Method for preparing HMF by using tobacco stems as raw materials
By pretreating and extracting syrups and reacting in an organic-water biphasic system, the problems of tobacco stem waste treatment and 5-hydroxymethylfurfural production were successfully solved, and efficient and economical HMF preparation was achieved. Promote the high value-added utilization of waste in the tobacco industry.
Patent Information
- Application Number
- CN202411517240.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2025-02-14
AI Technical Summary
The tobacco stem waste generated in the tobacco industry is difficult to effectively deal with and utilize due to harmful components, which limits its application scope and makes it difficult to achieve efficient and economical 5-hydroxymethylfurfural (HMF) production in the prior art.
5-hydroxymethylfurfural was prepared by pretreating the tobacco stems, extracting mixed syrup, and reacting in an organic-water biphasic system. The method includes steps such as crushing tobacco stems, extracting sugar, syrup concentration and catalytic reaction.
It has achieved efficient preparation of 5-hydroxymethylfurfural using tobacco stems as raw materials, which has improved resource utilization, reduced production costs, and provided an environmentally friendly and economical high-value-added industrial path.
Smart Images
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Figure BDA0005107051660000042
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of waste recycling, and in particular relates to a method for preparing HMF by using tobacco stems as raw materials. Background Art
[0002] The tobacco industry generates a large amount of tobacco stem waste every year. Since tobacco stems contain nicotine, solanesol and other ingredients that are harmful to the growth of crops, they cannot be used directly as fertilizer like traditional crops such as Platycodon grandiflorum. Instead, discarded tobacco stems processed by traditional methods can only be added back to cigarettes in small quantities, which greatly limits the application of tobacco stems and their products. Therefore, there is an urgent need to find an eco-friendly tobacco stem processing method.
[0003] 5-Hydroxymethylfurfural (5-HMF), as an important biomass conversion platform compound, has broad application potential in the fields of energy, chemical industry and materials. Currently, sugar products from various sources or non-grain crops such as cassava are used as raw materials for the production of 5-HMF, which is also the main source of production costs. The total sugar content of dry tobacco stems is about 16%. After hydrolysis, the fructose and glucose contents that can be used to convert HMF are close to 11% and 4% respectively, accounting for the majority of the total sugar. A reasonable sugar extraction method can be used to obtain sugar more completely. Converting the syrup extracted from tobacco stems into 5-HMF will find a high value-added industry for tobacco stems, which are waste products in the tobacco industry. Summary of the invention
[0004] In view of the above problems, the object of the present invention is to provide a method for preparing HMF using tobacco stems as raw materials.
[0005] The invention uses tobacco stems as raw materials, pretreats the discarded tobacco stems to obtain mixed syrup, and reacts under the conditions of an organic-water two-phase system to obtain 5-hydroxymethylfurfural.
[0006] The specific technical solutions are as follows:
[0007] The present invention provides a method for preparing HMF using tobacco stems as raw materials, comprising the following steps:
[0008] 1) To extract sugar, the tobacco stems must be completely soaked first. The interior of the tobacco stems is highly absorbent, but the outer skin will slow down the penetration of liquid. The tobacco stems can be crushed into 5-16 mesh (1-4mm in diameter) to facilitate soaking and extraction. If the particles are too large, the sugar extraction rate will be low and the extraction will take a long time. If the particles are too small, it will be difficult to filter the tobacco stem residue. After crushing, sieve them for later use.
[0009] 2) Extracting sugar from tobacco stems: There are many ways to extract sugar from tobacco stems, including the following:
[0010] ① Boiling to extract sugar: Soak the crushed tobacco stems completely in water at 80-90℃ and keep them in a water bath for 1-2 hours. The sugar will dissolve in the water. The mass ratio of tobacco stems to water should be controlled at 1:2-4. After the extraction, filter out the tobacco stem residue. The tobacco stem residue can be pressed to completely squeeze out the filtrate, so as to obtain sugar more completely.
