A hydrogenation catalyst and its preparation method and application

Abstract

The present invention provides a hydrogenation catalyst, its preparation method, and application, belonging to the field of catalyst technology. The catalyst uses mesoporous CaO-ZrO2 as a carrier; nickel, cobalt, and copper as active components, wherein the molar ratio of nickel, cobalt, and copper is 5-10:1-3:1, and the dispersion of the active components is 70-86%. The hydrogenation catalyst provided by the present invention has good activity, a long service life, and high product selectivity, effectively reducing catalyst consumption during the production process, thereby lowering production costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst preparation, and in particular relates to a hydrogenation catalyst and a preparation method and application thereof. Background Art

[0002] Meta-xylylenediamine (MXDA) is a colorless, transparent liquid, an aliphatic amine with an aromatic ring, soluble in water and organic solvents. It is mainly used as an epoxy resin curing agent and a polymerization monomer for nylon MXD6. It is an important fine chemical intermediate that is currently in urgent need of development in China.

[0003] There are generally two synthetic routes for the preparation of MXDA: one uses m-xylene as the starting material, through bromination and amination to produce MXDA. This method is gradually being phased out due to high production costs, a long synthesis process, and significant environmental pollution. The other uses m-xylene as the starting material, through gas-phase ammoxidation to produce isophthalonitrile (IPN), which is then catalytically hydrogenated to produce MXDA. Currently, the second synthetic route is the predominant method for industrial production of MXDA. The technology for the first step, m-xylene ammoxidation to produce IPN, is mature. The second step, catalytic hydrogenation of IPN to MXDA, can be performed using either batch hydrogenation in an autoclave or continuous fixed-bed hydrogenation process. Catalysts used for the catalytic hydrogenation of IPN to produce MXDA primarily include Raney nickel, supported nickel, supported cobalt, and supported ruthenium. Raney nickel is simple to prepare, inexpensive, and highly active, but the catalyst requires large amounts and is prone to pulverization and deactivation, making it non-reusable. Supported cobalt or ruthenium catalysts are relatively expensive, while supported nickel catalysts generally have low hydrogenation activity. Therefore, developing a highly active and stable catalyst is crucial. Summary of the Invention

[0004] In view of this, the present invention provides a hydrogenation catalyst and a preparation method and application thereof. The hydrogenation catalyst provided by the present invention has good catalytic activity, long service life, and high product selectivity.

[0005] In order to achieve the above object, the present invention provides a hydrogenation catalyst, which uses mesoporous CaO-ZrO2 as a carrier; Ni, Co, and Cu as active components, wherein the element molar ratio of Ni, Co, and Cu is 5-10:1-3:1, and the dispersion of the active components is 70-86%.

[0006] Preferably, the active component accounts for 30% to 45% of the total weight of the catalyst, calculated as metal elements.

[0007] Preferably, the mesoporous CaO-ZrO2 is prepared by the following method:

[0008] 1) adding an alcohol solution of zirconium n-propoxide and acetylacetone to an alcohol solution of calcium nitrate and Pluronic P123 under stirring to obtain a mixed solution;

[0009] 2) adjusting the pH of the mixed solution to 5-6 and then aging it to obtain a gel;

[0010] 4) refluxing the gel in an alkaline solution, and washing the gel after the reflux to obtain a solid material;

[0011] 5) calcining the solid material to obtain mesoporous CaO-ZrO2.

[0012] Preferably, the aging temperature in step 2) is 45-80° C., and the aging time is 6-48 hours.

[0013] Preferably, drying and grinding are sequentially performed before calcination in step 5); the drying temperature is 60-120° C. and the drying time is 12-24 hours.

[0014] The present invention provides a method for preparing any one of the above-mentioned hydrogenation catalysts, comprising the following steps:

[0015] a. The mesoporous CaO-ZrO2 was added to a precursor solution containing Ni, Co, and Cu, and ultrasonicated, allowed to stand, and dried to obtain a catalyst precursor;

[0016] b. calcining the catalyst precursor to obtain a calcined solid;

[0017] c. reducing the calcined solid to obtain a hydrogenation catalyst.

[0018] Preferably, after the reduction in step c, a gas phase passivation method is further used for passivation treatment, and the specific operation is: an inert gas containing 0.5-3% by mass of oxygen is introduced for passivation.

