Acetonitrile hydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention discloses an acetonitrile hydrogenation catalyst as well as a preparation method and application thereof. The acetonitrile hydrogenation catalyst comprises a carrier and an active component loaded on the carrier, the carrier is selected from at least one of gamma-Al2O3, SiO2, MOR and a ZSM-5 molecular sieve; the active component comprises an active element; the active elements comprise Ni and Co. The catalyst can effectively catalyze acetonitrile hydrogenation under mild reaction conditions. The supported catalyst provided by the invention has excellent reaction performances such as high acetonitrile conversion rate and high monoethylamine selectivity in acetonitrile hydrogenation reaction, the reaction condition is mild, the operation is simple, and the catalyst is easy to prepare and can be recycled.

Description

Technical Field

[0001] The present application relates to an acetonitrile hydrogenation catalyst, a preparation method thereof and an application thereof, and belongs to the field of chemistry and chemical engineering. Background Art

[0002] Acetonitrile is a byproduct of acrylonitrile production. One ton of acrylonitrile will produce about 100 kg of acetonitrile byproduct. Due to the limited market demand for acetonitrile, a large amount of acetonitrile is in stock, which not only brings great inventory pressure to acrylonitrile manufacturers, but some companies even destroy the excess acetonitrile by incineration, which not only wastes resources but also seriously pollutes the environment. Therefore, converting acetonitrile into ethylamine compounds with more economic value has received more and more attention.

[0003] Currently, the main catalyst for nitrile hydrogenation in industry is Raney Ni, but its preparation process involves alkali filtration, which causes environmental pollution, and has low catalytic activity. The catalyst is fragile, thus having a short lifespan, and is prone to causing blockage of the reaction gas. Summary of the invention

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a cleaner and more efficient method for preparing an acetonitrile hydrogenation catalyst.

[0005] In one aspect of the present application, an acetonitrile hydrogenation catalyst is provided, wherein the acetonitrile hydrogenation catalyst comprises a carrier and an active component supported on the carrier;

[0006] The carrier is selected from at least one of γ-Al2O3, SiO2, MOR, and ZSM-5 molecular sieve;

[0007] The active components include active elements;

[0008] The active elements include Ni and Co;

[0009] The acetonitrile hydrogenation catalyst is nanoparticles with a particle size of 5 to 15 nm.

[0010] In the present application, the acetonitrile hydrogenation catalyst is a supported NiCo catalyst, which has the morphology of uniformly dispersed nanoparticles. The particle size of the supported NiCo catalyst is 5-15 nm.

[0011] Optionally, in the acetonitrile hydrogenation catalyst, the mass percentage of the active component is 0.1% to 10% of the mass of the acetonitrile hydrogenation catalyst, wherein the mass of the active component is calculated based on the mass of the active element;

[0012] In the acetonitrile hydrogenation catalyst, the mass of the carrier accounts for 10 to 99% of the mass of the acetonitrile hydrogenation catalyst.

[0013] Optionally, in the active element, the molar ratio of Ni to Co is 1:10 to 10:1.

[0014] Optionally, in the active element, the molar ratio of Ni to Co independently selected from any value of 1:10, 1:8, 1:6, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 6:1, 8:1, 10:1 or any range value between any two of the above.

[0015] In another aspect of the present application, there is provided a method for the above-mentioned acetonitrile hydrogenation catalyst, the method comprising:

[0016] (1) Adding a nickel salt, a cobalt salt and a carrier to oleic acid to obtain a mixture I;

[0017] (2) Mixing the mixture I with oleylamine and reacting to obtain the acetonitrile hydrogenation catalyst.

[0018] Optionally, the nickel salt is at least one of a nitrate, a halide, a complex, a hydrohalic acid, and a hydrohalide of divalent nickel;

[0019] The cobalt salt is at least one of a sulfate, a nitrate, a halide, a complex, a hydrohalic acid, and a hydrohalide of divalent cobalt;

[0020] The carrier is at least one of γ-Al2O3, SiO2, MOR, and ZSM-5 molecular sieve.

[0021] Optionally, the molar ratio of the nickel salt to the cobalt salt is 1:10 to 10:1.

