Method for removing heavy metals in borneol
By mixing, filtering, and crystallizing crude borneol with propolis and activated carbon, the problem of heavy metal contamination in borneol was solved, improving the safety and efficacy of borneol and making it suitable for industrial production.
Patent Information
- Application Number
- CN202510932125.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-07
- Publication Date
- 2025-10-31
Smart Images
Figure BDA0005486665010000051 
Figure BDA0005486665010000052 
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Abstract
Description
Technical Field
[0001] This invention relates to the field of pharmaceuticals and chemicals, and specifically to a method for removing heavy metals from borneol. Background Technology
[0002] Borneol, also known as camphor, has the chemical name 2-camphor and the molecular formula C60. 10 H 18 Borneol (CAS Registry Number: 507-70-0) is commonly prepared using synthetic methods in current technologies. However, factors such as raw material sources, preparation processes, and equipment often lead to excessive levels of heavy metals like arsenic (As), lead (Pb), mercury (Hg), cadmium (Cd), and copper (Cu) in the prepared borneol. This heavy metal contamination seriously affects the safety and efficacy of borneol. The accumulation of heavy metals can cause neurological damage and kidney dysfunction, hindering the promotion and use of borneol and posing a threat to patient health. Therefore, strengthening the control of heavy metals in traditional Chinese medicine is crucial. However, current technologies lack an effective method for removing heavy metals from borneol, thus limiting its application value.
[0003] Therefore, there is a need in this field to develop a method that can effectively reduce the heavy metal content in borneol, thereby improving the application value of borneol. Summary of the Invention
[0004] The purpose of this invention is to provide a method for reducing the heavy metal content in borneol, thereby improving the application value of borneol.
[0005] In a first aspect, the present invention provides a method for reducing the heavy metal content in borneol, the method comprising the steps of:
[0006] (1) Mix crude borneol with an organic solvent to obtain a crude borneol solution;
[0007] (2) Add propolis and activated carbon to the crude borneol solution obtained in step (1), stir, filter, concentrate the filtrate under reduced pressure, crystallize the concentrated solution, filter, and dry the solid to obtain pure borneol, thereby reducing the heavy metal content in borneol.
[0008] Preferably, the crude borneol contains heavy metals.
[0009] Preferably, the heavy metal includes one or more selected from the group consisting of arsenic, lead, mercury, cadmium, copper, or combinations thereof.
[0010] Preferably, the heavy metal includes one or more of arsenic, lead, mercury, cadmium, and copper.
[0011] Preferably, the heavy metals include arsenic, lead, mercury, cadmium, and copper.
[0012] Preferably, in step (1), the organic solvent includes n-heptane.
[0013] Preferably, in step (1), the mass (kg) of the crude borneol to the volume (L) of the n-heptane (kg:L) ratio (kg:L) is 1:(10-30), more preferably 1:(15-25), even more preferably 1:(16-20), even more preferably 1:(17-19), and most preferably 1:18.
[0014] Preferably, in step (1), the mixing includes stirring, mixing, and dissolving.
[0015] Preferably, in step (1), the mixing temperature is 50-85°C, more preferably 50-80°C, even more preferably 55-75°C, even more preferably 60-70°C, even more preferably 63-67°C, and most preferably 65°C.
[0016] Preferably, in step (2), the propolis comprises propolis that has been pre-frozen and then pulverized.
[0017] Preferably, in step (2), the particle size of the propolis is 20-80 mesh, more preferably 30-70 mesh, even more preferably 35-65 mesh, even more preferably 40-60 mesh, even more preferably 45-55 mesh, and most preferably 50 mesh.
[0018] Preferably, in step (2), the activated carbon includes activated carbon for injection.
[0019] Preferably, in step (2), the mass ratio of propolis to activated carbon is 1:(1-5), more preferably 1:(1.5-4.0), more preferably 1:(2-3.5), more preferably 1:(2.2-3.0), more preferably 1:(2.4-2.8), and most preferably 1:2.6.
[0020] Preferably, the mass ratio of crude borneol in step (1) to propolis in step (2) is 1:(0.03-0.3), more preferably 1:(0.05-0.2), even more preferably 1:(0.05-0.15), even more preferably 1:(0.08-0.12), even more preferably 1:(0.09-0.11), and most preferably 1:0.095.
