A montmorillonite-based furfural hydrogenation catalyst and a preparation method thereof

Abstract

The present application relates to a kind of montmorillonite-based furfural hydrogenation catalyst and its preparation method, and it is related to biomass conversion technical field.The catalyst of the present application uses montmorillonite as carrier, and platinum nanoparticle is active component, can significantly improve the conversion rate of furfural hydrogenation and furfuryl alcohol selectivity;At the same time, the preparation method of the catalyst of the present application has mild reaction condition, improves the conversion rate of furfural hydrogenation and furfuryl alcohol selectivity, and also significantly reduces production cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomass conversion, in particular to a montmorillonite-based furfural hydrogenation catalyst and a preparation method thereof. BACKGROUND

[0002] Furfuryl alcohol is an important biomass chemical intermediate, which is used to produce many chemical products, such as vitamin C, lysine, plasticizer, dispersant, lubricant and resin, etc. Due to the importance of furfuryl alcohol in chemical industry and the renewable utilization of furfural, the research on selective hydrogenation of furfural to furfuryl alcohol has attracted widespread attention.

[0003] Noble metal nanoparticles have been proved to be effective catalysts in hydrogenation reactions, which have been widely used in industry. Among various noble metal nanoparticles, platinum nanoparticles are widely used in catalytic hydrogenation reactions due to the unique electrical and chemical properties of platinum catalysts. Similarly, platinum-based catalysts also exhibit excellent catalytic activity in furfural hydrogenation reactions.

[0004] Due to the environmental friendliness, low cost and abundant reserves of clay minerals, they have been proved to have broad application scenarios. Among them, montmorillonite has an ordered layered structure, unique swelling property and high ion exchange property, and is an excellent carrier candidate.

[0005] Due to the possible hydrogenolysis and decarboxylation of C=O bond, or the hydrogenation of C=O bond and furan ring, it is difficult to control the selectivity of the product. Furfural catalytic hydrogenation to furfuryl alcohol is usually carried out in gas phase or liquid phase. Compared with liquid phase hydrogenation process, furfural gas phase hydrogenation process has more by-products, and needs to vaporize furfural, which has high energy consumption. Therefore, it is of great significance to explore efficient catalytic system for furfural liquid phase hydrogenation to furfuryl alcohol.

[0006] Copper-chromium catalyst is the most widely used catalyst in furfural hydrogenation industry in the past few decades. However, the strict reaction conditions such as high temperature and high pressure greatly increase the production cost, and the high toxicity of copper-chromium catalyst has a serious impact on the environment, which does not meet the requirements of sustainable development.

[0007] A Chinese patent with publication number CN112791731A introduces a catalyst for the gas-phase hydrogenation of furfural to furfuryl alcohol, as well as a preparation method and application thereof. The catalyst is composed of sepiolite and active components supported on the sepiolite, the active components being CuO, Cr2O3 and CeO2; wherein the molar ratio of CuO to Cr2O3 and CeO2 is 1:0.33-0.5:0.008-0.020, and the content of sepiolite is 20-80 wt% based on the total weight of the catalyst. The catalyst has excellent catalytic activity in the gas-phase hydrogenation of furfural, but due to the presence of heavy metal ions such as copper and chromium, and the high content of CuO and Cr2O3, the catalyst has high toxicity and can have a serious impact on the environment. At the same time, the high reaction temperature results in high costs. A Chinese patent with publication number CN106083775A introduces a green synthesis route for furfuryl alcohol. The synthesis route uses porous nanometer silicon carbide supported platinum catalyst to catalyze the selective hydrogenation of furfural in water solvent at room temperature, to synthesize furfuryl alcohol with high selectivity. The catalyst is prepared by ultrasonic immersion, drying, and then reduction at 500°C in 99.999% high-purity hydrogen, with the weight ratio of Pt active metal in the catalyst being 1-5%, the hydrogen pressure being 0.5-2 MPa, the reaction temperature being 25°C, and the reaction time being 30-240 min. The conversion rate of furfural can reach 99%, and the selectivity of furfuryl alcohol can reach 98%. However, the preparation cost of the catalyst is high. A Chinese patent with publication number CN115160266A introduces a method for using carbon nanotube inner wall supported platinum nanoparticle catalyst for furfural hydrogenation reaction. Through external force stirring and grinding, the catalyst interacts with the open surface of the carbon nanotube, and during the slow evaporation of the solvent, the filled metal precursor continuously enters the lumen of the carbon tube. By grinding and controlling the slow drying, there is enough time for more platinum ions to enter the lumen of the carbon tube. Under normal temperature and pressure, using isopropyl alcohol as the solvent, 5 wt% Pt MWNT catalyst in a reaction solution with a furfural mass concentration of 5 wt%, after 100 h of reaction, the conversion rate of furfural can still reach 90%, and the selectivity of furfuryl alcohol can still reach 95%. However, concentrated nitric acid is used in the preparation process of carbon nanotubes, and the preparation process is complex, greatly increasing the preparation cost of the catalyst. SUMMARY

