A catalyst for selective hydrogenation of phenylacetylene in the presence of styrene and a preparation method thereof

Abstract

This invention discloses a selective hydrogenation catalyst for phenylacetylene in the presence of styrene and its preparation method. The catalyst is a Ni-Zn catalyst with a regular surface morphology and a nano-leaf-like structure; the leaf thickness is 5-20 nm, the leaf width and length are 300-3000 nm, and the specific surface area is 70-240 m². 2 / g, pore volume is 0.25~0.60cm³ 3 / g. The nanosheet morphology on the surface of this catalyst 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 the active site isolation effect allows Zn to act as a selective promoter to improve the selectivity of styrene. Thus, it exhibits high activity and high selectivity in the selective hydrogenation reaction of phenylacetylene. When used for the selective hydrogenation of C8 fraction to remove phenylacetylene, this catalyst has the advantage of not easily agglomerating after high-temperature reduction, and at the same time has excellent hydrogenation selectivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of carbon eight hydrogenation catalyst, in particular to a selective phenylacetylene hydrogenation catalyst in the presence of styrene and a preparation method thereof. BACKGROUND

[0002] Styrene (ST) is an important monomer for producing polystyrene, ABS resin, styrene-butadiene rubber, etc. Ethylbenzene dehydrogenation is the main preparation method, but it has the disadvantage of high production cost. In recent years, with the large-scale production of ethylene, extraction of styrene from the by-product carbon eight fraction of cracking ethylene has become a new and attractive way to increase the production of styrene.

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

[0004] The scheme for recovering styrene from cracking gasoline currently uses extractive distillation, but this part of the cracking carbon eight fraction contains 4000-15000 μg·g -1 of phenylacetylene (PA), and ST and PA have similar chemical structures, and the interaction between the two and the extractive distillation solvent is also similar, so the existing extractive distillation process conditions cannot achieve effective separation of ST and PA. The presence of these phenylacetylene not only increases the catalyst consumption during styrene anion polymerization, but also affects the chain length and polymerization speed, and also affects the color, odor and overall performance of the polymerization product. Therefore, before extracting styrene from ethylene cracking carbon eight, selective hydrogenation of phenylacetylene must be carried out, and the carbon eight fraction contains 25-45% of styrene, so when hydrogenating phenylacetylene, the hydrogenation loss of styrene should also be minimized. The content of phenylacetylene in the hydrogenation product and the loss of styrene determine the efficiency of the process for recovering styrene from cracking gasoline carbon eight fraction.

[0005] At present, more than 80% of the styrene selective hydrogenation catalysts used in the industrial application of styrene extraction devices in China are nickel-based catalysts. The preparation method adopts the conventional equal-volume impregnation method. Before use, it is generally necessary to carry out high-temperature activation in flowing hydrogen to reduce NiO to metal Ni particles, which may cause the agglomeration and sintering of Ni particles, resulting in poor stability and selectivity. Therefore, researchers have improved the selective hydrogenation performance of supported Ni-based catalysts by adding additives and improving the preparation method. To solve this problem, existing patents and literature report that on the one hand, the support is modified to achieve the purpose of adjusting the interaction between the support and the active component; on the other hand, additives such as Zn, Cu, Mg, Co or Sn are added to adjust the geometry and electronic structure of the Ni active sites to improve the selective hydrogenation performance of the catalyst. Although it has a certain effect on improving the selectivity of styrene, there is still room for improvement, and it is difficult to achieve high activity and high selectivity.

[0006] As disclosed in Chinese patent document CN107952446A, a nickel catalyst for selective hydrogenation of phenylacetylene in carbon octane fractions comprises the following components by weight percentage: (a) 5-30% of metallic nickel or its oxide; (b) 0.01-20% of at least one element selected from molybdenum or tungsten or its oxide; (c) 0.01-10.0% of at least one element selected from rare earth or its oxide; (d) 0.01-2.0% of at least one element selected from IA or IIA in the periodic table or its oxide; (e) 0-15% of at least one element selected from silicon, phosphorus, boron or fluorine or its oxide; (f) 0-10% of at least one element selected from IVB in the periodic table or its oxide; (g) the balance of alumina.

