Molecular sieve loaded Cu-Zn bimetallic catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the field of catalysts, and relates to a molecular sieve loaded Cu-Zn bimetallic catalyst and a preparation method and application thereof, efficient catalysis for preparing 2-methyl furan from furfural is achieved, the catalyst is formed by loading nano CuO and ZnO in a molecular sieve, and the mass ratio of copper to zinc is (0.5-20): 1. The molecular sieve is a ZSM-5 molecular sieve, and the silica-alumina ratio of the ZSM-5 molecular sieve is 100: (0.25-2); the loading capacity of Cu in the catalyst is 0.3 to 17.6 wt%, and the loading capacity of Zn in the catalyst is 0.08 to 6.7 wt%. By adding the metal additive Zn, the stability of the catalyst is improved, the agglomeration effect of nano metal particles is inhibited, and meanwhile, the hydrogen adsorption and hydrogen activation capacities of the catalyst are improved. The molecular sieve with the hierarchical pore structure effectively weakens the pore channel limiting effect, and the design of the catalyst has important significance in preparation of 2-methylfuran from furfural.

Description

Technical Field

[0001] The invention belongs to the field of catalysts and relates to a molecular sieve-loaded Cu-Zn bimetallic catalyst and a preparation method and application thereof. Background Art

[0002] At present, the world's main energy still relies on traditional fossil fuels, but there are problems such as serious pollution and fossil fuel depletion. There is an urgent need for an environmentally friendly and renewable new energy. The new fuel prepared from biomass has attracted widespread attention from many scholars due to its advantages such as low pollution and repeatable recycling. ( ACS Appl Mater Interfaces. 2018,10,24480 ; Catal Today. 2022,390,295). Currently, the available biomass mainly comes from agricultural waste, including corn stalks, sugarcane bagasse, etc., which have the advantages of wide sources and large reserves, but cannot be directly used for production and utilization, and need to undergo a hydrolysis process to produce furfural, levulinic acid and other products. Among them, furfural, as an important biomass-based platform compound, has the advantages of large-scale industrial production and low cost ( ACS Catal. 2020,10,4770 ； Catal Today. 2022,390,295), but its high oxygen content and low calorific value limit its further application. The production of high value-added products such as furfuryl alcohol and 2-methylfuran by hydrogenation and deoxygenation can effectively solve this problem. Among them, 2-methylfuran has the advantages of high octane number and easy storage, and is considered to be an efficient fuel material. Therefore, the preparation of efficient fuel 2-methylfuran by hydrogenation and deoxygenation of furfural is considered to be a feasible solution. ( J Catal. 2011.284,90).

[0003] At present, traditional catalysts are mainly based on precious metal catalysts, which have disadvantages such as high prices ( Org Process Res Dev.2014,18,1434), cannot meet the current industrial demand for the preparation of 2-methylfuran from furfural, and an efficient catalyst is urgently needed. We have noticed that the catalyst loaded with metal by molecular sieve has excellent catalytic performance in the preparation of 2-methylfuran by hydrogenation and deoxygenation of furfural. The metal sites in the Cu-based catalyst can efficiently adsorb and activate hydrogen to achieve the hydrogenation process. The acid sites on the surface of the molecular sieve can promote the breakage of CO to achieve catalytic dehydration. The molecular sieve has a large surface area and can provide a large number of loading sites for the metal, thereby improving the dispersion of the metal, making it extremely excellent in the catalytic effect of the reaction. However, due to the single pore size of commercial molecular sieves, there is a significant pore size restriction effect, the utilization rate of the metal sites is not high, the catalytic effect is limited, and the metal sites are prone to agglomeration when heated. During the reaction, some metal sites fall off due to weak binding, which further reduces the utilization efficiency of the metal sites. At the same time, the molecular sieve loaded with a single Cu component has the defects that the Cu nanoparticles are very easy to agglomerate when heated and the selectivity for furfural hydrogenation is not strong. ( Catal Sci Technol. 2022,12,4857). Summary of the invention

[0004] In view of the above technical problems, the present invention proposes a molecular sieve-supported Cu-Zn bimetallic catalyst and its preparation method and application. The bimetallic catalyst is constructed by adding transition metal to a Cu-based catalyst. The catalyst has a multi-level pore structure, high catalytic activity, stable structure, and high metal site dispersion, which is of great significance for the hydrogenation of furfural to prepare 2-methylfuran.

[0005] In order to achieve the above object, the technical solution of the present invention is achieved as follows: A molecular sieve-loaded Cu-Zn bimetallic catalyst is provided, wherein nano CuO and ZnO are loaded in the molecular sieve; wherein the mass ratio of copper to zinc is (0.5-20):1.

[0006] The molecular sieve is a sodium-type or H-type ZSM-5 molecular sieve, and the silicon-aluminum ratio of the ZSM-5 molecular sieve is 100:(0.25-2); the Cu loading amount of the molecular sieve-loaded Cu-Zn bimetallic catalyst is 0.3%-17.6wt%, and the Zn loading amount is 0.08%-6.7wt%.

[0007] The H-type ZSM-5 molecular sieve is a self-supporting nanosheet layered structure with a particle size of 50nm to 700nm; the average particle size of the loaded metal CuO and ZnO is 1nm to 10nm; the molecular sieve loaded Cu-Zn bimetallic catalyst has a specific surface area of ​​300m 2 / g~900m 2 / g, pore volume 0.3cm 3 / g~0.9cm 3 / g.

[0008] The loading amount of Cu in the catalyst is 0.3%~17.6wt%, and the loading amount of Zn is 0.08%~6.7wt%; the loading amount formula is: loading amount %=metal (Cu / Zn) mass*100 / molecular sieve mass.

[0009] The method for preparing the molecular sieve-supported Cu-Zn bimetallic catalyst comprises the following steps: (1) Dissolving copper salt and zinc salt in water to obtain a Cu-Zn bimetallic solution; (2) The molecular sieve and the Cu-Zn bimetallic solution are mixed and stirred, filtered, gradient dried, and calcined to obtain a molecular sieve-loaded Cu-Zn bimetallic catalyst.

[0010] In the step (1), the mass ratio of copper to zinc in the Cu-Zn bimetallic solution is (0.5-20):1, and the concentration of copper ions in the Cu-Zn bimetallic solution is 1.8-5.32wt%.

[0011] In the step (2), the mass ratio of the molecular sieve to the bimetallic solution is 1:4-4:1; the gradient drying temperature is 20°C-150°C, and is divided into 2-5 stages; the temperature of the calcination treatment I is 400°C-700°C, the calcination time is 4h-16h, and the calcination is carried out in an air atmosphere.

[0012] The molecular sieve is a sodium type or H type ZSM-5 molecular sieve, and the preparation method of the H type ZSM-5 molecular sieve is: 1) Mix and dissolve the template and aluminum source in water, add alkali and silicon source in sequence, mix well, and perform hydrothermal reaction; 2) The hydrothermal reaction product of step 1) is centrifuged, washed, and dried, and calcined to obtain a molecular sieve; then mixed with an ammonium salt solution for ion exchange; separated, washed, and dried again, and calcined to obtain a molecular sieve.

