Catalyst for selective hydrogenation and isomerization of monoolefine as well as preparation method and application of catalyst

Abstract

The present invention provides a catalyst for selective hydrogenation and isomerization of monoolefine, the catalyst 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, and the metal element II comprises a main active component molybdenum and an optional auxiliary active component Ni. According to the catalyst provided by the invention, the carrier is treated by the organic cation quaternary ammonium salt and the silane reagent, and dispersion of active components on the surface of the carrier can be remarkably improved, so that the low-temperature activity of the catalyst prepared from the carrier is remarkably improved. The invention also provides a preparation method and application of the catalyst for selective hydrogenation and isomerization of monoolefine, and a method for removing alkyne in C4 fraction and increasing butadiene yield through selective hydrogenation of C4 fraction alkyne.

Description

Technical Field

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

[0002] With the rapid expansion of refining capacity, FCCs generate a considerable amount of C4 byproducts through hydrocarbon steam cracking. This valuable resource is mostly processed cheaply as liquefied petroleum gas (LPG). Butene alkylation can effectively utilize this feedstock to produce high-quality C4 alkylated gasoline. In this process, isobutane and butene are reacted with sulfuric acid and hydrofluoric acid to form a mixture of isoalkanes, an ideal blending component for high-octane gasoline. It has a moderate saturated vapor pressure, is free of olefins, sulfur, benzene, and aromatic compounds, and is clean.

[0003] With increasing environmental awareness, there is an urgent need to reduce or eliminate the use of gasoline additive MTBE, leading to a growing demand for high-octane gasoline. This underscores the increasing importance of alkylation processes, necessitating expanded production and improved alkylation technology. Alkylation feedstocks from steam cracking and FCC processes typically contain 0.2%–2.0% butadiene. Selective hydrogenation is essential to remove butadiene, thereby reducing sulfuric acid consumption, decreasing acid solvent generation, effectively lowering the dry point of alkylate, and minimizing economic losses due to acid corrosion of equipment. Simultaneously, approximately 70% of 1-butene isomerizes to 2-butene, increasing the octane number of the alkylate (2-butene alkylate has an octane number 2–3 units higher than 1-butene alkylate).

[0004] In a mixed feedstock containing isobutane, n-butane, trans-butene, n-butene, isobutene, cis-butene, and butadiene, hydrogenation removes butadiene while isomerizing 1-butene to 2-butene. This process typically uses noble metal catalysts, such as Pd catalysts, with catalyst supports including Al₂O₃ and SiO₂, employing a liquid-phase fixed-bed hydrogenation reaction. Existing alkylation feedstock pretreatment technologies all utilize supported noble metal catalysts. However, due to the high cost of noble metals, this results in high catalyst costs. Furthermore, Pd itself is highly reactive, a major cause of unsaturated hydrocarbon oligomerization, leading to significant butene hydrogenation losses. Butadiene polymerization further reduces catalyst activity. Additionally, noble metal catalysts exhibit poor resistance to impurities such as sulfur, affecting stability. Currently, the main problems with noble metal catalysts in this field are low isomerization rates, high butene hydrogenation losses, a high proportion of polymerization reactions, and poor catalyst stability. Summary of the Invention

[0005] 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 catalyst for selective hydrogenation and isomerization of monoolefins. This catalyst is a non-precious metal catalyst with high isomerization selectivity and high stability. Compared with precious metal selective hydrogenation and alkyne removal catalysts, the investment cost of this catalyst can be reduced by more than 80%, and it has better resistance to impurity poisoning and stability.

[0006] The second objective of this invention is to provide a method for preparing a catalyst for selective hydrogenation and isomerization of monoolefins, which has the advantages of convenient preparation and good hydrogenation activity of the obtained catalyst.

[0007] A third objective of this invention is to provide an application of the above-described catalyst for selective hydrogenation and isomeric monoolefins or the catalyst for selective hydrogenation and isomeric monoolefins prepared by the above-described preparation method.

[0008] 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.