[0007] Chinese patent document CN102649066A discloses a catalyst for selective hydrogenation of phenylacetylene in the presence of styrene, which comprises the following components by weight percentage: 2-50.0% of metallic nickel or its oxide; 0.05-10% of at least one element selected from rare earth or its oxide; 40-88% of a carrier selected from at least one of alumina, silicon oxide or molecular sieve, the specific surface area of the carrier being 60-300 m 2 / g.

[0008] Chinese patent document CN102649065A relates to a catalyst for selective hydrogenation of phenylacetylene in the presence of styrene, comprising the following components in percentage by weight: (a) 2-50 parts of metallic nickel or its oxide; (b) 0.05-10 parts of at least one element selected from rare earths or its oxide; (c) 0.01-5 parts of at least one element selected from IA and IIA of the periodic table of elements or its oxide; (d) 49-85 parts of a carrier; wherein the carrier is selected from alumina, the average pore size of the carrier is 3-30 nm, the pore volume is 0.4-1.5 ml / g, and the specific surface area is 100-450 m2 / g. The technical solution can be used in industrial production of hydrogenation to remove phenylacetylene in the presence of styrene.

[0009] Chinese patent document CN107413344A discloses a preparation method of a limited structure hexahedral morphology nano nickel-based catalyst. First, an organic carbon chain intercalated nickel aluminum hydrotalcite precursor is synthesized, and a limited structure nickel-based catalyst is prepared by using the explosive in-situ uniform reduction of the organic carbon source. The catalyst has the structural characteristics of high crystallinity and small size hexahedral morphology metal nickel nanoparticles limited in Ni(Al)Ox / C.

[0010] Chinese patent document CN114249300A provides an application of a specific microstructure alumina supported Ni catalyst in plasma catalytic dry reforming of methane to prepare synthesis gas. Methane and carbon dioxide are used as raw materials, Ni / Al2O3 is used as a catalyst, and the reaction is carried out in a plasma reactor to prepare synthesis gas under mild conditions. Al2O3 is a mixture of one or more of nanosheet Al2O3, feather-like Al2O3, ball-flower-like Al2O3, and rod-like Al2O3 with different microstructures. The above different structure carriers directly affect the dispersion, stability and discharge capacitance of Ni particles, thereby affecting the catalytic performance of Ni / Al2O3 under mild conditions.

[0011] Chinese patent document CN112705209A provides a reforming hydrogen catalyst, a preparation method and application thereof. The catalyst comprises the following components in percentage by mass: 3-10% of nickel element, 50-60% of magnesium element, 0.6-0.7% of lanthanum element, and the rest is oxygen element; the sum of the mass percentages of the above elements is 100%. The catalyst is prepared by a hydrothermal method and a coprecipitation method. Nickel and magnesium form a Ni x Mg y O solid solution, which has very superior anti-coking and anti-carbon deposition performance; on this basis, through the modification of a trace amount of lanthanum element, it shows good catalytic activity in a low temperature environment.

[0012] Chinese patent document CN108212134A discloses a silicon-containing boehmite catalyst carrier and a preparation method thereof. The catalyst carrier is a porous material, the porous material is a porous silicon-aluminum material, the porous silicon-aluminum is in a nanosheet shape, the content of silicon oxide is 1-20wt%, the specific surface area is 800-1000m 2 / g, the pore volume is 1.7-4.0cm 3 / g, and the most probable pore diameter is 2-30nm. The scheme can prepare a silicon-containing boehmite catalyst carrier with a nanosheet structure, a large specific surface area, and a large pore volume by regulating the mass ratio of sodium metaaluminate, aluminum sulfate, and water glass according to the contents of aluminum oxide and silicon oxide to control the reaction endpoint.

