A Refining Method for Natural Eucalyptus Oil and Its Application

Abstract

This invention discloses a refining method for natural eucalyptus oil and its application, relating to the field of plant essential oil refining technology; specifically including the following steps: S1: Add natural eucalyptus oil and zeolite to a distillation kettle, and perform total reflux sequentially under vacuum conditions; adjust the reflux ratio, perform one reflux, collect the distillate as the head fraction; adjust the reflux ratio, perform a second reflux, collect the distillate, and obtain refined eucalyptus oil A; S2: Pack the packing material into a chromatography purification column; load the refined eucalyptus oil A into the chromatography purification column for circulating chromatography, obtain the eluent, and remove the ethanol by vacuum distillation to obtain refined eucalyptus oil; dispense and package to obtain the product; this product can be applied in the pharmaceutical industry and fragrance industry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plant essential oil refining, in particular to a refining method of natural eucalyptus oil and application thereof. BACKGROUND

[0002] Natural eucalyptus oil, also known as eucalyptus oil, is a colorless to light yellow clear liquid with a special aromatic smell similar to camphor, a pungent and cool taste, almost insoluble in water, and easily soluble in ethanol. It has a wide range of uses and can be used in the pharmaceutical industry, spices, and food industry. It is mainly obtained from the leaves and twigs of plants in the Myrtaceae family, such as Eucalyptus globulus or plants in the Lauraceae family, such as Cinnamomum camphora. The commonly used extraction methods are distillation, extraction, and cold pressing. The main component of the extracted crude eucalyptus oil is 1,8-cineole, and the impurities are mainly a small amount of aldehydes, terpenes and their oxygen derivatives.

[0003] The refining of natural eucalyptus oil is mainly to extract 1,8-cineole, which has the problems of heat sensitivity and a large number of impurities in the raw materials. The refining methods include reduced pressure distillation and chromatographic column separation. The reduced pressure distillation method is convenient to operate and has high efficiency. By reducing the boiling point under reduced pressure, the target product can be prevented from decomposing, which is helpful for extracting the target product from complex mixtures. However, it is difficult to separate substances with close boiling points, resulting in a decrease in purity. The chromatographic column separation method can achieve high-purity separation, but the cost is high, and the adsorption groups in the packing material of the chromatographic column have poor stability, which can easily fall off during the elution process, resulting in a decrease in product purity.

[0004] In summary, in order to solve the above problems, it is of great significance to provide a refining method of natural eucalyptus oil and application thereof. SUMMARY

[0005] The purpose of the present application is to provide a refining method of natural eucalyptus oil and application thereof to solve the problems in the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] A refining method of natural eucalyptus oil, comprising the following steps:

[0008] S1: adding natural eucalyptus oil and zeolite into a distillation kettle, and sequentially performing full reflux under vacuum conditions; adjusting the reflux ratio, once refluxing, collecting the distillate as the head; adjusting the reflux ratio, twice refluxing, collecting the distillate to obtain refined eucalyptus oil A;

[0009] S2: loading the packing material into a chromatographic purification column; loading the refined eucalyptus oil A into the chromatographic purification column for cyclic chromatography to obtain an eluent; evaporating ethanol under reduced pressure to obtain refined eucalyptus oil; and packaging to obtain the product.

[0010] More preferably, the reflux ratio in the first refluxing process is 20-22:1.

[0011] More preferably, the reflux ratio in the second refluxing process is 10-12:1.

[0012] More preferably, the vacuum degree in the full refluxing process is 4000-5000 Pa, and the time is 50-60 min.

[0013] More preferably, the diameter-height ratio of the filler in the chromatographic purification column is 1:8-10, and the eluent in the circulating chromatography is anhydrous ethanol.

