Selective hydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention discloses a selective hydrogenation catalyst and a preparation method and application thereof. The selective hydrogenation catalyst comprises a carrier and an active component loaded on the carrier, wherein the carrier is a metal composite oxide modified by an organic cation quaternary ammonium salt and a silane reagent; the organic cation quaternary ammonium salt is selected from at least one of long-chain alkyl quaternary ammonium salts with more than C6; the silane reagent is selected from at least one of alkoxy silane with 1 to 4 carbon atoms; the active component comprises a main active component and an optional auxiliary active component, and the main active component comprises Cu; the auxiliary active component is selected from one or more of Au, Ag and Ru. The selective hydrogenation catalyst has high crushing strength, high selectivity and low-temperature reaction activity, also has stable hydrogenation activity, can be used for low-carbon olefin selective hydrogenation to remove impurities such as alkyne and alkadiene, and can be used for a long period of time.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, and more specifically, to selective hydrogenation catalysts, their preparation methods, and applications. Background Technology

[0002] Low-carbon olefins typically refer to olefins with C2-C4 carbon atoms, such as ethylene, propylene, and butene. They are fundamental raw materials in petrochemical production, used to produce products like polyethylene, polypropylene, acrylonitrile, and ethylene oxide, and have wide applications in plastics, rubber, resins, polymers, pharmaceuticals, and pesticides. Low-carbon hydrocarbons also include some alkynes and dienes, separated from petrochemical plants. Typically, C2-C4 low-carbon olefins contain trace amounts of alkynes. These impurities can cause catalyst poisoning and deactivation, reduced reaction rates, or decreased product quality in downstream reactions. These impurities can poison catalysts in monoolefin polymerization reactions. Therefore, in petrochemical production, when low-carbon olefins are used as raw materials, the trace amounts of alkynes they contain should first be selectively hydrogenated using catalytic methods. While selectively hydrogenating low-carbon hydrocarbons to remove alkynes, it is crucial to ensure that the main component, the low-carbon olefin, remains unconverted or has a low conversion rate. This requires catalysts with high low-temperature activity and high selectivity.

[0003] Traditional C3 hydrogenation catalysts use Al2O3 as a support, Pd as the active component, and Ag as a co-active component. The catalyst is prepared using an impregnation method. During the impregnation and drying processes, the surface tension and solvation effects of the impregnation solution significantly influence the catalyst, causing the metal active component precursor to deposit as aggregates on the support surface. Furthermore, the distribution of Pd and Ag is not ideal, making it difficult to control the catalyst activity. The selectivity of the catalyst mainly depends on the pore size and dispersion state of the active component. Because the dispersion of the active component during catalyst preparation is affected by the number of surface groups on the support and solvation, the dispersion of the active component is highly random, resulting in poor reproducibility and ultimately unsatisfactory catalytic reaction performance.

[0004] CN101433845A discloses a selective hydrogenation catalyst for unsaturated hydrocarbons and its preparation method. This catalyst uses alumina as a support and palladium as the active component. The catalyst's resistance to impurities and coking is improved by adding rare earth and alkaline earth metals and fluorine, but its selectivity is not ideal.

[0005] CN104096572A discloses a hydrogenation catalyst in which the active components are Pd, Ag, and Ni. Pd and Ag are supported using an aqueous solution impregnation method, while Ni is supported using a W / O microemulsion impregnation method. Using this method, Pd / Ag and Ni are located in channels of different pore sizes, allowing the generated green oil to undergo saturated hydrogenation in the macropores, thus reducing catalyst coking. However, the reduction temperature of Ni often reaches around 500℃, at which temperature reduced Pd atoms easily aggregate, causing a significant decrease in catalyst activity. This necessitates a substantial increase in the amount of active components to compensate for the activity loss, but this in turn leads to a decrease in selectivity. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of low low-temperature activity, poor selectivity, and poor stability of existing selective hydrogenation catalysts, and to provide selective hydrogenation catalysts, their preparation methods, and applications. This invention can significantly improve the dispersion of active components on the support surface by modifying the support. The catalyst prepared by it has the advantages of high crushing strength, high selectivity, high low-temperature activity, and stable hydrogenation activity, and can be used for a long period of time.

[0007] To achieve the above objectives, a first aspect of the present invention provides a selective hydrogenation catalyst, the selective hydrogenation catalyst comprising a support and an active component supported on the support; wherein the support is a metal composite oxide modified with an organic cationic quaternary ammonium salt and a silane reagent; the organic cationic quaternary ammonium salt is selected from at least one of long-chain alkyl quaternary ammonium salts with a chain of C6 or more; the silane reagent is selected from at least one of C1-C4 alkoxysilanes; the active component comprises a main active component and an optional co-active component, the main active component comprising Cu; the co-active component is selected from one or more of Au, Ag, and Ru.

[0008] A second aspect of the present invention provides a method for preparing a selective hydrogenation catalyst, the method comprising the following steps:

[0009] (1) The surface of the metal composite oxide is treated with an organic cationic quaternary ammonium salt, and then treated with a silane reagent to obtain a modified composite oxide carrier; wherein the organic cationic quaternary ammonium salt is selected from at least one of long-chain alkyl quaternary ammonium salts of C6 or above; and the silane reagent is selected from at least one of C1-C4 alkoxysilanes.

[0010] (2) The modified composite oxide carrier is mixed and impregnated with the active component metal salt solution, and then filtered, dried and calcined in sequence.

[0011] A third aspect of the present invention provides a selective hydrogenation catalyst prepared by the preparation method described in the second aspect above.

[0012] The fourth aspect of the present invention provides the application of the selective hydrogenation catalyst described in the first or third aspect above in the selective hydrogenation of C2-4 fraction.

