Method for preparing ketone compounds by catalyzing cellulose hydrogenolysis with Pd / C supported catalyst

Abstract

The invention discloses a method for preparing ketone compounds by catalyzing cellulose hydrogenolysis with a Pd / C supported catalyst. The method comprises the following steps: by taking cellulose as a raw material, water as a solvent and active carbon supported Pd as a catalyst, reacting for 1-6 hours under the conditions that the total pressure of hydrogen source gas containing CO is 0.5-4.0 MPa and the temperature is 150-260 DEG C to obtain a product mainly containing ketone compounds; the CO-containing hydrogen source gas is mainly composed of hydrogen and CO, and the volume percentage content of CO is 3%-85%. The reaction provided by the invention has the characteristics of renewable resources of raw materials, low cost in the reaction process, environment friendliness, mild reaction conditions, high product selectivity, high added value and economic value of the product and the like, and an effective way for preparing the ketone compound from biomass is provided.

Description

Technical Field

[0001] The present invention relates to the preparation of ketone compounds, and particularly to a method for catalytically hydrogenolyzing cellulose to prepare ketone compounds by using a Pd / C supported catalyst. Background Art

[0002] As a widely existing renewable carbon resource, biomass is considered to be able to replace fossil resources for the preparation of liquid fuels and chemicals. Among biomass, cellulose is the main component, and its effective conversion is the key to biomass utilization. Cellulose is a polymer formed by the polymerization of glucose through glycosidic bonds. Depolymerizing it into platform molecules with small molecular weights and then converting them into other important chemicals is a feasible way for cellulose conversion.

[0003] The cellulose hydrogenation reaction mainly refers to the process of converting this polysaccharide cellulose into other useful chemical substances through a hydrogenation reaction, which belongs to the category of reduction reactions. Palladium (Pd) has been used as a catalyst in various catalytic hydrogenation reactions, but there are still two problems when it is used as a catalyst for catalytic hydrogenation reactions: on the one hand, due to the extremely strong hydrogenation performance of Pd, it will hydrogenate all functional groups without selectivity in compounds containing multiple hydrogenation functional groups (such as containing -C=C, -C≡C, -C=O, etc.). On the other hand, Pd is extremely easily poisoned by carbon monoxide (CO), which makes the purity requirement for the hydrogen used in the hydrogenation process very high, at least requiring the hydrogen purity to be higher than 99.99%.

[0004] At present, a large amount of high-purity hydrogen (purity higher than 99.99%) used in industry is mainly obtained by reforming reactions such as coal-to-hydrogen (including direct hydrogen production and indirect hydrogen production such as methanol cracking to produce hydrogen), biological hydrogen production, and hydrocarbon hydrogen production to obtain crude hydrogen, and then purifying CO in the crude hydrogen by pressure swing adsorption, membrane separation or cryogenic separation to obtain high-purity hydrogen. According to the report (NREL / SR-540-32525) of the National Renewable Energy Laboratory (NERL) of the US Department of Energy: Depending on the source of hydrogen, the fixed asset investment and daily operating cost required to purify hydrogen by pressure swing adsorption account for 10-20% of the total hydrogen production cost; it can be seen that the production cost of high-purity hydrogen is significantly higher than that of crude hydrogen; and the use of high-purity hydrogen increases the cost of catalytic hydrogenation reactions in industry.

[0005] Biomass-derived ketones are an important category of platform molecules and can be classified into cyclic ketones and linear ketones. Cyclic ketones are useful chemicals or intermediates for producing valuable chemicals. For example, 2-methylcyclopent-2-enone (MCPE) is a key intermediate for synthesizing specific flavors and fragrances used in perfumes, cosmetics, and foods. In recent years, linear diketones have received extensive research attention due to their inherent high value and great application potential. For example, 1-hydroxy-2-hexanone (HHO) and 2,5-hexanedione (HD) can be used to synthesize a series of high-end chemical products through chemical conversion for energy, food, medicine, and various other uses. HD is an important chemical for synthesizing pesticides and resin materials and can also be used to produce high-density aviation biofuels. HHO contains a hydroxyl group and an adjacent ketone group and is an important platform for generating various high-value-added chemicals and fuels. Generally, cellulose-derived ketones can be directly obtained from the depolymerization process of renewable cellulose through various domino reaction pathways. Hydrogenation is a key step in the traditional synthesis of cellulose-derived ketones. Therefore, efforts have been made to develop new and efficient catalytic hydrogenation systems for this reaction.

[0006] Chinese invention patent CN110922310B discloses a method for preparing hydroxybutanone from cellulose. The cellulose is placed in water and reacted under a hydrogen atmosphere and the action of a catalyst to obtain 1-hydroxy-2-butanone and 3-hydroxy-2-butanone. The catalyst consists of component A and component B; component A is a tungsten-based compound (the main active component), and component B is prepared by loading one or more of the transition metals of groups 8, 9, and 10, such as iron, cobalt, nickel, ruthenium, rhodium, palladium, iridium, and platinum, as the second metal component on one or more porous materials. Although this technology can obtain a relatively high yield of ketones, the reaction requires a large amount of high-purity hydrogen, resulting in high production costs and restricting the industrialization of the technology; moreover, currently, hydrogenation depolymerization of cellulose and even the entire biomass requires high-purity hydrogen.

[0007] Chinese invention patent CN110028393B discloses a method for catalytic hydrogenation of cellulose to prepare acetol and hydroxybutanone. Using cellulose as the raw material, Ni-W / C is used as the catalyst for aqueous-phase hydrogenation to prepare acetol and hydroxybutanone. The reaction temperature is 180 - 260 °C, and the hydrogen pressure in the reaction system is 1 - 5 MPa; the preparation method of the Ni-W / C catalyst is as follows: nickel salt, organic matter, ammonium tungstate or / and ammonium metatungstate, and deionized water are stirred at 70 °C for 6 - 12 hours; the temperature is raised to 100 - 160 °C and maintained for 12 hours, and the obtained powder sample is calcined in an inert atmosphere at 600 - 800 °C for 3 hours; the organic matter is selected from one or more of glucose, tartaric acid, sorbitol, citric acid, and malic acid. This technology also relies on high-purity hydrogen, which increases the difficulty of industrialization.

[0008] Chinese invention patent CN114057554B discloses a method for preparing 2,5 - hexanedione by hydrogenation of lignocellulose. This method uses lignocellulose as the raw material, an aqueous solution of liquid acid as the solvent, a graphene carbon nanotube / carbon shell - wrapped metal material as the catalyst, a hydrogen pressure of 1 - 6 MPa, and a reaction temperature of 180 - 260 °C. Although this method can obtain a relatively high yield of ketone compounds, due to the need for a large amount of high - purity hydrogen in the reaction, the production cost is relatively high. Moreover, using an aqueous solution of liquid acid as the solvent is likely to cause corrosion to the reaction equipment, posing higher requirements for the selection of equipment, and the reaction products are not easily separated, making it difficult to industrialize. Summary of the Invention

[0009] Aiming at the problems existing in the prior art, the present invention aims to provide a method for catalytic hydrogenolysis of cellulose to prepare ketone compounds using a Pd / C - supported catalyst with mild reaction conditions, environmental friendliness, and high catalytic efficiency, so as to enable catalytic hydrogenation reactions to be carried out using crude hydrogen, thereby significantly reducing the cost of catalytic hydrogenation reactions.

