Supported catalyst prepared by deposition-precipitation method, preparation method thereof and method for preparing octenol

Abstract

The present invention relates to the field of supported catalysts, and discloses a supported catalyst prepared by a deposition-precipitation method, a preparation method thereof, and a method for preparing octenol, the supported catalyst comprises a carrier and an active component supported on the carrier, the supported catalyst is characterized in that the carrier is Al2O3, the active component is copper, and the catalyst is a metal oxide. Based on the total weight of the supported catalyst, the content of the copper is 15-40wt%. The supported catalyst has small-size active sites uniformly distributed on the surface of the carrier, relatively high specific surface area and metal dispersity, and can remarkably improve the conversion rate of octenal and the yield of octenol.

Description

Technical Field

[0001] This invention relates to the field of supported catalyst technology, specifically to a supported catalyst prepared by deposition precipitation method, a preparation method thereof, and a method for preparing octenol. Background Technology

[0002] 2-Ethyl-2-hexenol (abbreviated as octenol) is an important biopherin and organic intermediate with broad application markets in medicine, pesticides, and daily chemicals. The process route for preparing octenol by hydrogenation of 2-ethyl-2-hexenal (abbreviated as octenal) has advantages such as high atom utilization, low environmental risk, and simple post-processing, and has become the mainstream design concept for the green industrial production of octenol. However, the activation energy required for hydrogenation of the C=O bond of octenal (approximately 40 kJ·mol⁻¹) is significant. -1 ) higher than C=C bond (approximately 35 kJ·mol) -1 The former is thermodynamically more disadvantageous. Therefore, achieving selective hydrogenation of the C=O bond in octenal is a key process step in the preparation of octenol.

[0003] Current industrial production often employs homogeneous catalytic systems to achieve selective hydrogenation of the C=O bond in octenal.

[0004] CN103288597B discloses a rhodium-bisphosphine ligand catalyst for catalyzing the selective reduction of octenal by NaBH4, with an octenal yield of up to 85%.

[0005] In addition, CN103857468B discloses a series of ruthenium / bidentate ligand complex catalysts, which can utilize H2 as a hydrogen source to achieve the catalytic oxidation of C4-C4 ligands. 19 Selective hydrogenation of unsaturated aldehydes and ketones is a crucial area of ​​research. However, homogeneous catalytic systems face challenges such as high catalyst production costs, short cycle life, and difficulties in separation. In recent years, the development of highly selective supported catalysts has become a key focus in this field.

[0006] CN109311789B discloses a method for preparing various α,β-unsaturated alcohols using an activated carbon-supported ruthenium-iron catalyst and a tertiary amine promoter. This catalyst achieves high substrate conversion and selectivity for unsaturated alcohols, but its precious metal raw material is costly, its active metal sites are easily lost, and its preparation process generates a large amount of wastewater. Furthermore, the tertiary amine promoter further increases separation costs and environmental risks.

[0007] CN114433103B discloses a method for selectively preparing octanal or octenol from octenal. In this method, the catalyst uses non-noble metals such as Cu, Ni, and Co as the active component, and further enhances its catalytic performance using alkaline earth metals such as Mg and Ba, and rare earth metals such as La and Ce. Although the catalyst exhibits high economic efficiency and catalytic activity, the selectivity for octenol is low, making it difficult to meet the demands of industrial production.

[0008] Therefore, developing novel selective hydrogenation catalysts that are rich in raw material resources, have simple preparation processes, and are both economical and environmentally friendly, and optimizing the process route for the preparation of octenol from octenal, remains one of the key issues that urgently need to be addressed in this field. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of existing octenol preparation processes that are difficult to balance between economy and catalytic performance. This invention provides a supported catalyst prepared by deposition precipitation method, its preparation method, and a method for preparing octenol. The supported catalyst has small active sites uniformly distributed on the surface of the support, high specific surface area, and high metal dispersion, which can significantly improve the conversion rate of octenal and the yield of octenol.

[0010] To achieve the above objectives, the first aspect of the present invention provides a supported catalyst comprising a support and an active component supported on the support, wherein the support is Al2O3, the active component is copper, and the copper content is 15-40 wt% based on the total weight of the supported catalyst.

