Preparation method of citral solution, citral miniemulsion and preparation method of citral miniemulsion

Abstract

The invention belongs to the field of citral extraction, and discloses a preparation method of a citral solution, a citral miniemulsion and a preparation method of the citral miniemulsion. The preparation method of the citral solution comprises the following steps: preparing trifluoroacetaldehyde hemiethanol, 2-(trifluoromethoxy) ethanol, 2, 2-difluoroethanol and ethanol into a fluorine-alcohol mixed solution; taking the fluorine alcohol mixed solution, and adding alkanol to prepare a fluorine alcohol-alkanol solution; adding deionized water into the fluoroalcohol-alkanol solution, carrying out uniform vortex mixing, and carrying out centrifugal separation to obtain an MFHO-alkanol supramolecular solvent; uniformly mixing the MFHO-alkanol supramolecular solvent, deionized water and the citrus peel concentrate dilute solution in a vortex manner, and performing centrifugal separation to obtain a citral solution. The extraction method is simple, reliable and high in extraction efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of citral extraction, and particularly relates to a preparation method of citral solution, a citral fine emulsion and a preparation method thereof. BACKGROUND

[0002] Citrus peel is a natural food by-product, which contains various bioactive substances and has physiological functions such as antioxidant, hypoglycemic and hypolipidemic effects. However, the effective component content of the citrus peel is low, and the development and utilization value is low. Citral in the citrus peel has excellent anti-free radical performance and good insect and mosquito repellent performance. In the extraction process, the extraction efficiency is always low due to the influence of the dense structure formed by the interweaving of cellulose, hemicellulose and pectin in the cell wall of the peel. SUMMARY

[0003] The main purpose of the present application is to provide a preparation method of citral solution, a citral fine emulsion and a preparation method thereof, and to solve the problem of low extraction efficiency of citral.

[0004] To achieve the above-mentioned purpose, the present application provides a preparation method of citral solution, comprising:

[0005] Trifluoroacetaldehyde hemiethanol, 2-(trifluoromethoxy)ethanol, 2,2-difluoroethanol and ethanol are configured into a fluorine alcohol mixed solution;

[0006] The fluorine alcohol mixed solution is taken, and an alkyl alcohol is added to form a fluorine alcohol-alkyl alcohol solution;

[0007] Deionized water is added to the fluorine alcohol-alkyl alcohol solution, and stirred and mixed uniformly, and then centrifuged to obtain an MFHO-alkyl alcohol supramolecular solvent;

[0008] The MFHO-alkyl alcohol supramolecular solvent, deionized water and a citrus peel concentrate dilute solution are stirred and mixed uniformly, and then centrifuged to obtain a citral solution.

[0009] In an embodiment, the step of stirring and mixing uniformly the MFHO-alkyl alcohol supramolecular solvent, deionized water and a citrus peel concentrate dilute solution, and then centrifuging to obtain a citral solution further comprises:

[0010] The MFHO-alkyl alcohol, deionized water and a citrus peel concentrate dilute solution are stirred and mixed uniformly, and then centrifuged to obtain a primary solution;

[0011] The primary solution is subjected to fluorine alcohol solution recovery by reduced pressure distillation to obtain a secondary solution.

[0012] The secondary solution is eluted to obtain the citral solution.

[0013] In an embodiment, the ratio of trifluoroacetaldehyde hemiacetal, 2-(trifluoromethoxy)ethanol, 2,2-difluoroethanol, and ethanol is 0.65-0.85:0.3-0.5:1.3-1.9:1.

[0014] In an embodiment, the ratio of the fluoroalcohol and the alkanol is 1:0.08-0.15

[0015] The present application also provides a preparation method of a citral mini-emulsion, comprising a citral solution prepared according to the preparation method of the citral solution of any one of the above, the preparation method of the citral mini-emulsion comprising the following steps:

[0016] Mixing and stirring the citral solution, a copolymerization crosslinking agent, an oily monomer, an initiator, and deionized water to obtain an emulsion A;

[0017] Mixing and low-speed stirring the aqueous monomer and deionized water to obtain a mixed solution B;

[0018] Gradually adding the emulsion A to the mixed solution B, and gradually increasing the temperature to make the emulsion A and the mixed solution B mixed and converted into an emulsion C;

[0019] Adding p-hydroxyanisole to the emulsion C to terminate the reaction, cooling, and collecting to obtain a citral mini-emulsion.

