Gamma-manganese oxide doped carbon layer coated Pt and Co catalyst as well as preparation method and application thereof
By wrapping Pt and Co catalysts with γ-manganese oxide doping carbon layer, the problems of poor conductivity and low efficiency of the catalyst during electrocatalytic disposal of lignin are solved, and efficient lignin conversion and single-ring product preparation are achieved.
Patent Information
- Application Number
- CN202510094509.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-21
- Publication Date
- 2025-05-23
AI Technical Summary
In the electrocatalytic disposal of lignin, existing catalysts have problems such as poor conductivity and low catalytic efficiency, which leads to difficulties in depolymerization of lignin.
The Pt, Co catalyst is encapsulated with a γ-manganese oxide doped carbon layer, and oxygen vacancies and crystal planes are provided through the γ-MnO2 support, combining the synergistic effects of Pt and Co, and limiting the migration and aggregation of metal active sites through the C frame.
The 100% conversion rate and 84% Faraday efficiency of the lignin model compound were achieved. After 20 cycle experiments, there was no conversion rate and Faraday efficiency attenuation, which significantly improved the catalytic depolymerization efficiency.
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of biomass resource utilization, and specifically relates to a gamma-manganese oxide doped carbon layer wrapped Pt, Co catalyst and a preparation method and application thereof. Background Art
[0002] Under the premise of fossil fuel depletion and increasing environmental pollution, the development of renewable biomass resources can significantly reduce pollutants and greenhouse gas emissions. Lignin is composed of phenylpropane groups connected by ether bonds and carbon-carbon bonds, and is considered to be the most abundant renewable aromatic biomass resource in nature. The efficient cracking of CO and CC bonds in the lignin structure by catalytic hydrodeoxygenation is an effective way to convert lignin derivatives into fuels and chemicals. Traditional thermochemical technology can destroy the internal unit connection bonds of lignin, but the harsh reaction conditions and energy consumption are not conducive to the large-scale promotion of lignin depolymerization technology. In addition, the uncontrollable thermal conversion effect will produce a series of by-products and cause lignin to be over-phenolized. Compared with the traditional reduction catalytic process of lignin derivatives, electrochemical catalytic reduction is driven by renewable energy and does not require hydrogen. It is an alternative catalytic strategy for lignin value-added. Therefore, electrochemical catalysis provides an ideal sustainable way to achieve efficient conversion of lignin into aromatic chemicals and crude fuel oil production. The commonly used catalytic method is to use heterogeneous catalysts to improve the conversion rate and product selectivity of lignin.
[0003] In recent years, metal oxidation catalysts have been frequently reported, and common metal catalysts include Ru, Pt, Pd, Rh, etc. By utilizing the synergistic effect of active metals and the catalyst surface, it shows high activity in breaking the chemical bonds of lignin at low temperatures. At present, researchers have done a lot of research on electrocatalytic biomass reduction reactions in order to obtain excellent catalysts with good activity and high stability. Compared with precious metals, transition metal oxides are more stable and have lower costs, and have received more and more attention. Among transition metal oxides, manganese oxides, as a catalyst with better activity among transition metal oxides, have been widely used in electrocatalysis. However, Mn oxide has poor conductivity and low catalytic efficiency of single manganese oxide, which makes the depolymerization of lignin very difficult. Summary of the invention
[0004] One technical problem solved by the present invention is to provide a method for preparing a γ-manganese oxide doped carbon layer wrapped Pt, Co catalyst. Another technical problem to be solved by the present invention is to provide a γ-manganese oxide doped carbon layer wrapped Pt, Co catalyst. Another technical problem to be solved by the present invention is to provide an application of a γ-manganese oxide doped carbon layer wrapped Pt, Co catalyst in the electrocatalytic depolymerization of lignin to prepare a monocyclic product. The use of a γ-manganese oxide carrier provides abundant oxygen vacancies, exposed crystal faces and crystal forms, and the introduced Pt nanoparticles rapidly activate hydrogen protons. The introduction of Co further increases the γ-MnO 2 The oxygen vacancy concentration is reduced, and the migration and agglomeration of metal active sites are limited by the wrapping of the C framework. It was used in lignin solution, and the results showed that the lignin model compound had a 100% conversion rate and 84% Faradaic efficiency. After 20 cycles, no attenuation of conversion rate and Faradaic efficiency was found.
