CN113387766B

CN113387766B - Method for preparing pure benzene by catalytic conversion of lignin by using metal-supported catalyst

Info

Publication number: CN113387766B
Application number: CN202110804819.3A
Authority: CN
Inventors: 孟庆磊; 严江; 吴睿智; 韩布兴
Original assignee: Institute of Chemistry CAS
Current assignee: Institute of Chemistry CAS
Priority date: 2021-07-16
Filing date: 2021-07-16
Publication date: 2022-04-12
Anticipated expiration: 2041-07-16
Also published as: CN113387766A

Abstract

The invention discloses a method for preparing pure benzene by catalytic conversion of lignin by using a metal-supported catalyst. It comprises the following steps: the lignin is prepared by taking a metal ruthenium-tungsten loaded high-silicon molecular sieve as a catalyst and carrying out catalytic conversion reaction. The method provided by the invention adopts the metal supported catalyst for catalysis, the product is mainly benzene, the catalyst system is simple, green and environment-friendly, the lignin is cheap and easy to obtain, and the possibility is provided for large-scale catalytic conversion and utilization of the lignin.

Description

Method for preparing pure benzene by catalytic conversion of lignin by using metal-supported catalyst

Technical Field

The invention relates to a method for preparing pure benzene by catalytic conversion of lignin by a metal-loaded catalyst, belonging to the field of preparation of high-added-value chemicals by catalytic conversion of biomass.

Background

In modern industry, pure benzene is an important primary chemical raw material, is used for producing important bulk chemicals such as styrene, caprolactam, phenol, aniline, adipic acid, alkylbenzene, maleic anhydride and the like, can also be used as a solvent and a fuel, and has wide application in the fields of chemical fibers, plastics, medicines, pesticides, spices, dyes, coatings and the like. At present, pure benzene mainly comes from petroleum refining industry and coal coking industry, benzene obtained by separating byproducts of ethylene cracking or toluene disproportionation process or products of catalytic reforming is called petroleum benzene, and benzene obtained by separating byproducts generated in coal coking process is called hydrogenated benzene.

Lignin is a natural polymer formed by connecting three basic structural units of p-hydroxyphenyl propane (H) structure, guaiacyl propane (G) structure and syringyl propane (S structure) through C-O bond and C-C bond, exists in plants in nature in a large amount, and is a renewable aromatic carbon resource with great application potential.

Disclosure of Invention

The invention aims to provide a method for preparing pure benzene by catalytically converting lignin by using a metal-supported catalyst.

The method takes metal ruthenium tungsten loaded on a high-silicon molecular sieve as a catalyst to catalyze and convert lignin into pure benzene. By analyzing the structure of the lignin, C-O bonds and C-C bonds connected with benzene rings in the lignin structure are selectively broken, and pure benzene is obtained from the lignin. Therefore, pure benzene with high selectivity from lignin has important practical value.

The invention provides a method for preparing pure benzene by catalytic conversion of lignin by using a metal-supported catalyst, which comprises the following steps: the lignin is prepared by taking a metal ruthenium-tungsten loaded high-silicon molecular sieve as a catalyst and carrying out catalytic conversion reaction.

In the method, in the ruthenium-tungsten-loaded high-silicon molecular sieve, the ruthenium-tungsten is an alloy or a mixture of ruthenium and tungsten, and the high-silicon molecular sieve is an HY molecular sieve and/or a ZSM-5 molecular sieve.

In the invention, the metal ruthenium-tungsten loaded high-silicon molecular sieve is prepared by a common method known in the field; the method specifically adopts common wet impregnation, and comprises the following steps: dissolving a metal precursor (the precursor of the metal ruthenium tungsten) in water, dripping the solution into a suspension of a carrier (the high-silicon molecular sieve) under a stirring state, removing water, drying, and reducing under a reducing atmosphere to obtain the metal ruthenium tungsten-loaded high-silicon molecular sieve.

In the method, the atomic ratio of Si to Al of the HY molecular sieve can be specifically 10-50; more specifically, 15 to 40; further more specifically 15, 30 or 40;

the atomic ratio of Si to Al of the ZSM-5 molecular sieve can be specifically 100-500; specifically 235.

In the method, in the metallic ruthenium-tungsten loaded high-silicon molecular sieve, the loading amount of ruthenium is 0.1-20% by mass, specifically 3%, 5% and 8% by mass of the high-silicon molecular sieve, and the loading amount of tungsten is 1-50% by mass, specifically 20%, 25% and 30% by mass of the high-silicon molecular sieve.

In the above method, the mass of the catalyst may be 10% to 200%, specifically 60% to 150%, of the mass of the lignin.

In the above method, the conditions of the catalytic conversion reaction are as follows: the pressure can be 0.1MPa to 10 MPa; the temperature can be 100-350 ℃; the time can be 0.5h to 24 h;

the specific conditions can be 0.5MPa, 240 ℃, 250 ℃, 260 ℃ or 240-260 ℃ and the time is 12 h.

In the above method, the catalytic conversion reaction is carried out in an air atmosphere, an inert atmosphere and/or a hydrogen atmosphere; specifically, the atmosphere can be inert atmosphere, mixed atmosphere of inert atmosphere and hydrogen atmosphere or hydrogen atmosphere;

in the above method, the inert atmosphere is argon and/or nitrogen.

In the above method, the catalytic conversion reaction is carried out under the condition of introducing hydrogen: the amount of hydrogen introduced into each gram of lignin is 0-10 mmol.

In the above method, the catalytic conversion reaction is carried out under stirring;

the stirring speed can be 400 rpm-1000 rpm specifically; and more specifically may be 800 rpm.

In the above method, the catalytic conversion reaction is carried out in a solvent;

the solvent is specifically water.

In the method, the mass ratio of the water to the lignin can be 5-50: 1; specifically 10-20: 1; and more specifically may be 13: 1.

In the method, the raw material for extracting the lignin is at least one selected from poplar, pine, willow, cedar, elm, toona, peach, fruit tree, fir, eucalyptus and moso bamboo.

In the above method, the method for extracting lignin comprises the following steps: and hydrolyzing the wood flour of the raw material with high-temperature water or acid hydrolysis in an organic solvent and water to obtain the lignin.

In the above method, the organic solvent is at least one of acetone, butanone, ethanol, isopropanol and dioxane;

the volume ratio of the organic solvent to the water can be 1-9: 1; specifically, the ratio can be 2-6: 1; more specifically 2-3: 1, and in specific embodiments 4.9:2.1, 2.5:1, or 2.3-2.5: 1;

the mass ratio of the total volume of the organic solvent and the water to the wood powder can be 5-15 mL:1 g; specifically, the amount of the active ingredients is 6-12 ml:1 g; more specifically, the amount of the surfactant is 6-10 ml:1g, and in a specific embodiment, the amount of the surfactant is 10ml:1 g.

