Ru-m@al-sio2 catalyst, and preparation method and application thereof
By preparing a core-shell structured Ru-M@Al-SiO2 catalyst, the problems of large amounts of precious metals and short lifespan of existing catalysts were solved, achieving a highly efficient hydrogenation reaction of pyromellitic esters, reducing production costs and improving the recyclability of the catalyst.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2023-10-08
- Publication Date
- 2026-07-07
AI Technical Summary
Existing catalysts require large amounts of precious metals in the hydrogenation of pyromellitic esters to prepare hydrogenated pyromellitic esters, resulting in high production costs and short catalyst lifespans, making it difficult to meet industrial-scale requirements.
A core-shell structured Ru-M@Al-SiO2 catalyst is prepared by combining Ru as the active component and M as the co-active component with an Al-SiO2 support. The preparation method includes mixing a solution of a template agent, the active component, and the co-active component, heating and stirring, and adding a silicon source and an aluminum source dropwise to form a microsphere catalyst.
It improves the activity and selectivity of the catalyst, reduces the loading of precious metals, simplifies the preparation process, enhances the recyclability of the catalyst, reduces production costs, and is beneficial for industrial production.
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Figure CN119771403B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst preparation technology, specifically relating to a Ru-M@Al-SiO2 catalyst and its preparation method, as well as its application in the catalytic synthesis of hydrogenated tetramethyl pyromellitic acid from tetramethyl pyromellitic acid. Background Technology
[0002] Hydrogenated pyromellitic dianhydride is an important organic synthesis intermediate, and also an intermediate for the development of new chemical materials and high-value-added fine chemical products. It is mainly used in laboratory research and development processes and chemical production. Currently, the main application of hydrogenated pyromellitic dianhydride both domestically and internationally is in the production of polyimide (PI), a novel engineering plastic. Colorless and transparent polyimide (PI), prepared by reacting hydrogenated pyromellitic dianhydride with aromatic diamine compounds such as p-diaminodiphenyl ether, possesses excellent transparency and infusibility. It can be made into films, fibers, enameled wire coatings, adhesives, laminates, and molded parts, and is known as "gold film." It has broad application prospects in high-tech fields such as microelectronics, automobiles, optoelectronics, large-scale integrated circuits, flat panel displays, aerospace, and semiconductor materials. For example, in the field of optics, it is used as optical switching material, passive or active waveguide material, optical fiber, second-order nonlinear optical material, optoelectronic packaging material, photosensitive material, filter, photorefractive material and other related optoelectronic materials; in the field of electronics, it is used as substrate material for organic light-emitting diode (OLED) displays, substrate material for liquid crystal displays, negative compensation film, liquid crystal alignment film material, etc.; in the aerospace field, it is used as thermal control coating material, antenna collector material, antenna reflector material, interlayer insulating film of solar panel, etc.
[0003] The key technology for preparing hydrogenated pyromellitic dianhydride is the preparation of hydrogenated pyromellitic acid. Hydrogenated pyromellitic acid is mainly obtained by catalytic hydrogenation of pyromellitic acid; or by hydrogenation of pyromellitic ester to synthesize hydrogenated pyromellitic ester, followed by hydrolysis to obtain hydrogenated pyromellitic acid. Both of these methods fall under the category of hydrogenation of aromatic compounds and saturated hydrogenation of benzene rings.
[0004] EP1323700 uses pyromellitic acid as raw material and hydrogenation is carried out in a batch reactor with 5% Rh / C catalyst. The catalyst has high initial activity and selectivity, but the reusability of the catalyst is low and it must be activated frequently, which greatly increases the production cost.
[0005] JP2006083080 and JP200863263 also use rhodium as the active component, but the catalyst has a short lifespan.
[0006] CN102105428 uses a mixed catalyst of palladium and rhodium to catalyze the hydrogenation of pyromellitic acid, but its reaction conditions are harsh, requiring a hydrogen pressure of at least 8 MPa, which places high demands on the reaction equipment and requires a large investment in equipment for industrialization.
[0007] CN104926649 uses Ru-Pd noble metal as the active component and Ce as an auxiliary agent supported on activated carbon. This catalyst can effectively reduce the reaction pressure, but the reaction temperature is high and the amount of catalyst used is large, resulting in excessive initial investment costs.
[0008] Based on existing technologies, the synthesis of hydrogenated tetramethyl pyromellitic acid by hydrogenation of tetramethyl pyromellitic acid and subsequent hydrolysis yields higher yields. However, current catalysts use noble metals such as Rh, Pd, Pt, and Ru as active components, and the amount of catalyst used is relatively large, which is not conducive to industrial production.
