A Mo-based catalyst, its preparation method, and its application in olefin disproportionation reaction.

Abstract

This application discloses a Mo-based catalyst, its preparation method, and its application in olefin disproportionation reactions, comprising a support and an active component supported on the surface of the support; the support is a hierarchical porous molecular sieve-alumina composite support; the specific surface area of ​​the composite support is 280–420 m². 2 / g, possessing both microporous and mesoporous structures, with pore volumes ranging from 0.2 to 0.5 cm³. 3 / g; the active component is dispersed molybdenum oxide species; in the hierarchical porous molecular sieve-alumina composite support, the content of the hierarchical porous molecular sieve is 10-90 wt%; in the Mo-based catalyst, the content of the active component is 0.1-9 wt%. The hierarchical porous molecular sieve prepared according to this method is further used for the creation of supported molybdenum-based catalysts, and the corresponding supported molybdenum-based catalysts exhibit high disproportionation performance at low temperatures in the butene / ethylene cross-disproportionation reaction.

Description

Technical Field

[0001] This application relates to a Mo-based catalyst, its preparation method, and its application in olefin disproportionation reactions, belonging to the field of catalysis technology. Background Technology

[0002] Olefin disproportionation is a reaction characterized by the breaking and rearrangement of carbon-carbon double bonds, playing a crucial role in regulating the distribution of olefin products. Currently, olefin disproportionation reactions are mostly concentrated on supported Re-based, Mo-based, and W-based catalysts. Although Re-based catalysts exhibit high olefin disproportionation performance at room temperature, they are expensive and prone to sublimation at high temperatures. Currently, the only industrially used catalyst is a silica-supported W-based catalyst, but it requires a high reaction temperature to ensure suitable disproportionation activity. Therefore, developing low-temperature, high-performance non-precious metal Mo and W-based catalysts is an effective way to improve the efficiency of olefin disproportionation reactions.

[0003] Molecular sieve-alumina composite supports significantly improve the low-temperature disproportionation activity of supported Mo and W-based catalysts. However, the narrow micropores of microporous molecular sieves lead to problems such as low utilization of active components and easy catalyst deactivation due to carbon deposition. Constructing intergranular mesopores offers a possibility to overcome these limitations. Introducing intergranular mesopores facilitates effective contact between the molecular sieve and alumina, forming more hierarchical porous molecular sieve-alumina specific interfaces. These specific interfaces can promote the dispersion of supported metallic Mo species and their entry into the micropores of the molecular sieve, thereby generating more reactive active centers, effectively improving the utilization of active components, and simultaneously enhancing catalyst stability. Summary of the Invention

[0004] This invention provides a method for preparing a hierarchical porous molecular sieve, and uses the obtained hierarchical porous molecular sieve for the preparation of a supported molybdenum-based catalyst, thereby realizing the creation of a catalyst with high disproportionation performance at low temperatures.

[0005] According to one aspect of this application, a Mo-based catalyst is provided, the Mo-based catalyst comprising a support and an active component supported on the surface of the support;

[0006] The carrier is a multi-level porous molecular sieve-alumina composite carrier;

[0007] The specific surface area of ​​the hierarchical porous molecular sieve-alumina composite carrier is 280–420 m². 2 / g;

[0008] The multi-level porous molecular sieve-alumina composite support has both microporous and mesoporous structures.

[0009] The pore volume of the hierarchical porous molecular sieve-alumina composite support is 0.2–0.5 cm³. 3 / g;

[0010] The active component is a dispersed molybdenum oxide species;

[0011] In the multi-level porous molecular sieve-alumina composite carrier, the content of the multi-level porous molecular sieve is 10-90 wt%.

[0012] In the Mo-based catalyst, the content of the active component is 0.1–9 wt%.

[0013] Furthermore, in the multi-level porous molecular sieve-alumina composite support, the content of multi-level porous molecular sieve is 50-70 wt%.

[0014] Furthermore, in the Mo-based catalyst, the content of the active component is 2-6 wt%.

[0015] According to another aspect of this application, a method for preparing the above-mentioned Mo-based catalyst is provided, comprising at least the following steps:

[0016] The multi-level porous molecular sieve-alumina composite support was impregnated in a molybdate solution and calcined to obtain the Mo-based catalyst.

[0017] The molybdate is selected from ammonium molybdate and / or ammonium paramolybdate;

[0018] In the molybdate solution, the concentration of molybdate is 0.01–0.32 mol / L; the upper limit of the molybdate concentration in the molybdate solution is 0.32 mol / L, 0.3 mol / L, 0.25 mol / L, 0.2 mol / L, 0.15 mol / L, 0.1 mol / L, and 0.05 mol / L; the lower limit is 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, and 0.3 mol / L.

[0019] Optionally, the solid-liquid ratio of the hierarchical porous molecular sieve-alumina composite support to the molybdate solution is 1g:0.5-1ml;

[0020] The temperature of the calcination I is 400–700°C;

[0021] The roasting time for the first roasting step is 1 to 5 hours.

[0022] Optionally, the upper limit of the roasting temperature I can be independently selected from 700℃, 650℃, 600℃, and 550℃; the lower limit can be independently selected from 400℃, 450℃, 500℃, and 550℃.

[0023] Optionally, the upper limit of the calcination time I can be independently selected from 5h, 4h, and 3h; the lower limit can be independently selected from 1h, 2h, and 3h.

