A method for preparing ketone compounds by catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere

Abstract

The application discloses a method for preparing ketone compounds by catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere. The method uses cellulose as a raw material, water as a solvent, and activated carbon loaded Pd as a catalyst. The total pressure of the hydrogen source gas containing carbon monoxide and carbon dioxide is 0.5-4.0 MPa, the temperature is 230-260 DEG C, and the reaction time is 1-6 h, so that ketone compounds are obtained as main products. The volume percentage content of carbon monoxide and carbon dioxide in the hydrogen source gas containing carbon monoxide and carbon dioxide is 20%-67%. The reaction provided by the application has the characteristics of renewable raw materials, low reaction process cost, environmental friendliness, mild reaction conditions, high product selectivity, and high economic value of product added value.

Description

TECHNICAL FIELD

[0001] The present application relates to the preparation of ketones, in particular, a one-pot synthesis of ketones with H2 / CO / CO2 as the reaction atmosphere and cellulose as the raw material. BACKGROUND

[0002] Cellulose is a high polymer of glucose polymerized by glycosidic bond, as shown in the following formula (a). It is a feasible way for cellulose conversion to depolymerize it into small molecular weight platform molecules and then convert them into other important chemicals.

[0003]

[0004] Cellulose hydrogenation reaction mainly refers to the process of converting polysaccharide cellulose into other useful chemicals through hydrogenation reaction, which belongs to the category of reduction reaction. Palladium (Pd) has been used as a catalyst in various catalytic hydrogenation reactions, but there are still two problems in using Pd as a catalyst for catalytic hydrogenation reaction: on the one hand, due to the strong hydrogenation performance of Pd, it will perform non-selective hydrogenation on all functional groups in compounds containing multiple hydrogenation functional groups (such as -C=C, -C≡C, -C=O, etc.). On the other hand, Pd is easily poisoned by carbon monoxide (CO), which makes the purity requirement of hydrogen (H2) used in the hydrogenation process very high, at least the purity of hydrogen should be higher than 99.99%.

[0005] Biomass-derived ketones are an important class of platform molecules, which 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 the synthesis of specific fragrances and flavors used in perfumes, cosmetics and food. 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 synthesized into a series of high-end chemical products through chemical conversion, which are used for energy, food, medicine and other purposes. HD is an important chemical for the synthesis of 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, which is an important platform for generating various high-value chemicals and fuels. In general, 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 working to develop new and efficient catalytic hydrogenation systems for this reaction.

[0006] Currently, the industrial hydrogen production mostly adopts the natural gas steam reforming reaction process route. This process not only has low cost but also has high technical maturity; however, the gas produced by this process mainly contains H2, CO and CO2, as shown in Table 1. The entire hydrogen production process of this mode can be divided into four steps:

[0007] Table 1

[0008]

[0009] Firstly, the raw material pretreatment stage, untreated natural gas usually contains a certain amount of impurities, such as hydrogen sulfide (H2S), carbon dioxide (CO2), moisture and other trace amounts of organic sulfides, etc. In order to avoid the toxic effects of these impurities on the subsequent reforming catalyst, it is necessary to pretreat the natural gas. This stage mainly removes impurities through desulfurization, decarburization and drying processes to make the natural gas meet the purity standards required for the reforming reaction. After pretreatment, the main component of the natural gas, methane (CH4), is usually about 95%, and other impurities are controlled at a very low level, for example, the hydrogen sulfide content can be reduced to below 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 pretreated natural gas is mixed with steam and enters the reforming reactor. In the reactor, under the action of high temperature (usually 700-900°C) and catalyst, the steam reforming reaction of methane occurs. The main chemical equation of this reaction is: CH4+H2O→CO+H2. This reaction is carried out at a relatively low temperature of 200-500°C, and generally uses iron-based or ketone-based catalysts. After the steam reforming reaction, the hydrogen (H2) content in the gas is increased to 40%-60%, the carbon monoxide (CO) content is increased to 10%-20%, the carbon dioxide (CO2) content is increased to about 20%-30%, the methane (CH4) is reduced to 10-15%, and the steam (H2O) content is also 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 from the steam reforming reactor enters the water gas shift reaction. In this reaction, CO and H2O further react to form CO2 and H2 (CO+H2O→H2+CO2). The water gas shift reaction is usually carried out at a relatively low temperature (200-500°C), and generally uses iron-based or copper-based catalysts. This reaction is a reversible reaction, and the equilibrium and product composition of the reaction are adjusted by controlling the reaction temperature, pressure and reactant concentration. After the water gas shift reaction, the H2 content in the gas is further increased to 60-80%, the CO content is reduced to 5-10%, and the CO2 content is reduced to 18-25%. The cost of this step accounts for 10-15%.

[0012] The last stage is gas purification. The synthesis gas after the above reaction steps still contains a small amount of impurities, such as unreacted carbon dioxide (CO2), carbon monoxide (CO), etc. In order to meet the strict requirements of subsequent industrial applications for the purity of synthesis gas, 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 carbon dioxide and other impurities can be separated out for recycling. The cost of this step accounts for 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 increases the cost of catalytic hydrogenation reactions in industry.

[0014] Chinese invention patent CN109896938B discloses a method for preparing 2,5-hexanedione. The method uses liquid acid and supported noble metal to coordinate catalytic biomass conversion to obtain 2,5-hexanedione. However, the liquid acid such as hydrochloric acid used in this technology still has problems of corrosion and recovery, and the use of noble metal catalyst also increases the cost of generating 2,5-hexanedione.

[0015] Chinese invention patent CN115259995B discloses a method for preparing vicinal diols by catalytic hydrogenolysis of lignocellulose. The method uses a magnetic metal catalyst wrapped in a graphene-like carbon shell, which efficiently converts lignocellulose into vicinal diols under specific reaction conditions (such as a reaction temperature of 120-220℃, a reaction time of 2-4 hours, and a hydrogen pressure of 5.5MPa). Although this technology can efficiently prepare diols, it requires a large amount of high-purity hydrogen, resulting in high production costs and making it difficult to industrialize. Moreover, high-purity hydrogen is required for hydrogenolysis of cellulose and even the entire biomass. SUMMARY

[0016] In view of the problems existing in the prior art, the present application aims to provide a method for preparing ketone compounds by catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere, which has mild reaction conditions, is environmentally friendly, and is catalytically efficient, with a ketone compound yield of 10.6-42.5%. The method can perform catalytic hydrogenation reactions under a non-pure hydrogen atmosphere, significantly reducing the cost of catalytic hydrogenation reactions.

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

[0018] The application discloses a method for preparing ketone compounds by catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere, and is characterized in that: cellulose is used as raw material, water is used as solvent, and Pd supported on activated carbon is used as catalyst; the ketone compounds are obtained as main products by reacting for 1-6 hours under the total pressure of 0.5-4.0 MPa of hydrogen source gas containing carbon monoxide and carbon dioxide and the temperature of 230-260 DEG C; the volume percentage content of carbon monoxide and carbon dioxide in the hydrogen source gas containing carbon monoxide and carbon dioxide is 20%-67%; and the Pd loading in the catalyst is 1-20 wt%.

[0019] To further realize the purpose of the application, preferably, the Pd loading in the catalyst is 3-10 wt%.

[0020] Preferably, the mass ratio of the cellulose to the catalyst is 1:0.2-1:0.6, and the mass ratio of the 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%.

