Preparation methods and applications of ruthenium metal-supported nickel aluminate spinel catalysts

Abstract

This invention discloses a method for preparing a ruthenium metal-supported nickel aluminate spinel catalyst and its application. The prepared ruthenium metal-supported nickel aluminate spinel catalyst is applied to a co-solvent of water and an organic molecular hydrogen donor to achieve catalytic transfer hydrogenation of lignin derivatives for the preparation of bio-based chemicals. By adjusting the ruthenium metal loading to control the metal sites provided by zero-valent ruthenium and the Lewis acid sites provided by ruthenium oxide, the characteristics of the bifunctional catalyst are modulated. By adjusting the solvent ratio of the organic molecular hydrogen donor and water, the in-situ hydrogen production efficiency and solvent activity of the co-solvent system are controlled, enabling the hydrogen donor to efficiently produce hydrogen and undergo hydrogen transfer on its surface, thus achieving an ultra-high conversion rate of lignin derivatives. This reaction is mild, requires no external hydrogen, and yields high amounts of bio-based chemicals, providing a novel and sustainable method for the preparation of bio-based chemicals.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection and comprehensive resource utilization of nanocatalytic materials technology, specifically involving a method for preparing a ruthenium metal-supported nickel aluminate spinel catalyst and the application of lignin derivatives in the catalytic transfer hydrogenation of water and organic molecule hydrogen donor co-solvents to prepare bio-based chemicals. Background Technology

[0002] Lignin, as the only abundant naturally occurring aromatic compound, can be depolymerized and transformed to produce high-value fine platform chemicals, serving as a substitute for fossil-based products. The oxygen-to-carbon ratio (O / C) of lignin is 0.3-0.5, and this ratio remains unchanged after catalytic depolymerization via acids, alkalis, ionic liquids, or pyrolysis. This high oxygen content severely limits the practical application of the product, necessitating a hydrodeoxygenation strategy to improve product quality.

[0003] The hydrodeoxygenation process of lignin derivatives inevitably requires a large amount of hydrogen donors. Currently, the most widely used exogenous hydrogen is usually produced by steam reforming of fossil fuels such as coal, oil, and natural gas. Furthermore, the catalytic reaction requires high temperature (>200℃) and high pressure (>2MPa) conditions to activate the molecular hydrogen on the catalyst surface, significantly increasing environmental costs and safety hazards. Therefore, there is an urgent need to develop a sustainable hydrogen source. Catalytic transfer hydrogenation utilizes organic molecules (methanol, formic acid, ethanol, isopropanol, naphthalene, etc.) as reaction media and hydrogen donors. Under the action of a catalyst, hydrogen is produced in situ and acts on the reaction substrate to achieve its efficient value-added conversion, which is considered a feasible alternative strategy.

[0004] Bio-based chemicals have become a promising source in current chemical production due to their sustainability and widespread accessibility. For example, adipic acid and ε-caprolactam are important precursors for the industrial synthesis of nylon, currently produced via cyclohexanol and cyclohexanone (KA oil) as intermediates. The bio-oil obtained from lignin depolymerization contains a large number of phenolic compounds, including phenol, guaiacol, and alkylphenols, which can serve as a bio-based source of KA oil. Lignin is composed of three aromatic structural units (coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol) interconnected and randomly coupled via C-C and CO bonds, exhibiting significant heterogeneity and structural complexity. Its derivatives contain chemical bonds (CO and C-C) with different bond energies, which are highly representative of lignin. Exploring the catalytic conversion characteristics of lignin derivatives can simplify complex processes and provide a reference for the preparation of bio-based chemicals from lignin polymers.

[0005] The key to catalytic transfer hydrogenation lies in developing efficient solvent hydrogen-donating systems and high-performance catalysts. Studies have shown that some organic molecules, through a trade-off between Lewis basicity and polarity with hydrogen-donating capacity, exhibit dual characteristics as both reaction media and hydrogen donors, and can also act as nucleophiles to accelerate the cleavage of ether bonds in lignin. Water can interact with active sites on the catalyst surface, exhibiting superior solvent activity compared to organic molecules, thus promoting hydrogen exchange and transfer. Therefore, using a suitable ratio of organic molecules and water as a co-solvent can achieve good synergistic effects. The development of catalytic transfer hydrogenation catalysts needs to simultaneously consider the catalyst's hydrogen activation capacity for the hydrogen donor and its catalytic hydrogenolysis and hydrogenation capacity for the substrate. Bifunctional heterogeneous catalysts with both metal and acid sites show good synergistic effects in both aspects. Group VIIB and IB metals have good dehydrogenation performance; among them, ruthenium, platinum, palladium, and rhodium exhibit suitable hydrogen adsorption and desorption capabilities and excellent catalytic hydrogenation capacity. Ruthenium-based catalysts have significant advantages over other noble metals due to their moderate cost and excellent demethoxylation ability and good catalytic activity. Furthermore, nickel aluminate spinel exhibits excellent thermal and chemical stability due to its unique partially inverted structure. It also promotes the reduction of supported metals, facilitates solvent dehydrogenation at the catalyst interface, and provides favorable oxygen vacancies and acid sites. Therefore, introducing nickel aluminate as a support can improve the stability of the catalyst and the efficiency of catalytic transfer hydrogenation. Summary of the Invention

