Layered nickel-aluminum bimetallic oxide loaded bimetallic active component catalyst and preparation method thereof, and method for preparing primary amine by reductive amination of biomass carbonyl compound

Abstract

The invention discloses a layered nickel-aluminum bimetallic oxide loaded bimetallic active component catalyst and a preparation method thereof, and a method for preparing primary amine by reductive amination of a biomass carbonyl compound, and the catalyst is prepared by the following steps: calcining and reducing layered nickel-aluminum bimetallic hydroxide impregnated with noble metal M in a tubular furnace filled with N2 / H2 mixed gas at high temperature; the preparation method of the primary amine comprises the following steps: adding a biomass carbonyl compound, ammonia water, a catalyst and a solvent into a Schlenk glass tube or a reaction kettle, and carrying out reductive amination reaction in a hydrogen atmosphere to obtain the target product primary amine. The catalyst has the characteristics of high specific surface area and unique surface microenvironment effect, the catalytic activity and selectivity of the biomass carbonyl compound reductive amination reaction are improved, the preparation method of the primary amine is simple, the reaction process conditions are mild, the utilization of the renewable biomass carbonyl compound raw material is combined, and the production cost is reduced. And a green closed loop from raw materials to products can be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and relates to a supported metal catalyst, and specifically relates to a layered nickel-aluminum bimetallic oxide supported bimetallic active component catalyst and a preparation method thereof, and a method for preparing primary amines by reductive amination of biomass carbonyl compounds. Background Art

[0002] With the rapid growth of global energy demand and increasingly severe environmental problems, promoting the development of green chemical technology has become a key strategy for countries to achieve coordinated economic and ecological development. Driven by the "dual carbon" goal, the chemical industry is transforming towards high efficiency, low consumption and environmental protection, aiming to minimize dependence on petrochemical resources while reducing greenhouse gas emissions and other environmental pollution. Biomass carbonyl compounds (e.g., cyclohexanone, cyclopentanone, furfural, benzaldehyde, etc.) as an important organic intermediate can be produced by traditional petrochemical processes or by pyrolysis and hydrogenation of renewable resources such as lignin and other biomass. This biomass resource-based carbonyl compound preparation route has the characteristics of renewable resources and environmentally friendly processes, meets the requirements of green chemistry and sustainable development, and provides possibilities for the development of green carbon-based chemicals in the future.

[0003] Biomass carbonyl compounds can be converted into high-value-added primary amine products through reductive amination, which are widely used in fine chemicals, functional materials, medicines and agricultural chemicals. The synthesis process of primary amines has strict requirements on production efficiency, resource utilization and environmental impact. Among them, reductive amination is favored because of its high atomic utilization, low raw material cost and few reaction by-products. This reaction usually uses ammonia (NH) as a nitrogen source and hydrogen (H) as a reducing agent to convert biomass-based carbonyl compounds into target amine products under the action of a catalyst. This method is not only simple in process, but also can effectively reduce energy consumption and environmental pollution. At present, scientists have developed a variety of catalysts, especially supported metal catalysts, for the preparation of primary amines by reductive amination of biomass carbonyl compounds. For example, Gao et al. used a layered boron nitride-supported ruthenium catalyst to simply control the product selectivity of the reductive amination reaction of cyclohexanone in Gao M, Jia X, Ma J, et al. Self-regulated catalysis for the selective synthesis of primary amines from carbonyl compounds [J]. Green Chemistry, 2021, 23 (18): 7115-7121, anchoring ruthenium on the edge surface of layered boron nitride. The Ru / BN-e catalyst they designed reacted for 5 hours at 90 ° C, 1 MPa H2, and methanol as a solvent. The yield of the target product cyclohexylamine was 89.0%, and the product formation rate was 29.7 h -1 However, the current reductive amination of carbonyl compounds still faces some problems, such as harsh reaction conditions, low catalyst activity, the selectivity of the target product cyclohexylamine needs to be improved, and the catalyst has poor stability, which limits its large-scale application in industry. Therefore, the development of a catalyst with high activity, good selectivity, stable structure and environmental friendliness has become a research focus. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a layered nickel-aluminum bimetallic oxide-loaded bimetallic active component catalyst with high activity, selectivity and high stability, and a preparation method thereof, and a method for preparing primary amines by reductive amination of biomass carbonyl compounds. The preparation method of primary amines has a simple reaction system, mild conditions, no pollution to the environment, high efficiency and energy saving, low cost, few by-products, high yield and selectivity, and can achieve a green closed loop from raw materials to products.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A layered nickel-aluminum bimetallic oxide-supported bimetallic active component catalyst, expressed as MNi@NiAlO-T, wherein M is a noble metal, NiAlO represents a layered bimetallic oxide of Ni and Al, and T represents a calcination temperature;

[0007] The precious metal includes any one of palladium, ruthenium, platinum, rhodium and gold;

[0008] The calcination temperature is 400-700°C;

[0009] The mass proportion of the noble metal M in the catalyst is 0.5-8wt%.

