Solid acid alkylation catalysts, methods for their preparation and use

Abstract

The present application relates to the field of molecular sieve catalysts, and discloses a solid acid alkylation catalyst and a preparation method and application thereof.The solid acid alkylation catalyst, wherein the catalyst comprises a molecular sieve and an aluminum-based binder, and the content of Al2O3 in the catalyst is 10% to 40% based on the total amount of the catalyst, w(Al2O3) represents the mass fraction of Al2O3 in the catalyst measured by an XRF method, and the Al2O3 includes Al2O3 in the aluminum-based binder and Al2O3 in the molecular sieve; and the d value of the catalyst is less than or equal to 10 nm, the d value represents the thickness of the aluminum-based binder outward along the grain edge of the molecular sieve grain measured by a TEM method.The catalyst has a high active component content and excellent binder dispersity.

Description

Technical Field

[0001] This invention relates to the technical field of molecular sieve catalysts, specifically to a solid acid alkylation catalyst, its preparation method, and its application. Background Technology

[0002] Molecular sieve catalysts possess advantages such as regular crystal structure, uniform microporous structure, large specific surface area, numerous acidic sites, good hydrothermal stability, and easy regeneration, making them widely used in the petrochemical and fine chemical synthesis industries. However, different types of reactions have different requirements for the acidic structure of molecular sieve catalysts, thus placing higher demands on them. Recent studies have found that adding binders and other additives can improve the acidic structure of molecular sieves to some extent.

[0003] Chinese patent application CN105688977A discloses a method for preparing a catalytic cracking catalyst containing boehmite. By modifying boehmite with silicon and controlling the mixing and stirring time of the silicon-containing solution and boehmite, the colloidal properties of the catalyst are modified, thereby increasing its macropore volume (greater than 100 nm) while controlling the catalyst's wear index.

[0004] Chinese patent application CN106268724A discloses a catalyst containing molecular sieves and alumina. The catalyst support contains alumina and two types of Y-type molecular sieves. Based on the support, the total content of the Y-type molecular sieves is 5%-70% by weight, and the content of alumina is 30%-95% by weight. The catalyst support is characterized by being obtained by mixing, molding, drying, and calcining the Y-type molecular sieves with boehmite. The boehmite includes PB1, characterized by X-ray diffraction. The κ1 and κ2 of PB1 are greater than 1 and less than or equal to 3, where κ1 = h2 / h1 and κ2 = h3 / h2. h1, h2, and h3 are the peak heights of three diffraction peaks at 2θ angles of 24-30°, 35-41°, and 46-52°, respectively, in the X-ray diffraction pattern of PB1. The selectivity, activity, and stability of the catalyst support are controlled by modifying the properties of the boehmite.

[0005] In traditional molecular sieve preparation methods, active components, clay or binders, and additives are generally mixed and then molded to obtain a shaped carrier. To maintain the strength and size requirements of the molecular sieve, the content of the active components in the mixture is required to be low (generally below 70%). In order to achieve good bonding effect, the added binder must be mixed evenly. Furthermore, mesoporous structures are introduced into the catalyst, which changes the microporous structure of the catalytic material and thus affects its catalytic properties. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems in the molecular sieve catalyst forming process in the prior art, and to provide a solid acid alkylation catalyst, its preparation method and application, which has a high content of active components and excellent binder dispersibility.

[0007] To achieve the above objectives, a first aspect of the present invention provides a solid acid alkylation catalyst, wherein the catalyst comprises a molecular sieve and an aluminum-based binder, and based on the total amount of catalyst, 10% ≤ w(Al2O3) ≤ 40% of the catalyst, where w(Al2O3) represents the mass fraction of Al2O3 in the catalyst as measured by XRF, and the Al2O3 comprises alumina in the aluminum-based binder and alumina in the molecular sieve; the d-value of the catalyst is ≤ 10 nm, where the d-value represents the thickness of the aluminum-based binder in the catalyst extending outward from the crystal plane edge of the molecular sieve grains as measured by TEM.

[0008] Preferably, the catalyst has a d value of 0.01-5 nm, and more preferably 0.01-1 nm.

[0009] Preferably, the aluminum-based binder contains at least a portion of free alumina, and more preferably, the catalyst does not contain free alumina with a particle size exceeding 0.1 nm.

[0010] A second aspect of the present invention provides a method for preparing a solid acid alkylation catalyst, wherein the method includes the following steps:

[0011] (1) The solid-liquid mixture containing the binder precursor solution and the molecular sieve is subjected to a hydrolysis reaction with water, and then solid-liquid separation is performed to obtain a solid mixture;

[0012] (2) The solid mixture described in step (1) is mixed with a peptide solvent, an additive and water, molded, dried and calcined to obtain a solid acid alkylation catalyst;

[0013] The binder precursor is selected from at least one of organic aluminum alkoxides.