[0011] ② Ethanol-water extraction of sugar: The crushed tobacco stems are completely soaked in ethanol at 50-60°C and kept in a water bath for 1-2 hours. The mass ratio of tobacco stems to ethanol is 1:2-4. Ethanol can dissolve the nicotine solution that is not conducive to subsequent conversion, thereby improving the HMF conversion rate. During the process, it is necessary to cover and reduce the volatilization of ethanol. After the end, the ethanol is completely filtered out and can be reused. The treated tobacco stems are then boiled and extracted by the method of the first method to obtain tobacco stem sugar liquid;
[0012] ③ Ethanol-acid extraction of sugar: completely soak the crushed tobacco stems in 50-60℃ ethanol, keep in a water bath for 1-2 hours, the mass ratio of tobacco stems to ethanol is 1:2-4, and completely filter out the ethanol after the extraction. Completely soak the treated tobacco stems in 80-90℃ water, the mass ratio of tobacco stems to water is 1:2-4, and drip sulfuric acid to adjust the pH to 4-5. It is easier to destroy the fiber tissue under acidic conditions, so that the sugar is quickly dissolved. Keep in a water bath for 0.5-1 hour. After the extraction is completed, filter to obtain the tobacco stem sugar liquid;
[0013] ④ Ethanol-acid-membrane sugar extraction: After obtaining the tobacco stem sugar liquid according to the ③ ethanol-acid sugar extraction method, a nanofiltration membrane with a molecular retention rate of 30-60% is selected to filter the sugar liquid. The sugar liquid obtained by filtering with a nanofiltration membrane with a high retention rate has fewer impurities, and the yield in the reaction of preparing 5-hydroxymethylfurfural after concentration is higher, and 5-hydroxymethylfurfural with higher purity can be obtained; however, the membrane filtering takes a long time, and the time consumption is proportional to the molecular retention rate.
[0014] 3) Concentration of tobacco stem syrup and determination of sugar content: The tobacco stem syrup obtained by different extraction methods is evaporated and concentrated to obtain tobacco stem syrup with high sugar content. In order to improve production efficiency, the tobacco stem syrup needs to be concentrated to a fructose mass fraction greater than 25%. The sugar content is determined by hydrolysis method. Take 1g of concentrated solution and add 20mL of water. Add sulfuric acid to adjust the pH to about 1. Stir at 90°C in a reactor for 90 minutes to carry out hydrolysis reaction. After the hydrolysis is completed, the fructose and glucose contents are determined.
[0015] 4) Preparation of 5-hydroxymethylfurfural from tobacco stem syrup: p-toluenesulfonic acid and aluminum chloride are selected as catalysts, tetrahydrofuran is selected as organic solvent, the mass ratio of organic solvent to tobacco stem syrup is 3-1:1, and the mass of the catalyst accounts for 1-5% of the total mass of tobacco stem syrup and organic solvent.
[0016] Reaction conditions: a pressure-resistant autoclave reactor is selected as the reaction vessel, the internal temperature of the reactor is preferably 130-140°C (100-150°C can react to produce 5-HMF, and considering the reaction rate, energy consumption and prevention of by-products, 130-140°C is preferred), the reaction time is 40-80 minutes, and appropriate adjustments are made according to the heating time. During the reaction, attention should be paid to the system pressure and temperature fluctuations. After the reaction, the reaction liquid is subjected to rotary evaporation to obtain 5-HMF with higher purity.
[0017] The beneficial effects of the present invention are:
[0018] A higher yield of 5-hydroxymethylfurfural can be obtained in an organic-water two-phase system using tobacco stem syrup as raw material. The preparation process is simple, the feeding is convenient, and the tobacco stem raw material is cheap. Compared with fructose, glucose and other non-grain crops as reaction raw materials, it has higher economic benefits and realizes resource utilization. DETAILED DESCRIPTION
[0019] The present invention is further described below in conjunction with embodiments, but the protection scope of the present invention is not limited thereto.
