CN117463324A - Alkyne selective hydrogenation catalyst and preparation method thereof - Google Patents

Alkyne selective hydrogenation catalyst and preparation method thereof Download PDF

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CN117463324A
CN117463324A CN202210846584.9A CN202210846584A CN117463324A CN 117463324 A CN117463324 A CN 117463324A CN 202210846584 A CN202210846584 A CN 202210846584A CN 117463324 A CN117463324 A CN 117463324A
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catalyst
solution
semi
carrier
finished catalyst
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谭都平
向永生
张峰
谢元
车春霞
韩伟
温翯
李平智
柏介军
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Petrochina Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
    • B01J31/06—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/44—Palladium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/48—Silver or gold
    • B01J23/50—Silver
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/024—Multiple impregnation or coating
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/148—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound
    • C07C7/163—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound by hydrogenation
    • C07C7/167—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound by hydrogenation for removal of compounds containing a triple carbon-to-carbon bond

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Abstract

The invention provides an alkyne selective hydrogenation catalyst and a preparation method thereof. The carrier of the catalyst is alumina or mainly alumina; the active component of the catalyst at least contains Pd and Ag, the content of Pd is 0.02-0.04 percent and the content of Ag is 0.03-0.15 percent (preferably 0.05-0.15 percent) based on 100 percent of the mass of the carrier; the catalyst is provided with an organic cage, the distance between the organic cage and the outer surface of the catalyst is within 0.2mm, the size of the organic cage is 1.9-2.7nm, and Pd is loaded in the organic cage. The catalyst of the invention is used for the selective hydrogenation process of the carbon two fractions, and the yield of the butene can be reduced to less than 1/2 of that of the traditional catalyst.

Description

Alkyne selective hydrogenation catalyst and preparation method thereof
Technical Field
The invention relates to an alkyne selective hydrogenation catalyst and a preparation method thereof, and belongs to the technical field of catalyst preparation.
Background
Ethylene obtained by steam cracking petroleum hydrocarbon (such as ethane, naphtha, diesel oil, hydrogenated tail oil, etc.) contains 0.2-2.5% of acetylene by mass. When used in polymerization, acetylene in ethylene reduces the activity of the polymerization catalyst and affects the physical properties of the polymer, and must therefore be removed. At present, a selective hydrogenation method is generally adopted in industry to remove acetylene in ethylene, and the adopted catalyst is mainly noble metal catalyst such as Pd, pt, au and the like. In order to ensure that ethylene generated by acetylene hydrogenation and original ethylene in raw materials are not continuously hydrogenated to generate ethane, so that ethylene loss is caused, the higher hydrogenation selectivity of the catalyst is ensured, and better economic benefit can be obtained.
The second-carbon hydrogenation is to calculate the needed hydrogen according to the content of acetylene and match the hydrogen with hydrogenation materials, the mole ratio of the hydrogen to the acetylene is generally not more than 2, and the hydrogen is less, so that the dimerization reaction of the acetylene is easy to occur, the fourth-carbon fraction is generated, and the fourth-carbon fraction is further polymerized to generate an oligomer with wider molecular weight, commonly called as green oil. Green oil adsorbs on the catalyst surface and further forms coke, blocking catalyst pore channels, preventing the reactant from diffusing to the surface of the active center of the catalyst, thereby causing the activity of the catalyst to be reduced.
The noble metal catalyst has higher activity, but green oil is easy to generate in the use process, so that the catalyst is coked and deactivated, and the stability and the service life of the catalyst are affected. CN200810119385.8 discloses a non-noble metal supported selective hydrogenation catalyst, a preparation method and application thereof, comprising a carrier, and a main active component and a co-active component supported on the carrier, wherein the main active component is Ni, the co-active 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 co-active component are both in amorphous form, the average particle size is less than 10nm, and the carrier is a porous material without oxidizing property; and the catalyst is prepared by a micro-emulsification method.
US4404124 prepares a selective hydrogenation catalyst with active component shell distribution by a step-by-step impregnation method, and can be applied to selective hydrogenation of carbon two fractions to eliminate acetylene in ethylene. US5587348 uses alumina as a carrier, adds promoter silver and palladium, and adds fluorine chemically bonded with alkali metal to prepare a carbon hydrogenation catalyst with excellent performance. The catalyst has the characteristics of reducing green oil generation, improving ethylene selectivity and reducing the generation amount of oxygen-containing compounds.
CN1736589 reports a Pd/gamma-Al prepared by a complete adsorption impregnation method 2 O 3 And a hydrogenation catalyst is selected, and the green oil is produced in a large amount in the use process of the catalyst. CN200810114744.0 discloses an unsaturated hydrocarbon selective hydrogenation catalyst and a preparation method thereof. The catalyst takes alumina as a carrier and palladium as an active component, and the rare earth, alkaline earth metal and fluorine are added to improve the impurity resistance and coking resistance of the catalyst, but the selectivity of the catalyst is not ideal.
The catalyst prepared by the method adopts the catalyst with single pore diameter distribution, and the catalyst selectivity is poor under the influence of internal diffusion in the fixed bed reaction process. The carrier with double-peak pore distribution ensures high activity of the catalyst, and the existence of macropores can reduce the influence of internal diffusion and improve the selectivity of the catalyst. ZL971187339 discloses a hydrogenation catalyst, wherein the carrier is a honeycomb carrier, and is a large-aperture carrier, so that the selectivity of the catalyst is effectively improved. CN1129606a discloses a hydrocarbon conversion catalyst, the carrier catalyst of which comprises alumina, nickel oxide, iron oxide, etc., and the catalyst comprises two kinds of pores, one of which is used for improving the catalytic reaction surface, and the other is beneficial to diffusion. CN101433842a discloses a hydrogenation catalyst, which is characterized in that the catalyst has a bimodal pore distribution, the most probable radius of the small pore portion is 2-50nm, the most probable radius of the large pore portion is 100-500nm, and the catalyst has good hydrogenation activity and good selectivity and large ethylene increment at the same time of the bimodal pore distribution.
In the carbon di-hydrogenation reaction, green oil generation and catalyst coking are important factors affecting catalyst service life. The activity, selectivity and service life of the catalyst form the overall performance of the catalyst, and the methods listed above either provide a better approach to improving the activity and selectivity of the catalyst, but do not solve the problem that the catalyst is easy to coke, or solve the problem that the catalyst is easy to generate green oil and coke, but do not solve the problem of selectivity. The carrier with a macroporous structure can improve the selectivity, but larger molecules generated by polymerization and chain growth reaction are easy to accumulate in macropores of the carrier, so that the catalyst is coked and deactivated, and the service life of the catalyst is influenced.
In the carbon two selective hydrogenation reaction, pd is used as the main active component, and Pd is used as Pd in the traditional impregnation preparation process of the catalyst 2+ Or [ PdCl ] 4 ] 2- The ionic species is bound to the support and during activation Pd aggregates to become active sites. Due to the aggregation of Pd during activation, it is a kinetic-governed random process, that is, the size of each active center is difficult to control in advance.
