CN118287087A - Double non-noble metal catalyst Co-Ni/La2O3And preparation method and application thereof in catalyzing selective hydrogenation of m-xylylenediamine in heterogeneous system - Google Patents

Abstract

The invention relates to a double non-noble metal catalyst Co-Ni/La ₂O₃, a preparation method thereof and application thereof in catalyzing selective hydrogenation of m-xylylenediamine in a heterogeneous system, belonging to the field of catalytic hydrogenation, wherein the catalyst is prepared by taking cobalt nitrate hexahydrate as a cobalt source, nickel nitrate hexahydrate as a nickel source and La ₂O₃ as a carrier, loading active metals Co and Ni on La ₂O₃, and placing the catalyst in a tubular furnace for reduction and passivation. Under the conditions of 50mg of catalyst, 0.5g of m-xylylenediamine, 8MPa of hydrogen pressure, 180 ℃ of temperature and 5 hours of reaction, the conversion rate of the m-xylylenediamine reaches 100 percent, and the selectivity of the 1, 3-cyclohexanediamine reaches more than 70 percent. The preparation method is simple, low in cost, high in target product selectivity, excellent in catalytic performance, easy to separate and has an industrialization prospect.

Description

A dual non-precious metal catalyst Co-Ni/La2O3 and its preparation method and application in catalyzing the selective hydrogenation of m-phenylenediamine in a heterogeneous system

Technical Field

The invention belongs to the field of catalytic hydrogenation, and specifically relates to a dual non-precious metal catalyst Co-Ni _{/ La2O3} and a preparation method thereof, and an application of the catalyst in catalyzing the selective hydrogenation of m-xylylenediamine to 1,3-cyclohexylenediamine in a heterogeneous system.

Background technique

1,3-Cyclohexyldimethylamine is widely used in the synthesis of desulfurizers, emulsifiers, pesticides, etc. It can be prepared by hydrogenating the benzene ring of aromatic amines to produce cyclohexylamine. Precious metal catalysts are widely used in the hydrogenation of aromatic amines, but precious metals are expensive, so the development of non-precious metal-based catalysts with excellent catalytic performance is of great significance in actual industrial production and application.

At present, the most atom-economical route is to catalyze the hydrogenation of benzene diamine to cyclohexane diamine, but most of the catalysts used are precious metal catalysts, such as Ru. Zhao et al. used Ru/C with a loading of 8.5wt% as a catalyst, isopropanol as a solvent, and without additives. The conversion rate of o-phenylenediamine reached 99.5% at a reaction temperature of 160°C and a pressure of 7MPa, and the yield of 1,2-cyclohexane diamine reached 77.3%. Wang Tao et al. from Dalian Institute of Chemical Physics used Ru/C with a loading of 5wt% as a catalyst, isopropanol as a solvent, and sodium nitrite as an additive. The conversion rate of o-phenylenediamine reached 99.5% at a reaction temperature of 170°C and a pressure of 8MPa, and the selectivity of 1,2-cyclohexane diamine reached 86.3%, and the selectivity of the product could still reach more than 85% after five cycles. Lin Xue et al. used isopropanol as solvent and lithium hydroxide as additive. The experimental results showed that under the conditions of 120℃ and 8MPa, the conversion rate of p-phenylenediamine was 100%, the selectivity of the product 1,4-cyclohexanediamine reached 92%, and the formation of by-product cyclohexylamine was effectively inhibited. Liu Qinglin et al. simultaneously adopted the method of 500℃ activation and alkali treatment of the catalyst, and found that the performance of the treated Ru/C catalyst was significantly improved. Under the conditions of 140℃ and 8MPa, the conversion rate of p-phenylenediamine and the selectivity of 1,4-cyclohexanediamine were 100% and 90%, respectively.

