An acrylic acid hydrogenation catalyst and a method for preparing the same

Abstract

The application discloses an acrylic acid hydrogenation catalyst and a preparation method thereof. The active component of the acrylic acid hydrogenation catalyst comprises Pd, and the carrier is silica gel or mainly silica gel. The outer surface of the carrier is provided with an organic cage with a regular structure, and the active component is uniformly loaded in the organic cage. The size of the cage cavity of the organic cage is 2.7-3.6 nm. The specific surface area of the acrylic acid hydrogenation catalyst is 50-100 m 2 / g, and the Pd content is 0.2%-0.4% based on 100% of the mass of the acrylic acid hydrogenation catalyst. The acrylic acid hydrogenation catalyst provided by the application can be used in an acrylic acid hydrogenation system by synthesizing an organic cage with a specific size on the outer surface of the carrier to control the size of active particles and by utilizing the anchoring effect of the organic cage to improve the stability of the catalyst.

Description

Technical Field

[0001] This invention relates to the field of propionic acid synthesis technology, and in particular to an acrylic acid hydrogenation catalyst and its preparation method. Background Technology

[0002] Propionic acid is an important fine chemical and basic chemical raw material, widely used in food, feed, rubber, plastics, paints, coatings, fragrances, pharmaceuticals, pesticides, and other fields. It is both an effective preservative and a crucial fine chemical raw material. Propionic acid can be used to prepare other organic chemical raw materials and intermediates, such as propionic anhydride and propionyl chloride.

[0003] The demand for propionic acid has grown rapidly in recent years, and this growth trend is expected to continue for the next few years. In the 1950s, a process for synthesizing acetic acid byproduct propionic acid from the oxidation of light hydrocarbons was developed abroad. In the 1960s, the ethylene carbonylation method was developed, followed by the development of various other technologies such as propionaldehyde oxidation, ethanol carbonylation, acrylonitrile oxidation, and n-propanol oxidation. Currently, domestic propionic acid production technology still uses the traditional light hydrocarbon oxidation method. However, this method involves a complex reaction solution composition, requires special separation and purification measures, and involves significant investment. Therefore, it is essential to develop new and advanced propionic acid production methods.

[0004] Acrylic acid, as an important raw material for organic synthesis and a monomer for synthetic resins, has an increasingly wide range of applications. More than 85% of acrylic acid is produced using the relatively economical propylene oxidation method, which is also the preferred method for large-scale production. Currently, the world has the capacity to produce inexpensive acrylic acid. Therefore, the technology for producing propionic acid through the hydrogenation of acrylic acid shows promise as a cost-effective technology for propionic acid production.

[0005] Currently, there are few reports on the hydrogenation of acrylic acid to propionic acid. Although some progress has been made in Pd-based catalysts, these catalysts all suffer from insufficient stability. For example, Chinese patent document CN114230453A reports a one-step hydrogenation method for propionic acid production, using a Pd-Pt catalyst at a reaction temperature of 60-200℃, achieving an acrylic acid conversion rate of up to 99%. However, the Pd-based catalyst in this technology still suffers from poor catalytic stability and the tendency of acrylic acid to polymerize under certain reaction conditions. Chinese patent document CN114644552A reports a nano-supported ruthenium-carbon catalyst for the hydrogenation of acrylic acid to propionic acid, achieving both acrylic acid conversion and propionic acid yield exceeding 99%. However, this technology only uses activated carbon supported with active rhenium metal for catalytic hydrogenation, resulting in insufficient catalyst stability and limited industrial application value.

[0006] To address the issue of insufficient stability in Pd-based catalysts for the hydrogenation of acrylic acid to propionic acid, Chinese patent document CN114160196A reports a method for preparing a Pd cluster catalyst. This method involves synthesizing organic cages to confine the aggregation of Pd clusters, achieving good hydrogenation activity, selectivity, and stability in the hydrogenation reaction of alkynols. Although the catalyst stability is improved, this catalyst is applied to the hydrogenation of alkynols, a reaction system with low acidity and less stringent stability requirements. Furthermore, the organic cages prepared by this method are relatively small in size, and the catalyst particle size is also small, making catalyst separation somewhat difficult, which is not conducive to large-scale industrial applications.

[0007] Chinese patent document CN111203217A reports a hydrogenation catalyst, which is a three-dimensional organic spherical cage support with a tetraaldehyde-based tetraphenylethylene framework, and is combined with Pd 2+ Re 2+ By achieving coordination, this organic spherical cage / nanoparticle composite can play a synergistic or tandem catalytic role in the hydrogenation of p-tert-butylphenol to prepare cis-p-tert-butylcyclohexanol, exhibiting not only good catalytic activity but also high selectivity for the target product. However, the organic cage in this scheme is mainly used to disperse the particle size of the active center, thereby improving catalytic activity, but whether it improves stability remains to be verified. Summary of the Invention

[0008] To address the problems and areas for improvement in existing technologies, this invention provides an acrylic acid hydrogenation catalyst to solve the problem of insufficient stability of hydrogenation catalysts in acidic systems. The acrylic acid hydrogenation catalyst provided by this invention controls the size of active particles by synthesizing "organic cages" of a specific size on the outer surface of a support, and simultaneously utilizes the anchoring effect of the organic cages to improve the catalyst's stability, thereby enabling the catalyst to be used in acrylic acid hydrogenation systems.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] An acrylic acid hydrogenation catalyst, wherein the active component includes Pd, and the support is silica gel or mainly silica gel; the outer surface of the support has an organic cage with a regular structure, the active component is uniformly loaded in the organic cage, and the cage cavity size of the organic cage is 2.7-3.6 nm;

[0011] The specific surface area of ​​the acrylic acid hydrogenation catalyst is 50-100 m². 2 / g, based on the mass of the acrylic acid hydrogenation catalyst as 100%, the Pd content is 0.2% to 0.4%.

[0012] The propylene hydrogenation catalyst provided by this invention has active components loaded in an organic cage on the outer surface of a support. Due to the physical size limitation of the organic cage, the maximum size of the active center is the size of the cage. Therefore, the size of the active center is also uniform. Under this specific size, the activity requirements of acrylic acid hydrogenation can be met, and the organic cage can also effectively block and fix the active center, effectively reducing the aggregation of the active center. Therefore, the stability of the catalyst is greatly improved and the life of the catalyst is extended. The life of this catalyst is twice that of traditional catalysts. At the same time, since the organic cage is located on the outer surface of the catalyst, the influence of internal diffusion on the catalytic reaction is avoided, resulting in excellent selectivity of the catalyst.

