mosquito repellent method using a natural mosquito repellent aromatherapy vine oil composition, which uses plant components such as peppermint oil, eucalyptus oil, camphor oil, clove oil, etc. as effective ingredients, and the mosquito repellent KT50 value reaches the A-level standard.

[0007] Patent CN103462834A discloses a room temperature volatile natural plant essential oil mosquito repellent gel, which uses lavender oil, eucalyptus oil, citronella oil, and wormwood oil as effective mosquito repellent ingredients. The product is made in the form of a gel to prolong the release time of the product's effective ingredients.

[0008] Patent CN101669529 discloses an aromatherapy mosquito repellent composition, which is compounded with plant essential oils such as eucalyptus oil, tea tree oil, lemon eucalyptus oil, etc., and added with diluent alkane C14. When used, the active ingredients are brought into the space where mosquitoes need to be repelled by spraying or electrothermal volatilization to achieve mosquito repellence.

[0009] Patent CN108684701A discloses a composition and product for repelling and killing mosquitoes, wherein the volatile active ingredients are selected from one or more of pesticides such as cypermethrin, tetrafluthrin, transfluthrin, metofluthrin, and pralothrin, and the product is suitable for electrically heated volatilization and self-volatilization type products.

[0010] At present, there are several main problems with volatile space mosquito repellent products: first, most of them use electric heating to release the active ingredients. Under long-term heating, the pesticide components will inevitably undergo some chemical reactions to produce impurities; second, most plant essential oils used to repel mosquitoes have little effect on repelling mosquitoes; third, the release of the active ingredients in the product is unstable, and the volatilization speed is too fast or too slow, making it difficult to ensure long-term and effective mosquito repellent effect. Summary of the invention

[0011] In view of the shortcomings of the prior art such as poor safety performance, stability and poor mosquito repellent effect, the present invention aims to provide a room temperature volatile mosquito repellent liquid. The mosquito repellent liquid has the characteristics of self-volatilization at room temperature, safe ingredients and good mosquito repellent effect.

[0012] Another object of the present invention is to provide a method for preparing a room temperature volatile mosquito repellent liquid. The method is simple, low cost, green and environmentally friendly, and suitable for industrial application.

[0013] In order to achieve the above technical objectives, the present invention discloses a room temperature volatile mosquito repellent liquid, which comprises the following components by weight:

[0014] 0.1-20 parts of malic acid ester;

[0015] 0.1-40 parts of plant essential oil;

[0016] 40 to 99.8 parts of diluent.

[0017] The mosquito repellent liquid of the present invention adopts the above-mentioned component ratio and can self-volatize at room temperature to achieve an effective mosquito repellent effect, wherein the malic acid ester has the characteristics of spatial repellency and long volatilization time, and the plant essential oil and the diluent can synergistically promote the volatilization of the mosquito repellent effective ingredients, adjust the aroma effect of the mosquito repellent liquid, and prolong the mosquito repellent effect.

[0018] As a preferred solution, the mass fraction of the malic acid ester is 5 to 15 parts.

[0019] As a preferred solution, the plant essential oil includes bergamot essential oil. Among them, bergamot essential oil can produce a refreshing effect after being diffused indoors, which can not only make people feel relaxed and happy, resist depression, eliminate tension, but also have the effect of repelling insects, and even purifying the air and preventing the spread of viruses.

[0020] As a preferred solution, the plant essential oil also includes hyssop essential oil and / or cedar essential oil. Hyssop essential oil can inhibit the reproduction of bacteria in the air and help relieve anxiety and fatigue; cedar essential oil is extracted from cedar plants and has a light and elegant woody fragrance. It is a good insect repellent and can relieve stress, relax nerves, and improve nervous tension and anxiety after volatilizing into the air. The plant essential oil formula used in the present invention can better synergize with malic acid esters, improve mosquito repellent effects, and at the same time give the product a unique plant fragrance effect.

[0021] As a preferred solution, the mass proportion of the bergamot essential oil is 0.1 to 20 parts, the mass proportion of the hyssop essential oil is 0 to 10 parts, and the mass proportion of the cedar essential oil is 0 to 10 parts. The use of this combination of plant essential oils is conducive to the mosquito repellent to fully exert its effect.

