阅读说明：本技术 一种多孔镍基芳构化催化剂及其制备方法与应用 (Porous nickel-based aromatization catalyst and preparation method and application thereof ) 是由 朱刚利 曾德红 夏春谷 于 2021-09-02 设计创作，主要内容包括：本发明公开了一种多孔镍基芳构化催化剂及其制备方法与应用。所述制备方法包括：使包含铝盐、有机配体和第一溶剂的第一混合反应体系于150℃-220℃晶化6h-30h,制得含铝金属有机骨架；使所述含铝金属有机骨架进行第一热处理,制得金属有机骨架化合物衍生的氧化铝；使包含镍盐、所述金属有机骨架化合物衍生的氧化铝和第二溶剂的第二混合反应体系于室温反应6h-24h,制得催化剂前驱体；以及,使所述催化剂前驱体进行第二热处理,制得基于金属有机骨架化合物的多孔镍基芳构化催化剂。本发明制备的多孔镍基芳构化催化剂可用于烃类的选择性芳构化,并且表现出较高的催化活性和稳定性。(The invention discloses a porous nickel-based aromatization catalyst and a preparation method and application thereof. The preparation method comprises the following steps: crystallizing a first mixed reaction system containing aluminum salt, an organic ligand and a first solvent at 150-220 ℃ for 6-30 h to prepare an aluminum-containing metal organic framework; subjecting the aluminum-containing metal organic framework to a first heat treatment to obtain alumina derived from a metal organic framework compound; reacting a second mixed reaction system containing nickel salt, alumina derived from the metal organic framework compound and a second solvent at room temperature for 6-24 h to prepare a catalyst precursor; and carrying out second heat treatment on the catalyst precursor to obtain the porous nickel-based aromatization catalyst based on the metal organic framework compound. The porous nickel-based aromatization catalyst prepared by the invention can be used for the selective aromatization of hydrocarbons and shows higher catalytic activity and stability.)

1. A preparation method of a porous nickel-based aromatization catalyst is characterized by comprising the following steps:

crystallizing a first mixed reaction system containing aluminum salt, an organic ligand and a first solvent at 150-220 ℃ for 6-30 h to prepare an aluminum-containing metal organic framework;

carrying out first heat treatment on the aluminum-containing metal organic framework at 450-650 ℃ for 1-12 h to prepare aluminum oxide derived from the metal organic framework compound;

reacting a second mixed reaction system containing nickel salt, alumina derived from the metal organic framework compound and a second solvent at room temperature for 6-24 h to prepare a catalyst precursor;

and carrying out second heat treatment on the catalyst precursor at the temperature of 450-650 ℃ for 1-12 h to prepare the porous nickel-based aromatization catalyst based on the metal-organic framework compound.

2. The method according to claim 1, comprising: mixing an aluminum salt, an organic ligand and a first solvent to form the first mixed reaction system;

and/or, the preparation method further comprises the following steps: after the crystallization is completed, the obtained mixture is subjected to cooling separation treatment.

3. The method of claim 1, wherein: the aluminum salt comprises any one or the combination of more than two of aluminum sulfate, aluminum nitrate and aluminum chloride;

and/or the organic ligand comprises any one or the combination of more than two of terephthalic acid, isophthalic acid, trimesic acid and 4, 4-biphenyl dicarboxylic acid;

and/or the first solvent comprises any one or the combination of more than two of water, methanol, ethanol and N, N-dimethylformamide;

and/or the molar ratio of the aluminum salt to the first solvent is 0.0002-0.001: 1.

4. The method according to claim 1, comprising: in the air atmosphere, the temperature of the aluminum-containing metal organic framework is increased to 450-650 ℃ by adopting the temperature increasing rate of 2-10 ℃/min, and the first heat treatment is carried out.

5. The method according to claim 1, comprising: dissolving nickel salt in a second solvent to form a nickel salt solution, and adding alumina derived from the metal organic framework compound to form the second mixed reaction system;

and/or the nickel salt comprises any one or the combination of more than two of nickel sulfate, nickel nitrate, nickel chloride and nickel acetylacetonate; and/or, the second solvent comprises water.

6. The method according to claim 1, comprising: and in the air atmosphere, heating the catalyst precursor to 450-650 ℃ at a heating rate of 2-10 ℃/min to perform second heat treatment.