[0013] The aluminum source in step 1) is an organic aluminum compound, pseudo-boehmite, aluminum gel, an organic acid salt containing aluminum, an inorganic acid salt containing aluminum, or a complex thereof; the template includes tetrabutyl phosphine hydroxide (TBPOH) and / or tetrapropylammonium hydroxide (TPAOH); the silicon source includes one or more of silica gel, fumed silica, inorganic silicate, organic silicate, and silicic acid; and the ammonium salt in step 2) includes one or more of ammonium chloride and ammonium sulfate.

[0014] In the step 1), the molar ratio of the silicon source, the aluminum source, the alkali, the template and the water is 100:(0.25~2):(1~2):(20~35):(500~1500); the temperature of the hydrothermal treatment is 100°C~200°C, and the time of the hydrothermal treatment is 12h~120h; the temperature of the calcination treatment II in the step 2) is 400°C~700°C, and the time of the calcination treatment II is 4h~16h.

[0015] The molecular sieve-supported Cu-Zn bimetallic catalyst is used in catalyzing the hydrodeoxygenation of aldehyde compounds to prepare 2-methylfuran.

[0016] Transition metal additives (Zn, Ni, etc.) have the functions of adjusting acidity, optimizing catalyst structure, and improving target product selectivity. A small amount of transition metal can greatly improve the stability of the catalyst and inhibit the agglomeration of nano-metal particles. It is feasible to construct a bimetallic catalyst by adding transition metals to Cu-based catalysts for catalytic conversion of furfural to 2-methylfuran.

[0017] We have achieved efficient catalysis of furfural to 2-methylfuran by constructing a multi-level pore self-supporting H-type ZSM-5 molecular sieve loaded with Cu-Zn bimetallic catalyst. The addition of metal promoter Zn improves the stability of the catalyst, inhibits the agglomeration effect of nano-metal particles, and improves its hydrogen adsorption and hydrogen activation capabilities. The molecular sieve with multi-level pore structure effectively weakens the pore restriction effect. The design of this catalyst is of great significance for the preparation of 2-methylfuran from furfural.

[0018] The present invention has the following beneficial effects: 1. The present invention prepares a Cu-Zn bimetallic ZSM-5 catalyst by wet impregnation method, wherein CuO is the main active site of the catalyst, and Zn is introduced as an additive to form an alloy with Cu, thereby increasing the metal dispersion of CuO in the ZSM-5 catalyst and improving the adsorption of the active site and the reactant molecules, thereby greatly increasing the reaction rate and the selectivity of the product.

[0019] 2. The self-supporting nanosheet H-type ZSM-5 molecular sieve loaded with Cu-Zn bimetallic catalyst prepared by the present invention has the property of multi-level pores, large specific surface area and pore volume, which is beneficial to the dispersion of metals therein and forms a strong interaction force between metals, thereby enhancing the stability of the catalyst and the life of the catalyst.

[0020] 3. The Cu-Zn bimetallic ZSM-5 catalyst prepared by the present invention finally realizes the process of efficient hydrodeoxygenation of furfural into 2-methylfuran, and can be used to catalyze the efficient hydrodeoxygenation of aldehyde compounds to prepare 2-methylfuran. At 200°C, the reaction time is 60min, the catalyst dosage is 0.025g, the conversion rate of 200μL aldehyde compounds is as high as 100%, the selectivity of 2-methylfuran is as high as 95%, and the maximum yield is 95%.

[0021] 4. The preparation method of the present invention is simple, uses non-precious metals as active sites, is cheap and readily available, and has broad application prospects in catalyzing the efficient hydrodeoxygenation of aldehyde compounds to prepare 2-methylfuran. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a SEM image of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 2 of the present invention.

[0024] Figure 2 This is a metal particle size distribution diagram of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 2 of the present invention.

[0025] Figure 3 This is the XRD diagram of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 2 of the present invention.

[0026] Figure 4 This is a nitrogen adsorption-desorption isotherm diagram of the self-supporting nanosheet ZSM-5 supported Cu-Zn bimetallic catalyst prepared in Example 2 of the present invention.

[0027] Figure 5 This is the XRD diagram of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 7 of the present invention.

[0028] Figure 6 This is a nitrogen adsorption-desorption isotherm diagram of the self-supporting nanosheet ZSM-5 supported Cu-Zn bimetallic catalyst prepared in Example 7 of the present invention.

[0029] Figure 7This is a TEM image of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 7 of the present invention.

[0030] Figure 8 This is a SEM image of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 7 of the present invention.

[0031] Fig. 9 This is a diagram of the metal particle size distribution in the ZSM-5-loaded Cu-Zn bimetallic self-supporting nanosheet prepared in Example 7 of the present invention.

[0032] Fig.10 This is a SEM image of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 13 of the present invention.

[0033] Fig.11 This is the XRD diagram of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 13 of the present invention.

[0034] Fig.12 This is the nitrogen adsorption-desorption isotherm diagram of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 13 of the present invention.

[0035] Fig.13 This is the XRD diagram of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 16 of the present invention.

[0036] Fig.14 This is a SEM image of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 16 of the present invention.

[0037] Fig.15 This is the XRD diagram of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 17 of the present invention.

[0038] Fig.16 This is a TEM image of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 17 of the present invention.

[0039] Fig.17 This is the XRD diagram of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 22 of the present invention.

[0040] Fig.18 This is a SEM image of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 22 of the present invention.

[0041] Fig.19 This is a SEM image of the self-supporting nanosheet ZSM-5 loaded Cu-Zn bimetallic catalyst prepared in Example 23 of the present invention.

[0042] Fig. 20 This is a SEM image of the commercial ZSM-5 loaded Cu-Zn bimetallic catalyst obtained in Example 26 of the present invention.

[0043] Fig.21 This is the metal particle size distribution diagram of the commercial ZSM-5 loaded Cu-Zn bimetallic catalyst obtained in Example 26 of the present invention.

[0044] Fig. 22 It is a TEM image of the ZSM-5 supported Cu single metal catalyst of the self-supporting nanosheet prepared in Comparative Example 1 of the present invention.

[0045] Fig.23 This is a TEM image of the ZSM-5 supported Zn single metal catalyst of the self-supporting nanosheet prepared in Comparative Example 2 of the present invention.

[0046] Fig.24 This is the XRD diagram of the ZSM-5 loaded Zn single metal catalyst of the self-supporting nanosheet prepared in Comparative Example 2 of the present invention.

[0047] Fig.25 a is a comparison chart of the conversion rates of the catalysts prepared in Example 5, Example 7, Example 11 and Comparative Example 1 when used for the reaction of furfural to prepare 2-methylfuran at 140°C, 170°C and 200°C.

[0048] Fig.25 b is a comparative diagram of the selectivity of the catalysts prepared in Example 5, Example 7, Example 11 and Comparative Example 1 for the reaction of furfural to prepare 2-methylfuran at 140°C, 170°C and 200°C.

[0049] Fig.26 It is a comparison chart of the yields of the catalysts prepared in Example 5, Example 7, Example 11 and Comparative Example 1 when used for the reaction of furfural to prepare 2-methylfuran at 140°C, 170°C and 200°C.

[0050] Fig. 27 a is a comparison chart of the conversion rates of the catalysts prepared in Example 7, Example 23, Comparative Example 2, and Example 26 when used for the reaction of furfural to prepare 2-methylfuran at 140°C, 170°C, and 200°C.

