Selective hydrogenation catalyst and preparation method thereof

Abstract

The invention provides a selective hydrogenation catalyst and a preparation method thereof. The catalyst comprises a carrier, Ag loaded on the carrier, an organic cage loaded on the carrier and Pd loaded in the organic cage, based on 100% of the mass of the carrier, the content of Pd is 0.02-0.04%, the content of Ag is 0.05-0.2%, and the size of the organic cage is 2.7-3.6 nm. The preparation method of the catalyst comprises the following steps: loading a first auxiliary agent Ag on the carrier to obtain a semi-finished product catalyst I; synthesizing a polar polymer on the semi-finished catalyst I to obtain a semi-finished catalyst II; synthesizing an organic cage on the semi-finished catalyst II to obtain a semi-finished catalyst III; and loading Pd in the organic cage of the semi-finished catalyst III to obtain the catalyst. The catalyst contains the organic cage, the active component is loaded in the organic cage, and the active center is narrow in size distribution and appropriate in size.

Description

Technical Field

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

[0002] Ethylene obtained by steam cracking of petroleum hydrocarbons (such as ethane, naphtha, diesel, hydrogenation tail oil, etc.) contains 0.2%-2.5% by mass of acetylene. When used for polymerization, acetylene in ethylene will reduce the activity of the polymerization catalyst and affect the physical properties of the polymer. Therefore, it must be removed. Currently, the industrial method for removing acetylene is generally selective hydrogenation, and the catalysts used are mainly noble metal catalysts such as Pd, Pt, and Au. To ensure that ethylene generated by acetylene hydrogenation and the original ethylene in the raw material do not continue to hydrogenate to form ethane, resulting in ethylene loss, it is necessary to ensure that the catalyst has high hydrogenation selectivity to obtain better economic benefits.

[0003] According to the relative position of the C2 hydrogenation reactor and the demethanizer, C2 hydrogenation is divided into pre-hydrogenation and post-hydrogenation processes. The C2 pre-hydrogenation reactor is before the demethanizer, and the hydrogenation feedstock generally contains C1 fraction, C2 fraction, and C3 fraction. In addition to hydrogen and methane in the C1 fraction, there is also CO. Generally, the feedstock composition of pre-depropane pre-hydrogenation includes: H 2 15%-30%, methane 15-30%, C 2 H 6 4%-10%, C 2 H 4 25%-40%, C 2 H 2 0.4%-0.7%, C 3 H 6 8%-11%, C 3 H 8 1%-2%, propyne 0.1%-0.6%, allene 0.1%-0.6%, CO 0.04%-0.14%.

[0004] During the selective hydrogenation process, the hydrogenation dimerization reaction of acetylene easily occurs to generate C4 fraction, and the C4 fraction further polymerizes to form oligomers with a wide molecular weight range, commonly known as "green oil". Green oil adsorbs on the catalyst surface and further forms coke, blocking the catalyst pores, so that the reactants cannot diffuse to the surface of the catalyst active center, resulting in a decrease in catalyst activity.

[0005] Noble metal catalysts have high activity, but during use, they are prone to generating green oil, causing the catalyst to coke and deactivate, which affects the stability and service life of the catalyst. CN101664682A discloses a non-noble metal supported selective hydrogenation catalyst, its preparation method and application, including a carrier and a main active component and a promoter component supported on the carrier. Among them, the main active component is Ni, and the promoter component is selected from at least one of Mo, La, Ag, Bi, Cu, Nd, Cs, Ce, Zn, and Zr. The main active component and the promoter component both exist in an amorphous state, with an average particle size <10 nm. The carrier is a non-oxidizing porous material; and the catalyst is prepared by the microemulsion method.

[0006] CN101433845A discloses an unsaturated hydrocarbon selective hydrogenation catalyst and its preparation method. This catalyst uses alumina as the carrier and palladium as the active component, and improves the anti-impurity and anti-coking performance of the catalyst by adding rare earth, alkaline earth metals, and fluorine, but the selectivity of its catalyst is not ideal.

[0007] The catalysts prepared by the above methods all use catalysts with a single pore size distribution. During the fixed-bed reaction process, affected by internal diffusion, the selectivity of the catalyst is poor. A carrier with a bimodal pore distribution, while ensuring high activity of the catalyst, the presence of macropores can reduce the influence of internal diffusion and improve the selectivity of the catalyst. CN101433842A discloses a hydrogenation catalyst with a bimodal pore distribution. The most probable radius of the small pore part is 2 - 50 nm, and the most probable radius of the macropore part is 100 - 500 nm. Due to the bimodal pore distribution of the catalyst, it has good hydrogenation activity and good selectivity, and a large ethylene increment.

[0008] In the C2 hydrogenation reaction, the generation of green oil and the coking of the catalyst are important factors affecting the service life of the catalyst. The activity, selectivity, and service life of the catalyst constitute the overall performance of the catalyst. The methods listed above either propose good ways to improve the activity and selectivity of the catalyst, but do not solve the problem of easy coking of the catalyst, or solve the problems of easy generation of green oil and coking of the catalyst, but do not solve the problem of selectivity. Although a carrier with a macroporous structure can improve selectivity, larger molecules generated by polymerization and chain growth reactions are also likely to accumulate in the macropores of the carrier, causing the catalyst to coke and deactivate, affecting the service life of the catalyst.

[0009] In the C2 selective hydrogenation reaction, when Pd is the main active component, during the traditional impregnation process for preparing the catalyst, Pd exists as Pd 2+ or [PdCl 4 2- ​Combined with the carrier in the form of ions, during the activation process, Pd aggregates to form active centers. Since the aggregation of Pd during the activation process is a random process dominated by kinetics, that is to say, it is very difficult to control the size of each active center in advance.

[0010] Previous studies have found that in the process of selective hydrogenation of acetylene, the process is as follows: First, an acetylene molecule combines with 1 hydrogen atom to form a vinyl group, and the vinyl group then combines with a hydrogen atom to form ethylene, or 2 vinyl groups couple to form butadiene. Since butadiene can undergo a series of polymerization reactions to form green oil and then form coke, therefore, inhibiting the formation of butadiene has become the key to preventing coking of the carbon dioxide selective hydrogenation catalyst.

[0011] Obviously, if 2 vinyl groups are formed simultaneously on 1 catalyst active center, the probability of forming butadiene will increase greatly. The research also found that the larger the size of the active center, the higher the yield of butadiene. Generally, there are two ways to prevent the large size of the active center: one is to reduce the amount of the active component, and the other is to expand the dispersion area of the active component. However, reducing the loading amount of the active component may result in insufficient active centers, leading to insufficient hydrogenation activity, inability to completely remove acetylene, unqualified hydrogenation products, and extremely large economic losses.

[0012] With the expansion of the loading area of the active component, some of the active centers are not located close to the surface of the catalyst, resulting in low selectivity of the catalyst and large ethylene loss during the hydrogenation process.

[0013] To prepare a catalyst with a narrow particle size distribution, some researchers have synthesized a series of organic cages with three-dimensional structures in recent years. In the paper "Three-dimensional hydrophobic porous organic polymers confined Pdnanoclusters for phase-transfer catalytic hydrogenation of nitroarenes inwater", it is disclosed that an organic three-dimensional organic cage was synthesized using precursors such as tris(4-formylphenyl)amine. Palladium metal was loaded into the synthesized organic cage and used for the hydrogenation of nitrobenzene in the liquid phase to prepare aniline. The catalyst preparation steps in this literature include two steps. First, tris(4-formylphenyl)amine was mixed with haloacetic acid, dissolved in a haloalkane, stirred, and a mixed solution of an aromatic diamine compound and a haloalkane was added dropwise. The mixture was allowed to stand. After the reaction was complete, the residual liquid was poured out and washed with alcohol and deionized water respectively to obtain an organic cage. The pore sizes of the cage were 1.25 nm and 1.27 nm for 3D-HPOPs-1 and 1.47 nm and 1.84 nm for 3D-HPOPs-2. Then, an organopalladium salt was dissolved in an organic solvent to obtain a palladium precursor solution. The organic cage was immersed in an alcohol solution, and the palladium precursor solution was added dropwise to the mixture of the organic cage and alcohol while stirring. After the addition of the palladium precursor solution was completed, it was allowed to stand, the solution was poured out, and dried to obtain the catalyst. However, the size of the organic cage prepared by this method is not suitable for gas-phase selective hydrogenation reactions.

[0014] CN114160196A discloses a method for preparing a cluster Pd catalyst. This preparation method first uses trimesic aldehyde and (1R,2R)-cyclohexanediamine as raw materials to synthesize an organic molecular cage. Then, AT-RCC3 organic molecular cage is synthesized by reacting RCC3 with acetone, and FT-RCC3 organic molecular cage is synthesized by reacting RCC3 with paraformaldehyde. Then, Pd clusters are loaded by the cavity confinement effect of RCC3, AT-RCC3, and FT-RCC3 molecular cages to prepare Pd@RCC3, Pd@AT-RCC3, and Pd@FT-RCC3 catalysts with adjustable Pd cluster sizes. The sizes of the cavities of the prepared Pd@RCC3, Pd@AT-RCC3, and Pd@FT-RCC3 are 0.7, 0.67, and 0.4 nm respectively. However, the size of the organic cage prepared by this method is not suitable for gas-phase selective hydrogenation reactions.

[0015] These organic cages have fixed sizes and can be used to immobilize metals, thereby preparing catalysts with highly dispersed metal clusters. Currently, after these three-dimensional organic cages are loaded with active components, they can be used for full hydrogenation or homogeneous hydrogenation. For selective hydrogenation, not only does the size of the active center affect the reaction, but also the distribution of the active components in the catalyst has a great impact on the reaction results. A catalyst with a uniform distribution of active components is not suitable for selective hydrogenation reactions. If the organic cages loaded with active components are uniformly distributed within the carrier, they can only be used for liquid-phase saturated hydrogenation or phase-transfer catalytic hydrogenation, but not for gas-phase selective hydrogenation. The reason is that gas-phase selective hydrogenation is a reaction limited by internal diffusion and requires the active centers to be located on the outer layer of the catalyst.

[0016] Currently, there are many studies on noble metal single-atom catalysts in hydrogenation reactions. However, for the hydrogenation of alkynes, there is still a significant gap between such catalysts and practical applications. The reasons are as follows: At the active center of the hydrogenation reaction, two processes need to be completed. The first is the activation of the alkyne molecule, that is, the electron pair of the double bond of the alkyne molecule enters the empty orbital of the active center atom, and the active center atom then feeds back the electron pair to the antibonding orbital of the alkyne molecule, resulting in a decrease in the double bond energy, activation of the double bond, and cleavage. The second is that the hydrogen molecule also needs the same process to be activated into hydrogen atoms. For a single-atom active center, due to the limited physical size of a single atom, it is difficult to complete these two processes simultaneously, so the reaction process is slow and difficult to meet the requirements of practical applications. Therefore, it is natural that the active center needs to have a certain physical size. In fact, for palladium catalysts, since a large amount of hydrogen can be absorbed inside their stacking structures, the activation of hydrogen and the transfer of hydrogen atoms are completed within the stacking structure of palladium, so its activity is higher than that of active components that can only adsorb hydrogen on the surface.

