CN114605246A

CN114605246A - Method for preparing cyclopentanone by high-selectivity hydrogenation with furfural as raw material

Info

Publication number: CN114605246A
Application number: CN202210408094.0A
Authority: CN
Inventors: 王川; 吴敏; 张钦; 陈凯琴; 李国佳
Original assignee: Nanjing Tech University
Current assignee: Nanjing Tech University
Priority date: 2022-04-19
Filing date: 2022-04-19
Publication date: 2022-06-10
Anticipated expiration: 2042-04-19
Also published as: CN114605246B

Abstract

The invention provides a method for preparing cyclopentanone by high-selectivity hydrogenation with furfural as a raw material. Specifically, the cyclopentanone is obtained by taking biomass derivative furfural as a raw material, taking water as a solvent in the presence of a metal supported catalyst in a low-hydrogen pressure atmosphere, and performing a hydrogenation rearrangement reaction in a high-pressure reaction kettle or a fixed bed reactor. The metal-supported catalyst is prepared by co-impregnating active metal platinum and transition metal. The catalyst obtained by the method has the advantages of high metal dispersity, strong heat and mass transfer capacity, convenience in recovery and separation, high efficiency, good stability and the like, and has important significance for economic production of chemicals. In addition, the invention is at 1MPa H₂And reacting for 3 hours at 180 ℃, wherein the furfural conversion rate and the cyclopentanone selectivity respectively reach 100% and 89%. Hair brushThe reaction process has mild conditions, cheap and easily available raw materials, can realize quantitative conversion from furfural to cyclopentanone in a water phase, and belongs to an environment-friendly green chemical process.

Description

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

Technical Field

The invention belongs to the technical field of catalytic synthesis, and particularly relates to a method for preparing cyclopentanone from a bio-based raw material furfural through aqueous phase hydrogenation, and in addition, relates to a catalyst for cyclopentanone synthesis and a preparation method thereof.

Background

The rapid reduction of fossil resources and the increasing levels of greenhouse gas emissions have created enormous challenges for human beings in terms of energy crisis and environmental pollution. In order to cope with these problems, development of renewable energy as a chemical raw material that can be continuously developed is under way. Biomass is a renewable resource and biomass-derived platform compounds can be converted into many valuable chemicals. Furfural is an important biomass platform compound used for the production of various derivatives and downstream products such as cyclopentanone, cyclopentanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, 2-methylfuran, furan, pentanediol and the like by hydrogenation using suitable catalysts. Of these compounds, cyclopentanone is an important intermediate in fine chemicals, an important raw material for the fragrance and pharmaceutical industries. The cyclopentanone can be used for preparing various anti-inflammatory and anticancer drugs such as jasmone, albonone, 2-n-hexyl cyclopentanone, and the like, and can also be used for synthesizing pesticides, herbicides and rubber. Meanwhile, cyclopentanone is widely used as a solvent in the electronic industry because of its good solubility in various resins.

At present, the industrial production method of cyclopentanone is mainly an adipic acid pyrolysis method (such as Chinese patent CN1594259 and European patent EP 306873), however, the raw material for preparing cyclopentanone by the route depends on the production of oxalic acid, the steps are more, and the decarboxylation process is involved in the production process, so that the theoretical mass yield is lower, and the atom economy is not high. Moreover, the cyclopentene oxidation process is another technical route for the preparation of cyclopentanone (for example, patent JP04312549, WO 2003078372, WO2006032532), generally using an oxidation catalyst of the Wacker type, or alternatively using N₂And O is used as an oxidizing agent and directly reacts with cyclopentene to generate cyclopentanone. Although the reaction effect is good (Yield: 70-75%), but the system mainly takes palladium chloride and copper chloride as active ingredients, which causes the generation of chlorine-containing byproducts in the reaction process, not only has great corrosion effect on reaction equipment, but also causes the generation of byproducts. And with N₂The oxidation method using O as an oxidizing agent is generally carried out at a high temperature (280 ℃) and a high pressure (30MPa), and the reaction conditions are severe. Therefore, the development of a new raw material and a new route for preparing cyclopentanone, particularly the utilization of cheap and rich biomass resources, has important significance.

Furfural is a biomass-derived material, and is industrially produced on a large scale from inexpensive agricultural and forestry wastes (such as corn cobs, bagasse, cottonseed hulls, and the like) as a raw material. The furfural and the cyclopentanone both have five carbon atoms, so that the furfural is directly converted into the cyclopentanone, and the application value is important. In recent years, the preparation of cyclopentanone by furfural hydrogenation rearrangement is also gradually a hot spot of biomass research. For example, Guoming Gao et Al introduced phosphorus into Ni/Al₂O₃In (Catal. Sci. Technol,2021,11: 575-. Chinese patent CN110041168 synthesizes 10 percent Co-10 percent Ni/TiO by excess dipping method₂The method for preparing cyclopentanone by catalyzing furfural aqueous phase hydrogenation rearrangement with a bimetallic catalyst at 6MPa H₂The reaction at 140 ℃ for 4h can achieve 100% furfural conversion and 51% cyclopentanone selectivity, but the large-scale production is still limited due to the large reaction pressure and the low cyclopentanone selectivity.

Therefore, a green and efficient heterogeneous catalyst is developed, and the process method for preparing cyclopentanone by catalyzing furfural with high selectivity under the conditions of water phase and low pressure has a good industrial application prospect.

Disclosure of Invention

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

The invention also provides a high-performance supported catalyst and a preparation method thereof, so as to realize the following purposes:

1. the catalyst synthesis process has the advantages of simple operation of equipment, fewer steps, safe operation, no pollution, capability of meeting the requirement of large-scale production, cost saving and high economic benefit;

2. the prepared catalyst has good catalytic performance;

3. the catalyst is applied to the preparation of cyclopentanone by furfural hydrogenation, can simultaneously avoid side reaction of the cyclohydrogenation and polymerization of furfural in the reaction process, improve the application times of the catalyst and simultaneously keep higher yield of cyclopentanone.

In order to solve the technical problem of the invention, the technical scheme is as follows: a method for preparing cyclopentanone by high-selectivity hydrogenation with furfural as a raw material comprises the following steps:

(1) preparation of Metal Supported catalyst PtCo/SiO 2: PtCo/SiO is synthesized by adopting an incipient wetness co-impregnation method₂The catalyst comprises a main active component of platinum and a co-catalyst component of cobalt; the mass ratio of the two metals is Pt to Co being 1:1, wherein the mass fraction of metal platinum is 1 wt%, the mass fraction of metal cobalt is 1 wt%, and the mass fraction of carrier SiO is₂The mass fraction is 98 percent; the preparation method comprises the steps of dissolving a certain mass of metal salt in a proper amount of deionized water based on the load calculation of a catalyst, and oscillating ultrasonic to uniformly disperse metal ions in water; then, the obtained metal precursor mixed solution is uniformly dripped into SiO₂Grinding the carrier until the carrier is fully soaked, and then putting the carrier into a drying oven at 60-90 ℃ for drying for 9-12 h; the dried catalyst is loaded into a tubular furnace, hydrogen is introduced at the temperature of 250-450 ℃ for calcination and reduction for 2-4h, and the catalyst is taken out after cooling to obtain the metal-loaded PtCo/SiO₂The catalyst is put into a drying cabinet for storage;

(2) preparing cyclopentanone by taking furfural as a raw material: the hydrogenation rearrangement reaction of furfural is carried out in a stainless steel high-pressure reaction kettle with a magnetic stirrer, and reaction raw materials of furfural, solvent water and catalyst metal-loaded PtCo/SiO are added into the reactor₂(ii) a Loading in a kettle, pressurizing, loading in a temperature controller and magnetizingReacting under the cooperation of a force stirrer; purging the reactor with hydrogen several times to remove air from the apparatus prior to the reaction; the reaction solvent is water; the initial pressure of hydrogen is 0.5-1.0 MPa; the reaction temperature is 160-180 ℃; the reaction time is 120-180 min;

(3) preparing cyclopentanone by taking furfural as a raw material: the reaction can also be carried out in a fixed bed reactor, and the specific operation is as follows: filling a catalyst into a constant temperature section in a fixed bed reactor, injecting furfural solution and hydrogen flow with certain concentration into the fixed bed reactor filled with the catalyst through a high-pressure metering pump, reacting to obtain a mixed material flow of cyclopentanone, water and hydrogen, and separating to obtain pure cyclopentanone.