[0010] The object of the present invention is achieved through the following technical solutions:

[0011] A method for catalytic hydrogenolysis of cellulose to prepare ketone compounds using a Pd / C - supported catalyst: using cellulose as the raw material, water as the solvent, activated carbon - supported Pd as the catalyst, reacting at a total pressure of a hydrogen - containing gas source containing CO of 0.5 - 4.0 MPa and a temperature of 150 - 260 °C for 1 - 6 h to obtain a product mainly composed of ketone compounds; the hydrogen - containing gas source containing CO is mainly composed of hydrogen and CO, and the volume percentage content of CO is 3% - 85%; the Pd loading amount in the catalyst is 1 - 30 wt%.

[0012] To further achieve the object of the present invention, preferably, the Pd loading amount in the catalyst is 3 - 10 wt%

[0013] Preferably, the mass ratio of cellulose to the catalyst is 1:0.2 - 1:0.6, and the mass ratio of cellulose to water is 1:10 - 1:20.

[0014] Preferably, the volume percentage content of CO in the hydrogen - containing gas source containing CO is preferably 10 - 50%.

[0015] Preferably, the catalyst is prepared through the following steps:

[0016] 1) Dissolve the Pd - source precursor in a solvent, add ammonia water and water, and form solution A under stirring;

[0017] 2) Add water, alkali, and carbon black powder to solution A under stirring to form liquid B;

[0018] 3) Ultrasonically treat liquid B, add a reducing agent under an inert atmosphere and stirring, and heat to 20 - 90 °C for reaction for 0.5 - 6 h; subject the reaction product to suction filtration, washing, and vacuum drying to obtain the Pd / C catalyst; the reducing agent is at least one of NaBH 4 , vitamin C, and formaldehyde.

[0019] Preferably, in step 1, the Pd source precursor is selected from at least one of PdCl 2 , Na 2 PdCl 4 and K 2 PdCl 4 ; the solvent is HCl or ultrapure water; the molar volume concentration of the Pd source precursor in solution A is 1×10 -4 - 1×10 -1 mol / L; the molar ratio of the Pd source precursor to ammonia water is 1:10 - 50.

[0020] Preferably, in step 2, the base is at least one of NaOH and KOH; the molar volume concentration of the base in liquid B is 0.05 - 0.3 mol / L, and the volume - mass ratio of water to carbon black powder is 1:(0.1 - 30), with the volume unit being ml and the mass unit being mg.

[0021] Preferably, in step 3, the power of the ultrasonic treatment is 50 - 150 W, and the ultrasonic treatment time is 20 - 120 min; the magnetic stirring time is 5 - 240 min; the molar ratio of Pd to the reducing agent is 1:1 - 1000; the heating rate to 20 - 90 °C is 2 - 7 °C / min.

[0022] Preferably, the cellulose is microcrystalline cellulose and / or natural cellulose.

[0023] Preferably, the products mainly composed of ketone compounds include ketone compounds, alcohol compounds, and acid compounds.

[0024] Preferably, the ketone compounds are one or more of 1 - hydroxy - 2 - hexanone, 4 - hydroxy - 2 - hexanone, cyclopentanone, 3 - methylcyclopentanone, 2 - hydroxy - 3 - hexanone, 2 - methyl - 2 - cyclopenten - 1 - one, and 2,5 - hexanedione; the alcohol compounds are one or more of ethanol and 1,2 - hexanediol; the acid compounds are one or more of acetic acid, levulinic acid, and hexanoic acid

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] In the present invention, CO and water solvent react to undergo a water - gas shift reaction (CO + H2 O→H 2 +CO 2 ) can generate hydrogen. When the carbon-supported catalyst is applied to the catalytic hydrogenation reaction in the present invention, the volume percentage of CO contained in the hydrogen source gas used can be greater than 3.3%. Therefore, crude hydrogen with a higher CO content can be used for the catalytic hydrogenation reaction of cellulose, thereby reducing the cost of the cellulose catalytic reaction.

[0027] The reaction provided by the present invention has the characteristics of renewable raw materials, low reaction process cost, environmental friendliness, mild reaction conditions, high product selectivity, and high added value and economic value of the product, providing an effective way to prepare ketone compounds from biomass.

[0028] The present invention develops a novel hydrogenolysis strategy to replace the traditional hydrogenolysis technology and provides a method for realizing sustainable and cost-effective biomass utilization. Description of the Drawings

[0029] Figure 1 It is the SEM image of 5wt% Pd / C in Reaction Example 2.

[0030] Figure 2 is the TEM image of 5wt% Pd / C in Reaction Example 2 Figure 2a and particle size distribution diagram Figure 2b .

[0031] Figure 3 It is the FID spectrum of the product obtained by depolymerization of cellulose in Reaction Example 4.

[0032] Figure 4 It is the HPLC spectrum of the product obtained by depolymerization of cellulose in Reaction Example 4.

[0033] Figure 5 It is the FID spectrum of 1-hydroxy-2-hexanone, the product obtained by depolymerization of cellulose in Reaction Example 4.

[0034] Figure 6 It is the FID spectrum of 2,5-hexanedione, the product obtained by depolymerization of cellulose in Reaction Example 4.

[0035] Figure 7 It is the FID spectrum of 2-methyl-cyclopentene-1-one, the product obtained by depolymerization of cellulose in Reaction Example 4. Detailed Embodiments

[0036] To better understand the present invention, the present invention will be further described below in conjunction with the drawings and embodiments, but the embodiments of the present invention are not limited thereto.

[0037] The present invention mainly aims at the problem that high-purity hydrogen is required in the hydrocracking process of cellulose and even biomass. In current research and industry, high-purity hydrogen is required in all biomass hydrocracking processes, which greatly increases the industrial cost. Through the study of the hydrocracking reaction of cellulose under different reaction atmospheres, the present invention finds that when a Pd / C supported catalyst is used for catalytic hydrogenation reaction, the hydrogen source gas providing hydrogen elements for the catalytic hydrogenation reaction contains CO, and the volume percentage of CO can efficiently realize the preparation of ketone compounds by the hydrocracking of cellulose with a Pd / C supported catalyst within a very large range of 3% - 85%. Specifically, the method for preparing ketone compounds by the hydrocracking of cellulose with a Pd / C supported catalyst of the present invention: using cellulose as the raw material, water as the solvent, activated carbon supported Pd as the catalyst, reacting at a total pressure of 0.5 - 4.0 MPa and a temperature of 150 - 260 °C for 1 - 6 h in a hydrogen source gas containing CO to obtain a product mainly composed of ketone compounds; the hydrogen source gas containing CO is mainly composed of hydrogen and CO, and the volume percentage content of CO is 3% - 85%; the Pd loading in the catalyst is 1 - 30 wt%.

[0038] The present invention uses hydrogen containing CO (crude hydrogen) as the hydrogen source, and it is found that the hydrogen source containing CO not only has no negative impact on the reaction, but instead has a promoting effect on the reaction:

[0039] (1) CO can inhibit over-hydrogenation and prevent -C=O from being hydrogenated, thereby highly selectively producing high-value ketone compounds, and the ketone compounds mainly include 2,5 - hexanedione, 1 - hydroxy - 2 - hexanone, etc.

