A composite non-noble metal catalyst, its preparation method and application

Abstract

This invention relates to the field of catalytic material preparation technology, specifically disclosing a composite non-precious metal catalyst, its preparation method, and its applications. The support for the composite non-precious metal catalyst is a solid solution formed from alumina and alkaline earth metal oxides, and the active component is selected from at least two of Cu, Ni, or Co. This invention successfully prepares a series of composite non-precious metal catalysts in solid solution state through a simple co-precipitation method, calcination, and reduction method. By controlling the mass ratio of alkaline earth metals in the support and adjusting the acidity / alkalinity of the support, the forward amination reaction is promoted during the reaction. Simultaneously, the synergistic effect between alumina and alkaline earth metals, as well as the synergistic effect between specific binary non-precious metal active components, significantly improves the selectivity of the hexanediamine reduction amination reaction, effectively reduces the occurrence of side reactions, and significantly reduces the production cost of the catalyst, which is of great significance for the large-scale production of hexanediamine.

Description

Technical Field

[0001] This invention relates to the field of catalytic material preparation technology, and in particular to a composite non-precious metal catalyst, its preparation method, and its application. Background Technology

[0002] Hexamethylenediamine, also known as 1,6-hexamethylenediamine, is an important chemical intermediate that can be used in the synthesis of a variety of polymers and small organic molecules. Its main products include polyamides such as nylon 66 and nylon 610, hexamethylene diisocyanate, and curing agents and organic crosslinking agents used in urea-formaldehyde resins and epoxy resins. Its synthesis technology and industrial production have always attracted widespread attention.

[0003] Currently, the main method for large-scale production of hexamethylenediamine is the adiponitrile hydrogenation process. Adiponitrile catalytic hydrogenation processes are divided into high-pressure and low-pressure methods. The high-pressure method places extremely high demands on equipment, while the low-pressure method uses nickel-based catalysts, but requires strong alkaline compounds as co-catalysts to improve the activity of the main catalyst. The added strong alkaline compounds cause significant corrosion to equipment and are difficult to separate from the product, greatly limiting their application in hexamethylenediamine production. Furthermore, the high price of the raw material adiponitrile severely impacts the economic benefits and market competitiveness of the nylon industry, hindering the development of related nylon industries.

[0004] Hexanediamine can be prepared from 1,6-hexanediol via hydroammoniation. Hexanediol can be prepared by catalytic hydrogenation from adipic acid, dimethyl adipic acid, and the bio-based platform compound 5-hydroxymethylfurfural, among other raw materials, making the process widely available and environmentally friendly. Therefore, the preparation of hexanediamine using the hexanediol method has attracted considerable attention in recent years. Currently, catalysts used in the hydroammoniation of hexanediamine suffer from problems such as the presence of numerous byproducts and insufficient selectivity of the main product for industrial production. To improve the catalyst's reactivity and selectivity, noble metals (such as Pd, Pt, Ru, etc.) are typically added as promoters, or the support is ammonified or alkali-treated. However, this process is cumbersome and costly. Summary of the Invention

[0005] To address the problems of poor selectivity, high cost, and cumbersome preparation of catalysts used in the amination of hexanediamine from hexanediol in the prior art, this invention provides a composite non-precious metal catalyst, its preparation method, and its application.

[0006] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0007] In a first aspect, the present invention provides a composite non-precious metal catalyst comprising a binary metal oxide support and a metal active component supported on the binary metal oxide support; wherein the binary metal oxide support is a solid solution formed of alumina and alkaline earth metal oxides, and the metal active component is selected from at least two of Cu, Ni or Co.

[0008] Compared to existing technologies, the composite non-precious metal catalyst provided by this invention includes a non-precious metal active component and a solid solution support formed by alumina and alkaline earth metal oxides. The alkaline earth metal oxides in the solid solution can improve the basicity of the catalyst, and their synergistic effect with alumina can promote the forward reductive amination reaction while inhibiting the formation of side reactions. Furthermore, the binary metal oxides in the solid solution state interact with the non-precious metal binary active component to improve the stability and catalytic activity of the active metal component. Applying this catalyst to the reductive amination of hexanediamine from hexanediol can significantly improve the selectivity of the reaction and increase the yield of hexanediamine, thereby enhancing the economic benefits and market competitiveness of the nylon industry and promoting the development of related nylon industries.

