Catalyst containing beta / y composite molecular sieve, preparation method and application thereof and method for liquid phase transalkylation of aromatic hydrocarbons

Abstract

The present application relates to the field of catalysts, and discloses a catalyst containing a Beta / Y composite molecular sieve, a preparation method and application thereof, and a method for aromatic liquid phase transalkylation, wherein the catalyst contains the Beta / Y composite molecular sieve and nickel, the mass percentage of the Beta / Y composite molecular sieve is 95-99% based on the total amount of the catalyst, and the mass percentage of nickel is 1-5% based on the nickel oxide. The catalyst is beneficial to promoting the aromatic liquid phase transalkylation reaction, and has the characteristics of high aromatic conversion rate and high xylene selectivity.

Description

Technical Field

[0001] This invention relates to the field of catalysts, specifically to a catalyst containing a Beta / Y composite molecular sieve, its preparation method, its application, and a method for liquid-phase alkyl transfer of aromatics. Background Technology

[0002] Xylene, as an important organic chemical raw material, has a wide range of industrial applications. It can be used as a solvent in industries such as coatings, resins, dyes, and inks; as a synthetic monomer or solvent in industries such as pharmaceuticals, explosives, and pesticides; and as a component of high-octane gasoline. The most widely used xylene product is para-xylene, which is used to produce polyesters, and its demand is increasing daily. The main industrial methods for producing xylene include: 1) using naphtha as raw material through a series of processes such as catalytic reforming, separation, and purification to obtain xylene and other high-value-added products; 2) utilizing toluene disproportionation and alkyl transfer processes, i.e., the conversion of toluene and C9 aromatics into benzene and xylene under the action of a catalyst. This reaction mainly includes: toluene disproportionation reaction and alkyl transfer reaction. Toluene disproportionation reaction generally refers to the reaction of two toluene molecules to produce one benzene molecule and one xylene molecule. Alkyl transfer reaction generally refers to the reaction of one toluene molecule and one trimethylbenzene molecule under the action of a catalyst to produce two xylene molecules.

[0003] Conventional toluene disproportionation and alkyl transfer processes are typically carried out at high reaction temperatures (350-410℃). The materials are mixed in the gas phase and converted in contact with the catalyst. The reaction usually consumes a large amount of hydrogen. The target products, benzene and xylene, are separated from the products. The unreacted useful materials are separated and recycled. During the reaction, there is usually excessive cracking, resulting in the loss of aromatics. A small amount of heavy aromatic byproducts are also generated, which cannot be converted and need to be discharged. All of these factors increase energy consumption and production costs.

[0004] Although major international oil companies have developed new disproportionation and alkyl transfer catalysts in recent years, the energy consumption of the operating units remains high. Therefore, the development of liquid-phase aromatic alkyl transfer catalysts and their process technologies is proposed to alleviate the high energy consumption problem in xylene production by refineries. Liquid-phase aromatic alkyl transfer technology involves mixing reactants in a liquid phase and contacting them with a catalyst for conversion. The reaction temperature is typically between 200-330℃. It has advantages such as low energy consumption, low aromatic loss, few by-products, and high xylene selectivity. Although hydrogen is required in the reaction, the amount used is much lower than in gas-phase reactions; hydrogen only needs to be dissolved in the reactants.

[0005] CN109790084A discloses a method for alkyl transfer of heavy aromatic hydrocarbons. (From C9) + Methods for producing xylene from aromatics include using C9... +The first feedstock of aromatics is contacted with the catalyst under effective vapor-phase dealkylation conditions in the presence of 0 wt% or more hydrogen, to partially alkylate the C9 hydrocarbons. + Aromatic dealkylation produces compounds including benzene, toluene, and residual C9. + The first product of aromatic hydrocarbons. Contains C9. + The second feedstock of aromatics and benzene and / or toluene is reacted with the second catalyst in an effective liquid phase C9. + Contact under alkyl transfer conditions to at least partially contact the C9. + Aromatic alkyl transfer occurs, producing a second product containing xylene.

[0006] CN108779047A discloses a method for liquid-phase aromatic alkyl transfer, using catalysts including molecular sieves with a three-dimensional 12-membered ring framework structure and molecular sieves with a one-dimensional 12-membered ring framework structure, with at least [number missing] pore channels. The method comprises acidic microporous materials and / or molecular sieves having an MWW framework structure. The method includes alkyl transfer, wherein at least a portion of the feed to the alkyl transfer method is in the liquid phase; some embodiments include a liquid-phase alkyl transfer method for naphthalene-containing feed streams.

[0007] CN109803944A discloses a method for disproportionation and alkyl transfer of heavy aromatics. It includes: (a) contacting a toluene-containing feedstock with a first catalyst under effective gas-phase toluene disproportionation conditions to disproportionate the toluene and produce a first product comprising benzene, unreacted toluene, and a greater amount of p-xylene than the equilibrium amount; and (b) under effective C9... + Under alkyl transfer conditions, in the presence of 0 wt% or more hydrogen with a hydrogen / hydrocarbon molar ratio of 0-10, C9 hydrocarbons are... + The aromatic hydrocarbon and benzene feedstocks are contacted with a second catalyst to make the C9... + This method involves the transfer of aromatic alkyl groups and the production of a second product containing xylene. The improvement focuses primarily on the alkyl transfer process and does not modify the catalyst itself.

[0008] Current related technologies suffer from low aromatic conversion efficiency and low xylene selectivity under liquid-phase conditions. Therefore, a catalyst is needed for alkyl transfer reactions to improve xylene selectivity while reducing aromatic loss and byproduct formation. Summary of the Invention

[0009] The purpose of this invention is to overcome the problems of low aromatic conversion rate and low xylene selectivity in the liquid-phase aromatic alkyl transfer reaction of the prior art, and to provide a catalyst containing Beta / Y composite molecular sieve, its preparation method and application, and a method for liquid-phase aromatic alkyl transfer. This catalyst is beneficial to promoting the liquid-phase alkyl transfer reaction of aromatics and has the characteristics of high aromatic conversion rate and high xylene selectivity.