[0011] A second aspect of the present invention provides a method for preparing a supported catalyst, wherein the preparation method includes:

[0012] (1) Al2O3 was immersed in a copper salt solution for deposition;

[0013] (2) The material obtained by deposition in step (1) is dried and then contacted and mixed with an alkaline solution to carry out a precipitation reaction;

[0014] (3) The product after step (2) is filtered, washed, dried and calcined to obtain a supported copper-based catalyst.

[0015] A third aspect of the present invention provides a supported catalyst prepared by the preparation method described above.

[0016] A fourth aspect of the present invention provides a method for preparing octenol from octenal hydrogenation, the method comprising: reacting a catalyst, octenal, and an inert solvent in the presence of hydrogen to obtain a product containing octenol, wherein the catalyst is the aforementioned supported catalyst.

[0017] Through the above technical solution, the present invention has the following beneficial effects:

[0018] The Al2O3-supported copper-based catalyst prepared by the deposition-precipitation method of this invention has active sites uniformly distributed on the surface of the Al2O3 support, exhibiting high specific surface area and metal dispersion, which can significantly improve the conversion rate of octenal and the yield of octenol. Furthermore, the preparation process is simple, and the raw materials for preparing this supported catalyst are abundant, thereby reducing the catalyst preparation cost. Attached Figure Description

[0019] Figure 1 The XRD characterization pattern of the copper-based catalyst prepared in Example 1 is shown below.

[0020] Figure 2 These are optical photographs of the copper-based catalyst prepared in Example 1 and its cross-section.

[0021] Figure 3 This is a schematic diagram of the N2 adsorption-desorption curves of the copper-based catalyst prepared in Example 1;

[0022] Figure 4 This is the most probable pore size distribution diagram of the copper-based catalyst prepared in Example 1;

[0023] Figure 5 The image shows the XRD characterization pattern of the copper-based catalyst prepared in Comparative Example 2. Detailed Implementation

[0024] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0025] As previously stated, the first aspect of the present invention provides a supported catalyst comprising a support and an active component supported on the support, wherein the support is Al2O3, the active component is copper, and the copper content is 15-40 wt% based on the total weight of the supported catalyst.

[0026] According to the present invention, preferably, the copper content is 15-30 wt%, more preferably 16-30 wt%, and more preferably 16.5-29.4 wt%, based on the total weight of the supported catalyst.

[0027] The inventors of this invention have discovered that the present invention employs a deposition-precipitation method, in which Al2O3 is first immersed in a copper-containing salt solution for deposition, and then the resulting material is transferred to an alkaline solution for precipitation reaction. Due to the precipitation process, active metal ions migrate to the surface of the support, and the metal nanoparticles are smaller in size after deposition. Therefore, this supported catalyst has small active sites uniformly distributed on the surface of the support, a high specific surface area, and metal dispersion, which can significantly improve the conversion rate of octenal and the yield of octenol.

[0028] According to the present invention, preferably, the Al2O3 is a pentadentate spherical Al2O3; more preferably, the crystal phase of the Al2O3 is a single phase or a mixture of γ-Al2O3, δ-Al2O3, and θ-Al2O3. It should be noted that the tooth shape can be rectangular or angled, and the angle is not particularly limited; for example, the angle can be between 30° and 45°. Furthermore, it should be noted that the crystal phases γ-Al2O3, δ-Al2O3, and θ-Al2O3 have a uniform pore structure, a large specific surface area, and surface acidic sites, while α-Al2O3 has a wide pore size distribution, a small specific surface area, and low surface acidity. Therefore, in the present invention, using Al2O3 with a single phase or a mixture of γ-Al2O3, δ-Al2O3, and θ-Al2O3 can effectively improve the metal loading and its dispersion, and provide selective adsorption sites for the octenal C=O group, thereby improving catalytic activity and selectivity.

[0029] According to the present invention, the supported catalyst may be spherical.

[0030] According to the present invention, the specific surface area of ​​the supported catalyst can be 70-170 m² / g, and the most probable pore size is 5-15 nm; preferably, the specific surface area of ​​the supported catalyst is 100-160 m² / g, and the most probable pore size is 8-12 nm.

[0031] According to the present invention, the grain size of the active component (metal) is 10-30 nanometers, preferably 15-25 nanometers.

