A catalyst for decarbonylation of furfural, a preparation method and a process for preparing furan using the catalyst

Abstract

The present application relates to furan preparation technical field, specifically to a kind of furfural decarbonylation catalyst, preparation method and utilize the catalyst preparation furan process.The catalyst includes carrier and active component supported on it, with the mass of the carrier, Pt 0.2%‑0.6%, Co 4%‑8%, Al2O3 74%‑85%, ZrO2 11%‑16%, CeO2 4%‑13%.The present application adopts structural aid ZrO2 and CeO2 to modify Al2O3 carrier, obtains acid moderate composite oxide carrier, can avoid the influence of furfural polymerization and the activity and stability of catalyst;Using Co as auxiliary active component, under the premise of reducing the dosage of main active component Pt, ensure catalytic effect, not only reduce the cost of catalyst, more importantly, it can improve the conversion rate of furfural and furan selectivity in furfural decarbonylation reaction, ensure high furan yield.

Description

Technical Field

[0001] This invention relates to the field of furan preparation technology, specifically to a furfural decarbonylation catalyst, a preparation method, and a process for preparing furan using the catalyst. Background Technology

[0002] Furan is an important intermediate compound widely used in many important organic synthesis and pharmaceutical production processes. It can be used to prepare pyrrole, thiophene, or tetrahydrofuran, among others. Tetrahydrofuran is an important derivative of furan and can be used as a solvent. It can also be used to prepare polytetramethylene glycol, an important component of a series of polyurethane elastomers and polyurethane fibers. Furan can also be used to synthesize scopolamine and another alkaloid, atropine.

[0003] There are two main technical routes for the production of furan (Industrial Catalysis, 2001, 3(3), 20-25; Fine Petrochemicals, 2002, 3, 14). One route is produced by catalytic oxidation of butadiene or crotonaldehyde, and the other is produced by catalytic decarbonylation of furfural. The former has been phased out due to its low conversion rates of butadiene and crotonaldehyde and low selectivity of furan; the latter, the furfural method, has high decarbonylation conversion rates and high furan selectivity, and is the mainstream production technology route.

[0004] The production of furfural from furfural through decarbonylation can be divided into liquid-phase decarbonylation and gas-phase decarbonylation. Liquid-phase decarbonylation generally does not require the introduction of other gases, but it necessitates a dedicated automatic sampler and reflux condenser to control the amount of furfural in the reactor and to reflux unreacted furfural. Both methods use similar catalysts, currently both being precious metal Pd catalysts, and the resulting furan yields are essentially the same. However, compared to gas-phase decarbonylation, the biggest drawback of liquid-phase decarbonylation is its poor catalyst stability and susceptibility to deactivation, leading to high consumption of precious metal catalysts and increased production costs. Therefore, the industrially adopted technology is the furfural gas-phase decarbonylation process, which offers high furan yields and is a mature technology. Furfural gas-phase decarbonylation can be further divided into gas-phase oxidative decarbonylation and gas-phase reductive decarbonylation methods.

[0005] The furfural gas-phase oxidation decarbonylation method involves introducing a certain proportion of weakly oxidizing water vapor into a reactor to decarbonylate furfural and produce furan. Research and application of this method mainly occurred in the 1960s and 70s. It is a traditional production process involving oxide catalysts such as Zn-Cr, Zn-Cr-Mn, Zn-Cr-Fe, and Zn-Cd-Mn-Al. These catalysts have the advantages of low cost and high activity. However, their disadvantages include poor decarbonylation activity stability, low production capacity, and a decarbonylation reaction temperature exceeding 400℃. Such harsh process conditions easily cause furfural resinification, leading to a decrease in furan yield. Furthermore, the process requires a large amount of water vapor, resulting in chromium (cadmium)-containing wastewater that pollutes the environment. Therefore, this process has been abandoned by industry.

[0006] The furfural gas-phase reduction decarbonylation method involves introducing a certain proportion of reducing hydrogen into a reactor to produce furan and carbon monoxide from furfural. The catalysts used are primarily composed of noble metals as the active component. These catalysts exhibit high selectivity for decarbonylation and high furan yield, making them the mainstream technology for furan production. When using noble metals as catalysts, vaporized furfural is mixed with hydrogen and then fed into a continuous fixed-bed reactor. The resulting product, furan, undergoes a catalytic decarbonylation reaction. Unconverted furfural and the furan product are separated by condensation. The reaction tail gas mainly contains hydrogen and carbon monoxide in a ratio of approximately 1-5. After purification, this gas can be used for methanol synthesis.

[0007] Chinese patent document CN103084168A discloses a catalyst for the gas-phase reduction decarbonylation of furfural to produce furan. The catalyst's support is at least one selected from activated carbon, Al2O3, SiO2, ZnO, TiO2, V2O5, and SnO2. The main active component is Pd, and the co-active component is at least one selected from Ni, Co, Mg, Ca, Ba, Sn, Ge, Cr, rare earth elements, and alkali metals. The active component in this catalyst is prepared using a microemulsion method, which requires the use of large amounts of organic solvents such as isopropanol and cyclohexane. These volatile organic compounds pose safety hazards, leading to a complex catalyst preparation process, difficulty in mass production, and high costs. Furthermore, in the catalytic reaction of this technology, furfural easily forms oligomers such as furan resins, resulting in reduced catalyst activity and poor stability.