[0040] (2) The solvent of this reaction system is water, and CO in the reaction atmosphere will undergo a water-gas shift reaction (WGSR) with water to generate H 2 and CO 2 , and the generated CO 2 will continue to react with water at high temperature to generate H 2 CO 3 , H 2 CO 3 decomposes to generate H + to provide an acidic condition for the reaction and promote hydrolysis, thus generating ketone compounds.

[0041] The reaction raw material of the present invention is cellulose, and the hydrogen source gas containing CO directly or indirectly provides hydrogen species for the reaction. Cellulose first reacts under hydrothermal conditions to generate glucose, and glucose will undergo multiple reactions, including ring-opening to generate 1 - hydroxy - 2 - butanone (HB), hydrodeoxygenation reaction to generate 1 - hydroxy - 2 - hexanone (HHO), and isomerization to generate fructose. Fructose generates 5 - hydroxymethylfurfural (HMF) through dehydration, and then generates a series of products such as HD through a series of reactions such as hydrogenation and hydrolysis.

[0042] The preparation method of the Pd catalyst supported on activated carbon in the present invention adopts the liquid-phase chemical reduction method. Using ammonia water as a complexing agent, Pd ions first form stable complex ions in the liquid phase and then are reduced on the carbon powder through a reducing agent.

[0043] The reagents, materials, etc. used in the following examples are all common raw materials in the art and can be obtained commercially unless otherwise specified.

[0044] Example 1: Preparation of a Pd / C supported catalyst with a Pd content of 1.0 wt%:

[0045] 1. Add 0.02 g of PdCl 2 , add HCl to prepare a 0.1 M H 2 PdCl 4 solution, then add 5.0 mL of water. After stirring evenly, add 0.4 mL of ammonia water and stir magnetically until the solution becomes colorless and transparent; the molar volume concentration of H 2 PdCl 4 is 1.8×10 -2 M, and the molar ratio of H 2 PdCl 4 to ammonia water is 1:22;

[0046] 2. Add 30.0 mL of ultrapure water to the flask, then add 1.5 mL of 1.0 M NaOH solution and stir magnetically for 20.0 min;

[0047] 3. Add 0.9 g of carbon black powder to the flask, ultrasonicate at a power of 100 W for 30.0 min, then transfer the flask to an oil bath and stir magnetically for 2.0 h under an Ar gas atmosphere;

[0048] 4. Then, under magnetic stirring conditions, add 1 mL of formaldehyde solution to the flask and stir for 10.0 min; the molar ratio of Pd to formaldehyde is 1:115.5;

[0049] 5. Heat the above mixture at a heating rate of 2.0 °C / min to 60.0 °C and keep it at this temperature for a constant reaction for 2.0 h;

[0050] 6. Filter the obtained reaction product by suction, wash it 4 times with ultrapure water, and dry it in a vacuum drying oven at 80.0 °C for 4.0 h to obtain the Pd / C catalyst. It is detected that the mass fraction of Pd in the obtained catalyst is 1.0 wt%.

[0051] Example 2: Preparation of a Pd / C supported catalyst with a Pd content of 1.0 wt%:

[0052] 1. Add 0.02 g of Na2 PdCl 4 , add ultrapure water to prepare a 0.1 M Na 2 PdCl 4 solution, then add 5.0 mL of water. After stirring evenly, add 0.4 mL of ammonia water and stir magnetically until the solution becomes colorless and transparent; the molar volume concentration of Na 2 PdCl 4 is 1.8×10 -2 M, and the molar ratio of Na 2 PdCl 4 to ammonia water is 1:22;

[0053] 2. Add 30.0 mL of ultrapure water to the flask, then add 1.5 mL of 1.0 M NaOH solution and stir magnetically for 20.0 min;

[0054] 3. Add 0.9 g of carbon black powder to the flask, ultrasonicate at a power of 100 W for 30.0 min, then transfer the flask to an oil bath and stir magnetically for 2.0 h under an Ar atmosphere;

[0055] 4. Then, under magnetic stirring, add 1 mL of formaldehyde solution to the flask and stir for 10.0 min; the molar ratio of Pd to formaldehyde is 1:115.5;

[0056] 5. Heat the above mixture at a heating rate of 2.0 °C / min to 60.0 °C and keep it at this temperature for 2.0 h for the reaction;

[0057] 6. Filter the obtained reaction product by suction filtration, wash it 4 times with ultrapure water, and dry it at 80.0 °C in a vacuum drying oven for 4.0 h to obtain the Pd / C catalyst. The mass fraction of Pd in the obtained catalyst is 1.0 wt%.

[0058] Example 3: Preparation of a Pd / C supported catalyst with 1.0 wt% Pd content:

[0059] 1. Dissolve 0.02 g of K 2 PdCl 4 in ultrapure water to prepare a 0.1 M K 2 PdCl 4 solution, then add 5.0 mL of water. After stirring evenly, add 0.4 mL of ammonia water and stir magnetically until the solution becomes colorless and transparent; the molar volume concentration of K 2 PdCl 4 is 1.8×10 -2 M, and the molar ratio of K 2 PdCl 4 to ammonia water is 1:22;

[0060] 2. Add 30.0 mL of ultrapure water to the flask, then add 1.5 mL of 1.0 M NaOH solution, and stir magnetically for 20.0 min;

[0061] 3. Add 0.9 g of carbon black powder to the flask, sonicate at a power of 100 W for 30.0 min, then transfer the flask to an oil bath, and stir magnetically for 2.0 h under an Ar atmosphere;

[0062] 4. Then, under magnetic stirring conditions, add 1 mL of formaldehyde solution to the flask and stir for 10.0 min; the molar ratio of Pd to formaldehyde is 1:115.5;

[0063] 5. Heat the above mixture at a heating rate of 2.0 °C / min to 60.0 °C and maintain the temperature for 2.0 h for the reaction;

[0064] 6. Filter the obtained reaction product by suction filtration, wash it 4 times with ultrapure water, and dry it in a vacuum drying oven at 80.0 °C for 4.0 h to obtain the Pd / C catalyst. The mass fraction of Pd in the obtained catalyst is 1.0 wt%.

[0065] Example 4: Preparation of a Pd / C supported catalyst with a Pd content of 1.0 wt%:

[0066] 1. Dissolve 0.02 g of K 2 PdCl 4 in ultrapure water to prepare a 0.1 M K 2 PdCl 4 solution, then add 5.0 mL of water. After stirring evenly, add 0.4 mL of ammonia water and stir magnetically until the solution becomes colorless and transparent; the molar volume concentration of K 2 PdCl 4 in the solution is 1.8×10 -2 M, and the molar ratio of K 2 PdCl 4 to ammonia water is 1:22;

[0067] 2. Add 30.0 mL of ultrapure water to the flask, then add 1.5 mL of 1.0 M NaOH solution, and stir magnetically for 20.0 min;

[0068] 3. Add 0.9 g of carbon black powder to the flask, sonicate at a power of 50 W for 120.0 min, then transfer the flask to an oil bath, and stir magnetically for 1.0 h under an Ar atmosphere;

[0069] 4. Then, under magnetic stirring conditions, add 10 mL of 0.1 M KBH 4 solution to the flask and stir for 10.0 min; the molar ratio of Pd to KBH 4 is 1:8.4;

[0070] 5. Heat the above-mentioned mixed solution at a heating rate of 4.0 °C / min to 20.0 °C and keep it reacting at this temperature for 6.0 h.

