A method for the continuous production of m-xylylenediamine

Abstract

The application relates to a method for continuously producing m-xylylenediamine, belonging to the technical field of organic synthesis, and comprising the following steps: (1) mixing m-xylylenedinitrile, toluene and liquid ammonia in a mass ratio of 1:(3-5):(13-17) to form a reaction mixture under a nitrogen atmosphere; (2) heating the inside of a reaction bed containing a catalyst to 90-95 DEG C, continuously feeding hydrogen into the reaction bed, feeding the reaction mixture into the reaction bed after the pressure of the reaction bed is stabilized, and performing a catalytic hydrogenation reaction to generate a reaction product; (3) performing gas-liquid separation on the reaction product, removing liquid ammonia from the liquid-phase product through an ammonia evaporation process, and then separating toluene and m-xylylenediamine through a rectification process to obtain m-xylylenediamine. The application uses m-xylylenedinitrile and hydrogen as raw materials, liquid ammonia and toluene as reaction solvents, and performs an exothermic reaction under the catalysis of a catalyst and by heating to 90-95 DEG C, so that m-xylylenediamine is generated, and the reaction yield is greater than 99%.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, and specifically relates to a method for the continuous production of m-phenylenediamine. Background Technology

[0002] m-Phenylenediamine is mainly used to manufacture high-performance epoxy resin curing agents that are heat-resistant, non-toxic, suitable for underwater construction, and rapidly cured by heating. It is a raw material for polyurethane resins and synthetic functional epoxy resins. At the same time, it is also widely used in rubber products, photosensitive plastics, pesticides, coatings, nylon products, fiber finishing agents, rust inhibitors, chelating agents, lubricants, paper processing and other fields.

[0003] Currently, m-phenylenediamine is mainly produced using the catalytic hydrogenation process of isophthalonitrile. Domestic industrial production of m-phenylenediamine still primarily relies on batch reactors, resulting in small-scale production, fine catalyst particles that are easily pulverized, poor separation efficiency, and problems such as high production costs, poor safety, and low automation. Furthermore, batch reactor reactions typically employ magnetic or mechanical stirring, making it difficult to ensure a sufficient hydrogen supply to the catalyst surface, leading to an excessive amount of imine intermediates in the reaction solution and the generation of too many byproducts. Therefore, a continuous production process and a suitable, highly efficient catalyst are needed to achieve efficient production of isophthalonitrile. Summary of the Invention

[0004] In view of the above situation and to overcome at least some of the defects of the prior art, the present invention provides a method for continuous production of m-phenylenediamine.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for continuous production of m-phenylenediamine includes the following steps:

[0007] (1) Under a nitrogen atmosphere, isophthalonitrile, toluene and liquid ammonia are mixed in a mass ratio of 1:(3-5):(13-17) to form a reaction mixture;

[0008] (2) The reaction bed containing the catalyst is heated to 90-95°C, and hydrogen is continuously introduced into the reaction bed. After the pressure of the reaction bed is stabilized, the reaction mixture is introduced to carry out the catalytic hydrogenation reaction and generate the reaction product.

[0009] (3) The reaction products are separated into gas and liquid phases. The liquid phase products are removed by ammonia stripping and then separated into toluene and m-phenylenediamine by distillation to obtain m-phenylenediamine.

[0010] In some embodiments of the present invention, in step (2), the flow rate of the reaction mixture is 9-10 kg / h; the flow rate of the hydrogen gas is 170-180 L / h, and the pressure is 8-10 MPa.

[0011] In some embodiments of the present invention, in step (2), the bulk density of the catalyst is 0.3-0.4 g / mL and the loading is 1.0-1.2 kg / (kg·h).

[0012] In some embodiments of the present invention, step (3) includes the following specific steps in the ammonia stripping process:

[0013] The liquid product is passed into an ammonia stripping tower and heated to 70-80°C for ammonia stripping. The resulting liquid phase is the ammonia stripping product.

[0014] In some embodiments of the present invention, step (3) includes the following specific steps of the distillation process:

[0015] The ammonia stripping product is fed into a first distillation column and heated to 115-120°C for primary distillation. Then, the bottom product is fed into a second distillation column and heated to 120-150°C for secondary distillation.