[0008] In recent years, rising palladium prices have limited the application of palladium catalysts in the large-scale gas-phase decarbonylation production of furfural. Therefore, there is an urgent need to develop novel catalysts for the decarbonylation of furfural to furan to improve catalyst activity and stability while reducing production costs. Summary of the Invention

[0009] Therefore, the technical problem to be solved by the present invention is to overcome the defects of low activity, poor stability and high production cost of furfural decarbonylation catalysts in the prior art, so as to provide a furfural decarbonylation catalyst with high activity, good stability and low production cost.

[0010] Another technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology of furfural decarbonylation catalyst preparation process being complex, difficult to mass-produce and costly, so as to provide a furfural decarbonylation catalyst preparation process that is simple, easy to mass-produce and low in cost.

[0011] The present invention also provides a method for preparing furan using the above-mentioned furfural decarbonylation catalyst. This method optimizes the process parameters for furfural gas-phase reduction decarbonylation to produce furan, enabling the catalyst to exert its best catalytic activity and good stability, thereby improving furfural conversion and furan selectivity, and thus increasing furan yield.

[0012] The objective of this invention is achieved through the following technical solution:

[0013] According to an embodiment of the present invention, in a first aspect, the present invention provides a furfural decarbonylation catalyst, comprising a support and an active component supported on the support; the active component is metals Pt and Co, and the support is an Al2O3-ZrO2-CeO2 composite oxide;

[0014] Based on the mass of the carrier, the Pt content is 0.2%-0.6%, the Co content is 4%-8%, the Al2O3 content is 74%-85%, the ZrO2 content is 11%-16%, and the CeO2 content is 4%-13%.

[0015] In some embodiments of the present invention, the furfural decarbonylation catalyst further includes an auxiliary agent K supported on the support, wherein the K content is 1%-3% based on the mass of the support.

[0016] In some embodiments of the present invention, the furfural decarbonylation catalyst, based on the mass of the support, has a Pt content of 0.3%-0.5%, a Co content of 5%-7%, a K content of 2%-3%, an Al2O3 content of 74%-79%, a ZrO2 content of 13%-14%, and a CeO2 content of 7%-13%.

[0017] In some embodiments of the present invention, the furfural decarbonylation catalyst, based on the mass of the support, has a Pt content of 0.4%, a Co content of 5%, a K content of 2%, an Al2O3 content of 79%, a ZrO2 content of 14%, and a CeO2 content of 7%.

[0018] According to an embodiment of the present invention, in a second aspect, the present invention also provides a process for preparing the furfural decarbonylation catalyst, comprising the following steps:

[0019] (1) Pseudoboehmite, zirconium hydroxide, and cerium hydroxide were ground, mixed evenly, and then suspended in dilute nitric acid. The mixture was then reacted at 80℃-90℃ for 15-20 hours, dried, and calcined to obtain an Al2O3-ZrO2-CeO2 composite oxide.

[0020] (2) The cobalt salt aqueous solution was slowly sprayed onto the composite oxide prepared in step (1), impregnated for a first time, dried, and calcined to obtain the Co / Al2O3-ZrO2-CeO2 catalyst intermediate;

[0021] (3) Prepare a mixed aqueous solution containing platinum source and potassium salt, place the Co / Al2O3-ZrO2-CeO2 catalyst intermediate obtained in step (2) into the mixed aqueous solution, impregnate for a second time, dry, calcine, and reduce to obtain Pt-Co-K / Al2O3-ZrO2-CeO2 catalyst.

[0022] In some embodiments of the present invention, the first time is 5 hours to 8 hours.

[0023] In some embodiments of the present invention, the second time is 5 to 8 hours.

[0024] In some embodiments of the present invention, in step (1), the calcination temperature is 720℃-750℃ and the calcination time is 5 hours-8 hours.

[0025] In some embodiments of the present invention, in step (2), the calcination temperature is 520℃-550℃ and the calcination time is 5 hours-8 hours.

[0026] In some embodiments of the present invention, in step (3), the calcination temperature is 520℃-550℃ and the calcination time is 5 hours-8 hours.

[0027] In some embodiments of the present invention, the reduction step in step (3) is to reduce with hydrogen at 300°C-320°C for 20-24 hours.

[0028] In some embodiments of the present invention, the cobalt salt is either cobalt nitrate or cobalt acetate.

[0029] In some embodiments of the present invention, the platinum source is either chloroplatinic acid or platinum nitrate.

[0030] In some embodiments of the present invention, the potassium salt is any one of potassium nitrate or potassium nitrate.