[0010] The present invention also protects a method for preparing the layered nickel-aluminum bimetallic oxide-supported bimetallic active component catalyst as described above, comprising the following steps:

[0011] Step 1: ultrasonically disperse nickel nitrate hexahydrate, aluminum nitrate nonahydrate, and urea in a molar ratio of (1-4):1:(3-33) and vigorously stir until fully dissolved in water, and seal the solution in a hydrothermal kettle and crystallize at 80-120°C for 12-36 hours. After the crystallization is completed, filter and wash with a large amount of deionized water until neutral and dry, and finally grind in an agate mortar to obtain a layered nickel aluminum double hydroxide precursor, represented as NiAl-LDHs;

[0012] Step 2: Ultrasonically disperse the layered nickel aluminum double hydroxide precursor in water, add the M metal source aqueous solution drop by drop under stirring, stir and evaporate the mixed system at 70-90°C, place it in a tubular furnace with nitrogen and hydrogen mixed gas at 400-700°C for 1-2h to obtain a layered nickel aluminum bimetallic oxide-loaded bimetallic active component catalyst with a metal M element mass ratio of 0.5-8wt%, expressed as MNi@NiAlO-T.

[0013] Preferably, the ultrasonic dispersion in step 1 is 160-200W power ultrasonic dispersion for 30 minutes;

[0014] The vigorous stirring described in step 1 is vigorous stirring at a speed of 300-500 rpm for 30 minutes.

[0015] Preferably, the drying in step 1 is carried out in an oven at 60 to 80° C. for 8 to 14 hours.

[0016] Preferably, the M metal source described in step 2 is any one of palladium chloride, palladium nitrate dihydrate, potassium tetrachloropalladate, potassium chloroplatinate, ruthenium trichloride, rhodium trichloride trihydrate, and chloroauric acid trihydrate.

[0017] Preferably, the volume proportion of hydrogen in the nitrogen-hydrogen mixed gas in step 2 is 2-10%.

[0018] The present invention also protects a method for preparing primary amines by reductive amination of biomass carbonyl compounds, using the layered nickel-aluminum bimetallic oxide as described above to support a bimetallic active component catalyst.

[0019] Preferably, the method comprises the following steps:

[0020] Step 1: Use a Schlenk glass tube or a stainless steel high-temperature reactor as a reaction vessel, and add 0.5-7 mmol of biomass carbonyl compound, 10 mg of catalyst, 0.1-4 mL of ammonia water to 5-10 mL of solvent, and add 0.5-5 mmol of toluene as an internal standard, and seal the reaction vessel, wherein the mass concentration of ammonia water is 28%;

[0021] The biomass carbonyl compound includes any one of cyclohexanone, cyclopentanone, furfural, 5-methylfurfural and benzaldehyde;

[0022] Step 2: Fill the Schlenk glass tube or reactor with hydrogen and pressurize it to 0.1-3 MPa, react at 40-130° C. for 0.1-6 h, cool to room temperature, and use a needle-type organic filter for solid-liquid separation to obtain the target product, primary amine.

[0023] Preferably, the solvent includes any one of methanol, ethanol, n-propanol, isopropanol, dioxane, water, n-hexane, tetrahydrofuran, cyclohexane, isopropanol, ethyl acetate, and γ-valerolactone.

[0024] Preferably, in the step 2, high-purity hydrogen is introduced into the sealed Schlenk glass tube or reactor to replace the air therein 10 to 15 times and then filled with hydrogen to the target pressure.

[0025] Compared with the prior art, the present invention has the following technical effects:

[0026] The layered nickel-aluminum bimetallic oxide catalyst MNi@NiAlO-T loaded with bimetallic active components of the present invention is obtained by high-temperature calcination and reduction of a layered nickel-aluminum bimetallic hydroxide impregnated with a precious metal M in a tubular furnace passing a N2 / H2 mixed gas. The unique lattice confinement effect in the NiAl-LDHs precursor gives the bimetallic catalyst high particle dispersion and excellent structural stability. The catalyst retains the unique flaky structure of the layered bimetallic hydroxide before calcination and reduction, so that it has the characteristics of high specific surface area; the bimetallic catalyst has a unique surface microenvironment effect, the bimetallic active components are highly dispersed and uniform in composition, the carrier surface has an appropriate concentration of acid sites, and the synergistic effect between the highly dispersed precious metal and the partially reduced Ni in the precursor improves the catalytic activity and selectivity of the reduction amination reaction of biomass carbonyl compounds, so that it exhibits a catalytic performance that is better than that of the corresponding single metal catalyst;

[0027] The catalyst of the present invention has low preparation cost, high catalytic reduction amination activity, good selectivity, high stability, green and environmentally friendly catalytic system and is pollution-free, and is suitable for the industrial production of primary amines.

