Cu / mgo-m supported catalyst, its preparation method and application

Abstract

The application belongs to the field of catalysis technology, and relates to a method for preparing furfuryl alcohol from furfural, and discloses preparation of a Cu / MgO-M supported catalyst and a method for preparing furfuryl alcohol from furfural. The prepared supported catalyst Cu / MgO-M has copper as a main active metal, MgO as a carrier, and La2O3 as a second carrier, and the nano material can catalyze preparation of furfuryl alcohol from furfural. The supported catalyst Cu / MgO-M prepared by the method has regular morphology and good hydrothermal stability, and the catalyst not only can catalyze preparation of furfuryl alcohol from furfural, but also has high catalytic activity and reusability.

Description

Technical Field

[0001] This invention belongs to the field of catalysis technology and relates to a Cu / MgO-M supported catalyst and its preparation method. Background Technology

[0002] Biomass resources, as the only renewable organic carbon source, can effectively utilize CO2 released into the atmosphere from nature or human activities, converting it into chemicals and fuels with extremely high application value. Lignocellulose is the most promising raw material among biomass derivatives. The most important subsequent derivatization process is the hydrolysis of cellulose and hemicellulose to obtain second-generation biofuels and intermediate compounds, such as glycerol, glucose, furfural, 5-hydroxymethylfurfural, and levulinic acid. Among these, furfural serves as the intermediary link between biomass resources and the chemical industry.

[0003] Furfural is typically produced by acid-catalyzing the degradation of cellulose or hemicellulose in agricultural and forestry waste into xylose, followed by dehydration of the xylose. Due to the presence of C=O bonds, C=C bonds, and a furan ring in furfural, it can be used to prepare various downstream derivatives through decarbonylation, hydrogenation, and ring-opening reactions. Furfuryl alcohol is an important fine chemical obtained through the selective hydrogenation of furfural, with high added value and wide applications. Industrially, CuCrO is mainly used. x Selective hydrogenation of furfuryl alcohol using catalysts can selectively hydrogenate the C=O double bond without affecting the C=C double bond, achieving a yield of up to 95%. However, catalysts containing the heavy metal Cr cause increasingly serious environmental problems, preventing large-scale production. In recent years, there has been growing interest in finding more environmentally friendly alternatives to CuCrO. x The Cr component in the catalyst. Besides Cr, many transition metals exhibit extremely high reactivity in the production of furfural from furfural to furfural alcohol, such as Au, Cu, Co, Ir, Ni, Pd, Pt, Rh, and Ru. Cu-based catalysts, in particular, have attracted considerable attention in this reaction. However, copper-based catalysts suffer from poor activity at low temperatures, low selectivity at high temperatures, and poor cycle stability. Therefore, developing efficient and stable copper-based catalysts to achieve efficient and selective hydrogenation of furfural to furfural alcohol is of paramount importance. Summary of the Invention

[0004] In view of this, the present invention provides a method for preparing a Cu / MgO-M supported catalyst and a method for catalyzing the preparation of furfural from furfural to furfuryl alcohol. The catalyst prepared by this method has simple steps, is easy to operate, can be prepared at room temperature, consumes little energy, and the resulting supported catalyst has uniform metal dispersion, strong hydrothermal stability, and can be recycled multiple times.

[0005] It should be noted that Cu catalysts often bind to furfural on their surface by adsorbing the C=O double bonds, exhibiting good selectivity for furfuryl alcohol. DFT calculations on the Cu surface show that furfural tends to... 1 In the (O)-aldehyde binding mode, the carbonyl group in furfural readily binds to the Cu surface via the lone pair electrons of oxygen, while the rest of the molecule is pushed away from the surface due to the net repulsion between C and Cu. Since copper has a weaker affinity for C=C bonds but a stronger affinity for C=O bonds, this binding mode is more conducive to the hydrogenation of C=O bonds. Therefore, this invention selects the non-noble metal copper as the active host metal.