[0008] The purpose of the present application is to provide a montmorillonite-based furfural hydrogenation catalyst and a preparation method thereof, to solve the problems existing in the prior art, and to prepare a catalyst with excellent selective hydrogenation effect of furfural at low cost, so as to realize efficient conversion of furfural to furfuryl alcohol at low cost.

[0009] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0010] One of the purposes of the present application is to provide a montmorillonite-based catalyst, which has montmorillonite as a carrier and platinum nanoparticles as an active component.

[0011] The present application uses natural clay mineral montmorillonite as a catalyst carrier, with purity ≥95%, and a small amount of impurities being silicon dioxide.

[0012] In the present application, the main component of the platinum nanoparticles is zero-valent platinum.

[0013] In the present application, the active component platinum nanoparticles in the catalyst come from chloroplatinic acid hexahydrate.

[0014] As a further preferred embodiment of the present application, the weight of the platinum nanoparticles is 0.5%-5% of the total weight of the montmorillonite-based catalyst; more preferably 1%-3%, and most preferably 3%.

[0015] The second purpose of the present application is to provide a preparation method of the above-mentioned montmorillonite-based catalyst, comprising the following steps:

[0016] The montmorillonite dispersion liquid is mixed with the solution of platinum compound, the solvent in the obtained reaction system is removed, and then the obtained reaction product is dried, ground, calcined, and reduced by H2 to obtain the montmorillonite-based catalyst.

[0017] Further, the calcination temperature is 300°C, and the time is preferably 3h;

[0018] Further, the H2 reduction temperature is 200-300°C, preferably 200°C and 300°C; and the time is preferably 2h.

[0019] As a further preferred embodiment of the present application, the platinum compound is H2PtCl6.

[0020] The solution of the platinum compound preferably uses an ethanol solution; and the montmorillonite dispersion liquid is a montmorillonite water dispersion liquid.

[0021] The more preferred preparation method of the present application has the following specific steps:

[0022] (1) A certain amount of montmorillonite powder (purity ≥95%, with a small amount of impurities being silicon dioxide) is placed in a vacuum drying oven and vacuum dried.

[0023] (2) Under the condition of continuous stirring, the treated montmorillonite powder in step (1) is weighed and added to deionized water to mix them uniformly. More specifically, 0.5g of the treated montmorillonite powder in step (1) can be added to 15ml of deionized water for preparation.

[0024] (3) The slurry stirred uniformly in step (2) is placed in an ultrasonic machine for ultrasonic treatment to uniformly disperse the montmorillonite particles in water.

[0025] (4) Take out the slurry after ultrasonic treatment in step (3), take the ethanol solution of H2PtCl6, and add it drop by drop into the montmorillonite solution under stirring, and the solution gradually changes into light yellow.

[0026] (5) Put the light yellow solution obtained in step (4) into an ultrasonic machine for ultrasonic treatment, so as to uniformly mix the solution.

[0027] (6) Stir the uniformly mixed solution after ultrasonic treatment in step (5).

[0028] (7) Put the solution after stirring in step (6) into a water bath, and heat and stir until the solvent of the mixed solution is completely evaporated.

[0029] (8) Put the catalyst sample after evaporation in step (7) into an oven for drying, so as to remove the residual water in the pores of the catalyst.

[0030] (9) Put the sample obtained in step (8) into a mortar for grinding, and collect the fine powder after grinding through a 100-mesh sieve, and then put the powder into a porcelain boat.

[0031] (10) Put the porcelain boat into a tube furnace for calcination in air, and then reduce by hydrogen, so as to obtain a black catalyst sample.

[0032] More preferably, the temperature for vacuum drying in step (1) is 80℃, and the time is 8h.

[0033] More preferably, the ethanol solution of H2PtCl6 in step (4) is 1.0g chloroplatinic acid hexahydrate dissolved in 100ml anhydrous ethanol, and the platinum content of the chloroplatinic acid hexahydrate is ≥37.5%.

