Alkylation method

Abstract

The invention relates to the field of alkylation, and discloses an alkylation method. The alkylation method comprises the following steps: under alkylation reaction conditions, carrying out alkylation reaction on olefin and alkylate in the presence of a solid acid alkylation catalyst, the solid acid alkylation catalyst comprises a molecular sieve and an aluminum-based adhesive, by taking the total amount of the catalyst as a reference, in the catalyst, w (Al2O3) is more than or equal to 10% and less than or equal to 40%, w (Al2O3) represents the mass fraction of Al2O3 in the catalyst measured by an XRF (X-Ray Fluorescence) method, and Al2O3 comprises alumina in the aluminum-based adhesive and alumina in the molecular sieve; the d value of the catalyst is less than or equal to 10nm, and the d value represents the thickness of the aluminum-based adhesive outwards along the crystal face edge of the molecular sieve crystal grain in the catalyst measured by a TEM (Transmission Electron Microscope) method. According to the method, the high-dispersity solid acid alkylation catalyst is selected, so that the service life of the catalyst in the alkylation reaction is prolonged, and the selectivity of a target product is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of alkylation, and in particular to an alkylation method. Background Art

[0002] In order to reduce the exhaust gas emission of fuel vehicles, the quality upgrade of vehicle fuel has been accelerated. Producing clean fuel with low sulfur, low olefins and low aromatics to reduce the emission of harmful substances in automobile exhaust has become the development theme of clean gasoline upgrade today. At present, the alkylation process technologies used and under development at home and abroad include hydrofluoric acid method, sulfuric acid method, composite ionic liquid method, solid acid method, etc. The solid acid alkylation process is safer and greener than the liquid acid alkylation process, and has become a new development direction of alkylation process in industrial application.

[0003] Chinese patent application CN105126900A discloses a gasoline alkylation catalyst and its preparation method. The catalyst uses MCM-22 molecular sieve modified with TiO2 having a mesoporous structure as a carrier and SO4 2- PO4 3- As the main active component, the content of TiO2 is 20-50wt% of the total weight of the catalyst carrier, SO4 2- PO4 3- The total content of SO4 is 15-35wt% of the total weight of the catalyst, and SO4 2- With PO4 3- The molar ratio is 1:(1.3-3.0). The introduction of H3PO4 can form solid phosphoric acid with the catalyst carrier to further enhance the alkylation reaction process and improve the selectivity of C8 hydrocarbons.

[0004] Chinese patent application CN112387301A discloses a C4 alkylation catalyst containing Y molecular sieve and a preparation method thereof, wherein the catalyst comprises molybdenum-based sulfide powder and HY molecular sieve raw powder, and the content of the molybdenum-based sulfide powder is 0.1-40wt% based on the total mass of the C4 alkylation catalyst containing Y molecular sieve; wherein the particle size of the HY molecular sieve raw powder is less than 0.4μm. The HY molecular sieve alkylation catalyst supported by molybdenum sulfide is prepared and synthesized by directly adding molybdenum sulfide powder, which has strong alkylation reaction performance and stability and can improve the life of the alkylation catalyst.

[0005] In the traditional preparation method of molecular sieves for alkylation reactions, active components, clay or binders, and additives are generally mixed and then molded to obtain a molded carrier to maintain the strength and size requirements of the molecular sieve. The content of the active components of the molecular sieve in the mixture is required to be low (generally less than 70%), and the added binder must be mixed evenly to obtain a good bonding effect. It will also introduce a mesoporous structure into the catalyst, changing the pore structure of the catalytic material and thus affecting its catalytic properties. Summary of the invention

[0006] The purpose of the present invention is to overcome the problem of rapid deactivation of solid acid catalysts used in alkylation reactions in the prior art, and to provide an alkylation method. The method uses a solid acid alkylation catalyst with a high content of active components and high dispersibility, thereby improving the service life of the catalyst and the selectivity of the target product in the alkylation reaction.

[0007] In order to achieve the above object, the present invention provides an alkylation method, wherein the method comprises: under alkylation reaction conditions, subjecting olefins and alkylates to an alkylation reaction in the presence of a solid acid alkylation catalyst;

[0008] The solid acid alkylation catalyst comprises a molecular sieve and an aluminum-based binder. Based on the total amount of the catalyst, in the catalyst, 10%≤w(Al2O3)≤40%, w(Al2O3) represents the mass fraction of Al2O3 in the catalyst measured by an XRF method, and the Al2O3 comprises aluminum oxide in the aluminum-based binder and aluminum oxide in the molecular sieve; the d value of the catalyst is ≤10nm, and the d value represents the thickness of the aluminum-based binder from the edge of the crystal surface of the molecular sieve grains in the catalyst to the outside measured by a TEM method.

[0009] Preferably, the catalyst preparation method comprises the following steps:

[0010] (1) subjecting a solid-liquid mixture containing a binder precursor solution and a molecular sieve to a hydrolysis reaction with water, and then performing solid-liquid separation to obtain a solid mixture;

[0011] (2) mixing the solid mixture of step (1) with a peptizing agent, an auxiliary agent and water to form a solid acid alkylation catalyst through drying and calcining;

[0012] The binder precursor is selected from at least one of organic alcohol aluminums.

