A coexistent molecular sieve containing mfi and a preparation method and application thereof

Abstract

The application discloses a kind of containing MFI symbiotic molecular sieve and its preparation method and application.The symbiotic molecular sieve has MFI molecular sieve, simultaneously still has at least one phase of MWW molecular sieve, FER molecular sieve, the symbiotic molecular sieve has as formula " mSiO2·nAl2O3·pSDA1·qSDA2 " shown schematic chemical composition, wherein 25≤m / n≤40,100≤m / p≤1000,0.1≤p / q≤1,SDA1 is N, N, N-trimethyladamantammonium, SDA2 is cyclohexylamine the symbiotic molecular sieve.The symbiotic molecular sieve can be used as adsorbent or organic compound conversion catalyst.

Description

Technical Field

[0001] This invention belongs to the field of molecular sieve synthesis technology, specifically relating to a symbiotic molecular sieve containing MFI, its preparation method, and its application. Background Technology

[0002] MFI molecular sieves have two sets of intersecting ten-membered ring channels. One type is a straight channel parallel to the b-axis with a pore size of approximately 0.54 nm × 0.56 nm. The other type is an elliptical channel (Z-type channel) parallel to the a-axis with a major axis pore size of approximately 0.57 nm × 0.58 nm and a minor axis pore size of approximately 0.51 nm × 0.52 nm. Typical materials include ZSM-5, Silicalite-1, and TS-1 molecular sieves. MWW-structured molecular sieves have two independent, non-interconnected ten-membered ring channel systems: one set of two-dimensional sinusoidal channels with an approximately elliptical cross-section and a pore size of 0.41 nm × 0.51 nm; the other set of ten-membered ring channels contains an approximately cylindrical twelve-membered ring supercage with dimensions of 0.71 nm × 0.71 nm × 1.82 nm, which is connected to the outside world through a slightly distorted ten-membered ring window (0.40 nm × 0.55 nm); typical MWW-type molecular sieves include MCM-22, MCM-49, ITQ-1, SSZ-25, ERB-1, and SCM-1. FER molecular sieve is a mesoporous molecular sieve with an interlaced two-dimensional channel structure consisting of eight-membered rings (0.48nm×0.35nm) parallel to the

[010] crystal plane and ten-membered rings (0.54nm×0.45nm) parallel to the

[001] crystal plane, as well as elliptical FER cages formed by the intersection of six-membered rings parallel to the ten-membered rings and eight-membered rings. The most common material is ZSM-35 molecular sieve.

[0003] Due to their excellent shape-selective catalytic performance and good thermal stability, the three types of molecular sieves mentioned above, especially MFI-type molecular sieves, are widely used in catalysis and adsorption in petrochemical industries. However, due to their uniform and singular pore size, weak acidity, low activity, and poor selectivity, they are difficult to use alone to treat complex components, and their catalytic performance differs for the same reactants. Porous symbiotic molecular sieves containing two or more components have a hierarchical pore structure and a wide distribution of strong and weak acids. They can treat complex components with varying molecular diameters and can leverage their respective advantages in catalytic reactions to synergistically treat complex components with different molecular sizes.

[0004] Patents CN1296275C and CN1296276C disclose the synthesis of mixed-crystal materials of β-zeolite and mordenite by using ZSM-5 or mordenite molecular sieves as seed crystals and adding them to the synthesis solutions of mordenite zeolite or β-zeolite, respectively. Patent CN101279743B discloses a symbiotic molecular sieve and its synthesis method. By adding seed crystals containing β-zeolite precursors during the synthesis of the symbiotic molecular sieve and controlling the nucleation and growth process of the molecular sieve, a symbiotic molecular sieve material of ZSM-5 / mordenite / β-zeolite is prepared. Patent CN100586858C discloses a porous symbiotic material and its synthesis method. By controlling the nucleation and growth process of the molecular sieve during the synthesis of the porous material, a porous symbiotic material with an adjustable symbiotic phase ratio is prepared. This ZSM-5 / mordenite / β-zeolite symbiotic molecular sieve material can be used in the industrial production of ethylene and propylene from naphtha catalytic cracking. Patent CN1242918C discloses the synthesis of a composite molecular sieve with both TON and MFI structures under static conditions. During the preparation process, a small amount of seed crystals and salts were added, and the crystallization parameters were controlled to obtain molecular sieves with different proportions of the two crystal forms. The resulting composite molecular sieve can be used in the reaction process of mixtures such as petroleum fractions. Patent CN104549408B discloses an in-situ co-existing methanol aromatization catalyst of MCM-22 / ZSM-5 and its preparation method. Using ZSM-5 as one of the raw materials, a core-shell-like molecular sieve of MCM-22 / ZSM-5 was synthesized. The two-phase molecular sieve is in a near-mechanically mixed state and can be used in the industrial production of methanol to aromatics. Patent CN102039162B discloses a binder-free ZSM-5 / β-zeolite co-existing molecular sieve catalyst and its preparation method. Also using ZSM-5 as one of the raw materials, the prepared two-phase molecular sieve is in a near-mechanically mixed state and has good application in the catalytic cracking of naphtha to propylene.