[0009] Furthermore, existing technologies, in order to improve the catalytic activity of catalysts for the reductive amination of hexanediamine from hexanediol, generally require the addition of noble metals as co-activating components, the addition of strong base co-catalysts during the catalytic reaction stage, or ammoniation treatment of the catalyst support. These methods suffer from high preparation costs, cumbersome processes, and the inability to precisely control the basicity of the support. This invention, by using a solid solution formed from alkaline earth metal oxides and alumina as a support, not only improves the basicity of the support but also facilitates precise control of its basicity. Simultaneously, the synergistic effect between alumina and alkaline earth metals, as well as the synergistic effect between specific binary non-noble metal active components, significantly improves the selectivity of the reductive amination of hexanediamine, resulting in a catalyst with excellent catalytic activity and selectivity, effectively reducing the occurrence of side reactions, and significantly lowering the production cost of the catalyst. This is of great significance for the large-scale production of hexanediamine.

[0010] Furthermore, the active metal component is CuNi, CuCo, or CoNi.

[0011] Preferably, the alkaline earth metal oxide is an oxide corresponding to Mg, Ca, Sr or Ba.

[0012] The binary metal oxide supports in the solid solution state are MgO-Al2O3, CaO-Al2O3, SrO-Al2O3, and BaO-Al2O3.

[0013] The selection of preferred metal active components and alkaline earth elements can enable the catalyst to have good catalytic activity, improve the selectivity of the hexanediamine reduction reaction, and reduce the occurrence of side reactions.

[0014] Preferably, the alkaline earth metal oxide accounts for 5% to 50% of the total mass of the catalyst.

[0015] More preferably, the metal oxide accounts for 5% to 15% of the total mass of the catalyst.

[0016] Preferably, the loading of the metal active component is 1% to 20% of the total mass of the catalyst.

[0017] The optimal content of the active metal component and each metal oxide in the catalyst can enable the active component and the support to synergistically achieve the best catalytic activity, as well as the two metal oxides on the support.

[0018] This invention also provides a method for preparing a composite non-noble metal catalyst, comprising at least the following steps:

[0019] A precursor of alumina, a precursor of alkaline earth metal oxide, and a precursor of metal active component are dissolved in water to obtain a catalyst precursor solution. A precipitant is added to the catalyst precursor solution to adjust the pH of the system to 8-11, and a co-precipitation reaction is carried out. The solid and liquid are separated, dried, calcined, and reduced to obtain a composite non-precious metal catalyst.

[0020] This invention uses a simple chemical coprecipitation method to prepare composite non-precious metal catalysts. The method is simple to operate, has high production efficiency, and is suitable for large-scale production applications.

[0021] Specifically, the catalyst provided by this invention comprises: CuNi / MgO-Al2O3, CuNi / CaO-Al2O3, CuNi / SrO-Al2O3, and CuNi / BaO-Al2O3. 3、 CuCo / MgO-Al2O3, CuCo / CaO-Al2O3, CuCo / SrO-Al2O3, CoNi / BaO-Al2O3, CuCo / BaO-Al2O3.

[0022] In one specific embodiment of the present invention, the precursors of alumina, alkaline earth metal oxides, and metal active components may be selected from nitrates, chlorides, acetates, oxalates, sulfates, citrates, or other soluble salts of the corresponding metal elements.

[0023] It should be noted that the solid obtained from solid-liquid separation is dried before calcination. The drying temperature is 80℃~120℃, preferably 90℃, and the drying time is 7h~14h, preferably 9h.

[0024] Preferably, the concentration of the catalyst precursor solution is 0.06 g / mL to 0.1 g / mL.