As an important organic chemical and fine chemical intermediate, 1,3-cyclohexylenediamine is widely used in the fields of epoxy resins and composite materials. It is also an important raw material for synthesizing isocyanates. The synthesized alicyclic isocyanates do not contain a benzene ring structure and have relatively stable properties. They can be used to prepare polyurethane products with excellent yellowing resistance. When 1,3-cyclohexylenediamine is used as an alicyclic amine curing agent, it has the advantages of longer application period and lighter color than aliphatic amines. In addition, the molecular structure contains a rigid alicyclic ring, and it has excellent heat resistance, water resistance, chemical resistance and mechanical properties. Meta-phenylenediamine is a highly toxic item. Inhalation of its vapor can cause asthma and other respiratory diseases. Skin absorption leads to blood disorders and affects kidney and liver function. Therefore, it is of great research value to develop a production process for hydrogenating meta-phenylenediamine to 1,3-cyclohexylenediamine. For example, Yang Yanmi and others from Beijing University of Chemical Technology showed excellent catalytic effects using Ru/Al ₂ O ₃ as catalysts. Under the conditions of 5% Ru loading, 130°C reaction temperature, 5MPa reaction pressure, and tetrahydrofuran as solvent, the conversion rate of m-xylenediamine reached 100%, and the selectivity of 1,3-cyclohexylenediamine reached 87.7%. The catalyst modified by LiOH could achieve a 97.9% yield of 1,3-cyclohexylenediamine under the above conditions. Kim et al. used 5wt% Ru/C as catalyst, isopropanol as solvent, and sodium nitrate as additive, and the conversion rate of m-xylenediamine reached 100% and the yield of 1,3-cyclohexylenediamine reached 90.6% under the reaction temperature of 120°C and pressure of 5.4MPa.

At present, the research mainly uses the precious metal Ru loaded on activated carbon or alumina as a catalyst, and adds nitrate or treats the catalyst with alkali to create an alkaline environment to improve the activity of the catalyst and the selectivity for cyclohexanediamine. Precious metal catalysts have high reaction activity, but their high price limits their industrial production and application, so it is of great significance to develop non-precious metal catalysts for the hydrogenation of m-xylylenediamine.

Summary of the invention

In view of the above problems existing in the existing catalytic hydrogenation technology, the purpose of the present invention is to provide a dual non-precious metal catalyst Co-Ni _{/ La2O3} and a preparation method thereof, as well as the application of catalytic selective hydrogenation of m- _{xylylenediamine in a heterogeneous system. The catalyst uses alkaline oxide La2O3 as} a carrier, loads non-precious metals Co and Ni with strong hydrogenation performance, and catalytically hydrogenates m-xylylenediamine without any additives. The preparation method is low in cost, fast in catalytic hydrogenation rate, and easy to separate, and has broad industrial prospects.

To achieve the above object, the present invention adopts the following technical solutions.

One of the purposes of the present invention is to provide a dual non-precious metal catalyst Co-Ni/La ₂ O ₃ , wherein Co and Ni are loaded on a La ₂ O ₃ carrier, wherein the total loading of Co and Ni is 5wt% of the catalyst, and Co:Ni=1:1.

For the method of expressing the loading amount of Co and Ni in the Co-Ni/La ₂ O ₃ catalyst, it is directly abbreviated as 5% in the subsequent content of this article, and its meaning is the same as the 5wt% recorded in this article.

Preferably, in the above catalyst, the total loading of Co and Ni is 5wt% of the catalyst, and the mass ratio of Co to Ni is 1:1.

Another object of the present invention is to provide a method for preparing the dual non-precious metal catalyst Co-Ni/La ₂ O ₃ , the specific steps of which are as follows:

(1) Using La ₂ O ₃ as the carrier, heat and stir on a hot plate to ensure uniform heating;

(2) using nickel nitrate hexahydrate as a nickel source, cobalt nitrate hexahydrate as a cobalt source, and uniformly heated La ₂ O ₃ as a carrier, an unreduced catalyst Co-Ni/La ₂ O ₃ was prepared by an impregnation method;

(3) The unreduced catalyst Co-Ni/La ₂ O ₃ was placed in a tubular furnace in a H ₂ /Ar mixed gas atmosphere for heating reduction, cooled naturally to room temperature, and then introduced into an O ₂ /Ar mixed gas for passivation to obtain a reduced catalyst Co-Ni/La ₂ O ₃ .

Preferably, in step (1), the temperature of the heating plate is 90°C.

Preferably, in step (1) and step (2), the mass ratio of La ₂ O ₃ , cobalt nitrate hexahydrate as the cobalt source, and nickel nitrate hexahydrate is 1:0.1236:0.0951.