[0022] Optionally, the molar ratio of the nickel salt to the cobalt salt independently selected from any value of 1:10, 1:8, 1:6, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 6:1, 8:1, 10:1 or any range value between any two of the above.

[0023] Optionally, in the mixture I, the concentration of the nickel salt is 0.0001 to 0.05 mol / L;

[0024] In the mixture I, the concentration of the cobalt salt is 0.0001 to 0.05 mol / L;

[0025] The solid-liquid ratio of the carrier to the oleic acid is 1:1 to 1:5.

[0026] Optionally, the concentration of the nickel salt independently selected from any value of 0.0001 mol / L, 0.0005 mol / L, 0.001 mol / L, 0.005 mol / L, 0.01 mol / L, 0.05 mol / L or any range value between any two of the above.

[0027] Optionally, the concentration of the cobalt salt is independently selected from any value of 0.0001 mol / L, 0.0005 mol / L, 0.001 mol / L, 0.005 mol / L, 0.01 mol / L, 0.05 mol / L or any range value between any two of the above.

[0028] Optionally, the solid-liquid ratio of the carrier to the oleic acid is independently selected from any value of 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5 or any range value between any two of the above.

[0029] Optionally, the volume ratio of oleylamine to oleic acid is 3:7 to 7:3.

[0030] Optionally, the volume ratio of oleylamine to oleic acid is independently selected from any value of 3:7, 3:5, 1, 5:3, 7:3 or any range value between any two of the above.

[0031] Optionally, the temperature of the reaction is 170 to 250 °C and the time is 1.0 to 12.0 h.

[0032] Optionally, the temperature of the reaction is independently selected from any value of 170 °C, 200 °C, 210 °C, 220 °C, 250 °C or any range value between any two of the above.

[0033] Optionally, the time of the reaction is independently selected from any value of 1 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h or any range value between any two of the above.

[0034] Optionally, the method further includes:

[0035] After the reaction, a solvent is added to the mixture obtained from the reaction, and the acetonitrile hydrogenation catalyst is obtained after separation, washing, and drying;

[0036] wherein the solvent is ethanol or a mixed solution of water and ethanol.

[0037] As a specific embodiment, the preparation method of the catalyst is realized by the following technical solution:

[0038] (1) Adding a nickel salt, a cobalt salt, and a carrier to oleic acid to obtain a mixture A;

[0039] (2) After uniformly dispersing the mixture A, oleylamine is added to obtain a mixture B;

[0040] (3) Reacting the mixture B at 170 to 250 °C to obtain a mixture C;

[0041] (4) Solvent D is added to mixture C, and after multiple separations, washings, and drying, the supported NiCo catalyst is obtained.

[0042] In another aspect of the present application, a method for preparing ethylamine by hydrogenating acetonitrile is provided, and the method includes:

[0043] A raw material containing acetonitrile and hydrogen is contacted with a catalyst to react to obtain ethylamine;

[0044] Among them, the catalyst is selected from the above-mentioned acetonitrile hydrogenation catalysts.

[0045] Optionally, in the raw material, the molar ratio of acetonitrile to hydrogen is 15:1 to 1:1;

[0046] The mass space velocity of acetonitrile is 0.2 to 2 h -1 .

[0047] Optionally, the molar ratio of acetonitrile to hydrogen independently selects any value among 15:1, 8:1, 6:1, 1:1 or any range value between any two of the above.

[0048] Optionally, the mass space velocity of acetonitrile independently selects any value among 0.2 h -1 , 0.5 h -1 , 0.8 h -1 , 1 h -1 , 1.2 h -1 , 1.5 h -1 , 1.8 h -1 , 2 h -1 or any range value between any two of the above.

[0049] Optionally, the temperature of the reaction is 150 - 200 °C;

[0050] The pressure of the reaction is 0.2 to 5 MPa.

[0051] Optionally, the temperature of the reaction independently selects any value among 150 °C, 160 °C, 170 °C, 180 °C, 190 °C, 200 °C or any range value between any two of the above.

[0052] Optionally, the pressure of the reaction independently selects any value among 0.2 MPa, 0.5 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa, 5 MPa or any range value between any two of the above.