[0013] Optionally, in the acrylic acid hydrogenation catalyst, the silica gel content in the support is greater than 80%, and the support may also contain metal oxides, such as magnesium oxide, titanium oxide, etc. The support can be spherical, cylindrical, clover-shaped, four-leaf clover-shaped, etc.

[0014] Optionally, in the acrylic acid hydrogenation catalyst, the organic cage is located within 0.08 mm of the outer surface of the support extending towards the center.

[0015] Optionally, in the acrylic acid hydrogenation catalyst, the organic cage is prepared by an aldehyde-amine condensation reaction of an aromatic diamine compound and tris(4-formylphenyl)amine; preferably, the aromatic diamine compound is selected from 4,4''-diaminotetraphenyl or Rm-substituted 4,4''-diaminotetraphenyl, wherein Rm is selected from at least one of halogens (F, Cl, Br, I) and C1-C5 straight-chain or branched alkyl groups (methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, etc.).

[0016] The present invention also provides a method for preparing the above-mentioned acrylic acid hydrogenation catalyst, comprising the following steps:

[0017] 1) Completely polymerize the hydrophilic polymerizable monomer in the pores of the carrier, and the resulting polymer does not decompose. Control the polymer to occupy more than 80% of the pore volume of the carrier (during the experiment, the required mass or volume of the polymerizable monomer can be calculated based on the mass of the carrier and relevant parameters such as the water absorption rate and pore volume of the carrier, so as to control the polymer to occupy more than 80% of the pore volume of the carrier), and obtain the semi-finished catalyst A.

[0018] 2) Dissolve tris(4-formylphenyl)amine and the catalyst in a solvent and mix with the semi-finished catalyst A to obtain a mixture; add a solution of aromatic diamine compound dropwise to the mixture to carry out an aldehyde-amine condensation reaction to form an organic cage-like substance; after the reaction is completed, pour off the residual liquid, wash with alcohol and deionized water respectively, and dry to obtain semi-finished catalyst B.

[0019] 3) Under stirring, a solution of the organopalladium compound (the organopalladium compound is completely dissolved in a good solvent, which is a solvent that can dissolve the organopalladium compound) is added dropwise to the mixture of the semi-finished catalyst B and the alcohol. After the organopalladium compound is fully loaded (i.e., the organopalladium compound is fully loaded in the organic cage-like structure of the semi-finished catalyst B, and the surface of the semi-finished catalyst B no longer changes color, it is considered fully loaded), the mixture is washed with deionized water, dried, and calcined at ≤400℃ to completely decompose the polymer, yielding the semi-finished catalyst C.

[0020] 4) The semi-finished catalyst C is mixed with a reducing agent to reduce palladium. After the palladium is completely reduced, the solution is poured off, washed with deionized water, and dried to obtain the acrylic acid hydrogenation catalyst.

[0021] The molar ratio of the tris(4-formylphenyl)amine to the aromatic diamine compound is 1:1.1 to 2.2.

[0022] In step 3) above, the purpose of forming a mixture of the semi-finished catalyst B and the alcohol is to disperse the semi-finished catalyst B and improve the uniformity of the organic palladium compound loading.

[0023] In traditional hydrogenation catalysts, the hydrogenation of olefins occurs at the main active site, Pd. During catalyst preparation, activation is a high-temperature calcination process, during which metal salts typically decompose into metal oxides, which then form clusters. However, the aggregation of active components during calcination is a random process, resulting in the formation of mostly normally distributed active sites with a size of 1-5 nm. These active sites are prone to aggregation, which reduces the catalyst's activity and stability.

[0024] The present invention addresses the aforementioned catalyst clustering problem as follows: To ensure the active centers are located on the outer surface of the catalyst, an organic cage needs to be synthesized on the outer surface. Specifically, before the organic cage synthesis, an easily decomposable organic polymer is formed in situ inside the support, occupying the internal pores of the support, allowing the organic cage to be synthesized within the pores near the outer surface (ensuring the organic cage is located on the outer surface of the support). After the synthesis of organic cages with uniform size, the active component, an organopalladium compound (an organic precursor salt of Pd), is loaded within the organic cage. The anchoring effect of the organic cage prevents the aggregation of the active component and its diffusion into the support. Then, at a temperature lower than the decomposition temperature of the organic cage, the organic polymer in the pores of the support decomposes, ultimately yielding a catalyst with high stability and high activity. Simultaneously, the catalyst's resistance to water and acid is improved, which is of great significance for further extending the catalyst's operating time.

[0025] Optionally, in step 4) of the preparation method of the acrylic acid hydrogenation catalyst provided by the present invention, the semi-finished catalyst C can be mixed with a solvent, and then mixed with the reducing agent. After the palladium is completely reduced, the solution is decanted, washed with deionized water, and dried to obtain the acrylic acid hydrogenation catalyst. Preferably, the reducing agent is selected from methanol, formaldehyde, formic acid, ethanol, acetaldehyde, or hydrazine hydrate, and the solvent is selected from ethanol or deionized water. The reducing agent can be added directly or dropwise to the mixture of the semi-finished catalyst C and the solvent.

[0026] Specifically, as in step 4), the semi-finished catalyst C can be thoroughly mixed with the reducing agent. After the palladium is completely reduced, the solution is poured off, washed with deionized water, and dried to obtain the acrylic acid hydrogenation catalyst; or

[0027] After thoroughly mixing the semi-finished catalyst C with a solvent (deionized water or ethanol), a reducing agent is added and stirred for reduction. After the palladium is completely reduced, the solution is poured off, washed with deionized water, and dried to obtain the acrylic acid hydrogenation catalyst.

[0028] Optionally, in the preparation method of the acrylic acid hydrogenation catalyst provided by the present invention, the mass ratio of palladium in the organopalladium compound to tris(4-formylphenyl)amine is 2 to 14:1.

[0029] By limiting the molar ratio of tris(4-formylphenyl)amine to the aromatic diamine compound, and combining this with the mass ratio of palladium in the organopalladium compound to tris(4-formylphenyl)amine, the mass ratio of the organic cage to palladium in the organopalladium compound is indirectly limited, thereby further improving the uniformity of palladium distribution in the organic cage.

[0030] Optionally, in the preparation method of the acrylic acid hydrogenation catalyst provided by the present invention, in step 1), the volume of the hydrophilic polymerizable monomer is 80%-100% of the pore volume of the support, preferably 80%-95%.