[0019] Preferably, in step a, standing and drying are carried out in a vacuum environment; the standing time is 12 to 48 hours; the drying temperature is 70 to 85° C., and the drying time is 12 to 24 hours.

[0020] Preferably, the calcination temperature in step b is 200-800° C. and the calcination time is 5-8 hours.

[0021] The present invention provides use of any one of the above hydrogenation catalysts in the preparation of m-xylylenediamine.

[0022] Compared with the prior art, the advantages and positive effects of the present invention are:

[0023] The catalyst provided by the present invention uses alkaline mesoporous CaO-ZrO2 as a carrier, reduces the generation of by-products, and improves the selectivity of MXDA. The addition of Cu can effectively improve the dispersion of Ni and Co, effectively improve the utilization rate of metals, reduce the amount of metal used, and reduce the cost of catalyst production. Moreover, the highly dispersed supported metal catalyst not only has good activity, selectivity, and stability, but also often has strong resistance to carbon deposition and metal sintering. Ni-based catalysts have good catalytic activity and are low in price, and are therefore widely used in industrial production. However, this catalyst has serious carbon deposition and is prone to sintering, while Co-based catalysts have good catalytic activity and resistance to carbon deposition and sintering, but are relatively expensive. The synergistic effect of the two active components, Ni and Co, can effectively improve the stability of the catalyst. Using Ni, Co, and Cu as active components, the three metals work synergistically to improve the activity, selectivity, and stability of the metal. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the N2- adsorption-desorption curve of the catalyst prepared in Example 2;

[0025] Figure 2 This is the scanning electron microscope mapping image of the catalyst prepared in Example 2. DETAILED DESCRIPTION

[0026] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0027] The invention provides a hydrogenation catalyst. The catalyst uses mesoporous CaO-ZrO2 as a carrier; Ni, Co and Cu as active components, wherein the element molar ratio of Ni, Co and Cu is 5-10:1-3:1, and the dispersion degree of the active components is 70-86%.

[0028] The hydrogenation catalyst provided by the present invention uses mesoporous CaO-ZrO2 as a carrier. In the present invention, the mesoporous CaO-ZrO2 is preferably prepared by the following method:

[0029] 1) adding an alcohol solution of zirconium n-propoxide and acetylacetone to an alcohol solution of calcium nitrate and Pluronic P123 under stirring to obtain a mixed solution;

[0030] 2) adjusting the pH of the mixed solution to 5-6 and then aging it to obtain a gel;

[0031] 4) refluxing the gel in an alkaline solution, and washing the gel after the reflux to obtain a solid material;

[0032] 5) calcining the solid material to obtain mesoporous CaO-ZrO2.

[0033] In the present invention, an alcoholic solution of zirconium n-propoxide and acetylacetone is added to an alcoholic solution of calcium nitrate and Pluronic P123 under stirring to produce a mixed solution. In the present invention, the mass ratio of the zirconium n-propoxide to acetylacetone is preferably 80:8-10. In the present invention, the mass ratio of the calcium nitrate to Pluronic P123 is preferably 20-40:20.

[0034] After obtaining the mixed solution, the present invention adjusts the pH of the mixed solution to 5-6 and then ages it to obtain a gel. In the present invention, the temperature during the aging is preferably 45-80° C., and the aging time is preferably 6-48 hours.

[0035] After obtaining the gel, the present invention refluxes the gel in an alkaline solution and then washes it to obtain a solid material. In the present invention, the alkaline solution is preferably NaOH, KOH, ammonia water, Na2CO3, or NaHCO3; the concentration of the alkaline solution is preferably 0.2 to 5 mol / L. In the present invention, the reflux time is preferably 20 to 24 hours. In the present invention, deionized water at a volume 2 to 5 times the mass of the solid is preferably used for washing to remove excess metal. During the washing process, the conductivity is preferably measured using a conductivity meter to maintain a constant value of 0 to 1.0 mS / cm.

[0036] After obtaining the solid material, the present invention calcines the solid material to obtain mesoporous CaO-ZrO2. In the present invention, drying and grinding are preferably performed sequentially before calcination; the drying temperature is preferably 60-120°C, and the drying time is preferably 12-24 hours. Grinding into powder in the present invention facilitates sufficient calcination and increases the specific surface area of ​​the catalyst. In the present invention, the calcination temperature is preferably 200-800°C, more preferably 400-600°C; and the calcination time is preferably 3-12 hours, more preferably 5-8 hours.