[0031] According to an embodiment of the present invention, in a third aspect, the present invention also provides a furan preparation process, comprising the following steps: furfural undergoes a decarbonylation reaction in the presence of a catalyst and hydrogen to obtain furan;

[0032] The catalyst is the furfural decarbonylation catalyst.

[0033] In some embodiments of the present invention, in the furan preparation process, the reaction temperature is 240℃-290℃, the hydrogen pressure is 0.03MPa-0.05MPa, and the furfural mass hourly space velocity is 0.1h. -1 -0.5h -1 The molar ratio of hydrogen to furfuryl alcohol is 3-5.

[0034] In some embodiments of the present invention, the reaction in the furan preparation process does not use a solvent.

[0035] In some embodiments of the present invention, in the furan preparation process, the reaction temperature is 260℃-270℃, the hydrogen pressure is 0.05MPa, and the furfural space velocity is 0.3h. -1 -0.4h-1 .

[0036] The technical solution of the present invention has the following advantages:

[0037] 1. The furfural decarbonylation catalyst provided by this invention includes a support and active components supported on the support, wherein the active components are metals Pt and Co, and the support is an Al2O3-ZrO2-CeO2 composite oxide. Based on the mass of the support, the Pt content is 0.2%-0.6%, the Co content is 4%-8%, the Al2O3 content is 74%-85%, the ZrO2 content is 11%-16%, and the CeO2 content is 4%-13%. This invention considers that the strongly acidic Al2O3 support easily leads to furfural polymerization and the formation of oligomers. Therefore, the Al2O3 support is modified with structural aids ZrO2 and CeO2 to obtain a composite oxide support with moderate acidity, which can avoid the oligomers formed by furfural polymerization from affecting the catalyst activity and stability. Using Co as an auxiliary active component can ensure catalytic effect while reducing the amount of the main active component Pt. This not only reduces the catalyst cost but, more importantly, improves the furfural conversion rate and furan selectivity in the furfural decarbonylation reaction, ensuring a high furan yield.

[0038] 2. The furfural decarbonylation catalyst provided by the present invention further includes an auxiliary agent K supported on a support, the content of which is 1%-3%. By adding the alkaline auxiliary agent K, the electronic state of the active metal surfaces of Pt and Co can be increased, the surface acidity and alkalinity can be improved, thereby increasing the furfural decarbonylation activity.

[0039] 3. The furfural decarbonylation catalyst provided by the present invention preferably has a Pt content of 0.3%-0.5%, a Co content of 5%-7%, a K content of 2%-3%, an Al2O3 content of 74%-79%, a ZrO2 content of 13%-14%, and a CeO2 content of 7%-13%; more preferably, it has a Pt content of 0.4%, a Co content of 5%, a K content of 2%, an Al2O3 content of 79%, a ZrO2 content of 14%, and a CeO2 content of 7%, which further improves the furfural conversion rate and furan selectivity in the furfural decarbonylation reaction, so that the furan yield can be as high as 99%.

[0040] 4. The preparation process of the furfural decarbonylation catalyst provided by the present invention, by first loading Co on the composite oxide support Al2O3-ZrO2-CeO2 and then simultaneously loading Pt and K, can mix Pt and K uniformly on the support surface, thereby improving the electronic state of the Pt active center and improving the overall performance of the catalyst.

[0041] 5. The preparation process of the furfural decarbonylation catalyst provided by the present invention can obtain the above-mentioned furfural decarbonylation catalyst by hydrogen reduction at 300°C for 20 hours. The reduction temperature is low, which can reduce the requirements for reactor material grade, thereby reducing equipment investment and saving investment.

[0042] 6. The furan preparation process provided by the present invention involves the decarbonylation reaction of furfural to produce furan in the presence of the above-mentioned furfural decarbonylation catalyst and hydrogen. The reaction conditions are mild, the catalyst lifetime is long, and the furan yield is high. Detailed Implementation

[0043] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0044] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0045] Because furfural contains numerous unsaturated double bonds, it is prone to polymerization during the reaction process. A decrease in hydrogen partial pressure or an increase in reaction temperature exacerbates this phenomenon. The polymerized furfural binds the catalyst together within the reactor, affecting its activity and lifespan. This invention, through extensive experimentation, has found that using the alkaline structural promoters ZrO2 and CeO2-modified composite oxide support Al2O3-ZrO2-CeO2 and its supported platinum-based catalyst can effectively inhibit furfural polymerization, ensuring catalyst activity and stability, and extending catalyst lifespan.

[0046] Catalyst Preparation Example 1

[0047] First, based on the oxide stoichiometry of the composite carrier Al2O3-ZrO2-CeO2, 109.8g of boehmite, 18.1g of zirconium hydroxide, and 9.7g of cerium hydroxide were mixed and ground evenly. After adding water to form a suspension, 20mL of a 40% (w / w) dilute nitric acid aqueous solution was added while stirring. The mixture was then subjected to a sol-gel reaction at 90℃ for 20 hours, dried at 110℃ for 12 hours, and calcined at 750℃ for 5 hours to obtain the aluminum-zirconium-cerium composite oxide.