[0013] The method provided by the invention selects a solid acid alkylation catalyst with high dispersibility, which significantly improves the service life of the catalyst and the selectivity of the target product in the alkylation reaction.

[0014] Preferably, in the preparation method of the solid acid alkylation catalyst, organic alcohol aluminum is used as a binder precursor and is directly mixed with the molecular sieve and then hydrolyzed and formed. A catalyst with high strength, high activity components and high dispersion can be obtained through a one-step process. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the TEM-EDX spectrum analysis diagram of the catalyst in Example 1 ( Figure 1 A is the TEM image of the catalyst. Figure 1 B is the distribution diagram of aluminum element. Figure 1 C is the distribution diagram of silicon element. Figure 1 D in the figure is the overlapping distribution diagram of silicon and aluminum elements);

[0016] Figure 2 This is the TEM-EDX spectrum analysis diagram of the catalyst in Comparative Example 1 ( Figure 2 A is the TEM image of the catalyst. Figure 2 B is the distribution diagram of aluminum element. Figure 2 C is the distribution diagram of silicon element. Figure 2 D in the figure is the overlapping distribution diagram of silicon and aluminum elements);

[0017] Figure 3 The MAS NMR of the catalysts of Example 1 and Comparative Example 1 is 7 Al spectrum. DETAILED DESCRIPTION

[0018] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0019] The present invention provides an alkylation method, wherein the method comprises: under alkylation reaction conditions, subjecting olefins and alkylates to an alkylation reaction in the presence of a solid acid alkylation catalyst;

[0020] The solid acid alkylation catalyst comprises a molecular sieve and an aluminum-based binder. Based on the total amount of the catalyst, in the catalyst, 10%≤w(Al2O3)≤40%, w(Al2O3) represents the mass fraction of Al2O3 in the catalyst measured by an XRF method, and the Al2O3 comprises aluminum oxide in the aluminum-based binder and aluminum oxide in the molecular sieve; the d value of the catalyst is ≤10nm, and the d value represents the thickness of the aluminum-based binder from the edge of the crystal surface of the molecular sieve grains in the catalyst to the outside measured by a TEM method.

[0021] The method provided by the invention selects a solid acid alkylation catalyst with high dispersibility, which significantly improves the service life of the catalyst and the selectivity of the target product in the alkylation reaction.

[0022] In the present invention, W(Al2O3) is measured by semi-quantitative element analysis using a ZSX100E X-ray fluorescence spectrometer produced by Rigaku. The specific test conditions are: tungsten target (excitation voltage 40kV, excitation current 250Ma). The sample powder is pressed into tablets, and the applied pressure is generally 500-1000KPa.

[0023] In the present invention, the d value is measured by using a JEM-ARM200F spherical aberration corrected transmission electron microscope. The specific test method is: the sample is uniformly dispersed with ethanol and then dripped onto the carbon film and dried, and then tested. The acceleration voltage is 200 kV and the magnification is 3000-60000.

[0024] In the present invention, preferably, based on the total amount of the catalyst, in the catalyst, 15%≤w(Al2O3)≤35%, for example, it can be 15%, 20%, 25%, 30%, 35% and values ​​between any two groups. The solid acid alkylation catalyst provided by the present invention can realize catalyst molding by controlling the content of alumina in the catalyst with less binder, thereby ensuring that the unit cell constant of the molecular sieve in the catalyst does not decay as much as possible, and the binder is highly dispersible, which can ensure that the solid acid alkylation catalyst has an excellent pore structure and a high acid content.

[0025] In the present invention, from Figure 1 Medium D and Figure 2 As can be seen from D, Figure 1 As shown in D, there is no obvious boundary between the aluminum-based binder and the molecular sieve of the catalyst provided by the present invention, and the d value is small, indicating that the aluminum-based binder and the molecular sieve are evenly mixed and have good dispersion, and no obvious alumina clusters are observed; and as shown in Figure 2As shown in D, the molecular sieve and the aluminum-based binder have a clear boundary d value is small, indicating that the aluminum-based binder and the molecular sieve are unevenly mixed and have poor dispersibility. Preferably, the d value of the catalyst is 0.01-5nm, more preferably 0.01-1nm, for example, it can be 0.01nm, 0.02nm, 0.03nm, 0.04nm, 0.05nm, 0.06nm, 0.07nm, 0.08nm, 0.09nm, 0.1nm, 0.15nm, 0.2nm, 0.25nm, 0.3nm, 0.35nm, 0.4nm, 0.45nm, 0.5nm, 0.55nm, 0.6nm, 0.65nm, 0.7nm, 0.75nm, 0.8nm, 0.85nm, 0.9nm, 0.95nm, 1nm and values ​​between any two groups. The advantage of adopting this preferred embodiment is that it can improve the mixing degree of alumina and molecular sieve to a certain extent, retain the original pore structure of the molecular sieve, and enhance the interaction between the molecular sieve and the alumina binder to increase the acid content.