[0006] Studies have found that the product distribution and hydrogenation rate of furfural depend on the affinity of the reactants for the metal and the adsorption mode (vertical or planar adsorption) of the adsorbate at specific sites on the catalyst. The reaction mechanism indicates that the activation of the C=O double bond is crucial in the hydrogenation of furfural to furfuryl alcohol. Although Cu exhibits high selectivity for furfuryl alcohol, its adsorption and activation capacity for H2 is poor, slowing down the hydrogenation process. Catalytic activity can be improved by introducing a second metal / metal oxide or selecting a non-benign support to rationally adjust the electronic structure of the metal. On the one hand, the interaction between metal nanoparticles and metal oxides alters the electron density of the metal, promoting nanoparticle formation and facilitating the availability of numerous active sites. On the other hand, the oxide / metal interface can enhance Lewis acidity and hydrogen activation capacity, improve the anti-sintering properties of metal nanoparticles, and significantly enhance the catalytic activity of single-metal catalysts. Therefore, in the catalytic production of furfuryl alcohol from furfural, it is necessary to dope with a second support to alter the metal properties; however, the optimal choice of second support to make the supported catalyst more favorable for the catalytic production of furfuryl alcohol from furfural remains unknown. Therefore, this invention develops a novel supported catalyst Cu / MgO-M and its preparation method, enabling the catalyst to efficiently catalyze the selective preparation of furfural from furfural.

[0007] Specifically, this invention uses Cu as the main metal, MgO as the main support, and La2O3 as the second support. By changing the molar ratio of the main support to the doped support, different active sites are effectively combined, maximizing the synergistic effect while the reaction proceeds smoothly.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] The first technical objective of this invention is to provide a Cu / MgO-M supported catalyst, wherein the main active metal of the supported catalyst is copper, the support is a metal oxide MgO, the second support M is La2O3, and the molar ratio between Mg and M is 0.1-8.

[0010] The second technical objective of this invention is to provide a method for preparing the Cu / MgO-M supported catalyst as described above, specifically including the following steps:

[0011] S1. Mix copper sulfate metal precursor with water, stir until the solid dissolves, then add two carriers with different molar ratios, sonicate for a period of time, and stir to obtain the corresponding mixed solution.

[0012] S2. Stop stirring and let stand overnight, then place in an oven to dry at a certain temperature;

[0013] S3. The dried product is calcined in air and reduced under the action of H2 to obtain the Cu / MgO-M supported catalyst.

[0014] Furthermore, in S1, the metal salt is CuSO4·5H2O, the support is selected from MgO, the second support (M) is selected from La2O3, and the molar ratio between Mg and M is 0.1-8. The excess impregnation method is used, the ultrasonic time is 10-30 min, and the stirring time is 10-12 h.

[0015] Furthermore, in S2, the standing time is 8–12 hours, the drying temperature is 60–80°C, and the drying time is 6–8 hours.

[0016] Furthermore, in S3, the dried product is subjected to air calcination in a muffle furnace and reduction in a tube furnace under the action of H2. The specific operations are as follows:

[0017] The heating rate of the muffle furnace is 1–5℃ / min, and the temperature is maintained at 300–600℃ for 1–4 hours; the heating rate of the tube furnace is 1–5℃ / min, and the temperature is maintained at 100–600℃ for 1–5 hours.

[0018] The third technical objective of this invention is to provide the application of the Cu / MgO-M supported catalyst as described above in the field of catalysis.

[0019] Furthermore, the Cu / MgO-M supported catalyst is applied in environmental remediation.

[0020] Furthermore, the Cu / MgO-M supported catalyst catalyzes the preparation of furfural alcohol from furfural.