[0014] A third aspect of the present invention provides a solid acid alkylation catalyst prepared by the preparation method described in the second aspect.

[0015] The fourth aspect of the present invention provides the application of the solid acid alkylation catalyst described in the first or third aspect in an alkylation reaction.

[0016] The catalyst provided by this invention can be formed using less binder, which ensures that the cell constant of the molecular sieve in the catalyst does not decrease as much as possible. Moreover, the binder has high dispersibility. In preferred cases, the catalyst has a high micropore ratio and a high acid content, which can keep the framework aluminum from being lost and ensure the strength of the catalyst.

[0017] The method provided by this invention involves mixing an organic aluminum alcohol binder precursor solution with a molecular sieve, followed by hydrolysis and molding to obtain a catalyst. The use of an organic aluminum alcohol binder precursor solution mixed with a molecular sieve improves the degree of binder dispersion, ensuring the dispersibility of the binder in the catalyst. Furthermore, by first mixing the organic aluminum alcohol binder precursor solution with the molecular sieve and then adding water for hydrolysis, the binder precursor is highly dispersed during the mixing process. The subsequent hydrolysis reaction generates a high-quality porous aqueous pseudoboehmite, enabling the catalyst to maintain a good microporous structure and acidity during the subsequent molding process. Attached Figure Description

[0018] Figure 1 This is the TEM-EDX energy dispersive spectroscopy (EDX) spectrum of the catalyst in Example 1. Figure 1 Image A in the image is a TEM image of the catalyst. Figure 1 B in the diagram represents the distribution of aluminum. Figure 1 C in the diagram represents the distribution of silicon. Figure 1 (D in the diagram represents the overlapping distribution of silicon and aluminum elements);

[0019] Figure 2 The TEM-EDX energy dispersive spectroscopy analysis of the catalyst in Comparative Example 1 is shown below. Figure 2 Image A in the image is a TEM image of the catalyst. Figure 2 B in the diagram represents the distribution of aluminum. Figure 2 C in the diagram represents the distribution of silicon. Figure 2 (D in the diagram represents the overlapping distribution of silicon and aluminum elements);

[0020] Figure 3 MAS NMR of the catalysts in Example 1 and Comparative Example 1 27 Al spectrum. Detailed Implementation

[0021] 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.

[0022] The first aspect of this invention provides a solid acid alkylation catalyst, wherein the catalyst comprises a molecular sieve and an aluminum-based binder, and based on the total amount of catalyst, 10% ≤ w(Al2O3) ≤ 40% of the catalyst, where w(Al2O3) represents the mass fraction of Al2O3 in the catalyst as measured by XRF, and the Al2O3 comprises alumina in the aluminum-based binder and alumina in the molecular sieve; the d-value of the catalyst is ≤ 10 nm, where the d-value represents the thickness of the aluminum-based binder in the catalyst along the edge of the crystal plane of the molecular sieve grains as measured by TEM.

[0023] In this invention, w(Al2O3) was determined by semi-quantitative elemental analysis using a Rigaku ZSX100E X-ray fluorescence spectrometer. Specific testing conditions were: tungsten target (excitation voltage 40 kV, excitation current 250 mA). The sample powder was pressed into tablets, with an applied pressure typically between 500 and 1000 kPa.

[0024] In this invention, the d-value was measured using a JEM-ARM200F aberration-corrected transmission electron microscope. The specific testing method was as follows: the sample was uniformly dispersed in ethanol, dropped onto a carbon film, and dried before testing. The accelerating voltage was 200 kV, and the magnification was 3000-60000.

[0025] In this invention, preferably, based on the total amount of catalyst, the catalyst contains 15% ≤ w(Al2O3) ≤ 35%, for example, values ​​of 15%, 20%, 25%, 30%, 35%, and any combination thereof. The solid acid alkylation catalyst provided by this invention achieves catalyst shaping by controlling the alumina content in the catalyst and using less binder, thus ensuring that the cell constant of the molecular sieve in the catalyst does not decrease as much as possible. Furthermore, the binder has high dispersibility, ensuring that the solid acid alkylation catalyst has excellent pore structure and high acid content.

[0026] In this invention, from Figure 1 China D and Figure 2 As can be seen from D, such as Figure 1 As shown in Figure D, the catalyst provided by this invention, the aluminum-based binder, and the molecular sieve do not have a clear boundary, and the d value is small, indicating that the aluminum-based binder and the molecular sieve are uniformly mixed and well dispersed, and no obvious alumina clusters were observed; while as Figure 2As shown in Figure D, there is a clear boundary between the molecular sieve and the aluminum-based binder. The small d value indicates that the aluminum-based binder and the molecular sieve are not mixed uniformly and have poor dispersibility. Preferably, the d value of the catalyst is 0.01-5 nm, more preferably 0.01-1 nm, for example, it can be 0.01 nm, 0.02 nm, 0.03 nm, 0.04 nm, 0.05 nm, 0.06 nm, 0.07 nm, 0.08 nm, 0.09 nm, 0.1 nm, 0.15 nm, 0.2 nm, 0.25 nm, 0.3 nm, 0.35 nm, 0.4 nm, 0.45 nm, 0.5 nm, 0.55 nm, 0.6 nm, 0.65 nm, 0.7 nm, 0.75 nm, 0.8 nm, 0.85 nm, 0.9 nm, 0.95 nm, 1 nm, or any value between any two groups. The advantage of this preferred embodiment is that it improves the mixing degree of alumina and molecular sieve to a certain extent, retains the original pore structure of molecular sieve, and enhances the interaction between molecular sieve and alumina binder to increase acid content.