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

[0023] 1) dissolving a Pd source precursor in a solvent, adding ammonia water and water, and stirring to form solution A;

[0024] 2) stirring to add water, alkali and carbon black powder into solution A to form liquid B;

[0025] 3) performing ultrasonic treatment on liquid B, adding a reducing agent under stirring, heating to 20-90 DEG C, and reacting for 0.5-6 hours; performing suction filtration, washing and vacuum drying treatment on the reaction product to obtain the Pd / C catalyst; and the reducing agent is at least one of NaBH4, vitamin C and formaldehyde.

[0026] Preferably, in step 1, the Pd source precursor is 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 solution A is 1x10 -4 ~ 1x10 -1 mol / L; and the molar ratio of the Pd source precursor to ammonia water is 1:10-50.

[0027] Preferably, in step 2, the alkali is at least one of NaOH and KOH; the molar volume concentration of the alkali 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), wherein the volume unit is ml and the mass unit is mg.

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

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

[0030] Preferably, the ketone compound-based product includes one or more of ketone compounds, alcohol compounds and acid compounds.

[0031] Preferably, 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-cyclopenten-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.

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

[0033] The CO in the present application can inhibit excessive hydrogenation of the product C=O, and the CO2 in the high-temperature water can release H + (CO2(aq)+H2O→H + +HCO3 - →2H + +CO3 2- ) to accelerate the hydrolysis reaction, and the CO in the reaction can undergo water gas shift reaction (WGSR) (CO+H2O→H2+CO2) to generate H2 and CO2, which can further promote the hydrogenolysis and hydrolysis reactions.

[0034] The reaction provided by the present application has the characteristics of renewable raw materials, low reaction process cost, environmental friendliness, mild reaction conditions, high product selectivity, high economic value of product added value, etc., and provides an effective way for preparing ketone compounds from biomass.

[0035] The present application develops a novel hydrogenolysis strategy to replace the traditional hydrogenolysis technology, and provides a sustainable and cost-effective biomass utilization method. BRIEF DESCRIPTION OF DRAWINGS

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

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

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

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

[0040] For a better understanding of the present application, the following further describes the present application in conjunction with the accompanying drawings and examples, but the embodiments of the present application are not limited thereto.

[0041] The present application is mainly directed to the problem that high-purity hydrogen needs to be used in the hydrogenolysis process of cellulose and even biomass. In the current research and industry, all the hydrogenolysis processes of biomass need to use high-purity hydrogen, which greatly increases the industrial cost. Through the research on the hydrogenolysis reaction of cellulose under different reaction atmospheres, the present application finds that when a Pd / C supported catalyst is used to catalyze the hydrogenation reaction, the hydrogen source gas for providing hydrogen elements in the catalytic hydrogenation reaction contains CO and CO2, and the volume percentage of CO and CO2 can be in a very large range of 20% to 67%, and the Pd / C supported catalyst can efficiently catalyze the hydrogenolysis of cellulose to prepare ketone compounds. Specifically, the present application provides a method for preparing ketone compounds by catalytic hydrogenation of cellulose under a crude hydrogen atmosphere: taking cellulose as a raw material, water as a solvent, and activated carbon supported Pd as a catalyst, and reacting for 1-6 h under a total pressure of 0.5-4.0 MPa of a hydrogen source gas containing CO and CO2 and a temperature of 150-260℃ to obtain a product mainly containing ketone compounds; the hydrogen source gas containing CO and CO2 mainly consists of H2, CO and CO2, and the volume percentage of CO and CO2 is 20%-67%; and the Pd loading in the catalyst is 1-20wt%.

[0042] The present application uses crude hydrogen (containing CO and CO2) as a hydrogen source, and it is found that the hydrogen source containing CO and CO2 not only has no negative effect on the reaction, but also promotes the reaction:

[0043] (1) CO can inhibit excessive hydrogenation, avoid the hydrogenation of -C=O, and thus produce high-value ketone compounds with high selectivity, wherein the ketone compounds mainly include 2,5-hexanedione and 1-hydroxy-2-hexanone, etc.

[0044] (2) the solvent of the reaction system is water, CO2 will continue to react with water at high temperature to generate H2CO3, H2CO3 decomposes to produce H + (CO2(aq) + H2O → H2CO3 → H + + HCO3 - , providing acidic conditions for the reaction, promoting the hydrolysis reaction. Therefore, CO2 in the reaction atmosphere will promote the hydrolysis reaction, and CO in the reaction atmosphere will undergo WGSR with H2O to produce H2 and CO2, further promoting hydrogenolysis and hydrolysis reaction, thus increasing the yield of ketones in the product.

[0045] The main way of industrial hydrogen production is currently natural gas steam reforming, and the gas content of each step is shown in Table 1 above, so the industrial significance of using H2 containing CO and CO2 as the reaction atmosphere is to provide a wider selection for the reaction atmosphere of the industrialization of cellulose hydrogenolysis, thereby greatly reducing the industrialization cost. The main role of CO in the reaction is to inhibit excessive hydrogenation, because the CO2 produced by WGSR is not enough, so the hydrolysis reaction is not enough, therefore, the additional CO2 can make up for the shortage of CO2, which leads to insufficient hydrolysis reaction, compared with the best result of H2 / CO atmosphere, the ketone yield of H2 / CO / CO2 is obviously improved, 37.8 vs 42.5%.

[0046] The raw material of the reaction of the present application is cellulose, and the hydrogen source gas containing CO and CO2 directly or indirectly provides hydrogen species and acidic environment for the reaction. Cellulose is first reacted under hydrothermal conditions to generate glucose, which undergoes a multi-step reaction, including ring opening to generate 1-hydroxy-2-butanone (HB), hydrogenation deoxygenation to generate 1-hydroxy-2-hexanone (HHO), and isomerization to generate fructose. Fructose is dehydrated to generate 5-hydroxymethylfurfural (HMF), and then a series of reactions such as hydrogenation, hydrolysis, etc. to generate 2,5-hexanedione and other products.

[0047] The preparation method of the active carbon supported Pd catalyst of the present application adopts liquid phase chemical reduction method, and ammonia is used as complexing agent to make Pd ions first form stable complex ions in liquid phase, and then reduced on carbon powder by reducing agent.

[0048] The reagents, materials, etc. used in the following examples are commonly used raw materials in the art, which can be obtained from commercial channels unless otherwise specified.

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

[0050] 1. 0.02 g PdCl2 was added into 0.1 M H2PdCl4 solution prepared by HCl, then 5.0 mL water was added, after stirring uniformly, 0.4 mL ammonia water was added, and magnetic stirring was carried out until the solution became colorless and transparent; the molar volume concentration of H2PdCl4 in the solution was 1.8 x 10-3 M, and the molar ratio of H2PdCl4 to ammonia water was 1:22; -2 M, the molar ratio of H2PdCl4 to ammonia water was 1:22;

[0051] 2. 30.0 mL ultrapure water was added into the flask, then 1.5 mL of 1.0 M NaOH solution was added, and magnetic stirring was carried out for 20.0 min;

[0052] 3. 0.9 g carbon black powder was added into the flask, and ultrasonic treatment was carried out for 30.0 min under 100 W power, then the flask was transferred into an oil bath, and magnetic stirring was carried out for 2.0 h under Ar gas atmosphere;

[0053] 4. Then 1 mL of formaldehyde solution was added into the flask under magnetic stirring, and stirring was carried out for 10.0 min; the molar ratio of Pd to formaldehyde was 1:115.5;

[0054] 5. The above mixture was heated to 60.0 °C at a heating rate of 2.0 °C / min, and constant temperature reaction was carried out for 2.0 h at this temperature;

[0055] 6. The obtained reaction product was suction filtered, and washed with ultrapure water for 4 times, and dried in a vacuum drying box at 80.0 °C for 4.0 h, to obtain Pd / C catalyst. The mass fraction of Pd in the obtained catalyst was 1.0 wt%.

