Process for the isolation of terpinolene from oil of cinnamomum camphora

Abstract

This invention discloses a method for separating terpinene from camphor oil. The method utilizes the byproducts after separating eucalyptol from camphor oil. Camphor oil is subjected to vacuum distillation to release components, yielding passivated eucalyptol liquid and byproducts. The passivated eucalyptol liquid is then crystallized using a melt crystallization method to obtain more passivated eucalyptol and byproducts. The byproducts are fed into a distillation column for further distillation. The byproducts are coarsely separated in the distillation column using corrugated packing. After coarse separation, terpinene with a purity of 80% is obtained. The 80% purity terpinene is then purified by molecular distillation to obtain 98% purity terpinene. This method aims to improve the problem of low added value of byproducts and the tendency of terpinene to polymerize during atmospheric pressure separation, making it difficult to improve purity, when comprehensively utilizing camphor oil resources.

Description

Technical Field

[0001] This invention relates to the utilization of camphor oil resources, and more specifically to a method for separating terpenoid oil from camphor oil. Background Technology

[0002] Cinnamomum camphora is a tree species belonging to the genus Cinnamomum in the family Lauraceae. With the advancement of science and technology, Cinnamomum camphora can now be planted and cultivated on a large scale, resulting in relatively abundant Cinnamomum camphora resources. The main components of Cinnamomum camphora essential oil include alcohols, hydrocarbons, esters, and aldehydes. The alcohols are mainly 1,8-cineole and α-terpineol, while the hydrocarbons are mainly terpenes, including γ-terpinene, α-pinene, and caryophyllene.

[0003] Current market demand and the development trend of camphor tree resources are mainly focused on the extraction of camphor tree essential oil and the separation technology of eucalyptol. Terpinene is one of the trace components in camphor tree oil, with a content of 1% to 2%. Currently, for this product with relatively low content, a secondary separation extraction method using atmospheric pressure is generally used. However, this separation process is prone to polymerization, making it difficult to improve purity. Consequently, in the entire camphor tree development process, a large amount of residue after camphor tree essential oil extraction may not be fully utilized. Therefore, based on the existing camphor tree resources, it is worthwhile to study ways to improve the utilization of camphor tree resources. Summary of the Invention

[0004] The purpose of this invention is to provide a method for separating terpenoids from camphor oil, in order to improve the problem that the added value of by-products is low when camphor oil resources are comprehensively utilized, and that terpenoids are prone to polymerization during atmospheric pressure separation, making it difficult to improve purity.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for separating terpinene from camphor oil, wherein the separation method is used for the secondary utilization of the by-product after separating eucalyptol from camphor oil, comprising the following steps: Step A, raw material processing, refining camphor branches and leaves, and obtaining camphor oil after steam distillation, condensation, and oil-water separation; Step B, eucalyptol preparation, subjecting camphor oil to vacuum distillation, the vacuum distillation being used to release components, obtaining passivated eucalyptol liquid and by-product, the passivated eucalyptol liquid being crystallized by melt crystallization to obtain passivated eucalyptol and by-product, the passivated eucalyptol being purified by extraction; Step C, secondary processing of by-product, feeding the by-product into a distillation column for distillation, the by-product being coarsely separated in the distillation column by corrugated packing, obtaining terpinene with a purity of 80% after coarse separation in the distillation column; Step D, terpinene purification, purifying the 80% pure terpinene by molecular distillation to obtain terpinene with a purity of over 98%.

[0007] Furthermore, the above-mentioned vacuum distillation is carried out at a temperature of 170 to 190 degrees Celsius.

[0008] Furthermore, the corrugated packing installed in the distillation column is mesh-like, and the material of the corrugated packing is stainless steel.

[0009] Furthermore, when the above-mentioned distillation column processes the waste material, the packing height of the corrugated packing is 3m, and the reflux ratio of the above-mentioned distillation column is set to 1:6.

[0010] Furthermore, the cooling rate and sweating rate of the above-mentioned melting crystallization are both 4 degrees Celsius per hour, and the crystallization termination temperature of the above-mentioned melting crystallization is -30 degrees Celsius.

[0011] Furthermore, the distillation temperature during the above molecular distillation is 50-60℃, the distillation pressure is 100-150 Pa, the feed rate is 2 mL / min, and the scraper rotation speed is 100-150 r / min.