[0026] In the present invention, preferably, the aluminum-based binder contains at least a portion of free aluminum oxide, and preferably, the catalyst does not contain free aluminum oxide clusters with a particle size exceeding 0.1 nm. It should be noted that free aluminum oxide refers to aluminum oxide clusters that are not in contact with molecular sieve grains, such as Figure 1 No obvious alumina clusters were observed in D. Figure 2 Obvious alumina clusters can be observed in D, which indicates that the molecular sieve and the aluminum-based binder in the catalyst of the present invention are evenly dispersed. In the solid acid alkylation catalyst provided by the present invention, the particle size of free alumina is relatively small, indicating that the aluminum-based binder has high dispersibility, which is beneficial to improving the catalytic performance of the catalyst.

[0027] In the present invention, the particle size of free aluminum oxide is measured by STEM analysis, and the specific test method is: using a JEM-ARM200F spherical aberration corrected transmission electron microscope. The sample is evenly dispersed with ethanol and then dripped onto a carbon film and dried for testing. The acceleration voltage is 200 kV and the magnification is 3000-60000.

[0028] In the present invention, there is no particular limitation on the type of molecular sieve, and all molecular sieves with regular structures conventionally defined in the art are applicable to the present invention. Preferably, the molecular sieve is an aluminosilicate molecular sieve, preferably at least one selected from A-type molecular sieve, Y-type molecular sieve, X-type molecular sieve, MOR-type molecular sieve and ZSM-5 molecular sieve, more preferably Y-type molecular sieve and / or MOR-type molecular sieve.

[0029] The solid acid alkylation catalyst provided by the present invention has excellent pore structure characteristics. While ensuring a high content of active components of the molecular sieve, the micropores account for a high proportion, which is conducive 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 more preferably 80-95%.

[0030] In the present invention, the micropore volume of the catalyst is measured by Ar low temperature adsorption method. The specific test conditions are: the sample is vacuumed to 10 -3 Pa, and kept at low temperature for 9 hours to remove water and other impurities adsorbed in the catalyst. The adsorption and desorption of Ar on the purified sample under different pressure ratios p / p0 were tested at liquid nitrogen temperature -196°C. The micropore volume of the sample was then calculated using the HK (Horvath-Kawazoe) method.

[0031] The solid acid alkylation catalyst provided by the present invention has a large specific surface area, which is beneficial to improving the alkylation performance of the catalyst. Preferably, the specific surface area of ​​the catalyst is greater than 400 m 2 / g, more preferably 550-1000m 2 / g, more preferably 550-800m 2 / g.

[0032] In the present invention, the specific surface area of ​​the catalyst is measured by the N2 low temperature adsorption and desorption BET method. The specific test conditions are: the sample is vacuumized at 330°C to 10 -3 Pa, and kept at low temperature for 9 hours to remove water and other impurities adsorbed in the catalyst. The adsorption and desorption of N2 by the purified sample under different pressure ratios p / p0 were tested at liquid nitrogen temperature of -196°C, and the N2 adsorption-desorption isotherm was obtained. The specific surface area was then calculated using the two-parameter BET formula.

[0033] In the present invention, preferably, the total acid content of the catalyst is 1000-5000 μmmol / g, more preferably 2000-4000 μmmol / g. The advantage of adopting this preferred embodiment is that the acid sites of the active component in the catalyst, i.e., the molecular sieve, are well preserved, and the highly dispersed binder interacts with the molecular sieve to enhance the total acid content of the obtained catalyst, which is beneficial to the alkylation reaction and improves the alkylation performance.

[0034] In the present invention, the total acid content of the catalyst is measured by the NH3 programmed temperature desorption method, and the specific test conditions are: weigh 0.1g of a sample with a particle size of 20-40 mesh and put it into a sample tube, place it in a thermal conductivity cell heating furnace, use He gas with a flow rate of 50mL / min as a carrier gas to heat it to 600°C and purge it for 1h to remove the adsorbent on the surface of the sample. Then cool it to 100°C, keep the temperature constant for 30min, switch to NH3 / He mixed gas (10% NH3+90% He) for adsorption for 30min, and then switch to He gas to purge for 90min until the baseline is stable to remove NH3 on the surface of the sample by physical adsorption. Desorption is carried out by heating to 600°C at a heating rate of 10°C / min. During the NH3 desorption process, a TCD detector is used to measure the desorption amount of NH3.

[0035] In the present invention, preferably, the framework aluminum index of the catalyst is 33-37, more preferably 35-37. The advantage of adopting 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 to increase the framework aluminum index.

[0036] In the present invention, the framework aluminum index is defined as N-Al, and its calculation formula is: N-Al=192 / (A+1), wherein A is the framework silicon-aluminum ratio, wherein the framework silicon-aluminum ratio of the catalyst is measured by a solid magic angle spinning nuclear magnetic resonance method, and the specific test conditions are: using a 7mm double resonance probe, a Φ7mm ZrO2 rotor. The resonance frequency is 99.3MHz, the magic angle speed is 5kHz, the pulse width is 1.8μs (corresponding to a 20° bevel angle), the cycle delay time is 3s, and the number of scans is about 3000 times.