[0005] The aforementioned symbiotic zeolite molecular sieves are typically combinations of MFI and MOR molecular sieves, or MFI and β molecular sieves. Currently, there are no reports of directly synthesizing porous symbiotic molecular sieves from MFI and MWW type molecular sieves, or MFI and FER type molecular sieves. Preparing symbiotic molecular sieves containing both MFI and MWW type or FER type molecular sieves will help expand their application scenarios. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a symbiotic molecular sieve containing MFI, its preparation method and application.

[0007] The first aspect of the present invention provides a symbiotic molecular sieve containing MFI, wherein the symbiotic molecular sieve has MFI molecular sieve and at least one phase selected from MWW molecular sieve and FER molecular sieve, and the symbiotic molecular sieve has an illustrative chemical composition as shown in the formula "mSiO2·nAl2O3·pSDA1·qSDA2", wherein 25≤m / n≤40, 100≤m / p≤1000, 0.1≤p / q≤1, preferably, 25≤m / n≤40, 200≤m / p≤1000, 0.1≤p / q≤0.5; SDA1 is N,N,N-trimethyladamantaneammonium, and SDA2 is cyclohexylamine.

[0008] Furthermore, the symbiotic molecular sieve is an MFI / MWW symbiotic molecular sieve, an MFI / FER symbiotic molecular sieve, or an MFI / MWW / FER symbiotic molecular sieve.

[0009] Furthermore, the symbiotic molecular sieve includes an X-ray diffraction pattern as shown in Table a, and also has at least one X-ray diffraction pattern selected from Table b or Table c; wherein, Table a is the XRD pattern of MFI molecular sieve, Table b is the XRD pattern of MWW molecular sieve, and Table c is the XRD pattern of FER molecular sieve.

[0010] Table a

[0011]

[0012] Table b

[0013]

[0014] Table c

[0015]

[0016] a: ±0.30°, b: varies with 2θ.

[0017] Furthermore, in the symbiotic molecular sieve, MFI molecular sieve accounts for 40% to 95% of the mass of the symbiotic molecular sieve.

[0018] Furthermore, the symbiotic molecular sieve is an MFI / MWW / FER symbiotic molecular sieve, wherein the mass ratio of MWW molecular sieve to FER molecular sieve is 0.05 to 20, preferably 0.10 to 10.

[0019] A second aspect of the present invention provides a method for preparing a symbiotic molecular sieve containing MFI, comprising the following steps:

[0020] A silicon source, an aluminum source, sodium hydroxide, organic structure directing agent a, organic structure directing agent b, and water are mixed, and then the mixture is subjected to a one-step crystallization treatment to obtain the symbiotic molecular sieve.

[0021] The silicon source is calculated as SiO2, the aluminum source as Al2O3, sodium hydroxide, organic structure directing agent a (SDA1) as N,N,N-trimethyladamantane ammonium, organic structure directing agent b (SDA2) as cyclohexylamine, and water, in a molar ratio of SiO2:Al2O3:NaOH:SDA1:SDA2:H2O = 1:0.025~0.040:0.09~0.21:0.001~0.015:0.005~0.05:12~50.