[0037] In the present invention, a mesoporous CaO-ZrO2 carrier is prepared by a gel-sol method using Pluronic P123 as a template. P123 is an important non-ionic surfactant, and the synthesized nanomaterial has the advantages of high specific surface area, small grain size and uniform pore size. In the prior art, aluminum oxide and / or silicon oxide are commonly used as carriers for loading nickel. However, aluminum oxide and silicon oxide have a certain surface acidity. When catalyzing, the surface acidity of the catalyst easily leads to an increase in by-products during the hydrogenation process, thereby reducing selectivity. The mesoporous CaO-ZrO2 carrier provided by the present invention has acid-base dual functionality, which can effectively regulate the acid-base active sites of the catalyst, reduce by-products, improve selectivity, and ensure that the catalyst has high catalytic activity.

[0038] The hydrogenation catalyst provided by the present invention comprises Ni, Co, and Cu as active components, wherein the molar ratio of Ni, Co, and Cu is 5-10:1-3:1, and the dispersion of the active components is 70-86%. In the present invention, preferably, the active components, calculated as metal elements, constitute 30% to 45% of the total weight of the catalyst. In the present invention, the addition of Cu effectively improves the dispersion of Ni and Co, effectively increasing metal utilization, reducing metal usage, and lowering catalyst production costs. Furthermore, highly dispersed supported metal catalysts not only exhibit excellent activity, selectivity, and stability, but also often exhibit strong resistance to carbon deposition and metal sintering. Ni-based catalysts have high catalytic activity and are inexpensive, making them widely used in industrial production. However, these catalysts suffer from severe carbon deposition and are prone to sintering. Co-based catalysts have good catalytic activity and resistance to carbon deposition and sintering, but are relatively expensive. The synergistic effect of the two active components, Ni and Co, can effectively improve the stability of the catalyst. The three components work together to improve the dispersion and catalytic activity of the metals.

[0039] The present invention provides a method for preparing any one of the above-mentioned hydrogenation catalysts, comprising the following steps:

[0040] a. The mesoporous CaO-ZrO2 was added to a precursor solution containing Ni, Co, and Cu, and ultrasonicated, allowed to stand, and dried to obtain a catalyst precursor;

[0041] b. calcining the catalyst precursor to obtain a calcined solid;

[0042] c. reducing the calcined solid to obtain a hydrogenation catalyst.

[0043] The present invention adds mesoporous CaO-ZrO2 to a precursor solution containing Ni, Co, and Cu, and sequentially performs sonication, standing, and drying to obtain a catalyst precursor. In the present invention, the precursor of Ni is preferably nickel sulfate, nickel chloride, nickel nitrate, nickel acetate, nickel sulfamate, nickel bromide, nickelous hydroxide, or nickel carbonyl; the precursor of Co is preferably cobalt sulfate, cobalt chloride, cobalt bromide, cobalt nitrate, cobalt stearate, cobalt decanoate, cobalt naphthenate, or cobalt boroacylate; the precursor of Cu is preferably copper sulfate, cuprous sulfate, cuprous chloride, or copper nitrate. In the present invention, standing and drying are preferably performed in a vacuum environment; the standing time is preferably 12 to 48 hours, more preferably 24 to 36 hours; the drying temperature is preferably 70 to 85°C, and the drying time is preferably 12 to 24 hours.

[0044] After obtaining the catalyst precursor, the present invention calcines the catalyst precursor to obtain a calcined solid. In the present invention, the calcination temperature is preferably 200-800° C., more preferably 400-500° C., and the calcination time is preferably 5-8 hours.

[0045] After obtaining the calcined solid, the present invention reduces the calcined solid to obtain a hydrogenation catalyst. In the present invention, the reduction method is preferably to reduce the calcined solid using a hydrogen-argon mixed gas containing 5-20 vol% hydrogen for 2-15 hours.

[0046] After reduction, the present invention preferably also employs a gas-phase passivation method for passivation. Specifically, the passivation is performed by introducing an inert gas containing 0.5-3% oxygen by mass. In the present invention, the inert gas is preferably nitrogen, helium, or argon. In the present invention, using oxygen as the passivating agent and the inert gas as the diluent for passivation can improve catalyst stability.