[0037] In the present invention, preferably, based on the weight of the catalyst, the content of sodium oxide in the catalyst does not exceed 0.5 wt%, preferably does not exceed 0.2 wt%.

[0038] In the present invention, preferably, the catalyst preparation method comprises the following steps:

[0039] (1) subjecting a solid-liquid mixture containing a binder precursor solution and a molecular sieve to a hydrolysis reaction with water, and then performing solid-liquid separation to obtain a solid mixture;

[0040] (2) mixing the solid mixture of step (1) with a peptizing agent, an auxiliary agent and water to form a solid acid alkylation catalyst through drying and calcining;

[0041] The binder precursor is selected from at least one of organic alcohol aluminums.

[0042] The catalyst preparation method provided by the present invention comprises the following steps: uniformly mixing an organic alcohol aluminum binder precursor solution and a molecular sieve, slurrying, and sequentially performing a hydrolysis reaction and molding. The steps in the preparation method are sequentially performed, which can improve the dispersion degree of the binder. Through a one-step molding method, a solid acid alkylation catalyst with good microporous structure, acidity and high dispersibility can be prepared.

[0043] In the present invention, the type of binder precursor can be selected from a wide range. Preferably, in step (1), the binder precursor is selected from an organic aluminum alcohol having a carbon number less than 6, preferably at least one of aluminum ethoxide, aluminum isopropoxide and aluminum sec-butoxide.

[0044] In the present 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 resulting material is evenly dispersed during the subsequent hydrolysis reaction.

[0045] In the present invention, the range of organic solvents is relatively wide. Preferably, in step (1), the organic solvent is selected from at least one of methanol, ethanol, isopropanol and sec-butyl alcohol. Preferably, the type of organic solvent is determined according to the type of binder precursor. For example, when the binder precursor is aluminum ethoxide, the organic solvent is ethanol. By this preferred embodiment, the content of impurities in the catalyst can be reduced.

[0046] In the present invention, there is no particular limitation on the amount of the binder precursor and the organic solvent. Preferably, in step (1), the amount of the binder precursor and the organic solvent is such that the mass fraction of the obtained binder precursor solution calculated as oxide is 5-50%, more preferably 10-20%. For example, preferably, the mass ratio of the binder precursor calculated as oxide to the organic solvent is 0.05-0.5:1, preferably 0.1-0.2:1.

[0047] In the present invention, the binder precursor organic alcohol aluminum and the organic solvent are mixed under ultrasonic conditions to form a binder precursor solution. The present invention has no particular limitation on the mixing conditions, as long as a stable and uniform solution can be obtained. Preferably, in step (1), the ultrasonic conditions include: a temperature of 15-70°C and a time of 1-6h, preferably 2-5h.

[0048] In the present invention, the specific types of molecular sieves have been described in the above content and will not be repeated here.

[0049] In the present invention, preferably, the silicon to aluminum molar ratio of the molecular sieve is 4-5.

[0050] In the present invention, the amount of molecular sieve and binder precursor solution is controlled so that the content of active components of molecular sieve in the catalyst is relatively high. Preferably, in step (1), the mass of the molecular sieve on a dry basis to the binder precursor solution on an oxide basis is 10:1-2:1, and more preferably 6:1-4:1. Within this preferred range, the content of active components in the catalyst can be relatively high, and the catalyst strength can meet industrial requirements.

[0051] In the present invention, a binder precursor solution is mixed with a molecular sieve to obtain a solid-liquid mixture of a binder precursor solution and a molecular sieve. The present 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°C 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.

[0052] In the present invention, the binder precursor is completely hydrolyzed by adding water and controlling the amount of water added to obtain 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, and more preferably 50:1-25:1.

[0053] In the present invention, preferably, in step (1), the water is added dropwise to the solid-liquid mixture containing the binder precursor solution and the molecular sieve, and the water drop rate is 0.1-5 drops / s based on the mass of the solid-liquid mixture containing the binder precursor solution and the molecular sieve. In the present invention, by controlling the water addition method, a pseudo-thin aqueous phase alumina with better pore structure properties can be obtained, so that the catalyst still maintains a higher microporous structure and acid content during the subsequent molding process.

[0054] In the present invention, preferably, in step (1), the hydrolysis reaction is carried out in the presence of an alkaline compound, and the alkaline compound is selected from at least one of ammonia water, tetramethylammonium hydroxide, tetraethylammonium hydroxide and tetrapropylammonium hydroxide. The advantage of adopting this preferred embodiment is that the selected alkaline regulator can be easily removed in the subsequent roasting process.

[0055] In the present invention, the conditions for the hydrolysis reaction can be selected in a wide range. Preferably, in step (1), the conditions for the hydrolysis reaction include: a temperature of 40-85°C, a reaction time of 0.5-20h, and a pH of 8-11; further preferably, the conditions for the hydrolysis reaction include: a temperature of 40-80°C, a reaction time of 2-10h, and a pH of 9-11.

[0056] In the present invention, there is no particular limitation on the method of solid-liquid separation in step (1), and for example, it may be filtration, washing, or drying as conventionally defined in the art. In the present invention, there is no particular limitation on the specific operation methods and conditions of filtration, washing, or drying, and those skilled in the art may select them according to actual needs.

