Method for preparing alumina carrier and alumina-based catalyst and application of catalyst

Abstract

The invention relates to a method for preparing an alumina carrier and an alumina-based catalyst and application of the catalyst, and the method comprises the following steps: S1, carrying out a first contact reaction on molded alumina and a treating fluid to obtain a first product; s2, carrying out second contact reaction on the first product and a solution containing a structure inducer; s3, carrying out aging treatment on a mixture obtained by the second contact reaction; the treating fluid is an acidic solution or an alkaline solution; the structure-directing agent comprises one or more of sulfonate with the carbon atom number of 10-18, alkyl trimethyl ammonium salt with the carbon atom number of 10-20, ethylene glycol or polyethylene glycol; according to the method disclosed by the invention, the alumina carrier with an external pore structure and a high specific surface area can be prepared, and the catalyst prepared by using the alumina carrier has an eggshell-shaped structure and has the advantages of high dispersion degree of active components, relatively low mass and heat transfer resistance and the like.

Description

Technical Field

[0001] The present disclosure relates to the field of eggshell-type catalyst preparation, and in particular, to a method for preparing an alumina carrier and an alumina-based catalyst, and applications of the catalyst. Background Art

[0002] Supported catalysts occupy a crucial position in the chemical industry, currently employing approximately 90% of chemical catalytic processes. Among the numerous supported catalysts, those based on shaped alumina (e.g., strips, spheres, honeycombs) are widely used in the chemical industry, particularly in the petrochemical and fine chemical sectors, due to their low cost, ease of separation, and high reusability. While the relatively uniform pore size distribution of alumina materials ensures the proper functioning of most reactions, the relatively uniform pore size of the shaped support can limit catalytic performance for reactions with significant mass and heat transfer limitations. For example, the selective hydrogenation of acetylene to ethylene, a crucial step in the ethylene industry, is a crucial step. As a typical exothermic continuous hydrogenation reaction, this industrial reaction typically utilizes supports with narrow pore sizes of 2-10 nm. While this small, concentrated pore size ensures highly dispersed and uniform distribution of the loaded precious metal, its unique pore structure also limits the diffusion of reaction heat, a particularly pronounced effect for conventional spherical alumina supports. Under the condition of limited heat transfer, the ethylene obtained by acetylene hydrogenation will be competitively adsorbed with alkynes on the catalytic active centers, resulting in further hydrogenation of ethylene and resulting in product loss. At the same time, the accumulation of heat on the active centers can cause the polymerization reaction to generate green oil, reduce the selectivity of olefins and poison the catalyst. Similarly, for the typical mass transfer limited reaction of selective hydrogenation of anthraquinone to prepare hydrogen peroxide, a carrier with a small pore size and concentrated distribution limits the diffusion of the reaction products, resulting in further hydrogenation of the hydroanthraquinone generated by anthraquinone hydrogenation, generating degradation products that cannot produce hydrogen peroxide, thereby resulting in a reduction in hydrogen peroxide production, causing serious economic losses. For other reactions with limited mass transfer and heat transfer in the fine chemical and petrochemical fields, there is also a common problem that the catalytic performance caused by the poor structure of the molded alumina carrier needs to be improved. Therefore, there is an urgent need to develop a molded alumina carrier with a suitable structure to reduce mass transfer and heat transfer resistance while achieving uniform and highly dispersed active components.

[0003] In order to avoid the negative impact of the large mass transfer and heat transfer resistance of shaped alumina-supported catalysts, researchers usually adopt a method of controlling the depth of active metal loading in the shaped carrier, by shortening the diffusion distance of the reaction products and reaction heat in the catalyst pores, to achieve the enhancement of the catalyst mass transfer and heat transfer effect. Chou et al. reported in Selective hydrogenation of isoprene overδ-alumina-supported eggshell Pd catalysts:Particle size effect.Applied Catalysis A:General 1997,156,193 that compared with catalysts with thicker shell thickness, catalysts with thinner shell thickness showed lower mass transfer resistance. However, under the same active metal loading, catalysts with thicker shell thickness have higher active metal dispersion, while catalysts with thinner shell thickness have lower active metal dispersion. Therefore, under the dual effects of active metal dispersion and mass transfer effect, catalysts with moderate shell thickness showed the best performance. Liu Chenguang and others from China University of Petroleum have achieved control over the depth of active metal loading in the catalyst by controlling the calcination temperature of the spherical alumina carrier. When the calcination temperature is increased from 700°C to 1000°C, the shell thickness increases from 63μm to 1000μm. However, as the calcination temperature increases, the specific surface area of ​​the carrier decreases significantly, and the dispersion of the active metal decreases significantly, leading to a decrease in catalytic activity. From the above research, it is not difficult to see that catalysts prepared by traditional methods are difficult to achieve while ensuring uniform and highly dispersed active components and reducing mass transfer and heat transfer resistance. In other words, it is difficult to achieve the optimization of the shell pore structure and the increase of active metal adsorption sites by traditional means. Summary of the Invention

[0004] The purpose of the present disclosure is to provide a method for preparing an alumina carrier and an alumina-based catalyst and the application of the catalyst. The alumina-based catalyst can have the characteristics of high dispersion of active components and low mass and heat transfer resistance.

[0005] In order to achieve the above objectives, the present disclosure provides a first aspect of a method for preparing an alumina carrier, the method comprising the following steps:

[0006] S1, performing a first contact reaction between the formed alumina and the treatment liquid to obtain a first product;

[0007] S2, subjecting the first product to a second contact reaction with a solution containing a structure-inducing agent;

[0008] S3, subjecting the mixture obtained from the second contact reaction to an aging treatment;

[0009] The treatment liquid is an acidic solution or an alkaline solution;

[0010] The structure directing agent includes one or more of sulfonates with 10-18 carbon atoms, alkyltrimethylammonium salts with 10-20 carbon atoms, ethylene glycol or polyethylene glycol.

[0011] Optionally, in step S1, the first contact reaction is carried out in stages under ultrasonic conditions, and after each stage of reaction, the solid is washed until the washed liquid is neutral before the next stage of reaction is carried out;

[0012] The reaction time of each stage is 10s-120min, the reaction temperature of each stage is 25-100°C, and the number of stages is any integer from 1 to 50;

[0013] Optionally, step S1 further comprises: performing a first drying treatment on the solid obtained by the first contact reaction;

[0014] The conditions of the first drying treatment include: a temperature of 50-200° C. and a time of 8-36 hours.

