A gold-loaded iron-copper oxide catalyst and its preparation method and application

Abstract

The present invention relates to an iron-copper oxide-supported gold catalyst, its preparation method, and application. The catalyst comprises the following steps: sequentially adding ferric nitrate nonahydrate and copper nitrate trihydrate to a solvent at a molar ratio of 1:1, adjusting the pH, and stirring the reaction. The catalyst then undergoes filtration, drying, grinding, and calcination to produce a powdered solid. Subsequently, a HAuCl4·3H2O solution and a carrier are added to another solvent, followed by stirring, reaction, washing, filtration, and drying to produce the final catalyst. This preparation method is simple to operate, low-cost, and exhibits high selectivity and conversion under normal pressure and low temperature conditions. The catalyst is suitable for reactions such as the preparation of furfural from furfuryl alcohol. The preparation method has practical application value and is environmentally friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to an iron-copper oxide-loaded gold catalyst and a preparation method and application thereof. Background Art

[0002] A stable energy supply is crucial for economic and social development. Currently, humanity's primary energy source still comes from non-renewable fossil fuels such as crude oil, coal, and natural gas. However, the widespread mining and combustion of fossil fuels worldwide has led to increasingly serious environmental pollution, energy shortages, and global warming. To reduce global dependence on fossil fuels and gradually address the resulting environmental problems, the catalytic conversion of renewable lignocellulosic resources into biofuels and chemicals has garnered worldwide attention. In recent years, pentosan-derived furfural, a versatile platform compound, has garnered intensive research. Catalytic activation of the various functional groups in furfural yields a variety of high-value fine chemicals with broad applications in the polymer, energy, pharmaceutical, and fragrance industries. Furfuryl alcohol, in particular, has garnered significant attention for its use in the preparation of furan resins and as a solvent, dispersant, and wetting agent for dyes, varnishes, phenolic resins, and furan resins.

[0003] Furfuryl alcohol is the primary product of furfural production. Further hydrogenation can produce 1,2-pentanediol, 1,5-pentanediol, tetrahydrofurfuryl alcohol, 2-methylfuran, and 2-methyltetrahydrofuran. Furthermore, furfuryl alcohol is widely used in the synthesis of polyesters, furan resins, synthetic fibers, and intermediate compounds for aerospace fuels and pharmaceuticals. Furfuryl alcohol can also be used as a solvent or dispersant for dyes, varnishes, and phenolic resins. In the chemical and light industries, it can be used to synthesize adhesives, carbon binders, synthetic rubber, and organic synthesis materials for the mechanical casting industry. It can also be used as a rocket fuel additive.

[0004] Furfuryl alcohol can typically be prepared by hydrogenating furfural under catalytic conditions. However, furfural is a reactive organic compound containing an aldehyde group, making it susceptible to over-hydrogenation, resulting in a complex product distribution and numerous by-products. The hydroxyl group of the target product, furfuryl alcohol, can be deeply reduced to form 2-methylfuran, or the furan ring can be over-hydrogenated to form tetrahydrofurfuryl alcohol. This results in low yields of the target product, furfuryl alcohol, and makes separation and purification extremely difficult.

[0005] Therefore, the industry has made numerous attempts to research and develop catalysts to improve the selectivity of furfuryl alcohol. The high efficiency of existing catalytic systems relies on the loading of expensive precious metals. Currently, basic research and development for this type of catalytic reaction focuses primarily on loading expensive precious metals such as platinum and palladium. These catalysts also require high loadings, significantly increasing their cost. Using lower-cost non-precious metals such as cobalt, nickel, and zinc as active catalyst components requires simultaneous high temperatures, high pressures, and long reaction times to ensure complete reaction. The resulting waste metals can pollute water bodies, and the high catalyst requirements result in low economic returns.

[0006] The industrial catalyst used to catalyze furfural to furfuryl alcohol is a Cu-Cr (CuCr2O4) catalyst, which can achieve a furfuryl alcohol yield of approximately 90% at 180°C and 7-10 MPa H2 pressure. However, the high-temperature and high-pressure reaction conditions are energy-intensive and risky. Furthermore, while Cu is inexpensive, Cr is toxic, and the discharge of reaction wastewater can cause irreversible damage to soil and water. Therefore, there is an urgent need to develop green, heterogeneous catalysts that can achieve highly selective catalytic conversion of furfural to furfuryl alcohol under mild reaction conditions at ambient pressure and low temperature.

[0007] Based on the above background technology, the present invention proposes an iron-copper oxide-loaded gold catalyst and its preparation method and application, and develops a high-efficiency green catalyst that can take into account both cost and efficiency. Summary of the Invention

[0008] To address the above technical problems, the present invention designs an iron-copper oxide-loaded gold catalyst, its preparation method, and its application, to achieve highly selective catalytic conversion of furfural to furfuryl alcohol under mild reaction conditions at normal pressure and low temperature. Furthermore, the catalyst reaction process does not require the addition of any corrosive acid solution, and no acidic or alkaline substances or toxic byproducts are produced throughout the process. The reaction poses little hazard to the reaction operators and has negligible environmental pollution.