[0005] Technical solution: In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:
[0006] A method for preparing a γ-manganese oxide doped carbon layer wrapped with a Pt, Co catalyst, wherein γ-MnO 2 , glucose, carbon black, chloroplatinic acid hexahydrate and / or cobalt nitrate hexahydrate are placed in a reaction container, deionized water is added, the temperature is raised and stirred for reaction, the mixture is dried, calcined under a nitrogen environment, and then calcined under a hydrogen environment to obtain a γ-manganese oxide doped carbon layer wrapped with a Pt, Co catalyst.
[0007] The preparation method of the γ-manganese oxide doped carbon layer wrapped with Pt, Co catalyst is to heat to 55-65°C, stir and react for 7-9 hours, and dry at 85-95°C; preferably, heat to 60°C, stir and react for 8 hours, and dry at 90°C.
[0008] The preparation method of the γ-manganese oxide doped carbon layer wrapped Pt, Co catalyst is calcined at 450-550 ° C for 1.5-2.5 h in a nitrogen environment, and then calcined at 450-550 ° C for 1.5-2.5 h in a hydrogen environment; preferably, calcined at 500 ° C for 2 h in a nitrogen environment, and then calcined at 500 ° C for 2 h in a hydrogen environment.
[0009] The preparation method of the γ-manganese oxide doped carbon layer wrapped Pt, Co catalyst, catalyst carrier γ-MnO 2 Preparation: (NH 4 ) 2 S 2 O 8 and MnN 2 O 6 ·4H 2O was mixed with distilled water, stirred magnetically to form a uniform solution, and then transferred into a hydrothermal synthesis reactor, which was placed in an oven at 90-140°C for 12 h; the product was collected, washed, filtered, dried at 80°C, and calcined at 300°C to remove the precursor, thereby obtaining the carrier γ-MnO 2 ; Preferably, the oven temperature is 90°C.
[0010] The preparation method of the γ-manganese oxide doped carbon layer wrapped Pt, Co catalyst, the mass content of platinum in the catalyst is 1%~5%, and the mass content of cobalt is 2%~5%; preferably, the mass content of platinum in the catalyst is 1% and the mass content of cobalt is 2%.
[0011] The gamma-manganese oxide doped carbon layer prepared by the above method wraps the Pt and Co catalysts.
[0012] The catalyst is used in the electrocatalytic depolymerization of lignin to prepare monocyclic products.
[0013] The application comprises wrapping Pt, Co catalyst with lignin and γ-manganese oxide doped carbon layer, placing the catalyst in an electrolytic cell, and then respectively adding phosphotungstic acid solution and phosphoric acid solution into two electrolytic cells; then heating and stirring the reaction, and treating the reaction after the reaction is completed to obtain a monocyclic product.
[0014] In the application, the reaction temperature is 80-90°C, the reaction current is 0.01-0.06 A, the stirring rate is 500-1000 r / min, and the reaction time is 15 min-2 h; preferably, the reaction temperature is 80°C, the reaction current is 0.02 A, the stirring rate is 560 r / min, and the reaction time is 90 min.
[0015] In the application, the mass ratio of lignin to catalyst is 1:1-5:1; the lignin is any one of benzyl phenyl ether, phenoxy acetate, 2-phenoxy-1-phenyl acetone or 2-phenoxy-1-phenylethanol; preferably, the mass ratio of lignin to catalyst is 5:1.
[0016] Beneficial effects: Compared with the prior art, the present invention has the following advantages:
[0017] (1) The present invention uses γ-manganese oxide as a carrier, commercially available manganese nitrate, cobalt nitrate, and chloroplatinic acid hexahydrate, and uses co-impregnation to prepare a solid acid catalyst by high-temperature calcination under an inert atmosphere. The prepared catalyst and lignin are placed in an electrolytic cell of an acidic system, a phosphotungstic acid solution is added to the cathode, and a phosphoric acid solution is added to the anode. The lignin catalytic depolymerization reaction is carried out at a certain temperature, and the purpose of directional generation of monocyclic products is achieved by controlling the reaction temperature, reaction pressure and reaction time.
