Alumina-based catalyst for anthraquinone hydrogenation and preparation method thereof

Abstract

The invention belongs to the technical field of catalysts, and particularly relates to an alumina-based catalyst for anthraquinone hydrogenation and a preparation method thereof.The preparation method comprises the following steps that 1, aluminum salt and PVP are added into deionized water, and an aluminum salt mixed solution is obtained; (2) adding ammonium salt and cyclic polysaccharide micromolecules into deionized water to obtain an ammonium salt mixed solution; (3) dropwise adding the aluminum salt mixed solution into the ammonium salt mixed solution while stirring, and performing aging, suction filtration, drying and calcination to obtain an alumina carrier; (4) impregnating the alumina carrier with a palladium salt solution; and (5) drying, roasting and reducing the impregnated alumina carrier to obtain the alumina-based catalyst for anthraquinone hydrogenation. Macromolecular PVP (Polyvinyl Pyrrolidone) and cyclic polysaccharide micromolecules are used as composite template agents for ammonium-aluminum coprecipitation, so that not only is an alumina carrier material with a high specific surface area prepared, but also the loading capacity on palladium is improved, the dispersion of palladium is promoted, and the hydrogenation efficiency is favorably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and particularly relates to an alumina-based catalyst for anthraquinone hydrogenation and a preparation method thereof. Background Art

[0002] Hydrogen peroxide, commonly known as hydrogen peroxide, is a very important green fine chemical in industry. At room temperature and pressure, hydrogen peroxide is a colorless, transparent liquid that is miscible with water in all proportions. During use, hydrogen peroxide only produces oxygen and water molecules, without polluting the environment, making it an environmentally friendly green chemical product. Due to its excellent oxidizing and environmentally friendly properties, it is widely used in various industries, including environmental protection, green organic synthesis, medical disinfection, papermaking, textiles, and aerospace.

[0003] Hydrogen peroxide can undergo a variety of reactions, including decomposition, oxidation, addition, reduction, and substitution. Furthermore, hydrogen peroxide offers significant advantages in organic synthesis, including environmental friendliness, relatively mild reaction conditions, and water solubility. Therefore, hydrogen peroxide has become one of the most promising green chemical reagents in the field of organic chemical synthesis. Hydrogen peroxide can also be used in the electronics industry as a high-purity aqueous hydrogen peroxide solution, also known as electronic-grade hydrogen peroxide. It is an essential electronic chemical raw material in large-scale integrated circuit production processes, primarily used for cleaning the surfaces of silicon wafers and semiconductor circuit boards. The bleaching effect of hydrogen peroxide plays a crucial role in both the papermaking and textile industries. As an excellent oxygen-containing bleaching agent, hydrogen peroxide exhibits advantages such as a fast oxidation reaction rate, high whiteness, resistance to yellowing after prolonged storage, minimal environmental pollution, and easy wastewater treatment under alkaline conditions. Furthermore, hydrogen peroxide is widely used in the bleaching of fabrics and paper pulp due to its minimal damage to textile fibers.

[0004] Numerous industrial production methods for hydrogen peroxide have been discovered, including inorganic chemical reactions, electrolysis, the isopropyl alcohol method, cathode-anodic reduction, direct hydrogen-oxygen synthesis, and the anthraquinone method. The anthraquinone method, with its mature production technology and ease of scalability, has become the most widely used method for producing hydrogen peroxide.

[0005] Supported palladium-based catalysts are the most commonly used in anthraquinone hydrogenation processes, and the selection and modification of palladium supports has long been a research hotspot in this field. A variety of supports can be used as catalyst supports, including alumina, titania, silica, carbon materials, and silica-alumina gels. Current research focuses primarily on alumina or silica. Alumina, with its rich pores, large surface area, excellent mechanical strength, and acid and alkali resistance, is often used as a support for anthraquinone hydrogenation catalysts. Among these, a series of patents filed by Sinopec (CN119425796A, CN119524886A, CN119098224A, and CN116022834A, among others) describe the preparation of various high-surface-area aluminas through direct modification of alumina or coprecipitation-calcination processes, and their performance as catalyst supports has been investigated. A series of patents filed by Shandong Gongquan Chemical Co., Ltd. (CN118045581A, CN118788318A, CN118807722A, CN118929711A, etc.) and patent CN117985748A filed by Shandong Jirun Nano New Materials Co., Ltd. also investigate the effects of different surfactants or templates on alumina supports and alumina nanopowders. The alumina support preparation processes used in these patents are complex, and the resulting alumina nanopowders lack a porous structure, making them unusable as catalyst supports. Therefore, there is an urgent need to develop a highly efficient alumina-based catalyst for anthraquinone hydrogenation. Summary of the Invention

