C4 fraction selective hydrogenation catalyst as well as preparation method and application thereof

Abstract

The present invention provides a C4 fraction selective hydrogenation catalyst, which comprises a carrier and an active component loaded on the carrier, and the carrier is a metal composite oxide modified by an organic cation quaternary ammonium salt and a silane reagent; the metal composite oxide contains a metal element I, and the metal element I comprises aluminum and titanium; the active component contains a metal element II, the metal element II comprises a main active component copper and an optional auxiliary active component, and the auxiliary active component is selected from at least one of Ni and Ru. The invention also provides a preparation method and application of the C4 fraction selective hydrogenation catalyst, and a method for removing alkyne in C4 fraction and increasing butadiene yield through C4 fraction selective hydrogenation. According to the C4 fraction selective hydrogenation catalyst provided by the invention, the specific carrier, the main active component and the auxiliary active component are matched, so that the obtained C4 fraction selective hydrogenation catalyst has high reaction activity and selectivity, the problem of green oil is solved, and the service life of the catalyst is prolonged.

Description

Technical Field

[0001] This invention relates to the field of selective hydrogenation technology for C4 fractions, and particularly to a selective hydrogenation catalyst for C4 fractions, its preparation method, and its application. Background Technology

[0002] C4 fraction refers to a mixture of various alkanes, alkenes, dienes, and alkynes containing four carbon atoms. It mainly originates from refinery gas produced during petroleum refining and byproducts of ethylene production from petroleum hydrocarbon cracking. Cracked C4 fractions contain saturated and unsaturated hydrocarbons such as n-butane, isobutane, 1-butene, trans-2-butene, cis-2-butene, isobutene, 1,2-butadiene, 1,3-butadiene, methylacetylene, ethylacetylene, and vinylacetylene. Industrially, it is mainly used to produce 1,3-butadiene, isobutene, and 1-butene.

[0003] The C4 fraction produced as a byproduct of high-temperature cracking of hydrocarbons to produce ethylene typically contains 40%-60% butadiene by mass. Butadiene is an important monomer in the synthetic rubber industry. The extraction of butadiene from the C4 fraction usually employs solvent extraction methods, such as the acetonitrile method, the N-methylpyrrolidone method, and the dimethylformamide method. Currently, these methods generally meet the requirements for butadiene purity.

[0004] Due to factors such as cracking depth and cracking technology, the alkyne content in the cracked C4 fraction gradually increases, leading to increased butadiene loss and energy consumption during extraction. Simultaneously, with the development of organic synthesis technology, the restrictions on alkyne content in butadiene have become more stringent. These factors all contribute to decreased economic efficiency of butadiene extraction units. Selectively hydrogenating alkynes during butadiene extraction to recover a portion of the butadiene not only achieves the goal of turning waste into treasure but also plays a crucial role in reducing alkyne emissions and preventing environmental pollution.

[0005] Currently, alkynes in mixed C4 fractions can be removed by catalytic selective hydrogenation. The catalysts used primarily tend to be noble metal catalysts, such as palladium, platinum, and silver, followed by non-noble metal catalysts, such as copper and nickel.

[0006] The selective hydrogenation of alkynes in hydrocarbon streams requires different catalysts and reaction conditions depending on the composition of the feedstock and the desired product. A good selective hydrogenation catalyst, besides possessing high hydrogenation activity, should also exhibit good stability, meaning it should be resistant to impurities and gum deposits to extend its lifespan. Therefore, the support should have low acidity, a small specific surface area, and a large pore size. Furthermore, adding certain promoters during catalyst preparation can also extend the catalyst's lifespan.

[0007] Noble metal catalysts typically employ palladium catalysts supported on a carrier (usually alumina), with the addition of other co-catalyst components such as gold, silver, chromium, copper, iron, rhodium, lithium, potassium, and even lead or zinc. Noble metal catalysts exhibit good low-temperature activity and mild reaction conditions, but their drawbacks include easy loss of active components, high cost, difficulty in regeneration, and slightly poor hydrogenation selectivity. Non-noble metal catalysts require higher temperatures and harsher hydrogenation conditions, but their preparation is simple, they are easy to regenerate repeatedly, and their cost is relatively low, thus still possessing considerable research and development value. In these hydrogenation reactions, semi-hydrogenated free radicals adsorbed on the catalyst react with adjacent alkynes or dienes to form a viscous polymer (commonly known as green oil), mainly composed of compounds with more than six carbon atoms. Because this polymer covers the catalyst surface, it blocks the micropores, reducing catalyst activity and affecting its lifespan. This is especially true for conjugated dienes (such as 1,3-butadiene), whose polymerization reaction is more readily carried out, leading to rapid catalyst deactivation. Therefore, the catalyst must be frequently regenerated for reuse.

[0008] In the application research of selective hydrogenation of C4 alkynes, it has been recognized that nickel-based selective hydrogenation catalysts are safer and more efficient for feedstocks with high alkyne content. However, the activity and selectivity of nickel-based selective hydrogenation catalysts are somewhat inferior to those of noble metal palladium-based catalysts, limiting their application. Therefore, for the selective hydrogenation of C4 alkynes using non-noble metal catalysts, further research is needed to improve the activity and selectivity of these catalysts, address the green oil problem during catalyst use, and extend catalyst life. Using non-noble metal hydrogenation catalysts for the selective hydrogenation of alkynes can improve the catalyst's resistance to impurity poisoning and its stability, which has economic value. Summary of the Invention

[0009] In order to overcome at least one of the above-mentioned problems in the prior art, one of the objectives of the present invention is to provide a C4 fraction selective hydrogenation catalyst with high low-temperature activity, high selectivity and high stability. Compared with precious metal selective hydrogenation catalysts for acetylene removal, the production cost of this catalyst can be reduced by more than 70%, and the catalyst has good resistance to impurity poisoning and good raw material adaptability.