[0021] Specifically, a method for catalytically preparing furfural to furfuryl alcohol is provided, wherein the method utilizes a Cu / MgO-M supported catalyst prepared as described above to catalyze the preparation of furfural to furfuryl alcohol, and the operation is as follows:

[0022] The reaction of furfural to furfuryl alcohol catalyzed by the Cu / MgO-M supported catalyst was carried out in a stainless steel high-pressure reactor. The air in the reactor was replaced with N2 several times, and H2 was introduced to replace it several times. The H2 pressure in the high-pressure reactor was maintained at a certain pressure, and the catalytic reaction was carried out by stable heating and stirring. After the reaction was completed, the product furfuryl alcohol was obtained by centrifugation, and the catalyst Cu / MgO-M was recovered at the same time. The catalyst phase can be directly recycled without post-treatment.

[0023] Furthermore, the air inside the reactor is replaced with nitrogen 2 to 5 times and with hydrogen 1 to 3 times. The H2 pressure is maintained at 1 to 4 MPa. The mass ratio of Cu / MgO-M to furfural is 1:(0.5 to 4). The reaction temperature is 70 to 130°C and the reaction time is 10 to 120 min.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The supported catalyst Cu / MgO-M prepared in this invention uses copper as the active metal, MgO as the main support, and La2O3 as the secondary support. Compared with existing technologies, La2O3 doping significantly increases the Cu... 0 The proportion of [something unclear - possibly related to catalyst composition] is [unclear - possibly related to catalyst size and adsorption]. Simultaneously, the significantly reduced size of the metal particles promotes an increase in the active surface area of ​​the catalyst, thus providing a larger active surface area conducive to the efficient adsorption of FAL and H2. The addition of La2O3 increases the strong base sites on the catalyst, which on the one hand promotes the dispersion of Cu metal, and on the other hand efficiently promotes the adsorption of FAL, thus facilitating the hydrogenation reaction. At the same time, the strong base sites have a weak adsorption effect on furfuryl alcohol, promoting the desorption of reaction products from the catalyst surface and preventing over-hydrogenation and the generation of byproducts.

[0026] Specifically, this invention uses Cu as the active metal, MgO as the main support, and La₂O₃ as the secondary support, effectively combining the two active sites of Cu and La to maximize synergistic effects. Specifically, La₂O₃ selectively adsorbs terminal carbonyl groups, and Cu decomposes H₂ into hydrogen protons, which are then transferred to La₂O₃, leading to the selective hydrogenation of the C=O double bond to generate furfuryl alcohol, greatly improving the reaction activity. After the catalytic reaction, centrifugation allows for simple and efficient separation of the catalyst and product. The catalyst phase requires no post-treatment and can be directly reused. After five reuses, the catalytic performance showed no significant decrease, indicating good recycling performance. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0028] Figure 1 This is a schematic diagram illustrating the preparation mechanism of the Cu / MgO-M supported catalyst of this invention.

[0029] Figure 2 These are TEM images of the Cu / MgO-M supported catalyst prepared in this invention: (a) Cu / MgO-La2O3-2, (b) Cu / MgO-La2O3-4, (c) Cu / MgO-La2O3-6, (d) Cu / MgO-La2O3-8; (ef) HR-TEM of Cu / MgO-La2O3-6.

[0030] Figure 3 It is an EDS elemental mapping of Cu / MgO-La2O3-6.

[0031] Figure 4 This is the XRD pattern of the Cu / MgO-M supported catalyst prepared in this invention.

[0032] Figure 5 It is an H2-TPR of MgO, La2O3, LA-0, LA-2, LA-4, LA-6 and LA-8 catalysts.

[0033] Figure 6 This is a comparison of the catalytic effects of a series of Cu-based catalysts on the selective hydrogenation of FAL under the same reaction conditions; (a) catalysts with different doped supports, (b) catalysts with different doping amounts.

[0034] Figure 7 The following are the (a) Cu 2p spectra, (b) XAES spectra corresponding to Cu LMM, (c) La 3d spectra, (d) Mg 2s spectra, and (e) O 1s spectra of LA-0, LA-2, LA-4, LA-6, and LA-8.

