A selective hydrogenation catalyst for phenylacetylene, its preparation method and application

Abstract

This invention provides a selective hydrogenation catalyst for phenylacetylene, its preparation method, and its application. Based on 100% by mass, the catalyst comprises 8-18% nickel, 0.5-4% zinc, with the balance being a support; wherein some nickel is impregnated onto the support, and the remaining nickel and zinc are distributed on the surface of the support through hydrothermal treatment. This selective hydrogenation catalyst for phenylacetylene exhibits high activity and high selectivity in the selective hydrogenation reaction of phenylacetylene and has the advantage of not easily agglomerating after high-temperature reduction.

Description

Technical Field

[0001] This invention belongs to the field of catalysts, specifically relating to a selective hydrogenation catalyst for phenylacetylene, its preparation method, and its application. Background Technology

[0002] Styrene (ST) is an important monomer for the production of polystyrene, ABS resin, styrene-butadiene rubber, etc. Ethylbenzene dehydrogenation is the main preparation method, but it suffers from high production costs. In recent years, with the large-scale production of ethylene, extracting styrene from the C8 fraction, a byproduct of ethylene cracking, has become a promising new route to increase styrene production.

[0003] Taking a 1000kt / a ethylene unit as an example, it can produce about 20-40kt of styrene per year, and at the same time recover mixed xylene, so that the cracked C8 fraction can be upgraded from fuel value to chemical value. At the same time, due to the separation of the C8 fraction, the load on the subsequent hydrogenation unit of cracked gasoline is reduced, hydrogen consumption is reduced, and the poisoning of cracked gasoline hydrogenation catalyst caused by styrene polymerization is avoided.

[0004] The current method for recovering styrene from cracked gasoline is extractive distillation, but this cracked C8 fraction contains 4000-15000 μg·g⁻¹. -1 The presence of phenylacetylene (PA) in styrene is problematic. While ST and PA have similar chemical structures and interactions with the extractive distillation solvent, existing extractive distillation processes cannot effectively separate ST and PA. The presence of these phenylacetylene components not only increases catalyst consumption during styrene anionic polymerization and affects chain length and polymerization rate, but also impacts the color, odor, and overall properties of the polymerized product. Therefore, selective hydrogenation of phenylacetylene is necessary before extracting styrene from ethylene cracking C8 fractions. Since C8 fractions contain 25-45% styrene, minimizing styrene loss during hydrogenation is crucial. The phenylacetylene content and styrene loss in the hydrogenated product determine the efficiency of styrene recovery processes from cracked gasoline C8 fractions.

[0005] Currently, over 80% of the styrene selective hydrogenation catalysts used in industrially applied styrene extraction units are nickel-based catalysts. These are prepared using the conventional equal-volume impregnation method. Before use, they typically require high-temperature activation in flowing hydrogen to reduce NiO to metallic Ni particles. This can cause Ni particle agglomeration and sintering, leading to decreased stability and selectivity. Therefore, researchers have improved the selective hydrogenation performance of supported Ni-based catalysts by adding additives and modifying preparation methods. To address this issue, existing patents and literature report two approaches: firstly, modifying the support to modulate the interaction between the support and the active component; and secondly, adding additives such as Zn, Cu, Mg, Co, or Sn to modulate the geometry and electronic structure of the Ni active sites to improve the catalyst's selective hydrogenation performance. While these methods have shown some effectiveness in improving styrene selectivity, there is still room for improvement, and achieving both high activity and high selectivity simultaneously remains challenging.

[0006] CN107954814A relates to a method for selective hydrogenation of phenylacetylene from a C8 fraction. The method uses cracked C8 fraction and hydrogen, a byproduct of ethylene production via steam cracking, as feedstock. The reaction is carried out at a temperature of 10-80℃, a pressure of 0.1-2.0 MPa, and a fresh oil volume hourly space velocity (VHSV) of 0.5-2.0 h⁻¹. -1 Under conditions where the hydrogen / oil volume ratio is 5-20:1, the feedstock reacts with the sulfur-containing catalyst, converting the phenylacetylene component in the feedstock into styrene. The sulfur content in the sulfur-containing catalyst is 0.01-5% by weight. The active component of the sulfur-containing catalyst is selected from at least one of nickel, copper, and palladium. However, the degree of poisoning of each type of catalyst has a significant impact on the selectivity of the catalyst, which has not been described in detail.

[0007] CN1087892A discloses a method and apparatus for purifying phenylacetylene from a styrene stream using hydrogenation. It employs a nitrogen and hydrogen mixed gas to reduce the catalyst, uses ethylbenzene dehydrogenation exhaust gas to provide hydrogen, and uses a multi-stage catalytic reactor to hydrogenate the phenylacetylene impurities to styrene. However, the patent only describes a selective hydrogenation deacetylene method for low concentrations, such as 300 ppm, while the phenylacetylene content in the C8 fraction of cracked gasoline is typically above 6000 ppm, and the hydrogenation rate for phenylacetylene is approximately 95%.