[0009] Therefore, while ensuring catalytic activity, introducing non-precious metal promoters to reduce the amount of precious metals is the future research direction for the hydrogenation reaction of tetramethyl pyromellitic acid. Summary of the Invention
[0010] Purpose of the invention: The purpose of this invention is to address the shortcomings of existing technologies by providing a core-shell structure Ru-M@
[0011] Al-SiO2 catalyst, its preparation method, and its application. This invention provides a catalyst for the catalytic hydrogenation of pyromellitic ester to hydrogenated pyromellitic ester, exhibiting high conversion of the substrate pyromellitic ester and high selectivity for the target product, hydrogenated pyromellitic ester.
[0012] Technical solution: The objective of this invention is achieved through the following technical solution:
[0013] This invention provides a core-shell structured Ru-M@Al-SiO2 catalyst, which is composed of an active component Ru, a co-active component M, and an Al-SiO2 support; the active component Ru and the co-active component M form the core layer, and the Al-SiO2 support forms the shell; the catalyst has a microsphere morphology.
[0014] The mass ratio of Al-SiO2 support to active component Ru is 1:0.02-0.05; the mass ratio of Al-SiO2 support to co-active component M is 1:0.01-0.025.
[0015] Preferably, the auxiliary active component M is one of the transition metals W, Ni, Co, and Ce.
[0016] This invention also provides a method for preparing the above-mentioned core-shell structure Ru-M@Al-SiO2 catalyst, comprising the following steps:
[0017] (1) Weigh the template agent CTABr into distilled water, add PVP solution, and heat and stir for 0.5 to 2 hours;
[0018] (2) Add Ru(NH3)6Cl3 solution and M metal salt solution.
[0019] (3) Add ascorbic acid solution and sodium hydroxide solution, keep heating and stirring for 0.5 to 2 hours, and add TEOS dropwise;
[0020] (4) Add sodium aluminate solution, keep heating and stirring for 0.5 to 2 hours. After the reaction is complete, centrifuge, filter, wash, dry and calcinate to reduce and obtain Ru-M@Al-SiO2 catalyst.
[0021] Preferably, in step (2), the M metal salt is H. 28 N6O 41 W 12 Any one of Ni(NO3)2·6H2O, Co(NO3)2·6H2O or Ce(NO3)2·6H2O.
[0022] Preferably, in step (1), the concentration of CTABr is 0.005-0.01 g / mL, and the concentration of PVP solution is 0.01-0.02 g / mL; in step (3), the concentration of ascorbic acid solution is 0.1-0.2 g / mL, and the concentration of sodium hydroxide solution is 0.05-0.1 g / mL; in step (4), the concentration of sodium aluminate solution is 0.01-0.02 g / mL.
[0023] Preferably, the mass ratio of TEOS to CTABr is 1:0.2-0.3; the mass ratio of TEOS to PVP is 1:0.02-0.03; the mass ratio of TEOS to Ru(NH3)6Cl3 is 1:0.002-0.005; the mass ratio of TEOS to M metal salt is 1:0.0042-0.0387; the mass ratio of TEOS to ascorbic acid is 1:0.1-0.15; the mass ratio of TEOS to sodium hydroxide is 1:0.1-0.15; and the mass ratio of TEOS to sodium aluminate is 1:0.04.
[0024] Preferably, the heating and stirring temperature is 80-90℃ and the stirring speed is 80-100 rpm / min.
[0025] This invention also provides the application of the above-mentioned core-shell structure Ru-M@Al-SiO2 catalyst in the catalytic synthesis of hydrogenated tetramethyl pyromellitic acid from tetramethyl pyromellitic acid.
[0026] The specific steps for synthesizing hydrogenated tetramethyl pyromellitic acid from catalytic tetramethyl pyromellitic acid are as follows: the Ru-M@Al-SiO2 catalyst, tetramethyl pyromellitic acid, and solvent are added sequentially to the reaction vessel. After replacing the air in the vessel with hydrogen, the vessel is pressurized and heated to the reaction temperature to start the reaction. After the reaction is completed, the catalyst is separated by centrifugation.
[0027] Preferably, the mass ratio of tetramethyl pyromellitic acid to Ru-M@Al-SiO2 catalyst is 1:0.03-0.05; the mass-volume ratio of tetramethyl pyromellitic acid to solvent is 1:20-30; the reaction temperature is 80-100℃, the hydrogen pressure is 4-6 MPa, and the reaction time is 4-6 h.
[0028] Preferably, the solvent is selected from one or more of methanol, ethanol, isopropanol or DMF.