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

[0057] 1. 0.02 g Na2PdCl4 was added into 0.1 M Na2PdCl4 solution prepared by ultrapure water, then 5.0 mL water was added, after stirring uniformly, 0.4 mL ammonia water was added, and magnetic stirring was carried out until the solution became colorless and transparent; the molar volume concentration of Na2PdCl4 in the solution was 1.8 x 10-3 M, and the molar ratio of Na2PdCl4 to ammonia water was 1:22; -2 M, the molar ratio of Na2PdCl4 to ammonia water was 1:22;

[0058] 2. 30.0 mL ultrapure water was added into the flask, then 1.5 mL of 1.0 M NaOH solution was added, and magnetic stirring was carried out for 20.0 min;

[0059] 3. 0.9 g carbon black powder was added into the flask, and ultrasonic treatment was carried out for 30.0 min under 100 W power, then the flask was transferred into an oil bath, and magnetic stirring was carried out for 2.0 h under Ar gas atmosphere;

[0060] 4. Then, 1 mL of formaldehyde solution was added to the flask under magnetic stirring for 10.0 min; the molar ratio of Pd to formaldehyde was 1:115.5;

[0061] 5. The above mixture was heated to 60.0°C at a heating rate of 2.0°C / min, and kept at this temperature for 2.0 h;

[0062] 6. The obtained reaction product was filtered under suction and washed with ultrapure water for 4 times, and dried 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 was 1.0 wt%.

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

[0064] 1. 0.02 g of K2PdCl4 was added to ultrapure water to prepare a 0.1 M K2PdCl4 solution, then 5.0 mL of water was added, and after stirring uniformly, 0.4 mL of ammonia water was added, and the solution was stirred magnetically until it became colorless and transparent; the molar volume concentration of K2PdCl4 in the solution was 1.8×10 -2 M, and the molar ratio of K2PdCl4 to ammonia water was 1:22;

[0065] 2. 30.0 mL of ultrapure water was added to the flask, then 1.5 mL of 1.0 M NaOH solution was added, and the solution was stirred magnetically for 20.0 min;

[0066] 3. 0.9 g of carbon black powder was added to the flask, and ultrasonic was performed at a power of 100 W for 30.0 min, then the flask was transferred to an oil bath, and stirred magnetically under Ar atmosphere for 2.0 h;

[0067] 4. Then, 1 mL of formaldehyde solution was added to the flask under magnetic stirring for 10.0 min; the molar ratio of Pd to formaldehyde was 1:115.5;

[0068] 5. The above mixture was heated to 60.0°C at a heating rate of 2.0°C / min, and kept at this temperature for 2.0 h;

[0069] 6. The obtained reaction product was filtered under suction and washed with ultrapure water for 4 times, and dried 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 was 1.0 wt%.

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

[0071] 1. 0.02 g K2PdCl4 was added to ultrapure water to prepare a 0.1 M K2PdCl4 solution, then 5.0 mL of water was added, and after stirring until uniform, 0.4 mL of ammonia water was added, and magnetic stirring was performed until the solution became colorless and transparent; the molar volume concentration of K2PdCl4 in the solution was 1.8 x 10-3 M, and the molar ratio of K2PdCl4 to ammonia water was 1:22; -2 M, the molar ratio of K2PdCl4 to ammonia water was 1:22;

[0072] 2. 30.0 mL of ultrapure water was added to the flask, then 1.5 mL of 1.0 M NaOH solution was added, and magnetic stirring was performed for 20.0 min;

[0073] 3. 0.9 g of carbon black powder was added to the flask, and ultrasonic treatment was performed at a power of 50 W for 120.0 min, then the flask was transferred to an oil bath, and magnetic stirring was performed under an Ar gas atmosphere for 1.0 h;

[0074] 4. Then 10 mL of 0.1 M KBH4 solution was added to the flask under magnetic stirring, and stirring was performed for 10.0 min; the molar ratio of Pd to KBH4 was 1:8.4;

[0075] 5. The above mixture was heated to 20.0°C at a heating rate of 4.0°C / min, and constant temperature reaction was performed at this temperature for 6.0 h;

[0076] 6. The reaction product obtained was suction filtered, washed with ultrapure water 4 times, and dried in a vacuum drying oven at 80.0°C for 4.0 h to obtain a Pd / C catalyst. The mass fraction of Pd in the obtained catalyst was 1.0 wt%.

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

[0078] 1. 0.02 g PdCl2 was weighed into a flask, and HCl was added to prepare a 0.1 M H2PdCl4 solution, then 5.0 mL of water was added, and after stirring until uniform, 0.4 mL of ammonia water was added, and magnetic stirring was performed until the solution became colorless and transparent; the molar volume concentration of H2PdCl4 in the solution was 1.8 x 10-3 M, and the molar ratio of H2PdCl4 to ammonia water was 1:22; -2 M, the molar ratio of K2PdCl4 to ammonia water was 1:22;

[0079] 2. 30.0 mL of ultrapure water was added to the flask, then 1.5 mL of 1.0 M NaOH solution was added, and magnetic stirring was performed for 20.0 min;

[0080] 3. 0.2 g of carbon black powder was added to the flask, and ultrasonic treatment was performed at a power of 100 W for 30.0 min, then the flask was transferred to an oil bath, and magnetic stirring was performed under an Ar gas atmosphere for 2.0 h;

[0081] 4. Then, 1 mL of formaldehyde solution was added to the flask under magnetic stirring for 10.0 min; the molar ratio of Pd to formaldehyde was 1:115.5;

[0082] 5. The above mixture was heated to 90.0°C at a heating rate of 7.0°C / min, and kept at this temperature for 0.5 h;

[0083] 6. The obtained reaction product was filtered and washed with ultrapure water for 4 times, and dried in a vacuum drying oven at 80.0°C for 4.0 h to obtain Pd / C catalyst, Figure 1 is a TEM image of 5wt% Pd / C in Example 5. As shown in Figure 1 , the dispersibility of Pd in carbon black is good, and the particle size is uniform. The mass fraction of Pd in the obtained catalyst is 5.0wt%, Figure 2 is a particle size distribution diagram of 5wt% Pd / C in Example 5. As shown in Figure 2 , the particle size of Pd is about 8.0 nm.