[0009] In order to achieve the above technical objectives, the present invention is implemented by the following technical solutions: a method for preparing an iron-copper oxide-loaded gold catalyst, which comprises the following steps:

[0010] S1. Adding a solvent to the reaction apparatus;

[0011] S2. Ferric nitrate nonahydrate and copper nitrate trihydrate are sequentially added to the solvent in S1, wherein the molar ratio of ferric nitrate nonahydrate to copper nitrate trihydrate is 1:1;

[0012] S3. Add an appropriate amount of NaOH solution, adjust the pH value of the solution to 11-12, and stir for not less than two hours;

[0013] S4. After stirring, the reactant in S3 was filtered using a sand core funnel to obtain solid particles;

[0014] S5. The solid particles after filtration are placed in an oven for drying until a dry solid is obtained;

[0015] S6. Grind the solid in S5 into a powder;

[0016] S7. The powder in S6 is placed in a muffle furnace and calcined to form a carrier;

[0017] S8. Take another reaction apparatus and add a solvent;

[0018] S9. Add HAuCl4·3H2O solution to the solvent in S8;

[0019] S10. The carrier in S7 and an appropriate amount of NaBH4 were added to the solution in S9 and stirred at room temperature for 2 hours to allow the gold ions to fully react with the carrier;

[0020] S11. The solution obtained in S10 was washed and filtered to obtain a solid catalyst;

[0021] S12. Place the solid catalyst in S11 into a vacuum drying oven and dry it overnight to obtain the final catalyst.

[0022] Preferably, the solvent in step S1 is deionized water, and the additive amount is 200 ml.

[0023] Preferably, the oven temperature in step S5 is 80°C.

[0024] Preferably, the calcination treatment conditions in step S7 are: temperature: 400° C., time: not less than 4 hours.

[0025] Preferably, the solvent in step S8 is deionized water, and the additive amount is 200 ml.

[0026] Preferably, in step S9, 1 mL of 5 mg / mL HAuCl4·3H2O solution is added.

[0027] Preferably, the amount of the carrier in S7 added in step S10 is 0.5 g.

[0028] Preferably, the temperature of the vacuum drying oven in step S12 is 60°C.

[0029] The iron-copper oxide-supported gold catalyst is used in the highly selective catalytic conversion of furfural to prepare furfuryl alcohol under mild reaction conditions at normal pressure and low temperature.

[0030] The beneficial effects of the present invention are:

[0031] 1. The catalyst proposed in the present invention does not require the addition of any corrosive acid solution during the reaction process, and no acidic or alkaline substances or toxic by-products are produced throughout the process. The reaction poses little harm to the reaction operators and the environmental pollution is negligible.

[0032] 2. The carrier used for the catalyst in the present invention is low-cost, low-toxic and harmless iron-copper oxide, so it is very easy to separate the product and recover the catalyst.

[0033] 3. The catalyst preparation process of the present invention is simple, and the price and availability of the carrier and metal are relatively low. The mass fraction of the precious metal loading is 1%, which is a small loading amount and extremely low cost.

[0034] 4. The present invention optimizes the preparation conditions of the catalyst; adjusts the effect of the ratio of iron and copper oxides on the reaction; achieves high dispersion of precious metal nanoparticles at the microscopic level and enables the reaction to obtain the best conversion rate and yield.

[0035] 5. The present invention optimizes the catalytic reaction conditions of the catalyst. Under the reaction conditions of 120°C, 1 bar hydrogen pressure, and 4 hours, the conversion rate of the reactant furfural reaches 99%, the yield of the target product furfuryl alcohol is as high as 99%, and there are no by-products. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. 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 creative work.

[0037] Figure 1 This is a schematic diagram of the reaction pathway for furfural to furfuryl alcohol and the over-hydrogenation products;

[0038] Figure 2 is a transmission electron microscopy image of 1% Au / FeCuOx catalyst;

[0039] Figure 3 This is the particle size distribution diagram of iridium-ruthenium alloy nanoparticles corresponding to 1% Au / FeCuOx catalyst. DETAILED DESCRIPTION

[0040] Example 1

[0041] This embodiment provides an iron-copper oxide-supported gold catalyst and a preparation method thereof, comprising the following steps:

[0042] (1) Add 200 ml of deionized water to a 400 ml beaker.

[0043] (2) Add ferric nitrate nonahydrate and copper nitrate trihydrate to the beaker in sequence at a molar ratio of 1:1.

[0044] (3) Add an appropriate amount of NaOH solution to adjust the pH value of the solution to 11-12, and stir the reaction for two hours.

[0045] (4) After stirring, filter using a sand core funnel to obtain solid particles.

[0046] (5) The obtained solid particles were placed in an oven at 80°C for drying until a dry sample was obtained.

[0047] (6) Grind the dried sample to obtain a powdered carrier.

[0048] (7) The carrier is placed in a muffle furnace and calcined at 400° C. for 4 hours to form a carrier.

[0049] (8) Take another beaker and add 200 ml of deionized water to the 400 ml beaker.

