Monolithic binder-free hierarchical pore mww molecular sieves, methods of making and use thereof

Abstract

The present invention relates to a monolithic binder-free hierarchical-pore MWW molecular sieve, wherein the molecular sieve has micropores and mesopores, the micropores are pores with a pore size of less than 2 nm, the mesopores are pores with a pore size of 2-50 nm, and the mesopores account for more than 65% of the total pore volume. The present invention also relates to the use of the monolithic binder-free hierarchical-pore MWW molecular sieve as a catalyst in the production of cumene and a method for catalytically producing cumene using the monolithic binder-free hierarchical-pore MWW molecular sieve.

Description

TECHNICAL FIELD

[0001] The present application relates to MWW molecular sieve, in particular to a MWW molecular sieve and a preparation method and application thereof. BACKGROUND

[0002] Cumene is an important organic chemical raw material for producing phenol and acetone. Cumene is mainly synthesized by alkylation of benzene with propylene. UOP and Mobil processes are two representative processes for producing cumene. The former uses β molecular sieve as catalyst, and the latter uses MWW molecular sieve as catalyst. The UOP process needs to be regenerated by hot benzene washing of the catalyst after a period of reaction, while the Mobil process does not need regeneration operation. In recent years, the promotion of the UOP process has thus been limited to a certain extent.

[0003] Generally, the synthesized zeolite catalyst is fine powder with particle size of several nanometers to several microns. Such fine powder must be formed into granular, strip-shaped or other different forms together with inorganic binder (clay, alumina, etc.) to meet the application requirements. The presence of the binder disperses and dilutes the active component, blocks the pore channels of the zeolite molecular sieve, hinders the use of active sites, affects the diffusion of reactant molecules, and objectively reduces the selectivity of the reaction. It is an interesting research focus to combine the zeolite powder into monolithic catalyst without binder. The monolithic catalyst refers to an integrated catalyst with many narrow and orderly arranged pore channels. Compared with the traditional granular catalyst, the monolithic catalyst can improve the efficiency of catalysis, improve the selectivity of the reaction, and also help to realize low energy consumption, low emission and safe process. If the monolithic binder-free molecular sieve catalyst can be applied to the alkylation reaction for preparing cumene, it will play a good promoting role in optimizing the entire process.

[0004] In the prior art, benzene and propylene are first subjected to alkylation reaction in an alkylation reactor, and the polysubstituted cumene generated by the alkylation reaction is separated by a rectification system, and then mixed with benzene and introduced into a single-bed alkylation reactor for transalkylation reaction. In the transalkylation reaction of benzene and polysubstituted cumene, the transalkylation reaction of polysubstituted cumene often produces more impurity n-propylbenzene, which can seriously reduce the quality of product cumene. In patent documents CN102464563A, CN102464564A and CN102464565A, the conversion rate of polysubstituted cumene is improved, the n-propylbenzene generated by transalkylation is reduced, the generation efficiency is improved, and the product quality is improved by process optimization, but two reactors are needed. Therefore, it is of great significance to continue to seek a simpler process and reactor for industrial production. SUMMARY

[0005] The present application provides a multi-level pore MWW molecular sieve which, when used as a catalyst for synthesizing cumene, can directly convert diisopropylbenzene, so that the reactor is simplified from two to one, the process flow is shortened, and equipment investment is reduced.

[0006] In a first aspect, the present application provides a monolithic binder-free multi-level pore MWW molecular sieve, wherein the molecular sieve has micropores and mesopores, the micropores are pores with a pore size of less than 2 nm, and the mesopores are pores with a pore size of 2-50 nm, and the mesopores account for more than 65% of the total pore volume.

[0007] In some embodiments, the mesopores include first mesopores, second mesopores and third mesopores, the pore size d1 of the first mesopores satisfies: 2.0 nm < d1 ≤ 5.0 nm, the pore size d2 of the second mesopores satisfies: 5.0 nm < d2 ≤ 20 nm, and the pore size d3 of the third mesopores satisfies: 20 nm < d3 < 50 nm.

[0008] In some embodiments, the molecular sieve has one or more of the following characteristics (a) to (h):

[0009] (a) the acid amount of the molecular sieve is 1-2 mmol / g, preferably 1-1.5 mmol / g;

[0010] (b) the specific surface area of the molecular sieve is 450-600 m 2 / g, preferably 450-550 m 2 / g;

[0011] (c) the average pore size of the molecular sieve is 3-5 nm, preferably 3.2-4.5 nm;

[0012] (d) the total pore volume of the molecular sieve is 0.25-0.75 cm 3 / g, preferably 0.30-0.70 cm 3 / g;

[0013] (e) the micropore volume of the molecular sieve is 0.25-0.45 cm 3 / g, preferably 0.28-0.42 cm 3 / g;

[0014] (f) the pore volume of the first mesopores accounts for 25%-40% of the total pore volume, the pore volume of the second mesopores accounts for 25%-40% of the total pore volume, and the pore volume of the third mesopores accounts for 15% or less of the total pore volume, preferably 7-12%;

[0015] (g) the molecular sieve exhibits a closed hysteresis loop at P / P0 = 0.4-0.99 on nitrogen adsorption-desorption curves, with an adsorption-desorption mass difference of 0-4 cm3 / g; preferably, the closed hysteresis loop has a starting point at P / P0 = 0.45-0.99, with an adsorption-desorption mass difference of 0-3.5 cm3 / g. 2 2 / g; preferably, the closed hysteresis loop has a starting point at P / P0 = 0.45-0.99, with an adsorption-desorption mass difference of 0-3.5 cm3 / g.

[0016] (h) the molecular sieve has an X-ray diffraction (XRD) pattern with characteristic peaks at 2 theta angles of 7.5°±1°, 9.5°±1°, 25.5°±1°, preferably at 2 theta angles of 7.5°±1°, 9.5°±1°, 22.0°±1°, 25.5°±1°, more preferably at 2 theta angles of 7.5°±0.5°, 9.5°±0.5°, 22.0°±0.5°, 25.5°±0.5°.

