A copper-based octenal hydrogenation catalyst, its preparation method and application

Abstract

The application provides a copper-based octene aldehyde hydrogenation catalyst and a preparation method and application thereof, and relates to the technical field of copper-based aldehyde hydrogenation catalysts. 2+ with Al 3+ co-precipitation and calcination, and the copper species is dispersed in the boehmite precursor framework and pore structure; the multi-level pore alumina carrier has a multi-level pore structure composed of mesopores, interlayer pores and intergranular pores. Through the regulation of the hydrolysis, condensation and boehmite sheet assembly process of aluminum species by the organic small molecule bifunctional ligand containing nitrogen and hydroxyl functional groups, the application realizes the synergistic regulation of the multi-level pore structure construction of the alumina carrier and the high dispersion of the copper active species, and has good industrial application prospects.

Description

Technical Field

[0001] This invention relates to the field of copper-based aldehyde hydrogenation catalyst technology, and in particular to a copper-based octenal hydrogenation catalyst, its preparation method, and its application. Background Technology

[0002] Selective hydrogenation of aldehydes is an important reaction in the preparation of alcohols. The hydrogenation of octenal to isooctanol is widely used in plasticizers, solvents, and fine chemical intermediates. Copper-based catalysts are commonly used in aldehyde hydrogenation reactions due to their low cost, good aldehyde hydrogenation activity, and high selectivity for alcohol products. For substrates such as octenal with long carbon chains and relatively large molecular sizes, the pore structure of the catalyst, the dispersion state of the copper species, and the interaction between the copper species and the support all directly affect reactant diffusion, active site utilization, and isooctanol selectivity.

[0003] Existing copper-based aldehyde hydrogenation catalysts typically use alumina as a support, which is mostly obtained by calcination conversion of boehmite precursors. Traditional boehmite is generally prepared by the hydrolysis and precipitation of aluminum salts. During its formation, the nanosheets are prone to disordered stacking, resulting in a relatively simple pore structure and narrow pore size distribution in the calcined alumina support, limiting pore connectivity and mass transfer capacity. In the hydrogenation of octenal, this pore structure easily restricts the diffusion of substrate molecules, hydrogen, and products within the catalyst pores, thereby reducing reaction efficiency and potentially increasing the formation of incomplete hydrogenation byproducts and heavy component byproducts.

[0004] Furthermore, the copper active component in existing copper-based catalysts is mostly introduced through post-loading methods such as impregnation and deposition. In these methods, copper species are mainly distributed on the outer surface of the support or near the pores. The binding strength between copper species and the support is limited, and they are prone to migration, aggregation, or sintering during subsequent drying, calcination, reduction, and reaction processes. This leads to an increase in copper particle size, a decrease in copper specific surface area, and a reduction in available active sites, thereby affecting the catalyst's activity, selectivity, and operational stability.

[0005] To improve the pore structure of alumina supports or enhance the dispersibility of copper species, existing technologies typically employ template agents, structure-directing agents, pore regulators, or auxiliary elements such as phosphorus, boron, zirconium, titanium, and lanthanum to modify the support or active component. While these methods can improve catalyst performance to some extent, they still suffer from drawbacks such as the difficulty in simultaneously achieving pore structure regulation and high copper species dispersion, numerous steps, complex composition systems, and high costs. Furthermore, the use of template agents or surfactants requires subsequent removal steps, potentially increasing energy consumption and environmental burden, which is detrimental to industrial-scale applications.

[0006] Therefore, there is an urgent need to develop a copper-based octenal hydrogenation catalyst and its preparation method that does not rely on template agents and additional auxiliary elements and can simultaneously regulate the hierarchical pore structure of the support and the dispersion state of copper species during the alumina precursor formation stage. Summary of the Invention

[0007] In view of this, the present invention provides a copper-based octenal hydrogenation catalyst, its preparation method, and its application. The present invention introduces a bifunctional organic small molecule ligand containing nitrogen and hydroxyl functional groups during the hydrolysis and precipitation of aluminum salts, and simultaneously introduces copper salts during the formation stage of the pseudoboehmite precursor. This allows the bifunctional ligand to coordinate and guide the hydrolysis, condensation, and lamellar assembly processes of aluminum species, while simultaneously enabling Cu… 2+ It co-precipitates in situ with aluminum species and disperses them in the precursor framework and pore structure. After aging, drying and calcination, it achieves synergistic regulation of the hierarchical pore structure construction of alumina support and the high dispersion loading of copper active species. It has the advantages of simple preparation process, no need for template agent, no need for additional auxiliary elements, high utilization rate of copper active sites, octenal hydrogenation activity and isooctyl alcohol selectivity, and has good prospects for industrial application.