Previous studies have found a selective hydrogenation process for acetylene which is: first one acetylene molecule is combined with 1 hydrogen atom to form vinyl, which is then combined with a hydrogen atom to form ethylene, or 2 vinyl groups are coupled to form butadiene. Since butadiene can undergo a series of polymerization reactions to form green oil and then coke, inhibition of butadiene formation becomes a key to preventing coking of the carbon two selective hydrogenation catalyst.
It is apparent that if 2 vinyl groups are formed simultaneously at 1 catalyst activity center, the probability of butadiene formation increases greatly. It was also found that the large size of the active center increases the yield of butadiene. To prevent large active center sizes, there are generally 2 approaches: one is to reduce the amount of active ingredient and the other is to enlarge the dispersion area of the active ingredient. However, the load of the active components is reduced, the number of active centers is possibly insufficient, the hydrogenation activity is insufficient, acetylene cannot be completely removed, the hydrogenation product is unqualified, and the economic loss is extremely large.
The expansion of the active component loading area, the active center with part not located near the catalyst surface, results in poor catalyst selectivity and great ethylene loss in the hydrogenation process.
In order to prepare catalysts with narrow particle size distribution, some researchers have synthesized a series of organic cages with three-dimensional structures, which have fixed sizes and can be used for fixing metals, thereby preparing catalysts with highly dispersed metal clusters. Qiang Song et al synthesized an organic Three-dimensional organic cage, and reported that organic cage supported metallic palladium was used for hydrogenation of nitrobenzene. At present, the three-dimensional organic cages are used for full hydrogenation or homogeneous hydrogenation after being loaded with active components and uniformly distributed on a carrier in a solution. In the case of selective hydrogenation, not only the size of the active center affects the reaction, but also the distribution of the active components in the catalyst has a great influence on the reaction result, and the catalyst with uniformly distributed active components is not suitable for selective hydrogenation reaction.
There are many studies on the hydrogenation of noble metal monoatomic catalysts, but for the hydrogenation of alkynes, there is a considerable distance between the catalyst and the practical application. The reason for this is: in the active center of hydrogenation reaction, 2 processes need to be completed, wherein 1 is the activation of alkyne molecules, namely electron pairs of alkyne molecules double bonds enter into empty orbitals of active center atoms, and the active center atoms feed back the electron pairs to the opposite bond orbitals of alkyne molecules, so that double bond energy is reduced, double bonds are activated, and breakage occurs; at the same time, the same process is required for hydrogen molecules to activate hydrogen into hydrogen atoms. For a single-atom active center, the physical size of a single atom is limited, and meanwhile, the 2 processes are difficult to finish, so that the reaction process is slower, and the requirements of practical application are difficult to meet. Therefore, it is a natural matter that the activity neutrality needs to have a certain physical size, and in fact, for the palladium catalyst, since a large amount of hydrogen can be absorbed inside the stacked structure, the activation of hydrogen and the transfer of hydrogen atoms are completed inside the stacked structure of palladium, and thus the activity is higher than that of the active component capable of adsorbing hydrogen only on the surface.
ZL101433842A discloses a hydrogenation catalyst, which is characterized in that the catalyst has double-peak hole distribution, the most probable radius of a small hole part is 2-50nm, the most probable radius of a large hole part is 100-500nm, and the catalyst has good hydrogenation activity, good selectivity and large ethylene increment at the same time because of the double-peak hole distribution. The disadvantages of this technique or the shortcomings with respect to the present invention: the main active components of the catalyst are loaded by adopting a solution method, the dispersity is high, the aggregation of the active components is a random process controlled by dynamics in the roasting process, the formed active center has wide scale distribution, and the active center has optimal activity selectivity when the active center scale is 2-3nm, but the control of the active center scale at 2-3nm is difficult by means of a simple roasting process. The scale of part of active center is too small, and the hydrogenation activity is not possessed; part of the active center is oversized, the hydrogenation activity is good and the selectivity is poor.
Disclosure of Invention
In order to solve the technical problems, the invention aims to provide an alkyne selective hydrogenation catalyst and a preparation method thereof, wherein the catalyst has lower butadiene yield or butene yield.
In order to achieve the above purpose, the invention provides an alkyne selective hydrogenation catalyst, wherein the carrier of the catalyst is alumina or mainly alumina;
The active component of the catalyst contains Pd and Ag, the content of Pd is 0.02-0.04 percent and the content of Ag is 0.03-0.15 percent (preferably 0.05-0.15 percent) based on 100 percent of the mass of the carrier;
the catalyst is provided with an organic cage, the distance between the organic cage and the outer surface of the catalyst is within 0.2mm, the size of the organic cage is 1.9-2.7nm, and Pd is loaded in the organic cage.
The catalyst of the invention synthesizes organic cages with regular structures on the outer surface of the carrier in situ, the size of the cages is 1.9-2.7nm, and active components are loaded in the organic cages. The size of the active center is also in the range of 1.9-2.7nm and uniform, which can meet the activity requirement without the excessive active center, and reduces the probability of forming 2 vinyl groups at the same time in one active center.
In the catalyst of the invention, ag can form an alloy with Pd to improve selectivity of acetylene hydrogenation, and in particular, the role of Ag has two roles: firstly, silver atoms separate palladium atoms, so that the space distance of adsorbed acetylene molecules is increased, the mutual distance between corresponding reaction intermediates after acetylene hydrogenation is larger, strong adsorption species of acetylene are not formed, vinyl is further formed, intermediate coupling is not easy to occur, and therefore, the formation of green oil is reduced, which is called geometric action; and the second is that electrons of the outer layer S of silver enter the empty track of palladium, and reduce the adsorption effect of palladium on ethylene, which is called electron effect.
According to a specific embodiment of the present invention, preferably, the specific surface area of the catalyst is 15-40m 2 /g。
According to a specific embodiment of the present invention, preferably, the alumina in the carrier is in the form of theta, alpha or a mixture thereof; the alumina content in the catalyst carrier is more than 80%.
According to a specific embodiment of the present invention, preferably, the support also contains other metal oxides, such as titanium oxide and/or magnesium oxide.
The invention also provides a preparation method of the catalyst, which mainly comprises the following steps:
(1) Forming a polar polymer within the support, the polymer occupying greater than 80% of the pore volume of the support;
(2) In-situ synthesizing an organic cage in the rest holes of the carrier;
(3) Loading active component palladium in an organic cage;
(4) Roasting to decompose the organic polymer synthesized in the step (1);
(5) And loading auxiliary active component silver to obtain the required catalyst.