[0022] As a preferred solution, the diluent includes at least one of isododecane, 3-methoxy-3-methylbutanol, and ethanol. The use of this type of diluent can ensure that the mosquito repellent liquid is uniform and stable, and at the same time, the mosquito repellent liquid has a suitable self-volatilization effect, thereby improving product stability.

[0023] The present invention also provides a method for preparing a room temperature volatile mosquito repellent liquid, which comprises mixing raw materials including malic acid, alkanol, cyclohexane and a catalyst for esterification reaction to obtain malic acid ester; and mixing the malic acid ester with plant essential oil and a diluent to obtain the product.

[0024] In the present invention, malic acid and alkanol are reacted by esterification to obtain malic acid ester, the esterification rate of which is greater than 95%, the product purity of which is greater than 98.5%, and the high-quality malic acid ester can be better compounded with plant essential oils and diluents to improve the performance of mosquito repellent. Among them, cyclohexane is used as a solvent and dehydrating agent in the reaction process. On the one hand, the use of benzene solvent with high toxicity can be avoided. On the other hand, the removal of water is conducive to the forward progress of the esterification reaction and improves the efficiency of the esterification reaction. The basic principle of the esterification reaction is as follows:

[0025]

[0026] As a preferred embodiment, the alkanol includes C3-C8 alcohols, more preferably C3-C8 monohydric alcohols, and most preferably C5 primary alcohols.

[0027] As a preferred embodiment, the molar ratio of malic acid to alkanol is 1:2-4, and more preferably 1:2.1-2.5.

[0028] As a preferred solution, the catalyst is a polymer solid acid particle catalyst loaded with sulfonic acid groups. The particle size of the catalyst is 0.5 to 3 mm. The catalyst has good reaction activity, strong selectivity, and few side reactions, effectively avoiding the use of sulfuric acid catalysts with strong oxidizing and corrosive properties. In addition, the large-size particle catalyst is easy to separate and remove, avoiding the reaction solution neutralization and water washing process.

[0029] As a preferred solution, the amount of the catalyst is 0.05-5% of the total mass of the mixed raw materials, and more preferably 0.2-1%.

[0030] As a preferred solution, the amount of cyclohexane used is 20-50% of the total mass of the mixed raw materials.

[0031] As a preferred solution, the conditions of the esterification reaction are: temperature of 90-160°C and time of 3-6 hours. More preferably, the esterification reaction temperature is 120-150°C.

[0032] As a preferred solution, after the esterification reaction is completed, the obtained reaction solution is subjected to solid-liquid separation, and the obtained solution is sequentially washed and distilled to obtain malic acid ester. Saturated salt water is used as a detergent in the washing process.

[0033] Compared with the prior art, the advantages of the present invention are:

[0034] (1) The mosquito repellent liquid can volatilize at room temperature through auxiliary tools such as fiber sticks or volatilization sticks, and can achieve long-term mosquito repellency without a heating device. It has high safety, strong stability, and good mosquito repellent effect;

[0035] (2) The mosquito repellent does not contain any harmful chemical ingredients and has a pleasant special aroma. It is harmless to the human body, green and environmentally friendly, and also has certain health benefits;

[0036] (3) The preparation method is simple and low in cost. The yield of the self-made malic acid ester of the present invention is high, the product purity is high, and the quality is good, which is conducive to compounding with plant essential oils and diluents to improve the performance of mosquito repellent liquid. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below in conjunction with specific implementation modes.

[0038] The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0039] Example 1

[0040] In 1L reactor, add L-malic acid 150g, n-amyl alcohol 300 grams, cyclohexane 240g, solid acid catalyst 3g, stirring heating reflux, react at 120 ℃ for 4h, esterification rate 95.1% (in terms of L-malic acid) after reaction, reduce material temperature below 80 ℃ to filter catalyst, add saturated salt water to wash twice. After liquid separation, remove solvent, vacuum distillation to collect n-amyl malate, purity 99.1%, yield 91.6% (in terms of L-malic acid). Take prepared n-amyl malate 50g, then add bergamot essential oil 50g, cypress essential oil 10g, cedar essential oil 10g, then add 3-methoxy-3-methylbutanol 200g, ethanol 80g, stir evenly, sample and test qualified after filling, obtain room temperature self-volatile mosquito repellent 400g.