[0020] In an embodiment, the aqueous monomer comprises any one of dimethylaminopropyl acrylamide, (3-acrylamidopropyl)trimethylammonium chloride N-(2-hydroxypropyl) methacrylamide; and / or,

[0021] The oily monomer comprises any one of styrene, butyl acrylate; and / or,

[0022] The copolymerization crosslinking agent comprises any one of sodium vinyl sulfonate, sodium methacrylate hydroxypropyl sulfonate, 1-allyloxy-3-(4-nonylphenol)-2-propanol polyoxyethylene (10) ether ammonium sulfate, sodium allyloxyhydroxypropane sulfonate (HAPS); and / or,

[0023] The initiator comprises 2,2-azobis(2-methylpropylimid) dihydrochloride (AIBA).

[0024] In an embodiment, the ratio of the copolymerization crosslinking agent, the oily monomer, the initiator, the deionized water, and the citral solution is 1-2.5:25-35:0.8-1.8:40-60:2-8.

[0025] In an embodiment, the ratio of the aqueous monomer and the deionized water is 5-9:25-40.

[0026] The application also provides a citral mini-emulsion prepared by the preparation method of the citral mini-emulsion according to any one of the above.

[0027] The application provides a preparation method of a citral solution, which comprises the following steps: preparing a fluorine alcohol mixed solution through supersolution treatment, adding an alkyl alcohol to prepare a fluorine alcohol-alkyl alcohol solution, mixing uniformly through vortexing by adding deionized water, and forming a clear and transparent liquid-liquid two-phase through centrifugal separation, wherein the separated lower phase is an MFHO-alkyl alcohol supramolecular solvent, finally, adding the MFHO-alkyl alcohol and deionized water into a dilute solution of a citrus peel concentrate, mixing uniformly through vortexing, and centrifugal separating, and the yellowish solution in the lower layer is the required citral solution. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a mass spectrum of example one provided by the embodiment scheme of the application.

[0029] Figure 2 is a gas phase diagram of example one provided by the embodiment scheme of the application.

[0030] The implementation, functional features and advantages of the application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0032] It should be noted that if the embodiments of the application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0033] In addition, if the description of "first", "second" and the like is involved in the embodiments of the present application, the description of "first", "second" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can be explicitly or implicitly included at least one of the features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes, for example, "A and / or B" includes A scheme, or B scheme, or A and B scheme. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the scope of protection required by the present application.

[0034] Please refer to Figure 1 The present application provides a preparation method of citral solution, comprising:

[0035] S10, trifluoroacetaldehyde is configured into a fluorine alcohol mixed solution with semi-ethanol, 2-(trifluoromethoxy) ethanol, 2, 2-difluoroethanol and ethanol;

[0036] S20, taking the fluorine alcohol mixed solution, adding alkanol to form a fluorine alcohol-alkanol solution;

[0037] S30, vortex mixing and centrifugal separation of the fluorine alcohol-alkanol solution by adding deionized water, and obtaining MFHO-alkanol supramolecular solvent;

[0038] S40, vortex mixing and centrifugal separation of the MFHO-alkanol supramolecular solvent, deionized water and citrus peel concentrate dilute solution, and obtaining citral solution.

[0039] The present application provides a preparation method of citral solution, by means of supersolution treatment, configuring fluorine alcohol mixed solution, adding alkanol to form fluorine alcohol-alkanol solution, vortex mixing by adding deionized water, and centrifugal separation to form clear and transparent liquid-liquid two-phase, wherein the separated lower phase is MFHO-alkanol supramolecular solvent, and finally adding the MFHO-alkanol supramolecular solvent and deionized water to the citrus peel concentrate dilute solution, vortex mixing and centrifugal separation, and the lower yellow solution is the required citral solution. The extraction method is simple and reliable, and the extraction efficiency is high.

