Hydrogenation method for C1-C3 fractions

Abstract

The invention discloses a C1-C3 fraction hydrogenation method, the C1-C3 fraction comprises the following components by volume: 10%-30% of H2, 25%-40% of C2H4, 0.4%-0.9% of C2H2, 5%-11% of C3H6, 0.2%-1.2% of PDMA, 0.04%-0.14% of CO, and the balance of methane, ethane and propane, a catalyst used in the hydrogenation method comprises a carrier, an active component and an organic cage, the carrier mass is 100%, the Pd content is 0.02%-0.04%, the organic cage mass is 0.1%-0.5%, the active component mass is 0.1%-0.5%, and the organic cage mass is 0.1%-0.5%. The content of Ag is 0.07-0.18%, the active component Pd is loaded in an organic cage, and the size of the organic cage is 2.7-3.6 nm.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogenation catalysts, and particularly relates to a method for hydrogenating C1-C3 fractions. Background Art

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

[0003] According to the relative position of the C2 hydrogenation reactor and demethanation, C2 hydrogenation is divided into pre-hydrogenation and post-hydrogenation. The C2 pre-hydrogenation reactor is before the demethanation tower, and the hydrogenation feed generally contains C1, C2 fractions and C3 fractions. In addition to hydrogen and methane in the C1 fraction, there is also CO. Generally, the feed composition of pre-hydrode-propane pre-hydrogenation is:

[0004] H 2 15% - 30%, C 2 H 6 4% - 10%, C 2 H 4 25% - 40%, C 2 H 2 0.4% - 0.7%, C 3 H 6 8% - 11%, C 3 H 8 1% - 2%, propyne 0.1% - 0.6%, allene 0.1% - 0.6%, CO 0.04% - 0.14%.

[0005] During the selective hydrogenation process, the hydrogenation dimerization reaction of acetylene easily occurs to generate C4 fractions, and the C4 fractions further polymerize to form oligomers with a wide molecular weight range, commonly known as "green oil". The green oil adsorbs on the catalyst surface and further forms coke, blocking the catalyst pores, preventing the reactants from diffusing to the surface of the catalyst active center, thereby resulting in a decrease in catalyst activity.

[0006] In traditional hydrogenation methods, the noble metal catalysts used have high activity, but green oil is easily formed during operation, causing coking deactivation of the catalysts and affecting the catalyst stability and service life. CN200810119385.8 discloses a non-noble metal supported selective hydrogenation catalyst, its preparation method and application, including a carrier and a main active component and a promoter supported on the carrier. Among them, the main active component is Ni, and the promoter is selected from at least one of Mo, La, Ag, Bi, Cu, Nd, Cs, Ce, Zn, and Zr. The main active component and the promoter both exist in an amorphous form, with an average particle size <10 nm. The carrier is a non-oxidizing porous material; and the catalyst is prepared by a microemulsion method.

[0007] CN200810114744.0 discloses an unsaturated hydrocarbon selective hydrogenation catalyst and its preparation method. This catalyst uses alumina as the carrier and palladium as the active component, and improves the anti-impurity and anti-coking performance of the catalyst by adding rare earth, alkaline earth metals, and fluorine, but the selectivity of the catalyst is not ideal.

[0008] The catalysts used in the above selective hydrogenation processes all adopt catalysts with a single pore size distribution. During the fixed-bed reaction process, affected by internal diffusion, the selectivity of the catalyst is poor. A carrier with a bimodal pore distribution can reduce the influence of internal diffusion and improve the catalyst selectivity while ensuring high catalyst activity. CN101433842A discloses a hydrogenation catalyst, characterized in that the catalyst has a bimodal pore distribution, the most probable radius of the small pore part is 2-50 nm, and the most probable radius of the large pore part is 100-500 nm. Due to the bimodal pore distribution of the catalyst, it has good hydrogenation activity and good selectivity, and a large ethylene increment.

[0009] In the C2 hydrogenation reaction, the formation of green oil and the coking of the catalyst are important factors affecting the service life of the catalyst. The activity, selectivity, and service life of the catalyst constitute the overall performance of the catalyst. The above-listed methods either propose good ways to improve the catalyst activity and selectivity, but do not solve the problem of easy coking of the catalyst, or solve the problems of easy formation of green oil and coking of the catalyst, but do not solve the selectivity problem. Although the carrier with a macroporous structure can improve the selectivity, the larger molecules generated by polymerization and chain growth reactions are also easily retained in the macropores of the carrier, causing coking deactivation of the catalyst and affecting the service life of the catalyst.

[0010] In the C2 selective hydrogenation reaction, when Pd is the main active component, during the traditional impregnation process for preparing the catalyst, Pd is in the form of Pd 2+ or [PdCl 4 2- ​Combined with the carrier in the form of ions, Pd aggregates to form active centers during the activation process. Since the aggregation of Pd during the activation process is a random process dominated by kinetics, that is, it is difficult to control the size of each active center in advance.

[0011] Previous studies have found that in the process of selective hydrogenation of acetylene, the process is as follows: First, an acetylene molecule combines with one hydrogen atom to form vinyl, and then vinyl combines with a hydrogen atom to form ethylene, or two vinyls couple to form butadiene. Since butadiene can undergo a series of polymerization reactions to form green oil and then coke, inhibiting the formation of butadiene has become the key to preventing coking of the C2 selective hydrogenation catalyst.

[0012] Obviously, if two vinyls are formed simultaneously on one catalyst active center, the probability of forming butadiene will increase significantly. Studies have also found that when the size of the active center is large, the yield of butadiene increases. Generally, there are two ways to prevent the large size of the active center: one is to reduce the amount of the active component, and the other is to expand the dispersion area of the active component. However, reducing the loading amount of the active component may result in insufficient active centers, leading to insufficient hydrogenation activity, incomplete removal of acetylene, unqualified hydrogenation products, and great economic losses.

[0013] When the dispersion area of the active component is expanded, some of the active centers are not located close to the catalyst surface, resulting in poor catalyst selectivity and large ethylene loss during the hydrogenation process.

[0014] To prepare a catalyst with better hydrogenation performance, some researchers have synthesized a series of organic cages with three-dimensional structures in recent years. In "Three-dimensional hydrophobic porous organic polymers confined Pd nanoclusters for phase-transfer catalytic hydrogenation of nitroarenes in water", it is disclosed that in this literature, tris(4-formylphenyl)amine and phenylenediamine are used to synthesize an organic three-dimensional organic cage, and the synthesized organic cage is uniformly distributed on the surface of silica. Metal palladium is loaded in the synthesized organic cage and used for the hydrogenation of nitrobenzene in the liquid phase to prepare aniline.

[0015] The catalyst preparation steps in the literature include two steps. First, tris(4-formylphenyl)amine is mixed with haloacetic acid, dissolved in a haloalkane, and then mixed with a silica support. After stirring, a mixed solution of an aromatic diamine compound and a haloalkane is added dropwise. The mixture is allowed to stand. After the reaction is complete, the residual liquid is poured out, and the product is washed with alcohol and deionized water respectively, dried to obtain silica supported with organic cages. Then, an organic palladium salt is dissolved in an organic solvent to obtain a palladium precursor. The silica supported with organic cages is immersed in an alcohol solution, and the palladium precursor solution is added dropwise to the mixture of silica and alcohol while stirring. After the addition of the palladium precursor solution is completed, the mixture is allowed to stand, the solution is poured out, dried, and calcined to obtain the desired catalyst. Although some of the sizes of the organic cages prepared in this literature are within the range of the active center sizes required for gaseous acetylene, the organic cages prepared in this literature are uniformly distributed within the support and can only be used for liquid-phase saturated hydrogenation or phase-transfer catalytic hydrogenation, but not for gas-phase selectivity. The reason is that gas-phase selective hydrogenation is a reaction limited by internal diffusion and requires the active center to be located on the outer layer of the catalyst, while the catalyst prepared in this comparative literature cannot meet this requirement.

[0016] CN202111602774.8 discloses a preparation method of a cluster Pd catalyst. In this preparation method, first, using trimellitic aldehyde and (1R,2R)-cyclohexanediamine as raw materials, an organic molecular cage is synthesized. Then, AT-RCC3 organic molecular cage is synthesized by reacting RCC3 with acetone, and FT-RCC3 organic molecular cage is synthesized by reacting RCC3 with paraformaldehyde. Then, Pd clusters are loaded by the cavity confinement effect of RCC3, AT-RCC3, and FT-RCC3 molecular cages to prepare Pd@RCC3, Pd@AT-RCC3, and Pd@FT-RCC3 catalysts with adjustable Pd cluster sizes. The sizes of the cavities of the prepared Pd@RCC3, Pd@AT-RCC3, and Pd@FT-RCC3 are 0.7, 0.67, and 0.4 nm respectively.

[0017] These organic cages have fixed sizes and can be used to immobilize metals, thereby preparing catalysts with highly dispersed metal clusters. Currently, after these three-dimensional organic cages are loaded with active components, they are either in solution or uniformly distributed on the support and are used for full hydrogenation or homogeneous hydrogenation. For selective hydrogenation, not only does the size of the active center affect the reaction, but also the distribution of the active component in the catalyst has a great impact on the reaction result. Catalysts with uniformly distributed active components are not suitable for selective hydrogenation reactions.

[0018] At present, there are many studies on noble metal single-atom catalysts in hydrogenation reactions. However, for the hydrogenation of alkynes, there is still a significant gap between such catalysts and practical applications. The reasons are as follows: At the active center of the hydrogenation reaction, two processes need to be completed. One is the activation of the alkyne molecule, that is, the electron pair of the double bond of the alkyne molecule enters the empty orbital of the active center atom, and the active center atom then feeds back the electron pair to the antibonding orbital of the alkyne molecule, resulting in a decrease in the double bond energy, activation of the double bond, and cleavage. At the same time, the hydrogen molecule also requires the same process to be activated into hydrogen atoms. For a single-atom active center, due to the limited physical size of a single atom, it is difficult to complete these two processes simultaneously, so the reaction process is relatively slow and difficult to meet the requirements of practical applications. Therefore, it is natural that the active center needs to have a certain physical size. In fact, for palladium catalysts, since a large amount of hydrogen can be absorbed inside their stacking structure, the activation of hydrogen and the transfer of hydrogen atoms are completed within the palladium stacking structure, so their activity is higher than that of active components that can only adsorb hydrogen on the surface. Summary of the Invention

[0019] The object of the present invention is to provide a method for hydrogenating C1-C3 fractions, which can improve the operation cycle of the hydrogenation reaction and reduce costs.

