Refining and purifying process of natural camphor and application of refining and purifying process

Abstract

The invention relates to the field of natural camphor, in particular to a refining and purifying process and application of natural camphor. Comprising the following steps: washing crude camphor with hot water for 2-3 times, and drying to obtain pretreated camphor; a dehydrating agent is added into the pretreated camphor for dehydration treatment, and dehydrated camphor is obtained; washing the dehydrated camphor with pentane for 2-3 times, and drying to obtain camphor to be crystallized; the method comprises the following steps: adding camphor to be crystallized into a polar solvent, stirring for 10-20 minutes at the temperature of 50-60 DEG C, then recrystallizing for 15-30 minutes at the temperature of 0-10 DEG C, carrying out reduced-pressure suction filtration, and drying to obtain recrystallized camphor; carrying out sublimation and condensation on the recrystallized camphor at 170-185 DEG C; thus, refined camphor is obtained. The preparation method comprises the following steps: adding refined camphor, camphor oil, mica powder, paraffin, cyanoacrylate and lavender oil into acetone, stirring at 55-65 DEG C for 5-6 hours, casting and molding, cooling and solidifying, drying and packaging. And thus obtaining the camphor ball.

Description

Technical Field

[0001] The invention relates to the technical field of natural camphor, in particular to a refining and purification process of natural camphor and application thereof. Background Art

[0002] With the development of the times, the application of natural camphor in medicine, cosmetics, daily chemical products and other fields is becoming more and more extensive, and people's requirements for the purity and yield of natural camphor are becoming higher and higher.

[0003] Natural camphor not only has high medicinal value, but is also widely used in insect repellent, antiseptic, fragrance, etc. due to its unique physical and chemical properties. However, the extraction and refining and purification process of natural camphor faces many challenges. In the prior art, the refining and purification process of natural camphor is mainly sublimation. Although the operation is simple and no solvent is required for dissolution and separation, camphor still contains some impurities that are difficult to remove during the sublimation process. These impurities will affect the quality and performance of camphor, thereby limiting its application in certain fields.

[0004] In view of the shortcomings of the purification process of natural camphor in the prior art, it is of great significance to prepare a refined and purified natural camphor. Summary of the invention

[0005] The object of the present invention is to provide a refining and purification process of natural camphor and its application to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A refining and purification process of natural camphor: comprising the following steps:

[0008] Step 1: washing the crude camphor with hot water for 2 to 3 times and drying to obtain pretreated camphor;

[0009] Step 2: adding a dehydrating agent to the pretreated camphor for dehydration to obtain dehydrated camphor;

[0010] Step 3: washing the dehydrated camphor with pentane for 2 to 3 times and drying to obtain camphor to be crystallized;

[0011] Step 4: adding the camphor to be crystallized into a polar solvent and stirring at 50-60° C. for 10-20 minutes, then recrystallizing at 0-10° C. for 15-30 minutes, filtering under reduced pressure, and drying to obtain recrystallized camphor;

[0012] Step 5: subliming and condensing the recrystallized camphor at 170-185° C. to obtain refined camphor.

[0013] The purpose of pre-treating the crude camphor with hot water washing is to remove soluble impurities on the surface of the crude camphor and further improve the purity of the camphor. In addition, the hard components in the crude camphor can be softened and dispersed to facilitate subsequent processing and improve the stability and crystallization effect of the camphor.

[0014] More optimally, the polar solvent includes acetone and anhydrous ethanol in a mass ratio of 1:2 to 3.

[0015] More optimally, the solid-liquid mass ratio in the recrystallization is 1:1.7-1.9.

[0016] More optimally, the pressure parameter in the reduced pressure filtration is specifically: -0.08 to -0.09 MPa.

[0017] More optimally, the dehydrating agent accounts for 0.1-0.2 wt% of the total amount of pretreated camphor; the dehydrating agent includes phosphoric acid, anhydrous calcium chloride, and a modified surfactant in a mass ratio of 1.5-2:1:0.2-0.5.