[0016] In some embodiments of the present invention, in step (2), the catalyst includes a support and an active component supported on the support, wherein the support is porous carbon, the porous carbon is porous carbon obtained by polymerization and carbonization of carboxymethyl chitosan and glucosamine hydrochloride, and the active component includes transition metals, noble metals and rare earth metals.

[0017] The transition metal is selected from one or more of Ni, Co, and Cu; the noble metal is selected from one or more of Ru, Pd, Ir, and Pt; and the rare earth metal is selected from one of Eu and Yb.

[0018] In some embodiments of the present invention, the mass ratio of transition metal, noble metal and rare earth metal in the active component is 10:(1-5):(1-5).

[0019] In some embodiments of the present invention, the loading of the active component is 5-10 wt%.

[0020] In some embodiments of the present invention, the method for preparing the catalyst includes the following steps:

[0021] Carboxymethyl chitosan and glucosamine hydrochloride were dissolved in deionized water, and hydrothermal polymerization was carried out at 130-160℃ for 20-25 hours. After cooling, the precursor was obtained.

[0022] After drying the precursor, it is placed in a quartz tube and calcined at 700-800℃ for 2-6 hours under an inert atmosphere. After cooling, porous carbon is obtained.

[0023] Rare earth metals and porous carbon are added to a reaction vessel. Liquid ammonia is added under an inert atmosphere, and the mixture is heated to 40-50°C and stirred for 4-8 hours. After washing and drying, the mixture is calcined at 450-500°C for 1-3 hours under an inert atmosphere and then cooled to obtain rare earth porous carbon.

[0024] After mixing the transition metal salt solution and the noble metal salt solution, rare earth porous carbon and NaBH4 solution were added, heated to 40-50℃, stirred for 2-4 hours, washed, and dried to obtain the catalyst.

[0025] In some embodiments of the present invention, the mass ratio of carboxymethyl chitosan to glucosamine hydrochloride is 2:(2-3).

[0026] The beneficial effects achieved by this invention are as follows:

[0027] This invention employs a catalytic hydrogenation process for isophthalonitrile, using isophthalonitrile and hydrogen as raw materials, and liquid ammonia and toluene as reaction solvents. Under the catalysis of a catalyst, the mixture is heated to 90-95°C for an exothermic reaction, continuously producing m-phenylenediamine with a yield greater than 99%. Simultaneously, liquid ammonia is removed through an ammonia stripping process, and toluene and m-phenylenediamine are separated through a distillation process, yielding high-purity m-phenylenediamine. The separated liquid ammonia and toluene can then be further used to produce m-phenylenediamine, significantly reducing production costs. Attached Figure Description

[0028] Figure 1 This is a flowchart of the preparation method of m-phenylenediamine according to an embodiment of the present invention.

[0029] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0032] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0033] Reference Figure 1 To address the shortcomings of the prior art mentioned in the background section, a method for continuous production of m-phenylenediamine includes the following steps:

[0034] (1) Under a nitrogen atmosphere, isophthalonitrile, toluene and liquid ammonia are mixed in a mass ratio of 1:(3-5):(13-17) to form a reaction mixture;

[0035] (2) The reaction bed containing the catalyst is heated to 90-95°C, and hydrogen is continuously introduced into the reaction bed. After the pressure of the reaction bed is stabilized, the reaction mixture is introduced to carry out the catalytic hydrogenation reaction and generate the reaction product.

[0036] (3) The reaction products are separated into gas and liquid phases. The liquid phase products are removed by ammonia stripping and then separated into toluene and m-phenylenediamine by distillation to obtain m-phenylenediamine.

[0037] First, the preparation method of m-phenylenediamine employs a catalytic hydrogenation process using isophthalonitrile. In this method, isophthalonitrile and hydrogen are the raw materials, while liquid ammonia and toluene are the reaction solvents. Then, under the catalysis of the catalyst, the mixture is heated to 90-95℃ for an exothermic reaction, producing m-phenylenediamine with a yield greater than 99%. The reaction equation is as follows:

[0038]

[0039] In the formula, cat represents the catalyst and PhMe represents toluene.