[0013] The fifth aspect of the present invention provides a method for selective hydrogenation of a C2-4 fraction, the method comprising: contacting the C2-4 fraction with a selective hydrogenation catalyst under hydrogenation reaction conditions; wherein the selective hydrogenation catalyst is the selective hydrogenation catalyst described in the first or third aspect of the preceding claims.

[0014] The beneficial technical effects achieved by the present invention through the above technical solution are as follows:

[0015] (1) In this invention, organic cationic quaternary ammonium salt and silane reagents are used as modifiers to modify metal composite oxides. When these are used as supports to prepare catalysts, the dispersion of active components on the support surface can be significantly improved, and the metal atom clusters of active components can be controlled to be below 5 nm.

[0016] (2) The catalyst prepared by the modified composite oxide support of the present invention has high crushing strength, high selectivity and low temperature reaction activity, and stable hydrogenation activity. It can be used for selective hydrogenation of low carbon olefins to remove impurities such as alkynes and dienes, and can be used for a long period of time.

[0017] (3) The catalyst of the present invention has a simple preparation process, mild reaction conditions, low production cost, and can operate stably for a long time in production, and has industrial application value. Attached Figure Description

[0018] Figure 1 This is a TEM image of catalyst F1 obtained in Example 6. Detailed Implementation

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0020] A first aspect of the present invention provides a selective hydrogenation catalyst, the selective hydrogenation catalyst comprising a support and an active component supported on the support; wherein the support is a metal composite oxide modified with an organic cationic quaternary ammonium salt and a silane reagent; the organic cationic quaternary ammonium salt is selected from at least one of long-chain alkyl quaternary ammonium salts with a chain of C6 or more; the silane reagent is selected from at least one of C1-C4 alkoxysilanes; the active component comprises a main active component and an optional co-active component, the main active component comprising Cu; the co-active component is selected from one or more of Au, Ag, and Ru.

[0021] According to the present invention, when metal composite oxides are modified by using organic cationic quaternary ammonium salts and silane reagents as modifiers and then used as supports for the preparation of catalysts, the dispersion of active components on the support surface can be significantly improved and the metal atom clusters of active components can be controlled to be below 5 nm.

[0022] According to the present invention, the crushing strength of the catalyst prepared by the modified composite oxide support is improved compared with that of the catalyst prepared by the unmodified composite oxide support. This helps to overcome the disadvantage of low crushing strength caused by the introduction of TiO2 into the support (for example, 2% increases from 160 N / cm to 196 N / cm, and 5% increases from 160 N / cm to 220 N / cm). The higher crushing strength can effectively avoid the pulverization problem of the catalyst during long-term operation. Furthermore, it can be produced by extrusion, and the irregular surface can be used to increase the contact area between the outer surface of the catalyst and the physical environment, thereby improving the activity of the catalyst.

[0023] According to some embodiments of the present invention, the organic cationic quaternary ammonium salt is selected from at least one of bis(octadecyl)dimethyl quaternary ammonium salt, hexadecyltrimethyl quaternary ammonium salt, and C12-18 alkyldimethylbenzyl quaternary ammonium salt.

[0024] According to a preferred embodiment of the present invention, the organic cationic quaternary ammonium salt is selected from at least one of bis(octadecyl)dimethylammonium chloride, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, dodecyldimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium chloride, hexadecyldimethylbenzylammonium chloride and octadecyldimethylbenzylammonium chloride.

[0025] According to some embodiments of the present invention, the silane reagent is selected from at least one of triethoxysilane, trimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, and vinyltrimethylsiloxane.

[0026] According to a preferred embodiment of the present invention, the silane reagent is selected from triethoxysilane and / or trimethoxysilane.

[0027] According to some embodiments of the present invention, the mass ratio of the metal composite oxide to the organic cationic quaternary ammonium salt is 1:0.01-1.

[0028] According to the present invention, by controlling the above ratio, the hydroxyl groups on the carrier surface are increased, thereby improving the affinity between the carrier surface and the additives.

[0029] According to some embodiments of the present invention, the mass ratio of the metal composite oxide to the silane reagent is 1:0.01-1.

[0030] According to the present invention, by controlling the above ratio, the hydrophobicity of the support surface can be increased, and the dispersion of the catalyst active component on the support surface can be improved.

[0031] According to some embodiments of the present invention, the metal composite oxide includes Al2O3 and TiO2.

[0032] According to a preferred embodiment of the present invention, the metal composite oxide comprises 5-25 parts by weight of TiO2 and 75-95 parts by weight of Al2O3.

[0033] According to the present invention, controlling Al2O3 and TiO2 in the above ratio can improve crushing strength, increase specific surface area and pore volume, improve the electronic properties of the catalyst surface, and enhance catalyst activity.

[0034] According to some embodiments of the present invention, the specific surface area of ​​the carrier is 30-150 m². 2 / g, preferably 50-90m 2 / g.

[0035] According to some embodiments of the present invention, the pore volume of the carrier is 0.2-0.8 mL / g, preferably 0.3-0.4 mL / g.

[0036] According to a preferred embodiment of the present invention, based on 100 parts by weight of the total weight of the catalyst, the content of the main active component Cu, calculated as its oxide, is 1-15 parts by weight; and the content of the auxiliary active component, calculated as its oxide, is 0.1-3 parts by weight.

[0037] According to a preferred embodiment of the present invention, the active component is distributed on the modified composite oxide support in the form of metal atom clusters, wherein the particle size of the metal atom clusters is less than 5 nm.