[0024] The hierarchical pore molecular sieve-alumina composite support is prepared by the following steps:

[0025] The microporous molecular sieve is ball-milled and calcined II to obtain a hierarchical pore molecular sieve;

[0026] The porous molecular sieve and alumina are mixed, extruded into shape, and calcined III to obtain the hierarchical pore molecular sieve-alumina composite support.

[0027] The silica-alumina ratio of the microporous molecular sieve is 5 to 50;

[0028] The topological structure of the microporous molecular sieve is MFI, BEA or MOR;

[0029] The ball-milling time is 1 to 30 h;

[0030] Optionally, the ball-milling time is 15 to 20 h;

[0031] The ball-milling speed is 100 to 500 rpm;

[0032] Optionally, the ball-milling speed is 200 to 300 rpm;

[0033] The temperature of calcination II is 400 to 700 °C;

[0034] The time of calcination II is 1 to 5 h.

[0035] Optionally, the upper limit of the temperature of calcination I can be independently selected from 700 °C, 650 °C, 600 °C, 550 °C; the lower limit can be independently selected from 400 °C, 450 °C, 500 °C, 550 °C; <00…​​​​​​​​​​​​​​​​​

[0042] The mass ratio of the multi-level porous molecular sieve to the alumina is 5 to 0.5; the upper limit of the mass ratio of the multi-level porous molecular sieve to the alumina is 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1; the lower limit is 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5.

[0043] The temperature of calcination III is 400–700°C;

[0044] The roasting time for the third stage is 1 to 5 hours.

[0045] Optionally, the upper limit of the roasting temperature III can be independently selected from 700℃, 650℃, 600℃, and 550℃; the lower limit can be independently selected from 400℃, 450℃, 500℃, and 550℃.

[0046] Optionally, the upper limit of the roasting time III can be independently selected from 5h, 4h, and 3h; the lower limit can be independently selected from 1h, 2h, and 3h.

[0047] As one specific embodiment, the preparation method of the hierarchical porous molecular sieve and the corresponding supported catalyst includes at least the following steps:

[0048] S1: Place the parent molecular sieve and deionized water in a ball mill jar containing zirconia microspheres, then place the ball mill jar in a ball mill and run it at 100–500 rpm for 1–30 hours. Dry the ball-milled molecular sieve in an oven at 100–120℃ for 12–24 hours, then place the dried sample in a muffle furnace and calcine it at 400–700℃ for 1–5 hours to obtain a hierarchical porous molecular sieve.

[0049] S2: Grind the multi-level porous molecular sieve obtained in S1 thoroughly, add a certain amount of alumina powder and mix evenly, with the molecular sieve content being 10wt% to 90wt%; then add 1 to 5wt% guar gum powder to the mixture and mix evenly; then add a certain amount of aqueous solution containing 5 to 25wt% nitric acid, stir, knead, and extrude into strips; air dry at room temperature for 12 to 24 hours; then calcine in a muffle furnace at 400 to 700℃ for 1 to 5 hours to obtain the multi-level porous molecular sieve-alumina composite carrier.

[0050] S3: Prepare an ammonium molybdate solution of a certain concentration and impregnate it onto a multi-level porous molecular sieve-alumina composite support. Let it stand at room temperature for 12–24 hours, then dry it at 60°C for 12–24 hours. Place deionized water in a ball mill jar containing zirconia microspheres, then place the ball mill jar in a ball mill and run it at 100–500 rpm for 1–30 hours. Dry the ball-milled molecular sieve in an oven at 100–120°C for 12–24 hours, then place the dried sample in a muffle furnace and calcine it at 400–700°C for 1–5 hours.

[0051] According to another aspect of the present application, there is provided a method for producing propylene by the cross-metathesis reaction of butene / ethylene, characterized in that,

[0052] It at least includes the following steps:

[0053] Contacting a raw material gas containing 2-butene, 1-butene and ethylene with a metathesis catalyst, reacting, to obtain a product containing propylene;

[0054] Among them, the metathesis catalyst is selected from the above-mentioned Mo-based catalyst or the Mo-based catalyst prepared by the above-mentioned preparation method.

[0055] In the raw material gas, the molar content of 2-butene is 5-45%, the molar content of 1-butene is 5-45%, and the molar content of ethylene is 40-60%;

[0056] The temperature of the reaction is 80-200 °C;

[0057] Optionally, the temperature of the reaction is 90-120 °C;

[0058] The pressure of the reaction is 0.1-3.0 Mpa;

[0059] Optionally, the pressure of the reaction is 0.1-0.3 Mpa;

[0060] The mass space velocity of the raw material gas is 0.5-10 g g -1 h -1 ;

[0061] Optionally, the mass space velocity of the raw material gas is 1-3 g g -1 h -1 .