[0022] Furthermore, the added silicon source (calculated as SiO2), aluminum source (calculated as Al2O3), sodium hydroxide, organic structure directing agent a (calculated as N,N,N-trimethyladamantane ammonium), organic structure directing agent b (calculated as cyclohexylamine), and water are in a molar ratio of SiO2:Al2O3:NaOH:SDA1:SDA2:H2O = 1:0.025~0.040:0.10~0.20:0.001~0.010:0.01~0.04:14~40.

[0023] Furthermore, the silicon source is silica sol; the aluminum source is sodium aluminate.

[0024] Furthermore, the crystallization conditions of the reaction mixture are crystallization at 155–175°C for 4.0–9.0 days, preferably at 160–170°C for 4.5–8.0 days.

[0025] Furthermore, the crystallization process of the reaction mixture is a dynamic crystallization by rotation or stirring, with a rotation or stirring speed of 10 to 60 rpm.

[0026] Furthermore, the yield of the symbiotic molecular sieve product exceeds 80%.

[0027] Furthermore, the crystallization can be carried out in any manner conventionally known in the art, such as by mixing the silicon source, aluminum source, sodium hydroxide, organic structure directing agent a, organic structure directing agent b and water in a predetermined ratio, and then heating the resulting mixture under crystallization conditions.

[0028] Furthermore, after the crystallization step, the obtained mixture can be processed to obtain the product by any conventionally known separation method. Examples of such separation methods include filtering, washing, and drying the obtained mixture. Here, the filtration, washing, and drying can be performed in any manner conventionally known in the art. Specifically, for example, the filtration can be performed by simply vacuum filtering the obtained product mixture. For example, washing can be performed using deionized water and / or ethanol. For example, the drying temperature can be 40–250°C, preferably 60–150°C, and the drying time can be 8–30 hours, preferably 10–20 hours. This drying can be carried out under normal pressure or under reduced pressure.

[0029] Furthermore, after the crystallization step, the resulting symbiotic molecular sieve can be further processed by calcination to obtain a sodium-type symbiotic molecular sieve. The calcination can be carried out in any manner conventionally known in the art, for example, the calcination temperature is generally 300–800°C, preferably 400–650°C, and the calcination time is generally 1–10 hours, preferably 3–6 hours. In addition, the calcination is generally carried out in an oxygen-containing atmosphere, such as air or an oxygen atmosphere.

[0030] Furthermore, the total specific surface area of ​​the sodium-type symbiotic molecular sieve is not less than 350 m². 2 / gram, preferably 350-550 meters 2 / gram; external specific surface area not less than 20 m² 2 / gram, preferably 20-120 meters 2 / gram; total pore volume not less than 0.30 cm³ 3 / gram, preferably 0.30 to 1.00 cm 3 / gram; micropore volume not less than 0.14 cm³ 3 / gram, preferably 0.14 to 0.20 cm 3 / gram.

[0031] Furthermore, the sodium-type symbiotic molecular sieve is subjected to ammonium ion exchange and calcination to obtain a hydrogen-type symbiotic molecular sieve.

[0032] Furthermore, the ammonium ion exchange is a conventional exchange method, specifically as follows: sodium-type symbiotic molecular sieves and ammonium salts are exchanged at a solid-liquid mass ratio of 1:5 to 1:20 at 30 to 80°C for 1 to 8 hours. The solid is then separated, and the exchange process is repeated 0 to 2 times. After filtration and washing, the filter cake is dried overnight in an oven at 40 to 110°C and then calcined at 450 to 650°C for 1 to 12 hours. The ammonium salt used in the exchange is selected from at least one of ammonium chloride, ammonium nitrate, ammonium carbonate, and ammonium sulfate; the concentration of ammonium ions in the ammonium salt solution is 0.1 to 1 mol / L.

[0033] Furthermore, the total acid content of the hydrogen-type symbiotic molecular sieve is not less than 600 μmol / g, preferably 600–1400 μmol / g; the strong acid content is not less than 200 μmol / g, preferably 200–600 μmol / g.

[0034] A third aspect of the present invention also provides a symbiotic molecular sieve composition containing MFI, comprising a symbiotic molecular sieve containing MFI prepared according to any of the methods described in the first aspect or according to any of the methods described in the second aspect, and a binder.