[0020] Example 1
[0021] Take 1000g of dry tobacco stems and grind them into powder to 5-16 mesh, sieve, retain the tobacco stem particles with a particle size of 5-16 mesh, mix them evenly, and take 5g of tobacco stem particles for component sugar content analysis. Put 5g of tobacco stem particles into a microreactor, add 10g of 72% sulfuric acid water, heat and stir at 120℃ for 45min. Under this reaction condition, the polysaccharides in the tobacco stems can be completely converted into monosaccharides, which is convenient for testing the total sugar content. The fructose content was tested to be 11.12% and the glucose content was 4.06%.
[0022] Take another 5 portions of 100 g and extract sugar according to the methods of water boiling extraction, ethanol-water extraction, ethanol-acid extraction, ethanol-acid-membrane extraction (30% retention rate), and ethanol-acid-membrane extraction (60% retention rate).
[0023] The specific steps are:
[0024] ① Boiling to extract sugar: Soak 100g of crushed tobacco stems completely in 90℃ water and keep in a water bath for 1.5 hours. The mass ratio of tobacco stems to water is controlled at 1:3 (the amount of water used is 300g). After the extraction is completed, filter out the tobacco stem residue. The tobacco stem residue can be pressed to completely press out the filtrate to obtain sugar more completely.
[0025] ② Ethanol-water extraction of sugar: 100g of crushed tobacco stems are completely soaked in 60°C ethanol and kept in a water bath for 1.5 hours. The mass ratio of tobacco stems to ethanol is 1:3 (the amount of ethanol used is 300g). After the end, the ethanol is completely filtered out and can be reused. The treated tobacco stems are then boiled and extracted by the method of the first method to obtain tobacco stem sugar liquid;
[0026] ③ Ethanol-acid extraction of sugar: 100g of crushed tobacco stems are completely soaked in 60℃ ethanol, kept in a water bath for 1.5 hours, the mass ratio of tobacco stems to ethanol is 1:3 (the amount of ethanol used is 300g), and the ethanol is completely filtered out after the extraction, and the treated tobacco stems are completely soaked in 90℃ water, the mass ratio of tobacco stems to water is 1:3 (the amount of water used is 300g), sulfuric acid is dripped into it to adjust the pH to 4, and kept in a water bath for 1 hour. After the extraction is completed, filter to obtain tobacco stem sugar liquid;
[0027] ④ After obtaining tobacco stem sugar liquid according to the ③ ethanol-acid sugar extraction method, a nanofiltration membrane with a molecular retention rate of 30-60% is selected to filter the sugar liquid.
[0028] The tobacco stem residue was filtered to obtain sugar solution. The sugar content of different extraction methods was determined by hydrolysis method, and the sugar yield was calculated (sugar yield = sugar mass / tobacco stem mass). The results are shown in Table 1.
[0029] Table 1 Summary of sugar content obtained by different extraction methods
[0030]
[0031] The fructose content of this batch of tobacco stems is 11.12%, and the glucose content is 4.06%. Comparing the sugar yields of different extraction methods in Table 1, in general, several methods can effectively obtain sugar from tobacco stems, but membrane may cause some sugar loss, but syrup with less impurities can be obtained. The tobacco stem sugar liquid obtained by different methods is concentrated to obtain tobacco stem syrup, and the fructose and glucose contents in the tobacco stem syrup are measured to ensure that the fructose content of the tobacco stem syrup obtained by different methods is greater than 25%.
[0032] Example 2
[0033] Take tobacco stem syrup with a fructose mass fraction of 25% as the reaction raw material (if the fructose content is greater than 25%, water can be added to adjust it to 25% in proportion for easy comparison and calculation), weigh 10g of tobacco stem syrup, 20g of tetrahydrofuran, add 0.5g of p-toluenesulfonic acid and 0.2g of aluminum chloride hexahydrate in a 50ml pressure reactor, maintain 140℃, 800r / min, 60min. Calculate the yield of 5-hydroxymethylfurfural (calculated based on fructose content). The results are shown in Table 2.