In the above method, the acid in the acid hydrolysis is hydrochloric acid; the mass ratio of the hydrochloric acid to the wood powder can be 0-1: 1; specifically, the ratio of the total amount of the components can be 0.01-0.50: 1; more specifically, the ratio may be 0.01 to 0.1:1, or 0.05: 1.

In the above method, the high-temperature water hydrolysis or acid hydrolysis is performed under stirring conditions; specifically, the stirring speed may be 400rpm to 1600rpm, specifically 600rpm, 800rpm, or 600rpm to 800 rpm.

In the method, the temperature of the high-temperature water hydrolysis or acid hydrolysis can be 80-200 ℃; specifically 90-180 deg.C, more specifically 100 deg.C, 110 deg.C, 160 deg.C or 110-160 deg.C; the time can be 0.5h to 6h, specifically can be 1h to 2h, and more specifically can be 1 h.

In the above method, the high-temperature water hydrolysis or acid hydrolysis is carried out in an inert atmosphere; the inert gas atmosphere is specifically nitrogen and/or argon, and the pressure of the inert gas can be 0.5MPa to 1MPa, specifically 0.5MPa and 0.5MPa to 1 MPa.

The invention has the following advantages:

1. the method provided by the invention adopts a metal-loaded catalyst for catalysis, and the product is mainly benzene;

2. the reaction of the invention can be carried out in air atmosphere, and is more beneficial to the reaction under the condition that oxygen in an inert atmosphere removing system or a very small amount of hydrogen participates in the reaction.

3. The catalyst system is simple, green and environment-friendly, and the lignin is cheap and easy to obtain, so that the possibility is provided for large-scale catalytic conversion and utilization of the lignin.

Drawings

FIG. 1 shows the two-dimensional NMR spectrum and the corresponding structure of the extracted lignin from pine wood as organic solvent in example 1 of the present invention.

FIG. 2 is a gas chromatogram of the product of example 1 according to the present invention.

FIG. 3 is a mass spectrum of the product of example 1 of the present invention.

FIG. 4 shows the two-dimensional NMR spectrum and the corresponding structure of the extracted Ailanthus altissima organic solvent lignin in example 2 of the present invention.

Fig. 5 shows a two-dimensional nuclear magnetic resonance spectrum and a corresponding structure of the poplar organosolv lignin separated and extracted in example 3 of the present invention.

FIG. 6 shows the two-dimensional NMR spectrum and the corresponding structure of the lignin extracted and separated from willow organic solvent in example 4 of the present invention.

Fig. 7 shows the two-dimensional nmr spectrum and the corresponding structure of the eucalyptus organosolv lignin isolated and extracted in example 5 of the present invention.

Detailed Description

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

The ZSM-5 and HY molecular sieves in the examples below were obtained from Alfa Aesar or Tianjin Minn catalyst Ltd.

Example 1

(1) Preparation of pine wood organic solvent lignin raw material

70g of pine wood powder, 490mL of acetone and 210mL of deionized water are added into a 1000mL acid and alkali resistant high pressure reaction kettle, and oxygen in the kettle is replaced by nitrogen. The nitrogen in the kettle was pressurized to 0.5MPa, the reaction kettle was heated to 160 ℃ with stirring at 600rpm, and the temperature was maintained for 1 h. Then cooling to room temperature, filtering, and washing filter residue by using 90% by volume of acetone aqueous solution. Mixing filtrates, concentrating, slowly adding the concentrated solution dropwise into 2000ml of deionized water, filtering the precipitate, freeze drying to remove water, dissolving in 100ml of acetone/methanol (volume ratio of 9:1), slowly adding dropwise into 1000ml of anhydrous ether, filtering the precipitate, and vacuum drying at 60 deg.C to obtain pine wood organic solvent lignin. As can be seen from the two-dimensional nuclear magnetic spectrum (figure 1) of the pine wood organosolv lignin extracted and separated by the method, a large amount of alpha-C hydroxyl, gamma-C hydroxyl and beta-O-4 ether bond structures (A) exist in the pine wood organosolv lignin, and a structural unit B, C for polycondensation reaction also exists; H. g, S all three building blocks are present in the lignin.

(2) HY loaded ruthenium-tungsten alloy₃₀Molecular sieve catalyst (RuW/HY)₃₀) Preparation of

RuW/HY₃₀The catalyst is prepared by a wet impregnation method. Before impregnation, HY₃₀The molecular sieve (the atomic ratio of Si and Al of HY molecular sieve is 30, the same below) is calcined at 550 deg.C for 4 h. 1.25g of ammonium metatungstate and 0.40g of ruthenium trichloride were dissolved in 15mL of deionized water, and a precursor solution containing ammonium metatungstate and ruthenium trichloride was dropwise added to a suspension containing 2g of HY₃₀Molecular sieves in 70mL of deionized water. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 1 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in an/Ar atmosphere, and the formed passivation layer can prevent the catalyst from being strongly oxidized when exposed to air. The passivated catalyst was maintained under an inert atmosphere prior to characterization and use.

(3) Reaction for preparing pure benzene by lignin conversion

Adding 0.5g pine wood organic solvent lignin, 0.5g RuW/HY₃₀Catalyst (3.5 wt% Ru,20 wt% W), 6.5mL deionized water was added to a 20mL Teflon lined reactor, the autoclave was sealed, the air in the reactor was replaced with argon and argon was added to 0.5MPa, the stirring speed was 800rpm, the temperature was raised to 240 ℃ and maintained for 12 h. After the reaction is finished, the reaction mixture is rapidly cooled to room temperature (25 ℃), the reaction mixture is subjected to centrifugal separation after air bleeding, liquid is extracted by ethyl acetate and then is analyzed by a gas chromatograph-mass spectrometer and a gas chromatograph, and the ratio of the quality of the pure benzene to the quality of the lignin is the benzene yield.

(4) After the reaction, a gas chromatogram of the product is shown in FIG. 2; FIG. 3 shows the mass spectrum of the product, and GC-MS and GC analysis in FIGS. 2 and 3 show that the product is mainly pure benzene with a yield of 18.8 wt%.

Example 2

(1) Preparing raw material of toona sinensis organic solvent lignin

70g of Chinese toon wood powder, 490mL of acetone and 210mL of deionized water are added into a 1000mL acid and alkali resistant high-pressure reaction kettle, and nitrogen is used for replacing oxygen in the kettle. The nitrogen in the kettle was pressurized to 0.5MPa, the reaction kettle was heated to 160 ℃ with stirring at 600rpm, and the temperature was maintained for 1 h. Then cooling to room temperature, filtering, and washing filter residue by using 90% by volume of acetone aqueous solution. Mixing filtrates, concentrating, slowly adding the concentrated solution dropwise into 2000ml of deionized water, filtering the precipitate, freeze-drying to remove water, dissolving in 100ml of acetone/methanol (volume ratio of 9:1), slowly adding dropwise into 1000ml of anhydrous ether, filtering the precipitate, and finally vacuum-drying at 60 deg.C to obtain the toona sinensis organic solvent lignin. As can be seen from the two-dimensional nuclear magnetic spectrum (figure 4) of the ailanthus altissima organic solvent lignin extracted and separated by the method, a large amount of alpha-C hydroxyl, gamma-C hydroxyl and beta-O-4 ether bond structures (A) exist in the ailanthus altissima organic solvent lignin, and a structural unit B, C which is subjected to polycondensation reaction also exists; G. s two building blocks are present in the lignin.

