A method for preparing high purity nicotine from tobacco stems

Abstract

The present application relates to a kind of high-purity nicotine preparation method derived from tobacco stem, belong to plant extraction technical field.This method is for the large amount of tobacco stem waste produced in the process of tobacco planting and baking, proposes an efficient nicotine extraction method.By crushing tobacco stem, using acid aqueous solution for acidification treatment, then using alkaline solution to adjust pH value and carry out steam distillation, collect distillate.Subsequently, using reverse osmosis membrane concentration and molecular distillation technology for purification, obtain high-purity nicotine solution.This method does not use organic solvent, reduces the security risk, at the same time improves the extraction rate and purity of nicotine, purity can reach 95%~99%, extraction efficiency is more than 85%.In addition, the method uses membrane distillation process to reduce energy consumption, reduce the loss of active ingredients, and further remove impurities through molecular distillation technology, prevent nicotine degradation and oxidation deterioration.The implementation of the present application not only realizes the high value-added utilization of tobacco stem, but also improves the economic benefit, reduces the pollution to the environment.

Description

Technical Field

[0001] This invention belongs to the field of plant extraction technology, specifically relating to a method for extracting high-purity nicotine from tobacco stems. Background Technology

[0002] The tobacco planting and curing processes generate a large amount of tobacco stalks. These stalks contain substances such as nicotine, polysaccharides, and solanesol. These stalks are generally treated as field waste, resulting in resource waste and environmental pollution.

[0003] Nicotine, also known as natural nicotine, plays a vital role in the pharmaceutical, natural pesticide, fragrance, and chemical industries. It is a key raw material for manufacturing safe and effective smoking cessation products and e-cigarettes. There is strong market demand for nicotine with a purity of 95% or higher, with domestic and international market prices exceeding 1500 yuan per kilogram. Currently, it is mainly extracted and prepared from tobacco itself or waste products generated during the tobacco-making process, such as tobacco stems and leaves.

[0004] In the extraction, separation, and purification of nicotine, large amounts of organic solvents (petroleum ether, ethyl acetate, n-hexane, etc.) are typically used. Most of these organic solvents are hazardous chemicals, posing certain safety hazards and restrictions in their use; they are not suitable for industrial production. Summary of the Invention

[0005] This invention proposes an extraction process for nicotine from tobacco stems.

[0006] The present invention proposes an extraction process for extracting nicotine from tobacco stems, comprising the following steps: (1) Crush the tobacco stick to 10-50 mesh using a pulverizer; (2) Add an acidic aqueous solution with a mass concentration of 0.5% to 5% at a material-to-liquid ratio of 1:5 to 10, mix well, adjust the pH of the solution to 1 to 2, and let it stand for 2 to 5 hours; filter with a 100-mesh filter and collect the filtrate.

[0007] (3) Adjust the pH of the filtrate to 9-11 with an alkaline solution with a mass concentration of 10-20%; pass saturated steam through for distillation, collect the distillate, and collect approximately 3-5 times the mass of the tobacco sticks. (4) The distillate is transported to a reverse osmosis membrane concentrator for membrane concentration; under a pressure of 1.0 to 2.0 MPa, it is concentrated to a mass of 0.1 to 0.2 times that of the distillate, and the membrane concentrate is collected.

[0008] (5) The distillate is treated with a molecular distillation apparatus to remove water and impurities from the membrane concentrate, and the heavy components are collected to obtain a high-purity nicotine solution. The molecular distillation temperature is 80℃~100℃, the rotor speed is 200~400r / min, the vacuum pressure is 10~50mbar, and the cooling temperature is 10℃~20℃.

[0009] Specifically, the acidifying agent used in step (2) is one or two of sulfuric acid, hydrochloric acid, phosphoric acid, and citric acid, and the amount of acidifying agent used is 1% to 10% of the mass of the tobacco rod.

[0010] The alkalizing agent used in step (3) is one or two of sodium hydroxide, potassium hydroxide, calcium hydroxide, and ammonium hydroxide. The amount of alkalizing agent used is 1% to 10% of the mass of tobacco waste.

