Method for preparing furfural and / or levulinic acid

Abstract

The invention provides a method for preparing furfural and / or levulinic acid, and the method for preparing furfural and / or levulinic acid by using tobacco waste comprises the following steps: crushing a tobacco raw material, then mixing with sulfuric acid and solid acid, heating to react, and then separating to obtain a product. According to the method provided by the invention, the furfural and the levulinic acid in the tobacco waste are extracted by utilizing an acidic hydrothermal depolymerization method, so that the problem of low extraction rate of the furfural and the levulinic acid is solved, and the production cost is also reduced. The method has the advantages of low cost, high efficiency and large-scale popularization and application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biomass resource utilization, and particularly relates to a method for preparing furfural and / or levulinic acid. BACKGROUND

[0002] In today's society, environmental protection and sustainable utilization of resources have become the focus of global attention. With the continuous development of the tobacco industry, a large amount of tobacco waste has also been generated. If these tobacco wastes are not properly disposed of, they will not only cause serious pollution to the environment, but also waste valuable resources. Tobacco waste mainly includes tobacco stems, tobacco dust, tobacco ash, etc. At present, the main disposal methods for tobacco waste are landfilling and incineration. However, these disposal methods have many problems. Landfilling will occupy a large amount of land resources and may pollute the soil and groundwater; although incineration can reduce the volume of waste, it will produce a large amount of harmful gases and smoke, causing serious pollution to the atmospheric environment. At the same time, furfural and levulinic acid, as important chemical raw materials, have a wide range of applications in many fields. Furfural can be used in the synthesis of resins, medicines, pesticides, etc., and levulinic acid has important uses in fuel additives, spices, plastics, etc. Traditional methods for preparing furfural and levulinic acid mainly rely on fossil resources such as petroleum and coal. However, with the increasing depletion of fossil resources and the increasing environmental problems, it is particularly important to find a sustainable method for preparing furfural and levulinic acid.

[0003] In the prior art, CN110818716A discloses a method for preparing furfural from agricultural and forestry waste, but does not involve tobacco waste as raw material, and the reaction condition control is relatively simple. CN111995518A reports a process for preparing levulinic acid from lignocellulose, but requires the use of organic solvents, increasing the cost and environmental burden. At present, research on the resource utilization of tobacco waste mainly focuses on extracting nicotine or preparing organic fertilizer, and there is no systematic research on the preparation of furfural and levulinic acid.

[0004] Therefore, how to provide a method for efficiently utilizing tobacco waste to prepare furfural and levulinic acid has become a problem to be solved. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a method for preparing furfural and / or levulinic acid. The method provided by the present application uses an acid hydrothermal depolymerization method to extract furfural and levulinic acid from tobacco waste, not only solving the problem of low extraction rate of furfural and levulinic acid, but also reducing the production cost. The method has the advantages of low cost, high efficiency and large-scale application.

[0006] To achieve the purpose of the present application, the following technical solutions are adopted:

[0007] The present application provides a method for preparing furfural and / or levulinic acid, which utilizes tobacco waste to prepare furfural and / or levulinic acid, and comprises the following steps:

[0008] The tobacco raw material is crushed, then mixed with sulfuric acid and solid acid for heating reaction, and then the product is separated.

[0009] The above method uses an acidic hydrothermal depolymerization method to extract furfural and levulinic acid from tobacco waste, not only solving the problem of low extraction rate of furfural and levulinic acid, but also reducing the production cost. The method has the advantages of low cost, high efficiency, and can be widely applied.

[0010] Preferably, the tobacco raw material includes tobacco waste, which not only has the advantages of wide raw material sources and low production cost, but also can solve the pollution problem caused by tobacco waste, realizing the concept of green development and sustainable development.

[0011] Preferably, the part of the tobacco waste includes any one or a combination of at least two of tobacco leaves, tobacco stalks, tobacco stems, or tobacco roots.

[0012] Preferably, the particle size of the crushed tobacco raw material is 0.1-0.5mm, such as 0.1mm, 0.2mm, 0.3mm, 0.4mm or 0.5mm, but not limited to the above listed values, other values within the above range are also applicable.

[0013] Preferably, the tobacco raw material is dried after being crushed.

[0014] Preferably, the solid-liquid ratio of the tobacco raw material to sulfuric acid is 1:(2-10)g / mL, such as 1:2g / mL, 1:3g / mL, 1:4g / mL, 1:5g / mL, 1:6g / mL, 1:7g / mL, 1:8g / mL, 1:9g / mL or 1:10g / mL, but not limited to the above listed values, other values within the above range are also applicable.

[0015] Preferably, the mass fraction of the sulfuric acid is 2-11%, such as 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or 11%, but not limited to the above listed values, other values within the above range are also applicable.

[0016] Preferably, the addition amount of the solid acid is 1-3% of the mass of the tobacco raw material, such as 1%, 1.5%, 2%, 2.5% or 3%, but not limited to the above listed values, other values within the above range are also applicable.