[0013] Chinese patent document CN102649063A discloses a catalyst for selective hydrogenation of phenylacetylene in the presence of styrene, which comprises the following components in percentage by weight: (a) 2-50.0% of metal nickel or its oxide; (b) 0.05-10% of at least one element selected from rare earth or its oxide; (c) 0.01-6% of at least one element selected from IB, IIB, VIB, or VIIB of the periodic table or its oxide; and (d) 49-85% of a carrier. The carrier is selected from a composite carrier of alumina and silica, and the weight ratio of alumina to silica is 0.01-100:1. The catalyst can be used in industrial production of hydrogenation of phenylacetylene in the presence of styrene. Although the scheme improves the activity and selectivity of selective hydrogenation of phenylacetylene in the presence of styrene, the addition of silica inevitably affects the acidity of the carrier and then affects the running stability of the catalyst.

[0014] Chinese patent document CN1160284C discloses a method for hydrogenating phenylacetylene in a medium containing styrene by means of a catalyst, which is a nickel catalyst with a nickel content of 10-25wt% supported on a carrier material, and the molar ratio of hydrogen to phenylacetylene is 1-10. SUMMARY

[0015] In view of the problems in the prior art and the direction for improvement, the present application provides a catalyst for selective hydrogenation of phenylacetylene in the presence of styrene to solve the technical problem of low hydrogenation rate of phenylacetylene and high loss rate of styrene (i.e., high activity and high selectivity cannot be achieved) in the process of selective hydrogenation of phenylacetylene in the presence of styrene in the prior art.

[0016] To achieve the above-mentioned purpose, the present application provides a catalyst for selective hydrogenation of phenylacetylene in the presence of styrene, wherein the carrier is alumina, and the catalyst for selective hydrogenation of phenylacetylene is a Ni-Zn catalyst with a regular nanoleaf structure.

[0017] The average thickness of the leaf is 5-20 nm, the average width of the leaf is 300-3000 nm, the average length of the leaf is 300-3000 nm, the specific surface area is 70-240 m 2 / g, and the pore volume is 0.25-0.60 cm 3 / g.

[0018] The alumina carrier in the selective hydrogenation catalyst for phenylacetylene provided by the application is not limited, and commercially available alumina or alumina prepared by an existing preparation method can be used.

[0019] Optionally, the average thickness of the leaf in the selective hydrogenation catalyst for phenylacetylene in the presence of styrene provided by the application is 8-15 nm, the average width of the leaf is 500-1500 nm, the average length of the leaf is 500-1500 nm, the specific surface area is 90-160 m 2 / g, and the pore volume is 0.35-0.50 cm 3 / g.

[0020] Optionally, the content of Ni is 8wt%-18wt%, preferably 10wt%-15wt%, and the content of Zn is 0.5wt%-4wt%, preferably 1wt%-2wt%, based on the total mass of the selective hydrogenation catalyst for phenylacetylene.

[0021] The application further provides a preparation method of the selective hydrogenation catalyst for phenylacetylene in the presence of styrene.

[0022] 1) The alumina carrier is immersed in a nickel salt aqueous solution, and then dried and calcined to obtain a semi-finished catalyst; the content of nickel in the semi-finished catalyst is 70wt%-95wt% of the content of nickel in the selective hydrogenation catalyst for phenylacetylene.

[0023] 2) The nickel salt and the zinc salt are dissolved in an alcohol-water mixed solution, and then the semi-finished catalyst is added and stirred uniformly, and then a solid obtained by hydrothermal reaction is washed, dried and calcined to obtain the selective hydrogenation catalyst for phenylacetylene in the presence of styrene.

[0024] Optionally, in the preparation method of the selective hydrogenation catalyst for phenylacetylene in the presence of styrene, the volume ratio of the alcohol to water in the mixed solution of alcohol and water is 4-1:1, preferably 2-1:1; the alcohol is at least one of methanol, anhydrous ethanol and propanol, and the anhydrous ethanol is preferred.