[0020] To achieve the above object, the present invention provides a method for hydrogenating C1-C3 fractions. The C1-C3 fractions contain, by volume, H 2 10% - 30%, C 2 H 4 25% - 40%, C 2 H 2 0.4% - 0.9%, C 3 H 6 5% - 11%, PDMA (propyne allene) 0.2% - 1.2%, CO 0.04% - 0.14%, and the rest are methane, ethane, and propane. The catalyst used in the hydrogenation method includes a carrier, an active component, and an organic cage. The active component contains Pd and Ag. Based on the mass of the carrier being 100%, the content of Pd is 0.02 - 0.04%, and the content of Ag is 0.07 - 0.18%. The active component Pd is loaded inside the organic cage, and the size of the organic cage is 2.7 - 3.6 nm.

[0021] The hydrogenation method for C1-C3 fractions of the present invention, the active component further contains Cu, and based on the mass of the carrier being 100%, the content of Cu is 1-5%. In the pre-hydrogenation reaction of C2, in addition to the hydrogenation dimerization of acetylene to produce by-product butadiene, the hydroacylation reaction will occur between CO and olefins to produce by-products such as propionaldehyde. The adsorption capacity of these by-products on the surface of alumina is stronger, and it is more likely to cause catalyst deactivation. The role of Cu is to hydrogenate such carbonyl compounds to produce alcohols, etc., to avoid the condensation of these carbonyl groups to form larger molecules.

[0022] The hydrogenation method for C1-C3 fractions of the present invention, the specific surface area of the catalyst is 1-15 m 2 / g.

[0023] The hydrogenation method for C1-C3 fractions of the present invention, in the preparation process of the catalyst, an organic cage is first synthesized in the carrier and then Pd is loaded.

[0024] The hydrogenation method for C1-C3 fractions of the present invention, in the preparation process of the catalyst, Ag is loaded before the synthesis of the organic cage.

[0025] The hydrogenation method for C1-C3 fractions of the present invention, Cu is loaded simultaneously with Ag before the loading of Pd, or is loaded alone after the loading of Pd.

[0026] The method for hydrogenating C1-C3 fractions in the present invention involves adding a reducing agent after loading Pd or loading Cu alone, and performing liquid-phase reduction. The reducing agent is one or more of hydrazine hydrate, formic acid, formaldehyde, methanol, ethanol, acetaldehyde, etc. Specifically, the product after loading Pd is impregnated in an aqueous solution containing a copper salt. After the solution is completely absorbed, it is left standing for a period of time, then a reducing agent is added, and stirred for a period of time, and then at least through a drying step, a selective hydrogenation catalyst is obtained. The reducing agents used include but are not limited to: a combination of one or more of hydrazine hydrate, formic acid, formaldehyde, methanol, ethanol, acetaldehyde, etc. The reducing agent can be added in the form of an aqueous solution of the reducing agent, and the mass concentration of the aqueous solution of the reducing agent can be conventionally adjusted by those skilled in the art, for example, 5-50%. More preferably, the reducing agent includes a combination of one or more of hydrazine hydrate, formic acid, formaldehyde, etc. The ratio of the reducing agent to the copper salt can be conventionally adjusted by those skilled in the art, and generally an excessive amount of the reducing agent is used. The present invention preferably adopts this loading method of adding a reducing agent, that is, the liquid-phase in-situ reduction method. The reducing agent can reduce copper to copper atoms, which is beneficial to improving the activity of copper. Among them, more preferably, the temperature for stirring after adding the reducing agent is from room temperature to 60 °C, and the time is 10-200 minutes. In the method for hydrogenating C1-C3 fractions in the present invention, the preparation method of the organic cage is as follows: Ag is loaded on a carrier to obtain a semi-finished catalyst, a hydrophilic polymerizable monomer is mixed with the semi-finished catalyst after loading Ag, and the polymerizable monomer is polymerized to obtain a semi-finished catalyst containing a polymer; tris(4-formylphenyl)amine and haloacetic acid are mixed, dissolved in a haloalkane, and then mixed with the semi-finished catalyst containing a polymer, and a mixed solution of 4,4”-diaminoterphenyl and a haloalkane is added dropwise, left standing, and after the reaction is complete, the residual liquid is poured out, washed, and dried to obtain a semi-finished catalyst containing an organic cage.

[0027] In the method for hydrogenating C1-C3 fractions in the present invention, the volume of the polymer is 70-95% of the pore volume of the carrier, preferably 75-95%.

[0028] In the method for hydrogenating C1-C3 fractions in the present invention, the hydrophilic polymerizable monomer is acrylic acid and / or lactic acid.

[0029] In the method for hydrogenating C1-C3 fractions in the present invention, the 4,4”-diaminoterphenyl is substituted or unsubstituted 4,4”-diaminoterphenyl, and the substituent is a halogen or an alkyl group.

[0030] In the method for hydrogenating C1-C3 fractions in the present invention, the molar ratio of 4,4”-diaminoterphenyl to tris(4-formylphenyl)amine is 1.3-2.0:1, and the mass ratio of tris(4-formylphenyl)amine to haloacetic acid is 1000-3000:1.

[0031] The method for hydrogenating C1-C3 fractions according to the present invention, the method for loading Pd is as follows: adding an organic palladium salt into an organic solvent to obtain a palladium precursor solution, immersing a carrier containing an organic cage into an alcohol solution, dropping the palladium precursor solution into a mixture of the carrier containing the organic cage and the alcohol solution while stirring, standing still after dropping, pouring off the solution, washing, drying, calcining or performing liquid-phase reduction to obtain a Pd-loaded catalyst.

[0032] The method for hydrogenating C1-C3 fractions according to the present invention, the mass ratio of palladium in the organic palladium salt to the mass of tris(4-formylphenyl)amine is 1.5-10:1.

[0033] The method for hydrogenating C1-C3 fractions according to the present invention, the calcination temperature is higher than the polymer decomposition temperature and lower than or equal to 450°C, preferably lower than or equal to 430°C.

[0034] The method for hydrogenating C1-C3 fractions according to the present invention, Ag and Cu are loaded in an impregnation manner. The impregnation loading method described in the present invention is a commonly used loading method in the art. Specifically, a soluble active component precursor is dissolved in deionized water to form an impregnation solution containing an active metal, and then the calcined carrier is impregnated in the impregnation solution. After complete absorption, it is left standing, dried, and calcined to complete the loading. In the present invention, Ag is loaded before Pd. Cu can be loaded simultaneously with Ag before Pd loading, or can be loaded separately after Pd loading.

[0035] The method for hydrogenating C1-C3 fractions according to the present invention, the hydrogenation reaction space velocity is 8000-22000 / h, the reaction pressure is 3.0-4.0 MPa, and the reactor inlet temperature is 65-100°C.

[0036] Advantages of the present invention:

[0037] The hydrogenation method of the present invention is applied to the selective hydrogenation of C1-C3 fractions in an ethylene plant. To improve the operation cycle of the hydrogenation reaction and reduce costs, in the hydrogenation method of the present invention, the active component palladium is located in an organic cage with a fixed size, and its maximum size is the size of the cage. The size distribution of the active centers is narrow, reducing the active centers with an aggregated size greater than 4.0 nm. The probability of simultaneously forming 2 vinyl groups or the simultaneous adsorption of CO and olefins at one active center is greatly reduced, reducing the probability of the hydroformylation reaction, that is, reducing the generation of by-products, delaying the catalyst deactivation rate, the yield of butene can be reduced to less than 1 / 2 of that of traditional catalysts, extending the reaction operation time, and also avoiding the problem of insufficient activity due to too small active centers, reducing the waste of precious metals.

[0038] After running for a period of time, the coke on the catalyst surface can be treated by air burning. Since the organic cage is a heat-resistant structural material, it can withstand a high temperature of 450°C for a long time during the catalyst burning process. The active centers are confined in the organic cage and will not aggregate during the burning process. Therefore, the pre-hydrogenation catalyst can be burned at least once, that is, the catalyst life is extended by at least one time.

[0039] In the material of pre-decoking pre-hydrogenation, the CO content can reach up to 0.14%. The hydroacylation reaction cannot be ignored. The catalyst of the present invention has Cu active centers, which can hydrogenate the hydroacylation reaction products and delay the attenuation of the catalyst performance. Since the scale of the catalyst active centers is narrow, at a lower temperature, most of the active centers already have activity, which can reduce the initial temperature of the reactor and correspondingly expand the temperature window, making the hydrogenation process safer. Description of the Drawings

[0040] Figure 1 PET test results of the organic cage synthesized in Example 1. Detailed Embodiments

[0041] The present invention will be specifically described below through examples. It is necessary to point out here that the following examples are only used to further illustrate the present invention and should not be construed as limiting the protection scope of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention according to the above content of the present invention.

[0042] Evaluation and Analysis Method:

[0043] Analysis and Testing Method:

[0044] Specific surface area: GB / T - 5816;

[0045] Pore volume: GB / T - 5816;

[0046] Content of active components in the catalyst: Atomic absorption method;

[0047] The conversion rate and selectivity in the examples are calculated according to the following formulas:

[0048] Acetylene conversion rate (%) = 100×△acetylene / acetylene content at the inlet

[0049] Ethylene selectivity (%) = 100×△ethylene / △acetylene

[0050] The following characterization methods were used in the preparation of the catalyst of the present invention: a BET analyzer, manufactured by Micromeritics in the United States, for measuring specific surface area and pore size distribution; an A240FS atomic absorption spectrometer for measuring the contents of Pd, Ag, and Cu in the catalyst; and an Agilent 7890A gas chromatograph for measuring the contents of hydrogen, acetylene, and butene at the reactor outlet and inlet.

[0051] A 0.1 mg electronic balance was used to measure the weight of the catalyst.

[0052] Raw materials: tris(4-formylphenyl)amine, trifluoroacetic acid, dichloroacetic acid, dichloroethane, 4,4”-diaminoterphenyl, 2-chloroterphenyl diamine, 3-methylterphenyl diamine, hydrazine hydrate, ethanol, methanol, formic acid, formaldehyde, lactic acid, acrylic acid, palladium acetate, palladium acetylacetonate, silver nitrate, copper nitrate, analytical grade, from Shanghai National Pharmaceutical Group Corporation; alumina, from Shandong Aluminum Industry Group Corporation.