According to a specific embodiment of the present invention, preferably, the above preparation method comprises the following specific steps:
(1) Mixing hydrophilic polymerizable monomer with a roasted carrier, and polymerizing at a certain temperature to obtain a first semi-finished catalyst, wherein the volume of a polymer synthesized by the hydrophilic monomer is 80-95% of the pore volume of the carrier;
(2) Mixing tri (4-formylphenyl) amine and halogenated acetic acid, dissolving in halogenated acetic acid, then mixing with a first semi-finished catalyst, stirring and dropwise adding a mixed solution of a phenyl diamine substituent and halogenated acetic acid, standing the mixture, pouring out residual liquid after the reaction is completed, washing with alcohol and deionized water respectively, and drying to obtain a second semi-finished catalyst;
wherein the molar ratio of the phenyl diamine substituent to the tris (4-formylphenyl) amine is 1.2-2:1, the mass ratio of the tri (4-formylphenyl) amine to the halogenated acetic acid is 2000-6000:1;
(3) Dissolving an organic palladium compound in an organic solvent to obtain a precursor solution of palladium, wherein the mass ratio of the organic palladium compound to tris (4-formylphenyl) amine is 0.63-4.8:1;
(4) Immersing the second semi-finished catalyst into an alcohol solution, dropwise adding a palladium precursor solution into a mixture of the second semi-finished catalyst and alcohol, stirring at the same time, dropwise adding a reducing agent, heating and stirring until the surface of the second semi-finished catalyst is not discolored, pouring out the solution, washing with deionized water, drying, and roasting at a temperature at which the polymer synthesized in the step (1) can be decomposed to obtain a third semi-finished catalyst;
(5) Dissolving soluble silver salt in deionized water or an organic solvent to obtain a silver-containing impregnating solution, immersing a third semi-finished catalyst in the silver-containing impregnating solution, and standing after the third semi-finished catalyst is fully absorbed;
And (3) dropwise adding a reducing agent to reduce silver, pouring the solution, washing with deionized water, and drying to obtain the catalyst, or, without reduction, pouring the solution, washing with deionized water, drying, and roasting to obtain the catalyst.
According to the specific embodiment of the invention, in order to ensure that the organic cage is positioned on the outer surface of the carrier, the invention uses other mediums to occupy the pore canal inside the carrier in advance, so that the organic cage is synthesized in the pore near the outer surface, and the invention is not limited to the specific kind of monomer used for synthesizing the organic cage, as long as the size of the synthesized organic cage is between 1.9 and 2.7 nm. Preferably, in step (1), the hydrophilic polymerizable monomer is a monomer containing a carbonyl group and/or a carboxyl group and capable of undergoing polymerization or condensation reaction, more preferably comprising lactic acid, acrylic acid or formaldehyde.
According to a specific embodiment of the present invention, the certain temperature in step (1) means the temperature at which the thermal condensation reaction or bulk polymerization of the monomer occurs, and is generally 80 to 200℃depending on the monomers.
According to a specific embodiment of the present invention, the carrier in step (1) may be spherical, cylindrical, clover, and the like.
According to a specific embodiment of the present invention, preferably, in step (2), the phenylenediamine is a biphenyldiamine or a substituent thereof, preferably the phenylenediamine is a biphenyldiamine or a substituent thereof, and the substituent of the substituent is preferably halogen or alkyl.
According to a specific embodiment of the present invention, the haloacetic acid is a catalyst for the reaction of tris (4-formylphenyl) amine with phenyl diamine, preferably in step (2) the haloacetic acid comprises fluoroacetic acid or chloroacetic acid, preferably trifluoroacetic acid or dichloroacetic acid.
According to a specific embodiment of the present invention, the haloalkane is a solvent required for the reaction, preferably in step (2) the haloalkane comprises a fluoroalkyl, chloroalkane or bromoalkane, preferably a halomethane or haloethane, more preferably dichloroethane or trichloromethane.
According to a specific embodiment of the present invention, preferably, in step (3), the organic palladium compound includes one or a combination of two or more of palladium acetate, palladium lactate and palladium acetylacetonate.
According to a specific embodiment of the present invention, preferably, in step (4), the alcohol comprises ethanol or methanol, more preferably ethanol.
According to a specific embodiment of the present invention, preferably, in step (4) and step (5), the reducing agent is a reducing compound, more preferably one or a combination of two or more of methanol, formaldehyde, formic acid, ethanol, acetaldehyde, hydrazine hydrate.
According to a specific embodiment of the present invention, preferably, in step (5), the soluble silver salt is a silver salt soluble in water or an organic solvent, preferably silver nitrate soluble in water and/or silver acetylacetonate soluble in an organic solvent, or the like. Silver is supported by a solution process, such as a saturated impregnation process.
According to an embodiment of the present invention, in step (5), when reduction is not performed after silver loading, the oxidation catalyst may be prepared by calcination at 450 ℃ or less.
The invention also provides a carbon two-fraction selective hydrogenation process which is carried out by adopting the catalyst.
In conventional carbon two-fraction selective hydrogenation catalysts, the selective hydrogenation of acetylene occurs in the main active center of Pd composition, and activation is a high temperature calcination process during catalyst preparation, in which the metal salt typically decomposes into metal oxides, which form clusters. However, the aggregation of the active components during the calcination is a random process and can only be formed into active centers with a large scale of normal distribution of 1-3 nm. The active center is small in size, so that the activity is insufficient; the large scale tends to result in the simultaneous formation of 2 vinyl groups and further butadiene.
The research of the invention finds that: as long as the amount of the active component and the loading conditions are unchanged, the reaction temperature and the hydrogen amount are changed, the butadiene production amount is basically fixed relative to the amount of acetylene at the inlet, and the distribution of the active center size is influenced by statistical rules. In the actual reaction, since butadiene is hydrogenated, butene is the most or all of the butenes.
Therefore, the catalyst provided by the invention has active centers with uniform size distribution, can reduce the formation of byproducts, can further prolong the operation time of the catalyst under high selectivity, and has very important significance for the carbon two-fraction selective hydrogenation process.
The catalyst provided by the invention has the following characteristics: since palladium is supported in an organic cage, the active center composed of palladium is limited by the physical size of the cage, and its size is the largest size of the cage. This size meets the activity requirement for acetylene selectivity, but the probability of forming 2 vinyl groups simultaneously in one active center is greatly reduced, and the butene yield can be reduced to less than 1/2 of that of the traditional catalyst. The catalyst can be applied to a process for removing acetylene by selective hydrogenation of carbon two fractions. Moreover, the organic cage is positioned on the outer surface of the catalyst, so that the influence of inner diffusion limitation on catalytic reaction is avoided, and the selectivity of the catalyst is good. The catalyst of the invention is used for the selective hydrogenation process of the carbon two fractions, the byproducts are greatly reduced, and the catalyst can not even need to be regenerated.
Drawings
FIG. 1 is a plot of pore size of the synthetic organic cage of example 1 as determined by the BET method.