[0040] Secondly, in step (1), insufficient addition of toluene will lead to incomplete dissolution of isophthalonitrile, reducing the reaction yield and even clogging the reactor. Excessive addition of toluene will dilute the isophthalonitrile, resulting in a decrease in the reaction rate. Liquid ammonia not only acts as a solvent to promote the dissolution and diffusion of hydrogen and isophthalonitrile, but its strong alkalinity also protonates the imine intermediate, blocking the polycondensation pathway and thus reducing the content of reaction byproducts. Insufficient addition of liquid ammonia will lead to an increase in the byproduct imine intermediate, generating a large amount of dimers and reducing the reaction yield. Excessive addition of liquid ammonia will lead to increased consumption and excessive costs due to the evaporation and recovery of excess liquid ammonia. In step (2), excessively high temperature of the reaction bed will lead to an increase in side reactions, product dimerization, and a decrease in reaction yield. Excessively low temperature of the reaction bed will lead to a low reaction conversion rate, a large amount of reaction intermediates will be retained, and the reaction yield will also decrease.

[0041] Finally, in step (3), the gas-liquid separation can remove excess hydrogen, which can be recovered by a hydrogen compressor. The remaining liquid phase consists of liquid ammonia, toluene, and m-phenylenediamine. The liquid ammonia is then removed by ammonia stripping, and toluene and m-phenylenediamine are separated by distillation to produce high-purity m-phenylenediamine. Furthermore, the separated liquid ammonia and toluene can be used to further produce m-phenylenediamine, greatly reducing production costs.

[0042] In some embodiments, in step (2), the flow rate of the reaction mixture is 9-10 kg / h; the flow rate of hydrogen is 170-180 L / h; and the pressure is 8-10 MPa. If the flow rate of the reaction mixture is too high, the reaction residence time is insufficient, the reaction conversion rate decreases, and the resulting heat accumulation can trigger side reactions. If the flow rate of the reaction mixture is too low, production efficiency decreases, the heat of reaction cannot be released stably, leading to temperature fluctuations and affecting catalyst activity and product purity. If the flow rate of hydrogen is too high, hydrogen is wasted, increasing the load on the circulation system. If the flow rate of hydrogen is too low, the hydrogen partial pressure is insufficient, leading to incomplete reaction (generating an imine intermediate), and a decrease in conversion rate and product purity. If the pressure is too high, the energy consumption and cost of the reaction are too high; if the pressure is too low, the hydrogen solubility is insufficient, and the reaction rate decreases.

[0043] In some embodiments, in step (2), the bulk density of the catalyst is 0.3-0.4 g / mL, and the loading is 1.0-1.2 kg / (kg·h). It is understood that the bulk density of the catalyst refers to the density of the catalyst in its packed state in the reaction bed. The smaller the bulk density, the larger the gaps between catalysts; the larger the bulk density, the smaller the gaps between catalysts. The catalyst loading represents the amount of reaction mixture processed per unit mass of catalyst per hour. If the catalyst bulk density is too high, the fluid distribution in the reaction bed will be uneven, forming dead zones or local overheating, leading to an aggravation of side reactions; if the catalyst bulk density is too low, the effective catalytic active sites will decrease, and the reaction rate will decrease. If the catalyst loading is too high, the catalyst lifespan will be too short; if the catalyst loading is too low, the reaction will be incomplete, and the yield will decrease.

[0044] In some embodiments, step (3) of the ammonia stripping process includes: passing the liquid product into an ammonia stripping tower and heating it to 70-80°C for ammonia stripping, the resulting liquid phase being the ammonia stripping product. The ammonia stripping process can remove residual liquid ammonia from the liquid product, improving product purity. At the same time, liquid ammonia acts as a solvent in the hydrogenation reaction, and the ammonia stripping process can recover more than 90% of the liquid ammonia, significantly reducing raw material consumption and lowering costs.

[0045] In some embodiments, step (3) of the distillation process includes: feeding the ammonia stripping product into a first distillation column, heating it to 115-120°C for primary distillation, and then feeding the bottom product into a second distillation column, heating it to 120-150°C for secondary distillation. The first distillation column is mainly used to remove toluene. At 115-120°C, toluene preferentially vaporizes and is recovered by condensation at the top of the column. After recovery, it can be reused, thereby reducing solvent consumption. The second distillation column can remove the toluene and other impurities remaining in the first distillation column, thereby further improving the purity of the product.