[0021] Preferably, the mass ratio of crude borneol in step (1) to activated carbon in step (2) is 1:(0.1-0.5), more preferably 1:(0.1-0.4), even more preferably 1:(0.15-0.35), even more preferably 1:(0.2-0.3), even more preferably 1:(0.23-0.27), and most preferably 1:0.25.
[0022] Preferably, in step (2), the mass ratio of propolis to activated carbon is 1:(0.5-8), more preferably 1:(0.8-5), even more preferably 1:(1-4), even more preferably 1:(1.5-3.5), even more preferably 1:(1.6-3.0), and most preferably 1:2-2.6.
[0023] Preferably, the mass ratio of crude borneol in step (1) to propolis in step (2) is 1:(0.003-0.5), more preferably 1:(0.005-0.3), even more preferably 1:(0.008-0.2), even more preferably 1:(0.01-0.15), even more preferably 1:(0.02-0.12), and most preferably 1:0.03-0.095.
[0024] Preferably, the mass ratio of crude borneol in step (1) to activated carbon in step (2) is 1:(0.01-0.5), more preferably 1:(0.02-0.4), even more preferably 1:(0.03-0.35), even more preferably 1:(0.04-0.3), even more preferably 1:(0.05-0.27), and most preferably 1:0.06-0.25.
[0025] Preferably, in step (2), the stirring temperature is 50-85℃, more preferably 50-80℃, even more preferably 55-75℃, even more preferably 60-70℃, even more preferably 63-67℃, and most preferably 65℃.
[0026] Preferably, in step (2), the stirring time is 0.5-6h, more preferably 1-5h, more preferably 2-4h, more preferably 2.5-3.5h, more preferably 2.8-3.2h, and most preferably 3h.
[0027] Preferably, in step (2), the filtration after stirring includes filtration with a filter having a pore size of 0.5-15μm, more preferably 1-10μm, more preferably 1-8μm, more preferably 3-7μm, more preferably 4-6μm, and most preferably 5μm.
[0028] Preferably, in step (2), after crystallization, the temperature of the solution is lowered to 6-25°C, more preferably 8-20°C, even more preferably 8-15°C, even more preferably 10-14°C, and most preferably 12°C, before filtration.
[0029] Preferably, the volume ratio of the concentrated liquid after vacuum concentration in step (2) to the n-heptane in step (1) is 1:(3-10), more preferably 1:(4-8), more preferably 1:(5-7), more preferably 1:(5.5-6.5), more preferably 1:(5.8-6.2), and most preferably 1:6.
[0030] Preferably, in step (2), the crystallization temperature is 3-10℃, more preferably 4-8℃, more preferably 5-7℃, more preferably 5.5-6.5℃, more preferably 5.8-6.2℃, and most preferably 6℃.
[0031] Preferably, in step (2), the crystallization time is 5-15 days, more preferably 5-12 days, even more preferably 6-12 days, even more preferably 7-11 days, even more preferably 8-10 days, and most preferably 9 days.
[0032] Preferably, in step (2), the crystallization includes standing at 3-10°C (preferably 4-8°C, more preferably 5-7°C, more preferably 5.5-6.5°C, more preferably 5.8-6.2°C, most preferably 6°C) for 5-15 days (preferably 5-12 days, more preferably 6-12 days, more preferably 7-11 days, more preferably 8-10 days, most preferably 9 days).
[0033] Preferably, in step (2), the pure borneol product includes one or more of the following characteristics:
[0034] (i) The arsenic content does not exceed 0.1 mg / kg;
[0035] (ii) The lead content does not exceed 0.5 mg / kg;
[0036] (iii) The mercury content does not exceed 0.1 mg / kg;
[0037] (iv) The cadmium content does not exceed 0.2 mg / kg; and / or
[0038] (v) The copper content does not exceed 0.2 mg / kg.
[0039] Preferably, the method for reducing the heavy metal content in borneol includes a method for removing heavy metals from borneol.