RuW/HY₃₀The catalyst is prepared by a wet impregnation method. Before impregnation, HY₃₀The molecular sieve is burned for 4h at 550 ℃. 1.25g of ammonium metatungstate and 0.40g of ruthenium trichloride were dissolved in 15mL of deionized water, and a precursor solution containing ammonium metatungstate and ruthenium trichloride was dropwise added to a suspension containing 2g of HY₃₀Molecular sieves in 70mL of deionized water. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 1 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in/Ar atmosphere, and forming a passivation layer capable of preventingThe catalyst is strongly oxidized when exposed to air. The passivated catalyst was maintained under an inert atmosphere prior to characterization and use.

(3) Reaction for preparing pure benzene by lignin conversion

0.5g of Chinese toon organic solvent lignin, 0.5g of RuW/HY₃₀Catalyst (3.5 wt% Ru,20 wt% W), 6.5mL deionized water was added to a 20mL Teflon lined reactor, the autoclave was sealed, the air in the reactor was replaced with argon and argon was added to 0.5MPa, the stirring speed was 800rpm, the temperature was raised to 240 ℃ and maintained for 12 h. After the reaction is finished, the reaction mixture is rapidly cooled to room temperature, the reaction mixture is subjected to centrifugal separation after air release, liquid is extracted by ethyl acetate and then is analyzed by a gas chromatography-mass spectrometer and a gas chromatograph, and the ratio of the quality of the obtained pure benzene to the quality of the lignin is the benzene yield.

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 17.5 wt%.

FIG. 4 shows the two-dimensional nuclear magnetic resonance spectrum and the corresponding structure of the extracted toona sinensis organic solvent lignin. As can be seen from FIG. 4, there are a large number of alpha-C hydroxyl, gamma-C hydroxyl and beta-O-4 ether bond structures (A) in the toona sinensis organic solvent lignin, and there are structural units B, C where polycondensation reaction occurs; the absence of H structural units, including G, S structural units, i.e. containing benzene rings, may indicate that lignin can be used to produce benzene.

Example 3

(1) Preparation of poplar organic solvent lignin raw material

70g of poplar powder, 490mL of acetone and 210mL of deionized water are added into a 1000mL acid and alkali resistant high-pressure reaction kettle, and oxygen in the kettle is replaced by nitrogen. The nitrogen in the kettle was pressurized to 0.5MPa, the reaction kettle was heated to 160 ℃ with stirring at 600rpm, and the temperature was maintained for 1 h. Then cooling to room temperature, filtering, and washing filter residue by using 90% by volume of acetone aqueous solution. Mixing filtrates, concentrating, slowly adding the concentrated solution dropwise into 2000ml of deionized water, filtering the precipitate, freeze-drying to remove water, dissolving in 100ml of acetone/methanol (volume ratio of 9:1), slowly adding dropwise into 1000ml of anhydrous ether, filtering the precipitate, and finally vacuum-drying at 60 deg.C to obtain poplar organic solvent lignin. As can be seen from the two-dimensional nuclear magnetic spectrum (figure 5) of the poplar organosolv lignin extracted and separated by the method, a large amount of alpha-C hydroxyl, gamma-C hydroxyl and beta-O-4 ether bond structures (A) exist in the poplar organosolv lignin, and a structural unit B, C for polycondensation reaction also exists; H. g, S all three structural units are present in the lignin, i.e. contain benzene rings, which indicates that lignin can be used for producing benzene.

RuW/HY₃₀The catalyst is prepared by a wet impregnation method. Before impregnation, HY₃₀The molecular sieve is burned for 4h at 550 ℃. 1.25g of ammonium metatungstate and 0.40g of ruthenium trichloride were dissolved in 15mL of deionized water, and a precursor solution containing ammonium metatungstate and ruthenium trichloride was dropwise added to a suspension containing 2g of HY₃₀Molecular sieves in 70mL of deionized water. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 1 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in an/Ar atmosphere, and the formed passivation layer can prevent the catalyst from being strongly oxidized when exposed to air. The passivated catalyst was maintained under an inert atmosphere prior to characterization and use.

(3) Reaction for preparing pure benzene by lignin conversion

0.5g poplar organic solvent lignin, 0.5g RuW/HY₃₀Catalyst (3.5 wt% Ru,20 wt% W), 6.5mL deionized water was added to a 20mL Teflon lined reactor, the autoclave was sealed, the air in the reactor was replaced with argon and argon was added to 0.5MPa, the stirring speed was 800rpm, the temperature was raised to 240 ℃ and maintained for 12 h. After the reaction is finished, the reaction mixture is rapidly cooled to room temperature, the reaction mixture is subjected to centrifugal separation after air release, liquid is extracted by ethyl acetate and then is analyzed by a gas chromatograph-mass spectrometer and a gas chromatograph, and the quality of the obtained pure benzene and the quality of the lignin are obtainedThe ratio is the benzene yield.

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 15.6 wt%.

FIG. 5 shows the two-dimensional NMR spectrum and the corresponding structure of the extracted poplar organosolv lignin. As shown in FIG. 5, the poplar organosolv lignin contains a large amount of alpha-C hydroxyl, gamma-C hydroxyl and beta-O-4 ether bond structures (A), and structural units B, C for polycondensation reaction; H. g, S all three building blocks are present in the lignin.

Example 4

(1) Preparation of willow organic solvent lignin raw material

70g of willow powder, 490mL of acetone and 210mL of deionized water are added into a 1000mL acid and alkali resistant high-pressure reaction kettle, and the oxygen in the kettle is replaced by nitrogen. The nitrogen in the kettle was pressurized to 0.5MPa, the reaction kettle was heated to 160 ℃ with stirring at 600rpm, and the temperature was maintained for 1 h. Then cooling to room temperature, filtering, and washing filter residue by using 90% by volume of acetone aqueous solution. Mixing filtrates, concentrating, slowly adding the concentrated solution dropwise into 2000ml of deionized water, filtering the precipitate, freeze drying to remove water, dissolving in 100ml of acetone/methanol (volume ratio of 9:1), slowly adding dropwise into 1000ml of anhydrous ether, filtering the precipitate, and vacuum drying at 60 deg.C to obtain willow organic solvent lignin. As can be seen from the two-dimensional nuclear magnetic spectrum (FIG. 6) of the willow organosolv lignin extracted and separated by the method, a large amount of alpha-C hydroxyl, gamma-C hydroxyl and beta-O-4 ether bond structures (A) exist in the willow organosolv lignin, and a structural unit B, C for polycondensation reaction also exists; H. g, S all three building blocks are present in the lignin.

