Crude hydrogen atmosphere-based method for preparing ketone compounds by catalytic hydrogenation of cellulose

Abstract

The invention discloses a method for preparing ketone compounds through catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere. 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 carbon monoxide and carbon dioxide is 0.5-4.0 MPa and the temperature is 230-260 DEG C to obtain a product mainly containing ketone compounds; the volume percent contents of the carbon monoxide and the carbon dioxide in the hydrogen source gas containing the carbon monoxide and the carbon dioxide are both 20%-67%. 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.

Description

Technical Field

[0001] The present invention relates to the preparation of ketone compounds, particularly a method for preparing ketone compounds by one-pot synthesis with H 2 / CO / CO 2 as the reaction atmosphere and cellulose as the raw material. Background Art

[0002] Cellulose is a polymer formed by the polymerization of glucose through glycosidic bonds. As shown in the following formula (a), 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]

[0004] The hydrogenation reaction of cellulose mainly refers to the process of converting this polysaccharide 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, in compounds containing multiple hydrogenation functional groups (such as containing -C=C, -C≡C, -C=O, etc.), it will hydrogenate all functional groups without selectivity. On the other hand, Pd is extremely easily poisoned by carbon monoxide (CO), which makes the purity requirement for the hydrogen (H 2 ) used in the hydrogenation process very high, and at least requires the purity of hydrogen to be higher than 99.99%.

[0005] Biomass-derived ketones are an important category of platform molecules and can be divided 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 chemically converted to synthesize a series of high-end chemical products for energy, food, medicine, and other various 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, people have been committed to developing new and efficient catalytic hydrogenation systems for this reaction.

[0006] Currently, most industrial hydrogen production adopts the natural gas steam reforming reaction process route. This process not only has low costs but also high technical maturity; however, the gas produced by this process mainly contains H 2 , CO and CO 2 , as shown in Table 1. The entire hydrogen production process by this method can be divided into four steps:

[0007] Table 1

[0008]

[0009] Firstly, in the raw material pretreatment stage, untreated natural gas usually contains a certain amount of impurities, such as hydrogen sulfide (H 2 S), carbon dioxide (CO 2 ), moisture, and other trace organic sulfides, etc. In order to avoid the poisoning effect of these impurities on the subsequent reforming reaction catalyst, it is necessary to pre-treat the natural gas. In this stage, impurities are mainly removed through processes such as desulfurization, decarbonization, and drying, so that the natural gas meets the purity standard required for the reforming reaction. After pretreatment, the content of the main component methane (CH 4 ) in natural gas is usually about 95%, and the content of other impurities is controlled at a very low level. For example, the hydrogen sulfide content can be reduced to below the ppm level, the carbon dioxide content is also greatly reduced, and the moisture is basically removed. The cost of this step accounts for about 10%.

[0010] The second step is the steam reforming reaction stage. The pre-treated natural gas is mixed with steam and then enters the reforming reactor. Inside the reactor, under high temperature (usually 700–900 °C) and the action of a catalyst, the methane steam reforming reaction occurs. The main chemical equation of this reaction is: CH 4 +H 2 O → CO + H 2 . This reaction occurs at a relatively low temperature of 200–500 °C and generally uses an iron-based or ketone-based catalyst. After the steam reforming reaction, the content of hydrogen (H 2 ) in the gas increases to 40% - 60%, the carbon monoxide (CO) content increases to 10% - 20%, the carbon dioxide (CO 2 ) content increases to about 20% - 30%, the methane (CH 4 ) is reduced to 10–15%, and the steam (H 2 O) content will also be adjusted accordingly. The cost of this step accounts for about 40–50%.

[0011] The third step is the water-gas shift reaction. The gas mixture coming out of the steam reforming reactor enters the water-gas shift reaction. In this reaction, CO reacts further with H 2 O to generate CO 2 and H 2 (CO + H2 O→H 2 +CO 2 )。 The water-gas shift reaction is usually carried out at relatively low temperatures (200 - 500 °C), generally using iron-based or copper-based catalysts. This reaction is a reversible reaction, and the reaction equilibrium and product composition are adjusted by controlling conditions such as reaction temperature, pressure, and reactant concentration. After the water-gas shift reaction, the content of H 2 in the gas is further increased to 60–80%, the CO content is reduced to 5 - 10%, and the CO 2 content is reduced to 18–25%. The cost ratio of this step is 10 - 15%.

[0012] The final stage is gas purification. The syngas after the above reaction steps still contains a small amount of impurities, such as unreacted carbon dioxide (CO 2 ), carbon monoxide (CO), etc. To meet the strict requirements for the purity of syngas in subsequent industrial applications, gas purification is required to remove impurities. Common purification methods include pressure swing adsorption and membrane separation technologies. Through these methods, the purity of hydrogen can be increased to more than 99%, and impurities such as carbon dioxide are separated and recovered. The cost ratio of this step is about 20 - 30%.

[0013] As can be seen from the above, the production cost of high-purity hydrogen is significantly higher than that of crude hydrogen; and the use of high-purity hydrogen also increases the cost of catalytic hydrogenation reactions in industry.

[0014] Chinese invention patent CN109896938B discloses a method for preparing 2,5-hexanedione. This method uses a liquid acid and a supported noble metal to coordinately catalyze the conversion of biomass to obtain 2,5-hexanedione. However, the liquid acids such as hydrochloric acid used in this technology still have problems such as corrosion and recovery, and the noble metal catalysts used also increase the cost of producing 2,5-hexanedione.

[0015] Chinese invention patent CN115259995B discloses a method for catalytic hydrogenolysis of lignocellulose to prepare vicinal diols. This method uses a magnetic metal catalyst wrapped with a graphene-like carbon shell layer. Under specific reaction conditions (such as reaction temperature of 120 - 220 °C, reaction time of 2 - 4 hours, and hydrogen pressure of 5.5 MPa), lignocellulose is efficiently converted into vicinal diols. Although this technology can efficiently prepare diols, the reaction requires a large amount of high-purity hydrogen, resulting in high production costs and difficulty in industrialization; and currently, hydrogenolysis of cellulose and even the entire biomass requires high-purity hydrogen. Summary of the Invention

[0016] Aiming at the problems existing in the prior art, the present invention aims to provide a method for catalytic hydrogenation of cellulose to prepare ketone compounds based on a crude hydrogen atmosphere, which has mild reaction conditions, is environmentally friendly, has high catalytic efficiency, and the yield of ketone compounds reaches 10.6 - 42.5%. The method can realize catalytic hydrogenation reaction under a non-pure hydrogen atmosphere, significantly reducing the cost of catalytic hydrogenation reaction.