[0040] In step S40, the citral solution obtained after centrifugal separation contains fluorine alcohol solution.

[0041] Further, step S40 further comprises:

[0042] S41, vortexing the MFHO-alkanol supramolecular solvent, deionized water and the dilute solution of citrus peel concentrate, and centrifuging to obtain a primary solution;

[0043] S42, recovering the fluorine alcohol solution by vacuum distillation of the primary solution to obtain a secondary solution.

[0044] S43, eluting the secondary solution to obtain the citral solution.

[0045] In this embodiment, the fluorine alcohol solution is recovered by vacuum distillation, and the citral solution is obtained by elution.

[0046] It should be noted that step S43 includes:

[0047] adding an eluent to the secondary solution;

[0048] adding a silica gel G column elution;

[0049] After removing the eluent, the citral solution is obtained.

[0050] The eluent is petroleum ether / ethyl acetate (9 / 1), and the silica gel G column has a particle size of 60-100 mesh.

[0051] On the other hand, in the embodiments provided by the present application, the ratio of trifluoroacetaldehyde hemiacetal, 2-(trifluoromethoxy)ethanol, 2,2-difluoroethanol and ethanol is 0.65-0.85:0.3-0.5:1.3-1.9:1.

[0052] Similarly, in this embodiment, the ratio of the fluorine alcohol to the alkanol is 1:0.08-0.15

[0053] Based on the above preparation method of citral solution, the present application further provides a preparation method of citral fine emulsion, which comprises the citral solution prepared by the above preparation method of citral solution. The preparation method of citral fine emulsion comprises the following steps:

[0054] S100, mixing and stirring the citral solution, copolymerization crosslinking agent, oily monomer, initiator and deionized water to obtain emulsion A;

[0055] S200, mixing and low-speed stirring the aqueous monomer and deionized water to obtain a mixture B;

[0056] S300, gradually adding the emulsion A to the mixture B, and gradually increasing the temperature to make the emulsion A and the mixture B mix and convert into emulsion C;

[0057] S400, adding p-hydroxyanisole to the emulsion C to terminate the reaction, cooling and collecting to obtain a citral fine emulsion.

[0058] In the present embodiment, the aqueous monomer includes any one of dimethylaminopropyl acrylamide, (3-acrylamidopropyl) trimethylammonium chloride N-(2-hydroxypropyl) methacrylamide.

[0059] Similarly, the oily monomer includes any one of styrene, butyl acrylate.

[0060] Similarly, the copolymerization crosslinking agent includes any one of sodium vinyl sulfonate, sodium methacrylate hydroxypropyl sulfonate, 1-allyloxy-3-(4-nonyl phenol)-2-propanol polyoxyethylene (10) ether ammonium sulfate, sodium allyloxy hydroxy propane sulfonate (HAPS).

[0061] Similarly, the initiator includes 2,2-azobis (2-methylpropyl imid) dihydrochloride (AIBA).

[0062] The above-mentioned aqueous monomer, oily monomer, copolymerization crosslinking agent and initiator can be present alternatively or simultaneously, and are not specifically limited herein.

[0063] On the other hand, the ratio of the copolymerization crosslinking agent, the oily monomer, the initiator, the deionized water and the citral solution is 1-2.5:25-35:0.8-1.8:40-60:2-8.

[0064] In addition, the ratio of the aqueous monomer to the deionized water is 5-9:25-40.

[0065] The present application also provides a citral mini-emulsion, which is prepared by the preparation method of the citral mini-emulsion.

[0066] The citral mini-emulsion is used for repelling mosquitoes. The pure cotton fabric is soaked in the citral mini-emulsion, and then is subjected to double dipping and double rolling, drying, baking, cleaning and drying to obtain a fabric capable of repelling mosquitoes.