[0053] Example 1

[0054] This example provides a hydrogenation method with the following hydrogenation conditions: a space velocity of 20000 / h, a single-stage isothermal reaction process, and a reaction pressure of 3.0 MPa. The reactor inlet temperature was 80 °C for 24 hours, 90 °C after 500 hours, and 100 °C after 1500 hours. The preparation process and conditions of the catalyst are as follows:

[0055] Catalyst support: Commercially available spherical alumina with a diameter of 4 mm was used. After calcination at 1270 °C for 4 h, the water absorption rate was 40%, and the specific surface area was 5 m 2 / g. 100 g of this support was weighed.

[0056] Catalyst preparation:

[0057] (1) 0.286 g of silver nitrate was dissolved in 40 ml of deionized water to obtain an aqueous solution containing silver. The calcined support was impregnated in the prepared solution. After the solution was completely absorbed, it was dried at 120 °C and calcined at 550 °C for 4 hours to obtain semi-finished catalyst A;

[0058] (2) 29.15 g of an aqueous acrylic acid solution containing 30% water, 0.012 g of potassium hypophosphite monohydrate, 0.015 g of copper acetate monohydrate, and 0.10 ml of 30% hydrogen peroxide as an initiator were mixed evenly to obtain a mixed solution containing acrylic acid. The semi-finished catalyst A was impregnated in the prepared mixed solution. After the solution was completely absorbed, it was transferred to a reflux flask and heated to 80 °C with stirring and kept at a constant temperature for 1.5 hours to obtain semi-finished catalyst B, and the polyacrylic acid accounted for 75% of the pore volume of the support;

[0059] (3) Weigh 8.44 mg of tris(4-formylphenyl)amine and 0.0084 mg of trichloroacetic acid, mix them, dissolve in 50 ml of dichloroethane, then mix with semi-finished catalyst B, stir and dropwise add a mixed solution of 11.12 mg of 4,4”-diaminoterphenyl and 10 ml of trichloroethane. Let the mixture stand at room temperature for 220 hours, pour out the residual liquid, wash with ethanol and deionized water respectively, and dry to obtain semi-finished catalyst C;

[0060] (4) Dissolve 84.39 mg of palladium acetate in 40 ml of chloroform. Wait until the palladium acetate is completely dissolved to obtain a palladium acetate solution. Immerse semi-finished catalyst C in 40 ml of ethanol solution. Drop the palladium acetate solution into the mixture of the support and ethanol while stirring. After all the solution is added, let it stand for 6 hours. Pour out the residual liquid, wash with deionized water, dry at 120 °C, and calcine at 420 °C for 2 hours to obtain the desired catalyst.

[0061] The prepared catalyst was measured by atomic absorption spectrometry. In Example 1, the Pd content was 0.04% and the Ag content was 0.18%.

[0062] The pore size results of the organic cage synthesized in Example 1 measured by the BET method are as Figure 1 shown. From Figure 1 it can be seen that the maximum pore size is 3.41 nm and the minimum pore size is 2.86 nm.

[0063] Catalyst reduction: hydrogen / nitrogen = 1:1, keep at a constant temperature of 120 °C for 4 hours, gas hourly space velocity: 200 / h.

[0064] Comparative Example 1 This comparative example provides a hydrogenation method. The hydrogenation conditions are: space velocity 20000 / h, the reaction process is single-stage isothermal, and the reaction pressure is 3.0 MPa. The reactor inlet temperature is 80 °C for 24 hours, 90 °C after 500 hours, and 100 °C after 1500 hours.

[0065] Among them, the preparation process of the catalyst used is the same as that in Example 1, except that in Comparative Example 1, the amount of tris(4-formylphenyl)amine used is 6 times that in Example 1;

[0066] The preparation process of the catalyst in Comparative Example 1 is as follows:

[0067] Support: Use the support used in Example 1.

[0068] Catalyst preparation:

[0069] (1) Dissolve 0.286 g of silver nitrate in 40 ml of deionized water to obtain an aqueous solution containing silver. Immerse the calcined support in the prepared solution. After all the solution is absorbed, dry at 120 and calcine at 550 °C for 4 hours to obtain semi-finished catalyst A;

[0070] (2) Take 29.15 g of an aqueous acrylic acid solution containing 30% water, 0.012 g of potassium hypophosphite monohydrate, 0.015 g of copper acetate monohydrate, and 0.10 ml of 30% hydrogen peroxide as initiators. After mixing evenly, a mixed solution containing acrylic acid is obtained. Immerse the semi-finished catalyst A in the prepared mixed solution. After all the solution is absorbed, transfer it to a reflux flask, heat it to 80 °C with stirring, and keep it at a constant temperature for 1.5 hours to obtain the semi-finished catalyst B, where polyacrylic acid accounts for 75% of the pore volume of the carrier;

[0071] (3) Weigh 50.64 mg of tris(4-formylphenyl)amine and mix it with 0.0084 mg of trichloroacetic acid, dissolve them in 50 ml of dichloroethane, then mix it with the semi-finished catalyst B, stir and dropwise add a mixed solution of 11.12 mg of 4,4”-diaminoterphenyl and 10 ml of trichloroethane. Let the mixture stand at room temperature for 220 hours, pour out the residual liquid, wash it with ethanol and deionized water respectively, and dry it to obtain the semi-finished catalyst C;

[0072] (4) Dissolve 84.39 mg of palladium acetate in 40 ml of chloroform. After the palladium acetate is completely dissolved, a palladium acetate solution is obtained. Immerse the semi-finished catalyst C in a 40 ml ethanol solution, and drop the palladium acetate solution into the mixture of the carrier and ethanol while stirring. After all the solution is added, let it stand for 6 hours. Pour out the residual liquid, wash it with deionized water, dry it at 120 °C, and calcine it at 420 °C for 2 hours to obtain the required catalyst.

[0073] By atomic absorption spectrometry, in the catalyst prepared in Comparative Example 1, based on 100% of the mass of the carrier, the Pd content is 0.04% and the Ag content is 0.18%.

[0074] For the synthetic organic cage in the comparative example measured by the BET method, the maximum pore diameter is 1.3 nm and the minimum pore diameter is 0.69 nm.

[0075] Catalyst reduction: hydrogen / nitrogen = 1:1, keep it at a constant temperature of 120 °C for 4 hours, gas hourly space velocity: 200 / h.

[0076] Table 1 Composition of hydrogenation materials

[0077] Component <![CDATA[H 2 > <![CDATA[C 2 H 4 > <![CDATA[C 2 H 2 > <![CDATA[C 3 H 6 > Methylacetylene and Propadiene CO Volume Content, % 10 25 0.9 6 0.3 0.05

[0078] Table 2 Hydrogenation results of Example 1 and Comparative Example 1

[0079]

[0080] As can be seen from Table 2, at an inlet temperature of 80 °C, the acetylene conversion rate in Example 1 has reached 100%, while the acetylene conversion rate in Comparative Example 1 is only 46.25%. This shows that there are obvious differences in their activities; the selectivity of the comparative example is slightly higher than that of Example 1.

[0081] After 500 hours, when the reactor inlet temperature was increased to 90 °C, the acetylene conversion rate in the example was 100%, the ethylene selectivity was 73.25%, the acetylene conversion rate in Comparative Example 1 was 65.49%, and the ethylene selectivity was 76.34%. Its activity was still significantly insufficient.

[0082] When the reactor inlet temperature was increased to 100 °C, the acetylene conversion rate in the example was 100%, and the ethylene selectivity was 71.35%, which decreased slightly compared with 95 °C. The acetylene conversion rate in Comparative Example 1 was 78.64%, and the ethylene selectivity was 74.51%. Its activity was still lower than that of the example, and the selectivity was slightly higher than that of the example. The reason was that the molar number of tris(4-formylphenyl)amine in the comparative example was much higher than that in the example, and the number of synthesized organic cages was too large, resulting in a corresponding decrease in the active components in each organic cage and insufficient activity of a single active center. Due to the small scale of the palladium active center and strong adsorption of CO, its selectivity was slightly better accordingly.

[0083] Example 2

[0084] This example provides a hydrogenation method with process conditions: space velocity 8000 / h, the reaction process is two-stage adiabatic, the reaction pressure is 4.0 MPa, the inlet temperature of the first stage is 85 °C, and the inlet temperature of the second-stage reactor is 100 °C. The preparation conditions and process of the catalyst used are as follows:

[0085] Support: A commercially available spherical alumina support with a diameter of 4.0 mm was used. After calcination at 1120 °C for 4 h, the water absorption rate was 55%, and the specific surface area was 15 m 2 / g. 100 g of this support was weighed.

[0086] Catalyst preparation:

[0087] (1) 0.11 g of silver nitrate was dissolved in 55 ml of deionized water to obtain an aqueous solution containing silver. 100 g of the calcined support was impregnated in the prepared solution. After all the solution was absorbed, it was dried at 120 °C and calcined at 550 °C for 4 hours to obtain a semi-finished catalyst D;

[0088] (2) 55.44 g of lactic acid was weighed and mixed with the semi-finished catalyst D, and kept at a constant temperature of 130 °C for 15 hours to obtain a semi-finished catalyst E; polylactic acid accounted for 80% of the pore volume of the support;

[0089] (3) Mix 13.33 mg of tris(4-formylphenyl)amine with 0.0088 mg of dichloroacetic acid, dissolve them in 50 ml of dichloroethane, then mix with semi-finished catalyst E, stir and dropwise add a mixed solution of 21.25 mg of 2-chloro-4,4”-diaminoterphenyl and 10 ml of dichloroethane. Let the mixture stand at room temperature for 200 hours, pour out the residual liquid, wash with ethanol and deionized water respectively, and dry to obtain semi-finished catalyst F;

[0090] (4) Dissolve 42.19 mg of palladium acetate in 50 mL of dichloromethane. Wait until the palladium acetate is completely dissolved to obtain a palladium acetate solution. Immerse semi-finished catalyst F in 50 mL of ethanol solution, and dropwise add the palladium acetate solution to the mixture of semi-finished catalyst F and ethanol while stirring. After all the solution is added, let it stand for 4 hours. Pour out the residual liquid and wash with deionized water. Dry at 120 °C and calcine at 430 °C for 6 hours to obtain the desired catalyst.

[0091] Determined by atomic absorption spectrometry, in the catalyst prepared in Example 2, based on 100% of the mass of the carrier, the Pd content is 0.02% and the Ag content is 0.07%.