Preferably, in step (3), the heating temperature in the tube furnace is 500° C. and the heating time is 2 h.

Preferably, in step (3), the volume fraction of _H2 is 5% and the introduction time is 30 min.

Preferably, in step (3), the volume fraction of _O2 is 0.5% and the introduction time is 30 min.

The method of selectively hydrogenating meta-xylylenediamine using a dual non-noble metal catalyst Co-Ni/La ₂ O ₃ in a heterogeneous system of the present invention comprises the following specific steps:

(1) Select a stainless steel reactor;

(2) Weighing the prepared catalyst Co-Ni/La ₂ O ₃ into a reaction kettle, then weighing m-xylylenediamine and dissolving it in tert-butyl alcohol solvent, and placing the mixed solution into the reaction kettle after ultrasonic dispersion;

(3) After sealing the reactor, flush it with hydrogen at a pressure of 1.0 MPa three times, maintain the hydrogen pressure at 1.0 MPa at room temperature, and check the airtightness of the reactor;

(4) Heat the reactor to 180°C, continue to introduce hydrogen to 8.0 MPa, and maintain the temperature and pressure in the reactor for 3-5 hours;

(5) After the reaction is completed, wait for the reactor to cool to room temperature, open the gas valve, and release hydrogen until the pressure is 0, completing the reaction process.

The present invention also aims to provide the use of a dual non-precious metal catalyst Co-Ni/ _La2O3 in the selective hydrogenation catalysis of m- _{xylylenediamine} in a heterogeneous system. When the conversion rate of m-xylylenediamine is 100%, the selectivity of the catalyst for 1,3-cyclohexylenediamine is greater than 70%.

By adopting the above technology, compared with the prior art, the beneficial effects of the present invention are as follows:

1) The catalyst of the present invention is prepared by an impregnation method, using non-precious metals as the active phase, which greatly reduces the cost of raw materials, and has a simple preparation process, low energy consumption, and is green and environmentally friendly;

2) The catalyst prepared by the present invention has high catalytic performance when the total loading is 5%. The specific conditions are that under the reaction conditions of hydrogen pressure 8MPa, temperature 180°C, reaction time 5h and catalyst 50mg, when the conversion rate of 0.5g of m-phenylenediamine is 100%, the selectivity for 1,3-cyclohexylenediamine reaches more than 70%.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is an X-ray diffraction analysis diagram of catalysts prepared in different embodiments of the present invention;

As can be seen from the figure, compared with the JCPDS standard data of lanthanum oxide, elemental cobalt and elemental nickel, it can be observed that the characteristic peaks of lanthanum oxide are obvious, but no obvious characteristic diffraction peaks of Co and Ni are detected. This is because the Co and Ni loadings in the catalyst are low and the dispersion of the loaded metals is high.

FIG. 2 is a scanning electron microscope image of the catalyst prepared in Example 1 of the present invention.

Detailed ways

The technical solution of the present invention is further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

The present invention uses different ratios of Co and Ni loaded on La ₂ O ₃ as an example, and uses Co and Ni loaded on different oxide supports as a comparative example. The specific preparation process is as follows.

(1) Take 1g of La ₂ O ₃ as the carrier and heat and stir it on a 90℃ hot plate to ensure uniform heating;

(2) 0.1236 g of cobalt nitrate hexahydrate as a cobalt source and 0.0951 g of nickel nitrate hexahydrate as a nickel source were mixed and dissolved in 2 mL of pure water, and an unreduced catalyst Co-Ni/La ₂ O ₃ was prepared by an impregnation method. The cobalt-nickel precursor Co-Ni/La ₂ O ₃ mixed solution was added dropwise to the dried La ₂ O ₃ carrier and stirred evenly until all the mixture was added and dried.

(3) The unreduced catalyst Co-Ni/La ₂ O ₃ was placed in a tubular furnace in a H ₂ /Ar atmosphere for heating reduction. The heating rate of the tubular furnace was 5°C/min, the heating temperature of the tubular furnace was 500°C, the heating time was 2h, the volume fraction of H ₂ in the mixed gas was 5%, and the introduction time was 2h. After naturally cooling to room temperature, an O ₂ /Ar mixed gas was introduced for passivation. The volume fraction of O ₂ was 0.5%, and the introduction time was 30min to obtain Co-Ni/La ₂ O ₃ .

