A catalyst for selective hydrogenation of carbon-3 fraction acetylenes and a method for preparing the same

Abstract

The application discloses a carbon three fraction alkyne selective hydrogenation catalyst and a preparation method thereof. The carrier of the catalyst is alumina or mainly alumina, the specific surface area of the catalyst is 30-100 m 2 / g; the catalyst further contains Pd and Ag, the content of Pd is 0.2-0.4 wt% and the content of Ag is 0.6-3.0 wt% based on 100% of the mass of the carrier, Pd is loaded in an organic cage; the organic cage is located in the interior of the catalyst and the distance between the organic cage and the outer surface of the catalyst is less than or equal to 0.2 mm, and the size of the organic cage is 1.9-2.7 nm. The carbon three fraction alkyne selective hydrogenation catalyst has the characteristics of high activity, high selectivity, low green oil generation and the like.

Description

Technical Field

[0001] This invention relates to a catalyst for the selective hydrogenation of alkynes in C3 fractions, and more particularly to a method for selectively hydrogenating propyne (MA) and propadiene (PD) contained in C3 fractions to propylene using a Pd-Ag catalyst prepared by "organic cage" synthesis. Background Technology

[0002] Propylene is one of the most important basic raw materials in the petrochemical industry and a crucial monomer for the synthesis of various polymers. It is mostly produced by steam cracking of petroleum hydrocarbons (such as ethane, propane, butane, naphtha, and light diesel oil). The C3 fraction obtained through this method, which is mainly composed of propylene, contains 1.5–8.0% propyne (PD) + propadiene (MA). The presence of MAPD affects the quality of polymer products, and currently, the petrochemical industry generally removes it using selective hydrogenation.

[0003] Traditional C3 hydrogenation catalysts use Al2O3 as a support, Pd as the active component, and Ag as a co-active component, with a specific surface area of ​​15–200 m². 2 / g. The catalyst is prepared by impregnation. During the impregnation and drying processes, the surface tension and solvation effects of the impregnation solution are particularly significant, causing the precursor metal active component to deposit as aggregates on the support surface. Furthermore, the distribution of Pd and Ag is not ideal, making it difficult to control the catalyst activity. The selectivity of the catalyst mainly depends on the pore size and dispersion state of the active components. Because the dispersion of the active components is affected by the number of surface groups on the support and solvation during catalyst preparation, the dispersion of the active components is highly random, resulting in poor reproducibility and ultimately unsatisfactory catalytic reaction performance.

[0004] Chinese patent CN98810096 discloses a catalytic distillation method for removing MAPD from C3 fractions. This method combines catalytic hydrogenation and distillation separation processes into one. Because heat exchange is sufficient during this process, temperature runaway is less likely, and the small amount of oligomers generated are easily carried away, significantly reducing coking on the catalyst surface. However, this method places high demands on the packing of the catalytic distillation column, and the fluid distribution significantly affects the separation effect. This method also increases the operational complexity.

[0005] Chinese patent CN201110086151.X discloses a method for selective hydrogenation of C3 fractions. This method uses a catalyst with Pd as the main active component, alumina as the support, and silver as a co-catalyst. Specific polymeric compounds are adsorbed onto the support, forming a polymeric coating of a certain thickness on the support surface. The functionalized compounds react with the polymers, giving them functional groups capable of complexing with the active components. The active components undergo a complexation reaction on the functional groups on the support surface, ensuring the ordered and highly dispersed nature of the active components. However, this method relies on the chemical adsorption of specific polymeric compounds onto the support via the hydroxyl groups of alumina. The amount of polymeric compounds adsorbed by the support is limited by the number of hydroxyl groups in the alumina. Furthermore, the complexation between the functionalized polymers and Pd is weak, sometimes failing to achieve the required active component loading, leaving some active components in the impregnation solution, increasing catalyst costs. The method also suffers from a complex process flow in preparing C3 hydrogenation catalysts.

[0006] Chinese patent CN102218323A discloses a hydrogenation catalyst for unsaturated hydrocarbons. The active component is a mixture of 5-15% nickel oxide and 1-10% other metal oxides, which can be one or more of molybdenum oxide, cobalt oxide, and iron oxide. It also includes 1-10% additives. This invention is mainly used for hydrogenating ethylene, propylene, butene, etc., from coal-to-oil industrial tail gases into saturated hydrocarbons, exhibiting good deep hydrogenation capabilities. However, this technology is primarily used for the complete hydrogenation of ethylene, propylene, butene, etc., from various industrial tail gases rich in CO and hydrogen, and is not suitable for the selective hydrogenation of alkynes and dienes.

[0007] Chinese patent CN200810114744.0 discloses a selective hydrogenation catalyst for unsaturated hydrocarbons and its preparation method. This catalyst uses alumina as a support and palladium as the active component, and its resistance to impurities and coking is improved by adding rare earth and alkaline earth metals and fluorine. However, its selectivity is not ideal.

[0008] Chinese patent CN201310114077.7 discloses a hydrogenation catalyst in which the active components are Pd, Ag, and Ni. Pd and Ag are supported using an aqueous solution impregnation method, while Ni is supported using a W / O microemulsion impregnation method. Using this method, Pd / Ag and Ni are located in pores of different sizes, allowing the generated green oil to be saturated with hydrogen in the macropores, thus reducing catalyst coking. However, the reduction temperature of Ni often reaches around 500℃. At this temperature, reduced Pd atoms easily aggregate, causing a significant decrease in catalyst activity. A substantial increase in the amount of active components is needed to compensate for the activity loss, but this in turn leads to a decrease in selectivity.

[0009] Chinese patent CN200810119385.8 discloses a non-precious metal supported selective hydrogenation catalyst, its preparation method, and its application. The catalyst includes a support and a main active component and a co-active component supported on that support. The main active component is Ni, and the co-active component is selected from at least one of Mo, La, Ag, Bi, Cu, Nd, Cs, Ce, Zn, and Zr. Both the main active component and the co-active component exist in an amorphous form with an average particle size <10 nm. The support is a non-oxidizing porous material. The catalyst is prepared using a microemulsion method. However, the catalyst prepared by this method has a wide particle size distribution of its active components, resulting in unsatisfactory catalyst activity.

[0010] Chinese Patent 200910084539.9 discloses a palladium-silver supported hydrogenation catalyst. The support mainly contains Al2O3, and the active components, metals Pd and Ag, are dispersed on the support. The catalyst is characterized by a Pd content of 0.01–1% and an Ag content of 0.017–5%, with a total metal dispersion of 30–65% for Pd and Ag. The catalyst has a specific surface area of ​​2–300 m². 2 / g, pore volume is 0.2~1.25mL / g, bulk density is 0.3~1.3g / cm³ 3 However, the active components of the catalyst prepared by this method are uniformly dispersed, not in an eggshell-like distribution, and are not effective for the hydrogenation refining of low-carbon olefins.