[0006] The present invention provides an alumina-based catalyst for anthraquinone hydrogenation and a preparation method thereof. A high specific surface area and large pore size alumina carrier is prepared by compounding linear macromolecule PVP and cyclic polysaccharide small molecules, thereby solving the technical problem of low hydrogenation efficiency of traditional alumina-based palladium catalysts.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows: A method for preparing an alumina-based catalyst for anthraquinone hydrogenation comprises the following steps: (1) Add aluminum salt and PVP to deionized water and stir evenly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is not greater than 15,000; in order to promote the dissolution and dispersion of the PVP, heating may be appropriately performed during the stirring process; (2) adding ammonium salt and cyclic polysaccharide small molecules to deionized water, uniformly dispersing them by ultrasonication, and adjusting the pH of the solution to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecules to the PVP in step (1) is (0.1-0.5):1; (3) adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring; after the addition is completed, aging, filtering, drying, and calcining to obtain an alumina support; (4) dispersing the palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina support obtained in step (3) with the palladium salt solution; (5) The impregnated alumina support is dried, calcined, and reduced to obtain an alumina-based catalyst for anthraquinone hydrogenation.

[0008] Polyvinylpyrrolidone (PVP), a linear high-molecular polymer, is a typical nonionic surfactant. PVP molecules contain hydrophilic lactam groups and lipophilic methylene and methine groups. The chemical environments at both ends of the amide groups are different: the oxygen is exposed, while the nitrogen is surrounded by the methylene and methine groups. This chemical structure can sterically shield the adsorption and hydrophilic effects on the surface of solid particles, resulting in excellent dispersion stability of the particles. Therefore, PVP is suitable as a template and surfactant for preparing porous alumina materials. The macromolecular polyvinylpyrrolidone has repeating structural units, and the repetitiveness of the structural unit groups can achieve directional adsorption on particles, producing alumina materials with controllable morphology. However, the specific surface area of ​​alumina supports prepared using a single PVP template is limited. To this end, the present invention adds a certain amount of cyclic polysaccharide small molecules as templates and surfactants. The nitrogen-containing groups and carbonyl groups on PVP can form hydrogen bonds with the hydroxyl groups on the cyclic polysaccharide small molecules. This not only improves the dispersion performance of the large-molecule PVP by utilizing the easy solubility of the cyclic polysaccharide small molecules, but also provides more soft template forms to promote the dispersion of grains. In addition, the introduction of the ring structure of the cyclic polysaccharide small molecules avoids the poor controllability of a single PVP template agent, promotes the controlled formation of the alumina support, and is beneficial to increasing the specific surface area and pore size of the alumina support.

[0009] In one embodiment, the aluminum salt in step (1) is one of aluminum nitrate, aluminum sulfate, and aluminum chloride; and the aluminum salt concentration in the aluminum salt mixed solution is 0.1-0.5 mol / L.

[0010] In one embodiment, the number average molecular weight of PVP in step (1) is 5000-15000. In order to improve the activity of PVP, the molecular weight of PVP should be reasonably adjusted. On the basis of exerting the surface activity of its long molecular chain, it is necessary to prevent the molecular weight of PVP from being too high, which makes it difficult for the molecular chain to move and reduces the template effect and surfactant effect. Furthermore, the number average molecular weight of PVP is any value between 7000-15000, 8000-15000, 9000-14000 or 10000-13000. The mass ratio of PVP to aluminum salt is (0.1-0.6):1. Specifically, the mass ratio of PVP to aluminum salt is 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1 or 0.6:1. Particularly preferably, the mass ratio of PVP to aluminum salt is 0.2:1, 0.3:1 or 0.4:1. An appropriate amount of PVP can fully exert the role of surfactant and avoid the negative impact of excessive viscosity.

[0011] In one embodiment, the ammonium salt in step (2) is one of ammonium nitrate, ammonium sulfate, and ammonium bicarbonate; the ammonium salt concentration in the ammonium salt mixed solution is 0.5-1 mol / L; and the molar ratio of the ammonium salt to the aluminum salt in step (1) is (5-10):1.

[0012] In one embodiment, the cyclic polysaccharide small molecule in step (2) is cyclodextrin and its derivatives. Cyclodextrin and its derivatives from biomass are used as auxiliary templates and surfactants and can be directly prepared from starch. The material source is wide and the cost is low.