[0015] Optionally, the acidic solution includes a hydrochloric acid solution and / or a nitric acid solution, and the pH value of the acidic solution is 3-5;

[0016] The alkaline solution includes sodium hydroxide solution and / or potassium hydroxide solution, and the pH value of the alkaline solution is 9-12;

[0017] The volume ratio of the dense packing volume of the shaped alumina to the treatment liquid used in each stage of the first contact reaction is 1:(1.2-10).

[0018] Optionally, in step S2, the structure inducing agent includes one or more of sodium hexadecyl sulfonate, sodium dodecyl sulfonate, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, ethylene glycol and polyethylene glycol;

[0019] The molar ratio of the structural inducing agent to the shaped alumina calculated as aluminum element is (0.004-0.05):1;

[0020] The second contact reaction is carried out under ultrasonic conditions for 10-120 minutes at a temperature of 25-80°C.

[0021] Optionally, in step S3, the aging treatment conditions include: a time of 4-48 hours and a temperature of 80-180°C;

[0022] The method further comprises: sequentially subjecting the solid obtained from the aging treatment to a washing treatment, a second drying treatment, and a heat treatment;

[0023] The conditions of the second drying treatment include: a time of 8-72 hours and a temperature of 100-180°C;

[0024] The heat treatment method includes roasting, and the conditions include: time is 4-10 hours, and temperature is 400-1200°C.

[0025] A second aspect of the present disclosure provides an alumina carrier prepared by the method described in the first aspect of the present disclosure.

[0026] Optionally, the specific surface area of ​​the alumina carrier is 100-350m 2 / g, pore volume of 0.40-1.20cm 3 / g, and pores with a pore diameter of 8-20 nm account for more than 80% of the total pore volume.

[0027] The third aspect of the present disclosure provides a method for preparing an alumina-based catalyst, the method comprising: subjecting the alumina support described in the second aspect of the present disclosure to a third contact reaction with a solution containing an active metal source;

[0028] The active metal source includes one or more of a palladium source, a platinum source, a gold source, an iridium source, a ruthenium source, a silver source, a copper source and a cobalt source.

[0029] Optionally, the active metal source includes one or more of nitrates, chlorine-containing compounds and acetylacetonate;

[0030] In the solution containing the active metal source, the concentration of the active metal source is 1-100 mmol / L;

[0031] The amount of the active metal source calculated as metal element is 0.1-10 wt % relative to the total weight of the alumina support.

[0032] Optionally, the third contact reaction is carried out under stirring conditions, with a rotation speed of 100-500 rpm, a time of 0.5-6 h, and a temperature of 25-80°C.

[0033] Optionally, the method further comprises: subjecting the solid obtained from the third contact reaction to a third drying treatment, wherein the conditions of the third drying treatment include: a temperature of 100-180° C. and a time of 8-72 hours;

[0034] Optionally, the method further comprises: performing a reduction treatment on the pre-product obtained by the third drying treatment;

[0035] The reduction treatment is carried out in a hydrogen atmosphere at a temperature of 80-500° C. for 0.5-8 h.

[0036] The hydrogen-containing atmosphere includes a hydrogen atmosphere or a hydrogen-nitrogen atmosphere, and the hydrogen content in the hydrogen-nitrogen atmosphere is 10-50% by volume.

[0037] A fourth aspect of the present disclosure provides an alumina-based catalyst prepared by the method described in the third aspect of the present disclosure.

[0038] Optionally, the alumina-based catalyst comprises an alumina carrier and a metal active component, and the dispersion degree of the metal active component is 70-99%.

[0039] The fifth aspect of the present disclosure provides a hydrogenation reaction, comprising contacting a material to be hydrogenated, hydrogen and a catalyst for reaction, wherein the catalyst comprises the alumina-based catalyst described in the fourth aspect of the present application.

[0040] Optionally, the material to be hydrogenated includes one of anthraquinone and an olefin having 2 to 6 carbon atoms.

[0041] Optionally, the material to be hydrogenated is anthraquinone, the temperature of the hydrogenation reaction is 40-80°C, the pressure is 0.1-1.2 MPa, the molar ratio of the hydrogen to the material to be hydrogenated is (4-200):1, and the weight ratio of the metal active component in the catalyst calculated as metal element to the raw material to be hydrogenated is 1:(8-1200).

[0042] Optionally, the material to be hydrogenated is olefin, the temperature of the hydrogenation reaction is 100-300°C, the pressure is 0.1-1.2 MPa, the molar ratio of hydrogen to the material to be hydrogenated is (2-100):1, and the reaction space velocity is 5000-12000h -1 .

[0043] Through the above technical solution, the present invention, based on the amphoteric characteristics and array structure characteristics of alumina, uses an acidic solution or an alkaline solution to etch the formed alumina, so that at least part of the aluminum atoms on the surface and in the pores of the alumina are dissolved, thereby widening the pore structure and exposing more coordinatively unsaturated sites; then, through a structural inducer and subsequent treatment, the dissolved aluminum ions are caused to form needle-shaped alumina clusters on the surface and in the pores of the alumina, thereby obtaining an alumina carrier with an external open pore structure and a high specific surface area; the method of the present invention can achieve the regulation of the external open pore structure by controlling the condition parameters of each step; the catalyst prepared using the above-mentioned alumina carrier has an eggshell-type structure, and has the advantages of high dispersion of active components and low mass and heat transfer resistance.

[0044] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0046] Figure 1 XRD spectra of the alumina supports prepared in Examples 1 and 2 of the present disclosure.

[0047] Figure 2 The pore size distribution curves of the alumina supports prepared in Example 3 and Comparative Example 2 of the present disclosure are shown.

[0048] Figure 3 This is an SEM image of the alumina support prepared in Example 5 of the present disclosure.

