Method for preparing phenol from biomass raw material

Abstract

The invention discloses a method for preparing phenol by utilizing a biomass raw material, which comprises the following steps: 1) crushing biomass, adding the crushed biomass into a caustic alkali solution to carry out hemicellulose removal treatment, and carrying out solid-liquid separation to take a solid substance, so as to obtain hemicellulose-removed biomass; 2) adding the hemicellulose-removed biomass into an ethylene glycol-ferric chloride eutectic solvent for lignin extraction, then adding an acetone-water mixed solution, then carrying out solid-liquid separation, taking a liquid substance, adding water to precipitate the lignin, then carrying out solid-liquid separation, and taking a solid substance to obtain the lignin; and 3) pyrolyzing the lignin in a protective atmosphere to obtain lignin oil containing phenol. The method for preparing phenol from biomass raw materials has the advantages of simple operation, high phenol yield, high product purity, low energy consumption, safety, environmental protection and the like, and is suitable for large-scale industrial application.

Description

Technical Field

[0001] This invention relates to the field of biomass utilization technology, and specifically to a method for preparing phenol using biomass raw materials. Background Technology

[0002] Phenol is an important raw material for the production of bisphenol A, phenolic resins, bactericides, preservatives, and pharmaceuticals (such as aspirin), and is widely used in the chemical and medical fields. Currently, the main industrial method for producing phenol is the cumene process. This method involves alkylation of propylene and benzene under the catalysis of aluminum chloride to produce cumene. Cumene is then oxidized by oxygen or air to produce cumene hydroperoxide, which is then decomposed by sulfuric acid or acidic resin catalysis to finally obtain phenol and acetone. However, this method not only requires non-renewable benzene and propylene (both derived from fossil fuels), explosive hydrogen peroxide, and corrosive sulfuric acid as raw materials, but also generates a large amount of byproducts and waste during production, placing significant pressure on environmental protection. Furthermore, it suffers from a long process route, high energy consumption, and low phenol yield (only 5%), making it difficult to fully meet practical application requirements.

[0003] Studies have shown that lignin in biomass decomposes into phenol during pyrolysis, providing a new approach for phenol preparation. However, biomass has a complex composition, containing not only lignin but also cellulose, hemicellulose, and other components. This results in a low phenol content in the pyrolysis products, and the separation of phenol from the pyrolysis products is difficult and costly, severely limiting the practical application of this method for preparing phenol from biomass pyrolysis.

[0004] Therefore, it is of great significance to develop a method for preparing phenol from biomass raw materials that is simple to operate, has a high phenol yield, high product purity, low energy consumption, and is safe and environmentally friendly. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing phenol using biomass raw materials.

[0006] The technical solution adopted in this invention is:

[0007] A method for preparing phenol using biomass raw materials includes the following steps:

[0008] 1) The biomass is crushed and then added to a caustic alkali solution for de-hemicellulose treatment. The solid is then separated by solid-liquid separation to obtain de-hemicellulose biomass.

[0009] 2) The de-cellulosed biomass was added to an ethylene glycol-ferric chloride eutectic solvent for lignin extraction, then an acetone-water mixture was added, followed by solid-liquid separation. The liquid was then mixed with water to precipitate the lignin, and the solid was then separated to obtain lignin.

[0010] 3) Pyrolyze lignin under a protective atmosphere to obtain lignin oil containing phenol.

[0011] Preferably, the biomass in step 1) is at least one of poplar, eucalyptus, birch, oak, and elm.

[0012] Preferably, the biomass powder obtained by pulverizing the biomass in step 1) has a mesh size of 40 to 60 mesh.

[0013] Preferably, the mass ratio of biomass to caustic alkali solution in step 1) is 1:1 to 2.

[0014] Preferably, the mass fraction of the solute in the caustic alkali solution in step 1) is 8% to 12%.

[0015] Preferably, the solute in the caustic alkali solution in step 1) is at least one of sodium hydroxide and potassium hydroxide.

[0016] Preferably, the dehemicellulose treatment in step 1) is carried out at a temperature of 70℃~90℃ for a treatment time of 1h~5h.

[0017] Preferably, the solid-liquid separation method in step 1) is one of filtration or vacuum filtration.