[0035] Figure 8 The (a) NH3-TPD and (b) CO2-TPD of MgO, La2O3, LA-0, LA-2, LA-4, LA-6 and LA-8 catalysts. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0037] The term "embodiment" used herein, as an example, is not necessarily to be construed as superior to or better than other embodiments. Performance testing in the embodiments of this application, unless otherwise specified, employs conventional testing methods in the art. It should be understood that the terminology used in this application is merely for describing particular implementations and is not intended to limit the scope of this disclosure.

[0038] Unless otherwise stated, the 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 pertains; other experimental methods and technical means not specifically mentioned herein refer to experimental methods and technical means commonly used by one of ordinary skill in the art.

[0039] To better illustrate the content of this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented even without certain specific details. In the embodiments, some methods, means, instruments, and devices well-known to those skilled in the art are not described in detail in order to highlight the main points of this application.

[0040] Without conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the resulting technical solution belongs to the content disclosed in the embodiments of this application.

[0041] This invention discloses a method for preparing a Cu / MgO-M supported catalyst and for catalyzing the preparation of furfural from furfural to furfuryl alcohol.

[0042] To better understand the present invention, the following embodiments are provided for further detailed description of the present invention, but they should not be construed as limiting the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above-described invention are also considered to fall within the protection scope of the present invention.

[0043] Example 1

[0044] S1. Mix 0.31g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 1.01g La2O3 support, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0045] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0046] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 300°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-La2O3-2.

[0047] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO-La2O3-2, 5 mL isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor 3 times and hydrogen to purge 3 times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 100°C for 40 min.

[0048] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-La2O3-2 is recovered. The catalyst phase can be directly recycled without further treatment. The furfural conversion rate is 66.4%, and the furfuryl alcohol yield is 49.1%.

[0049] The formulas for calculating furfural conversion rate and furfural alcohol yield are as follows:

[0050]

[0051] Y = S * X

[0052] Where Y is the yield of furfural; X is the conversion rate of furfural; S is the selectivity of furfuryl alcohol; n initial n is the molar amount of furfural added. final The remaining molar amount of furfuryl alcohol; m product The value represents the molar mass of the product furfuryl alcohol.

[0053] Example 2

[0054] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 0.5g La2O3 support, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0055] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0056] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 300°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-La2O3-4.

[0057] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO-La2O3-4, 5 mL isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor three times and hydrogen to purge it three times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 100 °C for 40 min.

[0058] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-La₂O₃⁻⁴ is recovered. The catalyst phase can be directly recycled without further treatment. The furfural conversion rate is 70.5%, and the furfuryl alcohol yield is 56.8%.

[0059] Example 3

[0060] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 0.34g La2O3 support, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0061] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0062] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 300°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-La2O3-6.

[0063] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO-La2O3-6, 5 mL isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor three times and hydrogen to purge it three times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 100 °C for 40 min.

[0064] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-La2O3-6 is recovered. The catalyst phase can be directly recycled without further treatment. The furfural conversion rate is 93.6%, and the furfuryl alcohol yield is 88.1%.

[0065] Example 4

[0066] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 0.25g La2O3 support, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0067] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0068] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 300°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-La2O3-8.

[0069] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO-La2O3-8, 5 mL isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor three times and hydrogen to purge it three times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 100 °C for 40 min.

[0070] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-La2O3-8 is recovered. The catalyst phase can be recycled directly without further treatment. The furfural conversion rate is 82.6%, and the furfuryl alcohol yield is 74.9%.

[0071] Example 5

[0072] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 0.34g La2O3 support, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0073] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0074] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 300°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-La2O3-6.

[0075] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO-La2O3-6, 5 mL isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor 3 times and hydrogen to purge 3 times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 90 °C for 70 min.

[0076] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-La2O3-6 is recovered. The catalyst phase can be directly recycled without further treatment. The furfural conversion rate is 100%, and the furfuryl alcohol yield is 99.9%.

