A method for the highly selective hydrogenation of furfural to prepare cyclopentanone

Abstract

This invention provides a method for the highly selective hydrogenation of furfural to prepare cyclopentanone. Using furfural, a biomass derivative, as the raw material, cyclopentanone is obtained in one step via hydrogenation rearrangement reaction in a high-pressure reactor under a low-hydrogen pressure atmosphere and in the presence of a metal-supported catalyst, with water as the solvent. The metal-supported catalyst of this invention is prepared by co-impregnation of active metal palladium and transition metal Ni. The obtained catalyst has advantages such as high metal dispersion, strong heat and mass transfer capabilities, convenient recovery and separation, high efficiency, and good stability, which is of great significance for the economical production of chemicals. After reaction at 1 MPa H2, 180 °C, and 3 h, the furfural conversion rate and cyclopentanone selectivity reached 95% and 92.24%, respectively, with a yield of 87.63%. The reaction process conditions are mild, the raw materials are inexpensive and readily available, and quantitative conversion from furfural to cyclopentanone can be achieved in the aqueous phase, making it an environmentally friendly green chemical process.

Description

Technical Field

[0001] This invention belongs to the field of catalytic synthesis technology, specifically relating to a method for preparing cyclopentanone from the bio-based raw material furfural via aqueous phase hydrogenation, and also relating to a catalyst for cyclopentanone synthesis and its preparation method. This catalyst can efficiently catalyze the selective hydrogenation of furfural to prepare cyclopentanone. Background Technology

[0002] The rapid depletion of fossil resources and the continuous increase in greenhouse gas emissions have brought enormous challenges to humanity, including an energy crisis and environmental pollution. To address these issues, people are developing and utilizing renewable energy sources as chemical raw materials for sustainable development. Biomass is a renewable resource, and biomass-derived platform compounds can be converted into many valuable chemicals. Furfural is an important biomass platform compound, which, through hydrogenation using suitable catalysts, can be used to produce various derivatives and downstream products, such as cyclopentanone, cyclopentanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, 2-methylfuran, furan, and pentanediol. Among these compounds, cyclopentanone is an important fine chemical intermediate and a crucial raw material for the fragrance and pharmaceutical industries. Cyclopentanone can be used to prepare various anti-inflammatory and anticancer drugs such as jasmone, vanillin, and 2-n-hexylcyclopentanone, and can also be used in the synthesis of pesticides, herbicides, and rubber. Furthermore, due to its excellent solubility in various resins, cyclopentanone is widely used as a solvent in the electronics industry.

[0003] Currently, the main industrial production method for cyclopentanone is the adipic acid pyrolysis method (e.g., Chinese patent CN 1594259, European patent EP 306873). However, this route relies on the production of oxalic acid as a raw material, involves numerous steps, and includes a decarboxylation process, resulting in a relatively low theoretical yield and poor atom economy. Another technical route for cyclopentene production is the cyclopentene oxidation method (e.g., patents JP04312549, WO 349.73078372, WO349.76032532). This method typically uses a Wacker-type oxidation catalyst or N₂O as the oxidant to directly react with cyclopentene to produce cyclopentanone. Although the reaction yield is good (70-75%), this system primarily uses palladium chloride and copper chloride as active ingredients, leading to the formation of chlorine-containing byproducts during the reaction. These byproducts not only significantly corrode the reaction equipment but also contribute to the formation of these byproducts. Furthermore, oxidation methods using N₂O as an oxidant are generally carried out at high temperatures (280 °C) and high pressures (30 MPa), with harsh reaction conditions. Therefore, developing new raw materials and routes for the preparation of cyclopentanone, especially utilizing inexpensive and abundant biomass resources, is of great significance.

[0004] Furfural is a biomass-derived material, industrially produced on a large scale using inexpensive agricultural and forestry waste (such as corn cobs, sugarcane bagasse, and cottonseed hulls) as raw materials. Both furfural and cyclopentanone have five carbon atoms; therefore, the direct conversion of furfural to cyclopentanone has significant application value. In recent years, the hydrogenation rearrangement of furfural to produce cyclopentanone has gradually become a hot topic in biomass research. For example, Guoming Gao et al. introduced phosphorus into Ni / Al2O3 (Catal. Sci. Technol., 2021, 11:575–593), achieving the conversion of furfural to cyclopentanone by altering the distribution of acidic sites and adjusting the hydrogenation activity of metal sites. However, this catalyst preparation method is complex, and the phosphorus introduced during catalyst preparation generates waste liquid, making it unsuitable for large-scale production. Chinese patent CN110041168 describes the synthesis of cyclopentanone via the over-impregnation method using a 10% Co-10% Ni / TiO2 bimetallic catalyst catalyzing the aqueous hydrogenation rearrangement of furfural. The reaction, conducted at 6 MPa H2 and 140 °C for 4 h, achieved 100% furfural conversion and 51% cyclopentanone selectivity. However, the high reaction pressure and low cyclopentanone selectivity limit its large-scale production.

[0005] Therefore, developing a green and efficient heterogeneous catalyst for a highly selective catalytic process of furfural to cyclopentanone under aqueous phase and low pressure conditions has great potential for industrial application. Summary of the Invention

[0006] This invention overcomes the shortcomings of the prior art and provides a method for preparing cyclopentanone from biomass resource furfural, which has mild reaction conditions, good selectivity, high product yield, and is green and environmentally friendly.

[0007] This invention also provides a high-performance supported catalyst and its preparation method to achieve the following objectives:

[0008] 1. The catalyst synthesis process equipment is simple to operate, has fewer steps, is safe to operate, and produces no pollution. It can meet the needs of large-scale production, save costs, and has high economic benefits.

[0009] 2. The prepared catalyst exhibits excellent catalytic performance;

[0010] 3. The catalyst can be used to prepare cyclopentanone by hydrogenating furfural, which can avoid the side reaction of cyclohydrogenation and the polymerization of furfural during the reaction, increase the number of times the catalyst can be reused, and maintain a high yield of cyclopentanone.