[0018] (2) γ-MnO 2The carrier provides abundant oxygen vacancies, exposed crystal faces and crystal forms, providing an excellent carrier for the deposition of Pt particles. The introduced Pt nanoparticles activate hydrogen protons quickly, and the introduction of Co further increases the γ-MnO 2 The oxygen vacancy concentration was reduced, and the hydrogenation reduction of the substrate was promoted through the synergistic effect of Pt and Co metals. The migration and agglomeration of metal active sites were limited by the wrapping of the C framework, and the conversion rate of the lignin model compound was 100%, and the Faradaic efficiency was 84%. After 20 cycles, no attenuation of the conversion rate and Faradaic efficiency was found.
[0019] (3) The present invention controls the current density, induces efficient hydrogen proton dissociation of phosphotungstic acid, and generates electron-rich phosphotungstic acid (HPW3-) groups.
[0020] (4) The high-efficiency catalytic system proposed in the present invention provides a reference for designing an efficient lignin value-added method, avoiding the problems of equipment corrosion, high cost, complex products that are difficult to separate, environmental pollution, and waste of resources caused by traditional acid-base homogeneous catalysts. DETAILED DESCRIPTION
[0021] The present invention is further illustrated below in conjunction with specific examples. The examples are implemented based on the technical solutions of the present invention. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.
[0022] Example 1
[0023] γ-MnO was prepared by hydrothermal method. 2 4.5 g (NH 4 ) 2 S 2 O 8 and 3.8 g MnN 2 O 6 ·4H 2 O was mixed with 80 mL of distilled water and stirred magnetically for 30 min to form a uniform solution, and then transferred into a hydrothermal synthesis reactor (100 mL), which was placed in an oven at 90 °C for 12 h; the product was collected, washed, filtered, dried at 80 °C, and calcined at 300 °C to remove the precursor;
[0024] Pt and Co were doped by a simple impregnation method. 0.3 g γ-MnO 2, 0.05 g glucose, 0.1 g carbon black, 0.043 g chloroplatinic acid hexahydrate, and 0.058 g cobalt nitrate hexahydrate were put into a beaker, 40 mL deionized water was added, stirred at 60 ℃ for 8 h, dried at 90 ℃, calcined at 500 ℃ for 2 h in a nitrogen environment, and then calcined at 500 ℃ for 2 h in a hydrogen environment to obtain a γ-manganese oxide doped carbon layer wrapped with Pt (1%), Co (2%) catalyst, wherein Pt (1%) means that the percentage of Pt loading in the catalyst is 1% of the total mass of metal atoms and manganese oxide, and Co (2%) means that the percentage of Co loading in the catalyst is 2% of the total mass of metal atoms and manganese oxide.
[0025] 0.1 g of 2-phenoxy-1-phenylethanol and 0.02 g of catalyst were placed in an electrolytic cell, and 11 mL of phosphotungstic acid solution and 11 mL of phosphoric acid solution were added to the two electrolytic cells respectively. The temperature was then raised to 80 °C, the current was set to 0.02 A, and stirred at 560 r.
[0026] After 90 min of reaction, 5 mL of dichloromethane was added to the electrolytic cell. After dissolution, the solution was taken out with a disposable pipette and filtered once with an organic filter head (to separate the dichloromethane-insoluble products). Then, the dichloromethane-soluble products were collected to obtain the monocyclic products and qualitatively and quantitatively analyzed. According to calculations, the lignin conversion rate (GC standard sample, calculated by area normalization method) was 100%, the Faraday efficiency was 84%, and the monocyclic product yield reached 94%.
[0027] Example 2
[0028] 0.02 g of 2-phenoxy-1-phenylethanone and 0.02 g of the catalyst prepared in Example 1 were placed in an electrolytic cell, and 11 mL of phosphotungstic acid solution and 11 mL of phosphoric acid solution were added to the two electrolytic cells respectively. The temperature was then raised to 90 °C, the current was set to 0.02 A, and stirred at 560 r.
[0029] After 90 min of reaction, 5 mL of dichloromethane was added to the electrolytic cell. After dissolution, the solution was taken out with a disposable pipette and filtered once with an organic filter head (to separate the dichloromethane-insoluble products). The dichloromethane-soluble products were then collected, that is, the monocyclic products were obtained, and qualitative and quantitative analysis was performed on them. According to calculations, the lignin conversion rate was 92%, the Faraday efficiency was 15%, and the monocyclic product yield reached 78%.