[0040] Preferably, the method for reducing the heavy metal content in borneol includes ensuring that the content of arsenic in borneol does not exceed 0.1 mg / kg, the content of lead does not exceed 0.5 mg / kg, the content of mercury does not exceed 0.1 mg / kg, the content of cadmium does not exceed 0.2 mg / kg, and / or the content of copper does not exceed 0.2 mg / kg.
[0041] Preferably, the method includes:
[0042] (1) Weigh 1 kg of crude borneol and 18 L of n-heptane and add them to the reaction vessel. Stir and dissolve at 65 °C to obtain a crude borneol solution.
[0043] (2) Add 95g of pre-frozen and pulverized propolis to the crude borneol solution obtained in step (1) and 248g of activated carbon (for injection). Continue stirring at 65°C for 3 hours, then cool to 12°C and filter through a 5μm filter. Concentrate the filtrate under reduced pressure to 3L, let it stand at 6°C for 9 days to crystallize, filter, and dry the solid to obtain pure borneol, thereby reducing the heavy metal content in borneol.
[0044] Preferably, the crude borneol is prepared by the following method:
[0045] (a) After saponification of Borneol Oxalate and potassium hydroxide aqueous solution, the mixture is allowed to stand and separate into layers. The upper layer is a layer containing coarse borneol, and the lower layer containing potassium oxalate wastewater is discharged.
[0046] (b) The layer containing coarse borneol is centrifuged to obtain crude borneol.
[0047] Preferably, in step (a), the potassium hydroxide aqueous solution contains 20-60 wt% potassium hydroxide, more preferably 30-50 wt%, even more preferably 35-45 wt%, even more preferably 38-42 wt%, and most preferably 40 wt%.
[0048] Preferably, in step (a), the mass ratio of bornyl oxalate to the aqueous potassium hydroxide solution is (0.3-3.0):1, more preferably (0.5-2.0):1, even more preferably (0.8-1.6):1, even more preferably (1.0-1.4):1, and most preferably 1.2:1.
[0049] Preferably, in step (a), the reaction pressure is 0.01-0.2 MPa, more preferably 0.01-0.15 MPa, even more preferably 0.01-0.1 MPa, even more preferably 0.03-0.07 MPa, and most preferably 0.05 MPa.
[0050] Preferably, in step (a), the reaction temperature is 60-100°C, more preferably 70-90°C, even more preferably 75-85°C, even more preferably 78-82°C, and most preferably 80°C.
[0051] Preferably, in step (b), the product is centrifuged and then washed with water to obtain crude borneol.
[0052] Preferably, in step (a), after centrifugation, the product is washed with water at 80-100℃ (preferably 85-100℃, more preferably 90-100℃, and most preferably 95℃) to obtain crude borneol.
[0053] Preferably, the crude borneol is prepared by the following method:
[0054] (A) Add 700 kg of bornyl oxalate and 600 kg of 40 wt% potassium hydroxide aqueous solution to a reaction vessel and carry out a saponification reaction for 60 min; the pressure of the reaction vessel is 0.05 MPa and the reaction temperature is 80 °C.
[0055] (B) After the reaction is completed, the mixture is allowed to stand and separate into layers. The upper layer is a layer containing coarse camphor, and the lower layer containing potassium oxalate wastewater is discharged.
[0056] (C) The coarse borneol layer is centrifuged and washed with hot water at 95°C to obtain crude borneol.
[0057] In a second aspect, the present invention provides a method for preparing pure borneol, the method comprising the steps of:
[0058] (1) Mix crude borneol with an organic solvent to obtain a crude borneol solution;
[0059] (2) Add propolis and activated carbon to the crude borneol solution obtained in step (1), stir, filter, concentrate the filtrate under reduced pressure, crystallize the concentrated solution, filter, and dry the solid to obtain pure borneol.
[0060] Preferably, step (1) is as described in the first aspect of the present invention above.
[0061] Preferably, step (2) is as described in the first aspect of the present invention above.
[0062] In a third aspect, the present invention provides a pure borneol product, which is prepared by the method described in the first aspect of the present invention.
[0063] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Detailed Implementation
[0064] This invention provides a method for effectively reducing the heavy metal content in borneol. The method can effectively reduce the content of heavy metals such as arsenic, lead, mercury, cadmium and copper in borneol, thereby improving the application value of borneol.