[0048] The above-mentioned composite oxide support was added to a slowly rotating sugar coating machine. Then, a metered cobalt nitrate solution (containing 24.7 g of cobalt nitrate and 130 g of water) was slowly sprayed onto the composite oxide support. The support was impregnated for 5 hours, dried at 110°C for 12 hours, and finally calcined at 550°C for 5 hours. The resulting catalyst precursor was loaded into a reactor and reduced with hydrogen at 300-320°C to obtain a 5% Co / 78% Al2O3-14% ZrO2-8% CeO2 catalyst.

[0049] The content of active component Co is 5%, Al2O3 is 78%, ZrO2 is 14%, and CeO2 is 8%, with the mass of the composite oxide support as the denominator. The catalyst is labeled Cat1.

[0050] Catalyst Preparation Example 2

[0051] Cat1 was prepared using the same method as in Catalyst Preparation Example 1, and Pt was further loaded onto Cat1. The preparation method is as follows:

[0052] 100g of Cat1 was immersed in a metered chloroplatinic acid solution (containing 1.33g of chloroplatinic acid and 140g of water) for 5 hours, dried at 110℃ for 12 hours, and finally calcined at 550℃ for 5 hours. The resulting catalyst precursor was loaded into a reactor and reduced with hydrogen at 300-320℃ to obtain a 0.5%Pt-5%Co / 78%Al2O3-14%ZrO2-8%CeO2 catalyst.

[0053] The content of active components is calculated using the mass of the composite oxide support as the denominator: 0.5% Pt, 5% Co, 78% Al2O3, 14% ZrO2, and 8% CeO2. The catalyst is labeled Cat2.

[0054] Catalyst Preparation Example 3

[0055] The composite oxide support was prepared using the same method as in Catalyst Preparation Example 1. Pt and K were then further loaded onto the support. The preparation method is as follows: aluminum-zirconium-cerium composite oxide was obtained.

[0056] 1.33 g of chloroplatinic acid and 5.2 g of potassium nitrate were dissolved in 140 g of water to form a mixed aqueous solution. 100 g of aluminum zirconium cerium composite oxide support was immersed in the mixed aqueous solution for 5 hours, dried at 110 °C for 12 hours, and finally calcined at 550 °C for 5 hours. The resulting catalyst precursor was loaded into a reactor and reduced with hydrogen at 300-320 °C to obtain a 0.5% Pt-2% K / 78% Al2O3-14% ZrO2-8% CeO2 catalyst.

[0057] The content of active components is calculated using the mass of the composite oxide support as the denominator: 0.5% Pt, 2% K, 78% Al2O3, 14% ZrO2, and 8% CeO2. The catalyst is labeled Cat3.

[0058] Catalyst Preparation Example 4

[0059] Cat1 was prepared using the same method as in Catalyst Preparation Example 1, and Pt and K were further loaded onto Cat1. The preparation method is as follows:

[0060] 1.33 g of chloroplatinic acid and 5.2 g of potassium nitrate were dissolved in 140 g of water to form a mixed aqueous solution. 100 g of Cat1 was immersed in this mixed aqueous solution for 5 hours, dried at 110 °C for 12 hours, and finally calcined at 550 °C for 5 hours. The resulting catalyst precursor was loaded into a reactor and reduced with hydrogen at 300-320 °C to obtain a 0.5% Pt-5% Co-2% K / 78% Al2O3-14% ZrO2-8% CeO2 catalyst.

[0061] The content of active components is calculated using the mass of the composite oxide support as the denominator: 0.5% Pt, 5% Co, 2% K, 78% Al2O3, 14% ZrO2, and 8% CeO2. The catalyst is labeled Cat4.

[0062] Catalyst Preparation Example 5

[0063] First, according to the oxide stoichiometry of the composite oxide carrier Al2O3-ZrO2-CeO2, a certain amount of pseudoboehmite, zirconium hydroxide and cerium hydroxide are ground and mixed evenly, water is added to make a suspension, and dilute nitric acid solution is added while stirring. The mixture is subjected to a sol-gel reaction at 90℃ for 20 hours, then dried at 110℃ for 12 hours, and calcined at 750℃ for 5 hours to obtain the aluminum-zirconium-cerium composite oxide.

[0064] A composite oxide support was added to a slowly rotating coating machine, and then a metered cobalt nitrate solution was slowly sprayed onto the composite oxide support. The mixture was impregnated for 5 hours, dried at 110°C for 12 hours, and finally calcined at 550°C for 5 hours to obtain a Co / Al2O3-ZrO2-CeO2 catalyst intermediate.