[0014] More preferably, the preparation method of the filler comprises the following steps:

[0015] (1) dispersing the nanoporous silica in 60% anhydrous ethanol solution, adding 3-(isobutenoyloxy) propyl trimethoxysilane, stirring at 40-45℃ for 5-6h, filtering, washing, and drying to obtain an alkenyl-modified filler;

[0016] (2) dispersing the alkenyl-modified filler in deionized water, adding mercaptoacetic acid and azobisisobutyronitrile, stirring at 40-45℃ under ultraviolet light for 2-4h, filtering and washing, and drying to obtain a carboxyl-modified filler;

[0017] (3) adding the carboxyl-modified filler into anhydrous ether, stirring uniformly, adding 4-amino phthalimide and an activator, stirring at 50-60℃ for 3-4h to obtain a phthalimide-modified filler;

[0018] (4) mixing tetrachlorophthalic anhydride, urea, and ammonium molybdate uniformly, heating and melting, adding zinc acetate and the phthalimide-modified filler, stirring at 210-220℃ for 6-7h, cooling, crushing, washing with 60% ethanol aqueous solution, filtering, and drying to obtain the filler.

[0019] The alkenyl-modified filler comprises the following raw materials by mass fraction: 9-10 parts of nanoporous silica, 40-50 parts of 60% anhydrous ethanol solution, and 1-1.5 parts of 3-(isobutenoyloxy) propyl trimethoxysilane.

[0020] The carboxyl-modified filler comprises the following raw materials by mass fraction: 4-6 parts of the alkenyl-modified filler, 40-50 parts of deionized water, 0.2-0.3 parts of mercaptoacetic acid, and 0.05-0.1 parts of azobisisobutyronitrile.

[0021] The phthalimide-modified filler comprises the following raw materials by mass fraction: 4-6 parts of the carboxyl-modified filler, 30-40 parts of anhydrous ether, 0.3-0.4 parts of 4-amino phthalimide, and 0.5-0.6 parts of an activator.

[0022] The filler comprises the following mass parts of raw materials: 1.8-2 parts of tetrachlorophthalic anhydride, 18-20 parts of urea, 0.1-0.2 parts of ammonium molybdate, 4-6 parts of phthalimide modified filler.

[0023] The product obtained by the refining method of the natural eucalyptus oil can be applied to the pharmaceutical industry, spices.

[0024] More preferably, the activating agent is 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide and N-hydroxysuccinimide in a mass ratio of 1:1-1.5.

[0025] Compared with the prior art, the application has the following beneficial effects:

[0026] (1) The main component of the natural eucalyptus oil is 1,8-eucalyptol, and the boiling point under normal pressure is 178℃. The main impurities are α-pinene, limonene, γ-terpinene, α-terpineol, etc. Among them, the boiling point of limonene under normal pressure is 177℃, and the boiling point difference with 1,8-eucalyptol is only 1℃. It is difficult to improve the purity by single vacuum distillation. In the present application, intermittent vacuum distillation is used first, and the reflux ratio is adjusted to remove low-boiling-point impurities such as α-pinene. 1,8-eucalyptol containing limonene impurities is collected, and then a chromatographic purification column is used to further remove limonene and improve the purity of the product.

[0027] (2) The filler of the chromatographic purification column in the present application is nano-porous silica, which has more adsorption sites, so it can fix more impurities, improve the separation efficiency, and has excellent high-temperature resistance and corrosion resistance, and good stability. In the present application, an alkenyl silane coupling agent is introduced into the filler, and a mercapto acid is grafted, so as to react with 4-amino phthalimide to introduce a phthalimide structure. Under urea, ammonium molybdate and zinc acetate, tetrachlorophthalic anhydride reacts to form a filler containing nickel phthalocyanine structure. Nickel ions are transition metal ions, which have an unfilled d orbital, can overlap with the π electron cloud of limonene substances, and form a π-metal coordination bond, so as to realize the fixation of limonene substances. The phthalocyanine nickel structure has better stability than the complex formed by the amino group and the nickel ion, and is not easy to break due to high temperature, so as to lose the fixation effect, thereby improving the stability. The chlorine on the tetrachlorophthalic anhydride becomes a substituent group of the phthalocyanine nickel structure, which also has the effect of forming a coordination bond with the π electron cloud of limonene substances, thereby enhancing the fixation effect and improving the separation degree. DETAILED DESCRIPTION

[0028] All other embodiments obtained by a person of ordinary skill in the art without making creative labor based on the embodiments in the present application belong to the scope of protection of the present application.