[0008] CN101475439A relates to a method for selective hydrogenation of phenylacetylene using a composite bed in the presence of styrene. The method utilizes hydrocarbon fractions containing phenylacetylene as feedstock, and operates at a reaction temperature of 15-100°C and a weight hourly space velocity (WHSV) of 0.01-100 h⁻¹. -1Under conditions where the hydrogen / phenylacetylene molar ratio is 1-30:1 and the reaction pressure is -0.08 to 5.0 MPa, the raw material is sequentially passed through a composite bed reactor containing catalyst A and catalyst B, and the phenylacetylene in the reaction effluent is hydrogenated to styrene. Catalyst A is selected from nickel-based catalysts, and catalyst B is selected from at least one of palladium-based or copper-based catalysts. The loading ratio of catalyst A to catalyst B is 0.5-5:1, but the pretreatment conditions of the two types of composite catalysts are quite different.

[0009] CN101475438A relates to a method for selective hydrogenation of phenylacetylene in the presence of styrene, using a hydrocarbon fraction containing phenylacetylene as feedstock, and reacting at a temperature of 15-100℃ and a weight hourly space velocity of 0.01-100 h⁻¹. -1 Under conditions where the hydrogen / phenylacetylene molar ratio is 1-30:1 and the reaction pressure is -0.08 to 5.0 MPa, the raw material is contacted with a carbon oxide catalyst, and the phenylacetylene in the reaction effluent is hydrogenated to styrene. The carbon content in the carbon oxide catalyst is 0.02-8% by weight of the catalyst. The carbon oxide catalyst is a catalyst obtained by modifying a nickel-based catalyst or a palladium-based catalyst with a certain amount of carbon deposition.

[0010] CN108865241A provides a method for selectively hydrotreating phenylacetylene using the C8 fraction of cracked gasoline as feedstock. The C8 fraction is preheated before being fed into a fixed-bed hydrotreating reactor using a bottom-feed method. The reactor is loaded with a catalyst, and the hydrotreating process conditions are: inlet temperature 10-70℃, space velocity 0.1-6.0 h⁻¹. -1 The pressure is between 0.1-2.0 MPa, and the volume ratio of hydrogen to fresh oil is 1-100:1; the hydrogenated product is used as a raw material for styrene extraction.

[0011] CN114181032A relates to a method for selective hydrogenation of C8 fraction to remove phenylacetylene, comprising mixing the C8 fraction with H2 and then feeding it into an adiabatic reactor, the adiabatic reactor being loaded with a selective hydrogenation catalyst, the hydrogen-to-reactor inlet feed volume ratio being 1-100:1, the reaction inlet temperature being 20-70℃, the reaction pressure being 0.1-1.0 MPa, and the liquid hourly space velocity being 0.1-6 h⁻¹. -1 The reaction products are cooled and then separated in a gas-liquid separator. The selective hydrogenation catalyst is supported on alumina or mainly on alumina, and has a bimodal pore distribution structure, wherein the pore size is 10-25 nm and the pore size is 50-250 nm. The catalyst contains at least Pd, Li, Ni and Cu. Based on the mass of the catalyst, the Pd content is 0.15-0.5 wt%, the mass ratio of Li to Pd is 1-10:1, the Ni content is 0.5-5 wt%, and the mass ratio of Cu to Ni is 0.1-1:1.

[0012] CN102649662A relates to a method for highly selective hydrogenation of phenylacetylene in the presence of styrene, using a hydrocarbon fraction containing phenylacetylene as feedstock, at a reaction temperature of 15-100℃ and a weight hourly space velocity of 0.01-100 h⁻¹. -1 Under conditions where the hydrogen / phenylacetylene molar ratio is 1-30:1 and the reaction pressure is -0.08 to 5.0 MPa, the feedstock is contacted with a metal oxide catalyst, and the phenylacetylene in the reaction effluent is hydrogenated to styrene. The metal oxide catalyst comprises, by weight percentage, the following components: (a) 2-50.0% nickel or its oxide; (b) 0.05-10% at least one element selected from rare earth elements or its oxide; and (c) 40-88% support.

[0013] CN108212134A relates to a silica-containing boehmite catalyst support and its preparation method. The catalyst support is a porous material, specifically a porous silica-alumina material, which is in the form of nanosheets with a silica content of 1-20 wt% and a specific surface area of ​​800-1000 m². 2 / g, pore volume 1.7-4.0cm³ 3 / g, with a most probable pore size of 2-30nm, the reaction endpoint can be controlled by adjusting the mass ratio of sodium aluminate, aluminum sulfate and water glass according to the content of alumina and silicon oxide. This allows for the preparation of nanosheet-shaped silica-containing boehmite catalyst supports with large specific surface area and large pore volume. Summary of the Invention

[0014] To address the aforementioned problems, the present invention aims to provide a selective hydrogenation catalyst for phenylacetylene, its preparation method, and its application. This selective hydrogenation catalyst for phenylacetylene exhibits high activity and high selectivity in the selective hydrogenation reaction of phenylacetylene and has the advantage of not easily agglomerating after high-temperature reduction.

[0015] To achieve the above objectives, the present invention provides a selective hydrogenation catalyst for phenylacetylene, wherein, based on the mass of the selective hydrogenation catalyst for phenylacetylene as 100%, its composition includes 8-18% nickel, 0.5-4% zinc, and the balance being a support; wherein, a portion of the nickel is impregnated and loaded onto the support, and the remaining nickel and zinc are distributed on the surface of the support through hydrothermal treatment.

[0016] According to a specific embodiment of the present invention, preferably, the composition of the phenylacetylene selective hydrogenation catalyst includes 10-15% nickel and 1-2% zinc.