[0017] Preferably, the solid acid comprises any one or a combination of at least two of HZSM-5 molecular sieve, HY molecular sieve, Hβ molecular sieve, acidic resin or acidic montmorillonite, preferably a combination of HZSM-5 molecular sieve and acidic montmorillonite.

[0018] The specific solid acid combination can significantly improve the reaction selectivity, reduce side reactions and improve product yield.

[0019] Preferably, the temperature rising reaction is carried out using a three-stage gradient temperature rising procedure, and the specific process is as follows:

[0020] 120-140℃ for 20-40min, then rising to 160-170℃ for 50-70min, and then rising to 180-190℃ for 20-40min.

[0021] Preferably, the rising rate is independently 1-25℃ / min.

[0022] The specific temperature rising procedure can effectively promote the hydrolysis and depolymerization of cellulose and hemicellulose in the tobacco raw material, and complete the conversion of furfural and acetic acid.

[0023] Preferably, the temperature rising reaction is carried out under an inert atmosphere.

[0024] Preferably, the separation is carried out using in-situ adsorption.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] The present application provides a method for preparing furfural and / or acetic acid, which uses an acidic hydrothermal depolymerization method to extract furfural and acetic acid from tobacco waste, not only solving the problem of low extraction rate of furfural and acetic acid, but also reducing the production cost; the method has the advantages of low cost, high efficiency and large-scale application. DETAILED DESCRIPTION

[0027] In order to further illustrate the technical means adopted by the present application and its effects, the technical solution of the present application will be further described below in combination with the preferred embodiments of the present application, but the present application is not limited in the scope of the embodiments.

[0028] Example 1

[0029] The present embodiment provides a method for preparing furfural and acetic acid, and the specific steps are as follows:

[0030] 1 g of tobacco stalks, which were crushed to a particle size of 0.2 mm, were dried at 80 °C for 10 h, mixed with 10 mL of a 5% sulfuric acid solution, and added to a reaction kettle with 2% of a mixed solid acid catalyst of HZSM-5 zeolite (Si / Al = 25) and acid montmorillonite (mass ratio 1:1). A nitrogen atmosphere was introduced at 1 MPa, the stirring rate was set to 800 rpm, and three stages of heating were performed in sequence: the first stage was 120 °C for 30 min, the second stage was 165 °C for 60 min, and the third stage was 185 °C for 30 min, with a heating rate of 20 °C / min.

[0031] After the reaction was completed, the reaction liquid was separated after cooling. The adsorbent was shaken at 70 °C for 1 h with anhydrous ethanol (1 g of adsorbent / 10 mL of ethanol), filtered, and the acetylpicolic acid yield was calculated using HPLC detection; the remaining furfural hydrolysate and lignin residue were separated by pressure filtration, the hydrolysate was separated by rectification, and the product was determined using high-performance liquid chromatography, with a furfural yield of 13.64% and an acetylpicolic acid yield of 11.22%.

[0032] Examples 2-6

[0033] Tobacco waste from different parts (tobacco leaves, tobacco stems, and tobacco roots) was used as the raw material, and the other conditions were the same as in Example 1 (Example 3 did not add a solid acid). The results are as follows:

[0034]

[0035] As can be seen from the above examples, the method provided by the present application can use various tobacco waste as raw materials to prepare furfural and acetylpicolic acid.

[0036] Examples 7-24

[0037] Referring to Example 1, the raw material was crushed waste tobacco stalks, and the difference was that the liquid-solid ratio of sulfuric acid to tobacco raw material and the mass fraction of sulfuric acid were different. The specific reaction parameters and the furfural yield of the product are as follows:

[0038]

[0039] Examples 25-43

[0040] Referring to Example 1, the raw material was crushed waste tobacco stalks, and the difference was that the three-stage holding time and the nitrogen pressure were different. The specific reaction parameters and the furfural and acetylpicolic acid yields of the product are shown in the table below. The raw material used was crushed tobacco stalks, and the sulfuric acid concentration used in the reaction was 5%, and the liquid-solid ratio was 10:1.

[0041]

[0042] Examples 44-56

[0043] Reference Example 1, except that the solid acid is different, the yield of furfural and acetic propionic acid is shown in the following table.

[0044] Example Solid acid catalyst Furfural yield (%) Levulinic acid yield (%) 44 Sulfonated carbon 8.21 7.35 45 HY 9.63 7.81 46 Acidic montmorillonite 9.67 10.92 47 HZSM-5 (360) 6.24 6.87 48 HZSM-5 (80) 7.69 8.24 49 HZSM-5 (50) 10.89 9.12 50 HZSM-5 (25) 10.13 9.84 51 Hβ 8.19 9.14 52 Amberlyst 35W 7.93 8.12 53 HZSM-5 (25) + sulfonated carbon 9.12 10.07 54 HZSM-5 (25) + HY 10.36 8.17 55 HZSM-5 (25) + Hβ 9.12 10.69 56 HZSM-5 (25) + Amberlyst 35W 8.14 10.01

[0045] Note: three-stage heating; 25, 50, 80, 360 are the Si / Al ratio in HZSM-5; the mass ratio of the two catalysts in the complex catalyst is 1:1. HZSM-5, Hβ, HY molecular sieve is purchased from Nankai Catalyst Factory; acid montmorillonite and Amberlyst 35W resin are purchased from Shanghai Maikelin Biotechnology Co., Ltd.; the preparation method of sulfonated carbon is: after drying, the commercial activated carbon (200 mesh, purchased from Shanghai Maikelin Biotechnology Co., Ltd.) is mixed with concentrated sulfuric acid at a mass ratio of 1:20, and reacted at 100°C for 24 hours. After the reaction is completed, it is washed to neutral with water, filtered and dried to obtain sulfonated carbon.