[0010] To achieve the above objectives, the first aspect of the present invention provides a catalyst containing a Beta / Y composite molecular sieve, wherein the catalyst comprises a Beta / Y composite molecular sieve and nickel, and the mass percentage of the Beta / Y composite molecular sieve is 95-99% based on the total amount of the catalyst, and the mass percentage of nickel, calculated as nickel oxide, is 1-5%.

[0011] Preferably, in the Beta / Y composite molecular sieve, the weight ratio of Beta molecular sieve to Y molecular sieve is 2-5:1, more preferably 2-4:1.

[0012] A second aspect of the present invention provides a method for preparing a catalyst containing a Beta / Y composite molecular sieve, wherein the method comprises:

[0013] (1) The Beta molecular sieve is mixed with an extrusion aid and a silicone-based binder, shaped and dried to obtain dry strips;

[0014] (2) The dried strips from step (1) are subjected to hydrothermal treatment in a solution containing an alkali source and an aluminum source to obtain a Beta / Y composite molecular sieve.

[0015] (3) The Beta / Y composite molecular sieve from step (2) was impregnated in a solution containing nickel precursor and then calcined to obtain the catalyst.

[0016] The catalyst comprises a Beta / Y composite molecular sieve and nickel. Based on the total amount of catalyst, the Beta / Y composite molecular sieve has a mass percentage content of 95-99%, and the nickel has a mass percentage content of 1-5% based on nickel oxide.

[0017] The third aspect of this invention provides a catalyst containing Beta / Y composite molecular sieve prepared by the preparation method described in the second aspect.

[0018] The fourth aspect of this invention provides the application of the catalyst containing Beta / Y composite molecular sieves described in the first or third aspect in the liquid-phase alkyl transfer reaction of aromatics.

[0019] A fifth aspect of the present invention provides a method for liquid-phase alkyl transfer of aromatic hydrocarbons, the method comprising: in the presence of hydrogen, under liquid-phase reaction conditions, reacting a mixture containing toluene and C9... + A mixture of aromatics is reacted with a catalyst selected from the catalysts containing Beta / Y composite molecular sieves described in the first or third aspect.

[0020] The beneficial effects obtained by the present invention through the above technical solution are as follows:

[0021] The catalyst containing Beta / Y composite molecular sieve provided by this invention uses Beta / Y composite molecular sieve as a support to combine the active component nickel, which is beneficial for promoting the formation of toluene and C9. + Aromatic materials undergo alkyl transfer reactions. Under liquid-phase reaction conditions, the catalytic activity is high, characterized by high aromatic conversion rate and high xylene selectivity. Attached Figure Description

[0022] Figure 1 This is the XRD pattern of the Beta / Y composite molecular sieve from Example 1. Detailed Implementation

[0023] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0024] The first aspect of the present invention provides a catalyst containing a Beta / Y composite molecular sieve, wherein the catalyst comprises a Beta / Y composite molecular sieve and nickel, and the mass percentage of the Beta / Y composite molecular sieve is 95-99% based on the total amount of the catalyst, and the mass percentage of nickel, calculated as nickel oxide, is 1-5%.

[0025] In this invention, a Beta / Y composite molecular sieve is used to combine an active component, nickel, which provides hydrogenation activity, thus promoting the addition of toluene and C9. + Aromatic materials undergo alkyl transfer reactions. Under liquid-phase reaction conditions, the catalytic activity is high, characterized by high aromatic conversion rate and high xylene selectivity.

[0026] In this invention, the mass percentage of Beta / Y composite molecular sieve in the catalyst and the mass percentage of nickel (calculated as nickel oxide) are determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The testing instrument is a Varian 725-ES series ICP-AES instrument.

[0027] According to the present invention, preferably, the Beta / Y composite molecular sieve has a mass percentage content of 97-99% based on the total amount of catalyst, and a nickel mass percentage content of 1-3% based on nickel oxide.

[0028] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on mass, unless being based on mass would not be in accordance with the common understanding of those skilled in the art.

[0029] According to the present invention, preferably, the Beta / Y composite molecular sieve has a core-shell structure, comprising a core phase of Beta molecular sieve and a shell phase of Y molecular sieve. In the present invention, a layer of Y molecular sieve is coated on the outside of the Beta molecular sieve. The Y molecular sieve formed by in-situ transformation has a certain proportion of mesoporous structure, a larger specific surface area, which facilitates the diffusion of reactant molecules, allows them to approach the acid center active site more quickly, and further improves catalytic activity.

[0030] According to the present invention, preferably, in the Beta / Y composite molecular sieve, the weight ratio of Beta molecular sieve to Y molecular sieve is 2-5:1, for example 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, or any range between the two, preferably 2-4:1. In the present invention, the Beta / Y composite molecular sieve with the above weight ratio can fully utilize the pore structure and acid center distribution characteristics of the two molecular sieves to achieve synergistic catalysis and improve the efficiency of liquid-phase alkyl transfer reactions.

[0031] In this invention, the weight ratio of Beta molecular sieve and Y molecular sieve in the Beta / Y composite molecular sieve is determined by measuring the ratio of characteristic peak areas in the XRD pattern.