[0049] Figure 4 This is a cross-sectional view of catalyst A1 prepared in Example 5 of the present disclosure. DETAILED DESCRIPTION

[0050] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0051] A first aspect of the present disclosure provides a method for preparing an alumina support, the method comprising the following steps:

[0052] S1, performing a first contact reaction between the formed alumina and the treatment liquid to obtain a first product;

[0053] S2, subjecting the first product to a second contact reaction with a solution containing a structure-inducing agent;

[0054] S3, subjecting the mixture obtained from the second contact reaction to an aging treatment;

[0055] The treatment liquid is an acidic solution or an alkaline solution;

[0056] The structure directing agent includes one or more of sulfonates with 10-18 carbon atoms, alkyltrimethylammonium salts with 10-20 carbon atoms, ethylene glycol or polyethylene glycol.

[0057] In the present disclosure, the weight average molecular weight of polyethylene glycol is 400-1500.

[0058] The method disclosed herein etches the formed alumina with an acidic or alkaline solution, dissolving at least some of the aluminum atoms on the surface and in the pores of the alumina, thereby widening the pore structure and exposing more coordinatively unsaturated sites. A structural inducing agent and subsequent aging treatment are then used to cause the dissolved aluminum ions to form needle-shaped alumina clusters on the surface and in the pores of the alumina, thereby obtaining an alumina carrier with an externally open pore structure. The method disclosed herein can achieve regulation of the externally open pore structure by controlling the condition parameters of each step. The above-mentioned alumina carrier can be used to prepare a catalyst with an eggshell-shaped structure, which has the advantages of high dispersion of active components and low mass and heat transfer resistance.

[0059] In the present disclosure, the shaped alumina is conventional in the art and may be in the shape of a bar, a sphere, an O-shape or a four-leaf clover. The present disclosure does not limit the parameters such as the forming method and shape of the shaped alumina.

[0060] In the present disclosure, unless otherwise specified, pH values ​​are values ​​measured at 25° C. and standard atmospheric pressure.

[0061] According to one embodiment of the present disclosure, the acidic solution includes a hydrochloric acid solution and / or a nitric acid solution, and the pH value of the acidic solution is 3-5. When the acidic solution includes a hydrochloric acid solution and a nitric acid solution, there is no specific restriction on the ratio between the two. The alkaline solution includes a sodium hydroxide solution and / or a potassium hydroxide solution, and the pH value of the alkaline solution is 9-12. When the alkaline solution includes a sodium hydroxide solution and a potassium hydroxide solution, there is no specific restriction on the ratio between the two.

[0062] In order to dissolve at least part of the aluminum atoms on the surface and in the pores of alumina to provide sites for the growth of alumina clusters, according to one embodiment of the present disclosure, the volume ratio of the dense packing volume of the shaped alumina to the treatment liquid used in each first contact reaction is 1:(1.2-10), preferably 1:(2-5), wherein the "dense packing volume" refers to the volume when the shaped alumina reaches the densest packing.

[0063] In order to make the treatment liquid treatment more uniform and sufficient, according to one embodiment of the present disclosure, in step S1, the first contact reaction is carried out in stages under ultrasonic conditions, and the time of each reaction is 10s-120min, preferably 30s-30min, and the temperature of each reaction is 25-100°C, preferably 25-80°C. The number of stages is any integer from 1 to 50, preferably 3-5; the time of each stage is the same or different, preferably the same; the temperature of each stage is the same or different, preferably the same; after each reaction, the solid is washed until the washed liquid is neutral, and then the next reaction is carried out; after each reaction, a new treatment liquid is replaced, and the type and volume of the treatment liquid used in each reaction are preferably the same.

[0064] According to one embodiment of the present disclosure, step S1 also includes: subjecting the solid obtained from the first contact reaction to a first drying treatment, and the method for separating the solid from the mixture obtained from the first contact reaction can be, for example, filtration; the conditions for the first drying treatment include: a temperature of 50-200°C and a time of 8-36h; the method of the first drying treatment is conventional in the art and is not specifically required by the present disclosure.

[0065] According to one embodiment of the present disclosure, the structure-inducing agent includes one or more of sodium cetyl sulfate, sodium dodecyl sulfate, cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, ethylene glycol, and polyethylene glycol. The present disclosure does not impose any specific restrictions on the concentration of the solution containing the structure-inducing agent, and for example, it can be 5-50 mol / L. When there are two or more structure-inducing agents, their ratio is not limited.

[0066] In order to obtain a more uniform growth effect of alumina clusters, according to one embodiment of the present disclosure, the molar ratio of the structure inducer to the formed alumina is (0.004-0.05):1, preferably (0.01-0.04):1.

[0067] According to one embodiment of the present disclosure, the second contact reaction is carried out under ultrasonic conditions for 10-120 minutes at a temperature of 25-80°C.

[0068] According to one embodiment of the present disclosure, in step S3, the aging treatment can be performed in a heat-resistant autoclave, and the aging treatment conditions include: time of 4-48 hours, temperature of 80-180° C., and pressure of the autogenous pressure of the reactor.

[0069] According to one embodiment of the present disclosure, the method further includes: sequentially subjecting the solid obtained by the aging treatment to a washing treatment, a second drying treatment, and a heat treatment; wherein the solid can be separated from the mixture obtained by the aging treatment by, for example, filtration; and the washing treatment includes: washing the solid with deionized water until the washed liquid is neutral.

[0070] According to one embodiment of the present disclosure, the conditions for the second drying treatment include: a time of 8-72 hours and a temperature of 100-180° C.; the method of the second drying treatment is conventional in the art.

[0071] According to one embodiment of the present disclosure, the heat treatment method can be, for example, calcination. The calcination method is conventional in the art, and the heat treatment conditions include: a time of 4-10 hours and a temperature of 400-1200°C. Heat treatment under the above conditions can transform the surface crystal clusters into an alumina material similar to the carrier crystal form, which is beneficial to further improve the performance of the catalyst.

[0072] A second aspect of the present disclosure provides an alumina carrier prepared by the method described in the first aspect of the present disclosure.

[0073] According to one embodiment of the present disclosure, the specific surface area of ​​the alumina carrier is 100-350m 2 / g, pore volume of 0.40-1.20cm 3 / g, and pores with a pore diameter of 8-20 nm account for more than 80% of the total pore volume.