[0067] Based on the preparation method of the citral solution, the citral mini-emulsion and the preparation method thereof, the present application provides a specific embodiment:

[0068] Embodiment (I)

[0069] I. Freeze-thaw enzymatic hydrolysis / ion liquid ultrasonic-super solution combined treatment of citrus peel

[0070] Please refer to Figures 1 to 2 , coenzyme and enzyme base

[0071] (1) Coenzyme and enzyme base solution

[0072] Preparation of coenzyme and enzyme base solution: accurately weigh a certain amount of carboxypeptidase, acetylcholinesterase, succinate dehydrogenase, three kinds of coenzyme and enzyme base, respectively dissolved with an appropriate amount of sodium phosphate dibasic-citric acid buffer solution, the concentration is 400 U / mL.

[0073] (2) Coenzyme activator

[0074] Respectively weigh magnesium sulfate, calcium chloride, manganese sulfate, and dissolve with deionized water to prepare a solution of a certain concentration. The concentration of magnesium sulfate solution is 0.25 mol / L, the concentration of calcium chloride solution is 0.05 mol / L, and the concentration of manganese sulfate solution is 0.02 mol / L.

[0075] 2, citrus peel superfine powder

[0076] After washing and removing seeds, the fresh citrus peel is soaked in water, frozen and freeze-dried. The freeze-dried citrus peel is crushed and ground to obtain a coarse powder of the peel, which is sieved through a 40-mesh sieve to remove large particle impurities. The sieved citrus peel powder is frozen in a liquid nitrogen environment for 5 min, then transferred to a cryogenic grinding machine to be ground to a particle size of <50 μm (D90≤50 μm), forming a 40-mesh superfine powder.

[0077] 3, Enzymatic-ultrasonic and ionic liquid treatment of citrus peel superfine powder

[0078] (1) Take 10 grams of citrus peel superfine powder, add buffer solution with pH=6.8 according to the material ratio 1:35, and obtain a citrus peel superfine powder dispersion after high-speed homogenization (20000R / min*15min), add coenzyme and enzyme base in 2, the total concentration is 80 U / mL, to enhance the enzymatic reaction, the ratio of carboxypeptidase, acetylcholinesterase and succinate dehydrogenase is 0.27:0.45:0.28.

[0079] (2) At the same time, add magnesium sulfate at a dosage of 2 mmol / ml, calcium chloride at a dosage of 1.2 mmol / ml, and manganese sulfate at a dosage of 0.2 mmol / ml to activate the enzyme.

[0080] (3) Add the above solution to deionized water to adjust the pH to 4.6, add cellulase (2% w / w) and pectinase (1% w / w) according to the relative mass ratio of citrus peel superfine powder, and enzymatically hydrolyze at 45℃ for 2h. After enzymatic hydrolysis, ultrasonic treatment (40kHz, 600W, 15min) is performed to destroy the cell wall structure and release citral.

[0081] (4) The above enzymatic ultrasonic liquid 200 mL, adding 25 mg / L of 1-(2-hydroxyethyl)-3-methyl imidazole tetrafluoroborate ([ETMIM]BF4) / 1-decyl-3-methyl imidazole hexafluorophosphate ([ATPy]PF6) with [ETMIM]BF4:[ATPy]PF6 being 1.5:2:0.35, adding potassium chloride KCL concentration of 45 g / L, constant temperature stirring, 40°C * 75 min, rotation speed of 300 R / min. After treatment, intermittent 5 min after ultrasonic dispersion (power 200 W, time 15 min), continuous treatment 3 times.

[0082] Centrifugal separation (8000 rpm x 10 min), taking the supernatant was concentrated (35°C, 0.08 MPa) to solid content ≥30%, namely the citrus peel concentrate was obtained.

