Method for preparing cyclopentanone by using furfural as raw material through high-selectivity hydrogenation

Abstract

The invention provides a method for preparing cyclopentanone by using furfural as a raw material through high-selectivity hydrogenation. According to the method, a biomass derivative furfural is taken as a raw material, in a low hydrogen pressure atmosphere, in the presence of a metal supported catalyst, water is taken as a solvent, and cyclopentanone is obtained in one step through a hydrogenation rearrangement reaction in a high-pressure reaction kettle. The metal supported catalyst is prepared from active metal palladium and transition metal Ni through a co-impregnation method. The obtained catalyst has the advantages of high metal dispersity, strong heat and mass transfer capability, convenience in recovery and separation, high efficiency, good stability and the like, and has important significance on economic production of chemicals. After the reaction is carried out for 3 hours under the conditions of 1 MPa H2 and 180 DEG C, the furfural conversion rate and the cyclopentanone selectivity respectively reach 95% and 92.24%, and the yield reaches 87.63%. The reaction process conditions are mild, the raw materials are cheap and easy to obtain, quantitative conversion from furfural to cyclopentanone can be realized in a water phase, and the method belongs to an environment-friendly green chemical process.

Description

Technical Field

[0001] The invention belongs to the technical field of catalytic synthesis, and specifically relates to a method for preparing cyclopentanone from a bio-based raw material furfural by aqueous phase hydrogenation, and also relates to a catalyst for cyclopentanone synthesis and a preparation method thereof, wherein the catalyst can efficiently catalyze the selective hydrogenation of furfural to prepare cyclopentanone. Background Art

[0002] The rapid reduction of fossil resources and the increasing level of greenhouse gas emissions have brought great challenges to mankind in terms of energy crisis and environmental pollution. In order to cope with these problems, people are developing and utilizing renewable energy as sustainable chemical raw materials. 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 is used to produce various derivatives and downstream products such as cyclopentanone, cyclopentanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, 2-methylfuran, furan and pentanediol by hydrogenation using suitable catalysts. Among these compounds, cyclopentanone is an important fine chemical intermediate and an important raw material for the fragrance and pharmaceutical industries. Cyclopentanone can be used to prepare a variety of anti-inflammatory and anticancer drugs such as jasmone, cyclopentanone, 2-n-hexylcyclopentanone, and can also be used to synthesize pesticides, herbicides and rubber synthesis. At the same time, due to its good solubility in various resins, cyclopentanone has also been widely used as a solvent in the electronics industry.

[0003] At present, the main industrial production method of cyclopentanone is adipic acid pyrolysis (such as Chinese patent CN 1594259, European patent EP 306873). However, the raw materials for preparing cyclopentanone by this route depend on the production of oxalic acid, which involves many steps, and involves a decarboxylation process in the production process, with a relatively low theoretical mass yield and low atom economy. In addition, the cyclopentene oxidation method is another technical route for preparing cyclopentanone (such as patents JP04312549, WO 349.73078372, WO349.76032532), which generally uses a Wacker type oxidation catalyst, or uses N2O as an oxidant to directly react with cyclopentene to produce cyclopentanone. Although the reaction effect is good (yield: 70-75%), the system mainly uses palladium chloride and copper chloride as active ingredients, resulting in the generation of chlorine-containing by-products during the reaction, which not only has a large corrosive effect on the reaction equipment, but also causes the generation of by-products. Moreover, the oxidation method using N2O as an oxidant is generally carried out at high temperature (280°C) and high pressure (30MPa), and the reaction conditions are harsh. Therefore, it is of great significance to develop new raw materials and new routes for the preparation of cyclopentanone, especially to utilize cheap and abundant biomass resources.

[0004] Furfural is a biomass-derived material. In industry, it is mass-produced using cheap agricultural and forestry waste (such as corn cobs, bagasse, cottonseed hulls, etc.) as raw materials. Furfural and cyclopentanone both have five carbon atoms, so the direct conversion of furfural into cyclopentanone has important application value. In recent years, the hydrogenation and 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), and achieved the purpose of converting furfural into cyclopentanone by changing the distribution of acidic sites and adjusting the hydrogenation activity of metal sites. However, the catalyst preparation method is complicated, and the phosphorus introduced during the preparation of the catalyst will also produce waste liquid, so it is not suitable for large-scale production. Chinese patent CN110041168 synthesizes 10% Co-10% Ni / TiO2 bimetallic catalyst by excess impregnation method to catalyze furfural aqueous phase hydrogenation rearrangement to prepare cyclopentanone. The reaction can reach 100% furfural conversion and 51% cyclopentanone selectivity at 6 MPa H2 and 140 °C for 4 h. However, the high reaction pressure and low cyclopentanone selectivity still limit its large-scale production.