[0074] In the present disclosure, the alumina carrier has an external open pore structure, and the "external open pore structure" refers to having macropores or mesopores with an outward open pore structure; according to the pore structure distribution test, it has external open pores with a pore diameter of more than 10 nm.

[0075] The third aspect of the present disclosure provides a method for preparing an alumina-based catalyst, the method comprising: subjecting the alumina support described in the second aspect of the present disclosure to a third contact reaction with a solution containing an active metal source;

[0076] The active metal source includes one or more of a palladium source, a platinum source, a gold source, an iridium source, a ruthenium source, a silver source, a copper source and a cobalt source.

[0077] According to one embodiment of the present disclosure, the active metal source includes a soluble compound containing an active metal element, preferably including one or more of a nitrate, a chlorine-containing compound, and an acetylacetonate; for example, the active metal source may include palladium chloride, palladium nitrate, cobalt nitrate, cobalt chloride, silver nitrate, copper nitrate, copper chloride, chloroplatinic acid, etc. When there are two or more active metal sources, there is no limit on their ratio.

[0078] According to one embodiment of the present disclosure, in the solution containing the active metal source, the concentration of the active metal source is 1-100 mmol / L, preferably 50-100 mmol / L.

[0079] To ensure the dispersion of the active metal, according to one embodiment of the present disclosure, the amount of the active metal source calculated as the metal element is 0.1-10 wt %, preferably 0.3-5 wt %, relative to the total weight of the alumina support.

[0080] According to one embodiment of the present disclosure, the third contact reaction is carried out under stirring conditions, with a rotation speed of 100-500 rpm, a time of 0.5-6 h, and a temperature of 25-80°C.

[0081] According to one embodiment of the present disclosure, the method further includes: subjecting the solid obtained from the third contact reaction to a third drying treatment, and the method for separating the solid from the mixture obtained from the third contact reaction can be, for example, filtration, and the conditions of the third drying treatment include: a temperature of 100-180°C and a time of 8-72h; the method of the third drying treatment is conventional in the art and is not specifically required by the present disclosure.

[0082] According to one embodiment of the present disclosure, the method further includes: subjecting the pre-product obtained by the third drying process to a reduction treatment; the reduction treatment is performed in a hydrogen-containing atmosphere at a temperature of 80-500° C. for 0.5-8 hours. The hydrogen-containing atmosphere includes a hydrogen atmosphere or a hydrogen-nitrogen atmosphere, and the hydrogen content in the hydrogen-nitrogen atmosphere is 10-50% by volume, preferably 20-50% by volume.

[0083] A fourth aspect of the present disclosure provides an alumina-based catalyst prepared by the method described in the third aspect of the present disclosure.

[0084] According to one embodiment of the present disclosure, the alumina-based catalyst includes an alumina carrier and a metal active component, and the dispersion degree of the metal active component is 70-99%, preferably 80-95%.

[0085] The fifth aspect of the present disclosure provides a hydrogenation reaction, comprising contacting a material to be hydrogenated, hydrogen and a catalyst for reaction, wherein the catalyst comprises the alumina-based catalyst described in the fourth aspect of the present disclosure.

[0086] According to one embodiment of the present disclosure, the material to be hydrogenated includes anthraquinone and one of an olefin having 2 to 6 carbon atoms, wherein the olefin may be, for example, ethylene.

[0087] In order to obtain higher reaction activity, according to one embodiment of the present disclosure, the material to be hydrogenated is anthraquinone, the temperature of the hydrogenation reaction is 40-80°C, the pressure is 0.1-1.2 MPa, the molar ratio of hydrogen to the material to be hydrogenated is (4-200):1, and the weight ratio of the metal active component in the catalyst calculated as metal element to the raw material to be hydrogenated is 1:(8-1200).

[0088] In order to obtain higher reaction activity, according to one embodiment of the present disclosure, the material to be hydrogenated is olefin, the temperature of the hydrogenation reaction is 100-300°C, the pressure is 0.1-1.2 MPa, the molar ratio of hydrogen to the material to be hydrogenated is (2-100):1, and the reaction space velocity is 5000-12000h -1 , reaction space velocity = volume flow rate of material to be hydrogenated (20℃, m 3 / h) / catalyst volume (m 3 ).

[0089] The present disclosure is further illustrated below by way of examples, but the present disclosure is not limited thereby. Unless otherwise specified, the raw materials, reagents, instruments and equipment designed in the examples of the present disclosure can all be purchased.

[0090] The test methods involved in this disclosure are as follows:

[0091] The test method for specific surface area, pore volume, pore distribution and nitrogen adsorption-desorption curve is as follows: 2 g of the sample was weighed and placed in a sample tube, degassed in a nitrogen atmosphere at 120°C for 6 hours, and then the specific surface area, pore volume, pore volume, pore distribution and physical adsorption curve of the material were measured using a Micromeritics ASAP 2020M+C fully automatic physical adsorption and chemical adsorption analyzer.

[0092] XRD test method and conditions: All samples to be tested were ground into powder, lightly pressed into pellets, and then XRD tested in a Shimadzu XRD-6000 machine;

[0093] Test conditions: 40 kV, 30 mA, emission source Cu Kα (λ = 0.154 nm), scanning range 3-70°, step length 10° min -1 .

[0094] SEM testing method: The sample to be tested was fixed on the sample stage with conductive glue, and the surface morphology was tested in a Hitachi Model S-4700 apparatus.

[0095] Dispersion test method: Grind the sample to be tested into a powder, disperse it in an ethanol solution to form a uniform transparent solution, and then add 1-2 drops onto the micro-grid carbon film. After the ethanol has completely evaporated, observe the particle size and calculate the particle size distribution using a JEOL JEM-2100F high-resolution electron microscope. The active ingredient dispersion is calculated based on the spherical particle model: dispersion (%) = 3M / 2N. A Rρσ×100%. Where M is the molecular weight of the active metal (unit: g), N A is Avogadro's constant, R is the average particle diameter (unit: m) obtained by high-resolution electron microscopy, and ρ is the average density of the active metal (unit: g / m 3 ), σ is the average cross-sectional area of ​​active metal atoms (unit: m 2 ).