[0071] 6. Filter the obtained reaction product by suction, wash it 4 times with ultrapure water, and dry it at 80.0 °C for 4.0 h in a vacuum drying oven to obtain the Pd / C catalyst. The mass fraction of Pd in the obtained catalyst is 1.0 wt%.

[0072] Example 5: Preparation of a Pd / C supported catalyst with a Pd content of 5.0 wt%:

[0073] 1. Weigh 0.02 g of PdCl 2 into a flask, add HCl to prepare a 0.1 M H 2 PdCl 4 solution, then add 5.0 mL of water. After stirring evenly, add 0.4 mL of ammonia water and stir magnetically until the solution becomes colorless and transparent; the molar volume concentration of H 2 PdCl 4 in the solution is 1.8×10 -2 M, and the molar ratio of H 2 PdCl 4 to ammonia water is 1:22.

[0074] 2. Add 30.0 mL of ultrapure water to the flask, then add 1.5 mL of 1.0 M NaOH solution and stir magnetically for 20.0 min.

[0075] 3. Add 0.2 g of carbon black powder to the flask, ultrasonicate it at a power of 100 W for 30.0 min, then transfer the flask to an oil bath and stir magnetically for 2.0 h under an Ar gas atmosphere.

[0076] 4. Then, under magnetic stirring conditions, add 1 mL of formaldehyde solution to the flask and stir for 10.0 min; the molar ratio of Pd to formaldehyde is 1:115.5.

[0077] 5. Heat the above-mentioned mixed solution at a heating rate of 7.0 °C / min to 90.0 °C and keep it reacting at this temperature for 0.5 h.

[0078] 6. Filter the obtained reaction product by suction, wash it 4 times with ultrapure water, and dry it at 80.0 °C for 4.0 h in a vacuum drying oven to obtain the Pd / C catalyst. As Figure 1 shown, the Pd / C catalyst has a rough and irregular morphology. As shown in Figure 2, Pd is well dispersed in the carbon black and has a uniform particle size. The mass fraction of Pd in the obtained catalyst is 5.0 wt%, and the Pd particle size is about 8.0 nm.

[0079] Example 6: Preparation of Pd / C supported catalyst with 5.0 wt% Pd content:

[0080] 1. Weigh 0.1 g of PdCl 2 into a flask, add HCl to prepare a 0.1 M H 2 PdCl 4 solution, then add 25.0 mL of water. After stirring evenly, add 2 mL of ammonia water and stir magnetically until the solution becomes colorless and transparent; the molar volume concentration of H 2 PdCl 4 in the solution is 1.8×10 -2 M, and the molar ratio of H 2 PdCl 4 to ammonia water is 1:22;

[0081] 2. Add 150.0 mL of ultrapure water to the flask, then add 7.5 mL of 1.0 M NaOH solution and stir magnetically for 20.0 min;

[0082] 3. Add 1.0 g of carbon black powder to the flask, ultrasonicate at a power of 150 W for 5.0 min, then transfer the flask to an oil bath and stir magnetically for 4.0 h under an Ar gas atmosphere;

[0083] 4. Then, under magnetic stirring conditions, add 5 mL of formaldehyde solution to the flask and stir for 10.0 min; the molar ratio of Pd to formaldehyde is 1:115.5;

[0084] 5. Heat the above mixture at a heating rate of 4.0 °C / min to 20.0 °C and keep it at this temperature for a constant reaction for 6.0 h;

[0085] 6. Filter the obtained reaction product by suction filtration, wash it 4 times with ultrapure water, and dry it in a vacuum drying oven at 80.0 °C for 4.0 h to obtain the Pd / C catalyst. As Figure 1 shown, the Pd / C catalyst has a rough and irregular morphology. As shown in Figure 2, Pd is well dispersed in the carbon black and has a uniform particle size. After testing, the mass fraction of Pd in the obtained catalyst is 5.0 wt%, and the Pd particle size is about 8.0 nm.

[0086] Example 7: Preparation of Pd / C supported catalyst with 30.0 wt% Pd content:

[0087] 1. Weigh 0.02 g of PdCl 2 into a flask, add HCl to prepare a 0.1 M H 2 PdCl 4A solution, then add 5.0 mL of water. After stirring evenly, add 0.4 mL of ammonia water and stir magnetically until the solution becomes colorless and transparent; in the said solution, the molar volume concentration of H 2 PdCl 4 is 1.8×10 -2 mol / L, and the molar ratio of H 2 PdCl 4 to ammonia water is 1:22;

[0088] 2. Add 30.0 mL of ultrapure water to the flask, then add 1.5 mL of 1.0 M NaOH solution and stir magnetically for 20.0 min;

[0089] 3. Add 400 mg of carbon black powder to the flask, ultrasonicate at a power of 100 W for 30.0 min, then transfer the flask to an oil bath and stir magnetically for 2.0 h under an Ar gas atmosphere;

[0090] 4. Then, under magnetic stirring conditions, add 26.5 mL of formaldehyde solution to the flask and stir for 10.0 min; the molar ratio of Pd to formaldehyde is 1:115.5;

[0091] 5. Heat the above mixture at a heating rate of 2.0 °C / min to 60.0 °C and keep the temperature constant at this temperature for 2.0 h;

[0092] 6. Filter the obtained reaction product by suction, wash it 4 times with ultrapure water, and dry it in a vacuum drying oven at 80.0 °C for 4.0 h to obtain the Pd / C catalyst. After detection, the mass fraction of Pd in the obtained catalyst is 30.0 wt%.

[0093] Example 8: Method for catalytically preparing ketone compounds from cellulose selectively in an H 2 / CO (1.5 / 1.5 MPa) atmosphere:

[0094] Dry the cellulose, take 0.5 g of cellulose, 0.2 g of 5.0 wt% Pd / C catalyst, and 20.0 mL of aqueous solution and add them to a 50.0 mL high-pressure reactor for mixing. The reactor is purged three times with high-purity argon, and then filled with 3.0 MPa of H 2 / CO (1.5 / 1.5 MPa) heated the autoclave to 230.0 °C and reacted for 2.0 h. After the reaction, the autoclave was cooled to room temperature. The reaction mixture was filtered, and then the volatile products were extracted and enriched with dichloromethane (DCM) (5.0 mL × 5 times) to obtain the aqueous phase and the dichloromethane phase. The residue was washed five times with tetrahydrofuran (5.0 mL × 5 times) and then dried in vacuo at 60.0 °C for 12.0 h. The cellulose conversion was calculated by weighing. The aqueous phase (containing water-soluble products such as acids and alcohols) was distilled under reduced pressure at 45.0 °C to remove methanol, collected, and diluted to 50.0 mL with ultrapure water. The aqueous phase products were qualitatively analyzed by high performance liquid chromatography-mass spectrometry (HPLC-MS). The chromatographic column was an HPX-87H sugar column (300 mm × 7.8 mm, 5 μm), with a refractive index detector (RID), detector temperature 50.0 °C, and the mobile phase was 5.0 mM H 2 SO 4 , flow rate 0.6 mL min -1 , column temperature 65.0 °C.