[0010] The second objective of this invention is to provide a method for preparing a selective hydrogenation catalyst for C4 fraction alkynes.

[0011] The third objective of this invention is to provide an application of the above-mentioned selective hydrogenation catalyst for C4 fraction alkynes.

[0012] The fourth objective of this invention is to provide a method for selectively hydrogenating alkynes in C4 fractions to remove alkynes and increase butadiene production.

[0013] Therefore, in a first aspect, the present invention provides a C4 fraction selective hydrogenation catalyst, comprising a support and an active component supported on the support.

[0014] The carrier is a metal composite oxide modified with organic cationic quaternary ammonium salt and silane reagents; the metal composite oxide contains metal element I, which includes aluminum and titanium;

[0015] The active component contains metal element II, which includes the main active component copper and an optional auxiliary active component selected from at least one of Ni and Ru.

[0016] The C4 fraction selective hydrogenation catalyst provided by this invention uses a support treated with an organic cationic quaternary ammonium salt and silane reagents. This treatment solves the problem of low crushing strength in metal composite oxides caused by the introduction of Ti. The support has higher crushing strength, which can effectively prevent pulverization of the catalyst during long-term operation. Furthermore, it can be produced by extrusion, utilizing a shaped surface to increase the contact area between the catalyst's outer surface and physical surfaces, thereby improving catalyst activity. Simultaneously, the modified composite oxide support provided by this invention, through modification with organic cationic quaternary ammonium salts and silane reagents, can further improve the dispersion of active components on the support surface. It can control the particle size of the nanoclusters formed by the active components on the support surface to below 5 nm, thus significantly improving the low-temperature activity of the catalyst.

[0017] The C4 fraction selective hydrogenation catalyst provided by this invention, through the combination of a specific support, main active component and co-active component, has high reactivity and selectivity, solves the green oil problem and extends the catalyst life.

[0018] As a specific embodiment of the present invention, the organic cationic quaternary ammonium salt includes a hydrocarbon-based quaternary ammonium salt.

[0019] As a specific embodiment of the present invention, the general formula of the hydrocarbon-based quaternary ammonium salt is R4N. + X - , where X - Selected from halide ions and acid radical ions, preferably, the halide ions include F. - Cl - ,Br - and I - The acid radical ions include nitrate ions and carboxylate ions, with the general formula R4N. + X -Each R may be the same or different, and each is independently selected from alkyl, cycloalkyl, aryl, aralkyl and alkylaryl. At least one R is selected from alkyl with more than 6 Cs, preferably from alkyl with 6 to 20 Cs, and the remaining Rs are preferably selected from alkyl with 1 to 4 Cs or aralkyl with 7 to 11 Cs.

[0020] As a specific embodiment of the present invention, preferably, the general formula R4N + X - Each R may be the same or different, at least 1 to 2 Rs are selected from C6 or higher alkyl groups, preferably from C6 to C20 alkyl groups, and the remaining Rs are preferably selected from C1 to C4 alkyl groups or C7 to C11 aryl alkyl groups.

[0021] As a specific embodiment of the present invention, the organic cationic quaternary ammonium salt includes at least one of di(octadecyl)dimethyl quaternary ammonium salt, hexadecyltrimethyl quaternary ammonium salt, and C12-18 alkyldimethylbenzyl quaternary ammonium salt.

[0022] As a specific 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.

[0023] As a specific embodiment of the present invention, the general formula of the silane reagent is SiR. 1 x (OR 2 ) y Where x and y are each independently selected from integers from 1 to 3, x + y = 4, R 1 Selected from hydrogen, C1-C6 alkyl and C2-C6 alkenyl, R 2 Selected from C1 to C6 alkyl groups.

[0024] As a specific embodiment of the present invention, the silane reagent includes at least one selected from triethoxysilane, trimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane. The methoxy and ethoxy functional groups in the above-mentioned silane reagents bind to the hydroxyl groups on the support surface, improving the dispersibility of metals and their oxides on the surface and reducing particle size.

[0025] In a specific embodiment of the present invention, the amount of the organic cationic quaternary ammonium salt is 1%-50% of the mass of the metal composite oxide. According to the present invention, controlling the above ratio can increase the hydroxyl groups on the carrier surface and improve the affinity between the carrier surface and the additives.

[0026] In a specific embodiment of the present invention, the amount of the organic cationic quaternary ammonium salt is 30%-50% of the mass of the metal composite oxide. According to the present invention, controlling the above ratio can further increase the hydroxyl groups on the carrier surface and improve the affinity between the carrier surface and the additives.

[0027] In a specific embodiment of the present invention, the amount of the organic cationic quaternary ammonium salt is 35%-50% of the mass of the metal composite oxide. According to the present invention, controlling the above ratio can further increase the hydroxyl groups on the carrier surface and improve the affinity between the carrier surface and the additives.

[0028] In a specific embodiment of the present invention, the amount of the silane reagent is 0.5%-30% of the mass of the metal composite oxide. According to the present invention, controlling the above ratio can increase the hydrophobicity of the support surface and improve the dispersion of the catalyst active component on the support surface.

[0029] In a specific embodiment of the present invention, the amount of the silane reagent is 0.5%-15% of the mass of the metal composite oxide. According to the present invention, controlling the above ratio can further improve the hydrophobicity of the support surface and increase the dispersion of the catalyst active component on the support surface.

[0030] In a specific embodiment of the present invention, the amount of the silane reagent is 0.5%-10% of the mass of the metal composite oxide. According to the present invention, controlling the above ratio can further improve the hydrophobicity of the support surface and increase the dispersion of the catalyst active component on the support surface.