[0047] The present invention provides the use of any of the above-mentioned hydrogenation catalysts in the preparation of meta-xylylenediamine. In the present invention, the method for preparing meta-xylylenediamine preferably comprises: introducing isophthalonitrile, a catalyst, and a methanol-toluene solvent into a reactor, replacing them with nitrogen and hydrogen respectively, and then introducing hydrogen to carry out the reaction. In the present invention, the concentration of isophthalonitrile in the solvent is preferably 0.128 to 0.256 g / mL, more preferably 0.128 g / mL; the mass ratio of the catalyst to isophthalonitrile is preferably 0.05:1 to 0.3:1, more preferably 0.1:1; the reaction temperature is preferably 20 to 200°C, more preferably 50 to 150°C, and most preferably 60 to 120°C; the pressure during the reaction is preferably 0.1 to 15 MPa, more preferably 2 to 10 MPa, and most preferably 3 to 5 MPa.

[0048] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0049] Example 1

[0050] 20 g of Pluronic P123 and 30.6 g of Ca(NO3)2·4H2O were dissolved in 500 mL of anhydrous ethanol, which was recorded as solution A. 80 g of zirconium n-propoxide (Zr(OPr)4) (60 wt.% n-propanol, Aladdin) and 8.7 g of acetylacetone were dissolved in 320 mL of anhydrous ethanol, which was recorded as solution B.

[0051] A mixed solution of solution B and 32 mL of water was slowly added dropwise to solution A under vigorous stirring, the pH was adjusted to 5, and the solution was aged at 60 ° C for 24 h. The resulting sol was then refluxed in a 1 mol / L NaOH solution for 24 h. Subsequently, excess Na ions were removed with deionized water and dried at 80 ° C overnight. The solid powder was then ground into a muffle furnace and heated to 580 ° C at a rate of 10 ° C / min and maintained for 8 h to obtain CaO-ZrO2 (n Ca / n Zr =1:2).

[0052] Example 2

[0053] Ni(NO3)2·6H2O, Co(NO3)2·6H2O and Cu(NO3)2·3H2O were dissolved in deionized water in a molar ratio of 10:2:1 to form a solution, and stirred at room temperature for half an hour. Then, the CaO-ZrO2 prepared in Example 1 was added to the precursor solution at an active component loading of 40wt%, and continuously stirred and ultrasonicated for half an hour to form a mixture, which was allowed to stand in a vacuum oven for 24 hours. After standing, the mixture was placed in an 80°C vacuum drying oven and dried for 12 hours. The dried mixture was placed in a muffle furnace and heated to 550°C at a heating rate of 8°C / min and calcined for 10 hours. Then, a 10vol% H / Ar mixed gas was introduced into the tubular furnace (the flow rate of the mixed gas was 200ml / min, which was always introduced during the reduction process), and the temperature was raised to 400°C at 5°C / min, maintained for 5 hours, and the catalyst was reduced to obtain a catalyst marked as Ni 10 Co2Cu1 / CaO-ZrO2. The dispersion of the active components in the catalyst was 73%, as measured and calculated using a chemical adsorption instrument. Figure 1 The N2-adsorption-desorption curve of the catalyst shows that the catalyst is a mesoporous material, and the specific surface area of ​​the catalyst is 86.4 m 2 / g. Figure 2 This is the scanning electron microscope mapping image of the catalyst prepared in Example 2.

[0054] Example 3

[0055] Ni(NO3)2·6H2O, Co(NO3)2·6H2O and Cu(NO3)2·3H2O were dissolved in deionized water in a molar ratio of 10:1:1 to form a solution, and stirred at room temperature for half an hour. Then, the CaO-ZrO2 prepared in Example 1 was added to the precursor solution at an active component loading of 40wt%, and continuously stirred and ultrasonicated for half an hour to form a mixture, which was allowed to stand in a vacuum oven for 36 hours. After standing, the mixture was placed in an 80°C vacuum drying oven and dried for 12 hours. The dried mixture was placed in a muffle furnace and heated to 300°C at a heating rate of 8°C / min and calcined for 5 hours. Then, 15vol% H / Ar mixed gas was introduced into the tubular furnace (the flow rate of the mixed gas was 200ml / min, which was always introduced during the reduction process), and the temperature was raised to 400°C at 5°C / min, maintained for 5 hours, and the catalyst was reduced to obtain a catalyst marked as Ni 10 Co1Cu1 / CaO-ZrO2. The dispersion of the active components in the catalyst was 77%, as measured and calculated using a chemical adsorption instrument.