[0065] the term
[0066] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0067] As used herein, the terms “comprising,” “including,” and “containing” are used interchangeably and include not only open-ended definitions but also semi-closed and closed definitions. In other words, the terms include “consisting of” and “substantially consisting of”.
[0068] As used in this article, the English word for "propolis" is Propolis.
[0069] method
[0070] This invention provides a method for reducing the heavy metal content in borneol, the method comprising the following steps:
[0071] (1) Mix crude borneol with an organic solvent to obtain a crude borneol solution;
[0072] (2) Add propolis and activated carbon to the crude borneol solution obtained in step (1), stir, filter, concentrate the filtrate under reduced pressure, crystallize the concentrated solution, filter, and dry the solid to obtain pure borneol, thereby reducing the heavy metal content in borneol.
[0073] Specifically, the method for reducing the heavy metal content in borneol described in this invention is as described in the first aspect of this invention above.
[0074] In a preferred embodiment of the present invention, the method for reducing the heavy metal content in borneol includes ensuring that the content of arsenic in borneol does not exceed 0.1 mg / kg, the content of lead does not exceed 0.5 mg / kg, the content of mercury does not exceed 0.1 mg / kg, the content of cadmium does not exceed 0.2 mg / kg, and / or the content of copper does not exceed 0.2 mg / kg.
[0075] The main technical effects of this invention include:
[0076] This invention provides a method for effectively reducing the heavy metal content in borneol. The method effectively reduces the content of heavy metals such as arsenic, lead, mercury, cadmium, and copper in borneol, ensuring that the purified borneol fully meets the heavy metal limits for traditional Chinese medicine decoction pieces as stipulated in the Chinese Pharmacopoeia. This effectively controls heavy metal content in borneol and improves its application value. Furthermore, the method for reducing heavy metal content in borneol described in this invention is simple to operate, low in cost, and has a significant effect on reducing heavy metal content, making it suitable for large-scale industrial production.
[0077] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer.
[0078] Examples and Comparative Examples
[0079] The crude borneol in Examples 1-2 and Comparative Examples 1-5 was prepared by the following method:
[0080] (1) Add 700 kg of borneol oxalate and 600 kg of 40 wt% potassium hydroxide aqueous solution to the reaction vessel and carry out the saponification reaction for 60 min; the pressure of the reaction vessel is 0.05 MPa and the reaction temperature is 80 ℃.
[0081] (2) After the reaction is completed, the mixture is allowed to stand and separate into layers. The upper layer is a layer containing coarse camphor, and the lower layer containing potassium oxalate wastewater is discharged.
[0082] (3) The coarse borneol layer is centrifuged and washed with hot water at 95°C to obtain crude borneol.
[0083] Example 1
[0084] This embodiment 1 provides a method for removing heavy metals from camphor, the specific method is as follows:
[0085] (1) Weigh 1 kg of crude borneol and 18 L of n-heptane and add them to the reaction vessel. Stir and dissolve at 65 °C to obtain a crude borneol solution.
[0086] (2) Add 95g of pre-frozen and pulverized propolis to the crude borneol solution obtained in step (1) and 248g of activated carbon (for injection). Continue stirring at 65°C for 3 hours, then cool to 12°C and filter through a 5μm filter. Concentrate the filtrate under reduced pressure to 3L and let it stand at 6°C for 9 days to crystallize. Filter the solid and dry it to obtain pure borneol.
[0087] The method for detecting heavy metal residues in pure borneol is as follows:
[0088] Method for detecting heavy metal residues: Follow Appendix 2321, "Determination of Lead, Cadmium, Arsenic, Mercury, and Copper," of the 2025 edition of the Chinese Pharmacopoeia, Part IV. The limits for heavy metals in borneol are set as follows: arsenic not exceeding 0.1 mg / kg, lead not exceeding 0.5 mg / kg, mercury not exceeding 0.1 mg / kg, cadmium not exceeding 0.2 mg / kg, and copper not exceeding 0.2 mg / kg.
[0089] The heavy metal residues of the pure borneol prepared in Example 1 are shown in Table 1 below.
[0090] Table 1. Heavy metal residues in pure borneol
[0091]
[0092] As can be seen from Table 1, the method of Example 1 can effectively remove heavy metals from camphor.