[0031] In a specific embodiment of the present invention, preferably, the carrier is a SiO2-TiO2-Al2O3 composite oxide.

[0032] As a specific embodiment of the present invention, preferably, based on the carrier, the content of TiO2 in the carrier is 5wt% to 25wt%, the content of Al2O3 is 65wt% to 90wt%, and the content of SiO2 is 0.5wt% to 15wt%.

[0033] As a specific embodiment of the present invention, preferably, based on the carrier, the content of Al2O3 in the carrier is 80wt% to 90wt%.

[0034] In a specific embodiment of the present invention, preferably, the metal composite oxide is an Al2O3-TiO2 composite oxide.

[0035] As a specific embodiment of the present invention, based on the TiO2-Al2O3 composite oxide, the content of Ti in the TiO2-Al2O3 composite oxide, calculated as TiO2, is 5wt% to 30wt%; and the content of Al, calculated as Al2O3, is 70wt% to 95wt%. According to the present invention, controlling Al2O3 and TiO2 in the above-mentioned ratio can improve crushing strength, increase specific surface area and pore volume, improve the electronic properties of the catalyst surface, and enhance catalyst activity.

[0036] As a specific embodiment of the present invention, based on the TiO2-Al2O3 composite oxide, the content of Ti in the TiO2-Al2O3 composite oxide, calculated as TiO2, is 8wt% to 25wt%; and the content of Al, calculated as Al2O3, is 75wt% to 92wt%. According to the present invention, controlling Al2O3 and TiO2 in the above-mentioned ratio can further improve the crushing strength, the larger specific surface area and pore volume, improve the electronic properties of the catalyst surface, and enhance the catalyst activity.

[0037] In a specific embodiment of the present invention, preferably, the specific surface area of ​​the carrier is 30-150 μm. 2 / g, preferably 50-90m 2 / g.

[0038] As a specific embodiment of the present invention, preferably, the pore volume of the carrier is 0.2 to 0.8 mL / g, more preferably 0.3 to 0.5 mL / g.

[0039] As a specific embodiment of the present invention, preferably, based on the selective hydrogenation catalyst, the content of the support in the selective hydrogenation catalyst is 70wt% to 95wt%, the content of the main active component is 5wt% to 25wt%, and the content of the co-active component is 0wt% to 5wt%, preferably 0.1wt% to 5wt%.

[0040] In a specific embodiment of the present invention, the active component is distributed on the carrier in the form of nanoclusters, wherein the particle size of the nanoclusters is less than 5 nm.

[0041] As a specific embodiment of the present invention, preferably, in the selective hydrogenation catalyst, the main active component and the co-active component each exist independently in the form of their elemental form or oxide.

[0042] As a specific embodiment of the present invention, preferably, the preparation of the carrier includes the following steps: after the metal composite oxide is subjected to a first treatment with an organic cationic quaternary ammonium salt solution, it is subjected to a second treatment with a silane reagent to obtain the carrier.

[0043] In a preferred embodiment of the present invention, the first treatment includes a first impregnation and a first drying performed sequentially. According to the present invention, using an organic cationic quaternary ammonium salt solution to impregnate the metal composite oxide can effectively control the possibility of metal ions participating in the oxidation reaction.

[0044] As a specific embodiment of the present invention, the second treatment includes adding a solution of silane reagent dropwise to the metal composite oxide after the first treatment, followed by stirring, second drying and first calcination, preferably with a stirring time of 1 min to 60 min.

[0045] As a specific embodiment of the present invention, the solvent of the solution of the organic cationic quaternary ammonium salt includes at least one of water, methanol, ethanol, benzene, toluene, chloroethane, isopropanol, acetone, sulfuric acid, hydrochloric acid, nitric acid, sodium hydroxide, and potassium hydroxide.

[0046] As a specific embodiment of the present invention, the concentration of the organic cation quaternary ammonium salt solution is 0.1 wt% to 10 wt%, preferably 0.2 to 10 wt%, and more preferably 1 to 5 wt%.

[0047] As a specific embodiment of the present invention, preferably, the solution of the silane reagent is an aqueous solution of the silane reagent with a concentration of 0.1-10 wt%, preferably 1-10 wt%.

[0048] As a specific embodiment of the present invention, the conditions for the first impregnation include: impregnation temperature of 10°C to 50°C, and impregnation time of 1 hour to 12 hours, preferably 1 hour to 8 hours.

[0049] As a specific embodiment of the present invention, the conditions for the first drying and the second drying are the same or different, and each independently includes: a drying temperature of 60℃~150℃, preferably 60℃~110℃, and a drying time of 4h~12h.

[0050] As a specific embodiment of the present invention, the conditions for the first roasting include: a roasting temperature of 300-1100°C, preferably 500-900°C, and a roasting time of 4-12 hours.

[0051] Therefore, in a second aspect, the present invention provides a method for preparing the above-mentioned C4 fraction selective hydrogenation catalyst, comprising the following steps: second impregnating the support with a copper salt solution and optionally a nickel salt solution and / or a ruthenium salt solution, followed by a third drying and a second calcination to obtain the catalyst.

[0052] As a specific embodiment of the present invention, the conditions for the second impregnation include: a temperature of 20°C to 70°C, preferably 20°C to 40°C, and a time of 1 hour to 12 hours, preferably 1 hour to 4 hours.

[0053] As a specific embodiment of the present invention, the conditions for the third drying include: a temperature of 60 to 150°C, preferably 100 to 150°C, and a time of 1 to 8 hours, preferably 4 to 8 hours.

[0054] As a specific embodiment of the present invention, the conditions for the second calcination include: a temperature of 300-600°C, preferably 400-500°C, and a time of 4-12 hours.

[0055] As a specific embodiment of the present invention, the copper salt includes at least one of copper sulfate, nitrate, soluble carboxylate, hypophosphite and halide, preferably at least one of copper sulfate, copper nitrate, copper chloride and copper acetate.