[0077] Example 6

[0078] The experimental conditions and procedures were the same as in Example 5, except that the catalyst was replaced with the catalyst recovered in Example 5. Five reuse experiments were conducted. After five reuses, the furfural conversion rate was 98.7% and the furfuryl alcohol yield was 97.6%.

[0079] Example 7

[0080] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 1.01g La2O3, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0081] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0082] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 350°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-La2O3-2.

[0083] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO-La2O3-2, 5 mL isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor 3 times and hydrogen to purge 3 times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 100°C for 60 min.

[0084] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-La2O3-2 is recovered. The catalyst phase can be directly recycled without further treatment. The furfural conversion rate is 66.9%, and the furfuryl alcohol yield is 52.4%.

[0085] To further demonstrate the beneficial effects of the present invention and to better understand it, the following comparative examples and experimental cases further illustrate the technical characteristics of the supported catalyst Cu / MgO-M disclosed in this invention and its applications, but these should not be construed as limiting the invention. Any other improvements made by those skilled in the art based on the above description of the invention, without inventive effort, are also considered to fall within the protection scope of this invention.

[0086] Comparative example:

[0087] Comparative Example 1

[0088] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 0.34g neutral Al2O3, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0089] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0090] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 350°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-Al2O3-2 (middle).

[0091] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO-Al2O3-2 (middle), 5 mL isopropanol and high temperature magnetic ball into a 75 mL high temperature and high pressure stainless steel reactor. Add nitrogen to purge the air in the reactor 3 times and hydrogen to purge 3 times to maintain the pressure in the high pressure reactor at 2 MPa. Heat and stir at 100 °C for 60 min.

[0092] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-Al2O3-2 (middle phase) is recovered. The catalyst phase can be directly recycled without further treatment. The furfural conversion rate is 30.1%, and the furfuryl alcohol yield is 10.7%.

[0093] Comparative Example 2

[0094] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 0.34g alkaline Al2O3, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0095] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0096] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 350°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-Al2O3-2 (alkali).

[0097] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO-Al2O3-2 (alkali), 5 mL isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor 3 times and hydrogen to purge 3 times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 100°C for 60 min.

[0098] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-Al2O3-2 (alkali) is recovered. The catalyst phase can be recycled directly without further treatment. The furfural conversion rate is 43.8%, and the furfuryl alcohol yield is 32.8%.

[0099] Comparative Example 3

[0100] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 0.34g acidic Al2O3, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0101] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0102] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 350°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-Al2O3-2 (acid).

[0103] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO-Al2O3-2 (acid), 5 mL isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor 3 times and hydrogen to purge 3 times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 100 °C for 60 min.

[0104] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-Al₂O₃⁻ (acid) is recovered. The catalyst phase can be recycled directly without further treatment. The furfural conversion rate is 29.9%, and the furfuryl alcohol yield is 6.9%.

[0105] Comparative Example 4

[0106] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 0.5g ZnO, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0107] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0108] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 350°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-ZnO-2.

[0109] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO-ZnO-2, 5 mL isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor 3 times and hydrogen to purge 3 times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 100°C for 60 min.

[0110] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-ZnO-2 is recovered. The catalyst phase can be directly recycled without further treatment. The furfural conversion rate is 43.8%, and the furfuryl alcohol yield is 9.9%.

[0111] Comparative Example 5

[0112] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 0.54g MnO2, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0113] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0114] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 350°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-MnO2-2.

[0115] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO-MnO2-2, 5 mL isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor 3 times and hydrogen to purge 3 times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 100 °C for 60 min.

[0116] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-MnO2-2 is recovered. The catalyst phase can be directly recycled without further treatment. The furfural conversion rate is 39.2%, and the furfuryl alcohol yield is 5.8%.

[0117] Comparative Example 6

[0118] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 0.5g TiO2, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0119] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0120] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 350°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-TiO2-2.

[0121] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO-TiO2-2, 5 mL isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor 3 times and hydrogen to purge 3 times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 100 °C for 60 min.