[0046] In some embodiments, in step (2), the catalyst includes a support and an active component supported on the support. The support is porous carbon, which is obtained by polymerization and carbonization of carboxymethyl chitosan and glucosamine hydrochloride. The active component includes transition metals, noble metals, and rare earth metals. Carboxymethyl chitosan and glucosamine hydrochloride form a three-dimensional network structure through polymerization, and after carbonization and decomposition, they can form porous carbon with a high specific surface area, providing abundant active sites. At the same time, the nitrogen atoms introduced into the porous carbon can improve the active component loading capacity of the porous carbon. Among the active components, the interaction between transition metals and noble metals can accelerate the hydrogenation step of nitrile groups and reduce the reaction energy barrier. Rare earth metals can enhance the adsorption capacity of porous carbon for hydrogen and nitrile groups. The interaction of the three can improve the catalyst activity, selectivity, and lifetime. Among them, the transition metals are selected from one or more of Ni, Co, and Cu, the noble metals are selected from one or more of Ru, Pd, Ir, and Pt, and the rare earth metals are selected from Eu and Yb.

[0047] In some embodiments, the mass ratio of transition metals, noble metals, and rare earth metals in the active component is 10:(1-5):(1-5). Increasing the proportion of noble metals in the active component leads to a significant increase in cost and a higher risk of excessive hydrogenation side reactions; too low a proportion results in insufficient hydrogen dissociation efficiency and slower reaction kinetics. Conversely, an excessively high proportion of rare earth metals causes rare earth oxides to cover active sites, hindering reactant diffusion and potentially introducing excessive alkalinity leading to side reactions; too low a proportion results in insufficient electronic regulation and decreased catalyst stability.

[0048] In some embodiments, the loading of the active component is 5-10 wt%. Within this loading range, the metal nanoparticles can achieve high dispersion on the porous carbon support. When the loading is greater than 10 wt%, the metal nanoparticles will block the micropores of the porous carbon, increasing the mass transfer resistance.

[0049] In some embodiments, the catalyst preparation method includes the following steps: dissolving carboxymethyl chitosan and glucosamine hydrochloride in deionized water, heating to 130-160℃ for hydrothermal polymerization for 20-25 h, and cooling to obtain a precursor; drying the precursor, placing it in a quartz tube, and calcining it at 700-800℃ for 2-6 h under an inert atmosphere, and cooling to obtain porous carbon; adding rare earth metals and porous carbon to a reactor, adding liquid ammonia under an inert atmosphere, heating to 40-50℃, stirring for 4-8 h, washing and drying, and calcining at 450-500℃ for 1-3 h under an inert atmosphere, and cooling to obtain rare earth porous carbon; mixing a transition metal salt solution and a noble metal salt solution, adding rare earth porous carbon and NaBH4 solution, heating to 40-50℃, stirring for 2-4 h, washing and drying to obtain the catalyst. Rare earth metals are dissolved in liquid ammonia and form coordination bonds with functional groups on the surface of porous carbon. After calcination, a rare earth metal-porous carbon composite structure can be formed. NaBH4 can reduce transition metal salts and noble metal salts, thereby forming bimetallic nanoparticles on porous carbon.

[0050] In some embodiments, the mass ratio of carboxymethyl chitosan to glucosamine hydrochloride is 2:(2-3). The carboxyl groups of carboxymethyl chitosan and the amino groups of glucosamine hydrochloride can form a three-dimensional network through electrostatic interaction, and further dehydrate and condense under high temperature hydrothermal conditions to form amide bonds. The mass ratio of 2:(2-3) can ensure sufficient cross-linking points and avoid insufficient cross-linking leading to a loose carbon skeleton.

[0051] The present invention will be further described below by way of specific embodiments.

[0052] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; unless otherwise specified, the experimental materials used in the following embodiments are all purchased from commercial channels.