[0011] To solve the technical problem of this invention, the proposed technical solution is: a method for preparing cyclopentanone by highly selective hydrogenation of furfural as a raw material, comprising the following steps:

[0012] (1) Preparation of metal-supported catalyst 0.5Pd0.1Ni / ZnO: A 0.5Pd0.1Ni / ZnO catalyst was synthesized by a wet co-impregnation method. The main active component was palladium, and nickel was used as the co-catalytic component. The mass ratio of the two metals was Pd:Ni = 5:1, with the mass fraction of palladium being 0.5 wt%, the mass fraction of nickel being 0.1 wt%, and the mass fraction of the support ZnO being 99.4%. The preparation method was as follows: a certain mass of metal salt was dissolved in an appropriate amount of deionized water based on the catalyst loading, and the metal ions were dispersed evenly in the water by ultrasonic vibration. Subsequently, the obtained metal precursor mixed solution was uniformly added dropwise to the ZnO support, and after grinding until the impregnation was sufficient, it was placed in a drying oven at 60-90 ℃ and dried for 9-12 h. The dried catalyst was then loaded into a tube furnace and calcined and reduced by hydrogen gas at 250-450 ℃ for 2-4 hours. h, after cooling, remove the catalyst to obtain the metal-supported 0.5Pd0.1Ni / ZnO catalyst, and then store it in a drying cabinet;

[0013] (2) Preparation of cyclopentanone from furfural: The hydrogenation rearrangement reaction of furfural was carried out in a stainless steel high-pressure reactor equipped with a magnetic stirrer. The reactant furfural, solvent water and catalyst metal-supported 0.5Pd0.1Ni / ZnO were added to the reactor. The reactor was loaded, pressurized, and the reaction was carried out in conjunction with a temperature controller and a magnetic stirrer. Before the reaction, the reactor was purged with hydrogen several times to remove air from the device. The reaction solvent was water. The initial hydrogen pressure was 0.5-1.0 MPa. The reaction temperature was 160-180 ℃. The reaction time was 120-180 min.

[0014] Preferably, the reaction conditions in step (2) are: initial hydrogen pressure of 1 MPa, reaction temperature of 180 °C, and reaction time of 3 h.

[0015] Preferably, the metal-supported catalyst is a 0.5Pd0.1Ni / ZnO catalyst, which is a palladium-nickel bimetallic catalyst synthesized by a wet co-impregnation method. The main active component is palladium, and nickel is used as the co-catalytic component. The mass ratio of the two metals is Pd:Ni = 5:1, wherein the mass fraction of palladium is 0.5 wt%, the mass fraction of nickel is 0.1 wt%, and the mass fraction of ZnO support is 99.4%. The palladium precursor is palladium nitrate dihydrate, and the nickel precursor is nickel nitrate hexahydrate.

[0016] Preferably, the catalyst obtained by the co-impregnation method needs to be loaded into a tube furnace and calcined and reduced with hydrogen at 250-450 °C for 2-4 h for activation treatment.

[0017] Preferably, the hydrogenation rearrangement reaction of furfural in step (2) is carried out in a stainless steel high-pressure reactor equipped with a magnetic stirrer; typically, a magnetic stirrer is placed in a quartz liner, and 50 mg of 0.5Pd0.1Ni / ZnO catalyst, 1 mmol of furfural, and 5 mL of water are added; the reactor is filled, pressurized, and the reaction is carried out in conjunction with a temperature controller and a magnetic stirrer.

[0018] Preferably, after the reaction in step (2) is completed, the temperature is lowered, the pressure is released, the vessel is opened, filtered, and then tested.

[0019] Preferably, in step (2), after the reaction is completed, the reaction vessel is placed in ice water and cooled to room temperature, and the catalyst and reaction liquid are separated by centrifugation; the product can be identified by gas chromatography-mass spectrometry (GC-MS); at the same time, the conversion rate of furfural and the yield of cyclopentanone are calculated by gas chromatography analysis; in addition, the filtered catalyst powder can be recycled after being continuously washed with ethanol and dried.

[0020] (1) Preparation of palladium-based bimetallic supported catalyst: The active component and promoter of the catalyst is its metal precursor salt solution. Palladium nitrate dihydrate and nickel nitrate hexahydrate were selected. 5 g of palladium nitrate dihydrate Pd(NO3)2·2H2O was dissolved in 100 mL of deionized water to prepare a palladium precursor solution Pd: 7.149 mg / mL for later use; 2.4664 g of nickel nitrate hexahydrate Ni(NO3)2·6H2O was dissolved in 50 mL of deionized water to prepare a nickel precursor solution Ni: 10 mg / mL for later use.

[0021] (2) Weigh 497 mg of ZnO support and spread it evenly on a mortar. Take 349.7 μL of palladium precursor solution, shake and sonicate before taking it, then add 45.8 μL of nickel precursor solution and an appropriate amount of deionized water, sonicate for 5 min to mix it evenly, and add the mixed solution evenly to the ZnO support. Grind until the catalyst is fully impregnated, and put it in a 70 ℃ drying oven to dry for 12 h.

[0022] (3) The impregnated and dried catalyst was taken out, ground into uniform fine particles, and then loaded into a tube furnace. The catalyst bed was filled with quartz wool on the top and bottom. The temperature was increased from room temperature to 350℃ at a hydrogen flow rate of 40 mL / min and a heating rate of 5℃ / min. The catalyst was calcined and reduced at 350℃ for 4 h. After cooling to room temperature, the pipeline was purged with nitrogen and the catalyst was taken out to obtain 0.5Pd0.1Ni / ZnO catalyst.

[0023] (4) The hydrogenation rearrangement reaction of furfural was carried out in a stainless steel high-pressure reactor equipped with a magnetic stirrer. First, 50 mg of 0.5Pd0.1Ni / ZnO catalyst, 1 mmol of furfural, and 5 mL of water were added to the stainless steel high-pressure reactor with a quartz liner, and a magnetic stirrer was added. After loading the reactor, the gas in the reactor was replaced three times with hydrogen gas at 2-3 MPa to remove the air in the reactor. The temperature was raised to the specified temperature of 180 ℃ using an automatic temperature controller, and then hydrogen gas was introduced to a pressure of 1 MPa. The stirring was turned on to start the reaction. The reaction was stopped after 3 hours. The reactor was placed in ice water to cool rapidly to room temperature, and the catalyst and reaction solution were separated by centrifugation.

[0024] (5) Sampling and analysis: The product was qualitatively identified by comparing the gas chromatographic retention time of the product with that of the standard substance cyclopentanone using gas chromatography-mass spectrometry (GC-MS). The main product was identified as cyclopentanone. The product was quantitatively identified by the external standard method of gas chromatography.