[0031] Optionally, in the preparation method of the acrylic acid hydrogenation catalyst provided by the present invention, in step 1), the hydrophilic polymerizable monomer is selected from organic compounds containing carbonyl, carboxyl or carbon-carbon double bonds, and is capable of polymerization or condensation. The specific polymerization or condensation temperature and conditions can be adjusted according to the polymerizable monomer used. Preferably, the hydrophilic polymerizable monomer is selected from acrylic acid, acrylate or lactic acid, etc., and conventional polymerization conditions in the industry can be used.

[0032] Optionally, in the preparation method of the acrylic acid hydrogenation catalyst provided by the present invention, in step 2), the catalyst is a haloacetic acid, preferably fluoroacetic acid or chloroacetic acid, more preferably trifluoroacetic acid or dichloroacetic acid;

[0033] The mass ratio of the tris(4-formylphenyl)amine to the catalyst is 2000 to 6000:1.

[0034] Optionally, in the preparation method of the acrylic acid hydrogenation catalyst provided by the present invention, in step 3), the organopalladium compound is selected from palladium acetate or palladium acetylacetonate.

[0035] Optionally, in the preparation method of the acrylic acid hydrogenation catalyst provided by the present invention, in step 4), the reducing agent is selected from methanol, formaldehyde, formic acid, ethanol, acetaldehyde, or hydrazine hydrate, etc.

[0036] In the preparation method of the acrylic acid hydrogenation catalyst provided by this invention, the solvents involved and the solvents used in the solutions are not specifically limited, as long as they can dissolve the corresponding substances, such as tris(4-formylphenyl)amine and the catalyst dissolved in a solvent, a solution of an aromatic diamine compound, or a solution of an organopalladium compound. The specific solvent used in these three solutions only needs to be able to dissolve the corresponding solutes. The solvent recommended by this invention is a haloalkanes, preferably fluoroalkanes, chloroalkanes, or bromoalkanes, and more preferably dichloroethane or trichloromethane. The specific solvent can be adjusted according to the properties of the actual compound. For example, when the organopalladium compound is palladium chloride or palladium acetate, hydrochloric acid or glacial acetic acid can be used for dissolution.

[0037] In the preparation method of the acrylic acid hydrogenation catalyst provided by this invention, the polymerization temperature and time parameters in step 1) can be adjusted according to the properties and amounts of the polymerizable monomers used, as long as the polymerizable monomers can be completely polymerized and do not decompose during the polymerization process. In step 2), the conditions for the aldehyde-amine condensation reaction between tris(4-formylphenyl)amine and aromatic diamine compounds can be adjusted according to the actual material ratio and the catalyst used, as long as the aldehyde-amine condensation reaction can be carried out to form an organic cage structure on the outer surface of the support. In step 3), the parameters for loading the organopalladium compound can be adjusted according to the concentration of the actual organopalladium compound solution, etc., to achieve effective loading of the organopalladium compound; the calcination temperature should be such that the pore structure of the support is not destroyed (i.e., less than 400℃) to achieve complete decomposition of the polymer. In step 4), the parameters for reducing palladium can use industry-standard methods, which can be adjusted according to actual conditions. The drying parameters in each step can also use industry-standard methods.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] Beneficial Effect 1: The acrylic acid hydrogenation catalyst provided by this invention uses silica gel or mainly silica gel as a support, places an organic cage on the outer surface of the support, defines the cage cavity size of the organic cage, and loads the active components, including palladium, into the organic cage. By utilizing the anchoring effect of the organic cage itself, the aggregation and migration of the active components are effectively prevented, which greatly improves the stability of the catalyst in the acidic system. The evaluation results after 1000 hours show that the hydrogenation activity and selectivity are basically not reduced.

[0040] Beneficial Effect 2: The preparation method of the acrylic acid hydrogenation catalyst provided by this invention first occupies most of the pores inside the support with a decomposable polymer, ensuring that the organic cage grows on the outer surface of the support in the later stage. After loading the active component Pd and other components into the organic cage, the polymer is heated and decomposed to release the pores inside the support (the pores occupied by the polymer) without destroying the pore structure of the catalyst. Combined with controlling the proportion of in-situ synthesized decomposable polymer monomers, the cage cavity size of the organic cage is matched with the optimal active center packing size required for acrylic acid hydrogenation (i.e., the size of the active center is controlled by the cage cavity size of the organic cage). This effectively uses the decomposable polymer to prevent Pd particles from migrating into the support, and uses the organic cage on the outer surface of the support to control the lateral agglomeration of Pd crystals, so that the active component is uniformly distributed in the organic cage. The catalyst has extremely high activity and selectivity. The evaluation results show that the conversion rate of acrylic acid hydrogenation reaches more than 95% and the selectivity is 100%. Attached Figure Description

[0041] Figure 1 This is a simulation diagram of the organic cage in the acrylic acid hydrogenation catalyst prepared in Example 6. Detailed Implementation

[0042] The following provides a detailed description of the embodiments of the present invention: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and processes. However, the scope of protection of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0043] Source of raw materials or equipment:

[0044] The BET measuring instrument, manufactured by Mack Corporation in the United States, is used to measure specific surface area and the size of organic cages.

[0045] Digital microscope, Shanghai No. 5 Optical Factory, 19JC digital universal tool microscope.

[0046] The A240FS atomic absorption spectrometer and the Agilent 7890A gas chromatograph were used to determine the Pd content in the catalyst; and to measure the hydrogen, acrylic acid, and propionic acid content at the reactor outlet and inlet when evaluating the performance of the catalyst in the hydrogenation reaction of acrylic acid.

[0047] The technical solution of the present invention is further illustrated below through specific embodiments, but these should not be construed as limiting the present invention.

[0048] Example 1

[0049] Carrier: Commercially available spherical silica carrier with a diameter of 2 mm was used. After calcination at 1050℃ for 4 hours, the water absorption rate and pore volume were 0.65 m³ / s. 3 / g, specific surface area 50m² 2 / g. Weigh 100g of the carrier.

[0050] Catalyst preparation:

[0051] (1) Weigh 73.5g of lactic acid and mix it with 100g of calcined support. Keep the temperature at 160℃ for 10 hours to obtain semi-finished catalyst A.

[0052] (2) Mix 0.2g of tris(4-formylphenyl)amine with 0.1mg of dichloroacetic acid, dissolve in 60ml of dichloroethane, then mix with semi-finished catalyst A, stir and add dropwise a mixed solution of 0.234g of 4,4''-diaminotetraphenyl and 10ml of trichloroethane, let the mixture stand at room temperature for 200 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry at 120℃ to obtain semi-finished catalyst B;

[0053] (3) Dissolve 1.145 g of palladium acetylacetonate in 50 mL of chloroform. After the palladium acetylacetonate is completely dissolved, immerse the semi-finished catalyst B in 50 mL of ethanol. Add the prepared palladium acetylacetonate chloroform solution dropwise to the mixture of semi-finished catalyst B and ethanol. Stir for 30 hours, let stand for 5 hours, pour off the solution, wash with deionized water, dry at 120 °C, and calcine at 360 °C for 8 hours to obtain semi-finished catalyst C.