[0027] In this invention, preferably, the aluminum-based binder contains at least a portion of free alumina, and more preferably, the catalyst does not contain free alumina clusters with a particle size exceeding 0.1 nm. It should be noted that free alumina refers to alumina clusters that are not in contact with the molecular sieve grains. Figure 2 Obvious alumina clusters can be observed in the middle D, indicating that the molecular sieve and aluminum-based binder are uniformly dispersed in the catalyst of the present invention. The free alumina particle size in the solid acid alkylation catalyst provided by the present invention is small, indicating that the aluminum-based binder has high dispersibility, which is beneficial to improving the catalytic performance of the catalyst.

[0028] In this invention, the particle size of free alumina was determined by STEM analysis. Specifically, a JEM-ARM200F aberration-corrected transmission electron microscope was used. The sample was uniformly dispersed in ethanol, dropped onto a carbon film, and dried before testing. The accelerating voltage was 200 kV, and the magnification was 3000-60000.

[0029] In this invention, there is no particular limitation on the type of molecular sieve; any molecular sieve with a regular structure conventionally defined in the art is applicable to this invention. Preferably, the molecular sieve is an aluminosilicate molecular sieve, preferably selected from at least one of type A molecular sieve, type Y molecular sieve, type X molecular sieve, type MOR molecular sieve, and ZSM-5 molecular sieve, and more preferably type Y molecular sieve and / or type MOR molecular sieve.

[0030] The solid acid alkylation catalyst provided by this invention has excellent pore structure characteristics. While ensuring a high content of active components in the molecular sieve, it also has a high micropore volume ratio, which is beneficial to improving the catalytic performance of the catalyst. Preferably, the micropore volume of the catalyst accounts for more than 60% of the total pore volume, more preferably more than 75%, and even more preferably 80-95%.

[0031] In this invention, the micropore volume of the catalyst was measured by a low-temperature Ar adsorption method. The specific test conditions were: the sample was evacuated to a vacuum of 330°C until 10... -3 The catalyst was desorbed by holding at low temperature (Pa) for 9 hours to remove adsorbed water and other impurities. The adsorption and desorption of Ar in the purified sample under different specific pressures (p / p0) were tested at liquid nitrogen temperature (-196℃). The micropore volume of the sample was then calculated using the Horvath-Kawazoe (HK) method.

[0032] The solid acid alkylation catalyst provided by this invention has a large specific surface area, which is beneficial for improving the alkylation performance of the catalyst. Preferably, the specific surface area of ​​the catalyst is greater than 400 m². 2 / g, further preferably 550-1000m 2 / g, more preferably 550-800m 2 / g.

[0033] In this invention, the specific surface area of ​​the catalyst was measured by the N2 low-temperature adsorption-desorption BET method. The specific test conditions were as follows: the sample was evacuated to 330°C to a vacuum of 10... -3 The catalyst was desorbed by holding the sample at low temperature (Pa) for 9 hours to remove adsorbed water and other impurities. The adsorption and desorption of N2 on the purified sample were tested at liquid nitrogen temperature (-196℃) under different specific pressures (p / p0), and N2 adsorption-desorption isotherms were obtained. The specific surface area was then calculated using the two-parameter BET formula.

[0034] In this invention, preferably, the total acidity of the catalyst is 1000-5000 μmmol / g, more preferably 2000-4000 μmmol / g. The advantage of this preferred embodiment is that the acidic sites of the active component, i.e., the molecular sieve, are well preserved in the catalyst, and the highly dispersed binder interacts with the molecular sieve, thereby enhancing the total acidity of the resulting catalyst.

[0035] In this invention, the total acidity of the catalyst was determined by NH3 temperature-programmed desorption. The specific test conditions were as follows: 0.1 g of sample with a particle size of 20-40 mesh was weighed and placed in a sample tube, which was then placed in a thermal conductivity furnace. He gas at a flow rate of 50 mL / min was used as the carrier gas to raise the temperature to 600 °C and purge for 1 h to remove adsorbates from the sample surface. The temperature was then lowered to 100 °C and held for 30 min. Adsorption was then performed using an NH3 / He mixed gas (10% NH3 + 90% He) for 30 min, followed by purging with He gas for 90 min until the baseline stabilized, thus removing NH3 physically adsorbed on the sample surface. Desorption was then performed by raising the temperature to 600 °C at a rate of 10 °C / min. The amount of NH3 desorbed was measured using a TCD detector during the NH3 desorption process.