[0017] According to a specific embodiment of the present invention, preferably, the portion of nickel impregnated onto the support accounts for 70-95 wt% of the total nickel content in the phenylacetylene selective hydrogenation catalyst.

[0018] According to a specific embodiment of the present invention, preferably, the support comprises alumina. The alumina used in the catalyst support of the present invention can be commercially available alumina, for example, prepared by the nitric acid process, sulfuric acid process, carbon dioxide process, or other currently available methods. It may contain small amounts of conventionally doped silica, titanium dioxide, zirconium oxide, etc., but the content does not exceed 5 wt%. This support has a suitable specific surface area and reasonable pore distribution, exhibiting good activity and stability. The preparation process of the alumina support can be a commonly used method, such as: during the support preparation process, alumina powder, water, etc., are kneaded, extruded into strips, or rolled into spheres, dried at 80-120℃, and calcined at 800-1100℃ for 4-6 hours.

[0019] According to a specific embodiment of the present invention, preferably, the surface layer of the phenylacetylene selective hydrogenation catalyst has a plate-like structure.

[0020] According to a specific embodiment of the present invention, preferably, the thickness of the sheet-like structure is 5-20 nm, and the width and length are both 300-3000 nm.

[0021] According to a specific embodiment of the present invention, preferably, the thickness of the sheet-like structure is 8-15 nm, and the width and length are both 500-1500 nm.

[0022] According to a specific embodiment of the present invention, preferably, the specific surface area of ​​the phenylacetylene selective hydrogenation catalyst is 70-240 m². 2 / g, more preferably 90-160m 2 / g.

[0023] According to a specific embodiment of the present invention, preferably, the pore volume of the phenylacetylene selective hydrogenation catalyst is 0.25-0.60 cm³. 3 / g, more preferably 0.35-0.50cm 3 / g.

[0024] This invention also provides a method for preparing the above-mentioned selective hydrogenation catalyst for phenylacetylene, which includes the following steps:

[0025] (1) After preparing a portion of the nickel salt into an aqueous solution, the carrier is impregnated, and after drying and calcination, a semi-finished catalyst is obtained;

[0026] (2) Dissolve the remaining nickel salt and zinc salt in an alcohol-water mixture, add the semi-finished catalyst obtained in step (1), perform hydrothermal treatment, and obtain the phenylacetylene selective hydrogenation catalyst by filtration, washing, drying and calcination.

[0027] According to a specific embodiment of the present invention, preferably, in the above preparation method, the impregnation in step (1) is an equal volume impregnation.

[0028] According to a specific embodiment of the present invention, preferably, in the above preparation method, the nickel salt includes one or more of nickel sulfate, nickel nitrate, nickel chloride, and nickel acetate, more preferably nickel nitrate and / or nickel acetate.

[0029] According to a specific embodiment of the present invention, preferably, in the above preparation method, the zinc salt includes one or more of zinc nitrate, zinc chloride, zinc sulfate, and zinc fluoroborate, or other soluble zinc salts.

[0030] According to a specific embodiment of the present invention, preferably, in the above preparation method, the volume ratio of alcohol to water in the alcohol-water mixture is 4-1:1, more preferably 2-1:1.

[0031] According to a specific embodiment of the present invention, preferably, in the above preparation method, the alcohol includes one or more of methanol, ethanol, and propanol.

[0032] According to a specific embodiment of the present invention, preferably, in the above preparation method, in steps (1) and (2), the drying temperature is 80-150℃ and the drying time is 2-8h.

[0033] According to a specific embodiment of the present invention, preferably, in the above preparation method, in steps (1) and (2), the calcination temperature is 300-450℃ and the calcination time is 3-8h.

[0034] According to a specific embodiment of the present invention, preferably, in the above preparation method, in step (2), the temperature of the hydrothermal treatment is 100-250℃, more preferably 120-200℃.

[0035] According to a specific embodiment of the present invention, preferably, in the above preparation method, the hydrothermal treatment time is 2-48 hours, more preferably 4-24 hours.

[0036] According to a specific embodiment of the present invention, the above preparation method includes the following specific steps:

[0037] (1) The nickel salt is dissolved in water and then impregnated on the carrier. The impregnated sample is dried and calcined to obtain a semi-finished catalyst. The nickel content in the semi-finished catalyst is 70wt%-95wt% of the total nickel content of the catalyst.

[0038] (2) Mix water and alcohol in a certain proportion until homogeneous, then dissolve nickel salt and zinc salt in the water and alcohol mixture and stir until completely dissolved;

[0039] (3) Add the semi-finished catalyst obtained in step (1) to the mixed solution prepared in step (2) and stir evenly. Then transfer it to a hydrothermal reactor for hydrothermal treatment. Filter and separate the resulting mixture. Wash, dry and calcine the obtained solid to obtain the phenylacetylene selective hydrogenation catalyst.

[0040] The hydrothermal treatment used in this invention is a commonly used hydrothermal treatment process condition for the preparation of alumina by hydrothermal method, as described in (Contemporary Petrochemicals, 2015, 9: 16-22).