[0038] A second aspect of the present invention provides a method for preparing a selective hydrogenation catalyst, the method comprising the following steps:

[0039] (1) The surface of the metal composite oxide is treated with an organic cationic quaternary ammonium salt, and then treated with a silane reagent to obtain a modified composite oxide carrier; wherein the organic cationic quaternary ammonium salt is selected from at least one of long-chain alkyl quaternary ammonium salts of C6 or above; and the silane reagent is selected from at least one of C1-C4 alkoxysilanes.

[0040] (2) The modified composite oxide carrier is mixed and impregnated with the active component metal salt solution, and then filtered, dried and calcined in sequence.

[0041] According to some embodiments of the present invention, the organic cationic quaternary ammonium salt is selected from at least one of bis(octadecyl)dimethyl quaternary ammonium salt, hexadecyltrimethyl quaternary ammonium salt, and C12-18 alkyldimethylbenzyl quaternary ammonium salt.

[0042] According to a preferred embodiment of the present invention, the organic cationic quaternary ammonium salt is selected from at least one of bis(octadecyl)dimethylammonium chloride, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, dodecyldimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium chloride, hexadecyldimethylbenzylammonium chloride and octadecyldimethylbenzylammonium chloride.

[0043] According to the present invention, an organic cationic quaternary ammonium salt solution is used to impregnate metal composite oxides, which effectively controls the possibility of metal ions participating in the oxidation reaction.

[0044] According to a preferred embodiment of the present invention, the mass concentration of the organic cation quaternary ammonium salt in the organic cation quaternary ammonium salt solution is 1-10 wt%.

[0045] According to some embodiments of the present invention, the silane reagent is selected from at least one of triethoxysilane, trimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, and vinyltrimethylsiloxane.

[0046] According to a preferred embodiment of the present invention, the silane reagent is selected from triethoxysilane and / or trimethoxysilane.

[0047] According to the present invention, a silane reagent is used to impregnate the metal composite oxide after quaternary ammonium salt impregnation to increase the hydrophobicity of the carrier surface.

[0048] According to a preferred embodiment of the present invention, the mass concentration of alkoxysilane (siloxane) in the silane reagent is 1-10 wt%.

[0049] According to some embodiments of the present invention, the mass ratio of the metal composite oxide to the organic cationic quaternary ammonium salt is 1:0.01-1.

[0050] According to the present invention, by controlling the above ratio, the hydroxyl groups on the carrier surface are increased, thereby improving the affinity between the carrier surface and the additives.

[0051] According to some embodiments of the present invention, the mass ratio of the metal composite oxide to the silane reagent is 1:0.01-1.

[0052] According to the present invention, by controlling the above ratio, the hydrophobicity of the support surface can be increased, and the dispersion of the catalyst active component on the support surface can be improved.

[0053] According to some embodiments of the present invention, the metal composite oxide includes Al2O3 and TiO2.

[0054] According to a preferred embodiment of the present invention, the metal composite oxide comprises 5-25 parts by weight of TiO2 and 75-95 parts by weight of Al2O3.

[0055] According to the present invention, controlling Al2O3 and TiO2 in the above ratio can improve crushing strength, increase specific surface area and pore volume, improve the electronic properties of the catalyst surface, and enhance catalyst activity.

[0056] According to some embodiments of the present invention, the active component metal salt solution includes a main active component salt solution and a co-active component salt solution.

[0057] According to some embodiments of the present invention, the main active component salt is selected from at least one of copper sulfate, nitrate, soluble carboxylate, phosphate and halide.

[0058] Preferably, the main active component salt is selected from at least one of copper sulfate, copper nitrate, copper chloride, and copper acetate.

[0059] According to some embodiments of the present invention, the co-active component salt is selected from at least one of the nitrate, soluble carboxylate and halide of the co-active component, and the co-active component is selected from at least one of Au, Ag and Ru.

[0060] Preferably, the auxiliary active component salt is selected from at least one of gold nitrate, silver nitrate, and ruthenium nitrate.

[0061] According to the present invention, the active component metal salt solution includes oxalate, sulfate, nitrate and halide of active metal; the type of solution can be an aqueous solution or a salt solution formed by using ethanol, benzene or other solvents.

[0062] Preferably, the main active component is typically a copper salt, including but not limited to: copper sulfate, nitrate, soluble carboxylate, phosphate and halide. The type of copper sulfate, copper nitrate, copper chloride or copper acetate solution is not particularly limited. It can be an aqueous solution or an organic copper salt solution formed by using ethanol, benzene or other solvents.

[0063] Preferably, the salt of the co-active component can be understood as the salt of the co-active component commonly used in catalysts for selective hydrogenation, including but not limited to: at least one of gold salts, silver salts, and ruthenium salts; nitrates, soluble carboxylates, and halides of various co-active components, preferably nitrates, hydrochlorides, oxalates, or acetates; the type of salt solution of the co-active component is not particularly limited, and can be an aqueous solution or an organic salt solution formed using ethanol, benzene, etc. as solvents. Examples include gold nitrate, silver nitrate, and ruthenium nitrate.

[0064] The present invention preferably uses an aqueous solution of inorganic salts as the salt solution of the active component, thus avoiding the problems of high cost and environmental pollution associated with the use of organic salt solutions.

[0065] According to this invention, the water absorption rate of the support needs to be measured during catalyst preparation. The specific method is as follows:

[0066] Weigh an appropriate amount of carrier (mass A), add an appropriate amount of deionized water and soak for 15-120 minutes. Use filter paper to absorb excess water until the carrier is just completely wetted, and weigh it (mass B). Calculate the carrier water absorption rate = (BA) / A*100%.

[0067] According to some embodiments of the present invention, the volume of the active component metal salt solution is 0.8-2.5 times the equivalent volume of the pore volume of the modified composite oxide support.