[0025] This invention provides a method for converting furfural into cyclopentanone, which requires consideration of steps such as catalytic hydrogenation and rearrangement. Therefore, it necessitates the design of catalyst systems with different functions, such as catalyst supports, active components, and promoter components. The designed catalyst is a bimetallic supported catalyst. The catalyst support is one of Al₂O₃, MgO, ZnO, SiO₂, ZrO₂, and TiO₂. The active component is Pd, and the promoter is one of Cr, Ni, Fe, Co, and Cu. The promoter loading to active component percentage mass ratio is 0.0-5.0:1.

[0026] This invention provides the following technical solution: a method for preparing cyclopentanone by highly selective hydrogenation of furfural as a raw material, comprising the following steps:

[0027] (1) Preparation of metal-supported catalyst: According to the proportion, a certain mass of metal salt (calculated based on the catalyst loading) is dissolved in an appropriate amount of deionized water, and the metal ions are dispersed evenly in the water by oscillation and sonication; then, the obtained metal precursor mixed solution is uniformly added dropwise to the support, ground until fully impregnated, and then placed in a drying oven at 60-90 ℃ for 9-12 h; the dried catalyst is placed in a tube furnace and calcined and reduced by hydrogen gas at 250-450 ℃ for 2-4 h, and then taken out after cooling to obtain the supported palladium-based bimetallic catalyst, which is then stored in a drying oven;

[0028] (2) Preparation of cyclopentanone from furfural: The hydrogenation rearrangement reaction of furfural was carried out in a stainless steel high-pressure reactor equipped with a magnetic stirrer. Typically, the reactants, solvent, and catalyst were added to the reactor; the reactor was loaded, pressurized, and the reaction was carried out with the assistance of a temperature controller and a magnetic stirrer; before the reaction, the reactor was purged several times with hydrogen to remove air from the apparatus; the reaction solvent was selected from one or more of six typical representative solvents, including protic solvents: water, methanol, ethanol, isopropanol, and aprotic solvents: methyl isobutyl ketone, 1,4-dioxane; the initial hydrogen pressure was 0.1-4 MPa; the reaction temperature was 150-210 ℃; the reaction time was 30-240 min; after the reaction, the temperature was lowered, the pressure was released, the reactor was opened, filtered, and the reaction was performed.

[0029] A high-performance supported metal catalyst is obtained by co-impregnation of palladium and another transition metal onto a support. The active component of the catalyst is selected as Pd, and the transition metal is added as a promoter to the palladium-based catalyst. The transition metal is selected from Cr, Ni, Fe, Co, Cu, etc. The precursor of the transition metal is a solution of its metal salt.

[0030] The support is selected from Al2O3, MgO, ZnO, SiO2, ZrO2, and TiO2; ZnO is the preferred support.

[0031] The reaction solvent in step (2) is selected from one or more of water, methanol, ethanol, isopropanol, methyl isobutyl ketone, and 1,4-dioxane; water is preferred as the co-solvent.

[0032] The reaction conditions in step (2) are: initial hydrogen pressure of 0.1-4 MPa; reaction temperature of 100-220 ℃; reaction time of 30-240 min; and more preferably, initial hydrogen pressure of 1 MPa, reaction temperature of 180 ℃, reaction time of 3 h, and water as solvent.

[0033] The principle of this invention is as follows:

[0034]

[0035] Beneficial effects:

[0036] This invention utilizes furfural, an abundant and inexpensive biomass derivative, as a raw material to prepare cyclopentanone in a one-pot process. The process is simplified, the reaction conditions are mild, production costs are reduced, the overall yield is high, and the hydrogenation product has high added value. In the method provided by this invention, the conversion of furfural to cyclopentanone is carried out in an aqueous medium. Water is a cheap and abundant natural solvent; using water instead of organic solvents is beneficial for both reducing production costs and environmental protection. The supported metal catalyst provided by this invention has highly active hydrogenation centers and is stable in the aqueous phase. Simultaneously, the support provides weak Lewis acid centers, and the PdNi bimetallic catalyst works synergistically with the support to improve the conversion rate of furfural and its derivatives and the selectivity of cyclopentanone compounds. In particular, under low hydrogen pressure conditions of 180 °C and 1 MPa, the 0.5Pd0.1Ni / ZnO catalyst in the aqueous phase exhibits excellent activity, with a furfural conversion rate of 95%, a cyclopentanone selectivity of 92.24%, and a yield of 87.63%. Under similar conditions, this yield is superior to most currently reported catalysts.

[0037] Compared to the PtCoSiO2 supported metal catalyst used in Chinese patent CN114605246B for the preparation of cyclopentanone from furfural, the supported metal catalyst provided by this invention has significant advantages in terms of activity and economic benefits, achieving higher cyclopentanone selectivity with lower noble metal loading.

[0038] Furthermore, both furfural and cyclopentanone are C5 compounds, resulting in no carbon loss during the reaction and high atom economy. The conversion from furfural to cyclopentanone can be completed in a single step in a reactor or in a fixed-bed reactor without the need to separate intermediate products. Compared with existing production technologies, this invention offers the following significant advantages: a simple preparation process, no need for external acid or alkaline additives, renewable raw materials, a highly active and stable catalyst, milder reaction conditions, reduced energy consumption to some extent, and greater environmental friendliness, potentially alleviating the global energy crisis. Therefore, this invention has broad application potential in industrial production. Attached Figure Description

[0039] Figure 1 Evaluation of the catalytic performance of palladium-based catalysts with different supports

[0040] Figure 2 The effect of different metal additives on the reactivity

[0041] Figure 3 Effect of nickel loading on reaction activity in palladium-based bimetallic catalysts

[0042] Figure 4 Effect of palladium loading on reaction activity in palladium-based bimetallic catalysts

[0043] Figure 5 Effect of reaction temperature on product distribution

[0044] Figure 6 Effect of reaction pressure on product distribution

[0045] Figure 7 The effect of reaction solvent on product distribution

[0046] Figure 8 The effect of mixed solvents on product distribution

[0047] Figure 9 Effect of reaction time on product distribution

[0048] Figure 10 XRD patterns of several catalysts in the catalyst screening process and the best-performing 0.5%Pd0.1%Ni-ZnO catalyst.