[0029] Beneficial effects:
[0030] (1) The Ru-M@Al-SiO2 catalyst provided by this invention has the advantages of high activity and easy catalyst separation. This catalyst is a noble metal catalyst, and compared with existing noble metal catalysts, it has a lower noble metal loading, which reduces production costs and is more conducive to industrial production.
[0031] (2) The preparation method of Ru-M@Al-SiO2 catalyst provided by the present invention is simple, convenient to operate, and mild. The core-shell structure enhances the recyclability of the catalyst. The process is environmentally friendly and conducive to large-scale production.
[0032] (3) The Ru-M@Al-SiO2 catalyst provided by the present invention is used to catalyze the synthesis of hydrogenated tetramethyl pyromellitic acid from tetramethyl pyromellitic acid, and has high conversion rate and selectivity. Attached Figure Description
[0033] Figure 1 Figure 1 shows the TEM and SEM images of the Ru-W@Al-SiO2-1 catalyst in Example 1, where Figure (a) is the TEM image of Ru-W@Al-SiO2-1 and Figure (b) is the SEM image of Ru-W@Al-SiO2-1.
[0034] Figure 2 The figure shows the results of the catalyst stability evaluation. Detailed Implementation
[0035] The technical solution of the present invention will be described in detail below through specific embodiments, but the scope of protection of the present invention is not limited to the embodiments described.
[0036] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.
[0037] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the experimental materials used in the following examples are commercially available products.
[0038] Example 1
[0039] First, weigh 0.25 g of the template agent hexadecyltrimethylammonium bromide (CTABr) and dissolve it in distilled water to prepare an aqueous solution with a concentration of C(CTABr) = 0.0075 g / mL. Stir at room temperature until the solution is clear and transparent. Add 2.5 mL of 0.01 g / mL PVP-K60 solution to the above solution, heat to 90 °C, and stir for 0.5 h. Then add 0.0030 g of Ru(NH3)6Cl3 and 0.0042 g of H2O. 28 N6O 41 W 12 The above solution was stirred for 0.5 h. 1 mL of 0.1 g / mL ascorbic acid solution was added, and the mixture was heated and stirred at 80 rpm / min for 0.5 h. Then, 2 mL of 0.05 g / mL sodium hydroxide solution was added, and the mixture was heated and stirred for 0.5 h. 1 g of tetraethyl orthosilicate (TEOS) was added dropwise, and the mixture was stirred for 0.5 h. Then, 4 mL of 0.01 g / mL sodium aluminate solution was added, and the mixture was heated and stirred for 2 h. The resulting product was centrifuged, filtered, washed, and dried. The dried sample was calcined in a muffle furnace at 550 °C for 3 h (heating rate of 2 °C / min), and then reduced in a muffle furnace at 400 °C for 2 h in an H2 / Ar mixed gas with a hydrogen integral of 10%, to obtain the Ru-W@Al-SiO2 catalyst, denoted as Ru-W@Al-SiO2-1.
[0040] The mass ratio of Al-SiO2 to active component Ru is 1:0.03, and the mass ratio of Al-SiO2 to co-active component W is 1:0.01.
[0041] Figure 1 The images show TEM and SEM images of the Ru-W@Al-SiO2-1 catalyst. As can be seen from the images, the catalyst has a microsphere morphology with an average particle size of 0.8 μm.
[0042] Example 2
[0043] First, dissolve 0.2 g of the template agent CTABr in distilled water to prepare an aqueous solution with a concentration of C(CTABr) = 0.005 g / mL. Stir at room temperature until the solution is clear and transparent. Add 2 mL of 0.01 g / mL PVP-K60 solution to the above solution, heat to 85°C, and stir for 0.5 h. Then add 0.0050 g of Ru(NH3)6Cl3 and 0.0105 g of H2O. 28 N6O 41 W 12 The solution was stirred for 0.5 h. 1 mL of 0.15 g / mL ascorbic acid solution was added, and the mixture was heated and stirred at 100 rpm / min for 0.5 h. Then, 1.5 mL of 0.1 g / mL sodium hydroxide solution was added, and the mixture was heated and stirred for 10 min. 1 g of TEOS was added dropwise, and the mixture was stirred for 0.5 h. Then, 2 mL of 0.02 g / mL sodium aluminate solution was added, and the mixture was heated and stirred for 1 h. The resulting product was centrifuged, filtered, washed, and dried. The dried sample was calcined in a muffle furnace at 550 °C for 3 h (heating rate of 2 °C / min), and then reduced in a muffle furnace at 400 °C for 2 h in an H2 / Ar mixed gas with a hydrogen integral of 10%, to obtain the Ru-W@Al-SiO2 catalyst, denoted as Ru-W@Al-SiO2-2.