[0093] Example 2
[0094] This embodiment 2 provides a method for removing heavy metals from camphor, the specific method is as follows:
[0095] (1) Weigh 1 kg of crude borneol and 18 L of n-heptane and add them to the reaction vessel. Stir and dissolve at 65 °C to obtain a crude borneol solution.
[0096] (2) Add 30g of pre-frozen and pulverized propolis to the crude borneol solution obtained in step (1) and 60g of activated carbon (for injection). Continue stirring at 65°C for 3 hours, then cool to 12°C and filter through a 5μm filter. Concentrate the filtrate under reduced pressure to 3L and let it stand at 6°C for 9 days to crystallize. Filter the solid and dry it to obtain pure borneol.
[0097] The method for detecting heavy metal residues in pure borneol is as follows:
[0098] Method for detecting heavy metal residues: Follow Appendix 2321, "Determination of Lead, Cadmium, Arsenic, Mercury, and Copper," of the 2025 edition of the Chinese Pharmacopoeia, Part IV. The limits for heavy metals in borneol are set as follows: arsenic not exceeding 0.1 mg / kg, lead not exceeding 0.5 mg / kg, mercury not exceeding 0.1 mg / kg, cadmium not exceeding 0.2 mg / kg, and copper not exceeding 0.2 mg / kg.
[0099] The heavy metal residue of the pure borneol prepared in Example 2 is shown in Table 2 below.
[0100] Table 2 Heavy metal residues in pure borneol
[0101]
[0102] As can be seen from Table 2, the method of this embodiment 2 can effectively remove heavy metals from camphor.
[0103] Comparative Example 1
[0104] Comparative Example 1 provides a method for removing heavy metals from camphor, which is the same as in Example 1, except that in step (1), n-heptane is replaced by ethanol, acetone or chloroform respectively.
[0105] The borneol prepared by the method of Comparative Example 1 is in amorphous granular or powder form, not in the same flaky crystal form as in Example 1. Its properties do not meet the requirements of the 2025 edition of the Chinese Pharmacopoeia for borneol (synthetic borneol), natural borneol, and artemisia argyi—"This product is a flaky crystal." Therefore, the borneol prepared by the method of Comparative Example 1 is a substandard product.
[0106] Comparative Example 2
[0107] Comparative Example 2 provides a method for removing heavy metals from camphor, which is the same as in Example 1, except that:
[0108] (2) Add 95g of pre-frozen, crushed and unsieved propolis and 248g of 65-mesh activated carbon to the crude borneol solution obtained in step (1). Continue stirring at 65°C for 3 hours, then cool to 12°C and filter through a 5μm filter. Concentrate the filtrate under reduced pressure to 3L and let it stand at 6°C for 9 days to crystallize. Filter the solid and dry it to obtain pure borneol.
[0109] The heavy metal residues of the pure borneol prepared in Comparative Example 2 are shown in Table 3 below.
[0110] Table 3 Heavy metal residues in pure borneol
[0111]
[0112] As can be seen from Table 3, the method in Comparative Example 2 cannot effectively remove heavy metals from borneol.
[0113] Comparative Example 3
[0114] Comparative Example 3 provides a method for removing heavy metals from camphor, which is the same as in Example 1, except that:
[0115] (2) Add 95g of pre-frozen and pulverized propolis to the crude borneol solution obtained in step (1), stir at 65°C for 3 hours, cool to 12°C, filter through a 5μm filter, concentrate the filtrate under reduced pressure to 3L, let it stand at 6°C for 9 days to crystallize, filter, and dry the solid to obtain pure borneol.
[0116] The heavy metal residues of the pure borneol prepared in Comparative Example 3 are shown in Table 4 below.
[0117] Table 4 Heavy metal residues in pure borneol
[0118]
[0119] As can be seen from Table 4, the method in Comparative Example 3 cannot effectively remove heavy metals from borneol.
[0120] Comparative Example 4
[0121] Comparative Example 4 provides a method for removing heavy metals from camphor, which is the same as in Example 1, except that:
[0122] (2) Add 248g of activated carbon (for injection) to the crude borneol solution obtained in step (1), continue stirring at 65°C for 3 hours, cool down to 12°C, filter through a 5μm filter, concentrate the filtrate under reduced pressure to 3L, let it stand at 6°C for 9 days to crystallize, filter, and dry the solid to obtain pure borneol.