[0095] The components were quantitatively analyzed by the calibration curve method. The dichloromethane phase (containing volatile products such as ketones) was added with dimethyl phthalate (internal standard) and diluted to 25.0 mL with dichloromethane. It was qualitatively analyzed by gas chromatography-mass spectrometry (GC-MS) and quantitatively determined by GC. The chromatographic column was an HP-5MS 5% phenyl methyl silox capillary column (30 m × 0.25 μm × 0.25 μm), inlet temperature 270.0 °C, flame ionization detector (FID), detector temperature 270.0 °C, carrier gas He, flow rate 1.0 mL min -1 , the column temperature was a temperature programming, initial oven temperature 50.0 °C (maintained for 3.0 min), with a heating rate of 15.0 °C min -1 to 270.0 °C (held for 1 min). During the operation, the auxiliary temperature was maintained at 280.0 °C, split ratio 10:1. For qualitative analysis, the GC-FID chromatogram of the reaction solution is shown in Figure 3 , the chromatogram of liquid chromatography is shown in Figure 4 . Among them, the main products are ketone compounds. By analysis and detection, two types of products, ketone compounds and alcohols, appear at different retention times. Among them, 1-hydroxy-2-hexanone, 2,5-hexanedione, and 2-methyl-2-cyclopenten-1-one with the largest peak area are the main products. The chromatograms of these main products are shown in Figure 5 , Figure 6 , Figure 7 .

[0096] The cellulose conversion rate Conversion (%) is calculated based on the dry weight of the remaining solid, as shown in Equation 1. The carbon yield (%) of the liquid product is calculated by Equation 2, and the selectivity of the liquid product is calculated by Equation 3.

[0097]

[0098] Among them, m 1 is the mass of the original cellulose, and m 2 is the mass of the unreacted raw materials collected by filtration, washing, and drying. i refers to a certain product, and n i is the molar amount of product i, and k i is the number of carbon atoms in product i, and m cellulose is the weight of the initial cellulose. is the relative molecular mass of the glucose unit, and carbon yield i is the carbon yield of product i, and Conversion cellulose is the conversion rate of cellulose. i refers to a specific product. For example, when i refers to 2,5 - hexanedione, then n i is the molar amount of 2,5 - hexanedione, and k i is the number of carbon atoms in 2,5 - hexanedione.

[0099] After testing, under the action of the Pd / C catalyst, the unreacted raw materials (m 2 ) are 0.05 g. Using the calculation method of the remaining solid dry weight (Equation 1):

[0100]

[0101] The conversion rate of cellulose is obtained as 90.0%. Using the yield formula 2 of the liquid product for calculation, such as the yields of 1 - hydroxy - 2 - hexanone and 2,5 - hexanedione are calculated by the calculation method (Equation 2):

[0102] For 1 - hydroxy - 2 - hexanone

[0103] For 2,5 - hexanedione

[0104] The yields of 4-hydroxy-2-hexanone, cyclopentanone, 3-methylcyclopentanone, 2-hydroxy-3-hexanone, and 2-methyl-2-cyclopenten-1-one were calculated in the same way to be 3.6%, 7.2%, 3.4%, and 2.8% respectively. From this, the total yield of the product ketones was 37.8%. The product selectivity of the ketone compounds was calculated by formula 3 to be 42.0%. Other products were mainly alcohols (ethanol, 1,2-hexanediol) and acids (acetic acid, levulinic acid, and hexanoic acid). The yields and selectivities of the alcohol compounds were 20.1% and 22.3% respectively, and the yields and selectivities of the acid compounds were 7.9% and 8.7% respectively. The total yields and selectivities of the ketone, alcohol, and acid products were 65.8% and 73.1% respectively. The reaction results are listed in Table 1.

[0105] Example 9: Method for Catalyzing Cellulose with 5.0 wt% Pd / C in H 2 / CO (2.5 / 0.5 MPa) Atmosphere:

[0106] In this example, the steps of the Pd / C-catalyzed cellulose hydrocracking and depolymerization process were the same as those in Example 4, except that the reaction atmosphere was replaced with H 2 / CO = 2.5 / 0.5 MPa. Cellulose (0.5 g), 5.0 wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0107] After testing, the cellulose conversion rate under this reaction condition was 82.9%. The yields and selectivities of the product ketone compounds were 20.9% and 25.2% respectively. Other products were mainly alcohols and acids. The yields and selectivities of the alcohol compounds were 25.3% and 30.5% respectively, and the yields and selectivities of the acid compounds were 8.1% and 9.8% respectively. The total yields and selectivities of the ketone, alcohol, and acid products were 54.3% and 65.5% respectively. The reaction results are listed in Table 1.

[0108] Example 10: Method for Catalyzing Cellulose with 5.0 wt% Pd / C in H 2 / CO (2.0 / 1.0 MPa) Atmosphere:

[0109] In this example, the steps of the Pd / C-catalyzed cellulose hydrocracking and depolymerization process were the same as those in Example 4, except that the reaction atmosphere was replaced with H 2 / CO = 2.0 / 1.0 MPa. Cellulose (0.5 g), 5.0 wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0110] After testing, the cellulose conversion rate under this reaction condition was 87.8%, the yields and selectivities of the main product ketone compounds were 32.4% and 36.9% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 22.1% and 25.2% respectively, the yields and selectivities of the acid compounds were 8.1% and 9.2% respectively, and the total yields and selectivities of the ketone, alcohol and acid products were 62.6% and 71.3% respectively. The reaction results are shown in Table 1.

[0111] Example 11: Method for catalytically hydrogenating cellulose with 5.0 wt% Pd / C in H 2 / CO (1.0 / 2.0 MPa) atmosphere:

[0112] In this example, the steps of the Pd / C-catalyzed hydrogenolysis of cellulose were the same as those in Example 4, except that the reaction atmosphere was replaced with H 2 / CO = 1.0 / 2.0 MPa. Cellulose (0.5 g), 5.0 wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0113] After testing, the cellulose conversion rate under this reaction condition was 87.7%, the yields and selectivities of the main product ketone compounds were 26.6% and 30.3% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 17.6% and 20.0% respectively, the yields and selectivities of the acid compounds were 7.1% and 8.1% respectively, and the total yields and selectivities of the ketone, alcohol and acid products were 51.3% and 58.5% respectively. The reaction results are shown in Table 1.

[0114] Example 12: Method for catalytically hydrogenating cellulose with 5.0 wt% Pd / C in H 2 / CO (0.5 / 2.5 MPa) atmosphere:

[0115] In this example, the steps of the Pd / C-catalyzed hydrogenolysis of cellulose were the same as those in Example 4, except that the reaction atmosphere was replaced with H 2 / CO = 0.5 / 2.5 MPa. Cellulose (0.5 g), 5.0 wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0116] After testing, the cellulose conversion rate under this reaction condition was 84.2%, the yields and selectivities of the main product ketone compounds were 18.4% and 21.9% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 14.6% and 17.3% respectively, the yields and selectivities of the acid compounds were 6.5% and 7.7% respectively, and the total yields and selectivities of the ketone, alcohol and acid products were 39.5% and 46.9% respectively. The reaction results are shown in Table 1.