[0051] Fig. 27b is a comparative diagram of the selectivity of the catalysts prepared in Example 7, Example 23, Comparative Example 2, and Example 26 for the reaction of furfural to prepare 2-methylfuran at 140°C, 170°C, and 200°C.

[0052] Fig.28 This is a comparison chart of the yields of the catalysts prepared in Example 7, Example 23, Comparative Example 2, and Example 26 when used for the reaction of furfural to prepare 2-methylfuran at 140°C, 170°C, and 200°C. DETAILED DESCRIPTION

[0053] The following is a detailed description of the content of the present invention. The description of the technical features recorded below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that: In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoint numerical values ​​A and B.

[0054] In this specification, unless otherwise specified, the word "multiple" in "multiple", "multiple", "plurality", etc. means a numerical value of 2 or more.

[0055] In this specification, unless otherwise specified, "%" means mass percentage.

[0056] The temperature of "room temperature" referred to in this article is generally "10℃~40℃".

[0057] [Examples 1 to 5] In this example, a series of catalysts were prepared using different silicon-aluminum ratios during the preparation of molecular sieve-supported Cu-Zn catalysts.

[0058] Weigh 0.912g Cu(NO3)2·3H2O and 0.273g Zn(NO3)2·6H2O and dissolve them in 4.215g high-purity water to prepare 5.4g solution. Stir for 3min at room temperature to obtain a solution containing Cu-Zn bimetallic.

[0059] Weigh 1.827 g of tetrapropylammonium hydroxide (TPAOH), add a certain amount of aluminum isopropoxide, and stir at room temperature for 20 minutes.

[0060] After stirring, 0.0180 g of sodium hydroxide and 5.392 g of high-purity water were added to the mixed solution. After stirring for 10 min, 6.24 g of TEOS was slowly added during stirring. Stirring was continued at room temperature for 6 h. After stirring, the mixed solution was transferred into a paired hydrothermal kettle and subjected to dynamic hydrothermal treatment at 130 °C for 48 h.

[0061] The hydrothermal product was centrifuged, washed with high-purity water for 5 times, dried in an oven at 120°C for 8 hours, and calcined at 550°C for 6 hours in a muffle furnace air range. 1 g of the product was weighed and mixed with 125 mL of NH4Cl (1 mol / L) solution, stirred at 85°C for 3 hours, washed with high-purity water by centrifugation until neutral, dried in an oven at 120°C for 8 hours, repeated 3 times, and calcined at 550°C for 6 hours in a muffle furnace air range to obtain self-supporting nanosheets of H-type ZSM-5.

[0062] 0.3 g of molecular sieve was weighed and added to 0.54 g of a solution containing Cu-Zn bimetallic, and stirred for 3 minutes to obtain a catalyst precursor of a self-supporting nanosheet H-type ZSM-5 loaded with Cu-Zn bimetallic.

[0063] The catalyst precursor was dried in an oven at 20°C, 60°C and 120°C for 12 h, and calcined at 550°C for 6 h in an air range of a muffle furnace to obtain a self-supporting nanosheet H-type ZSM-5 loaded Cu-Zn bimetallic catalyst.

[0064] The mass of TEOS used in Example 1 is 6.24 g, the mass of aluminum isopropoxide used is 0.1224 g, and the molar ratio of silicon in TEOS to aluminum in aluminum isopropoxide is 50:1.

[0065] The mass of TEOS used in Example 2 is 6.24 g, the mass of aluminum isopropoxide used is 0.0612 g, and the molar ratio of silicon in TEOS to aluminum in aluminum isopropoxide is 100:1.

[0066] The mass of TEOS used in Example 3 is 6.24 g, the mass of aluminum isopropoxide used is 0.0306 g, and the molar ratio of silicon in TEOS to aluminum in aluminum isopropoxide is 200:1.

[0067] The mass of TEOS used in Example 4 is 6.24 g, the mass of aluminum isopropoxide used is 0.0204 g, and the molar ratio of silicon in TEOS to aluminum in aluminum isopropoxide is 300:1.

[0068] The mass of TEOS used in Example 5 is 6.24 g, the mass of aluminum isopropoxide used is 0.0153 g, and the molar ratio of silicon in TEOS to aluminum in aluminum isopropoxide is 400:1.

[0069] Figure 1 This is the SEM image of Example 2. It can be observed that its morphology is approximately an irregular sphere. Figure 2 This is a metal particle size distribution diagram of the catalyst prepared in Example 2. The average particle size of the nano-metal particles obtained by statistics is 4.44 nm. Figure 3The XRD pattern of the catalyst prepared in Example 2 is shown. By comparing the PDF card (JCPDS-44-0003) in the Jade software, it can be found that it has a typical MFI molecular sieve crystal form. By comparing the standard card of CuO (PDF#80-1916), obvious characteristic diffraction peaks of CuO can be observed at 35.494° and 38.685°. Figure 4 This is the adsorption isotherm diagram of Example 2. As shown in the figure, the catalyst synthesized in Example 2 is a type IV adsorption isotherm. After data processing and analysis, it is shown that the catalyst has a porous structure composed of micropores and mesopores.

[0070] It has been verified that the average particle size of the catalyst monomers prepared in Examples 2 to 5 is 100 nm to 600 nm. The use of different silicon-aluminum ratios does not affect the crystal form of the molecular sieves. The molecular sieves all have an MFI crystal structure. The average particle size of the loaded Cu-Zn metal particles is 1 nm to 10 nm. The specific surface area of ​​the catalyst is 300 m 2 / g~900m 2 / g, pore volume 0.3cm 3 / g~0.9cm 3 / g.

[0071] [Examples 6 to 10] In this example, a series of catalysts were prepared by using metal impregnation solutions with different copper-zinc mass ratios in the process of preparing molecular sieve-loaded Cu-Zn catalysts, wherein the total Cu-Zn loading was 10% of the molecular sieve mass.

[0072] A certain amount of Cu(NO3)2·3H2O and a certain amount of Zn(NO3)2·6H2O were weighed and dissolved in a certain amount of high-purity water to prepare a 5.4 g solution. The solution was stirred at room temperature for 3 minutes to obtain a solution containing Cu-Zn bimetallic.

[0073] 2.484 g of tetrabutylphosphonium hydroxide (TBPOH) was weighed and added with 0.0612 g of aluminum isopropoxide, and the mixture was stirred at room temperature for 20 min.

[0074] After stirring, 0.0180 g of sodium hydroxide and 5.392 g of high-purity water were added to the mixed solution. After stirring for 10 min, 6.24 g of TEOS was slowly added during stirring. Stirring was continued at room temperature for 6 h. After stirring, the mixed solution was transferred into a paired hydrothermal kettle and subjected to dynamic hydrothermal treatment at 130 °C for 48 h.

[0075] The hydrothermal product was centrifuged, washed with high-purity water for 5 times, dried in an oven at 120°C for 8 hours, and calcined at 550°C for 6 hours in a muffle furnace air range. 1 g of the product was weighed and mixed with 125 mL of NH4Cl (1 mol / L) solution, stirred at 85°C for 3 hours, washed with high-purity water by centrifugation until neutral, dried in an oven at 120°C for 8 hours, repeated 3 times, and calcined at 550°C for 6 hours in a muffle furnace air range to obtain self-supporting nanosheets of H-type ZSM-5.