Preferably, the metal-supported catalyst is PtCo/SiO₂The catalyst is a platinum-cobalt bimetallic catalyst synthesized by adopting a primary wet co-impregnation method, and the main active component of the catalyst is platinum and cobalt is taken as an auxiliary catalytic component; the mass ratio of the two metals is Pt to Co being 1:1, wherein the mass fraction of metal platinum is 1 wt%, the mass fraction of metal cobalt is 1 wt%, and the mass fraction of carrier SiO is₂The mass fraction is 98 percent; the precursor of the platinum is tetraamine platinum nitrate, and the precursor of the cobalt is cobalt nitrate hexahydrate.

Preferably, the catalyst obtained by the co-impregnation method needs to be loaded into a tubular furnace, and calcined and reduced for 2-4h at the temperature of 250-450 ℃ by introducing hydrogen gas for activation treatment.

Preferably, the following components: the hydrogenation rearrangement reaction of the furfural in the step (2) is carried out in a stainless steel high-pressure reaction kettle with a magnetic stirrer; typically, a magneton is placed in a polytetrafluoroethylene liner, and 50mg of PtCo/SiO are added₂Catalyst, 2mmol furfural and 4mL water; and (3) loading the reactor, pressurizing, and reacting under the cooperation of a temperature controller and a magnetic stirrer.

Preferably, after the reaction in the step (2) is finished, cooling, releasing pressure, opening the kettle, filtering and detecting.

Preferably, the reaction conditions in the step (2) are that the initial pressure of hydrogen is 1MPa, the reaction temperature is 180 ℃, and the reaction time is 3 h;

preferably, after the reaction in the step (2) is finished, putting the reaction kettle into ice water to be cooled to room temperature, and centrifugally separating the catalyst from the reaction solution; the product can be identified by GC-MS; simultaneously calculating the conversion rate of furfural and the yield of cyclopentanone by using gas chromatography analysis; in addition, the filtered catalyst powder is continuously washed by ethanol and can be recycled after being dried.

(1) Preparation of the high-quality platinum-based bimetallic supported catalyst: the active component and assistant of the catalyst are metal precursor salt solution, selected tetramine platinum nitrate and cobalt nitrate hexahydrate, and selected tetramine platinum nitrate Pt (NH)₄)₄(NO₃)₂5g of the platinum precursor solution is dissolved in 100mL of deionized water to prepare a platinum precursor solution Pt: 25.19mg/mL for use; taking cobalt nitrate hexahydrate Co (NO)₃)₂·6H₂Dissolving O2.4664 g in 50mL of deionized water to prepare a nickel precursor solution Co: 10mg/mL for standby;

(2) weighing SiO₂Uniformly spreading 490mg of carrier on a mortar, taking 200 mu L of platinum precursor solution, performing ultrasonic oscillation before taking, then adding 500 mu L of cobalt precursor solution and a proper amount of deionized water, performing ultrasonic oscillation for 5min to uniformly mix the solution, and uniformly dropwise adding the mixed solution to SiO₂Grinding the carrier until the catalyst is fully impregnated, and drying the carrier in a drying oven at 70 ℃ for 12 hours;

(3) taking out the impregnated and dried catalyst, grinding the impregnated and dried catalyst into uniform fine particles, and then putting the particles into a tube furnace, wherein quartz wool is arranged above and below a catalyst bed layer; under the condition that the flow rate of hydrogen flow is 30mL/min, the temperature is increased from room temperature to 400 ℃ at the temperature increase rate of 5 ℃/min, and the calcination reduction is carried out for 4h at 400 ℃; after the temperature is reduced to room temperature, nitrogen is exchanged to purge the pipeline, and the pipeline is taken out to obtain PtCo/SiO₂A catalyst;

(4) the hydrogenation rearrangement reaction of furfural is carried out in a stainless steel high-pressure reaction kettle equipped with a magnetic stirrer, and 50mg of PtCo/SiO₂Catalyst, 2mmol furfural and 4mL water; adding the mixture into a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining, and adding magnetons; after the reactor is filled, replacing the gas in the reactor with 2-3MPa hydrogen for three times to remove the air in the reactor; heating to a specified temperature of 160 ℃ by using an automatic temperature controller, then filling hydrogen to the pressure of 1MPa, and starting stirring to react; after the reaction is finished for 3 hours, the reaction kettle is placedCooling to room temperature in ice water, and centrifuging to separate catalyst and reaction liquid;

(5) sampling and analyzing, comparing the product qualitative by a gas chromatography-mass spectrometer GC-MS) with the gas chromatography retention time of a standard substance cyclopentanone, and determining that the main product is the cyclopentanone; quantitatively adopting a gas chromatography external standard method;

(6) the reaction for preparing cyclopentanone by furfural hydrogenation can also be carried out in a fixed bed reactor: specifically, 1.66mL of furfural serving as a raw material is dissolved in 40mL of ultrapure water, 0.58mL of dodecane serving as an internal standard substance is added, and a reaction solution is injected through a micro-injection pump; weighing PtCo/SiO₂500mg of the catalyst is filled in a constant temperature part in a quartz tube; introducing nitrogen into the reactor to replace gas for three times, then introducing nitrogen with the pressure of 1MPa, and keeping for a certain time for leak detection; introducing a reaction solution at a flow rate of 1mL/min to soak the catalyst, and changing the flow rate to 0.01mL/min after soaking completely; and introducing 20mL/min hydrogen into the reactor by using a gas flowmeter, mixing the hydrogen with the reaction liquid, allowing the furfural to pass through a catalyst bed layer, carrying out catalytic hydrogenation reaction for 9 hours at the reaction temperature of 180 ℃ and the reaction pressure of 1.0MPa, taking out the reaction liquid from a liquid storage tank every 3 hours, and analyzing the composition of the reaction liquid by using a Gas Chromatography (GC) to obtain a reaction result.