[0028] The method comprises adding a biomass carbonyl compound, ammonia water, a catalyst and a solvent into a Schlenk glass tube or a 15 mL stainless steel high temperature reactor, and performing a reduction amination reaction under a hydrogen atmosphere to obtain a target product, a primary amine. The method has the advantages of a simple reaction system, mild conditions, no pollution to the environment, high efficiency and energy saving, low cost, few by-products, high yield and high selectivity, and the like. The method can realize a green closed loop from raw materials to products by optimizing the catalyst formula and the process conditions of the reduction amination reaction of the biomass carbonyl compound and combining the utilization of renewable biomass carbonyl compound raw materials, which not only provides a technical guarantee for the efficient production of primary amines, but also injects new vitality into the development of green chemicals and lays a foundation for building a low-carbon circular economic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The diagram is a pathway diagram of the preparation of cyclohexylamine by reductive amination of cyclohexanone and the side reactions involved in Examples 7 to 17 of the present invention;

[0030] Figure 2 XRD patterns of NiAl-LDHs precursor and PdNi@NiAlO-550 catalyst in Example 2;

[0031] Figure 3 This is a scanning electron microscope photo of Pd@Ni2Al-LDHs before calcination in Example 2;

[0032] Figure 4 This is a transmission electron microscope photograph of the PdNi@NiAlO-550 catalyst in Example 2. DETAILED DESCRIPTION

[0033] The specific contents of the present invention are further explained in detail below in conjunction with embodiments.

[0034] Embodiment 1:

[0035] This embodiment provides a method for preparing a layered nickel-aluminum bimetallic oxide-supported bimetallic active component catalyst, comprising the following steps:

[0036] Step 1: 1.745 g of Ni(NO3)2·6H2O, 1.125 g of Al(NO3)3·9H2O and 1.802 g of urea were weighed in a molar ratio of 2:1:10, and the mixture was ultrasonically dispersed at 200 W for 30 min and stirred vigorously at 500 rpm for 30 min, and then fully dissolved in 60 mL of deionized water. The polytetrafluoroethylene liner containing the mixed solution was then transferred to a hydrothermal kettle, sealed and placed in an oven at 110°C for 24 h for crystallization. After the crystallization was completed, the mixture was filtered and washed with a large amount of deionized water until neutral and dried at 60°C for 14 h. Finally, the mixture was ground in an agate mortar to obtain Ni2Al-LDHs.

[0037] Step 2: Weigh 200 mg of the Ni2Al-LDHs precursor prepared in step 1 and add it to a round-bottom flask containing 10 mL of deionized water, perform ultrasonic dispersion at 160 W for 30 min, and stir vigorously at 300 rpm for 30 min. Add 10 mL of deionized water dissolved with 3.1 mg of K2PdCl4 powder dropwise under stirring, raise the temperature to 90 ° C and continue stirring until the aqueous solution in the bottle is completely evaporated. The obtained sample is reduced at high temperature in a tubular furnace with a N2:H2 mixed gas with a volume ratio of 9:1. The calcination temperature is 450 ° C, the temperature is kept for 1 h, and the heating rate is 5 ° C / min to obtain a layered nickel-aluminum bimetallic oxide-loaded bimetallic active component catalyst with a mass percentage of the precious metal M element of 0.5 wt%, expressed as PdNi@NiAlO-450.

[0038] Embodiment 2:

[0039] Example 2 is substantially the same as Example 1, except that the calcination temperature is 550° C., and the product is denoted as PdNi@NiAlO-550.

[0040] Figure 2 The XRD patterns of the Ni2Al-LDHs precursor and the PdNi@NiAlO-550 catalyst in Example 2. The Ni2Al-LDHs precursor exhibits characteristic diffraction peaks of the layered LDHs structure. The characteristic diffraction peaks of LDHs disappear in the PdNi@NiAlO catalyst obtained by high-temperature reduction, confirming the collapse of the two-dimensional layered structure of LDHs. At the same time, the diffraction peak of NiO(111) appears at 37°, while the NiO(200) and (220) planes exhibit weaker broad diffraction peaks. The results show that the LDHs precursor forms a weakly crystalline mixed oxide Ni(Al)O phase after high-temperature reduction, and the three diffraction peaks with higher intensity observed at 44.3°, 51.6° and 76.1° correspond to the characteristic diffraction peaks of NiO metal (111), (200) and (220), respectively. It is worth noting that no characteristic peaks of Pd metal were detected in the XRD spectrum. This is because the Pd metal is highly dispersed on the carrier surface and has a small lattice size.