[0025] Optionally, in the preparation method of the selective hydrogenation catalyst for phenylacetylene in the presence of styrene, the zinc salt is a soluble zinc salt, preferably at least one of zinc nitrate, zinc chloride, zinc fluoroborate and zinc sulfate, and more preferably zinc nitrate; the nickel salt is at least one of nickel sulfate, nickel nitrate, nickel chloride and nickel acetate, and preferably nickel nitrate and / or nickel acetate.

[0026] Optionally, in the preparation method of the selective hydrogenation catalyst for phenylacetylene in the presence of styrene, the process conditions of the hydrothermal reaction can be conventional in the industry, such as the parameters disclosed in (Contemporary Petroleum Chemical Industry, 2015, 9: 16-22). The recommended temperature of the hydrothermal reaction is 100-250°C, and the time is 2-48h; preferably, the temperature of the hydrothermal reaction is 120-200°C, and the time is 4-24h.

[0027] Optionally, in the preparation method of the selective hydrogenation catalyst for phenylacetylene in the presence of styrene, the parameters of drying and calcination in steps 1) and 2) are not specifically limited and can be conventional in the industry. The recommended temperature of the drying is 80-150°C, the recommended temperature of the calcination is 300-500°C, and the recommended time of the calcination is 2-8h.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] 1. The selective hydrogenation catalyst for phenylacetylene in the presence of styrene provided by the present application uses alumina as a carrier, and a Ni-Zn catalyst with regular nanosheet morphology is formed on the surface thereof through a hydrothermal reaction. The catalyst has the advantages of not being easy to agglomerate after high-temperature reduction and excellent hydrogenation selectivity when used for selective hydrogenation of benzene acetylene in carbon eight fraction.

[0030] 2. The selective hydrogenation catalyst for phenylacetylene in the presence of styrene provided by the present application has a nanosheet morphology on the surface, which can effectively prevent the aggregation of Ni metal particles during high-temperature calcination, improve the dispersion of active components, weaken the strong interaction between Ni and alumina, and improve the selectivity of styrene by using Zn as a selective promoter through active site isolation effect, thereby showing high activity and high selectivity in the selective hydrogenation reaction of phenylacetylene and having practical application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1This is a SEM image of the catalyst prepared in Example 1 of the present invention;

[0032] Figure 2 This is a SEM image of the catalyst prepared in Comparative Example 1 of this invention. Detailed Implementation

[0033] The following provides a detailed description of the embodiments of the present invention: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and processes. However, the scope of protection of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0034] Example 1

[0035] This embodiment provides a selective hydrogenation catalyst for phenylacetylene, the preparation method of which is as follows:

[0036] (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.

[0037] (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, dry the sample at 90 °C for 6 h and calcine at 500 °C for 4 h to obtain the catalyst. 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%.

[0038] 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.

[0039] Example 2

[0040] This embodiment provides a selective hydrogenation catalyst for phenylacetylene, the preparation method of which is as follows:

[0041] (1) The nickel chloride is dissolved in deionized water to form an impregnation solution, and then the carrier alumina is put into the impregnation solution for impregnation. The impregnated carrier is dried at 120℃ for 3h and then calcined at 350℃ for 4.5h 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;

[0042] (2) The nickel nitrate and zinc sulfate are dissolved in 80mL of a mixed solution of anhydrous ethanol and water (volume ratio of anhydrous ethanol to water 3:2), and then the semi-finished catalyst is added and stirred uniformly. Subsequently, it is transferred into a high-pressure hydrothermal synthesis kettle and kept at 160℃ for 9h. After natural cooling to room temperature, the sample is dried at 130℃ for 3h and calcined at 340℃ for 6h to obtain the catalyst. The Ni content in the catalyst is 13.8wt% and the Zn content is 0.8wt% based on the total mass of the catalyst being 100%.

[0043] The above catalyst is scanned by electron microscopy, and the surface is nanosheet-shaped. The average thickness of the leaf is 12nm, the average width of the leaf is 760nm, and the average length of the leaf is 412nm. The specific surface area of the catalyst is 167m 2 / g, and the pore volume is 0.55cm 3 / g.