[0009] Therefore, in a first aspect, the present invention provides a catalyst for selective hydrogenation and isomerization of monoolefins, comprising a support and an active component supported on the support.

[0010] 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;

[0011] The active component contains metal element II, which includes the main active component molybdenum and the optional auxiliary active component Ni.

[0012] The catalyst provided by this invention has a support modified with organic cationic quaternary ammonium salt and silane reagents, which solves the problem of low crushing strength of metal composite oxides caused by the introduction of Ti. The support has higher crushing strength, which can effectively avoid the pulverization problem of the catalyst during long-term operation. It can also 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.

[0013] The catalyst provided by this invention has a support modified with organic cationic quaternary ammonium salt and silane reagents, which 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 prepared by the support. Through the combination of specific support, main active component and co-active component, the catalyst obtained has high reactivity, selectivity and stability.

[0014] As a specific embodiment of the present invention, the organic cationic quaternary ammonium salt includes a hydrocarbon-based quaternary ammonium salt.

[0015] 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.

[0016] As a specific embodiment of the present invention, the general formula R4N + X - The Rs 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.

[0017] 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-C18 alkyldimethylbenzyl quaternary ammonium salt.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] As a specific embodiment of the present invention, the metal composite oxide is an Al2O3-TiO2 composite oxide.

[0028] As a specific embodiment of the present invention, based on the Al2O3-TiO2 composite oxide, the content of Ti in the Al2O3-TiO2 composite oxide, calculated as TiO2, is 5-30 wt%; and the content of Al, calculated as Al2O3, is 70 wt%-95 wt%. 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.

[0029] As a specific embodiment of the present invention, based on the Al2O3-TiO2 composite oxide, the content of Ti in the Al2O3-TiO2 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.

[0030] In a specific embodiment of the present invention, the carrier is a SiO2-TiO2-Al2O3 composite oxide.

[0031] As a specific embodiment of the present invention, based on the carrier, the content of Ti in the carrier, calculated as TiO2, is 5wt% to 25wt%, the content of Al, calculated as Al2O3, is 65wt% to 90wt%, preferably 80wt% to 90wt%, and the content of Si, calculated as SiO2, is 0.5wt% to 15wt%.

[0032] As a specific embodiment of the present invention, based on 100 parts by mass of catalyst, the content of the main active component Mo in the catalyst is 5 to 25 parts, calculated as MoO, the content of the auxiliary active component Ni is 0 to 5 parts, preferably 0.1 to 5 parts, calculated as its oxide, and the content of the support is 70 to 95 parts.

[0033] 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.

[0034] In a specific embodiment of the present invention, the specific surface area of ​​the carrier is 30–150 μm. 2 / g, preferably 50-90m 2 / g.

[0035] As a specific embodiment of the present invention, the pore volume of the carrier is 0.2 to 0.8 mL / g, preferably 0.3 to 0.5 mL / g.

[0036] As a specific embodiment of the present invention, the main active component and the auxiliary active component each exist independently in the form of their elemental form or oxide.

[0037] As a specific embodiment of the present invention, 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.

[0038] In a specific 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.

[0039] 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.

[0040] 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%.

[0041] 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, isopropanol, acetone, sulfuric acid, hydrochloric acid, nitric acid, sodium hydroxide, and potassium hydroxide.

[0042] As a specific embodiment of the present invention, 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%.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] Therefore, in a second aspect, the present invention provides a method for preparing the above-mentioned catalyst for selective hydrogenation and isomerization of monoolefins, comprising the following steps: second impregnating a support with a molybdenum salt solution and optionally a nickel salt solution, and third drying and second calcining the impregnated support to obtain the catalyst.

[0047] As a specific embodiment of the present invention, the molybdenum salt includes at least one of molybdenum sulfate, nitrate, soluble carboxylate, hypophosphite and halide, preferably at least one of molybdenum sulfate, molybdenum nitrate, molybdenum chloride and molybdenum acetate.

[0048] 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.

[0049] As a specific embodiment of the present invention, the molybdenum salt solution and the nickel salt solution are each independently at least one of water, methanol, ethanol, benzene, toluene, and chloroethane.