[0008] The first aspect of this invention provides a copper-based octenal hydrogenation catalyst, comprising a hierarchical porous alumina support and copper species; The hierarchical porous alumina support is formed by calcining a pseudoboehmite precursor, and the copper species are formed by Cu during the pseudoboehmite precursor formation stage. 2+ With Al 3+ The copper species are formed by in-situ co-precipitation and calcination, and are dispersed in the pseudoboehmite precursor framework and pore structure. The multi-level porous alumina carrier has a multi-level pore structure composed of mesopores, interlayer pores, and interparticle pores.

[0009] A second aspect of the present invention provides a method for preparing the above-mentioned copper-based octenal hydrogenation catalyst, comprising the following steps: S1. Dissolve the aluminum salt in deionized water to form an aluminum precursor solution and stir. S2. Add a small organic molecule bifunctional ligand containing nitrogen and hydroxyl functional groups to the aluminum precursor solution, stir, and Al 3+ The molar ratio of the bifunctional ligand to the ligand is 1:(0.01-0.1), and then a copper salt solution is added to make Al 3+ With Cu 2+ The molar ratio was 1:(0.1-0.4), and the stirring rate and reaction temperature were kept constant; then an alkaline solution was added dropwise to adjust the endpoint pH to 8.0-10.0, so that Al 3+ Controlled hydrolysis, while simultaneously causing Cu 2+Simultaneous precipitation was carried out while maintaining a constant stirring rate and reaction temperature. After precipitation, the reaction temperature was maintained for aging, followed by filtration and washing until the conductivity of the filtrate was less than 30 µS / cm to obtain a filter cake. S3. The filter cake is dried to obtain a highly dispersed copper-based hierarchical porous boehmite precursor. Then, the highly dispersed copper-based hierarchical porous boehmite precursor is heat-treated to obtain the copper-based octenal hydrogenation catalyst.

[0010] Preferably, in step S1, the aluminum salt is one or more of aluminum sulfate, aluminum nitrate nonahydrate, or aluminum chloride; the concentration of the aluminum precursor solution is 0.5 mol / L; the stirring temperature is 65-90℃, and the stirring rate is 400 r / min.

[0011] Preferably, in step S2, the dropping rate of the bifunctional ligand is 0.20 mL / min; the Al 3+ The molar ratio of the bifunctional ligand to the ligand is 1:0.05; the nitrogen- and hydroxyl-functional organic small molecule bifunctional ligand is one or more of triethanolamine, 3-amino-1-propanol, or 4-hydroxypyridine; the copper salt is one or more of copper nitrate trihydrate, copper acetate monohydrate, or copper chloride; the concentration of the copper salt solution is 0.1 mol / L; the dropping rate of the alkaline solution is 0.1 mL / min; the concentration of the alkaline solution is 1.0 mol / L, and the base in the alkaline solution is one or more of NaOH, KOH, or Na2CO3; the reaction temperature is 80℃; the endpoint pH is 8.0; and the aging time is 6-18 h, more preferably 12 h.

[0012] Preferably, in step S3, the drying temperature is 120°C and the drying time is 24 h; the heat treatment is: heating from 30°C to 450°C at a heating rate of 10°C / min, and holding at 450°C for 4 h.

[0013] The third aspect of this invention provides the application of the above-mentioned copper-based octenal hydrogenation catalyst in the hydrogenation of octenal to prepare isooctanol.