7. The method of claim 1, further comprising: carrying out pre-reduction activation treatment on the porous nickel-based aromatization catalyst based on the metal-organic framework compound;

preferably, the pre-reduction activation treatment comprises: and carrying out reduction activation treatment on the porous nickel-based aromatization catalyst based on the metal-organic framework compound at the temperature of 400-600 ℃ in a reducing atmosphere for 0.1-12 h.

8. A porous nickel-based aromatization catalyst produced by the process of any of claims 1-7.

9. The porous nickel-based aromatization catalyst of claim 8 wherein: the loading amount of nickel in the porous nickel-based aromatization catalyst is 1-10.0 wt% by mass.

10. Use of the porous nickel-based aromatization catalyst of claim 8 or 9 in a selective aromatization reaction of hydrocarbons; preferably, the use comprises the use of the porous nickel-based aromatization catalyst for the selective conversion of isobutene to produce para-xylene.

Technical Field

The invention belongs to the technical field of heterogeneous catalysis, and particularly relates to a porous nickel-based aromatization catalyst, a preparation method and an application thereof, in particular to a porous nickel-based aromatization catalyst based on a metal organic framework compound, a preparation method thereof and an application of the porous nickel-based aromatization catalyst in selective aromatization of hydrocarbons.

Background

Para-xylene, an important organic chemical raw material, is usually oxidized into terephthalic acid and then condensed with ethylene glycol to produce polyethylene terephthalate (PET), i.e., polyester, which is widely used in many aspects such as electronic devices, packaging bags, plastics, synthetic fibers, and the like. Besides, p-xylene can be used as a solvent for producing medicines, perfumes, etc.

Currently, the source of p-xylene is catalytic reforming of naphtha, C of oil refining₆₊Alkylation and disproportionation of reformate, benzene or toluene, and isomerization of C8 aromatics. With the reliance on organic chemicals, the traditional paraxylene production route has failed to meet the growing market demand. The domestic yield of the paraxylene is always in a state of short supply and demand, and new raw materials are urgently required to be explored for producing the paraxylene. With the increasing availability of shale gas and associated gas, low carbon hydrocarbon aromatization has attracted a great deal of attention from researchers. A large amount of C4 hydrocarbons are rich in catalytic cracking byproducts, and half of them are burned as fuel, which results in a serious waste of resources. Therefore, there is significant theoretical and practical significance in converting low value C4 hydrocarbons to high value aromatic products.

Aromatization of C4 hydrocarbons was first used with Pt/Al₂O₃The catalyst can generate a large amount of methane and ethane byproducts in the aromatization process of C4 hydrocarbon because Pt has stronger hydrogenation and dehydrogenation capability, and the catalyst can be used for preparing catalyst for improving the catalytic activity of C4 hydrocarbonThe selectivity to aromatics, especially para-xylene, is low. With the development of molecular sieve catalysts, metal oxides loaded on molecular sieves as carriers have been widely used for aromatization of C4 hydrocarbons, but the reaction temperature is very high (500 ℃ -600 ℃), the obtained products are aromatic hydrocarbon mixtures including benzene, toluene, xylene, ethylbenzene and the like, and the selectivity of p-xylene is low. High reaction temperatures can have several serious consequences such as severe cracking reactions, easy coking, low target selectivity, easy catalyst sintering, etc. Therefore, the development of a catalyst which is efficient at lower temperature and can directly obtain paraxylene from C4 hydrocarbon with high selectivity has important value.

Disclosure of Invention

The invention mainly aims to provide a porous nickel-based aromatization catalyst and a preparation method and application thereof, so as to overcome the defects of the prior art.

In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:

the embodiment of the invention provides a preparation method of a porous nickel-based aromatization catalyst, which comprises the following steps:

crystallizing a first mixed reaction system containing aluminum salt, an organic ligand and a first solvent at 150-220 ℃ for 6-30 h to prepare an aluminum-containing metal organic framework;

carrying out first heat treatment on the aluminum-containing metal organic framework at 450-650 ℃ for 1-12 h to prepare aluminum oxide derived from the metal organic framework compound;

reacting a second mixed reaction system containing nickel salt, alumina derived from the metal organic framework compound and a second solvent at room temperature for 6-24 h to prepare a catalyst precursor;

and carrying out second heat treatment on the catalyst precursor at the temperature of 450-650 ℃ for 1-12 h to prepare the porous nickel-based aromatization catalyst based on the metal-organic framework compound.