[0034] More preferably, the temperature of the water bath in step (7) is set to 70℃, and the rotation speed is set to 500rpm.

[0035] More preferably, the temperature of the oven in step (8) is set to 80℃, and the time is 4-6h.

[0036] More preferably, the temperature rising rate of the tube furnace for air calcination in step (10) is 5℃ / min, the final temperature is 300℃, and the calcination time is 3h; the temperature rising rate of the tube furnace for hydrogen calcination is 5℃ / min, the final temperature is 200-300℃, preferably 300℃, and the hydrogen reduction time is 2h.

[0037] The third object of the present application is to provide the application of the above-mentioned montmorillonite-based furfural hydrogenation catalyst in the preparation of furfuryl alcohol by selective hydrogenation of furfural.

[0038] Further, the temperature of the catalytic reaction is 40-70℃, preferably 40℃, and the time is preferably 3h.

[0039] Further, the hydrogen pressure of the hydrogenation catalysis is 1.5-2 Mpa.

[0040] For the selection of the carrier: the carrier montmorillonite used in the application is a silicate itself, which is composed of two layers of silicon tetrahedron and one layer of aluminum octahedron, has the advantages of low price, high mass transfer efficiency, good chemical stability and strong electrostatic force with metal nanoclusters.

[0041] The application discloses the following technical effects:

[0042] The montmorillonite-based catalyst prepared in the application has the advantages of low preparation cost, mild reaction condition and high selectivity of furfural hydrogenation, and the production cost is significantly reduced while the selectivity of furfural hydrogenation is provided. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0044] Figure 1 The transmission electron microscope image of the montmorillonite-based furfural hydrogenation catalyst sample prepared for the embodiment 1 of the application;

[0045] Figure 2 The scanning electron microscope image of the montmorillonite-based furfural hydrogenation catalyst sample prepared for the embodiment 1 of the application;

[0046] Figure 3 The XRD image of the montmorillonite-based furfural hydrogenation catalyst sample prepared for the embodiment 1 of the application;

[0047] Figure 4 The N2-adsorption and desorption curve of the montmorillonite-based furfural hydrogenation catalyst sample prepared for the embodiment 1 of the application;

[0048] Figure 5 The XPS image of the montmorillonite-based furfural hydrogenation catalyst sample prepared for the embodiment 1 of the application. DETAILED DESCRIPTION

[0049] Now, a variety of exemplary embodiments of the application will be described in detail, which should not be considered as a limitation of the application, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the application.

[0050] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. Additionally, for a range of values of, for example, the upper limit of the range and the lower limit of the range are each specifically disclosed. Each intermediate value of the range is either specifically disclosed or can be implicitly recognized regardless of whether it was

[0051] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned herein are incorporated by reference to disclose and describe in full the methods and / or materials which are described therein. In the case of conflict between the present specification and any document incorporated by reference, the present specification controls.

[0052] Many modifications and variations of the present application described in the specific embodiments of the application can be made by those skilled in the art without departing from the spirit or scope of the application. Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application. The specification and examples are illustrative only.

[0053] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", or variations thereof, are intended to be open-ended terms that mean including, but not limited to.

[0054] The montmorillonite used in the embodiments of the present application is a natural mineral montmorillonite purified to have a purity of ≥95%, with a small amount of impurities being silicon dioxide.

[0055] Example 1

[0056] Preparation of montmorillonite-based furfural hydrogenation catalyst:

[0057] Step 1. 1 g of chloroplatinic acid hexahydrate was dissolved in anhydrous ethanol to obtain 100 ml of an ethanol solution of chloroplatinic acid, and the platinum metal content in the solution was 3.778 mg / ml.

[0058] Step 2. After the montmorillonite (vacuum dried at 80°C for 8 h) was ultrasonicated for 30 min, 3.97 ml of the ethanol solution of chloroplatinic acid was added dropwise until the montmorillonite solution turned light yellow. Subsequently, the light yellow solution was again placed in an ultrasonic machine for ultrasonication for 30 min, so that the chloroplatinic acid was uniformly dispersed in the montmorillonite solution.

[0059] Step 3: The obtained solution was stirred at room temperature for 12 hours, then the mixture was evaporated to dryness in a water bath at 70°C. After the solvent was completely evaporated, the dried sample was placed in a drying oven at 80°C for 6 hours. After the moisture inside the pores of the sample was completely evaporated, the dried sample was ground and passed through a 100-mesh sieve. The sample powder was calcined in air at 300°C for 3 hours, followed by hydrogen reduction at 300°C for 2 hours to obtain a 3wt% montmorillonite-based furfural hydrogenation catalyst.