[0117] Example 13: Method for catalyzing cellulose by 1.0 wt% Pd / C in H 2 / CO (2.5 / 0.5 MPa) atmosphere:

[0118] In this example, the steps of the Pd / C-catalyzed cellulose hydrodepolymerization process were the same as those in Example 4, except that the reaction atmosphere was replaced with 3.0 MPa of H 2 / CO (2.5 / 0.5 MPa), and the catalyst was replaced with 1.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0119] After testing, the cellulose conversion rate under this reaction condition was 46.3%, the yields and selectivities of the product ketone compounds were 7.0% and 15.1% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 12.9% and 27.9% respectively, the yields and selectivities of the acid compounds were 1.4% and 3.0% respectively, and the total yields and selectivities of the ketone, alcohol and acid products were 21.3% and 46.0% respectively. The reaction results are shown in Table 1.

[0120] Example 14: Method for catalyzing cellulose by 1.0 wt% Pd / C in H 2 / CO (2.0 / 1.0 MPa) atmosphere:

[0121] In this example, the steps of the Pd / C-catalyzed cellulose hydrodepolymerization process were the same as those in Example 4, except that the reaction atmosphere was replaced with 3.0 MPa of H 2 / CO (2.0 / 1.0 MPa), and the catalyst was replaced with 1.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0122] After testing, the conversion rate of cellulose under this reaction condition was 46.2%, the yields and selectivities of the product ketone compounds were 13.0% and 28.1% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 10.7% and 23.2% respectively, the yields and selectivities of the acid compounds were 1.2% and 2.6% respectively, the total yields and selectivities of the ketone, alcohol and acid products were 24.9% and 54.9% respectively, and the reaction results are shown in Table 1.

[0123] Example 15: Method for catalyzing cellulose by 1.0 wt% Pd / C in H 2 / CO (1.5 / 1.5 MPa) atmosphere:

[0124] In this example, the steps of the Pd / C-catalyzed hydrodepolymerization process of cellulose were the same as those in Example 4, except that the reaction atmosphere was replaced with H 2 / CO (1.5 / 1.5 MPa) at 3.0 MPa, and the catalyst was replaced with 1.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g) and deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0125] After testing, the conversion rate of cellulose under this reaction condition was 41.1%, the yields and selectivities of the product ketone compounds were 8.8% and 21.4% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 7.9% and 19.2% respectively, the yields and selectivities of the acid compounds were 1.2% and 2.9% respectively, the total yields and selectivities of the ketone, alcohol and acid products were 17.9% and 43.6% respectively, and the reaction results are shown in Table 1.

[0126] Example 16: Method for catalyzing cellulose by 1.0 wt% Pd / C in H 2 / CO (1.0 / 2.0 MPa) atmosphere:

[0127] In this example, the steps of the Pd / C-catalyzed hydrodepolymerization process of cellulose were the same as those in Example 4, except that the reaction atmosphere was replaced with H 2 / CO (1.0 / 2.0 MPa) at 3.0 MPa, and the catalyst was replaced with 1.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g) and deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0128] After testing, the conversion rate of cellulose under this reaction condition was 34.3%, and the yields and selectivities of the product ketone compounds were 5.6% and 16.3% respectively. The other products were mainly alcohols and acids. The yields and selectivities of the alcohol compounds were 5.4% and 15.7% respectively, and the yields and selectivities of the acid compounds were 0.7% and 2.0% respectively. The total yields and selectivities of the ketone, alcohol and acid products were 11.7% and 34.1% respectively. The reaction results are shown in Table 1.

[0129] Example 17: Method for catalyzing cellulose by 1.0 wt% Pd / C in H 2 / CO (0.5 / 2.5 MPa) atmosphere:

[0130] In this example, the steps of the Pd / C-catalyzed hydrogenolysis and depolymerization process of cellulose were the same as those in Example 4, except that the reaction atmosphere was replaced with H 2 / CO (0.5 / 2.5 MPa) at 3.0 MPa, and the catalyst was replaced with 1.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g) and deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0131] After testing, the conversion rate of cellulose under this reaction condition was 28.9%, and the yields and selectivities of the product ketone compounds were 3.5% and 12.1% respectively. The other products were mainly alcohols and acids. The yields and selectivities of the alcohol compounds were 4.4% and 15.2% respectively, and the yields and selectivities of the acid compounds were 0.8% and 2.8% respectively. The total yields and selectivities of the ketone, alcohol and acid products were 8.7% and 30.1% respectively. The reaction results are shown in Table 1.

[0132] Example 18: Method for catalyzing cellulose by 30.0 wt% Pd / C in H 2 / CO (2.5 / 0.5 MPa) atmosphere:

[0133] In this example, the steps of the Pd / C-catalyzed hydrogenolysis and depolymerization process of cellulose were the same as those in Example 4, except that the reaction atmosphere was replaced with H 2 / CO (2.5 / 0.5 MPa) at 3.0 MPa, and the catalyst was replaced with 30.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g) and deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0134] After testing, the conversion rate of cellulose under this reaction condition was 90.7%, and the yields and selectivities of the product ketone compounds were 11.4% and 12.6% respectively. The other products were mainly alcohols and acid products. The yields and selectivities of the alcohol compounds were 47.2% and 52.0% respectively, and the yields and selectivities of the acid compounds were 5.1% and 5.6% respectively. The total yields and selectivities of the ketone, alcohol and acid products were 63.7% and 70.2% respectively. The reaction results are shown in Table 1.

[0135] Example 19: Method for catalyzing cellulose by 30.0 wt% Pd / C in H 2 / CO (2.0 / 1.0 MPa) atmosphere:

[0136] In this example, the steps of the Pd / C-catalyzed hydrogenolysis and depolymerization process of cellulose were the same as those in Example 4, except that the reaction atmosphere was replaced with 3.0 MPa of H 2 / CO (2.0 / 1.0 MPa), and the catalyst was replaced with 30.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0137] After testing, the conversion rate of cellulose under this reaction condition was 92.8%, and the yields and selectivities of the product ketone compounds were 23.7% and 25.5% respectively. The other products were mainly alcohols and acid products. The yields and selectivities of the alcohol compounds were 34.9% and 37.6% respectively, and the yields and selectivities of the acid compounds were 4.2% and 4.5% respectively. The total yields and selectivities of the ketone, alcohol and acid products were 62.8% and 67.7% respectively. The reaction results are shown in Table 1.

[0138] Example 20: Method for catalyzing cellulose by 30.0 wt% Pd / C in H 2 / CO (1.5 / 1.5 MPa) atmosphere:

[0139] In this example, the steps of the Pd / C-catalyzed hydrogenolysis and depolymerization process of cellulose were the same as those in Example 4, except that the reaction atmosphere was replaced with 3.0 MPa of H 2 / CO (1.5 / 1.5 MPa), and the catalyst was replaced with 30.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0140] After testing, the cellulose conversion rate under this reaction condition was 93.6%, and the yields and selectivities of the product ketone compounds were 33.2% and 35.5% respectively. The other products were mainly alcohols and acid products. The yields and selectivities of the alcohol compounds were 28.7% and 30.7% respectively, and the yields and selectivities of the acid compounds were 3.7% and 4.0% respectively. The total yields and selectivities of the ketone, alcohol and acid products were 65.6% and 70.1% respectively. The reaction results are shown in Table 1.