[0018] Preferably, in step 2), the mass ratio of the de-hemicellulose biomass to the ethylene glycol-ferric chloride eutectic solvent is 1:10 to 30.

[0019] Preferably, in step 2), the molar ratio of ethylene glycol (EG) to ferric chloride (FeCl3) in the ethylene glycol-ferric chloride eutectic solvent is 1:0.1 to 0.7.

[0020] Preferably, the lignin extraction in step 2) is carried out at a temperature of 90℃~120℃ for 0.5h~3h.

[0021] Preferably, the acetone-water mixture in step 2) is composed of acetone and water in a volume ratio of 1:0.8 to 1.2.

[0022] Preferably, the amount of acetone-water mixture used in step 2) is 40 to 60 times the weight of the de-cellulosed biomass.

[0023] Preferably, the amount of water used in step 2) is 400 to 600 times the weight of the de-hemicellulose biomass.

[0024] Preferably, the solid-liquid separation method in step 2) is one of filtration or vacuum filtration.

[0025] Preferably, the protective atmosphere in step 3) is a nitrogen atmosphere or an argon atmosphere.

[0026] Preferably, the pyrolysis in step 3) is carried out at a temperature of 550℃ to 650℃ and the pyrolysis time is 60s to 120s.

[0027] The beneficial effects of this invention are: the method for preparing phenol using biomass raw materials has the advantages of simple operation, high phenol yield, high product purity, low energy consumption, safety and environmental protection, and is suitable for large-scale industrial application.

[0028] Specifically:

[0029] 1) This invention utilizes caustic alkali solution to treat biomass to remove hemicellulose and uses ethylene glycol-ferric chloride eutectic solvent to extract lignin, thereby achieving efficient separation of cellulose and hemicellulose from lignin in biomass, obtaining high-purity lignin, which can then be pyrolyzed to obtain lignin oil containing a high concentration of phenol.

[0030] 2) The lignin oil obtained by the method of the present invention can have a phenol content of up to about 40% by mass, and the yield of phenol is high.

[0031] 3) This invention uses a green ethylene glycol-ferric chloride eutectic solvent to replace traditional organic solvents for lignin extraction, with Fe at high temperature. 3+ Ions can promote the demethoxylation and reconstruction of aromatic rings, generating more H-type phenolic compounds, significantly improving the yield of phenol. Moreover, the ethylene glycol-ferric chloride eutectic solvent is non-toxic, easy to recycle, and safer and more environmentally friendly. Attached Figure Description

[0032] Figure 1 The images are FTIR diagrams of lignin from Examples 1 to 4.

[0033] Figure 2 The TG curves are for lignin in Examples 1-4.

[0034] Figure 3 The DTG curves are for the lignin in Examples 1-4.

[0035] Figure 4 The graph shows the elemental and high calorific value analysis results of lignin in Examples 1-4.

[0036] Figure 5 The images are SEM images of lignin from Examples 1 to 4.

[0037] Figure 6The Py-GCMS curves of lignin in Examples 1-4 are shown. Detailed Implementation

[0038] The present invention will be further explained and described below with reference to specific embodiments.

[0039] Example 1:

[0040] A method for preparing phenol using biomass raw materials, comprising the following steps:

[0041] 1) Pulverize poplar wood to 40-60 mesh, then add it to a 10% KOH solution with a mass ratio of poplar wood to KOH solution of 1:2. Heat the solution to 90℃ for 3 hours, filter to obtain the solid material, and obtain poplar wood with de-hemicellulose.

[0042] 2) Add the de-hemicellulose poplar wood to an ethylene glycol-ferric chloride eutectic solvent. The mass ratio of the de-hemicellulose poplar wood to the ethylene glycol-ferric chloride eutectic solvent is 1:20, and the molar ratio of ethylene glycol to ferric chloride in the ethylene glycol-ferric chloride eutectic solvent is 1:0.1. Then heat to 100℃ and treat for 2 hours. Then add an acetone-water mixture (the volume ratio of acetone to water is 1:1). The amount of acetone-water mixture used is 60 times the weight of the de-hemicellulose poplar wood. Filter and take the filtrate. Add water to precipitate the lignin. The amount of water used is 600 times the weight of the de-hemicellulose poplar wood. Filter and take the solid to obtain lignin.