The method for converting furfural into cyclopentanone provided by the invention needs to consider the steps of catalytic hydrogenation, rearrangement and the like, so that catalyst systems with different functions, such as catalyst carriers, active components, auxiliary components and the like, need to be designed. The designed catalyst is a bimetallic supported catalyst. The carrier used by the catalyst is Al₂O₃、MgO、ZnO、SiO₂Activated carbon, multi-walled carbon nanotubes, and the like. The active component of the catalyst is Pt, and the auxiliary agent is one of Cr, Ni, Fe, Co and Cu. The mass ratio of the auxiliary agent load amount to the active component is 0.0-7.0: 1.

the invention provides the following technical scheme: a method for preparing cyclopentanone by high-selectivity hydrogenation with furfural as a raw material comprises the following steps:

(1) preparation of metal-supported catalyst: according to the proportion, dissolving a certain mass of metal salt (calculated based on the loading amount of the catalyst) in a proper amount of deionized water, and oscillating ultrasonic to uniformly disperse metal ions in the water; then, uniformly dropwise adding the obtained metal precursor mixed solution onto a carrier, grinding until the mixed solution is fully impregnated, and then putting the mixed solution into a drying oven at 60-90 ℃ for drying for 9-12 h; loading the dried catalyst into a tubular furnace, introducing hydrogen at the temperature of 250-450 ℃ for calcination and reduction for 2-4h, taking out the catalyst after cooling to obtain a supported platinum-based bimetallic catalyst, and then placing the catalyst into a drying box for storage;

(2) preparing cyclopentanone by taking furfural as a raw material: the hydrogenation rearrangement reaction of the furfural is carried out in a stainless steel high-pressure reaction kettle with a magnetic stirrer. Generally, reaction raw materials, a solvent and a catalyst are added into a reactor; loading into a kettle, pressurizing, and reacting under the cooperation of a temperature controller and a magnetic stirrer; purging the reactor with hydrogen several times to remove air from the apparatus prior to the reaction; 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, toluene; the initial pressure of hydrogen is 0.1-4 MPa; the reaction temperature is 100-220 ℃; the reaction time is 30-240 min; after the reaction is finished, cooling, releasing the pressure, opening the kettle, filtering and detecting;

a high-performance supported metal catalyst is prepared from Pt and another transition metal through co-immersion method and loading it on carrier. Wherein the active component of the catalyst is Pt, the transition metal is added to the platinum-based catalyst as an accelerant, and the transition metal is one of Cr, Ni, Fe, Co, Cu and the like. The precursors of the transition metals are all metal salt solutions thereof. For example: the platinum precursor salt may be Pt (NH)₄)₄(NO₃)₂、H₂PtCl₆、Na₂PtCl₄、Pt(NH₃)₂(NO₂)₂Or Pt (NH)₃)₄Cl₂Any one of the metal salts, the precursor of the cobalt is Co (NO)₃)₂·6H₂O、CoSO₄·7H₂O or CoCO₃Any one of the above. In addition, the mass ratio of the auxiliary agent loading amount to the active component is 0.0-7.0: 1.

comparison instituteThe carrier is Al₂O₃、MgO、ZnO、SiO₂Active carbon, MWNT represents multi-wall carbon nano-tube carrier treated by acid; the preferred support is SiO₂。

Comparing the reaction solvent of the step (2) with one or more of water, methanol, ethanol, isopropanol, methyl isobutyl ketone and toluene; preferably, the co-solvent is water.

In the step (2), the reaction condition is that the initial pressure of hydrogen is 0.1-4 MPa; the reaction temperature is 100-220 ℃; the reaction time is 30-240 min; more preferably, the reaction conditions are that the initial pressure of hydrogen is 1MPa, the reaction temperature is 180 ℃, the reaction time is 3h, and the solvent is water.

The principle of the invention is as follows:

has the advantages that:

the invention takes rich and cheap biomass derivative furfural as a raw material to prepare cyclopentanone by adopting a one-pot method, and has the advantages of simplified process, mild reaction conditions, reduced production cost, higher overall yield and high added value of hydrogenation products. The method provided by the invention is characterized in that the conversion of furfural into cyclopentanone is carried out in an aqueous medium. Water is a cheap and rich green solvent in the nature, and the water is used for replacing an organic solvent, so that the production cost is reduced, and the environment is protected. The active component of the supported metal catalyst provided by the invention has a high hydrogenation active center, stably exists in a water phase, and meanwhile, the carrier provides a weak Lewis acid center, and the PtCo bimetal and the carrier are mutually matched, so that the conversion rate of furfural and derivatives thereof and the selectivity of cyclopentanone compounds are favorably improved. In particular, PtCo/SiO in aqueous phase at 180 ℃ and 1MPa low hydrogen pressure₂The catalyst showed excellent activity, complete conversion of furfural occurred, and yield of cyclopentanone was 87%. Under similar conditions, the yield is superior to most of the catalysts reported so far. In addition, the raw material furfural and the product cyclopentanone are both carbon pentacompounds, have no carbon loss in the reaction process, and haveHigher atom economy. The conversion from furfural to cyclopentanone can be completed in one step in a reaction kettle, and can also be realized in a fixed bed reactor, and an intermediate product does not need to be separated, compared with the prior art, the method has the following obvious advantages: the preparation process is simple, no acid or alkaline auxiliary agent is needed to be added, the raw materials can be regenerated, the catalyst has high activity and stability, the reaction condition is milder, the energy consumption is reduced to a certain extent, the catalyst is more environment-friendly, and the energy problem facing the world at present can be partially relieved. Therefore, the invention has wide application potential in industrial production.

Drawings

FIG. 1 is a graph showing the evaluation of the catalytic performance of platinum-based catalysts of different active metals

FIG. 2 is a graph showing the evaluation of the catalytic performance of platinum-based catalysts on different supports

FIG. 3 is a graph showing the effect of cobalt loading on reactivity in a platinum-based bimetallic catalyst

FIG. 4 is a graph showing the effect of reaction temperature on product distribution

FIG. 5 is a graph showing the effect of reaction pressure on product distribution

FIG. 6 is a graph showing the effect of reaction solvent on product distribution

FIG. 7 is a graph showing the effect of mixed solvent on product distribution

FIG. 8 is a graph showing the effect of reaction time on product distribution

FIG. 9 shows the results of the catalyst stability test

FIG. 10 is an X-ray diffraction (XRD) pattern of a metal-supported platinum-based catalyst

FIG. 11 shows PtCo/SiO₂Element map of catalyst (HAADF-STEM)

FIG. 12 is a reaction scheme of preparing cyclopentanone from furfural

Detailed Description

The present invention will be described in further detail with reference to specific examples, which are provided for illustrative purposes only and are not intended to limit the scope of the present invention.

Example 1

(1) Preparation of platinum-based monometallic supported catalyst: catalyst and process for preparing sameThe active component of (A) can be a precursor salt solution of platinum metal, wherein we take the preferable tetraamineplatinum nitrate as an example, taking tetraamineplatinum nitrate (Pt (NH)₄)₄(NO₃)₂)5g was dissolved in 100mL of deionized water, and prepared as a platinum precursor solution (Pt: 25.19mg/mL) for use;

(2) weighing SiO₂Uniformly spreading 495mg of carrier on a mortar, taking 200 mu L of platinum precursor solution, performing ultrasonic oscillation before taking, then adding a proper amount of deionized water to enable the solution to just wet the carrier, performing ultrasonic oscillation for 5min, and uniformly dropwise adding the precursor solution of metal platinum to SiO₂Grinding the carrier until the catalyst is fully impregnated, and drying the carrier in a drying oven at 70 ℃ for 12 hours;

(3) taking out the impregnated and dried catalyst, grinding the impregnated and dried catalyst into uniform fine particles, putting the particles into a tubular furnace, and filling quartz wool above and below a catalyst bed layer. The solution is heated from room temperature to 400 ℃ at a heating rate of 5 ℃/min under a hydrogen flow (the flow rate is 30mL/min), and calcined and reduced for 4h at 400 ℃. After the temperature is reduced to room temperature, the nitrogen is exchanged to purge the pipeline, and the pipeline is taken out to obtain 1 wt% Pt/SiO₂A catalyst;

(4) the hydrogenation rearrangement reaction of the furfural is carried out in a stainless steel high-pressure reaction kettle with a magnetic stirrer. First, 50mg of PtCo/SiO₂Catalyst, 2mmol furfural, 4mL water. Adding into a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining, and adding magnetons. After the reactor is filled, the gas in the reactor is replaced by hydrogen with 2-3MPa for three times to remove the air in the reactor. Heating to a specified temperature of 160 ℃ by using an automatic temperature controller, then filling hydrogen to the pressure of 1MPa, and starting the reaction by opening the stirring. After the reaction is finished for 3 hours, the reaction kettle is placed into ice water to be rapidly cooled to room temperature, and then the catalyst and the reaction liquid are separated through centrifugation.