RuW/HY₃₀The catalyst is prepared by a wet impregnation method. Before impregnation, HY₃₀The molecular sieve is burned for 4h at 550 ℃. 1.25g of ammonium metatungstate and 0.40g of ruthenium trichloride were dissolved in 15mL of deionized water, and a precursor solution containing ammonium metatungstate and ruthenium trichloride was dropwise added to a suspension containing 2g of HY₃₀70m of molecular sieveL in deionized water. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 1 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in an/Ar atmosphere, and the formed passivation layer can prevent the catalyst from being strongly oxidized when exposed to air. The passivated catalyst was maintained under an inert atmosphere prior to characterization and use.

(3) Reaction for preparing pure benzene by lignin conversion

0.5g of willow organic solvent lignin, 0.5g of RuW/HY₃₀Catalyst (3.5 wt% Ru,20 wt% W), 6.5mL deionized water was added to a 20mL Teflon lined reactor, the autoclave was sealed, the air in the reactor was replaced with argon and argon was added to 0.5MPa, the stirring speed was 800rpm, the temperature was raised to 240 ℃ and maintained for 12 h. After the reaction is finished, the reaction mixture is rapidly cooled to room temperature, the reaction mixture is subjected to centrifugal separation after air release, liquid is extracted by ethyl acetate and then is analyzed by a gas chromatography-mass spectrometer and a gas chromatograph, and the ratio of the quality of the obtained pure benzene to the quality of the lignin is the benzene yield.

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 14.5 wt%.

FIG. 6 shows the two-dimensional NMR spectrum and the corresponding structure of the isolated and extracted lignin extracted from willow organic solvent. As can be seen from FIG. 6, the willow organosolv lignin contains a large number of alpha-C hydroxyl groups, gamma-C hydroxyl groups and beta-O-4 ether bond structures (A), and also contains structural units B, C which undergo polycondensation; H. g, S all three building blocks are present in the lignin.

Example 5

(1) Preparation of eucalyptus organic solvent lignin raw material

70g of eucalyptus powder, 490mL of acetone and 210mL of deionized water are added into a 1000mL acid and alkali resistant high-pressure reaction kettle, and oxygen in the kettle is replaced by nitrogen. The nitrogen in the kettle was pressurized to 0.5MPa, the reaction kettle was heated to 160 ℃ with stirring at 600rpm, and the temperature was maintained for 1 h. Then cooling to room temperature, filtering, and washing filter residue by using 90% by volume of acetone aqueous solution. Mixing filtrates, concentrating, slowly adding the concentrated solution dropwise into 2000ml of deionized water, filtering the precipitate, freeze drying to remove water, dissolving in 100ml of acetone/methanol (volume ratio of 9:1), slowly adding dropwise into 1000ml of anhydrous ether, filtering the precipitate, and vacuum drying at 60 deg.C to obtain eucalyptus organic solvent lignin. As can be seen from the two-dimensional nuclear magnetic spectrum (figure 7) of the eucalyptus organosolv lignin extracted and separated by the method, a large amount of alpha-C hydroxyl, gamma-C hydroxyl and beta-O-4 ether bond structures (A) exist in the eucalyptus organosolv lignin, and a structural unit B, C for polycondensation reaction also exists; G. both structural units of S are present in the lignin.

(3) Reaction for preparing pure benzene by lignin conversion

Adding 0.5g of eucalyptus organic solvent lignin, 0.5g of RuW/HY₃₀Catalyst (3.5 wt% Ru,20 wt% W), 6.5mL deionized water was added to a 20mL Teflon lined reactor, the autoclave was sealed, the air in the reactor was replaced with argon and the argon was charged to 0.5MPa, and the stirring speed was adjustedThe temperature is 800rpm, the temperature is increased to 240 ℃, and the temperature is maintained for 12 h. After the reaction is finished, the reaction mixture is rapidly cooled to room temperature, the reaction mixture is subjected to centrifugal separation after air release, liquid is extracted by ethyl acetate and then is analyzed by a gas chromatography-mass spectrometer and a gas chromatograph, and the ratio of the quality of the obtained pure benzene to the quality of the lignin is the benzene yield.

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 13.1 wt%.

FIG. 7 shows the two-dimensional NMR spectrum and the corresponding structure of the extracted eucalyptus organosolv lignin. As can be seen from FIG. 7, the eucalyptus organosolv lignin contains a large number of alpha-C hydroxyl groups, gamma-C hydroxyl groups and beta-O-4 ether bond structures (A), and also contains structural units B, C which undergo polycondensation; the H structural unit is absent and comprises G, S structural units.

Example 6

(1) Preparation of pine wood organic solvent lignin raw material

70g of pine wood powder, 490mL of acetone and 210mL of deionized water are added into a 1000mL acid and alkali resistant high pressure reaction kettle, and oxygen in the kettle is replaced by nitrogen. The nitrogen in the kettle was pressurized to 0.5MPa, the reaction kettle was heated to 160 ℃ with stirring at 600rpm, and the temperature was maintained for 1 h. Then cooling to room temperature, filtering, and washing filter residue by using 90% by volume of acetone aqueous solution. Mixing filtrates, concentrating, slowly adding the concentrated solution dropwise into 2000ml of deionized water, filtering the precipitate, freeze drying to remove water, dissolving in 100ml of acetone/methanol (volume ratio of 9:1), slowly adding dropwise into 1000ml of anhydrous ether, filtering the precipitate, and vacuum drying at 60 deg.C to obtain pine wood organic solvent lignin. Extracting multiple batches of pine wood organic solvent lignin according to the same method, and mixing for later use.

RuW/HY₃₀The catalyst is prepared by a wet impregnation method. Before impregnation, HY₃₀The molecular sieve is burned for 4h at 550 ℃. 62.50g of ammonium metatungstate and 20.00g of ruthenium trichloride were dissolved in 750mL of deionized water, and a precursor solution containing ammonium metatungstate and ruthenium trichloride was droppedAdding to suspended 60gHY₃₀3500mL of deionized water for molecular sieve. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 2 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in an/Ar atmosphere, and the formed passivation layer can prevent the catalyst from being strongly oxidized when exposed to air. The passivated catalyst was maintained under an inert atmosphere prior to characterization and use.

(3) Reaction for preparing pure benzene by lignin conversion

50.0g of pine wood organic solvent lignin, 50.0g of RuW/HY₃₀Catalyst (3.5 wt% Ru,20 wt% W), 6.5mL deionized water was added to a 20mL Teflon lined reactor, the autoclave was sealed, the air in the reactor was replaced with argon and argon was added to 0.5MPa, the stirring speed was 800rpm, the temperature was raised to 250 ℃ and maintained for 12 h. After the reaction is finished, quickly cooling to room temperature, discharging gas, centrifugally separating the reaction mixture, directly weighing the separated last time liquid which is pure benzene to obtain the yield of the pure benzene, and using¹H NMR is used for determining the quality of the product, and the ratio of the mass of the obtained pure benzene to the mass of the lignin is the benzene yield.