[0056] Example 4

[0057] Ni(NO3)2·6H2O, Co(NO3)2·6H2O and Cu(NO3)2·3H2O were dissolved in deionized water in a molar ratio of 10:3:1 to form a solution, and stirred at room temperature for half an hour. Then, the CaO-ZrO2 prepared in Example 1 was added to the precursor solution at an active component loading of 45wt%, and continuously stirred and ultrasonicated for half an hour to form a mixture, which was allowed to stand in a vacuum oven for 48 hours. After standing, the mixture was placed in a 75°C vacuum drying oven and dried for 12 hours. The dried mixture was placed in a muffle furnace and heated to 800°C at a heating rate of 8°C / min and calcined for 5 hours. Then, 20vol% H / Ar mixed gas was introduced into the tubular furnace (the flow rate of the mixed gas was 200ml / min, which was always introduced during the reduction process), and the temperature was raised to 400°C at 5°C / min, maintained for 2 hours, and the catalyst was reduced to obtain a catalyst marked as Ni 10 Co3Cu1 / CaO-ZrO2. The dispersion of the active components in the catalyst was 75%, as measured and calculated using a chemical adsorption instrument.

[0058] Example 5

[0059] Ni(NO₃)₂·6H₂O, Co(NO₃)₂·6H₂O, and Cu(NO₃)₂·3H₂O were dissolved in deionized water at a molar ratio of 5:2:1 to form a solution, which was stirred at room temperature for half an hour. The CaO-ZrO₂ prepared in Example 1 was then added to the precursor solution at an active component loading of 35 wt%, stirred continuously, and ultrasonicated for half an hour to form a mixture, which was then allowed to stand in a vacuum oven for 24 hours. After standing, the mixture was dried in an 80°C vacuum drying oven for 12 hours. The dried mixture was then heated to 400°C in a muffle furnace at a heating rate of 8°C / min for 5 hours. A 5 vol% H / Ar mixture (at a flow rate of 200 ml / min, which was maintained throughout the reduction process) was then introduced into the tube furnace, heated to 400°C at 5°C / min, and held for 15 hours to yield the catalyst, labeled Ni₅Co₂Cu₁ / CaO-ZrO₂. The dispersion of the active components in the catalyst was calculated and measured using a chemical adsorption instrument and was found to be 80%.

[0060] Example 6

[0061] 0.96g of Ni prepared in Example 2 was added 10 The Co2Cu1 / CaO-ZrO2 catalyst, 25 ml of methanol, 50 ml of toluene solvent (volume ratio = 1:2), and 9.6 g of IPN were added to an autoclave. The autoclave was sealed and the air inside was replaced three times with nitrogen and hydrogen (0.3-0.8 MPa). The autoclave was placed in a heating mantle. When the autoclave temperature reached 90°C, hydrogen was added to 4 MPa, a magnetic stirrer was turned on, and the reaction timer was started. After reacting for 1 hour, the mixture was cooled and separated, and the supernatant was analyzed by gas chromatography. The gas phase results are shown in Table 1.

[0062] Example 7

[0063] 0.96 g of Ni prepared in Example 3 was added 10 The Co1Cu1 / CaO-ZrO2 catalyst, 25 ml of methanol, 50 ml of toluene solvent (volume ratio = 1:2), and 9.6 g of IPN were added to an autoclave. The reactor was sealed, and the air inside was replaced three times with nitrogen and hydrogen (0.3-0.8 MPa). The reactor was then placed in a heating mantle. When the temperature inside the autoclave reached 90°C, hydrogen was added to 4 MPa, a magnetic stirrer was activated, and the reaction timer was started. After reacting for 1 hour, the reaction mixture was cooled, separated, and the supernatant analyzed by gas chromatography. The gas phase results are shown in Table 1.

[0064] Example 8

[0065] 0.96 g of Ni prepared in Example 4 was added 10Co3Cu1 / CaO-ZrO2 catalyst, 25 ml of methanol, 50 ml of toluene solvent (volume ratio = 1:2), and 9.6 g of IPN were added to an autoclave. The reactor was sealed, and the air inside was replaced three times with nitrogen and hydrogen (0.3-0.8 MPa). The reactor was then placed in a heating mantle. When the temperature inside the autoclave reached 90°C, hydrogen was added to 4 MPa, a magnetic stirrer was activated, and the reaction timer was started. After reacting for 1 hour, the reaction mixture was cooled, separated, and the supernatant analyzed by gas chromatography. The gas phase results are shown in Table 1.