[0083] 4, Citrus peel concentrate super-solution treatment

[0084] Trifluoroacetaldehyde hemiethanol (abbreviated as TFAAH), 2-(trifluoromethoxy) ethanol (abbreviated as 2TE), 2,2-difluoroethanol (abbreviated as DFE), ethanol were configured into a 70% fluorine alcohol mixed solution (MFHO) in a certain proportion, wherein the ratio of TFAAH:2TE:DFE:ethanol is 0.7:0.4:1.6:1.

[0085] Take the above fluorine alcohol 10 g, add dodecanol (DO) to form a fluorine alcohol-alkanol solution, fluorine alcohol:alkanol is 1:0.08.

[0086] The above fluorine alcohol-alkanol solution is added to a certain amount of deionized water, and vortexed in a centrifuge tube (200 R / min, 50 s), centrifugal separation (3000 rpm x 20 min), the system can form a clear and transparent liquid-liquid two-phase, and the lower phase separated out is the MFHO-alkanol supermolecular solvent.

[0087] Take 5 g of the citrus peel concentrate in 4, add deionized water to 1 L, and obtain a dilute solution after homogenization (20000 R / min*15 min).

[0088] Take 10 ml of the above dilute solution, add 35 ml of MFHO-alkanol and a certain amount of deionized water to ensure the total amount of the solution is 50 ml, vortex (200 R / min, 10 s) and centrifugal separation (8000 rpm x 10 min), and the lower yellow solution is the desired solution. After vacuum distillation, the temperature is 55°C, and the vacuum degree is 0.09 MPa, and the fluorine alcohol solution is recovered.

[0089] The solution of the reduced pressure distillation was added with an eluent: petroleum ether / ethyl acetate (9 / 1), and was subjected to column chromatography with silica gel G (80 mesh) for 60 min. After removal of the eluent, a solution of citral was obtained.

[0090] II. Preparation of citral emulsion

[0091] 1. The copolymerization crosslinking agent, oily monomer, initiator, deionized water and citral were added into a beaker in a certain proportion, and low-speed stirring (200 R / min, 10 min) was performed to obtain emulsion A for use;

[0092] The proportion of the crosslinking agent, oily monomer, initiator, deionized water and citral was 1.5:25:0.8:40:2.

[0093] 2. A certain amount of aqueous monomer and deionized water were added into a three-necked flask in a certain proportion, and low-speed stirring (200 R / min*5 min) was performed. The emulsion A was gradually added dropwise into the three-necked flask by using a peristaltic pump (pump speed, 10 mL / min), and the addition was completed within 15 min. At the same time, the temperature was gradually increased (1 ℃ / min) to 60 ℃. After the liquid in the three-necked flask was completely converted into an emulsion, the stirring speed was adjusted to 500 R / min, and the temperature was increased to 85 ℃ for 10 h. After the reaction was completed, 0.05 g of p-hydroxyanisole was added to terminate the reaction, and the temperature was decreased to obtain the citral emulsion.

[0094] The proportion of the aqueous monomer and deionized water was 5:40.

[0095] 3. The aqueous monomer was (3-acrylamidopropyl) trimethylammonium chloride N-(2-hydroxypropyl) methacrylamide; the oily monomer was styrene; the copolymerization crosslinking agent was sodium 2-hydroxypropyl sulfonate methacrylate (AMPS-Na); and the initiator was 2,2-azobis(2-methylpropylimino) dihydrochloride (AIBA).

[0096] III. Application of citral mini-emulsion to mosquito-repelling finishing

[0097] 5 g of pure cotton fabric was immersed in 200 ml of citral mini-emulsion at 40 ℃ for 15 min, and was subjected to double immersion and double padding (pad rate 80%) and drying (temperature 80 ℃) and baking (135 ℃, time 90 s) and washing and drying.

[0098] IV. Performance characterization and results

[0099] (1) Particle size and morphology

[0100] The average particle size D50 of the mini-emulsion was about 400 nm, which was measured by dynamic light scattering.

[0101] (2) Mosquito-repelling performance

[0102] The mosquito repellent rate of D-limonene released from the lemon aldehyde microemulsion reached 90% (within 2h) through Y-type olfactometer test.