[0035] The fourth aspect of the present invention also provides the use of the MFI-containing symbiotic molecular sieve according to any of the first aspects described above, or the MFI-containing symbiotic molecular sieve prepared according to any of the preparation methods described in the second aspect described above, or the MFI-containing symbiotic molecular sieve composition according to the third aspect described above, as an adsorbent or a catalyst for the conversion of organic compounds.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] The symbiotic molecular sieve of the present invention is a novel symbiotic molecular sieve, specifically a symbiotic molecular sieve formed by MFI molecular sieve and at least one of MWW molecular sieve or FER molecular sieve.

[0038] This invention employs a technique that involves adding a small amount of dual-organic-structure directing agents (N,N,N-trimethyladamantane ammonium and cyclohexylamine) to a hydrothermal synthesis system, eliminating the need for seed crystals and temperature-dependent crystallization. By controlling the appropriate crystallization time, a symbiotic molecular sieve containing MFI is ultimately obtained. This method is simple and feasible, yielding a high yield of symbiotic molecular sieves with high acid content and a high concentration of strong acids. Attached Figure Description

[0039] Figure 1 The X-ray diffraction pattern of the sample in Example 1;

[0040] Figure 2 The X-ray diffraction pattern of the sample in Example 2;

[0041] Figure 3 The X-ray diffraction pattern of the sample in Example 3;

[0042] Figure 4 The X-ray diffraction pattern of the sample in Example 4;

[0043] Figure 5 The X-ray diffraction pattern of the sample in Example 5;

[0044] Figure 6 The X-ray diffraction pattern of the sample in Example 6;

[0045] Figure 7 The X-ray diffraction pattern of the sample in Example 7;

[0046] Figure 8 The X-ray diffraction pattern of the sample in Example 8;

[0047] Figure 9 The X-ray diffraction pattern of the sample in Example 9;

[0048] Figure 10 The X-ray diffraction pattern of the sample in Comparative Example 1 is shown.

[0049] Figure 11 The X-ray diffraction pattern of the sample in Comparative Example 2;

[0050] Figure 12 The image shows the X-ray diffraction pattern of the sample in Comparative Example 3. Detailed Implementation

[0051] According to the present invention, the aforementioned molecular sieves can be used in any physical form, such as powder, granules, or molded forms (e.g., strips, clover shapes, etc.). These physical forms can be obtained in any manner conventionally known in the art, without particular limitation.

[0052] In the context of this specification, the structure of the symbiotic molecular sieve containing MFI is determined by X-ray diffraction (XRD), which is determined by an X-ray powder diffractometer using a Cu-Kα ray source and a nickel filter.

[0053] In the context of this specification, in the XRD data of molecular sieves, w, m, s, and vs represent diffraction peak intensities, with w being weak, m being moderate, s being strong, and vs being very strong, as is well known to those skilled in the art. Generally, w is less than 20; m is 20–40; s is 40–70; and vs is greater than 70.

[0054] In the context of this specification, including in the following examples and comparative examples, the X-ray powder diffractometer used for the molecular sieves is a Panalytical X-PERPRO type X-ray powder diffractometer, used to analyze the phase composition of the samples, and a CuKα ray source. Nickel filter, 2θ scanning range 2~50°, operating voltage 40KV, current 40mA, scanning rate 10° / min.

[0055] In the context of this specification, including in the following examples and comparative examples, the micropore size, pore volume, specific surface area, and external specific surface area of ​​the molecular sieve were measured by the nitrogen physical adsorption-desorption method (BET method): the nitrogen physical adsorption-desorption isotherm of the molecular sieve was measured using a Micromeretic ASAP2020M physical adsorption instrument, and then calculated using the BET equation and t-plot equation. The experimental conditions for this molecular sieve were: measurement temperature -196℃, and before measurement, the molecular sieve was heat-treated at 550℃ in air for 6 hours, followed by pretreatment in vacuum at 350℃ for 4 hours.

[0056] In the context of this specification, including in the following examples and comparative examples, the content of each element in the molecular sieve was determined using an inductively coupled plasma atomic emission spectrometer (ICP), model Varian 725-ES. The analytical sample was dissolved in hydrofluoric acid before testing, and the content was expressed in moles.

