A method to increase the yield of crude artemisinin

Abstract

A method for increasing the yield of crude artemisinin, belonging to the field of artemisinin extraction technology, includes: an extraction step: adding Artemisia annua leaves to a petroleum ether solvent, and simultaneously extracting by heating and stirring, ultrasound or microwave; a separation step: performing liquid-solid separation by filtration or centrifugation to obtain an artemisinin extract containing artemisinin; a concentration step: evaporating and concentrating the artemisinin extract to obtain an artemisinin concentrate; a crystallization step: placing the artemisinin concentrate into a crystallization tank for crystallization, and filtering after crystallization to obtain the mother liquor and crude artemisinin; the crystallization tank is a cold and hot crystallization tank with both a cooling medium ring cavity and a heating medium ring cavity, which can rapidly cool the upper artemisinin extract while maintaining a constant temperature in the lower artemisinin extract, reducing impurities adhering to the low-temperature crystals, accelerating the crystallization speed and improving the crystallization recovery rate of crude artemisinin.

Description

Technical Field

[0001] This invention belongs to the field of artemisinin extraction technology, and in particular, a method for increasing the yield of crude artemisinin. Background Technology

[0002] Artemisinin is primarily extracted from plants. The effective components of traditional Chinese medicine are extracted by taking advantage of the differences in solubility of various ingredients in different solvents. How to extract artemisinin more efficiently while ensuring the purity of the product is a technical problem that needs to be solved in this field.

[0003] An existing artemisinin extraction process includes (1) drying of the raw material; (2) initial preparation of artemisinin: the treated raw material is extracted with petroleum ether and separated, the supernatant is eluted through a silica gel column, the resulting eluent is concentrated until crystals precipitate, and then crystallized in a crystallization tank for 15-20 hours. After crystallization, the crude artemisinin is obtained by filtration; (3) purification of artemisinin: the crude artemisinin obtained in step (2) is placed in an alcohol precipitation tank to dissolve and stand, the supernatant is coarsely filtered, the filtrate is concentrated, and after crystallization for 15-20 hours, the mother liquor is removed to obtain the refined artemisinin. Although this method saves energy and reduces consumption, the recovery rate of artemisinin is not high, especially the recovery rate of crude artemisinin, which is only about 80%, seriously affecting economic benefits. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for improving the recovery rate of crude artemisinin and the purity of refined artemisinin by rapidly cooling and maintaining a constant temperature at the crystallization position, thereby addressing the above-mentioned deficiencies.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is a method for increasing the yield of crude artemisinin, comprising: an extraction step: adding Artemisia annua leaves to a petroleum ether solvent, and simultaneously extracting by heating and stirring, ultrasound or microwave; a separation step: performing liquid-solid separation by filtration or centrifugation to obtain an artemisinin extract containing artemisinin; a concentration step: evaporating and concentrating the artemisinin extract to obtain an artemisinin concentrate; and a crystallization step: placing the artemisinin concentrate into a crystallization tank for crystallization, and filtering after crystallization to obtain the mother liquor and crude artemisinin.

[0006] The crystallization tank is a hot and cold crystallization tank, comprising a tank body and a support frame. The tank body is fixedly mounted on the support frame. The tank body is equipped with a motor, a transmission, a rotating shaft, a feed inlet, an exhaust outlet, a solvent inlet, stirring blades, a crystallization sieve plate, a liquid outlet, a material outlet, a refrigerant annular cavity, and a heating medium annular cavity. The tank body is vertically mounted on the support frame. The middle part of the tank body is a cylindrical shell, with domed protruding shells at both ends, referred to as the upper shell and the lower shell, respectively. The rotating shaft passes through the center of the upper shell and is located on the axis inside the tank body. The upper end of the rotating shaft is mounted on the transmission, which is mounted on the outer surface of the upper shell and connected to the motor. The motor is mounted on a separately provided bracket. The feed inlet, exhaust outlet, and solvent inlet are located on the upper shell. The stirring blades are mounted on the rotating shaft inside the tank body. The stirring blades are U-shaped single-layer stirring blades, with straight horizontal blades at the bottom and straight vertical blades on both sides. The straight vertical blades are connected by an arc-shaped transition. A mounting bracket is provided on the upper middle surface of the straight horizontal blades of the stirring blades, and this bracket is installed on the bottom end of the rotating shaft inside the tank. The crystallizing sieve plate is a disc plate, installed on the lower shell below the straight horizontal blades, so that the straight horizontal blades and the crystallizing sieve plate together form a crystallization space. The crystallizing sieve plate and the central part of the downwardly protruding lower shell together form a filtrate space. The drain port is located at the center of the lower shell for discharging the filtered filtrate. The material outlet is located on the lower shell between the straight horizontal blades and the crystallizing sieve plate for discharging crystals. The refrigerant annular cavity is arranged in a wrapping manner on the outer surface of the lower part of the cylindrical shell. The refrigerant annular cavity has a refrigerant inlet and a refrigerant outlet for rapidly cooling the Artemisia annua extract inside the tank. The heat medium annular cavity is attached to the lower shell in a ring shape, leaving space at the center of the lower shell. The heat medium annular cavity has a heat medium inlet and a heat medium outlet for maintaining a constant temperature in the lower part of the tank to prevent it from becoming too low.