[0041] Figure 3 This is the SEM spectrum of Pd@Ni2Al-LDHs before calcination in Example 2. From the figure, it can be seen that the synthesized LDHs samples present a typical two-dimensional layered structure, which is composed of multiple small nanosheets stacked. Figure 2 The XRD characterization results show that the urea decomposition method combined with the hydrothermal method can effectively prepare the Ni2Al-LDHs precursor with high crystallinity, and the addition of Pd has no effect on the crystal structure of Ni2Al-LDHs.

[0042] Figure 4 This is a transmission electron microscope photo of the PdNi@NiAlO-550 catalyst prepared in Example 2. From the figure, it can be seen that in the prepared catalyst, the metal palladium nickel nanoparticles are evenly dispersed in the carrier without agglomeration.

[0043] Embodiment 3:

[0044] Example 3 is substantially the same as Example 1, except that the calcination temperature is 600° C., and the product is denoted as PdNi@NiAlO-600.

[0045] Embodiment 4:

[0046] This embodiment provides a method for preparing a layered nickel-aluminum bimetallic oxide-supported bimetallic active component catalyst, comprising the following steps:

[0047] Step 1: 3.49 g of Ni(NO3)2·6H2O, 1.125 g of Al(NO3)3·9H2O and 3.604 g of urea were weighed in a molar ratio of 4:1:20, and the mixture was dispersed ultrasonically at 160 W for 30 min and stirred vigorously at 300 rpm for 30 min, and then fully dissolved in 60 mL of deionized water. The polytetrafluoroethylene liner containing the mixed solution was then transferred to a hydrothermal kettle, sealed and placed in an oven at 80°C for 36 h for crystallization. After the crystallization was completed, the mixture was filtered and washed with a large amount of deionized water until neutral and dried at 80°C for 8 h. Finally, the mixture was ground in an agate mortar to obtain Ni4Al-LDHs.

[0048] Step 2: Weigh 200 mg of the Ni4Al-LDHs precursor prepared in step 1 and add it to a round-bottom flask containing 10 mL of deionized water, perform ultrasonic dispersion at 160 W for 30 min, and vigorously stir at 300 rpm for 30 min. Add 10 mL of deionized water dissolved with 10.2 mg of palladium nitrate dihydrate powder dropwise under stirring, raise the temperature to 70°C and continue stirring until the aqueous solution in the bottle is completely evaporated. The obtained sample is reduced at high temperature in a tubular furnace with a N2:H2 mixed gas with a volume ratio of 9:1. The calcination temperature is 400°C, the temperature is kept for 1 h, and the heating rate is 5°C / min to obtain a layered nickel-aluminum bimetallic oxide-loaded bimetallic active component catalyst with a mass percentage of the precious metal M element of 2 wt%.

[0049] Example 5

[0050] Step 1: 0.8725 g of Ni(NO3)2·6H2O, 1.125 g of Al(NO3)3·9H2O and 0.5406 g of urea were weighed in a molar ratio of 1:1:3, and the mixture was dispersed ultrasonically at 180 W for 30 min and stirred vigorously at 400 rpm for 30 min, and then fully dissolved in 60 mL of deionized water. The polytetrafluoroethylene liner containing the mixed solution was then transferred to a hydrothermal kettle, sealed and placed in an oven at 100°C for 24 h for crystallization. After the crystallization was completed, the mixture was filtered and washed with a large amount of deionized water until neutral and dried at 70°C for 12 h. Finally, the mixture was ground in an agate mortar to obtain NiAl-LDHs.

[0051] Step 2: Weigh 200 mg of the Ni4Al-LDHs precursor prepared in step 1 and add it to a round-bottom flask containing 10 mL of deionized water, perform ultrasonic dispersion at 160 W for 30 min, and vigorously stir at 300 rpm for 30 min. Add 10 mL of deionized water dissolved with 21.6 mg of ruthenium trichloride powder dropwise under stirring, raise the temperature to 80 ° C and continue stirring until the aqueous solution in the bottle is completely evaporated. The obtained sample is reduced at high temperature in a tubular furnace with a N2:H2 mixed gas with a volume ratio of 9:1. The calcination temperature is 700 ° C, the temperature is kept for 1.5 h, and the heating rate is 5 ° C / min to obtain a layered nickel-aluminum bimetallic oxide-loaded bimetallic active component catalyst with a mass percentage of the precious metal M element of 5 wt%.