[0044] Example 3

[0045] The present embodiment provides a phenylacetylene selective hydrogenation catalyst, and the preparation method is as follows:

[0046] (1) The nickel nitrate is dissolved in deionized water to form an impregnation solution, and then the carrier alumina is put into the impregnation solution for impregnation. The impregnated carrier is dried at 130℃ for 2.5h and then calcined at 330℃ for 5h to obtain a semi-finished catalyst. The nickel in the semi-finished catalyst accounts for 75% of the total mass of nickel in the phenylacetylene selective hydrogenation catalyst;

[0047] (2) The nickel nitrate and zinc chloride are dissolved in 75mL of a mixed solution of anhydrous ethanol and water (volume ratio of anhydrous ethanol to water 1:1), and then the semi-finished catalyst is added and stirred uniformly. Subsequently, it is transferred into a high-pressure hydrothermal synthesis kettle and kept at 170℃ for 7h. After natural cooling to room temperature, the sample is dried at 90℃ for 8h and calcined at 350℃ for 4h to obtain the catalyst. The Ni content in the catalyst is 12.5wt% and the Zn content is 1.5wt% based on the total mass of the catalyst being 100%.

[0048] The above catalyst is scanned by electron microscopy, and the surface is nanosheet-shaped. The average thickness of the leaf is 14nm, the average width of the leaf is 974nm, and the average length of the leaf is 816nm. The specific surface area of the catalyst is 119m 2 / g, and the pore volume is 0.43cm 3 / g.

[0049] Example 4

[0050] The present example provides a phenylacetylene selective hydrogenation catalyst, and the preparation method is as follows:

[0051] (1) Dissolve nickel nitrate in deionized water to prepare an impregnation solution, then put the carrier alumina into the impregnation solution for impregnation, and then dry the impregnated carrier at 140°C for 2h, and then calcine it at 310°C for 6h to obtain a semi-finished catalyst; and the nickel in the semi-finished catalyst accounts for 80% of the total mass of nickel in the phenylacetylene selective hydrogenation catalyst;

[0052] (2) Dissolve nickel nitrate and zinc fluoroborate in 68mL of a mixed solution of propanol and water (volume ratio of propanol to water is 4:1), then add the above semi-finished catalyst and stir uniformly, then transfer it to a high-pressure hydrothermal synthesis kettle and keep it at 170°C for 7h, then naturally cool it to room temperature, then dry the sample at 140°C for 2h and calcine it at 320°C for 7h to obtain the catalyst; and the Ni content in the catalyst is 14wt%, and the Zn content is 0.5wt% based on the total mass of the catalyst being 100%.

[0053] The above catalyst is scanned by electron microscopy, and the surface is nanosheet-shaped, with an average leaf thickness of 7nm, an average leaf width of 485nm, and an average length of 325nm. The specific surface area of the catalyst is 101m 2 / g, and the pore volume is 0.39cm 3 / g.

[0054] Example 5

[0055] The present example provides a phenylacetylene selective hydrogenation catalyst, and the preparation method is as follows:

[0056] (1) Dissolve nickel nitrate in deionized water to prepare an impregnation solution, then put the carrier alumina into the impregnation solution for impregnation, and then dry the impregnated carrier at 140°C for 2h, and then calcine it at 310°C for 6h to obtain a semi-finished catalyst; and the nickel in the semi-finished catalyst accounts for 80% of the total mass of nickel in the phenylacetylene selective hydrogenation catalyst;

[0057] (2) Dissolve nickel nitrate and zinc fluoroborate in 68mL of a mixed solution of propanol and water (volume ratio of propanol to water is 4:1), then add the above semi-finished catalyst and stir uniformly, then transfer it to a high-pressure hydrothermal synthesis kettle and keep it at 170°C for 7h, then naturally cool it to room temperature, then dry the sample at 140°C for 2h and calcine it at 320°C for 7h to obtain the catalyst; and the Ni content in the catalyst is 14wt%, and the Zn content is 0.5wt% based on the total mass of the catalyst being 100%.