[0011] Chinese patent CN202111602774.8 discloses a method for preparing palladium cluster catalysts. First, organic molecular cages RCC3 are synthesized using trimesin and (1R,2R)-cyclohexanediamine as raw materials. Next, AT-RCC3 organic molecular cages are synthesized by reacting RCC3 with acetone, and FT-RCC3 organic molecular cages are synthesized by reacting RCC3 with paraformaldehyde. Then, Pd clusters are supported on the cavity confinement of the RCC3, AT-RCC3, and FT-RCC3 molecular cages to obtain Pd@RCC3, Pd@AT-RCC3, and Pd@FT-RCC3 catalysts with tunable Pd cluster sizes. However, the catalysts prepared by this method are bulk catalysts. Although they exhibit good catalytic performance, their high cost limits their industrial applicability.

[0012] In existing C3 fraction selective hydrogenation catalysts, the selective hydrogenation of alkynes occurs at the Pd-based main active sites. During catalyst preparation, activation is a high-temperature calcination process, during which metal salts generally decompose into metal oxides, which then form clusters. However, the aggregation of active components during calcination is a random process, resulting in the formation of mostly normally distributed active sites with a scale of 1-3 nm. Small-scale active sites result in insufficient activity; large-scale sites are prone to forming green oil.

[0013] Experiments showed that as long as the amount of active component and loading conditions remained constant, changing the reaction temperature and hydrogen quantity resulted in a relatively constant amount of green oil produced relative to the amount of inlet alkynes, indicating that the distribution of active site size is indeed influenced by statistical laws. (In actual reactions, since the green oil undergoes hydrogenation, the measured results are based on C5+). Therefore, preparing active sites with a uniform size distribution and reducing the formation of byproducts is of great significance for further extending the catalyst's operating time under high selectivity. Summary of the Invention

[0014] The purpose of this invention is to provide a selective hydrogenation catalyst for C3-fraction alkynes and its preparation method. This catalyst exhibits high activity, high selectivity, and low green oil formation. The catalyst contains an organic cage size of 1.9–2.7 nm, with uniformly dispersed palladium active component and a narrow particle size distribution.

[0015] To achieve the above objectives, the present invention provides a selective hydrogenation catalyst for C3 alkynes, wherein the catalyst support is alumina or mainly alumina, and the specific surface area of ​​the catalyst is 30–100 m². 2 / g; the catalyst also contains at least Pd and Ag, with Pd content of 0.2-0.4 wt% and Ag content of 0.6-3.0 wt% based on the mass of the support of 100%, and Pd is supported in an organic cage; the organic cage is located inside the catalyst and is less than or equal to 0.2 mm away from the outer surface of the catalyst, and the size of the organic cage is 1.9-2.7 nm.

[0016] Preferably, the content of Ag is 0.6 to 2.0 wt%.

[0017] Preferably, the alumina is in the θ, α, or a mixture thereof crystal form.

[0018] Preferably, the alumina content in the carrier is above 80 wt%.

[0019] This invention also provides a method for preparing a selective hydrogenation catalyst for C3 alkynes, the method comprising the following steps:

[0020] (1) Mix the hydrophilic polymerizable monomer with the calcined support and then carry out the polymerization reaction to obtain the semi-finished catalyst A;

[0021] (2) Tris(4-formylphenyl)amine is mixed with haloacetic acid and dissolved in haloalkane. Then it is mixed with semi-finished catalyst A, stirred and a mixed solution of phenyl diamine substituted product and haloalkane is added to obtain a mixture. The mixture is allowed to stand until the reaction is complete, and the residual liquid is poured off. The mixture is washed with alcohol and deionized water respectively and dried to obtain semi-finished catalyst B.

[0022] (3) Dissolve the organopalladium compound in a haloalkane until the organopalladium compound is completely dissolved and set aside.

[0023] (4) Immerse the semi-finished catalyst B in an alcohol solution, then add the solution prepared in step (3) to the mixture of semi-finished catalyst B and alcohol, stir at the same time, then add a reducing agent, heat and stir, wait until the surface of semi-finished catalyst B no longer changes color, pour off the solution, wash with deionized water, dry, and calcine to obtain semi-finished catalyst C.

[0024] (5) Dissolve the soluble silver salt in deionized water or organic solvent, add the semi-finished catalyst C, and after the solution is completely absorbed, let it stand and dry. Then add the reducing agent, heat and stir to reduce the silver, pour off the solution, wash with deionized water, and dry to obtain the C3 fraction alkyne selective hydrogenation catalyst.

[0025] Preferably, in step (1), the mass ratio of the hydrophilic polymerizable monomer to the calcined carrier is 40-80%.

[0026] Preferably, in step (1), the polymer synthesized by the hydrophilic polymerizable monomer through a polymerization reaction occupies the pores of the carrier, and the volume of the polymer is 80-95% of the pore volume of the carrier.

[0027] Preferably, in step (2), the number of moles of the phenyl diamine substituted product is 1.2 to 2 times the number of moles of tris(4-formylphenyl)amine, and the mass ratio of tris(4-formylphenyl)amine to haloacetic acid is 2000 to 6000:1.

[0028] Preferably, in step (3), the mass ratio of palladium to tris(4-formylphenyl)amine in the organic palladium compound is 0.63 to 4.8:1, based on the mass of palladium.

[0029] Preferably, the carrier is at least one of spherical, cylindrical, clover-shaped, and four-leaf clover-shaped.

[0030] The present invention does not particularly limit the type of hydrophilic polymerizable monomer in step (1). The hydrophilic polymerizable monomer may contain carbonyl or carboxyl groups and may undergo polymerization or condensation reactions. The hydrophilic polymerizable monomer is, for example, but not limited to, at least one of lactic acid, acrylic acid, and methacrylic acid.

[0031] The present invention does not specifically limit the calcination temperature of the calcined carrier in step (1), for example, but not limited to 1030-1110℃.

[0032] The present invention does not specifically limit the temperature and time of the polymerization reaction in step (1). The temperature of the polymerization reaction refers to the temperature at which the hydrophilic polymerizable monomer undergoes thermal condensation reaction or bulk polymerization. This temperature varies depending on the hydrophilic polymerizable monomer.

[0033] Preferably, in step (2), the phenyl diamine substitute is biphenyl diamine or its substitute, and the substituent is preferably a halogen or an alkane.

[0034] Preferably, in step (2), the haloacetic acid is a catalyst for the reaction of tris(4-formylphenyl)amine with phenyldiamine substitutes, and can be fluoroacetic acid or chloroacetic acid, preferably trifluoroacetic acid or dichloroacetic acid.

[0035] Preferably, in step (2), the haloalkane is the solvent required for the reaction, which can be a fluoroalkane, a chloroalkane or a bromoalkane, and can be a halomethane or a haloethane, preferably dichloroethane or trichloromethane.