(3) After the reaction, the product was pure benzene and the yield of the pure product was 17.0% as determined by GC-MS analysis.

Example 7

(1) Preparation of pine wood organic solvent lignin raw material

70g of pine wood powder, 490mL of acetone and 210mL of deionized water are added into a 1000mL acid and alkali resistant high pressure reaction kettle, and oxygen in the kettle is replaced by nitrogen. The nitrogen in the kettle was pressurized to 0.5MPa, the reaction kettle was heated to 160 ℃ with stirring at 800rpm, and the temperature was maintained for 1 h. Then cooling to room temperature, filtering, and washing filter residue by using 90% by volume of acetone aqueous solution. Mixing filtrates, concentrating, slowly adding the concentrated solution dropwise into 2000ml of deionized water, filtering the precipitate, freeze drying to remove water, dissolving in 100ml of acetone/methanol (volume ratio of 9:1), slowly adding dropwise into 1000ml of anhydrous ether, filtering the precipitate, and vacuum drying at 60 deg.C to obtain pine wood organic solvent lignin.

RuW/HY₃₀The catalyst is prepared by a wet impregnation method. Before impregnation, HY₃₀The molecular sieve is burned for 4h at 550 ℃. 1.43g of ammonium metatungstate and 0.40g of ruthenium trichloride were dissolved in 15mL of deionized water, and a precursor solution containing ammonium metatungstate and ruthenium trichloride was dropwise added to a suspension of 2gHY₃₀Molecular sieves in 70mL of deionized water. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 2 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in an/Ar atmosphere, and the formed passivation layer can prevent the catalyst from being strongly oxidized when exposed to air. The passivated catalyst was maintained under an inert atmosphere prior to characterization and use.

(3) Reaction for preparing pure benzene by lignin conversion

Adding 0.5g pine wood organic solvent lignin, 0.5g RuW/HY₃₀Catalyst (4.0 wt% Ru,20 wt% W), 6.5mL deionized water was added to a 20mL Teflon lined reactor, the autoclave was sealed, the air in the reactor was replaced with argon and argon was added to 0.5MPa, the stirring speed was 800rpm, the temperature was raised to 250 ℃ and maintained for 12 h. After the reaction is finished, the reaction mixture is rapidly cooled to room temperature, the reaction mixture is subjected to centrifugal separation after air release, liquid is extracted by ethyl acetate and then is analyzed by a gas chromatography-mass spectrometer and a gas chromatograph, and the ratio of the quality of the obtained pure benzene to the quality of the lignin is the benzene yield.

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 18.2 wt%.

Example 8

(1) Preparation of pine wood organic solvent lignin raw material

RuW/HY₃₀The catalyst is prepared by a wet impregnation method. Before impregnation, HY₃₀The molecular sieve is burned for 4h at 550 ℃. 1.43g of ammonium metatungstate and 0.60g of ruthenium trichloride were dissolved in 15mL of deionized water, and a precursor solution containing ammonium metatungstate and ruthenium trichloride was dropwise added to a suspension of 2gHY₃₀Molecular sieves in 70mL of deionized water. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 2 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in an/Ar atmosphere, and the formed passivation layer can prevent the catalyst from being strongly oxidized when exposed to air. The passivated catalyst was maintained under an inert atmosphere prior to characterization and use.

(3) Reaction for preparing pure benzene by lignin conversion

Adding 0.5g pine wood organic solvent lignin, 0.5g RuW/HY₃₀Catalyst (4.0 wt% Ru,30 wt% W), 6.5mL deionized water was added to a 20mL Teflon lined reactor, the autoclave was sealed, the air in the reactor was replaced with argon and argon was added to 0.5MPa, the stirring speed was 800rpm, the temperature was raised to 250 ℃ and maintained for 12 h. After the reaction is finished, quickly cooling to room temperature, and deflatingAnd (3) centrifugally separating the reaction mixture, extracting the liquid by using ethyl acetate, and analyzing by using a gas chromatography-mass spectrometer and a gas chromatograph to obtain the ratio of the mass of the pure benzene to the mass of the lignin, namely the benzene yield.

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 14.1 wt%.

Example 9

(1) Preparation of pine wood organic solvent lignin raw material

70g of pine wood powder, 490mL of acetone and 210mL of deionized water are added into a 1000mL acid and alkali resistant high pressure reaction kettle, and oxygen in the kettle is replaced by nitrogen. The nitrogen in the kettle was pressurized to 0.5MPa, the reaction kettle was heated to 160 ℃ with stirring at 600rpm, and the temperature was maintained for 1 h. Then cooling to room temperature, filtering, and washing filter residue by using 90% by volume of acetone aqueous solution. Mixing filtrates, concentrating, slowly adding the concentrated solution dropwise into 2000ml of deionized water, filtering the precipitate, freeze drying to remove water, dissolving in 100ml of acetone/methanol (volume ratio of 9:1), slowly adding dropwise into 1000ml of anhydrous ether, filtering the precipitate, and vacuum drying at 60 deg.C to obtain pine wood organic solvent lignin.

(2) Preparation of ruthenium-tungsten alloy loaded ZSM-5 molecular sieve catalyst (RuW/ZSM-5)

The RuW/ZSM-5 catalyst is prepared by a wet impregnation method. Prior to impregnation, the ZSM-5 molecular sieve (Si to Al atomic ratio 235) was calcined at 550 ℃ for 4 h. 1.25g of ammonium metatungstate and 0.40g of ruthenium trichloride were dissolved in 15mL of deionized water, and a precursor solution containing ammonium metatungstate and ruthenium trichloride was dropwise added to a suspension containing 2g of HY₃₀Molecular sieves in 70mL of deionized water. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 1 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in an/Ar atmosphere, and the formed passivation layer can prevent the catalyst from being strongly oxidized when exposed to air. The passivated catalysis was carried out before characterization and useThe agent is maintained under an inert atmosphere.

(3) Reaction for preparing pure benzene by lignin conversion

0.5g of pine organic solvent lignin, 0.5g of RuW/ZSM-5 catalyst (3.5 wt% Ru,20 wt% W) and 6.5mL of deionized water are added into a 20mL polytetrafluoroethylene-lined reaction kettle, the reaction kettle is sealed, air in the kettle is replaced by argon, the argon is filled to 0.5MPa, the stirring speed is 800rpm, the temperature is increased to 240 ℃, and the reaction kettle is maintained for 12 hours. After the reaction is finished, the reaction mixture is rapidly cooled to room temperature, the reaction mixture is subjected to centrifugal separation after air release, liquid is extracted by ethyl acetate and then is analyzed by a gas chromatography-mass spectrometer and a gas chromatograph, and the ratio of the quality of the obtained pure benzene to the quality of the lignin is the benzene yield.