[0066] Example 9

[0067] 0.96 g of the Ni5Co2Cu1 / CaO-ZrO2 catalyst prepared in Example 5, 25 ml of methanol, 50 ml of toluene solvent (volume ratio = 1:2), and 9.6 g of IPN were added to an autoclave. The autoclave was sealed, and the air inside was replaced three times with nitrogen and hydrogen (0.3-0.8 MPa). The autoclave was then placed in a heating mantle. When the autoclave temperature reached 90°C, hydrogen was added to 4 MPa, a magnetic stirrer was activated, and the reaction timer was started. After reacting for 1 hour, the mixture was cooled, separated, and the supernatant analyzed by gas chromatography. The gas phase results are shown in Table 1.

[0068] Example 10

[0069] After the reaction in Example 6 was completed and cooled and separated, the obtained solid was recovered and used as a catalyst for a cyclic reaction. The reaction conditions were exactly the same as in Example 6. The recovered catalyst was circulated 10 times for a cycle life test. The specific results are shown in Table 2.

[0070] Comparative Example 1

[0071] The difference from Example 6 is that the catalyst is different, and the catalyst is commercially available Raney nickel. The other operating conditions are exactly the same as those of Example 6. After reacting for 1 hour, the mixture is cooled and separated, and the supernatant is analyzed by gas chromatography. The gas phase results are shown in Table 1.

[0072] Comparative Example 2

[0073] The difference from Example 6 is that the catalyst is different. The catalyst is commercially available supported nickel (Ni content of 40-45 wt%, Shanghai Hanlu New Material Technology Co., Ltd.). The other operating conditions are exactly the same as those in Example 6. After the reaction is completed for 1 hour, the mixture is cooled and separated. The supernatant is analyzed by gas chromatography. The gas phase results are shown in Table 1.

[0074] Comparative Example 3

[0075] The difference from Example 6 is that the catalyst is different, the catalyst is Ni 10 Co2 / CaO-ZrO2. Other operating conditions were exactly the same as those in Example 6. After 1 hour of reaction, the mixture was cooled and separated. The supernatant was analyzed by gas chromatography. The gas phase results are shown in Table 1.

[0076] The specific preparation method of the catalyst is as follows:

[0077] Ni(NO3)2·6H2O and Co(NO3)2·6H2O were dissolved in deionized water at a molar ratio of 10:2 to form a solution, and stirred at room temperature for half an hour. Then, the CaO-ZrO2 prepared in Example 1 was added to the precursor solution at an active component loading of 40wt%, and continuously stirred and ultrasonicated for half an hour to form a mixture, which was allowed to stand in a vacuum oven for 24 hours. After standing, the mixture was placed in an 80°C vacuum drying oven and dried for 12 hours. The dried mixture was placed in a muffle furnace and heated to 550°C at a heating rate of 8°C / min and calcined for 10 hours. Then, a 10% H / Ar mixed gas was introduced into the tubular furnace, and the temperature was raised to 400°C at 5°C / min, maintained for 5 hours, and reduced to obtain a catalyst, which was marked as Ni 10 Co2 / CaO-ZrO2.

[0078] Comparative Example 4

[0079] The difference from Example 6 is that the catalyst is different, namely Ni / CaO-ZrO2. The other operating conditions are exactly the same as those in Example 6. After reacting for 1 hour, the mixture is cooled and separated, and the supernatant is analyzed by gas chromatography. The gas phase results are shown in Table 1.

[0080] The specific preparation method of the catalyst is as follows:

[0081] Dissolve Ni(NO3)2·6H2O in deionized water to form a solution, and stir at room temperature for half an hour. Then, add the CaO-ZrO2 prepared in Example 1 to the precursor solution at an active component loading of 40wt%, continuously stir and ultrasonicate for half an hour to form a mixture, and let it stand in a vacuum oven for 24 hours. After standing, the mixture is placed in an 80°C vacuum drying oven and dried for 12 hours. The dried mixture is placed in a muffle furnace and heated to 550°C at a heating rate of 8°C / min and calcined for 10 hours. Then, a 10% H / Ar mixed gas is introduced into a tubular furnace, and the temperature is raised to 400°C at 5°C / min, maintained for 5 hours, and reduced to obtain a catalyst, which is labeled Ni / CaO-ZrO2.