[0036] In this invention, preferably, the skeletal aluminum index of the catalyst is 33-37, more preferably 35-37. The advantage of this preferred embodiment is that the molecular sieve itself has a complete framework, and the highly dispersed aluminum-based binder can interact well with the molecular sieve, increasing the skeletal aluminum index.

[0037] In this invention, the framework aluminum index is defined as N-Al, and its calculation formula is: N-Al=192 / (A+1), where A is the framework silicon-to-aluminum ratio. The framework silicon-to-aluminum ratio of the catalyst is measured by solid magic-angle rotating nuclear magnetic resonance (NMR). The specific test conditions are: a 7mm dual-resonance probe, a Φ7mm ZrO2 rotor, a resonance frequency of 99.3MHz, a magic-angle rotation speed of 5kHz, a pulse width of 1.8μs (corresponding to a 20° chamfer), a cycle delay time of 3s, and approximately 3000 scans.

[0038] In this invention, preferably, the sodium oxide content in the catalyst is no more than 0.5 wt%, and more preferably no more than 0.2 wt%, based on the weight of the catalyst.

[0039] A second aspect of the present invention provides a method for preparing a solid acid alkylation catalyst, wherein the method includes the following steps:

[0040] (1) The solid-liquid mixture containing the binder precursor solution and the molecular sieve is subjected to a hydrolysis reaction with water, and then solid-liquid separation is performed to obtain a solid mixture;

[0041] (2) The solid mixture described in step (1) is mixed with a peptide solvent, an additive and water, molded, dried and calcined to obtain a solid acid alkylation catalyst;

[0042] The binder precursor is selected from at least one of organic aluminum alkoxides.

[0043] The method provided by this invention involves mixing an organic aluminum alcohol binder precursor solution with a molecular sieve, followed by hydrolysis and molding. Each step is performed sequentially to improve the degree of binder dispersion. Through a one-step molding method, a solid acid alkylation catalyst with good microporous structure, acidity, and high dispersibility can be prepared.

[0044] In this invention, the range of types of binder precursors is relatively wide. Preferably, in step (1), the binder precursor is selected from organic aluminum alkoxides with fewer than 15 carbon atoms, and is preferably at least one of aluminum ethoxide, aluminum isopropoxide, and aluminum sec-butoxide.

[0045] In this invention, preferably, in step (1), the binder precursor solution is prepared by dissolving the binder precursor in an organic solvent under ultrasonic conditions. By dissolving the binder precursor in an organic solvent, it is possible to ensure that the substances obtained during the subsequent hydrolysis reaction are evenly dispersed.

[0046] In this invention, a wide range of organic solvents can be selected. Preferably, in step (1), the organic solvent is selected from at least one of methanol, ethanol, isopropanol, and sec-butanol. In a preferred embodiment, the type of organic solvent is determined according to the type of binder precursor. For example, when the binder precursor is aluminum ethoxide, ethanol is selected as the organic solvent. Through this preferred embodiment, the content of impurities in the catalyst can be reduced.

[0047] In this invention, there is no particular limitation on the amount of binder precursor and organic solvent used. Preferably, in step (1), the amount of binder precursor and organic solvent used is such that the mass fraction of the binder precursor solution, calculated as oxide, is 5-50%, more preferably 10-20%. For example, preferably, the mass ratio of binder precursor to organic solvent, calculated as oxide, is 0.05-0.5:1, more preferably 0.1-0.2:1.

[0048] In this invention, the binder precursor, organic aluminum alkoxide, is mixed with an organic solvent under ultrasonic conditions to form a solution containing the binder precursor. There are no particular limitations on the mixing conditions, as long as a stable and homogeneous solution can be obtained. Preferably, in step (1), the ultrasonic conditions include: a temperature of 15-70°C and a time of 1-6 hours, preferably 2-5 hours.

[0049] The specific types of molecular sieves in this invention have already been described in the first aspect and will not be repeated here.

[0050] In this invention, preferably, the silicon-to-aluminum molar ratio of the molecular sieve is 4-5.

[0051] In this invention, by controlling the amounts of molecular sieve and binder precursor solution, a high content of the active component of molecular sieve in the catalyst is achieved. Preferably, in step (1), the mass ratio of the molecular sieve to the binder precursor solution (based on oxides) is 10:1-2:1 on a dry basis, and more preferably 6:1-4:1. Within this preferred range, both a high content of the active component in the catalyst and the catalyst strength meeting industrial requirements can be ensured.