[0103] (3) Sustained-release property

[0104] The textile mosquito repellent release experiment showed that the cumulative release rate of the lemon aldehyde microemulsion finished pure cotton fabric reached 72% within 12h, meeting the sustained-release requirement.

[0105] Gas chromatography-mass spectrometry analysis showed that the retention time was 6.05 for D-limonene, and the peak area reached 32%; the retention time was 9.53 for lemon aldehyde, and the peak area reached 64.5%. It was indicated that the main component of the extract was lemon aldehyde.

[0106] Example (two)

[0107] I. Freeze-thaw-enzymatic / ionic liquid ultrasonic-super solution combined treatment of citrus peel

[0108] 1. Coenzyme and enzyme base

[0109] (1) Coenzyme and enzyme base solution

[0110] Prepare the coenzyme and enzyme base solution: accurately weigh a certain amount of carboxypeptidase, acetylcholinesterase, and succinate dehydrogenase, three kinds of coenzymes and enzyme bases, respectively, and dissolve them in an appropriate amount of disodium hydrogen phosphate-citric acid buffer to a concentration of 600 U / mL.

[0111] (2) Coenzyme activator

[0112] Weigh magnesium sulfate, calcium chloride, and manganese sulfate respectively, dissolve them in deionized water to prepare a solution with a certain concentration. The concentration of magnesium sulfate solution is 0.5 mol / L, the concentration of calcium chloride solution is 0.2 mol / L, and the concentration of manganese sulfate solution is 0.05 mol / L.

[0113] 2. Citrus peel ultrafine powder

[0114] After washing and removing seeds, the fresh citrus peel was soaked in water, frozen, and then freeze-dried. The freeze-dried citrus peel was crushed and ground, and the coarse powder was obtained by passing through a 40-mesh sieve to remove large particle impurities. The sieved citrus peel powder was frozen in liquid nitrogen for 5 min, then transferred to a cryogenic grinder to be ground to a particle size of <50 μm (D90≤50 μm), forming an 800-mesh ultrafine powder.

[0115] 3. Enzymatic-ultrasonic and ionic liquid treatment of citrus peel ultrafine powder

[0116] (1) Take 10 grams of citrus peel superfine powder, add a buffer solution with pH = 7.2 according to the material ratio 1:45, and after high-speed homogenization (20000R / min*15min), obtain a citrus peel superfine powder dispersion, add coenzymes and enzyme bases in 2, add a total concentration of 40-120U / mL to enhance the enzymatic reaction, and the ratio of carboxypeptidase, acetylcholinesterase, and succinate dehydrogenase is 0.32:0.43:0.25.

[0117] (2) At the same time, add magnesium sulfate at an addition amount of 3mmol / ml, calcium chloride at 1.8mmol / ml, and manganese sulfate at 0.35mmol / ml for enzyme activation.

[0118] (3) Add the above solution to deionized water to adjust the pH to 4.4, add cellulase (2% w / w) and pectinase (1% w / w) according to the relative mass ratio of citrus peel superfine powder, and enzymatically hydrolyze at 45℃ for 2h. After enzymatic hydrolysis, ultrasonic treatment (40kHz, 600W, 15min) is performed to destroy the cell wall structure and release citral.

[0119] (4) Add 1-(2-hydroxyethyl)-3-methylimidazole tetrafluoroborate ([ETMIM]BF4) / 1-decyl-3-methylimidazole hexafluorophosphate ([ATPy]PF6) with a concentration of 24mg / L to the above enzymatic ultrasonic liquid 200mL, wherein [ETMIM]BF4:[ATPy]PF6 is 1.5:1:0.35, add potassium chloride KCL with a concentration of 60g / L, constant temperature stirring, 70℃*60min, and the rotation speed is 500R / min. After treatment, intermittent ultrasonic dispersion (power 400W, time 12min) is performed for 5min, and continuous treatment is performed for 3 times.