[0062] Optionally, the upper limit of the reaction temperature can be independently selected from 90 °C, 110 °C, 115 °C, 120 °C, 130 °C, 140 °C, 160 °C, 180 °C, 200 °C; the lower limit can be independently selected from 80 °C, 90 °C, 110 °C, 115 °C, 120 °C, 130 °C, 140 °C, 160 °C, 180 °C;

[0063] Optionally, the upper limit of the reaction pressure can be independently selected from 3.0 Mpa, 2.5 Mpa, 2.0 Mpa, 1.5 Mpa, 1.0 Mpa; the lower limit can be independently selected from 0.1 Mpa, 0.2 Mpa, 0.3 Mpa, 0.5 Mpa, 1.0 Mpa;

[0064] Optionally, the upper limit of the mass space velocity of the raw material gas can be independently selected from 1 g g -1 h -1 、1.2 g g -1 h -1 、1.3 g g-1 h -1 1.5gg -1 h -1 1.6gg -1 h -1 1.8gg -1 h -1 2g g -1 h -1 3g g -1 h -1 5g g -1 h -1 8g g -1 h -1 10g g -1 h -1 The lower limit can be independently selected from 0.5 gg. -1 h -1 1g g -1 h -1 1.2gg -1 h -1 1.3gg -1 h -1 1.5gg -1 h -1 1.6gg -1 h -1 1.8gg -1 h -1 2g g -1 h -1 3g g -1 h -1 5g g -1 h -1 8gg -1 h-1;

[0065] Furthermore, the method includes the following steps:

[0066] (1) A mixture of gas containing 1-butene and ethylene is contacted with an isomerization catalyst in a reactor to produce a feed gas containing 2-butene, 1-butene and ethylene.

[0067] (2) The raw gas obtained in step (1) is contacted with the disproportionation catalyst contained in the reactor to prepare propylene through disproportionation reaction;

[0068] The reaction is carried out in a continuous flow fixed bed.

[0069] The isomerization catalyst is located in the upper section of the reactor;

[0070] The disproportionation catalyst is located in the lower section of the reactor;

[0071] In the mixed gas, the molar content of 1-butene is 60-40%, and the molar content of ethylene is 40-60%

[0072] The isomerization catalyst is selected from MFI zeolite with a topological structure

[0073] The beneficial effects that can be produced by this application include:

[0074] 1) The preparation method of the hierarchical pore molecular sieve provided by this application is simple and has the potential for large-scale production.

[0075] 2) The preparation method of the supported Mo-based catalyst provided by this application is simple and has high disproportionation reaction performance. Description of the Drawings

[0076] Figure 1 is the nitrogen adsorption spectra of microporous molecular sieve HZSM-5 (Si / Al = 31) and hierarchical pore molecular sieves a and b; (a) adsorption-desorption isotherm; (b) BJH pore size distribution curve;

[0077] Figure 2 is the change curve of ethylene conversion rate with reaction time on catalyst B;

[0078] Figure 3 is the change curve of propylene selectivity with reaction time on catalyst B;

[0079] Figure 4 is the electron microscope image of catalyst B. Detailed Embodiments

[0080] The following describes this application in detail with reference to the embodiments, but this application is not limited to these embodiments.

[0081] Unless otherwise specified, the raw materials in the embodiments of this application are all purchased through commercial channels. Among them, HZSM-5 molecular sieve is purchased from Shanghai Fuxu Molecular Sieve Co., Ltd. and Nankai Catalyst Factory; Hβ molecular sieve and mordenite molecular sieve are both purchased from Nankai Catalyst Factory.

[0082] In the following application examples, the ethylene conversion rate and propylene selectivity are calculated according to the following calculation formulas:

[0083]

[0084]

[0085] Where and respectively represent the number of moles of olefins with carbon number m in the reactants and products.

[0086] Example 1 Catalyst A [[ID=1) Place 20g of HZSM-5 molecular sieve (Si / Al = 31), 40g of deionized water, and 100g of zirconia balls in a ball mill jar and treat at 200rpm for 10h. Dry the treated sample in an oven at 120℃ for 12h, and then calcine it in a muffle furnace at 550℃ for 3h to obtain hierarchical porous molecular sieve a.

[0088] 2) After mixing the multi-level porous molecular sieve, alumina and guar gum powder prepared in step (1) evenly, add 20 ml of 10 wt% nitric acid aqueous solution and knead into a cake shape, then place it in a self-made mold to extrude into strips; after drying the obtained strips at room temperature overnight, place them in a muffle furnace at 500℃ for 2 h to obtain a multi-level porous molecular sieve-alumina composite carrier, wherein the mass contents of multi-level porous molecular sieve and alumina are 80 wt% and 20 wt% respectively, and the content of guar gum powder is 3 wt% of the composite carrier.

[0089] 3) An aqueous solution containing 0.2298 g of ammonium molybdate tetrahydrate was impregnated onto 4 g of the above-mentioned hierarchical porous molecular sieve-alumina composite support, allowed to stand at room temperature for 12 h, dried overnight at 60 °C in an oven, and then calcined at 550 °C for 3 h in a muffle furnace to obtain catalyst A.

[0090] Application Example 1

[0091] 1 g of catalyst A obtained in Example 1 was placed in the middle of the reaction tube, and 2.8 g of ZSM-5 molecular sieve (Si / Al = 13.5) isomerization catalyst was placed on top of catalyst A. The two were separated by inert silica wool, and the remaining space of the reaction tube was filled with inert silica sand. The tube was then pretreated at 550°C for 1 h under a high-purity N2 atmosphere to remove adsorbed water vapor and other volatile impurities. Finally, the temperature of the reaction tube was lowered to the reaction temperature, and a mixture of 1-butene and ethylene was introduced to initiate chromatographic injection. The reaction conditions were: reaction pressure P = 0.1 MPa, reaction temperature T = 120°C, and mass hourly space velocity (HHSV) 1.8 g / kg. -1 h -1 The molar ratio of 1-butene to ethylene was 1. The evaluation results are shown in Table 1.