[0006] The present invention aims to provide a method for preparing a ruthenium metal-supported nickel aluminate spinel catalyst and its application. The invention relates to two aspects: the preparation process of the ruthenium metal-supported nickel aluminate spinel catalyst, and a method for catalyzing the in-situ hydrogenation of lignin derivatives in a co-solvent of water and an organic molecule hydrogen donor to prepare bio-based chemicals.

[0007] This invention relates to a method for the catalytic transfer hydrogenation of lignin derivatives to prepare bio-based chemicals in a co-solvent system of water and an organic molecule hydrogen donor, using a ruthenium metal-supported nickel aluminate spinel catalyst. By controlling the catalyst metal loading, this invention screens for highly active ruthenium metal-supported nickel aluminate spinel catalysts to catalyze the preparation of bio-based chemicals from lignin derivatives in a co-solvent system of water and an organic molecule hydrogen donor. This process provides a more efficient and sustainable method for the preparation of bio-based chemicals, avoiding the use of high-pressure external hydrogen, and has significant practical implications for the development of the bio-based chemical industry, biomass energy, and the resource utilization of lignin.

[0008] The present invention proposes a method for preparing a ruthenium metal-supported nickel aluminate spinel catalyst, the specific steps of which are as follows:

[0009] (1) Dissolve the nickel precursor and the aluminum precursor in ultrapure water in sequence at a Ni / Al molar ratio of 1 / 8-1 / 2, and stir vigorously to mix them thoroughly to obtain a metal salt solution.

[0010] (2) Add ammonia solution dropwise to the metal salt solution obtained in step (1) while stirring until the metal salt solution becomes alkaline and a uniform viscous paste-like liquid is obtained.

[0011] (3) Stir the viscous paste liquid obtained in step (2) evenly at room temperature and let it stand to age;

[0012] (4) Centrifuge the layered paste liquid obtained in step (3) to separate the solid and liquid, and wash the solid precipitate with ultrapure water multiple times until the filtrate reaches neutrality;

[0013] (5) The precipitate obtained in step (4) is placed in an oven to dry, and then ground and sieved.

[0014] (6) Place the powder obtained in step (5) in a tube furnace, heat it to a set temperature under a nitrogen atmosphere and calcine it, then cool it to room temperature to obtain nickel aluminate spinel carrier.

[0015] (7) Dissolve the ruthenium precursor in ultrapure water and stir until completely dissolved to obtain an aqueous solution of the ruthenium precursor;

[0016] (8) Add the nickel aluminate spinel obtained in step (6) to the aqueous solution of the ruthenium precursor obtained in step (7) and stir continuously to obtain a solid suspension. Stir vigorously at room temperature. The mass ratio of ruthenium to nickel aluminate spinel is (0.005-0.2):1.

[0017] (9) The solid suspension obtained in step (8) is evaporated to dryness by rotary evaporation to obtain primary solid powder;

[0018] (10) Place the primary solid powder obtained in step (9) in an oven to dry, cool to room temperature and grind and sieve to obtain secondary solid powder;

[0019] (11) The secondary solid powder obtained in step (10) is placed in a tube furnace, heated and calcined under a nitrogen atmosphere, and cooled to room temperature to obtain tertiary solid powder;

[0020] (12) The tertiary solid powder obtained in step (11) is placed in a tube furnace and heated and reduced in a mixed atmosphere of hydrogen and nitrogen. After cooling to room temperature, ruthenium metal supported nickel aluminate spinel catalyst is obtained.

[0021] In this invention, the precursor of nickel in step (1) includes, but is not limited to, any one of nickel hydrated nitrate, nickel hydrated acetate, or nickel hydrated chlorate; the precursor of aluminum includes, but is not limited to, any one of aluminum hydrated nitrate, aluminum hydrated acetate, or aluminum hydrated chlorate.

[0022] In this invention, in step (6), the powder is calcined at 400-800℃ for 1-10 hours in a nitrogen atmosphere.