[0053] Optionally, the application further includes reducing the acetonitrile hydrogenation catalyst before the reaction;

[0054] The reduction conditions are as follows: reduction is carried out for 1 - 10 h under the temperature condition of 400 - 550 °C in a hydrogen atmosphere.

[0055] The beneficial effects that can be produced by this application include:

[0056] (1) The inventive point of this application lies in providing a simple and efficient preparation method for a supported NiCo catalyst. Using oleylamine as the main reducing agent and oleic acid as the surfactant, a supported NiCo catalyst with uniformly dispersed nanoparticles, high catalytic activity, and strong stability is successfully prepared. The preparation method has a simple process and easily controllable reaction conditions.

[0057] (2) The method of this application has a simple process and easily controllable reaction conditions. It is a simple and efficient preparation method for a NiCo catalyst. Using this catalyst, acetonitrile hydrogenation can be effectively catalyzed under mild reaction conditions. The supported catalyst of the present invention has excellent reaction performance such as high acetonitrile conversion rate and high monoethylamine selectivity in the acetonitrile hydrogenation reaction. The reaction conditions are mild, the operation is simple, and the catalyst is easy to prepare and recyclable. Specific Embodiments

[0058] The following further details this application with reference to embodiments, but this application is not limited to these embodiments.

[0059] Unless otherwise specified, the raw materials in the embodiments of this application are all purchased through commercial channels.

[0060] Example 1

[0061] (1) Weigh 10 g of γ - Al2O3, and calculate the masses of nickel nitrate and cobalt nitrate according to the catalyst active component being 1% and the molar ratio of Ni to Co being 1:1. Weigh 0.49 g of nickel nitrate and 0.49 g of cobalt nitrate, add the above substances to 25.0 mL of oleic acid, and stir at room temperature for 0.5 h to obtain a mixed solution A;

[0062] (2) Accurately weigh 25.0 mL of oleylamine and add it to the mixed solution A in (1) such that the volume ratio of oleylamine to oleic acid is 1:1;

[0063] (3) Place the solution in (2) in an oil bath at 250 °C and stir magnetically for 1.0 h to obtain a brown - black sol - like liquid;

[0064] (4) Add ethanol to the brown - black sol - like liquid in (3), perform centrifugal separation, and then wash 5 times with a mixed solution of deionized water and ethanol to obtain NiCo / γ - Al2O3, and dry it for later use.

[0065] Example 2

[0066] (1) Weigh 10 g of γ-Al2O3, and calculate the masses of nickel nitrate and cobalt nitrate according to the catalyst active component being 1% and the molar ratio of Ni to Co being 1:1. Weigh 0.49 g of nickel nitrate and 0.49 g of cobalt nitrate, add the above substances to 25.0 mL of oleic acid, and stir at room temperature for 0.5 h to obtain a mixed solution A;

[0067] (2) Accurately weigh 25.0 mL of oleylamine, add it to the mixed solution A in (1) such that the volume ratio of oleylamine to oleic acid is 1:1;

[0068] (3) Place the solution in (2) in an oil bath at 210 °C and stir magnetically for 6.0 h to obtain a brownish-black sol-like liquid;

[0069] (4) Add ethanol to the brownish-black sol-like liquid in (3), centrifuge, and then wash 5 times with a mixed solution of deionized water and ethanol to obtain NiCo / γ-Al2O3, and dry it for later use.

[0070] Example 3

[0071] (1) Weigh 10 g of γ-Al2O3, and calculate the masses of nickel nitrate and cobalt nitrate according to the catalyst active component being 1% and the molar ratio of Ni to Co being 1:1. Weigh 0.49 g of nickel nitrate and 0.49 g of cobalt nitrate, add the above substances to 25.0 mL of oleic acid, and stir at room temperature for 0.5 h to obtain a mixed solution A;

[0072] (2) Accurately weigh 25.0 mL of oleylamine, add it to the mixed solution A in (1) such that the volume ratio of oleylamine to oleic acid is 1:1;

[0073] (3) Place the solution in (2) in an oil bath at 170 °C and stir magnetically for 12.0 h to obtain a brownish-black sol-like liquid;

[0074] (4) Add ethanol to the brownish-black sol-like liquid in (3), centrifuge, and then wash 5 times with a mixed solution of deionized water and ethanol to obtain NiCo / γ-Al2O3, and dry it for later use.