[0044] The mass ratio of Al-SiO2 to active component Ru is 1:0.05, and the mass ratio of Al-SiO2 to co-active component W is 1:0.025.
[0045] Example 3
[0046] First, dissolve 0.3 g of the template agent CTABr in distilled water to prepare an aqueous solution with a concentration of C(CTABr) = 0.01 g / mL. Stir at room temperature until the solution is clear and transparent. Add 1.5 mL of 0.02 g / mL PVP-K60 solution to the above solution, heat to 80 °C, and stir for 0.5 h. Then add 0.0040 g of Ru(NH3)6Cl3 and 0.0387 g of Ni(NO3)2·6H2O to the above solution and stir for 0.5 h. Add 1 mL of 0.15 g / mL ascorbic acid solution and heat and stir at 90 rpm / min for 0.5 h. Then add 1.5 mL of 0.1 g / mL sodium hydroxide solution and heat and stir for 0.5 h. Add 1 g of TEOS dropwise and stir for 0.5 h, then add 4 mL of 0.01 g / mL sodium aluminate solution and heat and stir for 1.5 h. The obtained product was centrifuged, filtered, washed, and dried. The dried sample was then calcined in a muffle furnace at 550℃ for 3 hours (heating rate of 2℃ / min). Subsequently, it was placed in a muffle furnace and reduced at 400℃ for 2 hours in an H2 / Ar mixed gas with a hydrogen integral of 10%, to obtain the Ru-Ni@Al-SiO2 catalyst, denoted as Ru-Ni@Al-SiO2-1.
[0047] The mass ratio of Al-SiO2 to the active component Ru is 1:0.04, and the mass ratio of Al-SiO2 to the co-active component Ni is 1:0.025.
[0048] Example 4
[0049] First, dissolve 0.2 g of the template agent CTABr in distilled water to prepare an aqueous solution with a concentration of C(CTABr) = 0.005 g / mL. Stir at room temperature until the solution is clear and transparent. Add 2 mL of 0.01 g / mL PVP-K60 solution to the above solution, heat to 90 °C, and stir for 0.5 h. Then add 0.0030 g of Ru(NH3)6Cl3 and 0.0232 g of Ni(NO3)2·6H2O to the above solution and stir for 0.5 h. Add 0.5 mL of 0.2 g / mL ascorbic acid solution and heat and stir at 90 rpm / min for 0.5 h. Then add 2.5 mL of 0.05 g / mL sodium hydroxide solution and heat and stir for 0.5 h. Add 1 g of TEOS dropwise and stir for 0.5 h, then add 2 mL of 0.02 g / mL sodium aluminate solution and heat and stir for 1 h. The obtained product was centrifuged, filtered, washed, and dried. The dried sample was then calcined in a muffle furnace at 550℃ for 3 hours (heating rate of 2℃ / min). Subsequently, it was placed in a muffle furnace and reduced at 400℃ for 2 hours in an H2 / Ar mixed gas with a hydrogen integral of 10%, to obtain the Ru-Ni@Al-SiO2 catalyst, denoted as Ru-Ni@Al-SiO2-2.
[0050] The mass ratio of Al-SiO2 to the active component Ru is 1:0.03, and the mass ratio of Al-SiO2 to the co-active component Ni is 1:0.015.
[0051] Example 5
[0052] First, dissolve 0.25 g of the template agent CTABr in distilled water to prepare an aqueous solution with a concentration of C(CTABr) = 0.0075 g / mL. Stir at room temperature until the solution is clear and transparent. Add 2.5 mL of 0.01 g / mL PVP-K60 solution to the above solution, heat to 80 °C, and stir for 0.5 h. Then add 0.0020 g of Ru(NH3)6Cl3 and 0.0154 g of Co(NO3)2·6H2O to the above solution and stir for 15 min. Add 1 mL of 0.1 g / mL ascorbic acid solution and heat and stir at 100 rpm for 0.5 h. Then add 2 mL of 0.05 g / mL sodium hydroxide solution and heat and stir for 0.5 h. Add 1 g of TEOS dropwise and stir for 0.5 h, then add 4 mL of 0.01 g / mL sodium aluminate solution and heat and stir for 2 h. The obtained product was centrifuged, filtered, washed, and dried. The dried sample was then calcined in a muffle furnace at 550℃ for 3 hours (heating rate of 2℃ / min). Subsequently, it was placed in a muffle furnace and reduced at 400℃ for 2 hours in an H2 / Ar mixed gas with a hydrogen integral of 10%, to obtain the Ru-Co@Al-SiO2 catalyst, denoted as Ru-Co@Al-SiO2-1.