[0057] In the present invention, the peptizing agent has a wide range of choices, and any peptizing agent that can play a role in lubrication and pore formation is applicable to the present invention. Preferably, in step (2), the peptizing agent is selected from at least one of hydrochloric acid, nitric acid, oxalic acid and citric acid.

[0058] In the present invention, the amount of the peptizing agent can be selected in a wide range. Preferably, in step (2), the mass ratio of the solid mixture to the peptizing agent is 100-50:1.

[0059] In the present invention, the peptizing agent is present in the form of acid solution. Preferably, the mass concentration of the peptizing agent is 1-10 mass %.

[0060] In the present invention, the range of the auxiliary agent is relatively wide. Preferably, in step (2), the auxiliary agent is selected from at least one of sesbania powder, methyl cellulose, polyether, polyvinyl alcohol, cyclodextrin and chitosan.

[0061] In the present invention, the dosage of the auxiliary agent can be selected in a wide range. Preferably, in step (2), the mass ratio of the solid mixture to the auxiliary agent is 100-50:1.

[0062] In the present invention, there is no particular limitation on the amount of water used in step (2), as long as the solid mixture including the molecular sieve and the binder can be mixed uniformly. Preferably, the ratio of the weight of the water to the total weight of the solid mixture (including the molecular sieve and the binder) on a dry basis is 0.8-1.2:1.

[0063] In the present invention, the drying conditions can be selected in a wide range. Preferably, in step (2), the drying conditions include: a drying temperature of 80-150°C and a drying time of 1-12 hours; more preferably, a drying temperature of 100-150°C and a drying time of 4-8 hours.

[0064] In the present invention, there is no particular limitation on the molding method in step (2). All molding methods conventionally defined in the art are applicable to the present invention, and those skilled in the art can select one according to actual needs.

[0065] In the present invention, the mixed molded product after drying is calcined to remove the additives therein, and the present invention has a wide range of selection of calcination conditions. Preferably, in step (2), the calcination conditions include: a calcination temperature of 450-650°C and a calcination time of 1-12h; more preferably, the calcination temperature is 500-600°C and the drying time is 1-3h.

[0066] In the present invention, preferably, the calcination is performed in an air atmosphere, a nitrogen atmosphere, or a water vapor atmosphere.

[0067] In the present invention, the alkylate has a wide range of choices, and can be any alkylate conventionally defined in the art. Preferably, the alkylate is selected from at least one of isobutane, benzene, toluene and ethylbenzene, preferably isobutane.

[0068] In the present invention, the olefin type can be selected in a wide range and can be any olefin conventionally defined in the art. Preferably, the olefin is selected from at least one of ethylene, propylene, butene and pentene, more preferably butene.

[0069] In the present invention, the amount of each raw material used in the alkylation reaction is not particularly limited. Preferably, the molar ratio of the alkylate to the olefin is 1-1000:1, more preferably 20-1000:1.

[0070] In the present invention, the conditions of the alkylation reaction are not particularly limited. Preferably, the conditions of the alkylation reaction include: a temperature of 30-200°C, a pressure of 0.5-6 MPa, and a mass space velocity of 0.01-10 h -1 Further preferably, the conditions of the alkylation reaction include: temperature of 10-100°C, pressure of 2-5MPa, mass space velocity of olefin feed of 0.1-1h -1 .

[0071] In the present invention, preferably, the alkylation method further comprises: subjecting the solid acid alkylation catalyst to a reduction treatment under a reducing atmosphere before the alkylation reaction.

[0072] In the present invention, there is no particular limitation on the type of reducing atmosphere. Preferably, the reducing atmosphere is selected from at least one of nitrogen and / or an inert gas.

[0073] In the present invention, there is no particular limitation on the conditions for the reduction treatment. Preferably, the conditions for the reduction treatment include: a reducing atmosphere flow rate of 5-500 mL / (g catalyst·min), a pressure of 0-2 MPa, a heating rate of 0.2-10°C / min, a temperature of 200-600°C, and a time of 2-6 hours.

[0074] The alkylation method provided by the present invention can effectively realize a high-activity reaction at a relatively low temperature, and a highly acidic catalyst can provide more reaction centers, thereby effectively extending the reaction life.

[0075] The present invention will be described in detail below by way of examples. In the following examples, all raw materials used are commercially available unless otherwise specified.

[0076] Example 1

[0077] (1) Aluminum isopropoxide (calculated as oxide) and anhydrous ethanol were mixed in a mass ratio of 1:6, the temperature was 65° C., and ultrasonication was performed for 4 h to obtain a uniform and stable solution;

[0078] (2) mixing HY molecular sieve (calculated on a dry basis) with a silicon-aluminum molar ratio of 4.0 with the above solution (calculated on an oxide basis) at a mass ratio of 5:1, stirring at 65° C. for 1 h to obtain a solid-liquid mixture;

[0079] (3) adding pure water to the solid-liquid mixture at a rate of 30 drops / min, wherein the mass ratio of pure water to the solid-liquid mixture is 1:10, adjusting the pH value to 10 with aqueous ammonia, stirring at 65° C. for 1 h, then filtering, washing, and drying at 110° C. for 4 h to obtain a solid mixture;

[0080] (4) Add 3 wt% of sesbania powder and 3 wt% of nitric acid (mass concentration 5%) to the above solid mixture, add pure water in a ratio of water weight to the total dry weight of the solid mixture of 1:1, mix well and extrude into shape, dry at 110°C for 4 hours, and then calcine at 550°C for 3 hours in an air atmosphere to obtain catalyst C-1.