(5) Sampling and analyzing, and qualitatively comparing the products by using a gas chromatography-mass spectrometer (GC-MS) and the gas chromatography retention time of a standard substance (cyclopentanone), wherein the main product is the cyclopentanone. The quantification was performed by gas chromatography external standard method.

(6) The reaction for preparing cyclopentanone by furfural hydrogenation can also be carried out in a fixed bed reactor: dissolving 1.66mL of furfural serving as a raw material in 40mL of ultrapure water, and then adding0.58mL of internal standard substance dodecane is added, and the reaction solution is injected through a micro-injection pump. Weighing PtCo/SiO₂The catalyst 500mg was loaded into a quartz tube at a constant temperature. And introducing nitrogen into the reactor to replace the gas for three times, then introducing nitrogen with the pressure of 1MPa, and keeping the pressure for a certain time for leak detection. The reaction solution was introduced at a flow rate of 1mL/min to soak the catalyst, and after complete soaking, the flow rate was changed to 0.01 mL/min. And introducing 20mL/min of hydrogen into the reactor by using a gas flowmeter, mixing the hydrogen with the reaction liquid, allowing the furfural to pass through a catalyst bed layer, carrying out catalytic hydrogenation reaction for 9 hours at the reaction temperature of 160 ℃ and the reaction pressure of 1MPa, taking out the reaction liquid from a liquid storage tank every 3 hours, and analyzing the composition of the reaction liquid by using a Gas Chromatography (GC) to obtain a reaction result.

Example 2

(1) Preparation of platinum-based bimetallic supported catalyst: the active component and the auxiliary agent of the catalyst can be metal precursor salt solution thereof, wherein the preferable tetramine platinum nitrate and cobalt nitrate hexahydrate are taken as examples, and tetramine platinum nitrate (Pt (NH)₄)₄(NO₃)₂)5g was dissolved in 100mL of deionized water, and prepared as a platinum precursor solution (Pt: 25.19mg/mL) for use; cobalt nitrate hexahydrate (Co (NO)₃)₂·6H₂O)2.4664g was dissolved in 50mL of deionized water to prepare a nickel precursor solution Co: 10mg/mL for standby;

(3) taking out the impregnated and dried catalyst, grinding the impregnated and dried catalyst into uniform fine particles, putting the particles into a tubular furnace, and filling quartz wool above and below a catalyst bed layer. The solution is heated from room temperature to 400 ℃ at a heating rate of 5 ℃/min under a hydrogen flow (the flow rate is 30mL/min), and calcined and reduced for 4h at 400 ℃. After the temperature is reduced to room temperature, nitrogen is exchanged to purge the pipeline, and the pipeline is taken out to obtain PtCo/SiO₂A catalyst. The mass ratio of the two metals is Pt to Co which is 1 to 1, wherein the mass ratio of the platinum to the cobalt isThe mass fraction is 1 wt%, and the carrier SiO₂The mass fraction is 98%;

(4) the hydrogenation rearrangement reaction of the furfural is carried out in a stainless steel high-pressure reaction kettle with a magnetic stirrer. First, 50mg of PtCo/SiO₂Catalyst, 2mmol furfural, 4mL water. Adding into a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining, and adding magnetons. After the reactor is filled, the gas in the reactor is replaced by hydrogen with 2-3MPa for three times to remove the air in the reactor. Heating to a specified temperature of 160 ℃ by using an automatic temperature controller, then filling hydrogen to the pressure of 1MPa, and starting reaction by opening stirring. After the reaction is finished for 3 hours, the reaction kettle is placed into ice water to be rapidly cooled to room temperature, and then the catalyst and the reaction liquid are separated through centrifugation.

(6) The reaction for preparing cyclopentanone by furfural hydrogenation can also be carried out in a fixed bed reactor: dissolving 1.66mL of furfural serving as a raw material into 40mL of ultrapure water, adding 0.58mL of dodecane serving as an internal standard substance, and injecting a reaction solution through a micro-injection pump. Weighing PtCo/SiO₂The catalyst 500mg was loaded into a quartz tube at a constant temperature. And introducing nitrogen into the reactor to replace the gas for three times, then introducing nitrogen with the pressure of 1MPa, and keeping the pressure for a certain time for leak detection. The reaction solution was introduced at a flow rate of 1mL/min to soak the catalyst, and after complete soaking, the flow rate was changed to 0.01 mL/min. And introducing 20mL/min of hydrogen into the reactor by using a gas flowmeter, mixing the hydrogen with the reaction liquid, allowing the furfural to pass through a catalyst bed layer, carrying out catalytic hydrogenation reaction for 9 hours at the reaction temperature of 160 ℃ and the reaction pressure of 1MPa, taking out the reaction liquid from a liquid storage tank every 3 hours, and analyzing the composition of the reaction liquid by using a Gas Chromatography (GC) to obtain a reaction result.

Example 3

The influence of temperature on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 2 in that the reaction temperature in step (4) was 100 ℃ and the other procedures were the same as example 2.

Example 4

The influence of temperature on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 2 in that the reaction temperature in step (4) was 120 ℃ and the other procedures were the same as example 2.

Example 5

The influence of temperature on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 2 in that the reaction temperature in step (4) was 140 ℃ and the other procedures were the same as example 2.

Example 6

The influence of temperature on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 2 in that the reaction temperature in step (4) is 180 ℃, and the other procedures are the same as example 2.

Example 7

The influence of temperature on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 2 in that the reaction temperature in step (4) was 200 ℃ and the other procedures were the same as example 2.

Example 8

The influence of temperature on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 2 in that the reaction temperature in step (4) was 220 ℃ and the other procedures were the same as example 2.