[0017] In summary, developing a new type of selective hydrogenation catalyst and its preparation method remains one of the urgent problems to be solved in this field. Summary of the Invention

[0018] To solve the above technical problems, the object of the present invention is to provide a selective hydrogenation catalyst and its preparation method. The selective hydrogenation catalyst of the present invention can be used as a selective hydrogenation catalyst for C1-C3 fractions, contains organic cages, and has active components loaded in the organic cages, with a narrow size distribution and appropriate size of the active centers.

[0019] To achieve the above object, a first aspect of the present invention provides a selective hydrogenation catalyst, which comprises a carrier, a first promoter Ag supported on the carrier, an organic cage supported on the carrier, and an active component Pd supported in the organic cage; wherein, based on the mass of the carrier being 100%, the content of Pd is 0.02-0.04%, the content of Ag is 0.05-0.2%, and the size of the organic cage is 2.7-3.6 nm.

[0020] According to a specific embodiment of the present invention, preferably, the selective hydrogenation catalyst further comprises a second promoter Cu supported on the carrier, and based on the mass of the carrier being 100%, the content of Cu is 1-5%.

[0021] According to a specific embodiment of the present invention, preferably, the specific surface area of the selective hydrogenation catalyst is 1-15 m 2 / g.

[0022] According to a specific embodiment of the present invention, preferably, the selective hydrogenation catalyst is prepared by at least the following steps:

[0023] (1) Loading a first promoter Ag on the carrier to obtain a semi-finished catalyst I;

[0024] (2) Synthesizing a polar polymer on the semi-finished catalyst I obtained in step (1), and the polar polymer occupies 70-95% of the pore volume of the carrier to obtain a semi-finished catalyst II;

[0025] (3) Synthesizing an organic cage on the semi-finished catalyst II obtained in step (2) to obtain a semi-finished catalyst III;

[0026] (4) Loading a palladium active component in the organic cage of the semi-finished catalyst III obtained in step (3) to obtain the selective hydrogenation catalyst.

[0027] A second aspect of the present invention provides a preparation method of a selective hydrogenation catalyst, which comprises the following steps:

[0028] (1) Loading a first promoter Ag on the carrier to obtain a semi-finished catalyst I;

[0029] (2) Synthesizing a polar polymer on the semi-finished catalyst I obtained in step (1), and the polar polymer occupies 70-95% of the pore volume of the carrier to obtain a semi-finished catalyst II;

[0030] (3) Synthesizing an organic cage on the semi-finished catalyst II obtained in step (2) to obtain a semi-finished catalyst III;

[0031] (4) Palladium active components are loaded into the organic cages of the semi-finished catalyst III obtained in step (3) to obtain the selective hydrogenation catalyst described above.

[0032] According to the specific embodiments of the present invention, preferably, in step (1), the carrier includes one or a combination of several of silica, zinc oxide, magnesium oxide, alumina, titanium oxide, etc. More preferably, the carrier is a calcined carrier, and the specific surface area of the calcined carrier is 1-15 m 2 / g. The temperature and time for calcining the carrier can be routinely adjusted by those skilled in the art according to the actual situation.

[0033] According to the specific embodiments of the present invention, preferably, in step (1), based on the mass of the carrier being 100%, the loading amount of Ag is 0.05-0.2%.

[0034] According to the specific embodiments of the present invention, preferably, step (1) specifically includes: impregnating the calcined carrier in an aqueous solution containing a silver salt, and after the solution is completely absorbed, standing for a period of time, and at least drying and calcining to obtain the semi-finished catalyst I. More preferably, the standing time is 2-12 hours. More preferably, the calcination temperature is 500-600 °C and the time is 2-6 hours. The silver salt is a water-soluble silver salt, and specific compounds can be routinely selected by those skilled in the art, such as silver nitrate, etc.

[0035] According to the specific embodiments of the present invention, preferably, in step (2), the polar polymer occupies 75-95% of the pore volume of the carrier.

[0036] According to the specific embodiments of the present invention, preferably, in step (2), the polar polymer includes polyacrylic acid and / or polylactic acid, etc.

[0037] According to the specific embodiments of the present invention, preferably, step (2) specifically includes: mixing a hydrophilic polymer monomer with the semi-finished catalyst I, and carrying out a polymerization reaction to obtain the semi-finished catalyst II, and the polar polymer occupies 70-95% (preferably 75-95%) of the pore volume of the carrier. More preferably, the hydrophilic polymer monomer includes acrylic acid and / or lactic acid. Those skilled in the art can obtain the mixing ratio of the hydrophilic polymer monomer and the semi-finished catalyst I based on the proportion of the polar polymer occupying the pore volume of the carrier, and the present invention does not further limit this ratio.

[0038] In some specific embodiments, preferably, in step (2), when the polar polymer is polyacrylic acid, the hydrophilic polymerizable monomer is acrylic acid, the polymerization reaction is carried out in the presence of an initiator, the temperature of the polymerization reaction is 80 - 90 °C, and the time is 1 - 3 hours. More preferably, when the polar polymer is polyacrylic acid, a controller is further included in the reaction system of the polymerization reaction, and the controller includes alkali metal hypophosphite and / or water-soluble copper salt, etc. Specifically, the controller may include potassium hypophosphite and / or copper acetate, etc. The controller has the function of controlling the polymerization reaction to generate only water-soluble acrylic polymer. The dosage ratios of the initiator and the controller to the monomer acrylic acid can be routinely adjusted by those skilled in the art.

[0039] In other specific embodiments, preferably, in step (2), when the polar polymer is polylactic acid, the hydrophilic polymerizable monomer is lactic acid, the temperature of the polymerization reaction is 120 - 190 °C, and the time is 2 - 15 hours.

[0040] According to the specific embodiments of the present invention, preferably, step (3) specifically includes: mixing tris(4-formylphenyl)amine with haloacetic acid in haloalkane to obtain a mixed solution; then mixing the mixed solution with the semi-finished catalyst II, and dropwise adding a mixed solution of aromatic diamine compound and haloalkane under stirring conditions. After the dropping is completed, let it stand for a period of time. After the reaction is complete, the obtained product is washed and dried at least, and the semi-finished catalyst III is obtained.

[0041] According to the specific embodiments of the present invention, preferably, in step (3), the mass ratio of tris(4-formylphenyl)amine to the haloacetic acid is 1000 - 3000:1.

[0042] According to the specific embodiments of the present invention, preferably, in step (3), the molar ratio of the aromatic diamine compound to tris(4-formylphenyl)amine is 1.3 - 2.0:1.

[0043] According to the specific embodiments of the present invention, preferably, in step (3), the haloacetic acid includes trifluoroacetic acid and / or dichloroacetic acid, etc.

[0044] According to the specific embodiments of the present invention, preferably, in step (3), the aromatic diamine compound includes diamine compounds containing quaterphenyl. More preferably, the aromatic diamine compound includes one or a combination of several of 4,4”-diaminoterphenyl, halogenated 4,4”-terphenyl diamine, and alkyl-substituted 4,4”-terphenyl diamine, etc.

[0045] According to the specific embodiments of the present invention, preferably, in step (3), the standing time is 50 - 200 hours.

[0046] According to a specific embodiment of the present invention, preferably, in step (3), the size of the organic cage in the semi-finished catalyst III is 2.7 - 3.6 nm.

[0047] According to a specific embodiment of the present invention, preferably, step (4) specifically includes: immersing the semi-finished catalyst III in an alcohol, dropping a palladium precursor solution into it under stirring conditions, after standing for a period of time, and then obtaining the selective hydrogenation catalyst after at least drying and calcination, and the palladium active component is loaded in the organic cage. Among them, the alcohol used may include, but is not limited to, ethanol and / or methanol, etc.

[0048] According to a specific embodiment of the present invention, preferably, in step (4), the palladium precursor solution includes a solution of an organic palladium salt in an organic solvent. More preferably, the organic palladium salt includes palladium acetate and / or palladium acetylacetonate, etc. The organic solvent for dissolving the organic palladium salt can be conventionally selected by those skilled in the art.

[0049] According to a specific embodiment of the present invention, preferably, in step (4), the mass ratio of palladium in the palladium precursor solution to the tris(4-formylphenyl)amine is 1.5 - 10:1.

[0050] According to a specific embodiment of the present invention, preferably, step (4) further includes: after the palladium precursor solution is dropped and left standing for a period of time, a reducing agent is added. The reducing agent used includes, but is not limited to, one or a combination of hydrazine hydrate, formic acid, formaldehyde, methanol, ethanol, and acetaldehyde, etc. The reducing agent can be added in the form of an aqueous solution of the reducing agent, and the mass concentration of the aqueous solution of the reducing agent can be conventionally adjusted by those skilled in the art, for example, 5 - 50%. More preferably, the reducing agent includes hydrazine hydrate. The ratio of the reducing agent to the palladium salt can be conventionally adjusted by those skilled in the art, and generally an excessive amount of the reducing agent is used. The present invention preferably uses the liquid-phase in-situ reduction method, and the reducing agent can reduce palladium to palladium atoms, which is beneficial to the loading of palladium in the organic cage. Among them, more preferably, after adding the reducing agent, it can be stirred for a period of time, the stirring temperature can be room temperature - 60 °C, and the time can be 10 - 200 minutes.

[0051] According to a specific embodiment of the present invention, preferably, in step (4), the standing time is 1 - 4 hours.

[0052] According to the specific embodiments of the present invention, preferably, in step (4), the calcination temperature is from the decomposition temperature of the polar polymer to below 450 °C. More preferably, the calcination temperature is from the decomposition temperature of the polar polymer to below 430 °C. This calcination process is carried out above the decomposition temperature of the polar polymer so that the polar polymer can be fully decomposed. Further preferably, the calcination time is 2 - 6 hours.

[0053] According to the specific embodiments of the present invention, preferably, in step (4), when the polar polymer is polyacrylic acid, the calcination temperature is 250 - 450 °C (preferably 250 - 430 °C); when the polar polymer is polylactic acid, the calcination temperature is 200 - 450 °C (preferably 200 - 430 °C).

[0054] According to the specific embodiments of the present invention, preferably, the above preparation method further includes step (5) after step (4): loading a second auxiliary agent Cu on the product obtained in step (4) to obtain the selective hydrogenation catalyst.

[0055] According to the specific embodiments of the present invention, preferably, step (5) specifically includes: impregnating the product obtained in step (4) in an aqueous solution containing a copper salt, and after the solution is completely absorbed, standing for a period of time, and then obtaining the selective hydrogenation catalyst after at least drying. More preferably, the standing time is 2 - 12 hours. The copper salt is a water-soluble copper salt, and specific compounds can be conventionally selected by those skilled in the art, such as a combination of one or more of copper nitrate, copper sulfate, and copper chloride, etc.