Detailed Description
The technical solution of the present invention will be described in detail below for a clearer understanding of technical features, objects and advantageous effects of the present invention, but should not be construed as limiting the scope of the present invention.
The catalyst of the invention adopts the following characterization method in the preparation process: BET testers, in the united states of america, measure specific surface area and pore size distribution. The Pd and Ag contents in the catalyst were measured on an A240FS atomic absorption spectrometer.
Raw materials: tris (4-formylphenyl) amine, dichloroacetic acid, dichloroethane, biphenyldiamine, hydrazine hydrate, ethanol, methanol, acetic acid, formic acid, formaldehyde, lactic acid, acrylic acid, palladium acetate, palladium acetylacetonate, silver nitrate, analytically pure, shanghai national pharmaceutical group company; alumina, shandong aluminum products group Co.
Example 1
The present embodiment provides a catalyst wherein:
catalyst carrier: a commercially available spherical alumina carrier was used, 4mm in diameter. After roasting for 4 hours at 1050 ℃, the pore volume is 0.6m 3 Per gram, specific surface area 40.15m 2 And/g. 100g of the carrier was weighed.
And (3) preparing a catalyst:
(1) Weighing 60g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 160 ℃ for 10 hours to obtain a semi-finished catalyst A;
(2) Mixing 31.7mg of tris (4-formylphenyl) amine with 0.0158mg of dichloroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst A, stirring, dropwise adding a mixed solution of 34.65mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 200 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst B;
(3) Dissolving 0.042g of palladium acetate in 50mL of glacial acetic acid, and keeping the palladium acetate completely dissolved for later use;
(4) Immersing a semi-finished catalyst B in 50mL of 30% ethanol solution, dropwise adding the solution prepared in the step (3) into a mixture of the semi-finished catalyst B and ethanol, stirring at the same time, dropwise adding 20mL of 30% ethanol solution into the mixture, stirring at 70 ℃ for 1 hour, pouring out the solution, washing with deionized water, drying at 120 ℃, and roasting at 280 ℃ for 8 hours to obtain a semi-finished catalyst C;
(5) Weighing 0.047g of silver nitrate, dissolving into 57g of deionized water to obtain an impregnating solution containing Ag, immersing a semi-finished catalyst C into the impregnating solution containing Ag, standing for 4 hours after the solution is fully absorbed, dripping 5ml of hydrazine hydrate solution with the concentration of 5% into the solution, stirring for 1 hour at room temperature, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.
The catalyst prepared in example 1 had a Pd content of 0.02% and an Ag content of 0.03% as measured by atomic absorption spectrometry.
The pore size results of the synthetic organic cage of example 1, as determined by the BET method, are shown in FIG. 1. As can be seen from FIG. 1, the maximum pore diameter is 2.43nm, and the minimum pore diameter is 1.95nm.
Comparative example 1
This comparative example provides a catalyst wherein:
catalyst carrier: the carrier used in example 1 was used.
And (3) preparing a catalyst: the preparation conditions were the same as in example 1, except that: step (1) of example 1 is absent;
(1) Mixing 31.7mg of tris (4-formylphenyl) amine with 0.0158mg of dichloroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a carrier, stirring and dropwise adding a mixed solution of 34.65mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 200 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst A1;
(2) Dissolving 0.042g of palladium acetate in 50ml of glacial acetic acid until the palladium acetate is completely dissolved for later use;
(3) Immersing the semi-finished catalyst A1 in 50ml of 30% ethanol solution, dripping the solution prepared in the step (2) into a mixture of the semi-finished catalyst A1 and ethanol, stirring, dripping 20ml of 30% ethanol solution into the mixture, stirring at 70 ℃ for 1 hour, pouring out the solution, washing with deionized water, drying at 120 ℃, and roasting at 280 ℃ for 8 hours to obtain a semi-finished catalyst B1;
(4) Weighing 0.047g of silver nitrate, dissolving the silver nitrate into 57g of deionized water to obtain an impregnating solution containing Ag, immersing a semi-finished catalyst B1 into the impregnating solution containing Ag, standing for 4 hours after the solution is fully absorbed, dripping 5ml of hydrazine hydrate solution with the concentration of 5% into the solution, stirring for 1 hour at room temperature, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the comparative catalyst 1.
The catalyst prepared in comparative example 1 had a Pd content of 0.02% and an Ag content of 0.03% as measured by atomic absorption spectrometry.
Example 2
The present embodiment provides a catalyst wherein:
and (3) a carrier: a commercially available spherical alumina carrier was used, 3mm in diameter. After baking for 4 hours at 1150 ℃, the water absorption pore volume is 0.65m 3 Per gram, specific surface area of 15.07m 2 And/g. 100g of the carrier was weighed.
And (3) preparing a catalyst:
(1) Weighing 76.38g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 200 ℃ for 1 hour to obtain a semi-finished catalyst D;
(2) Mixing 8.33mg of tri (4-formylphenyl) amine with 0.0014mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst D, stirring, dropwise adding a mixed solution of 5.46mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 100 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst E;
(3) 0.115g of palladium acetylacetonate is dissolved in 50ml of chloroform and the palladium acetylacetonate is completely dissolved for later use.
(4) Immersing a semi-finished catalyst E in 50ml of 30% ethanol solution, dripping the solution prepared in the step (3) into a mixture of the semi-finished catalyst E and ethanol, stirring at the same time, dripping 10ml of 40% formaldehyde solution into the mixture, stirring at 60 ℃ for 1 hour, pouring out the solution, washing with deionized water, drying at 120 ℃, and roasting at 300 ℃ for 2 hours to obtain a semi-finished catalyst F;
(5) Weighing 0.24g of silver nitrate, dissolving the silver nitrate into 68g of deionized water to obtain an impregnating solution containing Ag, immersing a semi-finished catalyst F into the impregnating solution containing Ag, standing for 4 hours after the solution is fully absorbed, pouring the solution out, washing with deionized water, drying at 120 ℃, and roasting at 500 ℃ for 4 hours to obtain the required oxidation state catalyst.
The catalyst prepared in example 2 had a Pd content of 0.04% and an Ag content of 0.15% as measured by atomic absorption spectrometry.
And (3) reduction of a catalyst: the oxidation state catalyst is placed in hydrogen gas before use, and is reduced for 4 hours at 120 ℃ and the hydrogen gas space velocity is 100 hours -1 。
Comparative example 2
This comparative example provides a catalyst wherein:
And (3) a carrier: the same carrier as in example 2 was used.