Example 9

The influence of pressure on the preparation of cyclopentanone by furfural hydrogenation is explored:

(1) preparation of platinum-based bimetallic supported catalyst: the active component and the auxiliary agent of the catalyst can be metal precursor salt solution thereof, and the preferable tetraammine platinum nitrate and cobalt nitrate hexahydrate are taken as examples of tetraammine platinum nitrate (Pt (NH)₄)₄(NO₃)₂)5g was dissolved in 100mL of deionized water to prepare a platinum precursor solution (Pt: 25.19mg/mL) for use; cobalt nitrate hexahydrate (Co (NO)₃)₂·6H₂O)2.4664g was dissolved in 50mL of deionized water to prepare a nickel precursor solution Co: 10mg/mL for standby;

(2) weighing SiO₂Uniformly spreading 490mg of carrier on a mortar, taking 200 μ L of platinum precursor solution, performing ultrasonic vibration before taking, and then adding 500 μ L of cobalt precursor solution and appropriate amount of cobalt precursor solutionDeionized water, performing ultrasonic treatment for 5min to mix uniformly, and dripping the mixed solution into SiO₂Grinding the carrier until the catalyst is fully impregnated, and drying the carrier in a drying oven at 70 ℃ for 12 hours;

(3) taking out the impregnated and dried catalyst, grinding the impregnated and dried catalyst into uniform fine particles, putting the particles into a tubular furnace, and filling quartz wool above and below a catalyst bed layer. The solution is heated from room temperature to 400 ℃ at a heating rate of 5 ℃/min under a hydrogen flow (the flow rate is 30mL/min), and calcined and reduced for 4h at 400 ℃. After the temperature is reduced to room temperature, nitrogen is exchanged to purge the pipeline, and the pipeline is taken out to obtain PtCo/SiO₂A catalyst;

(4) the hydrogenation rearrangement reaction of the furfural is carried out in a stainless steel high-pressure reaction kettle with a magnetic stirrer. First, 50mg of PtCo/SiO₂Catalyst, 2mmol furfural, 4mL water. Adding into a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining, and adding magnetons. After the reactor is filled, the gas in the reactor is replaced by hydrogen with 2-3MPa for three times to remove the air in the reactor. Heating to a specified temperature of 180 ℃ by using an automatic temperature controller, then filling hydrogen to the pressure of 0.1MPa, and starting the reaction by opening the stirring. After the reaction is finished for 3 hours, the reaction kettle is placed into ice water to be rapidly cooled to room temperature, and then the catalyst and the reaction liquid are separated through centrifugation.

(6) The reaction for preparing cyclopentanone by furfural hydrogenation can also be carried out in a fixed bed reactor: dissolving 1.66mL of furfural serving as a raw material into 40mL of ultrapure water, adding 0.58mL of dodecane serving as an internal standard substance, and injecting a reaction solution through a micro-injection pump. Weighing PtCo/SiO₂The catalyst 500mg was loaded into a quartz tube at a constant temperature. And introducing nitrogen into the reactor to replace the gas for three times, then introducing nitrogen with the pressure of 1MPa, and keeping the pressure for a certain time for leak detection. The reaction solution was introduced at a flow rate of 1mL/min to soak the catalyst, and after complete soaking, the flow rate was changed to 0.01 mL/min. Then introducing hydrogen gas into the reactor by a gas flow meter for 20mL/min, mixing the hydrogen gas with the reaction liquid, and allowing the mixture to pass through a catalyst bed layer to perform catalytic hydrogenation reaction on the furfural,the reaction time is 9h, the reaction temperature is 180 ℃, the reaction pressure is 0.1MPa, the reaction liquid is taken out from the liquid storage tank every 3h, and the composition of the reaction liquid is analyzed by a gas chromatography GC, so that the reaction result is obtained.

Example 10

The influence of pressure on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 9 in that the reaction pressure in step (4) was 0.5MPa, and the other procedures were the same as example 9.

Example 11

The influence of pressure on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 9 in that the reaction pressure in step (4) was 1.0MPa, and the other procedures were the same as example 9.

Example 12

The influence of pressure on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 9 in that the reaction pressure in step (4) was 2.0MPa, and the other procedures were the same as example 9.

Example 13

The influence of pressure on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 9 in that the reaction pressure in step (4) was 3.0MPa, and the other procedures were the same as example 9.

Example 14

The influence of pressure on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 9 in that the reaction pressure in step (4) was 4.0MPa, and the other procedures were the same as example 9.

Example 15

The influence of a reaction solvent on the preparation of cyclopentanone by furfural hydrogenation is explored:

(1) preparation of platinum-based bimetallic supported catalyst: the active component and the auxiliary agent of the catalyst can be metal precursor salt solution thereof, wherein the preferable tetramine platinum nitrate and cobalt nitrate hexahydrate are taken as examples, and tetramine platinum nitrate (Pt (NH)₄)₄(NO₃)₂)5g was dissolved in 100mL of deionized water, and prepared as a platinum precursor solution (Pt: 25.19mg/mL) for use; cobalt nitrate hexahydrate (Co (NO)₃)₂·6H₂O)2.4664g is dissolved in 50mL of deionized water to prepareNickel precursor solution Co: 10mg/mL for standby;

(4) the hydrogenation rearrangement reaction of the furfural is carried out in a stainless steel high-pressure reaction kettle with a magnetic stirrer. First, 50mg of PtCo/SiO₂Catalyst, 2mmol furfural and 4mL water are added into a stainless steel high-pressure reaction kettle with polytetrafluoroethylene lining, and magnetons are added. After the reactor is filled, the gas in the reactor is replaced by hydrogen with 2-3MPa for three times to remove the air in the reactor. Heating to a specified temperature of 180 ℃ by using an automatic temperature controller, then filling hydrogen to the pressure of 1MPa, and starting the reaction by opening the stirring. After the reaction is finished for 3 hours, the reaction kettle is placed into ice water to be rapidly cooled to room temperature, and then the catalyst and the reaction liquid are separated through centrifugation.

(6) The reaction for preparing cyclopentanone by furfural hydrogenation can also be carried out in a fixed bed reactor: dissolving 1.66mL of furfural serving as a raw material into 40mL of ultrapure water, adding 0.58mL of dodecane serving as an internal standard substance, and injecting a reaction solution through a micro-injection pump. Weighing PtCo/SiO₂The catalyst 500mg was loaded into a quartz tube at a constant temperature. The reactor is firstly filled with nitrogen to replace gas for three times, then the nitrogen with the pressure of 1MPa is filled, and the nitrogen is kept for a certain timeAnd detecting leakage. The reaction solution was introduced at a flow rate of 1mL/min to soak the catalyst, and after complete soaking, the flow rate was changed to 0.01 mL/min. And then introducing 20mL/min of hydrogen into the reactor through a gas flow meter, mixing the hydrogen with the reaction liquid, allowing the furfural to pass through a catalyst bed layer, performing catalytic hydrogenation reaction for 9 hours at the reaction temperature of 180 ℃ under the reaction pressure of 1MPa, taking out the reaction liquid from the liquid storage tank every 3 hours, and analyzing the composition of the reaction liquid by Gas Chromatography (GC) to obtain a reaction result.

Example 16

The influence of a reaction solvent on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 15 in the solvent methyl isobutyl ketone for the reaction in step (4), and the other procedures are the same as example 15.

Example 17

The influence of a reaction solvent on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 15 in the solvent toluene for the reaction in step (4), and the other procedures are the same as example 15.

Example 18

The influence of a reaction solvent on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 15 in the reaction solvent methanol in step (4), and the other procedures are the same as example 15.

Example 19

The influence of a reaction solvent on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 15 in the solvent ethanol for the reaction in step (4), and the other procedures are the same as example 15.

Example 20

The influence of a reaction solvent on the preparation of cyclopentanone by furfural hydrogenation is explored: this example is different from example 15 in that isopropanol was used as a reaction solvent in the step (4), and the other procedures were the same as example 15.

Example 21

Catalyst stability experiment: the procedure of this example is the same as example 15, but the catalyst is recovered by repeated washing with ethanol after the first reaction, and drying. The yield of cyclopentanone obtained by the second reuse is 85%.

Example 22

Catalyst stability experiment: the procedure of this example is the same as example 15, but the catalyst is recovered by repeated washing with ethanol after the second reaction, and drying. The yield of cyclopentanone obtained by recycling the first time for 3 times is 86%.