[0057] In the context of this specification, including the following examples and comparative examples, the acid content of the molecular sieves was determined using an Altamira AMI-3300 instrument with NH3-TPD chemisorption-desorption curves. Before testing, the samples were activated at 550°C for 1 hour, ammonia was adsorbed at 100°C for 20 minutes, and then desorbed and detected at 100–600°C. By analyzing the Gaussian peak distribution, the acid content corresponding to desorption temperatures above 300°C was considered the acid content of strong acids.

[0058] In the context of this specification, including in the following examples and comparative examples, the yield of molecular sieves refers to the percentage of the mass of the calcined sample relative to the sum of the masses of SiO2 and Al2O3 contained in the raw material.

[0059] In the context of this specification, including in the following examples and comparative examples, the types of organic matter in the molecular sieves are determined by... 13 The chemical shifts of organic compounds in the molecular sieve were determined by comparing them with the standard chemical shifts and peak areas of N,N,N-trimethyladamantane ammonium and cyclohexylamine. The chemical shifts of standard cyclohexylamine were 50.4 ppm, 35.5 ppm, 25.8 ppm, and 24.6 ppm, and the chemical shifts of standard N,N,N-trimethyladamantane ammonium were 73.0 ppm, 48.0 ppm, 36.5 ppm, 32.5 ppm, and 29.8 ppm.

[0060] In the context of this specification, including in the following examples and comparative examples, the organic content in the molecular sieves was determined by thermogravimetric analysis (TGA) using an SDT Q600 V20.9 Build 20 instrument. The sample was heated from 50°C to 800°C at a rate of 10°C / min in air or oxygen atmosphere to detect weight loss. The percentage of weight loss of the sample within the range of 200–700°C was taken as the organic content of the sample.

[0061] The present invention will be further described in detail below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0062] Example 1

[0063] A mixture was prepared by stirring 17.47 g of deionized water, 0.635 g of sodium aluminate (containing 40.5 wt% Al₂O₃ and 30.6 wt% Na₂O), 0.218 g of sodium hydroxide, 0.32 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.19 g of cyclohexylamine (organic structure directing agent b), and 11.36 g of silica sol (containing 40.0 wt% SiO₂) at room temperature for 2 hours. The final material ratio (molar ratio) was:

[0064] SiO2 / Al2O3 = 30;

[0065] NaOH / SiO2 = 0.15;

[0066] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.005;

[0067] Cyclohexylamine / SiO2 = 0.025;

[0068] H2O / SiO2 = 18.

[0069] The mixture was placed in a stainless steel reactor and heated to crystallize at 160°C with a stirring speed of 20 rpm for 7 days. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 1 As shown in Table 1, the molecular sieves with MFI and MWW structures are symbiotic, wherein the mass content of MFI molecular sieve is 80% and the mass content of MWW molecular sieve is 20%.

[0070] Table 1

[0071]

[0072] The SiO2 / Al2O3 molar ratio of the molecular sieve was determined to be 29.6 by inductively coupled plasma atomic emission spectrometry (ICP). The chemical composition of the sample molar ratio was "1SiO2·0.033Al2O3·0.004SDA1·0.010SDA2".

[0073] After calcining the sample in air at 550℃ for 6 hours, the yield of molecular sieves was 86 wt%, and the specific surface area of ​​the molecular sieves was 472 m². 2 / gram, with an external specific surface area of ​​84 m² measured by the BET method. 2 / g; Total pore volume 0.60cm 3 / gram, micropore volume is 0.15 cm³ 3 / g. Sodium-type molecular sieves were subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 65℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type symbiotic molecular sieve samples. NH3-TPD analysis showed that the total acid content of the molecular sieve was 1171 μmol / g, and the strong acid content was 502 μmol / g.

[0074] Example 2

[0075] A mixture was prepared by stirring 9.79 g of deionized water, 0.615 g of sodium aluminate (containing 40.5 wt% Al₂O₃ and 30.6 wt% Na₂O), 0.260 g of sodium hydroxide, 0.15 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.24 g of cyclohexylamine (organic structure directing agent b), and 9.18 g of silica sol (containing 40.0 wt% SiO₂) at room temperature for 2 hours. The final material ratio (molar ratio) was:

[0076] SiO2 / Al2O3 = 25;

[0077] NaOH / SiO2 = 0.20;

[0078] N,N,N-trimethyladamantane ammonium / SiO2 = 0.003;

[0079] Cyclohexylamine / SiO2 = 0.040;

[0080] H2O / SiO2 = 14.