[0056] As a specific embodiment of the present invention, the ruthenium salt includes at least one of ruthenium nitrate, soluble carboxylate and halide, preferably at least one of ruthenium nitrate, hydrochloride, oxalate and acetate.

[0057] As a specific embodiment of the present invention, the nickel salt includes at least one of nickel nitrate, soluble carboxylate and halide, preferably at least one of nickel nitrate, hydrochloride, oxalate and acetate.

[0058] As a specific embodiment of the present invention, the copper salt solution, ruthenium salt solution, and nickel salt solution are each independently at least one of water, methanol, ethanol, benzene, toluene, and chloroethane.

[0059] As a specific embodiment of the present invention, preferably, the concentration of the copper salt solution is 0.1 to 0.6 mol / L.

[0060] As a specific embodiment of the present invention, preferably, the concentration of the ruthenium salt solution is 0.005 to 0.01 mol / L.

[0061] As a specific embodiment of the present invention, preferably, the concentration of the nickel salt solution is 0.1 to 0.3 mol / L.

[0062] Therefore, in a third aspect, the present invention provides the application of the above-described C4 fraction selective hydrogenation catalyst or the C4 fraction selective hydrogenation catalyst prepared by the above-described preparation method in the selective hydrogenation removal of alkynes from C4 fractions and the increase in butadiene production.

[0063] As a specific embodiment of the present invention, the conditions for selecting hydrogenation include: reaction temperature of 20℃~40℃, pressure of 0.5MPa~0.8MPa, molar ratio of hydrogen to alkyne of 1~2.5:1, and recycle ratio of 10~30:1.

[0064] According to the catalyst provided by the present invention, the main active component Cu and the co-active component each exist independently in atomic or compound form. Such compounds can be compounds of the main active component Cu and the co-active component commonly used in copper-based catalysts for selective hydrogenation. In some embodiments, the main active component Cu and the co-active component each exist independently in the form of oxides, such as CuO or RuO2.

[0065] Therefore, in a fourth aspect, the present invention provides a method for selectively hydrogenating a C4 fraction to remove alkynes from the C4 fraction and increase butadiene production, comprising: selectively hydrogenating the C4 fraction with hydrogen in the presence of the aforementioned C4 fraction selective hydrogenation catalyst or the C4 fraction selective hydrogenation catalyst prepared by the aforementioned preparation method.

[0066] As a specific embodiment of the present invention, preferably, the conditions for selecting the hydrogenation reaction include: reaction temperature of 20℃~40℃, pressure of 0.5MPa~0.8MPa, molar ratio of hydrogen to alkyne of 1~2.5:1, and recycle ratio of 10~30:1.

[0067] The beneficial effects of this invention are as follows:

[0068] (1) The selective hydrogenation catalyst provided by this invention has a support treated with organic cationic quaternary ammonium salts and silane reagents. This overcomes the disadvantage of low crushing strength caused by the introduction of TiO2 into the support. The resulting catalyst can effectively avoid the pulverization problem that occurs during long-term operation and can be produced by extrusion. The irregular surface increases the contact area between the catalyst's outer surface and the physical environment, thereby improving the catalyst's activity. At the same time, the treatment with organic cationic quaternary ammonium salts and silane reagents can significantly improve the dispersion of active components on the support surface and control the particle size of the nanoclusters formed by the active components on the support surface to below 5 nm, thereby significantly improving the low-temperature activity of the catalyst.

[0069] (2) The catalyst of the present invention has high low-temperature reaction activity 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, which has industrial application value.

[0070] (3) The C4 fraction selective hydrogenation catalyst provided by the present invention has the advantages of high selectivity, high low temperature activity, and stable hydrogenation activity, and can be used for a long period of time. Attached Figure Description

[0071] Figure 1 This is a TEM characterization image of catalyst A. Detailed Implementation

[0072] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0073] (I) Measurement Method

[0074] 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.

[0075] The specific surface area and pore volume 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.

[0076] The contents of Cu, Ni, 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.

[0077] Catalyst characterization methods

[0078] The catalyst was observed using a Jem-3010 high-resolution transmission electron microscope with an accelerating voltage of 200 kV for HR-TEM characterization. Before testing, the catalyst 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 min. Finally, the suspension was continuously added dropwise onto the microgrid using a dropper and allowed to air dry.

[0079] Preparation Example 1

[0080] The selected material is a TiO2-Al2O3 composite oxide produced by Yantai Heng Hui Chemical Co., Ltd., containing 15wt% TiO2 and 85wt% Al2O3, with a specific surface area of ​​60m². 2 / g, pore volume 0.55mL / g.

[0081] 100g of TiO2-Al2O3 composite oxide was impregnated with 1L of a 5wt% dimethyl dioctadecyl ammonium chloride methanol solution for 2h, and then dried at 70℃ for 10h. 100g of a 2wt% vinyltrimethoxysilane aqueous solution was added dropwise to the dried composite oxide. After the addition was completed, the resulting mixture was stirred uniformly for 10 minutes. The mixture was then dried at 70℃ for 10h and calcined at 850℃ for 4h to obtain the modified composite oxide support A'.

[0082] The support A' contains 14.9 wt% TiO2, 84.3 wt% Al2O3, and 0.8 wt% SiO2. The specific surface area of ​​the support is 78 m². 2 / g, pore volume 0.45mL / g, crushing strength 196N / cm. The results are shown in Table 1.

[0083] Preparation Example 2

[0084] The selected material is a TiO2-Al2O3 composite oxide produced by Yantai Heng Hui Chemical Co., Ltd., containing 25wt% TiO2 and 75wt% Al2O3, with a specific surface area of ​​62m². 2 / g, pore volume 0.51mL / g.