[0092] Table 1

[0093] Ethylene conversion rate / % Propylene selectivity / % 25.0 93.0

[0094] Example 2 Catalyst B

[0095] 1) Place 20g of HZSM-5 molecular sieve (Si / Al=31), 40g of deionized water and 100g of zirconia balls in a ball mill jar and treat at 200rpm for 20h. Dry the treated sample in an oven at 120℃ for 12h, and then calcine it in a muffle furnace at 550℃ for 3h to obtain multi-level porous molecular sieve b.

[0096] 2) After mixing the multi-level porous molecular sieve, alumina and guar gum powder prepared in step (1) evenly, add 21 ml of 10 wt% nitric acid aqueous solution and knead into a cake shape, then place it in a self-made mold to extrude into strips; after drying the obtained strips at room temperature overnight, place them in a muffle furnace at 500℃ for 2 hours to obtain a multi-level porous molecular sieve-alumina composite carrier, wherein the mass contents of multi-level porous molecular sieve and alumina are 70 wt% and 30 wt% respectively, and the content of guar gum powder is 3 wt% of the composite carrier.

[0097] 3) An aqueous solution containing 0.2298 g of ammonium molybdate tetrahydrate was impregnated onto 4 g of the above-mentioned hierarchical porous molecular sieve-alumina composite support, left to stand at room temperature for 12 h, dried overnight at 60 °C in an oven, and then calcined at 550 °C for 3 h in a muffle furnace to obtain catalyst B.

[0098] Application Example 2

[0099] 1g of catalyst B obtained in Example 2 was placed in the middle of the reaction tube, and 2.8g of isomerization catalyst was placed on top of catalyst B. The two were separated by inert silica wool, and the remaining space of the reaction tube was filled with inert silica sand. The tube was then pretreated at 550°C for 1 hour under a high-purity N2 atmosphere to remove adsorbed water vapor and other volatile impurities. Finally, the temperature of the reaction tube was lowered to the reaction temperature, and a mixture of 1-butene and ethylene was introduced to initiate chromatographic injection. The reaction conditions were: reaction pressure P = 0.1 MPa, reaction temperature T = 110°C, and mass hourly space velocity (HHSV) 1.5 g / kg. -1 h-1, the molar ratio of 1-butene to ethylene is 1. The evaluation results are shown in Table 2.

[0100] Table 2

[0101] Ethylene conversion rate / % Propylene selectivity / % 38.6 95.5

[0102] Example 3 Catalyst C

[0103] 1) Place 20g of HZSM-5 molecular sieve (Si / Al=31), 40g of deionized water and 100g of zirconia balls in a ball mill jar and treat at 200rpm for 30h. Dry the treated sample in an oven at 120℃ for 12h, and then calcine it in a muffle furnace at 550℃ for 3h to obtain a multi-level porous molecular sieve c.

[0104] 2) After mixing the multi-level porous molecular sieve, alumina and guar gum powder prepared in step (1) evenly, add 23 ml of 10 wt% nitric acid aqueous solution and knead into a cake shape, then place it in a self-made mold to extrude into strips; after drying the obtained strips at room temperature overnight, place them in a muffle furnace at 500℃ for 2 hours to obtain a multi-level porous molecular sieve-alumina composite carrier, wherein the mass contents of multi-level porous molecular sieve and alumina are 80 wt% and 20 wt% respectively, and the content of guar gum powder is 3 wt% of the composite carrier.

[0105] 3) An aqueous solution containing 0.2298 g of ammonium molybdate tetrahydrate was impregnated onto 4 g of the above-mentioned hierarchical porous molecular sieve-alumina composite support, allowed to stand at room temperature for 12 h, dried overnight at 60 °C in an oven, and then calcined at 550 °C for 3 h in a muffle furnace to obtain catalyst C.

[0106] Application Example 3

[0107] 1 g of catalyst C obtained in Example 3 was placed in the middle section of the reaction tube, and 2.8 g of isomerization catalyst was placed on top of catalyst C. The two were separated by inert silica wool, and the remaining space of the reaction tube was filled with inert silica sand. The tube was then pretreated at 550°C for 1 h under a high-purity N2 atmosphere to remove adsorbed water vapor and other volatile impurities. Finally, the temperature of the reaction tube was lowered to the reaction temperature, and a mixture of 1-butene and ethylene was introduced to initiate chromatographic injection. The reaction conditions were: reaction pressure P = 0.1 MPa, reaction temperature T = 130°C, and mass hourly space velocity (HHSV) 2.0 g / kg. -1 h -1 The molar ratio of 1-butene to ethylene was 1.2. The evaluation results are shown in Table 3.

[0108] Table 3

[0109] Ethylene conversion rate / % Propylene selectivity / % 48.6 95.9

[0110] Example 4 Catalyst D

[0111] 1) Place 20g of HZSM-5 molecular sieve (Si / Al=31), 40g of deionized water and 100g of zirconia balls in a ball mill jar and treat at 200rpm for 20h. Dry the treated sample in an oven at 120℃ for 12h, and then calcine it in a muffle furnace at 550℃ for 3h to obtain multi-level porous molecular sieve b.

[0112] 2) After mixing the multi-level porous molecular sieve, alumina and guar gum powder prepared in step (1) evenly, add 24 ml of 10 wt% nitric acid aqueous solution and knead into a cake shape, then place it in a self-made mold to extrude into strips; after drying the obtained strips at room temperature overnight, place them in a muffle furnace at 500℃ for 2 hours to obtain a multi-level porous molecular sieve-alumina composite carrier, wherein the mass contents of multi-level porous molecular sieve and alumina are 90 wt% and 10 wt% respectively, and the content of guar gum powder is 3 wt% of the composite carrier.