[0029] It should be noted that the purchase of all raw materials involved in the present application has no special restrictions, and exemplary raw materials include: nanoporous silica with a particle size of 70-100 nm, provided by Hangzhou Xinqiao Biotechnology Co., Ltd.; 3-(isobutenoyloxy) propyl trimethoxysilane, CAS number: 2530-85-0; mercaptoacetic acid, CAS: 68-11-1; 4-amino phthalimide, CAS number: 3676-85-5; tetrachlorophthalic anhydride, CAS number: 117-08-8; urea, CAS number: 57-13-6; zinc acetate, dihydrate and zinc acetate, CAS number: 5970-45-6.

[0030] More preferably, in the following examples, parts are mass parts, and the above-mentioned raw materials and the following examples and comparative examples use commercially available raw materials but do not mention the raw materials.

[0031] More preferably, the preparation method of the natural eucalyptus oil comprises the following steps: drying fresh blue gum leaves, crushing to 20-80 mesh, and adding deionized water to a distillation container at a mass ratio of 1:6, keeping the heating at a slight boil for 8 h, collecting the distillation liquid, separating the water layer, extracting, rotary evaporation to evaporate the extractant, and removing water to obtain the natural eucalyptus oil.

[0032] Example 1: Step 1: Preparation of filler

[0033] (1) 10 parts of nanoporous silica were dispersed in 45 parts of 60% anhydrous ethanol solution, 1 part of 3-(isobutenoyloxy) propyl trimethoxysilane was added, stirred at 45°C for 5h, filtered, washed and dried to obtain an alkenyl-modified filler;

[0034] (2) 5 parts of the alkenyl-modified filler were added to 45 parts of deionized water and dispersed uniformly, 0.25 parts of mercaptoacetic acid and 0.05 parts of azobisisobutyronitrile were added, and stirred at 45°C for 3h under ultraviolet light, filtered, washed and dried to obtain a carboxyl-modified filler;

[0035] (3) 5 parts of the carboxyl-modified filler were added to 35 parts of anhydrous ether and stirred uniformly, 0.35 parts of 4-amino phthalimide and 0.5 parts of activator were added, and stirred at 55°C for 3.5h to obtain a phthalimide-modified filler;

[0036] (4) 1.9 parts of tetrachlorophthalic anhydride, 20 parts of urea, and 0.1 parts of ammonium molybdate were mixed uniformly, heated and melted, 0.9 parts of zinc acetate and 5 parts of phthalimide-modified filler were added, and stirred at 210°C for 6h, cooled, crushed, washed with 60% ethanol aqueous solution, filtered and dried to obtain the filler;

[0037] Step 2: Refining of natural eucalyptus oil

[0038] S1: The natural eucalyptus oil and zeolite were added to the distillation kettle, the vacuum pump was opened, and the vacuum degree was 4000 Pa. The whole reflux was carried out for 60 min. The reflux ratio was adjusted to 20:1, and the first reflux was collected as the head. The reflux ratio was adjusted to 12:1, and the second reflux was collected to obtain refined eucalyptus oil A;

[0039] S2: The filler was loaded into the chromatographic purification column at a diameter-height ratio of 1:9. The refined eucalyptus oil A was loaded into the chromatographic purification column for cycle chromatography to obtain an eluent. The ethanol was distilled off under reduced pressure to obtain refined eucalyptus oil. The product was obtained by packaging after packaging and packaging.

[0040] Example 2: Step one: preparation of the filler:

[0041] (1) 10 parts of nanoporous silica were dispersed in 45 parts of 60% anhydrous ethanol solution, 1 part of 3-(isobutenoyloxy)propyl trimethoxysilane was added, and stirring was carried out at 45°C for 5h. Filtration, washing and drying were carried out to obtain an alkenyl-modified filler;

[0042] (2) 5 parts of the alkenyl-modified filler were added to 45 parts of deionized water and dispersed uniformly. 0.25 parts of mercaptoacetic acid and 0.05 parts of azobisisobutyronitrile were added, and stirring was carried out at 45°C for 3h under ultraviolet light irradiation. Filtration, washing and drying were carried out to obtain a carboxyl-modified filler;