The application process of the catalyst prepared above in the catalytic hydrogenation of m-xylylenediamine was tested, and the performance test steps were as follows:

Performance test: In a 100mL stainless steel reactor, weigh 50mg of the catalyst Co-Ni/La ₂ O ₃ into the reactor, weigh 0.5g of m-phenylenediamine and 30mL of tert-butyl alcohol, dissolve m-phenylenediamine in tert-butyl alcohol, and put the mixed solution into the reactor after ultrasonic dispersion. After sealing the reactor, flush it with hydrogen (1MPa) three times, increase the hydrogen pressure by 1MPa at room temperature, and check the air tightness. After checking the air tightness, adjust the magnetic speed to 500rpm, raise the reactor temperature to 180℃, and then introduce hydrogen until the pressure reaches 8MPa, and start timing. After reacting for 3h, when the reactor is cooled to room temperature, open the gas valve of the reactor and release hydrogen until the pressure reaches 0MPa.

After filtering the reaction solution, use a micro-injection needle to draw 0.4 μL and inject it into the gas chromatograph. The gas chromatograph hydrogen flow rate is set to 40-60 mL/min, the air flow rate is 260-300 mL/min, and the carrier gas flow rate is 2-4 mL/min. The injection temperature is set to 280.0°C, the column furnace temperature is set to 150.0°C, and the FID temperature is set to 280.0°C. Using n-dodecane as the internal standard, the conversion rate of the catalyst to m-phenylenediamine and the selectivity of 1,3-cyclohexanedimethylamine are calculated by gas chromatography.

Example 1: Application test of 5% Co-Ni/La ₂ O ₃ (Co:Ni＝1:1) in catalytic hydrogenation of m-xylylenediamine

The Co-Ni/La ₂ O ₃ catalyst of Example 1, in which the loading amount of Co and Ni is 5% of the catalyst and the ratio of Co to Ni is 1:1, is tested in the catalytic hydrogenation of m-xylylenediamine.

Under the reaction conditions of 8 MPa hydrogen pressure, 180°C temperature, 3 h reaction time, 50 mg catalyst and 0.5 g m-phenylenediamine, the catalyst conversion rate was 72% and the selectivity of 1,3-cyclohexanedimethylamine was 71.3%.

Example 2: Application test of 3% Co-Ni/La ₂ O ₃ (Co:Ni＝1:1) in catalytic hydrogenation of m-xylylenediamine

The Co-Ni/La ₂ O ₃ catalyst of Example 2, in which the loading amount of Co and Ni is 3% of the catalyst and the ratio of Co to Ni is 1:1, is tested in the catalytic hydrogenation of m-xylylenediamine.

Under the reaction conditions of 8 MPa hydrogen pressure, 180°C temperature, 3 h reaction time, 50 mg catalyst and 0.5 g m-phenylenediamine, the catalyst conversion rate was 32.7% and the selectivity of 1,3-cyclohexanedimethylamine was 28.6%.

Example 3: Application test of 7% Co-Ni/La ₂ O ₃ (Co:Ni＝1:1) in catalytic hydrogenation of m-xylylenediamine

The Co-Ni/La ₂ O ₃ catalyst of Example 3, in which the loading amount of Co and Ni is 7% of the catalyst and the ratio of Co to Ni is 1:1, was tested in the catalytic hydrogenation of m-xylylenediamine:

Under the reaction conditions of 8 MPa hydrogen pressure, 180°C temperature, 3 h reaction time, 50 mg catalyst and 0.5 g m-phenylenediamine, the catalyst conversion rate was 99.9% and the selectivity of 1,3-cyclohexanedimethylamine was 32.6%.

Example 4: Application test of 5% Co-Ni/La ₂ O ₃ (Co:Ni＝1:0.5) in catalytic hydrogenation of m-xylylenediamine

The Co-Ni/La ₂ O ₃ catalyst of Example 4, in which the loading amount of Co and Ni is 5% of the catalyst and the ratio of Co to Ni is 1:0.5, is tested in the catalytic hydrogenation of m-xylylenediamine.