[0060] Selective hydrogenation to prepare furfuryl alcohol:

[0061] 100 mg of the above catalyst was placed in a 100 ml high-pressure reactor, 30 ml of anhydrous ethanol was added, followed by 0.25 g of furfural. The reactor was purged with nitrogen for 2 minutes to remove air, and then the nitrogen was replaced with hydrogen. The hydrogen reaction pressure was finally set to 1.5 MPa, and the reaction was carried out at 40 °C for 3 hours. The resulting sample was subjected to chromatographic analysis, and furfuryl alcohol was obtained by collecting the sample.

[0062] Transmission electron microscopy images of montmorillonite-based furfural hydrogenation catalyst samples are shown below. Figure 1 As shown, Pt was observed to be uniformly dispersed as nanoparticles on the surface of montmorillonite; scanning electron microscope images are shown below. Figure 2 As shown, the layered structure of montmorillonite at this temperature remains intact, undamaged by loading and calcination; the XRD image is shown below. Figure 3 As shown, the characteristic peak of Pt at a loading of 3 wt% can be clearly observed, proving that Pt has been successfully loaded onto the support surface; the N2- adsorption-desorption curve is shown in the figure. Figure 4 As shown, the type IV isotherm hysteresis loop and the H4 hysteresis loop reveal a dominant slit-like porous structure; XPS images are shown below. Figure 5 As shown, after eliminating the interference of Al 2p, the XPS of Pt is mainly divided into 0 valence and +2 valence, with the percentage of 0 valence being higher than that of the higher valence state, which is more conducive to the reduction of hydrogen.

[0063] Example 2

[0064] Preparation of montmorillonite-based furfural hydrogenation catalyst:

[0065] Step 1: Dissolve 1g of chloroplatinic acid hexahydrate in anhydrous ethanol to obtain 100ml of chloroplatinic acid ethanol solution, in which the platinum metal content is 3.778mg / ml.

[0066] Step 2: After the montmorillonite (vacuum dried at 80°C for 8h) was sonicated for 30min, 0.67ml of chloroplatinic acid ethanol solution was added dropwise until the montmorillonite solution turned light yellow. The light yellow solution was then placed in the ultrasonic machine again for 30min to make the chloroplatinic acid evenly dispersed in the montmorillonite solution.

[0067] Step 3: The resulting solution was stirred at room temperature for 12h, and then the mixed solution was evaporated in a water bath pot, with the temperature set at 70°C. After the solvent was completely evaporated, the dried sample was placed in a drying oven to dry for 6h, with the temperature set at 80°C. After the moisture inside the pores of the sample was completely evaporated, the dried sample was ground and passed through a 100 mesh sieve. The sample powder was calcined in air at 300°C for 3h, and then reduced in hydrogen at 300°C for 2h to obtain a montmorillonite-based furfural hydrogenation catalyst with a loading of 0.5wt%.

[0068] Selective hydrogenation to prepare furfuryl alcohol:

[0069] Take 100mg of catalyst and place it in a 100ml high-pressure reaction kettle. Add 30ml of anhydrous ethanol, then add 0.25g of furfural. Purge the container with nitrogen for 2min to replace the air, then replace the nitrogen in the container with hydrogen, and finally set the hydrogen reaction pressure to 1.5MPa. Allow the reaction to proceed at 40°C for 3h. Perform chromatographic analysis on the reacted sample to obtain furfuryl alcohol.

[0070] Example 3

[0071] Step 1: Dissolve 1g of chloroplatinic acid hexahydrate in anhydrous ethanol to obtain a 100ml chloroplatinic acid ethanol solution. The platinum metal content in this solution is 3.778mg / ml.

[0072] Step 2: After the montmorillonite (vacuum dried at 80°C for 8h) was sonicated for 30min, 1.33ml of chloroplatinic acid ethanol solution was added dropwise until the montmorillonite solution turned light yellow. The light yellow solution was then placed in the ultrasonic machine again for 30min to make the chloroplatinic acid evenly dispersed in the montmorillonite solution.

[0073] Step 3: The resulting solution was stirred at room temperature for 12h, and then the mixed solution was evaporated in a water bath pot, with the temperature set at 70°C. After the solvent was completely evaporated, the dried sample was placed in a drying oven to dry for 6h, with the temperature set at 80°C. After the moisture inside the pores of the sample was completely evaporated, the dried sample was ground and passed through a 100 mesh sieve. The sample powder was calcined in air at 300°C for 3h, and then reduced in hydrogen at 300°C for 2h to obtain a montmorillonite-based furfural hydrogenation catalyst with a loading of 1wt%.