[0036] The present invention does not specifically limit the alcohol in step (2), and the alcohol may be, for example, but not limited to, at least one of methanol, ethanol, and propanol.

[0037] Preferably, in step (3), the organopalladium compound can be at least one of palladium acetate and palladium acetylacetonate.

[0038] The present invention does not specifically limit the haloalkane in step (3), wherein the haloalkane is, for example, but not limited to, at least one of chloroform and dichloroethane.

[0039] Preferably, in step (4), the alcohol is at least one of ethanol and methanol, preferably ethanol.

[0040] Preferably, in step (4) or step (5), the reducing agent is a reducing compound, such as at least one of methanol, formaldehyde, formic acid, ethanol, acetaldehyde, and hydrazine hydrate.

[0041] Preferably, in step (4), the molar amount of the reducing agent is 1-3 molar amounts of palladium; the calcination temperature is 280-480℃ and the time is 3-8h.

[0042] The present invention does not specifically limit the stirring temperature and time in step (4), wherein the stirring temperature is, for example, but not limited to, 20-80°C, and the stirring time is, for example, but not limited to, 1-2h.

[0043] Preferably, in step (5), the soluble silver salt refers to a silver salt that is soluble in water or an organic solvent, such as silver nitrate that is soluble in water and silver acetylacetonate that is soluble in an organic solvent, with silver nitrate that is soluble in water being the preferred choice.

[0044] Preferably, in step (5), the amount of soluble silver salt added is such that the Ag content in the catalyst is 0.6 to 3.0 wt%.

[0045] The present invention does not specifically limit the drying temperature in step (5), which is, for example, but not limited to, 100-180°C.

[0046] The present invention does not specifically limit the stirring temperature and time in step (5), wherein the stirring temperature is, for example, but not limited to, 20-60°C, and the stirring time is, for example, but not limited to, 1-4h.

[0047] Preferably, in step (5), after loading silver and waiting for the solution to be completely absorbed, reduction can be omitted. That is, after the solution is completely absorbed, the solution is allowed to stand and dry, skipping the steps of "adding reducing agent, heating and stirring to reduce silver, pouring off the solution, washing with deionized water, and drying". The solution is directly calcined at 500-550℃ to obtain a C3 fraction alkyne selective hydrogenation catalyst.

[0048] The selective hydrogenation catalyst for C3 alkynes of this invention enables in-situ synthesis of regularly structured organic cages on the outer surface of a support. The organic cages have a size of 1.9–2.7 nm, and the active component Pd is loaded within these cages. Due to the size limitation of the organic cages, the active centers are also uniform in size, thus meeting the activity requirements without excessively large active centers. To ensure that the organic cages are located on the outer surface of the support, the pores inside the support are pre-occupied with other media, allowing the synthesis of the organic cages to occur within the pores near the outer surface.

[0049] In the C3 fraction alkyne selective hydrogenation catalyst of this invention, since palladium is supported within an organic cage, the size of the active center composed of palladium is limited by the physical size of the cage. At this size, both the requirements for alkyne selectivity and activity are met, while reducing green oil production.

[0050] In the C3 fraction alkyne selective hydrogenation catalyst of this invention, Ag forms an alloy with Pd, and Ag atoms separate Pd atoms, increasing the spatial distance between adsorbed alkyne molecules. Consequently, the reaction intermediates after alkyne hydrogenation are more widely spaced, reducing the likelihood of intermediate coupling and thus decreasing the formation of green oil and improving the selectivity of alkyne hydrogenation. Because the C3 fraction alkyne selective hydrogenation catalyst of this invention significantly reduces byproducts, the catalyst prepared using this method may not even require regeneration. Attached Figure Description

[0051] Figure 1 This is a structural diagram of the organic cage synthesized in this invention. Detailed Implementation

[0052] The characterization method for the C3 fraction alkyne selective hydrogenation catalyst of the present invention during the preparation process is as follows:

[0053] The BET analyzer, purchased from Mack Company, USA, was used to determine the specific surface area, pore size distribution, and size of the organic cage; the contents of Pd and Ag in the catalyst were determined using an A240FS atomic absorption spectrometer.

[0054] The Agilent 7890A gas chromatograph measures the hydrogen and alkyne content and green oil production at the reactor outlet and inlet.

[0055] Example 1

[0056] Catalyst support: Commercially available clover-shaped alumina support with dimensions of φ2.2-2.8mm*3-10mm was used. After calcination at 1030℃ for 4 hours, the pore volume was 0.62cm³. 3 / g, specific surface area 62m² 2 / g. Weigh 100g of the carrier.

[0057] Catalyst preparation:

[0058] (1) Weigh 60g of lactic acid and mix it with 100g of calcined carrier. The mixture is then subjected to polymerization at 160℃ for 10 hours to obtain semi-finished catalyst A.

[0059] (2) Take 0.32g of tris(4-formylphenyl)amine and 0.16mg of dichloroacetic acid, dissolve them in 50mL of dichloroethane, and then mix them with semi-finished catalyst A. Stir and add a mixed solution of 0.21g of benzidine and 10mL of dichloroethane. Let the mixture stand at room temperature for 200 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry to obtain semi-finished catalyst B.

[0060] (3) Dissolve 0.68g of palladium acetate in 50mL of chloroform until the palladium acetate is completely dissolved and set aside.

[0061] (4) Immerse the semi-finished catalyst B in 50 mL of ethanol solution, then add the solution prepared in step (3) dropwise to the mixture of semi-finished catalyst B and ethanol, and stir for 30 hours. Then add 20 mL of ethanol solution dropwise to the above solution, stir at 70 °C for 1 hour, decant the solution, wash with deionized water, dry at 120 °C, and calcine at 280 °C for 8 hours to obtain semi-finished catalyst C.

[0062] (5) Weigh 0.94 g of silver nitrate and dissolve it in 57 g of deionized water. Immerse the semi-finished catalyst C in the prepared solution. After the solution is completely absorbed, let it stand for 4 hours and dry it at 120 °C. Then add 5 mL of 3% hydrazine hydrate solution to the above solution and stir it at room temperature for 1 hour. Pour off the solution, wash it with deionized water, and dry it at 120 °C to obtain C3 fraction alkyne selective hydrogenation catalyst 1.

[0063] Catalyst 1, prepared by atomic absorption spectrometry, was found to contain 0.3 wt% Pd and 0.6 wt% Ag. The size of the organic cage was 2.2 nm.

[0064] Comparative Example 1

[0065] Catalyst support: The support used in Example 1 is adopted.

[0066] Catalyst preparation: Compared with Example 1, Comparative Example 1 did not include the preparation process of steps (1) and (2), but was otherwise the same as Example 1.

[0067] (1) Dissolve 0.68g of palladium acetate in 50mL of chloroform until the palladium acetate is completely dissolved and set aside.