[0053] The mass ratio of Al-SiO2 to the active component Ru is 1:0.02, and the mass ratio of Al-SiO2 to the co-active component Co is 1:0.01.
[0054] Example 6
[0055] First, dissolve 0.3 g of the template agent CTABr in distilled water to prepare an aqueous solution with a concentration of C(CTABr) = 0.01 g / mL. Stir at room temperature until the solution is clear and transparent. Add 1.5 mL of 0.02 g / mL PVP-K60 solution to the above solution, heat to 90 °C, and stir for 0.5 h. Then add 0.0040 g of Ru(NH3)6Cl3 and 0.0309 g of Co(NO3)2·6H2O to the above solution and stir for 1 h. Add 1 mL of 0.15 g / mL ascorbic acid solution and heat and stir at 80 rpm / min for 1 h. Then add 1.5 mL of 0.1 g / mL sodium hydroxide solution and heat and stir for 10 min. Add 1 g of TEOS dropwise and stir for 0.5 h. Then add 4 mL of 0.01 g / mL sodium aluminate solution and heat and stir for 0.5 h. The obtained product was centrifuged, filtered, washed, and dried. The dried sample was then calcined in a muffle furnace at 550℃ for 3 hours (heating rate of 2℃ / min). Subsequently, it was placed in a muffle furnace and reduced at 400℃ for 2 hours in an H2 / Ar mixed gas with a hydrogen integral of 10%, to obtain the Ru-Co@Al-SiO2 catalyst, denoted as Ru-Co@Al-SiO2-2.
[0056] The mass ratio of Al-SiO2 to the active component Ru is 1:0.04, and the mass ratio of Al-SiO2 to the co-active component Co is 1:0.02.
[0057] Example 7
[0058] First, dissolve 0.2 g of the template agent CTABr in distilled water to prepare an aqueous solution with a concentration of C(CTABr) = 0.005 g / mL. Stir at room temperature until the solution is clear and transparent. Add 2.5 mL of 0.01 g / mL PVP-K60 solution to the above solution, heat to 85 °C, and stir for 0.5 h. Then add 0.0030 g of Ru(NH3)6Cl3 and 0.0145 g of Ce(NO3)2·6H2O to the above solution and stir for 0.5 h. Add 1 mL of 0.1 g / mL ascorbic acid solution and heat and stir at 90 rpm / min for 0.5 h. Then add 2 mL of 0.05 g / mL sodium hydroxide solution and heat and stir for 10 min. Add 1 g of TEOS dropwise and stir for 0.5 h, then add 2 mL of 0.02 g / mL sodium aluminate solution and heat and stir for 2 h. The obtained product was centrifuged, filtered, washed, and dried. The dried sample was then calcined in a muffle furnace at 550℃ for 3 hours (heating rate of 2℃ / min). Subsequently, it was placed in a muffle furnace and reduced at 400℃ for 2 hours in an H2 / Ar mixed gas with a hydrogen integral of 10%, to obtain the Ru-Ce@Al-SiO2 catalyst, denoted as Ru-Ce@Al-SiO2-1.
[0059] The mass ratio of Al-SiO2 to the active component Ru is 1:0.03, and the mass ratio of Al-SiO2 to the co-active component Ce is 1:0.015.
[0060] Example 8
[0061] First, dissolve 0.25 g of the template agent CTABr in distilled water to prepare an aqueous solution with a concentration of C(CTABr) = 0.0075 g / mL. Stir at room temperature until the solution is clear and transparent. Add 1.5 mL of 0.02 g / mL PVP-K60 solution to the above solution, heat to 90 °C, and stir for 0.5 h. Then add 0.0050 g of Ru(NH3)6Cl3 and 0.0194 g of Ce(NO3)2·6H2O to the above solution and stir for 0.5 h. Add 1 mL of 0.15 g / mL ascorbic acid solution and heat and stir at 100 r / min for 0.5 h. Then add 1.5 mL of 0.1 g / mL sodium hydroxide solution and heat and stir for 0.5 h. Add 1 g of TEOS dropwise and stir for 0.5 h, then add 4 mL of 0.01 g / mL sodium aluminate solution and heat and stir for 1.5 h. The obtained product was centrifuged, filtered, washed, and dried. The dried sample was then calcined in a muffle furnace at 550℃ for 3 hours (heating rate of 2℃ / min). Subsequently, it was placed in a muffle furnace and reduced at 400℃ for 2 hours in an H2 / Ar mixed gas with a hydrogen integral of 10%, to obtain the Ru-Ce@Al-SiO2 catalyst, denoted as Ru-Ce@Al-SiO2-2.