[0074] Selective hydrogenation to prepare furfuryl alcohol:

[0075] Take 100 mg of catalyst into 100 ml high pressure reactor, add 30 ml of anhydrous ethanol, then add 0.25 g of furfural, purge with nitrogen for 2 min to replace the air in the container, then replace the nitrogen in the container with hydrogen, and finally set the hydrogen reaction pressure to 1.5 MPa, so that the reaction is carried out at 40°C for 3 h. The sample after reaction is analyzed by chromatography, and furfuryl alcohol can be obtained by collection.

[0076] Example 4

[0077] Preparation of montmorillonite-based furfural hydrogenation catalyst:

[0078] Step 1, dissolve 1 g of chloroplatinic acid hexahydrate in anhydrous ethanol to obtain 100 ml of chloroplatinic acid ethanol solution, the platinum metal content in the solution is 3.778 mg / ml.

[0079] Step 2, ultrasonic the montmorillonite (vacuum dried at 80°C for 8h) for 30 min, then add 6.12 ml of chloroplatinic acid ethanol solution drop by drop until the montmorillonite solution turns yellow. Then put the yellow solution into the ultrasonic machine again for 30 min, so that the chloroplatinic acid is uniformly dispersed in the montmorillonite solution.

[0080] Step 3, stir the obtained solution at room temperature for 12 h, then evaporate the mixed solution in a water bath pot, set the temperature of the water bath pot to 70°C, after the solvent is completely evaporated, put the dried sample into a drying oven to dry for 6 h, set the temperature of the drying oven to 80°C, after the water in the sample is completely evaporated, grind the dried sample, pass through a 100 mesh sieve. The sample powder is calcined in air at 300°C for 3 h, and then reduced by hydrogen at 300°C for 2 h to obtain a montmorillonite-based furfural hydrogenation catalyst with a loading of 5 wt%.

[0081] Preparation of furfuryl alcohol by selective hydrogenation:

[0082] Take 100 mg of catalyst into 100 ml high pressure reactor, add 30 ml of anhydrous ethanol, then add 0.25 g of furfural, purge with nitrogen for 2 min to replace the air in the container, then replace the nitrogen in the container with hydrogen, and finally set the hydrogen reaction pressure to 1.5 MPa, so that the reaction is carried out at 40°C for 3 h. The sample after reaction is analyzed by chromatography, and furfuryl alcohol can be obtained by collection.

[0083] Example 5

[0084] Preparation of montmorillonite-based furfural hydrogenation catalyst:

[0085] Step 1, dissolve 1 g of chloroplatinic acid hexahydrate in anhydrous ethanol to obtain 100 ml of chloroplatinic acid ethanol solution, the platinum metal content in the solution is 3.778 mg / ml.

[0086] Step 2, the montmorillonite (vacuum dried at 80°C for 8h) was sonicated for 30min, then 3.97ml of chloroplatinic acid ethanol solution was added dropwise until the solution of montmorillonite became light yellow. The light yellow solution was then put into the ultrasonic machine again for 30min to make the chloroplatinic acid evenly dispersed in the solution of montmorillonite.

[0087] Step 3, the resulting solution was stirred at room temperature for 12h, then the mixed solution was evaporated in a water bath pot, the temperature of the water bath pot was set to 70°C, after the solvent was completely evaporated, the dried sample was put into a drying oven to dry for 6h, the temperature of the drying oven was set to 80°C, after the moisture in the sample was completely evaporated, the dried sample was ground and passed through a 100 mesh sieve. The sample powder was calcined in air at 300°C for 3h, followed by hydrogen reduction at 300°C for 2h to obtain a 3wt% montmorillonite-based furfural hydrogenation catalyst.

[0088] Preparation of furfuryl alcohol by selective hydrogenation:

[0089] Take 100mg of catalyst and put it into a 100ml high-pressure reaction kettle, add 30ml of anhydrous ethanol, then add 0.25g of furfural, purge the container with nitrogen for 2min to replace the air in the container, then replace the nitrogen in the container with hydrogen, and finally set the hydrogen reaction pressure to 1.5MPa, so that the reaction is carried out at 50°C for 3h. The sample after reaction was analyzed by chromatography, and furfuryl alcohol was collected.