[0068] The concentrations of copper salt, silver salt, and ruthenium salt solutions were prepared based on the carrier's water absorption rate and the equal-volume impregnation method.

[0069] According to a preferred embodiment of the present invention, the concentration of Cu in the copper salt solution is 0.1-0.6 mol / L.

[0070] According to a preferred embodiment of the present invention, the concentration of Au in the gold salt solution is 0.01-0.6 mol / L.

[0071] According to a preferred embodiment of the present invention, the concentration of Ag in the silver salt solution is 0.01-0.6 mol / L.

[0072] According to a preferred embodiment of the present invention, the concentration of Ru in the ruthenium salt solution is 0.01-0.3 mol / L.

[0073] According to some embodiments of the present invention, the surface treatment conditions include: a temperature of 60-150°C, preferably 90-120°C; and a time of 1-12 hours, preferably 2-8 hours.

[0074] According to some embodiments of the present invention, the processing conditions include: a temperature of 60-150°C, preferably 90-120°C; and a time of 1-12 hours, preferably 2-8 hours.

[0075] According to the present invention, in step (1), after treatment with silane reagents, the process further includes a filtration and drying step, wherein the drying temperature is 60-150℃, preferably 90-120℃, and the drying time is 1-12h, preferably 2-8h.

[0076] According to some embodiments of the present invention, the conditions for the mixed impregnation include: a temperature of 20-60°C and a time of 1-12 hours.

[0077] According to the present invention, it also includes a process of washing the precipitate formed after mixed impregnation, specifically including: washing the precipitate with deionized water until neutral.

[0078] According to some embodiments of the present invention, the drying conditions include: a temperature of 60-150°C, preferably 90-120°C; and a time of 1-12 hours, preferably 2-8 hours.

[0079] According to some embodiments of the present invention, the calcination conditions include: a temperature of 300-800°C, preferably 350-600°C; a time of 1-12 hours, preferably 2-8 hours; and an atmosphere of air and / or nitrogen.

[0080] A third aspect of the present invention provides a selective hydrogenation catalyst prepared by the preparation method described in the second aspect above.

[0081] According to this invention, the specific combination of the support and several metal active components makes this catalyst particularly suitable for the hydrogenation and alkyne removal reaction of low-carbon olefins. The catalyst provided by this invention exhibits high selectivity and high low-temperature activity in the hydrogenation and alkyne removal of low-carbon hydrocarbons. The added metals increase the number of deoxygenation active sites, provide good resistance to impurities, and can simultaneously remove trace amounts of oxygen and alkynes from low-carbon olefins. Furthermore, it can promote crystal nucleation growth at different pH values, promote the formation of stable structures in metal oxides, improve product selectivity, and maintain stable hydrogenation activity.

[0082] The fourth aspect of the present invention provides the application of the selective hydrogenation catalyst described in the first or third aspect above in the selective hydrogenation of C2-4 fraction.

[0083] According to the present invention, the selective hydrogenation catalyst prepared based on the modified composite oxide support can be used for the selective hydrogenation of low-carbon olefins to remove impurities such as alkynes and dienes. It has the advantages of good activity, high selectivity, high low-temperature activity and stable hydrogenation activity, and can be used for a long period of time.

[0084] The catalyst of this invention has high low-temperature reactivity and selectivity, its preparation process is simple, the reaction conditions are mild, the production cost is low, and it can operate stably for a long time in production, thus having industrial application value.

[0085] According to the present invention, selective hydrogenation refers to the selective hydrogenation reaction of hydrogen with impurities to generate C2-4 olefins.

[0086] According to some embodiments of the present invention, the C2-4 fraction contains C2-4 olefins and / or C2-4 alkanes.

[0087] According to the present invention, the C2-4 fraction may contain both olefins and alkanes, or may contain only olefins or only alkanes.

[0088] According to a preferred embodiment of the present invention, the content of the C2-4 olefin is 0-99.99 wt%.

[0089] According to a preferred embodiment of the present invention, the content of the C2-4 alkane is 0-99.99 wt%.

[0090] According to some embodiments of the present invention, the C2-4 fraction also contains impurities, including C2-4 alkynes and optionally C3 dienes.

[0091] According to a preferred embodiment of the present invention, the content of the C2-4 alkyne is 0.01-5 wt%, preferably 0.01-3 wt%.

[0092] According to a preferred embodiment of the present invention, the content of the C3 diene is 0-5 wt%.

[0093] According to the present invention, the C2-4 fraction is described as an example of the C3 fraction, which includes 93-96 parts by weight of propylene, 2.0-2.5 parts by weight of propane, and 1-5 parts by weight of propyne and propadiene.

[0094] The fifth aspect of the present invention provides a method for selective hydrogenation of a C2-4 fraction, the method comprising: contacting the C2-4 fraction with a selective hydrogenation catalyst under hydrogenation reaction conditions; wherein the selective hydrogenation catalyst is the selective hydrogenation catalyst described in the first or third aspect of the preceding claims.

[0095] According to some embodiments of the present invention, the hydrogenation reaction conditions include: using a fixed-bed reactor, with a reactor inlet temperature of 20-50°C, preferably 20-25°C; and a reaction pressure of 0.5-0.8 MPa, preferably 0.5-0.7 MPa.

[0096] According to some embodiments of the present invention, the molar ratio of hydrogen to (alkyne + diene) is 1-2.5:1, preferably 1.5-2:1.

[0097] According to some embodiments of the present invention, the recycling ratio of hydrogen to (alkyne + diene) is 10-30:1, preferably 20-25:1.

[0098] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited to the following description.