[0122] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-TiO2-2 is recovered. The catalyst phase can be directly recycled without further treatment. The furfural conversion rate is 32.4%, and the furfuryl alcohol yield is 0.3%.

[0123] Comparative Example 7

[0124] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 1.1g CeO2, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0125] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0126] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 300°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-CeO2-2.

[0127] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO-CeO2-2, 5 mL isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor 3 times and hydrogen to purge 3 times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 100 °C for 60 min.

[0128] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-CeO2-2 is recovered. The catalyst phase can be directly recycled without further treatment. The furfural conversion rate is 34.5%, and the furfuryl alcohol yield is 3.8%.

[0129] Comparative Example 8

[0130] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 0.47g CoO, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0131] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0132] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 350°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-CoO-2.

[0133] S4. Place 0.05 mL of furfural, 0.05 g of Cu / MgO-CoO-2, 5 mL of isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor three times and hydrogen to purge it three times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 100°C for 60 min.

[0134] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-CoO-2 is recovered. The catalyst phase can be directly recycled without further treatment. The furfural conversion rate is 55.5%, and the furfuryl alcohol yield is 21.4%.

[0135] Comparative Example 9

[0136] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO and 0.82g Nb2O5, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0137] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0138] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 350°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO-Nb2O5-2.

[0139] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO-Nb2O5-2, 5 mL isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor 3 times and hydrogen to purge 3 times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 100 °C for 60 min.

[0140] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO-Nb2O5-2 is recovered. The catalyst phase can be directly recycled without further treatment. The furfural conversion rate is 44.5%, and the furfuryl alcohol yield is 15.4%.

[0141] Comparative Example 10

[0142] S1. Mix 0.21g CuSO4·5H2O with 5.0mL deionized water in a 10.0mL beaker, stir until the solid dissolves, add the oxide support, then add 0.5g MgO, sonicate for 10min, stir at room temperature and keep for 8h to obtain the corresponding mixed solution.

[0143] S2. Stop stirring and let stand overnight for 12 hours, then dry in an oven at 80°C for 6 hours.

[0144] S3. The dried product is calcined in a muffle furnace. The calcination temperature is increased to 500°C at a rate of 2°C / min and the calcination time is 3h. The obtained solid product is placed in a tube furnace for reduction. The reduction temperature is increased to 300°C at a rate of 2°C / min and the calcination time is 3h to obtain the product Cu / MgO.

[0145] S4. Place 0.05 mL furfural, 0.05 g Cu / MgO, 5 mL isopropanol and a high-temperature magnetic ball into a 75 mL high-temperature and high-pressure stainless steel reactor. Add nitrogen to purge the air in the reactor three times and hydrogen to purge it three times to maintain the pressure in the high-pressure reactor at 2 MPa. Heat and stir at 100°C for 40 min.

[0146] S5. After the reaction is complete, allow it to cool to room temperature. The product, furfuryl alcohol, is obtained by centrifugation, and the catalyst Cu / MgO is recovered. The catalyst phase can be recycled directly without further treatment. The furfural conversion rate is 56.2%, and the furfuryl alcohol yield is 36.8%.

[0147] Experimental example:

[0148] Appendix Figure 1 This represents the preparation steps of the Cu / MgO-La2O3-X supported catalyst: a certain amount of copper precursor is dissolved in deionized water, and then magnesium oxide support and lanthanum oxide (X=n) are added. Mg :n La =2, 4, 6, 8); the mixture is ultrasonicated, stirred, and allowed to stand, and then dried in an oven; the obtained solid mixture is ground into powder and calcined in a muffle furnace; the obtained target product solid powder is transferred to a tube furnace for reduction, and finally the target product Cu / MgO-La2O3-X is obtained.

[0149] Appendix Figure 2 The TEM images of the Cu / MgO-La2O3-2, Cu / MgO-La2O3-4, Cu / MgO-La2O3-6, and Cu / MgO-La2O3-8 catalysts show that the metal NPs size distributions are 3.75±0.35 nm, 2.75±0.065 nm, 2.25±0.11 nm, and 2.75±0.26 nm, respectively. It can be concluded that the metal dispersion of the Cu / MgO-La2O3-6 catalyst is the best.