[0032] According to the present invention, the copper metal dispersion in the supported catalyst is 6-15%, preferably 10-12%.

[0033] A second aspect of the present invention provides a method for preparing a supported catalyst, wherein the preparation method includes:

[0034] (1) Al2O3 was immersed in a copper salt solution for deposition;

[0035] (2) The material obtained by deposition in step (1) is dried and then contacted and mixed with an alkaline solution to carry out a precipitation reaction;

[0036] (3) The product after step (2) is filtered, washed, dried and calcined to obtain a supported copper-based catalyst.

[0037] According to the present invention, the copper salt in the copper-containing salt solution is selected from at least one of copper nitrate, copper sulfate, and copper acetate; the copper-containing salt solution can be a nitric acid solution of copper salt.

[0038] According to the present invention, the amount of copper salt used is 5-30 parts by weight, preferably 8-25 parts by weight, relative to 25 parts by weight of Al2O3.

[0039] According to the present invention, the concentration of the copper-containing salt solution is 20-75 wt%, preferably 50-75 wt%.

[0040] According to the present invention, the alkaline solution comprises at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate; the alkaline solution comprises at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate; in the present invention, the concentration of the alkaline solution is not specifically limited, and can be 1 mmol / L-4 mol / L, preferably 0.01-2 mol / L, as long as the pH value is 11-14, preferably 12-13.

[0041] According to the present invention, in step (1), Al2O3 is immersed in a copper-containing salt solution for deposition, wherein the immersion conditions may include immersion at a temperature of 40-50°C for 20-60 min. Furthermore, there are no particular limitations on the drying conditions for the material obtained after deposition; for example, it may be dried at a temperature of 60-100°C for 0.5-1.5 h.

[0042] According to the present invention, in step (2), the conditions for the precipitation reaction include: a reaction temperature of 20-60°C and a time of 15-60 min; preferably, the reaction temperature is 30-45°C and the time is 15-30 min. In the present invention, limiting the precipitation reaction conditions to the aforementioned range has the advantage of being suitable for actual industrial production. If the temperature is too low, an additional heating process is required, and the metal on the carrier surface will precipitate into the solution. If the temperature is too high, the precipitate particles will be large and decompose to form black copper oxide particles.

[0043] According to the present invention, the conditions for the precipitation reaction include: pH 8-14, preferably 9-12. In the present invention, limiting the pH condition to the aforementioned range allows copper ions to precipitate more completely on the carrier surface. If the pH is too low, copper ions will not be able to precipitate. If the pH is too high, it will cause local violent reactions and significant temperature rise, destroying the macroscopic structure of the Al2O3 carrier and resulting in large-sized precipitate particles.

[0044] According to the present invention, in step (3), the product after the reaction in step (2) is subjected to filtration, washing, drying, calcination and reduction treatment to obtain a supported catalyst; wherein, filtration can be carried out by methods well known in the art; washing can be done with deionized water, and the number of washings is not particularly limited, preferably 3-5 times; drying can be done at a temperature of 60-100℃ for 4-24h; in the present invention, the calcination conditions include: a temperature of 200-300℃ and a time of 4-8h; preferably, a temperature of 240-260℃ and a time of 5-6h.

[0045] According to the present invention, in order to obtain a higher copper loading, the preparation method further includes: in step (3), the product after the reaction in step (2) is filtered, washed, dried, and calcined (before the reduction step), and then steps (1) to (3) are repeated to obtain a supported copper-based catalyst. It should also be noted that steps (1) to (3) can be repeated multiple times before the reduction step, preferably 2-3 times; in the present invention, it should be noted that the repeated process refers to the absence of a reduction step, ultimately resulting in a supported copper-based catalyst.

[0046] According to a particularly preferred embodiment of the present invention, a method for preparing a supported catalyst includes:

[0047] (1) Immerse the five-toothed spherical Al2O3 in a nitric acid solution containing copper salt and then dry it;

[0048] (2) Transfer the material obtained in step (1) to an alkaline solution, stir and mix to carry out the reaction;

[0049] (3) After the reaction is complete, the mixture is filtered, washed, dried and calcined.

[0050] (4) Repeat steps (1) to (3) 2-3 times to obtain the alumina-supported copper-based catalyst.