[0012] Compared with the prior art, the beneficial effects of the present invention are at least as follows:

[0013] This invention obtains eucalyptol from camphor oil through vacuum distillation, and improves the purity of eucalyptol through melt crystallization. The by-products after eucalyptol separation undergo secondary processing. A stainless steel wire mesh corrugated packing in a distillation column is used for coarse separation of the by-products, yielding a liquid containing 80% terpinene. Molecular distillation is then used to purify the liquid, obtaining a terpinene product with 98% purity. This allows for comprehensive utilization of camphor oil resources and significantly increases the added value of the by-products. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the background technology and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0015] One embodiment of the present invention is a method for separating terpenoid oil from camphor oil. This method is used to reuse the byproducts after separating eucalyptol from camphor oil, and includes the following steps:

[0016] Step A, raw material processing: Camphor tree branches and leaves are refined, and camphor oil is obtained through steam distillation, condensation, and oil-water separation. Since eucalyptol essential oil mainly comes from plants, and camphor tree essential oil is already rich in eucalyptol as the primary component, followed by α-terpineol, the typical processing of camphor tree leaves results in an essential oil yield between 3.8% and 5%. However, the eucalyptol content in crude camphor tree essential oil is close to 60%. Therefore, using camphor tree for camphor oil extraction is the preferred method for eucalyptol extraction.

[0017] Steam distillation is chosen because it requires less equipment and is easy to operate. In steam distillation, the plant material used as raw material (d) may mix with water. Direct contact between the essential oils and water during heating can cause off-flavors in the essential oils. Furthermore, the complex composition of essential oils from camphor tree branches and leaves means some components are prone to chemical changes or oxidation, potentially dissolving in water. Therefore, steam distillation avoids direct contact between the raw material and water, preventing it from suspending in the aqueous solution. This not only increases the yield of essential oils but also minimizes the impact of heating on the oil's composition, reducing the influence of reflux and thus improving the quality of the essential oils.

[0018] The analysis of camphor oil can be performed using a gas chromatography-mass spectrometry (GC-MS) system. The operating conditions are as follows: capillary quartz column (0.25 x 0.25 x 30 mm), vaporization chamber and injection temperature set to 230°C and 280°C respectively. The temperature program is set as follows: first maintain 60°C for 5 minutes, then increase the temperature from 60°C to 120°C at a rate of 10°C per minute, maintain 120°C for 5 minutes, then increase the temperature to 200°C at the same rate of 10°C and maintain for 5 minutes, and finally increase the temperature to 280°C at the same rate and maintain for 15 minutes. The carrier gas is high-purity helium, and the gas flow rate is 1.0 ml per minute. The camphor oil sample is diluted in diethyl ether at a dilution ratio of 1:100 (V / V) and a split ratio of 1:2. The mass spectrometry conditions are: electron bombardment ion source; electron energy of 70 eV; atomic weight range of 15 to 500 amu.

[0019] Step B involves preparing eucalyptol by vacuum distilling camphor oil. This vacuum distillation releases the components, yielding passivated eucalyptol liquid and byproducts. The benzene / alcohol extract of camphor tree leaves not only has a high content of olefins but also contains various complex chemical components applicable to the pharmaceutical, fragrance, and chemical industries. To utilize these substances effectively, vacuum distillation is used to leverage the melting point changes of the substances. During the essential oil extraction process, low-boiling-point organic solvents such as diethyl ether, n-butane, and petroleum ether can be added. Continuous reflux extraction dissolves the essential oil in the organic solvent, and vacuum distillation recovers the organic solvent, thus obtaining the target components of the essential oil from the organic solvent. This process also effectively reduces interfering components in camphor oil.

[0020] The passivated eucalyptol liquid is crystallized using a melt crystallization method to obtain passivated eucalyptol and by-products. The passivated eucalyptol is then purified by extraction. Since essential oils often contain a large amount of the bioactive component eucalyptol, the separation of components in camphor oil mainly focuses on eucalyptol. Small molecule organic compounds in camphor oil are separated using a melt crystallization method to obtain eucalyptol. The melt crystallization method is based on the difference in freezing points between eucalyptol and other components in the camphor oil to be separated. By lowering the temperature, the compounds in the liquid mixture crystallize. The precipitated crystals and the remaining liquid, due to their different chemical compositions, achieve the separation and purification of the target substance.