[0096] To test for bulk volume, accurately weigh 10g of sample into a 25mL graduated cylinder. Place the cylinder on a soft surface and vibrate it 50, 100, 150, 200 times, and so on. Record the volumes after the vibrations (V50, V100, V150, V200, and so on) until the difference between the two most recent recorded volumes is less than 1mL. The bulk volume can be calculated using the formula: bulk volume = mass / volume.

[0097] Example 1

[0098] Preparation of alumina-based catalyst A1:

[0099] A. Under ultrasonic conditions, 10 g of spherical alumina was subjected to a first contact reaction with a hydrochloric acid solution having a pH of 3.5;

[0100] The first contact reaction was carried out in three stages, each lasting 30 seconds at a temperature of 25°C and with a treatment liquid volume of 20 mL. After each stage, the solid was washed until the washed liquid was neutral.

[0101] The volume ratio of the dense packing volume of spherical alumina to the hydrochloric acid solution is 1:2;

[0102] B. drying the solid obtained in step A at 120° C. for 12 h to obtain the first product;

[0103] C. The first product was added to 20 mL of a solution containing 0.49 mol of polyethylene glycol (molecular weight, 800) (the concentration of the structure-directing agent was 24.5 mol / L), and ultrasonicated at 50°C for 60 min to obtain a mixed system;

[0104] The molar ratio of polyethylene glycol to spherical alumina calculated on the basis of aluminum atoms is 0.01:1;

[0105] D. Transfer the mixed system obtained in step C to a temperature-resistant high-pressure hydrothermal autoclave and age it at 120° C. for 8 h;

[0106] After the aging treatment is completed, the mixture is filtered to obtain a solid, and the solid is washed until the washed liquid is neutral;

[0107] The solid was dried at 120°C for 12 h and then calcined at 560°C for 4 h to obtain alumina support A-1, the parameters of which are listed in Table 1;

[0108] E. dissolving palladium chloride in deionized water to prepare a solution containing an active metal source at a concentration of 50 mmol / L;

[0109] F. Add the alumina support A-1 to the solution containing the active metal source in step E and adsorb at a rotation speed of 200 rpm and a temperature of 50° C. for 2 h. After adsorption, filter the solid and dry it at 120° C. for 12 h.

[0110] The amount of palladium chloride used, calculated as palladium element, is 0.5 wt % relative to the total weight of the alumina support;

[0111] G. The solid obtained in step F was reduced at 200° C. in a H 2 atmosphere for 4 h to obtain an alumina-based catalyst A1. The parameters are listed in Table 1.

[0112] Example 2

[0113] Preparation of alumina-based catalyst A2:

[0114] A. Under ultrasonic conditions, 10 g of strip-shaped alumina was subjected to a first contact reaction with a nitric acid solution having a pH of 4;

[0115] The first contact reaction was carried out in four stages, each lasting 30 seconds at a temperature of 50°C and with a treatment liquid volume of 50 mL. After each stage, the solid was washed until the washed liquid was neutral.

[0116] The volume ratio of the close-packed volume of strip-shaped alumina to the volume of the nitric acid solution is 1:1.5;

[0117] B. drying the solid obtained in step A at 120° C. for 12 h to obtain the first product;

[0118] C. The first product was added to 20 mL of a solution containing 0.49 mol of hexadecyltrimethylammonium bromide (the concentration of the structure-directing agent was 24.5 mol / L), and ultrasonicated at 40° C. for 60 min to obtain a mixed system;

[0119] The molar ratio of hexadecyltrimethylammonium bromide to the strip-shaped aluminum oxide calculated on the basis of aluminum atoms is 0.008:1;

[0120] D. Transfer the mixed system obtained in step C to a temperature-resistant autoclave and age it at 180° C. for 6 h;

[0121] After the aging treatment is completed, the mixture is filtered to obtain a solid, and the solid is washed until the washed liquid is neutral;

[0122] The solid was dried at 120°C for 12 h and then calcined at 560°C for 4 h to obtain alumina support A-2. The parameters are listed in Table 1.

[0123] E. dissolving chloropalladic acid in deionized water to prepare a solution containing an active metal source at a concentration of 20 mmol / L;

[0124] F. Add the alumina support A-2 to the solution of step E and adsorb for 2 h at a rotation speed of 200 rpm and a temperature of 50° C. After adsorption, filter the solid and dry it at 120° C. for 12 h;

[0125] The amount of chloropalladic acid used, calculated as palladium element, is 0.25 wt % relative to the total weight of the alumina support;

[0126] G. The solid obtained in step F was reduced at 450° C. in a H 2 / N 2 atmosphere (hydrogen content was 20 vol %) for 4 h to obtain an alumina-based catalyst A2. The parameters are listed in Table 1.

[0127] Example 3

[0128] Preparation of alumina-based catalyst A3:

[0129] A. Under ultrasonic conditions, 15 g of strip-shaped aluminum oxide was subjected to a first contact reaction with a sodium hydroxide solution having a pH of 12;

[0130] The first contact reaction was carried out in three stages, each lasting 2 minutes at a temperature of 25°C and with a treatment liquid volume of 80 mL. After each stage, the solid was washed until the washed liquid was neutral.

[0131] The volume ratio of the dense packing volume of the strip-shaped alumina to the volume of the sodium hydroxide solution is 1:5;

[0132] B. drying the solid obtained in step A at 120° C. for 24 h to obtain the first product;

[0133] C. The first product was added to 25 mL of a solution containing 0.4 mol of hexadecyltrimethylammonium bromide and 0.3 mol of sodium dodecylsulfonate (the concentration of the structure-directing agent was 28 mol / L), and ultrasonicated at 45° C. for 120 min to obtain a mixed system;

[0134] The molar ratio of the total moles of hexadecyltrimethylammonium bromide and sodium dodecylsulfonate to the strip-shaped alumina calculated as aluminum atoms is 0.02:1;

[0135] D. Transfer the mixed system obtained in step C to a temperature-resistant autoclave and age it at 120° C. for 4 h;

[0136] After the aging treatment is completed, the mixture is filtered to obtain a solid, and the solid is washed until the washed liquid is neutral;

[0137] The solid was dried at 120°C for 12 h and then calcined at 600°C for 4 h to obtain alumina support A-3, the parameters of which are listed in Table 1;

[0138] E. dissolving palladium chloride and silver nitrate in deionized water at a molar ratio of 1:1 to prepare a solution containing an active metal source at a concentration of 50 mmol / L;

[0139] F. Add the alumina support A-3 to the solution of step E and adsorb at a rotation speed of 400 rpm and a temperature of 50° C. for 4 hours. After adsorption, filter the solid and dry it at 120° C. for 25 hours.

