An alumina-based catalyst for anthraquinone hydrogenation and a preparation method thereof

Abstract

The application belongs to the technical field of catalysts, and particularly relates to an alumina-based catalyst for anthraquinone hydrogenation and a preparation method thereof, which comprises the following steps: (1) adding an aluminum salt and PVP into deionized water to obtain an aluminum salt mixed solution; (2) adding an ammonium salt and a cyclic polysaccharide small molecule into deionized water to obtain an ammonium salt mixed solution; (3) adding the aluminum salt mixed solution into the ammonium salt mixed solution drop by drop while stirring, and then aging, suction filtering, drying and calcining to obtain an alumina carrier; (4) impregnating the alumina carrier with a palladium salt solution; and (5) drying, calcining and reducing the impregnated alumina carrier to obtain the alumina-based catalyst for anthraquinone hydrogenation. The macromolecular PVP and the cyclic polysaccharide small molecule are used as a composite template for ammonium-aluminum co-precipitation, so that the alumina carrier material with a high specific surface area is prepared, the loading capacity for palladium is improved, the dispersion of palladium is promoted, and the hydrogenation efficiency is improved.

Description

TECHNICAL FIELD

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

[0002] Hydrogen peroxide, commonly known as hydrogen dioxide, is an important green fine chemical in industry. Hydrogen peroxide is a colorless transparent liquid at normal temperature and pressure, and is miscible with water in any proportion. Hydrogen peroxide can only generate oxygen and water molecules in the use process, and does not pollute the environment, so it is an environmentally friendly green chemical product. Due to its excellent oxidation characteristics and environmental protection characteristics, it is widely used in environmental protection, green organic synthesis, medical disinfection, papermaking industry, textile industry, aerospace industry and other industries.

[0003] Hydrogen peroxide can undergo decomposition reaction, oxidation reaction, addition reaction, reduction reaction and substitution reaction and many different reactions. In addition, hydrogen peroxide has the advantages of environmental friendliness, relatively mild reaction conditions, easy solubility in water and the like in organic synthesis. 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 as a high-purity hydrogen peroxide aqueous solution in the electronic industry, which is also called electronic-grade hydrogen peroxide, and is an electronic chemical raw material necessary for large-scale integrated circuit production processes, mainly used for silicon wafer and semiconductor circuit board surface cleaning. The bleaching effect of hydrogen peroxide plays a very important role in the papermaking and textile industries. As an excellent oxygen-containing bleaching agent, hydrogen peroxide has the advantages of fast oxidation reaction rate, high whiteness, long storage time without yellowing, small environmental pollution, easy treatment of waste water and the like under alkaline conditions, and is widely used in fabric and pulp bleaching processes due to its less damage to fabric fibers.

[0004] Many different industrial production methods of hydrogen peroxide have been found so far, such as inorganic chemical reaction method, electrolysis method, isopropyl alcohol method, cathode and anode reduction method, direct synthesis of hydrogen and oxygen method and anthraquinone method. The anthraquinone method has the advantages of mature production technology, easy scaling and the like, and has become the most widely used preparation method for producing hydrogen peroxide.

[0005] In the anthraquinone hydrogenation process, the most commonly used is the supported palladium-based catalyst, and the selection and modification of its carrier have always been one of the research hotspots in the related field. There are various carriers that can be used as the carrier of the catalyst, such as alumina, titanium dioxide, silicon dioxide, carbon materials, silicon-aluminum glue, etc. At present, the research is mainly based on alumina or silicon dioxide, among which alumina has rich pore channels, large specific surface area, good mechanical strength and can resist acid and alkali, and is often used as a carrier for preparing anthraquinone hydrogenation catalyst. Among them, a series of patents (CN119425796A, CN119524886A, CN119098224A, CN116022834A, etc.) applied by China Petroleum Chemical Corporation prepared various high specific surface area alumina by directly modifying alumina or co-precipitation-calcination process, and studied the performance of the alumina as a catalyst carrier. A series of patents (CN118045581A, CN118788318A, CN118807722A, CN118929711A, etc.) applied by Shandong Gongquan Chemical Co., Ltd. and CN117985748A patent applied by Shandong Jilun Nanometer New Material Co., Ltd. also studied the influence of different surfactants or templates on alumina carrier and alumina nanopowder. The alumina carrier prepared by the above-mentioned patents has a complex process, and the alumina nanopowder prepared does not have a porous structure and cannot be used as a catalyst carrier. Therefore, it is urgent to develop a high-efficiency alumina-based catalyst for anthraquinone hydrogenation. SUMMARY