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

[0085] 1. 0.1 g of PdCl2 was weighed into a flask, and 25.0 mL of water was added to prepare a 0.1M H2PdCl4 solution. After stirring uniformly, 2 mL of ammonia water was added, and the solution was stirred magnetically until it became colorless and transparent; the molar volume concentration of H2PdCl4 in the solution was 1.8×10 -2 M, and the molar ratio of H2PdCl4 to ammonia water was 1:22;

[0086] 2. 150.0 mL of ultrapure water was added to the flask, followed by 7.5 mL of 1.0M NaOH solution, and the mixture was stirred magnetically for 20.0 min;

[0087] 3. 1.0 g of carbon black powder was added to the flask, and ultrasonic was performed at a power of 150W for 5.0 min. Then, the flask was transferred to an oil bath, and stirred magnetically under Ar atmosphere for 4.0 h;

[0088] 4. Then, 5 mL of formaldehyde solution was added to the flask under magnetic stirring for 10.0 min; the molar ratio of Pd to formaldehyde was 1:115.5;

[0089] 5. The above mixture was heated to 20.0°C at a heating rate of 4.0°C / min, and kept at this temperature for 6.0 h;

[0090] 6. The obtained reaction product was filtered and washed with ultrapure water for 4 times, and dried in a vacuum drying oven at 80.0°C for 4.0 h to obtain Pd / C catalyst,Figure 1 As shown, the Pd / C catalyst has a rough, irregular morphology. As shown, the Pd is well dispersed in the carbon black, and the particle size is uniform. The Pd content of the obtained catalyst was 5.0wt%, and the Pd particle size was about 8.0nm. Figure 2

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

[0092] 1. 0.02g of PdCl2 was weighed into a flask, and 5.0mL of water was added. After stirring until uniform, 0.4mL of ammonia water was added, and magnetic stirring was performed until the solution was colorless and transparent. The molar volume concentration of H2PdCl4 in the solution was 1.8x10-4mol / L, and the molar ratio of H2PdCl4 to ammonia water was 1:22. -2

[0093] 2. 30.0mL of ultrapure water was added to the flask, followed by 1.5mL of 1.0M NaOH solution, and magnetic stirring was performed for 20.0min.

[0094] 3. 400mg of carbon black powder was added to the flask, and ultrasonic treatment was performed for 30.0min at a power of 100W. Then the flask was transferred to an oil bath, and magnetic stirring was performed for 2.0h under an Ar gas atmosphere.

[0095] 4. Then 26.5mL of formaldehyde solution was added to the flask under magnetic stirring, and stirring was performed for 10.0min. The molar ratio of Pd to formaldehyde was 1:115.5.

[0096] 5. The above mixture was heated to 60.0℃ at a heating rate of 2.0℃ / min, and constant temperature reaction was performed at this temperature for 2.0h.

[0097] 6. The obtained reaction product was suction filtered, washed with ultrapure water 4 times, and dried in a vacuum drying oven at 80.0℃ for 4.0h to obtain a Pd / C catalyst. The Pd content of the obtained catalyst was 30.0wt%.

[0098] Example 8: Method for selectively preparing ketone compounds from cellulose using 5.0wt% Pd / C under a H2 / CO / CO2(0.5 / 1.0 / 1.5MPa) gas atmosphere:

[0099] ​​Cellulose was dried, 0.5 g of cellulose, 0.2 g of 5.0 wt% Pd / C catalyst, and 20.0 mL of water solution were mixed in a 50.0 mL high-pressure reactor, the reactor was replaced with high-purity argon three times, and then filled with 3.0 MPa of H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa). The reactor was heated to 230.0°C, and reacted for 2.0 h. After the reaction was completed, the reactor was cooled to room temperature, the reaction mixture was filtered, and then extracted with dichloromethane (DCM) to enrich volatile products (5.0 mL x 5 times). The water phase and dichloromethane phase were obtained. The residue was washed with tetrahydrofuran five times (5.0 mL x 5 times) and then dried at 60.0°C under vacuum for 12.0 h. The conversion rate of cellulose was calculated by weighing. The water phase (containing water-soluble products such as acids and alcohols) was subjected to vacuum distillation at 45.0°C to remove methanol, and the collected solution was diluted with ultrapure water to 50.0 mL. The water phase product was subjected to qualitative analysis by liquid chromatography-mass spectrometry (HPLC-MS). The chromatographic column was HPX-87H sugar column (300 mm x 7.8 mm, 5 μm), the refractive index detector (RID) was used, the detector temperature was 50.0°C, the mobile phase was 5.0 mM H2SO4, the flow rate was 0.6 mL min -1 , and the column temperature was 65.0°C.

[0100] The components were quantitatively analyzed by using the characterization curve method. The dichloromethane phase (containing volatile products such as ketones) was added with dimethyl phthalate (internal standard) and diluted with dichloromethane to 25.0 mL. Qualitative analysis was performed by gas chromatography-mass spectrometry (GC-MS), and quantitative determination was performed by GC. The chromatographic column was HP-5MS 5% phenyl methyl silox capillary column (30 m x 0.25 μm x 0.25 μm), the injection port temperature was 270.0°C, the flame ionization detector (FID) was used, the detector temperature was 270.0°C, the carrier gas was He, the flow rate was 1.0 mL min -1 , and the column temperature was a temperature rising program, the initial column oven temperature was 50.0°C (maintained for 3.0 min), the temperature was raised to 270.0°C at a rate of 15.0°C min -1 (min) (maintained for 1 min). During the operation, the auxiliary temperature was maintained at 280.0°C, and the split ratio was 10:1. The qualitative analysis conditions are shown in Figure 3 and Figure 4 , and Figure 3 is the FID spectrum (gas chromatogram) of the product obtained by depolymerization of cellulose in Example 8. Figure 4is the HPLC (high performance liquid chromatography) profile of the product obtained by cellulose depolymerization in Example 8; by analyzing the detection, two types of products, ketone and alcohol, appeared at different retention times, in which 1-hydroxy-2-hexanone, 2-hydroxy-3-hexanone, ethyl propionate, 2-methyl-2-cyclopentene and 2,5-hexanedione with the largest peak area were main products.

[0101] The cellulose conversion rate Conversion (%) was calculated by the remaining solid dry weight, as shown in Formula 1. The 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] wherein m1 is the mass of the original cellulose, m2 is the mass of the unreacted raw material collected by filtration, washing and drying, i refers to a product, n i is the molar mass of product i, k i is the number of carbon atoms 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 i is the molar mass of 2,5-hexanedione, k i is the number of carbon atoms in 2,5-hexanedione.

[0104] It was tested that under the action of Pd / C catalyst, the unreacted raw material (m2) after reaction was 0.044 g, and the remaining solid dry weight calculation method (Formula 1) was used:

[0105]

[0106] The conversion rate of cellulose was 91.2%, and the yield of liquid product was calculated by Formula 2, such as the yield of 1-hydroxy-2-hexanone and 2,5-hexanedione was calculated by the calculation method (Formula 2):

[0107]

[0108] The same method was used to calculate the 2-methylcyclopentanone, 2-hydroxy-3- hexanone, 2-methyl-2-cyclopenten-1-one, 1.9%, 9.2% and 9.1%, thus the total yield of product ketones was 42.5%, the product selectivity of ketones was calculated by formula 3 as 46.6%, other products were mainly alcohol (pentanol, tetrahydrofurfuryl alcohol and 1,2-hexanediol) and acid (pentanoic acid) products, the yield and selectivity of alcohol products were 15.1% and 16.6% respectively, the yield and selectivity of acid products were 7.2% and 7.9% respectively, the total yield and selectivity of ketone, alcohol and acid products were 64.8% and 71.1% respectively, the test results are shown in Table 2.

[0109] Example 9: Method of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(2.0 / 0.5 / 0.5MPa) atmosphere:

[0110] The Pd / C catalyzing cellulose hydrogenolysis process steps in this example were implemented synchronously with Example 8, except that the reaction atmosphere was replaced by 3.0MPa of H2 / CO / CO2(2.0 / 0.5 / 0.5MPa). Cellulose (0.5g), 5.0wt% Pd / C catalyst (0.2g), deionized water (20.0mL) were heated to 230.0℃ in the reaction kettle for 2.0h.