[0090] Example 6

[0091] Preparation of montmorillonite-based furfural hydrogenation catalyst:

[0092] Step 1, dissolve 1g of chloroplatinic acid hexahydrate in anhydrous ethanol to obtain a 100ml chloroplatinic acid ethanol solution, the platinum metal content in the solution is 3.778mg / ml.

[0093] Step 2, the montmorillonite (vacuum dried at 80°C for 8h) was sonicated for 30min, then 3.97ml of chloroplatinic acid ethanol solution was added dropwise until the solution of montmorillonite became light yellow. The light yellow solution was then put into the ultrasonic machine again for 30min to make the chloroplatinic acid evenly dispersed in the solution of montmorillonite.

[0094] Step 3, the resulting solution was stirred at room temperature for 12h, then the mixed solution was evaporated in a water bath pot, the temperature of the water bath pot was set to 70°C, after the solvent was completely evaporated, the dried sample was put into a drying oven to dry for 6h, the temperature of the drying oven was set to 80°C, after the moisture in the sample was completely evaporated, the dried sample was ground and passed through a 100 mesh sieve. The sample powder was calcined in air at 300°C for 3h, followed by hydrogen reduction at 300°C for 2h to obtain a 3wt% montmorillonite-based furfural hydrogenation catalyst.

[0095] Selective hydrogenation to prepare furfuryl alcohol:

[0096] Take 100 mg of catalyst into 100 ml high pressure reactor, add 30 ml of anhydrous ethanol, then add 0.25 g of furfural, blow with nitrogen for 2 min to replace the air in the container, then replace the nitrogen in the container with hydrogen, and finally set the hydrogen reaction pressure to 1.5 MPa, so that the reaction is carried out at 60°C for 3 h. Perform chromatographic analysis on the sample after reaction, and collect furfuryl alcohol.

[0097] Example 7

[0098] Preparation of montmorillonite-based furfural hydrogenation catalyst:

[0099] Step 1: Dissolve 1 g of chloroplatinic acid hexahydrate in anhydrous ethanol to obtain 100 ml of chloroplatinic acid ethanol solution, and the platinum metal content in the solution is 3.778 mg / ml.

[0100] Step 2: Ultrasonic the montmorillonite (vacuum dried at 80°C for 8 h) for 30 min, then add 3.97 ml of chloroplatinic acid ethanol solution drop by drop until the montmorillonite solution turns yellow. Then put the yellow solution into the ultrasonic machine again for 30 min to make the chloroplatinic acid uniformly dispersed in the montmorillonite solution.

[0101] Step 3: Stir the obtained solution at room temperature for 12 h, then evaporate the mixed solution in a water bath pot, and set the temperature of the water bath pot to 70°C. After the solvent is completely evaporated, put the dried sample into a drying oven and dry it for 6 h, and set the temperature of the drying oven to 80°C. After the moisture in the sample is completely evaporated, grind the dried sample and pass it through a 100 mesh sieve. Calcine the sample powder at 300°C in air for 3 h, then reduce it at 300°C under hydrogen for 2 h to obtain a montmorillonite-based furfural hydrogenation catalyst with a loading of 3 wt%.

[0102] Selective hydrogenation to prepare furfuryl alcohol:

[0103] Take 100 mg of catalyst into 100 ml high pressure reactor, add 30 ml of anhydrous ethanol, then add 0.25 g of furfural, blow with nitrogen for 2 min to replace the air in the container, then replace the nitrogen in the container with hydrogen, and finally set the hydrogen reaction pressure to 1.5 MPa, so that the reaction is carried out at 60°C for 3 h. Perform chromatographic analysis on the sample after reaction, and collect furfuryl alcohol.

[0104] Example 8

[0105] Preparation of montmorillonite-based furfural hydrogenation catalyst:

[0106] (1) 1 g of chloroplatinic acid hexahydrate was dissolved in anhydrous ethanol to obtain 100 ml of chloroplatinic acid ethanol solution, and the platinum metal content in the solution was 3.778 mg / ml.

[0107] (2) After the montmorillonite (vacuum dried at 80°C for 8 h) was ultrasonicated for 30 min, 3.97 ml of chloroplatinic acid ethanol solution was added dropwise until the montmorillonite solution turned light yellow. Then the light yellow solution was ultrasonicated again for 30 min to make the chloroplatinic acid uniformly dispersed in the montmorillonite solution.