[0113] 3) An aqueous solution containing 0.2298 g of ammonium molybdate tetrahydrate was impregnated onto 4 g of the above-mentioned hierarchical porous molecular sieve-alumina composite support, left to stand at room temperature for 12 h, dried overnight at 60 °C in an oven, and then calcined at 550 °C for 3 h in a muffle furnace to obtain catalyst D.

[0114] Application Example 4

[0115] One g of catalyst D obtained in Example 4 was placed in the middle of the reaction tube, and 2.8 g of isomerization catalyst was placed on top of catalyst D. The two were separated by inert silica wool, and the remaining space of the reaction tube was filled with inert silica sand. The tube was then pretreated at 550°C for 1 hour under a high-purity N2 atmosphere to remove adsorbed water vapor and other volatile impurities. Finally, the temperature of the reaction tube was lowered to the reaction temperature, and a mixture of 1-butene and ethylene was introduced to initiate chromatographic injection. The reaction conditions were: reaction pressure P = 0.1 MPa, reaction temperature T = 130°C, and mass hourly space velocity (HHSV) 1.6 g / kg. -1 h -1 The molar ratio of 1-butene to ethylene was 1.5. The evaluation results are shown in Table 4.

[0116] Table 4

[0117] Ethylene conversion rate / % Propylene selectivity / % 26.9 93.8

[0118] Example 5 Catalyst E

[0119] 1) Place 20g of HZSM-5 molecular sieve (Si / Al=31), 40g of deionized water and 100g of zirconia balls in a ball mill jar and treat at 200rpm for 20h. Dry the treated sample in an oven at 120℃ for 12h, and then calcine it in a muffle furnace at 550℃ for 3h to obtain multi-level porous molecular sieve b.

[0120] 2) After mixing the multi-level porous molecular sieve, alumina and guar gum powder prepared in step (1) evenly, add 20 ml of 10 wt% nitric acid aqueous solution and knead into a cake shape, then place it in a self-made mold to extrude into strips; after drying the obtained strips at room temperature overnight, place them in a muffle furnace at 500℃ for 2 h to obtain a multi-level porous molecular sieve-alumina composite carrier, wherein the mass contents of multi-level porous molecular sieve and alumina are 50 wt% and 50 wt% respectively, and the content of guar gum powder is 3 wt% of the composite carrier.

[0121] 3) An aqueous solution containing 0.2298 g of ammonium molybdate tetrahydrate was impregnated onto 4 g of the above-mentioned hierarchical porous molecular sieve-alumina composite support, left to stand at room temperature for 12 h, dried overnight at 60 °C in an oven, and then calcined at 550 °C for 3 h in a muffle furnace to obtain catalyst E.

[0122] Application Example 5

[0123] 1 g of catalyst E obtained in Example 5 was placed in the middle section of the reaction tube, and 2.8 g of isomerization catalyst was placed on top of catalyst E. The two were separated by inert silica wool, and the remaining space of the reaction tube was filled with inert silica sand. The tube was then pretreated at 550°C for 1 h under a high-purity N2 atmosphere to remove adsorbed water vapor and other volatile impurities. Finally, the temperature of the reaction tube was lowered to the reaction temperature, and a mixture of 1-butene and ethylene was introduced to initiate chromatographic injection. The reaction conditions were: reaction pressure P = 0.1 MPa, reaction temperature T = 150°C, and mass hourly space velocity (HHSV) 2.0 g / kg. -1 h -1 The molar ratio of 1-butene to ethylene was 1. The evaluation results are shown in Table 5.

[0124] Table 5

[0125] Ethylene conversion rate / % Propylene selectivity / % 33.3 95.5

[0126] Example 6 Catalyst F

[0127] 1) Place 20g of HZSM-5 molecular sieve (Si / Al=31), 40g of deionized water and 100g of zirconia balls in a ball mill jar and treat at 200rpm for 20h. Dry the treated sample in an oven at 120℃ for 12h, and then calcine it in a muffle furnace at 550℃ for 3h to obtain multi-level porous molecular sieve b.

[0128] 2) After mixing the multi-level porous molecular sieve, alumina and guar gum powder prepared in step (1) evenly, add 18 ml of 10 wt% nitric acid aqueous solution and knead into a cake shape, then place it in a self-made mold to extrude into strips; after drying the obtained strips at room temperature overnight, place them in a muffle furnace at 500℃ for 2 hours to obtain a multi-level porous molecular sieve-alumina composite carrier, wherein the mass contents of multi-level porous molecular sieve and alumina are 30 wt% and 70 wt% respectively, and the content of guar gum powder is 3 wt% of the composite carrier.

[0129] 3) An aqueous solution containing 0.2298 g of ammonium molybdate tetrahydrate was impregnated onto 4 g of the above-mentioned hierarchical porous molecular sieve-alumina composite support, left to stand at room temperature for 12 h, dried overnight at 60 °C in an oven, and then calcined at 550 °C for 3 h in a muffle furnace to obtain catalyst F.