[0068] (2) Immerse the support in 50 mL of ethanol solution, then add the solution prepared in step (1) dropwise to the mixture of support and ethanol, and stir for 30 hours. Then add 20 mL of ethanol solution dropwise to the above solution, stir at 70 °C for 1 hour, decant the solution, wash with deionized water, dry at 120 °C, and calcine at 280 °C for 8 hours to obtain semi-finished catalyst B1.

[0069] (3) Weigh 0.94 g of silver nitrate and dissolve it in 57 g of deionized water. Immerse the semi-finished catalyst B1 in the prepared solution. After the solution is completely absorbed, let it stand for 4 hours and dry it at 120 °C. Then add 5 mL of 3% hydrazine hydrate solution to the above solution and stir it at room temperature for 1 hour. Pour off the solution, wash it with deionized water, and dry it at 120 °C to obtain C3 fraction alkyne selective hydrogenation catalyst 1-1.

[0070] The prepared catalyst 1-1 was determined by atomic absorption spectrometry to have a Pd content of 0.3 wt% and an Ag content of 0.6 wt%.

[0071] Example 2

[0072] Carrier: Commercially available clover-shaped alumina carrier with dimensions of φ2.2-2.8mm*3-10mm was used. After calcination at 1080℃ for 4 hours, the pore volume was 0.51cm³. 3 / g, specific surface area 31m² 2 / g. Weigh 100g of the carrier.

[0073] Catalyst preparation:

[0074] (1) Weigh 76.38g of lactic acid and mix it with 100g of calcined carrier. Add the mixture and carry out the polymerization reaction at 200℃ for 1 hour to obtain the semi-finished catalyst D.

[0075] (2) Take 338 mg of tris(4-formylphenyl)amine and 0.14 mg of trifluoroacetic acid, dissolve them in 50 mL of dichloroethane, and then mix them with semi-finished catalyst D. Stir and add a mixed solution of 266.5 mg of benzidine and 10 mL of dichloroethane. Let the mixture stand at room temperature for 100 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry to obtain semi-finished catalyst E.

[0076] (3) Dissolve 1.15g of palladium acetylacetonate in 50mL of chloroform and wait for it to dissolve completely before use.

[0077] (4) Immerse the semi-finished catalyst E in 50 mL of ethanol solution, then add the solution prepared in step (3) dropwise to the mixture of semi-finished catalyst E and ethanol, and stir for 30 hours. Then add 10 mL of formaldehyde solution dropwise to the above solution, stir at 60 °C for 1 hour, pour off the solution, wash with deionized water, dry at 120 °C, and calcine at 300 °C for 4 hours to obtain semi-finished catalyst F.

[0078] (5) Weigh 2.6g of silver nitrate and dissolve it in 68g of deionized water. Immerse the semi-finished catalyst F in the prepared solution. After the solution is completely absorbed, let it stand for 4 hours and dry it at 120℃. Then add 10mL of formaldehyde solution to the above solution and stir it at 60℃ for 1 hour. Pour off the solution, wash it with deionized water, and dry it at 120℃ to obtain C3 fraction alkyne selective hydrogenation catalyst 2.

[0079] Catalyst 2, prepared by atomic absorption spectrometry, was found to contain 0.3 wt% Pd and 1.5 wt% Ag. The size of the organic cage was 2.3 nm.

[0080] Comparative Example 2

[0081] Carrier: The same carrier as in Example 2 was used.

[0082] Catalyst preparation: The difference from Example 2 is that the Pd content is 0.5 wt%, and the rest is the same as in Example 2.

[0083] (1) Weigh 76.38g of lactic acid and mix it with 100g of calcined support. Add the mixture and keep it at 200℃ for 1 hour to obtain the semi-finished catalyst D1.

[0084] (2) Mix 338 mg of tri(4-formylphenyl)amine with 0.14 mg of trifluoroacetic acid, dissolve in 50 mL of dichloroethane, then mix with semi-finished catalyst D1, stir and add a mixed solution of 266.5 mg of benzidine and 10 mL of dichloroethane, let the mixture stand at room temperature for 100 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry to obtain semi-finished catalyst E1.

[0085] (3) Dissolve 1.48 g of palladium acetylacetonate in 50 mL of chloroform and wait for it to dissolve completely before use.

[0086] (4) Immerse the semi-finished catalyst E1 in 50 mL of ethanol solution, then add the solution prepared in step (3) dropwise to the mixture of semi-finished catalyst E1 and ethanol, and stir for 30 hours. Then add 10 mL of formaldehyde solution dropwise to the above solution, stir at 60 °C for 1 hour, pour off the solution, wash with deionized water, dry at 120 °C, and calcine at 300 °C for 4 hours to obtain semi-finished catalyst F1.

[0087] (5) Weigh 2.6g of silver nitrate and dissolve it in 68g of deionized water. Immerse the semi-finished catalyst F1 in the prepared solution. After the solution is completely absorbed, let it stand for 4 hours and dry it at 120℃. Then add 10mL of formaldehyde solution to the above solution and stir it at 60℃ for 1 hour. Pour off the solution, wash it with deionized water, and dry it at 120℃ to obtain C3 fraction alkyne selective hydrogenation catalyst 2-1.

[0088] Catalyst 2-1 was prepared by atomic absorption spectrometry, and the Pd content was found to be 0.5 wt% and the Ag content to be 1.5 wt%. The size of the organic cage was 2.3 nm.

[0089] Example 3

[0090] Carrier: Commercially available spherical alumina-titanium oxide carriers were used, with a titanium oxide content of 20% and a diameter of 3 mm. After calcination at 1050℃ for 4 hours, the pore volume was 0.54 cm³. 3 / g, specific surface area is 46m² 2 / g. Weigh 100g of the carrier.

[0091] Catalyst preparation:

[0092] (1) Weigh 74.66g of lactic acid and mix it with 100g of calcined support. Add the mixture and keep it at 260℃ for 1 hour to obtain the semi-finished catalyst H.

[0093] (2) Take 1.5g of tris(4-formylphenyl)amine and 0.33mg of trichloroacetic acid, dissolve them in 50mL of dichloroethane, and then mix them with the semi-finished catalyst H. Stir and add a mixed solution of 0.167g of benzidine and 10mL of trichloroethane. Let the mixture stand at room temperature for 150 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry to obtain the semi-finished catalyst J.

[0094] (3) Dissolve 1.15g of palladium acetylacetonate in 50mL of chloroform and wait for it to dissolve completely before use.

[0095] (4) Immerse the semi-finished catalyst J in 50 mL of methanol solution, then add the solution prepared in step (3) dropwise to the mixture of semi-finished catalyst J and ethanol, and stir for 30 hours. Then add 10 mL of formic acid solution dropwise to the above solution, heat and stir at 70°C for 2 hours, pour off the solution, wash with deionized water, dry at 120°C, and calcine at 400°C for 5 hours to obtain semi-finished catalyst K.