[0032] According to the present invention, preferably, the average grain size of the Beta / Y composite molecular sieve is less than 500 nm, and more preferably 100-300 nm. In this invention, the particle size analysis of the Beta / Y composite molecular sieve is obtained by observation using an XL30E scanning electron microscope from Philips GmbH, Netherlands. In this invention, the Beta / Y composite molecular sieve has a small average grain size, a large specific surface area, and numerous and easily accessible active sites, resulting in a catalyst with high catalytic activity.

[0033] According to the present invention, preferably, the SiO2 / Al2O3 molar ratio of the Beta molecular sieve is 8-20, for example 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or any range between the two, preferably 10-15. In the present invention, the above-mentioned Beta molecular sieve is selected as the core phase of the composite molecular sieve. The Beta molecular sieve has a low SiO2 / Al2O3 molar ratio, many active sites, and is easy to contact with the reacting molecules, thereby improving the diffusion rate of the liquid phase reaction.

[0034] In this invention, the source of the Beta molecular sieve is not particularly limited. It can be commercially available or prepared by existing methods, as long as the SiO2 / Al2O3 molar ratio of the Beta molecular sieve meets the above-mentioned limiting range.

[0035] According to the present invention, preferably, the SiO2 / Al2O3 molar ratio of the Y molecular sieve is 4-10, for example 4, 5, 6, 7, 8, 9, 10, or any range between the two, preferably 5-8. In the present invention, the Y molecular sieve with the above-mentioned SiO2 / Al2O3 molar ratio has a higher acidity, which helps to increase the number of active sites in the molecular sieve. Under low-temperature reaction conditions in the liquid phase, the catalyst can also have high activity, high aromatic hydrocarbon conversion rate, and high xylene selectivity.

[0036] In this invention, the SiO2 / Al2O3 molar ratio of the Y molecular sieve was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), using a Varian 725-ES series ICP-AES instrument.

[0037] In this invention, by Figure 1 The XRD pattern of the Beta / Y composite molecular sieve shows the presence of characteristic diffraction peaks for both Beta and Y molecular sieves. This demonstrates that the Beta / Y composite molecular sieve contains both Beta and Y molecular sieves.

[0038] A second aspect of the present invention provides a method for preparing a catalyst containing a Beta / Y composite molecular sieve, wherein the method comprises:

[0039] (1) The Beta molecular sieve is mixed with an extrusion aid and a silicone-based binder, shaped and dried to obtain dry strips;

[0040] (2) The dried strips from step (1) are subjected to hydrothermal treatment in a solution containing an alkali source and an aluminum source to obtain a Beta / Y composite molecular sieve.

[0041] (3) The Beta / Y composite molecular sieve from step (2) was impregnated in a solution containing nickel precursor and then calcined to obtain the catalyst.

[0042] The catalyst comprises a Beta / Y composite molecular sieve and nickel. Based on the total amount of catalyst, the Beta / Y composite molecular sieve has a mass percentage content of 95-99%, and the nickel has a mass percentage content of 1-5% based on nickel oxide.

[0043] According to the present invention, preferably, the Beta / Y composite molecular sieve has a mass percentage content of 97-99% based on the total amount of catalyst, and a nickel mass percentage content of 1-3% based on nickel oxide.

[0044] According to the present invention, the types of extrusion aids are well known to those skilled in the art. Preferably, the extrusion aid is selected from at least one of guar gum powder, methylcellulose, hydroxypropyl methylcellulose, and dextrin.

[0045] According to the present invention, the amount of the extrusion aid is not particularly limited, and those skilled in the art can make adaptive adjustments as needed to ensure smooth subsequent molding. Preferably, the amount of the extrusion aid is 3-10% of the weight of the Beta molecular sieve on a dry basis, more preferably 5-8%.

[0046] In this invention, the dry basis refers to calcination at 550°C for 3 hours.

[0047] According to the present invention, preferably, the silicon-based binder is silica sol and / or water glass. Silica sol is preferred.

[0048] According to the present invention, preferably, the amount of the silicon-based binder, based on SiO2, is 24-61% of the weight of the Beta molecular sieve on a dry basis, more preferably 30-61%. In this invention, the addition of the silicon-based binder serves both as a binder for mixing and molding in step (1) and as a silicon source for the subsequent hydrothermal reaction in step (2). No additional binder is required during the molding process in step (1).

[0049] In this invention, there are no particular limitations on the way the Beta molecular sieve, extrusion aid, and silicone binder are added; they can be added separately or together.

[0050] According to a preferred embodiment of the present invention, Beta molecular sieve and extrusion aid are mixed evenly, and then a silicone-based binder is added and the mixing continues.

[0051] The present invention does not specifically limit the mixing conditions in step (1), and can select appropriate conditions according to specific circumstances, as long as the purpose of uniform mixing can be achieved. The equipment for performing the mixing is not particularly limited, but preferably, it is performed in a kneader.

[0052] The present invention does not particularly limit the molding process in step (1), and it can be carried out according to conventional molding methods in the art. For example, it can be, but is not limited to, extrusion molding, spray molding, or compression molding. Extrusion molding is preferred in the present invention, and the specific method is well known to those skilled in the art, and will not be described in detail here.

[0053] According to a specific embodiment of the present invention, the mixture obtained in step (1) is first kneaded to obtain a dough-like shape, and then extruded into a cylindrical strip.

[0054] The present invention does not particularly limit the drying conditions, which can be appropriately selected according to specific circumstances, as long as the drying purpose is achieved. Preferably, the drying conditions include: a temperature of 60-150℃ and a time of 3-12 hours.

[0055] According to the present invention, the type of alkali source is not particularly limited, and any conventional strong alkali is acceptable. Preferably, the alkali source is sodium hydroxide and / or potassium hydroxide. In the present invention, when the silicon-based binder is silica sol, an additional alkali source needs to be added. The amount of alkali source added can be adjusted by those skilled in the art according to the preparation of the composite molecular sieve, as long as the structure of the composite molecular sieve meets the requirements.