[0005] Therefore, the development of a green and efficient heterogeneous catalyst for the highly selective preparation of cyclopentanone from furfural in an aqueous phase under low pressure conditions has a good industrial application prospect. Summary of the invention

[0006] The invention overcomes the defects of the prior art and provides a method for preparing cyclopentanone by taking furfural, a biomass resource, as a raw material, which has mild reaction conditions, good selectivity, high product yield and is green and environmentally friendly.

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

[0008] 1. The catalyst synthesis process equipment is simple to operate, has fewer steps, is safe to operate, and is pollution-free. It can meet the needs of large-scale production, save costs, and has high economic benefits;

[0009] 2. The prepared catalyst has good catalytic performance;

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

[0011] In order to solve the technical problem of the present invention, the proposed technical solution is: a method for preparing cyclopentanone by highly selective hydrogenation using 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 incipient wetness co-impregnation method. The main active component of the catalyst was palladium, and nickel was used as a co-catalyst component. The mass ratio of the two metals was Pd:Ni = 5:1, wherein the mass fraction of metal palladium was 0.5 wt%, the mass fraction of metal nickel was 0.1 wt%, and the mass fraction of carrier ZnO was 99.4%. The preparation method was to dissolve a certain mass of metal salt, calculated based on the loading amount of the catalyst, in an appropriate amount of deionized water, and oscillate and ultrasonicate to disperse the metal ions uniformly in the water. Subsequently, the obtained metal precursor mixed solution was uniformly dripped onto the ZnO carrier, ground until fully impregnated, and then placed in a drying oven at 60-90 °C for 9-12 h. The dried catalyst was placed in a tubular furnace and calcined and reduced at 250-450 °C with hydrogen for 2-4 h. h, and then take it out after cooling down to obtain the metal-supported 0.5Pd0.1Ni / ZnO catalyst, which is then stored in a drying cabinet;

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

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

[0015] Preferably, the metal-supported catalyst is a 0.5Pd0.1Ni / ZnO catalyst, and a palladium-nickel bimetallic catalyst is synthesized by the incipient wetness co-impregnation method, wherein the main active component is palladium, and nickel is the co-catalyst component; the mass ratio of the two metals is Pd:Ni = 5:1, wherein the mass fraction of metal palladium is 0.5 wt%, the mass fraction of metal nickel is 0.1 wt%, and the mass fraction of carrier ZnO 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 tubular furnace and calcined and reduced at 250-450° C. for 2-4 h in hydrogen gas 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; usually, a magnet 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 loaded and pressurized, and the reaction is carried out in cooperation 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 kettle is opened, the mixture is filtered, and the mixture is tested.

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

[0020] (1) Preparation of palladium-based bimetallic supported catalyst: The active component and auxiliary agent of the catalyst are the metal precursor salt solution. Palladium nitrate dihydrate and nickel nitrate hexahydrate are selected. 5 g of palladium nitrate dihydrate Pd(NO3)2·2H2O is dissolved in 100 mL of deionized water to prepare a palladium precursor solution Pd: 7.149 mg / mL for use; 2.4664 g of nickel nitrate hexahydrate Ni(NO3)2·6H2O is dissolved in 50 mL of deionized water to prepare a nickel precursor solution Ni: 10 mg / mL for 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 it before, then add 45.8 μL of nickel precursor solution and an appropriate amount of deionized water, sonicate for 5 min to mix them evenly, drop the mixed solution evenly onto the ZnO support, grind until the catalyst is fully impregnated, and dry it in a 70 °C drying oven for 12 h.

[0022] (3) The impregnated and dried catalyst was taken out and ground into uniform fine particles, and then loaded into a tubular furnace, with quartz wool placed above and below the catalyst bed; the temperature was raised from room temperature to 350°C at a rate of 5°C / min under a hydrogen flow rate of 40 mL / 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 taken out to obtain a 0.5Pd0.1Ni / ZnO catalyst;

[0023] (4) The hydrogenation rearrangement reaction of furfural is carried out in a stainless steel autoclave equipped with a magnetic stirrer. First, 50 mg of 0.5Pd0.1Ni / ZnO catalyst, 1 mmol of furfural, and 5 mL of water are added to a stainless steel autoclave with a quartz lining, and a magnet is added. After the autoclave is loaded, the gas in the autoclave is replaced three times with 2-3 MPa of hydrogen to remove the air in the reactor. The temperature is raised to a specified temperature of 180 °C using an automatic temperature controller, and then hydrogen is charged to a pressure of 1 MPa, and stirring is turned on to start the reaction. The reaction ends after 3 hours, and the autoclave is quickly cooled to room temperature in ice water, and the catalyst and reaction liquid are separated by centrifugation.

[0024] (5) Sampling and analysis: the product was qualitatively determined by comparing the gas chromatography retention time of the standard substance cyclopentanone with that of gas chromatography-mass spectrometry (GC-MS), and the main product was qualitatively determined to be cyclopentanone; the gas chromatography external standard method was used for quantitative determination.