[0096] (5) Dissolve 1.7g of silver nitrate in 47g of deionized water, immerse the semi-finished catalyst K in the prepared solution, let it stand for 4 hours after the solution is completely absorbed, dry it at 120℃, add 5mL of 5% hydrazine hydrate solution, add it dropwise to the above solution, stir at room temperature for 1 hour, decan the solution, wash with deionized water, dry at 120℃ to obtain C3 fraction alkyne selective hydrogenation catalyst 3.

[0097] Catalyst 3 was prepared by atomic absorption spectrometry, and the Pd content was found to be 0.3 wt% and the Ag content to be 1.0 wt%. The size of the organic cage was 2.5 nm.

[0098] Comparative Example 3

[0099] Carrier: The same carrier as in Example 3 was used.

[0100] Catalyst preparation: The active component content is the same, and the catalyst is prepared using traditional methods.

[0101] (1) Weigh 0.5g of palladium chloride, dissolve it in hydrochloric acid, dilute the solution to 47g, adjust the pH to 2.3, mix it with 100g of calcined support, stir until the solution is completely absorbed, dry at 120°C, and calcine at 550°C to obtain the semi-finished catalyst H1.

[0102] (2) Dissolve 1.7g of silver nitrate in 47g of deionized water, immerse the semi-finished catalyst H1 in the prepared solution, and after the solution is completely absorbed, let it stand for 4 hours, dry at 120℃, and calcine at 550℃ to obtain C3 fraction alkyne selective hydrogenation catalyst 3-1.

[0103] The prepared catalyst 3-1 was determined by atomic absorption spectrometry to have a Pd content of 0.3 wt% and an Ag content of 1.0 wt%.

[0104] Example 4

[0105] Carrier: A commercially available toothed spherical alumina-magnesia carrier with a magnesium oxide content of 5 wt% and a diameter of 3 mm was used. After calcination at 1060℃ for 4 hours, the pore volume was 0.56 cm³. 3 / g, specific surface area is 45m² 2 / g. Weigh 100g of the carrier.

[0106] Catalyst preparation:

[0107] (1) Weigh 60.88g of lactic acid and mix it with 100g of calcined carrier. Add the mixture and carry out the polymerization reaction at 190℃ for 2 hours to obtain the semi-finished catalyst M.

[0108] (2) Take 1.48g of tri(4-formylphenyl)amine and 0.37mg of trifluoroacetic acid, dissolve them in 50mL of dichloroethane, and then mix them with the semi-finished catalyst M. Stir and add a mixed solution of 106.7mg of benzidine and 10mL of dichloroethane. Let the mixture stand at room temperature for 180 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry to obtain the semi-finished catalyst N.

[0109] (3) Dissolve 745 mg of palladium acetate in 50 mL of chloroform until the palladium acetate is completely dissolved and set aside.

[0110] (4) Immerse the semi-finished catalyst N in 50 mL of ethanol solution, then add the solution prepared in step (3) dropwise to the mixture of semi-finished catalyst N and ethanol, and stir for 30 hours. Then add 20 mL of methanol solution dropwise to the above solution, stir at 80 °C for 1 hour, decant the solution, wash with deionized water, dry at 120 °C, and calcine at 480 °C for 4 hours to obtain semi-finished catalyst P.

[0111] (5) Dissolve 1.9g of silver nitrate in 47g of deionized water, immerse the semi-finished catalyst P in the prepared solution, and after the solution is completely absorbed, let it stand for 4 hours, dry at 120℃, and calcine at 500℃ for 6 hours to obtain C3 fraction alkyne selective hydrogenation catalyst 4.

[0112] Catalyst 4 was prepared by atomic absorption spectrometry, and the Pd content was found to be 0.35 wt% and the Ag content to be 1.2 wt%. The size of the organic cage was 2.5 nm.

[0113] Comparative Example 4

[0114] Carrier: The same carrier as in Example 4 was used.

[0115] Catalyst preparation: The difference from Example 4 is that the calcination temperature in step (4) is 250°C, and the rest is the same as in Example 4.

[0116] (1) Weigh 60.88g of lactic acid and mix it with 100g of calcined support. Add the mixture and keep it at 190℃ for 2 hours to obtain the semi-finished catalyst M.

[0117] (2) Take 1.48g of tri(4-formylphenyl)amine and 0.37mg of trifluoroacetic acid, dissolve them in 50mL of dichloroethane, and then mix them with the semi-finished catalyst M. Stir and add a mixed solution of 106.7mg of benzidine and 10mL of dichloroethane. Let the mixture stand at room temperature for 180 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry to obtain the semi-finished catalyst N1.

[0118] (3) Dissolve 745 mg of palladium acetate in 50 mL of chloroform until the palladium acetate is completely dissolved and set aside.

[0119] (4) Immerse the semi-finished catalyst N in 50 mL of ethanol solution, then add the solution prepared in step (3) dropwise to the mixture of semi-finished catalyst N and ethanol, and stir for 30 hours. Then add 20 mL of methanol solution dropwise to the above solution, stir at 80 °C for 1 hour, decant the solution, wash with deionized water, dry at 120 °C, and calcine at 250 °C for 4 hours to obtain semi-finished catalyst P1.

[0120] (5) Dissolve 1.9g of silver nitrate in 47g of deionized water, immerse the semi-finished catalyst P1 in the prepared solution, and after the solution is completely absorbed, let it stand for 4 hours, dry at 120℃, and calcine at 500℃ for 6 hours to obtain C3 fraction alkyne selective hydrogenation catalyst 4-1.

[0121] Catalyst 4-1 was prepared by atomic absorption spectrometry, and the Pd content was found to be 0.35 wt% and the Ag content to be 1.2 wt%. The size of the organic cage was 2.5 nm.

[0122] Example 5

[0123] The carrier is a spherical alumina-magnesia carrier with a magnesium oxide content of 10% and a diameter of 2 mm. After calcination at 1060℃ for 4 hours, the pore volume is 0.55 cm³. 3 / g, specific surface area is 42m² 2 / g. Weigh 100g of the carrier.

[0124] Catalyst preparation:

[0125] (1) Weigh 56.52g of lactic acid and mix it with 100g of calcined carrier. Add the mixture and carry out the polymerization reaction at 190℃ for 2 hours to obtain the semi-finished catalyst Q.

[0126] (2) Take 1.25g of tris(4-formylphenyl)amine and 0.50mg of dichloroacetic acid, dissolve them in 50mL of dichloroethane, and then mix them with the semi-finished catalyst Q. Stir and add a mixed solution of 138mg of benzidine and 10mL of dichloroethane. Let the mixture stand at room temperature for 190 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry to obtain the semi-finished catalyst R.