[0017] In a second aspect, the present application provides a method for preparing a monolithic binder-free hierarchical pore MWW molecular sieve, the method comprising the following steps:

[0018] (1) forming and drying a mixture comprising a first silicon source, a first aluminum source, and a second silicon source to obtain a precursor material containing amorphous silica and an aluminum source;

[0019] (2) mixing the precursor material obtained in step (1) with a second aluminum source, a template agent, an alkali source, and water, and then performing crystallization to obtain an intermediate crystalline material;

[0020] (3) calcining the intermediate crystalline material obtained in step (2).

[0021] In some embodiments, the molar ratio of the first silicon source and the second silicon source, calculated on the basis of SiO2, is 1:(0.08-0.5), preferably 1:(0.1-0.4), for example 1:0.1, 1:0.15, 1:0.20, 1:0.25, 1:0.30, 1:0.35, 1:0.38.

[0022] In some embodiments, the molar ratio of the second aluminum source and the first aluminum source, calculated on the basis of Al2O3, is 1:(0.3-1.5), for example 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.2, 1:1.3, 1:0.4, 1:1.5.

[0023] In some embodiments, the molar ratio of the second aluminum source and the first aluminum source, calculated on the basis of Al2O3, is 1:(0.3-1.0).

[0024] ​In some embodiments, the molar ratio of the first silicon source, as Si02, to the first aluminum source, as Al203, is 1:(0.01-0.08). In some embodiments, the molar ratio of the first silicon source, as Si02, to the first aluminum source, as Al203, is 1:(0.02-0.08), such as 1:0.02, 1:0.025, 1:0.03, 1:0.035, 1:0.04, 1:0.045, 1:0.05, 1:0.055, 1:0.06, 1:0.065, 1:0.07, 1:0.075, 1:0.08.

[0025] In some embodiments, the molar ratio of the first silicon source, as Si02, to the first aluminum source, as Al203, is 1:(0.02-0.06).

[0026] In some embodiments, the molar ratio of the second silicon source, as Si02, to the second aluminum source, as Al203, is 1:(0.001-0.3), such as 1:0.002, 1:0.005, 1:0.006, 1:0.008, 1:0.01, 1:0.02, 1:0.03, 1:0.04, 1:0.05, 1:0.08, 1:0.1, 1:0.15, 1:0.20, 1:0.25, 1:0.3, 1:0.35, 1:0.4.

[0027] In some embodiments, the molar ratio of the second silicon source, as Si02, to the second aluminum source, as Al203, is 1:(0.05-0.2).

[0028] In some embodiments, the molar ratio of the total silicon source, as Si02, to the second aluminum source, as Al203, is 1:(0.005-0.2); preferably 1:(0.01-0.1), such as 1:0.01, 1:0.015, 1:0.02, 1:0.025, 1:0.03, 1:0.035, 1:0.04, 1:0.045, 1:0.05, 1:0.065, 1:0.07, 1:0.08, 1:0.09, 1:0.1.

[0029] In some embodiments, the molar ratio of the total silicon source, as Si02, to the template agent is 1:(0.2-0.6), preferably 1:(0.2-0.5), such as 1:0.2, 1:0.3, 1:0.4, 1:0.5.

[0030] In some embodiments, the molar ratio of the total silicon source, as Si02, to the base source is 1:(0.04-0.2), such as 1:0.05, 1:0.08, 1:0.1, 1:0.15, 1:0.20.

[0031] In some embodiments, the total silicon source has a molar ratio of Si02 to water of 1 : (10-30), for example 1 : 10, 1 : 11, 1 : 12, 1 : 13, 1 : 14, 1 : 15, 1 : 16, 1 : 17, 1 : 18, 1 : 19, 1 : 20, 1 : 21, 1 : 22, 1 : 23, 1 : 24, 1 : 23, or 1 : 25.

[0032] In some embodiments, the drying temperature is 80-200 °C, for example 90 °C, 100 °C, 120 °C, 140 °C, 160 °C, or 180 °C, preferably 100-150 °C.

[0033] In some embodiments, the drying time is 2-24 h, preferably 3-10 h.

[0034] In some embodiments, the calcination temperature is 450-1000 °C, preferably 500-750 °C. In some embodiments, the calcination temperature is 500 °C, 550 °C, 600 °C, 650 °C, 700 °C, 720 °C, 750 °C, or 800 °C.

[0035] In some embodiments, the calcination time is 1-12 h, preferably 2-10 h.

[0036] In some embodiments, the crystallization temperature is 130-200 °C, preferably 140-190 °C, for example 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, or 190 °C.

[0037] In some embodiments, the crystallization time is 12-100 h, preferably 24-100 h. In some embodiments, the crystallization time is 24 hours, 28 hours, 32 hours, 26 hours, 40 hours, 44 hours, 48 hours, 52 hours, 58 hours, 62 hours, 66 hours, 70 hours, 74 hours, or 80 hours.

[0038] In some embodiments, the first silicon source comprises one or more of solid silicon dioxide, silica gel, fumed silica, or a silica aerosol.

[0039] In some embodiments, the first aluminum source comprises one or more of aluminum hydroxide, sodium aluminate, aluminum isopropoxide, aluminum nitrate, anhydrous aluminum trichloride, aluminum sulfate, kaolin, or montmorillonite clay.

[0040] In some embodiments, the second aluminum source comprises one or more of aluminum hydroxide, sodium aluminate, aluminum isopropoxide, aluminum nitrate, anhydrous aluminum trichloride, or aluminum sulfate.

[0041] In some embodiments, the second silicon source is a silica sol.

[0042] In some embodiments, the second silicon source is 10-50 wt% of silica sol; preferably 35-45 wt% of silica sol.

[0043] In some embodiments, the template agent comprises an organic amine template agent; preferably, the organic amine template agent comprises one or more of hexamethyleneimine, piperidine, homopiperazine, ethylenediamine, N,N,N-trimethyl-1-adamantylammonium hydroxide.

[0044] In some embodiments, the organic amine template agent comprises hexamethyleneimine.

[0045] In some embodiments, the base source comprises an alkali metal hydroxide; preferably, the base source is NaOH or KOH.