Example 23

Catalyst stability experiment: the procedure of this example is the same as example 15, but the catalyst is recovered by repeated washing with ethanol after the third reaction. The yield of cyclopentanone obtained by the 4 th recycling was 84%.

Example 24

Catalyst stability experiment: the procedure of this example is the same as example 15, but the catalyst is recovered by washing with ethanol repeatedly after the fourth reaction. The yield of cyclopentanone obtained in the 5 th application was 78%.

Comparative example 1

(1) Influence of catalyst Components: the auxiliary component Co in the embodiment 2 is changed into any one of transition metals such as Ni, Fe, Cu, Cr and the like, and SiO is used₂As a carrier, PtNi/SiO can be obtained₂，PtFe/SiO₂，PtCu/SiO₂，PtCr/SiO₂And the like. The active component and the auxiliary agent of the catalyst are metal precursor salt solutions thereof, and the preferable tetramine platinum nitrate and nickel nitrate hexahydrate are taken as examples, namely tetramine platinum nitrate (Pt (NH)₄)₄(NO₃)₂)5g was dissolved in 100mL of deionized water to prepare a platinum precursor solution (Pt: 25.19mg/mL) for use; taking nickel nitrate hexahydrate (Ni (NO)₃)₂·6H₂O)2.4774g was dissolved in 50mL of deionized water to prepare a Ni precursor solution Ni: 10mg/mL for use.

(2) Weighing SiO₂Uniformly spreading 490mg of carrier on a mortar, taking 200 mu L of platinum precursor solution, performing oscillation ultrasonic treatment before taking, then adding 500 mu L of cobalt precursor solution and a proper amount of deionized water, performing ultrasonic treatment for 5min to uniformly mix the solution, and uniformly dropwise adding the mixed solution to SiO₂Grinding the carrier until the catalyst is fully impregnated, and drying the carrier in a drying oven at 70 ℃ for 12 hours;

(3) taking out the impregnated and dried catalyst, grinding the impregnated and dried catalyst into uniform fine particles, putting the particles into a tubular furnace, and placing the particles on a catalyst bed layerThe lower part is filled with quartz cotton. The solution is heated from room temperature to 400 ℃ at a heating rate of 5 ℃/min under a hydrogen flow (the flow rate is 30mL/min), and calcined and reduced for 4h at 400 ℃. Cooling to room temperature, changing nitrogen to purge the pipeline, and taking out to obtain PtNi/SiO₂A catalyst;

(4) the hydrogenation rearrangement reaction of the furfural is carried out in a stainless steel high-pressure reaction kettle with a magnetic stirrer. First, 50mg of PtNi/SiO₂Catalyst, 2mmol furfural, 4mL water. Adding into a stainless steel high-pressure reaction kettle with polytetrafluoroethylene lining, and adding magnetons. After the reactor is filled, the gas in the reactor is replaced by hydrogen with 2-3MPa for three times to remove the air in the reactor. Heating to a specified temperature of 160 ℃ by using an automatic temperature controller, then filling hydrogen to the pressure of 1MPa, and starting the reaction by opening the stirring. After the reaction is finished for 3 hours, the reaction kettle is placed into ice water to be rapidly cooled to room temperature, and then the catalyst and the reaction liquid are separated through centrifugation.

(5) Sampling and analyzing, comparing products qualitatively by using GC-MS and gas chromatography retention time of a standard substance (cyclopentanone), and qualitatively determining that a main product is the cyclopentanone. The quantification was performed by gas chromatography external standard method.

(6) The reaction for preparing cyclopentanone by furfural hydrogenation can also be carried out in a fixed bed reactor: dissolving 1.66mL of furfural serving as a raw material into 40mL of ultrapure water, adding 0.58mL of dodecane serving as an internal standard substance, and injecting a reaction solution through a micro-injection pump. Weighing PtNi/SiO₂The catalyst 500mg was loaded into a quartz tube at a constant temperature. And introducing nitrogen into the reactor to replace the gas for three times, then introducing the nitrogen with the pressure of 1MPa, and keeping for a certain time for leak detection. The reaction solution was introduced at a flow rate of 1mL/min to soak the catalyst, and after complete soaking, the flow rate was changed to 0.01 mL/min. And introducing 20mL/min of hydrogen into the reactor by using a gas flowmeter, mixing the hydrogen with the reaction liquid, allowing the furfural to pass through a catalyst bed layer, carrying out catalytic hydrogenation reaction for 9 hours at the reaction temperature of 160 ℃ and the reaction pressure of 1MPa, taking out the reaction liquid from a liquid storage tank every 3 hours, and analyzing the composition of the reaction liquid by using a Gas Chromatography (GC) to obtain a reaction result.

(7) The performance results of cyclopentanone prepared by furfural hydrogenation with different catalyst components are shown in figure 1

Comparative example 2

(1)Co/SiO₂Preparation of the catalyst: here we take the preferred cobalt nitrate hexahydrate as an example, taking cobalt nitrate hexahydrate (Co (NO)₃)₂·6H₂O)2.4664g was dissolved in 50mL of deionized water to prepare a nickel precursor solution Co: 10mg/mL for standby;

(2) weighing SiO₂Uniformly spreading 495mg of carrier on a mortar, taking 200 mu L of cobalt precursor solution, performing oscillation ultrasonic treatment before taking, then adding a proper amount of deionized water to ensure that the deionized water can just wet the carrier, performing ultrasonic treatment for 5min, and uniformly dripping the precursor solution of metal cobalt into SiO₂Grinding the carrier until the catalyst is fully impregnated, and drying the carrier in a drying oven at 70 ℃ for 12 hours;

(3) taking out the impregnated and dried catalyst, grinding the impregnated and dried catalyst into uniform fine particles, and then putting the particles into a tubular furnace, wherein quartz cotton is filled above and below a catalyst bed layer. The solution is heated from room temperature to 400 ℃ at a heating rate of 5 ℃/min under a hydrogen flow (the flow rate is 30mL/min), and calcined and reduced for 4h at 400 ℃. After the temperature is reduced to room temperature, the nitrogen is exchanged to purge the pipeline, and the pipeline is taken out to obtain 1 wt% Co/SiO₂A catalyst;

(4) the hydrogenation rearrangement reaction of the furfural is carried out in a stainless steel high-pressure reaction kettle with a magnetic stirrer. First, 50mg of Co/SiO₂Catalyst, 2mmol furfural, 4mL water. Adding into a stainless steel high-pressure reaction kettle with polytetrafluoroethylene lining, and adding magnetons. After the reactor is filled, the gas in the reactor is replaced by hydrogen with 2-3MPa for three times to remove the air in the reactor. Heating to a specified temperature of 160 ℃ by using an automatic temperature controller, then filling hydrogen to the pressure of 1MPa, and starting the reaction by opening the stirring. After the reaction is finished for 3 hours, the reaction kettle is placed into ice water to be rapidly cooled to room temperature, and then the catalyst and the reaction liquid are separated through centrifugation.