[0111] The test results showed that under this reaction condition, the cellulose conversion rate was 78.5%, the yield and selectivity of product ketones were 18.5% and 23.6% respectively, other products were mainly alcohol and acid products, the yield and selectivity of alcohol products were 24.5% and 31.2% respectively, the yield and selectivity of acid products were 11.8% and 15.0% respectively, the total yield and selectivity of ketone, alcohol and acid products were 52.8% and 67.3% respectively, the test results are shown in Table 2.

[0112] Example 10: Method of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(1.5 / 1.0 / 0.5MPa) atmosphere:

[0113] The Pd / C catalyzing cellulose hydrogenolysis process steps in this example were implemented synchronously with Example 8, except that the reaction atmosphere was replaced by 3.0MPa of H2 / CO / CO2=1.5 / 1.0 / 0.5MPa. Cellulose (0.5g), 5.0wt% Pd / C catalyst (0.2g), deionized water (20.0mL) were heated to 230.0℃ in the reaction kettle for 2.0h.

[0114] The test results show that under the reaction condition, the conversion of cellulose is 89.1%, the yield and selectivity of the main product ketone compound are 37.2% and 41.8% respectively, the main other products are alcohol and acid, the yield and selectivity of alcohol compound are 22.1% and 24.8% respectively, the yield and selectivity of acid compound are 8.5% and 9.5% respectively, and the total yield and selectivity of ketone, alcohol and acid are 67.8% and 76.1% respectively. The test results are shown in Table 2.

[0115] Example 11: Method of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(1.5 / 0.5 / 1.0 MPa) atmosphere:

[0116] In this example, the process steps of catalyzing cellulose hydrogenolysis by Pd / C are the same as those in Example 8, except that the reaction atmosphere is replaced by H2 / CO / CO2(1.5 / 0.5 / 1.0 MPa) at 3.0 MPa. Cellulose (0.5 g), 5.0wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) are heated to 230.0°C in the reaction kettle for 2.0 h.

[0117] The test results show that under the reaction condition, the conversion of cellulose is 90.6%, the yield and selectivity of the main product ketone compound are 33.0% and 36.4% respectively, the main other products are alcohol and acid, the yield and selectivity of alcohol compound are 25.2% and 27.8% respectively, the yield and selectivity of acid compound are 10.7% and 11.8% respectively, and the total yield and selectivity of ketone, alcohol and acid are 68.9% and 76.0% respectively. The test results are shown in Table 2.

[0118] Example 12: Method of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(1.0 / 1.5 / 0.5 MPa) atmosphere:

[0119] In this example, the process steps of catalyzing cellulose hydrogenolysis by Pd / C are the same as those in Example 8, except that the reaction atmosphere is replaced by H2 / CO / CO2(1.0 / 1.5 / 0.5 MPa) at 3.0 MPa. Cellulose (0.5 g), 5.0wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) are heated to 230.0°C in the reaction kettle for 2.0 h.

[0120] The test results show that under the reaction condition, the conversion of cellulose is 82.5%, the yield and selectivity of the main product ketone compound are 36.2% and 49.5% respectively, the main other products are alcohol and acid, the yield and selectivity of alcohol compound are 19.3% and 23.4% respectively, the yield and selectivity of acid compound are 8.1% and 9.8% respectively, the total yield and selectivity of ketone, alcohol and acid products are 63.6% and 77.1% respectively, and the test results are shown in Table 2.

[0121] Example 13: Method of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(1.0 / 1.0 / 1.0 MPa) atmosphere:

[0122] In this example, the process steps of catalyzing cellulose hydrogenolysis by Pd / C are the same as those in Example 8, except that the reaction atmosphere is replaced by 3.0 MPa of H2 / CO / CO2(1.0 / 1.0 / 1.0 MPa). Cellulose (0.5 g), 5.0wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) are heated to 230.0°C in a reaction kettle for 2.0 h.

[0123] The test results show that under the reaction condition, the conversion of cellulose is 77.6%, the yield and selectivity of the main product ketone compound are 31.1% and 40.1% respectively, the main other products are alcohol and acid, the yield and selectivity of alcohol compound are 21.5% and 27.7% respectively, the yield and selectivity of acid compound are 7.4% and 9.5% respectively, the total yield and selectivity of ketone, alcohol and acid products are 60.0% and 77.3% respectively, and the test results are shown in Table 2.

[0124] Example 14: Method of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(1.0 / 0.5 / 1.5 MPa) atmosphere:

[0125] In this example, the process steps of catalyzing cellulose hydrogenolysis by Pd / C are the same as those in Example 8, except that the reaction atmosphere is replaced by 3.0 MPa of H2 / CO / CO2(1.0 / 0.5 / 1.5 MPa). Cellulose (0.5 g), 5.0wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) are heated to 230.0°C in a reaction kettle for 2.0 h.

[0126] The test results show that under the reaction condition, the conversion rate of cellulose is 83.5%, the yield and selectivity of the main product ketone compound are 28.1% and 33.7% respectively, the main other products are alcohol and acid, the yield and selectivity of alcohol compound are 27.2% and 32.6% respectively, the yield and selectivity of acid compound are 5.2% and 6.2% respectively, and the total yield and selectivity of ketone, alcohol and acid products are 60.5% and 72.5% respectively. The test results are shown in Table 2.

[0127] Example 15: Method of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(0.5 / 2.0 / 0.5 MPa) atmosphere:

[0128] In this example, the process steps of catalyzing cellulose hydrogenolysis by Pd / C are the same as those in Example 8, except that the reaction atmosphere is replaced by 3.0 MPa of H2 / CO / CO2(0.5 / 2.0 / 0.5 MPa). Cellulose (0.5 g), 5.0wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) are heated to 230.0°C in the reaction kettle for 2.0 h.

[0129] The test results show that under the reaction condition, the conversion rate of cellulose is 79.7%, the yield and selectivity of the main product ketone compound are 25.3% and 31.7% respectively, the main other products are alcohol and acid, the yield and selectivity of alcohol compound are 13.2% and 16.6% respectively, the yield and selectivity of acid compound are 4.9% and 6.1% respectively, and the total yield and selectivity of ketone, alcohol and acid products are 43.4% and 54.5% respectively. The test results are shown in Table 2.

[0130] Example 16: Method of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(0.5 / 1.5 / 1.0 MPa) atmosphere:

[0131] In this example, the process steps of catalyzing cellulose hydrogenolysis by Pd / C are the same as those in Example 8, except that the reaction atmosphere is replaced by 3.0 MPa of H2 / CO / CO2(0.5 / 1.5 / 1.0 MPa). Cellulose (0.5 g), 5.0wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) are heated to 230.0°C in the reaction kettle for 2.0 h.

[0132] The cellulose conversion rate under the reaction condition was 76.1%, the yield and selectivity of the main product ketone compound were 24.5% and 32.2% respectively, other products were mainly alcohol and acid products, the yield and selectivity of alcohol compound were 14.8% and 19.4% respectively, the yield and selectivity of acid compound were 4.6% and 6.0% respectively, the total yield and selectivity of 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 of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(0.5 / 0.5 / 2.0 MPa) atmosphere:

[0134] In this embodiment, the Pd / C catalyzed cellulose hydrogenolysis process steps were implemented synchronously with Example 8, except that the reaction atmosphere was replaced by 3.0 MPa of H2 / CO / CO2(0.5 / 0.5 / 2.0 MPa). Cellulose (0.5 g), 5.0wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) were heated to 230.0°C in the reaction kettle for 2.0 h.