[0013] In one embodiment, the cyclodextrin and its derivatives are at least one of β-cyclodextrin, γ-cyclodextrin, hydroxypropyl-β-cyclodextrin, disaccharide-β-cyclodextrin, methyl-β-cyclodextrin or hydroxyethyl-β-cyclodextrin. In particular, the cyclodextrin and its derivatives are hydroxypropyl-β-cyclodextrin. Compared with other types of cyclodextrins, hydroxypropyl-β-cyclodextrin has better solubility, can fully improve the dispersibility of macromolecular PVP, and help to construct the porous structure of alumina. However, the amount of hydroxypropyl-β-cyclodextrin should not be too much. Excessive use is not conducive to the stability of the PVP micelle structure and the stability of the porous structure during calcination, affecting the increase in the specific surface area of ​​alumina and the increase in pore size. In particular, the mass ratio of the cyclic polysaccharide small molecule to the PVP in step (1) is 0.1:1, 0.2:1, 0.3:1, 0.4:1, or 0.5:1; particularly preferably, it is 0.2:1, 0.3:1, or 0.4:1.

[0014] In one embodiment, the pH value in step (2) is 9-10.

[0015] In one embodiment, the dropping rate of the aluminum salt mixed solution in step (3) is 1-40 mL / min; the calcination temperature is 650-750° C., and the calcination time is 4-6 h.

[0016] In one embodiment, the calcination temperature in step (5) is 300-350°C, and the calcination time is 3-4 hours; the reduction is performed using a 10 vol% hydrogen / argon mixture at 160-200°C for 2.5-3.5 hours.

[0017] The form of the palladium salt in step (4) is not particularly limited. In particular, the palladium salt is palladium acetate and the solvent is acetone. The impregnation can be performed using an equal volume impregnation process. As for the palladium salt concentration, a palladium salt solution can be prepared based on a palladium loading of 0.1-1 wt% in the catalyst support. For example, a palladium salt solution can be prepared based on a palladium loading of 0.2 wt% in the catalyst support. After calcination and reduction, a palladium-containing alumina-based anthraquinone hydrogenation catalyst with a loading of 0.2 wt% is obtained.

[0018] On the other hand, the present invention also provides an alumina-based catalyst for anthraquinone hydrogenation, using macromolecular PVP and small cyclic polysaccharide molecules as composite templates for ammonium-aluminum co-precipitation, which not only prepares an alumina support material with a high specific surface area, but also improves the loading capacity for palladium, promotes the dispersion of palladium, and is beneficial to improving the hydrogenation efficiency.

[0019] Beneficial effects: The macromolecular polyvinylpyrrolidone has repeating structural units. The repetitiveness of the structural unit groups can achieve directional adsorption of particles to produce alumina materials with controllable morphology. At the same time, a small amount of cyclic polysaccharide small molecules is added as templates and surfactants. The nitrogen-containing groups and carbonyl groups on PVP can form hydrogen bonds with the hydroxyl groups on the cyclic polysaccharide small molecules. Not only can the solubility of the cyclic polysaccharide small molecules be used to improve the dispersion performance of the macromolecular PVP, but more soft template forms can also be provided to promote the dispersion of grains. In addition, by introducing the annular structure of the cyclic polysaccharide small molecules, the shortcomings of the poor controllability of a single PVP template can be avoided, the controllable formation of the alumina carrier can be promoted, and the specific surface area of ​​the alumina carrier can be increased. The alumina carrier with a high specific surface area has a strong loading capacity for palladium, which promotes the dispersion of palladium and is beneficial to improving the hydrogenation efficiency. DETAILED DESCRIPTION

[0020] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below with reference to specific embodiments and comparative examples. The purpose is to provide a detailed understanding of the content of the present invention, but not to limit the present invention. All other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0021] Example 1 A method for preparing an alumina-based catalyst for anthraquinone hydrogenation comprises the following steps: (1) adding aluminum salt and PVP to deionized water and stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 9000; the aluminum salt is aluminum nitrate; the aluminum salt concentration in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of PVP to aluminum salt is 0.1:1; (2) adding ammonium salt and cyclic polysaccharide small molecules to deionized water, uniformly dispersing them by ultrasonication, and adjusting the pH value of the solution to 9 to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecules to the PVP in step (1) is 0.25:1; the ammonium salt is ammonium bicarbonate; the ammonium salt concentration in the ammonium salt mixed solution is 0.7 mol / L; the molar ratio of the ammonium salt to the aluminum salt in step (1) is 6:1; the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin; (3) Adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, aging, filtering, drying, and calcining to obtain an alumina support; the aluminum salt mixed solution was added at a rate of 12 mL / min; the calcination temperature was 650°C, and the calcination time was 6 h; (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina support obtained in step (3) with the palladium salt solution; the palladium salt is palladium acetate, and the solvent is acetone; the impregnation is an equal volume impregnation process; in step (4), the palladium salt solution is prepared so that the palladium loading in the alumina support is 0.2 wt%; (5) The impregnated alumina carrier was dried, calcined, and reduced to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature was 300°C, and the calcination time was 4 hours; and the reduction was performed using a 10 vol% hydrogen / argon mixture at 170°C for 3.5 hours.