[0065] 1.33 g of chloroplatinic acid and 2.6 g of potassium nitrate were dissolved in 140 g of water to form a mixed aqueous solution. 100 g of the Co / Al₂O₃-ZrO₂-CeO₂ catalyst intermediate was impregnated in this mixed aqueous solution for 5 hours, dried at 110 °C for 12 hours, and finally calcined at 550 °C for 5 hours. The resulting catalyst precursor was loaded into a reactor and subjected to hydrogen reduction at 300-320 °C to obtain 0.5% Pt-8% Co-1% K /

[0066] 83% Al2O3-11% ZrO2-6% CeO2 catalyst.

[0067] The content of active components is calculated using the mass of the composite oxide support as the denominator: 0.5% Pt, 8% Co, 1% K, 83% Al2O3, 11% ZrO2, and 6% CeO2. The catalyst is labeled Cat5.

[0068] Catalyst Preparation Example 6

[0069] First, according to the oxide carrier Al2O3-ZrO2-CeO2, a certain amount of pseudoboehmite, zirconium hydroxide and cerium hydroxide were ground and mixed evenly, and water was added to make a suspension. Then, dilute nitric acid solution was added while stirring, and the gelation reaction was carried out at 90°C for 20 hours. Then, it was dried at 110°C for 12 hours and calcined at 750°C for 5 hours to obtain aluminum zirconium cerium composite oxide.

[0070] Then, in a slowly rotating coating machine, a composite oxide support is added, and a metered cobalt nitrate solution is slowly sprayed onto the composite oxide support. The mixture is impregnated for 5 hours, dried at 110°C for 12 hours, and finally calcined at 550°C for 5 hours. The resulting catalyst precursor is then loaded into a reactor and reduced with hydrogen at 300-320°C to obtain the Co / Al₂O₃-ZrO₂-CeO₂ catalyst. Next, the Co / Al₂O₃-ZrO₂-CeO₂ catalyst prepared in the first step is impregnated with a metered solution of chloroplatinic acid and potassium nitrate for 5 hours, dried at 110°C for 12 hours, and finally calcined at 550°C for 5 hours to obtain an aluminum-zirconium-cerium composite oxide supported catalyst of 0.5% Pt-5% Co-2% K / 80% Al₂O₃-16% ZrO₂-4% CeO₂. Based on the composite support as the denominator: the active component Pt content is 0.5%, the Co content is 5%, and the K content is 2%. The catalyst is labeled Cat6.

[0071] Catalyst Preparation Example 7

[0072] First, according to the oxide carrier Al2O3-ZrO2-CeO2, a certain amount of pseudoboehmite, zirconium hydroxide and cerium hydroxide were ground and mixed evenly, and water was added to make a suspension. Then, dilute nitric acid solution was added while stirring, and the gelation reaction was carried out at 90°C for 20 hours. Then, it was dried at 110°C for 12 hours and calcined at 750°C for 5 hours to obtain aluminum zirconium cerium composite oxide.

[0073] Then, in a slowly rotating coating machine, a composite oxide support was added, and a metered cobalt nitrate solution was slowly sprayed onto the composite oxide support. The mixture was impregnated for 5 hours, dried at 110°C for 12 hours, and finally calcined at 550°C for 5 hours to obtain the Co / Al₂O₃-ZrO₂-CeO₂ catalyst. Next, the Co / Al₂O₃-ZrO₂-CeO₂ catalyst prepared in the first step was impregnated with a metered solution of chloroplatinic acid and potassium nitrate for 5 hours, dried at 110°C for 12 hours, and finally calcined at 550°C for 5 hours. The resulting catalyst precursor was loaded into a reactor and subjected to hydrogen reduction at 300-320°C to obtain an aluminum-zirconium-cerium composite oxide supported 0.5% Pt-5% Co-3% K / 74% Al₂O₃-13% ZrO₂-13% CeO₂ catalyst. Based on the composite support as the denominator: the active component Pt content is 0.5%, the Co content is 5%, and the K content is 3%. The catalyst is labeled Cat7.

[0074] Catalyst Preparation Example 8

[0075] First, according to the oxide carrier Al2O3-ZrO2-CeO2, a certain amount of pseudoboehmite, zirconium hydroxide and cerium hydroxide were ground and mixed evenly, and water was added to make a suspension. Then, dilute nitric acid solution was added while stirring, and the gelation reaction was carried out at 90°C for 20 hours. Then, it was dried at 110°C for 12 hours and calcined at 750°C for 5 hours to obtain aluminum zirconium cerium composite oxide.

[0076] Then, in a slowly rotating coating machine, a composite oxide support was added, and a metered cobalt nitrate solution was slowly sprayed onto the composite oxide support. The mixture was impregnated for 5 hours, dried at 110°C for 12 hours, and finally calcined at 550°C for 5 hours to obtain the Co / Al₂O₃-ZrO₂-CeO₂ catalyst. Next, the Co / Al₂O₃-ZrO₂-CeO₂ catalyst prepared in the first step was impregnated with a metered solution of chloroplatinic acid and potassium nitrate for 5 hours, dried at 110°C for 12 hours, and finally calcined at 550°C for 5 hours. The resulting catalyst precursor was loaded into a reactor and subjected to hydrogen reduction at 300-320°C to obtain an aluminum-zirconium-cerium composite oxide supported catalyst of 0.2% Pt-5% Co-2% K / 79% Al₂O₃-14% ZrO₂-7% CeO₂. Based on the composite support as the denominator: the active component Pt content is 0.2%, the Co content is 5%, and the K content is 2%. The catalyst is labeled Cat8.