[0140] The total amount of palladium chloride calculated as palladium element and silver nitrate calculated as silver element is 1 wt % relative to the total weight of the alumina support;

[0141] G. The solid obtained in step F was reduced at 500° C. in a H 2 / N 2 atmosphere (hydrogen content of 20 vol %) for 4 h to obtain an alumina-based catalyst A3. The parameters are listed in Table 1.

[0142] Example 4

[0143] Preparation of alumina-based catalyst A4:

[0144] A. Under ultrasonic conditions, 15 g of strip-shaped aluminum oxide was subjected to a first contact reaction with a sodium hydroxide solution having a pH of 12;

[0145] The first contact reaction was carried out in three stages, each lasting 1.5 min at 25°C, with a treatment liquid volume of 80 mL. After each stage, the solid was washed until the washed liquid was neutral.

[0146] The volume ratio of the close-packed volume of the strip-shaped alumina to the volume of the sodium hydroxide solution is 1:2;

[0147] B. drying the solid obtained in step A at 120° C. for 24 h to obtain the first product;

[0148] C. The first product was added to 25 mL of a solution containing 0.4 mol of hexadecyltrimethylammonium bromide and 0.3 mol of sodium dodecylsulfonate (the concentration of the structure-directing agent was 28 mol / L), and ultrasonicated at 50° C. for 120 min to obtain a mixed system;

[0149] The molar ratio of the total moles of hexadecyltrimethylammonium bromide and sodium dodecylsulfonate to the strip-shaped alumina calculated as aluminum atoms is 0.04:1;

[0150] D. Transfer the mixed system obtained in step C to a temperature-resistant autoclave and age it at 120° C. for 10 h;

[0151] After the aging treatment is completed, the mixture is filtered to obtain a solid, and the solid is washed until the washed liquid is neutral;

[0152] The solid was dried at 120°C for 12 h and then calcined at 600°C for 4 h to obtain alumina support A-4, the parameters of which are listed in Table 1;

[0153] E. dissolving palladium chloride and silver nitrate in deionized water at a molar ratio of 1:1 to prepare a solution containing an active metal source at a concentration of 30 mmol / L;

[0154] F. Add the alumina support A-4 to the solution of step E and adsorb at a rotation speed of 400 rpm and a temperature of 50° C. for 4 hours. After adsorption, filter the solid and dry it at 120° C. for 25 hours.

[0155] The total amount of palladium chloride calculated as palladium element and silver nitrate calculated as silver element is 1 wt % relative to the total weight of the alumina support;

[0156] G. The solid obtained in step F was reduced at 500° C. in a H 2 / N 2 atmosphere (hydrogen content of 25 vol %) for 4 h to obtain an alumina-based catalyst A4. The parameters are listed in Table 1.

[0157] Example 5

[0158] Preparation of alumina-based catalyst A5:

[0159] A. Under ultrasonic conditions, 20 g of spherical alumina was subjected to a first contact reaction with a sodium hydroxide solution having a pH of 10;

[0160] The first contact reaction was carried out in two stages, each lasting 5 minutes at a temperature of 25°C and with a treatment liquid volume of 80 mL. After each stage, the solid was washed until the washed liquid was neutral.

[0161] The volume ratio of the dense packing volume of spherical alumina to the volume of sodium hydroxide solution is 1:3;

[0162] B. drying the solid obtained in step A at 100° C. for 20 h to obtain the first product;

[0163] C. The first product was added to 40 mL of a solution containing 0.3 mol of ethylene glycol and 0.2 mol of polyethylene glycol (molecular weight, 1200) (the concentration of the structure-directing agent was 12.5 mol / L), and ultrasonicated at 30°C for 60 min to obtain a mixed system;

[0164] The molar ratio of the total moles of polyethylene glycol and ethylene glycol to the strip-shaped aluminum oxide calculated as aluminum atoms is 0.035:1;

[0165] D. transferring the mixed system obtained in step C to a temperature-resistant autoclave and aging it at 180° C. for 10 h;

[0166] After the aging treatment is completed, the mixture is filtered to obtain a solid, and the solid is washed until the washed liquid is neutral;

[0167] The solid was dried at 120°C for 12 h and then calcined at 600°C for 6 h to obtain alumina support A-5, the parameters of which are listed in Table 1;

[0168] E. dissolving cobalt nitrate and nickel nitrate in deionized water at a molar ratio of 2:1 to prepare a solution containing an active metal source at a concentration of 90 mmol / L;

[0169] F. Add the alumina support A-5 to the solution of step E and adsorb at a rotation speed of 300 rpm and a temperature of 80°C for 4 hours. After adsorption, filter the solid and dry it at 100°C for 24 hours;

[0170] The total amount of cobalt nitrate calculated as cobalt element and nickel nitrate calculated as nickel element is 5 wt% relative to the total weight of the alumina support;

[0171] G. The solid obtained in step F was reduced at 600° C. in a H 2 / N 2 atmosphere (hydrogen content was 20 vol %) for 4 h to obtain an alumina-based catalyst A5. The parameters are listed in Table 1.

[0172] Example 6

[0173] Preparation of alumina-based catalyst A6:

[0174] A. Under ultrasonic conditions, 10 g of strip-shaped alumina was subjected to a first contact reaction with a hydrochloric acid solution having a pH of 5;

[0175] The first contact reaction was carried out in three stages, each lasting 10 min at 50°C and with a treatment liquid volume of 40 mL. After each stage, the solid was washed until the washed liquid was neutral.