[0056] According to the present invention, the type of aluminum source is not particularly limited, and it is a conventional aluminum source used in the preparation of molecular sieves in the art. Preferably, the aluminum source is selected from at least one of sodium aluminate, aluminum sulfate, and aluminum nitrate.

[0057] In this invention, the alkali source and aluminum source undergo a hydrothermal reaction with the formed support strips to coat the surface of the Beta molecular sieve with a Y molecular sieve shell through in-situ growth. The coated Y molecular sieve shell has a mesoporous structure and a larger specific surface area, which facilitates molecular diffusion and further enhances catalytic activity.

[0058] According to the present invention, preferably, in step (2), the silicon-based binder is calculated as SiO2, the alkali source is calculated as Na2O, and the aluminum source is calculated as Al2O3, and the molar ratio of each substance added satisfies n(SiO2):n(Al2O3):n(Na2O):n(H2O)=8-15:1:2.4-6:96-240, preferably 8-12:1:2.4-4.6:96-216. After dissolving the alkali source and aluminum source according to the above molar ratio, the dry support strip is added for hydrothermal reaction, which can produce Y molecular sieve with a smaller SiO2 / Al2O3 molar ratio, increase the active sites in the molecular sieve, and produce a catalyst with high aromatic conversion rate and high xylene selectivity.

[0059] According to the present invention, preferably, the hydrothermal treatment conditions include: a reaction temperature of 90-120℃, more preferably 90-110℃; and a reaction time of 6-36h, more preferably 12-24h. In this invention, the hydrothermal reaction is carried out under the above conditions. The hydrothermal reaction can be static or dynamic, but during dynamic hydrothermal treatment, the stirring paddle must not touch the formed carrier. Reasonable control of the material ratio and hydrothermal treatment conditions can prevent the formation of other impurity phases during the crystallization process.

[0060] In this invention, there are no particular limitations on the equipment used for the hydrothermal reaction, as long as the reaction can be carried out under hydrothermal conditions. Those skilled in the art can choose the appropriate equipment as needed.

[0061] In this invention, the hydrothermal treatment is followed by cooling and filtration steps. The cooling and filtration methods are not particularly limited and are conventional methods in the art.

[0062] According to the present invention, preferably, the method further includes, in step (3), exchanging the Beta / Y composite molecular sieve with ammonia, and then performing the impregnation. In the present invention, the ammonia exchange conditions are not particularly limited; those skilled in the art can choose conventional ammonia exchange conditions to exchange the Beta / Y composite molecular sieve into the ammonia form.

[0063] In this invention, the impregnation conditions are not particularly limited, and those skilled in the art can choose conventional impregnation conditions. Preferably, this invention employs an equal-volume impregnation method.

[0064] According to the present invention, the type of nickel precursor is not particularly limited, and is a conventional soluble nickel salt in the art. Preferably, the nickel precursor is nickel nitrate and / or nickel acetate.

[0065] According to the present invention, preferably, the nickel mass concentration in the solution containing the nickel precursor is 1.5-5 wt%, more preferably 1.8-4 wt%.

[0066] In this invention, the mass ratio of the Beta / Y composite molecular sieve to the solution containing the nickel precursor is not particularly limited, so that the mass percentage of nickel in the final catalyst, calculated as nickel oxide, meets the limit. Those skilled in the art can make adaptive adjustments according to the loading of the active component nickel.

[0067] The present invention does not particularly limit the calcination conditions, and can be carried out with reference to conventional methods in the art. The calcination is generally carried out in an air atmosphere, which includes a flowing atmosphere and may also include a stationary atmosphere. According to the present invention, preferably, the calcination conditions include: a temperature of 450-650℃, preferably 500-600℃; and a time of 2-10 hours, preferably 3-8 hours.

[0068] The third aspect of this invention provides a catalyst containing Beta / Y composite molecular sieve prepared by the preparation method described in the second aspect.

[0069] The fourth aspect of this invention provides the application of the catalyst containing Beta / Y composite molecular sieves described in the first or third aspect in the liquid-phase alkyl transfer reaction of aromatics.

[0070] A fifth aspect of the present invention provides a method for liquid-phase alkyl transfer of aromatic hydrocarbons, the method comprising: in the presence of hydrogen, under liquid-phase reaction conditions, reacting a mixture containing toluene and C9... + A mixture of aromatics is reacted with a catalyst selected from the catalysts containing Beta / Y composite molecular sieves described in the first or third aspect.

[0071] According to the present invention, preferably, the liquid-phase reaction conditions include: a temperature of 200-350°C, more preferably 250-300°C; a pressure of 2-5 MPa, more preferably 3-4 MPa; and a mass hourly space velocity of 0.5-2.5 h⁻¹. -1 Preferably 1-2 hours -1 .

[0072] The "in the presence of hydrogen" described in this invention is a conventional choice in the art, and various hydrogen-containing gases can be used to implement this invention, as long as the amount of hydrogen in the hydrogen-containing gas meets the requirements of toluene and C9 in this invention. + The conditions for the liquid-phase reaction of the aromatic hydrocarbon mixture are as described. This invention does not have specific requirements for these conditions and will not be described in detail here.

[0073] In this invention, the product contains toluene and C9 + Toluene and C9 in aromatic hydrocarbon mixtures + The content range of aromatics is relatively wide, and those skilled in the art can make adaptive adjustments based on the liquid-phase reaction conditions. Preferably, the toluene content in the mixture is 30-70% by weight, and the C9... + The weight content of aromatics is 30-70%.

[0074] This invention relates to C9 + The range of aromatic hydrocarbons that can be selected is relatively wide, as long as they can be mixed with toluene and react in the liquid phase to produce xylene. The C9... + The aromatic hydrocarbon is selected from at least one of the aromatic hydrocarbons containing nine or more carbon atoms.