[0099] Unless otherwise specified in the following preparation examples, embodiments, and comparative examples, all conditions should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0100] The TiO2 content was determined using a spectrophotometer, and the parameter detection method was the standard curve method. The principle utilized was that in sulfuric acid solution, Ti... 4+ It forms a yellow complex with hydrogen peroxide. Titanium dioxide reacts with hot sulfuric acid to form titanyl sulfate, which then reacts with hydrogen peroxide to form a stable, orange-yellow [TiO(H₂O₂)]₂. 2- The results were measured at 430 nm using a spectrophotometer.

[0101] The specific surface area, pore volume, and most probable pore size of the support were determined using an ASAP 2020 adsorption analyzer (N2 adsorption-desorption method) from Micron Instruments, Inc., USA. The parameters were measured using the static volumetric method. Before testing, the catalyst samples were degassed at 623 K for 4 h and then adsorbed with nitrogen at liquid nitrogen temperature. Sample data were processed using AMSM software, and the specific surface area was obtained using the Brunauer-Emmet-Teller (BET) method. The average pore size was obtained from the nitrogen adsorption isotherm using the Barrett-Joyner-Halenda (BJH) method, and the pore volume was obtained using the P / Po single-point desorption curve.

[0102] The contents of Cu, Au, Ag, and Ru in the catalyst were determined using an ICP atomic emission spectrometer, based on the JYT015 General Rules for Inductively Coupled Plasma Atomic Emission Spectrometry. A PerkinElmer (PE) Optima 8300 full-spectrum direct-reading ICP spectrometer was used, featuring an echelle grating, a solid-state detector, and dual-path dual-solid-state detectors in the ultraviolet and visible regions. The instrument employed planar plasma technology to ensure minimal argon gas consumption.

[0103] Preparation Example 1

[0104] 100g of TiO2-Al2O3 support (TiO2 content 8 parts) produced by Yantai Heng Hui Chemical Co., Ltd. was selected and 100mL of a 5wt% dioctadecyldimethylammonium chloride methanol solution was added. After impregnation for 2h, it was dried at 70℃ for 10h. 100g of a 0.1wt% vinyltrimethoxysiloxane aqueous solution was added dropwise to the dried support. After the addition was completed, the mixture was stirred evenly for 10 minutes and then dried at 70℃ for 10h to obtain modified composite oxide support A. The results are shown in Table 1.

[0105] Preparation Example 2

[0106] 100g of TiO2-Al2O3 support (TiO2 content 15 parts) produced by Yantai Heng Hui Chemical Co., Ltd. was selected and 100mL of a 5wt% hexadecyltrimethylammonium bromide methanol solution was added. After impregnation for 2h, it was dried at 80℃ for 10h. 100g of a 1wt% vinyltrimethoxysiloxane aqueous solution was added dropwise to the dried support. After the addition was completed, the mixture was stirred evenly for 20 minutes and then dried at 80℃ for 8h to obtain modified composite oxide support B. The results are shown in Table 1.

[0107] Preparation Example 3

[0108] 100g of TiO2-Al2O3 support (TiO2 content 15 parts) produced by Yantai Heng Hui Chemical Co., Ltd. was selected and 100mL of a 5wt% methanol solution of dodecyl dimethyl benzyl ammonium chloride was added. After impregnation for 2h, it was dried at 90℃ for 9h. 100g of a 2wt% vinyltrimethoxysiloxane aqueous solution was added dropwise to the dried support. After the addition was completed, the mixture was stirred evenly for 15 minutes and then dried at 90℃ for 9h to obtain modified composite oxide support C. The results are shown in Table 1.

[0109] Preparation Example 4

[0110] 100g of TiO2-Al2O3 support (TiO2 content 12 parts) produced by Yantai Heng Hui Chemical Co., Ltd. was selected and 100mL of a 5wt% methanol solution of tetradecyl dimethyl benzyl ammonium chloride was added. After impregnation for 2h, it was dried at 70℃ for 10h. 100g of a 3wt% vinyltrimethoxysiloxane aqueous solution was added dropwise to the dried support. After the addition was completed, the mixture was stirred evenly for 30 minutes and then dried at 150℃ for 5h to obtain modified composite oxide support D. The results are shown in Table 1.

[0111] Preparation Example 5

[0112] 100g of TiO2-Al2O3 support (TiO2 content 18 parts) produced by Yantai Heng Hui Chemical Co., Ltd. was selected and 100mL of a 5wt% hexadecyl dimethyl benzyl ammonium chloride methanol solution was added. After impregnation for 2h, it was dried at 60℃ for 12h. 100g of a 4wt% vinyltrimethoxysiloxane aqueous solution was added dropwise to the dried support. After the addition was completed, the mixture was stirred evenly for 20 minutes and then dried at 60℃ for 12h to obtain modified composite oxide support E. The results are shown in Table 1.

[0113] Preparation Example 6

[0114] 100g of TiO2-Al2O3 support (TiO2 content 25 parts) produced by Yantai Heng Hui Chemical Co., Ltd. was selected and 100mL of a 5wt% methanol solution of octadecyl dimethyl benzyl ammonium chloride was added. After impregnation for 2h, it was dried at 110℃ for 7h. 100g of a 5wt% vinyltrimethoxysiloxane aqueous solution was added dropwise to the dried support. After the addition was completed, the mixture was stirred evenly for 10 minutes and then dried at 110℃ for 7h to obtain the modified composite oxide support F. The results are shown in Table 1.

[0115] Preparation of Comparative Example 1

[0116] 100g of TiO2-Al2O3 support (TiO2 content 15 parts) produced by Yantai Heng Hui Chemical Co., Ltd. was selected. 100g of a 1wt% vinyltrimethoxysiloxane aqueous solution was added dropwise to the support. After the addition was complete, the mixture was stirred uniformly for 20 minutes, and then dried at 80℃ for 8 hours. 100mL of a 5wt% hexadecyltrimethylammonium bromide methanol solution was added to the dried support for impregnation for 2 hours, followed by drying at 80℃ for 10 hours to obtain the modified composite oxide support G. The results are shown in Table 1.