[0081] Figure 1 1 is the TEM-EDX spectrum analysis diagram of the catalyst in Example 1, A is the TEM morphology diagram of the catalyst, B is the aluminum element distribution diagram, C is the silicon element distribution diagram, silicon element only exists in the molecular sieve, and the molecular sieve grains can be determined, and D is the silicon and aluminum element overlap diagram of B and C. Figure 1 It can be seen from A, B and D that there is no obvious boundary between the catalyst molecular sieve provided by the present invention and the aluminum-based binder, and the d value is small, indicating that the molecular sieve and the binder in the catalyst are highly dispersed.

[0082] Figure 3 The MAS NMR of the catalyst in Example 1 is 27 Spectrum. It can be seen from the figure that catalyst C-1 does not have the characteristic peaks belonging to the γ-Al2O3 phase at chemical shifts 9 and 68, which also shows that the alumina is highly dispersed and does not show aggregated clusters.

[0083] The catalyst prepared in Example 1 was used in a fixed bed reactor to carry out an alkylation reaction of isoparaffin and olefin. The reaction conditions were as follows: the molar ratio of isobutane to mixed butenes (1-butene and 2-butene) was 250, wherein the molar ratio of 1-butene to 2-butene was 1, the reaction temperature was 75° C., the reaction pressure was 2.5 MPa, and the mass space velocity of the mixed butene feed was 0.1 h -1 When mixed butenes are detected in the product, the catalyst is considered to be deactivated, and the reaction time before the catalyst is deactivated is defined as the catalyst cycle life.

[0084] Before the alkylation reaction, the catalyst needs to be reduced in a nitrogen atmosphere. The reduction treatment conditions include: reducing atmosphere flow rate of 300 mL / (g catalyst·min), pressure of 0 MPa, heating rate of 10°C / min, temperature of 500°C, and time of 3 h.

[0085] Example 2

[0086] (1) Aluminum isopropoxide (calculated as oxide) and anhydrous ethanol were mixed in a mass ratio of 1:6, the temperature was 45° C., and ultrasonication was performed for 4 h to obtain a uniform and stable solution;

[0087] (2) mixing HY molecular sieve (calculated on a dry basis) with a silicon-aluminum molar ratio of 4.5 with the above solution (calculated on an oxide basis) at a mass ratio of 5:1, stirring at 45° C. for 1 h to obtain a solid-liquid mixture;

[0088] (3) adding pure water to the solid-liquid mixture at a rate of 15 drops / min, wherein the mass ratio of pure water to the solid-liquid mixture is 1:10, adjusting the pH value to 10 with aqueous ammonia, stirring at 65° C. for 1 h, then filtering, washing, and drying at 110° C. for 4 h to obtain a solid mixture;

[0089] (4) Add 3 wt% of sesbania powder and 3 wt% of nitric acid (mass concentration 5%) to the above solid mixture, add pure water in a ratio of water weight to the total dry weight of the solid mixture of 1:1, mix well and extrude into a 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.

[0090] The alkylation reaction was carried out in accordance with Example 1, except that the alkylation reaction conditions were as follows: the molar ratio of isobutane to mixed butenes (1-butene and 2-butene) was 250, the molar ratio of 1-butene to 2-butene was 2, the reaction temperature was 60° C., the reaction pressure was 3 MPa, and the mass space velocity of the mixed butene feed was 0.1 h -1 .

[0091] Example 3

[0092] (1) Aluminum isopropoxide (calculated as oxide) and anhydrous ethanol were mixed in a mass ratio of 1:6, the temperature was 65° C., and ultrasonication was performed for 4 h to obtain a uniform and stable solution;

[0093] (2) mixing a MOR molecular sieve having a silicon-aluminum molar ratio of 4.0 (calculated on a dry basis) with the above solution (calculated on an oxide basis) in a mass ratio of 6:1, stirring at 65° C. for 1 h to obtain a solid-liquid mixture;

[0094] (3) adding pure water to the solid-liquid mixture at a rate of 30 drops / min, wherein the mass ratio of pure water to the solid-liquid mixture is 1:12, adjusting the pH value to 10 with aqueous ammonia, stirring at 65° C. for 1 h, then filtering, washing, and drying at 110° C. for 4 h to obtain a solid mixture;

[0095] (4) Add 3 wt% of sesbania powder and 3 wt% of nitric acid (mass concentration 5%) to the above solid mixture, add pure water in a ratio of water weight to the total dry weight of the solid mixture of 1:1, mix well and extrude into a 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.