[0018] More optimally, the preparation method of the modified surfactant is:

[0019] Step 1: under a nitrogen atmosphere, n-pentanoic acid and ethanolamine (primary) are mixed at 150-160° C. for 5-6 hours, and then ethanolamine (secondary) and 0.1-0.2 wt% sodium ethoxide are added again, reacted at 95-110° C. for 3-4 hours, purified, recrystallized, and dried to obtain n-pentanoic acid monoethanolamine;

[0020] Step 2: Add pentanoic acid monoethanolamine, diethylamine, phosphorus oxychloride, and dodecyldimethyl tertiary amine to dimethyl sulfoxide, ether, and acetonitrile, react at 0-5° C. for 4-5 hours, then react at 60-70° C. for 1-2 days, purify, recrystallize, and dry to obtain a modified surfactant.

[0021] In the first step, the hydroxyl group of n-pentanoic acid reacts with the amino group of ethanolamine to form amide and byproducts such as amino ester and amide ester. Therefore, it is necessary to first generate n-pentanoic acid ethanolamide and n-pentanoic acid amide ester under high temperature conditions, and then reduce the temperature to decompose the byproducts.

[0022] In a further scheme, in the second step, the hydroxyl group in the monoethanolamine of n-pentanoic acid undergoes a phosphorylation reaction with phosphorus oxychloride and introduces a phosphate group, which forms a synergistic effect with the phosphoric acid in the dehydrating agent, and then undergoes a quaternization reaction to introduce dodecyl dimethyl tertiary amine to obtain a modified surfactant.

[0023] More optimally, the raw materials of the pentanoic acid monoethanolamine include the following components: by mass, 6 to 8 parts of pentanoic acid, 5 to 6 parts of ethanolamine (primary), 1 to 2 parts of ethanolamine (secondary), and 0.2 to 0.5 parts of 0.1 to 0.2 wt% sodium ethoxide;

[0024] The raw materials of the modified surfactant include the following components: by mass, 5 to 7 parts of monoethanolamine n-pentanoate, 1 to 2 parts of diethylamine, 2 to 3 parts of phosphorus oxychloride, 3 to 4 parts of dodecyldimethyl tertiary amine, 15 to 20 parts of dimethyl sulfoxide, 10 to 15 parts of ether, and 8 to 12 parts of acetonitrile.

[0025] Among them, by adding a modified surfactant, phosphoric acid, and anhydrous calcium chloride to synthesize a dehydrating agent for camphor, some soluble impurities in camphor can be removed, and its purity can be further improved. Phosphoric acid has strong acidity and water absorption, and can quickly combine with the moisture in camphor to form phosphates, thereby achieving a dehydration effect; anhydrous calcium chloride can absorb residual moisture, further improving the dehydration efficiency; finally, the modified surfactant has good compatibility with camphor molecules and water molecules. Through its surface activity, the modified surfactant can reduce the interfacial tension between camphor and water, thereby promoting the separation of water molecules from camphor molecules and improving the dehydration efficiency. The phosphate group enhances the emulsification effect between the dehydrating agent and camphor, making it easier to absorb and remove moisture, and the three produce a synergistic effect. In addition, by introducing a pentane group in the modified surfactant, it can more effectively help subsequent pentane remove residual excess phosphate groups and further purify natural camphor.

[0026] More optimally, a refined camphor is prepared by a refining and purification process of natural camphor.

[0027] The invention discloses an application of natural camphor. The preparation of the camphor balls comprises the following steps: adding refined camphor, camphor oil, mica powder, paraffin, cyanoacrylate and lavender oil into acetone, stirring at 55-65 DEG C for 5-6 hours, casting and forming, cooling and solidifying, drying and packaging to obtain the camphor balls.

[0028] More optimally, by weight, 5 to 6 parts of refined camphor, 2 to 3 parts of camphor oil, 0.5 to 1 part of mica powder, 2 to 3 parts of paraffin, 1 to 2 parts of cyanoacrylate, 0.5 to 1.5 parts of lavender oil, and 40 to 50 parts of acetone.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. In the scheme, the excess impurities are first washed with hot water, and then the water is further removed with a dehydrating agent. Subsequently, the ester group and the excess impurities of camphor are removed with pentane to improve the purity. Then, the natural camphor is further purified by recrystallization, and finally, refined camphor is obtained by sublimation. Compared with the traditional sublimation method, the purity of camphor can be further improved, and the product quality of natural camphor can be improved.