[0056] According to the specific embodiments of the present invention, preferably, step (5) further includes: impregnating the product obtained in step (4) in an aqueous solution containing a copper salt, and after the solution is completely absorbed, standing for a period of time, then adding a reducing agent, stirring for a period of time, and then obtaining the selective hydrogenation catalyst after at least the above drying. The reducing agents used include, but are not limited to: a combination of one or more of hydrazine hydrate, formic acid, formaldehyde, methanol, ethanol, and acetaldehyde, etc. The reducing agent can be added in the form of an aqueous solution of the reducing agent, and the mass concentration of the aqueous solution of the reducing agent can be conventionally adjusted by those skilled in the art, such as 5 - 50%. More preferably, the reducing agent includes a combination of one or more of hydrazine hydrate, formic acid, and formaldehyde, etc. The ratio of the reducing agent to the copper salt can be conventionally adjusted by those skilled in the art, and generally an excessive amount of the reducing agent is used. The present invention preferably adopts the liquid-phase in-situ reduction method, and the reducing agent can reduce copper to copper atoms, which is beneficial to improving the activity of copper. Among them, more preferably, the temperature for stirring after adding the reducing agent is room temperature - 60 °C, and the time is 10 - 200 minutes.

[0057] According to the specific embodiments of the present invention, preferably, in step (5), if no reducing agent is used, calcination is carried out after the drying, the temperature of the calcination is 350 - 450 °C, and the time is 2 - 6 hours. If a reducing agent is used, the step of calcination can be omitted.

[0058] According to the specific embodiments of the present invention, preferably, in step (5), based on the mass of the carrier being 100%, the loading amount of Cu is 1 - 5%. In the pre-hydrogenation reaction of C2, in addition to the hydrogenation dimerization of acetylene to produce by-product butadiene, the hydroformylation reaction occurs between CO and olefins to produce by-products such as propionaldehyde. These by-products have a stronger adsorption ability on the surface of the carrier and are more likely to cause catalyst deactivation. Therefore, the catalyst of the present invention may further include a second promoter Cu. The role of Cu is to hydrogenate such carbonyl-containing compounds to produce alcohols, etc., and avoid the condensation of these carbonyl groups to form larger molecules.

[0059] The present invention also provides a selective hydrogenation catalyst prepared by the above preparation method.

[0060] The present invention provides a selective hydrogenation catalyst and a preparation method thereof. The catalyst of the present invention is applicable to the pre-hydrogenation process of C2 and can be used as a selective hydrogenation catalyst for C1 - C3 fractions. In the preparation process of the catalyst of the present invention, by synthesizing a polar polymer to occupy most of the pore volume of the carrier, especially the internal pores of the carrier, and then in-situ synthesizing an organic cage with a regular structure in the external pores and / or on the external surface of the carrier. The size of the cage is 2.7 - 3.6 nm, and the palladium active component is loaded in these organic cages, and finally the catalyst of the present invention is obtained. Limited by the size of the organic cage synthesized in the present invention, the size distribution of the active centers is narrow, the size is appropriate, and the size is uniform. Compared with the prior art, since the situation of large active centers is avoided, the hydrogenation dimerization is not likely to occur, and the probability of simultaneously adsorbing olefins and CO is greatly reduced. Also, the problem that some active centers are too small and have no activity under conventional reaction conditions, resulting in waste of some precious metals, is avoided. The size of the active centers for acetylene hydrogenation is 2 - 4 nm, and the size of the active centers of the present invention can just be controlled within this range. Therefore, the catalyst of the present invention can not only meet the activity requirements, but also has no overly large active centers, greatly reducing the probability of simultaneously adsorbing olefins and CO during the acetylene hydrogenation process, and is not likely to undergo hydrogenation dimerization.

[0061] In the selective hydrogenation catalyst provided by the present invention, since palladium is loaded in the organic cage, restricted by the physical size of the cage, the active center composed of palladium has a maximum size of the cage size, reducing the active centers with an aggregation size greater than 3.0 nm. This size meets the requirements for acetylene selective hydrogenation activity, and the probability of simultaneously forming 2 vinyl groups or the simultaneous adsorption of CO and olefins at one active center is greatly reduced, reducing the probability of hydroformylation reaction, delaying the catalyst deactivation rate, the yield of butene can be reduced to less than 1 / 2 of that of the traditional catalyst, and the generation amount of oxygen-containing compounds such as aldehydes is also significantly reduced. Moreover, the organic cage is located in the outer pores and / or outer surface of the catalyst, avoiding the influence of internal diffusion limitation on the catalytic reaction, and the selectivity of the catalyst is very good. Using the catalyst of the present invention can reduce the generation amount of C4 by-products, and the carbonyl hydrogenation of oxygen-containing compounds reduces the generation amount of macromolecular oxygen-containing compounds. In the present invention, a calcination temperature below 450 °C is adopted during the calcination process after synthesizing the organic cage, and the organic cage structure will not be damaged. At the same time, the catalyst of the present invention is applicable to the pre-hydrogenation process of C2, and since the catalyst in the pre-hydrogenation process of C2 generally does not need to be regenerated, the catalyst of the present invention can be used effectively for a long time.

[0062] The technical solution of the present invention has at least the following beneficial effects:

[0063] (1) The operation cycle of the catalyst is greatly extended

[0064] Restricted by the physical size of the cage, the active center composed of palladium has a maximum size of the cage size, avoiding the active centers with an aggregation size greater than 4.0 nm and reducing the active centers with an aggregation size greater than 3.0 nm. The probability of simultaneously forming 2 vinyl groups or the simultaneous adsorption of CO and olefins at one active center is greatly reduced, reducing the probability of hydroformylation reaction, delaying the catalyst deactivation rate, the yield of butene can be reduced to less than 1 / 2 of that of the traditional catalyst, and the generation amount of oxygen-containing compounds such as aldehydes is also significantly reduced.

[0065] (2) The catalyst cost is effectively reduced

[0066] Restricted by the physical size of the cage, the active centers with an aggregation size less than 2.0 nm are avoided or reduced, and these active centers have no activity in the presence of CO. Since the number of these inactive active centers is avoided or reduced, the catalyst cost is reduced. Description of the Drawings

[0067] Figure 1 It is the structural diagram of the organic cage prepared in Example 1. Detailed Embodiments

[0068] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0069] The analytical test methods used in the following examples and comparative examples include:

[0070] Specific surface area and pore size: Referring to the method described in GB / T-5816, the catalyst specific surface area and organic cage pore size were measured using a BET tester (Micah Company, USA). It should be noted that the pore size of the organic cage needs to be synthesized separately (not loaded on a carrier) and then tested.

[0071] Content of active components and additives in the catalyst: Atomic absorption spectrometry was used to determine the content of Pd, Ag, and Cu (if contained) in the catalyst using an A240FS atomic absorption spectrometer.

[0072] Acetylene conversion, ethylene selectivity and C4 production: Agilent 7890A gas chromatograph was used to detect the hydrogen, acetylene and butene contents at the outlet and inlet of the hydrogenation reactor.

[0073] Acetylene conversion and ethylene selectivity are calculated according to the following formula:

[0074] Acetylene conversion rate (%) = 100 × △ acetylene / inlet acetylene content;

[0075] Ethylene selectivity (%) = 100 × Δethylene / Δacetylene.

[0076] Catalyst weight: The catalyst weight was measured using a 0.1 mg electronic balance.

[0077] The raw materials used in the following examples and comparative examples include: tri(4-formylphenyl)amine (CAS No.: 119001-43-3), trifluoroacetic acid, dichloroacetic acid, dichloroethane, 4,4"-diaminoquaternaryl (CAS No.: 53693-67-7), 2-chloro-4,4"-diaminoquaternaryl (prepared by conventional chlorination of 4,4"-diaminoquaternaryl), 2-ethyl-4,4"-diaminoquaternaryl (prepared by conventional chlorination of 4,4"-diaminoquaternaryl Method for alkylation), 2-fluoro-4,4"-diaminoquaternaryl (prepared by conventional fluorination of 4,4"-diaminoquaternaryl), 3-methyl-4,4"terphenylenediamine (prepared by conventional alkylation of 4,4"terphenylenediamine), hydrazine hydrate, ethanol, methanol, formic acid, formaldehyde, lactic acid, acrylic acid, palladium acetate, palladium acetylacetonate, silver nitrate, copper nitrate. All the above raw materials were analytical grade and were purchased from Shanghai Sinopharm Group Co., Ltd.; alumina was purchased from Shandong Aluminum Group Co., Ltd.

[0078] Example 1

[0079] This embodiment provides a selective hydrogenation catalyst, wherein:

[0080] Support: A commercially available spherical alumina-titania support is used, wherein the mass content of alumina is 70%, and the diameter of the support is 4 mm. After calcination at 1250 °C for 4 h, the water absorption rate is 0.35, and the specific surface area is 1 m 2 / g. Weigh 100 g of the calcined support.

[0081] Preparation of the catalyst:

[0082] (1) Dissolve 0.079 g of silver nitrate in 35 ml of deionized water to obtain an aqueous solution containing silver salt. Immerse 100 g of the calcined support in the aqueous solution containing silver salt. After the solution is completely absorbed, let it stand for 2 hours, dry at 120 °C, and calcine at 500 °C for 4 hours to obtain semi-finished catalyst I;

[0083] (2) Take 28.61 g of an aqueous acrylic acid solution containing 30% (mass fraction) of water, 0.01 g of potassium hypophosphite monohydrate, 0.01 g of copper acetate monohydrate, and 0.12 ml of 30% (mass fraction) hydrogen peroxide as an initiator. After mixing evenly, a mixed solution containing acrylic acid is obtained; Immerse semi-finished catalyst I in the mixed solution. After the solution is completely absorbed, transfer it to a reflux flask, heat it to 80 °C under stirring conditions, and react at a constant temperature for 2 hours to obtain semi-finished catalyst II; Polyacrylic acid occupies 75% of the pore volume of the support;

[0084] (3) Weigh 13.3 mg of tris(4-formylphenyl)amine and 0.013 mg of trichloroacetic acid, dissolve them in 40 ml of dichloroethane, then mix with semi-finished catalyst II, stir and dropwise add a mixed solution of 0.024 g of 4,4”-diaminoterphenyl and 10 ml of trichloroethane. After the dropping is completed, let the mixture stand at room temperature for 200 hours, pour out the residual liquid, wash the obtained product with ethanol and deionized water respectively, and then dry to obtain semi-finished catalyst III;

[0085] (4) Dissolve 0.057 g of palladium acetylacetonate in 50 ml of toluene. Wait until the palladium acetylacetonate is completely dissolved to obtain a palladium acetylacetonate solution; Immerse semi-finished catalyst III in 40 ml of ethanol to obtain an ethanol solution containing semi-finished catalyst III; Under stirring conditions, dropwise add the palladium acetylacetonate solution to the ethanol solution containing semi-finished catalyst III. After the dropping is completed, let it stand for 4 hours, pour out the residual liquid, wash the obtained product with deionized water, then dry at 120 °C, and then calcine at 280 °C for 2 hours to obtain the said selective hydrogenation catalyst.

[0086] After detection, the selective hydrogenation catalyst of this embodiment includes a carrier, a first promoter Ag supported on the carrier, an organic cage supported on the carrier, and an active component Pd supported in the organic cage.

[0087] In the catalyst obtained by atomic absorption spectrometry, based on the mass of the carrier being 100%, the content of Pd is 0.02% and the content of Ag is 0.05%.