[0085] 100g of TiO2-Al2O3 composite oxide was impregnated with 1L of a 5wt% hexadecyltrimethylammonium chloride methanol solution for 2h and then dried at 80℃ for 10h. 100g of a 5wt% triethoxysilane aqueous solution was then added dropwise to the dried composite oxide. After the addition was completed, the resulting mixture was stirred uniformly for 20 minutes. The mixture was then dried at 80℃ for 8h and calcined at 900℃ for 3h to obtain the modified composite oxide support B'.

[0086] The support contains 24.5 wt% TiO2, 73.5 wt% Al2O3, and 2.0 wt% SiO2. The specific surface area of ​​the support is 66 μm. 2 / g, pore volume is 0.41mL / g, and crushing strength is 220N / cm. The results are shown in Table 1.

[0087] Preparation Example 3

[0088] The selected material is a TiO2-Al2O3 composite oxide produced by Yantai Heng Hui Chemical Co., Ltd., containing 12wt% TiO2, 88wt% Al2O3, and a specific surface area of ​​66 μm. 2 / g, pore volume is 0.52mL / g.

[0089] 100g of TiO2-Al2O3 composite oxide was impregnated with 1L of a 5wt% tetradecyl dimethyl benzyl ammonium chloride methanol solution for 2h, and then dried at 90℃ for 9h. 100g of a 2.5wt% methyltriethoxysilane aqueous solution was added dropwise to the dried composite oxide. After the addition was completed, the resulting mixture was stirred evenly for 15 minutes. The composite oxide treated in this way was then dried at 90℃ for 9h and calcined at 750℃ for 6h to obtain the modified composite oxide support C'.

[0090] The support contains 11.9 wt% TiO2, 87.1 wt% Al2O3, and 1.0 wt% SiO2. The specific surface area of ​​the support is 72 μm. 2 / g, pore volume of 0.43mL / g, and crushing strength of 205N / cm. The results are shown in Table 1.

[0091] Preparation Example 4

[0092] The TiO2-Al2O3 composite oxide (TiO2 content 18wt%, Al2O3 content 82wt%, specific surface area 67m) produced by Yantai Heng Hui Chemical Co., Ltd. was selected. 2 / g, pore volume of 0.49mL / g), 100g of TiO2-Al2O3 composite oxide was impregnated with 1L of 5wt% dodecyl dimethyl benzyl ammonium chloride methanol solution for 2h, and then dried at 70℃ for 10h. 100g of 8wt% vinyltrimethoxysilane aqueous solution was added dropwise to the dried composite oxide. After the addition was completed, the resulting mixture was stirred evenly for 30 minutes. The composite oxide treated in this way was then dried at 150℃ for 5h and calcined at 650℃ for 6h to obtain the modified composite oxide support D'.

[0093] The support contains 17.5 wt% TiO2, 79.4 wt% Al2O3, and 3.1 wt% SiO2. The specific surface area of ​​the support is 88 μm. 2 / g, pore volume is 0.44mL / g, and crushing strength is 243N / cm. The results are shown in Table 1.

[0094] Preparation Example 5

[0095] The TiO2-Al2O3 composite oxide (TiO2 content 15wt%, Al2O3 content 85wt%, specific surface area 60m²) produced by Yantai Heng Hui Chemical Co., Ltd. was selected.2 / g, pore volume 0.55mL / g, crushing strength 160N / cm), 100g of TiO2-Al2O3 composite oxide was impregnated with 1L of 5wt% hexadecyltrimethylammonium chloride methanol solution for 2h, and then dried at 60℃ for 12h. 100g of 1wt% vinyltrimethoxysilane aqueous solution was added dropwise to the dried composite oxide. After the addition was completed, the resulting mixture was stirred evenly for 20 minutes. The composite oxide treated in this way was then dried at 60℃ for 12h and calcined at 850℃ for 4h to obtain the modified composite oxide support E'.

[0096] The support contains 14.9 wt% TiO2, 84.7 wt% Al2O3, and 0.4 wt% SiO2. The specific surface area of ​​the support is 77 μm. 2 / g, pore volume 0.47mL / g, crushing strength 186N / cm. The results are shown in Table 1.

[0097] Preparation Example 6

[0098] The TiO2-Al2O3 composite oxide (TiO2 content 8wt%, Al2O3 content 92wt%, specific surface area 63m) produced by Yantai Heng Hui Chemical Co., Ltd. was selected. 2 / g, pore volume of 0.54mL / g), 100g of TiO2-Al2O3 composite oxide was impregnated with 1L of 5wt% octadecyl dimethyl benzyl ammonium chloride methanol solution for 2h, and then dried at 110℃ for 7h. 100g of 0.5wt% vinyltrimethoxysilane aqueous solution was added dropwise to the dried composite oxide. After the addition was completed, the resulting mixture was stirred evenly for 10 minutes. The composite oxide treated in this way was then dried at 110℃ for 7h and calcined at 850℃ for 4h to obtain the modified composite oxide support F'.

[0099] The support contains 8.0 wt% TiO2, 91.8 wt% Al2O3, and 0.2 wt% SiO2. The specific surface area of ​​the support is 88 μm. 2 / g, pore volume is 0.44mL / g, and crushing strength is 243N / cm. The results are shown in Table 1.

[0100] Comparative Preparation Example 1

[0101] The TiO2-Al2O3 carrier (TiO2 content 15wt%, Al2O3 content 85wt%, specific surface area 60m²) produced by Yantai Heng Hui Chemical Co., Ltd. was selected. 2 The material (g, pore volume 0.55 mL / g, crushing strength 160 N / cm) was not modified and was denoted as carrier G'. The results are shown in Table 1.