[0052] In this invention, a binder precursor solution is mixed with a molecular sieve to obtain a solid-liquid mixture of the binder precursor solution and the molecular sieve. This invention does not particularly limit the mixing conditions of the molecular sieve and the binder precursor solution. Preferably, in step (1), the mixing conditions include: a temperature of 25-65℃ and a time of 0.5-5h. By mixing the molecular sieve and the binder precursor solution, the binder precursor is highly dispersed, thereby achieving the preparation of a high-strength microporous catalyst material.

[0053] In this invention, by adding water and controlling the amount of water added, the binder precursor is completely hydrolyzed to obtain a pseudo-thin aqueous phase alumina with better pore structure properties. Preferably, in step (1), the mass ratio of the solid-liquid mixture containing the binder precursor solution and the molecular sieve to water is 50:1-5:1, more preferably 50:1-25:1.

[0054] In this invention, preferably, in step (1), the water is added dropwise to the solid-liquid mixture containing the binder precursor solution and the molecular sieve. Based on the mass of the solid-liquid mixture containing the binder precursor solution and the molecular sieve, the drop rate of the water is 0.1-5 drops / s. By controlling the method of water addition, this invention can obtain pseudo-thin aqueous alumina with superior pore structure properties, ensuring that the catalyst maintains a high micropore ratio and acid content during subsequent forming processes.

[0055] In this invention, preferably, in step (1), the hydrolysis reaction is carried out in the presence of an alkaline compound, which is selected from at least one of ammonia, tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrapropylammonium hydroxide. An advantage of this preferred embodiment is that the selected alkaline regulator can be more easily removed during subsequent calcination.

[0056] In this invention, the selection range of conditions for the hydrolysis reaction is relatively wide. Preferably, in step (1), the conditions for the hydrolysis reaction include: a temperature of 40-85℃, a reaction time of 0.5-20h, and a pH of 8-11; more preferably, the conditions for the hydrolysis reaction include: a temperature of 40-80℃, a reaction time of 2-10h, and a pH of 9-11.

[0057] In this invention, there is no particular limitation on the solid-liquid separation method in step (1). For example, it can be filtration, washing, or drying as conventionally defined in the art. In this invention, there is no particular limitation on the specific operation method and conditions of filtration, washing, and drying. Those skilled in the art can choose according to actual needs.

[0058] In this invention, the range of types of adhesive solvents is relatively wide; any adhesive solvent that serves the functions of lubrication and pore formation is suitable for this invention. Preferably, in step (2), the adhesive solvent is selected from at least one of hydrochloric acid, nitric acid, oxalic acid, and citric acid.

[0059] In this invention, the range of suitable amounts of adhesive solvent is relatively wide. Preferably, in step (2), the mass ratio of the solid mixture to the adhesive solvent is 100-50:1.

[0060] In this invention, the adhesive solvent exists in the form of an acidic solution, and preferably, the mass concentration of the adhesive solvent is 1-10% by mass.

[0061] In this invention, the range of types of additives is relatively wide. Preferably, in step (2), the additive is selected from at least one of guar gum powder, methylcellulose, polyether, polyvinyl alcohol, cyclodextrin, and chitosan.

[0062] In this invention, the range of dosage selection for the additives is relatively wide. Preferably, in step (2), the mass ratio of the solid mixture to the additives is 100-50:1.

[0063] In this invention, there is no particular limitation on the amount of water used in step (2), as long as it is sufficient to ensure that the solid mixture, including the molecular sieve and the binder, is mixed evenly. Preferably, the weight ratio of the water to the total dry weight of the solid mixture (including the molecular sieve and the binder) is 0.8-1.2:1.

[0064] In this invention, the range of drying conditions is relatively wide. Preferably, in step (2), the drying conditions include: a drying temperature of 80-150℃ and a drying time of 1-12h; more preferably, the drying temperature is 100-150℃ and the drying time is 4-8h.

[0065] In this invention, there is no particular limitation on the molding method in step (2). Molding methods conventionally defined in the art are applicable to this invention, and those skilled in the art can choose according to actual needs.

[0066] In this invention, the dried mixed molding is calcined to remove the additives therein, and the calcination conditions are selected within a wide range. Preferably, in step (2), the calcination conditions include: a calcination temperature of 450-650℃ and a calcination time of 1-12h; more preferably, the calcination temperature is 500-600℃ and the drying time is 1-3h.

[0067] In this invention, preferably, the calcination is carried out in an air atmosphere, a nitrogen atmosphere, or a water vapor atmosphere.

[0068] A third aspect of the present invention provides a solid acid alkylation catalyst prepared by the method described in the second aspect.

[0069] The fourth aspect of this invention provides the application of the solid acid alkylation catalyst described in the first or third aspect in an alkylation reaction.

[0070] The present invention will be described in detail below through embodiments. Unless otherwise specified, all raw materials used in the following embodiments are commercially available products.