[0006] The application provides an alumina-based catalyst for anthraquinone hydrogenation and a preparation method thereof, wherein a high specific surface area and large pore size alumina carrier is prepared by compounding linear macromolecular 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-mentioned purposes, the technical scheme of the application is as follows:

[0008] A preparation method of an alumina-based catalyst for anthraquinone hydrogenation, comprising the following steps:

[0009] (1) adding an aluminum salt and PVP into deionized water, stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is not more than 15000; in order to promote the dissolution and dispersion of the PVP, heating can be appropriately performed during stirring;

[0010] (2) adding an ammonium salt and a cyclic polysaccharide small molecule into deionized water, ultrasonic dispersing uniformly, and adjusting the pH of the solution to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecule to the PVP in step (1) is (0.1-0.5):1;

[0011] (3) adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, and after the dropwise addition is completed, obtaining the alumina carrier through aging, suction filtration, drying, and calcination;

[0012] (4) dispersing the palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina carrier obtained in step (3) with the palladium salt solution;

[0013] (5) obtaining the alumina-based catalyst for anthraquinone hydrogenation after drying, calcining, and reducing the impregnated alumina carrier.

[0014] Polyvinylpyrrolidone (PVP) is a linear polymer and a typical non-ionic surfactant. PVP molecules have hydrophilic lactam groups, and lipophilic methylene and methylene groups. The chemical environment at both ends of the amide group is different, with oxygen exposed and nitrogen surrounded by methylene and methylene. This chemical structure can sterically shield the adsorption and hydrophilicity of the solid particle surface, and can make the particles have excellent dispersion stability. Therefore, PVP is suitable for preparing porous alumina materials as a template and a surfactant. Macromolecular polyvinylpyrrolidone has repeating structural units, and the repeatability of the structural unit groups can realize directional adsorption of the particles to prepare shape-controllable alumina materials. However, the specific surface area of the alumina carrier prepared by a single PVP template is limited. Therefore, a certain amount of cyclic polysaccharide small molecules are added as a template and a surfactant. 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 also can provide more soft template forms to promote the dispersion of the crystal grains. In addition, the introduction of the ring structure of the cyclic polysaccharide small molecules avoids the disadvantage of poor controllability of a single PVP template, promotes the controllable formation of the alumina carrier, and is beneficial to improving the specific surface area and pore size of the alumina carrier.

[0015] In an embodiment, the aluminum salt in step (1) is one of aluminum nitrate, aluminum sulfate, and aluminum chloride; and the concentration of the aluminum salt in the aluminum salt mixed solution is 0.1-0.5 mol / L.

[0016] In an 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 long molecular chain, it is necessary to prevent the molecular chain from moving difficultly when the molecular weight of PVP is too high, so as to reduce the template effect and the surface active agent effect. Further, the number average molecular weight of PVP is 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. The appropriate amount of PVP can fully exert the effect of the surface active agent and avoid the negative effects caused by too large viscosity.

[0017] In an embodiment, the ammonium salt in step (2) is one of ammonium nitrate, ammonium sulfate and ammonium bicarbonate. In the mixed solution of ammonium salt, the concentration of ammonium salt is 0.5-1 mol / L. The molar ratio of ammonium salt to aluminum salt in step (1) is (5-10):1.

[0018] In an embodiment, the cyclic polysaccharide small molecule in step (2) is cyclodextrin and its derivatives. The cyclodextrin and its derivatives derived from biomass can be directly prepared from starch, and the material source is extensive and the cost is low.