[0102] Comparative Preparation Example 2

[0103] γ-Al2O3 support (specific surface area 140m²) produced by Yantai Heng Hui Chemical Co., Ltd. was selected. 2 The material (with a pore volume of 0.65 mL / g and a crushing strength of 300 N / cm) was not modified and was denoted as carrier H'. The results are shown in Table 1.

[0104] Comparative preparation example 3

[0105] The TiO2-Al2O3 composite oxide (TiO2 content 15wt%, Al2O3 content 85wt%, specific surface area 60m²) produced by Yantai Heng Hui Chemical Co., Ltd. was selected. 2 / g, pore volume 0.55mL / g, crushing strength 160N / cm) 100g, 2wt% vinyltrimethoxysilane aqueous solution 100g was added dropwise to the composite oxide. After the addition was completed, the resulting mixture was stirred evenly for 10 minutes. The composite oxide treated in this way was then dried at 70℃ for 10h and calcined at 850℃ for 4h to obtain modified composite oxide carrier I'.

[0106] The support contains 15.0 wt% TiO2, 84.6 wt% Al2O3, and 0.4 wt% SiO2. The specific surface area of ​​the support is 75 μm. 2 / g, pore volume 0.40mL / g, crushing strength 178N / cm. The results are shown in Table 1.

[0107] Comparative preparation example 4

[0108] The TiO2-Al2O3 composite oxide (TiO2 content 15wt%, Al2O3 content 85wt%, specific surface area 60m²) produced by Yantai Heng Hui Chemical Co., Ltd. was selected. 2 / g, pore volume 0.55mL / g, crushing strength 160N / cm), 100g of TiO2-Al2O3 composite oxide was impregnated with 1L of 5wt% dimethyl dioctadecyl ammonium chloride methanol solution. After impregnation for 2h, it was dried at 70℃ for 10h and calcined at 850℃ for 4h to obtain the modified composite oxide carrier J'.

[0109] The support contains 15 wt% TiO2 and 85 wt% Al2O3. The specific surface area of ​​the support is 81 μm. 2 / g, pore volume is 0.49mL / g, and crushing strength is 168N / cm. The results are shown in Table 1.

[0110] Table 1

[0111]

[0112]

[0113] As shown in Table 1, the modified composite oxide provided by the present invention overcomes the disadvantage of low crushing strength caused by the introduction of TiO2 in metal composite oxides through modification, and significantly improves the crushing strength of the modified composite oxide.

[0114] Example 1

[0115] 74.8 g of the modified composite oxide support prepared in Preparation Example 1 was added to 628 mL of 0.5 mol / L copper nitrate solution and impregnated at 25 °C for 2 h. After filtration, the filter cake was dried at 110 °C for 8 h. The dried filter cake was then added to 150 mL of ruthenium nitrate solution with a Ru content of 0.01 mol / L and impregnated at 25 °C for 2 h. After drying at 110 °C for 8 h, the solution was calcined at 550 °C for 6 h to obtain the Cu-Ru / SiO2-TiO2-Al2O3 catalyst (supported catalyst A).

[0116] Example 2

[0117] 81.7 g of the modified composite oxide support prepared in Preparation Example 2 was added to 453 mL of 0.5 mol / L copper nitrate solution and impregnated at 25 °C for 2 h. After filtration, the filter cake was dried at 110 °C for 8 h. The dried filter cake was then added to 225 mL of ruthenium nitrate solution with a Ru content of 0.01 mol / L and impregnated at 25 °C for 2 h. After drying at 110 °C for 8 h, the filter cake was calcined at 550 °C for 6 h to obtain Cu-Ru / SiO2-TiO2-Al2O3 catalyst (supported catalyst B).

[0118] Example 3

[0119] 85.6 g of the modified composite oxide support prepared in Preparation Example 3 was added to 440 mL of 0.4 mol / L copper nitrate solution and impregnated at 25 °C for 2 h. After filtration, the filter cake was dried at 110 °C for 8 h. The dried filter cake was then added to 300 mL of ruthenium nitrate solution with a Ru content of 0.01 mol / L and impregnated at 25 °C for 2 h. After drying at 110 °C for 8 h, the solution was calcined at 550 °C for 6 h to obtain the Cu-Ru / SiO2-TiO2-Al2O3 catalyst (supported catalyst C).

[0120] Example 4

[0121] 79.7 g of the modified composite oxide support prepared in Preparation Example 4 was added to 503 mL of 0.5 mol / L copper nitrate solution and impregnated at 25 °C for 2 h. After filtration, the filter cake was dried at 110 °C for 8 h. The dried filter cake was then added to 225 mL of ruthenium nitrate solution with a Ru content of 0.01 mol / L and impregnated at 25 °C for 2 h. After drying at 110 °C for 8 h, it was calcined at 550 °C for 6 h to obtain the Cu-Ru / SiO2-TiO2-Al2O3 catalyst (supported catalyst D).

[0122] Example 5

[0123] 94.5 g of the modified composite oxide support prepared in Preparation Example 5 was added to 419 mL of 0.15 mol / L copper nitrate solution and impregnated at 25 °C for 2 h. After filtration, the filter cake was dried at 110 °C for 8 h. The dried filter cake was then added to 375 mL of ruthenium nitrate solution with a Ru content of 0.01 mol / L and impregnated at 25 °C for 2 h. After drying at 110 °C for 8 h, the solution was calcined at 550 °C for 6 h to obtain the Cu-Ru / SiO2-TiO2-Al2O3 catalyst (supported catalyst E).

[0124] Example 6

[0125] 74.9 g of the modified composite oxide support prepared in Preparation Example 6 was added to 628 mL of 0.5 mol / L copper nitrate solution, impregnated at 25 °C for 2 h, filtered, and the filter cake was dried at 110 °C for 8 h; the dried filter cake was added to 150 mL of ruthenium nitrate with a Ru content of 0.005 mol / L, impregnated at 25 °C for 2 h, dried at 110 °C for 8 h, and then calcined at 550 °C for 6 h to obtain Cu-Ru / SiO2-TiO2-Al2O3 catalyst (supported catalyst F).