[0054] (4) Immerse the semi-finished catalyst C in an ethanol solution, stir at 75°C for 1 hour, decompose the solution, wash with deionized water, and dry at 120°C to obtain the acrylic acid hydrogenation catalyst.

[0055] Comparative Example 1

[0056] Carrier: The same carrier as in Example 1 was used;

[0057] The catalyst preparation process is similar to that in Example 1, except that lactic acid was not added in step (1).

[0058] Catalyst preparation:

[0059] (1) Weigh 100g of the calcined carrier and call it A1;

[0060] (2) Take 0.2g of tris(4-formylphenyl)amine and 0.1mg of dichloroacetic acid, dissolve them in 60ml of dichloroethane, then mix them with A1, stir and add dropwise a mixed solution of 0.234g of 4,4''-diaminotetraphenyl and 10ml of trichloroethane, let the mixture stand at room temperature for 200 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry at 120℃ to obtain semi-finished catalyst B1;

[0061] (3) Dissolve 1.145 g of palladium acetylacetonate in 50 mL of chloroform. After the palladium acetylacetonate is completely dissolved, immerse the semi-finished catalyst B1 in 50 mL of ethanol. Add the prepared palladium acetylacetonate chloroform solution dropwise to the mixture of semi-finished catalyst B1 and ethanol. Stir for 30 hours, let stand for 5 hours, pour off the solution, wash with deionized water, dry at 120 °C, and calcine at 360 °C for 8 hours to obtain semi-finished catalyst C1.

[0062] (4) Immerse the semi-finished catalyst C in an ethanol solution, stir at 75°C for 1 hour, decompose the solution, wash with deionized water, and dry at 120°C to obtain the acrylic acid hydrogenation catalyst.

[0063] Example 2

[0064] Catalyst support: Commercially available spherical silica gel support with a diameter of 2 mm was used. After calcination at 850℃ for 4 hours, the water absorption rate and pore volume were measured to be 0.5 ml / g, and the specific surface area was 100.5 m². 2 / g. Weigh 100g of the carrier.

[0065] Catalyst preparation:

[0066] (1) Weigh 40.6g of an aqueous solution with 30% acrylic acid content, 0.02g of potassium hypophosphite monohydrate, 0.045g of copper acetate monohydrate, and 0.3ml of 35% hydrogen peroxide as an initiator. After mixing evenly, add 100g of calcined carrier. After the solution is completely absorbed, transfer it to a reflux flask and heat it to 80℃ with stirring. Keep the temperature constant for 1 hour to obtain the semi-finished catalyst D.

[0067] (2) Take 0.0143 g of tris(4-formylphenyl)amine and 0.0023 mg of dichloroacetic acid, dissolve them in 50 ml of dichloroethane, and then mix them with the semi-finished catalyst D. Stir and add dropwise a mixed solution of 0.0316 g of 4,4''-diaminotetraphenyl and 10 ml of dichloroethane. After the addition is complete, let it stand at room temperature for 200 hours, pour off the residual liquid, wash it with ethanol and deionized water respectively, and dry it at 60 °C to obtain the semi-finished catalyst E.

[0068] (3) Dissolve 0.422 g of palladium acetate in 50 mL of glacial acetic acid. After the palladium acetate is completely dissolved, an acetic acid solution of palladium acetate is obtained. Immerse the semi-finished catalyst E in 50 mL of ethanol. Then add the prepared palladium acetate solution dropwise to the mixture of semi-finished catalyst E and ethanol. Stir for 30 hours, pour off the solution, wash with deionized water, dry at 120 °C to remove the solvent, and calcine at 400 °C for 8 hours to obtain semi-finished catalyst F.

[0069] (4) Immerse the semi-finished catalyst F in deionized water, then add 5 ml of 5% hydrazine hydrate solution, stir for 1 hour at room temperature, pour off the solution, wash with deionized water, and dry at 100°C to obtain the acrylic acid hydrogenation catalyst.

[0070] Comparative Example 2

[0071] Catalyst support: Same as in Example 2.

[0072] The catalyst preparation process is similar to that in Example 2, except that the amount of 4,4''-diaminotetraphenyl is different.

[0073] Catalyst preparation:

[0074] (1) Weigh 40.6g of an aqueous solution with 30% acrylic acid content, 0.02g of potassium hypophosphite monohydrate, 0.045g of copper acetate monohydrate, and 0.3ml of 35% hydrogen peroxide as an initiator. After mixing evenly, add 100g of calcined carrier. After the solution is completely absorbed, transfer it to a reflux flask and heat it to 80℃ with stirring. Keep the temperature constant for 1 hour to obtain the semi-finished catalyst D1.

[0075] (2) Take 0.0143 g of tris(4-formylphenyl)amine and 0.0023 mg of dichloroacetic acid, dissolve them in 50 ml of dichloroethane, and then mix them with the semi-finished catalyst D1. Stir and add dropwise a mixed solution of 0.0129 g of 4,4''-diaminotetraphenyl and 10 ml of dichloroethane. After the addition is complete, let it stand at room temperature for 200 hours, pour off the residual liquid, wash it with ethanol and deionized water respectively, and dry it at 60 °C to obtain the semi-finished catalyst E1.

[0076] (3) Dissolve 0.422 g of palladium acetate in 50 mL of glacial acetic acid. After the palladium acetate is completely dissolved, an acetic acid solution of palladium acetate is obtained. Immerse the semi-finished catalyst E1 in 50 mL of ethanol. Then add the prepared palladium acetate solution dropwise to the mixture of semi-finished catalyst E and ethanol. Stir for 30 hours, pour off the solution, wash with deionized water, dry at 120 °C to remove the solvent, and calcine at 400 °C for 8 hours to obtain semi-finished catalyst F1.

[0077] (4) Immerse the semi-finished catalyst F1 in deionized water, then add 5 ml of 5% hydrazine hydrate solution, stir for 1 hour at room temperature, pour off the solution, wash with deionized water, and dry at 100°C to obtain the acrylic acid hydrogenation catalyst.

[0078] Example 3

[0079] Catalyst support: Commercially available spherical silica gel support with a diameter of 2.5 mm was used. After calcination at 980℃ for 4 hours, the water absorption rate and pore volume were measured to be 0.58 ml / g, and the specific surface area was 71.2 m². 2 / g. Weigh 100g of the carrier.