[0023] In this invention, the precursor of ruthenium in step (7) includes, but is not limited to, any one of ruthenium chloride, ruthenium oxide, ruthenium nitrate, ruthenium acetate, or ruthenium acetylacetonate.

[0024] In this invention, the solid suspension obtained in step (8) is stirred vigorously at room temperature for 1-24 hours.

[0025] In this invention, the primary solid powder obtained in step (10) is dried in an oven at 50-100°C for 4-12 hours.

[0026] In this invention, the secondary solid powder obtained in step (11) is heated to 100-800℃ under a nitrogen atmosphere and kept at that temperature for 0.5-5h.

[0027] In this invention, the tertiary solid powder obtained in step (12) is heated to 150-400°C in a mixed atmosphere of hydrogen and nitrogen and kept at that temperature for 0.5-5 hours.

[0028] The present invention provides an application of ruthenium metal-supported nickel aluminate spinel catalyst in the production of bio-based chemicals. Specifically, it describes the in-situ hydrogen production catalysis of lignin derivatives to prepare bio-based chemicals using nickel aluminate spinel supported on ruthenium metal as a catalyst in an organic molecular hydrogen donor and an aqueous co-solvent. The specific steps are as follows:

[0029] (1) Add the ruthenium metal-supported nickel aluminate spinel catalyst to a co-solvent consisting of water and an organic molecular hydrogen donor containing lignin derivatives to obtain a mixture; the mass ratio of ruthenium metal-supported nickel aluminate spinel to lignin derivatives is 0.06-0.6:1;

[0030] (2) Add the mixture obtained in step (1) into a hydrothermal reactor, fill it with argon gas, stir and heat it to the set temperature, and maintain the reaction at that temperature;

[0031] (3) After the reaction in step (2) is completed, cool down;

[0032] (4) The product obtained after cooling in step (3) is subjected to centrifugal solid-liquid separation and extraction to obtain an organic phase;

[0033] (5) The organic solvent is removed by rotary evaporation of the organic phase obtained in step (4) to obtain the target product.

[0034] In this invention, the lignin derivative mentioned in step (1) is any one of benzene, phenol, anisole, toluene, ethylbenzene, benzaldehyde, acetophenone, styrene, cyclohexanone, cyclohexanol, guaiacol, 3-methoxyphenol, 4-methoxyphenol, 3,4-dimethoxyphenol, 3,5-dimethoxyphenol, 2,3-dimethoxyphenol, 2,4-dimethoxyphenol, 2,5-dimethoxyphenol, 2,6-dimethoxyphenol, catechol, 4-ethylphenol, 4-methylguaiacol, 4-ethylguaiacol, 4-hydroxy-3-methoxybenzyl alcohol, vanillin, 4'-hydroxy-3'-methoxyacetophenone, diphenyl ether, benzylphenyl ether, phenoxyethylbenzene, or 2-phenoxy-1-phenylethanol.

[0035] In this invention, the organic hydrogen donor mentioned in step (1) is any one of methanol, ethanol, ethylene glycol, n-propanol, isopropanol, glycerol, n-butanol, formic acid, or naphthalene.

[0036] In this invention, in step (2), after adding the mixture obtained in step (1) to the hydrothermal reactor, the reactor is sealed and evacuated to a vacuum, Ar at 0-20 bar is introduced, and the mixture is stirred and heated to any temperature value between 100-300°C, and the reaction is maintained at this temperature for 0.5-5 hours.

[0037] This invention discloses an effective preparation condition for a ruthenium metal-supported nickel aluminate spinel catalyst. This process is mild and yields a high-performance catalyst. Specifically, this invention relates to the preparation of ruthenium metal-supported nickel aluminate spinel, and the method for using ruthenium metal-supported nickel aluminate spinel to catalyze in-situ hydrogen production in an organic molecular hydrogen donor and an aqueous cosolvent, followed by hydrothermal liquefaction of a lignin derivative-containing solution to prepare bio-based chemicals. This process is mild, yields high-quality and selective bio-based chemicals, requires no external hydrogen source, and is highly efficient, green, and economical, providing a novel and sustainable method for the preparation of bio-based chemicals. In-situ hydrogen supply under mild reaction conditions promotes the development of the bio-based chemical industry, bioenergy, and biorefining industry.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) This invention provides a ruthenium metal-supported nickel aluminate spinel catalyst that changes the electron density of the original support and introduces Brønsted acid sites by wet impregnation of ruthenium metal onto the nickel aluminate support. The ruthenium metal works together with the Lewis acid sites and Brønsted acid sites to achieve regulation of the Lewis acid sites and Brønsted acid sites, thereby obtaining a ruthenium metal-supported nickel aluminate spinel catalyst with strong catalytic activity and stability.