[0007] This crystallization tank, which simultaneously features a cooling medium ring cavity and a heating medium ring cavity, allows for rapid cooling of the artemisinin extract in the upper part while maintaining a constant temperature in the lower part. This reduces the adhesion of impurities to the low-temperature crystals, accelerates the crystallization rate, and improves the recovery rate of crude artemisinin.

[0008] The refrigerant in the refrigerant ring cavity is chilled water, and its temperature is 5-10℃.

[0009] The heat medium in the heat medium annular cavity is hot water with a temperature of 60-80℃.

[0010] The artemisinin extract was crystallized in a crystallization tank at a temperature of N, where 10℃ < N < 20℃, and for a crystallization time of 6 hours.

[0011] Furthermore, a secondary crystallization step is included: the temperature inside the crystallization tank is heated, the mother liquor is filtered, 5-20L of petroleum ether solvent is added, and the mixture is transferred to the crystallization tank for secondary crystallization. After crystallization, the mixture is filtered to obtain crude artemisinin product obtained by secondary crystallization.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] (1) The crystallization tank is equipped with both a cooling medium ring chamber and a heating medium ring chamber, which can rapidly cool the artemisinin extract in the upper part and keep the artemisinin extract in the lower part at a constant temperature. This can reduce the adhesion of impurities to the low-temperature crystals, accelerate the crystallization speed, and improve the crystallization recovery rate of crude artemisinin.

[0014] (2) A U-shaped single-layer stirring blade is adopted, so that the flat horizontal blade at the bottom and the crystallization sieve plate installed on the lower shell together form a crystallization space. This crystallization space is located in the middle and lower part of the heat medium ring cavity, which can keep the temperature constant at this position.

[0015] (3) A U-shaped single-layer stirring blade is adopted, so that the straight vertical blades on both sides are close to the inner wall of the cylindrical shell, which can stir the artemisinin extract more thoroughly.

[0016] (4) Secondary crystallization was carried out using a hot and cold crystallization tank, which further improved the crystallization recovery rate of crude artemisinin.

[0017] (5) It can achieve a crystallization recovery rate of over 98% for crude artemisinin. After further crystallization and purification of the crude artemisinin,

[0018] Artemisinin products with a purity of over 96% can be obtained, and the artemisinin recovery rate reaches over 97%. Attached Figure Description

[0019] Figure 1 This is a side perspective view of the cold and hot crystallization tank in this invention.

[0020] Figure 2 This is a top view of the structure of the hot and cold crystallization tank in this invention.

[0021] Figure 3 This is a schematic diagram of the front structure of the crystallization sieve plate in this invention.

[0022] In the diagram: 1. Tank body, 2. Motor, 3. Transmission device, 4. Shaft, 5. Inlet, 6. Exhaust port, 7. Solvent inlet, 8. Stirring blade, 9. Crystallization sieve plate, 10. Drain, 11. Material outlet, 12. Refrigerant annular cavity, 13. Heat medium annular cavity, 14. Support frame, 15. Cylindrical shell, 16. Upper shell, 17. Lower shell, 18. Straight horizontal blade, 19. Straight vertical blade, 20. Refrigerant inlet, 21. Refrigerant outlet, 22. Heat medium inlet, 23. Heat medium outlet. Detailed Implementation

[0023] The present invention will be further described below with reference to the embodiments. The following embodiments are intended to illustrate the present invention and not to further limit the present invention, and should not be used to limit the scope of protection of the present invention.