In some more specific embodiments, the preparation method specifically comprises: mixing an aluminum salt, an organic ligand and a first solvent to form the first mixed reaction system;

further, the preparation method further comprises the following steps: after the crystallization is completed, the obtained mixture is subjected to cooling separation treatment.

In some more specific embodiments, the aluminum salt includes any one or a combination of two or more of aluminum sulfate, aluminum nitrate, and aluminum chloride, and is not limited thereto.

Further, the organic ligand includes any one or a combination of two or more of terephthalic acid, isophthalic acid, trimesic acid, and 4, 4-biphenyldicarboxylic acid, and is not limited thereto.

Further, the first solvent includes any one or a combination of two or more of water, methanol, ethanol, and N, N-dimethylformamide, and is not limited thereto.

Further, the molar ratio of the aluminum salt to the first solvent is 0.0002-0.001: 1.

In some more specific embodiments, the preparation method specifically comprises: in the air atmosphere, the temperature of the aluminum-containing metal organic framework is increased to 450-650 ℃ by adopting the temperature increasing rate of 2-10 ℃/min, and the first heat treatment is carried out.

In some more specific embodiments, the preparation method specifically comprises: and dissolving nickel salt in a second solvent to form a nickel salt solution, and adding alumina derived from the metal organic framework compound to form the second mixed reaction system.

Further, the nickel salt includes any one or a combination of two or more of nickel sulfate, nickel nitrate, nickel chloride, and nickel acetylacetonate, and is not limited thereto.

Further, the second solvent includes water, and is not limited thereto.

In some more specific embodiments, the preparation method specifically comprises: and in the air atmosphere, heating the catalyst precursor to 450-650 ℃ at a heating rate of 2-10 ℃/min to perform second heat treatment.

In some more specific embodiments, the preparation method specifically further comprises: and carrying out pre-reduction activation treatment on the porous nickel-based aromatization catalyst based on the metal-organic framework compound.

Further, the pre-reduction activation treatment comprises: and carrying out reduction activation treatment on the porous nickel-based aromatization catalyst based on the metal-organic framework compound for 0.1-12 h in a reducing atmosphere at the temperature of 400-600 ℃.

Further, the reducing atmosphere includes a reducing atmosphere containing hydrogen, and is not limited thereto.

In some more specific embodiments, the method of preparing the porous nickel-based aromatization catalyst comprises:

the method comprises the following steps: dispersing aluminum salt and organic ligand in a molar ratio of 0.5-1.5: 1 in a solvent to form a mixed solution; wherein the molar ratio of the aluminum salt to the solvent is 0.0002-0.001: 1, the aluminum salt comprises one or a combination of more of aluminum sulfate, aluminum nitrate and aluminum chloride, and the ligand comprises one or a combination of more of terephthalic acid, isophthalic acid, trimesic acid and 4, 4-biphenyldicarboxylic acid;

step two: stirring uniformly at room temperature, transferring to a reaction kettle, crystallizing at 150-220 ℃ for 6-30 h, cooling, and carrying out solid-liquid separation to obtain MOF (Al);

step three: in the air or oxygen atmosphere, heating MOF (Al) to 400-600 ℃ at the speed of 2-10 ℃/min, and keeping the temperature for 1-12 h to obtain the aluminum oxide derived from the metal organic framework compound.

Step four: dissolving nickel salt in deionized water, adding alumina derived from the metal organic framework compound, stirring at room temperature for 6-24 h, and performing solid-liquid separation to obtain a catalyst precursor (also referred to as the catalyst precursor), which is denoted as Ni-MOF (Al); the nickel salt is nickel nitrate, nickel acetate, nickel acetylacetonate, nickel sulfate, and nickel chloride.

Step five: in the air atmosphere, heating Ni-MOF (Al) to 450-650 ℃ at the speed of 2-10 ℃/min, and keeping the temperature for 1-12 h to obtain the porous nickel-based aromatization catalyst based on the metal organic framework compound, namely MOF-Al-Ni.