[0019] In an 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. Particularly, the cyclodextrin and its derivatives are hydroxypropyl-β-cyclodextrin. Compared with other types of cyclodextrin, hydroxypropyl-β-cyclodextrin has better solubility, which can improve the dispersibility of macromolecular PVP and help to build the porous structure of alumina. However, if the amount of hydroxypropyl-β-cyclodextrin is too large, it is not conducive to the stability of PVP micelle structure and the stability of the porous structure during calcination, which affects the increase of specific surface area and the increase of pore size of alumina. Particularly, the mass ratio of the cyclic polysaccharide small molecule to PVP in step (1) is 0.1:1, 0.2:1, 0.3:1, 0.4:1 or 0.5:1. Particularly preferably, the mass ratio is 0.2:1, 0.3:1 or 0.4:1.

[0020] In an embodiment, the pH value in step (2) is 9-10.

[0021] In one embodiment, the dropping speed of the aluminum salt mixed solution in step (3) is 1-40 mL / min; the calcination temperature is 650-750℃, and the calcination time is 4-6h.

[0022] In one embodiment, the calcination temperature in step (5) is 300-350℃, and the calcination time is 3-4h; the reduction is performed by using 10 vol% hydrogen / argon mixed gas at 160-200℃ for 2.5-3.5h.

[0023] In step (4), the form of the palladium salt is not particularly limited, and in particular, the palladium salt is palladium acetate, and the solvent is acetone. The impregnation can be performed by using an equal volume impregnation process. For the palladium salt concentration, the palladium salt solution can be configured according to the palladium loading in the catalyst carrier, which is 0.1-1 wt%. For example, the palladium salt solution is configured according to the palladium loading in the catalyst carrier, which is 0.2 wt%, and after calcination and reduction, the palladium loading of the palladium-containing alumina-based anthraquinone hydrogenation catalyst is 0.2 wt%.

[0024] In another aspect, the present application also provides an alumina-based catalyst for anthraquinone hydrogenation, which uses macromolecular PVP and cyclic polysaccharide small molecules as a composite template for ammonium-aluminum co-precipitation. Not only is an alumina carrier material with high specific surface area prepared, but also the loading capacity for palladium is improved, and the dispersion of palladium is promoted, which is conducive to improving the hydrogenation efficiency.

[0025] Beneficial effects: The macromolecular polyvinylpyrrolidone has repeating structural units, and the repeatability of the structural unit groups can realize directional adsorption of particles, and an alumina material with controllable morphology is prepared; at the same time, a small amount of cyclic polysaccharide small molecules is added as a template and a surfactant. The nitrogen-containing groups and carbonyl groups on the PVP can form hydrogen bonds with the hydroxyl groups on the cyclic polysaccharide small molecules, which not only can improve the dispersion performance of the macromolecular PVP by using the easy solubility of the cyclic polysaccharide small molecules, but also can provide more soft template forms to promote the dispersion of the crystal grains. In addition, by introducing the ring structure of the cyclic polysaccharide small molecules, the disadvantage of poor controllability of the single PVP template can be avoided, and the controllable formation of the alumina carrier is promoted, which is conducive to improving the specific surface area of the alumina carrier. The alumina carrier with high specific surface area has strong loading capacity for palladium, promotes the dispersion of palladium, and is conducive to improving the hydrogenation efficiency. DETAILED DESCRIPTION

[0026] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in combination with specific examples and comparative examples, the purpose of which is to understand the content of the present application in detail, rather than to limit the present application. All other examples obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present application.