[0053] Example 1

[0054] Carboxymethyl chitosan and glucosamine hydrochloride in a 1:1 mass ratio were dissolved in deionized water and subjected to hydrothermal polymerization at 130°C for 20 h. After cooling, a precursor was obtained. The precursor was dried and placed in a quartz tube, then calcined at 700°C for 2 h under an inert atmosphere. After cooling, porous carbon was obtained. Rare earth metals Eu and Yb and porous carbon were added to a reactor. Liquid ammonia was added under an inert atmosphere to fully dissolve the rare earth metals. The mixture was heated to 40°C and stirred for 4 h. After washing and drying, the mixture was calcined at 450°C for 1 h under an inert atmosphere. After cooling, rare earth porous carbon was obtained. A transition metal salt solution and a noble metal salt solution were mixed, and rare earth porous carbon and NaBH4 solution were added. The mixture was heated to 40°C and stirred for 2 h. After washing and drying, a catalyst was obtained. The loading of the active component in the catalyst was 5 wt%, and the mass ratio of transition metal, noble metal and rare earth metal in the active component was 10:1:1.

[0055] Under a nitrogen atmosphere, isophenylenedionitrile, toluene, and liquid ammonia are mixed in a mass ratio of 1:3:13 to form a reaction mixture. The reaction bed containing the catalyst is heated to 90°C, and hydrogen is continuously introduced into the reaction bed at a flow rate of 170 L / h and a pressure of 8 MPa. After the pressure of the reaction bed stabilizes, the reaction mixture is introduced at a flow rate of 9 kg / h to carry out a catalytic hydrogenation reaction. The catalyst has a bulk density of 0.3 g / mL and a loading of 1.0 kg / (kg·h). The reaction products are subjected to gas-liquid separation. The liquid product is fed into an ammonia stripping column and heated to 70°C for ammonia stripping. The ammonia stripped product is fed into a first distillation column and heated to 115°C for primary distillation. The bottom product is then fed into a second distillation column and heated to 120°C for secondary distillation to obtain m-phenylenediamine.

[0056] Example 2

[0057] Carboxymethyl chitosan and glucosamine hydrochloride in a mass ratio of 2:3 were dissolved in deionized water and subjected to hydrothermal polymerization at 160°C for 25 h. After cooling, a precursor was obtained. The precursor was dried and placed in a quartz tube, then calcined at 800°C for 6 h under an inert atmosphere. After cooling, porous carbon was obtained. Rare earth metals Eu and Yb and porous carbon were added to a reactor. Liquid ammonia was added under an inert atmosphere to fully dissolve the rare earth metals. The mixture was heated to 50°C and stirred for 8 h. After washing and drying, the mixture was calcined at 500°C for 3 h under an inert atmosphere. After cooling, rare earth porous carbon was obtained. A transition metal salt solution and a noble metal salt solution were mixed, and rare earth porous carbon and NaBH4 solution were added. The mixture was heated to 50°C and stirred for 4 h. After washing and drying, a catalyst was obtained. The loading of the active component in the catalyst was 10 wt%, and the mass ratio of transition metal, noble metal and rare earth metal in the active component was 10:5:5.

[0058] Under a nitrogen atmosphere, isophthalonitrile, toluene, and liquid ammonia are mixed in a mass ratio of 1:5:17 to form a reaction mixture. The reaction bed containing the catalyst is heated to 95°C, and hydrogen is continuously introduced into the reaction bed at a flow rate of 180 L / h and a pressure of 10 MPa. After the pressure of the reaction bed stabilizes, the reaction mixture is introduced at a flow rate of 10 kg / h to carry out a catalytic hydrogenation reaction. The catalyst has a bulk density of 0.4 g / mL and a loading of 1.2 kg / (kg·h). The reaction products are subjected to gas-liquid separation. The liquid product is fed into an ammonia stripping column and heated to 80°C for ammonia stripping. The ammonia stripped product is fed into a first distillation column and heated to 120°C for primary distillation. The bottom product is then fed into a second distillation column and heated to 150°C for secondary distillation to obtain m-phenylenediamine.

[0059] Example 3

[0060] Consistent with Example 1, except that the loading of the active component in the catalyst is 6 wt%, and the mass ratio of transition metal, noble metal and rare earth metal in the active component is 10:2:2.

[0061] Example 4

[0062] Consistent with Example 1, except that the loading of the active component in the catalyst is 7 wt%, and the mass ratio of transition metal, noble metal and rare earth metal in the active component is 10:3:3.

[0063] Example 5

[0064] Consistent with Example 1, except that the loading of the active component in the catalyst is 8 wt%, and the mass ratio of transition metal, noble metal and rare earth metal in the active component is 10:4:4.

[0065] Comparative Example 1

[0066] Consistent with Example 1, except that Raney nickel is used as the catalyst.