And fifthly, the porous nickel-based aromatization catalyst MOF-Al-Ni based on the metal organic framework compound can also be pre-activated and reduced for 0.1 to 12 hours at the temperature of 400-600 ℃ in a reducing atmosphere, and is marked as MOF-Al-Ni-Ac.

In the above preparation method, preferably, the ligand used comprises one or a combination of several of terephthalic acid, isophthalic acid, trimesic acid and 4, 4-biphenyldicarboxylic acid.

In the above preparation method, preferably, the solvent used includes one or a combination of several of deionized water, methanol, ethanol, and N, N-dimethylformamide.

In the above preparation method, preferably, in the second step, the crystallization temperature is 180 ℃ and the crystallization time is 24 hours.

In the above preparation method, preferably, in the third step, the temperature rise rate is 5 ℃/min, the baking temperature is 550 ℃, and the baking time is 4 h.

In the above preparation method, preferably, in the fourth step, the nickel salt is nickel nitrate hexahydrate.

In the above preparation method, preferably, in the fourth step, the stirring time is 16 hours.

In the above preparation method, preferably, in the third step, the temperature rise rate is 5 ℃/min, the baking temperature is 550 ℃, and the baking time is 4 h.

The embodiment of the invention also provides the porous nickel-based aromatization catalyst prepared by the method.

Furthermore, the loading amount of nickel metal in the porous nickel-based aromatization catalyst is 1-10.0 wt% by mass fraction.

Further, the mesoporous size of the porous nickel-based aromatization catalyst is 3-20 nm, the micropore size is 0.3-0.8 nm, and the specific surface area is 120-350 m²/g。

The embodiment of the invention also provides the application of the porous nickel-based aromatization catalyst in the selective aromatization reaction of hydrocarbons.

For example, the use includes the use of the porous nickel-based aromatization catalyst for the selective conversion of isobutylene to produce para-xylene at low temperatures.

Compared with the prior art, the invention has the beneficial effects that:

(1) the preparation method of the porous nickel-based aromatization catalyst comprises the steps of taking aluminum salt as a metal source, coordinating with a ligand, roasting to obtain alumina derived from a metal organic framework compound as a carrier, and loading the metal organic framework compound of a nickel species by adopting a post-impregnation method;

(2) according to the preparation method of the porous nickel-based aromatization catalyst, oxides derived from MOF materials are used as carriers, and a post-impregnation method is adopted to load active metal components, so that interaction with proper strength exists between active metals and the carriers, and high dispersion and stability of the active metals are realized;

(3) the porous nickel-based aromatization catalyst prepared by the invention can be used for selective aromatization of hydrocarbons, isobutene can be selectively converted into p-xylene at low temperature, the catalyst shows higher catalytic activity, the yield of the p-xylene reaches 21%, the selectivity of the p-xylene in the aromatic hydrocarbons can reach more than 95%, a certain amount of carbon octaalkane products are also generated, and isooctane in the carbon octaalkane accounts for more than 97%; meanwhile, the catalyst has high stability, can have better activity at 350 ℃, and can resist the reaction temperature of 500 ℃; the reaction temperature is used for 20 times in a circulating way without obvious reduction of the activity.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a TEM image of a porous nickel-based aromatization catalyst based on a metal-organic framework compound in example 2 of the present invention;

FIG. 2a is an X-ray diffraction pattern (XRD) of the metal organic framework compound MOF (Al) of example 2 of the present invention;

FIG. 2b is an X-ray diffraction pattern (XRD) of the porous nickel-based aromatization catalyst based on metal-organic framework compounds according to example 2 of the present invention;

FIG. 3a is Al2p X-ray photoelectron spectrum (XPS) of porous nickel-based aromatization catalyst based on metal-organic framework compounds according to example 2 of the present invention;

FIG. 3b is Ni2p X-ray photoelectron spectroscopy (XPS) of the porous nickel-based aromatization catalyst based on metal-organic framework compounds according to example 2 of the present invention;

FIG. 3c is an S2p X-ray photoelectron spectrum (XPS) of the porous nickel-based aromatization catalyst based on metal-organic framework compounds according to example 2 of the present invention;

FIG. 3d is an O1s X-ray photoelectron spectroscopy (XPS) spectrum of the porous nickel-based aromatization catalyst based on metal-organic framework compounds according to example 2 of the present invention;

FIG. 4a is a graph showing the time-dependent change of the conversion rate of the porous nickel-based aromatization catalyst based on a metal-organic framework compound to catalyze the aromatization of isobutene in example 5 of the present invention.