[0025] Preferably, the precipitant is at least one of ammonia, sodium carbonate, ammonium carbonate, or sodium hydroxide.

[0026] More preferably, the precipitant is ammonium carbonate.

[0027] Preferably, the temperature of the coprecipitation reaction is 50℃~100℃, and the time of the coprecipitation reaction is 4h~7h.

[0028] Preferably, the calcination temperature is 400℃~800℃ and the calcination time is 4h~7h.

[0029] More preferably, the calcination temperature is 400℃~600℃ and the calcination time is 4h~7h; more preferably, the calcination temperature is 500℃ and the calcination time is 5h.

[0030] Preferably, the temperature of the reduction reaction is 300℃~500℃, and the time of the reduction reaction is 1h~3h.

[0031] More preferably, the reduction reaction is carried out at a temperature of 400°C for 2 hours.

[0032] In one specific embodiment of the present invention, the reduction reaction is carried out in a hydrogen atmosphere.

[0033] This invention successfully prepared a series of composite non-precious metal catalysts in solid solution state through a simple co-precipitation, calcination, and reduction method. By introducing alkaline earth metal oxides into the alumina main component of the catalyst support to regulate the acidity and alkalinity of the support, the strong alkaline co-catalyst is eliminated from the need to be added during the catalytic reaction stage. At the same time, it avoids the cumbersome process and inability to accurately control the acidity and alkalinity of the support associated with conventional ammoniation or alkalization treatments. By controlling the mass ratio of alkaline earth metals in the support, the acidity and alkalinity of the support are modified, promoting the forward reaction of the ammoniation reaction during the reaction process, and effectively improving the selectivity of the hexanediamine preparation reaction from hexanediol.

[0034] Thirdly, the present invention also provides the application of the above-mentioned composite non-precious metal catalyst in the preparation of hexanediamine by the reductive amination of hexanediol.

[0035] The composite non-precious metal catalyst provided by this invention exhibits excellent catalytic activity, selectivity, and stability when applied to the reductive amination of hexanediamine from hexanediol, providing an excellent catalyst for the preparation of hexanediamine from hexanediol.

[0036] The main byproducts of the reductive amination of hexanediamine to produce hexanediamine are cyclohexylimine and aminohexanol. The composite non-precious metal catalyst provided by this invention can effectively suppress the formation of cyclohexylimine and aminohexanol, thereby improving the conversion rate of hexanediol.

[0037] Fourthly, the present invention provides a method for preparing hexanediamine, comprising the following steps: using hexanediol and ammonia as raw materials, and the above-mentioned composite non-precious metal catalyst as catalyst, a reductive amination reaction is carried out under a hydrogen atmosphere to obtain hexanediamine.

[0038] Specifically, the preparation method of the above-mentioned hexamethylenediamine includes the following steps:

[0039] Hexanediol, solvent, and catalyst were added to a high-pressure reactor, which was then sealed. The reactor was purged sequentially with nitrogen and then hydrogen to stabilize the hydrogen pressure in the final reaction system at 1.0 MPa to 3.0 MPa. The reactor was heated to 180°C to 220°C, and ammonia gas at 8 MPa to 12 MPa was pumped in. The reaction was carried out for 10 to 20 hours. The high-pressure reactor was then cooled to room temperature, the pressure was released, and the resulting mixture was filtered, washed, and dried to obtain hexanediamine.

[0040] Furthermore, the solvent is tert-butanol.

[0041] Furthermore, the ratio of hexanediol to catalyst is (10-20) mmol:(0.1-0.2) g, preferably 20 mmol:0.2 g.

[0042] Further, the ratio of solvent to catalyst is (20-40) mL:(0.1-0.2) g, preferably 30 mL:0.2 g.

[0043] In one specific embodiment of the present invention, a reductive amination reaction is carried out under stirring conditions.

[0044] Furthermore, the reaction temperature for the above-mentioned reductive amination is 190℃~200℃, and the reaction time is 12h~24h, preferably 18h.