[0025] The method for converting furfural into cyclopentanone using furfural as a raw material provided by the present invention needs to consider the steps of catalytic hydrogenation and rearrangement, so it is necessary to design a catalyst system with different functions, such as a catalyst carrier, an active component and an auxiliary component. The designed catalyst is a bimetallic supported catalyst. The carrier used by the catalyst is one of Al2O3, MgO, ZnO, SiO2, ZrO2 and TiO2. The catalyst active component is Pd, and the auxiliary agent is one of Cr, Ni, Fe, Co and Cu. The mass ratio of the auxiliary loading to the active component is 0.0-5.0:1.

[0026] The present invention provides the following technical solution: a method for preparing cyclopentanone by high-selective hydrogenation using furfural as a raw material, comprising the following steps:

[0027] (1) Preparation of metal-supported catalysts: Dissolve a certain amount of metal salt (calculated based on the loading amount of the catalyst) in an appropriate amount of deionized water according to the proportion, and oscillate and ultrasonicate to disperse the metal ions evenly in the water; then, drop the obtained metal precursor mixed solution evenly onto the carrier, grind until the carrier is fully impregnated, and then place it in a drying oven at 60-90°C for 9-12 hours; place the dried catalyst in a tubular furnace, calcine and reduce it with hydrogen at 250-450°C for 2-4 hours, take it out after cooling, and obtain a supported palladium-based bimetallic catalyst, which is then placed in a drying oven for storage;

[0028] (2) Preparation of cyclopentanone using furfural as raw material: The hydrogenation rearrangement reaction of furfural is carried out in a stainless steel high-pressure reactor equipped with a magnetic stirrer. Usually, the reaction raw materials, solvent and catalyst are added to the reactor; the reactor is loaded and pressurized, and the reaction is carried out in cooperation with a temperature controller and a magnetic stirrer; before the reaction, the reactor is purged with hydrogen several times to remove the air in the device; the reaction solvent is 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 is 0.1 - 4 MPa; the reaction temperature is 150 - 210 ℃; the reaction time is 30 - 240 min; after the reaction is completed, the temperature is lowered, the pressure is released, the reactor is opened, filtered, and tested;

[0029] A high-performance supported metal catalyst is selected from palladium and another transition metal, and is loaded on a carrier by a co-impregnation method. The catalyst active component is Pd, and the transition metal is added to the palladium-based catalyst as a promoter. The transition metal is selected from one of Cr, Ni, Fe, Co, Cu, etc. The precursors of the transition metal are all metal salt solutions thereof.

[0030] The carrier is one of Al2O3, MgO, ZnO, SiO2, ZrO2 and TiO2; the preferred carrier is ZnO.

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

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

[0033] The principle of the present invention is as follows:

[0034]

[0035] Beneficial effects:

[0036] The present invention uses abundant and cheap biomass derivative furfural as a raw material to prepare cyclopentanone by a one-pot method, which has a simplified process, mild reaction conditions, reduced production costs, high overall yields, and high added value of hydrogenated products. In the method provided by the present invention, the conversion of furfural into cyclopentanone is carried out in an aqueous medium. Water is a cheap and abundant green solvent in nature. Using water to replace organic solvents is beneficial to reducing production costs and environmental protection. The active component of the supported metal catalyst provided by the present invention has a high hydrogenation active center and exists stably in the aqueous phase. At the same time, the carrier provides a weak Lewis acid center, and the PdNi bimetallic and the carrier cooperate with each other, which is beneficial to improving the conversion rate of furfural and its derivatives and the selectivity of cyclopentanone compounds. In particular, under the conditions of 180°C and 1MPa low hydrogen pressure, the 0.5Pd0.1Ni / ZnO catalyst in the aqueous phase exhibits excellent activity, the furfural conversion rate is 95%, the cyclopentanone selectivity is 92.24%, and the yield reaches 87.63%. Under similar conditions, the yield is better than most catalysts currently reported.

[0037] Compared with the PtCoSiO2 supported metal catalyst used in the preparation of cyclopentanone from furfural in Chinese patent CN114605246B, the supported metal catalyst provided by the present invention has obvious advantages in activity and economic benefits at a lower precious metal loading and can achieve higher cyclopentanone selectivity.