[0076] 0.3 g of molecular sieve was weighed and added to 0.54 g of a solution containing Cu-Zn bimetallic, and stirred for 3 minutes to obtain a catalyst precursor of a self-supporting nanosheet H-type ZSM-5 loaded with Cu-Zn bimetallic.

[0077] The catalyst precursor was dried in an oven at 20°C, 60°C and 120°C for 12 h, respectively, and calcined at 550°C for 6 h in an air atmosphere of a muffle furnace to obtain a self-supporting nanosheet H-type ZSM-5 loaded Cu-Zn bimetallic catalyst.

[0078] The mass of Cu(NO3)2·3H2O used in Example 6 is 0.376g, the mass of Zn(NO3)2·6H2O used is 0.915g, and the mass of high-purity water used is 4.109g. At this time, the mass ratio of metal Cu to metal Zn is 0.5:1. At this time, the loading amount of Cu is 3.3%, and the loading amount of Zn is 6.7%; loading amount % = metal (Cu / Zn) mass * 100 / molecular sieve mass.

[0079] In Example 7, the mass of Cu(NO3)2·3H2O used is 0.912 g, the mass of Zn(NO3)2·6H2O used is 0.273 g, and the mass of high-purity water used is 4.215 g. At this time, the mass ratio of metal Cu to metal Zn is 4: 1. At this time, the loading amount of Cu is 8%, and the loading amount of Zn is 2%.

[0080] In Example 8, the mass of Cu(NO3)2·3H2O used is 1.027 g, the mass of Zn(NO3)2·6H2O used is 0.137 g, and the mass of high-purity water used is 4.237 g. At this time, the mass ratio of metal Cu to metal Zn is 9:1. At this time, the loading amount of Cu is 9%, and the loading amount of Zn is 1%.

[0081] In Example 9, the mass of Cu(NO3)2·3H2O used was 1.069 g, the mass of Zn(NO3)2·6H2O used was 0.085 g, and the mass of high-purity water used was 4.245 g. At this time, the mass ratio of metal Cu to metal Zn was 15: 1. At this time, the loading amount of Cu was 9.4%, and the loading amount of Zn was 0.6%.

[0082] In Example 10, the mass of Cu(NO3)2·3H2O used is 1.086 g, the mass of Zn(NO3)2·6H2O used is 0.065 g, and the mass of high-purity water used is 4.249 g. At this time, the mass ratio of metal Cu to metal Zn is 20: 1. At this time, the loading amount of Cu is 9.5%, and the loading amount of Zn is 0.5%.

[0083] Figure 5 The XRD diagram of Example 7 is compared with the PDF card (JCPDS-44-0003) in the Jade software, and it can be found that it has a typical MFI molecular sieve crystal form. Compared with the standard card of CuO (PDF#80-1916), obvious characteristic diffraction peaks of CuO can be observed at 35.494° and 38.685°. Figure 6 This is the adsorption isotherm diagram of Example 7. As shown in the figure, the catalyst synthesized in Example 7 is a type IV adsorption isotherm, indicating that it has a porous structure composed of micropores and mesopores. Figure 7 The TEM image of Example 7 shows that the catalyst is a sphere formed by stacking two-dimensional ZSM-5 sheets. The specific surface area of ​​the molecular sieve catalyst is 323 m 2 / g, pore volume 0.56cm 3 / g, and the CuO metal particles are uniformly dispersed inside the molecular sieve. Figure 8 The SEM image of Example 7 is shown, and its basic morphology of lamellar stacked spheres can be observed, which is consistent with the TEM image. Fig. 9 This is a metal particle size distribution diagram of the catalyst prepared in Example 7. The average particle size of the nano-metal particles obtained by statistics is 4.56 nm.

[0084] It has been verified that the average particle size of the catalyst monomers prepared in Examples 7 to 10 is 100 nm to 600 nm, and the molecular sieve has an MFI structure; the average particle size of the loaded Cu-Zn bimetallic particles is 1 nm to 10 nm; the specific surface area of ​​the catalyst is 300 m 2 / g~900m 2 / g, pore volume 0.3cm 3 / g~0.9cm 3 / g.

[0085] [Examples 11 to 15] In this example, a series of catalysts were prepared by using different calcination temperatures and calcination times during the preparation of molecular sieve-supported Cu-Zn bimetallic catalysts.

[0086] Weigh 0.912gCu(NO3)2·3H2O and 0.273gZn(NO3)2·6H2O and dissolve them in 4.215g high-purity water to prepare 5.4g solution. Stir for 3min at room temperature to obtain a solution containing Cu-Zn bimetallic.

[0087] 2.484 g of tetrabutylphosphonium hydroxide (TBPOH) was weighed and added with 0.117 g of aluminum benzoate, and the mixture was stirred at room temperature for 20 min.

[0088] After stirring, 0.0180 g of sodium hydroxide and 5.392 g of high-purity water were added to the mixed solution. After stirring for 10 min, 6.24 g of TEOS was slowly added during stirring. Stirring was continued at room temperature for 6 h. After stirring, the mixed solution was transferred into a paired hydrothermal kettle and subjected to dynamic hydrothermal treatment at 130 °C for 48 h.

[0089] The obtained hydrothermal product was centrifuged, washed with high-purity water for 5 times, dried in an oven at 120°C for 8 hours, and calcined at a certain temperature for a certain time in the air range of a muffle furnace. 1 g of it was weighed and mixed with 125 mL of NH4Cl (1 mol / L) solution, stirred at 85°C for 3 hours, washed with high-purity water by centrifugation until neutral, dried in an oven at 120°C for 8 hours, repeated 3 times, and calcined at a certain temperature for a certain time in the air range of a muffle furnace to obtain H-type ZSM-5 of self-supporting nanosheets.

[0090] 0.3 g of molecular sieve was weighed and added to 0.54 g of a solution containing Cu-Zn bimetallic, and stirred for 3 minutes to obtain a catalyst precursor of a self-supporting nanosheet H-type ZSM-5 loaded with Cu-Zn bimetallic.

[0091] The catalyst precursor was dried in an oven at 20°C, 60°C and 120°C for 12 h respectively, and calcined at a certain temperature for a certain time in an air range of a muffle furnace to obtain a self-supporting nanosheet H-type ZSM-5 loaded Cu-Zn bimetallic catalyst.

[0092] The calcination temperature used in Example 11 is 400° C. and the calcination time is 6 h.

[0093] The calcination temperature used in Example 12 is 550°C and the calcination time is 4 hours.

[0094] The calcination temperature used in Example 13 is 550°C and the calcination time is 6 hours.

[0095] The calcination temperature used in Example 14 is 550°C and the calcination time is 16 hours.

[0096] The calcination temperature used in Example 15 is 700° C. and the calcination time is 6 h.

[0097] Fig.10The SEM image of the catalyst prepared in Example 13 shows that the catalyst is approximately irregularly spherical, and the size of the single nanocrystal is about 251 nm.

[0098] Fig.11 The XRD pattern of the catalyst prepared in Example 13 is shown. By comparing the pdf card (JCPDS-44-0003) in the Jade software, it can be found that it has a typical MFI molecular sieve crystal form. By comparing the standard card of CuO (PDF#80-1916), obvious characteristic diffraction peaks of CuO can be observed at 35.494° and 38.685°, indicating that a large number of CuO sites are attached to the molecular sieve. Fig.12 1 is the adsorption isotherm diagram of Example 13. As shown in the figure, the catalyst synthesized in Example 13 is a type IV adsorption isotherm, indicating that it has a porous structure composed of micropores and mesopores. Examples 11 to 15 prove that when the calcination conditions fall within the scope of the present invention, the molecular sieve crystal type will not change.