[0050] As a specific embodiment of the present invention, preferably, the concentration of the molybdenum salt solution is 0.1 to 0.6 mol / L.

[0051] As a specific embodiment of the present invention, preferably, the concentration of the nickel salt solution is 0.05 to 0.3 mol / L.

[0052] As a specific embodiment of the present invention, the conditions for the second impregnation include: temperature of 20°C to 70°C, preferably 20°C to 40°C, and 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 60-150°C, preferably 100-150°C, and a time of 1-8 hours, preferably 4-8 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] Therefore, in a third aspect, the present invention provides the application of the above-described selectively hydrogenated and isomerized monoolefin catalyst or the selectively hydrogenated and isomerized monoolefin catalyst prepared by the above-described preparation method in the selective hydrogenation removal of alkynes from C4 fractions and the increase in butadiene production.

[0056] In a preferred embodiment of the present invention, the conditions for selecting hydrogenation include: a reaction temperature of 40°C to 120°C, a pressure of 0.5 MPa to 3.0 MPa, a hydrogen flow rate to fresh feed volume ratio of 10 to 300:1, and a feed volume hourly space velocity of 0.1 to 2.0 h⁻¹.-1 .

[0057] Therefore, in a fourth aspect, the present invention provides a method for selectively hydrogenating alkynes in a C4 fraction to remove alkynes and increase butadiene production, wherein the C4 fraction and hydrogen are selectively hydrogenated in the presence of the catalyst described above for selective hydrogenation and isomerization of mono-olefins or the catalyst prepared by the above preparation method for selective hydrogenation and isomerization of mono-olefins.

[0058] As a specific embodiment of the present invention, preferably, the conditions for selecting the hydrogenation reaction include: a reaction temperature of 40℃~120℃, a pressure of 0.5MPa~3.0MPa, a hydrogen flow rate to fresh feed volume ratio of 10~300:1, and a feed volume hourly space velocity of 0.1~2.0h. -1 .

[0059] The beneficial effects of this invention are as follows:

[0060] (1) The selective hydrogenation catalyst provided by the present invention has a support modified by organic cationic quaternary ammonium salt and silane reagent, which can significantly improve the dispersion of active components on the support surface and control the atomic clusters to below 5 nm, thereby significantly improving the low-temperature activity of the catalyst prepared by the support; the catalyst obtained by the combination of specific support, main active component and co-active component has high reactivity, selectivity and stability.

[0061] (2) The selective hydrogenation catalyst provided by the present invention has a support modified by organic cationic quaternary ammonium salt and silane reagents, which solves the problem of low crushing strength of metal composite oxides caused by the introduction of Ti. The support has higher crushing strength, which can effectively avoid the pulverization problem of the catalyst during long-term operation. It can also 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.

[0062] (3) The non-precious metal 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.

[0063] (4) The non-precious metal 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

[0064] Figure 1 This is a TEM characterization image of catalyst A. Detailed Implementation

[0065] 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.

[0066] 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.

[0067] 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.

[0068] The Mo and Ni contents in the catalyst were determined using an ICP atomic emission spectrometer, following 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.

[0069] Catalyst characterization methods

[0070] 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.

[0071] In this invention:

[0072]

[0073] Preparation Example 1

[0074] 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.

[0075] 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'.

[0076] 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.

[0077] Preparation Example 2

[0078] 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.

[0079] 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'.

[0080] 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.

[0081] Preparation Example 3

[0082] 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.

[0083] 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'.

[0084] 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.

[0085] Preparation Example 4

[0086] 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'.

[0087] 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.

[0088] Preparation Example 5

[0089] 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'.

[0090] 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.

[0091] Preparation Example 6

[0092] 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'.

[0093] 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.

[0094] Comparative Preparation Example 1

[0095] The TiO2-Al2O3 carrier (TiO2 content 15wt%, Al2O3 content 85wt%, specific surface area 60m²) produced by Yantai Heng Hui Chemical Co., Ltd. was selected. 2The 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.