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 11.9 wt%.

Example 10

(1) Preparation of pine wood organic solvent lignin raw material

70g of pine wood powder, 500mL of dioxane, 200mL of deionized water and 7g of hydrochloric acid (the mass percentage concentration is 37%) are added into a 1000mL acid-alkali-resistant high-pressure reaction kettle, and nitrogen is used for replacing oxygen in the kettle. The nitrogen in the kettle is pressurized to 1MPa, the reaction kettle is heated to 100 ℃ under the stirring of 800rpm, and the temperature is kept for 1 h. Then cooling to room temperature, filtering, and washing filter residue by using 90% by volume of acetone aqueous solution. Mixing filtrates, concentrating, slowly adding the concentrated solution dropwise into 2000ml of deionized water, filtering the precipitate, freeze drying to remove water, dissolving in 100ml of acetone/methanol (volume ratio of 9:1), slowly adding dropwise into 1000ml of anhydrous ether, filtering the precipitate, and vacuum drying at 60 deg.C to obtain pine wood organic solvent lignin.

RuW/HY₃₀The catalyst is prepared by a wet impregnation method. Before impregnation, HY₃₀The molecular sieve is burned for 4h at 550 ℃. 1.25g of ammonium metatungstate and 0.40g of ruthenium trichloride were dissolved in 15mL of deionized water, and a precursor solution containing ammonium metatungstate and ruthenium trichloride was dropwise added to the suspensionHas 2gHY₃₀Molecular sieves in 70mL of deionized water. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 2 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in an/Ar atmosphere, and the formed passivation layer can prevent the catalyst from being strongly oxidized when exposed to air. The passivated catalyst was maintained under an inert atmosphere prior to characterization and use.

(3) Reaction for preparing pure benzene by lignin conversion

Adding 0.5g pine wood organic solvent lignin RuW/HY₃₀Catalyst (3.5 wt% Ru,20 wt% W), 6.5mL deionized water was added to a 20mL Teflon lined reactor, the autoclave was sealed, the air in the reactor was replaced with argon and argon was added to 0.5MPa, the stirring speed was 800rpm, the temperature was raised to 250 ℃ and maintained for 12 h. After the reaction is finished, the reaction mixture is rapidly cooled to room temperature, the reaction mixture is subjected to centrifugal separation after air release, liquid is extracted by ethyl acetate and then is analyzed by a gas chromatography-mass spectrometer and a gas chromatograph, and the ratio of the quality of the obtained pure benzene to the quality of the lignin is the benzene yield.

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 17.7 wt%.

Example 11

(1) Preparation of pine wood organic solvent lignin raw material

70g of pine wood powder, 500mL of ethanol, 200mL of deionized water and 7g of hydrochloric acid (the mass percentage concentration is 37%) are added into a 1000mL acid-alkali-resistant high-pressure reaction kettle, and nitrogen is used for replacing oxygen in the kettle. The nitrogen in the kettle is pressurized to 1MPa, the reaction kettle is heated to 100 ℃ under the stirring of 800rpm, and the temperature is kept for 1 h. Then cooling to room temperature, filtering, and washing filter residue by using 90% by volume of acetone aqueous solution. Mixing filtrates, concentrating, slowly adding the concentrated solution dropwise into 2000ml of deionized water, filtering the precipitate, freeze drying to remove water, dissolving in 100ml of acetone/methanol (volume ratio of 9:1), slowly adding dropwise into 1000ml of anhydrous ether, filtering the precipitate, and vacuum drying at 60 deg.C to obtain pine wood organic solvent lignin.

RuW/HY₃₀The catalyst is prepared by a wet impregnation method. Before impregnation, HY₃₀The molecular sieve is burned for 4h at 550 ℃. 1.25g of ammonium metatungstate and 0.40g of ruthenium trichloride were dissolved in 15mL of deionized water, and a precursor solution containing ammonium metatungstate and ruthenium trichloride was dropwise added to a suspension containing 2g of HY₃₀Molecular sieves in 70mL of deionized water. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 2 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in an/Ar atmosphere, and the formed passivation layer can prevent the catalyst from being strongly oxidized when exposed to air. The passivated catalyst was maintained under an inert atmosphere prior to characterization and use.

(3) Reaction for preparing pure benzene by lignin conversion

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 17.1 wt%.

Example 12

(1) Preparation of pine wood organic solvent lignin raw material

70g of pine wood powder, 500mL of dioxane, 200mL of deionized water and 3.5g of hydrochloric acid (the mass percentage concentration is 37%) are added into a 1000mL acid-alkali-resistant high-pressure reaction kettle, and nitrogen is used for replacing oxygen in the kettle. The nitrogen in the kettle is pressurized to 1MPa, the reaction kettle is heated to 110 ℃ under the stirring of 800rpm, and the temperature is kept for 1 h. Then cooling to room temperature, filtering, and washing filter residue by using 90% by volume of acetone aqueous solution. Mixing filtrates, concentrating, slowly adding the concentrated solution dropwise into 2000ml of deionized water, filtering the precipitate, freeze drying to remove water, dissolving in 100ml of acetone/methanol (volume ratio of 9:1), slowly adding dropwise into 1000ml of anhydrous ether, filtering the precipitate, and vacuum drying at 60 deg.C to obtain pine wood organic solvent lignin.

(3) Reaction for preparing pure benzene by lignin conversion

Adding 0.5g pine wood organic solvent lignin, 0.5g RuW/HY₃₀Adding a catalyst (3.5 wt% Ru and 20 wt% W) and 6.5mL of deionized water into a 20mL polytetrafluoroethylene-lined reaction kettle, sealing the reaction kettle, replacing the air in the kettle with argon, filling the argon to 0.5MPa, stirring at the speed of 800rpm, heating to 240 ℃, and maintaining for 12h. After the reaction is finished, the reaction mixture is rapidly cooled to room temperature, the reaction mixture is subjected to centrifugal separation after air release, liquid is extracted by ethyl acetate and then is analyzed by a gas chromatography-mass spectrometer and a gas chromatograph, and the ratio of the quality of the obtained pure benzene to the quality of the lignin is the benzene yield.

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 14.4 wt%.

Example 13

(1) Preparation of pine wood organic solvent lignin raw material

(2) HY loaded ruthenium-tungsten alloy₄₀Molecular sieve catalyst (RuW/HY)₄₀) Preparation of

RuW/HY₄₀The catalyst is prepared by a wet impregnation method. Before impregnation, HY₄₀The molecular sieve (HY molecular sieve has Si/Al atomic ratio of 40, the same below) is calcined at 550 deg.C for 4 h. 1.25g of ammonium metatungstate and 0.40g of ruthenium trichloride were dissolved in 15mL of deionized water, and a precursor solution containing ammonium metatungstate and ruthenium trichloride was dropwise added to a suspension containing 2g of HY₄₀Molecular sieves in 70mL of deionized water. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 1 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in/Ar atmosphereThe passivation layer can prevent the catalyst from being oxidized strongly when exposed to air. The passivated catalyst was maintained under an inert atmosphere prior to characterization and use.

