A method for simultaneously preparing linalool and borneol from camphor essential oil

Abstract

The invention discloses a method for simultaneously preparing linalool and borneol from camphor tree essential oil. The camphor tree essential oil obtained from camphor tree leaves by steam distillation is used as raw material. Molecular distillation technology is adopted. The vacuum degree of the molecular distiller is controlled to be less than 10 Torr, the refrigeration temperature is 3-8 ° C, the distillation temperature is 35-45 ° C, the scraper speed is 300-800 rpm, the essential oil injection flow rate is 1-2 drops / second, and a one-step preparation can obtain linalool and borneol products with a purity greater than 90%, respectively. The preparation method of the present invention has simple process, easy operation, short production cycle, is convenient for continuous large-scale process production, and has good product quality. The obtained essential oils are all colorless clear liquids.

Description

Technical Field

[0001] The invention belongs to the technical field of spice extraction, and in particular relates to a method for simultaneously preparing linalool and borneol from camphor tree essential oil. Background Art

[0002] Camphor essential oil is a key secondary metabolite of camphor trees. Its remarkable efficacy is evident in its use to relieve bronchitis, colds, coughs, fevers, insect bites, back pain, muscle aches, rheumatism, sprains, and bruises; it also alleviates psychological symptoms such as depression, frustration, low self-esteem, shyness, fatigue, and stress-related physical symptoms; and it is often used as an inhaler to stimulate heart, respiratory, and circulatory function, improve low blood pressure, and purify congested lungs for easier breathing. These active ingredients are derived from a single component or components of camphor essential oil, making systematic research on the theory and technology of camphor essential oil extraction and separation of camphor essential oil of great significance.

[0003] Camphor tree essential oil has a complex and diverse composition, often including dozens or even more compounds. Each compound has distinct physical and chemical properties, and the proportions and properties of some compounds may be affected to varying degrees by various factors during the extraction and separation process. Some essential oil products are unstable, volatile, and easily damaged. Therefore, mild conditions are often selected during the production process, and extraction and separation are performed at the lowest possible temperature and in a clean environment.

[0004] Currently, there are many methods for separating and preparing the main active ingredients of camphor tree essential oil (linalool, borneol, etc.), most of which use vacuum distillation and extractive distillation. There are also chemical methods for separation based on the differences in the physicochemical properties and functional group characteristics of different chemical components in camphor tree essential oil, and column chromatography separation based on the polarity differences of different chemical components in camphor tree essential oil.

[0005] When using vacuum distillation and extractive distillation to prepare essential oil components such as linalool in camphor tree essential oil, there are high requirements for equipment and site space, or organic solvents will be used in the preparation process, and the distillation effect is greatly affected by the different sources of camphor tree essential oil raw materials (different origins, different harvesting seasons, etc.), and the process control cost is high.

[0006] When chemical methods are used to separate the different chemical components in camphor tree essential oil based on the differences in physicochemical properties and functional group characteristics, such as separation based on differences in acidity and alkalinity, or separation based on functional group characteristics, methods such as pH gradient extraction and chemical structure modification are used. These methods are commonly used in the laboratory research stage and are difficult to apply in actual production.

[0007] Column chromatography separation methods, such as silica gel and alumina adsorption column chromatography and macroporous resin column chromatography, are used based on the polarity differences among different chemical components in camphor tree essential oil. These methods require the polarity differences among different components of camphor tree essential oil and are less effective for essential oil components with small polarity differences. In addition, organic solvents are required as elution reagents during the column chromatography separation process, which is costly and requires high safety requirements. It is also difficult to prepare several essential oil components at the same time.