[0141] Example 21: Method for catalyzing cellulose by 30.0 wt% Pd / C in H 2 / CO (1.0 / 2.0 MPa) atmosphere:

[0142] In this example, the steps of the Pd / C-catalyzed cellulose hydrodepolymerization process were the same as those in Example 4, except that the reaction atmosphere was replaced with 3.0 MPa of H 2 / CO (1.0 / 2.0 MPa), and the catalyst was replaced with 30.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0143] After testing, the cellulose conversion rate under this reaction condition was 93.1%, and the yields and selectivities of the product ketone compounds were 35.6% and 38.2% respectively. The other products were mainly alcohols and acid products. The yields and selectivities of the alcohol compounds were 23.1% and 24.8% respectively, and the yields and selectivities of the acid compounds were 3.2% and 3.4% respectively. The total yields and selectivities of the ketone, alcohol and acid products were 61.9% and 66.5% respectively. The reaction results are shown in Table 1.

[0144] Example 22: Method for catalyzing cellulose by 30.0 wt% Pd / C in H 2 / CO (0.5 / 2.5 MPa) atmosphere:

[0145] In this example, the steps of the Pd / C-catalyzed cellulose hydrodepolymerization process were the same as those in Example 4, except that the reaction atmosphere was replaced with 3.0 MPa of H 2 / CO (0.5 / 2.5 MPa), and the catalyst was replaced with 30.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0146] After testing, the cellulose conversion rate under this reaction condition was 90.2%, the yields and selectivities of the product ketone compounds were 34.3% and 38.0% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 20.8% and 23.1% respectively, the yields and selectivities of the acid compounds were 3.5% and 3.9% respectively, the total yields and selectivities of the ketone, alcohol and acid products were 58.6% and 65.0% respectively, and the reaction results are shown in Table 1.

[0147] Comparative Example 1

[0148] In this comparative example, the reaction atmosphere did not use the mixed gas, only high-purity hydrogen was used.

[0149] This comparative example used 5.0 wt% Pd / C to catalyze cellulose in a pure H 2 atmosphere by the following method:

[0150] In this comparative example, the steps of the Pd / C-catalyzed hydrogenolysis and depolymerization process of cellulose were the same as those in Example 4, except that the reaction atmosphere was replaced with pure H at 3.0 MPa 2 . Cellulose (0.5 g), 5.0 wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0151] After testing, the cellulose conversion rate under this reaction condition was 75.9%, the yields and selectivities of the product ketone compounds were 5.6% and 7.4% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 41.8% and 55.1% respectively, the yields and selectivities of the acid compounds were 9.0% and 11.9% respectively, the total yields and selectivities of the ketone, alcohol and acid products were 56.4% and 74.3% respectively, and the reaction results are shown in Table 1.

[0152] Comparative Example 2

[0153] In this comparative example, the reaction atmosphere did not use the mixed gas, only high-purity CO was used.

[0154] This comparative example used 5.0 wt% Pd / C to catalyze cellulose in a high-purity CO atmosphere by the following method:

[0155] In this comparative example, the steps of the Pd / C-catalyzed hydrogenolysis and depolymerization process of cellulose were the same as those in Example 4, except that the reaction atmosphere was replaced with pure CO at 3.0 MPa. Cellulose (0.5 g), 5.0 wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0156] After testing, the cellulose conversion rate under this reaction condition was 48.9%, the yields and selectivities of the product ketone compounds were 4.6% and 9.4% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 9.2% and 18.8% respectively, the yields and selectivities of the acid compounds were 5.4% and 11.0% respectively, and the total yields and selectivities of the ketone, alcohol and acid products were 19.2% and 39.3% respectively. The reaction results are shown in Table 1.

[0157] Comparative Example 3

[0158] In this comparative example, the reaction atmosphere did not use a mixed gas, only high-purity hydrogen was used.

[0159] This comparative example used 1.0 wt% Pd / C to catalyze cellulose in a pure H 2 atmosphere:

[0160] In this comparative example, the steps of the Pd / C-catalyzed hydrodepolymerization process of cellulose were the same as those in Example 4, except that the reaction atmosphere was replaced with pure H at 3.0 MPa 2 , and the catalyst was replaced with a 1.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0161] After testing, the cellulose conversion rate under this reaction condition was 32.3%, no ketone compounds were detected, the yields and selectivities of the alcohol compounds were 14.4% and 44.6% respectively, the yields and selectivities of the acid compounds were 1.7% and 5.3% respectively, and the total yields and selectivities of the ketone, alcohol and acid products were 16.1% and 49.8% respectively. The reaction results are shown in Table 1.

[0162] Comparative Example 4

[0163] In this comparative example, the reaction atmosphere did not use a mixed gas, only high-purity CO was used.

[0164] This comparative example used 1.0 wt% Pd / C to catalyze cellulose in a pure CO atmosphere:

[0165] In this comparative example, the steps of the Pd / C-catalyzed hydrodepolymerization process of cellulose were the same as those in Example 4, except that the reaction atmosphere was replaced with pure CO at 3.0 MPa, and the catalyst was replaced with a 1.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0166] After testing, the conversion rate of cellulose under this reaction condition was 22.6%, the yields and selectivities of the product ketone compounds were 0.9% and 4.0% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 3.1% and 13.7% respectively, the yields and selectivities of the acid compounds were 0.7% and 3.1% respectively, the total yields and selectivities of the ketone, alcohol and acid products were 4.7% and 20.8% respectively, and the reaction results are shown in Table 1.

[0167] Comparative Example 5

[0168] In this comparative example, the reaction atmosphere did not use a mixed gas, and only high-purity hydrogen was used.

[0169] The method for catalyzing cellulose using 30.0 wt% Pd / C under pure H 2 atmosphere:

[0170] In this comparative example, the steps of the Pd / C-catalyzed hydrogenolysis and depolymerization process of cellulose were the same as those in Example 4, except that the reaction atmosphere was replaced with pure H at 3.0 MPa 2 , and the catalyst was replaced with a 30.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0171] After testing, the conversion rate of cellulose under this reaction condition was 84.5%, the yields and selectivities of the product ketone compounds were 1.1% and 1.3% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 53.1% and 62.8% respectively, the yields and selectivities of the acid compounds were 5.7% and 6.7% respectively, the total yields and selectivities of the ketone, alcohol and acid products were 59.9% and 70.9% respectively, and the reaction results are shown in Table 1.

[0172] Comparative Example 6

[0173] In this comparative example, the reaction atmosphere did not use a mixed gas, and only high-purity CO was used.

[0174] The method for catalyzing cellulose using 30.0 wt% Pd / C under pure CO atmosphere:

[0175] In this comparative example, the steps of the Pd / C-catalyzed hydrogenolysis and depolymerization process of cellulose were the same as those in Example 4, except that the reaction atmosphere was replaced with pure CO at 3.0 MPa, and the catalyst was replaced with a 30.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0176] After testing, under these reaction conditions, the cellulose conversion rate was 76.5%, the yields and selectivities of the product ketone compounds were 7.2% and 9.4% respectively, the other products were mainly alcohols and acids. The yields and selectivities of the alcohol compounds were 16.1% and 21.0% respectively, and the yields and selectivities of the acid compounds were 3.1% and 4.1% respectively. The total yields and selectivities of the ketone, alcohol and acid products were 26.4% and 34.5% respectively. The reaction results are shown in Table 1.