(6) The reaction for preparing cyclopentanone by furfural hydrogenation can also be carried out in a fixed bed reactor: dissolving 1.66mL of furfural serving as a raw material into 40mL of ultrapure water, adding 0.58mL of dodecane serving as an internal standard substance, and introducing a reaction solutionAnd introducing sample by a trace sample introduction pump. Weighing Co/SiO₂Catalyst 500mg was loaded into a quartz tube at a constant temperature. And introducing nitrogen into the reactor to replace the gas for three times, then introducing nitrogen with the pressure of 1MPa, and keeping the pressure for a certain time for leak detection. The reaction solution was introduced at a flow rate of 1mL/min to soak the catalyst, and after complete soaking, the flow rate was changed to 0.01 mL/min. And introducing 20mL/min of hydrogen into the reactor by using a gas flowmeter, mixing the hydrogen with the reaction liquid, allowing the furfural to pass through a catalyst bed layer, carrying out catalytic hydrogenation reaction for 9 hours at the reaction temperature of 160 ℃ and the reaction pressure of 1MPa, taking out the reaction liquid from a liquid storage tank every 3 hours, and analyzing the composition of the reaction liquid by using a Gas Chromatography (GC) to obtain a reaction result.

Comparative example 3

Influence of the vector: the carrier in example 2 was changed to Al₂O₃MgO, ZnO, activated carbon and multi-walled carbon nanotube MWNT to obtain PtCo/Al₂O₃PtCo/MgO, PtCo/ZnO, PtCo/Ac and PtCo/MWNT. Otherwise, the same procedure as in example 2 was repeated. The performance reaction results of the hydrogenation of furfural on different supports to prepare cyclopentanone are shown in FIG. 2

Comparative example 4

Effect of loading of promoter metal Co: the percentage content of the Co additive component in example 2 was changed to 0, 0.3, 0.5, 0.7, 1.0, 3.0, 5.0, 7.0. With preferential SiO₂As a carrier, Pt/SiO can be obtained₂，PtCo_0.3/SiO₂，PtCo_0.7/SiO₂，PtCo/SiO₂，PtCo₃/SiO₂，PtCo₅/SiO₂，PtCo₇/SiO₂. The rest of the procedure was the same as in example 2. The reaction results of the metal Co loading on the furfural hydrogenation performance to prepare cyclopentanone are shown in FIG. 3

Comparative example 5

Effect of reaction time on product distribution:

the difference of this comparative example is that the reaction time in step (4) of example 15 was changed to 30min, 60min, 90min, 120min, 150min, 180min, 210min, and 240 min. The rest was the same as in example 15. The reaction results are shown in FIG. 8

Comparative example 6

The experiment of preparing cyclopentanone by furfural hydrogenation was carried out by mixing ethanol and water in different proportions as solvents. The total volume of the solution is ensured to be unchanged, and the proportion of ethanol to water is respectively as follows: 100:0,75:25, 50:50, 25:75, 0: 100; the results of the reaction are shown in FIG. 7, demonstrating that the solvent water is critical for cyclopentanone production.

According to the experimental results of FIG. 1, in SiO₂As the preferred support, the introduction of the co-agent component cobalt on the platinum monometallic catalyst can greatly improve the selectivity of cyclopentanone. Wherein in PtCo/SiO₂The conversion rate of furfural on the catalyst was 97%, and the selectivity of cyclopentanone was 86%;

from fig. 2, we examined the effect of PtCo bimetallic loading on different supports on reactivity. The surface of the carrier has abundant acid/alkali active sites, and the acid/alkali active site ratio has certain influence on the reaction selectivity. Firstly, selecting a plurality of representative carriers according to the acid-base property of the carriers; e.g. the acidic or weakly acidic oxides AC, MWNT, SiO₂(ii) a Basic oxides ZnO, MgO; and amphoteric oxide Al₂O₃，Nb₂O₅. According to the reaction result, the weakly acidic carrier is beneficial to preparing cyclopentanone by furfural hydrogenation.

According to FIG. 3, we further examined the effect of metal loading on catalytic activity, and the reaction results show that PtCo/SiO₂Bimetallic catalysts show the best catalytic activity; further increasing the content of the additive cobalt may cause aggregation of metal particles on the carrier, which is not favorable for preparing cyclopentanone by furfural hydrogenation;

according to fig. 4, the effect of reaction temperature on product distribution is shown. At low temperatures (<120 ℃), the reaction produces mainly furfuryl alcohol. As the temperature increased, cyclopentanone yield increased and was highest at 180 ℃. Further increasing the reaction temperature to excessively hydrogenate the cyclopentanone into cyclopentanol;

from the results of fig. 5, the effect of reaction pressure on product distribution is shown. As the pressure increases (0-1MPa), cyclopentanone selectivity increases and reaches a maximum at 1 MPa. Further increasing the reaction pressure (>1MPa) and excessively hydrogenating cyclopentanone into cyclopentanol;

fig. 6 and 7 show that the choice of solvent is critical for the furfural liquid phase hydrogenation reaction. Especially, the solvent water plays a crucial role in the process of preparing cyclopentanone by furfural hydrogenation rearrangement.

Fig. 8 shows the effect of reaction time on product distribution, with the yield of cyclopentanone gradually increasing to a maximum as the reaction time increases from 30min to 3 h. The reaction time is further prolonged to 240min, and the cyclopentanone is partially hydrogenated to cyclopentanol.

According to the reaction result of the catalyst recycling in fig. 9, after 5 times of continuous operation, the conversion rate of furfural is slightly reduced from 100% to 97%, and the yield of cyclopentanone is still 78%. This is due to the fact that during the recovery process, a certain amount of cobalt is lost by the filtration through washing, resulting in a slight decrease in the reactivity; the ICP results before and after the catalyst reaction are given in the following table:

TABLE 1 Metal content of fresh catalyst and 5 catalysts used

Sample (I)	Percent Pt (wt.%)	Percent Co (wt.%)
			PtCo/SiO₂	1.13	1.05
5th-PtCo/SiO₂	1.04	0.54

FIG. 10XRD patterns of Pt monometallic and bimetallic catalystsThe crystal structure is characterized. In Pt/SiO₂The XRD pattern of the catalyst observed that there were distinct diffraction peaks at 39 °, 46 ° and 67 °, corresponding to the (111), (200) and (220) crystal plane structures of Pt, respectively. In contrast, in PtCo/SiO₂No obvious Pt phase peak is found in an XRD spectrum of the bimetallic catalyst, which shows that the introduction of metal cobalt is beneficial to the dispersion of metal platinum;

FIG. 11 analysis of PtCo/SiO by HAADF-STEM₂The nanostructure and the elemental distribution of the catalyst. We can clearly see that the platinum-cobalt bimetallic nanoparticles are uniformly dispersed on the support. This is consistent with XRD results;

according to the reaction result and the related characteristics, the reaction for preparing cyclopentanone by hydrogenation rearrangement of furfural under the catalysis of platinum-cobalt bimetallic catalysis on six common carriers is researched under mild reaction conditions. A simple and well-repeatable method is developed to support metal loading on AC, MWNT, SiO₂，Al₂O₃ZnO, MgO. Through the optimization of reaction conditions, the optimized PtCo/SiO₂On the catalyst, under the condition of 1MPa low hydrogen pressure and 180 ℃, the furfural can be completely converted in the water phase. The conversion rate of furfural is 100%, and the selectivity of cyclopentanone is as high as 89%. In the current catalytic system, PtCo/SiO₂Surface synergy between the acidic centers on the catalyst and the metal species greatly promotes rearrangement of furfural intermediates, resulting in high yields of the target cyclopentanone product. These findings provide a high performance metal supported catalyst for the conversion of furfural to cyclopentanone in the aqueous phase. The metal-loaded heterogeneous catalyst which is easy to obtain, efficient and stable has wide industrial application prospect. Compared with the traditional process production route, the process route disclosed by the invention is simple in preparation process, does not need to add acid or alkaline auxiliaries, is renewable in raw materials, is milder in reaction conditions, reduces energy consumption to a certain extent, is more environment-friendly, and can partially relieve the global energy problem.