[0022] Example 2 A method for preparing an alumina-based catalyst for anthraquinone hydrogenation comprises the following steps: (1) adding aluminum salt and PVP to deionized water and stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 15,000; the aluminum salt is aluminum nitrate; the aluminum salt concentration in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of PVP to aluminum salt is 0.4:1; (2) adding ammonium salt and cyclic polysaccharide small molecules to deionized water, uniformly dispersing them by ultrasonication, and adjusting the pH value of the solution to 10 to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecules to the PVP in step (1) is 0.5:1; the ammonium salt is ammonium bicarbonate; the ammonium salt concentration in the ammonium salt mixed solution is 0.7 mol / L; the molar ratio of the ammonium salt to the aluminum salt in step (1) is 9:1; the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin; (3) Adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, aging, filtering, drying, and calcining to obtain an alumina support; the aluminum salt mixed solution was added dropwise at a rate of 18 mL / min; the calcination temperature was 750°C, and the calcination time was 4 h; (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina support obtained in step (3) with the palladium salt solution; the palladium salt is palladium acetate, and the solvent is acetone; the impregnation is an equal volume impregnation process; in step (4), the palladium salt solution is prepared so that the palladium loading in the alumina support is 0.2 wt%; (5) The impregnated alumina carrier was dried, calcined, and reduced to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature was 350°C, and the calcination time was 3 h; the reduction was carried out using a 10 vol% hydrogen / argon mixture at 190°C for 2.5 h.

[0023] Example 3 A method for preparing an alumina-based catalyst for anthraquinone hydrogenation comprises the following steps: (1) adding aluminum salt and PVP to deionized water and stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 7000; the aluminum salt is aluminum nitrate; the aluminum salt concentration in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of PVP to aluminum salt is 0.3:1; (2) adding ammonium salt and cyclic polysaccharide small molecules to deionized water, uniformly dispersing them by ultrasonication, and adjusting the pH value of the solution to 9.5 to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecules to the PVP in step (1) is 0.35:1; the ammonium salt is ammonium bicarbonate; the ammonium salt concentration in the ammonium salt mixed solution is 0.7 mol / L; the molar ratio of the ammonium salt to the aluminum salt in step (1) is 8:1; the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin; (3) Adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, aging, filtering, drying, and calcining to obtain an alumina support; the aluminum salt mixed solution was added at a rate of 15 mL / min; the calcination temperature was 710°C, and the calcination time was 5 h; (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina support obtained in step (3) with the palladium salt solution; the palladium salt is palladium acetate, and the solvent is acetone; the impregnation is an equal volume impregnation process; in step (4), the palladium salt solution is prepared so that the palladium loading in the alumina support is 0.2 wt%; (5) The impregnated alumina carrier was dried, calcined, and reduced to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature was 320°C, and the calcination time was 3.5 h; the reduction was performed using a 10 vol% hydrogen / argon mixture at 180°C for 3 h.

[0024] Example 4 A method for preparing an alumina-based catalyst for anthraquinone hydrogenation comprises the following steps: (1) adding aluminum salt and PVP to deionized water and stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 10,000; the aluminum salt is aluminum nitrate; the aluminum salt concentration in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of PVP to aluminum salt is 0.4:1; (2) adding ammonium salt and cyclic polysaccharide small molecules to deionized water, uniformly dispersing them by ultrasonication, and adjusting the pH value of the solution to 9 to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecules to the PVP in step (1) is 0.5:1; the ammonium salt is ammonium bicarbonate; the ammonium salt concentration in the ammonium salt mixed solution is 0.7 mol / L; the molar ratio of the ammonium salt to the aluminum salt in step (1) is 6:1; the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin; (3) Adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, aging, filtering, drying, and calcining to obtain an alumina support; the aluminum salt mixed solution was added dropwise at a rate of 15 mL / min; the calcination temperature was 650°C, and the calcination time was 4 h; (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina support obtained in step (3) with the palladium salt solution; the palladium salt is palladium acetate, and the solvent is acetone; the impregnation is an equal volume impregnation process; in step (4), the palladium salt solution is prepared so that the palladium loading in the alumina support is 0.2 wt%; (5) The impregnated alumina support was dried, calcined, and reduced to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature was 300°C, and the calcination time was 3 h; the reduction was performed using a 10 vol% hydrogen / argon mixture at 190°C for 3.5 h.