[0088] The maximum pore diameter of the organic cage in this embodiment measured by the BET method is 3.53 nm, and the minimum pore diameter is 2.91 nm. The structural diagram of the organic cage is as Figure 1 shown.

[0089] The specific surface area of the catalyst measured by the BET method is 1 m 2 / g.

[0090] Comparative Example 1

[0091] Carrier: The same carrier as in Example 1 is used.

[0092] Catalyst preparation: The preparation conditions are basically the same as those in Example 1, except that Ag is not loaded.

[0093] (1) Take 28.61 g of an aqueous acrylic acid solution containing 30% (mass fraction) of water, 0.01 g of potassium hypophosphite monohydrate, 0.01 g of copper acetate monohydrate, and 0.12 ml of 30% (mass fraction) hydrogen peroxide as an initiator. After mixing evenly, a mixed solution containing acrylic acid is obtained; 100 g of the calcined carrier is impregnated in this mixed solution. After the solution is completely absorbed, it is transferred to a reflux flask and heated to 80°C under stirring conditions, and the reaction is kept at a constant temperature for 2 hours to obtain a semi-finished catalyst B1; Polyacrylic acid occupies 75% of the pore volume of the carrier;

[0094] (2) Weigh 13.3 mg of tris(4-formylphenyl)amine and 0.013 mg of trichloroacetic acid, dissolve them in 40 ml of dichloroethane, then mix them with the semi-finished catalyst B1, stir and add dropwise a mixed solution of 0.024 g of 4,4”-diaminoterphenyl and 10 ml of trichloroethane. After the addition is complete, the mixture is left standing at room temperature for 200 hours, the residual liquid is poured out, and the obtained product is washed with ethanol and deionized water respectively, and then dried to obtain a semi-finished catalyst C1;

[0095] (3) Dissolve 0.057 g of palladium acetylacetonate in 50 ml of toluene. After the palladium acetylacetonate is completely dissolved, a palladium acetylacetonate solution is obtained; immerse the semi-finished catalyst C1 in 40 ml of ethanol to obtain an ethanol solution containing the semi-finished catalyst C1; under stirring conditions, drop the palladium acetylacetonate solution into the ethanol solution containing the semi-finished catalyst C1. After the dropping is completed, let it stand for 4 hours, pour off the residual liquid, wash the obtained product with deionized water, then dry it at 120 °C and calcine it at 280 °C for 2 hours to obtain the selective hydrogenation catalyst.

[0096] In the catalyst obtained by atomic absorption spectrometry, based on the mass of the carrier being 100%, the content of Pd is 0.02%.

[0097] The specific surface area of the catalyst obtained by BET method is 1 m 2 / g.

[0098] Example 2

[0099] This example provides a selective hydrogenation catalyst, wherein:

[0100] Carrier: Use a commercially available cylindrical alumina carrier with a diameter of 3.5×3.5 mm. After calcination at 1190 °C for 4 h, the water absorption rate is 0.45 and the specific surface area is 7 m 2 / g. Weigh 100 g of the calcined carrier.

[0101] Catalyst preparation:

[0102] (1) Dissolve 0.142 g of silver nitrate in 45 ml of deionized water to obtain an aqueous solution containing silver salt. Immerse 100 g of the calcined carrier in the aqueous solution containing silver salt. After the solution is completely absorbed, let it stand for 12 hours, dry it at 120 °C and calcine it at 550 °C for 4 hours to obtain the semi-finished catalyst I;

[0103] (2) Take 45.36 g of lactic acid and mix it with the semi-finished catalyst I, and react at a constant temperature of 190 °C for 15 hours to obtain the semi-finished catalyst II; the polylactic acid occupies 80.0% of the pore volume of the carrier;

[0104] (3) Weigh 3 mg of tris(4-formylphenyl)amine and mix it with 0.0015 mg of dichloroacetic acid, dissolve them in 50 ml of dichloroethane, then mix them with the semi-finished catalyst II, stir and drop a mixed solution of 6.08 mg of 4,4”-diaminoterphenyl and 10 ml of dichloroethane. After the dropping is completed, let the mixture stand at room temperature for 50 hours, pour out the residual liquid, wash the obtained product with ethanol and deionized water respectively, and then dry it to obtain the semi-finished catalyst III;

[0105] (4) Dissolve 0.086 g of palladium acetylacetonate in 50 ml of chloroform. Wait until the palladium acetylacetonate is completely dissolved to obtain a palladium acetylacetonate solution. Immerse the semi-finished catalyst III in 50 ml of ethanol to obtain an ethanol solution containing the semi-finished catalyst III. Under stirring conditions, drop the palladium acetylacetonate solution into the ethanol solution containing the semi-finished catalyst III. After the dropping is completed, let it stand for 4 hours, pour off the residual liquid, wash the obtained product with deionized water, then dry it at 120 °C and calcine it at 350 °C for 5 hours to obtain the selective hydrogenation catalyst.

[0106] After testing, the selective hydrogenation catalyst of this example includes a support, a first auxiliary agent Ag supported on the support, an organic cage supported on the support, and an active component Pd supported in the organic cage.

[0107] In the catalyst obtained by atomic absorption spectrometry, based on the mass of the support being 100%, the content of Pd is 0.03% and the content of Ag is 0.09%.

[0108] The maximum pore diameter of the organic cage in this example measured by the BET method is 3.60 nm, and the minimum pore diameter is 2.74 nm.

[0109] The specific surface area of the catalyst obtained by the BET method is 7 m 2 / g.

[0110] Comparative Example 2

[0111] This comparative example provides a selective hydrogenation catalyst, wherein:

[0112] Support: The same support as in Example 2 is used.

[0113] Catalyst preparation: The preparation conditions are the same as in Example 2, except that the volume of polylactic acid is 40% of the pore volume of the support.

[0114] (1) Dissolve 0.142 g of silver nitrate in 45 ml of deionized water to obtain an aqueous solution containing a silver salt. Immerse 100 g of the calcined support in the aqueous solution containing the silver salt. After the solution is completely absorbed, let it stand for 12 hours, dry at 120 °C, and calcine at 550 °C for 4 hours to obtain a semi-finished catalyst A2;

[0115] (2) Take 22.68 g of lactic acid and mix it with the semi-finished catalyst A2, and react at a constant temperature of 190 °C for 15 hours to obtain a semi-finished catalyst B2; The polylactic acid occupies 40% of the pore volume of the support;

[0116] (3) Weigh 3 mg of tris(4-formylphenyl)amine and mix it with 0.0015 mg of dichloroacetic acid, dissolve them in 50 ml of dichloroethane, then mix with semi-finished catalyst B2, stir and dropwise add a mixed solution of 6.08 mg of 4,4”-diaminoterphenyl and 10 ml of dichloroethane. After the addition is complete, let the mixture stand at room temperature for 50 hours, pour out the residual liquid, wash the obtained product with ethanol and deionized water respectively, and then dry it to obtain semi-finished catalyst C2;

[0117] (4) Dissolve 0.086 g of palladium acetylacetonate in 50 ml of chloroform. Wait until the palladium acetylacetonate is completely dissolved to obtain a palladium acetylacetonate solution; Immerse semi-finished catalyst C2 in 50 ml of ethanol to obtain an ethanol solution containing semi-finished catalyst C2; Under stirring conditions, dropwise add the palladium acetylacetonate solution to the ethanol solution containing semi-finished catalyst C2. After the addition is complete, let it stand for 4 hours, pour out the residual liquid, wash the obtained product with deionized water, then dry it at 120 °C and calcine it at 350 °C for 5 hours to obtain the said selective hydrogenation catalyst.

[0118] In the catalyst obtained by atomic absorption spectrometry, based on the mass of the carrier being 100%, the content of Pd is 0.03% and the content of Ag is 0.09%.

[0119] The specific surface area of the catalyst obtained by BET method is 7m 2 / g.

[0120] Example 3

[0121] This example provides a selective hydrogenation catalyst, wherein:

[0122] Carrier: Use a commercially available spherical alumina-magnesia carrier, wherein the mass content of magnesia is 10%, and the carrier diameter is 4 mm. After calcination at 1150 °C for 4 h, the water absorption rate is 0.50 and the specific surface area is 10.08m 2 / g. Weigh 100 g of the calcined carrier.

[0123] Catalyst preparation:

[0124] (1) Dissolve 0.315 g of silver nitrate in 50 ml of deionized water to obtain an aqueous solution containing silver salt. Immerse 100 g of the calcined carrier in the aqueous solution containing silver salt. After the solution is completely absorbed, let it stand for 6 hours, dry at 120 °C, and calcine at 550 °C for 4 hours to obtain semi-finished catalyst I;

[0125] (2) Take 57.85 g of lactic acid and mix it with semi-finished catalyst I, react at a constant temperature of 120 °C for 10 hours to obtain semi-finished catalyst II; The pore volume of the polylactic acid occupies 95.0% of the carrier pore volume;

[0126] (3) Weigh 20 mg of tris(4-formylphenyl)amine and mix it with 0.008 mg of dichloroacetic acid, dissolve them in 55 ml of dichloroethane, then mix with semi-finished catalyst II, stir and dropwise add a mixed solution of 29.24 mg of 2-chloro-4,4”-diaminoterphenyl and 10 ml of trichloroethane. After the addition is complete, let the mixture stand at room temperature for 150 hours, pour out the residual liquid, wash the obtained product with ethanol and deionized water respectively, and then dry to obtain semi-finished catalyst III;

[0127] (4) Dissolve 84.39 mg of palladium acetate in 50 ml of chloroform. Wait until the palladium acetate is completely dissolved to obtain a palladium acetate solution; Immerse semi-finished catalyst III in 50 ml of ethanol to obtain an ethanol solution containing semi-finished catalyst III; Under stirring conditions, dropwise add the palladium acetate solution to the ethanol solution containing semi-finished catalyst III. After the addition is complete, let it stand for 4 hours, pour out the residual liquid, wash the obtained product with deionized water, then dry at 120 °C and calcine at 400 °C for 4 hours to obtain a catalyst semi-finished product;

[0128] (5) Weigh 14.76 g of copper nitrate and dissolve it in 50 g of deionized water. Immerse the catalyst semi-finished product in the copper nitrate solution. After the solution has completely absorbed, let it stand for 4 hours, pour out the solution, wash the obtained product with deionized water, dry at 120 °C, and then calcine at 360 °C for 6 hours to obtain the described selective hydrogenation catalyst.

[0129] After testing, the selective hydrogenation catalyst of this example includes a carrier, a first promoter Ag supported on the carrier, an organic cage supported on the carrier, an active component Pd supported in the organic cage, and a second promoter Cu supported on the carrier.

[0130] In the catalyst obtained by atomic absorption spectrometry, based on the mass of the carrier being 100%, the content of Pd is 0.04%, the content of Ag is 0.2%, and the content of Cu is 5%.

[0131] The maximum pore diameter of the organic cage in this example measured by the BET method is 3.45 nm, and the minimum pore diameter is 2.70 nm.

[0132] The specific surface area of the catalyst obtained by the BET method is 10.08 m 2 / g.

[0133] Comparative Example 3

[0134] This comparative example provides a selective hydrogenation catalyst, wherein:

[0135] Carrier: The same carrier as in Example 3 is used.