[0021] The crystals precipitated during the freezing process are pure eucalyptol liquid, while impurities remain in the remaining molten residue, i.e., waste. No solvent can be added during the eucalyptol liquid precipitation process, and the product has high purity. The entire process is low-energy, safe, and highly clean.

[0022] Step C, secondary processing of by-products: The by-products are fed into a distillation column for distillation. The by-products are coarsely separated in the distillation column by corrugated packing. After coarse separation in the distillation column, terpene oil with a purity of 80% is obtained.

[0023] Step D: Purification of terpinene oil. Terpinene oil with a purity of 80% is purified by molecular distillation to obtain terpinene oil with a purity of 98%. The byproduct of separating eucalyptol from camphor oil is coarsely separated in a distillation column using corrugated packing, and then purified by molecular distillation; thus obtaining terpinene oil with a higher concentration.

[0024] It is worth noting that after the extraction of the target compound from the by-products, a large amount of residual biomass, such as residues, is often generated. If these are not comprehensively utilized, they will inevitably cause environmental pollution and waste of resources. Generally speaking, plant residues mainly contain hemicellulose and cellulose, which are high-molecular-weight substances that are difficult to dissolve in conventional solvents during the extraction process.

[0025] Therefore, after extracting camphor oil from camphor tree branches and leaves, the deoiled branches and leaves can be used to extract anthocyanins. The residue remaining after the by-products are roughly separated in a distillation column can be placed together with the residue from the extracted branches and leaves in a tubular vacuum furnace for pyrolysis. To avoid oxidation, nitrogen protective gas is introduced into the tube, and the nitrogen flow rate is controlled by adjusting the pressure reducing valve and the flow meter. The temperature of the tubular vacuum furnace is increased from room temperature to 400 degrees Celsius and maintained at that temperature for half a day, and then naturally cooled to room temperature to obtain a carbonized sample of the camphor oil material. The carbonized sample has catalytic activity and can be used in industry.

[0026] Furthermore, the aforementioned vacuum distillation is conducted at a temperature of 170 to 190 degrees Celsius. This temperature range ensures that eucalyptol is not accidentally distilled and is suitable for the precipitation of most substances in camphor oil. Furthermore, the corrugated packing installed in the distillation column is a mesh structure made of stainless steel. This mesh-like stainless steel corrugated packing ensures relative stability during the separation process, and the mesh structure allows for the coarse separation of by-products during distillation, thereby obtaining terpinene oil with a purity of 80%.

[0027] Furthermore, when processing the by-products in the aforementioned distillation column, the height of the corrugated packing is 3m, and the reflux ratio of the distillation column is set to 1:6. By setting the height and reflux ratio, the purity of the separated terpene oil is maintained. Specifically, comparative operations are prepared according to the above methods:

[0028] 500g of the residue from the separation of eucalyptol from camphor oil was added to a 1000mL three-necked flask. The residue was then distilled using a stainless steel wire mesh corrugated packed distillation column with a packing height of 3m. A reflux ratio of 1:6 and a vacuum of 0.08MPa were used to separate 225g of terpinene with a purity of 80.5%, referred to as Sample 1.

[0029] 1000g of the residue from the separation of eucalyptol from camphor oil was added to a 2000mL three-necked flask. Distillation was then carried out using a self-made stainless steel wire mesh corrugated packed distillation column with a packing height of 3m. A reflux ratio of 1:5 and a vacuum degree of 0.09MPa were used to separate 458g of terpinene with a purity of 79.6%, referred to as Sample 2.

[0030] 3000g of the by-product of separating eucalyptol from camphor oil was added to a 5000mL three-necked flask. Distillation was then carried out using a self-made stainless steel wire mesh corrugated packed distillation column with a packing height of 3m. A reflux ratio of 1:6 and a vacuum degree of 0.08MPa were used to separate 1347g of terpinene with a purity of 78.9%, referred to as Sample 3.

[0031] Furthermore, the cooling rate and sweating rate of the aforementioned melt crystallization are both 4 degrees Celsius per hour, and the crystallization termination temperature of the aforementioned melt crystallization is -30 degrees Celsius. Sweating is a thermal process involving the slow heating of the separated crude eucalyptol crystals. During sweating, a portion of the components accompanying the eucalyptol crystals slowly melts into a liquid state and is discharged.