[0025] Example 5 A method for preparing an alumina-based catalyst for anthraquinone hydrogenation comprises the following steps: (1) adding aluminum salt and PVP to deionized water and stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 12000; the aluminum salt is aluminum nitrate; the aluminum salt concentration in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of PVP to aluminum salt is 0.6:1; (2) adding ammonium salt and cyclic polysaccharide small molecules to deionized water, uniformly dispersing them by ultrasonication, and adjusting the pH value of the solution to 9.5 to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecules to the PVP in step (1) is 0.35:1; the ammonium salt is ammonium bicarbonate; the ammonium salt concentration in the ammonium salt mixed solution is 0.7 mol / L; the molar ratio of the ammonium salt to the aluminum salt in step (1) is 8:1; the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin; (3) Adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, aging, filtering, drying, and calcining to obtain an alumina support; the aluminum salt mixed solution was added at a rate of 15 mL / min; the calcination temperature was 710°C, and the calcination time was 5 h; (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina support obtained in step (3) with the palladium salt solution; the palladium salt is palladium acetate, and the solvent is acetone; the impregnation is an equal volume impregnation process; in step (4), the palladium salt solution is prepared so that the palladium loading in the alumina support is 0.2 wt%; (5) The impregnated alumina carrier was dried, calcined, and reduced to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature was 320°C, and the calcination time was 3.5 h; the reduction was performed using a 10 vol% hydrogen / argon mixture at 180°C for 3 h.

[0026] Example 6 A method for preparing an alumina-based catalyst for anthraquinone hydrogenation comprises the following steps: (1) adding aluminum salt and PVP to deionized water and stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 13000; the aluminum salt is aluminum nitrate; the aluminum salt concentration in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of PVP to aluminum salt is 0.25:1; (2) adding ammonium salt and cyclic polysaccharide small molecules to deionized water, uniformly dispersing them by ultrasonication, and adjusting the pH value of the solution to 9 to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecules to the PVP in step (1) is 0.3:1; the ammonium salt is ammonium bicarbonate; the ammonium salt concentration in the ammonium salt mixed solution is 0.7 mol / L; the molar ratio of the ammonium salt to the aluminum salt in step (1) is 7:1; the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin; (3) Adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, aging, filtering, drying, and calcining to obtain an alumina support; the aluminum salt mixed solution was added dropwise at a rate of 14 mL / min; the calcination temperature was 680°C, and the calcination time was 5.5 h; (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina support obtained in step (3) with the palladium salt solution; the palladium salt is palladium acetate, and the solvent is acetone; the impregnation is an equal volume impregnation process; in step (4), the palladium salt solution is prepared so that the palladium loading in the alumina support is 0.2 wt%; (5) The impregnated alumina carrier was dried, calcined, and reduced to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature was 310°C, and the calcination time was 3.8 h; the reduction was carried out using a 10 vol% hydrogen / argon mixture at 180°C for 3.2 h.

[0027] Example 7 A method for preparing an alumina-based catalyst for anthraquinone hydrogenation comprises the following steps: (1) adding aluminum salt and PVP to deionized water and stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 12000; the aluminum salt is aluminum nitrate; the aluminum salt concentration in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of PVP to aluminum salt is 0.3:1; (2) adding ammonium salt and cyclic polysaccharide small molecules to deionized water, uniformly dispersing them by ultrasonication, and adjusting the pH value of the solution to 9.5 to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecules to the PVP in step (1) is 0.1:1; the ammonium salt is ammonium bicarbonate; the ammonium salt concentration in the ammonium salt mixed solution is 0.7 mol / L; the molar ratio of the ammonium salt to the aluminum salt in step (1) is 8:1; the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin; (3) Adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, aging, filtering, drying, and calcining to obtain an alumina support; the aluminum salt mixed solution was added at a rate of 15 mL / min; the calcination temperature was 710°C, and the calcination time was 5 h; (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina support obtained in step (3) with the palladium salt solution; the palladium salt is palladium acetate, and the solvent is acetone; the impregnation is an equal volume impregnation process; in step (4), the palladium salt solution is prepared so that the palladium loading in the alumina support is 0.2 wt%; (5) The impregnated alumina carrier was dried, calcined, and reduced to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature was 320°C, and the calcination time was 3.5 h; the reduction was performed using a 10 vol% hydrogen / argon mixture at 180°C for 3 h.