[0017] The object of the present invention is achieved by the following technical solutions:

[0018] A method for catalytic hydrogenation of cellulose to prepare ketone compounds based on a crude hydrogen atmosphere, characterized in that: 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 230 - 260 °C for 1 - 6 h in a hydrogen source gas containing carbon monoxide and carbon dioxide to obtain a product mainly composed of ketone compounds; the volume percentage content of carbon monoxide and carbon dioxide in the hydrogen source gas containing carbon monoxide and carbon dioxide is 20% - 67% each; the Pd loading in the catalyst is 1 - 20 wt%.

[0019] To further achieve the object of the present invention, preferably, the Pd loading in the catalyst is 3 - 10 wt%.

[0020] 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.

[0021] Preferably, the volume percentage content of carbon monoxide and carbon dioxide in the hydrogen source gas containing carbon monoxide and carbon dioxide is 33.3 - 50% each.

[0022] Preferably, the catalyst is prepared by the following steps:

[0023] 1) Dissolve the Pd source precursor in a solvent, add ammonia water and water, and form solution A under stirring;

[0024] 2) Add water, a base, and carbon black powder to solution A under stirring to form liquid B;

[0025] 3) Ultrasonically treat liquid B, add a reducing agent under an inert atmosphere and stirring, heat to 20 - 90 °C and react for 0.5 - 6 h; filter, wash, and vacuum dry the reaction product to obtain the Pd / C catalyst; the reducing agent is at least one of NaBH 4 , vitamin C, and formaldehyde.

[0026] Preferably, in step 1, the Pd source precursor is selected from PdCl 2 , Na 2 PdCl 4 and K 2PdCl 4 At least one of; 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 to 50.

[0027] 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 to 0.3 mol / L, and the volume-mass ratio of water to carbon black powder is 1:(0.1 to 30), with the volume unit being ml and the mass unit being mg.

[0028] Preferably, in step 3, the power of the ultrasonic treatment is 50 to 150 W, the time of the ultrasonic treatment is 20 to 120 min; the magnetic stirring time is 5 to 240 min; the molar ratio of Pd to the reducing agent is 1:1 to 1000; the heating rate to 20 to 90 °C is 2 to 7 °C / min.

[0029] Preferably, the cellulose is microcrystalline cellulose and / or natural cellulose.

[0030] Preferably, the products mainly composed of ketone compounds include ketone compounds, alcohol compounds and acid compounds.

[0031] 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.

[0032] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0033] CO in the present invention will inhibit the over-hydrogenation of the product C=O, and CO 2 will release H in high-temperature water + (CO 2 (aq)+H 2 O→H + +HCO 3 - →2H + +CO 3 2- ) to accelerate the hydrolysis reaction, and CO in the reaction will undergo a water-gas shift reaction (WGSR) with H 2 O (CO+H 2 O→H2 + CO 2 ) to generate H 2 and CO 2 , which can further promote the hydrocracking and hydrolysis reactions. When the carbon-supported catalyst of the present invention is applied to the catalytic hydrogenation reaction, the CO and CO contained in the hydrogen source gas used 2 The volume percentage of can be greater than 15%. Therefore, crude hydrogen with a higher content of CO and CO 2 can be used for the catalytic hydrogenation reaction of cellulose, thereby reducing the cost of the cellulose catalytic reaction.

[0034] 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, high added value and economic value of the product, and provides an effective way to prepare ketone compounds from biomass.

[0035] The present invention develops a novel hydrocracking strategy to replace the traditional hydrocracking technology and provides a method for realizing sustainable and cost-effective biomass utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is the TEM image of 5 wt% Pd / C in Example 5.

[0037] Figure 2 is the particle size distribution diagram of 5 wt% Pd / C in Example 5.

[0038] Figure 3 is the FID spectrum of the product obtained by depolymerization of cellulose in Example 8.

[0039] Figure 4 is the HPLC spectrum of the product obtained by depolymerization of cellulose in Example 8. DETAILED DESCRIPTION OF THE INVENTION

[0040] To better understand the present invention, the present invention will be further described below with reference to the drawings and examples, but the embodiments of the present invention are not limited thereto.

[0041] 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 using a Pd / C-supported catalyst for catalytic hydrogenation reaction, the hydrogen source gas that provides hydrogen elements for the catalytic hydrogenation reaction contains CO and CO 2 , and CO and CO 2The volume percentage can efficiently achieve the preparation of ketone compounds by catalytic hydrogenolysis of cellulose over Pd / C supported catalysts within a very wide range of 20% to 67%. Specifically, the method for catalytic hydrogenation of cellulose to prepare ketone compounds based on a crude hydrogen atmosphere in the present invention: using cellulose as a raw material, water as a solvent, activated carbon supported Pd as a catalyst, reacting at a total pressure of the hydrogen source gas containing CO and CO 2 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 source gas containing CO and CO 2 is mainly composed of H 2 , CO and CO 2 , and the volume percentage content of CO and CO 2 is 20% - 67%; the Pd loading in the catalyst is 1 - 20 wt%.

[0042] The present invention uses crude hydrogen (containing CO and CO 2 ) as the hydrogen source, and it is found that the hydrogen source containing CO and CO 2 not only has no negative impact on the reaction, but instead promotes the reaction:

[0043] (1) CO can inhibit over-hydrogenation and prevent the -C=O from being hydrogenated, thus highly selectively producing high-value ketone compounds, and the ketone compounds mainly include 2,5-hexanedione and 1-hydroxy-2-hexanone, etc.

[0044] (2) The solvent of this reaction system is water, and CO 2 will continue to react with water at high temperature to generate H 2 CO 3 , and H 2 CO 3 decomposes to produce H + (CO 2 (aq) + H 2 O → H 2 CO 3 → H + + HCO 3 - ) provides an acidic condition for the reaction and promotes the hydrolysis reaction. Therefore, CO 2 in the reaction atmosphere will promote the hydrolysis reaction, and CO in the reaction atmosphere will react with H 2 O to undergo the WGSR to produce H 2 and CO 2 , further promoting the hydrogenolysis and hydrolysis reactions, thus increasing the yield of ketone compounds in the product.

[0045] Currently, the main method for industrial hydrogen production is natural gas steam reforming, and the gas content of each step is as shown in Table 1 above. Therefore, using hydrogen containing CO and CO2 H of 2 The industrial significance of the reaction atmosphere lies in providing a wider range of selectivity for the reaction atmosphere of cellulose hydrocracking industrialization, thereby significantly reducing the industrialization cost. The main role of CO in the reaction is to inhibit excessive hydrogenation, because the CO generated through the WGSR 2 is insufficient, resulting in insufficient hydrolysis reaction. Therefore, additional CO 2 can make up for the disadvantage of insufficient hydrolysis reaction caused by insufficient CO 2 . Compared with the best results under the H 2 / CO atmosphere, the ketone yield of H 2 / CO / CO 2 has a significant increase, 37.8 vs 42.5%.