[0096] Comparative Preparation Example 2

[0097] 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.

[0098] Comparative preparation example 3

[0099] 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'.

[0100] 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.

[0101] Comparative preparation example 4

[0102] 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'.

[0103] 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.

[0104] Table 1

[0105]

[0106]

[0107]

[0108] 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.

[0109] Example 1

[0110] 78 g of the modified composite oxide support prepared in Preparation Example 1 was added to 500 mL of an aqueous solution of ammonium molybdate heptahydrate with a Mo content of 0.21 mol / L and nickel nitrate with a Ni content of 0.21 mol / L. The solution was impregnated at 25 °C for 180 minutes, dried at 110 °C for 6 hours, and then calcined at 550 °C for 4 hours to obtain the Mo-Ni / SiO2-TiO2-Al2O3 catalyst (supported catalyst A).

[0111] Example 2

[0112] 77 g of the modified composite oxide support prepared in Preparation Example 2 was added to 500 mL of an aqueous solution of ammonium molybdate heptahydrate with a Mo content of 0.25 mol / L and nickel nitrate with a Ni content of 0.13 mol / L. The solution was impregnated at 25 °C for 180 minutes, dried at 110 °C for 6 hours, and then calcined at 550 °C for 4 hours to obtain the Mo-Ni / SiO2-TiO2-Al2O3 catalyst (supported catalyst B).

[0113] Example 3

[0114] 80 g of the modified composite oxide support prepared in Preparation Example 3 was added to 500 mL of an aqueous solution of ammonium molybdate heptahydrate with a Mo content of 0.19 mol / L and nickel nitrate with a Ni content of 0.16 mol / L. The solution was impregnated at 25 °C for 180 minutes, dried at 110 °C for 6 hours, and then calcined at 550 °C for 4 hours to obtain the Mo-Ni / SiO2-TiO2-Al2O3 catalyst (supported catalyst C).

[0115] Example 4

[0116] 77 g of the modified composite oxide support prepared in Preparation Example 4 was added to 500 mL of an aqueous solution of ammonium molybdate heptahydrate with a Mo content of 0.28 mol / L and nickel nitrate with a Ni content of 0.08 mol / L. The solution was impregnated at 25 °C for 180 minutes, dried at 110 °C for 6 hours, and then calcined at 550 °C for 4 hours to obtain the Mo-Ni / SiO2-TiO2-Al2O3 catalyst (supported catalyst D).

[0117] Example 5

[0118] 85 g of the modified composite oxide support prepared in Preparation Example 5 was added to 300 mL of an aqueous solution of ammonium molybdate heptahydrate with a Mo content of 0.12 mol / L and nickel nitrate with a Ni content of 0.27 mol / L. The solution was impregnated at 25 °C for 180 minutes, dried at 110 °C for 6 hours, and then calcined at 550 °C for 4 hours to obtain the Mo-Ni / SiO2-TiO2-Al2O3 catalyst (supported catalyst E).

[0119] Example 6

[0120] 78 g of the modified composite oxide support prepared in Preparation Example 6 was added to 500 mL of an aqueous solution of ammonium molybdate heptahydrate with a Mo content of 0.21 mol / L and nickel nitrate with a Ni content of 0.21 mol / L. The solution was impregnated at 25 °C for 180 minutes, dried at 110 °C for 6 hours, and then calcined at 550 °C for 4 hours to obtain the Mo-Ni / SiO2-TiO2-Al2O3 catalyst (supported catalyst F).

[0121] Comparative Examples 1-2

[0122] 78 g of the support from Comparative Preparation Examples 1-2 was added to 500 mL of an aqueous solution of ammonium molybdate heptahydrate with a Mo content of 0.21 mol / L and nickel nitrate with a Ni content of 0.21 mol / L. The solution was impregnated at 25 °C for 180 minutes, dried at 110 °C for 6 hours, and then calcined at 550 °C for 4 hours to obtain catalysts G and H.