[0051] A third aspect of the present invention provides a supported catalyst prepared by the preparation method described above.

[0052] A fourth aspect of the present invention provides a method for preparing octenol from octenal hydrogenation, the method comprising: reacting a catalyst, octenal, and an inert solvent in the presence of hydrogen to obtain a product containing octenol, wherein the catalyst is the aforementioned supported catalyst.

[0053] In this invention, a method for preparing 2-ethyl-2-hexenol (hereinafter referred to as octenol) from 2-ethyl-2-hexenal (hereinafter referred to as octenal) is provided.

[0054] According to the present invention, the inert solvent may be a C1-C8 saturated alcohol, preferably ethanol and / or octanol.

[0055] According to the present invention, the weight ratio of the catalyst to octenal is 1:(1-15), preferably 1:(2-10).

[0056] According to the present invention, the weight ratio of the octenal to the inert solvent is 1:(1-10).

[0057] According to the present invention, the reaction conditions include: a temperature of 70-150°C and a reaction pressure of 1-7 MPa; preferably, the temperature is 90-120°C and the reaction pressure is 3-5 MPa.

[0058] The present invention will be described in detail below through embodiments.

[0059] In the following examples and comparative examples:

[0060] Octenal conversion rate = (moles of octenal in the raw material - moles of unreacted octenal) ÷ ​​moles of octenal in the raw material × 100%.

[0061] Octal selectivity = (moles of octal in the product) ÷ (moles of octenal in the feedstock - moles of unreacted octenal) × 100%.

[0062] Specific surface area, pore volume, and pore size distribution were measured by N2 adsorption-desorption method.

[0063] The content of copper component was determined by X-ray fluorescence spectrometry.

[0064] The chemical composition of the copper component was determined by X-ray diffraction, and the grain size of the active component (metal) was calculated using the Scherrer formula.

[0065] The copper component metal dispersion was measured by an AutoChem II 2920 dynamic chemisorption analyzer. The copper metal dispersion = number of active copper atoms on the catalyst surface ÷ total number of copper atoms in the catalyst.

[0066] Octenol is a commercially available product from Aladdin Company, brand name E156033.

[0067] All reagents used were commercially available and of analytical grade.

[0068] Example 1

[0069] This embodiment illustrates the supported catalyst prepared using the deposition-precipitation method of the present invention.

[0070] (1) 25g of pentadentate spherical γ-Al2O3 support was immersed in 75wt% copper nitrate aqueous solution (of which, the amount of copper nitrate calculated as metallic copper element was 8.3g), and after immersion at 50℃ for 20min, it was taken out, drained, and dried at 60℃ for 1h.

[0071] (2) Subsequently, the material obtained in step (1) was transferred to an aqueous sodium hydroxide solution with pH=13 and reacted at 30°C with stirring for 15 min;

[0072] (3) After filtering the product obtained in step (2), wash it three times with deionized water, dry it at 80°C for 5 hours, and calcine it at 250°C for 5 hours to obtain a supported catalyst, labeled as S1.

[0073] X-ray fluorescence spectroscopy (XRF) analysis showed that the copper loading in this supported catalyst was 19.8%.

[0074] X-ray diffraction (XRD) characterization, based on the Scherrer formula, estimated the copper grain size in this supported catalyst to be 16.7 nm and 23.1 nm. (See [reference needed]). Figure 1 . Figure 1 This is the XRD characterization result of the copper-based catalyst prepared in Example 1; from Figure 1 It can be seen that copper exists in the form of copper oxide in the copper-based catalyst prepared in Example 1. Based on the peaks at 35.47° and 38.77°, the crystallite size of copper is estimated to be 23.1 nm and 16.7 nm, respectively.

[0075] Dynamic chemisorption analysis revealed that the copper metal dispersion in this supported catalyst was 10.8%.

[0076] Furthermore, this supported catalyst is spherical, with the metal uniformly distributed on the surface of the support, and the metal content on the surface is much higher than that inside the support. Figure 2 . Figure 2 These are optical photographs of the copper-based catalyst prepared in Example 1 and its cross-section; from Figure 2 It can be seen that the metal is uniformly distributed on the surface of the carrier. Based on the color intensity in the cross-section, it can be concluded that the metal content on the surface of the carrier is much higher than that inside the carrier.