[0008] All of the above methods are effective preparation methods, but they are basically only targeted at single essential oil components (such as linalool, citral, borneol, etc.). Most of them have the characteristics of complex process flows, long production cycles, high safety requirements, and high requirements for the raw materials of camphor essential oil. At present, there are few reports on process technologies that can simultaneously prepare several high-quality camphor essential oil components. Summary of the Invention

[0009] In order to overcome the technical problems in the prior art, the present invention provides a method for simultaneously preparing linalool and borneol from camphor essential oil. The method can simultaneously prepare linalool and borneol products in one step through a simple process. The prepared linalool and borneol are both colorless clear liquids with pure fragrance, and the content of both can reach more than 90%.

[0010] In order to solve the above technical problems, the technical solutions proposed by the present invention are as follows:

[0011] The present invention provides a method for simultaneously preparing linalool and borneol from camphor tree essential oil, comprising the following steps:

[0012] The camphor tree essential oil is separated by using a molecular distiller, wherein the camphor tree essential oil is separated by using a molecular distiller, wherein the vacuum degree is less than 10 Torr, the refrigeration temperature is 3-8°C, the distillation temperature is 35-45°C, the scraper speed is 300-800 rpm, and the essential oil injection flow rate is 1-2 drops / second to obtain an upper light oil and a medium light oil, wherein the upper light oil is linalool and the medium light oil is borneol.

[0013] In the present invention, different components are obtained by controlling the vacuum degree, refrigeration temperature, distillation temperature, scraper speed and injection speed of a molecular distiller, thereby achieving separation of different components in camphor tree essential oil. During molecular distillation, components with lower boiling points are more likely to rise to higher levels in a fractionating column, while components with higher boiling points tend to remain at lower levels. The upper light oil in the present invention is a component with a lower boiling point, the middle light oil is a component with a higher boiling point, and the heavy oil is a component with a higher boiling point in the mixture. By collecting the evaporated liquid at a certain level, separation of specific components in the mixture can be achieved.

[0014] In the present invention, if the vacuum exceeds 10 Torr or the refrigeration temperature is too high, the separation of the essential oil products is poor, resulting in small amounts of upper light oil and medium light oil. If the distillation temperature is too high, the distillation effect is poor, making it difficult to effectively separate linalool and borneol. If the distillation temperature is too low, the products cannot be effectively distilled, and the distillation efficiency is too low. If the scraper speed is too low, it is difficult to ensure the separation of the essential oil products, while if it is too fast, the long-term operation will cause significant equipment damage.

[0015] As an optional embodiment, in the preparation method provided by the present invention, the preparation method satisfies any one or more of the following items (1)-(5):

[0016] (1) The vacuum degree of the molecular distiller is 5 Torr;

[0017] (2) Refrigeration temperature is 5°C;

[0018] (3) Distillation temperature is 40°C;

[0019] (4) The scraper speed is 500 rpm;

[0020] (5) The essential oil injection flow rate is 1 drop / second.

[0021] As an optional embodiment, in the preparation method provided by the present invention, the purity of linalool in the upper light oil is greater than 90%, and the purity of borneol in the medium light oil is greater than 90%.

[0022] As an optional embodiment, in the preparation method provided by the present invention, the camphor tree essential oil used as the molecular distillation raw material is prepared by a steam distillation method.

[0023] As an optional embodiment, in the preparation method provided by the present invention, the camphor tree essential oil is steam distilled using fresh camphor tree leaves as raw materials.

[0024] In the present invention, fresh camphor leaves are used to more easily obtain essential oil, and the yield of the essential oil is guaranteed. However, the use of dried camphor leaves may affect the quality and yield of the essential oil obtained due to the loss of essential oil components during the drying process.

[0025] As an optional embodiment, in the preparation method provided by the present invention, the content of linalool in the camphor tree essential oil is greater than 15%, the content of borneol in the camphor tree essential oil is greater than 10%, and the sum of the contents of linalool and borneol is greater than 30%.