[0030] Example 3
[0031] 0.02 g of benzyl phenyl ether and 0.02 g of the catalyst prepared in Example 1 were placed in an electrolytic cell, and 11 mL of phosphotungstic acid solution and 11 mL of phosphoric acid solution were added to the two electrolytic cells respectively. The temperature was then raised to 90 °C, the current was set to 0.02 A, and stirred at 560 r.
[0032] After 90 min of reaction, 5 mL of dichloromethane was added to the electrolytic cell. After dissolution, the solution was aspirated with a disposable pipette and filtered once with an organic filter head (to separate dichloromethane-insoluble products). Then, the dichloromethane-soluble products were collected to obtain monocyclic products, which were then qualitatively and quantitatively analyzed. According to calculations, the lignin conversion rate was 76%, the Faraday efficiency was 15%, and the monocyclic product yield reached 42%.
[0033] Example 4
[0034] γ-MnO was prepared by hydrothermal method. 2 4.5 g (NH 4 ) 2 S 2 O 8 and 3.8 g MnN 2 O 6 ·4H 2 O was mixed with 80 mL of distilled water and stirred magnetically for 30 min to form a uniform solution, and then transferred into a hydrothermal synthesis reactor (100 mL), which was placed in an oven at 90 °C for 12 h; the product was collected, washed, filtered, dried at 80 °C, and calcined at 300 °C to remove the precursor;
[0035] Pt was doped by a simple impregnation method. 0.3 g γ-MnO 2 , 0.05 g glucose, 0.1 g carbon black, and 0.215 g chloroplatinic acid hexahydrate were put into a beaker, 40 mL deionized water was added, stirred at 60 ℃ for 8 h, dried at 90 ℃, calcined at 500 ℃ for 2 h in a nitrogen environment, and then calcined at 500 ℃ for 2 h in a hydrogen environment to obtain a γ-manganese oxide doped carbon layer wrapped with Pt (5%) catalyst.
[0036] 0.02 g of benzyl phenyl ether and 0.02 g of catalyst were placed in an electrolytic cell, and 11 mL of phosphotungstic acid solution and 11 mL of phosphoric acid solution were added to the two electrolytic cells respectively. The temperature was then raised to 90 °C, the current was set to 0.02 A, and stirred at 560 r.
[0037] After 90 min of reaction, 5 mL of dichloromethane was added to the electrolytic cell. After dissolving, the solution was aspirated with a disposable pipette and filtered once with an organic filter head (to separate the dichloromethane-insoluble products). Then, the dichloromethane-soluble products were collected to obtain the monocyclic products, which were then qualitatively and quantitatively analyzed. According to calculations, the lignin conversion rate was 96%, the Faraday efficiency was 16%, and the monocyclic product yield reached 34%.
[0038] Example 5
[0039] γ-MnO was prepared by hydrothermal method. 2 4.5 g (NH 4 ) 2 S 2 O 8 and 3.8 g MnN 2 O 6 ·4H 2 O was mixed with 80 mL of distilled water and stirred magnetically for 30 min to form a uniform solution, and then transferred into a hydrothermal synthesis reactor (100 mL), which was placed in an oven at 90 °C for 12 h; the product was collected, washed, filtered, dried at 80 °C, and calcined at 300 °C to remove the precursor;
[0040] 0.3 g γ-MnO was doped with Co by a simple impregnation method. 2 , 0.05 g glucose, 0.1 g carbon black, and 0.29 g cobalt nitrate hexahydrate were put into a beaker, 40 mL deionized water was added, stirred at 60 ℃ for 8 h, dried at 90 ℃, calcined at 500 ℃ for 2 h in a nitrogen environment, and then calcined at 500 ℃ for 2 h in a hydrogen environment to obtain a γ-manganese oxide doped carbon layer wrapped Co (5%) catalyst.
[0041] 0.02 g of 2-phenoxy-1-phenylethanone and 0.02 g of catalyst were placed in the electrolytic cell, and 11 mL of phosphotungstic acid solution and 11 mL of phosphoric acid solution were added to the two electrolytic cells respectively. The temperature was then raised to 90 °C, the current was set to 0.02 A, and stirred at 560 r.