[0130] Application Example 6

[0131] 1 g of catalyst F obtained in Example 6 was placed in the middle section of the reaction tube, and 2.8 g of isomerization catalyst was placed on top of catalyst F. The two were separated by inert silica wool, and the remaining space of the reaction tube was filled with inert silica sand. The tube was then pretreated at 550°C for 1 h under a high-purity N2 atmosphere to remove adsorbed water vapor and other volatile impurities. Finally, the temperature of the reaction tube was lowered to the reaction temperature, and a mixture of 1-butene and ethylene was introduced to initiate chromatographic injection. The reaction conditions were: reaction pressure P = 0.1 MPa, reaction temperature T = 110°C, and mass hourly space velocity (HHSV) 1.6 g / kg. -1 h -1 The molar ratio of 1-butene to ethylene was 0.8. The evaluation results are shown in Table 6.

[0132] Table 6

[0133] Ethylene conversion rate / % Propylene selectivity / % 12.8 90.9

[0134] Example 7 Catalyst G

[0135] 1) Place 20g of HZSM-5 molecular sieve (Si / Al = 31), 40g of deionized water, and 100g of zirconia balls in a ball mill jar and treat at 450rpm for 2h. Dry the treated sample in an oven at 120℃ for 12h, and then calcine it in a muffle furnace at 550℃ for 3h to obtain a multi-level porous molecular sieve d.

[0136] 2) After mixing the multi-level porous molecular sieve, alumina and guar gum powder prepared in step (1) evenly, add 20 ml of 10 wt% nitric acid aqueous solution and knead into a cake shape, then place it in a self-made mold to extrude into strips; after drying the obtained strips at room temperature overnight, place them in a muffle furnace at 500℃ for 2 h to obtain a multi-level porous molecular sieve-alumina composite carrier, wherein the mass content of multi-level porous molecular sieve and alumina is 30 wt% and 70 wt% respectively, and the content of guar gum powder is 3 wt% of the composite carrier.

[0137] 3) An aqueous solution containing 0.2298 g of ammonium molybdate tetrahydrate was impregnated onto 4 g of the above-mentioned hierarchical porous molecular sieve-alumina composite support, allowed to stand at room temperature for 12 h, dried overnight at 60 °C in an oven, and then calcined at 550 °C for 3 h in a muffle furnace to obtain catalyst G.

[0138] Application Example 7

[0139] 1 g of catalyst G obtained in Example 7 was placed in the middle of the reaction tube, and 2.8 g of isomerization catalyst was placed on top of catalyst G. The two were separated by inert silica wool, and the remaining space of the reaction tube was filled with inert silica sand. The tube was then pretreated at 550°C for 1 h under a high-purity N2 atmosphere to remove adsorbed water vapor and other volatile impurities. Finally, the temperature of the reaction tube was lowered to the reaction temperature, and a mixture of 1-butene and ethylene was introduced to initiate chromatographic injection. The reaction conditions were: reaction pressure P = 0.1 MPa, reaction temperature T = 110°C, and mass hourly space velocity (HHSV) 1.6 g / kg. -1 h -1 The molar ratio of 1-butene to ethylene was 0.8. The evaluation results are shown in Table 7.

[0140] Table 7

[0141] Ethylene conversion rate / % Propylene selectivity / % 13.6 91.5

[0142] Example 8 Catalyst H

[0143] 1) Place 20g of HZSM-5 molecular sieve (Si / Al = 35), 40g of deionized water, and 100g of zirconia balls in a ball mill jar and treat at 300rpm for 10h. Dry the treated sample in an oven at 120℃ for 12h, and then calcine it in a muffle furnace at 550℃ for 3h to obtain a multi-level porous molecular sieve e.

[0144] 2) After mixing the multi-level porous molecular sieve, alumina and guar gum powder prepared in step (1) evenly, add 18 ml of 10 wt% nitric acid aqueous solution and knead into a cake shape, then place it in a self-made mold to extrude into strips; after drying the obtained strips at room temperature overnight, place them in a muffle furnace at 500℃ for 2 hours to obtain a multi-level porous molecular sieve-alumina composite carrier, wherein the mass contents of multi-level porous molecular sieve and alumina are 30 wt% and 70 wt% respectively, and the content of guar gum powder is 3 wt% of the composite carrier.

[0145] 3) An aqueous solution containing 0.2298 g of ammonium molybdate tetrahydrate was impregnated onto 4 g of the above-mentioned hierarchical porous molecular sieve-alumina composite support, allowed to stand at room temperature for 12 h, dried overnight at 60 °C in an oven, and then calcined at 550 °C for 3 h in a muffle furnace to obtain catalyst H.

[0146] Application Example 8

[0147] One g of catalyst H obtained in Example 8 was placed in the middle of the reaction tube, and 2.8 g of isomerization catalyst was placed above catalyst H. The two were separated by inert silica wool, and the remaining space of the reaction tube was filled with inert silica sand. The tube was then pretreated at 550°C for 1 hour under a high-purity N2 atmosphere to remove adsorbed water vapor and other volatile impurities. Finally, the temperature of the reaction tube was lowered to the reaction temperature, and a mixture of 1-butene and ethylene was introduced to initiate chromatographic injection. The reaction conditions were: reaction pressure P = 0.1 MPa, reaction temperature T = 130°C, and mass hourly space velocity (HHSV) 1.9 g / kg. -1 h -1 The molar ratio of 1-butene to ethylene was 1. The evaluation results are shown in Table 8.

[0148] Table 8

[0149] Ethylene conversion rate / % Propylene selectivity / % 26.6 93.2

[0150] Example 9 Catalyst I

[0151] 1) Place 20g of Hβ molecular sieve (Si / Al = 35), 40g of deionized water, and 100g of zirconia balls in a ball mill jar and treat at 450rpm for 2h. Dry the treated sample in an oven at 120℃ for 12h, and then calcine it in a muffle furnace at 550℃ for 3h to obtain a multi-level porous molecular sieve f.