[0043] 3) Pyrolyze lignin at 600°C for 90 seconds in a nitrogen atmosphere to obtain lignin oil (containing phenol).

[0044] Example 2:

[0045] A method for preparing phenol using biomass raw materials, comprising the following steps:

[0046] 1) Pulverize poplar wood to 40-60 mesh, then add it to a 10% KOH solution with a mass ratio of poplar wood to KOH solution of 1:2. Heat the solution to 90℃ for 3 hours, filter to obtain the solid material, and obtain poplar wood with de-hemicellulose.

[0047] 2) Add the de-hemicellulose poplar wood to an ethylene glycol-ferric chloride eutectic solvent. The mass ratio of the de-hemicellulose poplar wood to the ethylene glycol-ferric chloride eutectic solvent is 1:20, and the molar ratio of ethylene glycol to ferric chloride in the ethylene glycol-ferric chloride eutectic solvent is 1:0.3. Then heat to 100℃ and treat for 2 hours. Then add an acetone-water mixture (the volume ratio of acetone to water is 1:1). The amount of acetone-water mixture used is 60 times the weight of the de-hemicellulose poplar wood. Filter and take the filtrate. Add water to precipitate the lignin. The amount of water used is 600 times the weight of the de-hemicellulose poplar wood. Filter and take the solid to obtain lignin.

[0048] 3) Pyrolyze lignin at 600°C for 90 seconds in a nitrogen atmosphere to obtain lignin oil (containing phenol).

[0049] Example 3:

[0050] A method for preparing phenol using biomass raw materials, comprising the following steps:

[0051] 1) Pulverize poplar wood to 40-60 mesh, then add it to a 10% KOH solution with a mass ratio of poplar wood to KOH solution of 1:2. Heat the solution to 90℃ for 3 hours, filter to obtain the solid material, and obtain poplar wood with de-hemicellulose.

[0052] 2) Add the de-hemicellulose poplar wood to an ethylene glycol-ferric chloride eutectic solvent. The mass ratio of the de-hemicellulose poplar wood to the ethylene glycol-ferric chloride eutectic solvent is 1:20, and the molar ratio of ethylene glycol to ferric chloride in the ethylene glycol-ferric chloride eutectic solvent is 1:0.5. Then heat to 100℃ and treat for 2 hours. Then add an acetone-water mixture (the volume ratio of acetone to water is 1:1). The amount of acetone-water mixture used is 60 times the weight of the de-hemicellulose poplar wood. Filter and take the filtrate. Add water to precipitate the lignin. The amount of water used is 600 times the weight of the de-hemicellulose poplar wood. Filter and take the solid to obtain lignin.

[0053] 3) Pyrolyze lignin at 600°C for 90 seconds in a nitrogen atmosphere to obtain lignin oil (containing phenol).

[0054] Example 4:

[0055] A method for preparing phenol using biomass raw materials, comprising the following steps:

[0056] 1) Pulverize poplar wood to 40-60 mesh, then add it to a 10% KOH solution with a mass ratio of poplar wood to KOH solution of 1:2. Heat the solution to 90℃ for 3 hours, filter to obtain the solid material, and obtain poplar wood with de-hemicellulose.

[0057] 2) Add the de-hemicellulose poplar wood to an ethylene glycol-ferric chloride eutectic solvent. The mass ratio of the de-hemicellulose poplar wood to the ethylene glycol-ferric chloride eutectic solvent is 1:20, and the molar ratio of ethylene glycol to ferric chloride in the ethylene glycol-ferric chloride eutectic solvent is 1:0.7. Then heat to 100℃ and treat for 2 hours. Then add an acetone-water mixture (the volume ratio of acetone to water is 1:1). The amount of acetone-water mixture used is 60 times the weight of the de-hemicellulose poplar wood. Filter and take the filtrate. Add water to precipitate the lignin. The amount of water used is 600 times the weight of the de-hemicellulose poplar wood. Filter and take the solid to obtain lignin.

[0058] 3) Pyrolyze lignin at 600°C for 90 seconds in a nitrogen atmosphere to obtain lignin oil (containing phenol).