[0049] Figure 11 Reaction pathway diagram for the preparation of cyclopentanone from furfural Detailed Implementation

[0050] The present invention will be further described in detail below with reference to specific examples. These embodiments are only for illustrating the present invention, but the present invention is not limited to the following embodiments.

[0051] Example 1

[0052] (1) Preparation of palladium-based single-metal supported catalyst: The active component of the catalyst can be a precursor salt solution of palladium metal. Here we take palladium nitrate dihydrate as an example. Take 5g of palladium nitrate dihydrate Pd(NO3)2·2H2O and dissolve it in 100mL of deionized water to prepare a palladium precursor solution (Pd: 7.149 mg / mL) for later use.

[0053] (2) Weigh 497.5 mg of ZnO support and spread it evenly on a mortar. Take 349.7 μL of palladium precursor solution, shake and sonicate before taking it, then add an appropriate amount of deionized water so that it can just wet the support, sonicate for 5 min, and then evenly drop the palladium precursor solution onto the ZnO support. Grind until the catalyst is fully impregnated, and put it into a 70 ℃ drying oven to dry for 12 h.

[0054] (3) The impregnated and dried catalyst was removed, ground into uniform fine particles, and then loaded into a tube furnace. The catalyst bed was lined with quartz wool on both sides. Under a hydrogen flow (flow rate of 40 mL / min), the temperature was increased from room temperature to 350℃ at a rate of 5℃ / min, and calcined and reduced at 350℃ for 4 h. After cooling to room temperature, the pipeline was purged with nitrogen, and the catalyst was removed to obtain 0.5wt% Pd / ZnO catalyst;

[0055] (4) The hydrogenation rearrangement reaction of furfural was carried out in a stainless steel high-pressure reactor equipped with a magnetic stirrer. First, 50 mg of 0.5wt% Pd / ZnO catalyst, 1 mmol of furfural, and 5 mL of water were added to the stainless steel high-pressure reactor with a quartz liner, and a magnetic stirrer was added. After loading, the gas inside the reactor was replaced three times with hydrogen gas at 2-3 MPa to remove air from the reactor. The temperature was raised to the specified temperature of 160 °C using an automatic temperature controller, and then hydrogen gas was introduced to a pressure of 1 MPa. The stirring was then turned on to start the reaction. The reaction was stopped after 3 hours. The reactor was then placed in ice water to cool rapidly to room temperature, and the catalyst and reaction solution were separated by centrifugation.

[0056] (5) Sampling and analysis: The product was qualitatively identified by comparing the retention times of the gas chromatography-mass spectrometry (GC-MS) and the standard substance (cyclopentanone). The main product was identified as cyclopentanone. Quantitative analysis was performed using the external standard method of gas chromatography.

[0057] Example 2

[0058] (1) Preparation of palladium-based bimetallic supported catalyst: The active component and promoter of the catalyst can be its metal precursor salt solution. Here, we take the preferred palladium nitrate dihydrate and nickel nitrate hexahydrate as examples. Take 5g of palladium nitrate dihydrate Pd(NO3)2·2H2O and dissolve it in 100mL of deionized water to prepare a palladium precursor solution (Pd: 7.149 mg / mL) for later use; take 2.4664g of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) and dissolve it in 50mL of deionized water to prepare a nickel precursor solution Ni: 10 mg / mL for later use.

[0059] (2) Weigh 497 mg of ZnO support and spread it evenly on a mortar. Take 349.7 μL of palladium precursor solution, shake and sonicate before taking it, then add 45.8 μL of nickel precursor solution and an appropriate amount of deionized water, sonicate for 5 min to mix it evenly, and add the mixed solution evenly to the ZnO support. Grind until the catalyst is fully impregnated, and put it in a 70 ℃ drying oven to dry for 12 h.

[0060] (3) The impregnated and dried catalyst was removed, ground into uniform fine particles, and then loaded into a tube furnace. Quartz wool was placed on both the top and bottom of the catalyst bed. Under a hydrogen flow (flow rate of 40 mL / min), the temperature was increased from room temperature to 350℃ at a rate of 5℃ / min, and calcined and reduced at 350℃ for 4 h. After cooling to room temperature, the pipeline was purged with nitrogen, and the catalyst was removed to obtain a 0.5Pd0.1Ni / ZnO catalyst. The mass ratio of the two metals was Pd:Ni = 5:1, with palladium and nickel each having a mass fraction of 0.6 wt%, and the ZnO support having a mass fraction of 99.4%.

[0061] (4) The hydrogenation rearrangement reaction of furfural was carried out in a stainless steel high-pressure reactor equipped with a magnetic stirrer. First, 50 mg of 0.5Pd0.1Ni / ZnO catalyst, 1 mmol of furfural, and 5 mL of water were added to a stainless steel high-pressure reactor fitted with quartz, and a magnetic stirrer was added. After loading, the gas inside the reactor was replaced three times with hydrogen gas at 2-3 MPa to remove air from the reactor. The temperature was raised to the specified temperature of 160 °C using an automatic temperature controller, and then hydrogen gas was introduced to a pressure of 1 MPa. The stirring was then turned on to start the reaction. The reaction was stopped after 3 hours. The reactor was then placed in ice water to cool rapidly to room temperature, and the catalyst and reaction solution were separated by centrifugation.

[0062] (5) Sampling and analysis: The product was qualitatively identified by comparing the retention times of the gas chromatography-mass spectrometry (GC-MS) and the standard substance (cyclopentanone). The main product was identified as cyclopentanone. Quantitative analysis was performed using the external standard method of gas chromatography.

[0063] Example 3

[0064] Investigating the effect of temperature on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 2 is that the reaction temperature in step (4) is 150 °C, while the other processes are the same as in Example 2.

[0065] Example 4

[0066] Investigating the effect of temperature on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 2 is that the reaction temperature in step (4) is 170 °C, while the other processes are the same as in Example 2.

[0067] Example 5

[0068] Investigating the effect of temperature on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 2 is that the reaction temperature in step (4) is 180 °C, while the other processes are the same as in Example 2.

[0069] Example 6

[0070] Investigating the effect of temperature on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 2 is that the reaction temperature in step (4) is 190 °C, while the other processes are the same as in Example 2.