[0075] In this invention, the content of aromatic hydrocarbons is determined by gas chromatography. The testing instrument is an Agilent Technologies 7890A GC System.

[0076] According to a particularly preferred embodiment of the present invention, a method for preparing a catalyst containing a Beta / Y composite molecular sieve, the method comprising:

[0077] (1) The Beta molecular sieve is mixed with an extrusion aid and a silicone-based binder, shaped and dried to obtain dry strips;

[0078] (2) The dried strips from step (1) are subjected to hydrothermal treatment in a solution containing an alkali source and an aluminum source to obtain a Beta / Y composite molecular sieve.

[0079] (3) The Beta / Y composite molecular sieve from step (2) was impregnated in a solution containing nickel precursor and then calcined to obtain the catalyst.

[0080] The catalyst comprises a Beta / Y composite molecular sieve and nickel. Based on the total amount of the catalyst, the mass percentage of the Beta / Y composite molecular sieve is 97-99%, and the mass percentage of nickel, calculated as nickel oxide, is 1-3%.

[0081] In step (2), the silicon-based binder is calculated as SiO2, the alkali source is calculated as Na2O, and the aluminum source is calculated as Al2O3. The molar ratio of each substance added satisfies n(SiO2):n(Al2O3):n(Na2O):n(H2O)=8-12:1:2.4-4.6:96-216;

[0082] The hydrothermal treatment conditions include: a reaction temperature of 90-110℃ and a reaction time of 12-24h.

[0083] The present invention will now be described in detail through examples and comparative examples. In the following examples and comparative examples,

[0084] The definition of aromatic hydrocarbon conversion rate is as follows:

[0085]

[0086] The selectivity of xylene is defined as follows:

[0087]

[0088] The mass percentage of nickel in the catalyst (calculated as nickel oxide), the weight ratio of Beta molecular sieve to Y molecular sieve in the Beta / Y composite molecular sieve, the average grain size, the SiO2 / Al2O3 molar ratio of the Beta molecular sieve, and the test methods for the SiO2 / Al2O3 molar ratio of the Y molecular sieve are described in the foregoing specification and will not be repeated here.

[0089] Unless otherwise specified, all reagents and materials used are commercially available, and the room temperature is 25°C.

[0090] Example 1

[0091] 65g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 10) and 4g of guar gum powder were mixed evenly in a kneader. 99g of silica sol (containing 40wt% SiO2) was added, and the mixture was kneaded for 30-40 minutes to obtain a dough-like consistency. The dough was then extruded through a mold into cylindrical strips with a diameter of 1.7mm and a length of 2.0mm, and dried at 120℃ for 6 hours. The dried strips were placed in a solution containing 12g of sodium hydroxide (96wt% NaOH), 20.5g of sodium aluminate (41wt% Al2O3, 26wt% Na2O), and 178g of water, and hydrothermally treated at 110℃ for 16 hours. After cooling, the liquid was filtered off, and the mixture was conventionally exchanged into the ammonia form. The mixture was then dried at 120℃ for 6 hours. An equal volume of the carrier was impregnated in an aqueous solution containing 7.8g of nickel nitrate, and then dried at 120℃ and calcined in air at 550℃ for 4 hours to obtain catalyst A. See Table 1 for details.

[0092] Figure 1 This is the XRD pattern of the Beta / Y composite molecular sieve from Example 1. Figure 1 As can be seen from the data, the characteristic diffraction peaks of both Beta and Y molecular sieves are present in the Beta / Y composite molecular sieve.

[0093] Example 2

[0094] 73.5 g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 10) and 4.4 g of guar gum powder were mixed evenly in a kneader. 73.5 g of silica sol (containing 40 wt% SiO2) was added, and the mixture was kneaded for 30-40 minutes to obtain a dough-like consistency. The dough was then extruded through a mold into cylindrical strips with a diameter of 1.7 mm and a length of 2.0 mm, and dried at 120 °C for 6 hours. The dried strips were placed in a solution containing 8.9 g of sodium hydroxide (96 wt% NaOH), 15.2 g of sodium aluminate (41 wt% Al2O3, 26 wt% Na2O), and 132 g of water, and hydrothermally treated at 110 °C for 16 hours. After cooling, the liquid was filtered off, and the mixture was conventionally exchanged into the ammonia form. The mixture was then dried at 120 °C for 6 hours. An equal volume of the carrier was impregnated in an aqueous solution containing 7.8 g of nickel nitrate, and then dried at 120 °C and calcined in air at 550 °C for 4 hours to obtain catalyst B. See Table 1 for details.

[0095] Example 3

[0096] 78.4 g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 10) and 4.7 g of guar gum powder were mixed evenly in a kneader. 58.5 g of silica sol (containing 40 wt% SiO2) and 20 g of water were added, and the mixture was kneaded for 30-40 minutes to obtain a dough-like consistency. The dough was extruded through a mold into cylindrical strips with a diameter of 1.7 mm and a length of 2.0 mm, and dried at 120 °C for 6 hours. The dried strips were then placed in a solution containing 7.1 g of sodium hydroxide (96 wt% NaOH), 12.2 g of sodium aluminate (41 wt% Al2O3, 26 wt% Na2O), and 106 g of water, and hydrothermally treated at 110 °C for 16 hours. After cooling, the liquid was filtered off, and the mixture was conventionally exchanged into the ammonia form. The mixture was then dried at 120 °C for 6 hours. An equal volume of the carrier was impregnated in an aqueous solution containing 7.8 g of nickel nitrate, and then dried at 120 °C and calcined in air at 550 °C for 4 hours to obtain catalyst C. See Table 1 for details.