[0043] (3) 5 parts of the carboxyl-modified filler were added to 35 parts of anhydrous ether and stirred uniformly. 0.35 parts of 4-amino phthalimide and 0.5 parts of an activator were added, and stirring was carried out at 55°C for 3.5h to obtain a phthalimide-modified filler;

[0044] (4) 1.9 parts of tetrachlorophthalic anhydride, 20 parts of urea, and 0.1 parts of ammonium molybdate were mixed uniformly and heated to melt. 0.9 parts of zinc acetate and 5 parts of the phthalimide-modified filler were added, and stirring was carried out at 210°C for 6h. After cooling, crushing was carried out. The filler was obtained by washing with 60% ethanol aqueous solution, filtration and drying;

[0045] Step two: refining of the natural eucalyptus oil:

[0046] S1: The natural eucalyptus oil and zeolite were added to the distillation kettle, the vacuum pump was opened, and the vacuum degree was 4000 Pa. The whole reflux was carried out for 60 min. The reflux ratio was adjusted to 20:1, and the first reflux was collected as the head. The reflux ratio was adjusted to 12:1, and the second reflux was collected to obtain refined eucalyptus oil A;

[0047] S2: The filler was loaded into the chromatographic purification column at a diameter-height ratio of 1:8. The refined eucalyptus oil A was loaded into the chromatographic purification column for cycle chromatography to obtain an eluent. The ethanol was distilled off under reduced pressure to obtain refined eucalyptus oil. The product was obtained by packaging after packaging and packaging.

[0048] Example 3: Step one: preparation of the filler:

[0049] (1) Disperse 10 parts of nanoporous silica in 45 parts of 60% anhydrous ethanol solution, add 1 part of 3-(isobutenoyloxy)propyltrimethoxysilane, stir at 45℃ for 5h, filter, wash, and dry to obtain alkenyl modified filler.

[0050] (2) 5 parts of alkenyl modified filler were added to 45 parts of deionized water and dispersed evenly. 0.25 parts of mercaptoacetic acid and 0.05 parts of azobisisobutyronitrile were added. The mixture was stirred at 45°C for 3 hours under ultraviolet light irradiation. After filtration, washing, and drying, carboxyl modified filler was obtained.

[0051] (3) Add 5 parts of carboxyl-modified filler to 35 parts of anhydrous diethyl ether and stir evenly. Add 0.35 parts of 4-aminophthalimide and 0.5 parts of activator and stir at 55°C for 3.5 h to obtain phthalimide-modified filler.

[0052] (4) Mix 1.9 parts tetrachlorophthalic anhydride, 20 parts urea, and 0.1 parts ammonium molybdate evenly, heat to melt, add 0.9 parts zinc acetate and 5 parts phthalimide modified filler, stir at 210℃ for 6 hours, cool, crush, wash with 60% ethanol aqueous solution, filter, and dry to obtain the filler;

[0053] Step Two: Refining Natural Eucalyptus Oil

[0054] S1: Add natural eucalyptus oil and zeolite to the distillation vessel, turn on the vacuum pump, and reflux for 60 minutes under a vacuum of 5000 Pa; adjust the reflux ratio to 22:1, reflux once, collect the distillate as the head fraction; adjust the reflux ratio to 12:1, reflux twice, collect the distillate, and obtain refined eucalyptus oil A.

[0055] S2: The packing material is packed into the chromatography purification column at a diameter-to-height ratio of 1:10; refined eucalyptus oil A is loaded into the chromatography purification column for cyclic chromatography to obtain the eluent. The ethanol is removed by vacuum distillation to obtain refined eucalyptus oil; it is then dispensed and packaged to obtain the product.

[0056] Comparative Example 1: Based on Example 1, only vacuum distillation was performed, with the remaining processes unchanged, as follows: Step 1: Refining of natural eucalyptus oil:

[0057] S1: Add natural eucalyptus oil and zeolite to a distillation vessel, turn on the vacuum pump, and reflux for 60 minutes at a vacuum of 4000 Pa. Adjust the reflux ratio to 20:1, reflux once, and collect the distillate as the head fraction. Adjust the reflux ratio to 12:1, reflux twice, and collect the distillate to obtain refined eucalyptus oil. Dispense and package to obtain the product.

