CN110999907A - Microcapsule slow-release mosquito repellent containing menthanediol and 2-undecanone - Google Patents

Abstract

The invention discloses a microcapsule slow-release mosquito repellent containing menthanediol and 2-undecanone, and relates to the technical field of agricultural chemical industry. 5-15% of menthanol and 5-15% of menthanol are used as core materials, 70-90% of chitosan and a very small amount of PLGA are used as wall materials, and the microcapsule is prepared by a spray drying process. The release amount is detected by using a gas chromatography to prove that the slow release period of the microcapsule is not less than 90 days.

Description

Microcapsule slow-release mosquito repellent containing menthanediol and 2-undecanone

Technical Field

The invention relates to the technical field of agricultural chemicals, in particular to a microcapsule slow-release mosquito repellent containing menthanediol and 2-undecanone.

Background

Mosquitoes are common insects with piercing and sucking mouthparts, and the females often take human blood as food. The discomfort of red swelling and pruritus of the skin can be brought to people by mosquito bites. Mosquitoes are also intermediate hosts for severe infectious diseases such as dengue fever, malaria, yellow fever, and the like. The periphery of mill generally is provided with greenbelt and escape canal and leads to the mosquito to breed in a large number, and current kill mosquito means commonly used is for spraying medicines such as cypermethrin and setting up the mosquito killer lamp. The cypermethrin and other medicines can keep the mosquito killing effect for about 7 days, the effect of controlling the population scale can be achieved only through frequent use, and the mosquito killing lamp can attract male mosquitoes and is difficult to kill blood-sucking female mosquitoes.

Safe, effective, large-range and durable mosquito repellent products are important for keeping clean environment of factories.

The menthanol is an effective component in the eucalyptus citriodora essential oil, can also be synthesized by taking citronellal as a raw material, and belongs to a relatively natural and safe effective component. It is recognized by the U.S. EPA/CDC and is recommended as one of the five most effective mosquito repellents, and the only one among them is that derived from natural plant extracts. The menthandiol is insoluble in water, is difficult to directly prepare a high-concentration product in a water system, and is difficult to persist because the menthandiol directly uses solid powder because of easy sublimation/volatilization.

2-undecanone is a common fragrance and mosquito repellent. It is harmless to human body, and can be widely used in preparation of medicines, spices and partial foods. 2-undecanone also has excellent mosquito repellent effect, it is approved by the U.S. EPA and is evaluated as one of the five most effective mosquito repellents. 2-undecanone itself has a strong odor which is unpleasant to smell, while microcapsules can be well delayed and masked.

Disclosure of Invention

The invention provides a method for preparing a microcapsule slow-release mosquito repellent containing menthanediol and 2-undecanone.

The process comprises the following steps:

dispersing chitosan in water, and regulating pH to 5.0 with glacial acetic acid to completely dissolve chitosan to obtain 2% chitosan water solution;

dispersing menthanol and 2-undecanone in a chitosan aqueous solution, adding 0.5% Tween-80 in volume of the chitosan aqueous solution, and homogenizing at high speed for more than 2 hours to obtain a primary emulsion;

spray drying the primary emulsion at the air inlet temperature of 160 ℃ and the air outlet temperature of 90 ℃ to obtain white powder;

washing the white powder with 0.2% sodium hydroxide solution at a material-to-liquid ratio of 1:20, drying, then fully soaking with 0.5% PLGA dichloromethane solution, filtering out the excessive PLGA dichloromethane solution, and drying to obtain the finished product.

Detailed Description

The present invention is described in detail below with reference to examples, but the present invention is not limited thereto, and in the following examples, the percentages referred to are calculated by weight unless otherwise specified.

Firstly, the invention relates to a preparation process of a sustained-release microcapsule.

Dispersing chitosan in water, and regulating pH to 5.0 with glacial acetic acid to completely dissolve chitosan to obtain 2% chitosan water solution;

dispersing menthanol and 2-undecanone in a chitosan aqueous solution, adding 0.5% Tween-80 in volume of the chitosan aqueous solution, and homogenizing at high speed for more than 2 hours to obtain a primary emulsion;

spray drying the primary emulsion at the air inlet temperature of 160 ℃ and the air outlet temperature of 90 ℃ to obtain white powder;

washing the white powder with 0.2% sodium hydroxide solution at a material-to-liquid ratio of 1:20, drying, then fully soaking with 0.5% PLGA dichloromethane solution, filtering out excessive PLGA dichloromethane solution, drying to obtain the finished product, and calculating the yield.

The formulations and results for examples 1-6 are as follows.

And secondly, slow release experiment.

1g of the mosquito repellent powder obtained in the examples 1 to 6 is uniformly placed in an open surface dish; placing the watch glass in a biochemical incubator for 90 days at 35 ℃; taking 0.01g every 10 days, carrying out ultrasonic dissolution by using dichloromethane, then fixing the volume to 10 mL, measuring the contents of menthanol and 2-undecanone in the solution by using a gas chromatograph, and calculating the release amount; five experiments were performed in parallel and averaged.

Experimental results show that the microcapsule slow-release mosquito repellent has a good slow-release effect, and different material ratios can be selected according to different use conditions to achieve a proper environment release concentration.

Claims (3)

1. A microcapsule slow-release mosquito repellent containing menthanediol and 2-undecanone is characterized in that the menthanediol and 2-undecanone are used as core materials, chitosan and PLGA are used as wall materials, and the microcapsule is prepared by a spray drying process.

2. The microcapsule slow-release mosquito repellent according to claim 1, wherein the added amount of the menthandiol is 5% -15%, the added amount of the 2-undecanone is 5% -15%, the added amount of the chitosan is 70% -90%, and the added amount of the PLGA is very small.

3. The microcapsule slow-release mosquito repellent according to claim 1, and the preparation process comprises the following steps:

dispersing chitosan in water, and regulating pH to 5.0 with glacial acetic acid to completely dissolve chitosan to obtain 2% chitosan water solution;

dispersing menthanol and 2-undecanone in a chitosan aqueous solution, adding 0.5% Tween-80 in volume of the chitosan aqueous solution, and homogenizing at high speed for more than 2 hours to obtain a primary emulsion;

spray drying the primary emulsion at the air inlet temperature of 160 ℃ and the air outlet temperature of 90 ℃ to obtain white powder;

washing the white powder with 0.2% sodium hydroxide solution at a material-to-liquid ratio of 1:20, drying, then fully soaking with 0.5% PLGA dichloromethane solution, filtering out the excessive PLGA dichloromethane solution, and drying to obtain the finished product.