[0096] The alkylation reaction was carried out according to Example 1, except that the alkylation reaction conditions were: reaction temperature was 40° C., reaction pressure was 3 MPa, and the mass space velocity of the mixed butene feed was 0.2 h -1 .

[0097] Example 4

[0098] The method of Example 1 was followed, except that in step (3), pure water was added to the solid-liquid mixture at one time, and the other operations remained unchanged. The obtained catalyst was named C-4.

[0099] The reaction was carried out according to the alkylation reaction method and conditions of Example 1.

[0100] Example 5

[0101] The method of Example 3 was followed, except that type A molecular sieve (silicon to aluminum molar ratio of 2) was used. The other conditions were consistent with those of Example 3, and the resulting catalyst was named C-5.

[0102] The reaction was carried out according to the alkylation reaction method and conditions of Example 1.

[0103] Example 6

[0104] The method of Example 1 is followed, except that in step (2), the mass ratio of HY molecular sieve having a silicon-aluminum molar ratio of 4.5 (calculated on a dry basis) to the stabilized solution of step (1) (calculated on an oxide basis) is 2:1, and the other operations remain unchanged. The resulting catalyst is named C-6.

[0105] The reaction was carried out according to the alkylation reaction method and conditions of Example 1.

[0106] Example 7

[0107] The method of Example 1 was followed, except that the alkylation reaction conditions were: reaction temperature of 120°C, reaction pressure of 2 MPa, and mixed butene feed mass space velocity of 2.5 h -1 .

[0108] Comparative Example 1

[0109] HY molecular sieve with a silicon-aluminum molar ratio of 4.5 and pseudo-boehmite are mixed in a dry weight percentage of 80:20, 3wt% of sesbania powder and 3wt% of nitric acid (mass concentration 5%) are added respectively, and deionized water is added in a ratio of 5:1 between the weight of water and the total dry weight of the other mixtures. After mixing evenly, the mixture is extruded and dried at 110°C for 4h, and then calcined at 550°C for 3h in an air atmosphere to obtain catalyst D-1.

[0110] Figure 2 TEM-EDX spectrum analysis diagram of the catalyst of comparative example 1, A is the TEM morphology diagram of the catalyst, B is the distribution diagram of aluminum elements, C is the distribution diagram of silicon elements, silicon elements only exist in molecular sieves, and molecular sieve grains can be determined, and D is the overlap diagram of silicon and aluminum elements of B and C. Figure 2 As can be seen from A, B and D, the catalyst molecular sieve of Comparative Example 1 has a clear boundary with the aluminum-based binder, and the Figure 2 As shown in the middle circle, it indicates that alumina clusters appear in the catalyst of Comparative Example 1.

[0111] Figure 3 is the MAS NMR of the catalyst of Comparative Example 1 27 Spectrum, as can be seen from the figure, catalyst D-1 has characteristic peaks belonging to the γ-Al2O3 phase at chemical shifts of 9ppm and 70ppm, which also indicates that alumina forms aggregated clusters.

[0112] The reaction was carried out according to the alkylation reaction method and conditions of Example 1.

[0113] The alumina content and structural parameters of the catalysts prepared in the above examples and comparative examples are shown in Table 1, and the results of the alkylation reaction are shown in Table 2. In Table 2, C8 selectivity represents the average result within the cycle life.

[0114] Table 1

[0115]

[0116] Table 2

[0117] Catalyst No. Catalyst life (h) <![CDATA[C8 selectivity (%)]]> Example 1 C-1 56 85 Example 2 C-2 62 79 Example 3 C-3 50 70 Example 4 C-4 58 75 Example 5 C-5 20 70 Example 6 C-6 24 72 Example 7 C-1 12 77 Comparative Example 1 D-1 10 60

[0118] It can be seen from Table 2 above that the catalyst life and C8 selectivity of the alkylation process are significantly increased.

[0119] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. An alkylation method, characterized in that: The method comprises: under alkylation reaction conditions, subjecting olefin and alkylate to an alkylation reaction in the presence of a solid acid alkylation catalyst; The solid acid alkylation catalyst comprises a molecular sieve and an aluminum-based binder. Based on the total amount of the catalyst, in the catalyst, 10%≤w(Al2O3)≤40%, w(Al2O3) represents the mass fraction of Al2O3 in the catalyst measured by an XRF method, and the Al2O3 comprises aluminum oxide in the aluminum-based binder and aluminum oxide in the molecular sieve; the d value of the catalyst is ≤10nm, and the d value represents the thickness of the aluminum-based binder from the edge of the crystal surface of the molecular sieve grains in the catalyst to the outside measured by a TEM method.

2. The method according to claim 1, wherein: Based on the total amount of the catalyst, in the catalyst, 15%≤w(Al2O3)≤35%; Preferably, the d value of the catalyst is 0.01-5 nm, more preferably 0.01-1 nm; Preferably, the aluminum-based binder contains at least a portion of free aluminum oxide, and preferably, the catalyst does not contain free aluminum oxide clusters with a particle size exceeding 0.1 nm.