[0135] The cellulose conversion rate under the reaction condition was 80.3%, the yield and selectivity of the main product ketone compound were 21.9% and 27.3% respectively, other products were mainly alcohol and acid products, the yield and selectivity of alcohol compound were 16.7% and 20.8% respectively, the yield and selectivity of acid compound were 3.4% and 4.2% respectively, the total yield and selectivity 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 of catalyzing cellulose by 1.0wt% Pd / C under H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa) atmosphere:

[0137] In this embodiment, the Pd / C catalyzed cellulose hydrogenolysis process steps were implemented synchronously with Example 8, except that the reaction atmosphere was replaced by 3.0 MPa of H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa) and the catalyst was replaced by 1.0wt% Pd / C (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0°C in the reaction kettle for 2.0 h.

[0138] The cellulose conversion rate under the reaction condition was 75.9%, the yield and selectivity of the main product ketone compound were 10.6% and 14.0% respectively, other products were mainly alcohol and acid products, the yield and selectivity of alcohol compound were 21.8% and 28.7% respectively, the yield and selectivity of acid compound were 9.0% and 11.9% respectively, the total yield and selectivity of ketone, alcohol and acid products were 41.4% and 54.5% respectively, and the test results are shown in Table 2.

[0139] Example 19: Method of catalyzing cellulose by 10.0wt% Pd / C under H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa) atmosphere:

[0140] In this embodiment, the Pd / C catalyzed cellulose hydrogenolysis process steps were implemented synchronously with Example 8, except that the reaction atmosphere was replaced by 3.0 MPa of H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa), and the catalyst was replaced by 10.0wt% Pd / C (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0 °C in the reaction kettle for 2.0 h.

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

[0142] Example 20: Method of catalyzing cellulose by 15.0wt% Pd / C under H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa) atmosphere:

[0143] In this embodiment, the Pd / C catalyzed cellulose hydrogenolysis process steps were implemented synchronously with Example 8, except that the reaction atmosphere was replaced by 3.0 MPa of H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa), and the catalyst was replaced by 15.0wt% Pd / C (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0 °C in the reaction kettle for 2.0 h.

[0144] The test results show that under the reaction conditions, the conversion rate of cellulose is 92.3%, the yield and selectivity of the main product ketone compound are 30.8% and 33.4% respectively, the yield and selectivity of alcohol compound are 22.3% and 24.2% respectively, the yield and selectivity of acid compound are 7.1% and 7.7% respectively, and the total yield and selectivity of ketone, alcohol and acid compounds are 60.2% and 65.2% respectively. The test results are shown in Table 2.

[0145] Example 21: Method for catalyzing cellulose by 20.0wt% Pd / C under H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa) atmosphere:

[0146] In this example, the Pd / C catalyzes the hydrogenolysis depolymerization process of cellulose, and the steps are the same as those in Example 8, except that the reaction atmosphere is replaced by 3.0 MPa of H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa), and the catalyst is replaced by 20.0wt% Pd / C (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) are heated to 230.0℃ in the reaction kettle for 2.0 h.

[0147] The test results show that under the reaction conditions, the conversion rate of cellulose is 91.7%, the yield and selectivity of the main product ketone compound are 15.3% and 16.7% respectively, the yield and selectivity of alcohol compound are 34.5% and 37.6% respectively, the yield and selectivity of acid compound are 9.6% and 10.5% respectively, and the total yield and selectivity of ketone, alcohol and acid compounds are 59.4% and 64.8% respectively. The test results are shown in Table 2.

[0148] Example 22: Method for catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(0.7 / 1.2 / 2.1 MPa) atmosphere:

[0149] In this example, the Pd / C catalyzes the hydrogenolysis depolymerization process of cellulose, and the steps are the same as those in Example 8, except that the reaction atmosphere is replaced by 4.0 MPa of H2 / CO / CO2(0.7 / 1.2 / 2.1 MPa). Cellulose (0.5 g), 5.0wt% Pd / C catalyst (0.2 g), deionized water (20.0 mL) are heated to 230.0℃ in the reaction kettle for 2.0 h.

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

[0151] Example 23: Method of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa) atmosphere:

[0152] In this embodiment, the Pd / C catalyzed cellulose hydrogenolysis process steps were implemented synchronously with Example 8, except that the reaction atmosphere was replaced by 3.0 MPa of H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa). Cellulose (0.5 g), 5.0wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) were heated to 210.0°C in the reaction kettle for 2.0 h.

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

[0154] Example 24: Method of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa) atmosphere:

[0155] In this embodiment, the Pd / C catalyzed cellulose hydrogenolysis process steps were implemented synchronously with Example 8, except that the reaction atmosphere was replaced by 3.0 MPa of H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa). Cellulose (0.5 g), 5.0wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) were heated to 260.0°C in the reaction kettle for 2.0 h.

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

[0157] Example 25: Method of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa) atmosphere:

[0158] In this embodiment, the Pd / C catalyzed cellulose hydrogenolysis process steps were implemented synchronously with Example 8, except that the reaction atmosphere was replaced by 3.0 MPa of H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa). Cellulose (0.5 g), 5.0wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) were heated to 230.0°C in the reaction kettle for 1.0 h.

[0159] The cellulose conversion rate under the reaction condition was 72.5%, the yield and selectivity of the main product ketone compound were 21.1% and 29.1% respectively, other products were mainly alcohol and acid products, the yield and selectivity of alcohol compound were 14.2% and 20.4% respectively, the yield and selectivity of acid compound were 4.1% and 5.9% respectively, the total yield and selectivity of 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 of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa) atmosphere:

[0161] In this embodiment, the Pd / C catalyzed cellulose hydrogenolysis process steps were implemented synchronously with Example 8, except that the reaction atmosphere was replaced by 3.0 MPa of H2 / CO / CO2(0.5 / 1.0 / 1.5 MPa). Cellulose (0.5 g), 5.0wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) were heated to 230.0°C in the reaction kettle for 6.0 h.

[0162] The cellulose conversion rate under the reaction condition was 92.9%, the yield and selectivity of the main product ketone compound were 32.1% and 34.6% respectively, the other products were mainly alcohol and acid products, the yield and selectivity of alcohol compound were 19.5% and 21.0% respectively, the yield and selectivity of acid compound were 7.5% and 8.1% respectively, the total yield and selectivity of 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 of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO / CO2(0.2 / 0.4 / 0.4 MPa) atmosphere:

[0164] In this example, the Pd / C catalyzes the cellulose hydrogenolysis process step synchronously with Example 8, except that the reaction atmosphere is replaced by 1.0 MPa of H2 / CO / CO2(0.2 / 0.4 / 0.4 MPa). Cellulose (0.5 g), 5.0wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) are heated to 230.0°C in the reaction kettle for 2.0 h.

[0165] The cellulose conversion rate under the reaction condition was 70.2%, the yield and selectivity of the main product ketone compound were 22.1% and 33.7% respectively, the other products were mainly alcohol and acid products, the yield and selectivity of alcohol compound were 9.4% and 13.5% respectively, the yield and selectivity of acid compound were 2.1% and 3.0% respectively, the total yield and selectivity of ketone, alcohol and acid products were 33.7% and 48.0% respectively, and the test results are shown in Table 2.

[0166] Comparative Example 1

[0167] The reaction atmosphere in this comparative example uses H2 / CO(2.9 / 0.1 MPa).