[0026] As an optional embodiment, in the preparation method provided by the present invention, the purity of the linalool and borneol is detected by gas chromatograph, the chromatographic column is a Wonda Cap 5 non-polar capillary column with a specification of 30m×0.25mm×0.25μm, the carrier gas is N2, the carrier gas flow rate is 29.3mL / min, the injection volume is 1.0μL / time, split injection, injection time is 1min, and the detector temperature is 280°C

[0027] As an optional embodiment, in the preparation method provided by the present invention, the temperature rising program of the gas chromatograph is as follows: first maintain at 70°C for 2 minutes, then reach 180°C at 5°C / min, and finally reach 250°C at 10°C / min. The program runs for a total of 31 minutes.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention adopts a molecular distillation method, and provides a preparation process for simultaneously separating linalool and borneol products from camphor tree essential oil by controlling the vacuum degree, distillation temperature, refrigerant temperature, sample feed flow rate, and scraper speed. The process is simple, easy to operate, has a short production cycle, is convenient for cost control, and is suitable for continuous large-scale production.

[0030] (2) The linalool and borneol products obtained by the present invention are of good quality and pure fragrance, are both colorless clear liquids, and have a content of more than 90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 The gas chromatograph detection spectrum of the camphor tree essential oil in Example 1 of the present invention;

[0033] Figure 2 The gas chromatograph detection spectrum of linalool obtained in Example 1 of the present invention;

[0034] Figure 3 The gas chromatograph detection spectrum of borneol obtained in Example 1 of the present invention is shown. DETAILED DESCRIPTION

[0035] To facilitate understanding of the present invention, the present invention will be described in more comprehensive and detailed form below in conjunction with the accompanying drawings and preferred embodiments. However, the protection scope of the present invention is not limited to the following specific embodiments.

[0036] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0037] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0038] Example 1

[0039] 100 mL of camphor essential oil raw material was prepared by steam distillation using fresh camphor leaves as raw material, wherein the linalool content was 17.35% and the borneol content was 14.75%. The oil was separated using a US pope brand molecular distiller (33A3BEPM): under the conditions of a vacuum degree of 5 Torr, a refrigeration temperature of 5°C, a distillation temperature of 40°C, and a scraper speed of about 500 rpm, the essential oil injection flow rate was controlled at 1 to 2 drops / second, and about 70 mL of heavy oil (brown-yellow clear liquid, slightly viscous), about 15 mL of medium light oil (clear and colorless), and about 12 mL of upper light oil (clear and colorless).

[0040] The heavy oil was subjected to secondary molecular distillation. Other conditions remained unchanged, except that the distillation temperature was increased to 50°C, to obtain about 15 mL of secondary heavy oil (dark brown oil, obviously viscous), and about 50 mL of upper light oil and medium light oil (clear and colorless).

[0041] Thin layer chromatography (TLC) detection showed that the upper light oil and medium light oil obtained from the first distillation were the target components linalool and borneol, respectively, and their purity was very high; the upper light oil and medium light oil from the second distillation contained very small amounts of the target components linalool and borneol, and it was obvious that the effect of the first distillation was better than that of the second distillation.

[0042] The camphor tree essential oil, the upper light oil and the medium light oil obtained by single distillation are respectively tested for the purity of linalool and borneol by gas chromatography (GC), and the detection method comprises the following steps:

[0043] (1) Preparation of sample solution:

[0044] Take camphor essential oil, separated and purified linalool and borneol products, accurately pipette 0.1 mL of each into a 10 mL stoppered test tube, then add analytical grade acetone to 4 mL respectively. After mixing and dissolving, take each sample solution and filter it through a 0.45 μm filter membrane to obtain the filtrate for testing.