[0046] Examples 57-60

[0047] Reference Example 1, except that the three-stage heating rate is different, the specific reaction parameters and the yield of furfural and acetic propionic acid are shown in the table.

[0048] Example Temperature ramp (°C / min) o C / min) Furfural yield (%) Levulinic acid yield (%) 57 1 6.29 6.95 58 5 8.63 7.74 59 10 10.01 10.12 60 25 9.64 10.01

[0049] Example 61

[0050] Reference Example 1, the raw material is crushed waste straw, except that the specific process of three-stage heating is: the first stage is 185°C for 30 min, the second stage is 120°C for 30 min, and the third stage is 165°C for 60 min, and the temperature increasing rate is 20°C / min.

[0051] Example 62

[0052] Reference Example 1, the raw material is crushed waste straw, except that the specific process of three-stage heating is: the first stage is 165°C for 60 min, the second stage is 185°C for 30 min, and the third stage is 120°C for 30 min, and the temperature increasing rate is 20°C / min.

[0053] Example 63

[0054] Reference Example 1, the raw material is crushed waste straw, except that one-stage heating is used, and the temperature is 185°C for 120 min.

[0055] Example 64

[0056] Reference Example 1, the raw material is crushed waste straw, except that one-stage heating is used, and the temperature is 165°C for 120 min.

[0057] Example 65

[0058] Referring to Example 1, the raw material is crushed waste tobacco stalks. The difference is that a single heating stage is used, with the temperature held at 120°C for 120 minutes.

[0059] The results of Examples 61-65 are as follows:

[0060] Example Furfural yield (%) Levulinic acid yield (%) 61 7.63 6.12 62 7.24 5.91 63 6.36 6.24 64 8.16 7.15 65 4.51 5.04

[0061] The data above shows that by selecting a specific heating process and a specific solid acid, the present invention can effectively improve the yield of furfural and levulinic acid.

[0062] The applicant declares that the present invention illustrates the method for preparing furfural and / or levulinic acid through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0063] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0064] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A process for the preparation of furfural and / or levulinic acid, characterized in that, The method for preparing furfural and / or levulinic acid from tobacco waste comprises the following steps: The tobacco raw material is crushed, then mixed with sulfuric acid and solid acid for heating reaction, and then the product is separated.

2. The process for the production of furfural and / or levulinic acid according to claim 1, characterized in that, The tobacco raw material comprises tobacco waste. Preferably, the part of the tobacco waste comprises any one or a combination of at least two of tobacco leaves, tobacco stalks, tobacco stems or tobacco roots.

3. The process for the production of furfural and / or levulinic acid according to claim 1 or 2, characterized in that, The particle size of the crushed tobacco raw material is 0.1-0.5mm.

4. The process for the preparation of furfural and / or levulinic acid according to any one of claims 1 to 3, characterized in that, The crushed tobacco raw material is further dried.

5. The process for the preparation of furfural and / or levulinic acid according to any one of claims 1 to 4, characterized in that, The solid-liquid ratio of the tobacco raw material to sulfuric acid is 1:(2-10)g / mL.

6. The process for the preparation of furfural and / or levulinic acid according to any one of claims 1 to 5, characterized in that, The mass fraction of the sulfuric acid is 2-11%.

7. The process for the preparation of furfural and / or levulinic acid according to any one of claims 1 to 6, characterized in that, The addition amount of the solid acid is 1-3% of the mass of the tobacco raw material.

8. The process for the production of furfural and / or levulinic acid according to any one of claims 1 to 7, characterized in that, The solid acid comprises any one or a combination of at least two of HZSM-5 molecular sieve, HY molecular sieve, Hβ molecular sieve, acidic resin or acidic montmorillonite, preferably a combination of HZSM-5 molecular sieve and acidic montmorillonite.

9. The process for the production of furfural and / or levulinic acid according to any one of claims 1 to 8, characterized in that, The heating reaction adopts a three-stage gradient heating program, and the specific process is as follows: 120-140℃ is maintained for 20-40min, then heated to 160-170℃ and maintained for 50-70min, and then heated to 180-190℃ and maintained for 20-40min.

10. The process for the production of furfural and / or levulinic acid according to any one of claims 1 to 9, characterized in that, The heating reaction is carried out in an inert atmosphere. Preferably, the separation is carried out by in-situ adsorption.

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