[0127] (3) Dissolve 725 mg of palladium acetylacetonate in 50 mL of chloroform and wait for it to dissolve completely before use.

[0128] (4) Immerse the semi-finished catalyst R in 50 mL of methanol solution, then add the solution prepared in step (3) dropwise to the mixture of semi-finished catalyst R and methanol, and stir for 30 hours. Then add 10 mL of formic acid solution dropwise to the above solution, stir at 50 °C for 1 hour, pour off the solution, wash with deionized water, dry at 120 °C, and calcine at 380 °C for 4 hours to obtain semi-finished catalyst S.

[0129] (5) Dissolve 0.95g of silver nitrate in 52g of deionized water, immerse the semi-finished catalyst S in the prepared solution, let it stand for 4 hours after the solution is completely absorbed, dry it at 120℃, then add 20mL of formic acid solution dropwise to the above solution, stir at 50℃ for 1 hour, pour off the solution, wash with deionized water, and dry at 120℃ to obtain C3 fraction alkyne selective hydrogenation catalyst 5.

[0130] Catalyst 5 was prepared by atomic absorption spectrometry, and the Pd content was found to be 0.25 wt% and the Ag content to be 0.6 wt%. The size of the organic cage was 2.5 nm.

[0131] Comparative Example 5

[0132] Support: The catalyst support and preparation conditions are the same as in Example 5.

[0133] Catalyst preparation: The difference from Example 5 is that the tris(4-formylphenyl)amine used in step (2) is 4 times that in Example 5, and the rest is the same as in Example 5.

[0134] (1) Weigh 56.52g of lactic acid and mix it with 100g of calcined support. Add the mixture and keep it at 190℃ for 2 hours to obtain the semi-finished catalyst Q.

[0135] (2) Take 5g of tris(4-formylphenyl)amine and 0.50mg of dichloroacetic acid, dissolve them in 50mL of dichloroethane, then mix them with the semi-finished catalyst Q, stir and add a mixed solution of 138mg of benzidine and 10mL of dichloroethane, let the mixture stand at room temperature for 190 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry to obtain the semi-finished catalyst R1.

[0136] (3) Dissolve 725 mg of palladium acetylacetonate in 50 mL of chloroform and wait for it to dissolve completely before use.

[0137] (4) Immerse the semi-finished catalyst R1 in 50 mL of methanol solution, then add the solution prepared in step (3) dropwise to the mixture of semi-finished catalyst R1 and methanol, and stir for 30 hours. Then add 10 mL of formic acid solution dropwise to the above solution, stir at 50 °C for 1 hour, decant the solution, wash with deionized water, dry at 120 °C, and calcine at 380 °C for 4 hours to obtain semi-finished catalyst S1.

[0138] (5) Dissolve 0.95g of silver nitrate in 52g of deionized water, immerse the semi-finished catalyst S1 in the prepared solution, let it stand for 4 hours after the solution is completely absorbed, dry it at 120℃, then add 20mL of formic acid solution dropwise to the above solution, stir at 50℃ for 1 hour, pour off the solution, wash with deionized water, and dry at 120℃ to obtain C3 fraction alkyne selective hydrogenation catalyst 5-1.

[0139] Catalyst 5-1 was prepared by atomic absorption spectrometry, and the Pd content was found to be 0.25 wt% and the Ag content to be 0.6 wt%. The size of the organic cage was 1.6 nm.

[0140] Example 6

[0141] Carrier: A commercially available spherical carrier with 97 wt% alumina and 3 wt% titanium oxide, and a diameter of 3 mm, was used. After calcination at 1060℃ for 4 hours, the pore volume was 0.52 cm³. 3 / g, specific surface area 40m² 2 / g. Weigh 100g of the carrier.

[0142] Catalyst preparation:

[0143] (1) Weigh 56.44g of lactic acid and mix it with 100g of calcined support. The mixture is then subjected to polymerization at 190℃ for 1 hour to obtain the semi-finished catalyst U.

[0144] (2) Take 3.50g of tris(4-formylphenyl)amine and 0.70mg of trifluoroacetic acid, dissolve them in 50mL of dichloroethane, and then mix them with the semi-finished catalyst U. Stir and add a mixed solution of 350mg of benzidine and 10mL of dichloroethane. Let the mixture stand at room temperature for 100 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry to obtain the semi-finished catalyst V.

[0145] (3) Dissolve 750 mg of palladium acetate in 50 mL of dichloroethane until the palladium acetate is completely dissolved and set aside.

[0146] (4) Immerse the semi-finished catalyst V in 50 mL of ethanol solution, then add the solution prepared in step (3) dropwise to the mixture of semi-finished catalyst V and ethanol, and stir for 30 hours. Then add 30 mL of acetaldehyde solution dropwise to the above solution, stir at 60 °C for 1 hour, pour off the solution, wash with deionized water, dry at 120 °C, and calcine at 370 °C for 4 hours to obtain semi-finished catalyst W.

[0147] (5) Weigh 1.35g of silver nitrate and dissolve it in 55g of deionized water. Immerse the semi-finished catalyst W in the prepared solution. After the solution is completely absorbed, let it stand for 4 hours and dry it at 120℃. Then add 50mL of acetaldehyde solution to the above solution and stir it at 60℃ for 1 hour. Pour off the solution, wash it with deionized water, and dry it at 120℃ to obtain C3 fraction alkyne selective hydrogenation catalyst 6.

[0148] Catalyst 6, prepared by atomic absorption spectrometry, was found to contain 0.33 wt% Pd and 0.85 wt% Ag. The size of the organic cage was 2.5 nm.

[0149] Comparative Example 6

[0150] Carrier: The same carrier as in Example 6 was used.

[0151] Catalyst preparation: The difference from Example 6 is that in step (2) of this comparative example, phenylenediamine is used instead of benzidine in step (2) of Example 6, otherwise the same as in Example 6.

[0152] (1) Weigh 56.44g of lactic acid and mix it with 100g of calcined carrier. The mixture is then subjected to polymerization at 190℃ for 1 hour to obtain the semi-finished catalyst U1.

[0153] (2) Take 3.50g of tris(4-formylphenyl)amine and 0.70mg of trifluoroacetic acid, dissolve them in 50mL of dichloroethane, and then mix them with the semi-finished catalyst U1. Stir and add a mixed solution of 350mg of phenylenediamine and 10mL of dichloroethane. Let the mixture stand at room temperature for 100 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry to obtain the semi-finished catalyst V1.

[0154] (3) Dissolve 750 mg of palladium acetate in 50 mL of dichloroethane until the palladium acetate is completely dissolved and set aside.

[0155] (4) Immerse the semi-finished catalyst V1 in 50 mL of ethanol solution, then add the solution prepared in step (3) dropwise to the mixture of semi-finished catalyst V1 and ethanol, and stir for 30 hours. Then add 30 mL of acetaldehyde solution dropwise to the above solution, stir at 60 °C for 1 hour, decant the solution, wash with deionized water, dry at 120 °C, and calcine at 370 °C for 4 hours to obtain semi-finished catalyst W1.