[0152] 2) After mixing the multi-level porous molecular sieve, alumina and guar gum powder prepared in step (1) evenly, add 18 ml of 10 wt% nitric acid aqueous solution and knead into a cake shape, then place it in a self-made mold to extrude into strips; after drying the obtained strips at room temperature overnight, place them in a muffle furnace at 500℃ for 2 hours to obtain a multi-level porous molecular sieve-alumina composite carrier, wherein the mass contents of multi-level porous molecular sieve and alumina are 30 wt% and 70 wt% respectively, and the content of guar gum powder is 3 wt% of the composite carrier.

[0153] 3) An aqueous solution containing 0.2298 g of ammonium molybdate tetrahydrate was impregnated onto 4 g of the above-mentioned hierarchical porous molecular sieve-alumina composite support, allowed to stand at room temperature for 12 h, dried overnight at 60 °C in an oven, and then calcined at 550 °C for 3 h in a muffle furnace to obtain catalyst I.

[0154] Application Example 9

[0155] 1 g of catalyst I obtained in Example 8 was placed in the middle of the reaction tube, and 2.8 g of isomerization catalyst was placed on top of catalyst I. The two were separated by inert silica wool, and the remaining space of the reaction tube was filled with inert silica sand. The tube was then pretreated at 550°C for 1 h under a high-purity N2 atmosphere to remove adsorbed water vapor and other volatile impurities. Finally, the temperature of the reaction tube was lowered to the reaction temperature, and a mixture of 1-butene and ethylene was introduced to initiate chromatographic injection. The reaction conditions were: reaction pressure P = 0.1 MPa, reaction temperature T = 100°C, and mass hourly space velocity (HHSV) 2.2 g / cm³. -1 h -1 The molar ratio of 1-butene to ethylene was 1.5. The evaluation results are shown in Table 9.

[0156] Table 9

[0157] Ethylene conversion rate / % Propylene selectivity / % 30.8 93.6

[0158] Example 10 Catalyst J

[0159] 1) Place 20g of Hβ molecular sieve (Si / Al = 35), 40g of deionized water, and 100g of zirconia balls in a ball mill jar and treat at 300rpm for 8h. Dry the treated sample in an oven at 120℃ for 12h, and then calcine it in a muffle furnace at 550℃ for 3h to obtain g of hierarchical porous molecular sieve.

[0160] 2) After mixing the multi-level porous molecular sieve, alumina and guar gum powder prepared in step (1) evenly, add 18 ml of 10 wt% nitric acid aqueous solution and knead into a cake shape, then place it in a self-made mold to extrude into strips; after drying the obtained strips at room temperature overnight, place them in a muffle furnace at 500℃ for 2 hours to obtain a multi-level porous molecular sieve-alumina composite carrier, wherein the mass contents of multi-level porous molecular sieve and alumina are 30 wt% and 70 wt% respectively, and the content of guar gum powder is 3 wt% of the composite carrier.

[0161] 3) An aqueous solution containing 0.2298 g of ammonium molybdate tetrahydrate was impregnated onto 4 g of the above-mentioned hierarchical porous molecular sieve-alumina composite support, left to stand at room temperature for 12 h, dried overnight at 60 °C in an oven, and then calcined at 550 °C for 3 h in a muffle furnace to obtain catalyst J.

[0162] Application Example 10

[0163] One g of catalyst J obtained in Example 8 was placed in the middle section of the reaction tube, and 2.8 g of isomerization catalyst was placed on top of catalyst J. The two were separated by inert silica wool, and the remaining space of the reaction tube was filled with inert silica sand. The tube was then pretreated at 550°C for 1 hour under a high-purity N2 atmosphere to remove adsorbed water vapor and other volatile impurities. Finally, the temperature of the reaction tube was lowered to the reaction temperature, and a mixture of 1-butene and ethylene was introduced to initiate chromatographic injection. The reaction conditions were: reaction pressure P = 0.1 MPa, reaction temperature T = 120°C, and mass hourly space velocity (MSV) 1.8 g / g. -1 h -1 The molar ratio of 1-butene to ethylene was 1.2. The evaluation results are shown in Table 10.

[0164] Table 10

[0165] Ethylene conversion rate / % Propylene selectivity / % 28.9 93.0

[0166] Comparative Example 1 Catalyst K

[0167] 1) Mix 20g of HZSM-5 molecular sieve (Si / Al=31), alumina and guar gum powder evenly, add 18ml of 10wt% nitric acid aqueous solution and knead into a cake shape, then place it in a self-made mold and extrude it into strips; after the obtained strips are dried at room temperature overnight, they are then calcined in a muffle furnace at 500℃ for 2h to obtain a multi-level porous molecular sieve-alumina composite carrier, wherein the mass content of multi-level porous molecular sieve and alumina is 70wt% and 30wt% respectively, and the content of guar gum powder is 3wt% of the composite carrier.

[0168] 2) An aqueous solution containing 0.2298 g of ammonium molybdate tetrahydrate was impregnated onto 4 g of the above-mentioned hierarchical porous molecular sieve-alumina composite support, left to stand at room temperature for 12 h, dried overnight at 60 °C in an oven, and then calcined at 550 °C for 3 h in a muffle furnace to obtain catalyst K.