[0117] Preparation of Comparative Example 2

[0118] 100g of TiO2-Al2O3 support (TiO2 content 15 parts) produced by Yantai Heng Hui Chemical Co., Ltd. was selected and 100mL of a 5wt% hexadecyltrimethylammonium bromide methanol solution was added. After impregnation treatment for 2h, it was dried at 80℃ for 10h to obtain modified composite oxide support H. The results are shown in Table 1.

[0119] Preparation of Comparative Example 3

[0120] 100g of TiO2-Al2O3 support (TiO2 content 15 parts) produced by Yantai Heng Hui Chemical Co., Ltd. was selected, and 100g of a 1wt% vinyltrimethoxysiloxane aqueous solution was added dropwise to the support. After the addition was completed, the mixture was stirred evenly for 20 minutes, and then dried at 80℃ for 8 hours to obtain modified composite oxide support I. The results are shown in Table 1.

[0121] Preparation of Comparative Example 4

[0122] The TiO2-Al2O3 support (TiO2 content 15 parts) produced by Yantai Heng Hui Chemical Co., Ltd. is made of the same raw material as the support in Preparation Example 2, and is not subjected to surface activation treatment. It is referred to as support J.

[0123] Preparation of Comparative Example 5

[0124] The γ-Al2O3 support produced by Yantai Heng Hui Chemical Co., Ltd., without surface activation treatment, is denoted as support K. The results are shown in Table 1.

[0125] Table 1

[0126]

[0127] Example 1

[0128] (1) Prepare 0.4 L of copper nitrate solution with a Cu concentration of 0.1 mol / L and 0.1 L of silver nitrate solution with an Ag concentration of 0.01 mol / L according to the proportions shown in Table 3. Then mix the two to prepare a mixed metal salt solution of copper salt and silver salt. The content of active components is shown in Table 3.

[0129] (2) 100g of the modified composite oxide support A prepared in Example 1 was immersed in the metal salt solution prepared in step (1) above, immersed at 25°C for 3h, filtered, dried at 110°C for 6h, and then calcined at 700°C for 4h under nitrogen atmosphere to obtain catalyst A1.

[0130] Example 2

[0131] (1) Prepare 0.4 L of copper nitrate solution with a Cu concentration of 0.17 mol / L and 0.1 L of silver nitrate solution with an Ag concentration of 0.14 mol / L. Then mix the two to prepare a mixed metal salt solution of copper salt and silver salt. The content of active components is shown in Table 3.

[0132] (2) 100g of the modified composite oxide support A2 prepared in Example 2 was immersed in the metal salt solution prepared in step (1) above, immersed at 25°C for 4h, filtered, dried at 120°C for 5h, and then calcined at 750°C for 6h under nitrogen atmosphere to obtain catalyst B1.

[0133] Example 3-11

[0134] (1) Prepare copper nitrate solution and silver nitrate solution with the same concentration as in Example 2 according to the active component content shown in Table 3, and then mix them to prepare a mixed metal salt solution of copper salt and silver salt.

[0135] (2) 100g of the modified composite oxide support prepared in Preparation Examples 3-6 and the support prepared in Comparative Examples 1-5 were respectively immersed in the metal salt solution prepared in step (1) above, immersed at 25°C for 4h, filtered, dried at 120°C for 5h, and then calcined at 750°C for 6h under nitrogen atmosphere to obtain catalyst C1-K1.

[0136] The catalyst F1 obtained in Example 6 was characterized using the following method: A Jem-3010 high-resolution transmission electron microscope was used to observe the catalyst at an accelerating voltage of 200 kV for HR-TEM characterization. Before testing, the sample was thoroughly ground into powder. A small amount of the sample was added to anhydrous ethanol and placed in an ultrasonic cleaner (model PS-10, Shenzhen Jiekang Ultrasonic Cleaning Machine Co., Ltd.) for ultrasonic separation for 15-20 minutes. Finally, the suspension was continuously added dropwise onto a microgrid using a dropper and allowed to dry naturally to obtain the desired product. Figure 1 The TEM image of catalyst F1 shown is from... Figure 1 It can be seen that the active component particles are relatively uniformly dispersed, with a particle size of approximately 3-5 nm.

[0137] Example 12

[0138] (1) Prepare 0.4 L of copper nitrate solution with a concentration of 0.1 mol / L Cu and 80 mL of gold nitrate solution with a concentration of 0.01 mol / L Au. Then mix the copper salt and gold salt solutions to prepare a mixed metal salt solution. The content of active components is shown in Table 3.

[0139] (2) 100g of the modified composite oxide support A prepared in Example 1 was immersed in the metal salt solution prepared in step (1) above, immersed at 25°C for 3h, filtered, dried at 90°C for 6h, and then calcined at 800°C for 4h in air atmosphere to obtain catalyst A2.

[0140] Examples 13-22

[0141] (1) Prepare copper nitrate solution and gold nitrate solution with the same concentration as in Example 12 according to the active component content shown in Table 3, and then mix them to prepare a mixed metal salt solution of copper salt and gold salt.

[0142] (2) 100g of the modified composite oxide support prepared in Preparation Examples 2-6 and the support prepared in Comparative Examples 1-5 were respectively immersed in the metal salt solution prepared in step (1) above, immersed at 25°C for 3h, filtered, dried at 90°C for 6h, and then calcined at 800°C for 4h in air atmosphere to obtain catalyst B2-K2.