[0031] 2. In the scheme, by preparing modified surfactants, introducing phosphate groups and water-based groups, hydrogen bonds can be formed with water molecules to improve dehydration efficiency, and the introduction of pentane groups can more effectively help subsequent pentane remove residual excess phosphate groups and further purify natural camphor. In addition, the modified surfactant can also form a synergistic effect with phosphoric acid and anhydrous calcium chloride to jointly improve the dehydration efficiency and further improve the purity of camphor. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that the following parts are by mass, and all raw materials involved in the present invention are purchased from manufacturers without any special restrictions. Examples include: In the following examples, the purity of n-valeric acid is 99%, the CAS number is 109-52-4, and it is purchased from Nanjing Sifanke Chemical Co., Ltd.; the purity of ethanolamine is 99%, the CAS number is 141-43-5, and it is purchased from Shandong Jinyueyuan New Materials Co., Ltd.

[0034] The polar solvent includes acetone and anhydrous ethanol in a mass ratio of 1:2.5.

[0035] The solid-liquid mass ratio in recrystallization is 1:1.8.

[0036] Embodiment 1: A refining and purification process of natural camphor comprises the following steps:

[0037] Step 1: Preparation of modified surfactant: (1) Under nitrogen atmosphere, 7 parts of n-pentanoic acid and 5.5 parts of ethanolamine (first time) were mixed at 155° C. for 5.5 hours, and then 1.5 parts of ethanolamine (second time) and 0.3 parts of 0.15 wt% sodium ethanolate were added again, and the mixture was reacted at 100° C. for 3.5 hours, purified, recrystallized, and dried to obtain n-pentanoic acid monoethanolamine; (2) 6 parts of n-pentanoic acid monoethanolamine, 1.5 parts of diethylamine, 2.5 parts of phosphorus oxychloride, and 3.5 parts of dodecyldimethyl tertiary amine were added to 17 parts of dimethyl sulfoxide, 13 parts of ether, and 10 parts of acetonitrile, and the mixture was reacted at 2° C. for 4.5 hours, and then reacted at 65° C. for 1.5 days, purified, recrystallized, and dried to obtain a modified surfactant;

[0038] Step 2: washing the crude camphor with hot water for 3 times and drying to obtain pretreated camphor;

[0039] Step 3: adding a dehydrating agent to the pretreated camphor for dehydration treatment, wherein the dehydrating agent comprises phosphoric acid, anhydrous calcium chloride, and a modified surfactant in a mass ratio of 1.8:1:0.4, and the dehydrating agent accounts for 0.15wt% of the total amount of the pretreated camphor to obtain dehydrated camphor;

[0040] Step 4: washing the dehydrated camphor with pentane for three times and drying to obtain camphor to be crystallized;

[0041] Step 5: adding the camphor to be crystallized into a polar solvent and stirring at 55° C. for 15 minutes, then recrystallizing at 5° C. for 25 minutes, filtering under reduced pressure at -0.08 MPa, and drying to obtain recrystallized camphor;

[0042] Step 6: sublime and condense the recrystallized camphor at 179° C. to obtain refined camphor.

[0043] Embodiment 2: A refining and purification process of natural camphor comprises the following steps:

[0044] Step 1: Preparation of modified surfactant: (1) Under nitrogen atmosphere, 6 parts of n-pentanoic acid and 5 parts of ethanolamine (once) were mixed at 150° C. for 5 hours, followed by adding 1 part of ethanolamine (secondary) and 0.2 parts of 0.1 wt% sodium ethanolate, reacting at 95° C. for 3 hours, purifying, recrystallizing and drying to obtain n-pentanoic acid monoethanolamine; (2) 5 parts of n-pentanoic acid monoethanolamine, 1 part of diethylamine, 2 parts of phosphorus oxychloride and 3 parts of dodecyldimethyl tertiary amine were added to 15 parts of dimethyl sulfoxide, 10 parts of ether and 8 parts of acetonitrile, reacting at 0° C. for 4 hours, followed by reacting at 60° C. for 1 day, purifying, recrystallizing and drying to obtain modified surfactant;