[0169] Application Comparative Example 1

[0170] 1 g of catalyst K obtained from Comparative Example 1 was placed in the middle of the reaction tube, and 2.8 g of isomerization catalyst was placed above catalyst K. The two were separated by inert silica wool, and the remaining space of the reaction tube was filled with inert silica sand. The tube was then pretreated at 550℃ for 1 h under a high-purity N2 atmosphere to remove adsorbed water vapor and other volatile impurities. Finally, the temperature of the reaction tube was lowered to the reaction temperature, and a mixture of 1-butene and ethylene was introduced to initiate chromatographic injection. The reaction conditions were: reaction pressure P = 0.1 MPa, reaction temperature T = 110℃, and mass hourly space velocity (HHSV) 1.5 g / cm³. -1 h -1 The molar ratio of 1-butene to ethylene was 1. The evaluation results are shown in Table 11.

[0171] Table 11

[0172] Ethylene conversion rate / % Propylene selectivity / % 11.0 90.4

[0173] Therefore, it can be seen that the catalyst prepared by molecular sieves that have not undergone ball milling has very low activity after a series of steps.

[0174] Test Example 1

[0175] Figure 1 The figures show nitrogen adsorption spectra of microporous molecular sieve HZSM-5 (Si / Al=31) and hierarchical molecular sieves a and b; (a) adsorption-desorption isotherms; (b) BJH pore size distribution curves; it can be seen from the figures that the molecular sieves obtained after ball milling have obvious mesoporous distribution.

[0176] The catalyst B prepared in Example 2 was subjected to a stability test under the following conditions: reaction pressure P = 0.1 MPa, reaction temperature T = 110 °C, and space velocity 1.5 h⁻¹. -1 The experimental results are as follows Figure 2 and Figure 3 As shown in the figure, catalyst B exhibits high ethylene conversion and propylene selectivity at low temperatures, and the ethylene conversion and propylene selectivity of the catalyst did not decrease significantly after 16 hours of reaction, indicating that catalyst B prepared by this method has good stability.

[0177] Figure 4 This is an electron micrograph of catalyst B. The image shows that the ZSM-5 molecular sieve is surrounded by flocculent alumina, and no MoO3 crystals were found, indicating that Mo species are highly dispersed on the molecular sieve-alumina composite support.

[0178] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A method for preparing propylene via a butene / ethylene cross-disproportionation reaction, characterized in that, Includes the following steps: A feed gas containing 2-butene, 1-butene and ethylene is contacted with a disproportionation catalyst and reacted at 9-120℃ and 0.1-3.0MPa to obtain a product containing propylene. The disproportionation catalyst is selected from Mo-based catalysts; The Mo-based catalyst includes a support and an active component supported on the surface of the support; The carrier is a multi-level porous molecular sieve-alumina composite carrier; The hierarchical porous molecular sieve-alumina composite support is prepared through the following steps: Microporous molecular sieves are ball-milled at 200-300 rpm for 15-20 hours and calcined at 400-700℃ for 1-5 hours to obtain hierarchical porous molecular sieves; the hierarchical porous molecular sieves are mixed with alumina, extruded into strips, and calcined at 400-700℃ for 1-5 hours to obtain the hierarchical porous molecular sieve-alumina composite carrier. The specific surface area of ​​the multi-level porous molecular sieve-alumina composite carrier is 280-420 m² / g, and the pore volume is 0.2-0.5 cm³ / g. In the hierarchical porous molecular sieve-alumina composite support, the content of hierarchical porous molecular sieve is 50~70 wt%; In the Mo-based catalyst, the content of the active component is 2-6 wt%; The topology of the hierarchical porous molecular sieve is MFI, BEA or MOR type; The multi-level porous molecular sieve-alumina composite support has both microporous and mesoporous structures. The active component is a dispersed molybdenum oxide species.

2. The method according to claim 1, characterized in that, The preparation of the Mo-based catalyst includes the following steps: The multi-level porous molecular sieve-alumina composite support was impregnated in a molybdate solution and calcined at 400-700℃ for 1-5 hours to obtain the Mo-based catalyst.

3. The method according to claim 2, characterized in that, The silicon-to-aluminum ratio of the microporous molecular sieve is 5 to 50.

4. The method according to claim 2, characterized in that, The silica-to-alumina ratio of the multi-level porous molecular sieve is 5~50; The multi-level porous molecular sieve is a hydrogen-type molecular sieve; The mass ratio of the multi-level porous molecular sieve to the alumina is 5~0.

5.

5. The method according to claim 2, characterized in that, The molybdate is selected from ammonium molybdate and / or ammonium paramolybdate; In the molybdate solution, the concentration of molybdate is 0.01~0.32 mol / L; The solid-liquid ratio of the multi-level porous molecular sieve-alumina composite carrier to the molybdate solution is 1g:0.5~1ml.

6. The method according to claim 1, characterized in that, In the feed gas, the molar content of 2-butene is 5-45%, the molar content of 1-butene is 5-45%, and the molar content of ethylene is 40-60%. The reaction pressure is 0.1~0.3 MPa; The mass hourly space velocity (MSV) of the feed gas is 0.5~10 g·g⁻¹. -1 ·h -1 .

7. The method according to claim 6, characterized in that, The mass hourly space velocity of the feed gas is 1~3 g·g -1 ·h -1 .

8. The method according to claim 1, characterized in that, The reaction is carried out in a continuous flow fixed bed.

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