[0176] The volume ratio of the dense packing volume of the strip-shaped alumina to the volume of the hydrochloric acid solution is 1:5;

[0177] B. drying the solid obtained in step A at 100° C. for 24 h to obtain the first product;

[0178] C. The first product was added to 40 mL of a solution containing 0.2 mol of hexadecyltrimethylammonium bromide, 0.2 mol of sodium dodecylsulfonate, and 0.1 mol of polyethylene glycol (molecular weight, 1000) (the concentration of the structure-directing agent was 12.5 mol / L), and ultrasonicated at 35°C for 30 min to obtain a mixed system;

[0179] The molar ratio of the total moles of hexadecyltrimethylammonium bromide, sodium laurylsulfonate and polyethylene glycol to the strip-shaped aluminum oxide calculated as aluminum atoms is 0.004:1;

[0180] D. Transfer the mixed system obtained in step C to a temperature-resistant autoclave and age it at 160° C. for 8 h;

[0181] After the aging treatment is completed, the mixture is filtered to obtain a solid, and the solid is washed until the washed liquid is neutral;

[0182] The solid was dried at 120°C for 10 h and then calcined at 500°C for 4 h to obtain alumina support A-6, the parameters of which are listed in Table 1;

[0183] E. dissolving nickel nitrate and cobalt nitrate in deionized water at a molar ratio of 3:1 to prepare a solution containing an active metal source at a concentration of 100 mmol / L;

[0184] F. Add the alumina support A-6 to the solution of step E and adsorb at a rotation speed of 250 rpm and a temperature of 30° C. for 4 h. After adsorption, filter the solid and dry it at 120° C. for 24 h.

[0185] The total amount of nickel nitrate calculated as nickel element and cobalt nitrate calculated as cobalt element is 5 wt% relative to the total weight of the alumina support;

[0186] G. The solid obtained in step F was reduced at 650° C. in a H 2 / N 2 atmosphere (hydrogen content of 25 vol %) for 2 h to obtain an alumina-based catalyst A6. The parameters are listed in Table 1.

[0187] Comparative Example 1

[0188] Preparation of catalyst D1:

[0189] A. Under ultrasonic conditions, 10 g of spherical alumina was contacted with 20 mL of deionized water to obtain support D-1;

[0190] The first contact reaction was carried out in three stages, each lasting 30 min at a temperature of 25°C.

[0191] B. dissolving palladium chloride in deionized water to prepare a solution containing an active metal source at a concentration of 20 mmol / L;

[0192] C. Add the solution obtained in step B to the support obtained in step A, and adsorb at a rotation speed of 200 rpm and a temperature of 50°C for 2 hours. After adsorption, filter to obtain a solid and dry it at 120°C for 12 hours;

[0193] The amount of palladium chloride used, calculated as palladium element, is 0.5 wt % relative to the total weight of the alumina support;

[0194] D. The solid obtained in step F was reduced at 200° C. under H 2 atmosphere for 4 h to obtain catalyst D1.

[0195] Comparative Example 2

[0196] A. Under ultrasonic conditions, 10 g of spherical alumina was contacted with a hydrochloric acid solution with a pH of 3.5;

[0197] The contact reaction was carried out in three stages, each lasting 60 min at 25°C, with a treatment liquid volume of 20 mL. After each stage, the solid was washed until the washed liquid was neutral.

[0198] The volume ratio of the dense packing volume of spherical alumina to the hydrochloric acid solution is 1:2;

[0199] B. drying the solid obtained in step A at 120° C. for 12 h to obtain alumina support D-2;

[0200] C. dissolving palladium chloride in deionized water to prepare a solution containing an active metal source at a concentration of 20 mmol / L;

[0201] D. Add the alumina support D-2 to the solution of step C and adsorb for 2 h at a rotation speed of 200 rpm and a temperature of 50° C. After adsorption, filter the solid and dry it at 120° C. for 12 h.

[0202] The amount of palladium chloride used, calculated as palladium element, is 0.5 wt % relative to the total weight of the alumina support;

[0203] E. The solid obtained in step F was reduced at 200° C. in a H 2 atmosphere for 4 h to obtain an alumina-based catalyst D2. The parameters are listed in Table 1.

[0204] The alumina supports prepared in Examples 1 and 2 were subjected to XRD tests, and the results were as follows: Figure 1 As shown, according to Figure 1 It can be seen that the prepared samples are all γ-alumina, and there are no impurity peaks of other species, which proves that the construction of the external open pore structure has no obvious change on the crystal form of the material.

[0205] The pore size distribution curve of the alumina carrier prepared in Example 3 and Comparative Example 2 was tested. The results are as follows: Figure 2 As shown, according to Figure 2 It can be seen that the alumina carrier prepared by the method disclosed in the present invention has pores with a pore diameter of more than 10 nm, that is, it has an external open pore structure.

[0206] The alumina support prepared in Example 5 was subjected to SEM testing, and the results were as follows: Figure 3 As shown, according to Figure 3 It can be seen that the flower-shaped alumina array with external open pores grows uniformly on the surface of the alumina material.

[0207] Figure 4 This is a cross-sectional view of the catalyst A1 prepared in Example 5, tested by a high-power optical microscope. Figure 4It can be seen that the darker part in the carrier shell is the impregnation layer of the active metal, and the lighter part inside is the alumina layer where the active metal has not been impregnated. Therefore, it can be seen from the figure that the active metal is mainly distributed on the outer surface of the carrier, showing an eggshell-shaped distribution in the radial direction.

[0208] Test Case

[0209] The catalysts prepared in the examples and comparative examples were used in the reaction of preparing hydrogen peroxide by hydrogenation of anthraquinone:

[0210] The reaction process is as follows: 10g of catalyst is loaded into a reactor, along with 50mL of working solution. Nitrogen is introduced at a rate of 200mL / min for 5 minutes to displace the air in the reactor. The temperature is then raised to 50°C at a rate of 5°C / min. Once the temperature stabilizes, hydrogen is introduced at a rate of 200mL / min to initiate the reaction. After 30 minutes of reaction, the working solution is released, resulting in a pressure of 0.5MPa and a molar ratio of hydrogen to anthraquinone of 13.9:1.

[0211] The working solution used was a 1:1 (volume ratio) mixture of 1,3,5-trimethylbenzene and trioctyl phosphate. The anthraquinone molecular concentration in the working solution was 80 g / L.