[0045] Step 2: washing the crude camphor with hot water for 3 times and drying to obtain pretreated camphor;

[0046] Step 3: adding a dehydrating agent to the pretreated camphor for dehydration treatment, wherein the dehydrating agent comprises phosphoric acid, anhydrous calcium chloride, and a modified surfactant in a mass ratio of 1.5:1:0.2, and the dehydrating agent accounts for 0.15wt% of the total amount of the pretreated camphor to obtain dehydrated camphor;

[0047] Step 4: washing the dehydrated camphor with pentane for three times and drying to obtain camphor to be crystallized;

[0048] Step 5: adding the camphor to be crystallized into a polar solvent and stirring at 55° C. for 15 minutes, then recrystallizing at 5° C. for 25 minutes, filtering under reduced pressure at -0.08 MPa, and drying to obtain recrystallized camphor;

[0049] Step 6: sublime and condense the recrystallized camphor at 179° C. to obtain refined camphor.

[0050] Embodiment 3: A refining and purification process of natural camphor comprises the following steps:

[0051] Step 1: Preparation of modified surfactant: (1) Under nitrogen atmosphere, 8 parts of n-pentanoic acid and 6 parts of ethanolamine (first time) were mixed at 160° C. for 6 hours, and then 2 parts of ethanolamine (second time) and 0.5 parts of 0.2 wt% sodium ethanolate were added again, reacted at 110° C. for 4 hours, purified, recrystallized, and dried to obtain n-pentanoic acid monoethanolamine; (2) 7 parts of n-pentanoic acid monoethanolamine, 2 parts of diethylamine, 3 parts of phosphorus oxychloride, and 4 parts of dodecyldimethyl tertiary amine were added to 20 parts of dimethyl sulfoxide, 15 parts of ether, and 12 parts of acetonitrile, reacted at 5° C. for 5 hours, and then reacted at 70° C. for 2 days, purified, recrystallized, and dried to obtain a modified surfactant;

[0052] Step 2: washing the crude camphor with hot water for 3 times and drying to obtain pretreated camphor;

[0053] Step 3: adding a dehydrating agent to the pretreated camphor for dehydration treatment, wherein the dehydrating agent comprises phosphoric acid, anhydrous calcium chloride, and a modified surfactant in a mass ratio of 2:1:0.5, and the dehydrating agent accounts for 0.15wt% of the total amount of the pretreated camphor to obtain dehydrated camphor;

[0054] Step 4: washing the dehydrated camphor with pentane for three times and drying to obtain camphor to be crystallized;

[0055] Step 5: adding the camphor to be crystallized into a polar solvent and stirring at 55° C. for 15 minutes, then recrystallizing at 5° C. for 25 minutes, filtering under reduced pressure at -0.08 MPa, and drying to obtain recrystallized camphor;

[0056] Step 6: sublime and condense the recrystallized camphor at 179° C. to obtain refined camphor.

[0057] Comparative Example 1: Based on Example 1, no hot water washing is used, and the other processes remain unchanged, specifically:

[0058] Step 1: Preparation of modified surfactant: (1) Under nitrogen atmosphere, 7 parts of n-pentanoic acid and 5.5 parts of ethanolamine (first time) were mixed at 155° C. for 5.5 hours, and then 1.5 parts of ethanolamine (second time) and 0.3 parts of 0.15 wt% sodium ethanolate were added again, and the mixture was reacted at 100° C. for 3.5 hours, purified, recrystallized, and dried to obtain n-pentanoic acid monoethanolamine; (2) 6 parts of n-pentanoic acid monoethanolamine, 1.5 parts of diethylamine, 2.5 parts of phosphorus oxychloride, and 3.5 parts of dodecyldimethyl tertiary amine were added to 17 parts of dimethyl sulfoxide, 13 parts of ether, and 10 parts of acetonitrile, and the mixture was reacted at 2° C. for 4.5 hours, and then reacted at 65° C. for 1.5 days, purified, recrystallized, and dried to obtain a modified surfactant;