[0062] The mass ratio of Al-SiO2 to the active component Ru is 1:0.05, and the mass ratio of Al-SiO2 to the co-active component Ce is 1:0.02.
[0063] Comparative Example 1
[0064] First, 0.0050 g of Ru(NH3)6Cl3 and 0.0194 g of Ce(NO3)2·6H2O were added to water and stirred for 0.5 h. Then, 1 mL of 0.15 g / mL ascorbic acid solution was added, and the mixture was heated and stirred at 100 r / min for 0.5 h. Next, 1.5 mL of 0.1 g / mL sodium hydroxide solution was added, and the mixture was heated and stirred for 0.5 h. Then, 1 g of TEOS was added dropwise, and the mixture was stirred for 0.5 h. Finally, 4 mL of 0.01 g / mL sodium aluminate solution was added, and the mixture was heated and stirred for 2 h. The resulting product was centrifuged, filtered, washed, and dried. The dried sample was calcined in a muffle furnace at 550 °C for 3 h (heating rate of 2 °C / min), and then reduced in a muffle furnace at 400 °C for 2 h in an H2 / Ar mixed gas with a hydrogen integral of 10%, to obtain the Ru-Ce@Al-SiO2 catalyst. This catalyst is designated as Ru-Ce@Al-SiO2-Comparative 2.
[0065] The mass ratio of Al-SiO2 to the active component Ru is 1:0.05, and the mass ratio of Al-SiO2 to the co-active component Ce is 1:0.02.
[0066] Catalyst performance evaluation:
[0067] The Ru-M@Al-SiO2 catalysts prepared in Examples 1-8 and the catalysts prepared in the comparative examples were used to catalyze the synthesis of hydrogenated tetramethyl pyromellitic acid from tetramethyl pyromellitic acid.
[0068] Application Example 1
[0069] 1.0 g of tetramethyl pyromellitic acid (TMA), 0.04 g of Ru-W@Al-SiO2-1 catalyst, and 25.00 g of isopropanol solvent were weighed sequentially, i.e., the mass ratio of raw material to catalyst was 1:0.04 and the mass ratio of raw material to solvent was 1:25. These were added to a high-pressure reactor. The air inside the reactor was replaced three times with hydrogen gas. Hydrogen gas was then introduced into the reactor until the pressure reached 6 MPa. The stirring speed was adjusted to 600 r / min, and the temperature was raised to the reaction temperature of 100 °C. The reaction was initiated and carried out for 5 hours. After the reaction, the catalyst was separated by centrifugation. Liquid chromatography analysis of the resulting liquid showed a conversion rate of 99.31% and a selectivity of 99.16%.
[0070] Application Example 2
[0071] 1.0 g of tetramethyl pyromellitic acid (TMA), 0.03 g of Ru-W@Al-SiO2-2 catalyst, and 30.00 g of ethanol solvent were weighed sequentially, i.e., the mass ratio of raw material to catalyst was 1:0.03 and the mass ratio of raw material to solvent was 1:30. These were added to a high-pressure reactor. The air inside the reactor was replaced three times with hydrogen gas. Hydrogen gas was then introduced into the reactor until the pressure reached 5 MPa. The stirring speed was adjusted to 600 r / min, and the temperature was raised to the reaction temperature of 90 °C. The reaction was initiated and carried out for 4 hours. After the reaction, the catalyst was separated by centrifugation. The resulting liquid was analyzed by liquid chromatography, showing a conversion rate of 99.26% and a selectivity of 98.34%.
[0072] Application Example 3
[0073] 1.0 g of tetramethyl pyromellitic acid (TMA), 0.04 g of Ru-Ni@Al-SiO2-1 catalyst, and 30.00 g of methanol solvent were weighed sequentially, i.e., the mass ratio of raw material to catalyst was 1:0.04 and the mass ratio of raw material to solvent was 1:30. These were added to a high-pressure reactor. The air inside the reactor was replaced three times with hydrogen gas. Hydrogen gas was then introduced into the reactor until the pressure reached 4 MPa. The stirring speed was adjusted to 600 r / min, and the temperature was raised to the reaction temperature of 80 °C. The reaction was initiated and carried out for 5 hours. After the reaction, the catalyst was separated by centrifugation. Liquid chromatography analysis of the resulting liquid showed a conversion rate of 99.46% and a selectivity of 99.03%.