[0120] Centrifugal separation (8000rpm*10min), take the supernatant and concentrate (35℃, 0.08MPa) under reduced pressure to obtain a citrus peel concentrate with a solid content of ≥30%.

[0121] 4. Citrus peel concentrate super-solution treatment

[0122] Trifluoroacetaldehyde hemiethanol (abbreviated as TFAAH), 2-(trifluoromethoxy)ethanol (abbreviated as 2TE), 2,2-difluoroethanol (abbreviated as DFE), and ethanol are configured into a 70% fluorine alcohol mixed solution (MFHO) according to a certain ratio, wherein the ratio of TFAAH:2TE:DFE:ethanol is 0.65:0.4:1.4:1.

[0123] Take 10g of the above fluorine alcohol and add dodecanol (DO) to configure a fluorine alcohol-alkanol solution, and the ratio of fluorine alcohol to alkanol is 1:0.15.

[0124] The above fluorine alcohol-alkanol solution is added to a certain amount of deionized water, stirred in a centrifuge tube (400 R / min, 30 s), and centrifuged (2000 rpm x 30 min) to form a clear and transparent liquid-liquid two-phase system, and the separated lower phase is the MFHO-alkanol supramolecular solvent.

[0125] Take 5 g of the citrus peel concentrate in 4, add deionized water to 1 L, homogenize (20000 R / min*15 min) to obtain a dilute solution.

[0126] Take 10 ml of the above dilute solution, add 25 ml of MFHO-alkanol and a certain amount of deionized water to ensure that the total amount of the solution is 50 ml, stir (400 R / min, 10 s) and centrifuge (8000 rpm x 10 min) to obtain the lower yellow solution.

[0127] The solution obtained by vacuum distillation is added with an eluent: petroleum ether / ethyl acetate (9 / 1), and then passed through a silica gel G (particle size 60 mesh) chromatographic column and eluted for 45 min. After removing the eluent, a citral solution is obtained.

[0128] II. Preparation of citral emulsion

[0129] 1. The copolymerization crosslinking agent, oily monomer, initiator, deionized water and citral are added to a beaker in proportion, stirred at low speed (200-400 R / min, 5-10 min) to obtain emulsion A for use;

[0130] The proportion of crosslinking agent, oily monomer, initiator, deionized water and citral is 1-2.5:25-35:0.8-1.8:40-60:2-8.

[0131] 2. A certain amount of aqueous monomer and deionized water are added to a three-necked flask in proportion, stirred at low speed (200 R / min*5 min), and emulsion A is gradually added to the three-necked flask by peristaltic pump (pump speed, 5 mL / min), which is completed within 20 min; at the same time, gradually increase the temperature (1 ℃ / min) to 60 ℃, and after the liquid in the three-necked flask is completely converted into emulsion, adjust the speed to (600 R / min) and increase the temperature to 90 ℃ for 8 h. After the reaction is completed, 0.05-0.1 g of p-hydroxyanisole is added to terminate the reaction, and the product is obtained after cooling.

[0132] Among them, the proportion of aqueous monomer and deionized water is 9:40.

[0133] 3. Water-based monomer: dimethylaminopropyl acrylate; oil-based monomer: styrene, butyl acrylate; copolymerization crosslinking agent: sodium allyloxy hydroxy propane sulfonate (HAPS); initiator: 2,2-azobis(2-methylpropylimid) dihydrochloride (AIBA).

[0134] III. Citral miniemulsion for mosquito-repellent finishing

[0135] Take 5 g of pure cotton fabric, soak in citral miniemulsion 200 ml, 40 °C * 25 min, double-dip double-roller (roller rate 80%), dry (temperature 80 °C), baking (120 °C, time 180 s), wash, dry.

[0136] IV. Performance characterization and results

[0137] (1) Particle size and morphology

[0138] The average particle size of the miniemulsion is D50 ≈ 200 nm measured by dynamic light scattering.

[0139] (2) Mosquito-repellent performance

[0140] Through Y-type olfactometer testing, the mosquito-repellent rate of D-limonene released by the citral microemulsion reaches 90% (within 2 h).