[0059] Step 2: adding a dehydrating agent to the crude camphor for dehydration treatment, wherein the dehydrating agent comprises phosphoric acid, anhydrous calcium chloride, and a modified surfactant in a mass ratio of 1.8:1:0.4, and the dehydrating agent accounts for 0.15wt% of the total amount of the pretreated camphor to obtain dehydrated camphor;

[0060] Step 3: washing the dehydrated camphor with pentane for three times and drying to obtain camphor to be crystallized;

[0061] Step 4: adding the camphor to be crystallized into a polar solvent and stirring at 55° C. for 15 minutes, then recrystallizing at 5° C. for 25 minutes, filtering under reduced pressure at -0.08 MPa, and drying to obtain recrystallized camphor;

[0062] Step 5: sublime and condense the recrystallized camphor at 179° C. to obtain refined camphor.

[0063] Comparative Example 2: Based on Example 1, no modified surfactant was added, and the other processes remained unchanged, specifically:

[0064] Step 1: washing the crude camphor with hot water for 3 times and drying to obtain pretreated camphor;

[0065] Step 2: adding a dehydrating agent to the pretreated camphor for dehydration treatment, wherein the dehydrating agent comprises phosphoric acid and anhydrous calcium chloride in a mass ratio of 1.8:1, and the dehydrating agent accounts for 0.15wt% of the total amount of the pretreated camphor to obtain dehydrated camphor;

[0066] Step 3: washing the dehydrated camphor with pentane for three times and drying to obtain camphor to be crystallized;

[0067] Step 4: adding the camphor to be crystallized into a polar solvent and stirring at 55° C. for 15 minutes, then recrystallizing at 5° C. for 25 minutes, filtering under reduced pressure at -0.08 MPa, and drying to obtain recrystallized camphor;

[0068] Step 5: sublime and condense the recrystallized camphor at 179° C. to obtain refined camphor.

[0069] Comparative Example 3: Based on Example 1, pentane washing is not used, and the other processes remain unchanged, specifically:

[0070] Step 1: Preparation of modified surfactant: (1) Under nitrogen atmosphere, 7 parts of n-pentanoic acid and 5.5 parts of ethanolamine (first time) were mixed at 155° C. for 5.5 hours, and then 1.5 parts of ethanolamine (second time) and 0.3 parts of 0.15 wt% sodium ethanolate were added again, and the mixture was reacted at 100° C. for 3.5 hours, purified, recrystallized, and dried to obtain n-pentanoic acid monoethanolamine; (2) 6 parts of n-pentanoic acid monoethanolamine, 1.5 parts of diethylamine, 2.5 parts of phosphorus oxychloride, and 3.5 parts of dodecyldimethyl tertiary amine were added to 17 parts of dimethyl sulfoxide, 13 parts of ether, and 10 parts of acetonitrile, and the mixture was reacted at 2° C. for 4.5 hours, and then reacted at 65° C. for 1.5 days, purified, recrystallized, and dried to obtain a modified surfactant;

[0071] Step 2: washing the crude camphor with hot water for 3 times and drying to obtain pretreated camphor;

[0072] Step 3: adding a dehydrating agent to the pretreated camphor for dehydration treatment, wherein the dehydrating agent comprises phosphoric acid, anhydrous calcium chloride, and a modified surfactant in a mass ratio of 1.8:1:0.4, and the dehydrating agent accounts for 0.15wt% of the total amount of the pretreated camphor to obtain dehydrated camphor;

[0073] Step 4: adding dehydrated camphor to a polar solvent and stirring at 55° C. for 15 minutes, then recrystallizing at 5° C. for 25 minutes, filtering under reduced pressure at -0.08 MPa, and drying to obtain recrystallized camphor;

[0074] Step 5: sublime and condense the recrystallized camphor at 179° C. to obtain refined camphor.