[0071] Example 7

[0072] Investigating the effect of temperature on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 2 is that the reaction temperature in step (4) is 200 °C, while the other processes are the same as in Example 2.

[0073] Example 8

[0074] Investigating the effect of temperature on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 2 is that the reaction temperature in step (4) is 210 °C, while the other processes are the same as in Example 2.

[0075] Example 9

[0076] Investigating the effect of pressure on the hydrogenation of furfural to prepare cyclopentanone:

[0077] (1) Preparation of palladium-based bimetallic supported catalyst: The active component and promoter of the catalyst can be its metal precursor salt solution. Here, we take the preferred palladium nitrate dihydrate and nickel nitrate hexahydrate as examples. Take 5g of palladium nitrate dihydrate Pd(NO3)2·2H2O and dissolve it in 100mL of deionized water to prepare a palladium precursor solution (Pd: 7.149 mg / mL) for later use; take 2.4664g of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) and dissolve it in 50mL of deionized water to prepare a nickel precursor solution Ni: 10 mg / mL for later use.

[0078] (2) Weigh 497 mg of ZnO support and spread it evenly on a mortar. Take 349.7 μL of palladium precursor solution, shake and sonicate before taking it, then add 45.8 μL of nickel precursor solution and an appropriate amount of deionized water, sonicate for 5 min to mix it evenly, and add the mixed solution evenly to the ZnO support. Grind until the catalyst is fully impregnated, and put it in a 70 ℃ drying oven to dry for 12 h.

[0079] The impregnated and dried catalyst was removed, ground into uniform fine particles, and then loaded into a tube furnace. Quartz wool was placed on both the top and bottom of the catalyst bed. Under a hydrogen flow (40 mL / min), the temperature was increased from room temperature to 350 °C at a rate of 5 °C / min, and calcined and reduced at 350 °C for 4 h. After cooling to room temperature, the pipeline was purged with nitrogen, and the catalyst was removed to obtain a 0.5Pd0.1Ni / ZnO catalyst. Figure 10 The XRD patterns of several catalysts in the catalyst screening process and the best-performing 0.5%Pd0.1%Ni-ZnO catalyst are shown. It can be seen from the figure that the dispersion of Pd increases significantly with the decrease of noble metal Pd loading and the doping of base metal Ni.

[0080] (3) The hydrogenation rearrangement reaction of furfural was carried out in a stainless steel high-pressure reactor equipped with a magnetic stirrer. First, 50 mg of 0.5Pd0.1Ni / ZnO catalyst, 1 mmol of furfural, and 5 mL of water were added to a stainless steel high-pressure reactor fitted with quartz, and a magnetic stirrer was added. After loading, the gas inside the reactor was replaced three times with hydrogen gas at 2-3 MPa to remove the air in the reactor, and then hydrogen gas was introduced to 1 MPa. The temperature was raised to the specified temperature of 180 °C using an automatic temperature controller, and the stirring was turned on to start the reaction. The reaction was stopped after 3 hours. The reactor was then placed in ice water to cool rapidly to room temperature, and the catalyst and reaction solution were separated by centrifugation.

[0081] (4) Sampling and analysis: The product was qualitatively identified by comparing the retention times of the gas chromatography-mass spectrometry (GC-MS) and the standard substance (cyclopentanone). The main product was identified as cyclopentanone. Quantitative analysis was performed using the external standard method of gas chromatography.

[0082] Example 10

[0083] Investigating the effect of pressure on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 9 is that the reaction pressure in step (4) is 0 MPa, while the other processes are the same as in Example 9.

[0084] Example 11

[0085] Investigating the effect of pressure on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 9 is that the reaction pressure in step (4) is 0.5 MPa, while the other processes are the same as in Example 9.

[0086] Example 12

[0087] Investigating the effect of pressure on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 9 is that the reaction pressure in step (4) is 1.5 MPa, while the other processes are the same as in Example 9.

[0088] Example 13

[0089] Investigating the effect of pressure on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 9 is that the reaction pressure in step (4) is 2 MPa, while the other processes are the same as in Example 9.

[0090] Example 14

[0091] Investigating the effect of pressure on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 9 is that the reaction pressure in step (4) is 2.5 MPa, while the other processes are the same as in Example 9.

[0092] Example 15

[0093] Investigating the effect of reaction solvent on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 9 is that the reaction solvent in step (4) is methyl isobutyl ketone, while the other processes are the same as in Example 15.

[0094] Example 17

[0095] Investigating the effect of reaction solvent on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 9 is that the reaction solvent in step (4) is 1,4-dioxane, while the other processes are the same as in Example 15.

[0096] Example 18

[0097] Investigating the effect of reaction solvent on the preparation of cyclopentanone by hydrogenation of furfural: The difference between this example and Example 9 is that the reaction solvent in step (4) is methanol, while the other processes are the same as in Example 15.

[0098] Example 19

[0099] Investigating the effect of reaction solvent on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 9 is that the reaction solvent in step (4) is ethanol, while the other processes are the same as in Example 15.

[0100] Example 20

[0101] Investigating the effect of reaction solvent on the hydrogenation of furfural to prepare cyclopentanone: The difference between this example and Example 9 is that the reaction solvent in step (4) is isopropanol, while the other processes are the same as in Example 15.

[0102] Example 21

[0103] Catalyst stability test: The operating procedures in this embodiment are the same as in Example 9, but the catalyst was recovered after repeated washing with ethanol and drying following the first reaction. The yield of cyclopentanone in the second reaction was 83%.

[0104] Example 22

[0105] Catalyst stability test: The operating procedures in this embodiment are the same as in Example 9, but the catalyst was recovered after repeated washing with ethanol and drying following the second reaction. The cyclopentanone yield was 84% ​​in the third reuse.

[0106] Example 23

[0107] Catalyst stability test: The operating procedures in this embodiment are the same as in Example 9, but the catalyst was recovered after repeated washing with ethanol and drying following the third reaction. The fourth reuse yielded 81% cyclopentanone.

[0108] Example 24

[0109] Catalyst stability test: The operating procedures in this embodiment are the same as in Example 9, but the catalyst was recovered after repeated washing with ethanol and drying following the fourth reaction. The fifth reaction yielded 79% cyclopentanone.