[0080] Catalyst preparation:

[0081] (1) Weigh 62.11g of lactic acid and mix it with 100g of calcined support. Keep the temperature at 160℃ for 10 hours to obtain semi-finished catalyst G;

[0082] (2) Weigh 0.0375 g of tris(4-formylphenyl)amine and mix it with 0.0125 mg of dichloroacetic acid. Dissolve the mixture in 50 ml of dichloroethane. Then mix it with the semi-finished catalyst G, stir and add dropwise a mixed solution of 0.0542 g of 4,4''-diaminotetraphenyl and 10 ml of dichloroethane. After the addition is complete, let it stand at room temperature for 200 hours, pour off the residual liquid, wash it with ethanol and deionized water respectively, and dry it at 80 °C to obtain the semi-finished catalyst H.

[0083] (3) Dissolve 0.63 g of palladium acetate in 50 ml of glacial acetic acid. After the palladium acetate is completely dissolved, a palladium acetate solution is obtained. Immerse the semi-finished catalyst H in 50 ml of ethanol. Add the prepared palladium acetate solution dropwise to the mixture of semi-finished catalyst H and ethanol. Stir for 10 hours, let stand for 3 hours, pour off the solution, wash with deionized water, dry at 120 °C, and calcine at 350 °C for 8 hours to obtain the semi-finished catalyst J.

[0084] (4) Add 50 ml of deionized water to the semi-finished catalyst J, then add 20 ml of formaldehyde solution, heat to boiling and stir for 10 minutes, pour off the solution, wash with deionized water, and dry at 120°C to obtain the desired catalyst.

[0085] Comparative Example 3

[0086] Catalyst support: Same as in Example 3.

[0087] The catalyst preparation process is similar to that in Example 3, except that the aromatic diamine compound used in the comparative example is benzidine.

[0088] Catalyst preparation:

[0089] (1) Weigh 62.11g of lactic acid and mix it with 100g of calcined support. Keep the temperature at 160℃ for 10 hours to obtain semi-finished catalyst G1.

[0090] (2) Weigh 0.0375 g of tris(4-formylphenyl)amine and mix it with 0.0125 mg of dichloroacetic acid. Dissolve the mixture in 50 ml of dichloroethane. Then mix it with the semi-finished catalyst G1, stir and add a mixed solution of 0.0296 g of benzidine and 10 ml of dichloroethane dropwise. After the addition is complete, let it stand at room temperature for 200 hours, pour off the residual liquid, wash it with ethanol and deionized water respectively, and dry it at 80 °C to obtain the semi-finished catalyst H1.

[0091] (3) Dissolve 0.63g of palladium acetate in 50ml of glacial acetic acid. After the palladium acetate is completely dissolved, a palladium acetate solution is obtained. Immerse the semi-finished catalyst H1 in 50ml of ethanol. Add the prepared palladium acetate solution dropwise to the mixture of semi-finished catalyst H1 and ethanol. Stir for 10 hours, let stand for 3 hours, pour off the solution, wash with deionized water, dry at 120℃, and calcine at 350℃ for 8 hours to obtain the semi-finished catalyst J1.

[0092] (4) Add 50 ml of deionized water to the semi-finished catalyst J1, then add 20 ml of formaldehyde solution, heat to boiling and stir for 10 minutes, pour off the solution, wash with deionized water, and dry at 120℃ to obtain the desired catalyst.

[0093] Example 4

[0094] Carrier: Commercially available spherical silica gel carrier with a diameter of 3 mm was used. After calcination at 950℃ for 4 hours, the water absorption rate and pore volume were 0.60 ml / g, and the specific surface area was 80.8 m². 2 / g. Weigh 100g of the carrier.

[0095] Catalyst preparation:

[0096] (1) Weigh 65.69g of lactic acid and mix it with 100g of the calcined support. Keep the temperature at 160℃ for 2 hours to obtain the semi-finished catalyst K.

[0097] (2) Take 0.058 g of tris(4-formylphenyl)amine and 0.0116 mg of trifluoroacetic acid, dissolve them in 50 ml of dichloroethane, and then mix them with the semi-finished catalyst K. Stir and add dropwise a mixed solution of 0.1 g of 2-methyl-4,4''-diaminotetraphenyl and 10 ml of dichloroethane. After the addition is complete, let it stand at room temperature for 80 hours, pour off the residual liquid, wash it with ethanol and deionized water respectively, and dry it at 100 °C to obtain the semi-finished catalyst M.

[0098] (3) Dissolve 1.0 g of palladium acetylacetonate in 50 ml of chloroform. After the palladium acetylacetonate is completely dissolved, a palladium acetylacetonate solution is obtained. Immerse the semi-finished catalyst M in 50 ml of ethanol. Add the prepared palladium acetylacetonate solution dropwise to the mixture of semi-finished catalyst M and ethanol. Stir for 12 hours, let stand for 6 hours, pour off the solution, wash with deionized water, dry at 90°C, and calcine at 380°C for 4 hours to obtain semi-finished catalyst N.

[0099] (4) Add 50 ml of ethanol solution to the semi-finished catalyst N, then add 20 ml of formic acid solution dropwise, stir at 25°C for 20 minutes, pour off the solution, wash with ethanol, and dry at 100°C to obtain the acrylic acid hydrogenation catalyst.

[0100] Comparative Example 4

[0101] Carrier: Same as in Example 4.

[0102] The catalyst preparation process is similar to that in Example 4, except that the lactic acid polymerization temperature in Comparative Example 4 is 280°C.

[0103] Catalyst preparation:

[0104] (1) Weigh 65.69g of lactic acid and mix it with 100g of the calcined support. Keep the temperature at 280℃ for 2 hours to obtain the semi-finished catalyst K1.

[0105] (2) Take 0.058 g of tris(4-formylphenyl)amine and 0.0116 mg of trifluoroacetic acid, dissolve them in 50 ml of dichloroethane, and then mix them with the semi-finished catalyst K1. Stir and add dropwise a mixed solution of 0.1 g of 2-methyl-4,4''-diaminotetraphenyl and 10 ml of dichloroethane. After the addition is complete, let it stand at room temperature for 80 hours, pour off the residual liquid, wash it with ethanol and deionized water respectively, and dry it at 100 °C to obtain the semi-finished catalyst M1.

[0106] (3) Dissolve 1.0 g of palladium acetylacetonate in 50 ml of chloroform. After the palladium acetylacetonate is completely dissolved, a palladium acetylacetonate solution is obtained. Immerse the semi-finished catalyst M1 in 50 ml of ethanol. Add the prepared palladium acetylacetonate solution dropwise to the mixture of semi-finished catalyst M1 and ethanol. Stir for 12 hours, let stand for 6 hours, pour off the solution, wash with deionized water, dry at 90°C, and calcine at 380°C for 4 hours to obtain semi-finished catalyst N1.