[0058] The catalyst C1 is scanned by electron microscope, and the surface is nanosheet, the average thickness of the leaf is 15 nm, the average width of the leaf is 1437 nm, and the average length of the leaf is 1192 nm. The specific surface area of the catalyst C1 is 132 m 2 / g, the pore volume is 0.47 cm 3 / g.

[0059] Example 6

[0060] The embodiment provides a phenylacetylene selective hydrogenation catalyst, and a preparation method thereof.

[0061] (1) The nickel acetate is dissolved in deionized water to form an impregnation solution, and then the carrier alumina is put into the impregnation solution for impregnation. The impregnated carrier is dried at 110 DEG C for 3.5 h and calcined at 450 DEG 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 the nickel in the phenylacetylene selective hydrogenation catalyst.

[0062] (2) The nickel nitrate and zinc fluoroborate are dissolved in 65 mL of a mixed solution of propanol and water (the volume ratio of anhydrous ethanol to water is 2:1), and then the semi-finished catalyst is added and stirred uniformly. Subsequently, the mixture is transferred into a high-pressure hydrothermal synthesis kettle and kept at 140 DEG C for 18 h. After natural cooling to room temperature, the sample is dried at 100 DEG C for 6 h and calcined at 450 DEG C for 3 h to obtain the catalyst. The content of Ni in the catalyst is 10 wt%, and the content of Zn is 3 wt% based on the total mass of the catalyst.

[0063] The catalyst is scanned by electron microscope, and the surface is nanosheet, the average thickness of the leaf is 17 nm, the average width of the leaf is 1671 nm, and the average length of the leaf is 1254 nm. The specific surface area of the catalyst is 89 m 2 / g, the pore volume is 0.35 cm 3 / g.

[0064] Comparative Example 1

[0065] The embodiment provides a phenylacetylene selective hydrogenation catalyst, and a preparation method thereof.

[0066] The composite carrier with a weight ratio of alumina to silica of 20:1 is weighed as 20 g, and is added into a mixed solution of nickel nitrate, lanthanum nitrate and zinc nitrate for impregnation by an equal-amount impregnation method. The catalyst is dried at 120 DEG C for 6 h and calcined at 400 DEG C for 8 h to obtain a nickel-based catalyst. The content of nickel is 12% of the weight of the carrier, the content of lanthanum is 0.8%, and the content of zinc is 1.5%.

[0067] The catalyst is scanned by electron microscope, and the surface is nanosheet, the average thickness of the leaf is 17 nm, the average width of the leaf is 1671 nm, and the average length of the leaf is 1254 nm. The specific surface area of the catalyst is 89 m Figure 2 Figure 2 ​It can be seen that the catalyst surface exists in the form of irregular spherical aggregates, which is easy to agglomerate during high-temperature reduction or long-period evaluation.

[0068] Comparative Example 2

[0069] The present comparative example provides a phenylacetylene selective hydrogenation catalyst, and the preparation method is as follows:

[0070] Nickel nitrate and zinc chloride were dissolved in water to prepare an impregnation solution, and then the carrier alumina was put into the impregnation solution for impregnation by the equal volume impregnation method. The impregnated carrier was dried at 130°C for 2.5h and then calcined at 330°C for 5h to obtain the catalyst. The Ni content in the catalyst was 12.5wt% and the Zn content was 1.5wt% based on the total mass of the catalyst being 100%. The specific surface area of the catalyst was 107m 2 / g, and the pore volume was 0.41cm 3 / g.