[0028] Example 8 A method for preparing an alumina-based catalyst for anthraquinone hydrogenation comprises the following steps: (1) adding aluminum salt and PVP to deionized water and stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 10,000; the aluminum salt is aluminum nitrate; the aluminum salt concentration in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of PVP to aluminum salt is 0.35:1; (2) adding ammonium salt and cyclic polysaccharide small molecules to deionized water, uniformly dispersing them by ultrasonication, and adjusting the pH value of the solution to 10 to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecules to the PVP in step (1) is 0.4:1; the ammonium salt is ammonium bicarbonate; the ammonium salt concentration in the ammonium salt mixed solution is 0.7 mol / L; the molar ratio of the ammonium salt to the aluminum salt in step (1) is 8:1; the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin; (3) Adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, aging, filtering, drying, and calcining to obtain an alumina support; the aluminum salt mixed solution was added dropwise at a rate of 16 mL / min; the calcination temperature was 720°C, and the calcination time was 4.5 h; (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina support obtained in step (3) with the palladium salt solution; the palladium salt is palladium acetate, and the solvent is acetone; the impregnation is an equal volume impregnation process; in step (4), the palladium salt solution is prepared so that the palladium loading in the alumina support is 0.2 wt%; (5) The impregnated alumina carrier was dried, calcined, and reduced to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature was 330°C, and the calcination time was 3.4 h; the reduction was carried out using a 10 vol% hydrogen / argon mixture at 180°C for 3.2 h.

[0029] Example 9 A method for preparing an alumina-based catalyst for anthraquinone hydrogenation comprises the following steps: (1) adding aluminum salt and PVP to deionized water and stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 15,000; the aluminum salt is aluminum nitrate; the aluminum salt concentration in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of PVP to aluminum salt is 0.32:1; (2) adding ammonium salt and cyclic polysaccharide small molecules to deionized water, uniformly dispersing them by ultrasonication, and adjusting the pH value of the solution to 9.5 to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecules to the PVP in step (1) is 0.38:1; the ammonium salt is ammonium bicarbonate; in the ammonium salt mixed solution, the ammonium salt concentration is 0.7 mol / L; the molar ratio of the ammonium salt to the aluminum salt in step (1) is 7:1; the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin; (3) Adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, aging, filtering, drying, and calcining to obtain an alumina support; the aluminum salt mixed solution was added dropwise at a rate of 16 mL / min; the calcination temperature was 690°C, and the calcination time was 5.2 h; (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina support obtained in step (3) with the palladium salt solution; the palladium salt is palladium acetate, and the solvent is acetone; the impregnation is an equal volume impregnation process; in step (4), the palladium salt solution is prepared so that the palladium loading in the alumina support is 0.2 wt%; (5) The impregnated alumina support was dried, calcined, and reduced to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature was 325°C, and the calcination time was 3.6 h; the reduction was carried out using a 10 vol% hydrogen / argon mixture at 180°C for 2.8 h.

[0030] Example 10 A method for preparing an alumina-based catalyst for anthraquinone hydrogenation comprises the following steps: (1) adding aluminum salt and PVP to deionized water and stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 12000; the aluminum salt is aluminum nitrate; the aluminum salt concentration in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of PVP to aluminum salt is 0.3:1; (2) adding ammonium salt and cyclic polysaccharide small molecules to deionized water, uniformly dispersing them by ultrasonication, and adjusting the pH value of the solution to 9.5 to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecules to the PVP in step (1) is 0.35:1; the ammonium salt is ammonium bicarbonate; the ammonium salt concentration in the ammonium salt mixed solution is 0.7 mol / L; the molar ratio of the ammonium salt to the aluminum salt in step (1) is 8:1; the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin; (3) Adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, aging, filtering, drying, and calcining to obtain an alumina support; the aluminum salt mixed solution was added at a rate of 15 mL / min; the calcination temperature was 710°C, and the calcination time was 5 h; (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina support obtained in step (3) with the palladium salt solution; the palladium salt is palladium acetate, and the solvent is acetone; the impregnation is an equal volume impregnation process; in step (4), the palladium salt solution is prepared so that the palladium loading in the alumina support is 0.2 wt%; (5) The impregnated alumina carrier was dried, calcined, and reduced to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature was 320°C, and the calcination time was 3.5 h; the reduction was performed using a 10 vol% hydrogen / argon mixture at 180°C for 3 h.