[0059] Comparative Example 1:

[0060] A method for preparing phenol using biomass raw materials, comprising the following steps:

[0061] 1) Pulverize poplar wood to 40-60 mesh, then add it to a 10% KOH solution with a mass ratio of poplar wood to KOH solution of 1:2. Heat the solution to 90℃ for 3 hours, filter to obtain the solid material, and obtain poplar wood with de-hemicellulose.

[0062] 2) Add the de-hemicellulose poplar wood to an ethylene glycol-ferric chloride eutectic solvent. The mass ratio of the de-hemicellulose poplar wood to the ethylene glycol-ferric chloride eutectic solvent is 1:20, and the molar ratio of ethylene glycol to ferric chloride in the ethylene glycol-ferric chloride eutectic solvent is 1:0.05. Then heat to 100℃ and treat for 2 hours. Then add an acetone-water mixture (the volume ratio of acetone to water is 1:1). The amount of acetone-water mixture used is 60 times the weight of the de-hemicellulose poplar wood. Filter and take the filtrate. Add water to precipitate the lignin. The amount of water used is 600 times the weight of the de-hemicellulose poplar wood. Filter and take the solid to obtain lignin.

[0063] 3) Pyrolyze lignin at 600°C for 90 seconds in a nitrogen atmosphere to obtain lignin oil (containing phenol).

[0064] Comparative Example 2:

[0065] A method for preparing phenol using biomass raw materials, comprising the following steps:

[0066] 1) Pulverize poplar wood to 40-60 mesh, then add it to a 10% KOH solution with a mass ratio of poplar wood to KOH solution of 1:2. Heat the solution to 90℃ for 3 hours, filter to obtain the solid material, and obtain poplar wood with de-hemicellulose.

[0067] 2) Add the de-hemicellulose poplar wood to an ethylene glycol-ferric chloride eutectic solvent. The mass ratio of the de-hemicellulose poplar wood to the ethylene glycol-ferric chloride eutectic solvent is 1:20, and the molar ratio of ethylene glycol to ferric chloride in the ethylene glycol-ferric chloride eutectic solvent is 1:1. Then heat to 100℃ and treat for 2 hours. Then add an acetone-water mixture (the volume ratio of acetone to water is 1:1). The amount of acetone-water mixture used is 60 times the weight of the de-hemicellulose poplar wood. Filter and take the filtrate. Add water to precipitate the lignin. The amount of water used is 600 times the weight of the de-hemicellulose poplar wood. Filter and take the solid to obtain lignin.

[0068] 3) Pyrolyze lignin at 600°C for 90 seconds in a nitrogen atmosphere to obtain lignin oil (containing phenol).

[0069] Comparative Example 3:

[0070] A method for preparing phenol using biomass raw materials, comprising the following steps:

[0071] 1) Pulverize poplar wood to 40-60 mesh, then add it to a 10% KOH solution with a mass ratio of poplar wood to KOH solution of 1:2. Heat the solution to 90℃ for 3 hours, filter to obtain the solid material, and obtain poplar wood with de-hemicellulose.

[0072] 2) Add the de-hemicellulose poplar to an ethylene glycol-ferric chloride eutectic solvent. The mass ratio of the de-hemicellulose poplar to the ethylene glycol-ferric chloride eutectic solvent is 1:20, and the molar ratio of ethylene glycol to ferric chloride in the ethylene glycol-ferric chloride eutectic solvent is 1:0.1. Then heat to 140℃ for 2 hours. Then add an acetone-water mixture (the volume ratio of acetone to water is 1:1). The amount of acetone-water mixture used is 60 times the weight of the de-hemicellulose poplar. Filter and add water to the filtrate to precipitate lignin. The amount of water used is 600 times the weight of the de-hemicellulose poplar. Filter and collect the solid to obtain lignin.

[0073] 3) Pyrolyze lignin at 600°C for 90 seconds in a nitrogen atmosphere to obtain lignin oil (containing phenol).

[0074] Comparative Example 4:

[0075] A method for preparing phenol using biomass raw materials, comprising the following steps:

[0076] 1) Pulverize poplar wood to 40-60 mesh, then add it to a 10% KOH solution with a mass ratio of poplar wood to KOH solution of 1:2. Heat the solution to 90℃ for 3 hours, filter to obtain the solid material, and obtain poplar wood with de-hemicellulose.