[0075] Example 4

[0076] (1) Weigh 10 g of γ-Al2O3, and calculate the masses of nickel nitrate and cobalt nitrate according to the catalyst active component being 1% and the molar ratio of Ni to Co being 10:1. Weigh 4.9 g of nickel nitrate and 0.49 g of cobalt nitrate, add the above substances to 25.0 mL of oleic acid, and stir at room temperature for 0.5 h to obtain a mixed solution A;

[0077] (2) Accurately weigh 25.0 mL of oleylamine, add it to the mixed solution A in (1) such that the volume ratio of oleylamine to oleic acid is 1:1;

[0078] (3) Place the solution in (2) in an oil bath at 210 °C and stir magnetically for 6.0 h to obtain a brownish-black sol-like liquid;

[0079] (4) Add ethanol to the brownish-black sol-like liquid in (3), centrifuge, and then wash 5 times with a mixed solution of deionized water and ethanol to obtain NiCo / γ-Al2O3, and dry it for later use.

[0080] Example 5

[0081] (1) Weigh 10 g of γ-Al2O3, and calculate the masses of nickel nitrate and cobalt nitrate according to a catalyst active component of 1% and a molar ratio of Ni to Co of 3:1. Weigh 1.47 g of nickel nitrate and 0.49 g of cobalt nitrate, add the above substances to 25.0 mL of oleic acid, and stir at room temperature for 0.5 h to obtain a mixed solution A;

[0082] (2) Accurately weigh 25.0 mL of oleylamine and add it to the mixed solution A in (1) such that the volume ratio of oleylamine to oleic acid is 1:1;

[0083] (3) Place the solution in (2) in an oil bath at 210 °C and stir magnetically for 6.0 h to obtain a brownish-black sol-like liquid;

[0084] (4) Add ethanol to the brownish-black sol-like liquid in (3), centrifuge, and then wash 5 times with a mixed solution of deionized water and ethanol to obtain NiCo / γ-Al2O3, and dry it for later use.

[0085] Example 6

[0086] (1) Weigh 10 g of γ-Al2O3, and calculate the masses of nickel nitrate and cobalt nitrate according to a catalyst active component of 1% and a molar ratio of Ni to Co of 1:3. Weigh 0.49 g of nickel nitrate and 1.47 g of cobalt nitrate, add the above substances to 25.0 mL of oleic acid, and stir at room temperature for 0.5 h to obtain a mixed solution A;

[0087] (2) Accurately weigh 25.0 mL of oleylamine and add it to the mixed solution A in (1) such that the volume ratio of oleylamine to oleic acid is 1:1;

[0088] (3) Place the solution in (2) in an oil bath at 210 °C and stir magnetically for 6.0 h to obtain a brownish-black sol-like liquid;

[0089] (4) Add ethanol to the brownish-black sol-like liquid in (3), centrifuge, and then wash 5 times with a mixed solution of deionized water and ethanol to obtain NiCo / γ-Al2O3, and dry it for later use.

[0090] Example 7

[0091] (1) Weigh 10 g of γ-Al2O3, and calculate the masses of nickel nitrate and cobalt nitrate according to the catalyst active component being 1% and the molar ratio of Ni to Co being 1:10. Weigh 0.49 g of nickel nitrate and 4.9 g of cobalt nitrate, add the above substances to 25.0 mL of oleic acid, and stir at room temperature for 0.5 h to obtain a mixed solution A;

[0092] (2) Accurately weigh 25.0 mL of oleylamine, add it to the mixed solution A in (1) such that the volume ratio of oleylamine to oleic acid is 1:1;

[0093] (3) Place the solution in (2) in an oil bath at 210 °C and stir magnetically for 6.0 h to obtain a brownish-black sol-like liquid;

[0094] (4) Add ethanol to the brownish-black sol-like liquid in (3), centrifuge, and then wash 5 times with a mixed solution of deionized water and ethanol to obtain NiCo / γ-Al2O3, and dry it for later use.