[0041] This invention also provides a method for the selective hydrogenation of phenylacetylene in the presence of styrene. The method uses a hydrocarbon fraction containing phenylacetylene as feedstock, which is fed into a fixed-bed hydrogenation reactor. The hydrogenation reactor is equipped with the aforementioned selective hydrogenation catalyst for phenylacetylene. The hydrogenation process conditions are: reaction temperature 15-60°C, and volume hourly space velocity (VHSV) 0.1-3 h⁻¹. -1 The molar ratio of hydrogen to phenylacetylene is 1-10:1, and the reaction pressure is 0-1.0 MPa.

[0042] According to a specific embodiment of the present invention, preferably, the hydrogenation process conditions are: reaction temperature 20-45°C, and volume hourly space velocity (VHSV) 0.5-1.5 h⁻¹. -1 The molar ratio of hydrogen to phenylacetylene is 2-5:1, and the reaction pressure is 0.1-0.5 MPa.

[0043] This invention utilizes alumina as a support and employs hydrothermal processing to prepare a nanosheet-like Ni-Zn catalyst with a regularly morphological surface. This catalyst exhibits the advantage of being resistant to agglomeration after high-temperature reduction and also demonstrates excellent hydrogenation selectivity. This Ni-Zn catalyst with a regularly morphological nanosheet surface (a selective hydrogenation catalyst for phenylacetylene) not only effectively prevents the aggregation of Ni metal particles during high-temperature calcination and improves the dispersion of the active component, weakening the strong interaction between Ni and alumina, but also utilizes the active site isolation effect to allow Zn to act as a selective promoter, thus exhibiting high activity and high selectivity in the selective hydrogenation reaction of phenylacetylene, showing promising practical applications. The present invention provides a method for the selective hydrogenation of phenylacetylene in the presence of styrene, achieving selective hydrogenation of phenylacetylene under mild process conditions. Attached Figure Description

[0044] Figure 1 SEM image of the leaf-shaped aggregate structure catalyst obtained in Example 1;

[0045] Figure 2 The image shows the SEM image of the catalyst in Comparative Example 1. Detailed Implementation

[0046] To provide a clearer understanding of the technical features, objectives, and beneficial effects of this invention, the technical solution of this invention is described in detail below, but this should not be construed as limiting the scope of implementation of this invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0047] Styrene loss rate = (Styrene content in raw materials - Styrene content in product) * 100% / Styrene content in raw materials

[0048] Preparation Example 1

[0049] This preparation example provides a selective hydrogenation catalyst for phenylacetylene, and its preparation method is as follows:

[0050] (1) Nickel nitrate is dissolved in deionized water to prepare an impregnation solution. Then, the alumina support is immersed in the impregnation solution for impregnation. After impregnation, the support is dried at 110°C for 4 hours and then calcined at 380°C for 4 hours to obtain a semi-finished catalyst. The nickel in the semi-finished catalyst accounts for 85% of the total mass of nickel in the phenylacetylene selective hydrogenation catalyst.

[0051] (2) Dissolve nickel nitrate and zinc nitrate in 70 mL of a mixed solution of methanol and water (methanol to water volume ratio 7:3), then add the above semi-finished catalyst and stir evenly. Then transfer it to a high-pressure hydrothermal synthesis reactor and keep it at 150 °C for 12 h. After naturally cooling to room temperature, filter and wash the sample, dry it at 90 °C for 6 h and calcine it at 350 °C for 4 h to obtain the selective hydrogenation catalyst for phenylacetylene (catalyst 1). Based on the total mass of the catalyst being 100%, the Ni content in the catalyst is 12 wt% and the Zn content is 1.5 wt%.

[0052] The above catalyst was scanned by electron microscopy, such as... Figure 1 As shown, its surface is composed of nanosheets, with an average blade thickness of 10 nm, an average blade width of 598 nm, and an average blade length of 397 nm. The catalyst has a specific surface area of ​​105 m². 2 / g, pore volume is 0.41cm 3 / g.

[0053] Preparation Example 2

[0054] This preparation example provides a selective hydrogenation catalyst for phenylacetylene, and its preparation method is as follows:

[0055] (1) Nickel chloride is dissolved in deionized water to prepare an impregnation solution. Then, the alumina support is immersed in the impregnation solution for impregnation. After impregnation, the support is dried at 120°C for 3 hours and then calcined at 350°C for 4.5 hours to obtain a semi-finished catalyst. The nickel in the semi-finished catalyst accounts for 70% of the total mass of nickel in the phenylacetylene selective hydrogenation catalyst.

[0056] (2) Dissolve nickel nitrate and zinc sulfate in 80 mL of a mixture of anhydrous ethanol and water (volume ratio of anhydrous ethanol to water 3:2), then add the above semi-finished catalyst and stir evenly. Then transfer it to a high-pressure hydrothermal synthesis reactor and maintain it at 160℃ for 9 h. After naturally cooling to room temperature, filter and wash the sample, dry it at 130℃ for 3 h and calcine it at 340℃ for 6 h to obtain the selective hydrogenation catalyst for phenylacetylene (catalyst 2). Based on the total mass of the catalyst being 100%, the Ni content in the catalyst is 13.8 wt% and the Zn content is 0.8 wt%.

[0057] Electron microscopy revealed that the catalyst exhibited a nanosheet-like surface with an average blade thickness of 12 nm, an average blade width of 760 nm, and an average blade length of 412 nm. The catalyst had a specific surface area of ​​167 m². 2 / g, pore volume 0.55cm 3 / g.