[0143] Example 23

[0144] (1) Prepare 0.4 L of copper nitrate solution with a concentration of 0.1 mol / L Cu, 0.1 L of silver nitrate solution with a concentration of 0.01 mol / L Ag, and 80 mL of gold nitrate solution with a concentration of 0.01 Au. Mix the three metal salt solutions to prepare a mixed metal salt solution; the content of active components is shown in Table 3.

[0145] (2) 100g of the modified composite oxide support A prepared in Example 1 was immersed in the metal salt solution prepared in step (1) above, immersed at 25°C for 3h, filtered, dried at 90°C for 6h, and then calcined at 800°C for 4h in air atmosphere to obtain catalyst A3.

[0146] Examples 24-33

[0147] (1) Prepare copper nitrate solution, silver nitrate solution and gold nitrate solution with the same concentration as in Example 23 according to the active component content shown in Table 3, and then mix the three metal salt solutions to prepare a mixed metal salt solution.

[0148] (2) 100g of the modified composite oxide support prepared in Preparation Examples 2-6 and the support prepared in Comparative Examples 1-5 were respectively immersed in the metal salt solution prepared in step (1) above, immersed at 25°C for 3h, filtered, dried at 90°C for 6h, and then calcined at 800°C for 4h in air atmosphere to obtain catalyst B3-K3.

[0149] Application examples

[0150] The catalyst prepared in the above examples was applied in the selective hydrogenation reaction of C3 fractions. The hydrogenation process was carried out using a fixed-bed pilot-scale evaluation device from Tuochuan Scientific Equipment Co., Ltd., with 50 mL of catalyst loaded. Reaction conditions: reaction pressure 0.5-0.7 MPa, hydrogen flow rate 40 mL / h, reactor inlet temperature 25°C, recycle ratio 20:1, and feed rate 25 mL / h.

[0151] The composition of the C3 fraction used in the selective hydrogenation reaction is shown in Table 2.

[0152] Table 2 Raw Material Composition

[0153] serial number composition weight 1 <![CDATA[Propane C3H8]]> 2.36 2 <![CDATA[Propylene C3H6]]> 93.17 3 Propylene MA 2.53 4 Propylene PD 1.84 5 other 0.1

[0154] The catalysts prepared in the above examples were evaluated under the same conditions, and the selective hydrogenation results are shown in Table 3.

[0155] The content of each component during the experiment was tested using a chromatograph. The formulas for calculating MAPD conversion and propylene selectivity are as follows:

[0156] MAPD conversion rate = (MAPD in feed - MAPD in product) ÷ (MAPD in feed)

[0157] Propylene selectivity = (Propylene in product - Propylene in feedstock) ÷ (MAPD in feedstock - MAPD in product)

[0158] MAPD refers to a mixture of propyne (Methylacetylene, MA) and propadiene (PD) in ethylene plants, which is a byproduct of the ethylene cracking process.

[0159] Table 3. Results of hydrogenation of C3 fractions using different catalysts

[0160]

[0161] The reaction results show that the catalysts prepared by different supports according to the present invention all exhibit high conversion rates and selectivity in the selective hydrogenation of C3 fractions.

[0162] The test results show that, using the catalyst prepared in this invention, the conversion rate of MAPD can reach over 99%, and the selectivity of propylene can reach over 93%.

[0163] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. (1230860)

[0164] I93165BHY

[0165] Within the scope of the technical concept of this invention, various simple modifications can be made to the technical solution of this invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be regarded as the content disclosed in this invention and are all within the protection scope of this invention.

Claims

1. A selective hydrogenation catalyst, characterized in that, The selective hydrogenation catalyst comprises a support and an active component supported on the support; wherein the support is a metal composite oxide modified with an organic cationic quaternary ammonium salt and a silane reagent; the organic cationic quaternary ammonium salt is selected from at least one of long-chain alkyl quaternary ammonium salts with a chain of C6 or more; the silane reagent is selected from at least one of alkoxysilanes with a chain of C1-C4; the active component comprises a main active component and an optional co-active component, wherein the main active component comprises Cu; and the co-active component is selected from one or more of Au, Ag, and Ru.

2. The selective hydrogenation catalyst according to claim 1, wherein, The organic cationic quaternary ammonium salt is selected from at least one of bis(octadecyl dimethyl) quaternary ammonium salt, hexadecyl trimethyl quaternary ammonium salt, and C12-18 alkyl dimethyl benzyl quaternary ammonium salt; preferably, the organic cationic quaternary ammonium salt is selected from at least one of bis(octadecyl dimethyl) ammonium chloride, hexadecyl trimethyl ammonium chloride, hexadecyl trimethyl ammonium bromide, dodecyl dimethyl benzyl ammonium chloride, tetradecyl dimethyl benzyl ammonium chloride, hexadecyl dimethyl benzyl ammonium chloride, and octadecyl dimethyl benzyl ammonium chloride; And / or, the silane reagent is selected from at least one of triethoxysilane, trimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane and vinyltrimethylsiloxane; preferably, the silane reagent is selected from triethoxysilane and / or trimethoxysilane.

3. The selective hydrogenation catalyst according to claim 1 or 2, wherein, The mass ratio of the metal composite oxide to the organic cationic quaternary ammonium salt is 1:0.01-1; And / or, the mass ratio of the metal composite oxide to the silane reagent is 1:0.01-1.

4. The selective hydrogenation catalyst according to any one of claims 1-3, wherein, The metal composite oxide includes Al2O3 and TiO2; Preferably, the metal composite oxide comprises 5-25 parts by weight of TiO2 and 75-95 parts by weight of Al2O3.