[0050] (9) Add 1 mL of 5 mg / mL HAuCl4·3H2O solution to the beaker.

[0051] (10) Add 0.5 g of the support prepared above and add an appropriate amount of NaBH4.

[0052] (11) Stir at room temperature for 2 hours to allow the gold ions to fully react with the carrier.

[0053] (12) The reaction solution is washed and filtered to obtain a solid catalyst.

[0054] (13) The solid catalyst was placed in a vacuum drying oven and dried overnight to obtain the final catalyst.

[0055] Example 2:

[0056] Based on Example 1, the performance test of the 1% Au / FeCuOx catalyst was carried out, and the specific process was as follows:

[0057] Into the polytetrafluoroethylene liner of a high-pressure reactor, 30 mg of catalyst, 5 mL of isopropanol solvent, 1 mmol of furfural, and a magnetic stirring rod were sequentially added. After the reactor was assembled, it was purged three times with 0.5 MPa of argon. Residual gases in the reactor were then extracted using a high-pressure pump. The reactor was then connected to a hydrogen cylinder and purged three times with 1 bar of hydrogen. The aeration process was then maintained for approximately 1 minute. Finally, the reactor was placed in a high-temperature magnetic stirring oil bath set at 120°C and 800 rpm for 4 hours. After the 4-hour reaction, the reactor was cooled in ice water for 10-15 minutes to release the gases. The reaction liquid was then aspirated with a syringe and filtered through a 0.45 nm filter to obtain a filtrate. The filtrate was quantitatively analyzed using a Thermo Fisher TRACE 1310 gas chromatograph equipped with an HP-1 capillary column and an FID detector.

[0058] Example 3

[0059] Based on Example 2, this example changes the molar composition ratio of iron and copper oxides, and the results obtained by gas chromatography are shown in the following table.

[0060] Table 1 Effect of the composition of iron-copper oxides in the catalyst on its performance

[0061]

[0062] The reaction results in the table above demonstrate that the synergistic effect of the iron-copper bimetallic catalyst significantly improves furfural conversion, with the optimal catalytic effect achieved when the molar ratio of iron and copper oxides is 1:1. Excessive amounts of iron and copper reduce furfural conversion. If the reaction does not proceed when hydrogen is replaced with argon, this indicates that hydrogen is required as a hydrogen source.

[0063] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing an iron-copper oxide-supported gold catalyst, comprising the following steps: S1. Adding a solvent to the reaction apparatus; S2. Ferric nitrate nonahydrate and copper nitrate trihydrate are sequentially added to the solvent in S1, wherein the molar ratio of ferric nitrate nonahydrate to copper nitrate trihydrate is 1:1; S3. Add an appropriate amount of NaOH solution, adjust the pH value of the solution to 11-12, and stir for not less than two hours; S4. After stirring, the reactant in S3 was filtered using a sand core funnel to obtain solid particles; S5. The solid particles after filtration are placed in an oven for drying until a dry solid is obtained; S6. Grind the solid in S5 into a powder; S7. The powder in S6 is placed in a muffle furnace and calcined to form a carrier; S8. Take another reaction apparatus and add a solvent; S9. Add HAuCl4·3H2O solution to the solvent in S8; S10. The carrier in S7 and an appropriate amount of NaBH4 were added to the solution in S9 and stirred at room temperature for 2 hours to allow the gold ions to fully react with the carrier; S11. The solution obtained in S10 was washed and filtered to obtain a solid catalyst; S12. Place the solid catalyst in S11 into a vacuum drying oven and dry it overnight to obtain the final catalyst.

2. The method for preparing the iron-copper oxide-supported gold catalyst according to claim 1, wherein: In step S1, the solvent is deionized water, and the additive amount is 200 ml.

3. The method for preparing the iron-copper oxide-supported gold catalyst according to claim 1, wherein: The oven temperature in step S5 is 80°C.

4. The method for preparing the iron-copper oxide-supported gold catalyst according to claim 1, wherein: The calcination treatment conditions in step S7 are: temperature: 400° C., time: not less than 4 hours.

5. The method for preparing the iron-copper oxide-supported gold catalyst according to claim 1, wherein: In step S8, the solvent is deionized water, and the additive amount is 200 ml.

6. The method for preparing the iron-copper oxide-supported gold catalyst according to claim 1, wherein: In step S9, 1 mL of 5 mg / mL HAuCl 4 ·3H 2 O solution was added.

7. The method for preparing the iron-copper oxide-supported gold catalyst according to claim 1, wherein: The amount of the carrier in S7 added in step S10 is 0.5 g.

8. The method for preparing the iron-copper oxide-supported gold catalyst according to claim 1, wherein: The temperature of the vacuum drying oven in step S12 is 60°C. 9 . The iron-copper oxide-supported gold catalyst prepared according to the method for preparing an iron-copper oxide-supported gold catalyst according to claim 1 .

10. Use of the iron-copper oxide-supported gold catalyst according to claim 9 in the highly selective catalytic conversion of furfural to furfuryl alcohol under mild reaction conditions at normal pressure and low temperature.

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