[0156] (5) Weigh 1.35g of silver nitrate and dissolve it in 55g of deionized water. Immerse the semi-finished catalyst W1 in the prepared solution. After the solution is completely absorbed, let it stand for 4 hours and dry it at 120℃. Then add 50mL of acetaldehyde solution to the above solution and stir it at 60℃ for 1 hour. Pour off the solution, wash it with deionized water, and dry it at 120℃ to obtain C3 fraction alkyne selective hydrogenation catalyst 6-1.

[0157] Catalyst 6-1 was prepared by atomic absorption spectrometry, and the Pd content was found to be 0.33 wt% and the Ag content to be 0.85 wt%. The size of the organic cage was 1.5 nm.

[0158] Example 7

[0159] Carrier: Commercially available spherical alumina carrier with a diameter of 3 mm was used. After calcination at 1040℃ for 4 hours, the pore volume was 0.65 cm³. 3 / g, specific surface area 55m² 2 / g. Weigh 100g of the carrier.

[0160] Catalyst preparation:

[0161] (1) Weigh 74.66g of lactic acid and mix it with 100g of calcined carrier. Add the mixture and carry out the polymerization reaction at 210℃ for 2 hours to obtain the semi-finished catalyst X.

[0162] (2) Take 2.90g of tri(4-formylphenyl)amine and 0.72mg of trifluoroacetic acid, dissolve them in 50mL of dichloroethane, and then mix them with semi-finished catalyst X. Stir and add a mixed solution of 360mg of 2-chlorobiphenyldiamine and 10mL of dichloroethane. Let the mixture stand at room temperature for 120 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry to obtain semi-finished catalyst Y.

[0163] (3) Weigh 0.86 g of palladium acetylacetonate and dissolve it in 50 mL of dichloroethane. Wait until the palladium acetylacetonate is completely dissolved and set aside.

[0164] (4) Immerse the semi-finished catalyst Y in 50 mL of ethanol solution, then add the solution prepared in step (3) dropwise to the mixture of support and methanol, and stir for 30 hours. Then add 3 mL of 5% hydrazine hydrate solution dropwise to the above solution, stir for 1 hour at room temperature, decant the solution, wash with deionized water, dry at 120°C, and calcine at 300°C for 3 hours to obtain the semi-finished catalyst Z.

[0165] (5) Weigh 2.1g of silver nitrate and dissolve it in 67g of deionized water. Immerse the semi-finished catalyst Z in the prepared solution. After the solution is completely absorbed, let it stand for 4 hours and dry it at 120℃. Then add 3mL of 5% hydrazine hydrate solution to the above solution. Stir at room temperature for 1 hour, pour off the solution, wash with deionized water, and dry at 120℃ to obtain C3 fraction alkyne selective hydrogenation catalyst 7.

[0166] Catalyst 7 was prepared by atomic absorption spectrometry, and the Pd content was found to be 0.3 wt% and the Ag content to be 1.3 wt%. The size of the organic cage was 2.6 nm.

[0167] Comparative Example 7

[0168] Carrier: The same carrier as in Example 2 was used.

[0169] Catalyst preparation: The difference from Example 7 is that the amount of silver nitrate used in step (4) is 3 times that of Example 7, and the rest is the same as in Example 7.

[0170] (1) Weigh 74.66g of lactic acid and mix it with 100g of calcined carrier. Add the mixture and carry out the polymerization reaction at 210℃ for 2 hours to obtain the semi-finished catalyst X.

[0171] (2) Take 2.90g of tri(4-formylphenyl)amine and 0.72mg of trifluoroacetic acid, dissolve them in 50mL of dichloroethane, and then mix them with semi-finished catalyst X. Stir and add a mixed solution of 360mg of 2-chlorobiphenyldiamine and 10mL of dichloroethane. Let the mixture stand at room temperature for 120 hours, pour off the residue, wash with ethanol and deionized water respectively, and dry to obtain semi-finished catalyst Y.

[0172] (3) Weigh 0.86 g of palladium acetylacetonate and dissolve it in 50 mL of dichloroethane. Wait until the palladium acetylacetonate is completely dissolved and set aside.

[0173] (4) Immerse the semi-finished catalyst Y in 50 mL of ethanol solution, then add the solution prepared in step (3) dropwise to the mixture of support and methanol, and stir for 30 hours. Then add 3 mL of 5% hydrazine hydrate solution dropwise to the above solution, stir for 1 hour at room temperature, decant the solution, wash with deionized water, dry at 120°C, and calcine at 300°C for 3 hours to obtain the semi-finished catalyst Z.

[0174] (5) Weigh 6.3g of silver nitrate and dissolve it in 67g of deionized water. Immerse the semi-finished catalyst Z in the prepared solution. After the solution is completely absorbed, let it stand for 4 hours and dry it at 120℃. Then add 3mL of 5% hydrazine hydrate solution to the above solution. Stir at room temperature for 1 hour, pour off the solution, wash with deionized water, and dry at 120℃ to obtain C3 fraction alkyne selective hydrogenation catalyst 7-1.

[0175] Catalyst 7-1 was prepared by atomic absorption spectrometry, and the Pd content was found to be 0.3 wt% and the Ag content to be 3.9 wt%. The size of the organic cage was 2.6 nm.

[0176] The catalysts obtained in Examples 1-7 and Comparative Examples 1-7 were applied to the selective hydrogenation reaction of C3 distillate alkynes. The composition of the reactants is shown in Table 2, the performance evaluation results are shown in Table 3, and the calculation methods for each evaluation result are shown in Table 1.

[0177] Evaluation method: The catalyst loading amount in the fixed bed single-section reactor was 100 mL (record weight), the packing material was 50 mL, the volume hourly space velocity of the reactants was 60 / h, the operating pressure was 2.5 MPa, the hydrogen-to-acetylene ratio was 1.1-1.4, and the reactor inlet temperature was 35℃.

[0178] Table 1. Calculation method of evaluation results

[0179]

[0180]

[0181] Table 2 Composition of reactants

[0182] Propane (v%) 6～10 Propylene (v%) 80～85 Propyne (v%) 1～1.5 Propylene (v%) 1～2.0 C4 (v%) ＜0.5

[0183] The results of catalyst performance evaluation are shown in Table 3.

[0184] Table 3 Catalyst performance evaluation results

[0185]

[0186] As can be seen from the comparison of catalyst performance evaluation results in Table 3, compared with Example 1, the active components in Comparative Example 1 are partially aggregated in the pores due to the absence of polymers in the inner pores, resulting in very unsatisfactory alkyne conversion and selectivity.