[0058] Comparative Example 2: Based on Example 1, only chromatography column separation was used, with the remaining processes unchanged, as follows: Step 1: Preparation of packing material:

[0059] (1) Disperse 10 parts of nanoporous silica in 45 parts of 60% anhydrous ethanol solution, add 1 part of 3-(isobutenoyloxy)propyltrimethoxysilane, stir at 45℃ for 5h, filter, wash, and dry to obtain alkenyl modified filler.

[0060] (2) 5 parts of alkenyl modified filler were added to 45 parts of deionized water and dispersed evenly. 0.25 parts of mercaptoacetic acid and 0.05 parts of azobisisobutyronitrile were added. The mixture was stirred at 45°C for 3 hours under ultraviolet light irradiation. After filtration, washing, and drying, carboxyl modified filler was obtained.

[0061] (3) Add 5 parts of carboxyl-modified filler to 35 parts of anhydrous diethyl ether and stir evenly. Add 0.35 parts of 4-aminophthalimide and 0.5 parts of activator and stir at 55°C for 3.5 h to obtain phthalimide-modified filler.

[0062] (4) Mix 1.9 parts tetrachlorophthalic anhydride, 20 parts urea, and 0.1 parts ammonium molybdate evenly, heat to melt, add 0.9 parts zinc acetate and 5 parts phthalimide modified filler, stir at 210℃ for 6 hours, cool, crush, wash with 60% ethanol aqueous solution, filter, and dry to obtain the filler;

[0063] Step Two: Refining Natural Eucalyptus Oil

[0064] S1: The packing material is packed into the chromatography purification column with a diameter-to-height ratio of 1:9; refined eucalyptus oil A is loaded into the chromatography purification column for circulating chromatography to obtain the eluent. The ethanol is removed by vacuum distillation to obtain refined eucalyptus oil; it is then dispensed and packaged to obtain the product.

[0065] Comparative Example 3: Based on Example 1, commercially available silica gel was used as the packing material in the chromatography column, and the remaining processes remained unchanged, as follows: Step 1: Refining of natural eucalyptus oil:

[0066] S1: Add natural eucalyptus oil and zeolite to the distillation kettle, turn on the vacuum pump, and reflux for 60 minutes under a vacuum of 4000 Pa; adjust the reflux ratio to 20:1, reflux once, collect the distillate as the head fraction; adjust the reflux ratio to 12:1, reflux twice, collect the distillate, and obtain refined eucalyptus oil A.

[0067] S2: Pack silica gel into a chromatography column with a diameter-to-height ratio of 1:9; load refined eucalyptus oil A into the chromatography column for cyclic chromatography to obtain the eluent; remove ethanol by vacuum distillation to obtain refined eucalyptus oil; dispense and package to obtain the product.

[0068] Comparative Example 4: Based on Example 1, the chromatography column packing used in Example 1 was cleaned and reused, with the rest of the process remaining unchanged, as follows: Step 1: Preparation of packing: The packing used in Example 1 was washed with anhydrous ethanol at 65°C and dried to obtain the packing of Comparative Example 4.

[0069] Step Two: Refining Natural Eucalyptus Oil

[0070] S1: Add natural eucalyptus oil and zeolite to the distillation kettle, turn on the vacuum pump, and reflux for 60 minutes under a vacuum of 4000 Pa; adjust the reflux ratio to 20:1, reflux once, collect the distillate as the head fraction; adjust the reflux ratio to 12:1, reflux twice, collect the distillate, and obtain refined eucalyptus oil A.

[0071] S2: The packing material of Comparative Example 4 was packed into a chromatography purification column with a diameter-to-height ratio of 1:9; refined eucalyptus oil A was loaded into the chromatography purification column for cyclic chromatography to obtain the eluent. The ethanol was removed by vacuum distillation to obtain refined eucalyptus oil; it was dispensed and packaged to obtain the product.

[0072] Performance testing: The purity and yield of each embodiment and comparative example were measured and calculated. The experimental data are shown in Table 1.