[0110] Comparative Example 1

[0111] (1) Effect of catalyst composition: By replacing the auxiliary component Ni in Example 9 with any one of the transition metals such as Co, Fe, Cu, and Cr, and using ZnO as the support, catalysts such as 0.5Pd0.1Co / ZnO, 0.5Pd0.1Fe / ZnO, 0.5Pd0.1Cu / ZnO, and 0.5Pd0.1Cr / ZnO can be obtained. The active component and auxiliary component of the catalyst are both their metal precursor salt solutions. Here, we take the preferred palladium nitrate dihydrate and nickel nitrate hexahydrate as examples. 5g of palladium nitrate dihydrate Pd(NO3)2·2H2O was dissolved in 100mL of deionized water to prepare a palladium precursor solution (Pd: 7.149 mg / mL) for later use; 2.4774g of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) was dissolved in 50mL of deionized water to prepare a nickel precursor solution Ni: 10 mg / mL for later use.

[0112] (2) Weigh 497 mg of ZnO support and spread it evenly on a mortar. Take 349.7 μL of palladium precursor solution, shake and sonicate before taking it, then add 45.8 μL of nickel precursor solution and an appropriate amount of deionized water, sonicate for 5 min to mix it evenly, and add the mixed solution evenly to the ZnO support. Grind until the catalyst is fully impregnated, and put it in a 70 ℃ drying oven to dry for 12 h.

[0113] (3) The impregnated and dried catalyst was removed, ground into uniform fine particles, and then loaded into a tube furnace. The catalyst bed was lined with quartz wool on both sides. Under a hydrogen flow (flow rate of 40 mL / min), the temperature was increased from room temperature to 350℃ at a rate of 5℃ / min, and calcined and reduced at 350℃ for 4 h. After cooling to room temperature, the pipeline was purged with nitrogen gas, and the catalyst was removed to obtain 0.5Pd0.1Ni / ZnO catalyst;

[0114] (4) The hydrogenation rearrangement reaction of furfural was carried out in a stainless steel high-pressure reactor equipped with a magnetic stirrer. First, 50 mg of 0.5Pd0.1Ni / ZnO catalyst, 1 mmol of furfural, and 5 mL of water were added to the stainless steel high-pressure reactor with a polytetrafluoroethylene liner, and a magnetic stirrer was added. After loading, the gas inside the reactor was replaced three times with hydrogen gas at 2-3 MPa to remove air from the reactor. The temperature was raised to the specified temperature of 180 °C using an automatic temperature controller, and then hydrogen gas was introduced to a pressure of 1 MPa. The stirring was then turned on to start the reaction. The reaction was stopped after 3 hours. The reactor was then placed in ice water to cool rapidly to room temperature, and the catalyst and reaction solution were separated by centrifugation.

[0115] (5) Sampling and analysis: The product was qualitatively identified by comparing the retention times of GC-MS and the standard substance (cyclopentanone) by gas chromatography. The main product was identified as cyclopentanone. Quantitative analysis was performed using the external standard method of gas chromatography.

[0116] (6) Performance of furfural hydrogenation to cyclopentanone with different catalyst components. The performance results are shown in […]. Figure 2

[0117] Comparative Example 2

[0118] (1) Preparation of 0.1Ni / ZnO catalyst: Here we take the preferred nickel nitrate hexahydrate as an example. Take 2.4664 g of nickel nitrate hexahydrate (Ni(NO3)2 · 6H2O) and dissolve it in 50 mL of deionized water to prepare a nickel precursor solution Ni: 10 mg / mL for later use.

[0119] (2) Weigh 499.5 mg of ZnO support and spread it evenly on a mortar. Take 45.8 μL of nickel precursor solution, shake and sonicate before taking it, then add an appropriate amount of deionized water so that it can just wet the support. Sonicate for 5 min, then evenly drop the metallic nickel precursor solution onto the ZnO support, grind until the catalyst is fully impregnated, and put it into a 70 ℃ drying oven to dry for 12 h.

[0120] (3) The impregnated and dried catalyst was removed, ground into uniform fine particles, and then loaded into a tube furnace. The catalyst bed was lined with quartz wool on both sides. Under a hydrogen flow (flow rate of 40 mL / min), the temperature was increased from room temperature to 350℃ at a rate of 5℃ / min, and calcined and reduced at 350℃ for 4 h. After cooling to room temperature, the pipeline was purged with nitrogen, and the catalyst was removed to obtain 0.1wt.% Ni / ZnO catalyst;

[0121] (4) The hydrogenation rearrangement reaction of furfural was carried out in a stainless steel high-pressure reactor equipped with a magnetic stirrer. First, 50 mg of Ni / ZnO catalyst, 1 mmol of furfural, and 5 mL of water were added to the stainless steel high-pressure reactor with a quartz liner, and a magnetic stirrer was added. After loading, the gas inside the reactor was replaced three times with hydrogen gas at 2-3 MPa to remove air from the reactor. The temperature was raised to the specified temperature of 180 °C using an automatic temperature controller, and then hydrogen gas was introduced to a pressure of 1 MPa. The stirring was then turned on to start the reaction. The reaction was stopped after 3 hours. The reactor was then placed in ice water to cool rapidly to room temperature, and the catalyst and reaction solution were separated by centrifugation.

[0122] (5) Sampling and analysis: The product was qualitatively identified by comparing the retention times of GC-MS and the standard substance (cyclopentanone) by gas chromatography. The main product was identified as cyclopentanone. Quantitative analysis was performed using the external standard method of gas chromatography.

[0123] Comparative Example 3

[0124] Effect of the support: By changing the support in Example 1 to Al2O3, MgO, SiO2, TiO2, and ZrO2, catalysts such as Pd / Al2O3, Pd / MgO, Pd / SiO2, Pd / TiO2, and Pd / ZrO2 can be obtained. All other aspects remain the same as in Example 1. The performance results of furfural hydrogenation to cyclopentanone on different supports are shown in [Figure 1]. Figure 1

[0125] Comparative Example 4

[0126] Effect of Ni loading on additive metal: The percentage content of Ni in the additive component in Example 9 was changed to 0, 0.3, 0.5, 0.7, 1.0, 3.0, 5.0, and 7.0. Using ZnO as the preferred support, Pd / ZnO and PdNi can be obtained. 0.3 / ZnO,PdNi 0.5 / ZnO, PdNi 0.7 / ZnO, PdNi1 / ZnO, PdNi3 / ZnO, PdNi5 / ZnO. All others are the same as in Example 9. The reaction results of the effect of metallic Ni loading on the hydrogenation performance of furfural to prepare cyclopentanone are shown in […]. Figure 3

[0127] Comparative Example 5

[0128] Effect of reaction time on product distribution:

[0129] The difference in this comparative example is that the reaction time in step (4) of Example 9 was changed to 30 min, 60 min, 90 min, 120 min, 150 min, 180 min, 210 min, and 240 min. Everything else is the same as in Example 9. The reaction results are shown below. Figure 9 .