[0077] 2) Add the de-hemicellulose poplar wood to an ethylene glycol-ferric chloride eutectic solvent. The mass ratio of the de-hemicellulose poplar wood to the ethylene glycol-ferric chloride eutectic solvent is 1:20, and the molar ratio of ethylene glycol to ferric chloride in the ethylene glycol-ferric chloride eutectic solvent is 1:0.1. Then heat to 100℃ and treat for 4 hours. Then add an acetone-water mixture (the volume ratio of acetone to water is 1:1). The amount of acetone-water mixture used is 60 times the weight of the de-hemicellulose poplar wood. Filter and take the filtrate. Add water to precipitate the lignin. The amount of water used is 600 times the weight of the de-hemicellulose poplar wood. Filter and take the solid to obtain lignin.

[0078] 3) Pyrolyze lignin at 600°C for 90 seconds in a nitrogen atmosphere to obtain lignin oil (containing phenol).

[0079] Comparative Example 5:

[0080] A method for preparing phenol using biomass raw materials, comprising the following steps:

[0081] 1) Pulverize poplar wood to 40-60 mesh, then add it to a 10% KOH solution with a mass ratio of poplar wood to KOH solution of 1:2. Heat the solution to 90℃ for 3 hours, filter to obtain the solid material, and obtain poplar wood with de-hemicellulose.

[0082] 2) Add the de-hemicellulose poplar wood to an ethylene glycol-aluminum chloride eutectic solvent. The mass ratio of the de-hemicellulose poplar wood to the ethylene glycol-aluminum chloride eutectic solvent is 1:20, and the molar ratio of ethylene glycol to aluminum chloride in the ethylene glycol-aluminum chloride eutectic solvent is 1:0.1. Then heat to 100℃ and treat for 2 hours. Then add an acetone-water mixture (the volume ratio of acetone to water is 1:1). The amount of acetone-water mixture used is 60 times the weight of the de-hemicellulose poplar wood. Filter and take the filtrate. Add water to precipitate the lignin. The amount of water used is 600 times the weight of the de-hemicellulose poplar wood. Filter and take the solid to obtain lignin.

[0083] 3) Pyrolyze lignin at 600°C for 90 seconds in a nitrogen atmosphere to obtain lignin oil (containing phenol).

[0084] Comparative Example 6:

[0085] A method for preparing phenol using biomass raw materials, comprising the following steps:

[0086] 1) Pulverize poplar wood to 40-60 mesh, then add it to a 10% KOH solution with a mass ratio of poplar wood to KOH solution of 1:2. Heat the solution to 90℃ for 3 hours, filter to obtain the solid material, and obtain poplar wood with de-hemicellulose.

[0087] 2) Add the de-hemicellulose poplar wood to an ethylene glycol-copper chloride eutectic solvent. The mass ratio of the de-hemicellulose poplar wood to the ethylene glycol-copper chloride eutectic solvent is 1:20, and the molar ratio of ethylene glycol to copper chloride in the ethylene glycol-copper chloride eutectic solvent is 1:0.1. Then heat to 100℃ and treat for 2 hours. Then add an acetone-water mixture (the volume ratio of acetone to water is 1:1). The amount of acetone-water mixture used is 60 times the weight of the de-hemicellulose poplar wood. Filter and take the filtrate. Add water to precipitate the lignin. The amount of water used is 600 times the weight of the de-hemicellulose poplar wood. Filter and take the solid to obtain lignin.

[0088] 3) Pyrolyze lignin at 600°C for 90 seconds in a nitrogen atmosphere to obtain lignin oil (containing phenol).

[0089] Comparative Example 7:

[0090] A method for preparing phenol using biomass raw materials, comprising the following steps:

[0091] 1) Pulverize poplar wood to 40-60 mesh, then add it to distilled water at a mass ratio of 1:15. Place the mixture in a reaction vessel and heat it to 120°C for 0.5 hours. Filter the solids to obtain de-hemicellulose poplar wood.