[0123] Comparative Examples 3-4

[0124] 85g of the support from Comparative Preparation Examples 3-4 was added to 300mL of an aqueous solution of ammonium molybdate heptahydrate with a Mo content of 0.12mol / L and nickel nitrate with a Ni content of 0.27mol / L. The solution was impregnated at 25°C for 180 minutes, dried at 110°C for 6 hours, and then calcined at 550°C for 4 hours to obtain catalysts I and J.

[0125] The catalysts prepared in each embodiment and comparative example are shown in Table 2.

[0126] Table 2

[0127]

[0128] Supported catalyst A was characterized using the catalyst characterization methods described above. Figure 1 ,from Figure 1 It can be seen that the active component particles are uniformly distributed on the carrier, and the particle size of the nano clusters formed by the active components on the carrier surface is in the range of 3 to 5 nm.

[0129] Application Example 1

[0130] This application example uses a fixed-bed pilot-scale evaluation apparatus from Topchuan Scientific Equipment Co., Ltd., loaded with 50 mL of catalyst, to conduct a selective hydrogenation reaction of the post-etherification C4 feedstock. The composition of the post-etherification C4 feedstock is shown in Table 3.

[0131] Hydrogenation reaction conditions: pressure = 2.5 MPa, hydrogen flow rate = 0.3 L / h, temperature = 75℃, feed rate = 30 mL / h;

[0132] Catalysts A, B, C, D, E, F, G, H, I, and J were evaluated under the same conditions, and the results of selective hydrogenation and isomerization are shown in Table 4.

[0133] Table 3 Composition of raw materials

[0134] Isobutane n-Butane transbutene n-Butene Isobutylene maleic butene butadiene 46.015 15.089 9.947 19.918 3.324 5.306 0.1

[0135] Table 4 Evaluation results of hydroisomerization

[0136]

[0137] Application Example 2

[0138] In this embodiment, a fixed-bed pilot-scale evaluation device from Topcon Research Equipment Co., Ltd. was used, with 50 mL of catalyst loaded, to conduct a long-term stability experiment on the selective hydrogenation of the post-etherification C4 feedstock. The composition of the post-etherification C4 feedstock is shown in Table 3.

[0139] Hydrogenation reaction conditions: pressure = 2.5 MPa, hydrogen flow rate = 0.3 L / h, temperature = 75℃, feed rate = 30 mL / h;

[0140] The results of the long-cycle stability test are shown in Table 5.

[0141] Table 5. Results of Long-Period Stability Experiment

[0142] Time, h Isobutane n-Butane transbutene n-Butene Isobutylene maleic butene butadiene 0 46.015 15.089 9.947 19.918 3.324 5.306 0.1 100 46.596 16.445 18.897 5.826 3.21 8.998 0 200 46.291 16.487 18.988 5.968 3.242 8.989 0 300 44.862 17.094 19.532 5.53 3.205 9.531 0 400 45.252 17.751 19.44 4.498 3.232 9.789 0 500 48.297 16.515 18.781 5.573 3.202 9.388 0 600 48.4 16.869 19.561 5.971 3.185 8.864 0 700 47.151 16.571 18.672 5.902 3.212 9.825 0 800 45.016 17.272 19.864 4.786 3.189 9.65 0

[0143] As can be seen from the table above, the catalyst provided by this invention has the characteristics of high hydrogenation activity, high selectivity, strong isomerization ability, and good stability.

[0144] 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 catalyst for selective hydrogenation and isomerization of monoolefins, 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 molybdenum and the optional auxiliary active component Ni.