[0077] The supported catalyst has a specific surface area of ​​155 m² / g and a most probable pore size of 12 nm. (See [link to relevant documentation]). Figure 3-4 .

[0078] Figure 3 This is a schematic diagram of the N2 adsorption-desorption curves of the copper-based catalyst prepared in Example 1; from Figure 3 It can be seen that the copper-based catalyst prepared in Example 1 has mesoporous channels.

[0079] Figure 4 This is the most probable pore size distribution diagram of the copper-based catalyst prepared in Example 1; from Figure 4 It can be seen that the pore size of the copper-based catalyst prepared in Example 1 is between 8-25 nm, and the most probable pore size is 12 nm.

[0080] Example 2

[0081] This embodiment illustrates the supported catalyst prepared using the deposition-precipitation method of the present invention.

[0082] (1) 25g of pentadentate spherical δ-Al2O3 and θ-Al2O3 mixed-phase support were immersed in 75wt% copper nitrate aqueous solution (of which, the amount of copper nitrate calculated as metallic copper element was 8.3g), and after immersion at 50℃ for 20min, they were taken out, drained, and dried at 60℃ for 1h.

[0083] (2) Subsequently, the material obtained in step (1) was transferred to an aqueous sodium hydroxide solution with pH=12 and reacted at 30°C with stirring for 30 min;

[0084] (3) After filtering the product obtained in step (2), wash it three times with deionized water, dry it at 80°C for 5 hours, and calcine it at 250°C for 5 hours to obtain a supported catalyst, labeled as S2.

[0085] XRF characterization showed that the copper loading in this supported catalyst was 21.4%.

[0086] XRD characterization and Scherrer's formula suggest that the size of the copper grains in this supported catalyst is 20.9 nm and 24.6 nm.

[0087] Dynamic chemisorption analysis revealed that the copper metal dispersion in this supported catalyst was 10.3%.

[0088] In addition, the supported catalyst is spherical with a specific surface area of ​​141 m² / g and a most probable pore size of 11 nm.

[0089] Example 3

[0090] This embodiment illustrates the supported catalyst prepared using the deposition-precipitation method of the present invention.

[0091] (1) 25g of pentadentate spherical γ-Al2O3 support was immersed in 75wt% copper nitrate aqueous solution (of which, the amount of copper nitrate calculated as metallic copper element was 8.3g), and after immersion at 50℃ for 20min, it was taken out, drained, and dried at 60℃ for 1h.

[0092] (2) Subsequently, the material obtained in step (1) was transferred to a sodium bicarbonate aqueous solution with pH=12 and reacted at 30°C with stirring for 30 min.

[0093] (3) After filtering the product obtained in step (2), wash it three times with deionized water, dry it at 80°C for 5 hours, and calcine it at 250°C for 5 hours to obtain a supported catalyst, labeled as S3.

[0094] XRF characterization showed that the copper loading in this supported catalyst was 16.5%.

[0095] XRD characterization and Scherrer's formula suggest that the size of the copper grains in this supported catalyst is 15.6 nm and 21.5 nm.

[0096] Dynamic chemisorption analysis revealed that the copper metal dispersion in this supported catalyst was 11.6%.

[0097] In addition, the supported catalyst is spherical with a specific surface area of ​​164 m² / g and a most probable pore size of 11 nm.

[0098] Example 4

[0099] This embodiment illustrates the supported catalyst prepared using the deposition-precipitation method of the present invention.

[0100] (1) 25g of pentadentate spherical γ-Al2O3 support was immersed in 75wt% copper nitrate aqueous solution (of which, the amount of copper nitrate calculated as metallic copper element was 8.3g), and after immersion at 50℃ for 20min, it was taken out, drained, and dried at 100℃ for 1h.

[0101] (2) Subsequently, the material obtained in step (1) was transferred to an aqueous sodium carbonate solution with pH=12 and reacted at 30°C with stirring for 1 h.

[0102] (3) After filtering the product obtained in step (2), wash it three times with deionized water, dry it at 80°C for 5 hours, and calcine it at 250°C for 5 hours to obtain a supported catalyst, labeled as S4.

[0103] XRF characterization showed that the copper loading in this supported catalyst was 20.7%.