[0027] Example 1

[0028] A preparation method of an alumina-based catalyst for anthraquinone hydrogenation, comprising the following steps:

[0029] (1) adding an aluminum salt and PVP into deionized water, 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; in the aluminum salt mixed solution, the concentration of the aluminum salt is 0.2 mol / L; the mass ratio of the PVP to the aluminum salt is 0.1:1;

[0030] (2) adding an ammonium salt and a cyclic polysaccharide small molecule into deionized water, ultrasonic dispersion uniformly, 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 molecule to the PVP in step (1) is 0.25:1; the ammonium salt is ammonium bicarbonate; in the ammonium salt mixed solution, the concentration of the ammonium salt 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;

[0031] (3) adding the aluminum salt mixed solution into the ammonium salt mixed solution dropwise while stirring, after the dropwise addition is completed, aging, suction filtration, drying and calcination to obtain an alumina carrier; the dropwise addition speed of the aluminum salt mixed solution is 12 mL / min; the calcination temperature is 650 ℃, and the calcination time is 6 h;

[0032] (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina carrier 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 configured according to a palladium loading of 0.2 wt% in the alumina carrier;

[0033] (5) drying, calcining and reducing the impregnated alumina carrier to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature is 300 ℃, the calcination time is 4 h; the reduction is performed at 170 ℃ for 3.5 h by using a 10 vol% hydrogen / argon mixed gas.

[0034] Example 2

[0035] A preparation method of an alumina-based catalyst for anthraquinone hydrogenation, comprising the following steps:

[0036] (1) adding an aluminum salt and PVP into deionized water, stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 15000; the aluminum salt is aluminum nitrate; in the aluminum salt mixed solution, the concentration of the aluminum salt is 0.2 mol / L; the mass ratio of the PVP to the aluminum salt is 0.4:1;

[0037] (2) adding an ammonium salt and a cyclic polysaccharide small molecule into deionized water, uniformly dispersing by ultrasonic, 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 molecule 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; and the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin;

[0038] (3) adding the aluminum salt mixed solution into the ammonium salt mixed solution dropwise while stirring, and after the dropwise addition is completed, obtaining an aluminum oxide carrier through aging, suction filtration, drying and calcination; the dropwise addition speed of the aluminum salt mixed solution is 18 mL / min; the calcination temperature is 750°C, and the calcination time is 4 h;

[0039] (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the aluminum oxide carrier 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 configured according to a palladium loading amount of 0.2 wt% in the aluminum oxide carrier;

[0040] (5) obtaining an aluminum oxide-based catalyst for anthraquinone hydrogenation by drying, calcining and reducing the impregnated aluminum oxide carrier; the calcination temperature is 350°C, and the calcination time is 3 h; the reduction is performed at 190°C for 2.5 h by using a 10 vol% hydrogen / argon mixed gas.

[0041] Example 3

[0042] A preparation method of an aluminum oxide-based catalyst for anthraquinone hydrogenation, comprising the following steps:

[0043] (1) adding an aluminum salt and PVP into 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; and the mass ratio of the PVP to the aluminum salt is 0.3:1;

[0044] (2) adding an ammonium salt and a cyclic polysaccharide small molecule into deionized water, uniformly dispersing by ultrasonic, 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 molecule 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; and the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin;

[0045] (3) adding the aluminum salt mixed solution into the ammonium salt mixed solution dropwise while stirring, and after the dropwise addition is completed, obtaining an aluminum oxide carrier through aging, suction filtration, drying and calcination; the dropwise addition speed of the aluminum salt mixed solution is 15 mL / min; the calcination temperature is 710°C, and the calcination time is 5 h;

[0046] (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina carrier 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 according to a palladium loading of 0.2 wt% in the alumina carrier;

[0047] (5) drying, calcining, and reducing the impregnated alumina carrier to obtain an alumina-based catalyst for hydrogenation of anthraquinone; the calcination temperature is 320℃, and the calcination time is 3.5 h; the reduction is performed at 180℃ for 3 h using a 10 vol% hydrogen / argon mixed gas.