[0107] (4) Add 50 ml of ethanol solution to the semi-finished catalyst N1, then add 20 ml of formic acid solution dropwise, stir at 25°C for 20 minutes, pour off the solution, wash with ethanol, and dry at 100°C to obtain the acrylic acid hydrogenation catalyst.

[0108] Example 5

[0109] Carrier: Commercially available spherical silica gel-titanium oxide carriers were used, with a titanium oxide content of 20% and a diameter of 4 mm. After calcination at 900℃ for 4 hours, the water absorption rate and pore volume were 0.62 ml / g, and the specific surface area was 89.2 m². 2 / g. Weigh 100g of the carrier.

[0110] Catalyst preparation:

[0111] (1) Weigh 55.37g of 25% acrylic acid solution, 0.015g of potassium hypophosphite monohydrate, 0.028g of copper acetate monohydrate, and 0.2ml of 30% hydrogen peroxide as initiator. After mixing evenly, add 100g of the above-mentioned calcined carrier. After the solution is completely absorbed, transfer it to a reflux flask and heat it to 85℃ with stirring. Keep the temperature constant for 1 hour to obtain the semi-finished catalyst O.

[0112] (2) Take 0.0625 g of tris(4-formylphenyl)amine and 0.0125 mg of trichloroacetic acid, dissolve them in 50 ml of dichloroethane, and then mix them with the semi-finished catalyst O. Stir and add dropwise a mixed solution of 0.115 g of 4,4''-diaminotetraphenyl and 10 ml of trichloroethane. After the addition is complete, let it stand at room temperature for 150 hours, pour off the residual liquid, wash it with ethanol and deionized water respectively, and dry it at 90 °C to obtain the semi-finished catalyst P.

[0113] (3) Dissolve 0.716 g of palladium acetylacetonate in 50 ml of chloroform until the palladium acetylacetonate is completely dissolved to obtain a palladium acetylacetonate solution. Immerse the semi-finished catalyst P in 50 ml of ethanol, add the prepared palladium acetylacetonate solution dropwise to the mixture of semi-finished catalyst P and ethanol, stir for 20 hours, let stand for 4 hours, decant the solution, wash with deionized water, dry at 110 °C, and calcine at 400 °C for 2 hours to obtain the semi-finished catalyst Q;

[0114] (4) Immerse the semi-finished catalyst Q in 50 ml of ethanol, then add 25 ml of acetaldehyde, stir at 70 °C for 2 hours, pour off the solution, wash with deionized water, and dry at 120 °C to obtain the acrylic acid hydrogenation catalyst.

[0115] Comparative Example 5

[0116] Carrier: Same as in Example 5

[0117] Catalyst preparation: The catalyst prepared in this comparative example has the same active component content as the catalyst prepared in Example 5. The specific steps are as follows:

[0118] (1) Weigh 0.42 palladium chloride and dissolve it in hydrochloric acid. Dilute the solution with deionized water to 62 ml, adjust the pH to 2.5, mix it with 100 g of the above-mentioned calcined support, stir until the solution is completely absorbed, dry at 90 °C, and calcine at 500 °C for 4 h to obtain the semi-finished catalyst O1.

[0119] (2) Immerse the semi-finished catalyst O1 in 50ml of ethanol, then add 25ml of acetaldehyde, stir at 70℃ for 2 hours, pour off the solution, wash with deionized water, and dry at 120℃ to obtain the acrylic acid hydrogenation catalyst.

[0120] Example 6

[0121] Carrier: A commercially available toothed spherical silica-magnesium oxide carrier with a magnesium oxide content of 5% and a diameter of 3 mm was used. After calcination at 1030℃ for 4 hours, the water absorption rate and pore volume were 0.54 ml / g, and the specific surface area was 60.1 m². 2 / g. Weigh 100g of the carrier.

[0122] Catalyst preparation:

[0123] (1) Weigh 54.6g of lactic acid and mix it with 100g of the calcined support. Keep the temperature at 170℃ for 2 hours to obtain the semi-finished catalyst R.

[0124] (2) Take 0.11 g of tris(4-formylphenyl)amine and 0.044 mg of trifluoroacetic acid, dissolve them in 50 ml of dichloroethane, and then mix them with the semi-finished catalyst R. Stir and add dropwise a mixed solution of 0.25 g of 3-chloro-4,4''-diaminotetraphenyl and 10 ml of dichloroethane. Let it stand at room temperature for 180 hours, pour off the residue, wash it with ethanol and deionized water respectively, and dry it at 60 °C to obtain the semi-finished catalyst S.

[0125] (3) Dissolve 0.696 g of palladium acetate in 50 ml of chloroform until the palladium acetate is completely dissolved to obtain a palladium acetate solution. Immerse the semi-finished catalyst S in 50 ml of ethanol, and add the prepared palladium acetate solution dropwise to the mixture of semi-finished catalyst S and ethanol. Stir for 15 hours, let stand for 4 hours, decant the solution, wash with deionized water, dry at 120 °C, and calcine at 400 °C for 2 hours to obtain the semi-finished catalyst T.

[0126] (4) Immerse the semi-finished catalyst T in 60 ml of deionized water, then add 5 ml of 5% hydrazine hydrate solution, stir for 1 hour at room temperature, pour off the solution, wash with deionized water, and dry at 120°C to obtain the acrylic acid hydrogenation catalyst.

[0127] Figure 1 This is a simulation diagram of the organic cage in the acrylic acid hydrogenation catalyst prepared in this embodiment. Figure 1It can be seen that the size range of the organic cage is 2.91~3.53 nm, which is consistent with the results measured by the BET measuring instrument.

[0128] Comparative Example 6

[0129] Carrier: Same as in Example 6.

[0130] The catalyst preparation was similar to that in Example 6, except that the calcination temperature in step (3) of this comparative example was 220°C. The catalyst preparation process in this comparative example is as follows:

[0131] Catalyst preparation:

[0132] (1) Weigh 54.6g of lactic acid and mix it with 100g of the calcined support. Keep the temperature at 170℃ for 2 hours to obtain the semi-finished catalyst R1.

[0133] (2) Take 0.11 g of tris(4-formylphenyl)amine and 0.044 mg of trifluoroacetic acid, dissolve them in 50 ml of dichloroethane, and then mix them with the semi-finished catalyst R. Stir and add dropwise a mixed solution of 0.25 g of 3-chloro-4,4''-diaminotetraphenyl and 10 ml of dichloroethane. Let it stand at room temperature for 180 hours, pour off the residue, wash it with ethanol and deionized water respectively, and dry it at 60 °C to obtain the semi-finished catalyst S1.