[0045] Compared with existing technologies, the composite non-precious metal catalyst provided by this invention uses a binary metal oxide solid solution as a support. The alkaline earth metal oxide can effectively modulate the acidity and alkalinity of the support. The interaction between the binary metal oxide in the solid solution state and the multi-component non-precious metal active components can further improve the activity and stability of the active metal center. When applied to the reaction of hexanediamine preparation by the reductive amination of hexanediol, it exhibits excellent activity, selectivity and stability, effectively reducing the formation of cyclohexylimine and aminohexanol during the reaction, thereby significantly improving the conversion rate of hexanediol. Moreover, the catalyst preparation method is simple, environmentally friendly and low in cost, and has broad application prospects in the field of hexanediamine preparation. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0047] In the following examples, the metal salts used, if available in hydrate form, are all in hydrated form.

[0048] Example 1

[0049] This embodiment provides a method for preparing a CuNi / MgO-Al2O3 catalyst:

[0050] 1.44 g copper nitrate, 1.25 g nickel nitrate, 4.8 g magnesium nitrate, and 12.6 g aluminum nitrate were dissolved in 200 mL deionized water and heated to 80 °C. While stirring vigorously, 100 mL of ammonium carbonate solution (containing 20.8 g ammonium carbonate) was added dropwise. The pH was adjusted to 9, and the mixture was stirred for 5 h. After cooling to room temperature, the mixture was filtered, washed, and the filter cake was dried overnight at 90 °C. The cake was then ground uniformly and calcined in a muffle furnace at 500 °C for 5 h in air. Before use, it was reduced at 400 °C for 2 h in hydrogen atmosphere to obtain the CuNi / MgO-Al2O3 catalyst.

[0051] The CuNi / MgO-Al2O3 catalyst prepared above was applied to the hexanediamine reduction amination reaction, and the catalytic performance of the catalyst was measured.

[0052] 20 mmol (2.36 g) of hexanediol, 30 mL of tert-butanol, and 0.2 g of CuNi / MgO-Al2O3 catalyst were added to a 100 mL autoclave. The autoclave was sealed, and the system was purged sequentially with nitrogen and then hydrogen to stabilize the hydrogen pressure at 1 MPa. After heating to 200 °C, 10 MPa of ammonia was pumped in. The reaction was allowed to proceed for 12 h, after which stirring was stopped, the autoclave was cooled to room temperature, and the pressure was released. The resulting mixture was filtered, and the filtrate was analyzed by gas chromatography. The conversion and yield were calculated based on the molar amounts of each component in the mixture. Gas chromatography was performed using an HP-5 capillary column, an FID detector, and n-octanol as an internal standard for quantitative analysis. The results are shown in Table 1.

[0053] The conversion rate of hexanediol and the selectivity of hexanediamine were calculated using the following formula:

[0054]

[0055]

[0056] Example 2

[0057] This embodiment provides a method for preparing a CuNi / CaO-Al2O3 catalyst:

[0058] 1.44 g copper nitrate, 1.25 g nickel nitrate, 4.4 g calcium nitrate, and 12.6 g aluminum nitrate were dissolved in 200 mL deionized water and heated to 80 °C. While stirring vigorously, 100 mL of ammonium carbonate solution (containing 20.8 g ammonium carbonate) was added dropwise. The pH was adjusted to 9, and the mixture was stirred for 5 h. After cooling to room temperature, the mixture was filtered, washed, and the filter cake was dried overnight at 90 °C. The cake was then ground uniformly and calcined in a muffle furnace at 500 °C for 5 h in air. Before use, the cake was reduced at 400 °C for 2 h in hydrogen atmosphere to obtain the CuNi / MgO-Al2O3 catalyst.

[0059] The CuNi / CaO-Al2O3 catalyst prepared above was applied to the hexanediamine reduction amination reaction, and its performance was tested using the same method as in Example 1. The results are shown in Table 1.