[0042] After 90 min of reaction, 5 mL of dichloromethane was added to the electrolytic cell. After dissolution, the solution was aspirated with a disposable pipette and filtered once with an organic filter head (to separate dichloromethane-insoluble products). The dichloromethane-soluble products were then collected, that is, the monocyclic products were obtained, and qualitative and quantitative analysis was performed on them. According to calculations, the lignin conversion rate was 90%, the Faraday efficiency was 15%, and the monocyclic product yield reached 43%.
[0043] Example 6
[0044] 0.1 g of 2-phenoxy-1-phenylethanol and 0.02 g of the catalyst prepared in Example 1 were placed in an electrolytic cell, and 11 mL of phosphotungstic acid solution and 11 mL of phosphoric acid solution were added to the two electrolytic cells respectively. The temperature was then raised to 80 °C, the current was set to 0.03 A, and stirred at 560 r.
[0045] After 90 min of reaction, 5 mL of dichloromethane was added to the electrolytic cell. After dissolving, the solution was aspirated with a disposable pipette and filtered once with an organic filter head (to separate dichloromethane-insoluble products). The dichloromethane-soluble products were then collected, that is, the monocyclic products were obtained, and qualitative and quantitative analysis was performed on them. According to calculations, the lignin conversion rate was 89%. The Faraday efficiency was 15%, and the yield of monocyclic products reached 78%.
[0046] Example 7
[0047] 0.1 g of 2-phenoxy-1-phenylethanol and 0.02 g of the catalyst prepared in Example 1 were placed in an electrolytic cell, and 11 mL of phosphotungstic acid solution and 11 mL of phosphoric acid solution were added to the two electrolytic cells respectively. The temperature was then raised to 80 °C, the current was set to 0.05 A, and stirred at 560 r.
[0048] After 90 min of reaction, 5 mL of dichloromethane was added to the electrolytic cell. After dissolving, the solution was aspirated with a disposable pipette and filtered once with an organic filter head (to separate the dichloromethane-insoluble products). The dichloromethane-soluble products were then collected, that is, the monocyclic products were obtained, and qualitative and quantitative analysis was performed on them. According to calculations, the lignin conversion rate was 92%. The Faraday efficiency was 15%, and the yield of the monocyclic products reached 82%.
[0049] Comparative Example 1
[0050] γ-MnO was prepared by hydrothermal method. 2 , 4.5 g (NH4) 2 S 2 O 8 and 3.8 g MnN 2 O 6 ·4H 2 O was mixed with 80 mL of distilled water and stirred magnetically for 30 min to form a uniform solution, and then transferred into a hydrothermal synthesis reactor (100 mL), which was placed in an oven at 90 °C for 12 h; the product was collected, washed, filtered, dried at 80 °C, and calcined at 300 °C to remove the precursor;
[0051] Pt and Co were doped by a simple impregnation method. 0.3 g γ-MnO 2, 0.05 g glucose, 0.043 g chloroplatinic acid hexahydrate, and 0.058 g cobalt nitrate hexahydrate were put into a beaker, 40 mL deionized water was added, stirred at 60 ℃ for 8 h, dried at 90 ℃, calcined at 500 ℃ for 2 h in a nitrogen environment, and then calcined at 500 ℃ for 2 h in a hydrogen environment to obtain γ-manganese oxide doped Pt (2%), Co (1%) catalyst.
[0052] 0.1 g of 2-phenoxy-1-phenylethanol and 0.02 g of catalyst were placed in an electrolytic cell, and 11 mL of phosphotungstic acid solution and 11 mL of phosphoric acid solution were added to the two electrolytic cells respectively. The temperature was then raised to 80 °C, the current was set to 0.02 A, and stirred at 560 r.
[0053] After 90 min of reaction, 5 mL of dichloromethane was added to the electrolytic cell. After dissolution, the solution was aspirated with a disposable pipette and filtered once with an organic filter head (to separate the dichloromethane-insoluble products). The dichloromethane-soluble products were then collected, that is, the monocyclic products were obtained, and qualitative and quantitative analysis was performed on them. According to calculations, the lignin conversion rate was 64%, the Faraday efficiency was 53%, and the monocyclic product yield was 64%.
[0054] Example 8
[0055] 0.1 g of 2-phenoxy-1-phenylethanol and 0.02 g of the catalyst prepared in Example 1 were placed in an electrolytic cell, and 11 mL of phosphotungstic acid solution and 11 mL of phosphoric acid solution were added to the two electrolytic cells respectively. The temperature was then raised to 80 °C, the current was set to 0.02 A, and stirred at 560 r.