[0108] (3) The obtained solution was stirred at room temperature for 12 h, and then the mixed solution was evaporated in a water bath pot with a temperature set at 70°C. After the solvent was completely evaporated, the dried sample was placed in a drying oven to dry for 6 h with a temperature set at 80°C. After the moisture in the sample was completely evaporated, the dried sample was ground and passed through a 100-mesh sieve. The sample powder was calcined at 300°C in an air atmosphere for 3 h, and then reduced at 200°C in hydrogen for 2 h to obtain a montmorillonite-based furfural hydrogenation catalyst with a loading of 3 wt%.

[0109] Preparation of furfuryl alcohol by selective hydrogenation:

[0110] 100 mg of the catalyst was placed in a 100 ml high-pressure reaction kettle, 30 ml of anhydrous ethanol was added, 0.25 g of furfural was added, and the container was purged with nitrogen for 2 min to replace the air in the container, and then the nitrogen in the container was replaced with hydrogen, and finally the hydrogen reaction pressure was set to 1.5 MPa, and the reaction was carried out at 40°C for 3 h. The sample after reaction was subjected to chromatographic analysis, and furfuryl alcohol was collected.

[0111] Example 9

[0112] Preparation of montmorillonite-based furfural hydrogenation catalyst:

[0113] (1) 1 g of chloroplatinic acid hexahydrate was dissolved in anhydrous ethanol to obtain 100 ml of chloroplatinic acid ethanol solution, and the platinum metal content in the solution was 3.778 mg / ml.

[0114] (2) After the montmorillonite (vacuum dried at 80°C for 8 h) was ultrasonicated for 30 min, 3.97 ml of chloroplatinic acid ethanol solution was added dropwise until the montmorillonite solution turned light yellow. Then the light yellow solution was ultrasonicated again for 30 min to make the chloroplatinic acid uniformly dispersed in the montmorillonite solution.

[0115] (3) The obtained solution was stirred at room temperature for 12 h, and then the mixed solution was evaporated in a water bath set at 70 °C. After the solvent was completely evaporated, the dried sample was placed in a drying oven set at 80 °C for 6 h. After the moisture in the sample was completely evaporated, the dried sample was ground through a 100-mesh sieve. The sample powder was calcined in an air atmosphere at 300 °C for 3 h, and then reduced in hydrogen at 300 °C for 2 h to obtain a montmorillonite-based furfural hydrogenation catalyst with a loading of 3 wt%.

[0116] Preparation of furfuryl alcohol by selective hydrogenation:

[0117] 100 mg of the catalyst was placed in a 100-ml high-pressure reaction kettle, 30 ml of anhydrous ethanol was added, 0.25 g of furfural was added, the container was purged with nitrogen for 2 min to replace the air in the container, and then the container was replaced with hydrogen, and finally the hydrogen reaction pressure was set to 2.0 MPa. The reaction was carried out at 40 °C for 3 h. The sample after the reaction was subjected to chromatographic analysis, and furfuryl alcohol was collected.

[0118] The furfural conversion rate and furfuryl alcohol selectivity achieved by the montmorillonite-based furfural hydrogenation catalysts of Examples 1-9 are shown in Table 1.

[0119] Table 1

[0120] Furfural conversion / % Furfural conversion / % Example 1 100 97.5 Example 2 46.2 87.1 Example 3 82.7 95.7 Example 4 100 73.5 Example 5 100 97.2 Example 6 100 88.4 Example 7 100 79.6 Example 8 99.5 81.1 Example 9 100 93.5

[0121] Examples 1-4 are the effect of Pt loading on furfural conversion rate and furfuryl alcohol selectivity, the Pt loading is 0.5 wt%-5 wt%, when the Pt loading is less than 3 wt%, compared with Example 1, the furfural cannot be completely converted, and the furfuryl alcohol selectivity is not high, mainly because when the loading is low, the active sites are less, which is not conducive to the hydrogenation reaction; Examples 5-7 are the effect of temperature on furfural conversion rate and furfuryl alcohol selectivity, when the temperature increases, a part of the furfural reacts with the solvent to generate condensation products; Example 8 is due to the reduction of the reduction temperature, the reduction effect of Pt decreases, the content of zero-valent Pt decreases, which makes the selectivity of furfural reduction decrease compared with Example 1; the reaction pressure of Example 9 makes the selectivity of the catalyst decrease, mainly because more hydrogenation products are generated, therefore, compared with Example 1, the catalyst effect is affected to some extent.