[0187] In Comparative Example 2, due to the high palladium loading, some palladium overflowed from the organic cage and entered the support. Although it also formed hydrogenation-active atomic clusters during the calcination process, the active centers were located in the inner pores of the catalyst and had uneven size distribution, resulting in high activity but poor selectivity.

[0188] In Comparative Example 3, due to the use of a traditional catalyst preparation method, the size distribution of its active centers is wide, with some active centers larger than 3 nm and others smaller. Therefore, the activity, especially the selectivity, is significantly lower than that of Example 3, and the amount of green oil generated is much higher than that of Example 3. After 500 hours, the catalyst exhibits severe coking.

[0189] In Comparative Example 4, the calcination temperature in step (4) was low, so polylactic acid could not be completely decomposed, which blocked the pores of the catalyst and prevented the reactants from diffusing through the pores, resulting in very low activity.

[0190] In Comparative Example 5, the increased amount of tris(4-formylphenyl)amine led to an increase in the number of organic cages formed, resulting in an excessive number of active centers. Consequently, the size of the palladium active centers supported on individual organic cages decreased, leading to insufficient activity. Furthermore, excessively small active centers may also reduce the activation rate of hydrogen, resulting in insufficient hydrogen during the hydrogenation reaction, leading to the formation of more green oil and faster catalyst performance degradation.

[0191] In Comparative Example 6, the second monomer was phenylenediamine. The size of the synthesized organic cage was smaller than the optimal active center packing size required for alkyne hydrogenation, resulting in low initial activity. Some palladium could not enter the organic cage and could only be dispersed on the support, thus not contributing to the catalytic reaction.

[0192] In Comparative Example 7, the silver loading was excessive, and some of the original active sites were covered. Alkynes could not be effectively adsorbed on the catalyst surface. Although the initial selectivity was good, the catalyst activity was obviously insufficient from the beginning.

[0193] Of course, the present invention may have other embodiments and variations. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and variations according to the present invention, but these corresponding changes and variations should all fall within the protection scope of the claims of the present invention.

Claims

1. A C3 cut acetylene selective hydrogenation catalyst characterized by, The carrier of the catalyst is a carrier with alumina content of 80wt% or more, the specific surface area of the catalyst is 30-100m 2 / g; the catalyst further contains Pd and Ag, the content of Pd is 0.2-0.4wt% and the content of Ag is 0.6-3.0wt% based on 100% of the mass of the carrier, Pd is loaded in the organic cage; the organic cage is located in the interior of the catalyst and on the outer surface of the carrier, and the distance between the organic cage and the outer surface of the catalyst is less than or equal to 0.2mm, the size of the organic cage is 1.9-2.7nm.

2. The C3 cut acetylene selective hydrogenation catalyst of claim 1, wherein, The content of Ag is 0.6 to 2.0 wt%.

3. The C3 cut acetylene selective hydrogenation catalyst of claim 1, wherein, The alumina has the following crystal forms: θ, α, or a mixture thereof.

4. A process for the preparation of a carbon trimmer acetylene selective hydrogenation catalyst according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) The hydrophilic polymerizable monomer is mixed with the calcined support and then polymerized to obtain the semi-finished catalyst A; (2) Tris(4-formylphenyl)amine is mixed with haloacetic acid and dissolved in haloalkanes. Then it is mixed with semi-finished catalyst A, stirred and a mixed solution of benzidine or its substituted product and haloalkanes is added to obtain a mixture. The mixture is allowed to stand until the reaction is complete. The residue is poured off and washed with alcohol and deionized water respectively. After drying, semi-finished catalyst B is obtained. The substituents in the benzidine substituted product are halogens or alkanes. (3) Dissolve the organopalladium compound in a haloalkane until the organopalladium compound is completely dissolved and set aside for later use; (4) Immerse the semi-finished catalyst B in an alcohol solution, then add the solution prepared in step (3) to the mixture of semi-finished catalyst B and alcohol, stir at the same time, then add a reducing agent, heat and stir, wait until the surface of semi-finished catalyst B no longer changes color, pour off the solution, wash with deionized water, dry, and calcine to obtain semi-finished catalyst C. (5) Dissolve the soluble silver salt in deionized water or organic solvent, add the semi-finished catalyst C, and after the solution is completely absorbed, let it stand and dry. Then add the reducing agent, heat and stir to reduce the silver, pour off the solution, wash with deionized water, and dry to obtain the C3 fraction alkyne selective hydrogenation catalyst. In step (1), the hydrophilic polymerizable monomer is selected from at least one of lactic acid, acrylic acid, and methacrylic acid; In step (2), the number of moles of benzidine or its substituted derivatives is 1.2 to 2 times the number of moles of tris(4-formylphenyl)amine, and the mass ratio of tris(4-formylphenyl)amine to haloacetic acid is 2000 to 6000:

1. In step (4), the roasting temperature is 280-480℃ and the time is 3-8h.

5. The preparation method according to claim 4, characterized in that, In step (1), the mass ratio of the hydrophilic polymerizable monomer to the calcined carrier is 0.40-0.80:1; the polymer synthesized by the hydrophilic polymerizable monomer through polymerization reaction occupies the pores of the carrier, and the volume of the polymer is 80-95% of the pore volume of the carrier.

6. The preparation method according to claim 4, characterized in that, In step (3), the mass ratio of palladium to tris(4-formylphenyl)amine in the organic palladium compound is 0.63 to 4.8:1, based on the mass of palladium.

7. The preparation method according to claim 4, characterized in that, The carrier is at least one of the following shapes: spherical, cylindrical, clover-shaped, and four-leaf clover-shaped.

8. The preparation method according to claim 4, characterized in that, In step (2), the haloacetic acid is fluoroacetic acid or chloroacetic acid; in step (2), the haloalkane is fluoroalkane, chloroalkane or bromoalkane.

9. The production method according to claim 8, characterized by, The haloalkane is dichloroethane or trichloromethane.

10. The preparation method according to claim 4, characterized in that, In step (3), the organopalladium compound is at least one of palladium acetate and palladium acetylacetonate; in step (3), the haloalkane is at least one of chloroform and dichloroethane.

11. The preparation method according to claim 4, characterized in that, In step (4) or step (5), the reducing agent is at least one of methanol, formaldehyde, formic acid, ethanol, acetaldehyde, and hydrazine hydrate.

12. The method of claim 4, wherein, In step (4), the molar amount of the reducing agent is 1-3 for palladium.

13. The preparation method according to claim 4, characterized in that, In step (5), the soluble silver salt is silver nitrate or silver acetylacetone; in step (5), the soluble silver salt is added in an amount such that the Ag content in the catalyst is 0.6-3.0 wt%.

14. The method of claim 4, wherein, After the solution is completely absorbed in step (5), the mixture is left to stand, dried, and directly calcined at 500-550 DEG C to obtain a carbon fraction alkyne selective hydrogenation catalyst.

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