[0136] Catalyst preparation: The preparation conditions are basically the same as those in Example 3, except that the amount of tris(4-formylphenyl)amine in this comparative example is 5 times that in Example 3, and the amounts of dichloroacetic acid and 2-chloro-4,4”-diaminoterphenyl are also higher than those in Example 3.

[0137] (1) Dissolve 0.315 g of silver nitrate in 50 ml of deionized water to obtain an aqueous solution containing silver salt. Immerse 100 g of the calcined support in this aqueous solution containing silver salt. After the solution is completely absorbed, let it stand for 6 hours, dry at 120 °C, and calcine at 550 °C for 4 hours to obtain semi-finished catalyst A3.

[0138] (2) Take 57.85 g of lactic acid and mix it with semi-finished catalyst A3, and react at a constant temperature of 120 °C for 10 hours to obtain semi-finished catalyst B3; The polylactic acid occupies 95.0% of the pore volume of the support.

[0139] (3) Weigh 100 mg of tris(4-formylphenyl)amine and 33.33 mg of dichloroacetic acid, dissolve them in 55 ml of dichloroethane, then mix with semi-finished catalyst B3, stir and dropwise add a mixed solution of 131.84 mg of 2-chloro-4,4”-diaminoterphenyl and 10 ml of trichloroethane. After the dropping is completed, let the mixture stand at room temperature for 150 hours, pour out the residual liquid, wash the obtained product with ethanol and deionized water respectively, and then dry to obtain semi-finished catalyst C3.

[0140] (4) Dissolve 84.39 mg of palladium acetate in 50 ml of chloroform. Wait until the palladium acetate is completely dissolved to obtain a palladium acetate solution; Immerse semi-finished catalyst C3 in 50 ml of ethanol to obtain an ethanol solution containing semi-finished catalyst C3; Under stirring conditions, drop the palladium acetate solution into the ethanol solution containing semi-finished catalyst C3. After the dropping is completed, let it stand for 4 hours, pour out the residual liquid, wash the obtained product with deionized water, then dry at 120 °C, and then calcine at 400 °C for 4 hours to obtain a semi-finished catalyst.

[0141] (5) Weigh 14.76 g of copper nitrate and dissolve it in 50 g of deionized water. Immerse the semi-finished catalyst in the copper nitrate solution. After the solution is completely absorbed, let it stand for 4 hours, pour out the solution, wash the obtained product with deionized water, dry at 120 °C, and then calcine at 360 °C for 6 hours to obtain the selective hydrogenation catalyst.

[0142] In the catalyst obtained by atomic absorption spectrometry, based on the mass of the support being 100%, the content of Pd is 0.04%, the content of Ag is 0.2%, and the content of Cu is 5%.

[0143] The specific surface area of the catalyst obtained by BET method is 10.08 m 2 / g.

[0144] Example 4

[0145] This example provides a selective hydrogenation catalyst, where:

[0146] Support: A commercially available tooth-shaped spherical alumina support with a diameter of 4.5 mm is used. After calcination at 1175 °C for 4 h, the water absorption rate is 0.52 and the specific surface area is 8.2 m 2 / g. Weigh 100 g of the calcined support.

[0147] Catalyst preparation:

[0148] (1) Dissolve 0.236 g of silver nitrate in 52 ml of deionized water to obtain an aqueous solution containing silver salt. Immerse 100 g of the calcined support in the aqueous solution containing silver salt. After the solution is completely absorbed, let it stand for 8 hours, dry at 120 °C, and calcine at 550 °C for 4 hours to obtain semi-finished catalyst I;

[0149] (2) Take 49.14 g of lactic acid and mix it with semi-finished catalyst I. Heat it to 130 °C under stirring conditions and carry out a constant-temperature reaction for 2 hours to obtain semi-finished catalyst II; The polylactic acid occupies 75.0% of the pore volume of the support;

[0150] (3) Weigh 7 mg of tris(4-formylphenyl)amine and mix it with 0.00235 mg of trichloroacetic acid, dissolve them in 55 ml of dichloroethane, then mix with semi-finished catalyst II, stir and dropwise add a mixed solution of 11.62 mg of 2-ethyl-4,4”-diaminoterphenyl and 10 ml of trichloroethane. After the dropping is completed, let the mixture stand at room temperature for 150 hours, pour out the residual liquid, wash the obtained product with ethanol and deionized water respectively, and then dry to obtain semi-finished catalyst III;

[0151] (4) Dissolve 100 mg of palladium acetylacetonate in 50 ml of chloroform. Wait for the palladium acetylacetonate to completely dissolve to obtain a palladium acetylacetonate solution; Immerse semi-finished catalyst III in 50 ml of ethanol to obtain an ethanol solution containing semi-finished catalyst III; Under stirring conditions, dropwise add the palladium acetylacetonate solution to the ethanol solution containing semi-finished catalyst III. After the dropping is completed, let it stand for 4 hours, pour out the residual liquid, wash the obtained product with deionized water, then dry at 120 °C and calcine at 380 °C for 2 hours to obtain a catalyst semi-finished product;

[0152] (5) Dissolve 2.95 g of copper nitrate in 52 g of deionized water. Immerse the catalyst semi-finished product in the copper nitrate solution. After the solution is completely absorbed, let it stand for 4 hours, then dropwise add 5 ml of a 10% hydrazine hydrate solution by mass, stir at room temperature for 1 hour, pour out the solution, wash the obtained product with deionized water, and dry at 120 °C to obtain the described selective hydrogenation catalyst.

[0153] After detection, the selective hydrogenation catalyst of this example includes a carrier, a first promoter Ag supported on the carrier, an organic cage supported on the carrier, an active component Pd supported in the organic cage, and a second promoter Cu supported on the carrier.

[0154] In the catalyst obtained by atomic absorption spectrometry, based on the mass of the carrier being 100%, the content of Pd is 0.035%, the content of Ag is 0.15%, and the content of Cu is 1%.

[0155] The maximum pore diameter of the organic cage in this example measured by the BET method is 3.41 nm, and the minimum pore diameter is 2.86 nm.

[0156] The specific surface area of the catalyst obtained by the BET method is 8.2 m 2 / g.

[0157] Comparative Example 4

[0158] This comparative example provides a selective hydrogenation catalyst, wherein:

[0159] Carrier: The same carrier as in Example 4 is used.

[0160] Catalyst preparation: The preparation conditions are basically the same as in Example 4, except that the calcination temperature in step (4) is 180 °C.

[0161] (1) Dissolve 0.236 g of silver nitrate in 52 ml of deionized water to obtain an aqueous solution containing silver salt. Immerse 100 g of the calcined carrier in the aqueous solution containing silver salt. After the solution is completely absorbed, let it stand for 8 hours, dry at 120 °C, and calcine at 550 °C for 4 hours to obtain semi-finished catalyst A4;

[0162] (2) Take 49.14 g of lactic acid and mix it with semi-finished catalyst A4. Heat it to 130 °C under stirring conditions and react at a constant temperature for 2 hours to obtain semi-finished catalyst B4; The polylactic acid occupies 75.0% of the pore volume of the carrier;

[0163] (3) Weigh 7 mg of tris(4-formylphenyl)amine and mix it with 0.00235 mg of trichloroacetic acid. Dissolve them in 55 ml of dichloroethane, then mix with semi-finished catalyst B4, stir and dropwise add a mixed solution of 11.62 mg of 2-ethyl-4,4”-diaminotetraphenyl and 10 ml of trichloroethane. After the dropping is completed, let the mixture stand at room temperature for 150 hours, pour out the residual liquid, wash the obtained product with ethanol and deionized water respectively, and then dry to obtain semi-finished catalyst C4;

[0164] (4) Dissolve 100 mg 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 C4 in 50 ml of ethanol to obtain an ethanol solution containing the semi-finished catalyst C4; Under stirring conditions, drop the palladium acetylacetonate solution into the ethanol solution containing the semi-finished catalyst C4. After the dropping is completed, let it stand for 4 hours, pour off the residual liquid, wash the obtained product with deionized water, then dry it at 120 °C and calcine it at 180 °C for 2 hours to obtain a semi-finished catalyst;

[0165] (5) Weigh 2.95 g of copper nitrate and dissolve it in 52 g of deionized water. Immerse the semi-finished catalyst in the copper nitrate solution. After the solution is completely absorbed, let it stand for 4 hours, then drop 5 ml of a hydrazine hydrate solution with a mass concentration of 10%. Stir at room temperature for 1 hour, pour off the solution, wash the obtained product with deionized water, and dry it at 120 °C to obtain the selective hydrogenation catalyst.

[0166] In the catalyst obtained by atomic absorption spectrometry, based on the mass of the carrier being 100%, the content of Pd is 0.035%, the content of Ag is 0.15%, and the content of Cu is 1%.

[0167] The specific surface area of the catalyst obtained by the BET method is 8.2 m 2 / g.

[0168] Example 5

[0169] This example provides a selective hydrogenation catalyst, wherein:

[0170] Carrier: Use a spherical alumina-magnesia carrier, where the mass content of magnesia is 10% and the carrier diameter is 3 mm. After calcination at 1205 °C for 4 h, the water absorption rate is 0.41 and the specific surface area is 5.2 m 2 / g. Weigh 100 g of the calcined carrier.

[0171] Catalyst preparation:

[0172] (1) Dissolve 0.159 g of silver nitrate in 41 ml of deionized water to obtain an aqueous solution containing a silver salt. Immerse 100 g of the calcined carrier in the aqueous solution containing the silver salt. After the solution is completely absorbed, let it stand for 2 hours, dry at 120 °C, and calcine at 550 °C for 4 hours to obtain a semi-finished catalyst I;

[0173] (2) Take 36.25 g of an aqueous acrylic acid solution containing 20% (mass fraction) of water, 0.015 g of potassium hypophosphite monohydrate, 0.02 g of copper acetate monohydrate, and 0.15 ml of 35% (mass fraction) hydrogen peroxide as initiators. After mixing evenly, a mixed solution containing acrylic acid is obtained. Immerse the semi-finished catalyst I in this mixed solution. After all the solution is absorbed, transfer it to a reflux flask and heat it to 85 °C under stirring conditions. React at a constant temperature for 1 hour to obtain the semi-finished catalyst II. Polyacrylic acid occupies 83.41% of the pore volume of the carrier;

[0174] (3) Weigh 3.13 mg of tris(4-formylphenyl)amine and mix it with 0.00313 mg of trichloroacetic acid. Dissolve them in 50 ml of dichloroethane, then mix with the semi-finished catalyst II. Stir and dropwise add a mixed solution of 5.70 mg of 2-fluoro-4,4”-diaminoterphenyl and 10 ml of trichloroethane. After the addition is complete, let the mixture stand at room temperature for 150 hours. Decant the residual liquid, wash the obtained product with ethanol and deionized water respectively, and then dry it to obtain the semi-finished catalyst III;

[0175] (4) Dissolve 71.57 mg of palladium acetylacetonate in 50 ml of chloroform. Wait until the palladium acetylacetonate is completely dissolved to obtain a palladium acetylacetonate solution. Immerse the semi-finished catalyst III in 50 ml of ethanol to obtain an ethanol solution containing the semi-finished catalyst III. Under stirring conditions, dropwise add the palladium acetylacetonate solution to the ethanol solution containing the semi-finished catalyst III. After the addition is complete, let it stand for 4 hours. Decant the residual liquid, wash the obtained product with deionized water, then dry it at 120 °C and calcine it at 400 °C for 2 hours to obtain the catalyst semi-finished product;

[0176] (5) Weigh 8.85 g of copper nitrate and dissolve it in 41 g of deionized water. Immerse the catalyst semi-finished product in the copper nitrate solution. After all the solution is absorbed, let it stand for 4 hours. Decant the solution, wash the obtained product with deionized water, dry it at 120 °C, and then calcine it at 400 °C for 5 hours to obtain the described selective hydrogenation catalyst.