[0095] Example 8

[0096] (1) Weigh 10 g of γ-Al2O3, and calculate the masses of nickel nitrate and cobalt nitrate according to the catalyst active component being 1% and the molar ratio of Ni to Co being 1:1. Weigh 0.49 g of nickel nitrate and 0.49 g of cobalt nitrate, add the above substances to 15.0 mL of oleic acid, and stir at room temperature for 0.5 h to obtain a mixed solution A;

[0097] (2) Accurately weigh 35.0 mL of oleylamine, add it to the mixed solution A in (1) such that the volume ratio of oleylamine to oleic acid is 3:7;

[0098] (3) Place the solution in (2) in an oil bath at 210 °C and stir magnetically for 6.0 h to obtain a brownish-black sol-like liquid;

[0099] (4) Add ethanol to the brownish-black sol-like liquid in (3), centrifuge, and then wash 5 times with a mixed solution of deionized water and ethanol to obtain NiCo / γ-Al2O3, and dry it for later use.

[0100] Example 9

[0101] (1) Weigh 10 g of γ-Al2O3, and calculate the masses of nickel nitrate and cobalt nitrate according to the catalyst active component being 1% and the molar ratio of Ni to Co being 1:1. Weigh 0.49 g of nickel nitrate and 0.49 g of cobalt nitrate, add the above substances to 35.0 mL of oleic acid, and stir at room temperature for 0.5 h to obtain a mixed solution A;

[0102] (2) Accurately weigh 15.0 mL of oleylamine, add it to the mixed solution A in (1) such that the volume ratio of oleylamine to oleic acid is 7:3;

[0103] (3) Place the solution in (2) in an oil bath at 210 °C and magnetically stir for 6.0 h to obtain a brownish-black sol-like liquid;

[0104] (4) Add ethanol to the brownish-black sol-like liquid in (3), centrifuge, and then wash 5 times with a mixed solution of deionized water and ethanol to obtain NiCo / γ-Al2O3, and dry it for later use.

[0105] Comparative Example

[0106] (1) Weigh 10 g of γ-Al2O3, calculate the mass of nickel nitrate according to the catalyst active component of 1%, weigh 0.49 g of nickel nitrate, add the above substances to 25.0 mL of oleic acid, and stir at room temperature for 0.5 h to obtain a mixed solution A;

[0107] (2) Accurately weigh 25.0 mL of oleylamine and add it to the mixed solution A in (1) so that the volume ratio of oleylamine to oleic acid is 1:1;

[0108] (3) Place the solution in (2) in an oil bath at 210 °C and magnetically stir for 1.0 h to obtain a brownish-black sol-like liquid;

[0109] (4) Add ethanol to the brownish-black sol-like liquid in (3), centrifuge, and then wash 5 times with a mixed solution of deionized water and ethanol to obtain Ni / γ-Al2O3, and dry it for later use.

[0110] Test Example

[0111] Use the catalysts prepared in Examples 1-9 and the comparative example above for acetonitrile hydrogenation reaction. The specific implementation process is as follows: Press the catalyst into tablets and then crush them into particles of 20-40 mesh. Weigh 1 g of catalyst particles and place them in a fixed-bed reactor with an inner diameter of 10 mm. Both ends of the fixed-bed reactor are filled with 20-40 mesh quartz sand; before the reaction, the catalyst is reduced with H2 gas at a flow rate of 30 mL / min, the reduction temperature is 400 °C, and the reduction time is 2 h. Then, acetonitrile is pumped into the reactor in advance at a mass space velocity of 1 h -1 The rate is pumped into the reactor, and the flow rate of hydrogen is 136 mL / min. Acetonitrile and hydrogen are introduced into the fixed-bed reactor for catalytic reaction to obtain reaction products. The reaction products are analyzed by Agilent 7890A gas chromatography, and the results are shown in Table 1 below.

[0112] Acetonitrile conversion rate = amount of acetonitrile converted in the reaction (mol) / acetonitrile feed amount (mol) × 100%

[0113] Ethylamine selectivity = (amount of ethanol converted to ethylamine in the reaction (mol) / amount of acetonitrile converted in the reaction (mol)) × 100%

[0114] Table 1 Performance of the catalysts prepared in Examples 1 - 9.