[0040] (2) In the ruthenium metal-supported nickel aluminate spinel catalyst provided by the present invention, ruthenium metal is loaded onto the surface of the nickel aluminate support by a wet impregnation method. The characteristics of the bifunctional catalyst can be controlled by adjusting the amount of ruthenium metal loading to control the metal sites provided by zero-valent ruthenium and the Lewis acid sites provided by ruthenium oxide, thereby regulating the hydrogen donor to efficiently produce hydrogen and undergo hydrogen transfer on its surface, so as to achieve an ultra-high conversion rate of lignin derivatives.

[0041] (3) The ruthenium metal-supported nickel aluminate spinel catalyst of the present invention can be used to catalyze the catalytic transfer hydrogenation reaction of lignin derivatives. For example, it can be applied to catalyze the conversion of the substrate guaiacol under conditions of lower temperature and lower initial pressure, achieving a conversion rate of 95% and a cyclohexanol yield of 76%; and the target product (phenol, benzene, cyclohexanone, cyclohexane, 1-methyl-1,2-cyclohexanediol) can be selectively adjusted by controlling the reaction temperature, solvent ratio, initial pressure, and reaction time. Attached Figure Description

[0042] Figure 1 This is a flowchart of the method for preparing ruthenium metal-supported nickel aluminate spinel catalyst according to the present invention.

[0043] Figure 2 This is a TEM image of the ruthenium metal-supported nickel aluminate spinel catalyst in Example 2 of the present invention. Detailed Implementation

[0044] The following examples are used to further illustrate the present invention and are not intended to limit the invention.

[0045] Example 1

[0046] 5.8 g of [Ni(NO3)2]·6H2O was dissolved in 20 ml of ultrapure water to obtain solution ①; 15.05 g of [Al(NO3)3]·9H2O was dissolved in 30 ml of ultrapure water to obtain solution ②; solution ② was added to solution ①, and 50 mL of ultrapure water was added, and the mixture was stirred vigorously to ensure thorough mixing; ammonia solution (>25% in water) was added dropwise to the above metal salt solution while stirring until the pH reached 8; the precipitate was magnetically stirred at room temperature for 1 h and then allowed to stand for 10 h for aging; the solution was centrifuged to separate solid and liquid, and washed repeatedly with ultrapure water until the filtrate reached a neutral pH of 7; then dried in an oven at 100 °C for 10 h; the prepared sample was ground and sieved, and then calcined at 800 °C for 8 h under a nitrogen atmosphere to obtain nickel aluminate spinel support.

[0047] Dissolve 0.1026 g of hydrated ruthenium chloride in 5 mL of ultrapure water to obtain an aqueous solution of hydrated ruthenium chloride; add 0.5 g of nickel aluminate spinel powder to the solution and stir continuously for 12 h to obtain a solid suspension; evaporate the solid suspension by rotary evaporation and dry it in an oven at 80 °C for 12 h; calcine the obtained solid powder at 450 °C for 4 h under a nitrogen atmosphere, and then reduce it at 400 °C for 2 h under a 10% H2 / N2 atmosphere to obtain a ruthenium metal supported nickel aluminate spinel catalyst.

[0048] The application of ruthenium metal-supported nickel aluminate spinel catalyst in the preparation of bio-based chemicals from lignin derivatives in a co-solvent of water and organic molecular hydrogen donors is as follows: 0.08 g of ruthenium metal-supported nickel aluminate spinel catalyst, 0.167 g of guaiacol, 6 mL of water, and 4 mL of isopropanol were added to a hydrothermal reactor, 7 bar of Ar was introduced, and the mixture was stirred and heated to 200 °C for 2 h. After the reaction was completed, the mixture was cooled. The product obtained after cooling was centrifuged for solid-liquid separation, and the yield of cyclohexanol in the separated organic phase was analyzed by GC-MS and GC-FID, which showed to be approximately 19.64%.

[0049] Example 2

[0050] 19.85 g of [Ni(CH3COO)2]·4H2O was dissolved in 80 ml of ultrapure water to obtain solution ①; 60.2 g of [Al(NO3)3]·9H2O was dissolved in 120 ml of ultrapure water to obtain solution ②; solution ② was added to solution ①, and 200 mL of ultrapure water was added, and the mixture was stirred vigorously to ensure thorough mixing; ammonia solution (>25% in water) was added dropwise to the above metal salt solution while stirring until the pH reached 9; the precipitate was magnetically stirred at room temperature for 1 h and then allowed to stand for 12 h for aging; the solution was centrifuged to separate solid and liquid, and washed repeatedly with ultrapure water until the filtrate reached a neutral pH of 7; then dried in an oven at 100 °C for 12 h; the prepared sample was ground, sieved, and calcined at 800 °C for 8 h under a nitrogen atmosphere to obtain nickel aluminate spinel support.