[0058] Preparation Example 3

[0059] This preparation example provides a selective hydrogenation catalyst for phenylacetylene, and its preparation method is as follows:

[0060] (1) Nickel nitrate is dissolved in deionized water to prepare an impregnation solution. Then, the alumina support is immersed in the impregnation solution for impregnation. After impregnation, the support is dried at 140°C for 2 hours and then calcined at 310°C for 6 hours to obtain a semi-finished catalyst. The nickel in the semi-finished catalyst accounts for 80% of the total mass of nickel in the phenylacetylene selective hydrogenation catalyst.

[0061] (2) Dissolve nickel nitrate and zinc fluoroborate in 68 mL of a mixed solution of propanol and water (propanol to water volume ratio 4:1), then add the above semi-finished catalyst and stir evenly. Then transfer it to a high-pressure hydrothermal synthesis reactor and keep it at 170℃ for 7 h. After naturally cooling to room temperature, filter and wash the sample, dry it at 140℃ for 2 h and calcine it at 320℃ for 7 h to obtain the selective hydrogenation catalyst for phenylacetylene (catalyst 3). Based on the total mass of the catalyst being 100%, the Ni content in the catalyst is 14 wt% and the Zn content is 0.5 wt%.

[0062] Electron microscopy revealed that the catalyst exhibited a nanosheet-like surface with an average blade thickness of 7 nm, an average blade width of 485 nm, and an average blade length of 325 nm. The catalyst had a specific surface area of ​​10¹ m². 2 / g, pore volume is 0.39cm 3 / g.

[0063] Preparation Example 4

[0064] This preparation example provides a selective hydrogenation catalyst for phenylacetylene, and its preparation method is as follows:

[0065] (1) Nickel acetate is dissolved in deionized water to prepare an impregnation solution. Then, the alumina support is immersed in the impregnation solution for impregnation. After impregnation, the support is dried at 100°C for 5 hours and then calcined at 360°C for 4.5 hours to obtain a semi-finished catalyst. The nickel in the semi-finished catalyst accounts for 90% of the total mass of nickel in the phenylacetylene selective hydrogenation catalyst.

[0066] (2) Dissolve nickel nitrate and zinc nitrate in 77 mL of a mixture of anhydrous ethanol and water (volume ratio of anhydrous ethanol to water 3:1), then add the above semi-finished catalyst and stir evenly. Then transfer it to a high-pressure hydrothermal synthesis reactor and keep it at 190℃ for 3 h. After naturally cooling to room temperature, filter and wash the sample, dry it at 110℃ for 5 h and calcine it at 400℃ for 4 h to obtain the selective hydrogenation catalyst for phenylacetylene (catalyst 4). Based on the total mass of the catalyst being 100%, the Ni content in the catalyst is 11.5 wt% and the Zn content is 2 wt%.

[0067] Electron microscopy (EM) analysis of the catalyst C1 revealed that its surface consisted of nanosheets with an average thickness of 15 nm, an average width of 1437 nm, and an average length of 1192 nm. The specific surface area of ​​catalyst C1 was 132 m². 2 / g, pore volume is 0.47cm 3 / g.

[0068] Preparation Example 5

[0069] This preparation example provides a selective hydrogenation catalyst for phenylacetylene, and its preparation method is as follows:

[0070] (1) Nickel acetate is dissolved in deionized water to prepare an impregnation solution. Then, the alumina support is immersed in the impregnation solution for impregnation. After impregnation, the support is dried at 110°C for 3.5 h and then calcined at 450°C for 3 h to obtain a semi-finished catalyst. The nickel in the semi-finished catalyst accounts for 95% of the total mass of nickel in the phenylacetylene selective hydrogenation catalyst.

[0071] (2) Dissolve nickel nitrate and zinc fluoroborate in a 65 mL mixture of propanol and water (anhydrous ethanol to water volume ratio 2:1), then add the above semi-finished catalyst and stir evenly. Then transfer it to a high-pressure hydrothermal synthesis reactor and keep it at 140 °C for 18 h. After naturally cooling to room temperature, filter and wash the sample, dry it at 100 °C for 6 h and calcine it at 450 °C for 3 h to obtain the selective hydrogenation catalyst for phenylacetylene (catalyst 5). Based on the total mass of the catalyst being 100%, the Ni content in the catalyst is 10 wt% and the Zn content is 3 wt%.

[0072] Electron microscopy revealed that the catalyst exhibited a nanosheet-like surface with an average blade thickness of 17 nm, an average blade width of 1671 nm, and an average blade length of 1254 nm. The catalyst had a specific surface area of ​​89 m². 2 / g, pore volume 0.35cm 3 / g.

[0073] Preparation Comparative Example 1

[0074] This comparative example provides a comparative catalyst for the selective hydrogenation of phenylacetylene, and its preparation method is as follows:

[0075] 20 g of a composite support with an alumina to silica weight ratio of 20:1 was weighed and added to a mixed solution of nickel nitrate, lanthanum nitrate, and zinc nitrate. The solution was impregnated by an equal-volume impregnation method, dried at 120°C for 6 hours, and calcined at 400°C for 8 hours to obtain a nickel-based catalyst (catalyst D1) with a nickel content of 12 wt% of the support weight, a lanthanum content of 0.8 wt%, and a zinc content of 1.5 wt%.