[0046] The reaction raw material of the present invention is cellulose, and the hydrogen source gas containing CO and CO 2 directly or indirectly provides hydrogen species and an acidic environment for the reaction. Cellulose first reacts under hydrothermal conditions to generate glucose, and glucose will undergo multiple reactions, including ring-opening to form 1-hydroxy-2-butanone (HB), hydrodeoxygenation reaction to form 1-hydroxy-2-hexanone (HHO), and isomerization to form fructose. Fructose dehydrates to form 5-hydroxymethylfurfural (HMF), and then through a series of reactions such as hydrogenation and hydrolysis, a series of products such as 2,5-hexanedione are formed.

[0047] 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.

[0048] The reagents, materials, etc. used in the following examples are all common raw materials in the art and can be obtained through commercial channels without special instructions.

[0049] Example 1: Preparation of a Pd / C supported catalyst with a Pd content of 1.0 wt%:

[0050] 1. Add 0.02 g of PdCl 2 , and 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;

[0051] 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;

[0052] 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 gas atmosphere;

[0053] 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;

[0054] 5. Heat the above mixture at a heating rate of 2.0 °C / min to 60.0 °C, and carry out a constant-temperature reaction at this temperature for 2.0 h;

[0055] 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%.

[0056] Example 2: Preparation of a Pd / C supported catalyst with a Pd content of 1.0 wt%:

[0057] 1. Dissolve 0.02 g of Na 2 PdCl 4 in 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 in the solution is 1.8×10 -2 M, and the molar ratio of Na 2 PdCl 4 to ammonia water is 1:22;

[0058] 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;

[0059] 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 gas atmosphere;

[0060] 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;

[0061] 5. Heat the above-mentioned mixed solution at a heating rate of 2.0 °C / min to 60.0 °C, and carry out a constant-temperature reaction at this temperature for 2.0 h;

[0062] 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%.

[0063] Example 3: Preparation of a Pd / C supported catalyst with a Pd content of 1.0 wt%:

[0064] 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;

[0065] 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;

[0066] 3. Add 0.9 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;

[0067] 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;

[0068] 5. Heat the above-mentioned mixed solution at a heating rate of 2.0 °C / min to 60.0 °C, and carry out a constant-temperature reaction at this temperature for 2.0 h;

[0069] 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%.

[0070] Example 4: Preparation of a Pd / C supported catalyst with a Pd content of 1.0 wt%:

[0071] 1. Dissolve 0.02 g of K2 PdCl 4 , add ultrapure water to prepare a 0.1 M solution of 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;

[0072] 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;

[0073] 3. Add 0.9 g of carbon black powder to the flask, sonicate it 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 gas atmosphere;

[0074] 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;

[0075] 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;

[0076] 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. It is detected that the mass fraction of Pd in the obtained catalyst is 1.0 wt%.

[0077] Example 5: Preparation of a Pd / C supported catalyst with a Pd content of 5.0 wt%:

[0078] 1. Weigh 0.02 g of PdCl 2 into a flask, add HCl to prepare a 0.1 M solution of 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;

[0079] 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;

[0080] 3. Add 0.2 g of carbon black powder to the flask, sonicate 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;

[0081] 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;

[0082] 5. Heat the above mixture at a heating rate of 7.0 °C / min to 90.0 °C and keep it reacting at this temperature for 0.5 h;

[0083] 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, Figure 1 which is the TEM image of 5 wt% Pd / C in Example 5. As Figure 1 shown, the dispersion of Pd in carbon black is good and the particle size is uniform. The mass fraction of Pd in the obtained catalyst is detected to be 5.0 wt%, Figure 2 which is the particle size distribution diagram of 5 wt% Pd / C in Example 5. As Figure 2 shown, the Pd particle size is about 8.0 nm.

[0084] Example 6: Preparation of a Pd / C supported catalyst with a Pd content of 5.0 wt%:

[0085] 1. Weigh 0.1 g of PdCl 2 into the flask, add HCl to prepare a 0.1 M H 2 PdCl 4 solution, then add 25.0 mL of water, and 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;

[0086] 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;

[0087] 3. Add 1.0 g of carbon black powder to the flask, ultrasonicate it for 5.0 min at a power of 150 W, then transfer the flask to an oil bath and magnetically stir it for 4.0 h under an Ar atmosphere;

[0088] 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;

[0089] 5. Heat the above mixture at a heating rate of 4.0 °C / min to 20.0 °C and keep it reacting at this temperature for 6.0 h;

[0090] 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 Figure 2 shown, Pd has good dispersion in carbon black and uniform particle size. The mass fraction of Pd in the obtained catalyst is detected to be 5.0 wt%, and the Pd particle size is about 8.0 nm.

[0091] Example 7: Preparation of a Pd / C supported catalyst with a Pd content of 30.0 wt%:

[0092] 1. Weigh 0.02 g of PdCl 2 into the 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 magnetically stir until the solution becomes colorless and transparent; the molar volume concentration of H 2 PdCl 4 in the solution is 1.8×10 -2 mol / L, and the molar ratio of H 2 PdCl 4 to ammonia water is 1:22;

[0093] 2. Add 30.0 mL of ultrapure water to the flask, then add 1.5 mL of 1.0 M NaOH solution and magnetically stir for 20.0 min;

[0094] 3. Add 400 mg of carbon black powder to the flask, ultrasonicate it for 30.0 min at a power of 100 W, then transfer the flask to an oil bath and magnetically stir it for 2.0 h under an Ar atmosphere;

[0095] 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;

[0096] 5. Heat the above-mentioned mixed solution at a heating rate of 2.0 °C / min to 60.0 °C and keep it reacting at this temperature for 2.0 h;

[0097] 6. Filter the obtained reaction product by suction, 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. It is detected that the mass fraction of Pd in the obtained catalyst is 30.0 wt%.