[0212] After oxidation and extraction of the working solution, the hydrogen peroxide yield was determined using potassium permanganate titration: hydrogen peroxide yield = 5CVoM / 2V. Where C is the concentration of the potassium permanganate solution, Vo is the amount of potassium permanganate solution consumed, V is the volume of hydrogen peroxide solution used for titration, and M is the molar mass of hydrogen peroxide.

[0213] Table 1

[0214]

[0215] According to the above data, the alumina carrier prepared by the method disclosed in the present invention has an external open pore structure and a relatively large specific surface area. The catalyst prepared using it has an eggshell-type structure, high active metal dispersion and good mass and heat transfer performance. It can be used for the hydrogenation reaction of anthraquinone to obtain a higher yield.

[0216] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0217] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0218] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for preparing an alumina support, characterized in that: The method comprises the following steps: S1, performing a first contact reaction between the formed alumina and the treatment liquid to obtain a first product; S2, subjecting the first product to a second contact reaction with a solution containing a structure-inducing agent; S3, subjecting the mixture obtained from the second contact reaction to an aging treatment; The treatment liquid is an acidic solution or an alkaline solution; The structure directing agent includes one or more of sulfonates with 10-18 carbon atoms, alkyltrimethylammonium salts with 10-20 carbon atoms, ethylene glycol or polyethylene glycol.

2. The method according to claim 1, wherein In step S1, the first contact reaction is carried out in stages under ultrasonic conditions. After each stage of reaction, the solid is washed until the washed liquid is neutral before the next stage of reaction is carried out. The reaction time of each stage is 10s-120min, the reaction temperature of each stage is 25-100°C, and the number of stages is any integer from 1 to 50; Optionally, step S1 further comprises: performing a first drying treatment on the solid obtained by the first contact reaction; The conditions of the first drying treatment include: a temperature of 50-200° C. and a time of 8-36 hours.

3. The method according to claim 2, wherein: The acidic solution includes hydrochloric acid solution and / or nitric acid solution, and the pH value of the acidic solution is 3-5; The alkaline solution includes sodium hydroxide solution and / or potassium hydroxide solution, and the pH value of the alkaline solution is 9-12; The volume ratio of the dense packing volume of the shaped alumina to the treatment liquid used in each stage of the first contact reaction is 1:(1.2-10).

4. The method according to claim 1, wherein In step S2, the structure inducing agent includes one or more of sodium hexadecyl sulfonate, sodium dodecyl sulfonate, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, ethylene glycol and polyethylene glycol; The molar ratio of the structural inducing agent to the shaped alumina calculated as aluminum element is (0.004-0.05):1; The second contact reaction is carried out under ultrasonic conditions for 10-120 minutes at a temperature of 25-80°C.

5. The method according to claim 1, wherein In step S3, the aging treatment conditions include: a time of 4-48 hours and a temperature of 80-180°C; The method further comprises: sequentially subjecting the solid obtained from the aging treatment to a washing treatment, a second drying treatment, and a heat treatment; The conditions of the second drying treatment include: a time of 8-72 hours and a temperature of 100-180°C; The heat treatment method includes roasting, and the conditions include: time is 4-10 hours, and temperature is 400-1200°C.

6. An alumina carrier prepared by the method according to any one of claims 1 to 5.

7. The alumina carrier according to claim 6, wherein The specific surface area of ​​the alumina carrier is 100-350m 2 / g, pore volume of 0.40-1.20cm 3 / g, and pores with a pore diameter of 8-20 nm account for more than 80% of the total pore volume.

8. A method for preparing an alumina-based catalyst, characterized in that: The method comprises: subjecting the alumina support according to claim 6 or 7 to a third contact reaction with a solution containing an active metal source; The active metal source includes one or more of a palladium source, a platinum source, a gold source, an iridium source, a ruthenium source, a silver source, a copper source and a cobalt source.

9. The method according to claim 8, wherein The active metal source includes one or more of nitrates, chlorine-containing compounds and acetylacetonate; In the solution containing the active metal source, the concentration of the active metal source is 1-100 mmol / L; The amount of the active metal source calculated as metal element is 0.1-10 wt % relative to the total weight of the alumina support.

10. The method according to claim 8, wherein The third contact reaction is carried out under stirring conditions, with a rotation speed of 100-500 rpm, a time of 0.5-6 hours, and a temperature of 25-80°C.

11. The method according to claim 8, wherein The method further includes: performing a third drying treatment on the solid obtained by the third contact reaction, wherein the conditions of the third drying treatment include: a temperature of 100-180° C. and a time of 8-72 hours; Optionally, the method further comprises: performing a reduction treatment on the pre-product obtained by the third drying treatment; The reduction treatment is carried out in a hydrogen atmosphere at a temperature of 80-500° C. for 0.5-8 h. The hydrogen-containing atmosphere includes a hydrogen atmosphere or a hydrogen-nitrogen atmosphere, and the hydrogen content in the hydrogen-nitrogen atmosphere is 10-50% by volume.

12. An alumina-based catalyst prepared by the method according to any one of claims 8 to 11.

13. The alumina-based catalyst according to claim 12, wherein The alumina-based catalyst comprises an alumina carrier and a metal active component, and the dispersion degree of the metal active component is 70-99%.

14. A hydrogenation reaction comprising contacting a material to be hydrogenated, hydrogen and a catalyst, characterized in that: The catalyst comprises the alumina-based catalyst according to claim 12 or 13.

15. The hydrogenation reaction according to claim 14, wherein The material to be hydrogenated includes one of anthraquinone and an olefin having 2 to 6 carbon atoms.

16. The hydrogenation reaction according to claim 15, wherein The material to be hydrogenated is anthraquinone, the temperature of the hydrogenation reaction is 40-80°C, the pressure is 0.1-1.2 MPa, the molar ratio of the hydrogen to the material to be hydrogenated is (4-200):1, and the weight ratio of the metal active component in the catalyst calculated as metal element to the raw material to be hydrogenated is 1:(8-1200).

17. The hydrogenation reaction according to claim 15, wherein The material to be hydrogenated is olefin, the temperature of the hydrogenation reaction is 100-300°C, the pressure is 0.1-1.2 MPa, the molar ratio of hydrogen to the material to be hydrogenated is (2-100):1, and the reaction space velocity is 5000-12000h -1 .

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