[0045] (2) Preparation of linalool and borneol standard solution:

[0046] Prepare the sample solutions as described above. Accurately pipette 0.1 mL of linalool and 5 mg of borneol into a 5 mL volumetric flask. Add analytical grade acetone to 5 mL of each solution. Mix thoroughly to dissolve. Filter each sample through a 0.45 μm filter and set aside. (Linalool, 98% purity, L106905-25 mL, Shanghai Aladdin Reagent; borneol, 98% purity, B119291-200 mg, Shanghai Aladdin Reagent)

[0047] (3) Gas chromatography (GC) detection conditions

[0048] The gas chromatograph was a Shimadzu GC (GC-2010pro), and the chromatographic column was a Wonda Cap 5 non-polar capillary column (30 m × 0.25 mm × 0.25 μm). The carrier gas was N2 at a flow rate of 29.3 mL / min, with an injection volume of 1.0 μL / time, split injection, and an injection time of 1 min. The detector temperature was 280°C.

[0049] GC temperature program: first maintain at 70°C for 2 minutes, then increase the temperature to 180°C at 5°C / min, and finally increase the temperature to 250°C at 10°C / min. The program runs for a total of 31 minutes.

[0050] (4) Calculation method of linalool and borneol content in camphor essential oil

[0051] After the sample solution was detected by gas chromatography, the linalool and borneol contents of the sample solution were obtained using the area normalization method.

[0052] The results are as follows Figure 1-3 As shown, Figure 1 is the GC spectrum of camphor tree essential oil raw material, in which t R =10.320 peak is linalool, t R =11.756 peak is borneol; Figure 2 This is the GC spectrum of the upper light oil obtained by single distillation. R =10.492 peak is linalool, and the obtained upper light oil contains linalool with a purity of 95.26%; Figure 3 This is the GC spectrum of the medium-light oil obtained by single distillation. R =11.728 peak is borneol, and the purity of borneol in the obtained medium-light oil is 92.18%.

[0053] Example 2

[0054] 100 mL of camphor essential oil raw material prepared by steam distillation using fresh camphor leaves as raw material, wherein the linalool content is 17.75% and the borneol content is 15.05%, is separated using an American pope brand molecular distiller (33A3BEPM): under the conditions of a vacuum degree of 8 Torr, a refrigeration temperature of 8°C, a distillation temperature of 45°C, and a scraper speed of about 400 rpm, the essential oil injection flow rate is controlled at 1 to 2 drops / second, and about 68 mL of heavy oil (brown-yellow clear liquid, slightly viscous), about 18 mL of medium light oil (clear and colorless), and about 10 mL of upper light oil (clear and colorless) are obtained.

[0055] Thin layer chromatography (TLC) analysis showed that the upper light oil and medium light oil obtained by single distillation contained the target components linalool and borneol, respectively, with high purity. The purity of linalool and borneol was further tested by gas chromatography (GC), and the purities obtained were 93.12% and 90.33%, respectively.

[0056] Example 3

[0057] 100 mL of camphor essential oil raw material was prepared by steam distillation using fresh camphor leaves as raw material, wherein the linalool content was 19.36% and the borneol content was 13.45%. The oil was separated using a US pope brand molecular distiller (33A3BEPM): under the conditions of a vacuum degree of 8 Torr, a refrigeration temperature of 8°C, a distillation temperature of 35°C, and a scraper speed of about 800 rpm, the essential oil injection flow rate was controlled at 1 to 2 drops / second, and about 75 mL of heavy oil (brown-yellow clear liquid, slightly viscous), about 13 mL of medium light oil (clear and colorless), and about 9 mL of upper light oil (clear and colorless).

[0058] Thin layer chromatography (TLC) analysis showed that the upper light oil and medium light oil obtained by single distillation contained the target components linalool and borneol, respectively, with high purity. The purity of linalool and borneol was further detected by gas chromatography (GC) using the same detection method as in Example 1, and the obtained purities were 94.45% and 93.68%, respectively.