[0048] Example 4

[0049] A method for preparing an alumina-based catalyst for hydrogenation of anthraquinone, comprising the following steps:

[0050] (1) adding an aluminum salt and PVP to deionized water, stirring to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 10,000; the aluminum salt is aluminum nitrate; in the aluminum salt mixed solution, the concentration of the aluminum salt is 0.2 mol / L; the mass ratio of the PVP to the aluminum salt is 0.4:1;

[0051] (2) adding an ammonium salt and a cyclic polysaccharide small molecule to deionized water, ultrasonically dispersing to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecule to the PVP in step (1) is 0.5:1; the ammonium salt is ammonium bicarbonate; in the ammonium salt mixed solution, the concentration of the ammonium salt 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;

[0052] (3) adding the aluminum salt mixed solution dropwise into the ammonium salt mixed solution while stirring, and after the addition is completed, aging, suction filtration, drying, and calcination to obtain an alumina carrier; the dropwise addition rate of the aluminum salt mixed solution is 15 mL / min; the calcination temperature is 650℃, and the calcination time is 4 h;

[0053] (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina carrier 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 according to a palladium loading of 0.2 wt% in the alumina carrier;

[0054] (5) drying, calcining, and reducing the impregnated alumina carrier to obtain an alumina-based catalyst for hydrogenation of anthraquinone; the calcination temperature is 300℃, and the calcination time is 3 h; the reduction is performed at 190℃ for 3.5 h using a 10 vol% hydrogen / argon mixed gas.

[0055] Example 5

[0056] A preparation method of an alumina-based catalyst for anthraquinone hydrogenation, comprising the following steps:

[0057] (1) adding an aluminum salt and PVP into deionized water, 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 concentration of the aluminum salt in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of the PVP to the aluminum salt is 0.6:1;

[0058] (2) adding an ammonium salt and a cyclic polysaccharide small molecule into deionized water, ultrasonic dispersion uniformly, 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 molecule to the PVP in step (1) is 0.35:1; the ammonium salt is ammonium bicarbonate; the concentration of the ammonium salt 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;

[0059] (3) adding the aluminum salt mixed solution into the ammonium salt mixed solution dropwise while stirring, after the dropwise addition is completed, aging, suction filtration, drying and calcination to obtain an alumina carrier; the dropwise addition speed of the aluminum salt mixed solution is 15 mL / min; the calcination temperature is 710 ℃, and the calcination time is 5 h;

[0060] (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina carrier 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 configured according to a palladium loading of 0.2 wt% in the alumina carrier;

[0061] (5) drying, calcining and reducing the impregnated alumina carrier to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature is 320 ℃, the calcination time is 3.5 h; the reduction is performed at 180 ℃ for 3 h by using 10 vol% hydrogen / argon mixed gas.

[0062] Example 6

[0063] A preparation method of an alumina-based catalyst for anthraquinone hydrogenation, comprising the following steps:

[0064] (1) adding an aluminum salt and PVP into deionized water, 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 concentration of the aluminum salt in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of the PVP to the aluminum salt is 0.25:1;

[0065] (2) adding an ammonium salt and a cyclic polysaccharide small molecule into deionized water, uniformly dispersing by ultrasonic, 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 molecule 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;

[0066] (3) adding the aluminum salt mixed solution into the ammonium salt mixed solution dropwise while stirring, and after the dropwise addition is completed, obtaining an aluminum oxide carrier by aging, suction filtration, drying and calcination; the dropwise addition rate of the aluminum salt mixed solution is 14 mL / min; the calcination temperature is 680°C, and the calcination time is 5.5 h;

[0067] (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the aluminum oxide carrier 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 configured according to a palladium loading of 0.2 wt% in the aluminum oxide carrier;

[0068] (5) obtaining an aluminum oxide-based catalyst for anthraquinone hydrogenation by drying, calcining and reducing the impregnated aluminum oxide carrier; the calcination temperature is 310°C, and the calcination time is 3.8 h; the reduction is performed by using a 10 vol% hydrogen / argon mixed gas to reduce at 180°C for 3.2 h.