[0077] Catalyst Preparation Example 9

[0078] First, according to the oxide carrier Al2O3-ZrO2-CeO2, a certain amount of pseudoboehmite, zirconium hydroxide and cerium hydroxide were ground and mixed evenly, and water was added to make a suspension. Then, dilute nitric acid solution was added while stirring, and the gelation reaction was carried out at 90°C for 20 hours. Then, it was dried at 110°C for 12 hours and calcined at 750°C for 5 hours to obtain aluminum zirconium cerium composite oxide.

[0079] Then, in a slowly rotating coating machine, a composite oxide support was added, and a metered cobalt nitrate solution was slowly sprayed onto the composite oxide support. The mixture was impregnated for 5 hours, dried at 110°C for 12 hours, and finally calcined at 550°C for 5 hours to obtain the Co / Al₂O₃-ZrO₂-CeO₂ catalyst. Next, the Co / Al₂O₃-ZrO₂-CeO₂ catalyst prepared in the first step was impregnated with a metered solution of chloroplatinic acid and potassium nitrate for 5 hours, dried at 110°C for 12 hours, and finally calcined at 550°C for 5 hours. The resulting catalyst precursor was loaded into a reactor and reduced with hydrogen at 300-320°C to obtain an aluminum-zirconium-cerium composite oxide supported catalyst of 0.3% Pt-5% Co-2% K / 79% Al₂O₃-14% ZrO₂-7% CeO₂. Based on the composite support as the denominator: the active component Pt content is 0.3%, the Co content is 5%, and the K content is 2%. The catalyst is labeled Cat9.

[0080] Catalyst Preparation Example 10

[0081] First, according to the oxide carrier Al2O3-ZrO2-CeO2, a certain amount of pseudoboehmite, zirconium hydroxide and cerium hydroxide were ground and mixed evenly, and water was added to make a suspension. Then, dilute nitric acid solution was added while stirring, and the gelation reaction was carried out at 90°C for 20 hours. Then, it was dried at 110°C for 12 hours and calcined at 750°C for 5 hours to obtain aluminum zirconium cerium composite oxide.

[0082] Then, in a slowly rotating coating machine, a composite oxide support was added, and a metered cobalt nitrate solution was slowly sprayed onto the composite oxide support. The mixture was impregnated for 5 hours, dried at 110°C for 12 hours, and finally calcined at 550°C for 5 hours to obtain the Co / Al₂O₃-ZrO₂-CeO₂ catalyst. Next, the Co / Al₂O₃-ZrO₂-CeO₂ catalyst prepared in the first step was impregnated with metered chloroplatinic acid and potassium nitrate solutions for 5 hours, dried at 110°C for 12 hours, and finally calcined at 550°C for 5 hours. The resulting catalyst precursor was loaded into a reactor and subjected to hydrogen reduction at 300-320°C to obtain an aluminum-zirconium-cerium composite oxide supported catalyst of 0.4% Pt-5% Co-2% K / 79% Al₂O₃-14% ZrO₂-7% CeO₂.

[0083] Based on the composite support as the denominator: the active component Pt content is 0.4%, the Co content is 5%, and the K content is 2%. The catalyst is labeled Cat10.

[0084] Catalyst Preparation Example 11

[0085] Using the same method as in Catalyst Preparation Example 10, Co was first loaded onto the Al2O3 support, followed by simultaneous loading of Pt and K, to obtain 0.4%Pt-5%Co-2%K / Al2O3.

[0086] Using the mass of the support Al2O3 as the denominator: the active component Pt content is 0.4%, the Co content is 5%, and the K content is 2%. The catalyst is labeled Cat11.

[0087] Catalyst Preparation Example 12

[0088] The aluminum-zirconium composite carrier Al2O3-ZrO2 was prepared by grinding and mixing 111g of boehmite and 27g of zirconium hydroxide evenly according to the oxide stoichiometry. After adding water to make a suspension, 20mL of dilute nitric acid aqueous solution with a mass percentage of 40% was added while stirring. The mixture was subjected to a sol-gel reaction at 90℃ for 20 hours, then dried at 110℃ for 12 hours, and calcined at 750℃ for 5 hours to obtain the aluminum-zirconium composite carrier.

[0089] Using the same method as in Catalyst Preparation Example 10, Co was first loaded onto an aluminum-zirconium composite support, followed by simultaneous loading of Pt and K, to obtain a 0.4%Pt-5%Co-2%K / 79%Al2O3-21%ZrO2 catalyst.

[0090] Using the mass of the support Al2O3 as the denominator: the active components Pt content is 0.4%, Co content is 5%, K content is 2%, Al2O3 content is 79%, and ZrO2 content is 21%. The catalyst is labeled Cat12.