[0126] Comparative Examples 1-4

[0127] 74.8 g of the support from Comparative Preparation Examples 1-4 was added to 628 mL of 0.5 mol / L copper nitrate solution, impregnated at 25 °C for 2 h, filtered, and the filter cake was dried at 110 °C for 8 h. The dried filter cake was then added to 150 mL of ruthenium nitrate solution with a Ru content of 0.01 mol / L, impregnated at 25 °C for 2 h, dried at 110 °C for 8 h, and then calcined at 550 °C for 6 h to obtain catalysts G-J.

[0128] The catalyst supports prepared in each embodiment and comparative example are shown in Table 2 (based on a catalyst mass of 100 parts).

[0129] Table 2

[0130]

[0131] Application Example 1

[0132] In this embodiment, a fixed-bed pilot-scale evaluation device from Tuochuan Scientific Equipment Co., Ltd. was used, loaded with 50 mL of catalyst, to conduct a selective hydrogenation reaction of butadiene extraction tail gas. The composition of the butadiene extraction tail gas is shown in Table 3.

[0133] Select the following hydrogenation reaction conditions: reaction pressure of 0.5 to 0.7 MPa, hydrogen flow rate of 1.92 L / h, reactor inlet temperature of 25 °C, recycle ratio of 20:1, and feed rate of 25 mL / h.

[0134] Catalyst AH was evaluated under the same conditions, and the results of hydrogenation and alkyne removal are shown in Table 4.

[0135] Table 3. Composition of butadiene extraction tail gas

[0136] Serial Number composition wt% 1 Isobutane 2.658 2 n-Butane 5.652 3 trans-2-butene 5.994 4 n-Butene 24.635 5 Isobutylene 31.445 6 cis-2-butene 2.986 7 1,3-Butadiene 3.162 8 1,2-Butadiene 0 9 Vinylacetylene (VA) 20.563 10 Ethylacetylene (EA) 2.344

[0137] Table 4 Results of selective hydrogenation of butadiene extraction tail gas

[0138] catalyst Vinylacetylene conversion rate 1,3-Butadiene selectivity* (%) A 80.72 55 B 83.71 46 C 81.3 45.68 D 80.23 41.9 E 76.32 43.96 F 19.68 48 G 70.3 38.6 H 60.34 33.2 I 73.53 42.5 J 76.78 43.1

[0139] In Table 4, the selectivity of 1,3-butadiene* = (1,3-butadiene in the product - 1,3-butadiene in the feedstock) / (vinylacetylene in the feedstock - vinylacetylene in the product).

[0140] As can be seen from the table above, the catalyst provided by this invention exhibits a high conversion rate of vinylacetylene and a high selectivity for 1,3-butadiene. Because the vinylacetylene in the hydrogenation product can be controlled within a low range, the hydrogenation product can be directly returned to the extraction system to achieve increased butadiene production.

[0141] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A selective hydrogenation catalyst for C4 fractions, characterized in that, Includes the carrier and the active components loaded on the carrier. The carrier is a metal composite oxide modified with organic cationic quaternary ammonium salt and silane reagents; the metal composite oxide contains metal element I, which includes aluminum and titanium; The active component contains metal element II, which includes the main active component copper and an optional auxiliary active component selected from at least one of Ni and Ru.

2. The catalyst according to claim 1, characterized in that, The organic cationic quaternary ammonium salt includes a hydrocarbon-based quaternary ammonium salt, preferably, the hydrocarbon-based quaternary ammonium salt has the general formula R4N. + X - , where X - Selected from halide ions and acid radical ions, preferably, the halide ions include F. - Cl - ,Br - and I - The acid radical ions include nitrate ions and carboxylate ions, with the general formula R4N. + X - Each R in the R may be the same or different, and each is independently selected from alkyl, cycloalkyl, aryl, aralkyl and alkylaryl, with at least one R, preferably 1 to 2 Rs selected from alkyl groups of C6 or above, preferably from C6 to C20 alkyl groups, and the remaining Rs are preferably selected from C1 to C4 alkyl groups and C7 to C11 aralkyl groups; Preferably, the organic cationic quaternary ammonium salt includes at least one of bis(octadecyldimethyl)quaternary ammonium salt, hexadecyltrimethyl)quaternary ammonium salt, and C12-18 alkyldimethylbenzyl)quaternary ammonium salt; More preferably, the organic cationic quaternary ammonium salt is selected from at least one of dioctadecyl 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 general formula of the silane reagent is SiR 1 x (OR 2 ) y Where x and y are each independently selected from integers from 1 to 3, x + y = 4, R 1 Selected from hydrogen, C1-C6 alkyl and C2-C6 alkenyl, R 2 Selected from C1 to C6 alkyl groups; Preferably, the silane reagent comprises at least one of triethoxysilane, trimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane; and / or The amount of the organic cationic quaternary ammonium salt is 1%-50% of the mass of the metal composite oxide, preferably 30%-50%, more preferably 35%-50%; and / or The amount of the silane reagent used is 0.5%-30% of the mass of the metal composite oxide, preferably 0.5%-15%, and more preferably 0.5%-10%.