[0104] XRD characterization and Scherrer's formula suggest that the size of the copper grains in this supported catalyst is 18.0 nm and 22.1 nm.

[0105] Dynamic chemisorption analysis showed that the copper metal dispersion in this supported catalyst was 10.0%.

[0106] In addition, the supported catalyst is spherical with a specific surface area of ​​143 m² / g and a most probable pore size of 12 nm.

[0107] Example 5

[0108] This embodiment illustrates the supported catalyst prepared using the deposition-precipitation method of the present invention.

[0109] (1) 25g of pentadentate spherical γ-Al2O3 support was immersed in 75wt% copper nitrate aqueous solution (of which, the amount of copper nitrate calculated as metallic copper element was 8.3g), and after immersion at 50℃ for 20min, it was taken out, drained, and dried at 100℃ for 1h.

[0110] (2) Subsequently, the material obtained in step (1) was transferred to an aqueous sodium hydroxide solution with pH=13 and reacted at 30°C with stirring for 1 h.

[0111] (3) After filtering the product obtained in step (2), wash it three times with deionized water, dry it at 80°C for 5 hours, and calcine it at 250°C for 5 hours.

[0112] (4) Repeat steps (1)-(3) once with the product obtained in step (3) to obtain a supported catalyst, labeled as S5.

[0113] XRF characterization showed that the copper loading in this supported catalyst was 29.4%.

[0114] XRD characterization and Scherrer's formula revealed that the size of the copper crystals in the supported catalyst was 25.4 nm and 29.7 nm.

[0115] Dynamic chemisorption analysis revealed that the copper metal dispersion in this supported catalyst was 8.2%.

[0116] In addition, the supported catalyst is spherical with a specific surface area of ​​114 m² / g and a most probable pore size of 10 nm.

[0117] Example 6

[0118] This embodiment illustrates the supported catalyst prepared using the deposition-precipitation method of the present invention.

[0119] (1) 25g of pentadentate spherical γ-Al2O3 support was immersed in 75wt% copper nitrate aqueous solution (of which, the amount of copper nitrate calculated as metallic copper element was 8.3g), and after immersion at 50℃ for 20min, it was taken out, drained, and dried at 100℃ for 1h.

[0120] (2) Subsequently, the material obtained in step (1) was transferred to an aqueous sodium hydroxide solution with pH=13 and reacted at 30°C with stirring for 1 h.

[0121] (3) After filtering the product obtained in step (2), wash it three times with deionized water, dry it at 80°C for 5 hours, and calcine it at 250°C for 5 hours.

[0122] (4) Repeat steps (1)-(3) twice with the product obtained in step (3) to obtain a supported catalyst, labeled as S6.

[0123] XRF characterization showed that the copper loading in this supported catalyst was 34.0%.

[0124] XRD characterization and Scherrer's formula revealed that the size of the copper grains in the supported catalyst was 27.3 nm and 32.0 nm.

[0125] Dynamic chemisorption analysis revealed that the copper metal dispersion in this supported catalyst was 6.8%.

[0126] In addition, the supported catalyst is spherical with a specific surface area of ​​101 m² / g and a most probable pore size of 8 nm.

[0127] Comparative Example 1

[0128] Catalyst D1 was synthesized according to the preparation method in Example 14 of CN114433103B. The specific steps are as follows:

[0129] 20g of cobalt nitrate, 4g of copper nitrate, 5g of magnesium nitrate, and 1g of lanthanum nitrate were dissolved in deionized water and stirred evenly with 15mL of graphene oxide. The mixture was then impregnated onto 20g of zirconium oxide (ZrO2). The impregnated product was placed in a 90℃ oven and dried for 10h. The dried catalyst was then placed in a muffle furnace and heated to 210℃ at a rate of 140℃ / h, held for 7h; subsequently, the temperature was increased to 370℃ at a rate of 70℃ / h and held for 5h. The final catalyst product was obtained and labeled D1.

[0130] Comparative Example 2

[0131] The supported catalyst was prepared using the same method as in Example 1, except that no precipitation reaction was performed, i.e., step (2) was not carried out; only an impregnation method was used. Specifically:

[0132] (1) 25g of pentadentate spherical γ-Al2O3 support was immersed in 75wt% copper nitrate aqueous solution (of which, the amount of copper nitrate calculated as metallic copper element was 8.3g), and after immersion at 50℃ for 20min, it was taken out, drained, and dried at 60℃ for 1h.