[0059] Example 4

[0060] 100 mL of camphor essential oil raw material was prepared by steam distillation using fresh camphor leaves as raw material, wherein the linalool content was 19.06% and the borneol content was 14.37%. The oil was separated using a US pope brand molecular distiller (33A3BEPM): under the conditions of a vacuum degree of 8 Torr, a refrigeration temperature of 3°C, a distillation temperature of 42°C, and a scraper speed of about 800 rpm, the essential oil injection flow rate was controlled at 1 to 2 drops / second, and about 70 mL of heavy oil (brown-yellow clear liquid, slightly viscous), about 16 mL of medium light oil (clear and colorless), and about 10 mL of upper light oil (clear and colorless).

[0061] Thin layer chromatography (TLC) analysis showed that the upper light oil and medium light oil obtained by single distillation contained the target components linalool and borneol, respectively, with high purity. The purity of linalool and borneol was further detected by gas chromatography (GC) using the same detection method as in Example 1, and the obtained purities were 92.28% and 91.12%, respectively.

[0062] Example 5

[0063] Further amplification verification test was carried out, 500 mL of the camphor tree essential oil raw material used in Example 1 was taken, and separation was carried out using an American pope brand molecular distiller (33A3BEPM): the vacuum degree was 5 Torr, the refrigeration temperature was 5 ° C, the distillation temperature was 40 ° C, and the scraper speed was about 500 rpm. The essential oil injection flow rate was controlled at 1 to 2 drops / second to obtain about 330 mL of heavy oil (light brown clear liquid, slightly viscous), about 90 mL of upper light oil (clear and colorless), and about 80 mL of medium light oil (clear and colorless).

[0064] The heavy oil was subjected to secondary molecular distillation. Other conditions remained unchanged, and only the distillation temperature was increased to 80°C to obtain about 30 mL of secondary heavy oil (dark black oily substance, very viscous), about 100 mL of upper light oil (basically clear and colorless), and about 200 mL of medium light oil (slightly yellow clear liquid).

[0065] TLC analysis revealed that the components contained in the upper light oil and the medium light oil obtained by the first distillation were of high purity, and the effect of the first distillation was significantly better than that of the second distillation. The upper light oil and the medium light oil obtained by the first distillation were respectively detected by gas chromatograph (GC) using the same detection method as in Example 1. The upper light oil had a linalool purity of 93.16%, and the medium light oil had a borneol purity of 92.05%.

[0066] Comparative Example 1

[0067] 100 mL of camphor essential oil raw material prepared by steam distillation using fresh camphor leaves as raw material, wherein the linalool content is 17.35% and the borneol content is 14.75%, is separated using an American pope brand molecular distiller (33A3BEPM): under the conditions of a vacuum degree of 5 Torr, a refrigeration temperature of 5°C, a distillation temperature of 50°C, and a scraper speed of about 500 rpm, the essential oil injection flow rate is controlled at 1 to 2 drops / second, and about 20 mL of heavy oil (brown oily, relatively viscous), about 40 mL of medium light oil (clear and colorless), and about 35 mL of upper light oil (clear and colorless) are obtained.

[0068] Thin layer chromatography (TLC) analysis showed that the upper light oil and medium light oil obtained were mainly composed of linalool and borneol, respectively, but also contained other obvious components.

[0069] The upper light oil and the medium light oil were further tested for the purity of linalool and borneol by gas chromatography (GC), respectively. The detection method was the same as in Example 1, and the upper light oil had a linalool purity of 43.57%, and the medium light oil had a borneol purity of 35.87%.

[0070] In summary, it can be concluded that when the distillation temperature is 50°C, the separation effect is obviously not as good as that at 40°C.

[0071] Comparative Example 2

[0072] Get used camphor tree essential oil raw material 100mL among the embodiment 1, wherein containing linalool content is 17.35%, and the content of borneol is 14.75%, adopt U.S. pope board molecular distiller (33A3BEPM) to separate: be 20Torr in vacuum tightness, refrigeration temperature is 5 ℃, and distillation temperature is 40 ℃, and the scraper rotating speed is about under the condition of 500rpm, the essential oil inlet flow rate is controlled at 1~2 drop / second, obtains the about 80mL of heavy oil (light brown oily matter, more viscous), the about 10mL of middle light oil (clear and colorless) and the about 8mL of upper light oil (clear and colorless).