FIG. 4b is a graph showing the relationship between the yield of p-xylene over time in the case of the aromatization of isobutylene catalyzed by the porous nickel-based aromatization catalyst based on a metal-organic framework compound in example 5 of the present invention.

Detailed Description

In view of the defects of the prior art, the inventor of the present invention has made extensive research and practice to propose the technical solution of the present invention,

the technical solutions of the present invention will be described clearly and completely below, and it should be apparent that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The experimental materials used in the examples used below were all available from conventional biochemical reagents companies, unless otherwise specified.

Example 1

In order to achieve the above technical object, the present invention provides a preparation method of a porous nickel-based aromatization catalyst based on a metal-organic framework compound, comprising the steps of:

dispersing organic ligands of one or a combination of more of aluminum sulfate, aluminum nitrate or aluminum chloride and one or a combination of more of terephthalic acid, isophthalic acid, trimesic acid or 4, 4-biphenyldicarboxylic acid in a molar ratio of 0.5: 1, or 1: 1, or 1.5: 1, or within a certain range in a solvent to form a mixed solution; wherein the molar ratio of the aluminum salt to the solvent is 0.0002: 1, or 0.0005: 1, or 0.001: 1, or a ratio within the interval; the solvent comprises one or more of deionized water, methanol, ethanol and N, N-dimethylformamide. Stirring the mixed solution evenly at room temperature, transferring the mixed solution into a reaction kettle, a crystallization kettle, a hydrothermal kettle or a heatable container capable of realizing similar functions, crystallizing at 150 deg.C, 160 deg.C, 170 deg.C, 180 deg.C, 190 deg.C, 200 deg.C, 210 deg.C, 220 deg.C or within certain interval for 30 hr, 25 hr, 20 hr, 15 hr, 10 hr, 8 hr, 6 hr or within certain interval, cooling, centrifuging, filtering, precipitating, etc., drying the mixture in a drying oven at a temperature of 50 ℃, or 60 ℃, or 70 ℃, or 80 ℃, or 90 ℃, or 100 ℃, or 110 ℃, or 120 ℃, or 150 ℃ or within a certain interval for 30 hours, or 25 hours, or 20 hours, or 15 hours, or 10 hours, or 8 hours, or 6 hours, or within a certain time interval, and drying to obtain the MOF (Al). Then, in an air atmosphere or an oxygen atmosphere, heating the MOF (Al) to 400 ℃, 450 ℃, 500 ℃, 550 ℃, 600 ℃, or a certain temperature in the interval at a speed of 2 ℃/min, or 5 ℃/min, or 7.5 ℃/min, or 10 ℃/min, or a certain speed in the interval, and keeping the temperature for 12 hours, or 8 hours, or 4 hours, or 2 hours, or 1 hour, or a certain time in the interval, so as to obtain the aluminum oxide derived from the metal organic framework compound. And then dissolving nickel nitrate, nickel acetate, nickel acetylacetonate, nickel sulfate, nickel chloride or a mixture in deionized water, adding the alumina derived from the metal organic framework compound, stirring for 6-24 h at room temperature, and performing solid-liquid separation to obtain a catalyst precursor, which is recorded as Ni-MOF (Al). Then, in a static or flowing air or oxygen atmosphere, raising the temperature of Ni-MOF (Al) to 450 ℃, or 500 ℃, or 550 ℃, or 600 ℃, or 650 ℃, or a certain temperature in the interval at a rate of 2 ℃/min, or 5 ℃/min, or 7.5 ℃/min, or 10 ℃/min, or a certain rate in the interval, keeping the temperature for 12 hours, or 8 hours, or 4 hours, or 2 hours, or 1 hour, or a certain time period in the interval, and obtaining the porous nickel-based aromatization catalyst based on the metal organic framework compound, namely MOF-Al-Ni. The porous nickel-based aromatization catalyst MOF-Al-Ni based on the metal organic framework compound can also be preactivated, and is marked as MOF-Al-Ni-Ac after being kept at a constant temperature for 12 hours, 6 hours, 3 hours, 1 hour, 0.1 hour or a certain time in an interval at 400 ℃, 450 ℃, 500 ℃, 550 ℃, 600 ℃ or a certain temperature in the interval in a reducing atmosphere.