[0092] 2) Add the de-hemicellulose poplar wood to an ethylene glycol-ferric chloride eutectic solvent. The mass ratio of the de-hemicellulose poplar wood to the ethylene glycol-ferric chloride eutectic solvent is 1:20, and the molar ratio of ethylene glycol to ferric chloride in the ethylene glycol-ferric chloride eutectic solvent is 1:0.1. Then heat to 100℃ and treat for 2 hours. Then add an acetone-water mixture (the volume ratio of acetone to water is 1:1). The amount of acetone-water mixture used is 60 times the weight of the de-hemicellulose poplar wood. Filter and take the filtrate. Add water to precipitate the lignin. The amount of water used is 600 times the weight of the de-hemicellulose poplar wood. Filter and take the solid to obtain lignin.

[0093] 3) Pyrolyze lignin at 600°C for 90 seconds in a nitrogen atmosphere to obtain lignin oil (containing phenol).

[0094] Comparative Example 8:

[0095] A method for preparing phenol using biomass raw materials, comprising the following steps:

[0096] 1) Pulverize poplar wood to 40-60 mesh, then add it to distilled water at a mass ratio of 1:15. Place the mixture in a reaction vessel and heat it to 140℃ for 0.5 hours. Filter the solids to obtain de-hemicellulose poplar wood.

[0097] 2) Add the de-hemicellulose poplar wood to an ethylene glycol-ferric chloride eutectic solvent. The mass ratio of the de-hemicellulose poplar wood to the ethylene glycol-ferric chloride eutectic solvent is 1:20, and the molar ratio of ethylene glycol to ferric chloride in the ethylene glycol-ferric chloride eutectic solvent is 1:0.1. Then heat to 100℃ and treat for 2 hours. Then add an acetone-water mixture (the volume ratio of acetone to water is 1:1). The amount of acetone-water mixture used is 60 times the weight of the de-hemicellulose poplar wood. Filter and take the filtrate. Add water to precipitate the lignin. The amount of water used is 600 times the weight of the de-hemicellulose poplar wood. Filter and take the solid to obtain lignin.

[0098] 3) Pyrolyze lignin at 600°C for 90 seconds in a nitrogen atmosphere to obtain lignin oil (containing phenol).

[0099] Performance testing:

[0100] 1) Fourier transform infrared (FTIR) spectra of lignin in Examples 1-4 are shown below. Figure 1As shown, the thermogravimetric (TG) curve is as follows: Figure 2 As shown, the thermogravimetric (DTG) curve for micro-businesses is as follows: Figure 3 As shown, the elemental and high calorific value analysis results are as follows: Figure 4 As shown, the scanning electron microscope (SEM) image is as follows: Figure 5 As shown, the pyrolysis gas chromatography-mass spectrometry (Py-GCMS) curve is as follows: Figure 6 As shown.

[0101] Depend on Figure 1 It can be seen that the main chain structure of lignin remained basically stable during the lignin extraction process in Examples 1 to 4, indicating that the mechanism of action of the eutectic solvent (DES) mainly depends on the physical exfoliation process rather than strong chemical reconstruction.

[0102] Depend on Figure 2 It can be seen that the lignin in Examples 1 to 4 has high activity and good pyrolysis performance.

[0103] Depend on Figure 3 It can be seen that the lignin in Examples 1 to 4 decomposes rapidly, has strong thermal stability, and produces few pyrolysis byproducts.

[0104] Depend on Figure 4 It can be seen that the lignin in Examples 1 to 4 has a high carbon content, low oxygen content, and high calorific value, making it suitable as a precursor for biofuels or chemicals.

[0105] Depend on Figure 5 It can be seen that the lignin in Examples 1 to 4 did not have excessive agglomeration, had a low degree of polymerization, good pyrolysis adaptability, and small and uniform particles, which is beneficial to downstream reactions.

[0106] Depend on Figure 6 It can be seen that the lignin in Examples 1 to 4 is rich in phenolic products after thermal decomposition, and has good potential for thermal conversion.

[0107] In summary, the lignin in Examples 1-4 exhibits excellent performance in terms of structural integrity, thermal stability, and calorific value, making it suitable for further utilization as a high-value biomass resource.