[0098] Example 8: Method for catalytically preparing ketone compounds from cellulose under H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa) atmosphere:

[0099] 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 / CO 2 (0.5 / 1.0 / 1.5 MPa). Heat the reactor to 230.0 °C and react for 2.0 h. After the reaction is completed, cool the reactor to room temperature, filter the reaction mixture, and then extract and enrich the volatile products with dichloromethane (DCM) (5.0 mL × 5 times) to obtain an aqueous phase and a dichloromethane phase. After the residue is washed five times with tetrahydrofuran (5.0 mL × 5 times), it is vacuum dried at 60.0 °C for 12.0 h, and the cellulose conversion rate is calculated by weighing. For the aqueous phase (containing water-soluble products such as acids and alcohols), methanol is removed by vacuum distillation at 45.0 °C, collected and fixed to 50.0 mL with ultrapure water, and the aqueous phase products are qualitatively analyzed by liquid chromatography-mass spectrometry (HPLC-MS). The chromatographic column is an HPX-87H sugar column (300 mm × 7.8 mm, 5 μm), a differential refractive index detector (RID), the detector temperature is 50.0 °C, and the mobile phase is 5.0 mM H 2 SO 4 , the flow rate is 0.6 mL min -1 , and the column temperature is 65.0 °C.

[0100] The quantitative analysis of each component was carried out by using the characterization curve method. For the dichloromethane phase (containing volatile products such as ketones), dimethyl phthalate (internal standard) was added thereto and made up to 25.0 mL with dichloromethane, and qualitative analysis was carried out by using a gas chromatography-mass spectrometry (GC-MS), and quantitative determination was carried out by GC. The chromatographic column was an HP-5MS 5% phenyl methyl silox capillary column (30 m×0.25 μm×0.25 μm), the inlet temperature was 270.0 °C, a flame ionization detector (FID) was used, the detector temperature was 270.0 °C, the carrier gas was He, and the flow rate was 1.0 mL min -1 , and the column temperature was a temperature programming procedure. The initial column oven temperature was 50.0 °C (maintained for 3.0 min), and the temperature was increased at a 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, and the split ratio was 10:1. The situation of qualitative analysis was as shown in Figure 3 and Figure 4 . Figure 3 is the FID chromatogram (gas chromatography) of the product obtained by depolymerization of cellulose in Example 8; Figure 4 is the HPLC chromatogram (liquid chromatography) of the product obtained by depolymerization of cellulose in Example 8; By analyzing and detecting, ketone compound products and alcohol products appearing at different retention times were obtained, and among them, 1-hydroxy-2-hexanone, 2-hydroxy-3-hexanone, ethyl propionate, 2-methyl-2-cyclopentene and 2,5-hexanedione with the largest peak area were the main products.

[0101] The cellulose conversion rate Conversion (%) was calculated based on the dry weight of the remaining solid, as shown in Formula 1. The carbon yield Carbon yield (%) of the liquid product was calculated by Formula 2, and the selectivity of the liquid product was calculated by Formula 3.

[0102]

[0103] Among them, m 1 is the mass of the original cellulose, 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, k i is the carbon atom in product i, m cellulose is the weight of the initial cellulose, is the relative molecular mass of the glucose unit, carbon yield i is the carbon yield of product i, 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 iis the molar amount of 2,5 - hexanedione, k i is the number of carbon atoms of 2,5 - hexanedione.

[0104] After testing, under the action of Pd / C catalyst, the unreacted raw material (m 2 ) is 0.044 g. The remaining solid dry weight calculation method (Formula 1) is used:

[0105]

[0106] The conversion rate of cellulose is 91.2%. The yield formula 2 of the liquid product is used for calculation. For example, the yields of 1 - hydroxy - 2 - hexanone and 2,5 - hexanedione are calculated by the calculation method (Formula 2):

[0107]

[0108] Calculated in the same way, the yields of 2 - methylcyclopentanone, 2 - hydroxy - 3 - hexanone, 2 - methyl - 2 - cyclopenten - 1 - one are 1.9%, 9.2% and 9.1% respectively. Thus, the total yield of the product ketones is 42.5%. The product selectivity of the ketone compounds is calculated by Formula 3 as 46.6%. Other products are mainly alcohols (pentanol, tetrahydrofurfuryl alcohol and 1,2 - hexanediol) and acid (valeric acid) products. The yields and selectivities of the alcohol compounds are 15.1% and 16.6% respectively, and the yields and selectivities of the acid compounds are 7.2% and 7.9% respectively. The total yields and selectivities of the ketone, alcohol and acid products are 64.8% and 71.1% respectively. The test results are shown in Table 2.

[0109] Example 9: Method for catalyzing cellulose with 5.0 wt% Pd / C in H 2 / CO / CO 2 (2.0 / 0.5 / 0.5 MPa) atmosphere:

[0110] In this example, the steps of the Pd / C - catalyzed cellulose hydro - depolymerization process are the same as those in Example 8, except that the reaction atmosphere is replaced with 3.0 MPa of H 2 / CO / CO 2 (2.0 / 0.5 / 0.5 MPa). Cellulose (0.5 g), 5.0 wt% Pd / C catalyst (0.2 g), deionized water (20.0 mL) are heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0111] After testing, the cellulose conversion rate under this reaction condition is 78.5%, and the yields and selectivities of the product ketone compounds are 18.5% and 23.6% respectively. The other products are mainly alcohol and acid products. The yields and selectivities of the alcohol compounds are 24.5% and 31.2% respectively, and the yields and selectivities of the acid compounds are 11.8% and 15.0% respectively. The total yields and selectivities of the ketone, alcohol and acid products are 52.8% and 67.3% respectively. The test results are shown in Table 2.

[0112] Example 10: Method for catalyzing cellulose by 5.0 wt% Pd / C in H 2 / CO / CO 2 (1.5 / 1.0 / 0.5 MPa) atmosphere:

[0113] In this example, the steps of the Pd / C-catalyzed cellulose hydrodepolymerization process are the same as those in Example 8, except that the reaction atmosphere is replaced by H 2 / CO / CO = 1.5 / 1.0 / 0.5 MPa. Cellulose (0.5 g), 5.0 wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) are heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0114] After testing, the cellulose conversion rate under this reaction condition is 89.1%, and the yields and selectivities of the main product ketone compounds are 37.2% and 41.8% respectively. The other products are mainly alcohol and acid products. The yields and selectivities of the alcohol compounds are 22.1% and 24.8% respectively, and the yields and selectivities of the acid compounds are 8.5% and 9.5% respectively. The total yields and selectivities of the ketone, alcohol and acid products are 67.8% and 76.1% respectively. The test results are shown in Table 2.

[0115] Example 11: Method for catalyzing cellulose by 5.0 wt% Pd / C in H 2 / CO / CO 2 (1.5 / 0.5 / 1.0 MPa) atmosphere:

[0116] In this example, the steps of the Pd / C-catalyzed cellulose hydrodepolymerization process are the same as those in Example 8, except that the reaction atmosphere is replaced by H 2 / CO / CO 2 (1.5 / 0.5 / 1.0 MPa). Cellulose (0.5 g), 5.0 wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) are heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0117] After testing, the conversion rate of cellulose under this reaction condition was 90.6%, the yields and selectivities of the main product ketone compounds were 33.0% and 36.4% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of alcohol compounds were 25.2% and 27.8% respectively, the yields and selectivities of acid compounds were 10.7% and 11.8% respectively, and the total yields and selectivities of ketone, alcohol and acid products were 68.9% and 76.0% respectively. The test results are shown in Table 2.