(3) Reaction for preparing pure benzene by lignin conversion

Adding 0.5g pine wood organic solvent lignin, 0.5g RuW/HY₄₀Catalyst (3.5 wt% Ru,20 wt% W), 6.5mL deionized water was added to a 20mL Teflon lined reactor, the autoclave was sealed, the air in the reactor was replaced with argon and argon was added to 0.5MPa, the stirring speed was 800rpm, the temperature was raised to 240 ℃ and maintained for 12 h. After the reaction is finished, the reaction mixture is rapidly cooled to room temperature, the reaction mixture is subjected to centrifugal separation after air release, liquid is extracted by ethyl acetate and then is analyzed by a gas chromatography-mass spectrometer and a gas chromatograph, and the ratio of the quality of the obtained pure benzene to the quality of the lignin is the benzene yield.

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 15.9 wt%.

Example 14

(1) Preparation of pine wood organic solvent lignin raw material

RuW/HY₄₀The catalyst is prepared by a wet impregnation method. Before impregnation, HY₄₀The molecular sieve is burned for 4h at 550 ℃. 1.25g of ammonium metatungstate and 0.40g of ruthenium trichloride were dissolved inIn 15mL of deionized water, a precursor solution containing ammonium metatungstate and ruthenium trichloride is dropwise added into the deionized water in which 2g HY is suspended₄₀Molecular sieves in 70mL of deionized water. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 1 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in an/Ar atmosphere, and the formed passivation layer can prevent the catalyst from being strongly oxidized when exposed to air. The passivated catalyst was maintained under an inert atmosphere prior to characterization and use.

(3) Reaction for preparing pure benzene by lignin conversion

Example 15

(1) Preparation of pine wood organic solvent lignin raw material

(3) Reaction for preparing pure benzene by lignin conversion

Adding 0.5g pine wood organic solvent lignin, 0.5g RuW/HY₃₀Catalyst (3.5 wt% Ru,20 wt% W), 6.5mL deionized water was added to a 20mL Teflon lined reactor, the autoclave was sealed, the air in the reactor was replaced with argon and hydrogen was charged to 0.5MPa, the stirring speed was 800rpm, the temperature was raised to 240 ℃ and maintained for 12 h. After the reaction is finished, the reaction mixture is rapidly cooled to room temperature, the reaction mixture is subjected to centrifugal separation after air release, liquid is extracted by ethyl acetate and then is analyzed by a gas chromatography-mass spectrometer and a gas chromatograph, and the ratio of the quality of the obtained pure benzene to the quality of the lignin is the benzene yield.

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 10.6 wt%.

Example 16

(1) Preparation of pine wood organic solvent lignin raw material

(3) Reaction for preparing pure benzene by lignin conversion

Adding 0.5g pine wood organic solvent lignin, 1.0g RuW/HY₃₀Adding a catalyst (3.5 wt% Ru and 20 wt% W) and 8.0mL of deionized water into a 20mL polytetrafluoroethylene-lined reaction kettle, sealing the reaction kettle, replacing the air in the kettle with argon, filling the argon to 0.5MPa, stirring at the speed of 800rpm, and heating to 240 DEG CKeeping the temperature for 12 h. After the reaction is finished, the reaction mixture is rapidly cooled to room temperature, the reaction mixture is subjected to centrifugal separation after air release, liquid is extracted by ethyl acetate and then is analyzed by a gas chromatography-mass spectrometer and a gas chromatograph, and the ratio of the quality of the obtained pure benzene to the quality of the lignin is the benzene yield.

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 17.6 wt%.

Example 17

(1) Preparation of pine wood organic solvent lignin raw material

RuW/HY₃₀The catalyst is prepared by a wet impregnation method. Before impregnation, HY₃₀The molecular sieve is burned for 4h at 550 ℃. 1.25g of ammonium metatungstate and 0.40g of ruthenium trichloride were dissolved in 15mL of deionized water, and a precursor solution containing ammonium metatungstate and ruthenium trichloride was dropwise added to a suspension containing 2g of HY₃₀Molecular sieves in 70mL of deionized water. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 1 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in/Ar atmosphere, and the formed passivation layer can prevent the catalystIs strongly oxidized when exposed to air. The passivated catalyst was maintained under an inert atmosphere prior to characterization and use.

(3) Reaction for preparing pure benzene by lignin conversion

Adding 0.5g pine wood organic solvent lignin, 0.5g RuW/HY₃₀Catalyst (3.5 wt% Ru,20 wt% W), 6.5mL deionized water was added to a 20mL Teflon lined reactor, the autoclave was sealed, the air in the reactor was replaced with argon and argon was added to 0.5MPa, the stirring speed was 800rpm, the temperature was raised to 240 ℃ and maintained for 24 h. After the reaction is finished, the reaction mixture is rapidly cooled to room temperature, the reaction mixture is subjected to centrifugal separation after air release, liquid is extracted by ethyl acetate and then is analyzed by a gas chromatography-mass spectrometer and a gas chromatograph, and the ratio of the quality of the obtained pure benzene to the quality of the lignin is the benzene yield.

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 18.1 wt%.

Example 18

(1) Preparation of pine wood organic solvent lignin raw material

RuW/HY₃₀The catalyst is prepared by a wet impregnation method. Before impregnation, HY₃₀The molecular sieve is burned for 4h at 550 ℃. 1.25g of ammonium metatungstate and 0.40g of ruthenium trichloride were dissolved in 15mL of deionized water to obtain a solution containing metatungstenAmmonium salt and ruthenium trichloride

The precursor solution of (2 g) HY suspended in a liquid₃₀Molecular sieves in 70mL of deionized water. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 1 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in an/Ar atmosphere, and the formed passivation layer can prevent the catalyst from being strongly oxidized when exposed to air. The passivated catalyst was maintained under an inert atmosphere prior to characterization and use.

(3) Reaction for preparing pure benzene by lignin conversion

Adding 0.5g pine wood organic solvent lignin, 0.5g RuW/HY₃₀Catalyst (3.5 wt% Ru,20 wt% W), 6.5mL deionized water was added to a 20mL Teflon lined reactor, the autoclave was sealed, the air in the reactor was replaced with argon and argon was added to 0.5MPa, the stirring speed was 800rpm, the temperature was raised to 260 ℃ and maintained for 12 h. After the reaction is finished, the reaction mixture is rapidly cooled to room temperature, the reaction mixture is subjected to centrifugal separation after air release, liquid is extracted by ethyl acetate and then is analyzed by a gas chromatography-mass spectrometer and a gas chromatograph, and the ratio of the quality of the obtained pure benzene to the quality of the lignin is the benzene yield.