And (3) preparing a catalyst: the preparation conditions were the same as in example 2, except that the constant temperature in step (1) was 260 ℃;
(1) Weighing 74.66g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 260 ℃ for 1 hour to obtain a semi-finished catalyst D1;
(2) Mixing 8.33mg of tris (4-formylphenyl) amine with 0.0014mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst D, stirring, dropwise adding a mixed solution of 5.46mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 100 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst E1;
(3) Dissolving 0.115g of palladium acetylacetonate in 50ml of chloroform, and keeping until the palladium acetylacetonate is completely dissolved for later use;
(4) Immersing a semi-finished catalyst E1 in 50ml of 30% ethanol solution, dripping the solution prepared in the step (3) into a mixture of the semi-finished catalyst E1 and ethanol, stirring at the same time, dripping 10ml of 40% formaldehyde solution into the mixture, stirring at 60 ℃ for 1 hour, pouring out the solution, washing with deionized water, drying at 120 ℃, and roasting at 300 ℃ for 2 hours to obtain a semi-finished catalyst F1;
(5) Weighing 0.24g of silver nitrate, dissolving the silver nitrate into 68g of deionized water to obtain an impregnating solution containing Ag, immersing a semi-finished catalyst F1 into the impregnating solution containing Ag, standing for 4 hours after the solution is fully absorbed, pouring out the solution, washing with deionized water, drying at 120 ℃, and roasting at 500 ℃ for 4 hours to obtain the required oxidation state catalyst.
The catalyst prepared in comparative example 2 had a Pd content of 0.04% and an Ag content of 0.15% as measured by atomic absorption spectrometry.
And (3) reduction of a catalyst: the oxidation state catalyst is placed in hydrogen gas before use, and is reduced for 4 hours at 120 ℃ and the hydrogen gas space velocity is 100 hours -1 。
Example 3
The present embodiment provides a catalyst wherein:
and (3) a carrier: a commercially available spherical alumina-titania carrier was used, with a titania content of 20% and a diameter of 4mm. After roasting for 4 hours at 1100 ℃, the pore volume is 0.47m 3 Per gram, specific surface area of 30.64m 2 And/g. 100g of the carrier was weighed.
And (3) preparing a catalyst:
(1) Weighing 10.5g of acrylic acid, 27.2g of water, 0.01g of potassium hypophosphite monohydrate, 0.023g of copper acetate monohydrate, 0.16ml of 30% hydrogen peroxide as an initiator, uniformly mixing, adding 100g of calcined carrier, transferring the solution into a reflux bottle after the solution is completely absorbed, heating to 80 ℃ under stirring, and keeping the temperature for 1 hour to obtain a semi-finished catalyst H;
(2) Mixing 30mg of tris (4-formylphenyl) amine with 0.0075mg of trichloroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst H, stirring and dropwise adding a mixed solution of 9.85mg of biphenyldiamine and 10ml of trichloroethane, standing the mixture at room temperature for 150 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst J;
(3) 0.0859g of palladium acetylacetonate is dissolved in 50ml of chloroform and the palladium acetylacetonate is completely dissolved for later use.
(4) Immersing a catalyst J in 50ml of a methanol solution with the concentration of 80% or more, dropwise adding the solution prepared in the step (3) into a mixture of a semi-finished catalyst J and methanol, stirring the mixture, dropwise adding 10ml of a formic acid solution with the concentration of 50% or so into the solution, heating and stirring the mixture at 70 ℃ for 2 hours, pouring the solution, washing the mixture with deionized water, drying the mixture at 120 ℃, and roasting the mixture at 400 ℃ for 2 hours to obtain a semi-finished catalyst K;
(5) Dissolving 0.16g of silver nitrate into 47g of ionized water to obtain an impregnating solution containing Ag, immersing a semi-finished catalyst K into the impregnating solution containing Ag, standing for 4 hours after the solution is fully absorbed, dropwise adding 5ml of hydrazine hydrate solution with the concentration of 10% into the solution, stirring for 1 hour at room temperature, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.
The catalyst prepared in example 3 had a Pd content of 0.03% and an Ag content of 0.1% as measured by atomic absorption spectrometry.
Comparative example 3
This comparative example provides a catalyst wherein:
and (3) a carrier: the same carrier as in example 3, i.e., a commercially available spherical alumina-titania carrier, was used, with a titania content of 20% and a diameter of 4mm. After baking for 4h at 1150 ℃, the pore volume is 0.47m 3 Per gram, specific surface area of 30.64m 2 And/g. 100g of the carrier was weighed.
And (3) preparing a catalyst: the active components are the same in content, and the catalyst is prepared by adopting a traditional method. The specific process is as follows:
(1) Weighing 0.5g of palladium chloride, dissolving in hydrochloric acid, diluting the solution to 47g, regulating the pH to 2.5, mixing with 100g of roasted carrier, stirring until the solution is completely absorbed, drying at 120 ℃, and roasting at 550 ℃ to obtain a semi-finished catalyst H1;
(2) And (3) dissolving 0.16g of silver nitrate into 47g of deionized water to obtain an Ag impregnation solution, immersing the semi-finished catalyst H1 into the prepared Ag impregnation solution, standing for 4 hours after the solution is fully absorbed, drying at 120 ℃, and roasting at 550 ℃ to obtain the required catalyst.
The catalyst prepared in comparative example 3 had a Pd content of 0.03% and an Ag content of 0.1% as measured by atomic absorption spectrometry.
Example 4
The present embodiment provides a catalyst wherein:
and (3) a carrier: the commercial tooth-ball type alumina-magnesia carrier is adopted, the magnesia content is 5 percent, and the diameter is 3mm. Roasting for 4 hours at 1130 ℃ and then obtaining the pore volume of 0.52m 3 Per gram, specific surface area of 25.67m 2 And/g. 100g of the carrier was weighed.
And (3) preparing a catalyst:
(1) Weighing 60.88g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 190 ℃ for 2 hours to obtain a semi-finished catalyst M;
(2) Mixing 17.8mg of tris (4-formylphenyl) amine with 0.0059mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst M, stirring, dropwise adding a mixed solution of 14.59mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 180 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst N;
(3) Palladium acetate 74.31mg was dissolved in 50ml of chloroform, and the solution was prepared after palladium acetate was completely dissolved.
(4) Immersing a semi-finished catalyst N in 50ml of 30% ethanol solution, dripping the solution prepared in the step (3) into a mixture of the semi-finished catalyst N and ethanol, stirring, dripping 20ml of 80% methanol solution into the solution, stirring at 80 ℃ for 1 hour, pouring out the solution, washing with deionized water, drying at 120 ℃, and roasting at 400 ℃ for 1 hour to obtain a semi-finished catalyst P;
(5) Dissolving 0.16g of silver nitrate into 47g of ionized water to obtain an impregnating solution containing Ag, immersing a semi-finished catalyst P into the prepared impregnating solution containing Ag, standing for 4 hours after the solution is fully absorbed, dripping 5ml of hydrazine hydrate solution with the concentration of 5% into the solution, stirring for 1 hour at room temperature, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.
The catalyst prepared in example 4 had a Pd content of 0.0357% and an Ag content of 0.12% as measured by atomic absorption spectrometry.