[0071] Example 1

[0072] (1) Aluminum isopropoxide (calculated as oxide) and anhydrous ethanol were mixed at a mass ratio of 1:6, and the mixture was sonicated at 65°C for 4 hours to obtain a homogeneous and stable solution.

[0073] (2) HY molecular sieve (by dry weight) with a silicon-aluminum molar ratio of 4.0 was mixed with the above solution (by oxide) at a mass ratio of 5:1, and stirred at 65°C for 1 hour to obtain a solid-liquid mixture.

[0074] (3) Add pure water dropwise to the above solid-liquid mixture at a rate of 30 drops / min, wherein the mass ratio of pure water to the above solid-liquid mixture is 1:10, adjust the pH to 10 with ammonia water, stir at 65℃ for 1h, then filter, wash, and dry at 110℃ for 4h to obtain a solid mixture;

[0075] (4) Add 3wt% guar gum powder and 3wt% nitric acid (5% by mass) to the above solid mixture, add pure water at a ratio of 1:1 between the weight of water and the total dry weight of the solid mixture, mix evenly, extrude and mold, dry at 110°C for 4 hours, and then calcine at 550°C for 3 hours in air atmosphere to obtain catalyst C-1.

[0076] Figure 1 These are TEM-EDX energy dispersive spectroscopy (EDX) images of the catalyst from Example 1. A is the TEM morphology of the catalyst, B is the aluminum elemental distribution map, C is the silicon elemental distribution map (silicon is only present in the molecular sieve, which can determine the molecular sieve grain size), and D is the silicon-aluminum elemental overlap map of B and C. Figure 1 As can be seen from A, B, and D, the catalyst molecular sieve and aluminum-based binder provided by this invention do not have a clear boundary, and the d value is small, indicating that the molecular sieve and binder are highly dispersed in the catalyst.

[0077] Figure 3 MAS NMR of the catalyst in Example 1 27 The spectrum shows that catalyst C-1 did not exhibit characteristic peaks belonging to the γ-Al2O3 phase at chemical shifts of 9 ppm and 70 ppm, which also indicates that the alumina was highly dispersed and did not exhibit aggregated clusters.

[0078] Example 2

[0079] (1) Aluminum isopropoxide (calculated as oxide) and anhydrous ethanol were mixed at a mass ratio of 1:6, and the mixture was sonicated at 45℃ for 4 hours to obtain a homogeneous and stable solution.

[0080] (2) HY molecular sieve (by dry weight) with a silicon-aluminum molar ratio of 4.5 was mixed with the above solution (by oxide) at a mass ratio of 5:1, and stirred at 45°C for 1 hour to obtain a solid-liquid mixture.

[0081] (3) Add pure water to the above solid-liquid mixture at 15 drops / min, wherein the mass ratio of pure water to the above solid-liquid mixture is 1:10, adjust the pH to 10 with ammonia, stir at 65℃ for 1h, then filter, wash, and dry at 110℃ for 4h to obtain a solid mixture.

[0082] (4) Add 3wt% guar gum powder and 3wt% nitric acid (5% by mass) to the above solid mixture, add pure water at a ratio of 1:1 between the weight of water and the total dry weight of the solid mixture, mix evenly, extrude and mold, dry at 110°C for 4 hours, and then calcine the molded carrier at 550°C for 3 hours in an air atmosphere to obtain catalyst C-2.

[0083] Example 3

[0084] (1) Aluminum isopropoxide (calculated as oxide) and anhydrous ethanol were mixed at a mass ratio of 1:6, and the mixture was sonicated at 65°C for 4 hours to obtain a homogeneous and stable solution.

[0085] (2) MOR molecular sieve (based on dry weight) with a silicon-aluminum molar ratio of 4.0 was mixed with the above solution (based on oxides) at a mass ratio of 6:1, and stirred at 65°C for 1 hour to obtain a solid-liquid mixture.

[0086] (3) Add pure water to the above solid-liquid mixture at a rate of 30 drops / min, wherein the mass ratio of pure water to the above solid-liquid mixture is 1:12. Adjust the pH to 10 with ammonia water. Stir at 65°C for 1 hour, then filter, wash, and dry at 110°C for 4 hours to obtain a solid mixture.

[0087] (4) Add 3wt% guar gum powder and 3wt% nitric acid (5% by mass) to the above solid mixture, add pure water at a ratio of 1:1 between the weight of water and the total dry weight of the solid mixture, mix evenly, extrude and mold, dry at 110°C for 4 hours, and then calcine the molded carrier at 550°C for 3 hours in an air atmosphere to obtain catalyst C-3.

[0088] Example 4

[0089] The method of Example 1 is the same, except that in step (3), pure water is added to the solid-liquid mixture all at once, and the rest of the operation remains the same. The resulting catalyst is named C-4.

[0090] Example 5

[0091] The method of Example 3 was followed, except that type A molecular sieve (silicon-aluminum molar ratio of 2) was used, and the other conditions were kept the same as in Example 3. The resulting catalyst was named C-5.