[0011] During the reverse osmosis membrane concentration in step (4), the pressure conditions are 1.0 to 2.0 MPa. The concentration factor is 0.1 to 0.2 times the mass of the distillate being treated.

[0012] The molecular distillation purification conditions described in step (5) are a distillation temperature of 80℃~100℃ and a vacuum pressure of 10~50mbar.

[0013] The main technical approach of this invention is as follows: Solid and free nicotine in tobacco stems are neutralized with an acid solution to generate nicotine salts; the nicotine solution is then extracted under alkaline conditions; saturated steam distillation is then performed to obtain a distillate containing nicotine; finally, membrane concentration and molecular distillation techniques are applied to obtain high-purity nicotine. This method can improve the extraction rate of nicotine from tobacco stems, achieving an extraction efficiency of over 85%, and the purity of nicotine can reach 95%–99%.

[0014] As described above, the extraction process for nicotine from tobacco pipes of the present invention has the following advantages: (1) This invention utilizes the nicotine component contained in tobacco stems for high-value-added processing, thereby improving economic benefits. The tobacco stems are recycled; during the preparation process, no organic solvent extraction is used, reducing safety hazards, reducing the leaching of impurities during the extraction of nicotine from tobacco stems, and improving the purity of nicotine; (2) In the distillate concentration process of the present invention, the membrane distillation process has lower energy consumption and milder processing conditions compared with conventional membrane concentration, thus reducing the loss of effective components in the distillate.

[0015] (3) Purification using molecular distillation technology can reduce harmful impurities in nicotine and prevent degradation and oxidation of nicotine during the distillation process, resulting in high-purity nicotine. Molecular distillation technology has advantages such as low operating temperature, low vacuum pressure, short heating time, high separation degree, high product yield, and low product energy consumption. Attached Figure Description Figure 1 High-purity nicotine gas chromatogram Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below through specific embodiments. It should be understood that the specific embodiments described in this section are only for explaining the present invention and are not intended to limit the present invention. Example

[0017] The method for preparing high-purity nicotine in this embodiment includes the following steps: (1) Use 1 kg of tobacco stem containing 0.6% (by mass) nicotine and grind it to a fineness of 10 mesh. The nicotine content of the tobacco stem is shown in Table 1.

[0018] Table 1 Data Processing Table for Chemical Components of Tobacco Leaves

[0019] (2) Add 7 kg of 1% (m / m) phosphoric acid solution to the crushed tobacco stick, stir evenly, let stand for 2 hours, filter with a 100-mesh filter, collect the filtrate; test the pH value of the filtrate to be 1.5.

[0020] (3) Add 700 g of 10% (m / m) sodium hydroxide aqueous solution to adjust the pH of the filtrate to 10; pass saturated steam for distillation and collect 3 kg of distillate; (4) The distillate is transferred to a reverse osmosis membrane concentrator for membrane concentration; under a pressure of 1.5 MPa, it is concentrated to 400 g, and the membrane concentrate is collected. The operating pressure of the reverse osmosis membrane is 1.4–2.0 MPa. (5) The membrane concentrate was added to the feeder of the molecular distillation apparatus for further separation and purification. The heavy components were collected, and 5.7 g of nicotine was obtained. Its gas chromatogram is shown in [Figure number missing]. Figure 1 The purity was 96.7%, and the yield was 90%. The distillation temperature was 95℃, the rotor speed was 380 r / min, the distillation pressure was 15 mbar, and the cooling temperature was 20℃. Example

[0022] The method for preparing high-purity nicotine in this embodiment includes the following steps: (1) Use 1 kg of tobacco stem containing 0.5% (by mass) nicotine and grind it to a fineness of 50 mesh.

[0023] (2) Add 9 kg of 3% (m / m) citric acid solution to the crushed tobacco stick, stir evenly, let stand for 5 hours, filter with a 100-mesh filter, collect the filtrate; test the pH value of the filtrate to be 1.1.