[0060] Example 3

[0061] This embodiment provides a method for preparing a CuNi / SrO-Al2O3 catalyst:

[0062] 1.44 g copper nitrate, 1.25 g nickel nitrate, 3.6 g strontium nitrate, and 12.6 g aluminum nitrate were dissolved in 200 mL deionized water and heated to 80 °C. While stirring vigorously, 100 mL of ammonium carbonate solution (containing 20.8 g ammonium carbonate) was added dropwise. The pH was adjusted to 9, and the mixture was stirred for 5 h. After cooling to room temperature, the mixture was filtered, washed, and the filter cake was dried overnight at 90 °C. The cake was then ground uniformly and calcined in a muffle furnace at 500 °C for 5 h in air. Before use, it was reduced at 400 °C for 2 h in hydrogen atmosphere to obtain the CuNi / SrO-Al2O3 catalyst.

[0063] The CuNi / SrO-Al2O3 catalyst prepared above was applied to the hexanediamine reduction amination reaction, and its performance was tested using the same method as in Example 1. The results are shown in Table 1.

[0064] Example 4

[0065] This embodiment provides a method for preparing a CuNi / BaO-Al2O3 catalyst:

[0066] 1.44 g copper nitrate, 1.25 g nickel nitrate, 3.5 g barium nitrate, and 12.6 g aluminum nitrate were dissolved in 200 mL of deionized water and heated to 80 °C. While stirring vigorously, 100 mL of ammonium carbonate solution (containing 20.8 g ammonium carbonate) was added dropwise. The pH was adjusted to 9, and the mixture was stirred for 5 h. After cooling to room temperature, the mixture was filtered, washed, and the filter cake was dried overnight at 90 °C. The cake was then ground uniformly and calcined in a muffle furnace at 500 °C for 5 h in air. Before use, the cake was reduced at 400 °C for 2 h in hydrogen atmosphere to obtain the CuNi / BaO-Al2O3 catalyst.

[0067] The CuNi / BaO-Al2O3 catalyst prepared above was applied to the hexanediamine reduction amination reaction, and its performance was tested using the same method as in Example 1. The results are shown in Table 1.

[0068] Example 5

[0069] This embodiment provides a method for preparing a CuCo / MgO-Al2O3 catalyst:

[0070] 1.44 g copper nitrate, 1.25 g cobalt nitrate, 4.8 g magnesium nitrate, and 12.6 g aluminum nitrate were dissolved in 200 mL of deionized water and heated to 80 °C. While stirring vigorously, 100 mL of ammonium carbonate solution (containing 20.8 g of ammonium carbonate) was added dropwise. The pH was adjusted to 9, and the mixture was stirred for 5 h. After cooling to room temperature, the mixture was filtered, washed, and the filter cake was dried overnight at 90 °C. The cake was then ground uniformly and calcined in a muffle furnace at 500 °C for 5 h in air. Before use, the cake was reduced at 400 °C for 2 h in hydrogen atmosphere to obtain the CuCo / MgO-Al2O3 catalyst.

[0071] The CuCo / MgO-Al2O3 catalyst prepared above was applied to the hexanediamine reduction amination reaction, and its performance was tested using the same method as in Example 1. The results are shown in Table 1.

[0072] Example 6

[0073] This embodiment provides a method for preparing a CuCo / CaO-Al2O3 catalyst:

[0074] 1.44 g copper nitrate, 1.25 g cobalt nitrate, 4.4 g calcium nitrate, and 12.6 g aluminum nitrate were dissolved in 200 mL of deionized water and heated to 80 °C. While stirring vigorously, 100 mL of ammonium carbonate solution (containing 20.8 g ammonium carbonate) was added dropwise. The pH was adjusted to 9, and the mixture was stirred for 5 h. After cooling to room temperature, the mixture was filtered, washed, and the filter cake was dried overnight at 90 °C. The cake was then ground uniformly and calcined in a muffle furnace at 500 °C for 5 h in air. Before use, the cake was reduced at 400 °C for 2 h in hydrogen atmosphere to obtain the CuCo / CaO-Al2O3 catalyst.