[0014] Preferably, the octenal hydrogenation is carried out in a fixed-bed reactor, and the steps are as follows: the catalyst is ground and sieved to 60-100 mesh, then mixed with quartz sand at a mass ratio of 1:2 and loaded into the reactor, with a hydrogen gas integral of 20%, a balance gas of N2, and a volume hourly space velocity of 1000 h⁻¹. -1 In an atmosphere, the temperature was increased from 30℃ to 320℃ at a heating rate of 10℃ / min and held at 320℃ for 2 h for reduction, followed by natural cooling to the reaction temperature of 175±5℃; the reaction pressure for octenal hydrogenation was 2.4 MPa, the isooctanol / octenal ratio was 16.5:1, and the octenal mass hourly space velocity was 1.2 h⁻¹.-1 The hydrogen-aldehyde ratio was 2.2:1, and the reaction time was 4 h.

[0015] Compared with the prior art, the beneficial technical effects of the present invention are as follows: This invention introduces a bifunctional organic small molecule ligand containing nitrogen and hydroxyl functional groups during the hydrolysis and precipitation process of aluminum precursors, enabling the bifunctional ligand to react with Al. 3+ Coordination occurs, regulating the hydrolysis rate, condensation process, and growth and assembly of the pseudoboehmite sheets, thus avoiding the problem of a single pore structure caused by the disordered stacking of traditional pseudoboehmite sheets. After calcination, the resulting alumina support forms a multi-level pore structure composed of interlayer pores, mesopores, and interparticle pores, which can improve the diffusion and mass transfer of octenal, hydrogen, and hydrogenation products within the catalyst, increase the accessibility of active sites, and help reduce the formation of incomplete hydrogenation byproducts and heavy component byproducts.

[0016] This invention introduces copper components during the formation stage of the pseudoboehmite precursor, enabling Cu... 2+ Simultaneously with aluminum species participating in skeleton construction and pore formation during precipitation, copper species are no longer merely distributed on the outer surface or pores of the carrier via subsequent loading. Instead, they are more uniformly dispersed and anchored within the precursor skeleton and pore structure. After subsequent drying and calcination, the copper species form active components with smaller particle size, uniform distribution, and strong binding to the alumina carrier. This effectively inhibits the migration and aggregation of copper species during calcination, reduction, and reaction processes, thereby increasing the specific surface area of ​​copper and the utilization rate of copper active sites.

[0017] This invention eliminates the need for template agents, surfactants, or additional auxiliary elements. It achieves synergistic regulation of multi-level structure construction of pseudoboehmite precursors and high dispersion of copper active components solely through small molecule bifunctional ligands containing nitrogen and hydroxyl functional groups. This avoids the template agent removal step, simplifies the preparation process, reduces preparation costs and environmental burden, and demonstrates good feasibility for industrial scale-up.

[0018] This invention can significantly improve the dispersibility of copper species and the utilization rate of copper active sites. Within the preparation conditions defined in this invention, the conversion rate of octenal is 98.8%-99.9%, the yield of isooctanol is 96.8%-98.2%, and the selectivity of isooctanol is 97.61%-98.39%, making it suitable for the efficient hydrogenation of octenal to prepare isooctanol. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings.

[0020] Figure 1The images show the morphology of the highly dispersed copper-based hierarchical porous boehmite precursor prepared in this invention; where (a)-(c) are scanning electron microscope images at different magnifications, and (d) is a transmission electron microscope image. Figure 2 The X-ray diffraction patterns of Example 12, Comparative Example 13, and the γ-Al2O3 support are shown below. Figure 3 This is a comparison diagram of the pore size distribution of the catalysts obtained in Example 12 and Comparative Example 13. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] Unless otherwise stated, all experiments were repeated three times, and the results are expressed as averages.