[0024] (3) Add 800 g of 10% (m / m) potassium hydroxide aqueous solution to adjust the pH of the filtrate to 10.8; pass saturated steam for distillation and collect 5 kg of distillate; (4) The distillate is transported to a reverse osmosis membrane concentrator for membrane concentration; under a pressure of 2.0 MPa, it is concentrated to 500 g and the membrane concentrate is collected.

[0025] (5) The membrane concentrate was added to the feeder of the molecular distillation equipment for further separation and purification. The heavy components were collected, and 4.4 g of nicotine was obtained. The purity was 97.4% and the yield was 88%. The distillation temperature was 85℃, the rotor speed was 300 r / min, the distillation pressure was 35 mbar, and the cooling temperature was 15℃. Example

[0026] The method for preparing high-purity nicotine in this embodiment includes the following steps: (1) Use 1 kg of tobacco stem containing 0.8% (by mass) nicotine and grind it to a fineness of 50 mesh.

[0027] (2) Add 5 kg of 2% (m / m) hydrochloric acid solution to the crushed tobacco stick, stir evenly, let stand for 5 hours, filter with a 100-mesh filter, collect the filtrate; test the pH value of the filtrate to be 1.0.

[0028] (3) Add 900 g of 10% (m / m) calcium hydroxide aqueous solution to adjust the pH of the filtrate to 11.0; pass saturated steam for distillation and collect 4 kg of distillate; (4) The distillate is transported to a reverse osmosis membrane concentrator for membrane concentration; under a pressure of 1.2 MPa, it is concentrated to 600 g and the membrane concentrate is collected.

[0029] (5) The membrane concentrate was added to the feeder of the molecular distillation equipment for further separation and purification. The heavy components were collected, and 7.3 g of nicotine was obtained. The purity was 97.5% and the yield was 91.25%. The distillation temperature was 100℃, the rotor speed was 200 r / min, the distillation pressure was 40 mbar, and the cooling temperature was 12℃.

[0030] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for extracting high-purity nicotine from tobacco pipes, characterized in that... Includes the following steps: (1) Crush the tobacco stem to 10 to 50 mesh; (2) Add an acidic aqueous solution with a mass concentration of 0.5% to 5% at a material-to-liquid ratio of 1:5 to 10, adjust the pH of the solution to 1 to 2, let it stand, filter, and collect the filtrate; (3) Adjust the pH of the filtrate to 9-11 using an alkaline solution with a mass concentration of 10% to 20%, perform steam distillation, and collect the distillate; (4) The distillate is concentrated to 0.1 to 0.2 times its mass using a reverse osmosis membrane concentrator; (5) The concentrate is treated with molecular distillation equipment and purified at 80℃~100℃, under a vacuum pressure of 10 to 50mbar, with a rotor speed of 200~400r / min and a cooling temperature of 10℃~20℃ to obtain a high-purity nicotine solution.

2. The method according to claim 1, characterized in that, The acidifying agent in the acidic aqueous solution is one or a combination of two of sulfuric acid, hydrochloric acid, phosphoric acid, or citric acid, and the amount of acidifying agent used is 1% to 10% of the mass of the tobacco rod.

3. The method according to claim 1, characterized in that, The alkalizing agent in the alkaline solution is one or a combination of two of sodium hydroxide, potassium hydroxide, calcium hydroxide, or ammonium hydroxide, and the amount of alkalizing agent used is 1% to 10% of the mass of the tobacco rod.

4. The method according to claim 1, characterized in that, The reverse osmosis membrane concentration step is carried out under a pressure of 1.0 to 2.0 MPa.

5. The method according to claim 1, characterized in that, The molecular distillation temperature is 80℃~100℃, the rotor speed is 200~400r / min, and the vacuum pressure is 10~50mbar.

6. The method according to claim 1, characterized in that, The nicotine purity in the nicotine solution obtained by the molecular distillation purification step reaches 95% to 99%.

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