[0099] [Examples 16 to 20] In this example, in the process of preparing molecular sieve-supported Cu-Zn bimetallic catalyst, a series of catalysts were prepared by using different mass ratios of molecular sieve to Cu-Zn bimetallic solution.

[0100] Weigh 0.912gCu(NO3)2·3H2O and 0.273gZn(NO3)2·6H2O and dissolve them in 4.215g high-purity water to prepare 5.4g solution. Stir for 3min at room temperature to obtain a solution containing Cu-Zn bimetallic.

[0101] 2.484 g of tetrabutylphosphonium hydroxide (TBPOH) was weighed and added with 0.0612 g of aluminum isopropoxide, and the mixture was stirred at room temperature for 20 min.

[0102] After stirring, 0.0180 g of sodium hydroxide and 5.392 g of high-purity water were added to the mixed solution. After stirring for 10 min, 6.24 g of TEOS was slowly added during stirring. Stirring was continued at room temperature for 6 h. After stirring, the mixed solution was transferred into a paired hydrothermal kettle and subjected to dynamic hydrothermal treatment at 130 °C for 48 h.

[0103] The hydrothermal product was centrifuged, washed with high-purity water for 5 times, dried in an oven at 120°C for 8 hours, and calcined at 550°C for 6 hours in a muffle furnace air range. 1 g of the product was weighed and mixed with 125 mL of NH4Cl (1 mol / L) solution, stirred at 85°C for 3 hours, washed with high-purity water by centrifugation until neutral, dried in an oven at 120°C for 8 hours, repeated 3 times, and calcined at 550°C for 6 hours in a muffle furnace air range to obtain self-supporting nanosheets of H-type ZSM-5.

[0104] 0.3 g of molecular sieve was weighed and added with a certain amount of solution containing Cu-Zn bimetallic, and stirred for 3 minutes to obtain a catalyst precursor of self-supporting nanosheet H-type ZSM-5 loaded with Cu-Zn bimetallic.

[0105] The catalyst precursor was dried in an oven at 20°C, 60°C and 120°C for 12 h, and calcined at 550°C for 6 h in an air range of a muffle furnace to obtain a self-supporting nanosheet H-type ZSM-5 loaded Cu-Zn bimetallic catalyst.

[0106] The molecular sieve used in Example 16 is 0.3 g, the mass of the solution containing Cu-Zn bimetallic is 0.075 g, and the mass ratio of the molecular sieve to the bimetallic solution is 4:1. At this time, the metal loading calculated as Cu is 0.3%, and the metal loading calculated as Zn is 0.08%.

[0107] The molecular sieve used in Example 17 is 0.3 g, the mass of the solution containing Cu-Zn bimetallic is 0.3 g, and the mass ratio of the molecular sieve to the bimetallic solution is 1:1. At this time, the metal loading calculated as Cu is 4.4%, and the metal loading calculated as Zn is 1.1%.

[0108] The molecular sieve used in Example 18 is 0.3 g, the mass of the solution containing Cu-Zn bimetallic is 0.6 g, and the mass ratio of the molecular sieve to the bimetallic solution is 1:2. At this time, the metal loading calculated as Cu is 8.8%, and the metal loading calculated as Zn is 2.2%.

[0109] The molecular sieve used in Example 19 is 0.3 g, the mass of the solution containing Cu-Zn bimetallic is 0.9 g, and the mass ratio of the molecular sieve to the bimetallic solution is 1:3. At this time, the metal loading calculated as Cu is 13.2%, and the metal loading calculated as Zn is 3.3%.

[0110] The molecular sieve used in Example 20 is 0.3 g, the mass of the solution containing Cu-Zn bimetallic used is 1.2 g, and the mass ratio of the molecular sieve to the bimetallic solution is 1:4. At this time, the metal loading calculated as Cu is 17.6%, and the metal loading calculated as Zn is 4.4%.

[0111] Fig.13 The XRD pattern of Example 16 is compared with the PDF card (JCPDS-44-0003) in the Jade software, and it can be found that it has a typical MFI molecular sieve crystal form. Compared with the standard card of CuO (PDF#80-1916), no characteristic diffraction peak of CuO is observed. The reason is that the metal loading amount of Example 16 is too small, resulting in XRD failing to detect the metal diffraction peak. Fig.14 This is the SEM image of Example 16, where it can be observed that the catalyst has a nearly spherical monomer morphology. Fig.15 The XRD pattern of Example 17 is compared with the pdf card (JCPDS-44-0003) in the Jade software. It can be found that it has a typical MFI molecular sieve crystal form, and obvious characteristic diffraction peaks of CuO are observed at 35.494° and 38.685°, indicating that a large number of CuO sites are attached to the molecular sieve. Fig.16 This is the TEM image of Example 17. Similarly, a spherical structure formed by stacking of molecular sieve nanosheets of ZSM-5 can be observed. The molecular sieves prepared in different examples all have the same morphological characteristics.

[0112] It has been verified that the average particle size of the catalyst monomers prepared in Examples 16 to 19 is 100 nm to 700 nm, the molecular sieve has an MFI crystal structure, and the average particle size of the loaded Cu-Zn bimetallic particles is 1 nm to 10 nm; the specific surface area of ​​the catalyst is 300 m 2 / g~900m 2 / g, pore volume 0.3cm 3 / g~0.9cm 3 / g.

[0113] [Examples 21 to 25] In this example, a series of catalysts were prepared using different hydrothermal times during the preparation of molecular sieve-supported Cu-Zn bimetallic catalysts.

[0114] Weigh 0.912gCu(NO3)2·3H2O and 0.273gZn(NO3)2·6H2O and dissolve them in 4.215g high-purity water to prepare 5.4g solution. Stir for 3min at room temperature to obtain a solution containing Cu-Zn bimetallic.

[0115] 2.484 g of tetrabutylphosphonium hydroxide (TBPOH) was weighed and added with 0.0612 g of aluminum isopropoxide, and the mixture was stirred at room temperature for 20 min.

[0116] After stirring, 0.0180 g of sodium hydroxide and 5.392 g of high-purity water were added to the mixed solution. After stirring for 10 min, 6.24 g of TEOS was slowly added during stirring. Stirring was continued for 6 h at room temperature. After stirring, the mixed solution was transferred into a paired hydrothermal kettle and subjected to dynamic hydrothermal treatment at a certain temperature for a certain period of time.

[0117] The hydrothermal product was centrifuged, washed with high-purity water for 5 times, dried in an oven at 120°C for 8 hours, and calcined at 550°C for 6 hours in a muffle furnace air range. 1 g of the product was weighed and mixed with 125 mL of NH4Cl (1 mol / L) solution, stirred at 85°C for 3 hours, washed with high-purity water by centrifugation until neutral, dried in an oven at 120°C for 8 hours, repeated 3 times, and calcined at 550°C for 6 hours in a muffle furnace air range to obtain self-supporting nanosheets of H-type ZSM-5.

[0118] 0.3 g of molecular sieve was weighed and added to 0.54 g of a solution containing Cu-Zn bimetallic, and stirred for 3 minutes to obtain a catalyst precursor of a self-supporting nanosheet H-type ZSM-5 loaded with Cu-Zn bimetallic.