[0097] Example 4

[0098] 81.7 g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 10) and 5 g of guar gum powder were mixed evenly in a kneader. 49 g of silica sol (containing 40 wt% SiO2) and 30 g of water were added, and kneaded for 30-40 minutes to obtain a dough-like consistency. The dough was extruded through a mold into cylindrical strips with a diameter of 1.7 mm and a length of 2.0 mm, and dried at 120 °C for 6 h. The dried strips were placed in a solution containing 5.9 g of sodium hydroxide (96 wt% NaOH), 10.1 g of sodium aluminate (41 wt% Al2O3, 26 wt% Na2O), and 88 g of water, and hydrothermally treated at 110 °C for 16 h. After cooling, the liquid was filtered off, and the mixture was conventionally exchanged into the ammonia form. The mixture was dried at 120 °C for 6 h. An equal volume of the carrier was impregnated in an aqueous solution containing 7.8 g of nickel nitrate, and then dried at 120 °C and calcined in air at 550 °C for 4 h to obtain catalyst D. See Table 1 for details.

[0099] Example 5

[0100] 72.8 g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 10) and 4 g of guar gum powder were mixed evenly in a kneader. 72.8 g of silica sol (containing 40 wt% SiO2) was added, and the mixture was kneaded for 30-40 minutes to obtain a dough-like consistency. The dough was then extruded through a mold into cylindrical strips with a diameter of 1.7 mm and a length of 2.0 mm, and dried at 120 °C for 6 hours. The dried strips were placed in a solution containing 8.8 g of sodium hydroxide (96 wt% NaOH), 15 g of sodium aluminate (41 wt% Al2O3, 26 wt% Na2O), and 130 g of water, and hydrothermally treated at 110 °C for 16 hours. After cooling, the liquid was filtered off, and the mixture was conventionally exchanged into the ammonia form. The mixture was then dried at 120 °C for 6 hours. An equal volume of the carrier was impregnated in an aqueous solution containing 11.7 g of nickel nitrate, and then dried at 120 °C and calcined in air at 550 °C for 4 hours to obtain catalyst E, as detailed in Table 1.

[0101] Example 6

[0102] 72g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 10) and 4.3g of guar gum powder were mixed evenly in a kneader. 72g of silica sol (containing 40wt% SiO2) was added, and the mixture was kneaded for 30-40 minutes to obtain a dough-like consistency. This dough was then extruded through a mold into cylindrical strips with a diameter of 1.7mm and a length of 2.0mm, and dried at 120℃ for 6 hours. The dried strips were then placed in a solution containing 8.7g of sodium hydroxide (96wt% NaOH), 14.9g of sodium aluminate (41wt% Al2O3, 26wt% Na2O), and 130g of water, and hydrothermally treated at 110℃ for 16 hours. After cooling, the liquid was filtered off, and the mixture was conventionally exchanged into the ammonia form and dried at 120℃ for 6 hours. An equal volume of the carrier was impregnated in an aqueous solution containing 15.6g of nickel nitrate, and then dried at 120℃ and calcined in air at 550℃ for 4 hours to obtain catalyst F (see Table 1 for details).

[0103] Example 7

[0104] 73.5g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 20) and 4.4g of guar gum powder were mixed evenly in a kneader. 73.5g of silica sol (containing 40wt% SiO2) was added, and the mixture was kneaded for 30-40 minutes to obtain a dough-like consistency. The dough was then extruded through a mold into cylindrical strips with a diameter of 1.7mm and a length of 2.0mm. The strips were dried at 120℃ for 6 hours. The dried strips were then placed in a solution containing 8.9g of sodium hydroxide (96wt% NaOH), 15.2g of sodium aluminate (41wt% Al2O3, 26wt% Na2O), and 132g of water. The solution was hydrothermally treated at 110℃ for 16 hours. After cooling, the liquid was filtered off, and the mixture was conventionally exchanged into the ammonia form. The solution was dried at 120℃ for 6 hours. An equal volume of the carrier was impregnated in an aqueous solution containing 7.8g of nickel nitrate. The solution was then dried at 120℃ and calcined in air at 550℃ for 4 hours to obtain catalyst G. See Table 1 for details.

[0105] Example 8

[0106] 73.5g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 10) and 4.4g of guar gum powder were mixed evenly in a kneader. 78.7g of silica sol (containing 40wt% SiO2) was added, and the mixture was kneaded for 30-40 minutes to obtain a dough-like consistency. The dough was extruded through a mold into cylindrical strips with a diameter of 1.7mm and a length of 2.0mm. The strips were dried at 120℃ for 6 hours. The dried strips were then placed in a solution containing 10g of sodium hydroxide (96wt% NaOH), 8.7g of sodium aluminate (41wt% Al2O3, 26wt% Na2O), and 142g of water. The solution was hydrothermally treated at 110℃ for 16 hours. After cooling, the liquid was filtered off, and the mixture was conventionally exchanged into the ammonia form. The solution was dried at 120℃ for 6 hours. An equal volume of the carrier was impregnated in an aqueous solution containing 7.8g of nickel nitrate. The solution was then dried at 120℃ and calcined in air at 550℃ for 4 hours to obtain catalyst H. See Table 1 for details.