[0041] Example 2

[0042] In a 1L reactor, add L-malic acid 150g, isoamyl alcohol 300g, cyclohexane 240g, solid acid catalyst 3g, stir and heat reflux, react at 120 ℃ for 4h, esterification rate 94.3% (in terms of L-malic acid), after the reaction is completed, reduce the material temperature below 80 ℃ to filter the catalyst, add saturated salt water and wash twice. After liquid separation, remove the solvent, and collect n-amyl malate by vacuum distillation, with a purity of 99.3%. Take 50g of prepared isoamyl malate, then add 50g of bergamot essential oil, 10g of hyssop essential oil, 10g of cedar essential oil, then add 200g of 3-methoxy-3-methylbutanol, 80g of ethanol, stir evenly, fill after sampling and testing, and obtain 400g of self-volatile mosquito repellent at room temperature.

[0043] Example 3

[0044] In a 1L reactor, add 150g of DL-malic acid, 320 grams of n-amyl alcohol, 240g of cyclohexane, and 3g of solid acid catalyst, stir and heat under reflux, react at 120°C for 4h, esterification rate 95.0% (in terms of DL-malic acid). After the reaction is completed, reduce the material temperature below 80°C to filter the catalyst, add saturated salt water and wash twice. After liquid separation, remove the solvent, and collect n-amyl malate by vacuum distillation, with a purity of 99.1%. Take 50g of prepared n-amyl malate, then add 50g of bergamot essential oil, 10g of hyssop essential oil, and 10g of cedar essential oil, then add 200g of 3-methoxy-3-methylbutanol and 80g of ethanol, stir evenly, fill after sampling and testing, and obtain 400g of self-volatile mosquito repellent at room temperature.

[0045] Example 4

[0046] In a 1L reactor, add L-malic acid 150g, n-amyl alcohol 300g, cyclohexane 240g, solid acid catalyst 2.5g, stir and heat reflux, react at 120 ℃ for 3h, esterification rate 93.8% (in terms of L-malic acid) after the reaction is completed, reduce the material temperature below 80 ℃ to filter the catalyst, add saturated salt water and wash twice. After liquid separation, remove the solvent, and collect n-amyl malate by vacuum distillation, with a purity of 99.2%. Take 40g of prepared n-amyl malate, then add 40g of bergamot essential oil, 20g of hyssop essential oil, 20g of cedar essential oil, 200g of 3-methoxy-3-methylbutanol, 80g of isomeric dodecane, stir evenly, fill after sampling and testing, and obtain 400g of self-volatile mosquito repellent at room temperature.

[0047] Example 5

[0048] In a 1L reactor, add L-malic acid 150g, isoamyl alcohol 300g, cyclohexane 200g, solid acid catalyst 3g, stir and heat reflux, react at 125 ℃ for 3.5h, esterification rate 94.3% (in terms of L-malic acid). After the reaction is completed, reduce the material temperature below 80 ℃ to filter the catalyst, add saturated salt water and wash twice. After liquid separation, remove the solvent, and collect n-amyl malate by vacuum distillation, with a purity of 99.0%. Take 10g of prepared isoamyl malate, then add 40g of bergamot essential oil, 10g of hyssop essential oil, 10g of cedar essential oil, then add 200g of 3-methoxy-3-methylbutanol, 130g of ethanol, stir evenly, fill after sampling and testing, and obtain 400g of self-volatile mosquito repellent at room temperature.