[0118] Example 12: Method for catalyzing cellulose by 5.0 wt% Pd / C in H 2 / CO / CO 2 (1.0 / 1.5 / 0.5 MPa) atmosphere:

[0119] In this example, the steps of the Pd / C-catalyzed cellulose hydrocracking process were the same as those in Example 8, except that the reaction atmosphere was replaced with 3.0 MPa of H 2 / CO / CO 2 (1.0 / 1.5 / 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.

[0120] After testing, the conversion rate of cellulose under this reaction condition was 82.5%, the yields and selectivities of the main product ketone compounds were 36.2% and 49.5% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of alcohol compounds were 19.3% and 23.4% respectively, the yields and selectivities of acid compounds were 8.1% and 9.8% respectively, and the total yields and selectivities of ketone, alcohol and acid products were 63.6% and 77.1% respectively. The test results are shown in Table 2.

[0121] Example 13: Method for catalyzing cellulose by 5.0 wt% Pd / C in H 2 / CO / CO 2 (1.0 / 1.0 / 1.0 MPa) atmosphere:

[0122] In this example, the steps of the Pd / C-catalyzed cellulose hydrocracking process were the same as those in Example 8, except that the reaction atmosphere was replaced with 3.0 MPa of H 2 / CO / CO 2 (1.0 / 1.0 / 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.

[0123] After testing, the cellulose conversion rate under this reaction condition was 77.6%, the yields and selectivities of the main product ketone compounds were 31.1% and 40.1% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 21.5% and 27.7% respectively, the yields and selectivities of the acid compounds were 7.4% and 9.5% respectively, the total yields and selectivities of the ketone, alcohol and acid products were 60.0% and 77.3% respectively, and the test results are shown in Table 2.

[0124] Example 14: Method for catalyzing cellulose by 5.0 wt% Pd / C in H 2 / CO / CO 2 (1.0 / 0.5 / 1.5 MPa) atmosphere:

[0125] In this example, the steps of the Pd / C-catalyzed cellulose hydrocracking and depolymerization process were the same as those in Example 8, except that the reaction atmosphere was replaced with 3.0 MPa of H 2 / CO / CO 2 (1.0 / 0.5 / 1.5 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.

[0126] After testing, the cellulose conversion rate under this reaction condition was 83.5%, the yields and selectivities of the main product ketone compounds were 28.1% and 33.7% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 27.2% and 32.6% respectively, the yields and selectivities of the acid compounds were 5.2% and 6.2% respectively, the total yields and selectivities of the ketone, alcohol and acid products were 60.5% and 72.5% respectively, and the test results are shown in Table 2.

[0127] Example 15: Method for catalyzing cellulose by 5.0 wt% Pd / C in H 2 / CO / CO 2 (0.5 / 2.0 / 0.5 MPa) atmosphere:

[0128] In this example, the steps of the Pd / C-catalyzed cellulose hydrocracking and depolymerization process were the same as those in Example 8, except that the reaction atmosphere was replaced with 3.0 MPa of H 2 / CO / CO 2 (0.5 / 2.0 / 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.

[0129] After testing, the cellulose conversion rate under this reaction condition was 79.7%, the yields and selectivities of the main product ketone compounds were 25.3% and 31.7% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 13.2% and 16.6% respectively, the yields and selectivities of the acid compounds were 4.9% and 6.1% respectively, the total yields and selectivities of the ketone, alcohol and acid products were 43.4% and 54.5% respectively, and the test results are shown in Table 2.

[0130] Example 16: Method for catalyzing cellulose by 5.0 wt% Pd / C in H 2 / CO / CO 2 (0.5 / 1.5 / 1.0 MPa) atmosphere:

[0131] In this example, the steps of the Pd / C-catalyzed cellulose hydrocracking process were the same as those in Example 8, except that the reaction atmosphere was replaced with 3.0 MPa of H 2 / CO / CO 2 (0.5 / 1.5 / 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.

[0132] After testing, the cellulose conversion rate under this reaction condition was 76.1%, the yields and selectivities of the main product ketone compounds were 24.5% and 32.2% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 14.8% and 19.4% respectively, the yields and selectivities of the acid compounds were 4.6% and 6.0% respectively, the total yields and selectivities of the ketone, alcohol and acid products were 43.9% and 57.7% respectively, and the test results are shown in Table 2.

[0133] Example 17: Method for catalyzing cellulose by 5.0 wt% Pd / C in H 2 / CO / CO 2 (0.5 / 0.5 / 2.0 MPa) atmosphere:

[0134] In this example, the steps of the Pd / C-catalyzed cellulose hydrocracking process were the same as those in Example 8, except that the reaction atmosphere was replaced with 3.0 MPa of H 2 / CO / CO 2 (0.5 / 0.5 / 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.

[0135] After testing, the cellulose conversion rate under this reaction condition was 80.3%, the yields and selectivities of the main product ketone compounds were 21.9% and 27.3% respectively, the other products were mainly alcohols and acid products, the yields and selectivities of alcohol compounds were 16.7% and 20.8% respectively, the yields and selectivities of acid compounds were 3.4% and 4.2% respectively, the total yields and selectivities of ketone, alcohol and acid products were 42.0% and 52.3% respectively, and the test results are shown in Table 2.

[0136] Example 18: Method for catalyzing cellulose by 1.0 wt% Pd / C in H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa) atmosphere:

[0137] In this example, the steps of the Pd / C-catalyzed cellulose hydrocracking process were the same as those in Example 8, except that the reaction atmosphere was replaced with H at 3.0 MPa 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa), and the catalyst was replaced with 1.0 wt% Pd / C (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.

[0138] After testing, the cellulose conversion rate under this reaction condition was 75.9%, the yields and selectivities of the main product ketone compounds were 10.6% and 14.0% respectively, the other products were mainly alcohols and acid products, the yields and selectivities of alcohol compounds were 21.8% and 28.7% respectively, the yields and selectivities of acid compounds were 9.0% and 11.9% respectively, the total yields and selectivities of ketone, alcohol and acid products were 41.4 and 54.5%, and the test results are shown in Table 2.

[0139] Example 19: Method for catalyzing cellulose by 10.0 wt% Pd / C in H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa) atmosphere:

[0140] In this example, the steps of the Pd / C-catalyzed cellulose hydrocracking process were the same as those in Example 8, except that the reaction atmosphere was replaced with H at 3.0 MPa 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa), and the catalyst was replaced with 10.0 wt% Pd / C (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.