[0119] The catalyst precursor was dried in an oven at 20°C, 60°C and 120°C for 12 h, and calcined at 550°C for 6 h in an air range of a muffle furnace to obtain a self-supporting nanosheet H-type ZSM-5 loaded Cu-Zn bimetallic catalyst.

[0120] The hydrothermal temperature used in Example 21 is 100°C and the hydrothermal time is 12 hours.

[0121] The hydrothermal temperature used in Example 22 is 120°C and the hydrothermal time is 48 hours.

[0122] The hydrothermal temperature used in Example 23 is 160° C. and the hydrothermal time is 72 h.

[0123] The hydrothermal temperature used in Example 24 is 180°C and the hydrothermal time is 96 hours.

[0124] The hydrothermal temperature used in Example 25 is 200° C. and the hydrothermal time is 120 h.

[0125] Fig.17 This is the XRD diagram of Example 22. By comparing it with the PDF card (JCPDS-44-0003) in the Jade software, it can be found that it has a typical MFI molecular sieve crystal form. By comparing it with the standard card of CuO (PDF#80-1916), the characteristic diffraction peak of CuO can be observed. Fig.18 This is the SEM image of Example 22, where it can be observed that the catalyst monomer has an approximately spherical morphology. Fig.19 The SEM image of Example 23 also shows an approximately spherical morphology of the catalyst monomer. The catalysts prepared in different examples all have the same morphological characteristics. Therefore, it is judged that the catalysts prepared at different hydrothermal temperatures and hydrothermal times do not affect the crystal structure and morphological characteristics of the molecular sieve.

[0126] It has been verified that the average particle size of the catalyst monomers prepared in Examples 21 to 25 is 100 nm to 700 nm, the molecular sieve has an MFI crystal structure, and the average particle size of the loaded Cu-Zn bimetallic particles is 1 nm to 10 nm; the specific surface area of ​​the catalyst is 300 m 2 / g~900m 2 / g, pore volume 0.3cm 3 / g~0.9cm 3 / g.

[0127] Embodiment 26 In this embodiment, a Cu-Zn bimetallic catalyst was prepared by wet impregnation method using a commercial ZSM-5 molecular sieve (purchased from the catalyst plant of Nankai University) with a silicon-aluminum ratio of 100, the loading amount of metal Cu was 8%, and the loading amount of metal Zn was 2%. The specific preparation steps are as follows: Weigh 0.912gCu(NO3)2·3H2O and 0.273gZn(NO3)2·6H2O and dissolve them in 4.215g high-purity water to prepare 5.4g solution. Stir for 3min at room temperature to obtain a solution containing Cu-Zn bimetallic.

[0128] 0.3 g of commercial ZSM-5 molecular sieve was weighed, 0.54 g of a solution containing Cu-Zn bimetallic was added, and the mixture was stirred for 3 min to obtain a catalyst precursor of commercial ZSM-5 loaded with Cu-Zn bimetallic.

[0129] The catalyst precursor was dried in an oven at 20°C, 60°C and 120°C for 12 h, respectively, and calcined at 550°C for 6 h in an air range of a muffle furnace to obtain a commercial ZSM-5 loaded Cu-Zn bimetallic catalyst.

[0130] Fig. 20 The SEM image of the catalyst prepared in this example is shown. It can be observed that it has a complete hexagonal structure and obvious metal clusters attached to the surface. The average particle size of the molecular sieve catalyst is 3.74 μm and the specific surface area is 135 m 2 / g, and the total pore volume is 0.32cm 3 / g.

[0131] Fig.21 The figure shows the distribution diagram of the metal oxide particle size of the catalyst prepared in this example. The average particle size of the nano-metal particles obtained by statistics is 41.2 nm, and the metal particles are concentrated on the surface of the molecular sieve.

[0132] Comparative Example 1 In this comparative example, a self-supporting nanosheet H-type ZSM-5 Cu-loaded catalyst was prepared by wet impregnation method, and the loading amount of metal Cu was 10%. The specific preparation steps are as follows: 1.140 g of Cu(NO3)2·3H2O was weighed and dissolved in 4.26 g of high-purity water to prepare a 5.4 g solution, which was stirred at room temperature for 3 min to obtain a solution containing Cu metal.

[0133] 2.484 g of tetrabutylphosphonium hydroxide (TBPOH) was weighed and added with 0.0612 g of aluminum isopropoxide, and the mixture was stirred at room temperature for 20 min.

[0134] After stirring, 0.0180 g of sodium hydroxide and 5.392 g of high-purity water were added to the mixed solution. After stirring for 10 min, 6.24 g of TEOS was slowly added during stirring. Stirring was continued at room temperature for 6 h. After stirring, the mixed solution was transferred into a paired hydrothermal kettle and subjected to dynamic hydrothermal treatment at 130 °C for 48 h.

[0135] The hydrothermal product was centrifuged, washed with high-purity water for 5 times, dried in an oven at 120°C for 8 hours, and calcined at 550°C for 6 hours in a muffle furnace air range. 1 g of the product was weighed and mixed with 125 mL of NH4Cl (1 mol / L) solution, stirred at 85°C for 3 hours, washed with high-purity water by centrifugation until neutral, dried in an oven at 120°C for 8 hours, repeated 3 times, and calcined at 550°C for 6 hours in a muffle furnace air range to obtain self-supporting nanosheets of H-type ZSM-5.

[0136] 0.3 g of molecular sieve was weighed and added to 0.54 g of a solution containing Cu metal, and stirred for 3 minutes to obtain a catalyst precursor of a self-supporting nanosheet H-type ZSM-5 loaded with Cu.

[0137] The catalyst precursor was dried in an oven at 20° C., 60° C., and 120° C. for 12 h, respectively, and calcined at 550° C. for 6 h in an air range of a muffle furnace to obtain a self-supporting nanosheet H-type ZSM-5 supported Cu catalyst.

[0138] Fig. 22 The TEM image of Comparative Example 1 shows a spherical monomer morphology formed by stacking two-dimensional ZSM-5 sheets, with obvious metal clusters attached. The prepared catalyst has an MFI crystal form, an average particle size of 226 nm, and a mesoporous volume of 0.46 cm 3 / g, with a total specific surface area of ​​563m 2 / g.

[0139] Comparative Example 2 In this comparative example, a self-supporting nanosheet H-type ZSM-5 loaded Zn catalyst was prepared by wet impregnation method, and the loading amount of metal Zn was 10%. The specific preparation steps are as follows: Weigh 1.365 g of Zn(NO3)2·6H2O and dissolve it in 4.035 g of high-purity water to prepare a 5.4 g solution, stir it at room temperature for 3 minutes, and prepare a solution containing Zn metal.

[0140] 2.484 g of tetrabutylphosphonium hydroxide (TBPOH) was weighed and added with 0.0612 g of aluminum isopropoxide, and the mixture was stirred at room temperature for 20 min.

[0141] After stirring, 0.0180 g of sodium hydroxide and 5.392 g of high-purity water were added to the mixed solution. After stirring for 10 min, 6.24 g of TEOS was slowly added during stirring. Stirring was continued at room temperature for 6 h. After stirring, the mixed solution was transferred into a paired hydrothermal kettle and subjected to dynamic hydrothermal treatment at 130 °C for 48 h.