[0049] Example 6

[0050] In a 1L reactor, add L-malic acid 180g, n-amyl alcohol 300g, cyclohexane 200g, solid acid catalyst 2.5g, stir and heat reflux, react at 120 ℃ for 3h, esterification rate 92.8% (in terms of L-malic acid) after the reaction is completed, reduce the material temperature below 80 ℃ to filter the catalyst, add saturated salt water and wash twice. After liquid separation, remove the solvent, and collect n-amyl malate by vacuum distillation, with a purity of 99.0%. Take 50g of prepared n-amyl malate, then add 15g of bergamot essential oil, 15g of hyssop essential oil, 15g of cedar essential oil, then add 100g of 3-methoxy-3-methylbutanol, 100g of ethanol, 100g of isomeric dodecane, stir evenly, fill after sampling and testing, and obtain 385g of self-volatile mosquito repellent at room temperature.

[0051] Example 7

[0052] In a 1L reactor, add L-malic acid 180g, n-butanol 280g, cyclohexane 200g, solid acid catalyst 3g, stir and heat reflux, react at 120℃ for 4h, esterification rate 94.2% (in terms of L-malic acid) after the reaction is completed, reduce the material temperature below 80℃ to filter the catalyst, add saturated salt water and wash twice. Remove the solvent after liquid separation, and collect n-pentyl malate by vacuum distillation, with a purity of 99.2%. Take 50g of prepared n-butyl malate, then add 15g of bergamot essential oil, 15g of hyssop essential oil, 15g of cedar essential oil, then add 100g of 3-methoxy-3-methylbutanol, 100g of ethanol, 100g of isomeric dodecane, stir evenly, fill after sampling and testing, and obtain 385g of self-volatile mosquito repellent at room temperature.

[0053] Example 8

[0054] In a 1L reactor, add L-malic acid 180g, n-hexanol 320g, cyclohexane 200g, solid acid catalyst 4g, stir and heat reflux, react at 120 ℃ for 4h, esterification rate 95.7% (in terms of L-malic acid) after the reaction is completed, reduce the material temperature below 80 ℃ to filter the catalyst, add saturated salt water and wash twice. After liquid separation, remove the solvent, and collect n-pentyl malate by vacuum distillation, with a purity of 98.9%. Take 50g of prepared n-hexyl malate, then add 15g of bergamot essential oil, 15g of hyssop essential oil, 15g of cedar essential oil, then add 100g of 3-methoxy-3-methylbutanol, 100g of ethanol, 100g of isomeric dodecane, stir evenly, fill after sampling and testing, and obtain 385g of self-volatile mosquito repellent at room temperature.

[0055] The mosquito repellent effect of the product was tested in a space mosquito repellent test box (150cm×30cm×30cm) at a room temperature of 25-28℃ and a relative humidity of (60±10)%. The mosquito activity room is divided into three sections: A, B, and C. The test mosquito is Aedes albopictus, and female mosquitoes that have not sucked blood for 3-5 days after emergence are selected for testing. First, mosquitoes are put into the mosquito activity room through the mosquito release port, and the mosquitoes can fly freely in the experimental box. During the test, 0.2g of the freshly prepared sample is dropped on the filter paper in the culture dish, and the mosquito repellent liquid sample is placed in the mosquito activity room at the left end of box A for mosquito repellent experiment. Mosquitoes are affected by the mosquito repellent liquid and choose to stay in the space. The number of mosquitoes in each section of each mosquito activity room is counted at 5min and 20min respectively, and the spatial repellency rate is calculated.

[0056]

[0057] The test results of the spatial mosquito repellent effect of each embodiment and control product are shown in Table 1 and Table 2.

[0058] Table 1 Example sample test results

[0059] Test samples 5min space repellency rate, % 20min space repellency rate, % Example 1 92.6 97.5 Example 2 90.8 95.3 Example 3 89.4 93.2 Example 4 91.5 93.8 Example 5 89.2 94.3 Example 6 90.2 96.2 Example 7 89.3 91.2 Example 8 87.4 90.4

[0060] Table 2 Malic acid ester and plant essential oil comparative test results

[0061]

[0062]

[0063] (Note: The electric mosquito coil liquid contains 0.6% hexafluthrin)