[0091] Catalyst Preparation Example 13

[0092] The aluminum-cerium composite carrier Al2O3-CeO2 was prepared by grinding and mixing 111g of boehmite and 25.4g of cerium hydroxide evenly according to the oxide stoichiometry. After adding water to make a suspension, 20mL of dilute nitric acid aqueous solution with a mass percentage of 40% was added while stirring. The mixture was subjected to a sol-gel reaction at 90℃ for 20 hours, then dried at 110℃ for 12 hours, and calcined at 750℃ for 5 hours to obtain the aluminum-cerium composite carrier.

[0093] Using the same method as in Catalyst Preparation Example 10, Co was first loaded onto an aluminum-cerium composite support, followed by simultaneous loading of Pt and K, to obtain a 0.4%Pt-5%Co-2%K / 79%Al2O3-21%CeO2 catalyst.

[0094] Using the mass of the support Al2O3 as the denominator: the active components Pt content is 0.4%, Co content is 5%, K content is 2%, Al2O3 content is 79%, and CeO2 content is 21%. The catalyst is labeled Cat13.

[0095] Catalyst Preparation Example 14

[0096] The aluminum-titanium composite carrier Al2O3-TiO2 was prepared by grinding and mixing 111g of boehmite and 30.5g of titanium hydroxide evenly according to the oxide stoichiometry. After adding water to make a suspension, 20mL of dilute nitric acid aqueous solution with a mass percentage of 40% was added while stirring. The mixture was subjected to a sol-gel reaction at 90℃ for 20 hours, then dried at 110℃ for 12 hours, and calcined at 750℃ for 5 hours to obtain the aluminum-titanium composite carrier.

[0097] Using the same method as in Catalyst Preparation Example 10, Co was first loaded onto an aluminum-titanium composite support, followed by simultaneous loading of Pt and K, to obtain a 0.4%Pt-5%Co-2%K / 79%Al2O3-21%TiO2 catalyst.

[0098] Using the mass of the support Al2O3 as the denominator: the active components Pt content is 0.4%, Co content is 5%, K content is 2%, Al2O3 content is 79%, and TiO2 content is 21%. The catalyst is labeled Cat14.

[0099] Example 1 of furan preparation

[0100] Reaction conditions: 50g of the catalyst prepared above was packed into a fixed-bed reactor, and hydrogen reduction was first carried out at 300℃ for 20 hours; the hydrogen pressure in the reactor was controlled at 0.05MPa, the reaction temperature at 260℃, and the furfural space velocity at 0.3h. -1 The reaction was carried out with a hydrogen / furfuryl alcohol molar ratio of 3.

[0101] The product distribution was quantitatively analyzed by gas chromatography. The furfural decarbonylation conversion rate and furan selectivity are shown in Table 1. Other major byproducts were tetrahydrofuran, furfuryl alcohol, 2-methylfuran, and n-pentanol. Taking Cat10 as an example, the product distribution was: furan 99.2%, tetrahydrofuran 0.5%, 2-methylfuran 0.2%, and furfuryl alcohol 0.1%.

[0102] Table 1. Effects of different catalysts on the gas-phase reduction decarbonylation reaction of furfural to furan.

[0103]

[0104]

[0105] As shown in Table 1, Cat10 exhibits the best furan yield. Therefore, 50 g of Cat10 was refilled into a fixed-bed reactor, and the reactor was first reduced with hydrogen at 300 °C for 20 hours. Then, under the conditions of a hydrogen pressure of 0.05 MPa and a hydrogen / furfural molar ratio of 3–5, the effects of reaction temperature and liquid hourly space velocity on the furfural decarbonylation conversion and furan selectivity were investigated. The results are shown in Table 2.

[0106] Table 2. Effects of reaction temperature and space velocity on furfural decarbonylation conversion and furan selectivity.

[0107]

[0108] As can be seen from Table 2, the reaction conditions were as follows: reaction temperature 260–270℃, pressure 0.05 MPa, and furfural space velocity 0.3–0.4 h⁻¹. -1 Under the condition of hydrogen / furfural molar ratio of 4, furfural decarbonylation conversion and furan selectivity are the highest.

[0109] The experimental data above show that in the Pt-Co-K / Al2O3-ZrO2-CeO2 catalyst system, the catalyst composition of 0.4% Pt-5% Co-2% K / 79% Al2O3-14% ZrO2-7% CeO2, at a reaction temperature of 260–270℃, a pressure of 0.05 MPa, and a furfural space velocity of 0.3–0.4 h⁻¹, is optimal. -1 Under conditions of a hydrogen / furfural molar ratio of 3 to 5, furan can be prepared with high selectivity by decarbonylation of furfural, with a yield of up to 99%.