[0177] Table 1

[0178]

[0179]

[0180] As can be seen from Table 1, under the condition that the reasonable Pd loading defined in the present invention is 1-30 wt%, the hydrogen source gas containing CO in the present invention is mainly composed of hydrogen and CO, and the volume percentage content of CO is 3% - 85%. The cellulose conversion rate and the yield of ketone compounds in the examples are significantly higher than those of pure hydrogen and pure CO.

[0181] Under different reaction atmospheres (H 2 and CO with initial partial pressures of 0 - 3.0 MPa respectively, while maintaining the total pressure at 3.0 MPa), it can be seen from Comparative Examples 1-2 and Examples 4-8 that under the pure H 2 atmosphere, the cellulose conversion rate was 75.9%, the highest yield of the non-main product alcohol was 41.8%, and the yield of the ketone compound was only 5.6%. When the CO partial pressure was increased, the yield of the alcohol compound began to decrease, while the yield of the ketone compound began to increase. When H 2 / CO was 1.5 / 1.5 MPa, the yield of the ketone compound was 37.8%. This may be because CO inhibited the excessive hydrogenation of C=O in the ketone compound to form alcohol. Continuing to increase the CO partial pressure, the yields of both the ketone compound and the alcohol compound began to decrease, probably because too much CO adsorbed on Pd, resulting in insufficient catalytic active sites, and coupled with insufficient hydrogen, reducing the hydrogenolysis ability. When the reaction atmosphere was pure CO, the reaction effect was the worst. Comparing the above examples and comparative examples, it can be seen that H 2 plays an important role in the reaction, but CO and H 2 will play a synergistic role to promote the conversion of cellulose and the formation of ketone compounds. An appropriate mixture of H 2 and CO is helpful to improve the catalytic effect.

[0182] Normal hydrogen source gases all contain CO more or less, because most of the H 2It is obtained through the water-gas shift reaction, and it is not easy to remove CO. It is even more difficult to completely remove it. In the present invention, a supported Pd / C catalyst is used to carry out catalytic hydrodehydrogenation reaction in a non-pure hydrogen atmosphere containing CO. Moreover, the CO content in the hydrogen source gas of the present invention has a relatively large range. The volume percentage of CO in the reaction atmosphere can achieve the hydrodehydrogenation of cellulose to obtain ketone compounds from 3% to 85%, effectively reducing the reaction cost, and obtaining higher cellulose conversion rate and selectivity of ketone compounds. The present invention provides a feasible way for the efficient conversion of cellulose.

[0183] The implementation manners of the present invention are not limited thereto. Any other changes, modifications, combinations, simplifications made under the premise of violating the spirit and principle of the present invention should be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for preparing ketone compounds by hydrogenolysis of cellulose using a Pd / C supported catalyst, characterized in that: Cellulose is used as a raw material, water is used as a solvent, and activated carbon-loaded Pd is used as a catalyst. The reaction is carried out for 1 to 6 hours at a total pressure of 0.5-4.0 MPa and a temperature of 150-260° C. containing a hydrogen source gas of CO to obtain a product mainly composed of ketone compounds. The hydrogen source gas containing CO is mainly composed of hydrogen and CO, and the volume percentage content of CO is 3% to 85%. The Pd loading amount in the catalyst is 1-30wt%.

2. The method for preparing ketone compounds by hydrogenolysis of cellulose using a Pd / C supported catalyst according to claim 1, characterized in that: The Pd loading in the catalyst is 3-10wt%.

3. The method for preparing ketone compounds by hydrogenolysis of cellulose using a Pd / C supported catalyst according to claim 1, characterized in that: The mass ratio of cellulose to catalyst is 1:0.2-1:0.6, and the mass ratio of cellulose to water is 1:10-1:

20.

4. The method for preparing ketone compounds by hydrogenolysis of cellulose using a Pd / C supported catalyst according to claim 1, characterized in that: The volume percentage content of CO in the hydrogen source gas containing CO is preferably 10-50%.

5. The method for preparing ketone compounds by hydrogenolysis of cellulose using a Pd / C supported catalyst according to claim 1, characterized in that: The catalyst is prepared by the following steps: 1) dissolving a Pd source precursor in a solvent, adding ammonia water and water, and stirring to form a solution A; 2) adding water, alkali and carbon black powder to solution A under stirring to form liquid B; 3) subjecting liquid B to ultrasonic treatment, adding a reducing agent under inert atmosphere and stirring, heating to 20-90° C. and reacting for 0.5-6 hours; filtering, washing, and vacuum drying the reaction product to obtain a Pd / C catalyst; the reducing agent is at least one of NaBH4, vitamin C, and formaldehyde.

6. The method for preparing ketone compounds by hydrogenolysis of cellulose using a Pd / C supported catalyst according to claim 5, characterized in that: In step 1, the Pd source precursor is selected from at least one of PdCl2, Na2PdCl4 and K2PdCl4; the solvent is HCl or ultrapure water; the molar volume concentration of the Pd source precursor in the solution A is 1×10 -4 ~1×10 -1 mol / L; the molar ratio of the Pd source precursor to ammonia water is 1:10-50.

7. The method for preparing ketone compounds by hydrogenolysis of cellulose using a Pd / C supported catalyst according to claim 5, characterized in that: In step 2, the base is at least one of NaOH and KOH; the molar volume concentration of the base in liquid B is 0.05-0.3 mol / L, the volume mass ratio of water to carbon black powder is 1:(0.1-30), the volume unit is ml, and the mass unit is mg.

8. The method for preparing ketone compounds by hydrogenolysis of cellulose using a Pd / C supported catalyst according to claim 5, characterized in that: In step 3, the power of the ultrasonic treatment is 50-150 W, the time of the ultrasonic treatment is 20-120 min; the magnetic stirring time is 5-240 min; the molar ratio of Pd to the reducing agent is 1:1-1000; the heating rate of heating to 20-90° C. is 2-7° C. / min.

9. The method for preparing ketone compounds by hydrogenolysis of cellulose using a Pd / C supported catalyst according to claim 1, characterized in that: The cellulose is microcrystalline cellulose and / or natural cellulose.

10. The method for preparing ketone compounds by hydrogenolysis of cellulose using a Pd / C supported catalyst according to claim 1, characterized in that: The products mainly composed of ketone compounds include ketone compounds, alcohol compounds and acid compounds.

11. The method for preparing ketone compounds by hydrogenolysis of cellulose using a Pd / C supported catalyst according to claim 10, characterized in that: The ketone compound is one or more of 1-hydroxy-2-hexanone, 4-hydroxy-2-hexanone, cyclopentanone, 3-methylcyclopentanone, 2-hydroxy-3-hexanone, 2-methyl-2-cyclopentene-1-one and 2,5-hexanedione; the alcohol compound is one or more of ethanol and 1,2-hexanediol; and the acid compound is one or more of acetic acid, levulinic acid and hexanoic acid.

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