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 group may be the same or different, and each R group is independently selected from alkyl, cycloalkyl, aryl, aralkyl and alkylaryl groups. At least one R group is selected from alkyl groups of C6 or above, preferably from C6 to C20 alkyl groups. The remaining R groups 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 di(octadecyl)dimethyl quaternary ammonium salt, hexadecyltrimethyl quaternary ammonium salt, and C12-C18 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 used 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 metal composite oxide is an Al2O3-TiO2 composite oxide; preferably, based on the Al2O3-TiO2 composite oxide, the content of Ti in the Al2O3-TiO2 composite oxide, calculated as TiO2, is 5-30 wt%, more preferably 8 wt%-25 wt%; the content of Al in the Al2O3 composite oxide, calculated as Al, is 70 wt%-95 wt%, more preferably 75 wt%-92 wt%; and / or The support is a SiO2-TiO2-Al2O3 composite oxide. Preferably, based on the support, the content of Ti (calculated as TiO2) in the support is 5wt% to 25wt%, the content of Al (calculated as Al2O3) is 65wt% to 90wt%, preferably 80wt% to 90wt%, and the content of Si (calculated as SiO2) is 0.5wt% to 15wt%; and / or Based on 100 parts by mass of catalyst, the catalyst contains 5-25 parts of the main active component Mo (calculated as MoO), 0-5 parts of the co-active component Ni (calculated as its oxide), preferably 0.1-5 parts, and 70-95 parts of the support; 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 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 0.2–0.8 mL / g, preferably 0.3–0.5 mL / g. 2 / g; and / or In the catalyst, the main active component and the co-active component each exist independently in the form of their elemental form or oxide.

4. The catalyst according to any one of claims 1-3, 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 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 solvent of the organic cationic quaternary ammonium salt solution includes at least one selected from water, methanol, ethanol, benzene, toluene, isopropanol, acetone, sulfuric acid, hydrochloric acid, nitric acid, sodium hydroxide, and potassium hydroxide. Preferably, the silane reagent solution is an aqueous solution of the silane reagent with a concentration of 0.1–10 wt%, more preferably 1–10 wt%.

5. The catalyst according to any one of claims 1-4, characterized in that, The conditions for the first impregnation include: an impregnation temperature of 10°C to 50°C, an impregnation time of 1 hour to 12 hours, preferably 1 hour to 8 hours; and / or The conditions for the first and second drying processes may be the same or different, and each independently includes: a drying temperature of 60°C to 150°C, preferably 60°C to 110°C, and a drying time of 4 hours to 12 hours; 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 catalyst for selective hydrogenation and isomerization of monoolefins according to any one of claims 1-5, characterized in that, The process includes the following steps: second impregnation of the support with a molybdenum salt solution and an optional nickel salt solution, followed by third drying and second calcination of the impregnated support to obtain the catalyst.

7. The preparation method according to claim 6, characterized in that, The molybdenum salt includes at least one selected from molybdenum sulfate, nitrate, soluble carboxylate, hypophosphite, and halide, preferably at least one selected from molybdenum sulfate, molybdenum nitrate, molybdenum chloride, and molybdenum 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 molybdenum salt solution and the nickel salt solution are each independently at least one of water, methanol, ethanol, benzene, toluene, and chloroethane; and / or The concentration of the molybdenum salt solution is 0.1–0.6 mol / L; and / or The concentration of the nickel salt solution is 0.05–0.3 mol / L.

8. The preparation method according to claim 6 or 7, 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.

9. The application of the catalyst for selective hydrogenation and isomerization of mono-olefins according to any one of claims 1-5, or the catalyst for selective hydrogenation and isomerization of mono-olefins prepared by the method according to 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 40℃~120℃, the pressure is 0.5MPa~3.0MPa, the volume ratio of hydrogen flow rate to fresh feed is 10~300:1, and the feed volume hourly space velocity is 0.1~2.0h. -1 .

10. A method for selectively hydrogenating alkynes from a C4 fraction to remove alkynes and increase butadiene production, wherein the C4 fraction and hydrogen are selectively hydrogenated in the presence of a catalyst for selective hydrogenation and isomerization of mono-olefins as described in any one of claims 1-5 or a catalyst for selective hydrogenation and isomerization of mono-olefins prepared by the method described in claims 6-8, preferably, the conditions for the selective hydrogenation reaction include: The reaction temperature is 40℃~120℃, the pressure is 0.5MPa~3.0MPa, the volume ratio of hydrogen flow rate to fresh feed is 10~300:1, and the feed volume hourly space velocity is 0.1~2.0h. -1 .

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