[0076] The catalyst was scanned by electron microscopy, such as... Figure 2 As shown, by Figure 2 It can be seen that the catalyst surface exists in the form of irregular spherical aggregates, which are prone to agglomeration during high-temperature reduction or long-term evaluation.

[0077] Preparation Comparative Example 2

[0078] This comparative example provides a comparative catalyst for the selective hydrogenation of phenylacetylene, and its preparation method is as follows:

[0079] Nickel nitrate and zinc fluoroborate were dissolved in water to prepare an impregnation solution. The alumina support was then immersed in this solution using an equal-volume impregnation method. The impregnated sample was dried at 140℃ for 2 hours and calcined at 320℃ for 7 hours to obtain the catalyst (catalyst D2). Based on a total catalyst mass of 100%, the catalyst contained 14 wt% Ni and 0.5 wt% Zn. The specific surface area of ​​this catalyst was 10⁸ m². 2 / g, pore volume 0.4cm 3 / g.

[0080] Preparation Comparative Example 3

[0081] This comparative example provides a comparative catalyst for the selective hydrogenation of phenylacetylene, and its preparation method is as follows:

[0082] 7.5g of aluminum nitrate and 6g of urea were added to 70mL of deionized water and magnetically stirred for 20 minutes to obtain a colorless and transparent solution. The solution was then transferred to a high-pressure reactor, and hydrogen gas was introduced to purge the air from the reactor. The hydrogen pressure in the reactor was then set to 0.5MPa, and the reactor was sealed. The reactor was heated to 120℃ and reacted for 24 hours. After the reaction, the reactor was allowed to cool naturally to room temperature, the gas inside was released, the reactor was opened, and the reaction slurry was collected. The reaction slurry was filtered, and the filtrate was washed three times with deionized water. The filtrate was then transferred to an 80℃ oven and dried for 8 hours to obtain the γ-alumina precursor – boehmite monohydrate. Finally, the boehmite monohydrate was calcined in a muffle furnace, heated from room temperature to 550℃ at a rate of 2℃ / min, held for 6 hours, and then naturally cooled to obtain leaf-shaped nano-γ-alumina. The specific surface area of ​​the obtained γ-alumina was 267 m². 2 / g, with an average pore size of 6.7nm.

[0083] Then, nickel acetate and zinc nitrate were dissolved in deionized water to prepare an impregnation solution, which was then placed on the aforementioned leaf-shaped nano-γ-alumina support for impregnation. The impregnated sample was dried at 110℃ for 5 h and then calcined at 360℃ for 4.5 h to obtain the catalyst (catalyst D3). Based on the total mass of the catalyst (100%), the catalyst contained 11.5 wt% Ni and 2 wt% Zn.

[0084] Preparation Comparative Example 4

[0085] This comparative example provides a comparative catalyst for the selective hydrogenation of phenylacetylene, and its preparation method is as follows:

[0086] Nickel nitrate and zinc fluoroborate were dissolved in water to prepare an impregnation solution. The alumina support was then immersed in the impregnation solution using an equal-volume impregnation method. The impregnated sample was dried at 110℃ for 3.5 h and calcined at 450℃ for 3 h to obtain the catalyst (catalyst D4). Based on the total mass of the catalyst (100%), the catalyst contained 10 wt% Ni and 3 wt% Zn. The specific surface area of ​​this catalyst was 85 m². 2 / g, pore volume is 0.33cm 3 / g.

[0087] Catalytic performance evaluation

[0088] Raw material and product composition analysis methods: Agilent 7890B gas chromatograph was used to analyze the raw materials and composition.

[0089] Reaction process flow: The C8 fraction is metered through a metering tube and then pumped to the reaction pressure by a plunger pump. After preheating, it is mixed with hydrogen gas at a constant pressure and enters the catalyst bed from the top / bottom of the reactor. The reaction products are cooled and then enter a gas-liquid separator for separation. The separated H2 is depressurized and metered by a wet flow meter before being vented. The liquid is discharged into the product storage tank, and the content of ST, PA and other components is analyzed by an Agilent 7890B gas chromatograph.

[0090] Example 1

[0091] Catalyst 1 was loaded into a 500 mL fixed-bed reactor and the catalyst was first reduced and activated. The catalyst was maintained at a pressure of 2.5 MPa, a bed temperature of 350 °C, and a hydrogen flow rate of 120 L / h for 10 h. Then the temperature was lowered to 30 °C to complete the activation of the catalyst.

[0092] After activation, using 31.47 wt% styrene and 0.87 wt% phenylacetylene from cracked gasoline C8 fraction as feedstock, a bottom-feed method was adopted, with an inlet temperature of 30°C, a reaction pressure of 0.3 MPa, and a liquid hourly space velocity of 1.0 h⁻¹. -1 The product was operated for 300 hours under a hydrogen / phenylacetylene molar ratio of 4. The styrene and phenylacetylene content in the product was sampled and analyzed every 8 hours. The average reaction results were: 0 ppm phenylacetylene and -1.2% styrene loss.

[0093] The average results after 700 hours of operation were: 5 ppm phenylacetylene and -0.5% styrene loss, indicating that the catalyst has excellent selectivity and stability.