[0023] Example 1: A method for preparing a copper-based octenal hydrogenation catalyst, comprising the following steps: Weigh 37.50 g of aluminum nitrate nonahydrate and dissolve it in 200 mL of deionized water to form an aluminum precursor solution with a concentration of 0.5 mol / L. Stir the solution at a reaction temperature of 65℃, and add 0.746 g of triethanolamine at a rate of 0.20 mL / min to ensure complete complexation of the ligand with the aluminum ions. 3+ The molar ratio of the ligand to the ligand was 1:0.05, and stirring was continued for 30 min. After the ligand and aluminum ions formed a stable complex system, 200 mL of the above 0.1 mol / L copper nitrate solution was added. The copper nitrate solution was obtained by dissolving 4.83 g of copper nitrate trihydrate in 200 mL of deionized water. 3+ With Cu 2+ The molar ratio is 1:0.2. Add 1.0 mol / L NaOH solution dropwise to the above solution at a rate of 30 mL / min to adjust the pH to 3.5, then adjust the pH to 5.0 at a rate of 10 mL / min, and finally adjust the pH to 8.0 at a rate of 0.1 mL / min, so that Al... 3+ Controlled hydrolysis, while simultaneously causing Cu 2+ Simultaneous precipitation. The mixture was aged at the reaction temperature for another 12 h, filtered, washed, and the filter cake was dried at 120 °C for 24 h, then calcined at 450 °C for 4 h to obtain the copper-based octenal hydrogenation catalyst.

[0024] Example 2 The difference from Example 1 is that the reaction temperature is 85°C.

[0025] Example 3 The difference from Example 1 is that the reaction temperature is 80°C; 0.1492 g of triethanolamine is added; Al 3+ The molar ratio of the ligand to the ligand is 1:0.01.

[0026] Example 4 The difference from Example 1 is that the reaction temperature is 80°C; 1.492 g of triethanolamine is added; Al 3+ The molar ratio of the ligand to the ligand is 1:0.1.

[0027] Example 5 The difference from Example 1 is that the reaction temperature is 80°C; Al 3+ With Cu 2+ The molar ratio is 1:0.1; the mass of copper nitrate trihydrate is 2.415 g.

[0028] Example 6 The difference from Example 1 is that the reaction temperature is 80°C; Al 3+ With Cu 2+ The molar ratio is 1:0.4; the mass of copper nitrate trihydrate is 9.66 g.

[0029] Example 7 The difference from Example 1 is that the reaction temperature is 80°C and the pH is 9.0.

[0030] Example 8 The difference from Example 1 is that the reaction temperature is 80°C and the pH is 10.0.

[0031] Example 9 The difference from Example 1 is that the reaction temperature is 80°C and the aging time is 6 hours.

[0032] Example 10 The difference from Example 1 is that the reaction temperature is 80°C and the aging time is 18 h.

[0033] Example 11 The difference from Example 1 is that the reaction temperature is 80°C; the ligand is a 4-hydroxypyridine solution with a mass fraction of 15% and the amount of ligand used is 3.173 g.

[0034] Example 12 The difference from Example 1 is that the reaction temperature is 80°C; the ligand is 3-amino-1-propanol; and the amount of ligand used is 0.375 g.

[0035] Example 13 The difference from Example 1 is that the reaction temperature is 80°C; the copper precursor is copper acetate monohydrate, and the added mass is 3.99g.

[0036] Example 14 The difference from Example 1 is that the reaction temperature is 80°C; the copper precursor is copper chloride, and the added mass is 2.689g.

[0037] Example 15 The difference from Example 1 is that the reaction temperature is 80°C and the alkaline solution used to adjust the pH is a 1.0 mol / L KOH solution.

[0038] Example 16 The difference from Example 1 is that the reaction temperature is 80°C; the aluminum precursor is aluminum chloride, and the added mass is 13.33g.

[0039] Comparative Example 1 The difference from Example 1 is that the reaction temperature is 50°C.

[0040] Comparative Example 2 The difference from Example 1 is that the reaction temperature is 95°C.

[0041] Comparative Example 3 The difference from Example 1 is that the reaction temperature is 80°C; 0.0746 g of triethanolamine is added; Al 3+ The molar ratio of the ligand to the ligand is 1:0.005.

[0042] Comparative Example 4 The difference from Example 1 is that the reaction temperature is 80°C; 2.984 g of triethanolamine is added; Al 3+ The molar ratio of the ligand to the ligand is 1:0.2.