[0069] Example 7

[0070] A preparation method of an aluminum oxide-based catalyst for anthraquinone hydrogenation, comprising the following steps:

[0071] (1) adding an aluminum salt and PVP into 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; and the mass ratio of the PVP to the aluminum salt is 0.3:1;

[0072] (2) adding an ammonium salt and a cyclic polysaccharide small molecule into deionized water, uniformly dispersing by ultrasonic, 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 molecule 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; and the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin;

[0073] (3) adding the aluminum salt mixed solution into the ammonium salt mixed solution dropwise while stirring, and after the dropwise addition is completed, obtaining an aluminum oxide carrier by aging, suction filtration, drying and calcination; the dropwise addition rate of the aluminum salt mixed solution is 15 mL / min; the calcination temperature is 710°C, and the calcination time is 5 h;

[0074] (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina carrier 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 according to a palladium loading of 0.2 wt% in the alumina carrier;

[0075] (5) drying, calcining, and reducing the impregnated alumina carrier to obtain an alumina-based catalyst for hydrogenation of anthraquinone; the calcination temperature is 320°C, and the calcination time is 3.5 h; the reduction is performed at 180°C for 3 h using a 10 vol% hydrogen / argon mixed gas.

[0076] Example 8

[0077] A method for preparing an alumina-based catalyst for hydrogenation of anthraquinone, comprising the following steps:

[0078] (1) adding an aluminum salt and PVP to deionized water, stirring to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 10,000; the aluminum salt is aluminum nitrate; in the aluminum salt mixed solution, the concentration of the aluminum salt is 0.2 mol / L; the mass ratio of the PVP to the aluminum salt is 0.35:1;

[0079] (2) adding an ammonium salt and a cyclic polysaccharide small molecule to deionized water, ultrasonically dispersing to obtain an ammonium salt mixed solution; the mass ratio of the cyclic polysaccharide small molecule to the PVP in step (1) is 0.4:1; the ammonium salt is ammonium bicarbonate; in the ammonium salt mixed solution, the concentration of the ammonium salt 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;

[0080] (3) adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, and after the addition is completed, aging, suction filtration, drying, and calcination to obtain an alumina carrier; the dropwise addition rate of the aluminum salt mixed solution is 16 mL / min; the calcination temperature is 720°C, and the calcination time is 4.5 h;

[0081] (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina carrier 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 according to a palladium loading of 0.2 wt% in the alumina carrier;

[0082] (5) drying, calcining, and reducing the impregnated alumina carrier to obtain an alumina-based catalyst for hydrogenation of anthraquinone; the calcination temperature is 330°C, and the calcination time is 3.4 h; the reduction is performed at 180°C for 3.2 h using a 10 vol% hydrogen / argon mixed gas.

[0083] Example 9

[0084] A preparation method of an alumina-based catalyst for anthraquinone hydrogenation, comprising the following steps:

[0085] (1) adding an aluminum salt and PVP into deionized water, stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 15000; the aluminum salt is aluminum nitrate; the concentration of the aluminum salt in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of the PVP to the aluminum salt is 0.32:1;

[0086] (2) adding an ammonium salt and a cyclic polysaccharide small molecule into deionized water, ultrasonic dispersion uniformly, 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 molecule to the PVP in step (1) is 0.38:1; the ammonium salt is ammonium bicarbonate; the concentration of the ammonium salt 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;

[0087] (3) adding the aluminum salt mixed solution into the ammonium salt mixed solution dropwise while stirring, and after the dropwise addition is completed, aging, suction filtration, drying, and calcination are performed to obtain an alumina carrier; the dropwise addition speed of the aluminum salt mixed solution is 16 mL / min; the calcination temperature is 690℃, and the calcination time is 5.2 h;

[0088] (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina carrier 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 configured according to a palladium loading of 0.2 wt% in the alumina carrier;

[0089] (5) drying, calcining, and reducing the impregnated alumina carrier to obtain an alumina-based catalyst for anthraquinone hydrogenation; the calcination temperature is 325℃, and the calcination time is 3.6 h; the reduction is performed at 180℃ for 2.8 h using a 10 vol% hydrogen / argon mixed gas.