[0051] Dissolve 0.3078 g of hydrated ruthenium chloride in 10 mL of ultrapure water to obtain an aqueous solution of hydrated ruthenium chloride; add 0.5 g of nickel aluminate spinel powder to the solution and stir continuously for 12 h to obtain a solid suspension; evaporate the solid suspension by rotary evaporation and dry it in an oven at 80 °C for 12 h; calcine the obtained solid powder at 450 °C for 4 h under a nitrogen atmosphere, and then reduce it at 400 °C for 3 h under a 10% H2 / N2 atmosphere to obtain a ruthenium metal supported nickel aluminate spinel catalyst.

[0052] The application of ruthenium metal-supported nickel aluminate spinel catalyst in the preparation of bio-based chemicals from lignin derivatives in a co-solvent of water and organic molecular hydrogen donors is as follows: 0.08 g of ruthenium metal-supported nickel aluminate spinel catalyst, 0.167 g of benzene, 6 mL of water, and 4 mL of isopropanol were added to a hydrothermal reactor, which was charged with 13 bar Ar, stirred, and heated to 200 °C for 2 h. After the reaction was completed, the mixture was cooled. The product obtained after cooling was centrifuged for solid-liquid separation, and the yield of cyclohexane in the separated organic phase was analyzed by GC-MS and GC-FID, which showed to be approximately 100%.

[0053] Example 3

[0054] 11.6 g of [Ni(NO3)2]·6H2O was dissolved in 40 ml of ultrapure water to obtain solution ①; 30.1 g of [Al(NO3)3]·9H2O was dissolved in 60 ml of ultrapure water to obtain solution ②; solution ② was added to solution ①, and 100 mL of ultrapure water was added, and the mixture was stirred vigorously to ensure thorough mixing; ammonia solution (>25% in water) was added dropwise to the above metal salt solution while stirring until the pH reached 8; the precipitate was magnetically stirred at room temperature for 1 h and then allowed to stand for 12 h for aging; the solution was centrifuged to separate solid and liquid, and washed repeatedly with ultrapure water until the filtrate reached a neutral pH of 7; then dried in an oven at 100 °C for 12 h; the prepared sample was ground and sieved, and then calcined at 800 °C for 8 h under a nitrogen atmosphere to obtain nickel aluminate spinel support.

[0055] Dissolve 0.3078 g of hydrated ruthenium chloride in 10 mL of ultrapure water to obtain an aqueous solution of hydrated ruthenium chloride; add 0.5 g of nickel aluminate spinel powder to the solution and stir continuously for 12 h to obtain a solid suspension; evaporate the solid suspension by rotary evaporation and dry it in an oven at 80 °C for 12 h; calcine the obtained solid powder at 450 °C for 4 h under a nitrogen atmosphere, and then reduce it at 400 °C for 3 h under a 10% H2 / N2 atmosphere to obtain a ruthenium metal supported nickel aluminate spinel catalyst.

[0056] The application of ruthenium metal-supported nickel aluminate spinel catalyst in the preparation of bio-based chemicals from lignin derivatives in a co-solvent of water and organic molecular hydrogen donors is as follows: 0.08 g of ruthenium metal-supported nickel aluminate spinel catalyst, 0.167 g of guaiacol, 9 mL of water, and 1 mL of isopropanol were added to a hydrothermal reactor, which was charged with 13 bar Ar, stirred, and heated to 200 °C for 3 h. After the reaction was completed, the mixture was cooled. The product obtained after cooling was centrifuged for solid-liquid separation, and the yield of cyclohexanol in the separated organic phase was analyzed by GC-MS and GC-FID, which showed to be approximately 36.99%.

[0057] Example 4

[0058] 23.2 g of [Ni(NO3)2]·6H2O was dissolved in 80 ml of ultrapure water to obtain solution ①; 60.2 g of [Al(NO3)3]·9H2O was dissolved in 120 ml of ultrapure water to obtain solution ②; solution ② was added to solution ①, and 200 mL of ultrapure water was added, and the mixture was stirred vigorously to ensure thorough mixing; ammonia solution (>25% in water) was added dropwise to the above metal salt solution while stirring until the pH reached 9; the precipitate was magnetically stirred at room temperature for 1 h and then allowed to stand for 12 h for aging; the solution was centrifuged to separate solid and liquid, and washed repeatedly with ultrapure water until the filtrate reached a neutral pH of 7; then dried in an oven at 100 °C for 12 h; the prepared sample was ground and sieved, and then calcined at 800 °C for 8 h under a nitrogen atmosphere to obtain nickel aluminate spinel support.