[0046] The shaping can be by mixing with a certain extrusion aid. The extrusion aid can be a conventional extrusion aid in the art. The extrusion aid can be one or more of pearl millet powder, methyl cellulose, ethyl cellulose, graphite, starch, polyvinyl alcohol and polyacrylamide. In some embodiments of the present application, the extrusion aid is pearl millet powder.

[0047] In a third aspect, the present application provides use of the monolithic binder-free hierarchical-pore MWW molecular sieve according to the first aspect of the present application or the monolithic binder-free hierarchical-pore MWW molecular sieve prepared by the preparation method according to the second aspect of the present application as a catalyst in production of cumene.

[0048] In some embodiments, the raw material for production of cumene contains poly-cumene.

[0049] In some embodiments, the raw material for production of cumene contains di-cumene.

[0050] In some embodiments, the raw material for production of cumene contains benzene, di-cumene and propylene.

[0051] In a fourth aspect, the present application provides a method for producing cumene, wherein benzene, di-cumene and propylene are used as raw materials, the raw materials are reacted with a catalyst to synthesize cumene, and the catalyst is the monolithic binder-free hierarchical-pore MWW molecular sieve according to the present application or the monolithic binder-free hierarchical-pore MWW molecular sieve prepared by the preparation method according to the present application.

[0052] In some embodiments, the molar ratio of benzene to propylene is (1-6): 1, and the molar ratio of benzene to di-cumene is (5-20): 1.

[0053] In some embodiments, the molar ratio of benzene to propylene is (1-4): 1, and the molar ratio of benzene to di-cumene is (5-15): 1.

[0054] In some embodiments, the reaction temperature of the reaction is 120-250°C, and the reaction pressure is 1-5 MPa. In some embodiments, the reaction temperature of the reaction is 135-200°C, and the reaction pressure is 1-3.5 MPa.

[0055] In some embodiments, the weight hourly space velocity of propylene is 1-10 h -1 , for example, 1 h -1 , 3 h -1 , 5 h -1 , 7 h -1 , or 9 h -1 .

[0056] In some embodiments, the weight hourly space velocity of propylene is 1-8 h -1 .

[0057] The monolithic binder-free hierarchical MWW molecular sieve provided by the present application has micropores and mesopores, and the mesopores account for more than 65% of the total pore volume. When used for producing cumene from benzene, diisopropylbenzene and propylene, the specific pore structure is suitable for the alkylation reaction of benzene, diisopropylbenzene and propylene, and the molecular sieve has the characteristics of high activity, good selectivity, less by-products and simple process.

[0058] The preparation method of the present application utilizes the weak guiding ability of small-molecule organic amine template in the crystallization process of the molecular sieve, so that the precursor mixed with amorphous silica material and aluminum source material is in-situ converted into the monolithic binder-free MWW molecular sieve. Due to the interface shrinkage effect in the crystallization process, many regularly arranged mesopores are generated. The monolithic binder-free MWW molecular sieve provided by the present application has not only regular mesopore structure, but also two sets of micropore structure and lamellar morphology specific to MWW molecular sieve. When the molecular sieve is applied to the catalytic alkylation reaction of benzene, diisopropylbenzene and propylene, the molecular sieve has the advantages of good catalytic activity, faster material diffusion speed and more stable catalyst performance.

[0059] By using the hierarchical MWW molecular sieve provided by the present application, the conversion rate of polyisopropylbenzene is greatly improved without the need of two reactors to separate polyisopropylbenzene. BRIEF DESCRIPTION OF DRAWINGS

[0060] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, and together with the specific embodiments below, serve to explain the present application, but do not constitute a limitation on the present application.

[0061] Figure 1 The XRD spectrum of the monolithic binder-free MWW molecular sieve prepared for Example 1 of the present application.

[0062] Figure 2XRD pattern of the MWW molecular sieve synthesized by the conventional method of Invention Comparative Example 1 and binder molding.

[0063] Figure 3 N2adsorption-desorption curve of the monolithic binder-free MWW molecular sieve prepared in Invention Example 1. DETAILED DESCRIPTION

[0064] In order to make the objectives, technical solutions, and advantages of the present application clearer, the present application will be described in further detail below with reference to the embodiments and drawings. The specific embodiments described herein are merely intended to explain the present application and should not be used to constitute any limitation to the present application. In addition, in the following description, the description of well-known structures and techniques is omitted to avoid unnecessary confusion of the concepts of the present disclosure. Such structures and techniques are also described in many publications.

[0065] The endpoints of the ranges and any values described herein are not limited to the precise values stated. The ranges and values should be construed to be approximations that allow for significant variation. Various ranges of values that end with "X" are intended to mean from the lower value or limit of the range or the same until a value just less than or equal to X, even if this results in a range of values less than 1. For numerical ranges that include values ending in "X" there are no values that are meant to be excluded from the range, even if the 3 3 The reaction space velocity refers to the amount of gas treated per unit time per unit volume of catalyst under specified conditions, and the unit is m -1 .

[0066] The X-ray diffraction instrument used for the crystalline phase analysis of the molecular sieve was a Rigaku-Ultima type from Japan. The XRD test conditions were as follows: CuKα radiation, wavelength λ = 0.15432 nm; X-ray diffraction pattern scanning range 2θ = 5°-50°, scanning speed 10° / min, working voltage 40 kV, current 40 mA.

[0067] The N2physical adsorption was used to determine the average pore size and total pore volume of the molecular sieve. The test method was as follows: the specific surface area (BET) and pore volume of the sample were analyzed by using an Autosorb-I type automatic adsorption specific surface and porosity analyzer from Quantachrome Corporation of the United States, in which the cold trap was liquid nitrogen and the adsorption medium was high-purity nitrogen; the low-pressure section of the adsorption isotherm was analyzed by using the adsorption isotherm equation of the HK model to obtain the pore size distribution curve of the molecular sieve; the specific surface area and pore volume of the molecular sieve were calculated by the BET method and the t-plot method, respectively.

[0068] ​The product is analyzed by gas chromatography. A certain amount of the reaction mixture after reaction is injected into the gas chromatograph, and the chromatographic column is detected by FID after flowing through the column, and the external standard method is used for quantitative analysis. The gas chromatograph used is a 7890 type gas chromatograph produced by Agilent Company, and the analysis chromatographic column used is an INNOWAX column.