[0064] In order to test the mosquito repellent effect of the sample after long-term self-volatilization, the diluent component and dosage were fixed, and the comparative mosquito repellent liquid with different effective ingredients was prepared, wherein the diluent dosage was 75% by mass, and the diluent ratio was 3-methoxy-3-methylbutanol and ethanol in a mass ratio of 3:1. Take 50ml of the prepared Example 1 and the comparative example sample (wherein, the mass ratio of bergamot oil to hyssop oil and cedar oil in comparative example 21 was 5:1:1) and put it into a 60ml small-mouthed glass bottle, insert 3 self-volatilizing fiber rods with a diameter of 3mm and a length of 12cm, and place it at 25-30℃ indoors for natural volatilization. On the 7th and 21st days of self-volatilization, the 5min and 20min space repellency of the self-volatilizing sample were tested respectively, and the test results are shown in Table 3.

[0065] Table 3 Comparative test results of malic acid ester and plant essential oil with diluent

[0066]

[0067]

[0068] The essential oils selected in the comparative test were all verified to have a certain spatial mosquito repellent effect. After 21 days of self-evaporation, the room temperature self-evaporating mosquito repellent liquid prepared in the embodiment of the present invention had a more significant spatial mosquito repellent effect than using malic acid ester and plant essential oil alone.

[0069] In order to test the mosquito repellent effect of the embodiment after long-term self-volatilization, different ratios of diluents were designed and their repellency was tested after a certain period of volatilization. 100g of n-pentyl malate prepared in Example 1 was selected, and then 100g of bergamot essential oil, 20g of hyssop essential oil, and 20g of cedar essential oil were added, and the self-volatile mosquito repellent matrix component was prepared after mixing. A certain amount of matrix sample was taken and put into a small-mouthed glass bottle, and 30g of diluent in different proportions was added. After stirring, 3 self-volatile fiber rods with a diameter of 3mm and a length of 12cm were inserted, and placed in a room at 25-30℃ for natural volatilization. After a certain period of time, the 20min space repellency of the self-volatile sample was tested, and the test results are shown in Table 4.

[0070] Table 4 Effect of diluent composition on repellent effect

[0071]

[0072]

Claims

1. A room temperature volatile mosquito repellent liquid, characterized in that: It is composed of the following components by mass: 0.1-20 parts of malic acid ester; 0.1~40 parts of plant essential oil; 40~99.8 parts of diluent; The malic acid ester is composed of at least one of n-amyl malate, isoamyl malate, n-butyl malate and n-hexyl malate; The plant essential oil consists of bergamot essential oil, hyssop essential oil and cedar essential oil; The mass proportion of the bergamot essential oil is 0.1 to 20 parts; The mass portion of the hyssop essential oil does not exceed 10 parts; The mass proportion of the cedar essential oil does not exceed 10 parts; The diluent is composed of at least one of isododecane and ethanol, and 3-methoxy-3-methylbutanol.

2. The method for preparing a room temperature volatile mosquito repellent liquid according to claim 1, characterized in that: The raw materials including malic acid, alkanol, cyclohexane and a catalyst are mixed for esterification reaction to obtain malic acid ester; the malic acid ester is mixed with plant essential oil and a diluent to obtain the product.

3. The method for preparing a room temperature volatile mosquito repellent liquid according to claim 2, characterized in that: The alkanol includes C3~C8 alcohol; The molar ratio of malic acid to alkanol is 1:2-4.

4. The method for preparing a room temperature volatile mosquito repellent liquid according to claim 2, characterized in that: The catalyst is a polymer solid acid particle catalyst loaded with sulfonic acid groups; The particle size of the catalyst is 0.5-3 mm; The amount of the catalyst is 0.05-5% of the total mass of the mixed raw materials.

5. The method for preparing a room temperature volatile mosquito repellent liquid according to claim 2 or 4, characterized in that: The amount of cyclohexane used is 20-50% of the total mass of the mixed raw materials.

6. The method for preparing a room temperature volatile mosquito repellent liquid according to claim 2, characterized in that: The conditions of the esterification reaction are: temperature of 90-160° C. and time of 3-6 hours.

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