[0073] Table 1

[0074]

[0075]

[0076] Conclusion: As shown in Table 1, Comparative Example 1 only used vacuum distillation, resulting in a higher yield, but the purity was lower than that of Example 1; Comparative Example 2 only used chromatography column separation, which required the separation of many impurities, leading to a lower yield; Comparative Example 3 used silica gel as the packing material in the chromatography column, resulting in poor separation and decreased purity; Comparative Example 4 used the cleaned packing material from Example 1, and the purity and yield did not change significantly, indicating that the packing material prepared in this invention can be reused and has good stability.

[0077] In summary, this invention successfully provides a refining method for natural eucalyptus oil by combining vacuum distillation and column chromatography, resulting in a product with high purity. Furthermore, the packing material used in the prepared column chromatography exhibits good stability and adsorption performance.

[0078] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of refining natural eucalyptus oil, characterized by, It comprises the following steps: S1: add natural eucalyptus oil and zeolite into a distillation kettle, and sequentially perform full reflux under vacuum conditions; adjust the reflux ratio, perform once reflux, collect the fraction as a head; adjust the reflux ratio, perform twice reflux, collect the fraction, and obtain refined eucalyptus oil A; S2: load the filler into a chromatographic purification column; load refined eucalyptus oil A into the chromatographic purification column for cycle chromatography, to obtain an eluent, evaporate ethanol under reduced pressure, and obtain refined eucalyptus oil; package, and obtain the product; In the process of the once reflux, the reflux ratio is 20-22:1; In the process of the twice reflux, the reflux ratio is 10-12:1; The preparation method of the filler comprises the following steps: (1) disperse nano-porous silicon dioxide in 60% anhydrous ethanol solution, add 3-(isobutenyl) propyl trimethoxysilane, stir at 40-45℃ for 5-6h, filter, wash, and dry, to obtain an alkenyl-modified filler; (2) disperse the alkenyl-modified filler in deionized water, add mercaptoacetic acid and azobisisobutyronitrile, stir at 40-45℃ under ultraviolet light irradiation for 2-4h, filter and wash, and dry, to obtain a carboxyl-modified filler; (3) disperse the carboxyl-modified filler in anhydrous ether, add 4-amino phthalimide and an activator, stir at 50-60℃ for 3-4h, to obtain a phthalimide-modified filler; (4) mix tetrachlorophthalic anhydride, urea, and ammonium molybdate uniformly, heat and melt, add zinc acetate and the phthalimide-modified filler, stir at 210-220℃ for 6-7h, cool, crush, wash with 60% ethanol aqueous solution, filter, and dry, to obtain the filler.

2. A method of refining natural eucalyptus oil according to claim 1, characterized by: In the process of the full reflux, the vacuum degree is 4000-5000Pa, and the time is 50-60min.

3. A method of refining natural eucalyptus oil according to claim 1, characterized by: In the chromatographic purification column, the diameter-height ratio of the filler is 1:8-10; in the process of the cycle chromatography, the eluent is anhydrous ethanol.

4. A method of refining natural eucalyptus oil according to claim 1, characterized by: The alkenyl-modified filler comprises the following raw materials by mass: 9-10 parts of nano-porous silicon dioxide, 40-50 parts of 60% anhydrous ethanol solution, and 1-1.5 parts of 3-(isobutenyl) propyl trimethoxysilane; The carboxyl-modified filler comprises the following raw materials by mass: 4-6 parts of the alkenyl-modified filler, 40-50 parts of deionized water, 0.2-0.3 parts of mercaptoacetic acid, and 0.05-0.1 parts of azobisisobutyronitrile; The phthalimide-modified filler comprises the following raw materials by mass: 4-6 parts of the carboxyl-modified filler, 30-40 parts of anhydrous ether, 0.3-0.4 parts of 4-amino phthalimide, and 0.5-0.6 parts of an activator; The filler comprises the following raw materials by mass: 1.8-2 parts of tetrachlorophthalic anhydride, 18-20 parts of urea, 0.1-0.2 parts of ammonium molybdate, and 4-6 parts of the phthalimide-modified filler.

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