[0043] Comparative Example 5 The difference from Example 1 is that the reaction temperature is 80°C; Al 3+ With Cu 2+ The molar ratio is 1:0.05; the mass of copper nitrate trihydrate is 1.208 g.

[0044] Comparative Example 6 The difference from Example 1 is that the reaction temperature is 80°C; Al 3+ With Cu 2+ The molar ratio is 1:0.6; the mass of copper nitrate trihydrate is 14.49 g.

[0045] Comparative Example 7 The difference from Example 1 is that the reaction temperature is 80°C and the pH is 7.0.

[0046] Comparative Example 8 The difference from Example 1 is that the reaction temperature is 80°C and the pH is 11.0.

[0047] Comparative Example 9 The difference from Example 1 is that the reaction temperature is 80°C and the aging time is 4 hours.

[0048] Comparative Example 10 The difference from Example 1 is that the reaction temperature is 80°C and the aging time is 24 h.

[0049] Comparative Example 11 The difference from Example 1 is that the reaction temperature is 80°C; the ligand is glycerol, and the amount used is 0.46 g.

[0050] Comparative Example 12 The difference from Example 1 is that the reaction temperature is 80°C; the ligand is ethylenediamine, and the amount used is 0.3 g.

[0051] Comparative Example 13 The difference from Example 1 is as follows: the reaction temperature is 80℃; the ligand is 3-amino-1-propanol, and the amount used is 0.375 g; 4.83 g of copper nitrate trihydrate was not added during the preparation of the support, but was calcined at 450℃ and then copper was loaded onto the support by impregnation method, and then calcined at 450℃ to obtain a copper catalyst supported on which only Al was modified by bifunctional ligand; the specific conditions of the impregnation method are as follows: 4.83 g of copper nitrate trihydrate was dissolved in 20.0 mL of deionized water to prepare copper nitrate impregnation solution; 5.1 g of Al2O3 support modified only by bifunctional ligand was weighed and added to the copper nitrate impregnation solution, impregnated at 60℃ for 3 h, and then dried at 120℃ for 24 h.

[0052] Comparative Example 14 The difference from Example 1 is that triethanolamine is not added, copper nitrate solution is added directly to the aluminum precursor solution, and NaOH solution is added dropwise under the same conditions to adjust the final pH. Then, aging, filtration, washing, drying and calcination are carried out. The remaining steps and conditions are the same as in Example 1, and a copper-aluminum coprecipitation catalyst without bifunctional ligands is obtained.

[0053] Comparative Example 15 Using γ-Al₂O₃ as the support powder, 5.1 g of it was weighed, and 4.83 g of copper nitrate trihydrate was dissolved in 20.0 mL of deionized water to prepare a copper nitrate impregnation solution. The γ-Al₂O₃ support was added to the copper nitrate impregnation solution and impregnated at 60°C for 3 h, followed by drying at 120°C for 24 h and calcination at 450°C for 4 h to obtain a conventional γ-Al₂O₃ supported copper catalyst. The copper content in the catalyst was the same as in Example 1.

[0054] Comparative Example 16 Using boehmite microspheres as a precursor, the microspheres were dried at 120°C for 24 h, then heated from 30°C to 450°C at a rate of 10°C / min and held at 450°C for 4 h to obtain a boehmite-derived Al2O3 support. 5.1 g of the above support was weighed, and 4.83 g of copper nitrate trihydrate was dissolved in 20.0 mL of deionized water to obtain a copper nitrate impregnation solution. The boehmite-derived alumina support was added to the copper nitrate impregnation solution and impregnated at 60°C for 3 h, followed by drying at 120°C for 24 h, and then calcining at 450°C for 4 h. The copper content in the resulting catalyst was the same as in Example 1, thus obtaining a boehmite-derived Al2O3 supported copper catalyst.

[0055] Comparative Example 1 BASF DPT101 aldehyde hydrogenation catalyst.

[0056] Comparative Example 2 Johnson Matthey CuAl catalyst for aldehyde hydrogenation.