[0032] It is worth noting that as the sweating rate increases during the sweating process, both the yield and purity of eucalyptol show a slow decreasing trend. If the sweating rate is too high and the sweating time is too short, it may lead to incomplete dissolution of other camphor essential oil components in the crude eucalyptol crystals, and may also cause the dissolution of some eucalyptol crystals, resulting in a lower yield and purity of eucalyptol. Considering that a lower sweating rate may lead to a longer sweating process, a cooling rate of 4 degrees Celsius per hour for both melting and crystallization is more stable.

[0033] Furthermore, the distillation temperature for the above molecular distillation is 50-60℃, the distillation pressure is 100-150 Pa, the feed rate is 2 mL / min, and the scraper rotation speed is 100-150 r / min.

[0034] The terpinene oil from sample 1 was further purified using a molecular distillation apparatus, with a distillation temperature of 60℃, a distillation pressure of 100 Pa, a feed rate of 2 mL / min, and a scraper rotation speed of 150 r / min. Finally, 164 g of terpinene oil with a purity of 97.8% was obtained. Although its purity was slightly lower than 98% terpinene oil, this was considered to be due to fluctuations caused by pressure and scraper rotation speed. By reducing the scraper rotation speed and increasing the pressure, the final product could still achieve a purity of 98%.

[0035] Sample 2 was further purified using a molecular distillation apparatus at a distillation temperature of 55℃, a distillation pressure of 160 Pa, a feed rate of 1.5 mL / min, and a scraper rotation speed of 150 r / min. Finally, 335 g of terpinene with a purity of 98.2% was obtained.

[0036] Sample 3 was further purified using a molecular distillation apparatus at a distillation temperature of 50℃, a distillation pressure of 150 Pa, a feed rate of 2 mL / min, and a scraper rotation speed of 100 r / min. Finally, 967 g of terpinene with a purity of 98.4% was obtained. This resulted in the final terpinene having a purity exceeding 98%.

[0037] In this specification, terms such as "one embodiment," "another embodiment," "embodiment," and "preferred embodiment" refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same term in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0038] Although the invention has been described herein with reference to several illustrative embodiments, it should be understood that many other modifications and implementations can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed herein. More specifically, various variations and modifications can be made to the components and / or layout of the subject matter combination within the scope of the disclosure, background, and claims. Besides variations and modifications to the components and / or layout, other uses will be apparent to those skilled in the art.

Claims

1. A method for separating terpenoid oil from camphor oil, wherein the separation method is used for the secondary utilization of the by-products after separating eucalyptol from camphor oil, characterized in that, Includes the following steps: Step A, raw material processing: the branches and leaves of camphor trees are refined and obtained by steam distillation, condensation and oil-water separation to obtain camphor oil; Step B, preparing eucalyptol, involves vacuum distilling camphor oil to release components, yielding purified eucalyptol liquid and by-products. The purified eucalyptol liquid is then crystallized using a melt crystallization method to obtain purified eucalyptol and by-products. The purified eucalyptol is further purified by extraction. Step C, secondary processing of by-products: The by-products are fed into a distillation column for distillation. The distillation column uses corrugated packing to perform coarse separation of the by-products. After coarse separation in the distillation column, terpene oil with a purity of 80% is obtained. Step D: Purification of terpinene. The terpinene with a purity of 80% is purified by molecular distillation to obtain terpinene with a purity of over 98%. The corrugated packing installed in the distillation column is mesh-like, and the material of the corrugated packing is stainless steel.

2. The method for separating terpenoids from camphor oil according to claim 1, characterized in that: The vacuum distillation is carried out at a temperature of 170 to 190 degrees Celsius.

3. The method for separating terpenoid oil from camphor oil according to claim 1, characterized in that: When the distillation column processes the waste material, the packing height of the corrugated packing is 3m, and the reflux ratio of the distillation column is set to 1:

6.

4. The method for separating terpenoids from camphor oil according to claim 1, characterized in that: The cooling rate and sweating rate of the molten crystallization are both 4 degrees Celsius per hour, and the crystallization termination temperature of the molten crystallization is -30 degrees Celsius.

5. The method for separating terpenoids from camphor oil according to claim 1, characterized in that: The distillation temperature during molecular distillation is 50-60℃, the distillation pressure is 100-150 Pa, the feed rate is 2 mL / min, and the scraper rotation speed is 100-150 r / min.