[0056] After 90 min of reaction, 5 mL of dichloromethane was added to the electrolytic cell. After dissolution, the solution was taken out with a disposable pipette and filtered once with an organic filter head (to separate the dichloromethane-insoluble products). Then, the dichloromethane-soluble products were collected, that is, the monocyclic products were obtained and qualitatively and quantitatively analyzed. According to calculations, the lignin conversion rate was 100%, the Faraday efficiency was 84%, and the phenol yield was 45%.
[0057] The catalyst was filtered and dried for recovery, and 0.1 g of 2-phenoxy-1-phenylethanol and 0.02 g of the dried and recovered catalyst were placed in the electrolytic cell, and 11 mL of phosphotungstic acid solution and 11 mL of phosphoric acid solution were added to the two electrolytic cells respectively. The temperature was then raised to 80 °C, the current was set to 0.02 A, and stirred at 560 r.
[0058] After 90 min of reaction, 5 mL of dichloromethane was added to the electrolytic cell. After dissolution, the solution was taken out with a disposable pipette and filtered once with an organic filter head (to separate the dichloromethane-insoluble products). Then, the dichloromethane-soluble products were collected. This was repeated twenty times without any decrease in yield and Faraday efficiency.
[0059] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A method for preparing a Pt, Co catalyst doped with a γ-manganese oxide carbon layer, characterized in that: γ-MnO2, glucose, carbon black, chloroplatinic acid hexahydrate and / or cobalt nitrate hexahydrate are placed in a reaction container, deionized water is added, the temperature is raised and stirred for reaction, the reaction is dried, calcined under a nitrogen environment, and then calcined under a hydrogen environment to obtain a γ-manganese oxide doped carbon layer wrapped with Pt, Co catalyst.
2. The method for preparing the γ-manganese oxide doped carbon layer wrapped Pt, Co catalyst according to claim 1, characterized in that: Raise the temperature to 55~65 ℃ and stir for 7~9 h, then dry at 85~95 ℃.
3. The method for preparing the γ-manganese oxide doped carbon layer wrapped Pt, Co catalyst according to claim 1, characterized in that: Calcine at 450~550 ℃ for 1.5~2.5 h in a nitrogen environment, and then calcine at 450~550 ℃ for 1.5~2.5 h in a hydrogen environment.
4. The method for preparing the γ-manganese oxide doped carbon layer wrapped Pt, Co catalyst according to claim 1, characterized in that: Preparation of catalyst carrier γ-MnO2: (NH4)2S2O8 and MnN2O6·4H2O were mixed in distilled water, stirred magnetically to form a uniform solution, and then transferred into a hydrothermal synthesis reactor, which was placed in an oven at 90-140°C for 12 h. The product is collected, washed, filtered, dried, calcined, and the precursor is removed to obtain the carrier γ-MnO2.
5. The method for preparing the γ-manganese oxide doped carbon layer wrapped Pt, Co catalyst according to claim 1, characterized in that: The mass content of platinum in the catalyst is 1%~5% and the mass content of cobalt is 2%~5%.
6. A Pt, Co catalyst wrapped in a γ-manganese oxide doped carbon layer prepared by the method of any one of claims 1 to 5.
7. Use of the catalyst according to claim 6 in preparing monocyclic products by electrocatalytic depolymerization of lignin.
8. The use according to claim 7, characterized in that: The Pt and Co catalysts are wrapped with lignin and γ-manganese oxide doped carbon layers and placed in an electrolytic cell. Then, a phosphotungstic acid solution and a phosphoric acid solution are added to the two electrolytic cells respectively. The temperature is then raised and the reaction is stirred. After the reaction is completed, the monocyclic product is obtained through treatment.
9. The use according to claim 8, characterized in that: The reaction temperature is 80~90 ℃, the reaction current is 0.01~0.06 A, the stirring rate is 500~1000 r / min, and the reaction time is 15 min~2 h.
10. The use according to claim 1, characterized in that: The mass ratio of lignin to catalyst is 1:1-5:1; the lignin is any one of benzyl phenyl ether, phenoxy acetate, 2-phenoxy-1-phenyl acetone or 2-phenoxy-1-phenyl ethanol.