[0038] In addition, both the raw material furfural and the product cyclopentanone are C5 compounds, and there is no loss of carbon during the reaction process, which has a high atom economy. The conversion from furfural to cyclopentanone can be completed in a reactor in one step or in a fixed bed reactor, without the need to separate intermediate products. Compared with the existing process production technology, the present invention has the following obvious advantages: the preparation process is simple, no external acid or alkaline additives are required, the raw materials are renewable, the catalyst has high activity and stability, the reaction conditions are milder, the energy consumption is reduced to a certain extent, and it is more environmentally friendly, which can partially alleviate the energy problems facing the world today. Therefore, the present invention has broad application potential in industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0040] Figure 2 Effects of different metal additives on the reaction activity

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

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

[0043] Figure 5 The effect of reaction temperature on product distribution

[0044] Figure 6 The effect of reaction pressure on product distribution

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

[0046] Figure 8 Effect of mixed solvent on product distribution

[0047] Fig. 9 The effect of reaction time on product distribution

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

[0049] Fig.11 Reaction pathway for the preparation of cyclopentanone from furfural DETAILED DESCRIPTION

[0050] The present invention is further described in detail below in conjunction with 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 metal palladium. Here, we take the preferred palladium nitrate dihydrate as an example. Take 5 g of palladium nitrate dihydrate Pd(NO3)2·2H2O and dissolve it in 100 mL of deionized water to prepare a palladium precursor solution (Pd: 7.149 mg / mL) for use;

[0053] (2) Weigh 497.5 mg of ZnO carrier and spread it evenly on a mortar. Take 349.7 μL of palladium precursor solution, oscillate and sonicate it, then add an appropriate amount of deionized water to just wet the carrier. Sonicate for 5 min, drop the metal palladium precursor solution evenly onto the ZnO carrier, grind until the catalyst is fully impregnated, and dry it in a 70 °C drying oven for 12 h.

[0054] (3) The impregnated and dried catalyst was taken out and ground into uniform fine particles, and then loaded into a tubular furnace, with quartz wool placed above and below the catalyst bed. Under a hydrogen flow (flow rate of 40 mL / min), the temperature was raised 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 taken out to obtain a 0.5wt% Pd / ZnO catalyst;

[0055] (4) The hydrogenation rearrangement reaction of furfural was carried out in a stainless steel autoclave 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 a stainless steel autoclave with a quartz liner, and a magnet was added. After loading the autoclave, the gas in the autoclave was replaced three times with 2-3 MPa of hydrogen to remove the air in the reactor. The temperature was raised to the specified temperature of 160 °C using an automatic temperature controller, and then hydrogen was charged to a pressure of 1 MPa, and stirring was turned on to start the reaction. The reaction ended after 3 h, and the autoclave was quickly cooled to room temperature in ice water, and the catalyst and reaction liquid were separated by centrifugation.

[0056] (5) Sampling and analysis: the qualitative analysis of the product was conducted by comparing the gas chromatography retention time of the standard substance (cyclopentanone) with that of the gas chromatography mass spectrometer (GC-MS). The main product was identified as cyclopentanone. The quantitative analysis was conducted by using the gas chromatography external standard method.

[0057] Example 2

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

[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 it before, then add 45.8 μL of nickel precursor solution and an appropriate amount of deionized water, sonicate for 5 min to mix them evenly, drop the mixed solution evenly onto the ZnO support, grind until the catalyst is fully impregnated, and dry it in a 70 °C drying oven for 12 h.

[0060] (3) The impregnated and dried catalyst was taken out and ground into uniform fine particles, and then loaded into a tubular furnace, with quartz wool placed above and below the catalyst bed. Under a hydrogen flow (flow rate of 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 taken out to obtain a 0.5Pd0.1Ni / ZnO catalyst. The mass ratio of the two metals is Pd:Ni = 5:1, in which the mass fraction of palladium and nickel is 0.6 wt% each, and the mass fraction of the carrier ZnO is 99.4%;

[0061] (4) The hydrogenation rearrangement reaction of furfural is carried out in a stainless steel autoclave equipped with a magnetic stirrer. First, 50 mg of 0.5Pd0.1Ni / ZnO catalyst, 1 mmol of furfural, and 5 mL of water are added to a stainless steel autoclave with quartz, and a magnet is added. After loading the autoclave, the gas in the autoclave is replaced three times with 2-3 MPa of hydrogen to remove the air in the reactor. The temperature is raised to the specified temperature of 160 °C using an automatic temperature controller, and then hydrogen is charged to a pressure of 1 MPa, and stirring is turned on to start the reaction. The reaction ends after 3 h, and the autoclave is quickly cooled to room temperature in ice water, and the catalyst and reaction liquid are separated by centrifugation.

[0062] (5) Sampling and analysis: the qualitative analysis of the product was conducted by comparing the gas chromatography retention time of the standard substance (cyclopentanone) with that of the gas chromatography mass spectrometer (GC-MS). The main product was identified as cyclopentanone. The quantitative analysis was conducted by using the gas chromatography external standard method.

[0063] Example 3

[0064] Investigating the effect of temperature on the preparation of cyclopentanone by hydrogenation of furfural: This example is different from Example 2 in that the reaction temperature in step (4) is 150 °C, and the other processes are the same as Example 2.

[0065] Example 4

[0066] Investigating the effect of temperature on the preparation of cyclopentanone by hydrogenation of furfural: This example is different from Example 2 in that the reaction temperature in step (4) is 170 °C, and the other processes are the same as Example 2.