Comparative example 4
This comparative example provides a catalyst in which the catalyst support and the preparation conditions are the same as in example 4, except that the calcination temperature in step (4) is 230 ℃.
And (3) preparing a catalyst:
(1) Weighing 60.88g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 190 ℃ for 2 hours to obtain a semi-finished catalyst M1;
(2) Mixing 17.8mg of tris (4-formylphenyl) amine with 0.0059mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst M, stirring, dropwise adding a mixed solution of 14.59mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 180 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst N1;
(3) Dissolving 74.31mg of palladium acetate in 50ml of chloroform, and keeping until the palladium acetate is completely dissolved for later use;
(4) Immersing a semi-finished catalyst N1 in 50ml of 30% ethanol solution, dripping the solution prepared in the step (3) into a mixture of the semi-finished catalyst N1 and ethanol, stirring at the same time, dripping 20ml of 80% methanol solution into the solution, stirring at 80 ℃ for 1 hour, pouring out the solution, washing with deionized water, drying at 120 ℃, and roasting at 230 ℃ for 1 hour to obtain a semi-finished catalyst P1;
(5) Dissolving 0.16g of silver nitrate into 47g of ionized water to obtain an impregnating solution containing Ag, immersing a semi-finished catalyst P1 into the prepared impregnating solution containing Ag, standing for 4 hours after the solution is fully absorbed, dripping 5ml of 5% hydrazine hydrate solution into the solution, stirring for 1 hour at room temperature, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.
The catalyst prepared in comparative example 4 had a Pd content of 0.035% and an Ag content of 0.12% as measured by atomic absorption spectrometry.
Example 5
The present embodiment provides a catalyst wherein:
and (3) a carrier: spherical alumina-magnesia carrier is adopted, the magnesia content is 10 percent, and the diameter is 2mm. After being roasted for 4 hours at 1080 ℃, the pore volume is 0.55m 3 Per gram, specific surface area of 35.36m 2 And/g. 100g of the carrier was weighed.
And (3) preparing a catalyst:
(1) Weighing 56.52g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 190 ℃ for 2 hours to obtain a semi-finished catalyst Q;
(2) Mixing 8.59mg of tris (4-formylphenyl) amine with 0.0027mg of dichloroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst Q, stirring, dropwise adding a mixed solution of 7.50mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 190 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst R;
(3) Dissolving 71.57mg of palladium acetylacetonate in 50ml of benzene, and keeping until palladium acetylacetonate is completely dissolved for later use;
(4) Immersing a semi-finished catalyst R in 50ml of 80% methanol solution, dripping the solution prepared in the step (3) into a mixture of the semi-finished catalyst R and methanol, stirring at the same time, dripping 10ml of 50% formic acid solution into the solution, stirring at 50 ℃ for 1 hour, pouring the solution, washing with deionized water, drying at 120 ℃, and roasting at 380 ℃ for 1 hour to obtain a semi-finished catalyst S;
(5) Dissolving 0.095g of silver nitrate into 52.25g of deionized water to obtain an impregnating solution containing Ag, immersing a semi-finished catalyst S into the prepared impregnating solution containing Ag, standing for 4 hours after the solution is fully absorbed, dripping 20ml of a formic acid solution with concentration of about 50% into the solution, stirring for 1 hour at 50 ℃, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.
The catalyst prepared in example 5 had a Pd content of 0.025% and an Ag content of 0.06% as measured by atomic absorption spectrometry.
Comparative example 5
This comparative example provides a catalyst in which the catalyst support was the same as in example 5 except that tris (4-formylphenyl) amine was used in step (2) at a factor of 2 as compared to example 5.
(1) Weighing 56.52g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 190 ℃ for 2 hours to obtain a semi-finished catalyst Q1;
(2) Mixing 8.59mg of tris (4-formylphenyl) amine with 0.0027mg of dichloroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst Q, stirring, dropwise adding a mixed solution of 7.50mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 190 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst R1;
(3) Dissolving 71.57mg of palladium acetylacetonate in 50ml of benzene, and keeping until palladium acetylacetonate is completely dissolved for later use;
(4) Immersing a semi-finished catalyst R1 in 50ml of 80% methanol solution, dripping the solution prepared in the step (3) into a mixture of the semi-finished catalyst R1 and methanol, stirring at the same time, dripping 10ml of 50% formic acid solution into the solution, stirring at 50 ℃ for 1 hour, pouring out the solution, washing with deionized water, drying at 120 ℃, and roasting at 380 ℃ for 1 hour to obtain a semi-finished catalyst S1;
(5) Dissolving 0.095g of silver nitrate into 52.25g of deionized water to obtain an impregnating solution containing Ag, immersing a semi-finished catalyst S1 into the prepared impregnating solution containing Ag, standing for 4 hours after the solution is fully absorbed, dripping 20ml of a formic acid solution with the concentration of about 50% into the solution, stirring for 1 hour at 50 ℃, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.
The catalyst prepared in comparative example 5 had a Pd content of 0.025% and an Ag content of 0.06% as measured by atomic absorption spectrometry.
Example 6
The present embodiment provides a catalyst wherein:
and (3) a carrier: the commercial spherical carrier is adopted, the alumina content is 97 percent, the titanium oxide content is 3 percent, and the diameter is 3mm. Roasting at 1060 deg.c for 4 hr to obtain pore volume of 0.52m 3 Per gram, specific surface area of 38.75m 2 And/g. 100g of the carrier was weighed.
And (3) preparing a catalyst:
(1) Weighing 56.44g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 190 ℃ for 1 hour to obtain a semi-finished catalyst U;
(2) Mixing 7mg of tris (4-formylphenyl) amine with 0.0035mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst U, stirring and dropwise adding a mixed solution of 4.59mg of biphenyldiamine and 10ml of chloroethane, standing the mixture at room temperature for 100 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst V;
(3) 70mg of palladium acetate is dissolved in 50ml of dichloroethane, and the palladium acetate is completely dissolved for standby;
(4) Immersing a semi-finished catalyst V in 50ml of 30% ethanol solution, dripping the solution prepared in the step (3) into a mixture of the semi-finished catalyst V and ethanol, stirring at the same time, dripping 30ml of 50% acetaldehyde solution into the solution, stirring at 60 ℃ for 1 hour, pouring the solution, washing with deionized water, drying at 120 ℃, and roasting at 370 ℃ for 2 hours to obtain a catalyst W;
(5) Weighing 0.135g of silver nitrate, dissolving the silver nitrate into 54.46g of deionized water to obtain an impregnating solution containing Ag, immersing a semi-finished catalyst W into the prepared impregnating solution containing Ag, standing for 4 hours after the solution is fully absorbed, dripping 50ml of an acetaldehyde solution with concentration of more than 50%, stirring for 1 hour at 60 ℃, pouring the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.
The catalyst prepared in example 6 had a Pd content of 0.0336% and an Ag content of 0.085% as measured by atomic absorption spectrometry.