[0073] Thin layer chromatography (TLC) analysis revealed that the upper light oil and medium light oil were primarily composed of linalool and borneol, respectively, but also contained significant amounts of other components, resulting in poor purity. The upper light oil and medium light oil were further analyzed for linalool and borneol purity using the same method as in Example 1. The upper light oil had a linalool purity of 76.36%, while the medium light oil had a borneol purity of 70.38%.

[0074] In summary, it can be concluded that a significant decrease in vacuum degree has a significant impact on both product purity and product quantity.

[0075] Comparative Example 3

[0076] Get used camphor tree essential oil raw material 100mL among the embodiment 1, wherein containing linalool content is 17.35%, and the content of borneol is 14.75%, adopt U.S. pope board molecular distiller (33A3BEPM) to separate: be 8Torr in vacuum tightness, refrigeration temperature is 8 ℃, and distillation temperature is 30 ℃, and the scraper rotating speed is about under the condition of 1000rpm, the essential oil inlet flow rate is controlled at 1~2 drops / second, obtains heavy oil about 85mL (brown clear liquid, slightly viscous), middle light oil about 10mL (clear and colorless) and upper light oil about 2mL (clear and colorless).

[0077] Thin layer chromatography (TLC) analysis showed that the upper light oil and medium light oil obtained were mainly composed of linalool and borneol, respectively. The purity of linalool and borneol was further detected by gas chromatography (GC) using the same detection method as in Example 1, and the obtained purities were 88.31% and 89.18%, respectively.

[0078] In summary, it can be concluded that too low a distillation temperature will also have a significant impact on product purity and product quantity.

[0079] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the scope of protection of the present invention.

Claims

1. A method for simultaneously preparing linalool and borneol from camphor essential oil, characterized in that, The following steps are involved: Camphor essential oil prepared by steam distillation using fresh camphor leaves as raw material is separated using a molecular distiller, wherein the vacuum degree is less than 10 Torr, the refrigeration temperature is 3-8°C, the distillation temperature is 35-45°C, the scraper speed is 300-800 rpm, and the essential oil injection flow rate is 1-2 drops / second to obtain an upper light oil and a medium light oil, wherein the upper light oil is linalool and the medium light oil is borneol; The content of linalool in the camphor essential oil is greater than 15%, the content of borneol in the camphor essential oil is greater than 10%, and the sum of the contents of linalool and borneol is greater than 30%; The purity of linalool in the upper light oil is greater than 90%, and the purity of borneol in the medium light oil is greater than 90%.

2. The method for simultaneously preparing linalool and borneol from camphor essential oil according to claim 1, wherein The preparation method satisfies any one or more of the following (1) to (5): (1) The vacuum degree of the molecular distiller is 5 Torr; (2) Refrigeration temperature is 5°C; (3) Distillation temperature is 40°C; (4) The scraper speed is 500 rpm; (5) The essential oil injection flow rate is 1 drop / second.

3. The method for simultaneously preparing linalool and borneol from camphor essential oil according to claim 1, wherein The purity of the linalool and borneol was detected by gas chromatography, the chromatographic column was a Wonda Cap 5 non-polar capillary column with a specification of 30 m×0.25 mm×0.25 μm, the carrier gas was N2, the carrier gas flow rate was 29.3 mL / min, the injection volume was 1.0 μL / time, split injection was used, the injection time was 1 min, and the detector temperature was 280°C.

4. The method for simultaneously preparing linalool and borneol from camphor essential oil according to claim 3, wherein The temperature rise program of the gas chromatograph was as follows: first, maintain at 70°C for 2 min, then increase the temperature to 180°C at 5°C / min, and finally increase the temperature to 250°C at 10°C / min. The program ran for a total of 31 min.

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