5. The selective hydrogenation catalyst according to any one of claims 1-4, wherein, The specific surface area of ​​the carrier is 30-150 m². 2 / g, preferably 50-90m 2 / g; And / or, the pore volume of the carrier is 0.2-0.8 mL / g, preferably 0.3-0.4 mL / g.

6. The selective hydrogenation catalyst according to any one of claims 1-5, wherein, Based on 100 parts by weight of the selected hydrogenation catalyst, the content of the main active component Cu, calculated as its oxide, is 1-15 parts by weight; and the content of the auxiliary active component, calculated as its oxide, is 0.1-3 parts by weight.

7. The selective hydrogenation catalyst according to any one of claims 1-6, wherein, The active component is distributed on the support in the form of metal atom clusters, wherein the particle size of the metal atom clusters is less than 5 nm.

8. A method for preparing a selective hydrogenation catalyst, characterized in that, The preparation method includes the following steps: (1) The surface of the metal composite oxide is treated with an organic cationic quaternary ammonium salt, and then treated with a silane reagent to obtain a modified composite oxide carrier; wherein the organic cationic quaternary ammonium salt is selected from at least one of long-chain alkyl quaternary ammonium salts of C6 or above; and the silane reagent is selected from at least one of C1-C4 alkoxysilanes. (2) The modified composite oxide carrier is mixed and impregnated with the active component metal salt solution, and then filtered, dried and calcined in sequence.

9. The preparation method according to claim 8, wherein, The organic cationic quaternary ammonium salt is selected from at least one of bis(octadecyl dimethyl) quaternary ammonium salt, hexadecyl trimethyl quaternary ammonium salt, and C12-18 alkyl dimethyl benzyl quaternary ammonium salt; preferably, the organic cationic quaternary ammonium salt is selected from at least one of bis(octadecyl dimethyl) ammonium chloride, hexadecyl trimethyl ammonium chloride, hexadecyl trimethyl ammonium bromide, dodecyl dimethyl benzyl ammonium chloride, tetradecyl dimethyl benzyl ammonium chloride, hexadecyl dimethyl benzyl ammonium chloride, and octadecyl dimethyl benzyl ammonium chloride; And / or, the silane reagent is selected from at least one of triethoxysilane, trimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, and vinyltrimethylsiloxane; preferably, the silane reagent is selected from triethoxysilane and / or trimethoxysilane; And / or, the mass ratio of the metal composite oxide to the organic cationic quaternary ammonium salt is 1:0.01-1; And / or, the mass ratio of the metal composite oxide to the silane reagent is 1:0.01-1; And / or, the metal composite oxide comprises Al2O3 and TiO2; preferably, by weight, the metal composite oxide comprises 5-25 parts of TiO2 and 75-95 parts of Al2O3. And / or, the active component metal salt solution comprises a primary active component salt solution and a secondary active component salt solution; wherein, the primary active component salt is selected from at least one of copper sulfate, nitrate, soluble carboxylate, phosphate, and halide, preferably from at least one of copper sulfate, copper nitrate, copper chloride, and copper acetate; the secondary active component salt is selected from at least one of the primary active component nitrate, soluble carboxylate, and halide, and the secondary active component is selected from at least one of Au, Ag, and Ru, preferably from at least one of gold nitrate, silver nitrate, and ruthenium nitrate; And / or, the volume of the active component metal salt solution is 0.8-2.5 times the equivalent volume of the pore volume of the modified composite oxide support.

10. The preparation method according to claim 8 or 9, wherein, The surface treatment conditions include: a temperature of 60-150℃, preferably 90-120℃; and a time of 1-12h, preferably 2-8h. And / or, the conditions for the treatment include: a temperature of 60-150°C, preferably 90-120°C; and a time of 1-12 hours, preferably 2-8 hours. And / or, the conditions for the mixed impregnation include: a temperature of 20-60°C and a time of 1-12 hours; And / or, the drying conditions include: a temperature of 60-150°C, preferably 90-120°C; and a time of 1-12 hours, preferably 2-8 hours. And / or, the calcination conditions include: a temperature of 300-800℃, preferably 350-600℃; a time of 1-12h, preferably 2-8h; and an atmosphere of air and / or nitrogen.

11. The selective hydrogenation catalyst prepared by the method according to any one of claims 8-10.

12. The use of the selective hydrogenation catalyst according to any one of claims 1-7 and 11 in the selective hydrogenation of C2-4 fraction.

13. The application according to claim 12, wherein, The C2-4 fraction contains C2-4 olefins and / or C2-4 alkanes; Preferably, the content of the C2-4 olefin is 0-99.99 wt%. Preferably, the content of the C2-4 alkane is 0-99.99 wt%.

14. The application according to claim 13, wherein, The C2-4 fraction also contains impurities, including C2-4 alkynes and optionally C3 dienes; Preferably, the content of the C2-4 alkyne is 0.01-5 wt%. Preferably, the content of the C3 diene is 0-5 wt%.

15. A method for selective hydrogenation of C2-4 fraction, characterized in that, The method includes: reacting a C2-4 fraction with a selective hydrogenation catalyst under hydrogenation reaction conditions; wherein the selective hydrogenation catalyst is the selective hydrogenation catalyst according to any one of claims 1-7 and 11.

16. The method of claim 20, wherein, The hydrogenation reaction conditions include: using a fixed-bed reactor; a temperature of 20-50℃, preferably 20-25℃; and a pressure of 0.5-0.8MPa, preferably 0.5-0.7MPa. And / or, hydrogen with C 2-4 The molar ratio of the total amount of alkynes to dienes in the fraction is 1-2.5:1, preferably 1.5-2:1; And / or, hydrogen with C 2-4 The total recycle ratio of alkynes to dienes in the fraction is 10-30:1, preferably 20-25:1.

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