[0092] The pore size of the organic cage synthesized in Example 2 determined by the BET method, the maximum pore size is 3.48 nm and the minimum pore size is 2.70 nm.

[0093] Catalyst reduction: Hydrogen, keep the temperature at 150 °C for 4 hours, hydrogen space velocity: 300 / h.

[0094] Comparative Example 2

[0095] This comparative example provides a hydrogenation method with process conditions: space velocity 8000 / h, the reaction process is two-stage adiabatic, the reaction pressure is 4.0 MPa, the inlet temperature of the first stage is 85 °C, and the inlet temperature of the second-stage reactor is 100 °C.

[0096] Among them, the preparation conditions of the catalyst used are the same as those in Example 2, the difference is that Ag is not loaded. The preparation process of the catalyst in Comparative Example 2 is as follows:

[0097] Carrier: Use the same carrier as in Example 2.

[0098] Catalyst preparation:

[0099] (1) Weigh 55.44 g of lactic acid and mix it with 100 g of the calcined carrier, keep the temperature at 130 °C for 15 hours to obtain semi-finished catalyst E1, and the polylactic acid accounts for 80% of the pore volume of the carrier;

[0100] (2) Mix 13.33 mg of tris(4-formylphenyl)amine with 0.0088 mg of dichloroacetic acid, dissolve them in 50 ml of dichloroethane, then mix with semi-finished catalyst E1, stir and dropwise add a mixed solution of 21.25 mg of 2-chloro-4,4”-diaminoterphenyl and 10 ml of dichloroethane. Let the mixture stand at room temperature for 200 hours, pour out the residual liquid, wash with ethanol and deionized water respectively, and dry to obtain semi-finished catalyst F1;

[0101] (3) Dissolve 42.19 mg of palladium acetate in 50 mL of dichloromethane. Wait until the palladium acetate is completely dissolved to obtain a palladium acetate solution. Immerse semi-finished catalyst F1 in 50 mL of ethanol solution, and dropwise add the palladium acetate solution to the mixture of semi-finished catalyst F and ethanol while stirring. After all the solution is added, let it stand for 4 hours. Pour out the residual liquid, wash with deionized water, dry at 120 °C, and calcine at 430 °C for 6 hours to obtain the desired catalyst.

[0102] Determined by atomic absorption spectrometry, in the catalyst prepared in Comparative Example 2, based on 100% of the mass of the carrier, the Pd content is 0.02%.

[0103] Catalyst reduction: Hydrogen, keep the temperature at 150 °C for 4 hours, hydrogen space velocity: 300 / h.

[0104] Table 3 Hydrogenation material composition

[0105] Component <![CDATA[H 2 > <![CDATA[C 2 H 4 > <![CDATA[C 2 H 2 > <![CDATA[C 3 H 6 > Methylacetylene and Propadiene CO Volume Content, % 30 30 0.4 5 0.2 0.06

[0106] Table 4 Hydrogenation results of Example 2 and Comparative Example 2

[0107]

[0108] Judging from the evaluation results, at the initial stage of the reactor, the acetylene conversion rate in the first stage of Example 2 is 65.49%, and the ethylene selectivity is 86.54%; in the comparative example, the acetylene conversion rate in the first stage is slightly higher, at 67.27%, but the selectivity is 77.31%, which is significantly lower than that of Example 2.

[0109] After 1000 hours, the acetylene in the second stage of Example 2 is completely converted, while the acetylene in the second stage of the comparative example is not completely converted. Although the difference from 100% conversion is not large, it is still unqualified. In terms of selectivity, after 1000 hours, the ethylene selectivity and propylene selectivity in the second stage of Example 2 are significantly higher than those of the comparative example. The reason may be that component Ag is not added in the comparative example, and the intrinsic selectivity of the catalyst is poor. During the operation, the difference in the effects between the comparative example and Example 2 becomes larger and larger.

[0110] Example 3

[0111] This example provides a hydrogenation method with process conditions: space velocity of 15,000 / h, single-stage isothermal reaction process, reaction pressure of 3.2 MPa, and reactor inlet temperature of 80 °C.

[0112] Among them, the preparation conditions and process of the catalyst used are as follows:

[0113] Support: Commercially available spherical alumina with a diameter of 3 mm. After calcination at 1160 °C for 4 h, the water absorption rate is 48%, and the specific surface area is 8.5 m 2 / g. Weigh 100 g of this support.

[0114] Catalyst preparation:

[0115] (1) Dissolve 0.126 g of silver nitrate in 48 ml of deionized water to obtain an aqueous solution containing silver. Immerse 100 g of the calcined support in the prepared solution. After the solution is completely absorbed, dry at 120 °C and calcine at 520 °C for 4 hours to obtain semi-finished catalyst G;

[0116] (2) Weigh 57.47 g of lactic acid and mix it with semi-finished catalyst G. Keep it at a constant temperature of 125 °C for 20 hours to obtain semi-finished catalyst H, where polylactic acid accounts for 95% of the pore volume of the support;

[0117] (3) Take 10 mg of tris(4-formylphenyl)amine and mix it with 0.005 mg of dichloroacetic acid, dissolve them in 50 ml of dichloroethane, then mix with semi-finished catalyst H, stir and dropwise add a mixed solution of 21.48 mg of 2-fluoro-4,4”-diaminoterphenyl and 10 ml of trichloroethane. Let the mixture stand at room temperature for 120 hours, pour out the residual liquid, wash it with ethanol and deionized water respectively, and dry to obtain semi-finished catalyst J;

[0118] (4) Dissolve 85.88 mg of palladium acetylacetonate in 50 mL of dichloroethane. Wait until the palladium acetylacetonate is completely dissolved to obtain a palladium acetylacetonate solution. Immerse semi-finished catalyst J in 50 mL of ethanol solution, and drop the palladium acetylacetonate solution into the mixture of semi-finished catalyst J and ethanol while stirring. After the solution is completely added, let it stand for 4 hours. Pour out the solution, wash it with deionized water, dry at 120 °C, and calcine at 400 °C for 4 hours to obtain semi-finished catalyst K.

[0119] (5) Weigh 2.95 g of copper nitrate and dissolve it in 48 g of deionized water. Immerse semi-finished catalyst K in the prepared copper nitrate solution. After the solution is completely absorbed, dry at 120 °C and calcine at 400 °C for 4 hours to obtain the required catalyst.

[0120] Determined by atomic absorption spectrometry, in the catalyst prepared in Example 3, based on 100% of the mass of the support, the Pd content is 0.03%, the Ag content is 0.08%, and the Cu content is 1%.

[0121] The pore size of the organic cage synthesized in Example 3 determined by the BET method, the maximum pore size is 3.40 nm, and the minimum pore size is 2.74 nm.

[0122] Catalyst reduction: Hydrogen, constant temperature at 120 °C for 4 hours, hydrogen space velocity: 500 / h.

[0123] Comparative Example 3

[0124] This comparative example provides a hydrogenation method with process conditions: space velocity 15000 / h, reaction process is single-stage isothermal. Reaction pressure 3.2 MPa, reactor inlet temperature 80 °C.

[0125] Among them: The preparation conditions and process of the catalyst used are:

[0126] Support: The same support as in Example 3 is used.

[0127] Catalyst preparation: The catalyst preparation conditions are the same as in Example 3, except that the volume of polylactic acid is 40% of the pore volume of the support.

[0128] Catalyst preparation:

[0129] (1) Dissolve 0.126 g of silver nitrate in 48 ml of deionized water to obtain an aqueous solution containing silver. Immerse 100 g of the calcined support in the prepared solution. After the solution is completely absorbed, dry at 120 °C and calcine at 520 °C for 4 hours to obtain semi-finished catalyst G1;

[0130] (2) Weigh 24.19 g of lactic acid and mix it with semi-finished catalyst G1. Keep it at a constant temperature of 125 °C for 20 hours to obtain semi-finished catalyst H1, and polylactic acid accounts for 40% of the pore volume of the support;

[0131] (3) Take 10 mg of tris(4-formylphenyl)amine and 0.005 mg of dichloroacetic acid, dissolve them in 50 ml of dichloroethane, then mix with semi-finished catalyst H1, stir and dropwise add a mixed solution of 21.48 mg of 2-fluoro-4,4”-diaminoterphenyl and 10 ml of trichloroethane. Let the mixture stand at room temperature for 120 hours, pour out the residual liquid, wash with ethanol and deionized water respectively, and dry to obtain semi-finished catalyst J1;

[0132] (4) Dissolve 85.88 mg of palladium acetylacetonate in 50 mL of dichloroethane. Wait for the palladium acetylacetonate to completely dissolve to obtain a palladium acetylacetonate solution. Immerse semi-finished catalyst J1 in 50 mL of ethanol solution. Drop the palladium acetylacetonate solution into the mixture of semi-finished catalyst J and ethanol while stirring. After all the solution is added, let it stand for 4 hours. Pour out the solution, wash with deionized water, dry at 120 °C, and calcine at 400 °C for 4 hours to obtain semi-finished catalyst K1.

[0133] (5) Weigh 2.95 g of copper nitrate and dissolve it in 48 g of deionized water. Immerse the semi-finished catalyst K1 into the prepared copper nitrate solution. After the solution is completely absorbed, dry it at 120 °C and calcine it at 400 °C for 4 hours to obtain the required catalyst.

[0134] In the catalyst prepared in Comparative Example 3 determined by atomic absorption spectrometry, based on 100% of the mass of the carrier, the Pd content is 0.03%, the Ag content is 0.08%, and the Cu content is 1%.

[0135] The pore diameter of the organic cage synthesized in Comparative Example 3 measured by the BET method, the maximum pore diameter is 3.40 nm, and the minimum pore diameter is 2.74 nm.

[0136] Catalyst reduction: Hydrogen, keep the temperature constant at 120 °C for 4 hours, hydrogen space velocity: 500 / h.