[0177] After testing, the selective hydrogenation catalyst of this example includes a carrier, a first promoter Ag supported on the carrier, an organic cage supported on the carrier, an active component Pd supported in the organic cage, and a second promoter Cu supported on the carrier.

[0178] In the catalyst obtained by atomic absorption spectrometry, based on the mass of the carrier being 100%, the content of Pd is 0.025%, the content of Ag is 0.10%, and the content of Cu is 3%.

[0179] The BET method measures that the maximum pore diameter of the organic cage in this example is 3.55 nm and the minimum pore diameter is 2.95 nm.

[0180] The specific surface area of the catalyst obtained by the BET method is 5.2 m 2 / g.

[0181] Comparative Example 5

[0182] This comparative example provides a selective hydrogenation catalyst, wherein:

[0183] Support: The same support as in Example 5 is used.

[0184] Catalyst preparation: The preparation conditions are basically the same as those in Example 5, except that 3-methyl-4,4”-terphenyl diamine with the same molar amount as 2-fluoro-4,4”-diaminoterphenyl is used to prepare the organic cage together with raw materials such as tris(4-formylphenyl)amine.

[0185] (1) Dissolve 0.159 g of silver nitrate in 41 ml of deionized water to obtain an aqueous solution containing silver salt. Immerse 100 g of the calcined support in this aqueous solution containing silver salt. After the solution is completely absorbed, let it stand for 2 hours, dry at 120 °C, and calcine at 550 °C for 4 hours to obtain semi-finished catalyst A5;

[0186] (2) Take 36.25 g of an aqueous acrylic acid solution containing 20% (mass fraction) of water, 0.015 g of potassium hypophosphite monohydrate, 0.02 g of copper acetate monohydrate, and 0.15 ml of 35% (mass fraction) hydrogen peroxide as an initiator. After mixing evenly, obtain a mixed solution containing acrylic acid; Immerse semi-finished catalyst A5 in this mixed solution. After the solution is completely absorbed, transfer it to a reflux flask and heat it to 85 °C under stirring conditions and react at a constant temperature for 1 hour to obtain semi-finished catalyst B5; Polyacrylic acid occupies 83.41% of the pore volume of the support;

[0187] (3) Weigh 3.13 mg of tris(4-formylphenyl)amine and 0.00313 mg of trichloroacetic acid, dissolve them in 50 ml of dichloroethane, then mix with semi-finished catalyst B5, stir and dropwise add a mixed solution of 4.38 mg of 3-methyl-4,4”-terphenyl diamine and 10 ml of trichloroethane. After the dropping is completed, let the mixture stand at room temperature for 150 hours, pour out the residual liquid, wash the obtained product with ethanol and deionized water respectively, and then dry to obtain semi-finished catalyst C5;

[0188] (4) Dissolve 71.57 mg 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 C5 in 50 ml of ethanol to obtain an ethanol solution containing the semi-finished catalyst C5; under stirring conditions, drop the palladium acetylacetonate solution into the ethanol solution containing the semi-finished catalyst C5. After the dropping is completed, let it stand for 4 hours, pour off the residual liquid, wash the obtained product with deionized water, then dry it at 120 °C and calcine it at 400 °C for 2 hours to obtain a semi-finished catalyst;

[0189] (5) Weigh 8.85 g of copper nitrate and dissolve it in 41 g of deionized water. Immerse the semi-finished catalyst in the copper nitrate solution. After the solution is completely absorbed, let it stand for 4 hours, pour off the solution, wash the obtained product with deionized water, dry it at 120 °C, and then calcine it at 400 °C for 5 hours to obtain the selective hydrogenation catalyst.

[0190] In the catalyst obtained by atomic absorption spectrometry, based on the mass of the carrier being 100%, the content of Pd is 0.025%, the content of Ag is 0.10%, and the content of Cu is 3%.

[0191] The specific surface area of the catalyst obtained by the BET method is 5.2 m 2 / g.

[0192] Example 6

[0193] This example provides a selective hydrogenation catalyst, wherein:

[0194] Carrier: Use a commercially available spherical alumina carrier with a diameter of 2 mm. After calcination at 1130 °C for 4 h, the water absorption rate is 0.60 and the specific surface area is 14.92 m 2 / g. Weigh 100 g of the calcined carrier.

[0195] Catalyst preparation:

[0196] (1) Dissolve 0.189 g of silver nitrate in 60 ml of deionized water to obtain an aqueous solution containing silver salt. Immerse 100 g of the calcined carrier in the aqueous solution containing silver salt. After the solution is completely absorbed, let it stand for 10 hours, dry it at 120 °C, and calcine it at 500 °C for 4 hours to obtain a semi-finished catalyst I;

[0197] (2) Take 60.48 g of lactic acid and mix it with the semi-finished catalyst I, and react at a constant temperature of 125 °C for 3 hours to obtain a semi-finished catalyst II; The polylactic acid occupies 80.0% of the pore volume of the carrier;

[0198] (3) Weigh 10.54 mg of tris(4-formylphenyl)amine and mix it with 0.0087 mg of difluoroacetic acid, dissolve them in 70 ml of dichloroethane, then mix with semi-finished catalyst II, stir and dropwise add a mixed solution of 14.756 mg of 4,4”-diaminoterphenyl and 10 ml of dichloroethane. After the addition is completed, let the mixture stand at room temperature for 120 hours, pour out the residual liquid, wash the obtained product with ethanol and deionized water respectively, and then dry it to obtain semi-finished catalyst III;

[0199] (4) Dissolve 63.29 mg of palladium acetate in 60 ml of glacial acetic acid. Wait until the palladium acetate is completely dissolved to obtain a palladium acetate solution; Immerse semi-finished catalyst III in 70 ml of ethanol to obtain an ethanol solution containing semi-finished catalyst III; Under stirring conditions, dropwise add the palladium acetate solution to the ethanol solution containing semi-finished catalyst III. After the addition is completed, let it stand for 4 hours, then dropwise add 3 ml of a 5% hydrazine hydrate solution. After the addition is completed, stir at room temperature for 1 hour, pour out the residual liquid, wash the obtained product with deionized water, then dry it at 120 °C, and then calcine it at 320 °C for 2 hours to obtain a semi-finished catalyst;

[0200] (5) Weigh 11.81 g of copper nitrate and dissolve it in 60 ml of deionized water. Immerse the semi-finished catalyst in the copper nitrate solution. After the solution has completely absorbed it, let it stand for 4 hours, then dropwise add 3 ml of a 5% hydrazine hydrate solution, stir at room temperature for 1 hour, pour out the solution, wash the obtained product with deionized water, and after drying at 120 °C, obtain the described selective hydrogenation catalyst.

[0201] After testing, the selective hydrogenation catalyst of this example includes a support, the first promoter Ag supported on the support, an organic cage supported on the support, the active component Pd supported in the organic cage, and the second promoter Cu supported on the support.

[0202] In the catalyst obtained by atomic absorption spectrometry, based on the mass of the support being 100%, the content of Pd is 0.03%, the content of Ag is 0.12%, and the content of Cu is 4%.

[0203] The maximum pore diameter of the organic cage in this example measured by the BET method is 3.38 nm, and the minimum pore diameter is 2.76 nm.

[0204] The specific surface area of the catalyst obtained by the BET method is 14.92 m 2 / g.

[0205] Comparative Example 6

[0206] This comparative example provides a selective hydrogenation catalyst, wherein:

[0207] Support: The same support as in Example 6 is used.

[0208] Catalyst preparation: The preparation conditions are basically the same as those in Example 6, except that the palladium salt in the palladium precursor solution in step (4) is palladium chloride.

[0209] (1) Dissolve 0.189 g of silver nitrate in 60 ml of deionized water to obtain an aqueous solution containing silver salt. Immerse 100 g of the calcined support in the aqueous solution containing silver salt. After the solution is completely absorbed, let it stand for 10 hours, dry at 120 °C, and calcine at 500 °C for 4 hours to obtain semi-finished catalyst A6.

[0210] (2) Take 60.48 g of lactic acid and mix it with semi-finished catalyst A6, and react at a constant temperature of 125 °C for 3 hours to obtain semi-finished catalyst B6; The polylactic acid occupies 80.0% of the pore volume of the support.

[0211] (3) Weigh 10.54 mg of tris(4-formylphenyl)amine and mix it with 0.0087 mg of difluoroacetic acid, dissolve them in 70 ml of dichloroethane, then mix with semi-finished catalyst B6, stir and add dropwise a mixed solution of 14.756 mg of 4,4”-diaminoterphenyl and 10 ml of dichloroethane. After the addition is completed, let the mixture stand at room temperature for 120 hours, pour out the residual liquid, wash the obtained product with ethanol and deionized water respectively, and then dry to obtain semi-finished catalyst C6.

[0212] (4) Dissolve 50 mg of palladium chloride in 60 ml of water. After the palladium chloride is completely dissolved, obtain a palladium chloride solution; Immerse semi-finished catalyst C6 in 70 ml of ethanol to obtain an ethanol solution containing semi-finished catalyst C6; Under stirring conditions, dropwise add the palladium chloride solution to the ethanol solution containing semi-finished catalyst C6. After the addition is completed, let it stand for 4 hours, then add dropwise 3 ml of a 5% hydrazine hydrate solution. After the addition is completed, stir at room temperature for 1 hour, pour out the residual liquid, wash the obtained product with deionized water, then dry at 120 °C, and then calcine at 320 °C for 2 hours to obtain a semi-finished catalyst.

[0213] (5) Weigh 11.81 g of copper nitrate and dissolve it in 60 ml of deionized water. Immerse the semi-finished catalyst in the copper nitrate solution. After the solution is completely absorbed, let it stand for 4 hours, then add dropwise 3 ml of a 5% hydrazine hydrate solution, stir at room temperature for 1 hour, pour out the solution, wash the obtained product with deionized water, dry at 120 °C, and obtain the selective hydrogenation catalyst.

[0214] In the obtained catalyst determined by atomic absorption spectrometry, based on the mass of the support being 100%, the content of Pd is 0.03%, the content of Ag is 0.12%, and the content of Cu is 4%.

[0215] The specific surface area of the catalyst obtained by the BET method is 14.92 m 2 / g.

[0216] Example 7

[0217] This example provides a selective hydrogenation catalyst, where:

[0218] Support: Commercially available spherical alumina with a diameter of 3 mm is used. After calcination at 1130 °C for 4 h, the water absorption rate is 0.55 and the specific surface area is 13.56 m 2 / g. 100 g of the calcined support is weighed.