[0069] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0070] The term "wt%" means mass percentage.

[0071] In the following content, whether the words such as "about" or "approximately" are used or not, all the numbers disclosed herein are approximate values. The value of each number can be different by 1%, 2%, 5%, 7%, 8%, 10%, 15% or 20%. Whenever a number with N value is disclosed, any number with N+ / -1%, N+ / -2%, N+ / -3%, N+ / -5%, N+ / -7%, N+ / -8%, N+ / -10%, N+ / -15% or N+ / -20% value will be explicitly disclosed, wherein "+ / -" means plus or minus.

[0072] The calculation formula of conversion rate and selectivity in the application example is as follows:

[0073] Selectivity of cumene or triisopropylbenzene S IPB / DIPB = mass percentage of cumene or triisopropylbenzene / (mass percentage of each product and by-product in chromatogram) x 100%.

[0074] Conversion rate of benzene or propylene X BEN / PE = (initial concentration of benzene or propylene - final concentration of benzene or propylene) / (initial concentration of benzene or propylene) x 100%.

[0075] Conversion rate of diisopropylbenzene X DIPB = (moles of diisopropylbenzene at the outlet of the alkylation reactor per unit time - moles of diisopropylbenzene at the inlet of the alkylation reactor per unit time) / (moles of diisopropylbenzene at the inlet of the alkylation reactor per unit time) x 100%.

[0076] The application example of the determination method of the acid amount of the molecular sieve is as follows:

[0077] 0.5 g of the molecular sieve powder is weighed, 100 ml of water is added, and stirred for 10 minutes, 0.2 g of piperidine is added, and stirred for 30 minutes, 2 drops of phenolphthalein are added, and then the prepared 0.2 mol / l hydrogen potassium phthalate aqueous solution is titrated dropwise until the color of the phenolphthalein changes. The volume of the hydrogen potassium phthalate aqueous solution used for titration is calculated, and the acid amount of the molecular sieve is calculated in units of mmol / g. The calculation formula is as follows:

[0078] Molecular sieve acid amount = (weight of piperidine / 85.15 - concentration of hydrogen potassium phthalate x volume of hydrogen potassium phthalate / 1000) / weight of molecular sieve x 1000.

[0079] Examples

[0080] Examples 1-10 are prepared by the following method:

[0081] 1) The first silicon source and the first aluminum source are mixed, an appropriate amount of a extrusion aid (the extrusion aid can be one or more of pearl millet powder, methyl cellulose, ethyl cellulose, graphite, starch, polyvinyl alcohol and polyacrylamide. In some embodiments of the application, the extrusion aid used is pearl millet powder) is added with the second silicon source, and is formed into a strip with a diameter of 1 mm and a length of 0.5 cm. The above formed strip is dried at a certain temperature for a certain time to obtain a precursor silicon material.

[0082] 2) A certain mass of the second aluminum source, a template agent, an alkali source and H2O are dissolved and mixed; the precursor silicon material is added to the mixture. The mixture is crystallized at a certain temperature for a certain time to obtain an intermediate crystalline material. The intermediate crystalline material is taken out of the liquid, washed with deionized water, dried, and calcined in a muffle furnace at a certain temperature for a certain time to obtain a monolithic binder-free MWW molecular sieve.

[0083] The reaction conditions of each example are shown in Table 1, and the reaction materials and amounts are shown in Table 2:

[0084] Table 1: Reaction conditions

[0085]

[0086]

[0087] Table 2: Reaction materials

[0088]

[0089]

[0090] Table 2 continued

[0091]

[0092] The parameter test results of Example 1-10 are as follows:

[0093] Example 1: The XRD characterization results of the molecular sieve are as shown in Figure 1 The N2physical adsorption characterization results are as shown in Figure 3 It can be seen from Figure 1 that the molecular sieve is a typical MWW molecular sieve. From Figure 3 the hysteresis loop is observed, it can be determined that there are mesopores, the pore volume of the pores with a pore size less than 2.0 nm accounts for 26% of the total pore volume, the pore volume of the pores with a pore size of 2.0-5.0 nm accounts for 34% of the total pore volume, the pore volume of the pores with a pore size of 5.0-20.0 nm accounts for 32% of the total pore volume, and the pore volume of the pores with a pore size greater than 20.0 nm to 50.0 nm accounts for 8% of the total pore volume. The average pore diameter of the pores is 3.7 nm, the total pore volume is 0.51 cm 3 / g, the micropore volume is 0.31 cm 3 / g, and the specific surface area is 485 m 2 / g. The acid amount of the molecular sieve is 1.20 mmol / g.

[0094] Example 2: The N2physical adsorption characterization results of the molecular sieve are as follows: The hysteresis loop is observed, it can be determined that there are mesopores, the pore volume of the pores with a pore size less than 2.0 nm accounts for 30% of the total pore volume, the pore volume of the pores with a pore size of 2.0-5.0 nm accounts for 29% of the total pore volume, the pore volume of the pores with a pore size of 5.0-20.0 nm accounts for 31% of the total pore volume, and the pore volume of the pores with a pore size greater than 20.0 nm to 50.0 nm accounts for 10% of the total pore volume. The average pore diameter of the pores is 4.1 nm, the total pore volume is 0.53 cm 3 / g, the micropore volume is 0.37 cm 3 / g, and the specific surface area is 482 m 2 / g. The acid amount of the molecular sieve is 1.34 mmol / g.

[0095] Example 3: The N2physical adsorption characterization results of the molecular sieve are as follows: The hysteresis loop is observed, it can be determined that there are mesopores, the pore volume of the pores with a pore size less than 2.0 nm accounts for 21% of the total pore volume, the pore volume of the pores with a pore size of 2.0-5.0 nm accounts for 35% of the total pore volume, the pore volume of the pores with a pore size of 5.0-20.0 nm accounts for 37% of the total pore volume, and the pore volume of the pores with a pore size greater than 20.0 nm to 50.0 nm accounts for 7% of the total pore volume. The average pore diameter of the pores is 4.0 nm, the total pore volume is 0.60 cm 3 / g, the micropore volume is 0.41 cm 3 / g, and the specific surface area is 510 m 2 / g. The acid amount of the molecular sieve is 1.12 mmol / g.