[0092] Example 6

[0093] The method of Example 1 is the same, except that in step (2), the mass ratio of HY molecular sieve (based on dry weight) with a silicon-aluminum molar ratio of 4.5 to the stable solution (based on oxides) in step (1) is 2:1, and the rest of the operation remains unchanged. The resulting catalyst is named C-6.

[0094] Comparative Example 1

[0095] HY molecular sieve with a silicon-to-aluminum molar ratio of 4.5 was mixed with pseudoboehmite at a dry weight percentage of 80:20. 3 wt% guar gum powder and 3 wt% nitric acid (mass concentration 5%) were added respectively. Deionized water was added at a dry weight ratio of 5:1 to the total dry weight of water and other mixtures. After mixing evenly, the mixture was extruded and dried at 110℃ for 4 h. Then, it was calcined at 550℃ for 3 h in air atmosphere to obtain catalyst D-1.

[0096] Figure 2 The images show the TEM-EDX energy dispersive spectroscopy (EDX) spectra of the catalyst in Comparative Example 1. A is the TEM morphology of the catalyst, B is the aluminum elemental distribution map, C is the silicon elemental distribution map (silicon is only present in the molecular sieve, allowing for the determination of the molecular sieve grain size), and D is the silicon-aluminum elemental overlap map between B and C. Figure 2As can be seen from A, B, and D, the catalyst molecular sieve in Comparative Example 1 has a clear boundary with the aluminum-based binder, and the combination... Figure 2 The position indicated by the middle circle shows the presence of alumina clusters in the catalyst of Comparative Example 1.

[0097] Figure 3 MAS NMR of the catalyst in Comparative Example 1 27 The spectrum shows that catalyst D-1 exhibits characteristic peaks at chemical shifts of 9 ppm and 70 ppm, which also indicate that alumina forms aggregated clusters.

[0098] The alumina content and structural parameters of the catalysts prepared in the above examples and comparative examples are shown in Table 1.

[0099] Table 1

[0100]

[0101] Test case

[0102] The catalysts prepared in the above examples and comparative examples were subjected to alkylation reactions, and the results are listed in Table 2. C8 selectivity represents the average result over the cycle life. The reaction conditions were: a molar ratio of isobutane to 1-butene of 150, a reaction temperature of 75°C, a reaction pressure of 3 MPa, and a mass hourly space velocity (HHSV) of 1-butene of 0.5 h⁻¹. -1 The detection of 1-butene in the product indicates catalyst deactivation, and the reaction time before catalyst deactivation is defined as catalyst lifetime.

[0103] Table 2

[0104] Catalyst number Catalyst lifetime (h) <![CDATA[C8 Selectivity (%)]]> Example 1 C-1 34 85 Example 2 C-2 32 79 Example 3 C-3 34 78 Example 4 C-4 30 75 Example 5 C-5 28 70 Example 6 C-6 36 82 Comparative Example 1 D-1 12 60

[0105] As can be seen from the table above, the catalyst prepared by the present invention performs excellently in the isobutane-butene alkylation reaction, with a lifetime nearly twice that of Comparative Example 1 and a C8 selectivity that can be increased by up to 25 percentage points.

[0106] 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. A solid acid alkylation catalyst for alkylation reactions, characterized in that, The catalyst comprises a molecular sieve and an aluminum-based binder, wherein, based on the total amount of catalyst, 10% ≤ w (Al2O3)≤40%, w (Al2O3) represents the mass fraction of Al2O3 in the catalyst as measured by XRF, wherein the Al2O3 comprises alumina in the aluminum-based binder and alumina in the molecular sieve; the d value of the catalyst is 0.1-5 nm, wherein the d value represents the thickness of the aluminum-based binder in the catalyst along the edge of the crystal plane of the molecular sieve grain as measured by TEM; the molecular sieve is selected from at least one of type A molecular sieve, type Y molecular sieve, type X molecular sieve, type MOR molecular sieve and ZSM-5 molecular sieve; the micropore volume of the catalyst accounts for more than 60% of the total pore volume.

2. The catalyst according to claim 1, wherein, Based on the total amount of catalyst, 15% ≤ w (Al2O3)≤35%.

3. The catalyst according to claim 1, wherein, The aluminum-based binder contains at least a portion of free aluminum oxide.

4. The catalyst according to claim 3, wherein, The catalyst does not contain free alumina clusters with a particle size exceeding 0.01 nm.

5. The catalyst according to claim 1, wherein, The molecular sieve is a Y-type molecular sieve and / or a MOR-type molecular sieve.

6. The catalyst according to claim 1, wherein, The catalyst has a micropore volume that accounts for more than 75% of the total pore volume.

7. The catalyst according to claim 6, wherein, The catalyst has a micropore volume that accounts for 80-95% of the total pore volume.