[0141] (3) Slow-release characteristics

[0142] Textile mosquito-repellent release experiments show that the cumulative release rate of citral microemulsion finished pure cotton fabric is 72% within 12 h, meeting the slow-release requirements.

Claims

1. A method for preparing a citral solution, characterized by, The method comprises the following steps: configuring trifluoroacetaldehyde hemiacetal, 2-(trifluoromethoxy) ethanol, 2,2-difluoroethanol and ethanol into a fluorine alcohol mixed solution; adding an alkyl alcohol into the fluorine alcohol mixed solution to obtain a fluorine alcohol-alkyl alcohol solution; adding deionized water into the fluorine alcohol-alkyl alcohol solution and stirring to obtain an MFHO-alkyl alcohol supermolecular solution; stirring the MFHO-alkyl alcohol supermolecular solution, deionized water and a dilute solution of citrus peel concentrate, and centrifuging to obtain a citral solution.

2. The method of preparing a citral solution according to claim 1, characterized in that, The step of stirring the MFHO-alkyl alcohol supermolecular solution, deionized water and a dilute solution of citrus peel concentrate, and centrifuging to obtain a citral solution further comprises: stirring the MFHO-alkyl alcohol supermolecular solution, deionized water and a dilute solution of citrus peel concentrate, and centrifuging to obtain a primary solution; performing fluorine alcohol solution recovery on the primary solution by reduced pressure distillation to obtain a secondary solution. eluting the secondary solution to obtain the citral solution.

3. The method of claim 1, wherein the citral solution is prepared by, The ratio of trifluoroacetaldehyde hemiacetal, 2-(trifluoromethoxy) ethanol, 2,2-difluoroethanol and ethanol is 0.65-0.85:0.3-0.5:1.3-1.9:

1.

4. The method of claim 1, wherein the citral solution is prepared by, The ratio of the fluorine alcohol to the alkyl alcohol is 1:0.08-0.

15.

5. A method of preparing a citral miniemulsion, characterized in that The method for preparing a citral solution according to any one of claims 1 to 4, wherein the method for preparing the citral solution comprises the following steps: mixing the citral solution, a copolymerization crosslinking agent, an oily monomer, an initiator and deionized water to obtain an emulsion A; mixing an aqueous monomer and deionized water at a low speed to obtain a mixed solution B; gradually adding the emulsion A into the mixed solution B, and gradually increasing the temperature to make the emulsion A and the mixed solution B mix and transform into an emulsion C; adding p-hydroxyanisole into the emulsion C to terminate the reaction, and cooling and collecting to obtain a citral fine emulsion.

6. The method for preparing a citral miniemulsion according to claim 5, characterized in that, The aqueous monomer comprises any one of dimethylaminopropyl acrylamide, (3-acrylamidopropyl) trimethylammonium chloride N-(2-hydroxypropyl) methacrylamide; and / or, The oily monomer comprises any one of styrene, butyl acrylate; and / or, The copolymerization crosslinking agent comprises any one of vinyl sulfonic acid sodium, sodium methacrylate hydroxypropyl sulfonate, 1-allyloxy-3-(4-nonyl phenol)-2-propanol polyoxyethylene (10) ether ammonium sulfate, sodium allyloxy hydroxy propane sulfonate (HAPS); and / or, The initiator comprises 2,2-azobis(2-methylpropylimid) dihydrochloride (AIBA).

7. The method for preparing a citral miniemulsion according to claim 5, characterized in that, The ratio of the copolymerization crosslinking agent, the oily monomer, the initiator, the deionized water and the citral solution is 1-2.5:25-35:0.8-1.8:40-60:2-8.

8. The method for preparing a citral miniemulsion according to claim 5, characterized by, The ratio of the aqueous monomer to the deionized water is 5-9:25-40.

9. A citral mini-emulsion characterized in that, The citral fine emulsion prepared by the method for preparing a citral fine emulsion according to any one of claims 5 to 8.

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