Comparative example 6
This comparative example provides a catalyst wherein:
and (3) a carrier: the catalyst was prepared using the same support as in example 6, using tris (4-formylphenyl) amine and phenylenediamine.
And (3) preparing a catalyst:
(1) Weighing 56.44g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 190 ℃ for 1 hour to obtain a semi-finished catalyst U1;
(2) Mixing 7mg of tris (4-formylphenyl) amine with 0.0035mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst U, stirring and dropwise adding a mixed solution of 4.59mg of phenylenediamine and 10ml of chloroethane, standing the mixture at room temperature for 100 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst V1;
(3) Dissolving 70.06mg of palladium acetate in 50ml of chloroform until the palladium acetate is completely dissolved for later use;
(4) Immersing a semi-finished catalyst V1 in 50ml of 30% ethanol solution, dripping the solution prepared in the step (3) into a mixture of the semi-finished catalyst V1 and ethanol, stirring at the same time, dripping 30ml of 50% acetaldehyde solution into the solution, stirring at 60 ℃ for 1 hour, pouring out the solution, washing with deionized water, drying at 120 ℃, and roasting at 370 ℃ for 2 hours to obtain a semi-finished catalyst W1;
(5) Weighing 0.135g of silver nitrate, dissolving the silver nitrate into 54.46g of deionized water to obtain an impregnating solution containing Ag, immersing a semi-finished catalyst W1 into the prepared impregnating solution containing Ag, standing for 4 hours after the solution is fully absorbed, dripping 50ml of an acetaldehyde solution with concentration of more than 50%, stirring for 1 hour at 60 ℃, pouring the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.
The catalyst prepared in comparative example 6 had a Pd content of 0.033% and an Ag content of 0.085% as measured by atomic absorption spectrometry.
Example 7
The present embodiment provides a catalyst wherein:
and (3) a carrier: a commercially available spherical alumina carrier was used, 3mm in diameter. Roasting for 4 hours at 1150 ℃ and then obtaining the pore volume of 0.65m 3 Per gram, specific surface area of 15.17m 2 And/g. 100g of the carrier was weighed.
And (3) preparing a catalyst:
(1) Weighing 74.66g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 210 ℃ for 2 hours to obtain a semi-finished catalyst X;
(2) Mixing 27.27mg of tris (4-formylphenyl) amine with 0.010mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst X, stirring and dropwise adding a mixed solution of 32.11mg of 2-chlorobiphenyl diamine and 10ml of dichloroethane, standing the mixture at room temperature for 120 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst Y;
(3) Weighing 0.086g of palladium acetylacetonate, dissolving in 50ml of dichloroethane, and keeping until palladium acetylacetonate is completely dissolved for later use;
(4) Immersing a semi-finished catalyst Y in 50ml of 30% ethanol solution, dropwise adding the solution prepared in the step (3) into a mixture of the semi-finished catalyst Y and methanol, stirring at the same time, dropwise adding 3ml of 5% hydrazine hydrate solution into the solution, stirring at room temperature for 1 hour, pouring out the solution, washing with deionized water, drying at 120 ℃, and roasting at 300 ℃ for 2 hours to obtain a semi-finished catalyst Z;
(5) Weighing 0.21g of silver nitrate, dissolving the silver nitrate into 67.60g of deionized water to obtain an impregnating solution containing Ag, immersing a semi-finished catalyst Z into the prepared impregnating solution containing Ag, standing for 4 hours after the solution is fully absorbed, dripping 3ml of a 5% hydrazine hydrate solution into the solution, stirring for 1 hour at room temperature, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.
The catalyst prepared in example 7 had a Pd content of 0.03% and an Ag content of 0.13% as measured by atomic absorption spectrometry.
Comparative example 7
This comparative example provides a catalyst wherein:
and (3) a carrier: the same carrier as in example 7 was used.
And (3) preparing a catalyst: the preparation conditions were the same as in example 7, except that the amount of silver nitrate used in step (5) was 2 times that used in example 7.
(1) Weighing 74.66g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 210 ℃ for 2 hours to obtain a semi-finished catalyst X1;
(2) Mixing 27.27mg of tris (4-formylphenyl) amine with 0.010mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst X, stirring and dropwise adding a mixed solution of 32.11mg of 2-chlorobiphenyl diamine and 10ml of dichloroethane, standing the mixture at room temperature for 120 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst Y1;
(3) 0.086g of palladium acetylacetonate is weighed and dissolved in 50ml of dichloroethane, and the palladium acetylacetonate is completely dissolved for standby.
(4) Immersing the semi-finished catalyst Y1 in 50ml of 30% ethanol solution, dripping the solution prepared in the step (3) into a mixture of the semi-finished catalyst Y1 and methanol, stirring at the same time, dripping 3ml of hydrazine hydrate solution with the concentration of 5% into the solution, stirring at room temperature for 1 hour, pouring out the solution, washing with deionized water, drying at 120 ℃, and roasting at 300 ℃ for 2 hours to obtain the semi-finished catalyst Z1.
(5) Weighing 0.42g of silver nitrate, dissolving the silver nitrate into 67.60g of deionized water to obtain an impregnating solution containing Ag, immersing a semi-finished catalyst Z1 into the prepared impregnating solution containing Ag, standing for 4 hours after the solution is fully absorbed, dripping 3ml of a 5% hydrazine hydrate solution into the solution, stirring for 1 hour at room temperature, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.
The catalyst prepared in comparative example 7 had a Pd content of 0.03% and an Ag content of 0.42% as measured by atomic absorption spectrometry.
Performance of catalyst for hydrogenation reaction after two carbon atoms
Evaluation mode: the catalyst loading in the fixed bed reactor was 100mL (recording weight), packing 50mL, space velocity of reaction mass: 4000/h, operating pressure 2.5MPa, hydrogen-alkyne ratio 1.4, reactor inlet temperature 55 ℃.
The evaluation results were calculated as shown in Table 1.
Table 1 evaluation results calculation method
The initial selectivity was the selectivity measured 24 hours from the start of the reactor charge.
The initial activity was the activity (acetylene conversion) measured 24 hours from the start of the reactor charge.
The reaction mass composition was as follows:
acetylene 0.9% (mol/mol), ethylene 82% (mol/mol), ethane 17% (mol/mol), and carbon three 0.5% (mol/mol).
The evaluation results of the catalyst are shown in Table 2.
Table 2 results of catalyst evaluation
The comparison of the results of the catalyst evaluations in Table 2 can be seen:
in comparison with example 1, since the inner pores are free of polymer, the active component is distributed in all spaces of the pores, and is affected by the diffusion limitation of the gas phase reaction, and the acetylene conversion and selectivity are not ideal.