[0031] Comparative Example 1 A method for preparing an alumina-based catalyst for anthraquinone hydrogenation comprises the following steps: (1) adding aluminum salt and PVP to deionized water and stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 20,000; the aluminum salt is aluminum nitrate; the aluminum salt concentration in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of PVP to aluminum salt is 0.3:1; (2) adding ammonium salt and cyclic polysaccharide small molecules to deionized water, uniformly dispersing them by ultrasonication, and adjusting the pH value of the solution to 9.5 to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecules to the PVP in step (1) is 0.35:1; the ammonium salt is ammonium bicarbonate; the ammonium salt concentration in the ammonium salt mixed solution is 0.7 mol / L; the molar ratio of the ammonium salt to the aluminum salt in step (1) is 8:1; the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin; (3) Adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, aging, filtering, drying, and calcining to obtain an alumina support; the aluminum salt mixed solution was added at a rate of 15 mL / min; the calcination temperature was 710°C, and the calcination time was 5 h; (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina support obtained in step (3) with the palladium salt solution; the palladium salt is palladium acetate, and the solvent is acetone; the impregnation is an equal volume impregnation process; in step (4), the palladium salt solution is prepared so that the palladium loading in the alumina support is 0.2 wt%; (5) The impregnated alumina carrier was dried, calcined, and reduced to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature was 320°C, and the calcination time was 3.5 h; the reduction was performed using a 10 vol% hydrogen / argon mixture at 180°C for 3 h.

[0032] Comparative Example 2 A method for preparing an alumina-based catalyst for anthraquinone hydrogenation comprises the following steps: (1) adding aluminum salt and PVP to deionized water and stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 12000; the aluminum salt is aluminum nitrate; the aluminum salt concentration in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of PVP to aluminum salt is 0.3:1; (2) adding ammonium salt and cyclic polysaccharide small molecules to deionized water, uniformly dispersing them by ultrasonication, and adjusting the pH value of the solution to 9.5 to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecules to the PVP in step (1) is 1:1; the ammonium salt is ammonium bicarbonate; the ammonium salt concentration in the ammonium salt mixed solution is 0.7 mol / L; the molar ratio of the ammonium salt to the aluminum salt in step (1) is 8:1; the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin; (3) Adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, aging, filtering, drying, and calcining to obtain an alumina support; the aluminum salt mixed solution was added at a rate of 15 mL / min; the calcination temperature was 710°C, and the calcination time was 5 h; (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina support obtained in step (3) with the palladium salt solution; the palladium salt is palladium acetate, and the solvent is acetone; the impregnation is an equal volume impregnation process; in step (4), the palladium salt solution is prepared so that the palladium loading in the alumina support is 0.2 wt%; (5) The impregnated alumina carrier was dried, calcined, and reduced to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature was 320°C, and the calcination time was 3.5 h; the reduction was performed using a 10 vol% hydrogen / argon mixture at 180°C for 3 h.

[0033] The performance test method of the alumina supports prepared in Examples 1 to 10 and Comparative Examples 1 to 2 was as follows: The specific surface area (m2) of the alumina supports prepared in Examples 1 to 10 and Comparative Examples 1 to 2 was tested by the BET method. 2 / g), pore size (nm), as shown in Table 1-Table 2.

[0034] Performance of alumina-based catalysts for anthraquinone hydrogenation prepared in Examples 1-10 and Comparative Examples 1-2: 2-Ethylanthraquinone was dissolved in a mixed solvent of 1,2,4-trimethylbenzene and trioctyl phosphate (1:1 by volume) to prepare a working solution with a concentration of 120 g / L. 60 mL of the working solution and 1 g of the catalyst were added to a reactor. High-purity hydrogen was used as the feedstock, and the reaction temperature was set at 60°C, the pressure at 0.3 MPa, and the reaction time was 90 minutes. The post-reaction working solution was oxidized by oxygen gas, and the hydrogen peroxide content in the working solution was analyzed by titration with potassium permanganate solution. The hydrogenation efficiency (g / L) was calculated, as shown in Tables 1-2.

[0035] Table 1 Alumina carriers prepared in Examples 1 to 6 Performance of alumina-based catalysts for hydrogenation of 1,2-dimethyl-1,3-dioxolane and anthraquinone

[0036] Table 2 Alumina carriers prepared in Examples 7-10 and Comparative Examples 1-2 Performance of alumina-based catalysts for hydrogenation of 1,2-dimethyl-1,3-dioxolane and anthraquinone