[0134] (3) Dissolve 0.696 g of palladium acetate in 50 ml of chloroform until the palladium acetate is completely dissolved to obtain a palladium acetate solution. Immerse the semi-finished catalyst S1 in 50 ml of ethanol, and add the prepared palladium acetate solution dropwise to the mixture of semi-finished catalyst S1 and ethanol. Stir for 15 hours, let stand for 4 hours, decant the solution, wash with deionized water, dry at 120 °C, and calcine at 220 °C for 2 hours to obtain the semi-finished catalyst T1.

[0135] (4) Immerse the semi-finished catalyst T1 in 60 ml of deionized water, then add 5 ml of 5% hydrazine hydrate solution, stir for 1 hour at room temperature, pour off the solution, wash with deionized water, and dry at 120°C to obtain the acrylic acid hydrogenation catalyst.

[0136] Example 7

[0137] Carrier: Spherical silica-magnesium oxide carrier with a magnesium oxide content of 10% and a diameter of 2 mm was used. After calcination at 965℃ for 4 hours, the water absorption rate and pore volume were 0.54 ml / g, and the specific surface area was 75 m². 2 / g. Weigh 100g of the carrier.

[0138] Catalyst preparation:

[0139] (1) Weigh 51.4g of lactic acid and mix it with 100g of the calcined support. Keep the temperature at 165℃ for 2 hours to obtain the semi-finished catalyst U.

[0140] (2) Take 0.12g of tris(4-formylphenyl)amine and 0.06mg of trifluoroacetic acid, dissolve them in 50ml of dichloroethane, and then mix them with the semi-finished catalyst U to obtain a mixture. Then, under stirring, add dropwise a mixed solution of 0.185g of 4,4''-diaminotetraphenyl and 10ml of dichloroethane to the mixture. Let it stand at room temperature for 190 hours, pour off the residue, wash it with ethanol and deionized water respectively, and dry it at 100℃ to obtain the semi-finished catalyst V.

[0141] (3) Dissolve 0.859 g of palladium acetylacetonate in 50 ml of benzene. After the palladium acetylacetonate is completely dissolved, a palladium acetylacetonate solution is obtained. Immerse the semi-finished catalyst V in 50 ml of methanol solution, and then add the palladium acetylacetonate solution dropwise to the mixture of semi-finished catalyst V and methanol. Stir for 30 hours, let stand for 4 hours, pour off the solution, wash with deionized water, dry at 120 °C, and calcine at 380 °C for 1 hour to obtain semi-finished catalyst W.

[0142] (4) Immerse the semi-finished catalyst W in 60 ml of deionized water, then add 5 ml of 5% hydrazine hydrate solution dropwise. After the addition is complete, stir at room temperature for 1 hour, pour off the solution, wash with deionized water, and dry at 120°C to obtain the acrylic acid hydrogenation catalyst.

[0143] Comparative Example 7

[0144] The preparation process of the acrylic acid hydrogenation catalyst provided in this comparative example is similar to that in Example 7, except that no support is used in this comparative example, and step (1) is omitted. The specific preparation process of the acrylic acid hydrogenation catalyst in this comparative example is as follows:

[0145] (1) Take 0.12 g of tris(4-formylphenyl)amine and 0.06 mg of trifluoroacetic acid, dissolve them in 50 ml of dichloroethane, stir and add dropwise a mixed solution of 0.185 g of benzidine and 10 ml of dichloroethane, let stand at room temperature for 190 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry at 100 °C to obtain semi-finished catalyst V1;

[0146] (2) Dissolve 0.859 g of palladium acetylacetonate in 50 ml of benzene. After the palladium acetylacetonate is completely dissolved, a palladium acetylacetonate solution is obtained. Immerse the semi-finished catalyst V1 in 50 ml of methanol, and then add the palladium acetylacetonate solution dropwise to the mixture of semi-finished catalyst V1 and methanol. Stir for 30 hours, let stand for 4 hours, pour off the solution, wash with deionized water, dry at 120°C, and calcine at 380°C for 1 hour to obtain semi-finished catalyst W1.

[0147] (3) Immerse the semi-finished catalyst W1 in 60g of deionized water, then add 5ml of 5% hydrazine hydrate solution dropwise. After the addition is complete, stir at room temperature for 1 hour, pour off the solution, wash with deionized water, and dry at 120℃ to obtain the acrylic acid hydrogenation catalyst.

[0148] The performance of the acrylic acid hydrogenation catalysts prepared in each embodiment and comparative example was measured by atomic absorption spectrometry (based on the mass of the acrylic acid hydrogenation catalyst being 100%), by BET analyzer (to measure the specific surface area and the cage cavity size of the organic cage), and by microscope (to measure the distribution thickness of palladium (i.e., the depth of the organic cage extending from the outer surface of the support towards the center). The specific test results are shown in the table below.

[0149] Table 1

[0150]

[0151] Note: The palladium content in Comparative Example 7 is based on the total mass of the synthesized organic cage and palladium as 100%.

[0152] Performance of catalysts in the hydrogenation reaction of acrylic acid

[0153] Evaluation method: The catalyst loading in the fixed-bed single-stage reactor was 100 mL (weight recorded), the packing material was 50 mL, and the liquid hourly space velocity of the reactants was 2.0 h⁻¹. -1 The operating pressure is 2.5 MPa, the hydrogen-to-oil ratio is 20, and the reactor inlet temperature is 40 ℃.

[0154] The acrylic acid hydrogenation catalysts prepared in each embodiment and comparative example were evaluated according to the evaluation method described above, and the specific evaluation results are shown in the table below.

[0155] Table 2 Catalyst Evaluation Results

[0156]

[0157] As can be seen from the data in Tables 1 and 2 above, compared with Example 1, in Comparative Example 1, since no polymer was formed in the inner pores of the carrier to occupy the internal channels beforehand, the active components were distributed in all the spaces of the carrier channels. Due to the diffusion limitation of the reaction, its acrylic acid conversion rate was less than 80%.

[0158] Compared with Example 2, in Comparative Example 2, because the molar number of 4,4''-diaminotetraphenyl in step (2) is 0.9 times the molar number of tris(4-formylphenyl)amine, that is, the number of molecules of the second monomer is insufficient, the synthesis of the organic cage cannot be completed. The synthesized organic cage is too small and has a wide size distribution, that is, the size of the final part of the active center is not within the optimal range and has no activity. Therefore, the overall activity of the catalyst is low. Some monomers that have not been hydrogenated stay on the catalyst for too long and undergo polymerization reaction. After 1000 hours, the selectivity of the catalyst is significantly reduced.