[0168] This comparative example uses the method of catalyzing cellulose by 5.0wt% Pd / C under H2 / CO(2.9 / 0.1 MPa) atmosphere:

[0169] In this comparative example, the Pd / C catalyzes the cellulose hydrogenolysis process step synchronously with Example 8, except that the reaction atmosphere is replaced by 3.0 MPa of H2 / CO=2.9 / 0.1 MPa. Cellulose (0.5 g), 5.0wt% Pd / C catalyst (0.2 g), and deionized water (20.0 mL) are heated to 230.0°C in the reaction kettle for 2.0 h.

[0170] The cellulose conversion rate under the reaction condition was 76.6%, the yield and selectivity of the product ketone compound were 8.9% and 11.6% respectively, and other products were mainly alcohol and acid products, the yield and selectivity of alcohol compound were 35.1% and 45.8% respectively, the yield and selectivity of acid compound were 8.6% and 11.2% respectively, and the total yield and selectivity of ketone, alcohol and acid products were 52.6% and 68.7% respectively, and the reaction results were listed in Table 2.

[0171] Comparative Example 2

[0172] The reaction atmosphere in the comparative example used H2 / CO2(2.9 / 0.1 MPa).

[0173] The comparative example used 5.0 wt% Pd / C to catalyze cellulose under the H2 / CO2(2.9 / 0.1 MPa) atmosphere:

[0174] The Pd / C catalyzed cellulose hydrogenolysis process in the comparative example was carried out synchronously with Example 8, except that the reaction atmosphere was replaced by H2 / CO2=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.

[0175] The cellulose conversion rate under the reaction condition was 74.2%, the yield and selectivity of the product ketone compound were 4.1% and 5.5% respectively, and other products were mainly alcohol and acid products, the yield and selectivity of alcohol compound were 37.2% and 50.1% respectively, the yield and selectivity of acid compound were 8.1% and 10.9% respectively, and the total yield and selectivity of ketone, alcohol and acid products were 49.4% and 66.6% respectively, and the reaction results were listed in Table 2.

[0176] Comparative Example 3

[0177] The reaction atmosphere in the comparative example used H2 / CO2(1.5 / 1.5 MPa).

[0178] The comparative example used 5.0 wt% Pd / C to catalyze cellulose under the H2 / CO2(1.5 / 1.5 MPa) atmosphere:

[0179] The Pd / C catalyzed cellulose hydrogenolysis process in the example was carried out synchronously with Example 8, except that the reaction atmosphere was replaced by H2 / CO2=1.5 / 1.5 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.

[0180] The test results show that under the reaction conditions, the cellulose conversion rate is 76.8%, the yield and selectivity of the main product ketone compound are 5.8% and 7.6% respectively, the main other products are alcohol and acid compounds, the yield and selectivity of the alcohol compound are 26.3% and 34.2% respectively, the yield and selectivity of the acid compound are 9.2% and 12.0% respectively, and the total yield and selectivity of the ketone, alcohol and acid compounds are 41.3% and 53.8% respectively. The test results are shown in Table 2.

[0181] Comparative Example 4

[0182] In the reaction atmosphere of the present comparative example, mixed gas is not used, and only high-purity hydrogen is used.

[0183] In the present comparative example, the method of catalyzing cellulose in a pure H2 atmosphere using 5.0wt% Pd / C is as follows:

[0184] In the present comparative example, the process steps of catalyzing cellulose hydrogenolysis using Pd / C are the same as those in Example 8, except that the reaction atmosphere is replaced by pure H2 at 3.0 MPa. Cellulose (0.5 g), 5.0wt% 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.

[0185] The test results show that under the reaction conditions, the cellulose conversion rate is 75.9%, the yield and selectivity of the main product ketone compound are 5.6% and 7.4% respectively, the main other products are alcohol and acid compounds, the yield and selectivity of the alcohol compound are 41.8% and 55.1% respectively, the yield and selectivity of the acid compound are 9.0% and 11.9% respectively, and the total yield and selectivity of the ketone, alcohol and acid compounds are 56.4% and 74.3% respectively. The test results are shown in Table 2.

[0186] Comparative Example 5

[0187] In the reaction atmosphere of the present comparative example, mixed gas is not used, and only high-purity CO is used.

[0188] In the present comparative example, the method of catalyzing cellulose in a pure H2 atmosphere using 5.0wt% Pd / C is as follows:

[0189] In the present comparative example, the process steps of catalyzing cellulose hydrogenolysis using Pd / C are the same as those in Example 8, except that the reaction atmosphere is replaced by pure H2 at 3.0 MPa. Cellulose (0.5 g), 5.0wt% 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.

[0190] The cellulose conversion rate under the reaction condition was 48.9%, the yield and selectivity of the product ketone compound were 4.6% and 9.4% respectively, and other products were mainly alcohol and acid products, the yield and selectivity of the alcohol compound were 9.2% and 18.8% respectively, the yield and selectivity of the acid compound were 5.4% and 11.0% respectively, and the total yield and selectivity of the ketone, alcohol and acid products were 19.2% and 39.3% respectively, and the test results are shown in Table 2.

[0191] Comparative Example 6

[0192] The reaction atmosphere in the present comparative example was not mixed gas, but only high-purity H2.

[0193] The present comparative example used 1.0wt% Pd / C to catalyze the cellulose under a pure H2 atmosphere:

[0194] The Pd / C catalyzed cellulose hydrogenolysis process in the present comparative example was carried out synchronously with Example 8, except that the reaction atmosphere was replaced by pure H2 at 3.0 MPa, and the catalyst was replaced by 1.0wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g) and deionized water (20.0 mL) were heated to 230.0°C in the reaction kettle for 2.0 h.

[0195] The cellulose conversion rate under the reaction condition was 32.3%, no ketone compound was detected, the yield and selectivity of the alcohol compound were 14.4% and 44.6% respectively, the yield and selectivity of the acid compound were 1.7% and 5.3% respectively, and the total yield and selectivity of the ketone, alcohol and acid products were 16.1% and 49.8% respectively, and the test results are shown in Table 2.

[0196] Comparative Example 7

[0197] The reaction atmosphere in the present comparative example was not mixed gas, but only high-purity CO.

[0198] The present comparative example used 1.0wt% Pd / C to catalyze the cellulose under a pure CO atmosphere:

[0199] The Pd / C catalyzed cellulose hydrogenolysis process in the present comparative example was carried out synchronously with Example 8, except that the reaction atmosphere was replaced by pure CO at 3.0 MPa, and the catalyst was replaced by 1.0wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g) and deionized water (20.0 mL) were heated to 230.0°C in the reaction kettle for 2.0 h.

[0200] The cellulose conversion rate under the reaction condition was 22.6%, the yield and selectivity of the product ketone compound were 0.9% and 4.0% respectively, other products were mainly alcohol and acid products, the yield and selectivity of the alcohol compound were 3.1% and 13.7% respectively, the yield and selectivity of the acid compound were 0.7% and 3.1% respectively, the total yield and selectivity of the ketone, alcohol and acid products were 4.7% and 20.8% respectively, and the test results are shown in Table 2.

[0201] Comparative Example 8

[0202] The reaction atmosphere in the present comparative example was not mixed gas, but only high-purity H2.

[0203] The present comparative example used 30.0wt% Pd / C to catalyze the cellulose under a pure H2 atmosphere:

[0204] The Pd / C catalyzed cellulose hydrogenolysis process in the present comparative example was carried out synchronously with Example 8, except that the reaction atmosphere was replaced by pure H2 at 3.0 MPa, and the catalyst was replaced by 30.0wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0°C in the reaction kettle for 2.0 h.