[0150] HR-TEM images of Cu / MgO-La2O3-6 show lattice fringes with a spacing of 0.209 nm, confirming the presence of typical lattice spacing for metallic Cu(111). Simultaneously, characteristic lattice spacings of MgO and La2O3 were observed, with spacings of 0.149 nm and 0.338 nm, respectively, confirming that no new MgLaO is formed in the Cu / MgO-La2O3-X catalyst. x Mutually.

[0151] Furthermore, EDS characterization revealed the distribution of Cu, Mg, O, and La on the surface of the Cu / MgO-La2O3-6 catalyst. Figure 3 The smaller range of La elements suggests that La is most likely concentrated on the surface of the MgO support, while Cu is more uniformly distributed throughout the catalyst.

[0152] Appendix Figure 4X-ray diffraction analysis of Cu / MgO, Cu / MgO-La₂O₃⁻₂, Cu / MgO-La₂O₃⁻₄, Cu / MgO-La₂O₃⁻₆, and Cu / MgO-La₂O₃⁻₈ confirmed the phase composition and crystallinity of the prepared catalysts. Strong reflection peaks at 2θ = 36.86°, 42.82°, 62.16°, 74.51°, and 78.44° correspond to the (111), (200), (220), (311), and (222) crystal planes of MgO (JCPDS71-1176), respectively. The intensity of the MgO diffraction peak gradually increased with increasing Mg / La molar ratio, indicating good La dispersion on the MgO surface. Furthermore, the Cu / MgO-La₂O₃-X catalyst did not exhibit a new MgLaOx phase.

[0153] To further confirm that La plays a positive role in the reduction of Cu species in the Cu / MgO-La2O3-X sample, H2-TPR test results were obtained, such as... Figure 5 As shown. Compared to Cu / MgO, the Cu / MgO-La2O3-X catalyst exhibits higher Cu content. 2+ The reduction peak shifted from 320℃ to 250℃. Therefore, the introduction of La weakens the interaction between CuO and MgO, making CuO easier to reduce to Cu. 0 Based on TEM analysis, the structure of the Cu / MgO-La₂O₃-X catalyst was determined to be composed of MgO supported on La₂O₃, with uniformly dispersed Cu particles on its surface. Furthermore, the catalyst mainly contains MgO, while some Cu particles are distributed at the interface between La₂O₃ and MgO. 0 Therefore, three different forms of Cu 0 The reduction peaks of Cu / MgO-La2O3-X at approximately 450℃ are located at three distinct alkaline sites: the La2O3 surface, the MgO surface, and the interface between La2O3 and MgO. This reduction peak may be due to the Cu hidden at the La2O3-MgO interface. 2+ The reduction of [the substance] can only occur at relatively high temperatures due to its strong interaction with the support. This also confirms the findings of XPS analysis ([…]). Figure 7 In the process, during the reduction of the catalyst at 300℃, some Cu still remains. 2+ The presence of [something]. However, the reduction peaks near 550℃ and 700℃ correspond to the CO2 desorption peaks generated by the decomposition of La2O3 in the support.

[0154] Application testing:

[0155] Catalytic performance of Cu / MgO-La2O3-X supported catalyst for furfural hydrogenation

[0156] First, the catalytic performance of a series of different supports for Cu-based catalysts on the selective hydrogenation of FAL was compared under the same reaction conditions (e.g., Figure 6 a) Compared with other Cu-based catalysts doped with different support properties (acidic, basic, neutral), Cu / MgO-La2O3 achieved a conversion rate of 66.9% for FAL and a selectivity for FOL of 78.4%. Therefore, La2O3 was selected as the doping support for further research.