(4) After the reaction, the product was mainly pure benzene as seen by GC-MS and GC analysis, and the yield was 17.2 wt%.

Example 19

(1) Preparation of pine wood organic solvent lignin raw material

RuW/HY₃₀The catalyst is prepared by a wet impregnation method. Before impregnation, HY₃₀The molecular sieve (the atomic ratio of Si and Al of HY molecular sieve is specifically 30) is calcined at 550 ℃ for 4 h. 1.25g of ammonium metatungstate and 0.40g of ruthenium trichloride were dissolved in 15mL of deionized water, and a precursor solution containing ammonium metatungstate and ruthenium trichloride was dropwise added to a suspension containing 2g of HY₃₀Molecular sieves in 70mL of deionized water. The mixture was stirred vigorously for 48h, dewatered under reduced pressure and dried at 200 ℃ for 16 h. The catalyst mixture prepared was in a continuous 10% H₂Reducing in Ar, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, then heating to 900 ℃ at the speed of 1 ℃/min, and then keeping at 900 ℃ for 1 h. After cooling to room temperature, the reduced catalyst was exposed to 1% O₂Passivating for 1h in an/Ar atmosphere, and the formed passivation layer can prevent the catalyst from being strongly oxidized when exposed to air. The passivated catalyst was maintained under an inert atmosphere prior to characterization and use.

(3) Reaction for preparing pure benzene by lignin conversion

Adding 0.5g pine wood organic solvent lignin, 0.5g RuW/HY₃₀Catalyst (3.5 wt% Ru,20 wt% W), 6.5mL deionized water was added to a 20mL Teflon lined reactor, the autoclave was sealed (no argon was used to replace the air in the reactor), the stirring speed was 800rpm, the temperature was raised to 240 ℃ and maintained for 12 h. After the reaction, the reaction mixture was rapidly cooled to room temperature (25 ℃), the reaction mixture was centrifuged after gassing, the liquid was extracted with ethyl acetate and then gas chromatography-mass spectrometry was usedAnalyzing by an instrument and a gas chromatograph, and obtaining the ratio of the quality of the pure benzene to the quality of the lignin, namely the benzene yield.

(4) After the reaction, a gas chromatogram of the product is shown in FIG. 2; FIG. 3 shows the mass spectrum of the product, and GC-MS and GC analysis in FIGS. 2 and 3 show that the product is mainly pure benzene with a yield of 15.8 wt%.

Comparative examples 1,

Pure benzene was prepared by the method of example 1 except that the catalyst HY molecular sieve in example 1 (Si to Al atomic ratio of 30) was replaced with HY molecular sieve (Si to Al atomic ratio of 2.6); after the reaction, no benzene was contained in the product as seen by GC-MS and GC analysis.

Comparative examples 2,

Pure benzene was prepared by the method of example 1 except that the catalyst HY molecular sieve in example 1 (Si to Al atomic ratio of 30) was replaced with ZSM-5 molecular sieve (Si to Al atomic ratio of 15); after the reaction, no benzene was contained in the product as seen by GC-MS and GC analysis.

Comparative examples 3,

Pure benzene was prepared by the method of example 1 except that the catalyst HY molecular sieve in example 1 (Si to Al atomic ratio of 30) was replaced with a beta molecular sieve (Si to Al atomic ratio of 30); after the reaction, no benzene was contained in the product as seen by GC-MS and GC analysis.

Claims

1. A method for preparing pure benzene by catalytic conversion of lignin by a metal-supported catalyst comprises the following steps: the lignin is subjected to catalytic conversion reaction by taking a metal ruthenium-tungsten loaded high-silicon molecular sieve as a catalyst to obtain benzene;

in the ruthenium-tungsten metal-loaded high-silicon molecular sieve, the ruthenium-tungsten metal is an alloy or a mixture of ruthenium and tungsten, and the high-silicon molecular sieve is an HY molecular sieve and/or a ZSM-5 molecular sieve;

the HY molecular sieve has an atomic ratio of Si to Al of 10-50, and the ZSM-5 molecular sieve has an atomic ratio of Si to Al of 100-500;

the catalytic conversion reaction is carried out in an air atmosphere, an inert atmosphere and/or a hydrogen atmosphere.

2. The method of claim 1, wherein: in the metal ruthenium-tungsten loaded high-silicon molecular sieve, the loading capacity of ruthenium is 0.1-20% of the mass of the high-silicon molecular sieve, and the loading capacity of tungsten is 1-50% of the mass of the high-silicon molecular sieve.

3. The method according to claim 1 or 2, characterized in that: the mass of the catalyst is 10-200% of the mass of the lignin.

4. The method according to claim 1 or 2, characterized in that: the conditions of the catalytic conversion reaction are as follows: the pressure is 0.1 MPa-10 MPa; the temperature is 100-350 ℃; the time is 0.5 to 24 hours.

5. The method of claim 1, wherein: the inert atmosphere is argon and/or nitrogen;

the catalytic conversion reaction is carried out under the condition of introducing hydrogen: the amount of hydrogen introduced into each gram of lignin is 0-10 mmol.

6. The method according to claim 1 or 2, characterized in that: the catalytic conversion reaction is carried out under the condition of stirring;

the catalytic conversion reaction is carried out in a solvent.

7. The method of claim 6, wherein: the stirring speed is 400 rpm-1000 rpm;

the solvent is water;

the mass ratio of the water to the lignin is 5-50: 1.

8. The method according to claim 1 or 2, characterized in that: the raw material for extracting the lignin is at least one of poplar, pine, willow, cedar, elm, heaven tree, peach, fruit tree, fir, eucalyptus and moso bamboo.

9. The method of claim 8, wherein: the method for extracting the lignin comprises the following steps: hydrolyzing the wood flour of the raw material with high-temperature water or acid hydrolysis in an organic solvent and water to obtain the lignin;

the temperature of the high-temperature water hydrolysis or acid hydrolysis is 80-200 ℃.

10. The method of claim 9, wherein: the organic solvent is at least one of acetone, butanone, ethanol, isopropanol and dioxane;

the volume ratio of the organic solvent to the water is 1-9: 1;

the mass ratio of the total volume of the organic solvent and the water to the wood powder is 5-15 mL:1 g; and/or

The acid in the acid hydrolysis is hydrochloric acid; the mass ratio of the hydrochloric acid to the wood powder is 0-1: 1; and/or

The time for hydrolyzing the high-temperature water or the acid is 0.5 to 6 hours;

the high-temperature water hydrolysis or acid hydrolysis is carried out under the condition of stirring;

the high temperature water hydrolysis or acid hydrolysis is carried out in an inert atmosphere.

11. The method of claim 10, wherein: the stirring speed is 400 rpm-1600 rpm;

the inert atmosphere is nitrogen and/or argon, and the pressure of the inert gas is 0.5 MPa-1 MPa.