[0024] Example 1.

[0025] The key to this invention lies in the rapid cooling of the artemisinin extract in the crystallization tank while maintaining a constant temperature at the crystallization point. The specific operation method is as follows: A method for increasing the yield of crude artemisinin, comprising:

[0026] S1: Extraction: Dry and pulverize the Artemisia annua leaves, pass them through a 40-mesh sieve to obtain Artemisia annua leaf powder; take 1 kg of Artemisia annua leaf powder and put it into 10-20 L of petroleum ether solvent, place it in a microwave ultrasonic synthesis extractor, and stir and extract it in an environment with a microwave frequency of 10-20 GHz, an ultrasonic frequency of 20-25 kHz, and a temperature of 30-40 ℃.

[0027] S2: Separation: Filter the solution using a filter to obtain an artemisinin extract containing artemisinin.

[0028] S3: Concentration: The artemisinin extract is evaporated and concentrated to obtain artemisinin concentrate.

[0029] S4: Crystallization: Artemisinin concentrate is placed in a crystallization tank for crystallization. After crystallization, the mother liquor and crude artemisinin are obtained by filtration. This is the key to the present invention. Existing crystallization tanks can only cool rapidly. If the cooling temperature is too low, impurities are easily attached to the crystals. If the cooling temperature is too high, the crystallization speed is slow and the crystallization rate is not high. Therefore, this solution develops a hot and cold crystallization tank, which allows the upper part of the tank to cool rapidly while the lower part maintains the constant temperature required for crystallization. This avoids impurities and enables rapid and efficient crystallization.

[0030] As shown in the figure, the hot and cold crystallization tank includes a tank body 1 and a support frame 14. The tank body 1 is fixedly mounted on the support frame 14. The tank body 1 is equipped with a motor 2, a transmission device 3, a rotating shaft 4, a feed inlet 5, an exhaust port 6, a solvent inlet 7, a stirring blade 8, a crystallization sieve plate 9, a liquid outlet 10, a material outlet 11, a refrigerant annular cavity 12, and a heating medium annular cavity 13. The tank body 1 is vertically mounted on the support frame 14. The middle part of the tank body 1 is a cylindrical shell 15. The upper and lower ends of the cylindrical shell 15 are dome-shaped shells, referred to as the upper shell 16 and the lower shell 17, respectively. The rotating shaft 4 passes through the center of the upper shell 16 and is located on the axis inside the tank body 1. The upper end of the rotating shaft 4 is mounted on the transmission device 3. The actuator 3 is mounted on the outer surface of the upper shell 16. The actuator 3 is connected to the motor 2, which is mounted on a separately provided bracket. The feed inlet 5, exhaust outlet 6, and solvent inlet 7 are located on the upper shell 16. The stirring blade 8 is mounted on the rotating shaft 4 inside the tank 1. Existing stirring blades are multiple layers of stirring blades mounted at different positions on the rotating shaft, resulting in very frequent stirring, which is not conducive to crystallization. Here, the stirring blade 8 is made into a U-shaped single-layer stirring blade. The bottom of this U-shaped single-layer stirring blade is a flat horizontal blade 18, and the two sides are flat vertical blades 19. The flat horizontal blades 18 and the flat vertical blades 19 are connected in an arc shape. The upper surface of the middle part of the flat horizontal blades 18 of the stirring blade 8 is provided with a mounting bracket. The mounting bracket is installed on the bottom end of the rotating shaft 4 inside the tank body 1; the crystallizing sieve plate 9 is a disc plate, which is installed on the lower shell 17 below the straight horizontal blades 18, so that the straight horizontal blades 18 and the crystallizing sieve plate 9 together form a crystallization space, and the crystallizing sieve plate 9 and the central part of the downwardly protruding lower shell 17 together form a filtrate space; the drain port 10 is located in the center of the lower shell 17 for discharging the filtered filtrate, and the material outlet 11 is located on the lower shell 17 between the straight horizontal blades 18 and the crystallizing sieve plate 9 for discharging crystals; the refrigerant annular cavity 12 is arranged in a surrounding shape on the outer surface of the lower part of the cylindrical shell 15, and the refrigerant annular cavity 12 is provided with a refrigerant inlet 20 and a refrigerant outlet 21 to control the temperature of the refrigerant liquid. The temperature is set to 5-10℃ for introducing refrigerant and rapidly cooling the artemisia extract inside the tank. The heating medium annular cavity 13 is annularly attached to the lower shell 17, leaving the center of the lower shell 17 exposed. The heating medium annular cavity 13 is provided with a heating medium inlet 22 and a heating medium outlet 23. The temperature of the heating medium is set to 60-80℃ for introducing the heating medium and keeping the artemisia extract in the lower part of the tank at a constant temperature to prevent it from getting too low. The temperature of the artemisinin concentrate in the crystallization tank is set to 10-20℃, and the crystallization time is changed to 6 hours. Then, it is filtered to separate the mother liquor and crude artemisinin. According to the measurement, the cold and hot crystallization tank crystallization method can crystallize 2-4% more crude artemisinin from the artemisinin concentrate each time, and the crystallization recovery rate is high.