[0052] Example 6

[0053] Step 1: 2.6175 g of Ni(NO3)2·6H2O, 1.125 g of Al(NO3)3·9H2O and 5.9466 g of urea were weighed in a molar ratio of 3:1:33, and the mixture was dispersed ultrasonically at 200 W for 30 min and stirred vigorously at 500 rpm for 30 min, and then fully dissolved in 60 mL of deionized water. The polytetrafluoroethylene liner containing the mixed solution was then transferred to a hydrothermal kettle, sealed and placed in an oven at 110°C for 24 h for crystallization. After the crystallization was completed, the mixture was filtered and washed with a large amount of deionized water until neutral and dried at 60°C for 14 h. Finally, the mixture was ground in an agate mortar to obtain Ni2Al-LDHs.

[0054] Step 2: Weigh 200 mg of the Ni2Al-LDHs precursor prepared in step 1 and add it to a round-bottom flask containing 10 mL of deionized water, perform ultrasonic dispersion at 160 W for 30 min, and stir vigorously at 300 rpm for 30 min. Add 10 mL of deionized water dissolved with 34.8 mg of tetrachloroauric acid trihydrate powder dropwise under stirring. Raise the temperature to 90°C and continue stirring until the aqueous solution in the bottle is completely evaporated. Reduce the obtained sample at high temperature in a tubular furnace with a N2:H2 mixed gas with a volume ratio of 9:1. The calcination temperature is 450°C, and the heat is maintained for 2 h. The heating rate is 5°C / min to obtain a layered nickel-aluminum bimetallic oxide-loaded bimetallic active component catalyst with a mass percentage of the precious metal M element of 8 wt%.

[0055] Example 7

[0056] This embodiment provides a method for preparing cyclohexylamine by reductive amination of biomass-based cyclohexanone, comprising the following steps, as shown in the reaction pathway diagram: Figure 1 As shown:

[0057] Step 1: Use a Schlenk glass tube or a stainless steel high-temperature reactor as a reaction vessel, and add 0.5 mmol of cyclohexanone, 10 mg of a catalyst (the catalyst in Example 1), and 0.5 mL of aqueous ammonia to 5 mL of a methanol solvent, and further add 5 mmol of toluene as an internal standard, and seal the reaction vessel, wherein the mass concentration of aqueous ammonia is 28%;

[0058] Step 2: high-purity hydrogen is introduced into a sealed Schlenk glass tube to replace the air therein 10 times, and then the hydrogen is filled and pressurized to 0.1 MPa. After reacting at 70° C. for 2.5 hours, it is cooled to room temperature and solid-liquid separation is performed using a needle organic filter to obtain the target product cyclohexylamine.

[0059] After the reaction is completed, the conversion rate of cyclohexanone and the selectivity of cyclohexylamine are calculated according to the following formula.

[0060] Example 8

[0061] Example 8 is substantially the same as Example 7, except that the catalyst is PdNi@NiAlO-550 prepared in Example 2.

[0062] Example 9

[0063] Example 9 is substantially the same as Example 7, except that the catalyst is PdNi@NiAlO-600 prepared in Example 3.

[0064] The reaction products prepared in Examples 7-9 were quantitatively analyzed by gas chromatography (Agilent 7820, Agilent Technologies, Beijing, China). The separation column was SE-54 with a specification of 30 m×0.25 mm×1.0 μm. The gas chromatography column was tested by the following method: 50°C for 2 min, heating to 250°C at a rate of 10°C / min, and then kept at 250°C for 2 min. The injection port temperature was 250°C and the detector temperature was 250°C. The results of the FID hydrogen flame ionization detector are shown in Table 1.

[0065] Table 1 Effect of catalysts calcined at different temperatures on cyclohexanone conversion and cyclohexylamine selectivity

[0066] Example catalyst Cyclohexanone conversion rate / % Cyclohexylamine selectivity / % 7 PdNi@NiAlO-450 58 20 8 PdNi@NiAlO-550 100 99 9 PdNi@NiAlO-600 90 91

[0067] It can be seen from Table 1 that when other reaction conditions remain the same, the catalyst reduced at 550°C has the best catalytic performance, ensuring that the conversion rate of cyclohexanone and the selectivity of cyclohexylamine are both the highest, while saving the high-temperature hydrogen reduction cost of catalyst preparation as much as possible.