[0067] Example 5

[0068] Investigating the effect of temperature on the preparation of cyclopentanone by hydrogenation of furfural: This example is different from Example 2 in that the reaction temperature in step (4) is 180°C, and the other processes are the same as Example 2.

[0069] Example 6

[0070] Investigating the effect of temperature on the preparation of cyclopentanone by hydrogenation of furfural: This example is different from Example 2 in that the reaction temperature in step (4) is 190°C, and the other processes are the same as Example 2.

[0071] Example 7

[0072] Investigating the effect of temperature on the preparation of cyclopentanone by hydrogenation of furfural: This example is different from Example 2 in that the reaction temperature in step (4) is 200 °C, and the other processes are the same as Example 2.

[0073] Example 8

[0074] Investigating the effect of temperature on the preparation of cyclopentanone by hydrogenation of furfural: This example is different from Example 2 in that the reaction temperature in step (4) is 210 °C, and the other processes are the same as Example 2.

[0075] Example 9

[0076] Investigate the effect of pressure on the hydrogenation of furfural to produce cyclopentanone:

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

[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 it before, then add 45.8 μL of nickel precursor solution and an appropriate amount of deionized water, sonicate for 5 min to mix them evenly, drop the mixed solution evenly onto the ZnO support, grind until the catalyst is fully impregnated, and dry it in a 70 °C drying oven for 12 h.

[0079] The impregnated and dried catalyst was taken out and ground into uniform fine particles, and then loaded into a tubular furnace, with quartz wool placed above and below the catalyst bed. Under a hydrogen flow (flow rate of 40 mL / min), the temperature was raised 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 taken out to obtain a 0.5Pd0.1Ni / ZnO catalyst; Fig.10 These are the XRD patterns of several catalysts used in the catalyst screening process and the best 0.5%Pd0.1%Ni-ZnO catalyst. It can be seen from the figure that with the reduction of the precious metal Pd loading and the doping of the base metal Ni, the dispersion of Pd becomes significantly higher.

[0080] (3) The hydrogenation rearrangement reaction of furfural was carried out in a stainless steel autoclave 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 autoclave with quartz, and a magnet was added. After loading the autoclave, the gas in the autoclave was replaced three times with 2-3 MPa of hydrogen to remove the air in the reactor, and then hydrogen was filled to 1 MPa. The temperature was raised to the specified temperature of 180 °C using an automatic temperature controller, and stirring was turned on to start the reaction. The reaction ended after 3 h, and the autoclave was quickly cooled to room temperature in ice water, and the catalyst and reaction liquid were separated by centrifugation.

[0081] (4) Sampling and analysis: The qualitative analysis of the product was conducted by comparing the gas chromatography retention time of the standard substance (cyclopentanone) with that of the gas chromatography mass spectrometer (GC-MS). The main product was identified as cyclopentanone. The quantitative analysis was conducted by using the gas chromatography external standard method.

[0082] Example 10

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

[0084] Embodiment 11

[0085] Investigating the effect of pressure on the preparation of cyclopentanone by hydrogenation of furfural: This example is different from Example 9 in that the reaction pressure in step (4) is 0.5 MPa, and the other processes are the same as Example 9.

[0086] Example 12

[0087] Investigating the effect of pressure on the preparation of cyclopentanone by hydrogenation of furfural: This example is different from Example 9 in that the reaction pressure in step (4) is 1.5 MPa, and the other processes are the same as Example 9.

[0088] Embodiment 13

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

[0090] Embodiment 14

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

[0092] Embodiment 15

[0093] Investigating the effect of reaction solvent on the preparation of cyclopentanone by hydrogenation of furfural: This example is different from Example 9 in that the reaction solvent in step (4) is methyl isobutyl ketone, and the other processes are the same as Example 15.

[0094] Embodiment 17

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

[0096] Embodiment 18

[0097] Investigating the effect of reaction solvent on the hydrogenation of furfural to prepare cyclopentanone: This example is different from Example 9 in that the reaction solvent in step (4) is methanol, and the other processes are the same as Example 15.

[0098] Embodiment 19

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

[0100] Embodiment 20

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

[0102] Embodiment 21

[0103] Catalyst stability experiment: The operation steps of this example are the same as those of Example 9, but the catalyst is repeatedly washed with ethanol and dried after the first reaction. The yield of cyclopentanone obtained by the second application is 83%.

[0104] Embodiment 22

[0105] Catalyst stability experiment: The operation steps of this example are the same as those of Example 9, but the catalyst is repeatedly washed with ethanol and dried after the second reaction. The yield of cyclopentanone obtained by the third application is 84%.

[0106] Embodiment 23

[0107] Catalyst stability experiment: The operation steps of this example are the same as those of Example 9, but the catalyst is repeatedly washed with ethanol and dried after the third reaction. The yield of cyclopentanone obtained by the fourth application is 81%.