[0075] The CuCo / CaO-Al2O3 catalyst prepared above was applied to the hexanediamine reduction amination reaction, and its performance was tested using the same method as in Example 1. The results are shown in Table 1.

[0076] Example 7

[0077] This embodiment provides a method for preparing a CuCo / SrO-Al2O3 catalyst:

[0078] 1.44 g copper nitrate, 1.25 g cobalt nitrate, 3.6 g strontium nitrate, and 12.6 g aluminum nitrate were dissolved in 200 mL of deionized water and heated to 80 °C. While stirring vigorously, 100 mL of ammonium carbonate solution (containing 20.8 g ammonium carbonate) was added dropwise. The pH was adjusted to 9, and the mixture was stirred for 5 h. After cooling to room temperature, the mixture was filtered, washed, and the filter cake was dried overnight at 90 °C. The cake was then ground uniformly and calcined in a muffle furnace at 500 °C for 5 h in air. Before use, the cake was reduced at 400 °C for 2 h in hydrogen atmosphere to obtain the CuCo / SrO-Al2O3 catalyst.

[0079] The CuCo / SrO-Al2O3 catalyst prepared above was applied to the hexanediamine reduction amination reaction, and its performance was tested using the same method as in Example 1. The results are shown in Table 1.

[0080] Example 8

[0081] This embodiment provides a method for preparing a CuCo / BaO-Al2O3 catalyst:

[0082] 1.44 g copper nitrate, 1.25 g cobalt nitrate, 3.5 g barium nitrate, and 12.6 g aluminum nitrate were dissolved in 200 mL of deionized water and heated to 80 °C. While stirring vigorously, 100 mL of ammonium carbonate solution (containing 20.8 g of ammonium carbonate) was added dropwise. The pH was adjusted to 9, and the mixture was stirred for 5 h. After cooling to room temperature, the mixture was filtered, washed, and the filter cake was dried overnight at 90 °C. The cake was then ground uniformly and calcined in a muffle furnace at 500 °C for 5 h in air. Before use, the cake was reduced at 400 °C for 2 h in hydrogen atmosphere to obtain the CuCo / BaO-Al2O3 catalyst.

[0083] The CuCo / BaO-Al2O3 catalyst prepared above was applied to the hexanediamine reduction amination reaction, and its performance was tested using the same method as in Example 1. The results are shown in Table 1.

[0084] Example 9

[0085] This embodiment provides a method for preparing a CoNi / BaO-Al2O3 catalyst:

[0086] 1.25 g nickel nitrate, 1.25 g cobalt nitrate, 3.5 g barium nitrate, and 12.6 g aluminum nitrate were dissolved in 200 mL deionized water and heated to 90 °C. While stirring vigorously, 100 mL of ammonium carbonate solution (containing 20.8 g ammonium carbonate) was added dropwise. The pH was adjusted to 9, and the mixture was stirred for 4 h. After cooling to room temperature, the mixture was filtered, washed, and the filter cake was dried overnight at 90 °C. The cake was then ground uniformly and calcined in a muffle furnace at 800 °C for 4 h in air. Before use, the cake was reduced at 400 °C for 2 h in hydrogen atmosphere to obtain the CoNi / BaO-Al2O3 catalyst.

[0087] The CoNi / BaO-Al2O3 catalyst prepared above was applied to the hexanediamine reduction amination reaction, and its performance was tested using the same method as in Example 1. The results are shown in Table 1.

[0088] Example 10

[0089] This embodiment provides a method for preparing a CoCu / BaO-Al2O3-1 catalyst:

[0090] 0.22 g copper nitrate, 0.15 g cobalt nitrate, 0.2 g barium nitrate, and 12.6 g aluminum nitrate were dissolved in 200 mL of deionized water and heated to 60 °C. While stirring vigorously, 100 mL of ammonium carbonate solution (containing 20.8 g ammonium carbonate) was added dropwise. The pH was adjusted to 9, and the mixture was stirred for 7 h. After cooling to room temperature, the mixture was filtered, washed, and the filter cake was dried overnight at 90 °C. The cake was then ground uniformly and calcined in a muffle furnace at 400 °C for 7 h in air. Before use, the cake was reduced at 400 °C for 2 h in hydrogen atmosphere to obtain the CoCu / BaO-Al2O3-1 catalyst.