[0075] Comparative Example 4: Based on Example 1, phosphoric acid was used as a dehydrating agent, and the rest of the process remained unchanged, specifically:

[0076] Step 1: washing the crude camphor with hot water for 3 times and drying to obtain pretreated camphor;

[0077] Step 2: adding phosphoric acid as a dehydrating agent to the pretreated camphor for dehydration treatment, wherein the dehydrating agent accounts for 0.15wt% of the total amount of the pretreated camphor to obtain dehydrated camphor;

[0078] Step 3: washing the dehydrated camphor with pentane for three times and drying to obtain camphor to be crystallized;

[0079] Step 4: adding the camphor to be crystallized into a polar solvent and stirring at 55° C. for 15 minutes, then recrystallizing at 5° C. for 25 minutes, filtering under reduced pressure at -0.08 MPa, and drying to obtain recrystallized camphor;

[0080] Step 5: sublime and condense the recrystallized camphor at 179° C. to obtain refined camphor.

[0081] Detection experiment: The refined camphor prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was subjected to performance testing: (1) Recrystallization yield test: The recrystallized camphor prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was subjected to recrystallization yield test, as shown in Table 1; (2) Camphor percentage content test: The recrystallized camphor prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was subjected to a GC heating program at 280° C. and a sampling volume of 0.5 μL under a nitrogen atmosphere to test the camphor percentage content, as shown in Table 1:

[0082]

[0083] Table 1

[0084] Example 4: An application of natural camphor, using the refined camphor obtained in Example 1 in the preparation of camphor balls, comprising the following steps:

[0085] 5.5 parts of refined camphor, 2.5 parts of camphor oil, 0.8 parts of mica powder, 2.5 parts of paraffin, 1.5 parts of cyanoacrylate and 1 part of lavender oil are added to 45 parts of acetone, stirred at 60°C for 5.5 hours, cast into shape, cooled and solidified, dried and packaged to obtain camphor balls.

[0086] Example 5: An application of natural camphor, using the refined camphor obtained in Example 1 in the preparation of camphor balls, comprising the following steps:

[0087] 5 parts of refined camphor, 2 parts of camphor oil, 0.5 parts of mica powder, 2 parts of paraffin, 1 part of cyanoacrylate, and 0.5 parts of lavender oil are added to 40 parts of acetone, stirred at 55°C for 5 hours, cast into shape, cooled and solidified, dried, and packaged to obtain camphor balls.

[0088] Example 6: An application of natural camphor, using the refined camphor obtained in Example 1 in the preparation of camphor balls, comprising the following steps:

[0089] 6 parts of refined camphor, 3 parts of camphor oil, 1 part of mica powder, 3 parts of paraffin, 2 parts of cyanoacrylate, and 1.5 parts of lavender oil are added to 50 parts of acetone, stirred at 65°C for 6 hours, cast into shape, cooled and solidified, dried, and packaged to obtain camphor balls.

[0090] Testing experiment: The mothballs prepared in Examples 4 to 6 were tested for their performance: (1) Pest test: The mothballs prepared in Examples 4 to 6 were filled with ten pests respectively. After fifteen days, the number of dead pests was observed, as shown in Table 2:

[0091] Examples Pest experiment (head) Example 4 8 Example 5 7 Example 6 9

[0092] Table 2

[0093] Result analysis: According to the analysis in Table 1, it can be seen that by first washing the excess impurities with hot water, then using a dehydrating agent to further remove water, and then using pentane to remove the ester group and the excess impurities of camphor, the purity is improved, and then recrystallization is used to further purify the natural camphor, and finally sublimation is performed to obtain refined camphor. Compared with the traditional sublimation method, the purity of camphor can be further improved, and the product quality of natural camphor can be improved; by preparing a modified surfactant, introducing a phosphate group and a water-based group, it can form hydrogen bonds with water molecules to improve the dehydration efficiency, and introducing a pentane group can more effectively help the subsequent pentane to remove the residual excess phosphate group and further purify the natural camphor. In addition, the modified surfactant can also form a synergistic effect with phosphoric acid and anhydrous calcium chloride to jointly improve the dehydration efficiency and further improve the purity of camphor;

[0094] According to the analysis of Table 2, it can be seen that the composition ratio of the refined camphor used in mothballs in Example 6 is the most suitable, and the refined camphor therein fully exerts the effect of insect repelling and insecticidal, and works together with other ingredients such as camphor oil and lavender oil to enhance the insect repellent and mothproofing effect of mothballs, while providing a fresh aroma. Among them, mica powder works together with other ingredients such as paraffin and cyanoacrylate to improve the overall performance of mothballs and make them more durable.