[0110] In summary, this invention, by employing a platinum-based catalyst supported on a composite oxide carrier, can achieve a reaction at a hydrogen pressure of 0.05 MPa, a reaction temperature of 260–270 °C, and a furfural space velocity of 0.3–0.4 h⁻¹. -1 The directed catalytic conversion of furfural is achieved under conditions of a hydrogen / furfural molar ratio of 3–5. This method can be used in continuous fixed-bed reactors and other similar devices to achieve highly efficient catalytic conversion and decarbonylation of furfural. The catalyst is stable, yields high furan, and is simple to process, making it valuable for industrial production.

[0111] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A furfural decarbonylation catalyst, comprising a support and an active component supported on the support; characterized in that, The active components are metals Pt and Co, and the support is an Al2O3-ZrO2-CeO2 composite oxide; Based on the mass of the carrier, the Pt content is 0.3%-0.5%, the Co content is 5%-7%, the Al2O3 content is 74%-79%, the ZrO2 content is 13%-14%, and the CeO2 content is 7%-13%. The furfural decarbonylation catalyst further includes an auxiliary agent K supported on the support, wherein the K content is 2%-3% based on the mass of the support; The preparation method of the furfural decarbonylation catalyst includes the following steps: (1) Pseudoboehmite, zirconium hydroxide and cerium hydroxide are ground, mixed evenly, and then dilute nitric acid is added to adjust to a suspension state. The mixture is then reacted at 80℃-90℃ for 15-20 hours, dried and calcined to obtain Al2O3-ZrO2-CeO2 composite oxide. (2) The cobalt salt aqueous solution is slowly sprayed onto the composite oxide prepared in step (1), impregnated for a first time, dried, and calcined to obtain the Co / Al2O3-ZrO2-CeO2 catalyst intermediate; (3) Prepare a mixed aqueous solution containing platinum source and potassium salt, place the Co / Al2O3-ZrO2-CeO2 catalyst intermediate obtained in step (2) into the mixed aqueous solution, impregnate for a second time, dry, calcine, and reduce to obtain Pt-Co-K / Al2O3-ZrO2-CeO2 catalyst.

2. The furfural decarbonylation catalyst according to claim 1, characterized in that, Based on the mass of the carrier, the Pt content is 0.4%, the Co content is 5%, the K content is 2%, the Al2O3 content is 79%, the ZrO2 content is 14%, and the CeO2 content is 7%.

3. A preparation process for the furfural decarbonylation catalyst according to any one of claims 1-2, characterized in that, Includes the following steps: (1) Pseudoboehmite, zirconium hydroxide and cerium hydroxide are ground, mixed evenly, and then dilute nitric acid is added to adjust to a suspension state. The mixture is then reacted at 80℃-90℃ for 15-20 hours, dried and calcined to obtain Al2O3-ZrO2-CeO2 composite oxide. (2) The cobalt salt aqueous solution is slowly sprayed onto the composite oxide prepared in step (1), impregnated for a first time, dried, and calcined to obtain the Co / Al2O3-ZrO2-CeO2 catalyst intermediate; (3) Prepare a mixed aqueous solution containing platinum source and potassium salt, place the Co / Al2O3-ZrO2-CeO2 catalyst intermediate obtained in step (2) into the mixed aqueous solution, impregnate for a second time, dry, calcine, and reduce to obtain Pt-Co-K / Al2O3-ZrO2-CeO2 catalyst.

4. The preparation process of the furfural decarbonylation catalyst according to claim 3, characterized in that, The first timeframe is 5-8 hours; and / or, The second timeframe is 5-8 hours; and / or, In step (1), the roasting temperature is 720℃-750℃, and the roasting time is 5 hours-8 hours; and / or, In step (2), the calcination temperature is 520℃-550℃, and the calcination time is 5 hours-8 hours; and / or, In step (3), the calcination temperature is 520℃-550℃, and the calcination time is 5 hours-8 hours; and / or, The reduction step in step (3) involves reducing hydrogen at 300℃-320℃ for 20-24 hours.

5. The preparation process of the furfural decarbonylation catalyst according to claim 3, characterized in that, The cobalt salt is either cobalt nitrate or cobalt acetate; and / or, The platinum source is either chloroplatinic acid or platinum nitrate; and / or, The potassium salt is either potassium nitrate or potassium nitrate.

6. A process for preparing furan, characterized in that, The process includes the following steps: furfural undergoes a decarbonylation reaction in the presence of a catalyst and hydrogen to produce furan; The catalyst is the furfural decarbonylation catalyst according to any one of claims 1-2.

7. The furan preparation process according to claim 6, characterized in that, The reaction temperature was 240℃-290℃, the hydrogen pressure was 0.03MPa-0.05MPa, and the furfural mass hourly space velocity was 0.1h. -1 -0.5h -1 The molar ratio of hydrogen to furfuryl alcohol is 3-5; and / or, the reaction does not use a solvent.

8. The furan preparation process according to claim 7, characterized in that, The reaction temperature was 260℃-270℃, the hydrogen pressure was 0.05MPa, and the furfural space velocity was 0.3h. -1 -0.4h -1 .

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