[0074] Application Example 4
[0075] 1.0 g of tetramethyl pyromellitic acid (TMA), 0.05 g of Ru-Ni@Al-SiO2-2 catalyst, and 20.00 g of isopropanol solvent were weighed sequentially, i.e., the mass ratio of raw material to catalyst was 1:0.05 and the mass ratio of raw material to solvent was 1:20. These were added to a high-pressure reactor. The air inside the reactor was replaced three times with hydrogen gas. Hydrogen gas was then introduced into the reactor until the pressure reached 5 MPa. The stirring speed was adjusted to 600 r / min, and the temperature was raised to the reaction temperature of 90 °C. The reaction was initiated and carried out for 4 hours. After the reaction, the catalyst was separated by centrifugation. The resulting liquid was analyzed by liquid chromatography, showing a conversion rate of 98.92% and a selectivity of 99.10%.
[0076] Application Example 5
[0077] 1.0 g of tetramethyl pyromellitic acid (TMA), 0.05 g of Ru-Co@Al-SiO2-1 catalyst, and 25.00 g of isopropanol solvent were weighed sequentially, i.e., the mass ratio of raw material to catalyst was 1:0.05 and the mass ratio of raw material to solvent was 1:25. These were added to a high-pressure reactor. The air inside the reactor was replaced three times with hydrogen gas. Hydrogen gas was then introduced into the reactor until the pressure reached 6 MPa. The stirring speed was adjusted to 600 r / min, and the temperature was raised to the reaction temperature of 100 °C. The reaction was initiated and carried out for 6 hours. After the reaction, the catalyst was separated by centrifugation. The resulting liquid was analyzed by liquid chromatography, showing a conversion rate of 98.16% and a selectivity of 97.35%.
[0078] Application Example 6
[0079] 1.0 g of tetramethyl pyromellitic acid (TMA), 0.03 g of Ru-Co@Al-SiO2-2 catalyst, and 20.00 g of DMF solvent were weighed sequentially, i.e., the mass ratio of raw material to catalyst was 1:0.03 and the mass ratio of raw material to solvent was 1:20. These were added to a high-pressure reactor. The air inside the reactor was replaced three times with hydrogen gas. Hydrogen gas was then introduced into the reactor until the pressure reached 5 MPa. The stirring speed was adjusted to 600 r / min, and the temperature was raised to the reaction temperature of 90 °C. The reaction was initiated and carried out for 5 hours. After the reaction, the catalyst was separated by centrifugation. Liquid chromatography analysis of the resulting liquid showed a conversion rate of 97.48% and a selectivity of 98.12%.
[0080] Application Example 7
[0081] 1.0 g of tetramethyl pyromellitic acid (TMA), 0.04 g of Ru-Ce@Al-SiO2-1 catalyst, and 30.00 g of methanol solvent were weighed sequentially, i.e., the mass ratio of raw material to catalyst was 1:0.04 and the mass ratio of raw material to solvent was 1:30. These were added to a high-pressure reactor. The air inside the reactor was replaced three times with hydrogen gas. Hydrogen gas was then introduced into the reactor until the pressure reached 5 MPa. The stirring speed was adjusted to 600 r / min, and the temperature was raised to the reaction temperature of 100 °C. The reaction was initiated and carried out for 6 hours. After the reaction was completed, the catalyst was separated by centrifugation. Liquid chromatography analysis of the resulting liquid showed a conversion rate of 98.85% and a selectivity of 98.77%.
[0082] Application Example 8
[0083] 1.0 g of tetramethyl pyromellitic acid (TMA), 0.03 g of Ru-Ce@Al-SiO2-2 catalyst, and 25.00 g of isopropanol solvent were weighed sequentially, i.e., the mass ratio of raw material to catalyst was 1:0.03 and the mass ratio of raw material to solvent was 1:25. These were added to a high-pressure reactor. The air inside the reactor was replaced three times with hydrogen gas. Hydrogen gas was then introduced into the reactor until the pressure reached 4 MPa. The stirring speed was adjusted to 600 r / min, and the temperature was raised to the reaction temperature of 80 °C. The reaction was initiated and carried out for 4 hours. After the reaction, the catalyst was separated by centrifugation. The resulting liquid was analyzed by liquid chromatography, showing a conversion rate of 99.37% and a selectivity of 99.24%.
[0084] The separated catalyst was recycled using the above reaction method, and its stability was investigated. The results of the catalyst stability evaluation are as follows: Figure 2 As shown in the figure, even after recycling the catalyst five times, the conversion rate can still reach approximately 90%.