During the activity evaluation of the aromatization of isobutene (which will also be used in the other examples):

the conversion of isobutene is defined as:

the yield of p-xylene is defined as:

example 2

The embodiment provides a preparation method of a porous nickel-based aromatization catalyst MOF-Al-Ni based on a metal organic framework compound, which comprises the following steps:

preparation of a porous nickel-based aromatization catalyst based on a metal-organic framework compound:

firstly, dispersing an aluminum source and an organic ligand in a solvent to form a mixed solution, transferring the mixed solution to a reaction kettle for crystallization, roasting to obtain an oxide carrier, loading nickel species by adopting a post-impregnation method, and roasting to obtain the porous nickel-based aromatization catalyst based on a metal organic framework compound. The method comprises the following specific steps:

dispersing 4mmol of aluminum sulfate octadecahydrate and 4mmol of terephthalic acid in 50mL of deionized water to form a mixed solution; stirring uniformly at room temperature, transferring to a 100mL reaction kettle, crystallizing at 180 ℃ for 24h, cooling, and carrying out solid-liquid separation to obtain MOF (Al); in a static air atmosphere, heating MOF (Al) to 550 ℃ at the speed of 5 ℃/min, and keeping the temperature for 4h to obtain aluminum oxide derived from the metal organic framework compound; dissolving 0.6mmol of nickel nitrate hexahydrate in 10mL of deionized water, adding the aluminum oxide derived from the metal organic framework compound, stirring for 16h at room temperature, and carrying out solid-liquid separation to obtain a catalyst precursor Ni-MOF (Al); in a static air atmosphere, heating Ni-MOF (Al) to 550 ℃ at the rate of 5 ℃/min and keeping the temperature for 4h to obtain the porous nickel-based aromatization catalyst MOF-Al-Ni based on metal organic framework compounds.

The metal organic framework compound mof (al) obtained in example 2 and the porous nickel-based aromatization catalyst based on the metal organic framework compound are characterized by TEM, XRD, XPS and other techniques.

The transmission electron microscope image of the porous nickel-based aromatization catalyst based on the metal-organic framework compound is shown in fig. 1, and the transmission electron microscope image of the porous nickel-based aromatization catalyst based on the metal-organic framework compound is shown in fig. 1, so that the morphology of the porous nickel-based aromatization catalyst based on the metal-organic framework compound is uniform.

The X-ray diffraction patterns (XRD) of the metal organic framework compound MOF (al) and the porous nickel-based aromatization catalyst based on the metal organic framework compound are shown in fig. 2a and fig. 2b, from fig. 2a, MOF (al) shows characteristic diffraction peaks of a typical metal organic framework, from fig. 2b, the MOF material is loaded with nickel species after being calcined, the characteristic diffraction peaks of MOF disappear, several sharp peaks appear, and the characteristic peaks attributed to nickel oxide show that the metal organic framework is decomposed and the nickel species is loaded.

The X-ray photoelectron spectra of Al2p, Ni2p, S2p and O1S of the porous nickel-based aromatization catalyst based on the metal-organic framework compound are respectively shown in FIG. 3a, FIG. 3b, FIG. 3c and FIG. 3d, and it can be seen from FIG. 3a that only one Al with the binding energy of 74.0eV is present in the porous nickel-based aromatization catalyst based on the metal-organic framework compound³⁺A species; as can be seen from FIG. 3b, inOnly one nickel species with the binding energy of 855.9eV exists in the porous nickel-based aromatization catalyst based on the metal-organic framework compound; as can be seen from fig. 3c, only one sulfur atom with a binding energy of 168.9eV is present in the porous nickel-based aromatization catalyst based on metal-organic framework compounds; as can be seen from fig. 3d, there are two types of oxygen atoms in the porous nickel-based aromatization catalyst based on metal-organic framework compounds, lattice oxygen species (530.5eV) and surface oxygen species (531.6eV), respectively.