Under the reaction conditions of 8 MPa hydrogen pressure, 180°C temperature, 3 h reaction time, 50 mg catalyst and 0.5 g m-phenylenediamine, the catalyst conversion rate was 99.9% and the selectivity of 1,3-cyclohexanedimethylamine was 32.6%.

Example 5: Application test of 5% Co-Ni/La ₂ O ₃ (Co:Ni＝1:2) in catalytic hydrogenation of m-xylylenediamine

The Co-Ni/La ₂ O ₃ catalyst of Example 5, in which the loading amount of Co and Ni is 5% of the catalyst and the ratio of Co to Ni is 1:2, is tested in the catalytic hydrogenation of m-xylylenediamine.

Under the reaction conditions of 8 MPa hydrogen pressure, 180°C temperature, 3 h reaction time, 50 mg catalyst and 0.5 g m-xylenediamine, the catalyst conversion rate was 90.8% and the selectivity of 1,3-cyclohexylenediamine was 51.6%.

Comparative Example 1: Application test of 5% Co-Ni/TiO ₂ (Co:Ni＝1:1) in catalytic hydrogenation of m-xylylenediamine

The rutile TiO ₂ catalyst Co-Ni/TiO ₂ of Comparative Example 1, with a loading amount of 5% of metal Co and Ni, was tested in the catalytic hydrogenation of m-xylylenediamine.

Under the reaction conditions of hydrogen pressure of 8 MPa, temperature of 180° C., reaction time of 3 h, catalyst of 50 mg, and p-chloronitrobenzene of 0.5 g, the catalyst conversion rate was 24.8%, and the selectivity of 1,3-cyclohexyldimethylamine was 10.2%.

Comparative Example 2: Application test of 5% Co-Ni/CeO ₂ (Co:Ni＝1:1) in catalytic hydrogenation of m-xylylenediamine

The CeO ₂ -loaded Co-Ni/CeO ₂ catalyst of Comparative Example 2, in which the metal Co and Ni loading amounts were 5% and Co:Ni=1:1, was tested in the catalytic hydrogenation of m-xylylenediamine.

Under the reaction conditions of hydrogen pressure of 8 MPa, temperature of 180° C., reaction time of 3 h, catalyst of 50 mg, and m-xylylenediamine of 0.5 g, the catalyst conversion rate was 99.9% and the selectivity of m-xylylenediamine was 31.6%.

Comparative Example 3: Application test of 5% Co-Ni/SiO ₂ (Co:Ni＝1:1) in catalytic hydrogenation of m-xylylenediamine

The _SiO2- loaded Co-Ni/ _CeO2 catalyst of Comparative Example 3, in which the metal Co and Ni loading amounts were 5% and Co:Ni=1:1, was tested in the catalytic hydrogenation of m-xylylenediamine.

Under the reaction conditions of hydrogen pressure of 8 MPa, temperature of 180° C., reaction time of 3 h, catalyst of 50 mg, and m-xylylenediamine of 0.5 g, the catalyst conversion rate was 12.6% and the selectivity of m-xylylenediamine was 9.5%.

Comparative Example 4: Application test of 5% Co-Ni/MgO (Co:Ni=1:1) in catalytic hydrogenation of m-xylylenediamine

The _MgO2- loaded Co-Ni/ _MgO2 catalyst of Comparative Example 4, in which the metal Co and Ni loading amounts were 5% and Co:Ni=1:1, was tested in the catalytic hydrogenation of m-xylylenediamine.

Under the reaction conditions of hydrogen pressure of 8 MPa, temperature of 180° C., reaction time of 3 h, catalyst of 50 mg, and m-xylylenediamine of 0.5 g, the catalyst conversion rate was 78.3% and the selectivity of m-xylylenediamine was 26.7%.

Comparative Example 5: Application test of 5% Co/La ₂ O ₃ in catalytic hydrogenation of m-phenylenediamine

The Co-loaded Co/La ₂ O ₃ catalyst of Comparative Example 5, wherein the Co loading amount is 5%, is tested in the catalytic hydrogenation of m-xylylenediamine.