[0057] Structural characterization and performance evaluation Figure 1 SEM results showed that the bifunctional ligand-induced hierarchical pseudoboehmite formed a loose spherical structure; TEM results showed that the pseudoboehmite still maintained the nanosheet characteristics, but the layers formed relatively rich stacked pores and interlayer channels, thus constructing a hierarchical pore structure composed of mesopores and interparticle pores.

[0058] Figure 2 The XRD results show that the copper species diffraction peaks in the catalyst obtained in this invention have a larger half-width, indicating that the copper particles are smaller and more dispersed. Figure 3 The difference in pore size distribution between Example 12 and Comparative Example 12 is shown.

[0059] The specific surface area, pore volume, CuO grain size, and copper specific surface area of ​​different catalysts are shown in Table 1.

[0060] Table 1. Specific surface area, pore volume, CuO grain size, and copper specific surface area of ​​different catalysts

[0061] Note: The specific surface area of ​​copper was obtained by N2O titration.

[0062] The catalysts prepared in Examples 1-16, Comparative Examples 1-16, and Comparative Examples 1 and 2 were evaluated in a fixed-bed reactor. A certain mass of catalyst, ground and sieved to 60-100 mesh, was mixed with quartz sand at a mass ratio of 1:2 and packed into the reactor. Reduction was carried out under a hydrogen atmosphere with a hydrogen volume fraction of 20%, N2 as the equilibrium gas, and a volume hourly space velocity of 1000 h⁻¹. -1 The heating rate was 10℃ / min, increasing the temperature from 30℃ to 320℃, and then holding at 320℃ for 2 hours before naturally cooling to the reaction temperature of 175±5℃. When the copper content in the catalyst varied, the catalyst mass was adjusted to ensure that the total copper content was the same, approximately 0.16 g (calculated as copper oxide). The catalyst masses were as follows: Example 5: 1.18 g; Example 6: 0.415 g; Comparative Example 5: 2.20 g; Comparative Example 6: 0.33 g; and the remaining examples, comparative examples, and comparative examples were all 0.67 g. The reaction was conducted at a pressure of 2.4 MPa, a temperature of 175±5℃, an isooctanol / octenal molar ratio of 16.5:1, and an octenal mass hourly space velocity of 1.2 h⁻¹. -1 Under the condition of a hydrogen-aldehyde ratio of 2.2:1, the reaction was carried out for 4 h. After the reaction stabilized, the liquid product was collected, and the conversion rate of octenal and the selectivity of by-products were analyzed by gas chromatography. The results are shown in Table 2.

[0063] Table 2. Catalytic performance evaluation results

[0064] Note: EHA, byproduct 2-ethylhexanal; ENOL, byproduct 2-ethylhexenol.

[0065] As can be seen from the data in Table 2, within the conditions of this invention, Examples 1-16 all exhibited excellent and stable catalytic performance: the conversion rate of octenal reached 98.8%-99.9%, close to complete conversion, while the yield of isooctanol remained stable at 96.8%-98.2%, and the selectivity of isooctanol remained at 97.61%-98.39%, which was significantly better than the catalyst performance of the comparative example and also better than the imported catalyst.

[0066] Further analysis revealed that the amount of ligand, the metal ratio, and the reaction conditions significantly affected the catalytic performance. Specifically, when the amount of ligand was too low, as in Comparative Example 3, insufficient regulation of aluminum species hydrolysis and structural growth led to a significant decrease in conversion and yield. Conversely, when the amount of ligand was too high, as in Comparative Example 4, excessive complexation inhibited the precipitation process, resulting in a significant enhancement of side reactions, particularly a marked increase in the incomplete hydrogenation byproduct ENOL. When Al... 3+ / Cu 2+When the molar ratio deviates from the range of this invention, such as in Comparative Examples 5 and 6, the number and dispersibility of active sites decrease, leading to a reduction in performance. Regarding reaction conditions, a pH deviation from the 8-10 range, such as in Comparative Examples 7 and 8, affects the controllability of the co-precipitation process, resulting in incomplete or non-uniform structures. An aging time that is too short or too long, such as in Comparative Examples 9 and 10, may lead to insufficient structural development or grain growth, both of which are detrimental to improving catalytic performance. Furthermore, using non-bifunctional ligands (Comparative Examples 11 and 12) or without ligand regulation (Comparative Example 14), without the synergistic effect of "coordination regulation-structure guidance," it is difficult to obtain high-performance catalysts. When copper is not added during support preparation, whether using Al2O3 supports modified only by bifunctional ligands (Comparative Example 13), traditional γ-Al2O3 powder supports (Comparative Example 15), or pseudoboehmite microspheres as Al2O3 support precursors (Comparative Example 16), the poor dispersibility of copper leads to a decrease in catalytic activity.