[0137] Table 5 Hydrogenation material composition

[0138] Component <![CDATA[H 2 > <![CDATA[C 2 H 4 > <![CDATA[C 2 H 2 > <![CDATA[C 3 H 6 > Methylacetylene and Propadiene CO Volume Content, % 20 40 0.5 8 0.4 0.1

[0139] Table 6 Hydrogenation results of Example 3 and Comparative Example 3

[0140]

[0141] From the results in Table 6, the acetylene conversion rate in Example 100 hours is 100%, and the ethylene selectivity reaches 91.23%; the acetylene conversion rate in the comparative example is only 96.26%, and the ethylene selectivity is only 65.61%. The reason for this difference is that the distribution of the organic cage in the comparative example is closer to the inside of the catalyst. Due to the effect of the internal diffusion limitation factor in the gas-phase reaction, the selectivity of the catalyst is not good. Although the acetylene conversion rate in Comparative Example 3 is unqualified, the evaluation results at 100 hours, 1000 hours and 2000 hours are very close, and the performance decay of the catalyst is not obvious, indicating that the addition of Cu plays a role in delaying the performance decay of the catalyst.

[0142] Example 4

[0143] This example provides a hydrogenation method with process conditions: space velocity 22000 / h, and the reaction process is three-stage adiabatic. The reaction pressure is 3.5 MPa, the inlet temperature of the first stage is 60 °C, the inlet temperature of the second reactor is 75 °C, and the inlet temperature of the third stage is 85 °C.

[0144] Among them, the preparation conditions and process of the catalyst used are:

[0145] Carrier: Use a commercially available toothed spherical alumina carrier with a diameter of 4.5 mm. After calcining at 1320 °C for 4 h, the water absorption rate is 38%, and the specific surface area is 1 m 2 / g. Weigh 100 g of this carrier.

[0146] Catalyst Preparation:

[0147] (1) Dissolve 0.157 g of silver nitrate and 5.90 g of copper nitrate in 38 ml of deionized water to obtain an aqueous solution containing silver / copper. Immerse 100 g of the calcined support in the prepared solution. After all the solution is absorbed, dry at 120 °C and calcine at 500 °C for 6 hours to obtain the semi-finished catalyst M;

[0148] (2) Weigh 43.09 g of lactic acid, mix it with the semi-finished catalyst M, heat it to 120 °C with stirring, and keep it at a constant temperature for 20 hours to obtain the semi-finished catalyst N, where the polylactic acid accounts for 90% of the pore volume of the support;

[0149] (3) Take 7 mg of tris(4-formylphenyl)amine and 0.0021 mg of trichloroacetic acid, dissolve them in 40 ml of dichloroethane, then mix them with the semi-finished catalyst N, stir and dropwise add a mixed solution of 9.22 mg of 3-methyl-4,4”-diaminoterphenyl and 10 ml of dichloroethane. Let the mixture stand at room temperature for 150 hours, pour out the residual liquid, wash it with ethanol and deionized water respectively, and dry it to obtain the semi-finished catalyst O;

[0150] (4) Dissolve 100 mg of palladium acetylacetonate in 40 ml of dichloromethane. After the palladium acetylacetonate is completely dissolved, obtain the palladium acetylacetonate solution. Immerse the semi-finished catalyst O in a 50 ml ethanol solution, and drop the palladium acetylacetonate solution into the mixture of the semi-finished catalyst O and ethanol while stirring. After all the palladium acetylacetonate solution is added, let it stand for 4 hours, add 10 ml of 5% hydrazine hydrate solution, and keep it at room temperature for 1 hour to obtain the desired catalyst P.

[0151] Determined by atomic absorption spectrometry, in the catalyst prepared in Example 4, based on the mass of the support being 100%, the Pd content is 0.035%, the Ag content is 0.10%, and the Cu content is 2%.

[0152] The pore size of the organic cage synthesized in Example 4 determined by the BET method, the maximum pore size is 3.38 nm, and the minimum pore size is 2.89 nm.

[0153] Catalyst Reduction: Hydrogen, keep at a constant temperature of 120 °C for 4 hours, hydrogen space velocity: 500 / h.

[0154] Comparative Example 4

[0155] The hydrogenation method provided in this comparative example, process conditions: space velocity 22000 / h, the reaction process is three-stage adiabatic. Reaction pressure 3.5 MPa, the inlet temperature of the first stage is 60 °C, the inlet temperature of the second stage reactor is 75 °C, and the inlet temperature of the third stage is 85 °C.

[0156] The same as the catalyst in Example 4.

[0157] Catalyst reduction: Hydrogen, keep at a constant temperature of 120 °C for 4 hours, hydrogen space velocity: 500 / h.

[0158] In the hydrogenation test, in the material of Comparative Example 4, the CO content was 0.2%. Table 7 shows the material compositions of Example 4 and Comparative Example 4

[0159]

[0160] Table 8 shows the hydrogenation results of Example 4 and Comparative Example 4

[0161]

[0162] From the results in Table 8, when the CO content in the material was 0.09% (V), acetylene could be completely converted at the outlet of the three-stage reactor in the example. However, when the CO content in the material of the comparative example was 0.2%, with the same catalyst, acetylene was not completely converted at the outlet of the three-stage reactor, and the acetylene conversion rates in the first and second stages were lower than those in the corresponding example. This indicates that too high a CO content inhibits the hydrogenation of acetylene and prevents it from being completely converted. After 2000 hours, compared with the example, the selectivities of ethylene and propylene in the comparative example were higher than those in the latter, indicating that an increase in the CO content is beneficial to improving the selectivity.

[0163] Example 5

[0164] This example provides a hydrogenation method with the following process conditions: space velocity 10000 / h, reaction process is single-stage adiabatic, reaction pressure 3.7 MPa, reactor inlet temperature 100 °C.

[0165] Among them, the preparation conditions and process of the catalyst used are as follows:

[0166] Support: Spherical alumina-magnesia support is used, with a magnesia content of 10% and a diameter of 3 mm. After calcination at 1180 °C for 4 h, the water absorption rate is 45%, and the specific surface area is 10.2 m 2 / g. Weigh 100 g of this support.

[0167] Catalyst preparation:

[0168] (1) Dissolve 0.189 g of silver nitrate in 45 ml of deionized water to obtain an aqueous solution containing silver. Immerse 100 g of the calcined support in the prepared solution. After all the solution is absorbed, dry at 120 °C and calcine at 540 °C for 4 hours to obtain the semi-finished catalyst Q;

[0169] (2) Weigh 48.20 g of lactic acid, add it to the semi-finished catalyst Q, heat it to 120 °C with stirring, and keep it at a constant temperature for 20 hours to obtain the semi-finished catalyst N, and the polylactic acid accounts for 85% of the pore volume of the support;

[0170] (3) 12.5 mg of tris(4-formylphenyl)amine and 0.0063 mg of trichloroacetic acid were mixed and dissolved in 50 ml of dichloroethane, and then mixed with the semi-finished catalyst R. The mixture was stirred and a mixed solution of 20.28 mg of 4,4”-diaminoterphenyl and 10 ml of trichloroethane was added dropwise. The mixture was allowed to stand at room temperature for 200 hours, the residual liquid was poured out, and it was washed with ethanol and deionized water respectively, and then dried to obtain the semi-finished catalyst S;

[0171] (4) 71.57 mg of palladium acetylacetonate was dissolved in 50 ml of chloroform. After the palladium acetylacetonate was completely dissolved, a palladium acetylacetonate solution was obtained. The semi-finished catalyst S was immersed in 50 ml of ethanol solution, and the palladium acetylacetonate solution was added dropwise to the mixture of the semi-finished catalyst S and ethanol while stirring. After all the palladium acetylacetonate solution was added, it was allowed to stand for 4 hours, washed with deionized water, dried at 120 °C, and calcined at 300 °C for 2 hours to obtain the semi-finished catalyst T.

[0172] (5) 11.80 g of copper nitrate was dissolved in 45 ml of deionized water. The semi-finished catalyst T was immersed in the prepared copper nitrate solution. After the solution was completely absorbed, it was allowed to stand for 4 hours, dried at 120 °C, 50 ml of deionized water was added, 5 ml of 40% formaldehyde aqueous solution was added, and it was kept at a constant temperature of 50 °C for 20 minutes. The solution was poured out, washed with deionized water, and dried at 120 °C to obtain the required catalyst.

[0173] In the catalyst prepared in Example 5 determined by atomic absorption spectrometry, based on the mass of the carrier being 100%, the Pd content was 0.025%, the Ag content was 0.12%, and the Cu content was 4%.

[0174] The pore size of the organic cage synthesized in Example 5 determined by the BET method, the maximum pore size was 3.47 nm, and the minimum pore size was 2.71 nm.

[0175] Catalyst reduction: hydrogen, kept at a constant temperature of 120 °C for 4 hours, hydrogen space velocity: 500 / h.

[0176] Comparative Example 5

[0177] This comparative example provided a hydrogenation method, process conditions: space velocity 10000 / h, reaction process was single-stage adiabatic, reaction pressure 3.7 MPa, reactor inlet temperature 100 °C.

[0178] Among them, the preparation conditions and process of the catalyst used were:

[0179] Support: The same support as in Example 5 was used,

[0180] Catalyst preparation: The difference from Example 5 was that the calcination temperature in step (4) was 180 °C

[0181] (1) Dissolve 0.189 g of silver nitrate in 45 ml of deionized water to obtain an aqueous solution containing silver. Immerse 100 g of the calcined support in the prepared solution. After all the solution is absorbed, dry it at 120 °C and calcine it at 540 °C for 4 hours to obtain the semi-finished catalyst Q1;

[0182] (2) Weigh 48.20 g of lactic acid, add the semi-finished catalyst Q1, heat it to 120 °C with stirring, and keep it at a constant temperature for 20 hours to obtain the semi-finished catalyst R1, and the polylactic acid accounts for 85% of the pore volume of the support;

[0183] (3) Take 12.5 mg of tris(4-formylphenyl)amine and 0.0063 mg of trichloroacetic acid, dissolve them in 50 ml of dichloroethane, then mix them with the semi-finished catalyst R1, stir and dropwise add a mixed solution of 20.28 mg of 4,4”-diaminoterphenyl and 10 ml of trichloroethane. Let the mixture stand at room temperature for 200 hours, pour out the residual liquid, wash it with ethanol and deionized water respectively, and dry it to obtain the semi-finished catalyst S1;

[0184] (4) Dissolve 71.57 mg of palladium acetylacetonate in 50 ml of chloroform. Wait until the palladium acetylacetonate is completely dissolved to obtain a palladium acetylacetonate solution. Immerse the semi-finished catalyst S1 in 50 ml of ethanol solution. Drop the palladium acetylacetonate solution into the mixture of the semi-finished catalyst S1 and ethanol, and stir at the same time. After all the palladium acetylacetonate solution is added, let it stand for 4 hours, pour out the residual liquid, wash it with deionized water, dry it at 120 °C, and calcine it at 180 °C for 2 hours to obtain the semi-finished catalyst T1.