Under the reaction conditions of 8 MPa hydrogen pressure, 180° C., 3 h reaction time, 50 mg catalyst and 0.5 g m-xylylenediamine, the catalyst conversion rate was 20.5% and the m-xylylenediamine selectivity was 27.7%.

Comparative Example 6: Application test of 5% Ni/La ₂ O ₃ in catalytic hydrogenation of m-phenylenediamine

The catalyst Ni/La ₂ O ₃ in which La ₂ O ₃ loaded with metal Ni in Comparative Example 6, wherein the loading amount of Ni was 5%, was tested in the catalytic hydrogenation of m-xylylenediamine.

Under the reaction conditions of hydrogen pressure of 8 MPa, temperature of 180° C., reaction time of 3 h, catalyst of 50 mg, and m-xylylenediamine of 0.5 g, the catalyst conversion rate was 99.9% and the selectivity of m-xylylenediamine was 45.4%.

The effects of different carriers on catalytic performance were studied by comparative studies, the performance and parameters of the products were obtained by testing, and the optimal performance of the products was determined by analysis. Table 1 shows the catalyst products obtained by different carrier conditions, the results obtained by testing their performance, and comparative cases.

Table 1: Effect of different supported catalysts on hydrogenation of m-phenylenediamine

Reaction conditions: catalyst loading of 5%, Co:Ni=1:1, catalyst 50 mg, m-xylylenediamine 0.5 g, tert-butanol 30 mL, temperature 180° C., hydrogen pressure 8 MPa, reaction time 3 h, catalyst reducing atmosphere 5% H ₂ /Ar.

It can be seen from Table 1 that different supports have a great influence on the activity. Using La ₂ O ₃ as a support can significantly improve the activity of the catalyst and the selectivity for m-phenylenediamine.

By studying the influence of different loading amounts of elements on the catalytic performance of the catalyst, the performance and parameters of the product are detected, and the optimal performance of the product is determined by analysis. Table 2 shows the results and comparative cases obtained by testing the performance of catalyst products with different loading amounts of elements.

Table 2: Effect of different metal loadings on catalyst activity

Reaction conditions: Co:Ni=1:1, catalyst 50 mg, m-phenylenediamine 0.5 g, tert-butanol 30 mL, temperature 180°C, hydrogen pressure 8 MPa, reaction time 3 h.

It can be seen from Table 2 that when the metal loading is 7%, although the conversion rate of m-xylenediamine is high, a large amount of by-products are generated, and the selectivity of 1,3-cyclohexanedimethylamine is low. Therefore, 5% loading is taken as the optimal loading.

By studying the effect of the loading ratio of Co and Ni on the catalytic performance of the catalyst, the performance and parameters of the product are detected, and the optimal performance of the product is determined by analysis. Table 3 shows the performance results of the catalyst products with different loading ratios of Co and Ni.

Table 3: Effect of different Co:Ni ratios on catalyst activity

Reaction conditions: catalyst loading of 5%, catalyst 50 mg, m-phenylenediamine 0.5 g, tert-butanol 30 mL, temperature 180° C., hydrogen pressure 8 MPa, reaction time 3 h.

It can be seen from Table 3 that when Co:Ni=1:1, the yield of 1,3-cyclohexanedimethylamine is higher.

By studying the effect of the catalytic reaction time on the catalytic performance of the catalyst during the catalytic reaction of meta-xylene, the optimal performance of the product is determined by analysis. Table 4 shows the effect of different catalytic reaction times on the performance of the catalyst, and the performance results are tested.

Table 4: Effect of reaction time on catalytic activity

Reaction conditions: 50 mg of catalyst 5% Co-Ni/La ₂ O ₃ (Co:Ni=1:1), 0.5 g of m-xylylenediamine, 30 mL of tert-butanol, 180° C., 8 MPa of hydrogen pressure, and 5% H ₂ /Ar reducing atmosphere.

It can be seen from Table 4 that as the reaction time increases, m-phenylenediamine is completely converted in 5 h, and the selectivity of 1,3-cyclohexanedimethylamine is >70% when the conversion is complete.