[0068] Example 10

[0069] This embodiment provides a method for preparing cyclohexylamine by reductive amination of biomass-based cyclohexanone, comprising the following steps:

[0070] Step 1: Use a Schlenk glass tube or a stainless steel high-temperature reactor as a reaction vessel, and add 7 mmol of cyclohexanone, 10 mg of a catalyst, and 4 ml of ammonia water to 10 mL of an ethanol solvent, and further add 3 mmol of toluene as an internal standard, and seal the reaction vessel, wherein the mass concentration of the ammonia water is 28%; the catalyst is the catalyst PdNi@NiAlO-550 prepared in Example 2;

[0071] Step 2: high-purity hydrogen is introduced into a sealed Schlenk glass tube to replace the air therein 15 times, and then the hydrogen is filled and pressurized to 3 MPa. After reacting at 130° C. for 0.1 h, the tube is cooled to room temperature and solid-liquid separation is performed using a needle organic filter to obtain the target product cyclohexylamine.

[0072] Embodiment 11

[0073] This embodiment provides a method for preparing cyclohexylamine by reductive amination of biomass-based cyclohexanone, comprising the following steps:

[0074] Step 1: Use a Schlenk glass tube or a stainless steel high-temperature reactor as a reaction vessel, and add 5 mmol of cyclohexanone, 10 mg of a catalyst, and 0.1 mL of ammonia water to 8 mL of isopropanol solvent, and further add 0.5 mmol of toluene as an internal standard, and seal the reaction vessel, wherein the mass concentration of ammonia water is 28%; the catalyst is the catalyst PdNi@NiAlO-550 prepared in Example 2;

[0075] Step 2: high-purity hydrogen is introduced into a sealed Schlenk glass tube to replace the air therein 12 times, and then the hydrogen is filled and pressurized to 0.5 MPa. After reacting at 40° C. for 6 hours, it is cooled to room temperature and solid-liquid separation is performed using a needle organic filter to obtain the target product cyclohexylamine.

[0076] Example 12

[0077] This embodiment provides a method for preparing cyclohexylamine by reductive amination of biomass-based cyclohexanone, comprising the following steps:

[0078] Step 1: Use a Schlenk glass tube or a stainless steel high-temperature reactor as a reaction vessel, add 2 mmol of cyclohexanone, 10 mg of a catalyst, and 2 mL of ammonia water to 5 mL of water, respectively, and add 2 mmol of toluene as an internal standard, and seal the reaction vessel, wherein the mass concentration of the ammonia water is 28%; the catalyst is the catalyst PdNi@NiAlO-550 prepared in Example 2;

[0079] Step 2: high-purity hydrogen is introduced into a sealed Schlenk glass tube to replace the air therein 10 times, and then the hydrogen is filled and pressurized to 2 MPa. After reacting at 100° C. for 3 hours, the tube is cooled to room temperature and solid-liquid separation is performed using a needle organic filter to obtain the target product cyclohexylamine.

[0080] The catalyst PdNi@NiAlO-550 in Example 8 was recovered, washed repeatedly three times with methanol, dried in a vacuum drying oven at 60° C., and then put into use.

[0081] Embodiment 13

[0082] Example 13 is basically the same as Example 8, except that the catalyst PdNi@NiAlO-550 in Example 8 is used for one cycle.

[0083] Embodiment 14

[0084] Example 14 is basically the same as Example 8, except that the catalyst PdNi@NiAlO-550 in Example 13 is used in two cycles.

[0085] Embodiment 15

[0086] Example 15 is basically the same as Example 8, except that the catalyst PdNi@NiAlO-550 in Example 14 is used in a three-cycle manner.

[0087] Example 16

[0088] Example 16 is basically the same as Example 8, except that the catalyst PdNi@NiAlO-550 in Example 15 is used in four cycles.

[0089] Embodiment 17

[0090] Example 17 is basically the same as Example 8, except that the catalyst PdNi@NiAlO-550 in Example 16 is used in a five-cycle manner.

[0091] For the products of Examples 13-17, the clear liquid was filtered out using a needle-type organic filter and subjected to gas chromatography detection. The results are shown in Table 2:

[0092] Table 2 Conversion of cyclohexanone and selectivity of cyclohexylamine in Examples 13-17

[0093] Example Cycle times Cyclohexanone conversion rate / % Cyclohexylamine selectivity / % 13 1 100 99 14 2 100 99 15 3 100 98 16 4 100 98 17 5 99 98

[0094] Result analysis: It can be seen from Table 2 that the catalyst prepared by the present invention can better maintain its high catalytic activity in the cycle experiment.