[0122] Comparative Example 1

[0123] Preparation of montmorillonite-based furfural hydrogenation catalyst:

[0124] (1) 1 g of chloroplatinic acid hexahydrate was dissolved in anhydrous ethanol to obtain a 100-ml chloroplatinic acid ethanol solution, and the platinum metal content in the solution was 3.778 mg / ml.

[0125] (2) The montmorillonite (vacuum dried at 80°C for 8h) was ultrasonicated for 30min, then 3.97ml of chloroplatinic acid ethanol solution was added dropwise until the montmorillonite solution became light yellow. Then the light yellow solution was ultrasonicated for another 30min to make the chloroplatinic acid evenly dispersed in the montmorillonite solution.

[0126] (3) The obtained solution was stirred at room temperature for 12h, then the mixed solution was evaporated in a water bath pot, the temperature of which was set at 70°C. After the solvent was completely evaporated, the dried sample was placed in a drying oven and dried for 6h, the temperature of which was set at 80°C. After the moisture in the sample was completely evaporated, the dried sample was ground and passed through a 100 mesh sieve. The sample powder was directly reduced by hydrogen at 300°C for 2h to obtain a montmorillonite-based furfural hydrogenation catalyst.

[0127] Preparation of furfuryl alcohol by selective hydrogenation:

[0128] 100mg of the catalyst was placed in a 100ml high-pressure reaction kettle, 30ml of anhydrous ethanol was added, then 0.25g of furfural was added, and the container was purged with nitrogen for 2min to replace the air in the container, then the nitrogen in the container was replaced with hydrogen, and finally the hydrogen reaction pressure was set to 1.5MPa. The reaction was carried out at 40°C for 3h. The sample after the reaction was subjected to chromatographic analysis, and furfuryl alcohol was collected.

[0129] The furfural conversion rate and furfuryl alcohol selectivity comparison data of Comparative Example 1 and Example 1 are shown in Table 2:

[0130] Table 2

[0131] Sample No. Furfural conversion / % Furfural conversion / % Example 1 100 97.5 Comparative Example 1 99.1 71.8

[0132] Comparative Example 1 lacks the calcination step, so Pt cannot be well fixed on the montmorillonite, and the Pt agglomeration during reduction is intensified, which greatly affects the selectivity effect of the catalyst.

[0133] The above-described examples only describe the preferred modes of the present application and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A montmorillonite-based catalyst for the selective hydrogenation of furfural to furfuryl alcohol, characterized in that, It is prepared by the following steps: Step 1: Dissolve 1g of chloroplatinic acid hexahydrate in anhydrous ethanol to obtain 100ml of chloroplatinic acid ethanol solution, the platinum metal content in the solution is 3.778mg / ml; Step 2: After the montmorillonite that has been vacuum dried at 80℃ for 8 hours is sonicated for 30 minutes, 3.97 ml of chloroplatinic acid ethanol solution is added dropwise until the montmorillonite solution turns pale yellow. Then, the pale yellow solution is sonicated again in the sonicator for 30 minutes to ensure that the chloroplatinic acid is evenly dispersed in the montmorillonite solution. Step 3: Stir the solution obtained in Step 2 at room temperature for 12 hours, then evaporate the mixed solution to dryness in a water bath at 70°C. After the solvent is completely evaporated, place the dried reaction product in a drying oven at 80°C for 6 hours. After the moisture inside the pores of the reaction product is completely evaporated, grind the dried sample and pass it through a 100-mesh sieve. Calcine the obtained reaction product powder in air at 300°C for 3 hours, followed by hydrogen reduction at 300°C for 2 hours to obtain a 3wt% montmorillonite-based furfural hydrogenation catalyst, which is a montmorillonite-based catalyst for the selective hydrogenation of furfural to furfuryl alcohol.

2. The application of the montmorillonite-based catalyst for the selective hydrogenation of furfural to furfuryl alcohol as described in claim 1 in the selective hydrogenation of furfural to furfuryl alcohol, characterized in that, Includes the following steps: Take 100 mg of the montmorillonite-based catalyst for the selective hydrogenation of furfural to prepare furfuryl alcohol as described in claim 1 and place it in a 100 ml high-pressure reactor. Add 30 ml of anhydrous ethanol and then add 0.25 g of furfural. Purge the reactor with nitrogen for 2 min to replace the air in the high-pressure reactor. Then replace the nitrogen in the high-pressure reactor with hydrogen and finally set the hydrogen reaction pressure to 1.5 MPa. Let the reaction proceed at 40 °C for 3 h. Perform chromatographic analysis on the sample after the reaction and collect the sample to obtain furfuryl alcohol.

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