[0090] Example 10

[0091] A preparation method of an alumina-based catalyst for anthraquinone hydrogenation, comprising the following steps:

[0092] (1) adding an aluminum salt and PVP into deionized water, 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 concentration of the aluminum salt in the aluminum salt mixed solution is 0.2 mol / L; the mass ratio of the PVP to the aluminum salt is 0.3:1;

[0093] (2) adding an ammonium salt and a cyclic polysaccharide small molecule into deionized water, uniformly dispersing by ultrasonic, 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 molecule 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;

[0094] (3) adding the aluminum salt mixed solution into the ammonium salt mixed solution dropwise while stirring, and after the dropwise addition is completed, obtaining an aluminum oxide carrier through aging, suction filtration, drying and calcination; the dropwise addition rate of the aluminum salt mixed solution is 15 mL / min; the calcination temperature is 710°C, and the calcination time is 5 h;

[0095] (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the aluminum oxide carrier 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 configured according to a palladium loading amount of 0.2 wt% in the aluminum oxide carrier;

[0096] (5) obtaining an aluminum oxide-based catalyst for anthraquinone hydrogenation by drying, calcining and reducing the impregnated aluminum oxide carrier; the calcination temperature is 320°C, and the calcination time is 3.5 h; the reduction is carried out at 180°C for 3 h by using a 10 vol% hydrogen / argon mixed gas.

[0097] Comparative Example 1

[0098] A preparation method of an aluminum oxide-based catalyst for anthraquinone hydrogenation, comprising the following steps:

[0099] (1) adding an aluminum salt and PVP into deionized water, and stirring uniformly to obtain an aluminum salt mixed solution; the number average molecular weight of the PVP is 20000; 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 the PVP to the aluminum salt is 0.3:1;

[0100] (2) adding an ammonium salt and a cyclic polysaccharide small molecule into deionized water, uniformly dispersing by ultrasonic, 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 molecule 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;

[0101] (3) adding the aluminum salt mixed solution into the ammonium salt mixed solution dropwise while stirring, and after the dropwise addition is completed, obtaining an aluminum oxide carrier through aging, suction filtration, drying and calcination; the dropwise addition rate of the aluminum salt mixed solution is 15 mL / min; the calcination temperature is 710°C, and the calcination time is 5 h;

[0102] (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina carrier 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 according to a palladium loading of 0.2 wt% in the alumina carrier;

[0103] (5) drying, calcining, and reducing the impregnated alumina carrier to obtain an alumina-based catalyst for hydrogenation of anthraquinone; the calcination temperature is 320°C, and the calcination time is 3.5 h; the reduction is performed at 180°C for 3 h using a 10 vol% hydrogen / argon mixed gas.

[0104] Comparative Example 2

[0105] A method for preparing an alumina-based catalyst for hydrogenation of anthraquinone includes the following steps:

[0106] (1) adding an aluminum salt and PVP to deionized water, stirring to obtain an aluminum salt mixed solution; the number-average molecular weight of the PVP is 12000; the aluminum salt is aluminum nitrate; in the aluminum salt mixed solution, the aluminum salt concentration is 0.2 mol / L; the mass ratio of the PVP to the aluminum salt is 0.3:1;

[0107] (2) adding an ammonium salt and a cyclic polysaccharide small molecule to deionized water, ultrasonically dispersing to obtain an ammonium salt mixed solution, and adjusting the solution pH to 9.5; the mass ratio of the cyclic polysaccharide small molecule to the PVP in step (1) is 1:1; 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 8:1; the cyclic polysaccharide small molecule is hydroxypropyl-β-cyclodextrin;

[0108] (3) adding the aluminum salt mixed solution dropwise to the ammonium salt mixed solution while stirring, and after the dropwise addition is completed, aging, suction filtration, drying, and calcination to obtain an alumina carrier; the dropwise addition rate of the aluminum salt mixed solution is 15 mL / min; the calcination temperature is 710°C, and the calcination time is 5 h;

[0109] (4) dispersing a palladium salt in a solvent to obtain a palladium salt solution, and then impregnating the alumina carrier 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 according to a palladium loading of 0.2 wt% in the alumina carrier;

[0110] (5) drying, calcining, and reducing the impregnated alumina carrier to obtain an alumina-based catalyst for hydrogenation of anthraquinone; the calcination temperature is 320°C, and the calcination time is 3.5 h; the reduction is performed at 180°C for 3 h using a 10 vol% hydrogen / argon mixed gas.