[0159] Compared with Example 3, Comparative Example 3 used benzidine as the second monomer, which has a molecular size that is significantly smaller than 4,4''-diaminotetraphenyl. The synthesized organic cage is only about 2 nm, which is significantly smaller than the optimal active center size for the hydrogenation of acrylic acid. The catalyst activity is low, and some monomers that have not been hydrogenated have a longer residence time on the catalyst and undergo polymerization. After 1000 hours, the catalyst selectivity decreases more than that in Comparative Example 2.

[0160] In Comparative Example 4, the temperature was too high during lactic acid polymerization, which caused some of the synthesized polylactic acid to decompose. The synthesis of organic cages took place in most of the space inside the support. The distribution range of the organic cages, i.e. the active centers, was too wide inside the support, resulting in a significant diffusion effect and poor activity selectivity during the hydrogenation reaction.

[0161] Compared with Example 5, Comparative Example 5 uses a conventional catalyst preparation method. Because the catalyst prepared by the conventional method has a wide size distribution of active centers, the initial activity selectivity of the catalyst is significantly lower than that of the catalyst prepared in Example 5. After 1000 hours, the decrease in activity selectivity is also more obvious than that of the catalyst in Example 5.

[0162] Compared with Example 6, in step (4) of Comparative Example 6, due to the low calcination temperature, polylactic acid cannot be completely decomposed, which blocks the pores of the catalyst. This prevents the reactants from diffusing through the pores, and only a small number of active centers on the outer surface of the catalyst participate in the reaction. The reactants that enter the pores cannot diffuse and flow, resulting in saturated hydrogenation. Therefore, their activity selectivity is very low.

[0163] In Comparative Example 7, because the organic cage existed alone and was not loaded, although there were ceramic balls and screens at the top and bottom of the reactor, the gaps were relatively large. For example, the pore size of a 40-mesh screen reached 0.6 mm, while the size of the organic cage was only in the nm range. Therefore, as soon as material was introduced, the organic cage, along with the palladium active component within it, was carried into the subsequent parts by the material. After 24 hours, there was no catalyst left in the reactor. The hydrogenation rate of acrylic acid was 0.

[0164] The above embodiments are typical examples listed to illustrate the technical solution of the present invention in detail. The present invention shall be subject to the protection scope of the claims and the invention content, and shall not be limited by the described embodiments. Simple substitutions or modifications to the present invention shall still be within the protection scope of the present invention.

Claims

1. An acrylic acid hydrogenation catalyst, characterized in that, The active component includes Pd, and the carrier is silica gel or mainly silica gel; the outer surface of the carrier has an organic cage with a regular structure, and the active component is uniformly loaded in the organic cage, the cage cavity size of which is 2.7 to 3.6 nm. The specific surface area of ​​the acrylic acid hydrogenation catalyst is 50-100 m². 2 / g, based on the mass of the acrylic acid hydrogenation catalyst as 100%, the Pd content is 0.2% to 0.4%; The organic cage is located within 0.08 mm of the outer surface of the carrier extending towards the center; The preparation method of the acrylic acid hydrogenation catalyst includes the following steps: 1) Completely polymerize a hydrophilic polymerizable monomer within the pores of a carrier, ensuring that the resulting polymer does not decompose, and control the polymer to occupy more than 80% of the pore volume of the carrier, to obtain a semi-finished catalyst A. 2) Dissolve tris(4-formylphenyl)amine and the catalyst in a solvent and mix with the semi-finished catalyst A to obtain a mixture; add a solution of an aromatic diamine compound dropwise to the mixture to carry out an aldehyde-amine condensation reaction to form an organic cage-like substance; after the reaction is completed, wash and dry to obtain the semi-finished catalyst B. 3) Under stirring, a solution of the organopalladium compound is added dropwise to the mixture of the semi-finished catalyst B and the alcohol. After the organopalladium compound is fully loaded, the mixture is washed, dried, and calcined at ≤400°C to completely decompose the polymer, yielding the semi-finished catalyst C. 4) Mix the semi-finished catalyst C with a reducing agent. After the palladium is completely reduced, wash and dry to obtain an acrylic acid hydrogenation catalyst. The molar ratio of the tris(4-formylphenyl)amine to the aromatic diamine compound is 1:1.1 to 2.

2. The aromatic diamine compound is selected from 4,4''-diaminotetraphenyl or Rm-substituted 4,4''-diaminotetraphenyl, wherein Rm is selected from at least one of halogens, C1-C5 straight-chain or branched alkyl groups.

2. The acrylic acid hydrogenation catalyst according to claim 1, characterized in that, The mass ratio of palladium to tris(4-formylphenyl)amine in the organopalladium compound is 2 to 14:

1.

3. The acrylic acid hydrogenation catalyst according to claim 1, characterized in that, In step 1), the volume of the hydrophilic polymerizable monomer is 80%-100% of the pore volume of the carrier.

4. The acrylic acid hydrogenation catalyst according to claim 1, characterized in that, In step 1), the hydrophilic polymerizable monomer is selected from organic compounds containing carbonyl, carboxyl, or carbon-carbon double bonds.

5. The acrylic acid hydrogenation catalyst according to claim 1, characterized in that, In step 2), the catalyst is a haloacetic acid; and / or In step 2), the mass ratio of tris(4-formylphenyl)amine to the catalyst is 2000 to 6000:

1.

6. The acrylic acid hydrogenation catalyst according to claim 1, characterized in that, In step 3), the organic palladium compound is selected from palladium acetate or palladium acetylacetonate.

7. The acrylic acid hydrogenation catalyst according to claim 1, characterized in that, In step 4), the semi-finished catalyst C is mixed with the solvent and then mixed with the reducing agent.

8. The acrylic acid hydrogenation catalyst according to claim 3, characterized in that, In step 1), the volume of the hydrophilic polymerizable monomer is 80%-95% of the pore volume of the carrier.

9. The acrylic acid hydrogenation catalyst according to claim 4, characterized in that, In step 1), the hydrophilic polymerizable monomer is selected from acrylic acid, acrylate or lactic acid.

10. The acrylic acid hydrogenation catalyst according to claim 5, characterized in that, In step 2), the catalyst is fluoroacetic acid or chloroacetic acid.

11. The acrylic acid hydrogenation catalyst according to claim 5, characterized in that, In step 2), the catalyst is trifluoroacetic acid or dichloroacetic acid.

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