[0130] Comparative Example 6

[0131] Experiments were conducted to prepare cyclopentanone from furfural by hydrogenation using different ratios of ethanol and water as solvents. The total solution volume was kept constant, while the ethanol-to-water ratios were 100:0, 75:25, 50:50, 25:75, and 0:100. The reaction results are shown in [Figure number missing]. Figure 7 This demonstrates that the solvent water is crucial for the production of cyclopentanone.

[0132] according to Figure 1 We investigated the effect of Pd single-metal loading on the reactivity of the reaction. Since the support surface has abundant acid / base active sites, and the ratio of acid / base active sites has a certain influence on the reaction selectivity, we first selected several representative supports based on their acidity or basicity; such as acidic or weakly acidic oxides SiO2; basic oxides ZnO and MgO; and amphoteric oxide Al2O3. The reaction results indicate that ZnO is the most favorable support for the hydrogenation of furfural to cyclopentanone.

[0133] according to Figure 2 Experimental results show that, with ZnO as the preferred support, introducing nickel as a promoter component onto a palladium monometallic catalyst can improve the selectivity of cyclopentanone to a certain extent. Specifically, on the 0.5Pd0.1Ni / ZnO catalyst, the conversion rate of furfural was 95%, the selectivity of cyclopentanone was 92.24%, and the yield reached 87.63%.

[0134] according to Figure 3 and Figure 4 We further investigated the effect of metal loading on catalytic activity. The reaction results showed that the 0.5Pd0.1Ni / ZnO bimetallic catalyst exhibited the best catalytic activity. Further increasing the content of nickel as an additive may have led to the aggregation of metal particles on the support, which is not conducive to the hydrogenation of furfural to cyclopentanone.

[0135] according to Figure 5 This demonstrates the effect of reaction temperature on product distribution. At low temperatures (<120 °C), the reaction primarily produces furfuryl alcohol. The yield of cyclopentanone increases with increasing temperature, reaching a maximum at 180 °C. Further increases in reaction temperature result in the excessive hydrogenation of cyclopentanone to cyclopentanol.

[0136] according to Figure 6 The results demonstrate the effect of reaction pressure on product distribution. Cyclopentanone selectivity increases with increasing pressure (0–1 MPa), reaching its peak at 1 MPa. Further increasing the reaction pressure (>1 MPa) leads to excessive hydrogenation of cyclopentanone to cyclopentanol.

[0137] Figure 7 and Figure 8 This demonstrates that the choice of solvent is crucial for the liquid-phase hydrogenation reaction of furfural. In particular, water plays a vital role in the hydrogenation rearrangement of furfural to prepare cyclopentanone.

[0138] Figure 9 The effect of reaction time on product distribution was demonstrated; the yield of cyclopentanone gradually increased to a maximum as the reaction time increased from 30 min to 3 h. Further extending the reaction time to 240 min resulted in the partial hydrogenation of cyclopentanone to cyclopentanol.

[0139] Based on the reaction results and related characterization, this invention studies the palladium-nickel bimetallic catalytic reaction of furfural hydrogenation rearrangement to cyclopentanone on six common supports under mild reaction conditions. A simple and reproducible method is developed to support metal loading on ZnO. Through optimization of reaction conditions, it was found that on the optimized 0.5Pd0.1Ni / ZnO catalyst, complete conversion of furfural in the aqueous phase can be achieved at a low hydrogen pressure of 1 MPa and 180 °C. The conversion rate of furfural is 95%, the selectivity of cyclopentanone is as high as 92.24%, and the yield reaches 87.63%. In the current catalytic system, the surface synergy between the basic centers and metal species on the 0.5Pd0.1Ni / ZnO catalyst greatly promotes the rearrangement of furfural intermediates, thereby forming the target cyclopentanone product in high yield. These findings provide a high-performance metal-supported catalyst for the conversion of furfural to cyclopentanone in the aqueous phase. This readily available, efficient, and stable metal-supported heterogeneous catalyst has broad prospects for industrial application. Compared to traditional production processes, this invention features a simpler preparation process that requires no additional acid or alkaline additives, uses renewable raw materials, and operates under milder reaction conditions. This reduces energy consumption to some extent, is more environmentally friendly, and can partially alleviate the global energy problem currently facing the world.

[0140] The present invention is not limited to the specific technical solutions described in the above embodiments. All technical solutions formed by equivalent substitutions are within the scope of protection claimed by the present invention.

Claims

1. A method for preparing cyclopentanone by highly selective hydrogenation of furfural as a raw material, characterized in that: Includes the following steps: (1) Preparation of metal-supported catalyst 0.5Pd0.1Ni / ZnO: A 0.5Pd0.1Ni / ZnO catalyst was synthesized by a wet co-impregnation method. The main active component was palladium, and nickel was used as the co-catalytic component. The mass ratio of the two metals was Pd:Ni = 5:1, with the mass fraction of palladium being 0.5 wt%, the mass fraction of nickel being 0.1 wt%, and the mass fraction of the support ZnO being 99.4%. The preparation method was as follows: a certain mass of metal salt was dissolved in an appropriate amount of deionized water based on the catalyst loading, and the metal ions were dispersed evenly in the water by ultrasonic vibration. Subsequently, the obtained metal precursor mixed solution was uniformly added dropwise to the support ZnO, and after grinding until the impregnation was sufficient, it was placed in a drying oven at 60-90 ℃ and dried for 9-12 h. The dried catalyst was then placed in a tube furnace and calcined and reduced by hydrogen gas at 250-450 ℃ for 2-4 hours. h, after cooling, remove the catalyst to obtain the metal-supported 0.5Pd0.1Ni / ZnO catalyst, and then store it in a drying cabinet; (2) Preparation of cyclopentanone from furfural: The hydrogenation rearrangement reaction of furfural was carried out in a stainless steel high-pressure reactor equipped with a magnetic stirrer. The reactants furfural, solvent water and catalyst metal-supported 0.5Pd0.1Ni / ZnO were added to the reactor. The reactor was loaded, pressurized, and the reaction was carried out in conjunction with a temperature controller and a magnetic stirrer. Before the reaction, the reactor was purged with hydrogen several times to remove air from the device. The reaction solvent was water. The initial hydrogen pressure was 0.5-1.0 MPa. The reaction temperature was 160-180 ℃. The reaction time was 120-180 min.