[0219] Catalyst preparation:

[0220] (1) 0.25 g of silver nitrate is dissolved in 55 ml of deionized water to obtain an aqueous solution containing silver salt. 100 g of the calcined support is impregnated in the aqueous solution containing silver salt. After the solution is completely absorbed, it is left standing for 2 hours, dried at 120 °C, and calcined at 500 °C for 4 hours to obtain semi-finished catalyst I;

[0221] (2) 65.84 g of lactic acid is mixed with semi-finished catalyst I and reacted at a constant temperature of 130 °C for 2 hours to obtain semi-finished catalyst II; The polylactic acid occupies 95.0% of the pore volume of the support;

[0222] (3) 6.25 mg of tris(4-formylphenyl)amine and 0.0048 mg of difluoroacetic acid are mixed and dissolved in 60 ml of dichloroethane, and then mixed with semi-finished catalyst II. 10.14 mg of 4,4”-diaminoterphenyl and 10 ml of dichloroethane are stirred and added dropwise. After the addition is complete, the mixture is left standing at room temperature for 120 hours. The residual liquid is poured out, and the obtained product is washed with ethanol and deionized water respectively, and then dried to obtain semi-finished catalyst III;

[0223] (4) 52.74 mg of palladium acetate is dissolved in 50 ml of chloroform. After the palladium acetate is completely dissolved, a palladium acetate solution is obtained; Semi-finished catalyst III is immersed in 50 ml of ethanol to obtain an ethanol solution containing semi-finished catalyst III; Under stirring conditions, the palladium acetate solution is added dropwise to the ethanol solution containing semi-finished catalyst III. After the addition is complete, it is left standing for 4 hours. The residual liquid is poured out, and the obtained product is washed with deionized water, then dried at 120 °C, and further calcined at 350 °C for 2 hours to obtain a catalyst semi-finished product;

[0224] (5) Weigh 14.75 g of copper nitrate and dissolve it in 55 ml of deionized water. Immerse the semi-finished catalyst into the copper nitrate solution. After the solution is completely absorbed, let it stand for 4 hours. Then, add dropwise 10 ml of formic acid aqueous solution with a mass concentration of 50%. Stir at 60 °C for 10 minutes. Decant the solution. Wash the obtained product with deionized water and dry it at 120 °C to obtain the selective hydrogenation catalyst described above.

[0225] After testing, the selective hydrogenation catalyst of this example includes a carrier, a first auxiliary agent Ag supported on the carrier, an organic cage supported on the carrier, an active component Pd supported in the organic cage, and a second auxiliary agent Cu supported on the carrier.

[0226] In the catalyst obtained by atomic absorption spectrometry, based on the mass of the carrier being 100%, the content of Pd is 0.025%, the content of Ag is 0.16%, and the content of Cu is 5%.

[0227] The maximum pore diameter of the organic cage in this example measured by the BET method is 3.47 nm, and the minimum pore diameter is 2.82 nm.

[0228] The specific surface area of the catalyst obtained by the BET method is 13.56 m 2 / g.

[0229] Comparative Example 7

[0230] This comparative example provides a selective hydrogenation catalyst, where:

[0231] Carrier: The same carrier as in Example 7 is used.

[0232] Catalyst preparation: The preparation conditions are basically the same as those in Example 7, with the difference that the calcination temperature in step (4) is 600 °C.

[0233] (1) Dissolve 0.25 g of silver nitrate in 55 ml of deionized water to obtain an aqueous solution containing silver salt. Immerse 100 g of the calcined carrier in this aqueous solution containing silver salt. After the solution is completely absorbed, let it stand for 2 hours, dry at 120 °C, and calcine at 500 °C for 4 hours to obtain semi-finished catalyst A7;

[0234] (2) Take 65.84 g of lactic acid and mix it with semi-finished catalyst A7, and react at a constant temperature of 130 °C for 2 hours to obtain semi-finished catalyst B7; The polylactic acid occupies 95.0% of the pore volume of the carrier;

[0235] (3) Weigh 6.25 mg of tris(4-formylphenyl)amine and mix it with 0.0048 mg of difluoroacetic acid, dissolve them in 60 ml of dichloroethane, then mix with semi-finished catalyst B7, stir and dropwise add a mixed solution of 10.14 mg of 4,4”-diaminoterphenyl and 10 ml of dichloroethane. After the addition is complete, let the mixture stand at room temperature for 120 hours, pour out the residual liquid, wash the obtained product with ethanol and deionized water respectively, and then dry to obtain semi-finished catalyst C7;

[0236] (4) Dissolve 52.74 mg of palladium acetate in 50 ml of chloroform. Wait until the palladium acetate is completely dissolved to obtain a palladium acetate solution; Immerse semi-finished catalyst C7 in 50 ml of ethanol to obtain an ethanol solution containing semi-finished catalyst C7; Under stirring conditions, dropwise add the palladium acetate solution to the ethanol solution containing semi-finished catalyst C7. After the addition is complete, let it stand for 4 hours, pour out the residual liquid, wash the obtained product with deionized water, then dry at 120 °C and calcine at 600 °C for 2 hours to obtain a semi-finished catalyst;

[0237] (5) Weigh 14.75 g of copper nitrate and dissolve it in 55 ml of deionized water. Immerse the semi-finished catalyst in the copper nitrate solution. After the solution has completely absorbed, let it stand for 4 hours, then dropwise add 10 ml of formic acid aqueous solution with a mass concentration of 50%. Stir at 60 °C for 10 minutes, pour out the solution, wash the obtained product with deionized water, and dry at 120 °C to obtain the said selective hydrogenation catalyst.

[0238] In the obtained catalyst determined by atomic absorption spectrometry, based on the mass of the carrier being 100%, the content of Pd is 0.025%, the content of Ag is 0.16%, and the content of Cu is 5%.

[0239] The specific surface area of the obtained catalyst determined by the BET method is 13.56 m 2 / g.

[0240] Example 8

[0241] This example provides a selective hydrogenation catalyst, where:

[0242] Carrier: Use commercially available spherical alumina with a diameter of 4.5 mm. After calcination at 1160 °C for 4 h, the water absorption rate is 0.50 and the specific surface area is 9.1 m 2 / g. Weigh 100 g of the calcined carrier.

[0243] Catalyst preparation:

[0244] (1) Dissolve 0.28 g of silver nitrate in 50 ml of deionized water to obtain an aqueous solution containing silver salt. Immerse 100 g of the calcined carrier in the aqueous solution containing silver salt. After all the solution is absorbed, let it stand for 2 hours, dry at 120 °C, and calcine at 520 °C for 4 hours to obtain semi-finished catalyst I;

[0245] (2) Take 47.25 g of lactic acid and mix it with semi-finished catalyst I, and react at a constant temperature of 130 °C for 2 hours to obtain semi-finished catalyst II; The polylactic acid occupies 75% of the pore volume of the carrier;

[0246] (3) Weigh 5.82 mg of tris(4-formylphenyl)amine and mix it with 0.0039 mg of difluoroacetic acid, dissolve them in 60 ml of dichloroethane, then mix with semi-finished catalyst II, stir and dropwise add a mixed solution of 9.44 mg of 4,4”-diaminoterphenyl and 10 ml of dichloroethane. After the dropping is completed, let the mixture stand at room temperature for 100 hours, pour out the residual liquid, wash the obtained product with ethanol and deionized water respectively, and then dry to obtain semi-finished catalyst III;

[0247] (4) Dissolve 67.51 mg of palladium acetate in 55 ml of chloroform. Wait for the palladium acetate to completely dissolve to obtain a palladium acetate solution; Immerse semi-finished catalyst III in 50 ml of methanol to obtain an ethanol solution containing semi-finished catalyst III; Under stirring conditions, dropwise add the palladium acetate solution to the methanol solution containing semi-finished catalyst III. After the dropping is completed, let it stand for 4 hours, pour out the residual liquid, wash the obtained product with deionized water, then dry at 120 °C, and then calcine at 350 °C for 2 hours to obtain the catalyst semi-finished product;

[0248] (5) Weigh 9.44 g of copper nitrate and dissolve it in 50 ml of deionized water. Immerse the catalyst semi-finished product in the copper nitrate solution. After all the solution is absorbed, let it stand for 4 hours, then dropwise add 10 ml of a 40% aqueous formaldehyde solution, stir at 40 °C for 200 minutes, pour out the solution, wash the obtained product with deionized water, and dry at 120 °C to obtain the selective hydrogenation catalyst.

[0249] After testing, the selective hydrogenation catalyst of this example includes a carrier, a first auxiliary agent Ag supported on the carrier, an organic cage supported on the carrier, an active component Pd supported in the organic cage, and a second auxiliary agent Cu supported on the carrier.

[0250] In the catalyst obtained by atomic absorption spectrometry, based on the mass of the carrier being 100%, the content of Pd is 0.032%, the content of Ag is 0.18%, and the content of Cu is 3.2%.

[0251] The BET method measures that the maximum pore diameter of the organic cage in this example is 3.50 nm and the minimum pore diameter is 2.86 nm.

[0252] The specific surface area of the catalyst obtained by the BET method is 9.1 m 2 / g.

[0253] Comparative Example 8

[0254] This comparative example provides a selective hydrogenation catalyst, wherein:

[0255] Support: The same support as in Example 8 is used.

[0256] Catalyst preparation: The preparation conditions are basically the same as those in Example 8, except that the Cu content in this comparative example is 0.3% (calculated based on the mass of the support being 100%).

[0257] (1) Dissolve 0.28 g of silver nitrate in 50 ml of deionized water to obtain an aqueous solution containing silver salt. Immerse 100 g of the calcined support in the aqueous solution containing silver salt. After the solution is completely absorbed, let it stand for 2 hours, dry at 120 °C, and calcine at 520 °C for 4 hours to obtain semi-finished catalyst A8;

[0258] (2) Take 47.25 g of lactic acid and mix it with semi-finished catalyst A8, and react at a constant temperature of 130 °C for 2 hours to obtain semi-finished catalyst B8; The polylactic acid occupies 75% of the pore volume of the support;

[0259] (3) Weigh 5.82 mg of tris(4-formylphenyl)amine and mix it with 0.0039 mg of difluoroacetic acid, dissolve them in 60 ml of dichloroethane, then mix with semi-finished catalyst B8, stir and dropwise add a mixed solution of 9.44 mg of 4,4”-diaminoterphenyl and 10 ml of dichloroethane. After the addition is completed, let the mixture stand at room temperature for 100 hours, pour out the residual liquid, wash the obtained product with ethanol and deionized water respectively, and then dry to obtain semi-finished catalyst C8;

[0260] (4) Dissolve 67.51 mg of palladium acetate in 55 ml of chloroform. Wait until the palladium acetate is completely dissolved to obtain a palladium acetate solution; Immerse semi-finished catalyst C8 in 50 ml of methanol to obtain a methanol solution containing semi-finished catalyst C8; Under stirring conditions, dropwise add the palladium acetate solution to the methanol solution containing semi-finished catalyst C8. After the addition is completed, let it stand for 4 hours, pour out the residual liquid, wash the obtained product with deionized water, then dry at 120 °C, and then calcine at 350 °C for 2 hours to obtain a catalyst semi-finished product;

[0261] (5) Weigh 0.89 g of copper nitrate and dissolve it in 50 ml of deionized water. Immerse the semi-finished catalyst into the copper nitrate solution. After the solution is completely absorbed, let it stand for 4 hours. Then, add dropwise 10 ml of formaldehyde aqueous solution with a mass concentration of 40%. Stir at 40 °C for 200 minutes. Decant the solution. Wash the obtained product with deionized water and dry it at 120 °C to obtain the selective hydrogenation catalyst described above.