[0095] Embodiment 18

[0096] This embodiment provides a method for preparing cyclopentylamine by reductive amination of biomass-based cyclopentanone, comprising the following steps:

[0097] Step 1: Use a Schlenk glass tube or a stainless steel high-temperature reactor as a reaction vessel, and add 0.5 mmol cyclopentanone, 10 mg catalyst, and 0.5 mL ammonia water to 5 mL methanol, and add 2 mmol toluene as an internal standard, and seal the reaction vessel, wherein the mass concentration of ammonia water is 28%; the catalyst is the catalyst PdNi@NiAlO-550 prepared in Example 2;

[0098] Step 2: High-purity hydrogen is introduced into a sealed Schlenk glass tube to replace the air therein 10 times, and then the hydrogen is filled and pressurized to 0.1 MPa. After reacting at 70° C. for 2.5 hours, the tube is cooled to room temperature and solid-liquid separation is performed using a needle-type organic filter to obtain the target product cyclopentylamine; the clear liquid is filtered out using a needle-type organic filter for gas chromatography detection, and the yield is 93%.

[0099] Embodiment 19

[0100] This embodiment provides a method for preparing furfurfural by reductive amination of biomass-based furfural, comprising the following steps:

[0101] Step 1: Use a Schlenk glass tube or a stainless steel high-temperature reactor as a reaction vessel, and add 0.5 mmol furfural, 10 mg catalyst, and 0.5 mL ammonia water to 5 mL methanol, respectively, and add 2 mmol toluene as an internal standard, and seal the reaction vessel, wherein the mass concentration of ammonia water is 28%; the catalyst is the catalyst PdNi@NiAlO-550 prepared in Example 2;

[0102] Step 2: high-purity hydrogen is introduced into a sealed Schlenk glass tube to replace the air therein 10 times, and then the hydrogen is filled and pressurized to 0.4 MPa. After reacting at 90° C. for 2.5 hours, the tube is cooled to room temperature and solid-liquid separation is performed using a needle-type organic filter to obtain the target product furfurylamine; the clear liquid is filtered out using a needle-type organic filter for gas chromatography detection, and the yield is 85%.

[0103] Embodiment 20

[0104] This embodiment provides a method for preparing 5-methylfurfurylamine by reductive amination of biomass-based 5-methylfurfural, comprising the following steps:

[0105] Step 1: Use a Schlenk glass tube or a stainless steel high-temperature reactor as a reaction vessel, and add 0.5 mmol 5-methylfurfural, 10 mg catalyst, and 0.5 mL ammonia water to 5 mL methanol, and further add 5 mmol toluene as an internal standard, and seal the reaction vessel, wherein the mass concentration of ammonia water is 28%; the catalyst is the catalyst PdNi@NiAlO-550 prepared in Example 2;

[0106] Step 2: High-purity hydrogen is introduced into a sealed Schlenk glass tube to replace the air therein once, and then the hydrogen is filled and pressurized to 0.1 MPa. After reacting at 70° C. for 2.5 hours, the tube is cooled to room temperature and solid-liquid separation is performed using a needle-type organic filter to obtain the target product 5-methylfurfurylamine; the clear liquid is filtered out using a needle-type organic filter for gas chromatography detection, and the yield is 84%.

[0107] Embodiment 21

[0108] This embodiment provides a method for preparing benzylamine by reductive amination of biomass-based benzaldehyde, comprising the following steps:

[0109] Step 1: Use a Schlenk glass tube or a stainless steel high-temperature reactor as a reaction vessel, and add 0.5 mmol of benzaldehyde, 10 mg of catalyst, and 0.5 mL of ammonia water to 5 mL of methanol, and further add 0.5 mmol of toluene as an internal standard, and seal the reaction vessel, wherein the mass concentration of ammonia water is 28%; the catalyst is the catalyst PdNi@NiAlO-550 prepared in Example 2;

[0110] Step 2: High-purity hydrogen is introduced into a sealed Schlenk glass tube to replace the air therein 15 times, and then the hydrogen is filled and pressurized to 0.1 MPa. After reacting at 70° C. for 2.5 hours, the tube is cooled to room temperature and solid-liquid separation is performed using a needle-type organic filter to obtain the target product, benzylamine; the clear liquid is filtered out using a needle-type organic filter for gas chromatography detection, and the yield is 91%.

[0111] In summary, the layered nickel-aluminum bimetallic oxide-loaded bimetallic active component catalyst prepared by the present invention exhibits excellent catalytic performance in the reductive amination reaction of biomass carbonyl compounds (containing C=O groups) including cyclohexanone, cyclopentanone, furfural, 5-methylfurfural and benzaldehyde to synthesize primary amines, and has good industrial application prospects.