By studying the effect of the volume fraction of hydrogen in the reducing atmosphere on the catalytic reaction process during the catalytic reaction of meta-xylene, the optimal reaction performance of the product was determined by analysis. Table 5 shows the effect of different reducing atmospheres on the catalytic reaction.

Table 5: Effect of different reducing atmospheres on catalyst activity

Reaction conditions: catalyst loading of 5%, Co:Ni=1:1, catalyst 50 mg, m-phenylenediamine 0.5 g, tert-butanol 30 mL, temperature 180° C., hydrogen pressure 8 MPa, reaction time 3 h.

It can be seen from Table 5 that the reducing atmosphere of 5% H ₂ /Ar has a higher conversion rate of m-xylylenediamine and selectivity of 1,3-cyclohexylenediamine, which may be attributed to the milder reducing atmosphere that makes the catalyst particle size smaller after reduction.

The above description is only part of the embodiments of the present invention and is not intended to limit the present invention. All equivalent changes and modifications made according to the content of the present invention are within the protection scope of the present invention.

Claims (10)

1. A dual non-precious metal catalyst Co-Ni/ _La2O3 , characterized in _that Co and Ni are loaded on _La2O3 , wherein the total loading of Co and Ni is 3-7wt% of the catalyst, and Co:Ni=1: _0.5-2 . 2 . The dual non-precious metal catalyst Co—Ni/La ₂ O ₃ according to claim 1 , characterized in that the total loading of Co and Ni is 5 wt % of the catalyst, and the mass ratio of Co to Ni is 1:1. 3. A method for preparing the dual non-precious metal catalyst Co-Ni/La ₂ O ₃ as described in any one of claims 1 to 2, characterized in that the specific steps are as follows: (1) Using La ₂ O ₃ as the carrier, heat and stir on a hot plate to ensure uniform heating; (2) Cobalt nitrate hexahydrate (0.1236 g) as a cobalt source and nickel nitrate hexahydrate (0.0951 g) as a nickel source were mixed and dissolved in 2 mL of pure water, and an unreduced catalyst Co-Ni/La ₂ O ₃ was prepared by an impregnation method. The cobalt-nickel precursor mixture was added dropwise to the dried support and stirred evenly until all the mixture was added and dried. (3) The unreduced catalyst Co-Ni/La ₂ O ₃ was placed in a tube furnace in a H ₂ /Ar atmosphere for heating reduction, cooled naturally to room temperature, and then introduced with a mixed gas of O ₂ /Ar for passivation to obtain Co-Ni/La ₂ O ₃ . 4. The method for preparing _the dual non-precious metal catalyst Co-Ni/ _La2O3 according to claim 3, characterized in that in the step (1), the temperature of the heating plate is 90°C. 5. The method for preparing the dual non-precious metal catalyst Co-Ni/ _La2O3 according to claim ₃ , characterized in that in the step (1) and the step (2), the mass ratio of _La2O3 , _cobalt nitrate hexahydrate as the cobalt source, and nickel nitrate hexahydrate is 1:0.1236:0.0951. 6. The method for preparing the dual non-precious metal catalyst Co-Ni/ _La2O3 according to claim ₃ , characterized in that in the step (3), the heating rate of the tubular furnace is 5°C/min. 7. The method for preparing the catalyst Co-Ni/ _La2O3 according to claim ₃ , characterized in that in the step (3), the reduction temperature of the tubular furnace is 500°C and the heating time is 2 hours. 8. The method for preparing the dual non-precious metal catalyst Co-Ni/ _La2O3 according to claim ₃ , characterized in that in the step (3), the volume fraction of _H2 in the mixed gas is 5%, and the introduction time is 2h. 9. The method for preparing the dual non-precious metal catalyst Co-Ni/ _La2O3 according to claim ₃ , characterized in that in the step (3), the volume fraction of _O2 in the mixed gas is 0.5%, and the introduction time is 30 minutes. 10. Use of the dual non-precious metal catalyst Co-Ni/ _La2O3 as claimed in any one of claims 1 to 2 for catalyzing the selective hydrogenation of m- _{xylylenediamine} in a heterogeneous system, characterized in that the selectivity of the catalyst for 1,3-cyclohexylenediamine is greater than 70% when the conversion rate of m-xylylenediamine is 100%.