3. The catalyst according to claim 1 or 2, characterized in that, The support is a SiO2-TiO2-Al2O3 composite oxide. Preferably, based on the support, the content of TiO2 in the support is 5wt% to 25wt%, the content of Al2O3 is 65wt% to 90wt%, more preferably 80wt% to 90wt%, and the content of SiO2 is 0.5wt% to 15wt%; and / or The metal composite oxide is an Al2O3-TiO2 composite oxide; preferably, based on the TiO2-Al2O3 composite oxide, the Ti content in the TiO2-Al2O3 composite oxide, calculated as TiO2, is 5wt% to 30wt%, more preferably 8wt% to 25wt%; the Al content, calculated as Al2O3, is 70wt% to 95wt%, more preferably 75wt% to 92wt%; and / or The specific surface area of ​​the carrier is 30–150 μm. 2 / g, preferably 50-90m 2 / g; and / or The pore volume of the carrier is 0.2 to 0.8 mL / g, preferably 0.3 to 0.5 mL / g.

4. The catalyst according to any one of claims 1-3, characterized in that, Based on the selective hydrogenation catalyst, the content of the support in the selective hydrogenation catalyst is 70 wt% to 95 wt%, the content of the main active component is 5 wt% to 25 wt%, and the content of the co-active component is 0 wt% to 5 wt%, preferably 0.1 wt% to 5 wt%; and / or The active component is distributed on the support in the form of nanoclusters, wherein the particle size of the nanoclusters is less than 5 nm; and / or In the selective hydrogenation catalyst, the main active component and the co-active component each exist independently in the form of their elemental form or oxide.

5. The catalyst according to any one of claims 1-4, characterized in that, The preparation of the carrier includes the following steps: The metal composite oxide was first treated with an organic cationic quaternary ammonium salt solution, and then treated with a silane reagent to obtain the carrier. Preferably, the first treatment includes a first impregnation and a first drying performed sequentially; and / or, the second treatment includes adding a solution of a silane reagent dropwise to the first-treated metal composite oxide, followed by stirring, a second drying, and a first calcination, preferably with a stirring time of 1 min to 60 min; Preferably, the solvent of the organic cationic quaternary ammonium salt solution includes at least one selected from water, methanol, ethanol, benzene, toluene, chloroethane, isopropanol, acetone, sulfuric acid, hydrochloric acid, nitric acid, sodium hydroxide, and potassium hydroxide. Preferably, the concentration of the organic cation quaternary ammonium salt solution is 0.1 wt% to 10 wt%, more preferably 0.2 to 10 wt%, and even more preferably 1 to 5 wt%. Preferably, the solution of the silane reagent is an aqueous solution of the silane reagent with a concentration of 0.1-10 wt%, more preferably 1-10 wt%. Preferably, the conditions for the first impregnation include: an impregnation temperature of 10°C to 50°C and an impregnation time of 1 hour to 12 hours, preferably 1 hour to 8 hours; Preferably, the conditions for the first and second drying are the same or different, and each independently includes: a drying temperature of 60℃~150℃, preferably 60℃~110℃, and a drying time of 4h~12h; and / or The conditions for the first roasting include: a roasting temperature of 300–1100℃, preferably 500–900℃, and a roasting time of 4–12 hours.

6. A method for preparing a C4 fraction selective hydrogenation catalyst according to any one of claims 1-5, characterized in that, Includes the following steps: The support is second-impregnated with a copper salt solution and optionally a nickel salt solution and / or a ruthenium salt solution, followed by a third drying and a second calcination to obtain the catalyst.

7. The preparation method according to claim 6, characterized in that, The conditions for the second impregnation include: a temperature of 20°C to 70°C, preferably 20°C to 40°C, and a time of 1 hour to 12 hours, preferably 1 hour to 4 hours; and / or The conditions for the third drying include: a temperature of 60–150°C, preferably 100–150°C, and a time of 1–8 hours, preferably 4–8 hours; and / or The conditions for the second roasting include: a temperature of 300–600°C, preferably 400–500°C, and a time of 4–12 hours.

8. The preparation method according to claim 6 or 7, characterized in that, The copper salt includes at least one of copper sulfate, nitrate, soluble carboxylate, hypophosphite, and halide, preferably at least one of copper sulfate, copper nitrate, copper chloride, and copper acetate; and / or The ruthenium salt includes at least one of ruthenium nitrate, soluble carboxylate, and halide, preferably at least one of ruthenium nitrate, hydrochloride, oxalate, and acetate; and / or The nickel salt includes at least one of nickel nitrate, soluble carboxylate, and halide, preferably at least one of nickel nitrate, hydrochloride, oxalate, and acetate; and / or The copper salt solution, ruthenium salt solution, and nickel salt solution are each independently at least one of water, methanol, ethanol, benzene, toluene, and chloroethane; and / or The concentration of the copper salt solution is 0.1–0.6 mol / L; and / or The concentration of the ruthenium salt solution is 0.005–0.01 mol / L; and / or The concentration of the nickel salt solution is 0.1–0.3 mol / L.

9. The application of the C4 fraction selective hydrogenation catalyst according to any one of claims 1-5 or the C4 fraction selective hydrogenation catalyst prepared by any one of claims 6-8 in the selective hydrogenation removal of alkynes from C4 fractions and the increase in butadiene production, preferably, the selective hydrogenation conditions include: The reaction temperature is 20℃~40℃, the pressure is 0.5MPa~0.8MPa, the molar ratio of hydrogen to alkyne is 1~2.5:1, and the recycle ratio is 10~30:

1.

10. A method for selectively hydrogenating a C4 fraction to remove alkynes and increase butadiene production, comprising: The C4 fraction and hydrogen are selectively hydrogenated in the presence of the C4 fraction selective hydrogenation catalyst according to any one of claims 1-5 or the C4 fraction selective hydrogenation catalyst prepared by any one of claims 6-8. Preferably, the conditions for the selective hydrogenation reaction include: reaction temperature of 20°C to 40°C, pressure of 0.5 MPa to 0.8 MPa, molar ratio of hydrogen to alkyne of 1 to 2.5:1, and recycle ratio of 10 to 30:1.

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