[0096] Example 4: N2physical adsorption characterization results of the molecular sieve Hysteresis loop was observed, which indicated the existence of mesopores. The pore volume of pores with pore size less than 2.0 nm accounted for 29% of the total pore volume, the pore volume of pores with pore size of 2.0-5.0 nm accounted for 30% of the total pore volume, the pore volume of pores with pore size of 5.0-20.0 nm accounted for 33% of the total pore volume, and the pore volume of pores with pore size greater than 20.0 nm to 50.0 nm accounted for 8% of the total pore volume. The average pore diameter was 3.5 nm, the total pore volume was 0.38 cm3 / g, the micropore volume was 0.28 cm3 / g, and the specific surface area was 452 m2 / g. The acid amount of the molecular sieve was 1.45 mmol / g. 3 3 2 Example 4: N2physical adsorption characterization results of the molecular sieve Hysteresis loop was observed, which indicated the existence of mesopores. The pore volume of pores with pore size less than 2.0 nm accounted for 29% of the total pore volume, the pore volume of pores with pore size of 2.0-5.0 nm accounted for 30% of the total pore volume, the pore volume of pores with pore size of 5.0-20.0 nm accounted for 33% of the total pore volume, and the pore volume of pores with pore size greater than 20.0 nm to 50.0 nm accounted for 8% of the total pore volume. The average pore diameter was 3.5 nm, the total pore volume was 0.38 cm3 / g, the micropore volume was 0.28 cm3 / g, and the specific surface area was 452 m2 / g. The acid amount of the molecular sieve was 1.45 mmol / g.

[0097] Example 5: N2physical adsorption characterization results of the molecular sieve Hysteresis loop was observed, which indicated the existence of mesopores. The pore volume of pores with pore size less than 2.0 nm accounted for 35% of the total pore volume, the pore volume of pores with pore size of 2.0-5.0 nm accounted for 27% of the total pore volume, the pore volume of pores with pore size of 5.0-20.0 nm accounted for 29% of the total pore volume, and the pore volume of pores with pore size greater than 20.0 nm to 50.0 nm accounted for 9% of the total pore volume. The average pore diameter was 3.7 nm, the total pore volume was 0.40 cm3 / g, the micropore volume was 0.29 cm3 / g, and the specific surface area was 467 m2 / g. The acid amount of the molecular sieve was 1.37 mmol / g. 3 3 2 Example 5: N2physical adsorption characterization results of the molecular sieve Hysteresis loop was observed, which indicated the existence of mesopores. The pore volume of pores with pore size less than 2.0 nm accounted for 35% of the total pore volume, the pore volume of pores with pore size of 2.0-5.0 nm accounted for 27% of the total pore volume, the pore volume of pores with pore size of 5.0-20.0 nm accounted for 29% of the total pore volume, and the pore volume of pores with pore size greater than 20.0 nm to 50.0 nm accounted for 9% of the total pore volume. The average pore diameter was 3.7 nm, the total pore volume was 0.40 cm3 / g, the micropore volume was 0.29 cm3 / g, and the specific surface area was 467 m2 / g. The acid amount of the molecular sieve was 1.37 mmol / g.

[0098] Example 6: N2physical adsorption characterization results of the molecular sieve Hysteresis loop was observed, which indicated the existence of mesopores. The pore volume of pores with pore size less than 2.0 nm accounted for 31% of the total pore volume, the pore volume of pores with pore size of 2.0-5.0 nm accounted for 32% of the total pore volume, the pore volume of pores with pore size of 5.0-20.0 nm accounted for 25% of the total pore volume, and the pore volume of pores with pore size greater than 20.0 nm to 50.0 nm accounted for 12% of the total pore volume. The average pore diameter was 3.6 nm, the total pore volume was 0.55 cm3 / g, the micropore volume was 0.32 cm3 / g, and the specific surface area was 503 m2 / g. The acid amount of the molecular sieve was 1.31 mmol / g. 3 3 2 Example 6: N2physical adsorption characterization results of the molecular sieve Hysteresis loop was observed, which indicated the existence of mesopores. The pore volume of pores with pore size less than 2.0 nm accounted for 31% of the total pore volume, the pore volume of pores with pore size of 2.0-5.0 nm accounted for 32% of the total pore volume, the pore volume of pores with pore size of 5.0-20.0 nm accounted for 25% of the total pore volume, and the pore volume of pores with pore size greater than 20.0 nm to 50.0 nm accounted for 12% of the total pore volume. The average pore diameter was 3.6 nm, the total pore volume was 0.55 cm3 / g, the micropore volume was 0.32 cm3 / g, and the specific surface area was 503 m2 / g. The acid amount of the molecular sieve was 1.31 mmol / g.

[0099] ​​​​​​Example 7: The N2 physisorption characterization results of the molecular sieve showed a hysteresis loop, confirming the presence of mesopores. The measured pore volume was as follows: pores smaller than 2.0 nm accounted for 24% of the total pore volume; pores with a diameter of 2.0–5.0 nm accounted for 37%; pores with a diameter of 5.0–20.0 nm accounted for 29%; and pores with a diameter greater than 20.0 nm to 50.0 nm accounted for 10%. The average pore diameter was 3.8 nm, and the total pore volume was 0.54 cm³. 3 / g, micropore volume is 0.42cm³ 3 / g, specific surface area is 520m² 2 / g. The acidity of the molecular sieve is 1.42 mmol / g.

[0100] Example 8: The N2 physisorption characterization results of the molecular sieve showed a hysteresis loop, confirming the presence of mesopores. The measured pore volume was as follows: pores smaller than 2.0 nm accounted for 28% of the total pore volume; pores with a diameter of 2.0–5.0 nm accounted for 31%; pores with a diameter of 5.0–20.0 nm accounted for 32%; and pores with a diameter greater than 20.0 nm to 50.0 nm accounted for 9%. The average pore diameter was 3.9 nm, and the total pore volume was 0.62 cm³. 3 / g, micropore volume is 0.35cm³ 3 / g, specific surface area is 550m² 2 / g. The acidity of the molecular sieve is 1.28 mmol / g.