[0091] The CoCu / BaO-Al2O3-1 catalyst prepared above was applied to the hexanediamine reduction amination reaction, and its performance was tested using the same method as in Example 1. The results are shown in Table 1.

[0092] Comparative Example 1

[0093] This comparative example provides a method for preparing a CuCo / Al2O3 catalyst:

[0094] 1.44 g copper nitrate, 1.25 g cobalt nitrate, and 12.6 g aluminum nitrate hydrate were dissolved in 150 mL of deionized water. The mixture was heated to 80 °C and stirred vigorously. 67 mL of ammonium carbonate solution (13.9 g ammonium carbonate) was added dropwise to adjust the pH to 9. The mixture was stirred for 5 h, cooled to room temperature, filtered, washed, and the filter cake was dried at 90 °C for 9 h. The cake was then ground uniformly and calcined at 550 °C for 5 h in an air atmosphere in a muffle furnace. Before use, the cake was reduced at 400 °C for 2 h in a hydrogen atmosphere to obtain the CuCo / Al2O3 catalyst.

[0095] The CuCo / Al2O3 catalyst prepared above was applied to the hexanediamine reduction amination reaction, and its performance was tested using the same method as in Example 1. The results are shown in Table 1.

[0096] Comparative Example 2

[0097] This comparative example provides a method for preparing a CuFe / CaO-Al2O3 catalyst, comprising the following steps:

[0098] 1.44 g copper nitrate, 1.25 g ferric nitrate, 4.4 g calcium nitrate and 12.6 g aluminum nitrate were dissolved in 200 mL deionized water and heated to 80 °C. Under vigorous stirring, 100 mL ammonium carbonate solution (containing 20.8 g ammonium carbonate) was added dropwise to adjust the pH to 9. The mixture was stirred for 5 h, cooled to room temperature, filtered, washed, and the filter cake was dried overnight at 90 °C. The cake was then ground evenly and calcined in a muffle furnace at 500 °C for 5 h in air atmosphere. Before use, the cake was reduced at 400 °C for 2 h in hydrogen atmosphere to obtain the CuFe / CaO-Al2O3 catalyst.

[0099] The CuFe / CaO-Al2O3 catalyst prepared above was applied to the hexanediamine reduction amination reaction, and its performance was tested using the same method as in Example 1. The results are shown in Table 1.

[0100] Comparative Example 3

[0101] This comparative example provides a method for preparing a CuCo / MgO-Al2O3-1 catalyst, comprising the following steps:

[0102] 0.754 g MgO and 0.856 g Al2O3 were ground and mixed to obtain the MgO-Al2O3 support. 1.44 g copper nitrate and 1.25 g cobalt nitrate were dissolved in 50 mL deionized water and heated to 80 °C. Under vigorous stirring, 100 mL ammonium carbonate solution (containing 20.8 g ammonium carbonate) was added dropwise to adjust the pH to 9. The above MgO-Al2O3 support was then added, stirred for 5 h, cooled to room temperature, filtered, washed, and the filter cake was dried overnight at 90 °C. The cake was then ground uniformly and calcined in a muffle furnace at 500 °C for 5 h in air atmosphere. Before use, it was reduced at 400 °C for 2 h in hydrogen atmosphere to obtain the CuCo / MgO-Al2O3-1 catalyst.

[0103] The CuCo / MgO-Al2O3-1 catalyst prepared above was applied to the hexanediamine reduction amination reaction, and its performance was tested using the same method as in Example 1. The results are shown in Table 1.