Example 3

This example provides a method for preparing a porous nickel-based aromatization catalyst based on metal-organic framework compounds comprising the steps of:

dispersing 4mmol of aluminum sulfate octadecahydrate and 4mmol of terephthalic acid in 50mL of deionized water to form a mixed solution; stirring uniformly at room temperature, transferring to a 100mL reaction kettle, crystallizing at 210 ℃ for 24h, cooling, and carrying out solid-liquid separation to obtain MOF (Al); in a static air atmosphere, heating MOF (Al) to 500 ℃ at the speed of 5 ℃/min and keeping the temperature for 4h to obtain aluminum oxide derived from the metal organic framework compound; dissolving 0.3mmol of nickel nitrate hexahydrate in 10mL of deionized water, adding the aluminum oxide derived from the metal organic framework compound, stirring for 16h at room temperature, and carrying out solid-liquid separation to obtain a catalyst precursor Ni-MOF (Al); in an air atmosphere, heating Ni-MOF (Al) to 500 ℃ at the speed of 5 ℃/min and keeping the temperature for 4h to obtain the porous nickel-based aromatization catalyst MOF-Al-Ni based on metal organic framework compounds.

Example 4

The embodiment provides a preparation method of a porous nickel-based aromatization catalyst based on a metal-organic framework compound, which comprises the following steps:

dispersing 6mmol of aluminum sulfate octadecahydrate and 4mmol of terephthalic acid in 50mL of deionized water to form a mixed solution; stirring uniformly at room temperature, transferring to a 100mL reaction kettle, crystallizing at 210 ℃ for 6h, cooling, and carrying out solid-liquid separation to obtain MOF (Al); in a static air atmosphere, heating MOF (Al) to 600 ℃ at the speed of 5 ℃/min and keeping the temperature for 4h to obtain aluminum oxide derived from the metal organic framework compound; dissolving 0.2mmol of nickel nitrate hexahydrate in 10mL of deionized water, adding the aluminum oxide derived from the metal organic framework compound, stirring for 8h at room temperature, and carrying out solid-liquid separation to obtain a catalyst precursor Ni-MOF (Al); in a static air atmosphere, raising the temperature of Ni-MOF (Al) to 600 ℃ at the speed of 5 ℃/min and keeping the temperature for 4h to obtain the porous nickel-based aromatization catalyst MOF-Al-Ni based on metal-organic framework compounds.

Example 5

This example provides the application of the porous nickel-based aromatization catalyst based on metal-organic framework compounds prepared in example 2 in the selective conversion of isobutene into paraxylene, comprising the following steps:

weighing the porous nickel-based aromatization catalyst based on the metal organic framework compound prepared in the example 2, and loading the catalyst into an isothermal fixed bed, wherein the catalyst amount is 0.5 g; before heating, purging with inert nitrogen for 1h, heating to 500 ℃, switching to hydrogen-nitrogen mixed gas, reducing for 1.5h at the temperature, then purging with nitrogen for 1.0h, switching the gas to isobutene-nitrogen mixed gas after the temperature of a bed layer is reduced to 350 ℃ and stabilized, starting reaction after the temperature is stabilized for 10min, keeping the reaction pressure at 0.15MPa, and controlling the flow rate of the mixed gas at 7.0 mL/min. The outlet product was condensed in a cold trap and the product composition was analyzed by gas chromatography. At 350 deg.c, the isobutene conversion per pass was 50%, the yield of p-xylene was 15%, and the selectivity to p-xylene in aromatics was 90%, as shown in fig. 4 a-4 b.

Example 6

This example provides the application of the porous nickel-based aromatization catalyst based on metal-organic framework compounds prepared in example 3 in the selective conversion of isobutene into paraxylene, comprising the following steps:

weighing the porous nickel-based aromatization catalyst based on the metal organic framework compound prepared in the example 3, and loading the catalyst into an isothermal fixed bed, wherein the catalyst amount is 0.5 g; before heating, purging with inert nitrogen for 1h, heating to 500 ℃, switching to hydrogen-nitrogen mixed gas, reducing for 1.5h at the temperature, purging with nitrogen for 1.0h, changing the bed temperature to the reaction temperature and stabilizing, switching the gas to isobutene-nitrogen mixed gas, stabilizing for 10min, and starting to react, wherein the reaction pressure is kept at 0.15MPa, and the flow rate of the mixed gas is controlled at 7.0 mL/min. The outlet product was condensed in a cold trap and the product composition was analyzed by gas chromatography. The conversion per pass of isobutene is 92% at 500 ℃, the yield of p-xylene is 11%, the selectivity of p-xylene in aromatic hydrocarbon is 63%, the product also contains 6% of octaalkane, and isooctane in octaalkane is more than 97%. The conversion per pass of isobutene is 71% at 450 ℃, the yield of p-xylene is 13%, the selectivity of p-xylene in aromatic hydrocarbon is 95%, the product also contains 2% of octaalkane, and isooctane in octaalkane accounts for more than 98%. The catalyst is regenerated, calcined at 500 ℃ in air and then the catalyst test process is repeated, and the activity can still keep stable after more than 20 times of circulation.

Example 7

This example provides a method for preparing a porous nickel-based aromatization catalyst based on metal-organic framework compounds comprising the steps of:

dispersing 4mmol of aluminum nitrate and 4mmol of isophthalic acid in 200mL of deionized water to form a mixed solution; stirring uniformly at room temperature, transferring to a 500mL reaction kettle, crystallizing at 150 ℃ for 30h, cooling, and carrying out solid-liquid separation to obtain MOF (Al); in a static air atmosphere, heating MOF (Al) to 450 ℃ at the speed of 2 ℃/min and keeping the temperature for 12h to obtain aluminum oxide derived from a metal organic framework compound; dissolving 0.3mmol of nickel chloride in 10mL of deionized water, adding the aluminum oxide derived from the metal organic framework compound, stirring for 24h at room temperature, and carrying out solid-liquid separation to obtain a catalyst precursor Ni-MOF (Al); in an air atmosphere, heating Ni-MOF (Al) to 450 ℃ at the speed of 2 ℃/min and keeping the temperature for 12h to obtain the porous nickel-based aromatization catalyst MOF-Al-Ni based on metal organic framework compounds.

Example 8

This example provides a method for preparing a porous nickel-based aromatization catalyst based on metal-organic framework compounds comprising the steps of:

dispersing 4mmol of aluminum chloride and 4mmol of 4, 4-biphenyldicarboxylic acid in 100mL of deionized water to form a mixed solution; stirring uniformly at room temperature, transferring to a 200mL reaction kettle, crystallizing at 220 ℃ for 6h, cooling, and carrying out solid-liquid separation to obtain MOF (Al); in a static air atmosphere, heating MOF (Al) to 650 ℃ at the speed of 10 ℃/min and keeping the temperature for 1h to obtain aluminum oxide derived from the metal organic framework compound; dissolving 0.3mmol of nickel acetylacetonate in 10mL of deionized water, adding the aluminum oxide derived from the metal organic framework compound, stirring for 6h at room temperature, and carrying out solid-liquid separation to obtain a catalyst precursor Ni-MOF (Al); in an air atmosphere, heating Ni-MOF (Al) to 650 ℃ at a speed of 10 ℃/min and keeping the temperature for 1h to obtain the porous nickel-based aromatization catalyst MOF-Al-Ni based on metal-organic framework compounds.

Comparative example 1

With commercial alumina (active gamma-Al)₂O₃) As a carrier, Ni metal content which is the same as that of the catalyst in the embodiment 2 is loaded by an impregnation method, and Ni/gamma-Al is obtained after the same treatment procedures as those in the embodiment 2₂O₃A catalyst. When tested according to the procedure and reaction conditions of example 5, no aromatic product nor para-xylene product (< 0.1%) was obtained at 350 degrees.

Comparative example 2

As purchased alumina (10% Ni/Al)₂O₃) The catalyst was tested according to the procedure and reaction conditions of example 5 and found to yield neither aromatic nor para-xylene product (< 0.1%) at 350 degrees.

In addition, the inventors of the present invention have also made experiments with other materials, process operations, and process conditions described in the present specification with reference to the above examples, and have obtained preferable results.

It should be understood that the technical solution of the present invention is not limited to the above-mentioned specific embodiments, and all technical modifications made according to the technical solution of the present invention fall within the protection scope of the present invention without departing from the spirit of the present invention and the protection scope of the claims.