[0031] Example 2.

[0032] The key to this invention lies in the rapid cooling of the artemisinin extract in the crystallization tank while maintaining a constant temperature at the crystallization point. The specific operation method is as follows: A method for increasing the yield of crude artemisinin, comprising:

[0033] S1: Extraction: Dry and pulverize the Artemisia annua leaves, pass them through a 40-mesh sieve to obtain Artemisia annua leaf powder; take 1 kg of Artemisia annua leaf powder and put it into 20-30 L of petroleum ether solvent, place it in a microwave ultrasonic synthesis extractor, and stir and extract it in an environment with a microwave frequency of 15-25 GHz, an ultrasonic frequency of 23-28 kHz, and a temperature of 40-50 ℃.

[0034] S2: Separation: Filter the solution using a filter to obtain an artemisinin extract containing artemisinin.

[0035] S3: Concentration: The artemisinin extract is evaporated and concentrated to obtain artemisinin concentrate.

[0036] S4: Crystallization: Artemisinin concentrate is added to a crystallization tank for crystallization. After crystallization, the solution is filtered to obtain mother liquor and crude artemisinin.

[0037] S5: Secondary crystallization: Heat the temperature inside the tank to 25-30℃, then filter the mother liquor, add 10-15L of petroleum ether solvent, and transfer it to a crystallization tank for secondary crystallization. After crystallization, filter to obtain crude artemisinin with secondary crystallization. According to measurements, the secondary crystallization method can crystallize 1-2% more crude artemisinin from the artemisinin concentrate each time.

[0038] Example 3.

[0039] The key to this invention lies in the rapid cooling of the artemisinin extract in the crystallization tank while maintaining a constant temperature at the crystallization point. The specific operation method is as follows: A method for increasing the yield of crude artemisinin, comprising:

[0040] S1: Extraction: Dry and pulverize the Artemisia annua leaves, pass them through a 40-mesh sieve to obtain Artemisia annua leaf powder; take 1 kg of Artemisia annua leaf powder and put it into 30-40 L of petroleum ether solvent, place it in a microwave ultrasonic synthesis extractor, and stir and extract it in an environment with a microwave frequency of 20-30 GHz, an ultrasonic frequency of 25-30 kHz, and a temperature of 50-60 ℃.

[0041] S2: Separation: Filter the solution using a filter to obtain an artemisinin extract containing artemisinin.

[0042] S3: Concentration: The artemisinin extract is evaporated and concentrated to obtain artemisinin concentrate.

[0043] S4: Crystallization: Artemisinin concentrate is added to a crystallization tank for crystallization. After crystallization, the solution is filtered to obtain mother liquor and crude artemisinin.

[0044] S5: Secondary crystallization: Heat the temperature inside the tank to 25-30℃, then filter the mother liquor, add 15-20L of petroleum ether solvent, and transfer it to a crystallization tank for secondary crystallization. After crystallization, filter to obtain crude artemisinin product with secondary crystallization.