[0101] Example 9: The N2 physisorption characterization results of the molecular sieve showed a hysteresis loop, confirming the presence of mesopores. The measured pore volume was as follows: pores smaller than 2.0 nm accounted for 34% of the total pore volume; pores with a diameter of 2.0–5.0 nm accounted for 26%; pores with a diameter of 5.0–20.0 nm accounted for 30%; and pores with a diameter greater than 20.0 nm to 50.0 nm accounted for 10%. The average pore diameter was 3.8 nm, and the total pore volume was 0.47 cm³. 3 / g, micropore volume is 0.33cm³ 3 / g, specific surface area is 497m² 2 / g. The acidity of the molecular sieve is 1.50 mmol / g.

[0102] Example 10: The N2 physisorption characterization results of the molecular sieve showed a hysteresis loop, confirming the presence of mesopores. The measured pore volume was as follows: pores smaller than 2.0 nm accounted for 23% of the total pore volume; pores with a diameter of 2.0–5.0 nm accounted for 30%; pores with a diameter of 5.0–20.0 nm accounted for 36%; and pores with a diameter greater than 20.0 nm to 50.0 nm accounted for 11%. The average pore diameter was 4.2 nm, and the total pore volume was 0.59 cm³. 3 / g, micropore volume is 0.39cm³ 3 / g, specific surface area is 526m² 2 / g. The acidity of the molecular sieve is 1.03 mmol / g.

[0103] Application methods

[0104] One g of the prepared monolithic binder-free MWW molecular sieve was packed into a fixed-bed reactor, and a mixture of benzene, diisopropylbenzene, and propylene was introduced. The reaction was carried out at a temperature of 140°C, a pressure of 2.5 MPa, and a propylene space velocity of 1.5 h⁻¹. -1 The molar ratio of benzene to propylene was 2.0:1, and the molar ratio of benzene to diisopropylbenzene was 10.0:1. The reaction results of Examples 1-10 are shown in Table 3.

[0105] Table 3: Reaction Results of Examples

[0106]

[0107]

[0108] Examples 1A-1F

[0109] Except for the molar ratio of the first silicon source (calculated as SiO2) and the first and second aluminum sources (calculated as Al2O3) which differs from Example 1 (see Table 4 below for details), the same reaction conditions and reactants as in Example 1 were used.

[0110] Parameter test results:

[0111] Example 1A: No hysteresis loop was observed. The measured pore volume was as follows: pores with a diameter less than 2.0 nm accounted for 36% of the total pore volume; pores with a diameter between 2.0 and 5.0 nm accounted for 32%; pores with a diameter between 5.0 and 20.0 nm accounted for 23%; and pores with a diameter greater than 20.0 nm to 50.0 nm accounted for 9%. The average channel diameter was 3.1 nm, and the total pore volume was 0.36 cm³. 3 / g, micropore volume is 0.24cm³ 3 / g, specific surface area is 402m² 2 / g. The acidity of the molecular sieve is 0.98 mmol / g.

[0112] Example 1B: No hysteresis loop was observed, the volume of pores having a pore diameter less than 2.0 nm was measured to be 21% of the total pore volume, the volume of pores having a pore diameter in the range of 2.0 to 5.0 nm was measured to be 35% of the total pore volume, the volume of pores having a pore diameter in the range of 5.0 to 20.0 nm was measured to be 41% of the total pore volume, and the volume of pores having a pore diameter greater than 20.0 nm to 50.0 nm was measured to be 4% of the total pore volume. The average pore diameter was 3.3 nm, and the total pore volume was 0.30 cm3 / g. The micropore volume was 0.26 cm3 / g. The BET surface area was 421 m2 / g. The acid capacity of the molecular sieve was 0.97 millimoles of acid per gram. 3 3 The BET surface area was 433 m2 / g. The acid capacity of the molecular sieve was 1.02 millimoles of acid per gram. 2

[0113] Example 1C: No hysteresis loop was observed, the volume of pores having a pore diameter less than 2.0 nm was measured to be 26% of the total pore volume, the volume of pores having a pore diameter in the range of 2.0 to 5.0 nm was measured to be 27% of the total pore volume, the volume of pores having a pore diameter in the range of 5.0 to 20.0 nm was measured to be 42% of the total pore volume, and the volume of pores having a pore diameter greater than 20.0 nm to 50.0 nm was measured to be 5% of the total pore volume. The average pore diameter was 3.1 nm, and the total pore volume was 0.33 cm3 / g. The micropore volume was 0.24 cm3 / g. The BET surface area was 433 m2 / g. The acid capacity of the molecular sieve was 1.02 millimoles of acid per gram. 3 3 The BET surface area was 433 m2 / g. The acid capacity of the molecular sieve was 1.02 millimoles of acid per gram. 2

[0114] Example 1D: No hysteresis loop was observed, the volume of pores having a pore diameter less than 2.0 nm was measured to be 23% of the total pore volume, the volume of pores having a pore diameter in the range of 2.0 to 5.0 nm was measured to be 32% of the total pore volume, the volume of pores having a pore diameter in the range of 5.0 to 20.0 nm was measured to be 30% of the total pore volume, and the volume of pores having a pore diameter greater than 20.0 nm to 50.0 nm was measured to be 15% of the total pore volume. The average pore diameter was 2.7 nm, and the total pore volume was 0.31 cm3 / g. The micropore volume was 0.22 cm3 / g. The BET surface area was 380 m2 / g. The acid capacity of the molecular sieve was 0.99 millimoles of acid per gram. 3 3 The BET surface area was 433 m2 / g. The acid capacity of the molecular sieve was 1.02 millimoles of acid per gram. 2

[0115] Example 1E: No hysteresis loop was observed, the volume of pores having a pore diameter less than 2.0 nm was measured to be 26% of the total pore volume, the volume of pores having a pore diameter in the range of 2.0 to 5.0 nm was measured to be 34% of the total pore volume, the volume of pores having a pore diameter in the range of 5.0 to 20.0 nm was measured to be 24% of the total pore volume, and the volume of pores having a pore diameter greater than 20.0 nm to 50.0 nm was measured to be 16% of the total pore volume. The average pore diameter was 4.3 nm, and the total pore volume was 0.65 cm3 / g. The micropore volume was 0.21 cm3 / g. The BET surface area was 440 m2 / g. The acid capacity of the molecular sieve was 0.97 millimoles of acid per gram. 3 3 The BET surface area was 433 m2 / g. The acid capacity of the molecular sieve was 1.02 millimoles of acid per gram. 2 ​​​​​​​ / g. The acid amount of the molecular sieve was 0.89 mmol / g.