[0133] (2) After filtering the product obtained in step (1), wash it three times with deionized water, dry it at 80°C for 5 hours, and calcine it at 250°C for 5 hours to obtain a supported catalyst, labeled as D2.

[0134] XRF characterization showed that the copper loading in this supported catalyst was 24.7%.

[0135] XRD characterization and, based on the Scherrer formula, the estimated sizes of copper grains in this supported catalyst are 21.7 nm and 27.0 nm. (See [reference needed]). Figure 5 . Figure 5 The image shows the XRD characterization results of the copper-based catalyst prepared in Comparative Example 2; from... Figure 5 It can be seen that in the copper-based catalyst prepared in Comparative Example 2, copper exists in the form of copper oxide. Based on the peaks at 35.46° and 38.64°, the copper grain size is estimated to be 21.7 nm and 27.0 nm, respectively.

[0136] Dynamic chemisorption analysis revealed that the copper metal dispersion in this supported catalyst was 3.5%.

[0137] In addition, the supported catalyst is spherical with a specific surface area of ​​101 m² / g and a most probable pore size of 14 nm.

[0138] Comparative Example 3

[0139] The supported catalyst was prepared using the same method as in Example 5, except that no precipitation reaction was performed, i.e., step (2) was not carried out; only an impregnation method was used. Specifically:

[0140] (1) 25g of pentadentate spherical γ-Al2O3 support was immersed in 75wt% copper nitrate aqueous solution (of which, the amount of copper nitrate calculated as metallic copper element was 8.3g), and after immersion at 50℃ for 20min, it was taken out, drained, and dried at 60℃ for 1h.

[0141] (2) After filtering the product obtained in step (1), wash it three times with deionized water, dry it at 80°C for 5 hours, and calcine it at 250°C for 5 hours.

[0142] (3) Repeat steps (1)-(2) once with the product obtained in step (2) to obtain a supported catalyst, labeled as D3.

[0143] XRF characterization showed that the copper loading in this supported catalyst was 36.3%.

[0144] XRD characterization and, based on the Scherrer formula, the estimated sizes of copper grains in this supported catalyst are 30.1 nm and 37.6 nm. (See [reference needed]). Figure 5 .

[0145] Dynamic chemisorption analysis revealed that the copper metal dispersion in this supported catalyst was 2.2%.

[0146] In addition, the supported catalyst is spherical with a specific surface area of ​​80 m² / g and a most probable pore size of 10 nm.

[0147] Comparative Example 4

[0148] The supported catalyst was prepared using the same method as in Example 1, except that the “γ-Al2O3 support” in Example 1 was replaced with the “α-Al2O3 support”; wherein the macroscopic shape and size of the α-Al2O3 support were the same as those of the γ-Al2O3 support.

[0149] The supported catalyst was obtained and labeled D4.

[0150] XRF characterization showed that the copper loading in this supported catalyst was 11.2%.

[0151] XRD characterization revealed that the size of the copper grains in the supported catalyst was 40.3 nm, calculated using the Scherrer formula.

[0152] Dynamic chemisorption analysis revealed that the copper metal dispersion in this supported catalyst was 0.9%.

[0153] In addition, the supported catalyst is spherical with a specific surface area of ​​26 m² / g and a most probable pore size of 22 nm.

[0154] Comparative Example 5

[0155] The supported catalyst was prepared using the same method as in Example 1, except that “copper nitrate” in Example 1 was replaced with “nickel nitrate”.

[0156] The supported catalyst was obtained and labeled D5.

[0157] XRF characterization showed that the active component nickel loading in this supported catalyst was 19.4%.

[0158] In addition, the supported catalyst is spherical with a specific surface area of ​​143 m² / g and a most probable pore size of 12 nm.