[0112] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The present invention adopts MNi@NiAlO-T catalyst, M is any one of palladium, ruthenium, platinum, rhodium, and gold, and the solvent is any one of methanol, ethanol, n-propanol, isopropanol, dioxane, water, n-hexane, tetrahydrofuran, cyclohexane, isopropanol, ethyl acetate, and γ-valerolactone, which can realize the efficient and highly selective reduction amination of biomass carbonyl compounds to synthesize primary amine chemicals. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A layered nickel-aluminum bimetallic oxide-supported bimetallic active component catalyst, characterized in that: The expression is MNi@NiAlO-T, where M is a noble metal, NiAlO represents a layered bimetallic oxide of Ni and Al, and T represents the calcination temperature; The precious metal includes any one of palladium, ruthenium, platinum, rhodium and gold; The calcination temperature is 400-700°C; The mass proportion of the noble metal M in the catalyst is 0.5-8wt%.

2. A method for preparing a layered nickel-aluminum bimetallic oxide-supported bimetallic active component catalyst as claimed in claim 1, characterized in that: The following steps are involved: Step 1: ultrasonically disperse nickel nitrate hexahydrate, aluminum nitrate nonahydrate, and urea in a molar ratio of (1-4):1:(3-33) and vigorously stir until fully dissolved in water, and seal the solution in a hydrothermal kettle and crystallize at 80-120°C for 12-36 hours. After the crystallization is completed, filter and wash with a large amount of deionized water until neutral and dry, and finally grind in an agate mortar to obtain a layered nickel aluminum double hydroxide precursor, represented as NiAl-LDHs; Step 2: Ultrasonically disperse the layered nickel aluminum double hydroxide precursor in water, add the M metal source aqueous solution drop by drop, stir and evaporate the mixed system at 70-90°C, and place it in a tubular furnace with nitrogen and hydrogen mixed gas for high temperature reduction at 400-700°C for 1-2h to obtain a layered nickel aluminum bimetallic oxide-loaded bimetallic active component catalyst with a metal M element mass proportion of 0.5-8wt%, expressed as MNi@NiAlO-T.

3. The method for preparing the layered nickel-aluminum bimetallic oxide-supported bimetallic active component catalyst according to claim 2, characterized in that: The ultrasonic dispersion described in step 1 is 160-200W power ultrasonic dispersion for 30 minutes; The vigorous stirring described in step 1 is vigorous stirring at a speed of 300-500 rpm for 30 minutes.

4. The method for preparing the layered nickel-aluminum bimetallic oxide-supported bimetallic active component catalyst according to claim 2, characterized in that: The drying described in step 1 is drying in an oven at 60 to 80° C. for 8 to 14 hours.

5. The method for preparing the layered nickel-aluminum bimetallic oxide-supported bimetallic active component catalyst according to claim 2, characterized in that: The M metal source described in step 2 is any one of palladium chloride, palladium nitrate dihydrate, potassium tetrachloropalladate, potassium chloroplatinate, ruthenium trichloride, rhodium trichloride trihydrate, and chloroauric acid trihydrate.

6. The method for preparing the layered nickel-aluminum bimetallic oxide-supported bimetallic active component catalyst according to claim 2, characterized in that: The volume proportion of hydrogen in the nitrogen-hydrogen mixed gas described in step 2 is 2-10%.

7. A method for preparing primary amines by reductive amination of biomass carbonyl compounds, characterized in that: The layered nickel-aluminum bimetallic oxide as claimed in claim 1 is used to support a bimetallic active component catalyst.

8. The method for preparing primary amines by reductive amination of biomass carbonyl compounds according to claim 7, characterized in that: The following steps are involved: Step 1: Use a Schlenk glass tube or a stainless steel high-temperature reactor as a reaction vessel, and add 0.5-7 mmol of biomass carbonyl compound, 10 mg of catalyst, 0.1-4 mL of ammonia water to 5-10 mL of solvent, and add 0.5-5 mmol of toluene as an internal standard, and seal the reaction vessel, wherein the mass concentration of ammonia water is 28%; The biomass carbonyl compound includes any one of cyclohexanone, cyclopentanone, furfural, 5-methylfurfural and benzaldehyde; Step 2: Fill the Schlenk glass tube or reactor with hydrogen and pressurize it to 0.1-3 MPa, react at 40-130° C. for 0.1-6 h, cool to room temperature, and use a needle-type organic filter for solid-liquid separation to obtain the target product cyclohexylamine.

9. The method for preparing primary amines by reductive amination of biomass carbonyl compounds according to claim 8, characterized in that: The solvent includes any one of methanol, ethanol, n-propanol, isopropanol, dioxane, water, n-hexane, tetrahydrofuran, cyclohexane, isopropanol, ethyl acetate, and γ-valerolactone.

10. The method for preparing primary amines by reductive amination of biomass carbonyl compounds according to claim 8, characterized in that: In the step 2, high-purity hydrogen is introduced into the sealed Schlenk glass tube or reactor to replace the air therein 10 to 15 times, and then hydrogen is filled to the target pressure.

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