[0107] Example 9

[0108] 73.5g of dry Beta molecular sieve (SiO2 / Al2O3 molar ratio of 10) and 4.4g of guar gum powder were mixed evenly in a kneader. 73.5g of silica sol (containing 40wt% SiO2) was added, and the mixture was kneaded for 30-40 minutes to obtain a dough-like consistency. The dough was then extruded through a mold into cylindrical strips with a diameter of 1.7mm and a length of 2.0mm. The strips were dried at 120℃ for 6 hours. The dried strips were then placed in a solution containing 7g of sodium hydroxide (96wt% NaOH), 15.2g of sodium aluminate (41wt% Al2O3, 26wt% Na2O), and 132g of water. The solution was hydrothermally treated at 120℃ for 24 hours. After cooling, the liquid was filtered off, and the mixture was conventionally exchanged into the ammonia form. The solution was dried at 120℃ for 6 hours. An equal volume of the carrier was impregnated in an aqueous solution containing 7.8g of nickel nitrate. The solution was then dried at 120℃ and calcined in air at 550℃ for 4 hours to obtain catalyst I. See Table 1 for details.

[0109] Comparative Example 1

[0110] 67.5g of Beta (SiO2 / Al2O3 molar ratio of 10), 22.5g of HY molecular sieve (SiO2 / Al2O3 molar ratio of 5), 10g of alumina, and 4g of guar gum powder were mixed evenly in a kneader. 45g of an aqueous solution containing 0.5g of nitric acid was slowly added to the kneader and kneaded for 30 minutes to obtain a dough-like consistency. The dough was extruded through a mold into cylindrical strips with a diameter of 1.7mm and a length of 2.0mm. After drying at 120℃ for 6 hours, the carrier was impregnated in an aqueous solution containing 7.8g of nickel nitrate. The catalyst was then dried at 120℃ and calcined in air at 550℃ for 4 hours. See Table 1 for details.

[0111] Comparative Example 2

[0112] 73.5g of dry Beta molecular sieve (SiO2 / Al2O3 molar ratio of 10) and 4.4g of guar gum powder were mixed evenly in a kneader. 73.5g of silica sol (containing 40wt% SiO2) was added, and the mixture was kneaded for 30-40 minutes to obtain a dough-like consistency. The dough was then extruded through a mold into cylindrical strips with a diameter of 1.7mm and a length of 2.0mm. The strips were dried at 120℃ for 6 hours. The dried strips were then placed in a solution containing 8.9g of sodium hydroxide (96wt% NaOH), 15.2g of sodium aluminate (41wt% Al2O3, 26wt% Na2O), and 132g of water. The solution was hydrothermally treated at 110℃ for 16 hours. After cooling, the liquid was filtered off, and the mixture was conventionally exchanged into the ammonia form. The solution was dried at 120℃ for 6 hours. An equal volume of the carrier was impregnated in an aqueous solution containing 10.6g of magnesium nitrate. The solution was then dried at 120℃ and calcined in air at 550℃ for 4 hours to obtain the catalyst. See Table 1 for details.

[0113] Comparative Example 3

[0114] Dissolve 8.9g of sodium hydroxide (96wt% NaOH) and 15.2g of sodium aluminate (41wt% Al2O3, 26wt% Na2O) in 88g of water, then add 73.3g of silica sol. After stirring evenly, add 73.5g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 10) on a dry basis. After hydrothermal treatment at 110℃ for 16h, filter, exchange, wash, and dry. Add the mixture to a kneader and mix evenly with 5g of guar gum powder. Then add 43.2g of silica sol (containing 40wt% SiO2), add water and knead for 30-40 minutes to obtain a dough-like consistency. Extrude the dough through a mold into cylindrical strips with a diameter of 1.7mm and a length of 2.0mm. Dry at 120℃ for 6h. Impregnate an equal volume of the carrier in an aqueous solution containing 9.2g of nickel nitrate. Then dry at 120℃ and calcine in air at 550℃ for 4h to obtain the catalyst. See Table 1 for details.

[0115] Table 1

[0116]

[0117] Test case

[0118] The catalysts prepared in the examples and comparative examples were respectively loaded into fixed-bed reactors and subjected to a temperature of 275°C, a pressure of 3.5 MPa, and a space velocity of 1.5 h⁻¹. -1 The liquid-phase alkyl transfer reaction was carried out under a hydrogen atmosphere. The composition of the raw materials is shown in Table 2, and the reaction results are listed in Table 3.

[0119] Table 2

[0120] Components Toluene <![CDATA[C9 Aromatics]]> <![CDATA[C 10 Aromatic hydrocarbons Mass content, % 50 45 5

[0121] Table 3

[0122] catalyst Aromatic hydrocarbon conversion rate, % Xylene selectivity, % A 47.8 83.9 B 48.3 85.2 C 47.1 84.6 D 46.5 81.8 E 49.0 82.1 F 49.2 80.0 G 46.5 83.6 H 46.7 83.4 I 47.6 85.1 Comparative Example 1 34.3 70.1 Comparative Example 2 35.8 68.2 Comparative Example 3 30.9 72.3

[0123] The catalysts prepared in the examples and comparative examples were respectively loaded into fixed-bed reactors and subjected to temperature of 290°C, pressure of 4.0 MPa, and space velocity of 1.0 h⁻¹. -1 The liquid-phase alkyl transfer reaction was carried out under a hydrogen atmosphere. The composition of the raw materials is shown in Table 2, and the reaction results are listed in Table 4.

[0124] Table 4

[0125] catalyst Aromatic hydrocarbon conversion rate, % Xylene selectivity, % A 48.2 83.5 B 49.0 84.8 C 47.8 84.2 D 47.0 81.2 E 49.3 80.8 F 49.6 79.5 G 47.1 83.1 H 47.2 82.9 I 48.2 84.5 Comparative Example 1 35.0 69.2 Comparative Example 2 36.1 67.0 Comparative Example 3 31.2 72.0

[0126] As can be seen from the results in Tables 3 and 4, the catalyst containing Beta / Y composite molecular sieve provided by this invention, through the combination of Beta / Y composite molecular sieve with nickel active component under liquid phase reaction conditions, has higher aromatic conversion rate and higher xylene selectivity. It can be used in the industrial production of para-xylene to achieve the purpose of increasing xylene production.