[0095] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A refining and purification process for natural camphor, characterized in that: The following steps are involved: Step 1: washing the crude camphor with hot water for 2 to 3 times and drying to obtain pretreated camphor; Step 2: adding a dehydrating agent to the pretreated camphor for dehydration to obtain dehydrated camphor; Step 3: washing the dehydrated camphor with pentane for 2 to 3 times and drying to obtain camphor to be crystallized; Step 4: adding the camphor to be crystallized into a polar solvent and stirring at 50-60° C. for 10-20 minutes, then recrystallizing at 0-10° C. for 15-30 minutes, filtering under reduced pressure, and drying to obtain recrystallized camphor; Step 5: subliming and condensing the recrystallized camphor at 170-185° C. to obtain refined camphor.

2. A refining and purification process for natural camphor according to claim 1, characterized in that: The polar solvent includes acetone and anhydrous ethanol in a mass ratio of 1:2-3.

3. A refining and purification process for natural camphor according to claim 1, characterized in that: The solid-liquid mass ratio in the recrystallization is 1:1.7-1.

9.

4. A refining and purification process for natural camphor according to claim 1, characterized in that: The specific process of the hydrothermal reaction is as follows: the pressure parameter in the reduced pressure filtration is specifically: -0.08 to -0.09 MPa.

5. A refining and purification process for natural camphor according to claim 1, characterized in that: The dehydrating agent accounts for 0.1-0.2wt% of the total amount of pretreated camphor; the dehydrating agent comprises phosphoric acid, anhydrous calcium chloride and a modified surfactant in a mass ratio of 1.5-2:1:0.2-0.

5.

6. A refining and purification process for natural camphor according to claim 5, characterized in that: The preparation method of the modified surfactant is: Step 1: under a nitrogen atmosphere, n-pentanoic acid and ethanolamine (primary) are mixed at 150-160° C. for 5-6 hours, and then ethanolamine (secondary) and 0.1-0.2 wt% sodium ethoxide are added again, reacted at 95-110° C. for 3-4 hours, purified, recrystallized, and dried to obtain n-pentanoic acid monoethanolamine; Step 2: Add pentanoic acid monoethanolamine, diethylamine, phosphorus oxychloride, and dodecyldimethyl tertiary amine to dimethyl sulfoxide, ether, and acetonitrile, react at 0-5° C. for 4-5 hours, then react at 60-70° C. for 1-2 days, purify, recrystallize, and dry to obtain a modified surfactant.

7. A refining and purification process for natural camphor according to claim 6, characterized in that: The raw materials of the monoethanolamine of n-pentanoic acid include the following components: by weight, 6 to 8 parts of n-pentanoic acid, 5 to 6 parts of ethanolamine (primary), 1 to 2 parts of ethanolamine (secondary), and 0.2 to 0.5 parts of 0.1 to 0.2 wt% sodium ethoxide; The raw materials of the modified surfactant include the following components: by mass, 5 to 7 parts of monoethanolamine n-pentanoate, 1 to 2 parts of diethylamine, 2 to 3 parts of phosphorus oxychloride, 3 to 4 parts of dodecyldimethyl tertiary amine, 15 to 20 parts of dimethyl sulfoxide, 10 to 15 parts of ether, and 8 to 12 parts of acetonitrile.

8. Refined camphor prepared according to the refining and purification process of natural camphor according to any one of claims 1 to 7.

9. An application of natural camphor, characterized in that: The refined camphor prepared according to claim 1 is used to prepare mothballs; the preparation of the mothballs comprises the following steps: adding refined camphor, camphor oil, mica powder, paraffin, cyanoacrylate and lavender oil to acetone, stirring at 55-65° C. for 5-6 hours, casting, cooling and solidifying, drying and packaging to obtain mothballs.

10. The use of natural camphor according to claim 9, characterized in that: The raw materials of the mothballs include the following components: by weight, 5-6 parts of refined camphor, 2-3 parts of camphor oil, 0.5-1 parts of mica powder, 2-3 parts of paraffin, 1-2 parts of cyanoacrylate, 0.5-1.5 parts of lavender oil, and 40-50 parts of acetone.

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