[0157] To further optimize the catalytic performance of the Cu / MgO-La2O3 catalyst, the effect of the Mg:La ratio on the selective hydrogenation reaction of FAL was investigated (e.g., Figure 6 b). With the Cu loading fixed at 5%, a catalyst Cu / MgO-La2O3-X (X = n) was prepared. Mg :n La =2, 4, 6, 8), as in Examples 1-4. When the Mg / La molar ratio increased from 1:1 to 6:1, the conversion rate of FAL increased from 66.4% to 93.6%, and the yield of FOL increased from 73.9% to 94.1%. When the Mg / La molar ratio was further increased to 8, the conversion rate of FAL decreased slightly (82.6%), and the yield of FOL was only 90.7%.

[0158] The results show that increasing the Mg / La ratio is beneficial to the formation of the product FOL. However, excess La leads to a decrease in FOL selectivity. Therefore, further research is needed on the effect of the Mg / La ratio on the structure of the Cu / MgO-La2O3-X catalyst to determine its impact on the selective hydrogenation of FAL.

[0159] Cu / MgO-La2O3-X is a bifunctional catalyst mainly composed of metal nanoparticles and an alkaline support. The former can dissociate H2 molecules into H atoms for subsequent hydrogenation reactions, while the latter provides a site for the selective adsorption of reactants. Therefore, the properties of the active component and the support play a decisive role in the product distribution of furfural selective hydrogenation. Multiple characterization data analysis shows that the excellent catalytic activity of LA-6 is mainly attributed to the addition of La, which improves Cu dispersion and promotes the reduction of metallic Cu. Based on XPS and H2-TPR results (e.g....), the catalytic activity of LA-6 is further enhanced. Figure 7 and Figure 5 As shown in the figure, La doping greatly increases Cu 0 The ratio is more than twice that of LA-0. Simultaneously, the size of the metal particles is significantly reduced, promoting a larger active surface area for the catalyst, which in turn provides a larger active surface area beneficial for the strong adsorption of FAL and H2. CO2-TPD characterization ( Figure 8 This also confirms that the addition of La increases the strong base sites of the catalyst, which promotes the dispersion of Cu metal.

[0160] In summary, La2O3, as a strong basic support, is the main adsorption site on the FAL catalyst, while highly dispersed Cu nanoparticles are beneficial to improving catalyst activity and FOL selectivity.

[0161] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The application of a Cu / MgO-M supported catalyst in the catalytic preparation of furfural from furfural to furfuryl alcohol, characterized in that, The main active metal of the supported catalyst is copper, the support is the metal oxide MgO, and the second support M is La2O3; and the molar ratio between Mg and M is 0.1-8. The preparation method of the Cu / MgO-M supported catalyst includes the following steps: S1. Mix the metal salt CuSO4·5H2O with water, stir until the solid dissolves, then add the oxide support MgO and M, sonicate, and stir to obtain a mixed solution. S2. Stop stirring, let stand overnight, and place the mixture in an oven to dry; S3. The dried product is calcined in air and reduced under the action of H2 to obtain the Cu / MgO-M supported catalyst.

2. The application of the Cu / MgO-M supported catalyst according to claim 1 in the catalytic preparation of furfural from furfural, characterized in that, In S1, the equal-volume impregnation method is used, the ultrasonic time is 10~30min, and the stirring time is 10~12h.

3. The application of the Cu / MgO-M supported catalyst according to claim 1 in the catalytic preparation of furfural from furfural, wherein in S2, the standing time is 8-12 h, the drying temperature is 60-80 °C, and the drying time is 6-8 h.

4. The application of the Cu / MgO-M supported catalyst according to claim 1 in the catalytic preparation of furfural from furfural, characterized in that, In S3, the dried product is calcined in an air-roasted muffle furnace and reduced in a tube furnace under the action of H2. The specific operation is as follows: the heating rate of the muffle furnace is 1~5℃ / min, and the temperature is raised to 300~600℃ and held for 1~4h; the heating rate of the tube furnace is 1~5℃ / min, and the temperature is raised to 100~600℃ and held for 1~5h.

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