[0142] The hydrothermal product was centrifuged, washed with high-purity water for 5 times, dried in an oven at 120°C for 8 hours, and calcined at 550°C for 6 hours in a muffle furnace air range. 1 g of the product was weighed and mixed with 125 mL of NH4Cl (1 mol / L) solution, stirred at 85°C for 3 hours, washed with high-purity water by centrifugation until neutral, dried in an oven at 120°C for 8 hours, repeated 3 times, and calcined at 550°C for 6 hours in a muffle furnace air range to obtain self-supporting nanosheets of H-type ZSM-5.

[0143] 0.3 g of molecular sieve was weighed and added to 0.54 g of a solution containing Zn metal, and stirred for 3 minutes to obtain a self-supporting nanosheet H-type ZSM-5 loaded Zn catalyst precursor.

[0144] The catalyst precursor was dried in an oven at 20°C, 60°C and 120°C for 12 h, respectively, and calcined at 550°C for 6 h in an air range of a muffle furnace to obtain a self-supporting nanosheet H-type ZSM-5 loaded Zn catalyst.

[0145] Fig.23 The TEM image of the catalyst prepared in Comparative Example 2 is shown. It can be observed that the catalyst is a spherical monomer morphology formed by stacking two-dimensional sheet ZSM-5. The average particle size of the monomer catalyst is 278nm, and the specific surface area of ​​the catalyst is 473m 2 / g, the total pore volume of the catalyst is 0.54cm 3 / g, and the mesopore volume of the catalyst is 0.34cm 3 / g. Fig.24 The XRD pattern of the catalyst prepared in Comparative Example 2 is shown. By comparing the pdf card (JCPDS-44-0003) in the Jade software, it can be found that it has a typical MFI molecular sieve crystal form, and no other additional metal peaks are found, indicating that Zn is evenly dispersed on the H-type ZSM-5 of the self-supporting nanosheet.

[0146] Application 1-3 and comparative application example 1 The prepared molecular sieve catalyst is used for the reaction of furfural hydrodeoxygenation to obtain 2-methylfuran. The specific operation is as follows: 30mL 1,4-dioxane as solvent, 200μL furfural as reaction substrate and 105μL n-pentadecane as internal standard are mixed, stirred evenly and put into a reactor. 0.025g of the catalyst is put into the reactor, and H2 is introduced to make the pressure in the reactor reach 3MPa. The heating rate is 10℃ / min, the reaction pressure is 3MPa, the reaction time is 1h, and the obtained product is analyzed by gas chromatograph.

[0147] Application Example 1: The molecular sieve catalyst is the catalyst prepared in Example 5; Application Example 2: The molecular sieve catalyst is the catalyst prepared in Example 7; Application Example 3: The molecular sieve catalyst is the catalyst prepared in Example 11; Comparative Application Example 1: The molecular sieve catalyst is the catalyst prepared in Comparative Example 1; Fig.25 a is a conversion rate diagram of the catalyst prepared by Example 5, Example 7, Example 11, and Comparative Example 1 for the reaction of furfural to 2-methylfuran. Each catalyst reacts at different reaction temperatures, and the reaction temperatures are 140°C, 170°C, and 200°C, respectively. It can be seen from the figure that in the process of converting furfural to 2-methylfuran, the conversion rate of different catalysts increases with the increase of reaction temperature. Among them, the conversion rate of the catalyst prepared by Example 7 reached 100% at a reaction temperature of 200°C, which is much higher than that of the catalyst prepared by Example 5, Example 11, and Comparative Example 1. Among them, the conversion rate of Example 11 at a reaction temperature of 200°C is 81%, which is due to its low calcination temperature and short calcination time, resulting in the inability to completely remove the template agent, blocking part of the molecular sieve pores and causing a decrease in its reaction conversion rate. At a temperature of 200°C, the conversion rates of Example 5 and Comparative Example 1 were 92% and 72%, respectively. Example 5 was a self-supporting nanosheet H-type ZSM-5 with a Si / Al ratio of 400, and the conversion rate was lower than that of Example 7, because its molecular sieve surface lacked acidic sites, which inhibited CO breakage and slowed down the conversion of furfural to dimethylfuran. Comparative Example 1 was a self-supporting H-type ZSM-5 loaded with a single metal Cu, and its conversion rate was much lower than that of the self-supporting H-type ZSM-5 loaded with a Cu-Zn bimetallic metal, because the single Cu component loaded molecular sieve had the problem that CuO nanoparticles were very easy to agglomerate after being heated, resulting in reduced activity. Zn, as a metal additive, can not only enhance the dispersion of CuO on the molecular sieve, thereby increasing the number of active sites, but also enhance the interaction between metals, making it easier to adsorb reactant molecules, thereby improving the conversion rate of the reaction.

[0148] Fig.25b is a selectivity diagram of the catalysts prepared by Example 5, Example 7, Example 11, and Comparative Example 1 for 2-methylfuran. The selectivities of Example 5, Example 7, Example 11, and Comparative Example 1 for 2-methylfuran at 200° C. are 70%, 95%, 94%, and 85%, respectively. Among them, Example 7 has the highest selectivity for 2-methylfuran. Example 5 has a reduced selectivity for 2-methylfuran due to changes in the amount of Bronsted acid and Lewis acid of the molecular sieve caused by the change in the Si / Al ratio. When the same example is used with different reaction temperatures, it can be observed that the selectivity for 2-methylfuran increases with the increase in reaction temperature.

[0149] Fig.26 The figure is a comparison chart of the yield of 2-methylfuran in the furfural reaction catalyzed by the catalysts prepared in Example 5, Example 7, Example 11, and Comparative Example 1. At a reaction temperature of 200°C, the yields are 64%, 95%, 76%, and 61%, respectively, among which the catalyst prepared in Example 7 has the highest yield of 2-methylfuran. The figure shows that the catalysts prepared in different examples have good catalytic performance at a reaction temperature of 200°C. However, at a reaction temperature of 140°C, the catalytic performance is greatly weakened.

[0150] Application Examples 4, 5 and Comparative Application Example 2 In this application example, furfural is catalyzed to prepare 2-methylfuran at 140°C, 170°C and 200°C. The operation steps are the same as those in application example 1, except that different molecular sieve catalysts are used; wherein: Application Example 4: The molecular sieve catalyst prepared in Example 7 is used to catalyze furfural to prepare 2-methylfuran; Application Example 5: The molecular sieve catalyst prepared in Example 23 is used to catalyze furfural to prepare 2-methylfuran; Comparative Application Example 2: The molecular sieve catalyst prepared in Comparative Example 2 is used to catalyze furfural to prepare 2-methylfuran.

[0151] Application Example 6 This application example catalyzes furfural to prepare 2-methylfuran at 140°C, 170°C and 200°C. The operating steps are the same as those of Application Example 1, except that the molecular sieve catalyst used is the molecular sieve catalyst prepared in Example 26 for catalyzing furfural to prepare 2-methylfuran.