[0094] Example 2

[0095] Catalyst 2 was loaded into a 100 mL fixed-bed reactor and the catalyst was first reduced and activated. The catalyst was maintained at a pressure of 2.8 MPa, a bed temperature of 300 °C, and a hydrogen flow rate of 30 L / h for 8 h. Then the temperature was lowered to 27 °C to complete the activation of the catalyst.

[0096] After activation, using 33.56 wt% styrene and 0.75 wt% phenylacetylene from cracked gasoline C8 fraction as feedstock, a bottom-feed method was adopted, with an inlet temperature of 27°C, a reaction pressure of 0.5 MPa, and a liquid hourly space velocity of 0.8 h⁻¹. -1 The product was operated for 300 hours under a hydrogen / phenylacetylene molar ratio of 5. The styrene and phenylacetylene content in the product was sampled and analyzed every 8 hours. The average reaction results were: 4 ppm phenylacetylene and -0.5% styrene loss.

[0097] Example 3

[0098] Catalyst 3 was loaded into a 250 mL fixed-bed reactor and the catalyst was first reduced and activated. The catalyst was maintained at a pressure of 2.0 MPa, a bed temperature of 250 °C, and a hydrogen flow rate of 80 L / h for 6 h. Then the temperature was lowered to 32 °C to complete the activation of the catalyst.

[0099] After activation, using 32.17 wt% styrene and 0.59 wt% phenylacetylene from cracked gasoline C8 fraction as feedstock, a top-feed method was adopted, with an inlet temperature of 32°C, a reaction pressure of 0.1 MPa, and a liquid hourly space velocity of 1.2 h⁻¹. -1 The product was operated for 300 hours under a hydrogen / phenylacetylene molar ratio of 8. The styrene and phenylacetylene content in the product was sampled and analyzed every 8 hours. The average reaction results were: phenylacetylene 1 ppm and styrene loss rate 0.1%.

[0100] Example 4

[0101] Catalyst 4 was loaded into a 500 mL fixed-bed reactor and first underwent reduction and activation. The catalyst was maintained at a pressure of 2.0 MPa, a bed temperature of 320 °C, and a hydrogen flow rate of 150 L / h for 12 h. Then, the temperature was lowered to 24 °C to complete the activation of the catalyst.

[0102] After activation, using 32.78 wt% styrene and 0.81 wt% phenylacetylene from cracked gasoline C8 fraction as feedstock, a bottom-feed method was adopted, with an inlet temperature of 24 °C, a reaction pressure of 0.4 MPa, and a liquid hourly space velocity of 0.5 h⁻¹. -1 The product was operated for 300 hours under a hydrogen / phenylacetylene molar ratio of 2. The styrene and phenylacetylene content in the product was sampled and analyzed every 8 hours. The average reaction results were: 8 ppm phenylacetylene and 0.8% styrene loss.

[0103] Example 5

[0104] Catalyst 5 was loaded into a 250 mL fixed-bed reactor and the catalyst was first reduced and activated. The catalyst was maintained at a pressure of 1.8 MPa, a bed temperature of 280 °C, and a hydrogen flow rate of 70 L / h for 12 h. Then the temperature was lowered to 24 °C to complete the activation of the catalyst.

[0105] After activation, using 33.14 wt% styrene and 0.64 wt% phenylacetylene from cracked gasoline C8 fraction as feedstock, a bottom-feed method was adopted, with an inlet temperature of 40°C, a reaction pressure of 0.7 MPa, and a liquid hourly space velocity of 1.5 h⁻¹. -1 The product was operated for 300 hours under a hydrogen / phenylacetylene molar ratio of 10. The styrene and phenylacetylene content in the product was sampled and analyzed every 8 hours. The average reaction results were: 0 ppm phenylacetylene and 0.3% styrene loss.

[0106] Comparative Example 1

[0107] The catalyst reduction and activation treatment method and evaluation process conditions are the same as in Example 1, except that catalyst D1 is used. The average reaction results are: 32 ppm phenylacetylene and 0.2% styrene loss.

[0108] Average results after 700 hours of operation: 65 ppm phenylacetylene and 1.1% styrene loss.

[0109] Comparative Example 2

[0110] The catalyst reduction and activation treatment method and evaluation process conditions are the same as in Example 3, except that catalyst D2 is used. The average reaction results are: 21 ppm of phenylacetylene and 0.8% loss of styrene.

[0111] Comparative Example 3

[0112] The catalyst reduction and activation treatment method and evaluation process conditions are the same as in Example 4, except that catalyst D3 is used. The average reaction results are: 47 ppm phenylacetylene and 0.5% styrene loss.

[0113] Comparative Example 4

[0114] The catalyst reduction and activation treatment method and evaluation process conditions are the same as in Example 5, except that catalyst D4 is used. The average reaction results are: 13 ppm of phenylacetylene and 1.1% loss of styrene.

[0115] Data analysis from the examples and comparative examples shows that, by using the hydrogenation method of the present invention and the catalyst with the nanosheet morphology of the present invention, the content of phenylacetylene in the hydrogenation product can reach 0 ppm and styrene increases, which can meet the industrial application conditions for subsequent styrene extraction.