[0185] (5) Dissolve 11.80 g of copper nitrate in 45 ml of deionized water. Immerse the semi-finished catalyst T1 in the prepared copper nitrate solution. After all the solution is absorbed, let it stand for 4 hours, dry it at 120 °C, add 50 ml of deionized water, add 5 ml of a 40% formaldehyde aqueous solution, keep it at a constant temperature of 50 °C for 20 minutes, pour out the solution, wash it with deionized water, and dry it at 120 °C to obtain the required catalyst.

[0186] Determined by atomic absorption spectrometry, in the catalyst prepared in Example 5, based on the mass of the support being 100%, the Pd content is 0.025%, the Ag content is 0.12%, and the Cu content is 4%.

[0187] The pore diameter of the organic cage synthesized in Comparative Example 5 measured by the BET method, the maximum pore diameter is 3.47 nm, and the minimum pore diameter is 2.71 nm.

[0188] Catalyst reduction: hydrogen, keep it at a constant temperature of 120 °C for 4 hours, hydrogen space velocity: 500 / h.

[0189] Table 9 Hydrogenation material composition of Example 5 and Comparative Example 5

[0190] Composition <![CDATA[H 2 > <![CDATA[C 2 H 4 > <![CDATA[C 2 H 2 > <![CDATA[C 3 H 6 > Methylacetylene and Propadiene CO Volume Content, % 30 32 0.45 10 0.9 0.06

[0191] Table 10 Hydrogenation Results of Example 5 and Comparative Example 5

[0192]

[0193] In the case of a single-stage reactor, the catalyst needs to have good activity and selectivity to completely convert acetylene. From the results in Table 10, in Example 5, acetylene at the reactor outlet was completely converted, while in the comparative example, acetylene was not completely converted and there was a trace amount of residue. The reason is that in the comparative example, the calcination temperature in step (4) was low, and the organic polymer was not completely decomposed, resulting in that in part of step (5), Cu could not enter the inner pores of the catalyst and could only be entirely loaded on the outer pores, covering part of the palladium, leading to insufficient acetylene removal activity of the catalyst.

[0194] The selectivity of the comparative example was also lower than that of the example. It may be that the outer pores were loaded with too high a content of Cu, forming active centers for olefin hydrogenation, and ethylene hydrogenation occurred at these active centers. From the data of 2000 hours for Comparative Example 5 and Example 5, the conversion rate and selectivity only decreased slightly, indicating that the loading of Cu indeed has the effect of improving the stability of the catalyst. That is, the Cu active centers hydrogenate the hydroformylation reaction products, reducing the rate of catalyst coking.

[0195] Example 6

[0196] This example provides a hydrogenation method with process conditions: space velocity of 16000 / h, the reaction process is two-stage adiabatic, the reaction pressure is 3.5 MPa, from the start to 2000 hours, the inlet temperature of the first-stage reactor is 65 °C, and the inlet temperature of the second stage is 85 °C. After 2000 hours, the inlet temperature of the second stage in the comparative example was increased to 100 °C.

[0197] Among them, the preparation conditions and process of the catalyst used are:

[0198] Support: A commercially available spherical alumina support with a diameter of 2 mm is used. After calcination at 1300 °C for 4 h, the water absorption rate is 42%, and the specific surface area is 4.9 m 2 / g. 100 g of this support is weighed.

[0199] Catalyst preparation:

[0200] (1) 0.236 g of silver nitrate is dissolved in 42 ml of deionized water to obtain an aqueous solution containing silver. The 100 g of the calcined support is impregnated in the prepared solution. After all the solution is absorbed, it is dried at 120 and calcined at 550 °C for 4 hours to obtain a semi-finished catalyst U;

[0201] (2) Weigh 39.69 g of lactic acid and mix it with the semi-finished catalyst U. Keep it at a constant temperature of 130 °C for 15 hours to obtain the semi-finished catalyst V, with polylactic acid accounting for 75% of the carrier pore volume;

[0202] (3) Take 8.57 mg of tris(4-formylphenyl)amine and mix it with 0.0048 mg of difluoroacetic acid. Dissolve them in 50 ml of dichloroethane, then mix with the semi-finished catalyst V. Stir and dropwise add a mixed solution of 14.77 mg of 4,4”-diaminoterphenyl and 10 ml of dichloroethane. Let the mixture stand at room temperature for 120 hours, pour out the residual liquid, wash it with ethanol and deionized water respectively, and dry it to obtain the semi-finished catalyst W;

[0203] (4) Weigh 85.88 mg of palladium acetylacetonate and dissolve it in 50 ml of dichloromethane. Wait until the palladium acetylacetonate is completely dissolved to obtain a palladium acetylacetonate solution.

[0204] Immerse the semi-finished catalyst W in 50 ml of ethanol solution. Drop the prepared palladium acetylacetonate solution into the mixture of the semi-finished catalyst W and methanol while stirring. After all the solution is dropped, let it stand for 6 hours, pour out the solution, add a mixed solution of 25 ml of ethanol and 25 ml of methanol, keep it at a constant temperature of 40 °C for 1 hour, pour out the solution, wash it with deionized water, and dry it at 120 °C to obtain the semi-finished catalyst X.

[0205] (5) Weigh 14.75 g of copper nitrate and dissolve it in 42 ml of deionized water. Immerse the semi-finished catalyst X in the prepared copper nitrate solution. After all the solution is absorbed, let it stand for 4 hours, dry it at 120 °C, add 50 ml of deionized water, add 5 ml of a 40% formic acid aqueous solution, keep it at a constant temperature of 50 °C for 10 minutes, pour out the solution, and dry it at 100 °C to obtain the desired catalyst.

[0206] By atomic absorption spectrometry, the Pd content in the catalyst prepared in Example 7 is 0.03%, the Ag content is 0.15%, and the Cu content is 5%.

[0207] The pore size of the organic cage synthesized in Example 6 measured by the BET method: the maximum pore size is 3.39 nm, and the minimum pore size is 2.79 nm.

[0208] Catalyst reduction: hydrogen, keep it at a constant temperature of 120 °C for 4 hours, hydrogen space velocity: 500 / h.

[0209] Comparative Example 6

[0210] This comparative example provides a hydrogenation method with process conditions: space velocity 16000 / h, the reaction process is two-stage adiabatic, the reaction pressure is 3.5 MPa. From the start to 2000 hours, the inlet temperature of the first-stage reactor is 65 °C, and the inlet temperature of the second stage is 85 °C. After 2000 hours, the inlet temperature of the second stage in the comparative example is increased to 100 °C.

[0211] Among them, the preparation conditions and process of the catalyst used are as follows:

[0212] Support: The same support as in Example 6 is used.

[0213] Catalyst preparation: The preparation conditions are the same as those in Example 6, except that in step (3), 4,4”-diaminobiphenyl with the same molar amount as that of tetraphenyldiamine is used to react with tris(4-formylphenyl)amine to prepare an organic cage.

[0214] Catalyst preparation:

[0215] (1) Dissolve 0.236 g of silver nitrate in 42 ml of deionized water to obtain an aqueous silver-containing solution. Immerse 100 g of the calcined support in the prepared solution. After the solution is completely absorbed, dry at 120 °C and calcine at 550 °C for 4 hours to obtain a semi-finished catalyst U1.

[0216] (2) Weigh 39.69 g of lactic acid and mix it with the semi-finished catalyst U1, and keep it at a constant temperature of 130 °C for 15 hours to obtain a semi-finished catalyst V1, and the polylactic acid accounts for 75% of the pore volume of the support.

[0217] (3) Take 8.57 mg of tris(4-formylphenyl)amine and 0.0048 mg of difluoroacetic acid, dissolve them in 50 ml of dichloroethane, then mix them with the semi-finished catalyst V1, stir and dropwise add a mixed solution of 8.09 mg of 4,4”-diaminobiphenyl and 10 ml of dichloroethane. Let the mixture stand at room temperature for 120 hours, pour out the residual liquid, wash it with ethanol and deionized water respectively, and dry it to obtain a semi-finished catalyst W1.

[0218] (4) Weigh 85.88 mg of palladium acetylacetonate and dissolve it in 50 ml of dichloromethane. Wait until the palladium acetylacetonate is completely dissolved to obtain a palladium acetylacetonate solution.

[0219] Immerse the semi-finished catalyst W1 in 50 ml of an ethanol solution, and drop the prepared palladium acetylacetonate solution into the mixture of the semi-finished catalyst W1 and methanol while stirring. After all the solution is dropped, let it stand for 6 hours, pour out the solution, add a mixed solution of 25 ml of ethanol and 25 ml of methanol, keep it at a constant temperature of 40 °C for 1 hour, pour out the solution, wash it with deionized water, and dry it at 120 °C to obtain a semi-finished catalyst X1.

[0220] (5) Weigh 14.75 g of copper nitrate and dissolve it in 42 ml of deionized water. Immerse the semi-finished catalyst X1 in the prepared copper nitrate solution. After the solution is completely absorbed, let it stand for 4 hours, dry it at 120 °C, add 50 ml of deionized water, add 5 ml of a 40% formic acid aqueous solution, keep it at a constant temperature of 50 °C for 10 minutes, pour out the solution, and dry it at 100 °C to obtain the required catalyst.

[0221] The catalyst prepared in Comparative Example 6 was determined by atomic absorption spectroscopy to have a Pd content of 0.03%, an Ag content of 0.15%, and a Cu content of 5%.

[0222] The pore size of the organic cage synthesized in Comparative Example 6 measured by the BET method has a maximum pore size of 2.14 nm and a minimum pore size of 1.46 nm.

[0223] Catalyst reduction: hydrogen, constant temperature at 120°C for 4 hours, hydrogen space velocity: 500 / h.