[0071] Comparative Example 3

[0072] The present comparative example provides a phenylacetylene selective hydrogenation catalyst, and the preparation method is as follows:

[0073] 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 transparent solution. Then the solution was transferred to a high-pressure reaction kettle, and hydrogen was introduced to remove the air in the reaction kettle. The hydrogen pressure in the reaction kettle was set to 0.5MPa, and the reaction kettle was sealed. The reaction kettle was heated to 120°C, and reacted for 24 hours. After the reaction was completed, the reaction kettle was naturally cooled to room temperature, the gas in the reaction kettle was discharged, the reaction kettle was opened, and the reaction slurry was collected. The reaction slurry was suction filtered, and the filtrate was washed repeatedly with deionized water for 3 times. Then the filtrate was transferred to an 80°C oven for drying for 8 hours to obtain a γ-alumina precursor, boehmite. Finally, the boehmite was placed in a muffle furnace, and heated from room temperature to 550°C at a rate of 2°C / min, and kept for 6 hours before naturally cooling down to obtain leaf-shaped nano γ-alumina. The specific surface area of the obtained γ-alumina was 267m 2 / g, and the average pore size was 6.7nm.

[0074] Then, nickel acetate and zinc nitrate were dissolved in deionized water to prepare an impregnation solution, which was then put into the above-mentioned leaf-shaped nano γ-alumina carrier for impregnation. The impregnated leaf-shaped nano γ-alumina carrier was dried at 110°C for 5h and then calcined at 360°C for 4.5h to obtain the catalyst. The Ni content in the catalyst was 11.5wt% and the Zn content was 2% based on the total mass of the catalyst being 100%.

[0075] Comparative Example 4

[0076] The comparative example provides a phenylacetylene selective hydrogenation catalyst, and a preparation method thereof is as follows:

[0077] Nickel nitrate and zinc fluoroborate are dissolved in water to prepare an impregnation solution, then the carrier alumina is put into the impregnation solution to be impregnated by using an equal volume impregnation method, and the impregnated carrier is dried at 110 DEG C for 3.5 h and calcined at 450 DEG C for 3 h to obtain the catalyst, so that the content of Ni in the catalyst is 10 wt%, and the content of Zn is 3% based on the total mass of the catalyst. The specific surface area of the catalyst is 85 m 2 / g, and the pore volume is 0.33 cm 3 / g.

[0078] Catalytic performance evaluation

[0079] Raw material composition and analysis method:

[0080] Main composition of raw material: 35 wt% of styrene (ST for short) and 0.5 wt% of phenylacetylene (PA for short).

[0081] Composition of raw material and product: Agilent 7890B gas chromatography is used to analyze the raw material and composition.

[0082] Catalyst evaluation conditions: the catalyst is reduced at 350 DEG C for 12 h under a hydrogen atmosphere, an adiabatic bed reactor is used, the reaction temperature is 28 DEG C, the reaction pressure is 0.3 MPa, the molar ratio of H2 / PA is 3.5:1, the liquid hourly space velocity is 1.5 h -1 , and the catalyst loading amount is 150 ml.

[0083] Reaction process flow: after the C8 fraction is metered by a metering pipe, the plunger pump is used to increase the reaction pressure, the hydrogen gas is mixed after preheating, and then the mixture is introduced into the catalyst bed from the lower part of the reactor, the reaction product is introduced into a gas-liquid separator after cooling for separation, the separated H2 is discharged after pressure reduction and metered by a wet flowmeter, the liquid is discharged into a product storage tank, and Agilent 7890B gas chromatography is used to analyze the content of ST, PA and other components.

[0084] The evaluation conditions and results of the catalyst prepared in each example and comparative example are shown in Table 1.

[0085] Table 1 Evaluation conditions and results of examples and comparative examples

[0086]

[0087]

[0088] As shown in the data in the above table, the phenylacetylene selective hydrogenation catalyst provided by the present application has excellent hydrogenation activity and selectivity in the presence of styrene, the PA hydrogenation rate is high, and the ST loss is low. The selectivity of the catalyst prepared by the existing impregnation method for phenylacetylene is obviously reduced.

[0089] The above examples are typical examples for illustrating the technical solutions of the present application, and the present application is limited by the protection scope of the claims and the summary, and is not limited by the described embodiments. Simple replacement or change of the present application is still within the protection scope of the present application.