In comparative example 2, since the temperature is high in the constant temperature stage of step (1), part of lactic acid is polymerized and part of lactic acid is decomposed, but not completely decomposed, so that most of the organic cage is synthesized outside the carrier, and a small part of palladium is supported inside the carrier, and although clusters having hydrogenation activity are formed during the calcination, the activity selectivity is poor because part of the active center is in the inner hole of the catalyst.
In comparative example 3, since the conventional catalyst preparation method is adopted, the size distribution of the active center is wide, the size of part of the active center is larger than 3nm, and part of the active center is smaller, so that the activity, particularly the selectivity, is obviously lower than that of the example, the generation amount of carbon four is far higher than that of the example 3, and the catalyst is seriously coked after 1000 hours.
In comparative example 4, the calcination temperature in step (4) was low, polylactic acid was not completely decomposed, and the catalyst channels were blocked, so that the reaction mass was not diffused through the channels, and thus the activity was low.
In comparative example 5, the amount of tris (4-formylphenyl) amine was increased to increase the number of organic cages formed, the number of corresponding active centers was excessive, the size of palladium active center supported by a single organic cage was decreased, and the activity was insufficient. And the activation rate of hydrogen is reduced due to too small active center, hydrogen is insufficient in hydrogenation reaction, more carbon four is generated, and the performance of the catalyst decays rapidly.
In comparative example 6, the second monomer was phenylenediamine, and the size of the synthesized organic cage was smaller than the optimal active center stacking size required for acetylene hydrogenation, so the initial activity was lower; part of palladium cannot enter the organic cage, can be only distributed on the carrier in a very dispersed way, and does not contribute to the catalytic reaction.
In comparative example 7, silver was excessively supported, part of the original active sites were covered, acetylene could not be effectively adsorbed on the catalyst surface, and the catalyst activity was markedly insufficient from the beginning although the initial selectivity was good.
The catalyst has the advantages that the size distribution of the active center is narrow and is in a range with better activity, so that active components are fully utilized, and the loading amount of noble metals is reduced; on the other hand, as the excessive active center is reduced, the coupling probability of vinyl which is an intermediate of acetylene hydrogenation reaction is reduced, and the yield of green oil is obviously reduced. The catalyst running period is obviously prolonged.

Claims (12)

1. An alkyne selective hydrogenation catalyst, wherein the carrier of the catalyst is alumina or mainly alumina;
the active component of the catalyst contains Pd and Ag, the content of Pd is 0.02-0.04%, the content of Ag is 0.03-0.15%, and the content of Ag is preferably 0.05-0.15% based on 100% of the mass of the carrier;
the catalyst is provided with an organic cage, the distance between the organic cage and the outer surface of the catalyst is within 0.2mm, the size of the organic cage is 1.9-2.7nm, and Pd is loaded in the organic cage.
2. The catalyst according to claim 1, wherein the specific surface area of the catalyst is 15-40m 2 /g。
3. The catalyst of claim 1 or 2, wherein the alumina in the support is in the form of theta, alpha or a mixture thereof; alumina in the catalyst carrier is more than 80%;
preferably, the support also contains other metal oxides, more preferably titanium oxide and/or magnesium oxide.
4. A process for the preparation of a catalyst as claimed in any one of claims 1 to 3 comprising the steps of:
(1) Mixing a hydrophilic polymerizable monomer with a roasted carrier, and polymerizing at a certain temperature to obtain a first semi-finished catalyst, wherein the volume of a polymer synthesized by the hydrophilic polymerizable monomer is 80-95% of the pore volume of the carrier;
(2) Mixing tri (4-formylphenyl) amine and halogenated acetic acid, dissolving in halogenated acetic acid, then mixing with a first semi-finished catalyst, stirring and dropwise adding a mixed solution of a phenyl diamine substituent and halogenated acetic acid, standing the mixture, pouring out residual liquid after the reaction is completed, washing with alcohol and deionized water respectively, and drying to obtain a second semi-finished catalyst;
wherein the molar ratio of the phenyl diamine or the substituent thereof to the tri (4-formylphenyl) amine is 1.2-2:1, the mass ratio of the tri (4-formylphenyl) amine to the halogenated acetic acid is 2000-6000:1;
(3) Dissolving an organic palladium compound in an organic solvent to obtain a palladium precursor solution, wherein the mass ratio of the palladium in the organic palladium compound to the tris (4-formylphenyl) amine is 0.63-4.8:1;
(4) Immersing the second semi-finished catalyst into an alcohol solution, dropwise adding a palladium precursor solution into a mixture of the second semi-finished catalyst and alcohol, stirring at the same time, dropwise adding a reducing agent, heating and stirring until the surface of the second semi-finished catalyst is not discolored, pouring out the solution, washing with deionized water, drying, and roasting at a temperature at which the polymer formed in the step (1) can be decomposed to obtain a third semi-finished catalyst;
(5) Dissolving soluble silver salt in deionized water or an organic solvent to obtain a silver impregnation solution, immersing a third semi-finished catalyst in the silver impregnation solution, and standing after the third semi-finished catalyst is fully absorbed;
and (3) dropwise adding a reducing agent to reduce silver, pouring the solution, washing with deionized water, and drying to obtain the catalyst, or, without reduction, pouring the solution, washing with deionized water, drying, and roasting to obtain the catalyst.
5. The production method according to claim 4, wherein in the step (1), the hydrophilic polymerizable monomer is a monomer containing a carbonyl group and/or a carboxyl group and capable of undergoing polymerization or condensation reaction, preferably comprising acrylic acid, lactic acid or formaldehyde.
6. The production process according to claim 4, wherein in step (2), the phenylenediamine is a biphenyldiamine or a substituent thereof, preferably a p-biphenyldiamine or a substituent thereof, and the substituent of the substituent is preferably a halogen or an alkyl group.
7. The production process according to claim 4, wherein in step (2), the halogenated acetic acid comprises a fluorinated acetic acid or a chloroacetic acid, preferably a trifluoroacetic acid or a dichloroacetic acid.
8. The process according to claim 4, wherein in step (2), the haloalkane comprises a fluoroalkyl, chloroalkane or bromoalkane, preferably a halomethane or a haloethane, more preferably dichloroethane or trichloromethane.
9. The production method according to claim 4, wherein in the step (3), the organic palladium compound comprises one or a combination of two or more of palladium acetate, palladium lactate and palladium acetylacetonate.
10. The production method according to claim 4, wherein in step (4), the alcohol comprises ethanol or methanol.
11. The process according to claim 4, wherein in the step (4) and the step (5), the reducing agent is a reducing compound, preferably one or a combination of two or more of methanol, formaldehyde, formic acid, ethanol, acetaldehyde, and hydrazine hydrate.
12. The preparation method according to claim 4, wherein in step (5), the soluble silver salt is a silver salt soluble in water or an organic solvent, preferably silver nitrate and/or silver acetylacetonate.
CN202210846584.9A 2022-07-19 2022-07-19 Alkyne selective hydrogenation catalyst and preparation method thereof Pending CN117463324A (en)

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