[0224] Table 11 Hydrogenation materials of Example 6 and Comparative Example 6

[0225] Composition <![CDATA[H 2 > <![CDATA[C 2 H 4 > <![CDATA[C 2 H 2 > <![CDATA[C 3 H 6 > Methylacetylene and Propadiene CO 0-1000 Volume Content, % 15 29 0.8 9 0.8 0.06 1000-2000 Volume Content, % 15 29 0.8 9 0.8 0.1

[0226] Table 12 Hydrogenation results of Example 6 and Comparative Example 6

[0227]

[0228] From the evaluation results, in Example 6, after 500 hours, the conversion rate of the first stage was 72.26%, the acetylene conversion rate of the second stage reactor was 100%, and the total selectivity was 80.56%; in the comparative example, the acetylene conversion rate was significantly lower, and acetylene could not be completely converted at the second stage inlet temperature of 85°C. After 1000 hours, the CO content in the material was increased to 0.1%. The acetylene conversion rate of the first stage reactor of Example 6 only decreased by less than 4 percentage points, and the second stage reactor could still completely convert acetylene, indicating that Example 6 has a good ability to resist CO content fluctuations; the acetylene conversion rate of the first stage reactor of the comparative example decreased by nearly 15 percentage points, and the acetylene conversion rate of the second stage reactor was only 97.58%, which was a serious acetylene leakage. The results show that the sensitivity of the active center to CO content fluctuations is obviously related to the scale of the active center. The smaller the scale of the active center, the more sensitive it is to CO content fluctuations. After 2000 hours, the inlet temperature of the second stage of the comparative example was increased to 100°C, and acetylene could be completely converted, but the total selectivity decreased significantly, which was 40% lower than that at the inlet temperature of 85°C, and the decline was large. Generally speaking, if the hydrogenation selectivity drops below 50%, it means that after acetylene is hydrogenated to ethylene, most of it is hydrogenated to ethane, and the hydrogenation of ethylene is already very obvious. In the previous hydrogenation reaction, the hydrogen content is very high, and excessive hydrogenation of ethylene may cause temperature runaway, which must be avoided as much as possible. This result indicates that the catalyst activity is insufficient, and simply increasing the reaction temperature may cause the catalyst selectivity to drop and temperature runaway.

[0229] The reason for its insufficient catalytic activity is that monomers with smaller chain segments are used in the synthesis of organic cages. The synthesized organic cage has a small space, the formed active center is small in scale and the activity is insufficient.

[0230] Example 7

[0231] This embodiment provides a hydrogenation method with process conditions: space velocity of 8000 / h, single-stage adiabatic reaction process, reaction pressure of 3.8 MPa, and reactor inlet temperature of 100 °C.

[0232] Among them, the preparation conditions and process of the catalyst used are as follows:

[0233] Support: Commercially available spherical alumina with a diameter of 3 mm. After calcination at 1290 °C for 4 h, the water absorption rate is 40%, and the specific surface area is 4.2 m 2 / g. Weigh 100 g of this support.

[0234] (1) Dissolve 0.11 g of silver nitrate in 40 ml of deionized water to obtain an aqueous solution containing silver. Immerse 100 g of the calcined support in the prepared solution. After all the solution is absorbed, dry at 120 °C and calcine at 500 °C for 4 hours to obtain semi-finished catalyst AA;

[0235] (2) Weigh 33.28 g of 30% aqueous acrylic acid solution, 0.015 g of potassium hypophosphite monohydrate, 0.018 g of copper acetate monohydrate, and 0.12 ml of 30% hydrogen peroxide as an initiator. After mixing evenly, a mixed solution containing acrylic acid is obtained. Immerse semi-finished catalyst AA in the prepared mixed solution. After all the solution is absorbed, transfer it to a reflux flask, heat it to 80 °C with stirring, and keep it at a constant temperature for 1.5 hours to obtain semi-finished catalyst BB, and the polyacrylic acid accounts for 79.23% of the pore volume of the support;

[0236] (3) Take 3.5 mg of tris(4-formylphenyl)amine and 0.0029 mg of difluoroacetic acid, dissolve them in 50 ml of dichloroethane, then mix with semi-finished catalyst BB, stir and dropwise add a mixed solution of 6.94 mg of 2-ethyl-4,4”-diaminoterphenyl and 10 ml of dichloroethane. Let the mixture stand at room temperature for 120 hours, pour out the residual liquid, wash it with ethanol and deionized water respectively, and dry it to obtain semi-finished catalyst CC;

[0237] (4) Weigh 59.07 mg of palladium acetate and dissolve it in 50 ml of chloroform. Wait until the palladium acetate is completely dissolved to obtain a palladium acetate solution. Immerse semi-finished catalyst CC in 50 ml of ethanol solution. Drop the prepared palladium acetate solution into the mixture of semi-finished catalyst CC and ethanol while stirring. Let it stand for 10 hours, pour out the solution, wash it with deionized water, dry at 120 °C, and calcine at 450 °C for 2 hours to obtain semi-finished catalyst DD.

[0238] (5) Weigh 7.87 g of copper nitrate and dissolve it in 55 ml of deionized water. Immerse the semi-finished catalyst DD into the prepared copper nitrate solution. After the solution is completely absorbed, let it stand for 4 hours, dry at 120 °C, add 50 ml of methanol, keep it at a constant temperature of 50 °C for 1 hour. After pouring off the methanol, dry at 120 °C to obtain the desired catalyst.

[0239] By atomic absorption spectrometry, the Pd content in the catalyst prepared in Example 7 is 0.028%, the Ag content is 0.07%, and the Cu content is 1%.

[0240] The pore diameter of the organic cage synthesized in step (3) of Example 7 measured by the BET method has a maximum pore diameter of 3.55 nm and a minimum pore diameter of 2.95 nm.

[0241] Catalyst reduction: Hydrogen, keep at a constant temperature of 120 °C for 4 hours, hydrogen space velocity: 200 / h.

[0242] Comparative Example 7

[0243] This comparative example provides a hydrogenation process with the following process conditions: space velocity 8000 / h, the reaction process is single-stage adiabatic, the reaction pressure is 3.8 MPa, and the reactor inlet temperature is 100 °C.

[0244] Among them, the preparation conditions and process of the catalyst used are as follows:

[0245] Support: Use the same support as in Example 7

[0246] Catalyst preparation: The preparation conditions are the same as in Example 7, except that the calcination temperature in step (4) is 580 °C.

[0247] (1) Dissolve 0.11 g of silver nitrate in 40 ml of deionized water to obtain an aqueous solution containing silver. Immerse 100 g of the calcined support in the prepared solution. After the solution is completely absorbed, dry at 120 °C and calcine at 500 °C for 4 hours to obtain the semi-finished catalyst AA1;

[0248] (2) Weigh 33.28 g of 30% aqueous acrylic acid solution, 0.015 g of potassium hypophosphite monohydrate, 0.018 g of copper acetate monohydrate, and 0.12 ml of 30% hydrogen peroxide as an initiator. After mixing evenly, obtain a mixed solution containing acrylic acid. Immerse the semi-finished catalyst AA1 in the prepared mixed solution. After the solution is completely absorbed, transfer it to a reflux flask and heat it to 80 °C with stirring, keep it at a constant temperature for 1.5 hours to obtain the semi-finished catalyst BB1, and the polyacrylic acid accounts for 79.23% of the pore volume of the support;

[0249] (3) Mix 3.5 mg of tris(4-formylphenyl)amine with 0.0029 mg of difluoroacetic acid, dissolve them in 50 ml of dichloroethane, then mix with the semi-finished catalyst BB1, stir and dropwise add a mixed solution of 6.94 mg of 2-ethyl-4,4”-diaminoterphenyl and 10 ml of dichloroethane. Let the mixture stand at room temperature for 120 hours, pour out the residual liquid, wash with ethanol and deionized water respectively, and dry to obtain the semi-finished catalyst CC1;

[0250] (4) Weigh 59.07 mg of palladium acetate and dissolve it in 50 ml of chloroform. Wait until the palladium acetate is completely dissolved to obtain a palladium acetate solution. Immerse the semi-finished catalyst CC1 in 50 ml of ethanol solution, drop the prepared palladium acetate solution into the mixture of the semi-finished catalyst CC1 and ethanol while stirring, dry at 120 °C, and calcine at 580 °C for 2 hours to obtain the semi-finished catalyst DD1.

[0251] (5) Weigh 7.87 g of copper nitrate and dissolve it in 55 ml of deionized water. Immerse the semi-finished catalyst DD1 in the prepared copper nitrate solution. After the solution is completely absorbed, let it stand for 4 hours, dry at 120 °C, add 50 ml of methanol, keep it at a constant temperature of 50 °C for 1 hour, pour out the methanol, and dry at 120 °C to obtain the required catalyst.

[0252] By atomic absorption spectrometry, the Pd content in the catalyst prepared in Comparative Example 7 is 0.028%, the Ag content is 0.07%, and the Cu content is 1%.

[0253] The pore size of the organic cage synthesized in step (3) of Comparative Example 7 measured by the BET method has a maximum pore size of 3.55 nm and a minimum pore size of 2.95 nm.

[0254] Catalyst reduction: Hydrogen, keep at a constant temperature of 120 °C for 4 hours, hydrogen space velocity: 200 / h.

[0255] Table 13 Hydrogenation material composition of Example 7 and Comparative Example 7

[0256] Composition <![CDATA[H 2 > <![CDATA[C 2 H 4 > <![CDATA[C 2 H 2 > <![CDATA[C 3 H 6 > Methylacetylene and Propadiene CO Volume Content, % 21 37 0.7 11 1.2 0.08

[0257] Table 14 Hydrogenation results of Example and Comparative Example 7

[0258]

[0259] In Comparative Example 7, when the calcination temperature in step (4) reached 580 °C, the organic cage structure disintegrated, palladium agglomerated to form larger active centers, the activity of some individual active centers was too high, the selectivity was insufficient, and the too large active centers also led to a very intense hydrogenation dimerization reaction. Although the activity can meet the standard in 1500 hours, the selectivity decreased significantly. By 2500 hours, the acetylene conversion rate of the comparative example could no longer reach 100%.

[0260] Example 8

[0261] This example provides a hydrogenation method with process conditions: space velocity of 10,000 / h, a three-stage adiabatic reaction process, a reaction pressure of 3.3 MPa, and the reactor inlet temperatures: 70 °C for the first stage, 80 °C for the second stage, and 90 °C for the third stage.

[0262] Among them, the preparation conditions and process of the catalyst used are as follows:

[0263] Support: Commercially available spherical alumina with a diameter of 4.5 mm is used. After calcination at 1150 °C for 4 h, the water absorption rate is 52%, and the specific surface area is 12.2 m 2 / g. Weigh 100 g of this support.

[0264] Catalyst preparation:

[0265] (1) Dissolve 0.28 g of silver nitrate in 52 ml of deionized water to obtain an aqueous silver-containing solution. Immerse the 100 g of the calcined support in the prepared solution. After all the solution is absorbed, dry at 120 °C and calcine at 520 °C for 4 hours to obtain the semi-finished catalyst EE.