[0141] After testing, the cellulose conversion rate under this reaction condition was 86.1%, the yields and selectivities of the main product ketone compounds were 34.6% and 40.2% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of alcohol compounds were 20.6% and 23.9% respectively, the yields and selectivities of acid compounds were 8.5% and 9.9% respectively, the total yields and selectivities of ketone, alcohol and acid products were 63.7 and 74.0%, and the test results are shown in Table 2.

[0142] Example 20: Method for catalyzing cellulose by 15.0 wt% Pd / C in H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa) atmosphere:

[0143] In this example, the steps of the Pd / C-catalyzed cellulose hydrocracking process were the same as those in Example 8, except that the reaction atmosphere was replaced with 3.0 MPa of H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa), and the catalyst was replaced with 15.0 wt% Pd / C (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.

[0144] After testing, the cellulose conversion rate under this reaction condition was 92.3%, the yields and selectivities of the main product ketone compounds were 30.8% and 33.4% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of alcohol compounds were 22.3% and 24.2% respectively, the yields and selectivities of acid compounds were 7.1% and 7.7% respectively, the total yields and selectivities of ketone, alcohol and acid products were 60.2% and 65.2%, and the test results are shown in Table 2.

[0145] Example 21: Method for catalyzing cellulose by 20.0 wt% Pd / C in H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa) atmosphere:

[0146] In this example, the steps of the Pd / C-catalyzed cellulose hydrocracking process were the same as those in Example 8, except that the reaction atmosphere was replaced with 3.0 MPa of H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa), and the catalyst was replaced with 20.0 wt% Pd / C (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.

[0147] After testing, the conversion rate of cellulose under this reaction condition was 91.7%, the yields and selectivities of the main product ketone compounds were 15.3% and 16.7% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of alcohol compounds were 34.5% and 37.6% respectively, the yields and selectivities of acid compounds were 9.6% and 10.5% respectively, and the total yields and selectivities of ketone, alcohol and acid products were 59.4% and 64.8% respectively. The test results are shown in Table 2.

[0148] Example 22: Method for catalyzing cellulose by 5.0 wt% Pd / C in H 2 / CO / CO 2 (0.7 / 1.2 / 2.1 MPa) atmosphere:

[0149] In this example, the steps of the Pd / C-catalyzed hydrogenolysis process of cellulose were the same as those in Example 8, except that the reaction atmosphere was replaced with H 2 / CO / CO 2 (0.7 / 1.2 / 2.1 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.

[0150] After testing, the conversion rate of cellulose under this reaction condition was 88.5%, the yields and selectivities of the main product ketone compounds were 38.1% and 43.1% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of alcohol compounds were 14.5% and 16.4% respectively, the yields and selectivities of acid compounds were 5.9% and 6.7% respectively, and the total yields and selectivities of ketone, alcohol and acid products were 58.5% and 66.1% respectively. The test results are shown in Table 2.

[0151] Example 23: Method for catalyzing cellulose by 5.0 wt% Pd / C in H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa) atmosphere:

[0152] In this example, the steps of the Pd / C-catalyzed hydrogenolysis process of cellulose were the same as those in Example 8, except that the reaction atmosphere was replaced with H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa). Cellulose (0.5 g), 5.0 wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) were heated to 210.0 °C in a reaction kettle and reacted for 2.0 h.

[0153] After testing, the conversion rate of cellulose under this reaction condition was 71.1%, the yields and selectivities of the main product ketone compounds were 28.2% and 39.7% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of alcohol compounds were 11.4% and 16.0% respectively, the yields and selectivities of acid compounds were 3.1% and 4.4% respectively, and the total yields and selectivities of ketone, alcohol and acid products were 42.7% and 60.1% respectively. The test results are shown in Table 2.

[0154] Example 24: Method for catalyzing cellulose by 5.0 wt% Pd / C in H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa) atmosphere:

[0155] In this example, the steps of the Pd / C-catalyzed hydrogenolysis process of cellulose were the same as those in Example 8, except that the reaction atmosphere was replaced with H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa). Cellulose (0.5 g), 5.0 wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) were heated to 260.0 °C in a reaction kettle and reacted for 2.0 h.

[0156] After testing, the conversion rate of cellulose under this reaction condition was 92.3%, the yields and selectivities of the main product ketone compounds were 35.6% and 38.6% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of alcohol compounds were 16.2% and 17.6% respectively, the yields and selectivities of acid compounds were 7.4% and 8.0% respectively, and the total yields and selectivities of ketone, alcohol and acid products were 59.2% and 64.1% respectively. The test results are shown in Table 2.

[0157] Example 25: Method for catalyzing cellulose by 5.0 wt% Pd / C in H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa) atmosphere:

[0158] In this example, the steps of the Pd / C-catalyzed hydrogenolysis process of cellulose were the same as those in Example 8, except that the reaction atmosphere was replaced with H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 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 1.0 h.

[0159] After testing, the cellulose conversion rate under this reaction condition was 72.5%, the yields and selectivities of the main product ketone compounds were 21.1% and 29.1% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 14.2% and 20.4% respectively, the yields and selectivities of the acid compounds were 4.1% and 5.9% respectively, the total yields and selectivities of the ketone, alcohol and acid products were 38.6% and 55.4% respectively, and the test results are shown in Table 2.

[0160] Example 26: Method for catalyzing cellulose by 5.0 wt% Pd / C in H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 MPa) atmosphere:

[0161] In this example, the steps of the Pd / C-catalyzed cellulose hydrodepolymerization process were the same as those in Example 8, except that the reaction atmosphere was replaced with H 2 / CO / CO 2 (0.5 / 1.0 / 1.5 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 6.0 h.

[0162] After testing, the cellulose conversion rate under this reaction condition was 92.9%, the yields and selectivities of the main product ketone compounds were 32.1% and 34.6% respectively, the other products were mainly alcohol and acid products, the yields and selectivities of the alcohol compounds were 19.5% and 21.0% respectively, the yields and selectivities of the acid compounds were 7.5% and 8.1% respectively, the total yields and selectivities of the ketone, alcohol and acid products were 59.1% and 63.6% respectively, and the test results are shown in Table 2.

[0163] Example 27: Method for catalyzing cellulose by 5.0 wt% Pd / C in H 2 / CO / CO 2 (0.2 / 0.4 / 0.4 MPa) atmosphere:

[0164] In this example, the steps of the Pd / C-catalyzed cellulose hydrodepolymerization process were the same as those in Example 8, except that the reaction atmosphere was replaced with H 2 / CO / CO 2 (0.2 / 0.4 / 0.4 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.