[0262] In the catalyst obtained determined by atomic absorption spectrometry, based on the mass of the carrier being 100%, the content of Pd is 0.032%, the content of Ag is 0.18%, and the content of Cu is 0.3%.

[0263] The specific surface area of the catalyst obtained determined by the BET method is 9.1 m 2 / g.

[0264] Performance of the catalyst in the pre-hydrogenation reaction of C2

[0265] Evaluation method:

[0266] The loading amount of the catalyst in the fixed-bed single-stage reactor is 200 mL (recorded weight), the packing is 50 mL, the space velocity of the reaction material is 12000 / h, the operating pressure is 3.6 MPa, the initial reactor inlet temperature is 70 °C, and after 1000 hours, the reactor inlet temperature is increased to 73 °C.

[0267] Catalyst reduction: The hydrogen flow rate is 10 L / h, and it is reduced at a constant temperature of 130 °C for 4 hours.

[0268] The calculation method of the catalyst evaluation results is shown in Table 1.

[0269] Table 1 Calculation method of evaluation results

[0270]

[0271] The initial selectivity is the selectivity measured 24 hours after the reactor is charged.

[0272] The initial activity is the activity (acetylene conversion rate) measured 24 hours after the reactor is charged.

[0273] The composition of the reaction material is as follows:

[0274] CH 4 21%; H 2 25%; C 2 H 6 7%; C 2 H 4 35%; C 2 H 2 0.6%; C 3 H 69.4%; C 3 H 8 1.44%; 0.2% propyne; 0.2% allene; C 4 0.1%; 0.06% CO.

[0275] The catalyst evaluation results of the above examples and comparative examples are shown in Table 2.

[0276] Table 2 Catalyst Evaluation Results

[0277]

[0278] It can be seen from the comparison of the catalyst evaluation results in Table 2 that:

[0279] In Example 1, after 1500 hours, the ethylene selectivity decreased by 5.5%. In Comparative Example 1, since silver was not loaded, the selectivity decreased by more than 10.49% after 1500 hours, which was nearly 5 percentage points lower than that in Example 1.

[0280] In Comparative Example 2, since the pore volume of the carrier occupied by the polar polymer was only 40% and the organic cages were distributed in 60% of the pores of the carrier, acetylene, CO, etc. could not diffuse to the surface of the catalyst in time during the reaction, and more ethylene underwent hydrogenation reaction, resulting in a significantly lower selectivity than that in Example 2.

[0281] The catalyst activity in Comparative Example 3 was very low. In general, for the pre-hydrogenation reaction, the requirement for a single reactor is that the acetylene conversion rate exceeds 45%. The catalyst prepared under this condition was unqualified. The reason may be that in Comparative Example 3, the amount of tris(4-formylphenyl)amine increased significantly, and correspondingly, the amount of 2-chloro-4,4”-diaminoterphenyl also increased. The number of synthesized organic cages increased, and the number of corresponding active centers was excessive. The size of the palladium active centers loaded on a single organic cage became smaller, resulting in insufficient catalyst activity. Especially when CO was present, its adsorption strength on the smaller-sized palladium active centers was greater, and the impact on the activity was greater.

[0282] The catalyst activity in Comparative Example 4 was also significantly low. The reason may be that the calcination temperature in step (4) of Comparative Example 4 was 180°C, and the polar polymer synthesized in the carrier did not decompose at this temperature, resulting in the copper loaded in step (5) being located on the surface of the catalyst, covering the palladium active centers.

[0283] The monomer used for synthesizing the organic cages in Comparative Example 5 was terphenyl diamine, and the synthesized organic cages had a smaller size. Correspondingly, the active center particles were smaller, and its activity was significantly insufficient under the condition of up to 600 ppm CO.

[0284] The catalyst activity in Comparative Example 6 is very low. The reason may be that the palladium precursor used in step (4) of Comparative Example 6 is not an organic palladium salt but an inorganic palladium salt. After this palladium salt is dissolved in water, it is loaded in the form of an anion complex and does not enter the organic cage. When calcined at 320 °C, it cannot effectively form active centers of a certain size and is covered by the subsequently loaded copper, so its activity is very low.

[0285] In Comparative Example 7, the calcination temperature in step (4) reaches 600 °C, causing the disintegration of the organic cage structure. Palladium agglomerates to form larger active centers, and the activity of its single active center is too high, and the hydrodimerization reaction is also very intense. Although the activity can meet the standard after 1500 hours, the selectivity decreases by more than 6.6%.

[0286] In Comparative Example 8, the copper loading is 0.3%. Due to the low loading, the formed active centers do not have the activity for hydrogenating carbonyl compounds, and the selectivity decreases significantly after 1500 hours.

[0287] Examples 1 and 2 are not loaded with copper, and their selectivities both exceed 5.5% after 1500 hours. For Examples 3-7, the copper loading is more than 1%. After the copper loading reaches 1%, the attenuation of the catalyst selectivity is all below 3%, indicating that the effective loading of copper is beneficial to improving the performance stability of the catalyst.

Claims

1. A selective hydrogenation catalyst, which comprises a support, a first promoter Ag supported on the support, an organic cage supported on the support, and an active component Pd supported in the organic cage; Wherein, Based on the mass of the support being 100%, the content of Pd is 0.02 - 0.04%, the content of Ag is 0.05 - 0.2%, and the size of the organic cage is 2.7 - 3.6 nm.

2. The selective hydrogenation catalyst according to claim 1, Wherein, The selective hydrogenation catalyst further comprises a second promoter Cu supported on the support. Based on the mass of the support being 100%, the content of Cu is 1 - 5%.

3. The selective hydrogenation catalyst according to claim 1, Wherein, The specific surface area of the selective hydrogenation catalyst is 1-15 m 2 / g.

4. A preparation method of a selective hydrogenation catalyst, which Comprises the following steps: (1) Load a first promoter Ag on the support to obtain a semi-finished catalyst I; (2) Synthesize a polar polymer on the semi-finished catalyst I obtained in step (1), and the polar polymer occupies 70 - 95% of the pore volume of the support to obtain a semi-finished catalyst II; (3) Synthesize an organic cage on the semi-finished catalyst II obtained in step (2) to obtain a semi-finished catalyst III; (4) Load a palladium active component in the organic cage of the semi-finished catalyst III obtained in step (3) to obtain the said selective hydrogenation catalyst.

5. The preparation method according to claim 4, Wherein, In step (1), the support comprises one or a combination of several of silica, zinc oxide, magnesium oxide, alumina and titanium oxide; Preferably, the carrier is a calcined carrier, and the specific surface area of the calcined carrier is 1-15 m 2 / g; Preferably, step (1) specifically comprises: impregnating the calcined support in an aqueous solution containing a silver salt, and after the solution is completely absorbed, standing for a period of time, and at least drying and calcining to obtain the said semi-finished catalyst I.

6. The preparation method according to claim 4, Wherein, In step (2), the polar polymer occupies 75 - 95% of the pore volume of the support; Preferably, in step (2), the polar polymer comprises polyacrylic acid and / or polylactic acid.

7. The preparation method according to claim 4, Wherein, Step (2) specifically comprises: mixing a hydrophilic polymer monomer with the semi-finished catalyst I and carrying out a polymerization reaction to obtain the semi-finished catalyst II, and the polar polymer occupies 70 - 95% of the pore volume of the support; Preferably, the hydrophilic polymer monomer comprises acrylic acid and / or lactic acid.

8. The preparation method according to claim 4, Wherein, Step (3) specifically comprises: mixing tris(4-formylphenyl)amine with a haloacetic acid in a haloalkane to obtain a mixed solution; then mixing the mixed solution with the semi-finished catalyst II, and dropwise adding a mixed solution of an aromatic diamine compound and a haloalkane under stirring conditions. After the dropwise addition is completed, stand for a period of time. After the reaction is complete, wash and dry the obtained product at least to obtain the semi-finished catalyst III; Preferably, in step (3), the mass ratio of tris(4-formylphenyl)amine to the haloacetic acid is 1000 - 3000:1; Preferably, in step (3), the molar ratio of the aromatic diamine compound to the tris(4-formylphenyl)amine is 1.3 - 2.0:

1.

9. The preparation method according to claim 8, wherein, in step (3), the haloacetic acid includes trifluoroacetic acid and / or dichloroacetic acid.

10. The preparation method according to claim 8, wherein, in step (3), the aromatic diamine compound includes a diamine compound containing a quaterphenyl; Preferably, the aromatic diamine compound includes one or a combination of several of 4,4”-diaminoterphenyl, halo-substituted 4,4”-diaminoterphenyl, and alkyl-substituted 4,4”-diaminoterphenyl.

11. The preparation method according to claim 8, wherein, in step (3), the standing time is 50 - 200 hours.

12. The preparation method according to claim 8, wherein, Step (4) specifically includes: immersing the semi-finished catalyst III in alcohol, dropping a palladium precursor solution into it under stirring conditions, after standing for a period of time, and then obtaining the selective hydrogenation catalyst after at least drying and calcination, and the palladium active component is loaded in the organic cage; Preferably, in step (4), the palladium precursor solution includes a solution of an organic palladium salt in an organic solvent; more preferably, the organic palladium salt includes palladium acetate and / or palladium acetylacetonate; Preferably, in step (4), the mass ratio of palladium in the palladium precursor solution to the tris(4-formylphenyl)amine is 1.5 - 10:1; Preferably, step (4) further includes: after the dropping of the palladium precursor solution is completed and standing for a period of time, adding a reducing agent.

13. The preparation method according to claim 12, wherein, in step (4), the calcination temperature is from the decomposition temperature of the polar polymer to below 450 °C; Preferably, the calcination temperature is from the decomposition temperature of the polar polymer to below 430 °C.

14. The preparation method according to claim 4, wherein, The preparation method further includes step (5) after step (4): loading a second promoter Cu onto the product obtained in step (4) to obtain the selective hydrogenation catalyst; Preferably, step (5) specifically includes: immersing the product obtained in step (4) in an aqueous solution containing a copper salt, after the solution is completely absorbed, standing for a period of time, and obtaining the selective hydrogenation catalyst after at least drying; Preferably, step (5) further includes: immersing the product obtained in step (4) in an aqueous solution containing a copper salt, after the solution is completely absorbed, standing for a period of time, then adding a reducing agent, stirring for a period of time, and then obtaining the selective hydrogenation catalyst after at least the drying.

15. A selective hydrogenation catalyst, which is prepared by the preparation method of the selective hydrogenation catalyst according to any one of claims 4 - 14.

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