3. The method according to claim 1 or 2, wherein: The molecular sieve is an aluminosilicate molecular sieve, preferably at least one selected from A-type molecular sieve, Y-type molecular sieve, X-type molecular sieve, MOR-type molecular sieve and ZSM-5 molecular sieve, more preferably Y-type molecular sieve and / or MOR-type molecular sieve; 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%; Preferably, the specific surface area of ​​the catalyst is greater than 400 m 2 / g, more preferably 550-800m 2 / g; Preferably, the total acid amount of the catalyst is 1000-5000 μmmol / g, more preferably 2000-4000 μmmol / g; Preferably, the framework aluminum index of the catalyst is 33-37, more preferably 35-37.

4. The method according to any one of claims 1 to 3, wherein: The catalyst preparation method comprises the following steps: (1) subjecting a solid-liquid mixture containing a binder precursor solution and a molecular sieve to a hydrolysis reaction with water, and then performing solid-liquid separation to obtain a solid mixture; (2) mixing the solid mixture of step (1) with a peptizing agent, an auxiliary agent and water to form a solid acid alkylation catalyst after drying and calcining; The binder precursor is selected from at least one of organic alcohol aluminums.

5. The method according to claim 4, wherein: In step (1), the binder precursor is selected from an organic aluminum alcohol having a carbon number less than 15, preferably at least one of aluminum ethoxide, aluminum isopropoxide and aluminum sec-butoxide; Preferably, in step (1), the binder precursor solution is prepared by dissolving the binder precursor in an organic solvent under ultrasonic conditions; Preferably, in step (1), the organic solvent is selected from at least one of methanol, ethanol, isopropanol and sec-butanol; Preferably, in step (1), the amount of the binder precursor and the organic solvent is such that the mass fraction of the obtained binder precursor solution calculated as oxide is 5-50%, more preferably 10-20%; Preferably, in step (1), the ultrasonic conditions include: temperature of 15-70°C and time of 1-6h.

6. The method according to claim 4, wherein: In step (1), the molecular sieve is an aluminosilicate molecular sieve, preferably at least one selected from the group consisting of A-type molecular sieve, Y-type molecular sieve, X-type molecular sieve, MOR-type molecular sieve and ZSM-5 molecular sieve, more preferably Y-type molecular sieve and / or MOR-type molecular sieve; Preferably, in step (1), the mass ratio of the molecular sieve calculated on a dry basis to the binder precursor solution calculated on an oxide basis is 10:1-2:1, more preferably 6:1-4:

1.

7. The method according to claim 4, wherein: 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, preferably 50:1-25:1; Preferably, in step (1), the water is added dropwise to the solid-liquid mixture containing the binder precursor solution and the molecular sieve, and the dripping rate of the water is 0.1-5 drops / s based on the mass of the solid-liquid mixture containing the binder precursor solution and the molecular sieve; Preferably, in step (1), the hydrolysis reaction is carried out in the presence of an alkaline compound, and the alkaline compound is selected from at least one of aqueous ammonia, tetramethylammonium hydroxide, tetraethylammonium hydroxide and tetrapropylammonium hydroxide; Preferably, in step (1), the conditions of the hydrolysis reaction include: temperature of 40-85° C., reaction time of 0.5-20 h, and pH of 8-11.

8. The method according to claim 4, wherein: In step (2), the peptizing agent is selected from at least one of hydrochloric acid, nitric acid, oxalic acid, hydrofluoric acid, fluorosilicic acid and citric acid; Preferably, in step (2), the mass ratio of the solid mixture to the peptizing agent is 100-50:1; Preferably, in step (2), the auxiliary agent is selected from at least one of sesbania powder, methyl cellulose, polyether, polyvinyl alcohol, cyclodextrin and chitosan; Preferably, in step (2), the mass ratio of the solid mixture to the auxiliary agent is 100-50:

1.

9. The method according to claim 4, wherein: In step (2), the drying conditions include: drying temperature of 80-150° C., and drying time of 1-12 h; Preferably, in step (2), the calcination conditions include: a calcination temperature of 450-650° C. and a calcination time of 1-12 h.

10. The method according to any one of claims 1 to 9, wherein: The alkylate is selected from at least one of isobutane, benzene, toluene and ethylbenzene, preferably isobutane; Preferably, the olefin is selected from at least one of ethylene, propylene, butene and pentene, more preferably butene; Preferably, the molar ratio of the alkylate to the olefin is 1-1000:1, more preferably 20-1000:1; Preferably, the conditions of the alkylation reaction include: temperature of 30-200°C, pressure of 0.5-6MPa, mass space velocity of olefin feed of 0.01-10h -1 ; Further preferably, the conditions of the alkylation reaction include: temperature of 10-100°C, pressure of 2-5 MPa, mass space velocity of olefin feed of 0.1-1 h -1 ; Preferably, the alkylation method further comprises: subjecting the solid acid alkylation catalyst to a reduction treatment under a reducing atmosphere before the alkylation reaction; Preferably, the reducing atmosphere is selected from at least one of nitrogen and / or an inert gas; Preferably, the reduction treatment conditions include: reducing atmosphere flow rate of 5-500 mL / (g catalyst·min), pressure of 0-2 MPa, heating rate of 0.2-10° C. / min, temperature of 200-600° C., and time of 2-6 h.

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