[0165] After testing, under these reaction conditions, the conversion rate of cellulose was 70.2%, the yields and selectivities of the main product ketone compounds were 22.1% and 33.7% respectively. The other products were mainly alcohols and acids. The yields and selectivities of the alcohol compounds were 9.4% and 13.5% respectively, and the yields and selectivities of the acid compounds were 2.1% and 3.0% respectively. The total yields and selectivities of the ketone, alcohol and acid products were 33.7% and 48.0% respectively. The test results are shown in Table 2.

[0166] Comparative Example 1

[0167] In this comparative example, the reaction atmosphere used was H 2 / CO (2.9 / 0.1 MPa).

[0168] The method for catalyzing cellulose using 5.0 wt% Pd / C in an H 2 / CO (2.9 / 0.1 MPa) atmosphere:

[0169] In this comparative example, the steps of the hydrogenolysis and depolymerization process of cellulose catalyzed by Pd / C were the same as those in Example 8, except that the reaction atmosphere was replaced with H 2 / CO = 2.9 / 0.1 MPa 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.

[0170] After testing, under these reaction conditions, the conversion rate of cellulose was 76.6%, the yields and selectivities of the product ketone compounds were 8.9% and 11.6% respectively. The other products were mainly alcohols and acids. The yields and selectivities of the alcohol compounds were 35.1% and 45.8% respectively, and the yields and selectivities of the acid compounds were 8.6% and 11.2% respectively. The total yields and selectivities of the ketone, alcohol and acid products were 52.6% and 68.7% respectively. The reaction results are listed in Table 2.

[0171] Comparative Example 2

[0172] In this comparative example, the reaction atmosphere used was H 2 / CO 2 (2.9 / 0.1 MPa).

[0173] The method for catalyzing cellulose using 5.0 wt% Pd / C in an H 2 / CO 2 (2.9 / 0.1 MPa) atmosphere:

[0174] In this comparative example, the steps of the hydrogenolysis and depolymerization process of cellulose catalyzed by Pd / C were the same as those in Example 8, except that the reaction atmosphere was replaced with H 2 / CO2 = 2.9 / 0.1 MPa. Cellulose (0.5 g), 5.0 wt% Pd / C catalyst (0.2 g), deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0175] After testing, the cellulose conversion rate under this reaction condition was 74.2%, and the yields and selectivities of the product ketone compounds were 4.1% and 5.5% respectively. The other products were mainly alcohols and acids. The yields and selectivities of the alcohol compounds were 37.2% and 50.1% respectively, and the yields and selectivities of the acid compounds were 8.1% and 10.9% respectively. The total yields and selectivities of the ketone, alcohol and acid products were 49.4% and 66.6% respectively. The reaction results are listed in Table 2.

[0176] Comparative Example 3

[0177] The reaction atmosphere in the comparative example used H 2 / CO 2 (1.5 / 1.5 MPa).

[0178] The method for catalytically depolymerizing cellulose using 5.0 wt% Pd / C in H 2 / CO 2 (1.5 / 1.5 MPa) atmosphere in this comparative example:

[0179] In this example, the steps of the Pd / C-catalyzed hydrogenolysis and depolymerization of cellulose were the same as those in Example 8, except that the reaction atmosphere was replaced with H 2 / CO 2 = 1.5 / 1.5 MPa. Cellulose (0.5 g), 5.0 wt% Pd / C catalyst (0.2 g), deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0180] After testing, the cellulose conversion rate under this reaction condition was 76.8%, and the yields and selectivities of the main product ketone compounds were 5.8% and 7.6% respectively. The other products were mainly alcohols and acids. The yields and selectivities of the alcohol compounds were 26.3% and 34.2% respectively, and the yields and selectivities of the acid compounds were 9.2% and 12.0% respectively. The total yields and selectivities of the ketone, alcohol and acid products were 41.3% and 53.8% respectively. The test results are shown in Table 2.

[0181] Comparative Example 4

[0182] The reaction atmosphere in this comparative example did not use a mixed gas, but only used high-purity hydrogen.

[0183] The method for catalytically depolymerizing cellulose using 5.0 wt% Pd / C in pure H 2 atmosphere in this comparative example:

[0184] In this comparative example, the procedure for the hydrocatalytic depolymerization of cellulose using Pd / C was the same as in Example 8, except that the reaction atmosphere was replaced with pure H₂ 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.

[0185] After testing, the conversion rate of cellulose under these reaction conditions was 75.9%, the yields and selectivities of the product ketone compounds were 5.6% and 7.4% respectively, and the other products were mainly alcohols and acid products. The yields and selectivities of the alcohol compounds were 41.8% and 55.1% respectively, and 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. The test results are shown in Table 2.

[0186] Comparative Example 5

[0187] In this comparative example, the reaction atmosphere did not use a mixed gas, only high-purity CO was used.

[0188] The method for catalyzing cellulose using 5.0 wt% Pd / C under a high-purity CO atmosphere in this comparative example:

[0189] In this comparative example, the procedure for the hydrocatalytic depolymerization of cellulose using Pd / C was the same as in Example 8, 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.

[0190] After testing, the conversion rate of cellulose under these reaction conditions was 48.9%, the yields and selectivities of the product ketone compounds were 4.6% and 9.4% respectively, and the other products were mainly alcohols and acid products. The yields and selectivities of the alcohol compounds were 9.2% and 18.8% respectively, and the yields and selectivities of the acid compounds were 5.4% and 11.0% respectively. The total yields and selectivities of the ketone, alcohol, and acid products were 19.2% and 39.3% respectively. The test results are shown in Table 2.

[0191] Comparative Example 6

[0192] In this comparative example, the reaction atmosphere did not use a mixed gas, only high-purity H₂ was used. 2 .

[0193] The method for catalyzing cellulose using 1.0 wt% Pd / C under a pure H₂ 2 atmosphere in this comparative example:

[0194] In this comparative example, the procedure for the hydrogenolysis of cellulose catalyzed by Pd / C is the same as that in Example 8, except that the reaction atmosphere is replaced with pure H₂ at 3.0 MPa. 2 , and the catalyst is replaced with 1.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g) and deionized water (20.0 mL) are heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0195] After testing, the conversion rate of cellulose under this reaction condition is 32.3%. No ketone compounds are detected. The yields and selectivities of alcohol compounds are 14.4% and 44.6% respectively, and the yields and selectivities of acid compounds are 1.7% and 5.3% respectively. The total yields and selectivities of ketone, alcohol, and acid products are 16.1% and 49.8% respectively. The test results are shown in Table 2.