[0085] Application Example 9
[0086] 1.0 g of tetramethyl pyromellitic acid (TMA), 0.03 g of Ru-Ce@Al-SiO2-BiS2 catalyst, and 25.00 g of isopropanol solvent were weighed sequentially, i.e., the mass ratio of raw material to catalyst was 1:0.03 and the mass ratio of raw material to solvent was 1:25. These were added to a high-pressure reactor. The air inside the reactor was replaced three times with hydrogen gas. Hydrogen gas was then introduced into the reactor until the pressure reached 4 MPa. The stirring speed was adjusted to 600 r / min, and the temperature was raised to the reaction temperature of 80 °C. The reaction was initiated and carried out for 4 hours. After the reaction, the catalyst was separated by centrifugation. Liquid chromatography analysis of the resulting liquid showed a conversion rate of 43.25% and a selectivity of 96.28%.
[0087] The experimental results for each application example are shown in Table 1:
[0088] Table 1. Experimental Results of Application Examples
[0089]
[0090] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims.
Claims
1. A core-shell structured Ru-M@Al-SiO2 catalyst, characterized in that, It is composed of active component Ru, co-active component M and Al-SiO2 support; the active component Ru and co-active component M form the core layer, and the Al-SiO2 support forms the shell; the catalyst has a microsphere morphology. The mass ratio of Al-SiO2 support to active component Ru is 1:0.02~0.05; the mass ratio of Al-SiO2 support to co-active component M is 1:0.01~0.
025. The auxiliary active component M is one of the transition metals W, Ni, Co, and Ce.
2. The preparation method of the core-shell structure Ru-M@Al-SiO2 catalyst according to claim 1, characterized in that, Includes the following steps: (1) Weigh the template agent CTABr into distilled water, add PVP solution, and heat and stir for 0.5~2 h; (2) Add Ru(NH3)6Cl3 solution and M metal salt solution, (3) Add ascorbic acid solution and sodium hydroxide solution, keep heating and stirring for 0.5~2 h, and add TEOS dropwise; (4) Add sodium aluminate solution, keep heating and stirring for 0.5~2 h, and after the reaction is complete, centrifuge, filter, wash, dry and calcinate to reduce and obtain Ru-M@Al-SiO2 catalyst; In step (1), the concentration of CTABr is 0.005~0.01 g / mL, and the concentration of PVP solution is 0.01~0.02 g / mL; in step (3), the concentration of ascorbic acid solution is 0.1~0.2 g / mL, and the concentration of sodium hydroxide solution is 0.05~0.1 g / mL; in step (4), the concentration of sodium aluminate solution is 0.01~0.02 g / mL. The mass ratio of TEOS to CTABr is 1:0.2~0.3; the mass ratio of TEOS to PVP is 1:0.02~0.03; the mass ratio of TEOS to Ru(NH3)6Cl3 is 1:0.002~0.005; the mass ratio of TEOS to M metal salt is 1:0.0042~0.0387; the mass ratio of TEOS to ascorbic acid is 1:0.1~0.15; the mass ratio of TEOS to sodium hydroxide is 1:0.1~0.15; and the mass ratio of TEOS to sodium aluminate is 1:0.
04. The heating and stirring temperature is 80~90℃, and the stirring speed is 80~100 r / min.
3. The preparation method according to claim 2, characterized in that, In step (2), the M metal salt is H 28 N6O 41 W 12 Any one of Ni(NO3)2·6H2O, Co(NO3)2·6H2O or Ce(NO3)2·6H2O.
4. The application of the core-shell structure Ru-M@Al-SiO2 catalyst according to claim 1 in the catalytic synthesis of hydrogenated tetramethyl pyromellitic acid from tetramethyl pyromellitic acid.
5. The application according to claim 4, characterized in that, The Ru-M@Al-SiO2 catalyst, tetramethyl pyromellitic acid, and solvent were added sequentially to a reaction vessel. After replacing the air in the vessel with hydrogen, the vessel was pressurized and heated to the reaction temperature to begin the reaction. After the reaction was completed, the catalyst was separated by centrifugation. The mass ratio of tetramethyl pyromellitic acid to Ru-M@Al-SiO2 catalyst was 1:0.03~0.05; the mass ratio of tetramethyl pyromellitic acid to solvent was 1:20~30; the reaction temperature was 80~100℃, the hydrogen pressure was 4~6 MPa, and the reaction time was 4~6 h.
6. The application according to claim 5, characterized in that, The solvent is selected from one or more of methanol, ethanol, isopropanol or DMF.