[0104] Comparative Example 4

[0105] This comparative example provides a method for preparing a CuCo / MgO-Al2O3-2 catalyst, comprising the following steps:

[0106] 4.8 g magnesium nitrate and 12.6 g aluminum nitrate were dissolved in 150 mL deionized water, heated at 80 °C, and under vigorous stirring, 67 mL ammonium carbonate solution (13.9 g ammonium carbonate) was added dropwise to adjust the pH to 9. The mixture was stirred for 5 h, cooled to room temperature, filtered, washed, and the filter cake was dried at 90 °C for 9 h to obtain the MgO-Al2O3 precursor. 1.44 g copper nitrate and 1.25 g cobalt nitrate were dissolved in 50 mL deionized water, heated at 80 °C, and 33 mL ammonium carbonate solution (6.9 g) was added dropwise to adjust the pH to 9. The above MgO-Al2O3 precursor was added, stirred for 5 h, cooled to room temperature, filtered, washed, and the filter cake was dried at 90 °C for 9 h. The mixture was then calcined in a muffle furnace at 550 °C for 5 h in air atmosphere and reduced at 400 °C for 2 h in hydrogen atmosphere before use to obtain the CuCo / MgO-Al2O3-2 catalyst.

[0107] The CuCo / MgO-Al2O3-2 catalyst prepared above was used in the reductive amination of hexanediamine with hexanediol, and its performance was tested using the same method as in Example 1. The results are shown in Table 1.

[0108] Table 1. Reaction data for the preparation of hexanediamine by the reductive amination of hexanediol in the examples and comparative examples.

[0109]

[0110] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. The application of a composite non-noble metal catalyst in the reductive amination of hexanediamine from hexanediol, characterized in that, The composite non-precious metal catalyst comprises a binary metal oxide support and a metal active component supported on the binary metal oxide support; wherein the binary metal oxide support is a solid solution formed by alumina and alkaline earth metal oxides, and the metal active component is selected from at least two of Cu, Ni or Co; The alkaline earth metal oxide accounts for 5% to 50% of the total mass of the catalyst; the alkaline earth metal oxide is an oxide corresponding to Mg, Ca, Sr or Ba.

2. The application as described in claim 1, characterized in that, The alkaline earth metal oxides account for 5% to 15% of the total mass of the catalyst.

3. The application as described in claim 1, characterized in that, The loading of the metal active component is 1% to 20% of the total mass of the catalyst.

4. The application as described in claim 1, characterized in that, The preparation method of the composite non-noble metal catalyst includes at least the following steps: A precursor of alumina, a precursor of alkaline earth metal oxide, and a precursor of metal active component are dissolved in water to obtain a catalyst precursor solution. A precipitant is added to the catalyst precursor solution to adjust the pH of the system to 8-11, and a co-precipitation reaction is carried out. The solid and liquid are separated, dried, calcined, and reduced to obtain a composite non-precious metal catalyst.

5. The application as described in claim 4, characterized in that, The concentration of the catalyst precursor solution is 0.06 g / mL to 0.1 g / mL; and / or The precipitant is at least one of ammonia, sodium carbonate, ammonium carbonate, or sodium hydroxide; and / or The temperature of the coprecipitation reaction is 50℃~100℃, and the time of the coprecipitation reaction is 4h~7h.

6. The application as described in claim 4, characterized in that, The calcination temperature is 400℃~800℃, and the calcination time is 4h~7h; and / or The reduction reaction is carried out at a temperature of 300℃ to 500℃ for 1 hour to 3 hours.

7. A method for preparing hexamethylenediamine, characterized in that, The process includes the following steps: using hexanediol and ammonia as raw materials, and a composite non-precious metal catalyst as a catalyst, a reductive amination reaction is carried out under a hydrogen atmosphere to obtain hexanediamine; the composite non-precious metal catalyst includes a binary metal oxide support and a metal active component supported on the binary metal oxide support; wherein, the binary metal oxide support is a solid solution formed by alumina and alkaline earth metal oxides, and the metal active component is selected from at least two of Cu, Ni, or Co; The alkaline earth metal oxide accounts for 5% to 50% of the total mass of the catalyst; the alkaline earth metal oxide is an oxide corresponding to Mg, Ca, Sr or Ba.

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