[0037] As can be seen from Table 1 and Table 2, the present invention is based on macromolecular polyvinylpyrrolidone as main template agent, and adds a small amount of cyclic polysaccharide small molecules as auxiliary template agent and surfactant simultaneously. The nitrogen-containing group and carbonyl on PVP can form hydrogen bonds with the hydroxyl on the cyclic polysaccharide small molecules, which can not only utilize the easy solubility characteristics of the cyclic polysaccharide small molecules to improve the dispersion properties of macromolecular PVP, but also can provide more soft template forms, promote the dispersion of crystal grains. In addition, by introducing the annular structure of the cyclic polysaccharide small molecules, the shortcoming of the poor controllability of the single PVP template agent can be avoided, the controlled formation of the alumina carrier is promoted, and the specific surface area of ​​the alumina carrier is conducive to improving the alumina carrier. The alumina carrier with high specific surface area is strong to the loading capacity of palladium, promotes the dispersion of palladium, and is conducive to the raising of hydrogenation efficiency.

[0038] Compared with Example 10, the molecular weight of PVP in Comparative Example 1 is too large, the molecular chain movement is difficult, the template effect and surfactant effect are reduced, the specific surface area of ​​the prepared alumina support is reduced, which is not conducive to the dispersion of active palladium and the hydrogenation efficiency is reduced.

[0039] Compared with Example 10, the amount of hydroxypropyl-β-cyclodextrin cyclic polysaccharide small molecules added in Comparative Example 2 is too much, which is not conducive to the stability of the PVP micelle structure and the stability of the porous structure during calcination, affects the formation of the pore size of the alumina carrier, and reduces the catalytic activity.

[0040] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for preparing an alumina-based catalyst for anthraquinone hydrogenation, characterized in that: The following steps are involved: (1) adding aluminum salt and PVP to deionized water and stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is not greater than 15,000; (2) adding ammonium salt and cyclic polysaccharide small molecules to deionized water, uniformly dispersing them by ultrasonication, and adjusting the pH of the solution to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecules to the PVP in step (1) is (0.1-0.5):1; (3) adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, and after the addition is completed, aging, filtering, drying, and calcining to obtain an alumina support; (4) dispersing the palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina support obtained in step (3) with the palladium salt solution; (5) Drying, calcining, and reducing the alumina support after impregnation in step (4) to obtain an alumina-based catalyst for anthraquinone hydrogenation.

2. The method for preparing an alumina-based catalyst for anthraquinone hydrogenation according to claim 1, wherein: In step (1), the aluminum salt is one of aluminum nitrate, aluminum sulfate, and aluminum chloride; and the aluminum salt concentration in the aluminum salt mixed solution is 0.1-0.5 mol / L.

3. The method for preparing an alumina-based catalyst for anthraquinone hydrogenation according to claim 1, wherein: In the step (1), the number average molecular weight of PVP is 5000-15000; the mass ratio of PVP to aluminum salt is (0.1-0.6):

1.

4. The method for preparing an alumina-based catalyst for anthraquinone hydrogenation according to claim 1, wherein: The ammonium salt in step (2) is one of ammonium nitrate, ammonium sulfate, and ammonium bicarbonate; the ammonium salt concentration in the ammonium salt mixed solution is 0.5-1 mol / L; and the molar ratio of the ammonium salt to the aluminum salt in step (1) is (5-10):

1.

5. The method for preparing an alumina-based catalyst for anthraquinone hydrogenation according to claim 1, wherein: The cyclic polysaccharide small molecules in step (2) are cyclodextrin and its derivatives.

6. The method for preparing an alumina-based catalyst for anthraquinone hydrogenation according to claim 5, wherein: The cyclodextrin and its derivatives are at least one of β-cyclodextrin, γ-cyclodextrin, hydroxypropyl-β-cyclodextrin, disaccharide-β-cyclodextrin, methyl-β-cyclodextrin or hydroxyethyl-β-cyclodextrin.

7. The method for preparing an alumina-based catalyst for anthraquinone hydrogenation according to claim 1, wherein: The pH value in step (2) is 9-10.

8. The method for preparing an alumina-based catalyst for anthraquinone hydrogenation according to claim 1, wherein: In the step (3), the dropping rate of the aluminum salt mixed solution is 1-40 mL / min; the calcination temperature is 650-750° C., and the calcination time is 4-6 h.

9. The method for preparing an alumina-based catalyst for anthraquinone hydrogenation according to claim 1, wherein: In the step (5), the calcination temperature is 300-350°C and the calcination time is 3-4 hours; the reduction is carried out by using a 10 vol% hydrogen / argon mixture at 160-200°C for 2.5-3.5 hours.

10. An alumina-based catalyst for anthraquinone hydrogenation, characterized in that: The catalyst is prepared by the method for preparing an alumina-based catalyst for anthraquinone hydrogenation according to any one of claims 1 to 9.

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