[0059] Dissolve 0.3078 g of hydrated ruthenium chloride in 10 mL of ultrapure water to obtain an aqueous solution of hydrated ruthenium chloride; add 0.5 g of nickel aluminate spinel powder to the solution and stir continuously for 12 h to obtain a solid suspension; evaporate the solid suspension by rotary evaporation and dry it in an oven at 80 °C for 12 h; calcine the obtained solid powder at 450 °C for 4 h under a nitrogen atmosphere, and then reduce it at 400 °C for 3 h under a 10% H2 / N2 atmosphere to obtain a ruthenium metal supported nickel aluminate spinel catalyst.

[0060] The application of ruthenium metal-supported nickel aluminate spinel catalyst in the preparation of bio-based chemicals from lignin derivatives in a co-solvent of water and organic molecular hydrogen donors is as follows: 0.08 g of ruthenium metal-supported nickel aluminate spinel catalyst, 0.167 g of cyclohexanone, 7 mL of water, and 3 mL of isopropanol were added to a hydrothermal reactor, which was charged with 13 bar of Ar, stirred, and heated to 200 °C for 3 h. After the reaction was completed, the mixture was cooled. The product obtained after cooling was centrifuged for solid-liquid separation, and the yield of cyclohexanol in the separated organic phase was analyzed by GC-MS and GC-FID, which showed to be approximately 82.80%.

[0061] Example 5

[0062] 23.2 g of [Ni(NO3)2]·6H2O was dissolved in 80 ml of ultrapure water to obtain solution ①; 60.2 g of [Al(NO3)3]·9H2O was dissolved in 120 ml of ultrapure water to obtain solution ②; solution ② was added to solution ①, and 200 mL of ultrapure water was added, and the mixture was stirred vigorously to ensure thorough mixing; ammonia solution (>25% in water) was added dropwise to the above metal salt solution while stirring until the pH reached 9; the precipitate was magnetically stirred at room temperature for 1 h and then allowed to stand for 12 h for aging; the solution was centrifuged to separate solid and liquid, and washed repeatedly with ultrapure water until the filtrate reached a neutral pH of 7; then dried in an oven at 100 °C for 12 h; the prepared sample was ground and sieved, and then calcined at 800 °C for 8 h under a nitrogen atmosphere to obtain nickel aluminate spinel support.

[0063] Dissolve 0.3078 g of hydrated ruthenium chloride in 10 mL of ultrapure water to obtain an aqueous solution of hydrated ruthenium chloride; add 0.5 g of nickel aluminate spinel powder to the solution and stir continuously for 12 h to obtain a solid suspension; evaporate the solid suspension by rotary evaporation and dry it in an oven at 80 °C for 12 h; calcine the obtained solid powder at 450 °C for 4 h under a nitrogen atmosphere, and then reduce it at 400 °C for 3 h under a 10% H2 / N2 atmosphere to obtain a ruthenium metal supported nickel aluminate spinel catalyst.

[0064] The application of ruthenium metal-supported nickel aluminate spinel catalyst in the preparation of bio-based chemicals from lignin derivatives in a co-solvent of water and organic molecular hydrogen donors is as follows: 0.08 g of ruthenium metal-supported nickel aluminate spinel catalyst, 0.17 g of 2-phenoxy-1-phenylethanol, 6 mL of water and 4 mL of isopropanol were added to a hydrothermal reactor, 13 bar of Ar was introduced, the mixture was stirred and heated to 200 °C for 3 h. After the reaction was completed, the mixture was cooled. The product obtained after cooling was centrifuged for solid-liquid separation, and the yield of cyclohexanol in the separated organic phase was analyzed by GC-MS and GC-FID, which showed to be approximately 78.11%.

[0065] Example 6

[0066] 23.2 g of [Ni(NO3)2]·6H2O was dissolved in 80 ml of ultrapure water to obtain solution ①; 60.2 g of [Al(NO3)3]·9H2O was dissolved in 120 ml of ultrapure water to obtain solution ②; solution ② was added to solution ①, and 200 mL of ultrapure water was added, and the mixture was stirred vigorously to ensure thorough mixing; ammonia solution (>25% in water) was added dropwise to the above metal salt solution while stirring until the pH reached 9; the precipitate was magnetically stirred at room temperature for 1 h and then allowed to stand for 12 h for aging; the solution was centrifuged to separate solid and liquid, and washed repeatedly with ultrapure water until the filtrate reached a neutral pH of 7; then dried in an oven at 100 °C for 12 h; the prepared sample was ground and sieved, and then calcined at 800 °C for 8 h under a nitrogen atmosphere to obtain nickel aluminate spinel support.