[0127] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. The application of a catalyst containing a Beta / Y composite molecular sieve in the liquid-phase alkyl transfer reaction of aromatics, characterized in that, In the presence of hydrogen, under liquid-phase reaction conditions, a mixture containing toluene and C9 will be produced. + A mixture of aromatics reacts with a catalyst to produce xylene; The catalyst comprises a Beta / Y composite molecular sieve and nickel. Based on the total amount of catalyst, the Beta / Y composite molecular sieve has a mass percentage content of 95-99%, and the nickel has a mass percentage content of 1-5% (based on nickel oxide). The Beta / Y composite molecular sieve has a core-shell structure, comprising a core phase of Beta molecular sieve and a shell phase of Y molecular sieve.

2. The application according to claim 1, wherein, Based on the total amount of catalyst, the Beta / Y composite molecular sieve has a mass percentage content of 97-99%, and a nickel mass percentage content of 1-3% based on nickel oxide.

3. The application according to claim 1, wherein, In the Beta / Y composite molecular sieve, the weight ratio of Beta molecular sieve to Y molecular sieve is 2-5:1; And / or, the average grain size of the Beta / Y composite molecular sieve is less than 500 nm.

4. The application according to claim 3, wherein, In the Beta / Y composite molecular sieve, the weight ratio of Beta molecular sieve to Y molecular sieve is 2-4:1; And / or, the average grain size of the Beta / Y composite molecular sieve is 100-300 nm.

5. The application according to claim 1, wherein, The SiO2 / Al2O3 molar ratio of the Beta molecular sieve is 8-20; And / or, the SiO2 / Al2O3 molar ratio of the Y molecular sieve is 4-10.

6. The application according to claim 5, wherein, The SiO2 / Al2O3 molar ratio of the Beta molecular sieve is 10-15; And / or, the SiO2 / Al2O3 molar ratio of the Y molecular sieve is 5-8.

7. The application according to any one of claims 1-6, wherein, The preparation method of the Beta / Y composite molecular sieve includes: (1) The Beta molecular sieve is mixed with an extrusion aid and a silicone-based binder, then shaped and dried to obtain dry strips; (2) The dried strips from step (1) are subjected to hydrothermal treatment in a solution containing an alkali source and an aluminum source to obtain a Beta / Y composite molecular sieve; (3) The Beta / Y composite molecular sieve from step (2) is impregnated in a solution containing nickel precursor and then calcined to obtain the catalyst.

8. The application according to claim 7, wherein, The extrusion aid is selected from at least one of guar gum powder, methylcellulose, hydroxypropyl methylcellulose and dextrin.

9. The application according to claim 7, wherein, The amount of the extrusion aid is 3-10% of the weight of the Beta molecular sieve on a dry basis.

10. The application according to claim 9, wherein, The amount of the extrusion aid is 5-8% of the weight of the Beta molecular sieve on a dry basis.

11. The application according to claim 7, wherein, The silicon-based binder is silica sol and / or water glass.

12. The application according to claim 7, wherein, The amount of the silicon-based binder, calculated as SiO2, is 24-61% of the weight of the Beta molecular sieve on a dry basis.

13. The application according to claim 12, wherein, The amount of the silicon-based binder, calculated as SiO2, is 30-61% of the weight of the Beta molecular sieve on a dry basis.

14. The application according to claim 7, wherein, The alkali source is sodium hydroxide and / or potassium hydroxide.

15. The application according to claim 7, wherein, The aluminum source is selected from at least one of sodium aluminate, aluminum sulfate, and aluminum nitrate.

16. The application according to claim 7, wherein, In step (2), the silicon-based binder is calculated as SiO2, the alkali source is calculated as Na2O, and the aluminum source is calculated as Al2O3. The molar ratio of each substance added satisfies n(SiO2):n(Al2O3):n(Na2O):n(H2O)=8-15:1:2.4-6:96-240.

17. The application according to claim 16, wherein, In step (2), the silicon-based binder is calculated as SiO2, the alkali source is calculated as Na2O, and the aluminum source is calculated as Al2O3. The molar ratio of the amount of each substance added satisfies the following: n(SiO2):n(Al2O3):n(Na2O):n(H2O) = 8-12:1:2.4-4.6:96-216.

18. The application according to claim 7, wherein, The hydrothermal treatment conditions include: a reaction temperature of 90-120℃ and a reaction time of 6-36h.

19. The application according to claim 18, wherein, The hydrothermal treatment conditions include: a reaction temperature of 90-110℃ and a reaction time of 12-24h.

20. The application according to claim 7, wherein, The method further includes, in step (3), exchanging the Beta / Y composite molecular sieve with ammonia and then performing the impregnation.

21. The application according to claim 7, wherein, The nickel precursor is nickel nitrate and / or nickel acetate; And / or, in the solution containing the nickel precursor, the mass concentration of nickel is 1.5-5 wt%.

22. The application according to claim 21, wherein, The nickel concentration in the solution containing the nickel precursor is 1.8-4 wt%.

23. The application according to claim 7, wherein, The roasting conditions include: a temperature of 450-650℃ and a time of 2-10 hours.

24. The application according to claim 23, wherein, The roasting conditions include: a temperature of 500-600℃ and a time of 3-8 hours.

25. The application according to claim 1, wherein, The liquid-phase reaction conditions include: a temperature of 200-350℃; a pressure of 2-5 MPa; and a mass hourly space velocity of 0.5-2.5 h⁻¹. -1 .

26. The application according to claim 25, wherein, The liquid-phase reaction conditions include: temperature of 250-300℃; pressure of 3-4 MPa; and mass hourly space velocity of 1-2 h⁻¹. -1 .

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