[0045] Measurements showed that using a combination of hot and cold crystallization tanks and a secondary crystallization method, an additional 3-6% of crude artemisinin could be crystallized from the artemisinin concentrate each time. The entire plant could crystallize an additional 2-4 kg of crude artemisinin from the concentrate daily, with product quality meeting standards. The crystallization recovery rate of crude artemisinin was 98.3%. Further crystallization and purification of the crude artemisinin yielded a product with a purity of 98.8% and a recovery rate exceeding 97%.

Claims

1. A method for increasing the yield of crude artemisinin, comprising: Extraction steps: Artemisia annua leaves are added to petroleum ether solvent and extracted by heating and stirring, ultrasound or microwave. Separation steps: Liquid-solid separation is performed by filtration or centrifugation to obtain an artemisinin extract containing artemisinin; Concentration steps: The artemisinin extract is evaporated and concentrated to obtain an artemisinin concentrate; Crystallization step: The artemisinin concentrate is put into a crystallization tank for crystallization. After crystallization, the solution is filtered to obtain the mother liquor and crude artemisinin. The crystallization tank is a hot and cold crystallization tank, comprising a tank body and a support frame. The tank body is fixedly mounted on the support frame. The tank body is equipped with a motor, a transmission device, a rotating shaft, a feed inlet, an exhaust outlet, a solvent inlet, stirring blades, a crystallization sieve plate, a liquid outlet, a material outlet, a refrigerant annular cavity, and a heating medium annular cavity. The tank body is vertically mounted on the support frame. The middle part of the tank body is a cylindrical shell, with domed protruding shells at both ends, referred to as the upper shell and the lower shell, respectively. The rotating shaft passes through the center of the upper shell and is located on the axis inside the tank body. The upper end of the rotating shaft is mounted on the transmission device, which is mounted on the outer surface of the upper shell and connected to the motor. The motor is mounted on a separately provided bracket. The feed inlet, exhaust outlet, and solvent inlet are located on the upper shell. The stirring blades are mounted on the rotating shaft inside the tank body and are U-shaped single-layer stirring blades. The bottom of the single-layer stirring blade is a flat horizontal blade, and the sides are flat vertical blades. The flat horizontal blades and the flat vertical blades are connected by an arc-shaped transition. The upper surface of the middle part of the flat horizontal blades of the stirring blade is provided with a mounting bracket, which is installed on the bottom end of the rotating shaft inside the tank. The crystallizing sieve plate is a disc plate, which is installed on the lower shell below the flat horizontal blades, so that the flat horizontal blades and the crystallizing sieve plate together form a crystallization space. The crystallizing sieve plate and the center part of the downward protruding lower shell together form a filtrate space. The drain port is located in the center of the lower shell, and the material outlet is located on the lower shell between the flat horizontal blades and the crystallizing sieve plate. The refrigerant annular cavity is arranged in a wrapping shape on the outer surface of the lower part of the cylindrical shell. The refrigerant annular cavity is provided with a refrigerant inlet and a refrigerant outlet. The heat medium annular cavity is attached to the lower shell in a ring shape, leaving the center position of the lower shell open. The heat medium annular cavity is provided with a heat medium inlet and a heat medium outlet.

2. The method for increasing the yield of crude artemisinin according to claim 1, characterized in that... The refrigerant in the refrigerant ring cavity is chilled water, and its temperature is 5-10℃.

3. The method for increasing the yield of crude artemisinin according to claim 1, characterized in that... The heat medium in the heat medium ring cavity is hot water with a temperature of 60-80℃.

4. The method for increasing the yield of crude artemisinin according to claim 1, characterized in that... The artemisinin extract was crystallized in a crystallization tank at a temperature N of 10℃ < N < 20℃ for 6 hours.

5. The method for increasing the yield of crude artemisinin according to claim 1, characterized in that... It also includes a secondary crystallization step: the secondary crystallization step involves heating the temperature inside the hot and cold crystallization tank, filtering the mother liquor, adding 5-20L of petroleum ether solvent, transferring it together to the crystallization tank for secondary crystallization, filtering after crystallization to obtain crude artemisinin product with secondary crystallization.

Images