[0123] The heavy metal residues of the pure borneol prepared in Comparative Example 4 are shown in Table 5 below.
[0124] Table 5 Heavy metal residues in pure borneol
[0125]
[0126] As can be seen from Table 5, the method in Comparative Example 4 cannot effectively remove heavy metals from borneol.
[0127] Comparative Example 5
[0128] Comparative Example 5 provides a method for removing heavy metals from camphor, which is the same as in Example 1, except that:
[0129] (2) Cool the crude borneol solution obtained in step (1) to 12°C, filter it through a 5μm filter, concentrate the filtrate to 3L under reduced pressure, let it stand at 6°C for 9 days to crystallize, filter it, and dry the solid to obtain pure borneol.
[0130] The heavy metal residues of the pure borneol prepared in Comparative Example 5 are shown in Table 6 below.
[0131] Table 6 Heavy metal residues in pure borneol
[0132]
[0133] As can be seen from Table 6, the method in Comparative Example 5 is not effective in removing heavy metals from borneol.
[0134] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.
Claims
1. A method for reducing the heavy metal content in borneol, characterized in that, The method includes the following steps: (1) Mix crude borneol with an organic solvent to obtain a crude borneol solution; (2) Add propolis and activated carbon to the crude borneol solution obtained in step (1), stir, filter, concentrate the filtrate under reduced pressure, crystallize the concentrated solution, filter, and dry the solid to obtain pure borneol, thereby reducing the heavy metal content in borneol.
2. The method as described in claim 1, characterized in that, The heavy metals include one or more of arsenic, lead, mercury, cadmium, and copper.
3. The method as described in claim 1, characterized in that, In step (1), the organic solvent includes n-heptane.
4. The method as described in claim 1, characterized in that, The propolis comprises pre-frozen and then pulverized propolis; and In step (2), the particle size of the propolis is 20-80 mesh, preferably 30-70 mesh, more preferably 35-65 mesh, more preferably 40-60 mesh, more preferably 45-55 mesh, and most preferably 50 mesh.
5. The method as described in claim 1, characterized in that, In step (2), the activated carbon includes activated carbon for injection.
6. The method as described in claim 1, characterized in that, In step (2), the mass ratio of propolis to activated carbon is 1:(1-5), preferably 1:(1.5-4.0), more preferably 1:(2-3.5), even more preferably 1:(2.2-3.0), even more preferably 1:(2.4-2.8), and most preferably 1:2.
6.
7. The method as described in claim 1, characterized in that, The mass ratio of crude borneol in step (1) to propolis in step (2) is 1:(0.03-0.3), preferably 1:(0.05-0.2), more preferably 1:(0.05-0.15), even more preferably 1:(0.08-0.12), even more preferably 1:(0.09-0.11), and most preferably 1:0.095; and / or The mass ratio of crude borneol in step (1) to activated carbon in step (2) is 1:(0.1-0.5), preferably 1:(0.1-0.4), more preferably 1:(0.15-0.35), even more preferably 1:(0.2-0.3), even more preferably 1:(0.23-0.27), and most preferably 1:0.
25.
8. The method as described in claim 1, characterized in that, In step (2), the crystallization temperature is 3-10℃, preferably 4-8℃, more preferably 5-7℃, more preferably 5.5-6.5℃, more preferably 5.8-6.2℃, and most preferably 6℃; and In step (2), the crystallization time is 5-15 days, preferably 5-12 days, more preferably 6-12 days, more preferably 7-11 days, more preferably 8-10 days, and optimally 9 days.
9. A method for preparing pure borneol, characterized in that, The method includes the following steps: (1) Mix crude borneol with an organic solvent to obtain a crude borneol solution; (2) Add propolis and activated carbon to the crude borneol solution obtained in step (1), stir, filter, concentrate the filtrate under reduced pressure, crystallize the concentrated solution, filter, and dry the solid to obtain pure borneol.
10. A pure borneol product, characterized in that, The pure borneol is prepared by the method described in claim 9.