[0111] The performance of the alumina carriers prepared in Examples 1-10 and Comparative Examples 1-2 was tested by a gas adsorption method (BET) to measure the specific surface area (m 2 / g), pore size (nm), as shown in Tables 1-2.

[0112] The performance of the alumina-based catalysts for hydrogenation of anthraquinone prepared in Examples 1-10 and Comparative Examples 1-2 was tested as follows. 2-ethylanthraquinone was dissolved in a mixed solvent of mesitylene and tricaprylyl phosphate (volume ratio of mesitylene to tricaprylyl phosphate was 1:1) 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 taken and added to a reactor, and high-purity hydrogen was used as the raw material. The reaction temperature was set to 60°C, the reaction pressure was set to 0.3 MPa, and the reaction time was set to 90 min. The working solution after the reaction was passed through oxygen for oxidation, and the hydrogen peroxide content in the working solution was analyzed by titration with potassium permanganate solution to calculate the hydrogenation efficiency (g / L), as shown in Tables 1-2.

[0113] Table 1 Alumina carriers prepared in Examples 1-6

[0114] and the performance of the alumina-based catalysts for hydrogenation of anthraquinone

[0115]

[0116] Table 2 Alumina carriers prepared in Examples 7-10 and Comparative Examples 1-2

[0117] and the performance of the alumina-based catalysts for hydrogenation of anthraquinone

[0118]

[0119] As can be seen from Tables 1 and 2, the present application uses macromolecular polyvinylpyrrolidone as the main template agent, and adds a small amount of cyclic polysaccharide small molecules as auxiliary template agents 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 characteristics of the cyclic polysaccharide small molecules be used to improve the dispersion performance of the macromolecular PVP, but also can provide more soft template forms to promote the dispersion of the crystal grains. In addition, by introducing the ring structure of the cyclic polysaccharide small molecules, the shortcomings of poor controllability of single PVP template agent can be avoided, the controllable formation of the alumina carrier is promoted, and the specific surface area of the alumina carrier is improved. The alumina carrier with high specific surface area has strong loading capacity for palladium, promotes the dispersion of palladium, and is beneficial to the improvement of hydrogenation efficiency.

[0120] Compared with Example 10, the PVP in Comparative Example 1 has too large molecular weight, the molecular chain movement is difficult, the template effect and the surfactant effect are reduced, the specific surface area of the prepared alumina carrier is reduced, the dispersion of the active palladium is not good, and the hydrogenation efficiency is reduced.

[0121] Compared with Example 10, the hydroxypropyl-β-cyclodextrin cyclic polysaccharide small molecule added in Comparative Example 2 is too much, which is not good for the stability of the PVP micelle structure and the stability of the porous structure in the calcination process, affects the formation of the pore size of the alumina carrier, and reduces the catalytic activity.

[0122] Obviously, the above examples of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description, and it is impossible to enumerate all the embodiments here. Any changes or variations derived from the technical solutions of the present application still fall within the protection scope of the present application.

Claims

1. A method for preparing an alumina-based catalyst for anthraquinone hydrogenation, characterized in that: The following steps are involved: (1) Add aluminum salt and PVP to deionized water and stir evenly to obtain an aluminum salt mixed solution; (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) drying, calcining, and reducing the alumina support impregnated in step (4) to obtain an alumina-based catalyst for anthraquinone hydrogenation; 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; The cyclic polysaccharide small molecule in step (2) is cyclodextrin and its derivatives; 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.

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 in the aluminum salt mixed solution, the aluminum salt concentration is 0.1-0.5 mol / L.

3. 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.

4. 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.

5. 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.

6. 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.

7. 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 6.

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