[0116] Example 1F: No hysteresis loop was observed. The volume of the pores with a pore diameter less than 2.0 nm was 19% of the total pore volume, the volume of the pores with a pore diameter between 2.0 and 5.0 nm was 36% of the total pore volume, the volume of the pores with a pore diameter between 5.0 and 20.0 nm was 36% of the total pore volume, and the volume of the pores with a pore diameter greater than 20.0 nm to 50.0 nm was 9% of the total pore volume. The average pore diameter was 3.4 nm, and the total pore volume was 0.36 cm 3 / g. The micropore volume was 0.24 cm 3 / g. The specific surface area was 412 m 2 / g. The acid amount of the molecular sieve was 0.95 mmol / g.

[0117] Reaction results: The same application method as in Example 1 was used. The reaction results are shown in Table 4:

[0118] Table 4: Reaction results

[0119]

[0120] Comparative Example

[0121] Comparative Example 1

[0122] A mixture of 40% silica sol 28.94 g, aluminum sulfate 1.65 g, hexamethyleneimine 3.81 g, NaOH 0.77 g and H2O 51.98 g was dissolved and mixed, and the molar ratio of SiO2, Al2O3, hexamethyleneimine, NaOH and water in the mixture was 1:0.025:0.2:0.10:15. The mixture was crystallized at a temperature of 180°C for 48 hours to obtain a raw powder of the molecular sieve. The raw powder was suction filtered, washed with deionized water and dried. The obtained powder was shaped into a strip with a diameter of 1 mm and a length of 0.5 cm using pseudoboehmite and 5% dilute nitric acid, and an appropriate amount of a binder. The mass ratio of the raw powder and the aluminum oxide was 6.5:3.5. The shaped strip was dried at 120°C for 3 hours. The dried strip was calcined in a muffle furnace at 550°C for 5 hours to obtain a MWW molecular sieve synthesized by a conventional method and shaped using a binder.

[0123] Parameter test results:

[0124] The XRD characterization results of the above molecular sieve are shown in Figure 2 From Figure 2 it can be seen that the molecular sieve is a typical MWW molecular sieve. Using the same test method as in Example 1 above, no hysteresis loop was observed. The average pore diameter of the molecular sieve was 2.0 nm, and the total pore volume was 0.15 cm 3 g -1 , and the micropore volume was 0.10 cm3 g -1 The volume of the pores with a pore diameter less than 2.0 nm accounts for 51% of the total pore volume, the volume of the pores with a pore diameter of 2.0-5.0 nm accounts for 35% of the total pore volume, the volume of the pores with a pore diameter of 5.0-20.0 nm accounts for 10% of the total pore volume, and the volume of the pores with a pore diameter greater than 20.0 nm to 50.0 nm accounts for less than 5% of the total pore volume. The specific surface area of the MWW molecular sieve is measured to be 279 cm 2 / g. The acid amount of the molecular sieve is 1.15 mmol / g.

[0125] Reaction results:

[0126] The same application method as in Example 1 is used. The conversion rate of propylene is 100%, the selectivity of cumene is 82.5%, the conversion rate of diisopropylbenzene is 3.2%, and the selectivity of triisopropylbenzene is 1.86%.

[0127] The above describes the preferred embodiments of the present application in detail, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as the disclosed content of the present application and fall within the protection scope of the present application.

Claims

1. A monolithic binder-free hierarchical pore MWW molecular sieve, wherein, The molecular sieve has micropores and mesopores, the micropores are pores with a pore size of less than 2 nm, and the mesopores are pores with a pore size of 2-50 nm, and the mesopores account for more than 65% of the total pore volume; The mesopores include first mesopores, second mesopores and third mesopores, the first mesopores have a pore size d1 satisfying 2.0 nm < d1 ≤ 5.0 nm, the second mesopores have a pore size d2 satisfying 5.0 nm < d2 ≤ 20 nm, and the third mesopores have a pore size d3 satisfying 20 nm < d3 < 50 nm; The average pore size of the molecular sieve is 3-5 nm; the total pore volume of the molecular sieve is 0.25-0.75 cm 3 / g; the micropore volume of the molecular sieve is 0.25-0.45 cm 3 / g; the pore volume of the first mesopore accounts for 25%-40% of the total pore volume, the pore volume of the second mesopore accounts for 25%-40% of the total pore volume, and the pore volume of the third mesopore accounts for 15% or less of the total pore volume. The molecular sieve has a closed hysteresis loop at a nitrogen adsorption-desorption curve P / P0=0.4-0.99, and an adsorption curve-absorbed mass difference with a desorption curve is 0-4 cm 2 / g.

2. The MWW molecular sieve of claim 1, characterized by, The molecular sieve has one or more of the following characteristics (a) to (h): (a) The acid amount of the molecular sieve is 1-2 mmol / g; (b) the molecular sieve has a specific surface area in the range of 450 to 600 m 2 / g; (c) The average pore size of the molecular sieve is 3.2-4.5 nm; (d) the total pore volume of the molecular sieve is 0.30 to 0.70 cm3 / g; 3 / g; (e) the micropore volume of the molecular sieve is 0.28 to 0.42 cm3 / g 3 / g; (f) The pore volume of the first mesopores accounts for 25%-40% of the total pore volume, the pore volume of the second mesopores accounts for 25%-40% of the total pore volume, and the pore volume of the third mesopores accounts for 7-12% of the total pore volume; (g) the starting position of the closure hysteresis loop is at P / P0 = 0.45-0.99, the difference in adsorption and desorption curves in terms of mass absorbed is 0-3.5 cm 2 / g; (h) The X-ray diffraction (XRD) pattern of the molecular sieve has characteristic peaks at 2θ angles of 7.5°±1°, 9.5°±1° and 25.5°±1°.