[0266] (2) Weigh 48.6 g of 30% aqueous acrylic acid solution, 0.018 g of potassium hypophosphite monohydrate, 0.02 g of copper acetate monohydrate, and 0.15 ml of 30% hydrogen peroxide as initiators. After mixing evenly, a mixed solution containing acrylic acid is obtained. Immerse the semi-finished catalyst EE in the prepared mixed solution. After all the solution is absorbed, transfer it to a reflux flask and heat it to 80 °C with stirring and keep it at a constant temperature for 2 hours to obtain the semi-finished catalyst FF, and the polyacrylic acid accounts for 88.83% of the pore volume of the support.

[0267] (3) Take 4 mg of tris(4-formylphenyl)amine and 0.004 mg of difluoroacetic acid, dissolve them in 55 ml of dichloroethane, then mix with the semi-finished catalyst FF, stir and dropwise add a mixed solution of 8.11 mg of 4,4”-diaminoterphenyl and 10 ml of dichloroethane. Let the mixture stand at room temperature for 100 hours, pour out the residual liquid, wash it with ethanol and deionized water respectively, and dry to obtain the semi-finished catalyst GG.

[0268] (4) Weigh 84.39 mg of palladium acetate and dissolve it in 55 ml of chloroform. Wait until the palladium acetate is completely dissolved to obtain a palladium acetate solution. Immerse the semi-finished catalyst GG in 50 ml of methanol solution, and drop the prepared palladium acetate solution into the mixture of the semi-finished catalyst GG and methanol while stirring. After all the solution is added, let it stand for 5 hours, pour out the residual liquid, dry at 120 °C, and calcine at 400 °C for 2 hours to obtain the semi-finished catalyst HH.

[0269] (5) Weigh 8.85 g of copper nitrate and dissolve it in 52 ml of deionized water. Immerse the semi-finished catalyst HH into the prepared copper nitrate solution. After the solution is completely absorbed, let it stand for 4 hours, dry at 120 °C, add 25 ml of 40% aqueous formaldehyde solution and 30 ml of 20% aqueous acetaldehyde solution, keep it at a constant temperature of 40 °C for 30 minutes, pour out the solution, wash it with deionized water, and dry at 120 °C to obtain the desired catalyst.

[0270] By atomic absorption spectrometry, the Pd content in the catalyst prepared in Example 8 is 0.04%, the Ag content is 0.18%, and the Cu content is 3.0%.

[0271] The pore size of the organic cage synthesized in Example 8 measured by the BET method has a maximum pore size of 3.60 nm and a minimum pore size of 2.81 nm.

[0272] Catalyst reduction: Hydrogen, keep at a constant temperature of 120 °C for 4 hours, hydrogen space velocity: 200 / h

[0273] Comparative Example 8

[0274] This comparative example provides a hydrogenation method with process conditions: space velocity 4000 / h, the reaction process is three-stage adiabatic, the reaction pressure is 3.3 MPa, and the reactor inlet temperature: 60 °C for the first stage, 70 °C for the second stage, and 80 °C for the third stage.

[0275] The catalyst used is the same as that in Example 8.

[0276] Catalyst reduction: Hydrogen, keep at a constant temperature of 120 °C for 4 hours, hydrogen space velocity: 200 / h.

[0277] Table 15 Hydrogenation material composition of Example 8 and Comparative Example 8

[0278] Composition <![CDATA[H 2 > <![CDATA[C 2 H 4 > <![CDATA[C 2 H 2 > <![CDATA[C 3 H 6 > Methylacetylene and Propadiene CO Volume Content, % 18 25 0.85 10 1.1 0.14

[0279] Table 16 Hydrogenation results of Example 8 and Comparative Example 8

[0280]

[0281] When the inlet temperature of the first stage in the comparative example was 70 °C, a runaway temperature occurred, indicating that at this temperature, the catalytic activity of the comparative example was too high and the selectivity was poor. Therefore, the temperatures of each stage in the example were reduced by 10 °C for evaluation.

[0282] From the results in Table 16, at a space velocity of 4000 / h in the comparative example, although the CO in the feedstock reached a maximum of 0.14%, the acetylene conversion rate at the inlet of the first-stage reactor at a temperature of 60°C was already as high as 74.36%, indicating excessive activity. After 1000 hours, its acetylene conversion rate had decreased significantly, indicating that some by-products were still generated in the first stage of the comparative example, or the C4 fraction in the feedstock underwent a polymerization reaction in the first-stage reactor. The selectivity was also 10 percentage points lower than that of the example; the acetylene conversion rate in the second stage of the comparative example was close to 100%, but the selectivity was more than 10 percentage points lower than that of the second stage of the example; the acetylene content at the inlet of the third stage of the comparative example was already very low, and the main reaction that occurred was the hydrogenation of ethylene, and the selectivity was negative.

[0283] The overall selectivity of the third stage was 84.35% in the example, which was an ideal data; while the selectivity of the comparative example was 59.26%, which was 25 percentage points lower than that of the example, and the loss of ethylene could no longer be ignored.

[0284] The space velocity is a relatively critical indicator for the pre-hydrogenation reaction. When the space velocity is high, the heat removal in the reactor is fast, and the temperature rise in the reactor is low. On the contrary, when the space velocity is too low, the reaction heat cannot be removed in time, which not only affects the selectivity but may even lead to a runaway temperature in the reactor, resulting in extremely serious economic losses.

[0285] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding changes and deformations should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for hydrogenating C1-C3 fractions, wherein the C1-C3 fractions contain, by volume, H 2 10% - 30%, C 2 H 4 25% - 40%, C 2 H 2 0.4% - 0.9%, C 3 H 6 5% - 11%, PDMA 0.2% - 1.2%, CO 0.04% - 0.14%, and the rest are methane, ethane and propane. The catalyst used in the hydrogenation method includes a carrier, an active component and an organic cage. It is characterized in that the active component contains Pd and Ag. Based on the mass of the carrier being 100%, the content of Pd is 0.02 - 0.04%, and the content of Ag is 0.07 - 0.18%. The active component Pd is loaded in the organic cage, and the size of the organic cage is 2.7 - 3.6 nm.

2. The method for hydrogenating C1 - C3 fractions according to claim 1, It is characterized in that the active component further contains Cu. Based on the mass of the carrier being 100%, the content of Cu is 1 - 5%.

3. The method for hydrogenating C1 - C3 fractions according to claim 1, It is characterized in that The specific surface area of the catalyst is 1 to 15 m 2 / g.

4. The method for hydrogenating C1 - C3 fractions according to claim 1, catalyst, It is characterized in that during the preparation of the catalyst, the organic cage is synthesized first and then Pd is loaded.

5. The method for hydrogenating C1 - C3 fractions according to claim 1, It is characterized in that during the preparation of the catalyst, Ag is loaded before the synthesis of the organic cage.

6. The method for hydrogenating C1 - C3 fractions according to claim 2, It is characterized in that Cu is loaded simultaneously with Ag before the loading of Pd, or is loaded alone after the loading of Pd.

7. The method for hydrogenating C1 - C3 fractions according to claim 6, It is characterized in that after the loading of Pd or the separate loading of Cu, a reducing agent is added for liquid - phase reduction. The reducing agent is one or several of hydrazine hydrate, formic acid, formaldehyde, methanol, ethanol, acetaldehyde, etc.

8. The method for hydrogenating C1 - C3 fractions according to claim 1, It is characterized in that the preparation method of the organic cage is as follows: Ag is loaded on the carrier to obtain a semi - finished catalyst, a hydrophilic polymerizable monomer is mixed with the semi - finished catalyst after Ag loading, and the polymerizable monomer undergoes a polymerization reaction to obtain a semi - finished catalyst containing a polymer; tris(4 - formylphenyl)amine and haloacetic acid are mixed, dissolved in a haloalkane, and then mixed with the semi - finished catalyst containing the polymer. A mixed solution of 4,4'' - diaminoquaterphenyl and a haloalkane is added dropwise, and after standing, when the reaction is complete, the residual liquid is poured out, washed, and dried to obtain a semi - finished catalyst containing an organic cage.

9. The method for hydrogenating C1 - C3 fractions according to claim 8, It is characterized in that the volume of the polymer is 70 - 95% of the pore volume of the carrier, preferably 75 - 95%.

10. The method for hydrogenating C1 - C3 fractions according to claim 8, It is characterized in that the hydrophilic polymerizable monomer is acrylic acid and / or lactic acid.

11. The method for hydrogenating C1 - C3 fractions according to claim 8, It is characterized in that the 4,4'' - diaminoquaterphenyl is substituted or unsubstituted 4,4'' - diaminoquaterphenyl, and the substituent is a halogen or an alkyl group.

12. The method for hydrogenating C1 - C3 fractions according to claim 8, It is characterized in that the molar ratio of 4,4'' - diaminoquaterphenyl to tris(4 - formylphenyl)amine is 1.3 - 2.0:1, and the mass ratio of tris(4 - formylphenyl)amine to haloacetic acid is 1000 - 3000:

1.

13. The method for hydrogenating C1 - C3 fractions according to claim 8, It is characterized in that The method for loading Pd is as follows: adding an organopalladium salt into an organic solvent to obtain an organopalladium precursor solution; immersing a carrier containing an organic cage into an alcohol solution; dropping the organopalladium precursor solution into a mixture of the carrier containing the organic cage and the alcohol solution while stirring; standing after dropping; pouring off the solution; washing, drying, calcining or performing liquid-phase reduction to obtain a Pd-loaded catalyst.

14. The method for hydrogenating C1-C3 fractions according to claim 13 It is characterized in that The mass ratio of palladium in the organopalladium salt to the mass of tris(4-formylphenyl)amine is 1.5-10:

1.

15. The method for hydrogenating C1-C3 fractions according to claim 13 It is characterized in that The calcination temperature is higher than the polymer decomposition temperature and lower than or equal to 450 °C, preferably lower than or equal to 430 °C.

16. The method for hydrogenating C1-C3 fractions according to claim 2 It is characterized in that Ag and Cu are loaded in an impregnation manner.

17. The method for hydrogenating C1-C3 fractions according to any one of claims 1 to 13 It is characterized in that The space velocity of the hydrogenation reaction is 8000-22000 / h, the reaction pressure is 3.0-4.0 MPa, and the reactor inlet temperature is 65-100 °C.

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