[0108] Embodiment 24

[0109] Catalyst stability experiment: The operation steps of this example are the same as those of Example 9, but the catalyst is repeatedly washed with ethanol and dried after the fourth reaction. The yield of cyclopentanone obtained by the fifth application is 79%.

[0110] Comparative Example 1

[0111] (1) Influence of catalyst components: By replacing the auxiliary component Ni in Example 9 with any one of transition metals such as Co, Fe, Cu, and Cr, and using ZnO as a carrier, 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 components and auxiliary agents of the catalyst are both metal precursor salt solutions. 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 2.4774g 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.

[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 it before, then add 45.8 μL of nickel precursor solution and an appropriate amount of deionized water, sonicate for 5 min to mix them evenly, drop the mixed solution evenly onto the ZnO support, grind until the catalyst is fully impregnated, and dry it in a 70 °C drying oven for 12 h.

[0113] (3) The impregnated and dried catalyst was taken out and ground into uniform fine particles, and then loaded into a tubular furnace, with quartz wool placed above and below the catalyst bed. Under a hydrogen flow (flow rate of 40 mL / min), the temperature was raised 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 taken out to obtain a 0.5Pd0.1Ni / ZnO catalyst;

[0114] (4) The hydrogenation rearrangement reaction of furfural was carried out in a stainless steel autoclave 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 autoclave with a polytetrafluoroethylene liner, and a magnet was added. After loading the autoclave, the gas in the autoclave was replaced three times with 2-3 MPa of hydrogen to remove the air in the reactor. The temperature was raised to the specified temperature of 180 °C using an automatic temperature controller, and then hydrogen was charged to a pressure of 1 MPa, and stirring was turned on to start the reaction. The reaction ended after 3 h, and the autoclave was quickly cooled to room temperature in ice water, and the catalyst and reaction liquid were separated by centrifugation.

[0115] (5) Sampling and analysis: the qualitative analysis of the product was carried out by comparing the gas chromatography retention time of GC-MS and the standard substance (cyclopentanone), and the main product was identified as cyclopentanone. The quantitative analysis was carried out by the gas chromatography external standard method.

[0116] (6) Performance of furfural hydrogenation to cyclopentanone with different catalyst components. 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 carrier and spread it evenly on a mortar. Take 45.8 μL of nickel precursor solution, shake and sonicate it, then add an appropriate amount of deionized water to just wet the carrier. Sonicate for 5 min, drop the metal nickel precursor solution evenly onto the ZnO carrier, grind until the catalyst is fully impregnated, and dry it in a 70 °C drying oven for 12 h.

[0120] (3) The impregnated and dried catalyst was taken out and ground into uniform fine particles, and then loaded into a tubular furnace, with quartz wool placed above and below the catalyst bed. Under a hydrogen flow (flow rate of 40 mL / min), the temperature was raised 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 taken out to obtain a 0.1wt.% Ni / ZnO catalyst;

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

[0122] (5) Sampling and analysis: the qualitative analysis of the product was carried out by comparing the gas chromatography retention time of GC-MS and the standard substance (cyclopentanone), and the main product was identified as cyclopentanone. The quantitative analysis was carried out by the gas chromatography external standard method.

[0123] Comparative Example 3

[0124] Influence of carrier: By changing the carrier in Example 1 to Al2O3, MgO, SiO2, TiO2 and ZrO2, Pd / Al2O3, Pd / MgO, Pd / SiO2, Pd / TiO2 and Pd / ZrO2 catalysts can be obtained. The rest is the same as Example 1. The performance reaction results of furfural hydrogenation to cyclopentanone on different carriers are shown in Figure 1

[0125] Comparative Example 4

[0126] Effect of the loading amount of the auxiliary metal Ni: The percentage of the auxiliary component Ni in Example 9 is changed to 0, 0.3, 0.5, 0.7, 1.0, 3.0, 5.0, 7.0. With ZnO as the preferred carrier, Pd / ZnO, PdNi 0.3 / ZnO,PdNi 0.5 / ZnO, PdNi 0.7 / ZnO, PdNi1 / ZnO, PdNi3 / ZnO, PdNi5 / ZnO. Others are the same as in Example 9. The effect of metal Ni loading on the hydrogenation performance of furfural to prepare cyclopentanone is 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 is changed to 30 min, 60 min, 90 min, 120 min, 150 min, 180 min, 210 min, 240 min. The rest is the same as Example 9. The reaction results are shown in Fig. 9 .

[0130] Comparative Example 6

[0131] Different proportions of ethanol and water were mixed as solvents to carry out experiments on the hydrogenation of furfural to cyclopentanone. The total volume of the solution was kept constant, and the ratios of ethanol to water were 100:0, 75:25, 50:50, 25:75, and 0:100 respectively; the reaction results are shown in Figure 7 , proving that solvent water is crucial to the production of cyclopentanone.