[0082] Comparative Example 5

[0083] The difference from Example 6 is that the catalyst support is different; the catalyst support used is mesoporous SiO2 molecular sieve KIT-6. Other operating conditions are identical to those of Example 6. After 1 hour of reaction, the mixture is cooled and separated, and the supernatant is analyzed by gas chromatography. The gas phase results are shown in Table 1.

[0084] The specific preparation method of the catalyst is as follows:

[0085] Ni(NO3)2·6H2O, Co(NO3)2·6H2O and Cu(NO3)2·3H2O were dissolved in deionized water at a molar ratio of 10:2:1 to form a solution, and stirred at room temperature for half an hour. Then, the mesoporous SiO2 molecular sieve KIT-6 was added to the precursor solution at an active component loading of 40wt%, continuously stirred and ultrasonicated for half an hour to form a mixture, and allowed to stand in a vacuum oven for 24 hours. After standing, the mixture was placed in an 80°C vacuum drying oven and dried for 12 hours. The dried mixture was placed in a muffle furnace and heated to 550°C at a heating rate of 8°C / min and calcined for 10 hours. Then, a 10% H / Ar mixed gas was introduced into the tubular furnace, and the temperature was raised to 400°C at 5°C / min, maintained for 5 hours, and reduced to obtain a catalyst, which was labeled Ni 10 Co2Cu1 / SiO2.

[0086] Table 1 Catalytic IPN reactor hydrogenation test results

[0087]

[0088]

[0089] Table 2 Catalytic IPN reactor hydrogenation life test results

[0090] IPN conversion rate / % MXDA yield / % Loop 1 100 99.9 Loop 2 100 99.7 Loop 3 100 99.6 Loop 4 100 99.8 Loop 5 100 99.8 Loop 6 100 99.7 Loop 7 100 99.6 Loop 8 100 99.3 Loop 9 100 99.2 Loop 10 100 99.1 Loop 11 100 99.2

[0091] Note: Cycle 1 is the reaction of Example 6.

[0092] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a hydrogenation catalyst, characterized in that: The steps include: a. The mesoporous CaO-ZrO2 was added to a precursor solution containing Ni, Co, and Cu, and ultrasonicated, allowed to stand, and dried to obtain a catalyst precursor; b. calcining the catalyst precursor to obtain a calcined solid; c. reducing the calcined solid to obtain a hydrogenation catalyst; The mesoporous CaO-ZrO2 was prepared by the following method: 1) adding an alcohol solution of zirconium n-propoxide and acetylacetone to an alcohol solution of calcium nitrate and Pluronic P123 under stirring to obtain a mixed solution; 2) adjusting the pH of the mixed solution to 5-6 and then aging it to obtain a gel; 3) refluxing the gel in an alkaline solution, and washing the gel after the reflux to obtain a solid material; 4) calcining the solid material to obtain mesoporous CaO-ZrO 2； The hydrogenation catalyst uses mesoporous CaO-ZrO2 as a carrier; Ni, Co, and Cu as active components, wherein the element molar ratio of Ni, Co, and Cu is 5-10:1-3:1, and the dispersion of the active components is 70-86%.

2. The preparation method according to claim 1, characterized in that Calculated as metal elements, the active component accounts for 30% to 45% of the total weight of the hydrogenation catalyst.

3. The preparation method according to claim 1, characterized in that The aging temperature in step 2) is 45-80° C., and the aging time is 6-48 hours.

4. The hydrogenation catalyst according to claim 1, characterized in that In step 4), drying and grinding are sequentially performed before calcination; the drying temperature is 60-120° C. and the drying time is 12-24 hours.

5. The preparation method according to claim 1, characterized in that After the reduction in step c, a gas phase passivation method is further used for passivation treatment, and the specific operation is: an inert gas containing a mass fraction of 0.5-3% oxygen is introduced for passivation.

6. The preparation method according to claim 1, characterized in that In step a, the mixture is allowed to stand and dried in a vacuum environment; the standing time is 12 to 48 hours; the drying temperature is 70 to 85° C., and the drying time is 12 to 24 hours.

7. The preparation method according to claim 1, characterized in that The calcination temperature in step b is 200-800° C. and the calcination time is 5-8 hours.

8. A hydrogenation catalyst prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the hydrogenation catalyst according to claim 8 in the preparation of meta-xylylenediamine.

Images