[0159] Test case

[0160] Evaluation of the hydrogenation reaction of octenal to octenol

[0161] The supported copper-based catalysts prepared in Examples 1-6 and Comparative Examples 1-5 were reduced at 250°C under a hydrogen atmosphere for 4 hours. Then, 2g of the reduced catalyst, 4g of octenal, and 16g of inert solvent were added to a stainless steel reactor, which was completely sealed, and the air inside the reactor was replaced three times with high-purity H2. The reaction was carried out for 5 hours at the appropriate reaction temperature and H2 pressure, with a stirring rate of 200 rpm, to obtain a product containing octenol. The experimental results are shown in Table 1.

[0162] Table 1

[0163]

[0164]

[0165] As shown in Table 1, the Al₂O₃-supported copper-based catalyst prepared by the deposition-precipitation method of this invention can significantly improve the yield of octenol with a lower metal loading under the same reaction conditions. Structurally, the catalyst prepared by the deposition-precipitation method exhibits uniformly distributed metal active sites on the surface of the Al₂O₃ support, possessing a large specific surface area and high active metal dispersion. This catalyst helps reduce raw material input and energy consumption in industrial production and has high application potential.

[0166] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A supported catalyst, said supported catalyst comprising a support and an active component supported on said support, characterized in that, The support is Al2O3, the active component is copper, and the copper content is 15-40 wt% based on the total weight of the supported catalyst.

2. The supported catalyst according to claim 1, wherein, Based on the total weight of the supported catalyst, the copper content is 15-30 wt%, preferably 16-30 wt%. And / or, the Al2O3 is a pentadentate spherical Al2O3; preferably, the crystal phase of the Al2O3 is a single phase or a mixture of γ-Al2O3, δ-Al2O3 and θ-Al2O3; And / or, the supported catalyst is spherical, preferably, the particle size of the supported catalyst is between 2-5 mm; And / or, the supported catalyst has a specific surface area of ​​70-170 m² / g and a most probable pore size of 5-15 nm; And / or, the grain size of the active component is 10-30 nanometers, preferably 15-25 nanometers; And / or, the copper metal dispersion in the supported catalyst is 6-15%, preferably 10-12%.

3. A method for preparing a supported catalyst, characterized in that, The preparation method includes: (1) Al2O3 was immersed in a copper salt solution for deposition; (2) The material obtained by deposition in step (1) is dried and then contacted and mixed with an alkaline solution to carry out a precipitation reaction; (3) The product after step (2) is filtered, washed, dried and calcined to obtain a supported copper-based catalyst.

4. The preparation method according to claim 3, wherein, The copper salt in the copper-containing salt solution is selected from at least one of copper nitrate, copper sulfate, and copper acetate; Preferably, the amount of copper salt used is 5-30 parts by weight relative to 25 parts by weight of Al2O3, more preferably 8-25 parts by weight; Preferably, the concentration of the copper salt solution is 20-75 wt%, more preferably 50-75 wt%.

5. The preparation method according to claim 3, wherein, In step (2), the conditions for the precipitation reaction include: a reaction temperature of 20-60℃ and a time of 15-60 min; preferably, the reaction temperature is 30-45℃ and the time is 15-30 min. Preferably, the conditions for the precipitation reaction include: pH 8-14, preferably 9-12; In step (3), the calcination conditions include: a temperature of 200-300℃ and a time of 4-8h; preferably, the calcination temperature is 240-260℃ and the time is 5-6h.

6. The preparation method according to any one of claims 3-5, wherein, The preparation method further includes: repeating steps (1) to (3) 2-3 times after step (3) to obtain a supported copper-based catalyst.

7. A supported catalyst prepared by the preparation method according to any one of claims 3-6.

8. A method for preparing octenol by hydrogenation of octenal, the method comprising: In the presence of hydrogen, a catalyst, octenal, and an inert solvent are brought into contact to react and a product containing octenol is obtained, characterized in that the catalyst is a supported catalyst as described in any one of claims 1, 2, and 7.

9. The method according to claim 8, wherein, The inert solvent is a C1-C8 saturated alcohol, preferably ethanol and / or octanol; And / or, the weight ratio of the catalyst to octenal is 1:(1-15), preferably 1:(2-10); Preferably, the weight ratio of the octenal to the inert solvent is 1:(1-10).

10. The method according to claim 8 or 9, wherein, The reaction conditions include: a temperature of 70-120℃ and a reaction pressure of 1-7MPa; Preferably, the reaction temperature is 90-120℃ and the reaction pressure is 3-5MPa.

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