[0132] according to Figure 1 , we investigated the effect of Pd single metal loading on different supports on the reaction activity. 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. First, several representative supports were selected according to the acidity and alkalinity of the support; such as acidic or weakly acidic oxide SiO2; basic oxides ZnO, MgO; and amphoteric oxide Al2O3. According to the reaction results, ZnO as a support is most conducive to the hydrogenation of furfural to prepare cyclopentanone.

[0133] according to Figure 2 The experimental results show that the selectivity of cyclopentanone can be improved to a certain extent by introducing the auxiliary component nickel on the palladium single metal catalyst with ZnO as the preferred carrier. The conversion rate of furfural on the 0.5Pd0.1Ni / ZnO catalyst is 95%, the selectivity of cyclopentanone is 92.24%, and the yield reaches 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 the auxiliary nickel may cause the metal particles to aggregate on the carrier, which is not conducive to the hydrogenation of furfural to prepare cyclopentanone.

[0135] according to Figure 5 , showing the effect of reaction temperature on product distribution. At low temperatures (<120 °C), the reaction mainly produces furfuryl alcohol. As the temperature increases, the yield of cyclopentanone increases and reaches a maximum at 180 °C. Further increasing the reaction temperature, cyclopentanone is over-hydrogenated to cyclopentanol.

[0136] according to Figure 6 The results show the effect of reaction pressure on product distribution. As the pressure increases (0-1 MPa), the selectivity of cyclopentanone increases and reaches the highest at 1 MPa. When the reaction pressure is further increased (>1 MPa), cyclopentanone is over-hydrogenated to cyclopentanol.

[0137] Figure 7 and Figure 8 It shows that the choice of solvent is critical to the liquid phase hydrogenation of furfural. In particular, the solvent water plays a vital role in the process of furfural hydrogenation rearrangement to prepare cyclopentanone.

[0138] Fig. 9 The effect of reaction time on product distribution was demonstrated. As the reaction time increased from 30 min to 3 h, the yield of cyclopentanone gradually increased to the maximum. When the reaction time was further extended to 240 min, cyclopentanone was partially hydrogenated to cyclopentanol.

[0139] According to the reaction results and related characterizations, the present invention studied the reaction of furfural hydrogenation rearrangement to prepare cyclopentanone by palladium-nickel bimetallic catalysis on six common supports under mild reaction conditions. A simple and reproducible method was developed to support metal loading on ZnO. By optimizing the reaction conditions, it was found that on the optimized 0.5Pd0.1Ni / ZnO catalyst, furfural can be completely converted in the aqueous phase at 180 °C under a low hydrogen pressure of 1 MPa. The conversion rate of furfural was 95%, the selectivity of cyclopentanone was as high as 92.24%, and the yield reached 87.63%. In the current catalytic system, the surface synergy between the basic center and the metal species on the 0.5Pd0.1Ni / ZnO catalyst greatly promoted the rearrangement of the intermediates of furfural, thereby forming a high-yield target cyclopentanone product. These findings provide a high-performance metal-supported catalyst for the conversion of furfural into cyclopentanone in the aqueous phase. This readily available, efficient and stable metal-supported heterogeneous catalyst has broad industrial application prospects. At the same time, compared with the traditional process production route, the process route of the invention has a simple preparation process, does not require external acid or alkaline additives, the raw materials are renewable, the reaction conditions are milder, and it reduces energy consumption to a certain extent. It is more environmentally friendly and can partially alleviate the energy problems facing the world today.

[0140] The present invention is not limited to the specific technical solutions described in the above embodiments, and all technical solutions formed by equivalent replacement are within the protection scope required by the present invention.

Claims

1. A method for preparing cyclopentanone by high-selective hydrogenation using furfural as a raw material, characterized in that: The following steps are involved: (1) Preparation of metal-supported catalyst 0.5Pd0.1Ni / ZnO: A 0.5Pd0.1Ni / ZnO catalyst was synthesized by incipient wetness co-impregnation method. The main active component of the catalyst was palladium, and nickel was used as a co-catalyst. The mass ratio of the two metals was Pd:Ni = 5:1, wherein the mass fraction of metal palladium was 0.5 wt%, the mass fraction of metal nickel was 0.1 wt%, and the mass fraction of carrier ZnO was 99.4%. The preparation method was as follows: a certain mass of metal salt, calculated based on the loading amount of the catalyst, was dissolved in an appropriate amount of deionized water, and the metal ions were uniformly dispersed in the water by oscillation and ultrasound. Subsequently, the obtained metal precursor mixed solution was uniformly added to the carrier ZnO, ground until fully impregnated, and then placed in a drying oven at 60-90 °C for 9-12 h. The dried catalyst was placed in a tubular furnace and calcined and reduced at 250-450 °C with hydrogen for 2-4 h. h, and then take it out after cooling down to obtain the metal-supported 0.5Pd0.1Ni / ZnO catalyst, which is then stored in a drying cabinet; (2) Preparation of cyclopentanone using furfural as raw material: The hydrogenation rearrangement reaction of furfural is carried out in a stainless steel high-pressure reactor equipped with a magnetic stirrer. The reaction raw material furfural, solvent water and catalyst metal-loaded 0.5Pd0.1Ni / ZnO are added to the reactor; the reactor is loaded and pressurized, and the reaction is carried out in the cooperation of a temperature controller and a magnetic stirrer; before the reaction, the reactor is purged with hydrogen several times to remove the air in the device; the reaction solvent is water; the initial hydrogen pressure is 0.5-1.0MPa; the reaction temperature is 160-180℃; and the reaction time is 120-180min.