[0115] Catalyst Conversion rate of acetonitrile Selectivity of monoethylamine Example 1 90.81％ 90.31％ Example 2 92.22％ 92.59％ Example 3 87.25％ 89.48％ Example 4 97.41％ 90.87％ Example 5 93.65％ 91.69％ Example 6 89.54％ 87.63％ Example 7 81.30％ 84.35％ Example 8 86.56％ 86.97％ Example 9 89.21％ 90.46％ Comparative example 60.10％ 70.20％

[0116] As described above, these are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, making some changes or modifications using the technical content disclosed above is equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A acetonitrile hydrogenation catalyst, characterized in that, The acetonitrile hydrogenation catalyst comprises a support and an active component supported on the support; The support is selected from at least one of γ-Al2O3, SiO2, MOR, and ZSM-5 molecular sieves; The active component comprises active elements; The active elements include Ni and Co; The acetonitrile hydrogenation catalyst is nanoparticles with a particle size of 5 to 15 nm.

2. The acetonitrile hydrogenation catalyst according to claim 1, characterized in that, In the acetonitrile hydrogenation catalyst, the mass percentage of the active component is 0.1% to 10% of the mass of the acetonitrile hydrogenation catalyst, wherein the mass of the active component is calculated based on the mass of the active elements; In the acetonitrile hydrogenation catalyst, the mass of the support accounts for 10 to 99% of the mass of the acetonitrile hydrogenation catalyst.

3. The acetonitrile hydrogenation catalyst according to claim 1, characterized in that, In the active elements, the molar ratio of Ni to Co is 1:10 to 10:

1.

4. A method for preparing the acetonitrile hydrogenation catalyst according to any one of claims 1 to 3, characterized in that, The method comprises: (1) Adding a nickel salt, a cobalt salt, and a support to oleic acid to obtain mixture A; (2) Mixing mixture A with oleylamine and reacting to obtain the acetonitrile hydrogenation catalyst.

5. The method according to claim 4, characterized in that, The nickel salt is at least one of nitrates, halides, complexes, hydrohalic acids, and hydrohalides of divalent nickel; The cobalt salt is at least one of sulfates, nitrates, halides, complexes, hydrohalic acids, and hydrohalides of divalent cobalt; The support is at least one of γ-Al2O3, SiO2, MOR, and ZSM-5 molecular sieves; Preferably, the molar ratio of the nickel salt to the cobalt salt is 1:10 to 10:

1.

6. The method according to claim 4, characterized in that, In mixture A, the concentration of the nickel salt is 0.0001 to 0.05 mol / L; In mixture A, the concentration of the cobalt salt is 0.0001 to 0.05 mol / L; The solid-liquid ratio of the support to the oleic acid is 1:1 to 1:

5.

7. The method according to claim 4, characterized in that, The volume ratio of the oleylamine to the oleic acid is 3:7 to 7:3; Preferably, the temperature of the reaction is 170 to 250 °C, and the time is 1.0 to 12.0 h.

8. The method according to claim 4, characterized in that, The method further comprises: After the reaction, adding a solvent to the obtained mixture B, separating, washing, and drying to obtain the acetonitrile hydrogenation catalyst; wherein the solvent is ethanol or a mixed solution of water and ethanol.

9. A method for preparing ethylamine by acetonitrile hydrogenation, characterized in that, The method comprises: A raw material containing acetonitrile and hydrogen is contacted with the acetonitrile hydrogenation catalyst, and the reaction obtains ethylamine; wherein the catalyst is selected from the acetonitrile hydrogenation catalysts described in any one of claims 1 to 3.

10. The method according to claim 9, wherein In the raw material, the molar ratio of acetonitrile to hydrogen is 15:1 to 1:1; The mass space velocity of acetonitrile is 0.2 to 2 h -1 ; Preferably, the temperature of the reaction is 150 - 200 °C; The pressure of the reaction is 0.2 to 5 MPa; Preferably, the application further comprises reducing the acetonitrile hydrogenation catalyst before the reaction; The conditions for the reduction are: reducing at a temperature of 400 to 550 °C for 1 to 10 h under a hydrogen atmosphere.