3. The MWW molecular sieve of claim 1 or 2, characterized in that, The acid amount of the molecular sieve is 1-1.5 mmol / g.

4. The MWW molecular sieve of claim 1 or 2, characterized in that, The specific surface area of the molecular sieve is 450-550 m 2 / g.

5. The MWW molecular sieve of claim 1 or 2, wherein The X-ray diffraction (XRD) pattern of the molecular sieve has characteristic peaks at 2θ angles of 7.5°±1°, 9.5°±1°, 22.0°±1° and 25.5°±1°.

6. The MWW molecular sieve of claim 1 or 2, wherein The X-ray diffraction (XRD) pattern of the molecular sieve has characteristic peaks at 2θ angles of 7.5°±0.5°, 9.5°±0.5°, 22.0°±0.5° and 25.5°±0.5°.

7. A method for preparing a monolithic binderless hierarchical-pore MWW molecular sieve according to any one of claims 1-6, comprising the following steps: (1) forming and drying a mixture containing a first silicon source, a first aluminum source and a second silicon source to obtain a precursor material containing amorphous silicon dioxide and an aluminum source; (2) mixing the precursor material obtained in step (1) with a second aluminum source, a template agent, an alkali source and water, and then performing crystallization to obtain an intermediate crystalline material; (3) calcining the intermediate crystalline material obtained in step (2); the molar ratio of the first silicon source to the second silicon source, calculated based on SiO2, is 1:(0.1-0.4); the molar ratio of the second aluminum source to the first aluminum source, calculated based on Al2O3, is 1:(0.3-1.5); the molar ratio of the first silicon source, calculated based on SiO2, to the first aluminum source, calculated based on Al2O3, is 1:(0.02-0.0543); the molar ratio of the second silicon source, calculated based on SiO2, to the second aluminum source, calculated based on Al2O3, is 1:(0.072-0.3); the molar ratio of the total silicon source, calculated based on SiO2, to the second aluminum source, calculated based on Al2O3, is 1:(0.005-0.2); the molar ratio of the total silicon source, calculated based on SiO2, to the template agent is 1:(0.2-0.6); the molar ratio of the total silicon source, calculated based on SiO2, to the alkali source is 1:(0.04-0.2); the molar ratio of the total silicon source, calculated based on SiO2, to water is 1:(10-30); The crystallization temperature is 130-200℃, and the crystallization time is 12-100 hours. The second silicon source is silica sol, and the template agent comprises one or more of hexamethyleneimine, piperidine, homopiperazine, ethylenediamine, and N,N,N-trimethyl-1-adamantylammonium hydroxide.

8. The preparation method according to claim 7, characterized in that, The molar ratio of the second aluminum source to the first aluminum source, calculated as Al2O3, is 1:(0.3-1.0).

9. The preparation method according to claim 7, characterized in that, The molar ratio of the second silicon source, calculated as SiO2, to the second aluminum source, calculated as Al2O3, is 1:(0.072-0.2).

10. The preparation method according to claim 7, characterized in that, The molar ratio of the total silicon source, calculated as SiO2, to the second aluminum source, calculated as Al2O3, is 1:(0.01-0.1).

11. The preparation method according to claim 7, characterized in that, The drying temperature is 80-200℃; the drying time is 2-24h; and / or The calcination temperature is 450-1000℃; the calcination time is 1-12h; and / or The crystallization temperature is 140-190℃; and the crystallization time is 24-100h.

12. The method of claim 7, wherein, The drying temperature is 100-150℃.

13. The preparation method according to claim 7, characterized in that, The drying time is 3-10h.

14. The preparation method according to claim 7, characterized in that, The calcination temperature is 500-750℃.

15. The preparation method according to claim 7, characterized in that, The calcination time is 2-10h.

16. The preparation method according to claim 7, characterized in that, The first silicon source comprises one or more of solid silicon dioxide, silica gel, white carbon black, or silicon dioxide aerosol; and / or The first aluminum source comprises one or more of aluminum hydroxide, sodium aluminate, aluminum isopropoxide, aluminum nitrate, anhydrous aluminum trichloride, aluminum sulfate, kaolin, or montmorillonite; and / or The second aluminum source comprises one or more of aluminum hydroxide, sodium aluminate, aluminum isopropoxide, aluminum nitrate, anhydrous aluminum trichloride, or aluminum sulfate; and / or The second silicon source is 10-50wt% silica sol; and / or The template agent comprises hexamethyleneimine; and / or The alkali source comprises an alkali metal hydroxide.

17. The method of claim 7, wherein the method further comprises, The second silicon source is 35-45wt% silica sol.

18. The method of claim 7, wherein, The alkali source is NaOH or KOH.

19. Use of the monolithic binder-free hierarchical-pore MWW molecular sieve of any one of claims 1-6 or the monolithic binder-free hierarchical-pore MWW molecular sieve prepared by the preparation method of any one of claims 7-18 as a catalyst in the production of cumene.

20. Use according to claim 19, characterized in that, The raw material for the production of cumene contains poly-cumene.

21. The use according to claim 19, characterized in that, The raw material for the production of cumene contains di-cumene.

22. The use according to claim 19, characterized in that, The raw material for the production of cumene contains benzene, di-cumene, and propylene.

23. A process for the production of cumene wherein, The raw material for the production of cumene contains benzene, di-cumene, and propylene.

24. The method of claim 23, wherein, The molar ratio of benzene to propylene is (1-6):1, and the molar ratio of benzene to di-cumene is (5-20):

1.

25. The method of claim 23, wherein, The molar ratio of benzene to propylene is (1-4):1, and the molar ratio of benzene to di-cumene is (5-15):

1.

26. The method of claim 23 or 24, wherein, The reaction temperature of the reaction is 120-250°C, the reaction pressure is 1-5 MPa, the weight hourly space velocity of propylene is 1-10 h -1 .

27. The method of claim 23 or 24, wherein, The reaction temperature of the reaction is 135-200°C, the reaction pressure is 1-3.5 MPa, the weight hourly space velocity of propylene is 1-8 h -1 .

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