[0196] Comparative Example 7

[0197] In this comparative example, the reaction atmosphere does not use a mixed gas, but only uses high-purity CO.

[0198] The method for catalyzing cellulose with 1.0 wt% Pd / C in a pure CO atmosphere in this comparative example:

[0199] In this comparative example, the procedure for the hydrogenolysis of cellulose catalyzed by Pd / C is the same as that in Example 8, except that the reaction atmosphere is replaced with pure CO at 3.0 MPa, and the catalyst is replaced with 1.0 wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g) and deionized water (20.0 mL) are heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0200] After testing, the conversion rate of cellulose under this reaction condition is 22.6%. The yields and selectivities of the ketone compounds in the products are 0.9% and 4.0% respectively. The other products are mainly alcohol and acid products. The yields and selectivities of alcohol compounds are 3.1% and 13.7% respectively, and the yields and selectivities of acid compounds are 0.7% and 3.1% respectively. The total yields and selectivities of ketone, alcohol, and acid products are 4.7% and 20.8% respectively. The test results are shown in Table 2.

[0201] Comparative Example 8

[0202] In this comparative example, the reaction atmosphere does not use a mixed gas, but only uses high-purity H₂ 2 .

[0203] The method for catalyzing cellulose with 30.0 wt% Pd / C in a pure H₂ 2 atmosphere in this comparative example:

[0204] In this comparative example, the procedure for the hydrogenolysis of cellulose catalyzed by Pd / C is the same as that in Example 8, except that the reaction atmosphere is replaced with pure H₂ at 3.0 MPa.2 , the catalyst was replaced with a 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.

[0205] After testing, the cellulose conversion rate under this reaction condition was 84.5%, and 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, and 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. The test results are shown in Table 2.

[0206] Comparative Example 9

[0207] In this comparative example, the reaction atmosphere did not use a mixed gas, but only high-purity CO.

[0208] The method for catalytically hydrogenating and depolymerizing cellulose with 30.0 wt% Pd / C in a pure CO atmosphere in this comparative example:

[0209] In this comparative example, the steps of the Pd / C-catalyzed cellulose hydrocracking and depolymerization process were the same as those in Example 8, 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) and deionized water (20.0 mL) were heated to 230.0 °C in a reaction kettle and reacted for 2.0 h.

[0210] After testing, the cellulose conversion rate under this reaction condition was 76.5%, and the yields and selectivities of the product ketone compounds were 7.2% and 9.4% respectively. The other products were mainly alcohol and acid products. 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 test results are shown in Table 2.

[0211] Table 2

[0212]

[0213]

[0214] As can be seen from Table 2, in the present invention, the Pd loading is 1-20 wt%, and the hydrogen source gas containing CO and CO 2 is mainly composed of H 2 , CO and CO 2 and CO and CO 2Under the condition that the volume percentage content is 20% to 67%, the cellulose conversion rate and the yield of ketone compounds in the examples are significantly higher than those of pure H 2 and pure CO. Under different reaction atmospheres (H with initial partial pressures of 0 - 3.0 MPa respectively 2 , CO and CO 2 , while keeping the total pressure at 3.0 MPa), it can be seen from Comparative Examples 1 - 2 and Examples 8 - 20 that in pure H 2 atmosphere, the conversion rate of cellulose is 75.9%, the highest yield of non - main product alcohol is 41.8%, and the yield of ketone compounds is only 5.6%. When the partial pressures of CO and CO 2 are increased, the yield of alcohol compounds begins to decrease, while the yield of ketone compounds begins to increase. When H 2 / CO / CO 2 is 0.5 / 1.0 / 1.5 MPa, the yield of ketone compounds is 38.7%. This may be because CO inhibits the excessive hydrogenation of C = O in ketone compounds to alcohol and the increased hydrolysis rate of CO 2 . Continuing to increase the partial pressure of CO or CO 2 , the yields of both ketone compounds and alcohol compounds begin to decrease, probably because H 2 is insufficient, and too much CO is adsorbed on Pd, resulting in insufficient catalytic active sites and reducing the hydrocracking / hydrogenation ability. When the reaction atmosphere is pure CO, the reaction effect is 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, CO 2 and H 2 will play a synergistic role to promote the conversion of cellulose and the formation of ketone compounds. An appropriate amount of H 2 , CO and CO 2 mixed gas helps to improve the catalytic effect.

[0215] It should be noted that normal hydrogen source gases more or less contain CO and CO 2 , as shown in Table 2, most of the H 2 is produced through the water - gas shift reaction, and it is not easy to remove CO and CO 2 , and it is even more difficult to completely remove them. In the present invention, a supported Pd / C catalyst is used to carry out catalytic hydrocracking and hydrogenation reactions in a non - pure hydrogen atmosphere containing CO and CO 2 , and the CO and CO contained in the hydrogen source gas of the present invention 2 have a relatively large content range, and the CO and CO 2The volume percentage in the reaction atmosphere ranging from 20% to 67% can achieve the hydrocracking of cellulose to obtain ketone compounds, effectively reducing the reaction cost, and higher cellulose conversion rate and selectivity of ketone compounds are obtained. The present invention provides a feasible way for the efficient conversion of cellulose.

[0216] 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 included in the protection scope of the present invention.

Claims

1. A method for preparing ketone compounds by catalytic hydrogenation of cellulose in a crude hydrogen atmosphere, 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 230-260° C. in a hydrogen source gas containing carbon monoxide and carbon dioxide to obtain a product mainly composed of ketone compounds. The volume percentage content of carbon monoxide and carbon dioxide in the hydrogen source gas containing carbon monoxide and carbon dioxide is 20% to 67%; and the Pd loading amount in the catalyst is 1-20wt%.

2. The method for preparing ketone compounds by catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere according to claim 1, characterized in that: The Pd loading in the catalyst is 3-10wt%.

3. The method for preparing ketone compounds by catalytic hydrogenation of cellulose based on crude hydrogen atmosphere 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 catalytic hydrogenation of cellulose based on crude hydrogen atmosphere according to claim 1, characterized in that: The volume percentage contents of carbon monoxide and carbon dioxide in the hydrogen source gas containing carbon monoxide and carbon dioxide are both 33.3-50%.

5. The method for preparing ketone compounds by catalytic hydrogenation of cellulose based on crude hydrogen atmosphere 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 catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere 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 catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere 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 catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere 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 catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere according to claim 1, characterized in that: The cellulose is microcrystalline cellulose and / or natural cellulose.

10. The method for preparing ketone compounds by catalytic hydrogenation of cellulose in a crude hydrogen atmosphere 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 catalytic hydrogenation of cellulose based on crude hydrogen atmosphere 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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