[0067] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A copper-based octenal hydrogenation catalyst, characterized in that, The aluminum salt solution was complexed with a bifunctional organic small molecule ligand containing nitrogen and hydroxyl functional groups and then introduced into a copper salt. Under alkaline conditions, the aluminum species were hydrolyzed in a controlled manner and co-precipitated in situ with the copper species. The solution was then subjected to aging, filtration, washing, drying and calcination. The copper-based octenal hydrogenation catalyst comprises a hierarchical porous alumina support and copper species. The hierarchical porous alumina support is formed by calcining a pseudoboehmite precursor, and the copper species are formed by Cu during the pseudoboehmite precursor formation stage. 2+ With Al 3+ The copper species are formed by in-situ co-precipitation and calcination, and are dispersed in the pseudoboehmite precursor framework and pore structure. The multi-level porous alumina carrier has a multi-level pore structure composed of mesopores, interlayer pores, and interparticle pores.

2. The method for preparing the copper-based octenal hydrogenation catalyst according to claim 1, characterized in that, Includes the following steps: S1. Dissolve the aluminum salt in deionized water to form an aluminum precursor solution and stir. S2. Add a small organic molecule bifunctional ligand containing nitrogen and hydroxyl functional groups to the aluminum precursor solution, stir, and Al 3 + The molar ratio of the bifunctional ligand to the ligand is 1:(0.01-0.1), and then a copper salt solution is added to make Al 3+ With Cu 2+ The molar ratio was 1:(0.1-0.4), and the stirring rate and reaction temperature were kept constant; then an alkaline solution was added dropwise to adjust the endpoint pH to 8.0-10.0, so that Al 3+ Controlled hydrolysis, while simultaneously causing Cu 2+ Simultaneous precipitation was carried out while maintaining a constant stirring rate and reaction temperature. After precipitation, the reaction temperature was maintained for aging, followed by filtration, washing, and obtaining a filter cake. S3. The filter cake is dried to obtain a highly dispersed copper-based hierarchical porous boehmite precursor. Then, the highly dispersed copper-based hierarchical porous boehmite precursor is heat-treated to obtain the copper-based octenal hydrogenation catalyst.

3. The preparation method according to claim 2, characterized in that, In step S1, the aluminum salt is one or more of aluminum sulfate, aluminum nitrate nonahydrate, or aluminum chloride.

4. The preparation method according to claim 2, characterized in that, In step S2, the Al 3+ The molar ratio of the bifunctional ligand to the ligand is 1:0.05; the nitrogen- and hydroxyl-functional organic small molecule bifunctional ligand is one or more of triethanolamine, 3-amino-1-propanol or 4-hydroxypyridine; the copper salt is one or more of copper nitrate trihydrate, copper acetate monohydrate or copper chloride; the concentration of the copper salt solution is 0.1 mol / L.

5. The preparation method according to claim 2, characterized in that, In step S2, the reaction temperature is 80°C, the endpoint pH is 8.0, and the aging time is 6-18 h.

6. The preparation method according to claim 5, characterized in that, In step S2, the aging time is 12 hours.

7. The preparation method according to claim 5, characterized in that, In step S3, the heat treatment is as follows: the temperature is increased from 30°C to 450°C at a heating rate of 10°C / min, and then held at 450°C for 4 hours.

8. The application of the copper-based octenal hydrogenation catalyst of claim 1 in the hydrogenation of octenal to prepare isooctanol.

9. The application according to claim 8, characterized in that, The hydrogenation of octenal is carried out in a fixed-bed reactor.

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