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

3. The method for preparing cyclopentanone by high selective hydrogenation using furfural as a raw material according to claim 1, characterized in that: The metal-supported catalyst is a 0.5Pd0.1Ni / ZnO catalyst, and a palladium-nickel bimetallic catalyst is synthesized by an incipient wetness co-impregnation method, wherein the main active component is palladium, and nickel is used as a co-catalyst component; the mass ratio of the two metals is Pd:Ni = 5:1, wherein the mass fraction of metal palladium is 0.5 wt%, the mass fraction of metal nickel is 0.1 wt%, and the mass fraction of carrier ZnO 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 high selective hydrogenation using 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 tubular furnace and calcined and reduced with hydrogen at 350 °C for 4 h for activation treatment.

5. The method for preparing cyclopentanone by high selective hydrogenation using 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; usually, a magnet 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 loaded and pressurized, and the reaction is carried out in the cooperation of a temperature controller and a magnetic stirrer.

6. The method for preparing cyclopentanone by high selective hydrogenation using 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 kettle is opened, the mixture is filtered, and the mixture is tested.

7. The method for preparing cyclopentanone by high selective hydrogenation using furfural as a raw material according to claim 1, characterized in that: In step (2), after the reaction is completed, the reactor is placed in ice water and cooled to room temperature, and then the catalyst and the reaction liquid are separated by centrifugation; the product can be identified by gas chromatography-mass spectrometry GC-MS; and the conversion rate of furfural and the yield of cyclopentanone are calculated by gas chromatography analysis; in addition, the filtered catalyst powder can be continuously rinsed with ethanol and dried for recycling.

8. The method for preparing cyclopentanone by high selective hydrogenation using furfural as a raw material according to claim 1, characterized in that: (1) Preparation of palladium-based bimetallic supported catalyst: The active component and auxiliary agent of the catalyst are the metal precursor salt solution. Palladium nitrate dihydrate and nickel nitrate hexahydrate are selected. 5 g of palladium nitrate dihydrate Pd(NO3)2·2H2O is 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 is 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 it before, then add 45.8 μL of nickel precursor solution and an appropriate amount of deionized water, sonicate for 5 min to mix them evenly, drop the mixed solution evenly onto the ZnO support, grind until the catalyst is fully impregnated, and dry it in a 70 °C drying oven for 12 h. (3) The impregnated and dried catalyst was taken out and ground into uniform fine particles, and then loaded into a tubular furnace, with quartz wool placed above and below the catalyst bed; the temperature was raised from room temperature to 350°C at a rate of 5°C / min under a hydrogen flow rate of 40 mL / 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 taken out to obtain a 0.5Pd0.1Ni / ZnO catalyst; (4) The hydrogenation rearrangement reaction of furfural is carried out in a stainless steel autoclave equipped with a magnetic stirrer. First, 50 mg of 0.5Pd0.1Ni / ZnO catalyst, 1 mmol of furfural, and 5 mL of water are added to a stainless steel autoclave with a quartz lining, and a magnet is added. After the autoclave is loaded, the gas in the autoclave is replaced three times with 2-3 MPa of hydrogen to remove the air in the reactor. The temperature is raised to a specified temperature of 180 °C using an automatic temperature controller, and then hydrogen is charged to a pressure of 1 MPa, and stirring is turned on to start the reaction. The reaction ends after 3 hours, and the autoclave is quickly cooled to room temperature in ice water, and the catalyst and reaction liquid are separated by centrifugation. (5) Sampling and analysis: the product was qualitatively determined by comparing the gas chromatography retention time of the standard substance cyclopentanone with that of gas chromatography-mass spectrometry (GC-MS), and the main product was qualitatively determined to be cyclopentanone; the gas chromatography external standard method was used for quantitative determination.

9. The method for preparing cyclopentanone by high-selective hydrogenation using furfural as a raw material according to claim 8, characterized in that: 50 mg 0.5Pd0.1Ni / ZnO catalyst, 1 mmol furfural, 5 mL water were added; after reacting at 1 MPa H2, 180 °C for 3 h, the furfural conversion rate and cyclopentanone selectivity reached 95% and 92.24% respectively, and the yield reached 87.63%.

Images