2. The method for preparing cyclopentanone by highly selective hydrogenation of furfural as a raw material according to claim 1, characterized in that: In step (2), the reaction conditions are: initial hydrogen pressure of 1 MPa, reaction temperature of 180 °C, and reaction time of 3 h.

3. The method for preparing cyclopentanone by highly selective hydrogenation of furfural as a raw material according to claim 1, characterized in that: The metal-supported catalyst is a 0.5Pd0.1Ni / ZnO catalyst, which was synthesized by a co-impregnation method. The main active component is palladium, and nickel is used as the co-catalytic component. The mass ratio of the two metals is Pd:Ni = 5:1, wherein the mass fraction of palladium is 0.5 wt%, the mass fraction of nickel is 0.1 wt%, and the mass fraction of ZnO support is 99.4%. The palladium precursor is palladium nitrate dihydrate, and the nickel precursor is nickel nitrate hexahydrate.

4. The method for preparing cyclopentanone by highly selective hydrogenation of furfural as a raw material according to claim 1, characterized in that: The catalyst obtained by the co-impregnation method needs to be loaded into a tube furnace and calcined and reduced with hydrogen at 350 °C for 4 h for activation treatment.

5. The method for preparing cyclopentanone by highly selective hydrogenation of furfural as a raw material according to claim 1, characterized in that: The hydrogenation rearrangement reaction of furfural in step (2) is carried out in a stainless steel high-pressure reactor equipped with a magnetic stirrer. Typically, a magnetic stirrer is placed in a quartz liner, and 50 mg of 0.5Pd0.1Ni / ZnO catalyst, 1 mmol of furfural, and 5 mL of water are added. The reactor is then filled, pressurized, and the reaction is carried out in conjunction with a temperature controller and a magnetic stirrer.

6. The method for preparing cyclopentanone by highly selective hydrogenation of furfural as a raw material according to claim 1, characterized in that: After the reaction in step (2) is completed, the temperature is lowered, the pressure is released, the vessel is opened, filtered, and then tested.

7. The method for preparing cyclopentanone by highly selective hydrogenation of furfural as a raw material according to claim 1, characterized in that: In step (2), after the reaction is completed, the reaction vessel is placed in ice water and cooled to room temperature. The catalyst and reaction solution are then separated by centrifugation. The product can be identified by gas chromatography-mass spectrometry (GC-MS). At the same time, the conversion rate of furfural and the yield of cyclopentanone are calculated by gas chromatography analysis. In addition, the filtered catalyst powder can be recycled after continuous ethanol washing and drying.

8. The method for preparing cyclopentanone by highly selective hydrogenation of furfural as a raw material according to claim 1, characterized in that: (1) Preparation of palladium-based bimetallic supported catalyst: The active component and promoter of the catalyst is its metal precursor salt solution. Palladium nitrate dihydrate and nickel nitrate hexahydrate were selected. 5 g of palladium nitrate dihydrate Pd(NO3)2·2H2O was dissolved in 100 mL of deionized water to prepare a palladium precursor solution Pd: 7.149 mg / mL for later use; 2.4664 g of nickel nitrate hexahydrate Ni(NO3)2·6H2O was dissolved in 50 mL of deionized water to prepare a nickel precursor solution Ni: 10 mg / mL for later use. (2) Weigh 497 mg of ZnO support and spread it evenly on a mortar. Take 349.7 μL of palladium precursor solution, shake and sonicate before taking it, then add 45.8 μL of nickel precursor solution and an appropriate amount of deionized water, sonicate for 5 min to mix it evenly, and add the mixed solution evenly to the ZnO support. Grind until the catalyst is fully impregnated, and put it in a 70 ℃ drying oven to dry for 12 h. (3) The impregnated and dried catalyst was taken out, ground into uniform fine particles, and then loaded into a tube furnace. The catalyst bed was filled with quartz wool on the top and bottom. The temperature was increased from room temperature to 350℃ at a hydrogen flow rate of 40 mL / min and a heating rate of 5℃ / min. The catalyst was calcined and reduced at 350℃ for 4 h. After cooling to room temperature, the pipeline was purged with nitrogen and the catalyst was taken out to obtain 0.5Pd0.1Ni / ZnO catalyst. (4) The hydrogenation rearrangement reaction of furfural was carried out in a stainless steel high-pressure reactor equipped with a magnetic stirrer. First, 50 mg of 0.5Pd0.1Ni / ZnO catalyst, 1 mmol of furfural, and 5 mL of water were added to the stainless steel high-pressure reactor with a quartz liner, and a magnetic stirrer was added. After loading the reactor, the gas in the reactor was replaced three times with hydrogen gas at 2-3 MPa to remove the air in the reactor. The temperature was raised to the specified temperature of 180 ℃ using an automatic temperature controller, and then hydrogen gas was introduced to the pressure of 1 MPa. The stirring was turned on to start the reaction. The reaction was stopped after 3 hours. The reactor was placed in ice water to cool rapidly to room temperature, and the catalyst and reaction solution were separated by centrifugation. (5) Sampling and analysis: The product was qualitatively identified by comparing the gas chromatographic retention time of the standard substance cyclopentanone with the gas chromatographic retention time of the gas chromatographic mass spectrometry (GC-MS). The main product was identified as cyclopentanone. The quantitative analysis was performed by the external standard method of gas chromatography.

9. The method for preparing cyclopentanone by highly selective hydrogenation of furfural as a raw material according to claim 8, characterized in that: The reaction was carried out with 50 mg of 0.5Pd0.1Ni / ZnO catalyst, 1 mmol of furfural, and 5 mL of water at 1 MPa H2 and 180 °C for 3 h. The furfural conversion and cyclopentanone selectivity reached 95% and 92.24%, respectively, and the yield reached 87.63%.

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