[0116] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A selective hydrogenation catalyst for phenylacetylene, wherein, based on 100% by mass of the selective hydrogenation catalyst for phenylacetylene, its composition comprises 8-18% nickel, 0.5-4% zinc, and the balance being a support; in, Some of the nickel is loaded onto the support by impregnation, and the remaining nickel and zinc are distributed on the surface of the support by hydrothermal treatment. The surface of the phenylacetylene selective hydrogenation catalyst has a plate-like structure. The phenylacetylene selective hydrogenation catalyst is prepared by a method including the following steps: (1) After preparing a portion of the nickel salt into an aqueous solution, the carrier is impregnated, and after drying and calcination, a semi-finished catalyst is obtained; (2) Dissolve the remaining nickel salt and zinc salt in an alcohol-water mixture, add the semi-finished catalyst obtained in step (1), perform hydrothermal treatment, and then filter, wash, dry and calcinate to obtain the phenylacetylene selective hydrogenation catalyst. In steps (1) and (2), the roasting temperature is 300-450℃ and the roasting time is 3-8h; In step (2), the temperature of the hydrothermal treatment is 100-250℃ and the time of the hydrothermal treatment is 2-48h.

2. The selective hydrogenation catalyst for phenylacetylene according to claim 1, wherein, The selective hydrogenation catalyst for phenylacetylene comprises 10-15% nickel and 1-2% zinc.

3. The selective hydrogenation catalyst for phenylacetylene according to claim 1, wherein, The portion of nickel impregnated and supported on the carrier accounts for 70-95 wt% of the total nickel content in the phenylacetylene selective hydrogenation catalyst.

4. The selective hydrogenation catalyst for phenylacetylene according to claim 1, wherein, The carrier includes aluminum oxide.

5. The selective hydrogenation catalyst for phenylacetylene according to claim 1, wherein, The thickness of the sheet-like structure is 5-20 nm, and the width and length are both 300-3000 nm.

6. The selective hydrogenation catalyst for phenylacetylene according to claim 5, wherein, The thickness of the sheet-like structure is 8-15 nm, and the width and length are both 500-1500 nm.

7. The selective hydrogenation catalyst for phenylacetylene according to claim 1, wherein, The specific surface area of ​​the selective hydrogenation catalyst for phenylacetylene is 70-240 m². 2 / g.

8. The selective hydrogenation catalyst for phenylacetylene according to claim 7, wherein, The specific surface area of ​​the selective hydrogenation catalyst for phenylacetylene is 90-160 m². 2 / g.

9. The selective hydrogenation catalyst for phenylacetylene according to claim 1, wherein, The pore volume of the selective hydrogenation catalyst for phenylacetylene is 0.25-0.60 cm³. 3 / g.

10. The selective hydrogenation catalyst for phenylacetylene according to claim 9, wherein, The pore volume of the selective hydrogenation catalyst for phenylacetylene is 0.35-0.50 cm³. 3 / g.

11. A method for preparing the selective hydrogenation catalyst for phenylacetylene according to any one of claims 1-10, comprising the following steps: (1) After preparing a portion of the nickel salt into an aqueous solution, the carrier is impregnated, and after drying and calcination, a semi-finished catalyst is obtained; (2) Dissolve the remaining nickel salt and zinc salt in an alcohol-water mixture, add the semi-finished catalyst obtained in step (1), perform hydrothermal treatment, and obtain the phenylacetylene selective hydrogenation catalyst by filtration, washing, drying and calcination.

12. The preparation method according to claim 11, wherein, The impregnation in step (1) is an equal-volume impregnation.

13. The preparation method according to claim 11 or 12, wherein, The nickel salt includes one or more of nickel sulfate, nickel nitrate, nickel chloride, and nickel acetate.

14. The preparation method according to claim 13, wherein, The nickel salt is nickel nitrate and / or nickel acetate.

15. The preparation method according to claim 11 or 12, wherein, The zinc salt includes one or more of zinc nitrate, zinc chloride, zinc sulfate, and zinc fluoroborate.

16. The preparation method according to claim 11, wherein, The volume ratio of alcohol to water in the alcohol-water mixture is 4-1:

1.

17. The preparation method according to claim 16, wherein, The volume ratio of alcohol to water in the alcohol-water mixture is 2-1:

1.

18. The preparation method according to claim 16 or 17, wherein, The alcohol includes one or more of methanol, ethanol, and propanol.

19. The preparation method according to claim 11 or 12, wherein, In steps (1) and (2), the drying temperature is 80-150℃ and the drying time is 2-8h.

20. The preparation method according to claim 11 or 12, wherein, In step (2), the temperature of the hydrothermal treatment is 120-200℃ and the time of the hydrothermal treatment is 4-24h.

21. A method for selective hydrogenation of phenylacetylene in the presence of styrene, wherein a hydrocarbon fraction containing phenylacetylene is fed into a fixed-bed hydrogenation reactor, the hydrogenation reactor being loaded with the selective hydrogenation catalyst of any one of claims 1-10, and the hydrogenation process conditions being: reaction temperature 15-60°C, volume hourly space velocity (VHSV) 0.1-3 h⁻¹. -1 The molar ratio of hydrogen to phenylacetylene is 1-10:1, and the reaction pressure is 0-1.0 MPa.

22. The selective hydrogenation method for phenylacetylene according to claim 21, wherein, The hydrogenation process conditions are: reaction temperature 20-45℃, volume hourly space velocity (VHSV) 0.5-1.5 h⁻¹. -1 The molar ratio of hydrogen to phenylacetylene is 2-5:1, and the reaction pressure is 0.1-0.5 MPa.

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