In the method for preparing cyclopentanone, the reaction can also be carried out in a fixed bed reactor, and the specific operation is as follows: filling a catalyst into a constant temperature section in a fixed bed reactor, injecting furfural solution and hydrogen flow with certain concentration into the fixed bed reactor filled with the catalyst through a high-pressure metering pump, reacting to obtain a mixed material flow of cyclopentanone, water and hydrogen, and separating to obtain pure cyclopentanone.

The invention is not limited to the specific technical solutions described in the above embodiments, and all technical solutions formed by equivalent substitutions are within the scope of the claims of the invention.

Claims

1. A method for preparing cyclopentanone by high-selectivity hydrogenation with furfural as a raw material is characterized by comprising the following steps: the method comprises the following steps:

(1) metal supported catalyst PtCo/SiO₂The preparation of (1): PtCo/SiO is synthesized by adopting an incipient wetness co-impregnation method₂The catalyst comprises a main active component of platinum and a co-catalyst component of cobalt; the mass ratio of the two metals is Pt to Co being 1:1, wherein the mass fraction of metal platinum is 1 wt%, the mass fraction of metal cobalt is 1 wt%, and the mass fraction of carrier SiO is₂The mass fraction is 98 percent; the preparation method comprises the steps of dissolving a certain mass of metal salt in a proper amount of deionized water based on the load calculation of a catalyst, and oscillating ultrasonic to uniformly disperse metal ions in water; then, the obtained metal precursor mixed solution is uniformly dripped into SiO₂Grinding the carrier until the carrier is fully soaked, and then putting the carrier into a drying oven at 60-90 ℃ for drying for 9-12 h; the dried catalyst is loaded into a tubular furnace, hydrogen is introduced for calcination and reduction for 2 to 4 hours at the temperature of 250-450 ℃, and the catalyst is taken out after cooling to obtain the metal-loaded PtCo/SiO₂The catalyst is put into a drying cabinet for storage;

(2) preparing cyclopentanone by taking furfural as a raw material: the hydrogenation rearrangement reaction of furfural is carried out in a stainless steel high-pressure reaction kettle with a magnetic stirrer, and reaction raw materials of furfural, solvent water and catalyst metal-loaded PtCo/SiO are added into the reactor₂(ii) a Loading into a kettle, pressurizing, and reacting under the cooperation of a temperature controller and a magnetic stirrer; purging the reactor with hydrogen several times to remove air from the apparatus prior to the reaction; the reaction solvent is water; the initial pressure of hydrogen is 0.5-1.0 MPa; the reaction temperature is 160 ℃ and 180 DEG C(ii) a The reaction time is 120-180 min;

2. The method for preparing cyclopentanone by highly selective hydrogenation according to claim 1, wherein the method comprises the following steps: the metal-loaded catalyst is PtCo/SiO₂The catalyst is a platinum-cobalt bimetallic catalyst synthesized by adopting a primary wet co-impregnation method, and the main active component of the catalyst is platinum and cobalt is taken as an auxiliary catalytic component; the mass ratio of the two metals is Pt to Co being 1:1, wherein the mass fraction of metal platinum is 1 wt%, the mass fraction of metal cobalt is 1 wt%, and the mass fraction of carrier SiO is₂The mass fraction is 98 percent; the precursor of the platinum is tetraamine platinum nitrate, and the precursor of the cobalt is cobalt nitrate hexahydrate.

3. The method for preparing cyclopentanone by highly selective hydrogenation according to claim 1, wherein the method comprises the following steps: the catalyst obtained by the co-impregnation method needs to be loaded into a tubular furnace, and is calcined and reduced for 2-4h by introducing hydrogen at the temperature of 250-450 ℃ for activation treatment.

4. The method for preparing cyclopentanone by highly selective hydrogenation according to claim 1, wherein the method comprises the following steps: the hydrogenation rearrangement reaction of the furfural in the step (2) is carried out in a stainless steel high-pressure reaction kettle with a magnetic stirrer; typically, a magneton is placed in a polytetrafluoroethylene liner, and 50mg of PtCo/SiO are added₂Catalyst, 2mmol furfural and 4mL water; and (3) loading the reactor, pressurizing, and reacting under the cooperation of a temperature controller and a magnetic stirrer.

5. The method for preparing cyclopentanone by highly selective hydrogenation according to claim 1, wherein the method comprises the following steps: and (3) after the reaction in the step (2) is finished, cooling, releasing pressure, opening the kettle, filtering and detecting.

6. The method for preparing cyclopentanone by highly selective hydrogenation according to claim 1, wherein the method comprises the following steps: in the step (2), the reaction conditions are that the initial pressure of hydrogen is 1MPa, the reaction temperature is 180 ℃ and the reaction time is 3 h.

7. The method for preparing cyclopentanone by highly selective hydrogenation according to claim 1, wherein the method comprises the following steps: after the reaction is finished in the step (2), putting the reaction kettle into ice water, cooling to room temperature, and centrifugally separating the catalyst from the reaction liquid; the product can be identified by a gas chromatography-mass spectrometer GC-MS; simultaneously calculating the conversion rate of furfural and the yield of cyclopentanone by using gas chromatography analysis; in addition, the filtered catalyst powder is continuously washed by ethanol and can be recycled after being dried.

8. The method for preparing cyclopentanone by highly selective hydrogenation according to claim 1, wherein the method comprises the following steps:

(1) preparation of platinum-based bimetallic supported catalyst: the active component and assistant of the catalyst are metal precursor salt solution, selected tetramine platinum nitrate and cobalt nitrate hexahydrate, and selected tetramine platinum nitrate Pt (NH)₄)₄(NO₃)₂5g of the platinum precursor solution is dissolved in 100mL of deionized water to prepare a platinum precursor solution Pt: 25.19mg/mL for use; taking cobalt nitrate hexahydrate Co (NO)₃)₂·6H₂Dissolving O2.4664 g in 50mL of deionized water to prepare a nickel precursor solution Co: 10mg/mL for standby;

(3) taking out the impregnated and dried catalyst and grinding the impregnated and dried catalyst into uniform fine particlesLoading the granules into a tube furnace, and loading quartz wool on the upper part and the lower part of a catalyst bed layer; under the condition that the flow rate of hydrogen flow is 30mL/min, the temperature is increased from room temperature to 400 ℃ at the temperature increase rate of 5 ℃/min, and the calcination reduction is carried out for 4h at 400 ℃; after the temperature is reduced to room temperature, nitrogen is exchanged to purge the pipeline, and the pipeline is taken out to obtain PtCo/SiO₂A catalyst;

(4) the hydrogenation rearrangement reaction of furfural is carried out in a stainless steel high-pressure reaction kettle equipped with a magnetic stirrer, and 50mg of PtCo/SiO₂Catalyst, 2mmol furfural and 4mL water; adding the mixture into a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining, and adding magnetons; after the reactor is filled, replacing the gas in the reactor with 2-3MPa hydrogen for three times to remove the air in the reactor; heating to a specified temperature of 160 ℃ by using an automatic temperature controller, then filling hydrogen to the pressure of 1MPa, and starting stirring to react; after the reaction is finished for 3 hours, the reaction kettle is placed into ice water to be rapidly cooled to room temperature, and then the catalyst and the reaction liquid are separated through centrifugation;