[0152] Fig. 27a is a graph showing the conversion rate of the catalysts prepared in Example 7, Example 23, Comparative Example 2, and Example 26 for the preparation of 2-methylfuran from furfural at 140°C, 170°C, and 200°C, respectively. As shown in the figure, at 200°C, the conversion rates of the catalysts prepared in Example 7, Example 23, Comparative Example 2, and Example 26 are 100%, 100%, 42%, and 87%, respectively. The furfural in Example 7 and Example 23 is completely converted, indicating that changing the hydrothermal temperature and hydrothermal time has little effect on the results of the furfural catalytic reaction, and both have high catalytic activity. Comparative Example 2 is a self-supporting nanosheet H-type ZSM-5 loaded with monometallic Zn, which has the lowest catalytic activity because the main active sites of the reaction are provided by the CuO active sites, and the monometallic Zn-loaded molecular sieve cannot achieve the conversion of furfural. Example 26 is commercial ZSM-5 with a hexagonal morphology. Since it only has a single micropore and its specific surface area and pore volume are much smaller than those of the self-supporting nanosheet H-type ZSM-5 in Example 7, the reactant molecules cannot contact the catalytic active sites and the metal particles aggregate on its surface, resulting in a slow conversion rate.

[0153] Fig. 27 b is a selectivity diagram of the catalysts prepared in Example 7, Example 23, Comparative Example 2, and Example 26 for the reaction of furfural to prepare 2-methylfuran at 140°C, 170°C, and 200°C, respectively. As shown in the figure, at 200°C, the 2-methylfuran selectivity of the catalysts prepared in Example 7, Example 23, Comparative Example 2, and Example 26 are 95%, 92%, 46%, and 80%, respectively. Similarly, Example 7 and Example 23 maintain similar selectivity. At the same time, it can be observed that at low temperatures, the catalysts all have lower selectivity. In the process of furfural conversion to 2-methylfuran, there is an intermediate product of furfuryl alcohol, and the low temperature causes the intermediate product furfuryl alcohol to be unable to be converted to 2-methylfuran, thus showing a lower selectivity for 2-methylfuran. Similar to the conversion rate, the selectivity of Comparative Example 2 is the lowest, and Example 26 has a slightly reduced selectivity for 2-methylfuran than Example 7 and Example 23 due to the confinement effect of its molecular sieve and metal aggregation.

[0154] Fig.28The following is a comparison chart of the yield of 2-methylfuran in the furfural reaction catalyzed by the catalysts prepared in Example 7, Example 23, Comparative Example 2, and Example 26. The yields of Example 7, Example 23, and Example 26 are 95%, 92%, and 71%, respectively. At 140°C, the yield of 2-methylfuran of the catalyst prepared in Comparative Example 2 is 2%, which once again illustrates that the loaded Zn has little effect on the catalytic hydrodeoxygenation of furfural to 2-methylfuran. At 200°C, the yield of Comparative Example 2 increases to 19%. As shown in the figure, as the reaction temperature increases, the yields of different catalysts all increase. Therefore, for different catalysts prepared by the present invention in the furfural hydrodeoxygenation reaction, increasing the reaction temperature can increase the yield of 2-methylfuran.

[0155] The molecular sieve catalyst provided by the invention can be prepared industrially and can be used for efficiently catalyzing furfural to prepare 2-methylfuran.

[0156] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

[0157] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A molecular sieve supported Cu-Zn bimetallic catalyst, characterized in that: The molecular sieve-loaded Cu-Zn bimetallic catalyst is nano-CuO and ZnO loaded in the molecular sieve; wherein the mass ratio of copper to zinc is (0.5-20):

1.

2. The molecular sieve-supported Cu-Zn bimetallic catalyst according to claim 1, characterized in that: The molecular sieve is a sodium-type or H-type ZSM-5 molecular sieve, and the silicon-aluminum ratio of the ZSM-5 molecular sieve is 100:(0.25-2); the Cu loading amount of the molecular sieve-loaded Cu-Zn bimetallic catalyst is 0.3%-17.6wt%, and the Zn loading amount is 0.08%-6.7wt%.

3. The molecular sieve-supported Cu-Zn bimetallic catalyst according to claim 2, characterized in that: The H-type ZSM-5 molecular sieve is a self-supporting nanosheet layered structure with a particle size of 50nm to 700nm; the average particle size of the loaded CuO and ZnO is 1nm to 10nm; the molecular sieve loaded Cu-Zn bimetallic catalyst has a specific surface area of ​​300m 2 / g~900m 2 / g, pore volume 0.3cm 3 / g~0.9cm 3 / g.

4. The method for preparing the molecular sieve-supported Cu-Zn bimetallic catalyst according to any one of claims 1 to 3, characterized in that: The steps include: (1) Dissolving copper salt and zinc salt in water to obtain a Cu-Zn bimetallic solution; (2) The molecular sieve and the Cu-Zn bimetallic solution are mixed and stirred, filtered, gradient dried, and calcined to obtain a molecular sieve-loaded Cu-Zn bimetallic catalyst.

5. The method for preparing the molecular sieve-supported Cu-Zn bimetallic catalyst according to claim 4, characterized in that: In the step (1), the mass ratio of copper to zinc in the Cu-Zn bimetallic solution is (0.5-20):1, and the concentration of copper ions in the Cu-Zn bimetallic solution is 1.8-5.32wt%.

6. The method for preparing the molecular sieve-supported Cu-Zn bimetallic catalyst according to claim 5, characterized in that: In the step (2), the mass ratio of the molecular sieve to the bimetallic solution is 1:4-4:1; the gradient drying temperature is 20°C-150°C, and is divided into 2-5 stages; the temperature of the calcination treatment I is 400°C-700°C, the calcination time is 4h-16h, and the calcination is carried out in an air atmosphere.

7. The method for preparing the molecular sieve-supported Cu-Zn bimetallic catalyst according to claim 6, characterized in that: The molecular sieve is a sodium type or H type ZSM-5 molecular sieve, and the preparation method of the H type ZSM-5 molecular sieve is: 1) Mix and dissolve the template and aluminum source in water, add alkali and silicon source in sequence, mix well, and perform hydrothermal reaction; 2) The hydrothermal reaction product of step 1) is centrifuged, washed, dried, and calcined; and then mixed with an ammonium salt solution for ion exchange; Separate, wash, dry and calcine again to obtain molecular sieve.

8. The method for preparing the molecular sieve-supported Cu-Zn bimetallic catalyst according to claim 7, characterized in that: In step 1), the aluminum source is an organic aluminum compound, pseudo-boehmite, aluminum gel, an organic acid salt containing aluminum, an inorganic acid salt containing aluminum or a complex thereof; the template is tetrabutyl phosphine hydroxide and / or tetrapropylammonium hydroxide; the silicon source is one or more of silica gel, fumed silica, inorganic silicate, organic silicate, and silicic acid; and the ammonium salt in step 2) is ammonium chloride and / or ammonium sulfate.

9. The method for preparing the molecular sieve-supported Cu-Zn bimetallic catalyst according to claim 7, characterized in that: In the step 1), the molar ratio of the silicon source, the aluminum source, the alkali, the template and the water is 100:(0.25-2):(1-2):(20-35):(500-1500); the temperature of the hydrothermal reaction is 100°C-200°C, and the time is 12h-120h; the temperature of the calcination treatment II in the step 2) is 400°C-700°C, and the time is 4h-16h.

10. Use of the molecular sieve-supported Cu-Zn bimetallic catalyst according to any one of claims 1 to 3 in catalyzing the hydrodeoxygenation of aldehyde compounds to prepare 2-methylfuran.

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