Claims

1. A catalyst for selective hydrogenation of phenylacetylene in the presence of styrene, the support being alumina, characterized in that, The phenylacetylene selective hydrogenation catalyst is a Ni-Zn catalyst with regular nano-leaf structure in surface morphology. The average thickness of the leaf is 5-20 nm, the average width of the leaf is 300-3000 nm, the average length of the leaf is 300-3000 nm, the specific surface area is 70-240 m 2 / g, and the pore volume is 0.25-0.60 cm 3 / g. The Ni content is 8wt%-18wt% and the Zn content is 0.5wt%-4wt% based on the total mass of the phenylacetylene selective hydrogenation catalyst. The preparation method of the phenylacetylene selective hydrogenation catalyst in the presence of styrene comprises the following steps: 1) The alumina carrier is immersed in a nickel salt aqueous solution, dried and calcined to obtain a semi-finished catalyst; the nickel content in the semi-finished catalyst is 70wt%-95wt% of the nickel content in the phenylacetylene selective hydrogenation catalyst; 2) The nickel salt and the zinc salt are dissolved in an alcohol-water mixed solution, and then the semi-finished catalyst is added, stirred uniformly, and then the obtained solid is washed, dried and calcined to obtain the phenylacetylene selective hydrogenation catalyst in the presence of styrene; The temperature of the hydrothermal reaction is 100-250℃ and the time is 2-48h.

2. The selective hydrogenation catalyst of the phenylacetylene in the presence of styrene according to claim 1, characterized in that, The average thickness of the leaf is 8-15 nm, the average width of the leaf is 500-1500 nm, the average length of the leaf is 500-1500 nm, and the specific surface area is 90-160 m 2 / g, and the pore volume is 0.35-0.50 cm 3 / g.

3. The selective phenylacetylene hydrogenation catalyst in the presence of styrene according to claim 1, wherein the catalyst is characterized by The Ni content is 10wt%-15wt%.

4. The selective hydrogenation catalyst of the phenylacetylene in the presence of styrene according to claim 1, wherein the metal oxide is at least one selected from the group consisting of alumina, titania, zirconia, ceria, and magnesia. The Zn content is 1wt%-2wt%.

5. The selective hydrogenation catalyst for phenylacetylene in the presence of styrene as described in claim 1, characterized in that, In the alcohol-water mixed solution, the volume ratio of alcohol to water is 4-1:1, and the alcohol is at least one of methanol, anhydrous ethanol and propanol.

6. The selective hydrogenation catalyst for phenylacetylene in the presence of styrene as described in claim 1, characterized in that, The zinc salt is a soluble zinc salt; and the nickel salt is at least one of nickel sulfate, nickel nitrate, nickel chloride and nickel acetate.

7. The selective hydrogenation catalyst of the phenylacetylene in the presence of styrene according to claim 1, wherein the metal is at least one selected from the group consisting of Pt, Pd, Ni, Co, Fe, Ru, Rh, Ir, Cu, Ag, Au, Zn, and Cd. The temperature of the hydrothermal reaction is 120-200℃ and the time is 4-24h.

8. The selective hydrogenation catalyst for phenylacetylene in the presence of styrene as described in claim 1, characterized in that, The drying temperature is 80-150℃, the calcination temperature is 300-500℃, and the calcination time is 2-8h.

9. The selective hydrogenation catalyst for phenylacetylene in the presence of styrene as described in claim 5, characterized in that, In the alcohol-water mixed solution, the volume ratio of alcohol to water is 2-1:

1.

10. The selective hydrogenation catalyst of the phenylacetylene in the presence of styrene according to claim 5, wherein the metal is at least one selected from the group consisting of Pt, Pd, Ni, Co, Fe, Ru, Rh, Ir, Cu, Ag, Au, Zn, and Cd. The alcohol is anhydrous ethanol.

11. The selective hydrogenation catalyst for phenylacetylene in the presence of styrene as described in claim 6, characterized in that, The zinc salt is at least one of zinc nitrate, zinc chloride, zinc fluoroborate and zinc sulfate.

12. The selective hydrogenation catalyst for phenylacetylene in the presence of styrene as described in claim 6, characterized in that, The nickel salt is selected from nickel nitrate and / or nickel acetate.

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