[0108] 2) The delignination rate, lignin oil yield, and phenol content of the lignin oil in Examples 1-4 and Comparative Examples 1-8 are shown in the table below:

[0109] Table 1. Delignination rate, lignin oil yield, and phenol content of lignin oil

[0110]

[0111] Note:

[0112] Delignin removal rate: Measured by spectroscopic method.

[0113] The formula for calculating the deligninization rate is: Deligninization rate (%) = (Lignin content of dehemicellulose biomass - Lignin content of dehemicellulose biomass after lignin extraction) / Lignin content of dehemicellulose biomass × 100%.

[0114] The formula for calculating lignin oil yield is: Lignonin oil yield (%) = weight of lignin oil / weight of lignin × 100%.

[0115] Phenol content of lignin oil: determined by thermal pyrolysis gas chromatography-mass spectrometry (Py-GCMS).

[0116] As shown in Table 1:

[0117] a) The high delignination rate, lignin oil yield, and phenol content of lignin oil in Examples 1-4 demonstrate that the method of preparing phenol using biomass raw materials in this invention does indeed have advantages such as simple operation, high phenol yield, high product purity, low energy consumption, and safety and environmental protection.

[0118] b) Compared with Comparative Examples 1-8, Examples 1-4 showed significantly higher deligninization rate, lignin oil yield, and phenol content of lignin oil, indicating that the temperature and time of hemicellulose removal treatment, the raw material composition and ratio of the eutectic solvent, and the temperature and time of lignin extraction are crucial.

[0119] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing phenol using biomass raw materials, characterized in that, Includes the following steps: 1) The biomass is crushed and then added to a caustic alkali solution for de-hemicellulose treatment. The solid is then separated by solid-liquid separation to obtain de-hemicellulose biomass. 2) The de-cellulosed biomass was added to an ethylene glycol-ferric chloride eutectic solvent for lignin extraction, then an acetone-water mixture was added, followed by solid-liquid separation. The liquid was then mixed with water to precipitate the lignin, and the solid was then separated to obtain lignin. 3) Pyrolyze lignin under a protective atmosphere to obtain lignin oil containing phenol.

2. The method for preparing phenol using biomass raw materials according to claim 1, characterized in that: Step 1) The biomass is at least one of poplar, eucalyptus, birch, oak, and elm.

3. The method for preparing phenol from biomass raw materials according to claim 1 or 2, characterized in that: The mass ratio of biomass to caustic alkali solution in step 1) is 1:1 to 2; the mass fraction of solute in the caustic alkali solution in step 1) is 8% to 12%.

4. The method for preparing phenol from biomass raw materials according to claim 1 or 2, characterized in that: The solute in the caustic alkali solution in step 1) is at least one of sodium hydroxide and potassium hydroxide.

5. The method for preparing phenol from biomass raw materials according to claim 1 or 2, characterized in that: The de-hemicellulose treatment in step 1) is carried out at a temperature of 70℃~90℃ for 1h~5h.

6. The method for preparing phenol from biomass raw materials according to claim 1, characterized in that: In step 2), the mass ratio of the de-hemicellulose biomass to the ethylene glycol-ferric chloride eutectic solvent is 1:10-30.

7. The method for preparing phenol from biomass raw materials according to claim 1 or 6, characterized in that: In step 2), the molar ratio of ethylene glycol to ferric chloride in the ethylene glycol-ferric chloride eutectic solvent is 1:0.1 to 0.

7.

8. The method for preparing phenol from biomass raw materials according to claim 1 or 6, characterized in that: Step 2) The lignin extraction is carried out at a temperature of 90℃~120℃ for 0.5h~3h.

9. The method for preparing phenol from biomass raw materials according to claim 1 or 6, characterized in that: The amount of acetone-water mixture used in step 2) is 40 to 60 times the weight of the de-cellulosed biomass; the acetone-water mixture used in step 2) is composed of acetone and water in a volume ratio of 1:0.8 to 1.2; the amount of water used in step 2) is 400 to 600 times the weight of the de-cellulosed biomass.

10. The method for preparing phenol from biomass raw materials according to any one of claims 1, 2 and 6, characterized in that: Step 3) The pyrolysis is carried out at a temperature of 550℃~650℃ for a time of 60s~120s.

Images