[0205] The cellulose conversion rate under the reaction condition was 84.5%, the yield and selectivity of the product ketone compound were 1.1% and 1.3% respectively, other products were mainly alcohol and acid products, the yield and selectivity of the alcohol compound were 53.1% and 62.8% respectively, the yield and selectivity of the acid compound were 5.7% and 6.7% respectively, the total yield and selectivity of the ketone, alcohol and acid products were 59.9% and 70.9% respectively, and the test results are shown in Table 2.

[0206] Comparative Example 9

[0207] The reaction atmosphere in the present comparative example was not mixed gas, but only high-purity CO.

[0208] The present comparative example used 30.0wt% Pd / C to catalyze the cellulose under a pure CO atmosphere:

[0209] The Pd / C catalyzed cellulose hydrogenolysis process in the present comparative example was carried out synchronously with Example 8, except that the reaction atmosphere was replaced by pure CO at 3.0 MPa, and the catalyst was replaced by 30.0wt% Pd / C catalyst (0.2 g). Cellulose (0.5 g), deionized water (20.0 mL) were heated to 230.0°C in the reaction kettle for 2.0 h.

[0210] The cellulose conversion rate under the reaction condition was 76.5%, the yield and selectivity of the product ketone compound were 7.2% and 9.4% respectively, and the main other products were alcohol and acid products, the yield and selectivity of the alcohol compound were 16.1% and 21.0% respectively, the yield and selectivity of the acid compound were 3.1% and 4.1% respectively, the total yield and selectivity of the ketone, alcohol and acid products were 26.4% and 34.5% respectively, and the test results are shown in Table 2.

[0211] Table 2

[0212]

[0213]

[0214] As can be seen from Table 2, under the condition that the Pd loading amount of the application is 1-20wt%, the hydrogen source gas containing CO and CO2 mainly consists of H2, CO and CO2, and the volume percentage content of CO and CO2 is 20%-67%, the cellulose conversion rate and the yield of ketone compound of the examples are obviously higher than those of pure H2 and pure CO. Under different reaction atmospheres (the initial partial pressures of H2, CO and CO2 are 0-3.0 MPa respectively, and the total pressure is maintained at 3.0 MPa), it can be seen from Comparative Examples 1-2 and Examples 8-20 that under the pure H2 atmosphere, the conversion rate of cellulose is 75.9%, the yield of the non-main product alcohol is the highest 41.8%, and the yield of the ketone compound is only 5.6%. When the partial pressure of CO and CO2 is increased, the yield of the alcohol compound begins to decrease, and the yield of the ketone compound begins to increase. When H2 / CO / CO2 is 0.5 / 1.0 / 1.5 MPa, the yield of the ketone compound is 38.7%, which may be due to the fact that CO inhibits the excessive hydrogenation of C=O in the ketone compound to alcohol and the increased hydrolysis rate of CO2. When the partial pressure of CO or CO2 is continuously increased, the yields of the ketone compound and the alcohol compound begin to decrease, which may be due to the fact that H2 is insufficient, and too much CO is adsorbed on Pd, resulting in insufficient catalytic active sites and reduced hydrogenolysis / hydrogenation ability. When the reaction atmosphere is pure CO, the reaction effect is the worst. As can be seen by comparing the above examples and comparative examples, H2 plays an important role in the reaction, but CO, CO2 and H2 will play a synergistic effect to promote the conversion of cellulose and the generation of ketone compounds. The appropriate mixture of H2, CO and CO2 is helpful to improve the catalytic effect.

[0215] It should be noted that normal hydrogen source gases contain varying amounts of CO and CO2, as shown in Table 2. Most H2 is produced through a water-gas conversion reaction, and removing CO and CO2 is not easy, let alone completely eliminating them. This invention utilizes a supported Pd / C catalyst to perform catalytic hydrogenolysis in a non-pure hydrogen atmosphere containing CO and CO2. Furthermore, the hydrogen source gas in this invention exhibits a wide range of CO and CO2 content; the volume percentage of CO and CO2 in the reaction atmosphere ranges from 20% to 67%, achieving cellulose hydrogenolysis to ketone compounds. This effectively reduces reaction costs and yields higher cellulose conversion rates and ketone compound selectivity. This invention provides a feasible route for the efficient conversion of cellulose.

[0216] The present invention is not limited to the embodiments described herein. Any changes, modifications, combinations, simplifications, or equivalent substitutions made that violate the spirit and principle of the present invention are included within the protection scope of the present invention.

Claims

1. A method for the production of ketone compounds by catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere, characterized by: The cellulose is used as raw material, water is used as solvent, activated carbon supported Pd is used as catalyst, and the total pressure of hydrogen source gas containing carbon monoxide and carbon dioxide is 0.5-4.0 MPa, the temperature is 230-260 o C for 1-6 h to obtain ketone compounds as main products; the volume percentage content of carbon monoxide and carbon dioxide in the hydrogen source gas containing carbon monoxide and carbon dioxide is 20%-67%; the Pd loading in the catalyst is 3-10 wt %.

2. The process for the production of ketone compounds by catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere according to claim 1, characterized in that: The mass ratio of the cellulose to the catalyst is 1:0.2-1:0.6, and the mass ratio of the cellulose to water is 1:10-1:

20.

3. The process for the production of ketone compounds by catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere according to claim 1, characterized in that: 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%.

4. The process for the production of ketone compounds by catalytic hydrogenation of cellulose based on a 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 and water, and stirring to form solution A; 2) adding water, a base, and carbon black powder to solution A under stirring to form liquid B; 3) ultrasonic treatment of liquid B, addition of reducing agent under inert atmosphere and stirring, heating to 20-90 o C reaction 0.5-6 h; the reaction product is filtered, washed, and dried under vacuum to obtain Pd / C catalyst; the reducing agent is at least one of NaBH4, vitamin C, and formaldehyde.

5. The process for the production of ketone compounds by catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere according to claim 4, characterized in that: In step 1, the Pd source precursor is at least one selected from PdCl2, Na2PdCl4and K2PdCl4; the solvent is HCl or ultrapure water; the molar volume concentration of the Pd source precursor in the solution A is 1x10 -4 ~1x10 -1 -4 mol / L; and the molar ratio of the Pd source precursor to ammonia is 1:10-50.

6. The process for the production of ketone compounds by catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere according to claim 4, 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; 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.

7. The process for the production of ketone compounds by catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere according to claim 4, characterized by: In Step 3, the power of the ultrasonic treatment is 50-150 W, the time of the ultrasonic treatment is 20-120 min; the time of the magnetic stirring is 5-240 min; the molar ratio of Pd to the reducing agent is 1:1-1000; the heating temperature is 20-90 o C. The heating rate is 2-7 o C / min.

8. The process for the production of ketone compounds by catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere according to claim 1, characterized by: The cellulose is microcrystalline cellulose and / or natural cellulose.

9. The process for the production of ketone compounds by catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere according to claim 1, characterized in that: The ketone compound-based product includes ketone compounds, alcohol compounds, and acid compounds.

10. The process for the production of ketone compounds by catalytic hydrogenation of cellulose based on a crude hydrogen atmosphere according to claim 9, characterized in that: 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; and the acid compounds are one or more of acetic acid, levulinic acid, and hexanoic acid.

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