8. The catalyst according to claim 1, wherein, The catalyst has a specific surface area greater than 400 m². 2 / g.

9. The catalyst according to claim 8, wherein, The catalyst has a specific surface area of ​​550-1000 m². 2 / g.

10. The catalyst according to claim 1, wherein, The total acidity of the catalyst is 1000-5000 μmmol / g.

11. The catalyst according to claim 10, wherein, The total acidity of the catalyst is 2000-4000 μmmol / g.

12. The catalyst according to claim 1, wherein, The skeletal aluminum index of the catalyst is 33-37.

13. The catalyst according to claim 12, wherein, The skeletal aluminum index of the catalyst is 35-37.

14. A method for preparing the catalyst according to any one of claims 1-13, wherein, The method includes the following steps: (1) The solid-liquid mixture containing the binder precursor solution and the molecular sieve is subjected to a hydrolysis reaction with water, and then solid-liquid separation is performed to obtain a solid mixture; (2) The solid mixture described in step (1) is mixed with a peptide solvent, an additive and water, molded, dried and calcined to obtain a solid acid alkylation catalyst; The binder precursor is selected from at least one of organic aluminum alkoxides; The molecular sieve is selected from at least one of type A molecular sieve, type Y molecular sieve, type X molecular sieve, type MOR molecular sieve and ZSM-5 molecular sieve.

15. The method according to claim 14, wherein, In step (1), the binder precursor is selected from organic aluminum alkoxides with less than 15 carbon atoms.

16. The method according to claim 15, wherein, In step (1), the binder precursor is selected from at least one of aluminum ethoxide, aluminum isopropoxide, and aluminum sec-butoxide.

17. The method of claim 14, wherein, In step (1), the binder precursor solution is prepared by dissolving the binder precursor in an organic solvent under ultrasonic conditions.

18. The method according to claim 17, wherein, The organic solvent is selected from at least one of methanol, ethanol, isopropanol and sec-butanol.

19. The method according to claim 18, wherein, The amount of the binder precursor and the organic solvent is such that the mass fraction of the binder precursor solution, calculated as oxides, is 5-50%.

20. The method according to claim 19, wherein, The amount of the binder precursor and the organic solvent is such that the mass fraction of the binder precursor solution, calculated as oxides, is 10-20%.

21. The method according to claim 17, wherein, In step (1), the conditions for ultrasound include: temperature of 15-70℃ and time of 1-6h.

22. The method according to claim 14, wherein, In step (1), the molecular sieve is a Y-type molecular sieve and / or a MOR-type molecular sieve.

23. The method according to claim 14, wherein, In step (1), the mass ratio of the molecular sieve on a dry basis to the binder precursor solution on an oxide basis is 10:1-2:

1.

24. The method according to claim 23, wherein, In step (1), the mass ratio of the molecular sieve on a dry basis to the binder precursor solution on an oxide basis is 6:1 to 4:

1.

25. The method according to claim 14, wherein, In step (1), the mass ratio of the binder precursor solution and the solid-liquid mixture of molecular sieve to water is 50:1-5:

1.

26. The method of claim 25, wherein, In step (1), the mass ratio of the binder precursor solution and the solid-liquid mixture of molecular sieve to water is 50:1-25:

1.

27. The method according to claim 14, wherein, In step (1), the water is added to the solid-liquid mixture containing the binder precursor solution and the molecular sieve by dripping. Based on the mass of the solid-liquid mixture containing the binder precursor solution and the molecular sieve, the dripping rate of the water is 0.1-5 drops / s.

28. The method according to claim 14, wherein, In step (1), the hydrolysis reaction is carried out in the presence of an alkaline compound selected from at least one of ammonia, tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrapropylammonium hydroxide.

29. The method according to claim 28, wherein, In step (1), the conditions for the hydrolysis reaction include: a temperature of 40-85℃, a reaction time of 0.5-20h, and a pH of 8-11.

30. The method of claim 14, wherein, In step (2), the adhesive solvent is selected from at least one of hydrochloric acid, nitric acid, oxalic acid, hydrofluoric acid, fluorosilicic acid and citric acid.

31. The method according to claim 14, wherein, In step (2), the mass ratio of the solid mixture to the adhesive solvent is 100-50:

1.

32. The method according to claim 14, wherein, In step (2), the auxiliary agent is selected from at least one of guar gum powder, methylcellulose, polyether, polyvinyl alcohol, cyclodextrin and chitosan.

33. The method according to claim 14, wherein, In step (2), the mass ratio of the solid mixture to the additive is 100-50:

1.

34. The method according to claim 14, wherein, In step (2), the drying conditions include: a drying temperature of 80-150℃ and a drying time of 1-12h.

35. The method according to claim 14, wherein, In step (2), the calcination conditions include: a calcination temperature of 450-650℃ and a calcination time of 1-12h.

36. The use of the solid acid alkylation catalyst according to any one of claims 1-13 in alkylation reactions.

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