[0067] The catalytic hydrogenation processes of Examples 1-5 and Comparative Example 1 were analyzed, and the reaction results are shown in Table 1.

[0068] Table 1:

[0069]

[0070] In Table 1, conversion rate indicates the proportion of reactants consumed. For example, the conversion rate in Example 1 is 99.5%, indicating that 99.5% of the isophthalonitrile reacted. Selectivity indicates the efficiency with which the reactants are converted into the target product. For example, the selectivity in Example 1 is 99.6%, indicating that 99.6% of the isophthalonitrile consumed in the reaction was converted into m-phenylenediamine. In summary, Table 1 shows that the method of this invention can achieve a yield of over 99% for preparing m-phenylenediamine, and the catalyst prepared by this invention has better performance than that of Comparative Example 1.

[0071] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0072] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A method for continuous production of m-xylylenediamine, characterized in that, The method comprises the following steps: (1) mixing isophthalonitrile, toluene and liquid ammonia in a mass ratio of 1:(3-5):(13-17) to form a reaction mixture under a nitrogen atmosphere; (2) heating the inside of a reaction bed containing a catalyst to 90-95 DEG C, continuously feeding hydrogen into the reaction bed, and feeding the reaction mixture into the reaction bed after the pressure of the reaction bed is stabilized to perform a catalytic hydrogenation reaction to generate a reaction product; (3) performing gas-liquid separation on the reaction product, removing liquid ammonia from the liquid-phase product through an ammonia distillation process, and then separating toluene and m-xylylenediamine through a rectification process to obtain m-xylylenediamine; In step (2), the catalyst comprises a carrier and an active component supported on the carrier, the carrier is porous carbon, the porous carbon is obtained by polymerization and carbonization of carboxymethyl chitosan and glucosamine hydrochloride, and the active component comprises transition metals, noble metals and rare earth metals; the transition metals are selected from one or more of Ni, Co and Cu, the noble metals are selected from one or more of Ru, Pd, Ir and Pt, and the rare earth metals comprise Eu and Yb. The catalyst is prepared by the following method: carboxymethyl chitosan and glucosamine hydrochloride are dissolved in deionized water, heated to 130-160 DEG C for hydrothermal polymerization for 20-25 h, and then cooled to obtain a precursor; the precursor is dried, placed in a quartz tube, heated to 700-800 DEG C for calcination under an inert atmosphere for 2-6 h, and then cooled to obtain the porous carbon; rare earth metals Eu and Yb and the porous carbon are added to a reaction kettle, liquid ammonia is added under an inert atmosphere, heated to 40-50 DEG C, and stirred for 4-8 h; after washing and drying, the rare earth porous carbon is obtained by calcination under an inert atmosphere at 450-500 DEG C for 1-3 h and then cooling; the transition metal salt solution and the noble metal salt solution are mixed, the rare earth porous carbon and a NaBH4 solution are added, heated to 40-50 DEG C, and stirred for 2-4 h; after washing and drying, the catalyst is obtained.

2. The method of claim 1, wherein, In step (2), the flow rate of the reaction mixture is 9-10 kg / h; the flow rate of the hydrogen is 170-180 L / h, and the pressure is 8-10 MPa.

3. The method of claim 1, wherein, In step (2), the bulk density of the catalyst is 0.3-0.4 g / mL, and the load is 1.0-1.2 kg / (kg·h).

4. The method of claim 1, wherein, In step (3), the specific steps of the ammonia distillation process include: feeding the liquid-phase product into an ammonia distillation tower, heating to 70-80 DEG C for ammonia distillation, and the obtained liquid phase is the ammonia distillation product.

5. The method of claim 1, wherein, In step (3), the specific steps of the rectification process include: feeding the ammonia distillation product into a first rectification tower, heating to 115-120 DEG C for primary rectification, and then feeding the tower bottom product into a second rectification tower, heating to 120-150 DEG C for secondary rectification.

6. The method of claim 1, wherein, In the active component, the mass ratio of the transition metals, the noble metals and the rare earth metals is 10:(1-5):(1-5).

7. The method of claim 1, wherein, The loading amount of the active component is 5-10 wt%.

8. The method of claim 1, wherein, The mass ratio of the carboxymethyl chitosan to the glucosamine hydrochloride is 2:(2-3).

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