[0067] Dissolve 0.3078 g of hydrated ruthenium chloride in 10 mL of ultrapure water to obtain an aqueous solution of hydrated ruthenium chloride; add 0.5 g of nickel aluminate spinel powder to the solution and stir continuously for 12 h to obtain a solid suspension; evaporate the solid suspension by rotary evaporation and dry it in an oven at 80 °C for 12 h; calcine the obtained solid powder at 450 °C for 4 h under a nitrogen atmosphere, and then reduce it at 400 °C for 3 h under a 10% H2 / N2 atmosphere to obtain a ruthenium metal supported nickel aluminate spinel catalyst.

[0068] The application of ruthenium metal-supported nickel aluminate spinel catalyst in the preparation of bio-based chemicals from lignin derivatives in a co-solvent of water and organic molecular hydrogen donors is as follows: 0.08 g of ruthenium metal-supported nickel aluminate spinel catalyst, 0.17 g of 2,6-dimethoxyphenol, 6 mL of water and 4 mL of isopropanol were added to a hydrothermal reactor, 13 bar of Ar was introduced, the mixture was stirred and heated to 200 °C for 3 h. After the reaction was completed, the mixture was cooled. The product obtained after cooling was centrifuged for solid-liquid separation, and the yield of cyclohexanol in the separated organic phase was analyzed by GC-MS and GC-FID, which showed to be approximately 43.93%.

[0069] Example 7

[0070] 23.2 g of [Ni(NO3)2]·6H2O was dissolved in 80 ml of ultrapure water to obtain solution ①; 60.2 g of [Al(NO3)3]·9H2O was dissolved in 120 ml of ultrapure water to obtain solution ②; solution ② was added to solution ①, and 200 mL of ultrapure water was added, and the mixture was stirred vigorously to ensure thorough mixing; ammonia solution (>25% in water) was added dropwise to the above metal salt solution while stirring until the pH reached 9; the precipitate was magnetically stirred at room temperature for 1 h and then allowed to stand for 12 h for aging; the solution was centrifuged to separate solid and liquid, and washed repeatedly with ultrapure water until the filtrate reached a neutral pH of 7; then dried in an oven at 100 °C for 12 h; the prepared sample was ground and sieved, and then calcined at 800 °C for 8 h under a nitrogen atmosphere to obtain nickel aluminate spinel support.

[0071] Dissolve 0.3078 g of hydrated ruthenium chloride in 10 mL of ultrapure water to obtain an aqueous solution of hydrated ruthenium chloride; add 0.5 g of nickel aluminate spinel powder to the solution and stir continuously for 12 h to obtain a solid suspension; evaporate the solid suspension by rotary evaporation and dry it in an oven at 80 °C for 12 h; calcine the obtained solid powder at 450 °C for 4 h under a nitrogen atmosphere, and then reduce it at 400 °C for 3 h under a 10% H2 / N2 atmosphere to obtain a ruthenium metal supported nickel aluminate spinel catalyst.

[0072] The application of ruthenium metal-supported nickel aluminate spinel catalyst in the preparation of bio-based chemicals from lignin derivatives in a co-solvent of water and organic molecular hydrogen donors is as follows: 0.08 g of ruthenium metal-supported nickel aluminate spinel catalyst, 0.17 g of benzyl phenyl ether, 6 mL of water and 4 mL of isopropanol were added to a hydrothermal reactor, 13 bar of Ar was introduced, the mixture was stirred and heated to 200 °C for 3 h. After the reaction was completed, the mixture was cooled. The product obtained after cooling was centrifuged for solid-liquid separation, and the yield of cyclohexanol in the separated organic phase was analyzed by GC-MS and GC-FID, which showed to be approximately 85.26%.