[0034] Table 2 Summary of yields of syrups extracted by different extraction methods for preparing 5-hydroxymethylfurfural
[0035]
[0036]
[0037] It can be found from Table 2 that the tobacco stem syrup treated with ethanol has a higher 5-hydroxymethylfurfural yield, and the yield is more significantly improved after membrane treatment.
Claims
1. A method for preparing HMF using tobacco stems as raw materials, characterized in that: The steps include: 1) Crush the tobacco stems: Crush the tobacco stems into 5-16 meshes and set aside; 2) Extracting sugar from tobacco stems: extracting sugar liquid from tobacco stems, and concentrating the sugar liquid by evaporation until the fructose content is greater than 25% to obtain tobacco stem syrup, and determining the fructose and glucose content by hydrolysis method; 3) Preparation of 5-hydroxymethylfurfural from tobacco stem syrup: A pressure-resistant autoclave reactor is selected as a reaction vessel, p-toluenesulfonic acid and aluminum chloride are used as catalysts, tetrahydrofuran is used as an organic solvent, and tobacco stem syrup is used as a raw material to carry out the reaction. After the reaction is completed, the reaction solution is subjected to rotary evaporation to obtain 5-hydroxymethylfurfural.
2. A method for preparing HMF using tobacco stems as raw materials according to claim 1, characterized in that: In step 2), the sugar solution is extracted from the tobacco stems by boiling the sugar. The specific operation process is: completely soak the crushed tobacco stems in 80-90°C water, keep the water bath for 1-2 hours, and the sugar is dissolved in the water. After the extraction is completed, the tobacco stem residue is filtered out, and the filtrate is completely pressed out to obtain the tobacco stem sugar solution.
3. A method for preparing HMF using tobacco stems as raw materials according to claim 2, characterized in that: The mass ratio of tobacco stems to water is 1:2-4.
4. The method for preparing HMF using tobacco stems as raw materials according to claim 1, characterized in that: In step 2), the sugar solution is extracted from the tobacco stems by ethanol-water extraction of sugar. The specific operation process is: the crushed tobacco stems are completely soaked in 50-60°C ethanol, kept in a water bath for 1-2 hours to dissolve the nicotine, and the ethanol is completely filtered out after the end. Then, the tobacco stems treated with ethanol are completely soaked in 80-90°C water, kept in a water bath for 1-2 hours, and the sugar is dissolved in the water. After the extraction is completed, the tobacco stem residue is filtered out, and the filtrate is completely pressed out by filtering to obtain the tobacco stem sugar solution.
5. A method for preparing HMF using tobacco stems as raw materials according to claim 4, characterized in that: The mass ratio of tobacco stems to ethanol is 1:2-4.
6. The method for preparing HMF using tobacco stems as raw materials according to claim 1, characterized in that: In step 2), the sugar solution is extracted from the tobacco stems by ethanol-acid extraction of sugar, and the specific operation process is: the crushed tobacco stems are completely soaked in ethanol at 50-60°C, kept in a water bath for 1-2 hours, nicotine is dissolved, and the ethanol is completely filtered out after the end, the tobacco stems treated with ethanol are completely soaked in water at 80-90°C, sulfuric acid is dripped into it to adjust the pH to 4-5, and kept in a water bath for 0.5-1 hour. After the extraction is completed, the tobacco stem residue is filtered out, and the filtrate is completely pressed out by filtering to obtain the tobacco stem sugar solution.
7. A method for preparing HMF using tobacco stems as raw materials according to claim 6, characterized in that: After the extraction, the sugar solution is filtered using a nanofiltration membrane with a molecular retention rate of 30-60%.
8. The method for preparing HMF using tobacco stems as raw materials according to claim 1, characterized in that: In step 3), the mass ratio of the organic solvent to the tobacco stem syrup is 3-1:1, and the mass of the catalyst accounts for 1-5% of the total mass of the tobacco stem syrup and the organic solvent.
9. The method for preparing HMF using tobacco stems as raw materials according to claim 1, characterized in that: The reaction temperature of step 3) is 130-140°C, and the reaction time is 40-80min.