Claims

1. The application of a ruthenium metal-supported nickel aluminate spinel catalyst in the preparation of bio-based chemicals, characterized in that: Using ruthenium-supported nickel aluminate spinel as a catalyst, bio-based chemicals are prepared by in-situ hydrogen production from organic molecules and an aqueous cosolvent, promoting the catalytic transfer hydrogenation of lignin derivatives. The specific steps are as follows: (A) A ruthenium metal-supported nickel aluminate spinel catalyst is added to a cosolvent consisting of water containing a lignin derivative and an organic molecular hydrogen donor to obtain a mixture; the mass ratio of ruthenium metal-supported nickel aluminate spinel to the lignin derivative is 0.06-0.6:1; wherein: the lignin derivative is any one of guaiacol, benzene, benzylphenyl ether, cyclohexanone, 2-phenoxy-1-phenylethanol, or 2,6-dimethoxyphenol; the organic molecular hydrogen donor is isopropanol; (B) Add the mixture obtained in step (A) into a hydrothermal reactor, pressurize it with argon gas, stir and heat it to a set temperature, and maintain the reaction at that temperature for a certain time; (C) After the reaction in step (B) is complete, cool down; (D) The product obtained after cooling in step (C) is subjected to centrifugation for solid-liquid separation and extraction to obtain an organic phase; (E) The organic solvent in the organic phase obtained in step (D) is removed by rotary evaporation to obtain the target product; One method for preparing a ruthenium metal-supported nickel aluminate spinel catalyst includes the following specific steps: (1) The precursors of nickel and aluminum are dissolved in ultrapure water in sequence at a Ni / Al molar ratio of 1 / 8-1 / 2, and the mixture is stirred vigorously to make it fully mixed to obtain a metal salt solution; (2) Add ammonia solution dropwise to the metal salt solution obtained in step (1) while stirring until the solution becomes alkaline and a uniform viscous paste-like liquid is obtained. (3) Stir the viscous paste-like liquid obtained in step (2) vigorously at room temperature and let it stand to age; (4) Centrifuge the layered paste liquid obtained in step (3) to separate the solid and liquid, and wash the solid precipitate with ultrapure water multiple times until the filtrate reaches neutrality; (5) The precipitate obtained in step (4) is placed in an oven to dry, and then ground and sieved; (6) Place the powder obtained in step (5) in a tube furnace, heat it to the set temperature under a nitrogen atmosphere and calcine it, then cool it to room temperature to obtain nickel aluminate spinel carrier. (7) Dissolve the ruthenium precursor in ultrapure water and stir until completely dissolved to obtain an aqueous solution of the ruthenium precursor; (8) Add the nickel aluminate spinel obtained in step (6) to the aqueous solution of the ruthenium precursor obtained in step (7) and stir continuously to obtain a solid suspension. Stir vigorously at room temperature. The mass ratio of ruthenium to nickel aluminate spinel is (0.005-0.2):

1. (9) The solid suspension obtained in step (8) is dried by rotary evaporation to obtain primary solid powder; (10) Place the primary solid powder obtained in step (9) in an oven to dry, cool to room temperature, grind and sieve to obtain secondary solid powder; (11) The secondary solid powder obtained in step (10) is placed in a tube furnace, heated to a set temperature under a nitrogen atmosphere and calcined, and then cooled to room temperature to obtain tertiary solid powder. (12) The tertiary solid powder obtained in step (11) is placed in a tube furnace and heated and reduced in a mixed atmosphere of hydrogen and nitrogen. After cooling to room temperature, ruthenium metal supported nickel aluminate spinel catalyst is obtained.

2. The application according to claim 1, characterized in that: In step (1), the precursor of nickel is any one of nickel hydrated nitrate, nickel hydrated acetate, or nickel hydrated chlorate; the precursor of aluminum is any one of aluminum hydrated nitrate, aluminum hydrated acetate, or aluminum hydrated chlorate; in step (7), the precursor of ruthenium is any one of ruthenium chloride, ruthenium oxide, ruthenium nitrate, ruthenium acetate, or ruthenium acetylacetonate.

3. The application according to claim 1, characterized in that: In step (6), the powder is calcined at 400-800℃ for 1-10h in a nitrogen atmosphere.

4. The application according to claim 1, characterized in that: The solid suspension obtained in step (8) is stirred vigorously at room temperature for 1-24 hours.

5. The application according to claim 1, characterized in that: The primary solid powder obtained in step (10) is dried in an oven at 50-100℃ for 4-12 hours.

6. The application according to claim 1, characterized in that: The secondary solid powder obtained in step (11) is heated to 100-800℃ under a nitrogen atmosphere and held for 0.5-5h.

7. The application according to claim 1, characterized in that: The tertiary solid powder obtained in step (12) is heated to 150-400℃ in a mixed atmosphere of hydrogen and nitrogen and held for 0.5-5h.

8. The application according to claim 1, characterized in that: In step (B), the mixture obtained in step (A) is added to a hydrothermal reactor, the reactor is sealed and evacuated, Ar at 0-20 bar is introduced, and the mixture is stirred and heated to any temperature between 100-300℃. The reaction is then maintained at this temperature for 0.5-5 h.

Images