[0081] The mixture was placed in a stainless steel reactor and heated to crystallize at 160°C with a stirring speed of 40 rpm for 8 days. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 2As shown in Table 2, the molecular sieves with MFI and MWW structures are symbiotic, wherein the mass content of MFI molecular sieve is 91% and the mass content of MWW molecular sieve is 9%.

[0082] Table 2

[0083]

[0084]

[0085] The SiO2 / Al2O3 molar ratio of the molecular sieve was determined to be 24.6 by inductively coupled plasma atomic emission spectrometry (ICP). The chemical composition of the sample molar ratio was "1SiO2·0.040Al2O3·0.002SDA1·0.014SDA2".

[0086] After calcining the sample in air at 550℃ for 6 hours, the yield of molecular sieves was 85 wt%, and the specific surface area of ​​the molecular sieves was 491 m². 2 / gram, with an external specific surface area of ​​91 m² measured by the BET method. 2 / g; Total pore volume 0.68cm 3 / gram, micropore volume is 0.16 cm³ 3 / g. Sodium-type molecular sieves were subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 65℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type symbiotic molecular sieve samples. NH3-TPD analysis showed that the total acid content of the molecular sieve was 1307 μmol / g, and the strong acid content was 567 μmol / g.

[0087] Example 3

[0088] A mixture was prepared by stirring 22.55 g of deionized water, 0.537 g of sodium aluminate (containing 40.5 wt% Al2O3 and 30.6 wt% Na2O), 0.248 g of sodium hydroxide, 0.44 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.22 g of cyclohexylamine (organic structure directing agent b), and 11.22 g of silica sol (containing 40.0 wt% SiO2) at room temperature for 2 hours. The final material ratio (molar ratio) was:

[0089] SiO2 / Al2O3 = 35;

[0090] NaOH / SiO2 = 0.15;

[0091] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.007;

[0092] Cyclohexylamine / SiO2 = 0.030;

[0093] H2O / SiO2 = 22.

[0094] The mixture was placed in a stainless steel reactor and heated at 165°C with a stirring speed of 10 rpm for 6.5 days to crystallize. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 3 As shown in Table 3, the molecular sieves with MFI and MWW structures are symbiotic, wherein the mass content of MFI molecular sieve is 55% and the mass content of MWW molecular sieve is 45%.

[0095] Table 3

[0096]

[0097]

[0098] The SiO2 / Al2O3 molar ratio of the molecular sieve was determined to be 35.5 by inductively coupled plasma atomic emission spectrometry (ICP). The chemical composition of the sample molar ratio was "1SiO2·0.029Al2O3·0.004SDA1·0.011SDA2".

[0099] After calcining the sample in air at 550℃ for 6 hours, the yield of molecular sieves was 86 wt%, and the specific surface area of ​​the molecular sieves was 443 m². 2 / gram, with an external specific surface area of ​​79 m² measured by the BET method. 2 / g; Total pore volume 0.66cm 3 / gram, micropore volume is 0.14 cm³ 3 / g. Sodium-type molecular sieves were subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 65℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type symbiotic molecular sieve samples. NH3-TPD analysis showed that the total acid content of the molecular sieve was 947 μmol / g, and the strong acid content was 436 μmol / g.

[0100] Example 4

[0101] A mixture was prepared by stirring 41.38 g of deionized water, 0.700 g of sodium aluminate (containing 40.5 wt% Al2O3 and 30.6 wt% Na2O), 0.274 g of sodium hydroxide, 0.94 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.22 g of cyclohexylamine (organic structure directing agent b), and 16.71 g of silica sol (containing 40.0 wt% SiO2) at room temperature for 2 hours. The final material ratio (molar ratio) was:

[0102] SiO2 / Al2O3 = 40;

[0103] NaOH / SiO2 = 0.12;

[0104] N,N,N-trimethyladamantane ammonium / SiO2 = 0.010;

[0105] Cyclohexylamine / SiO2 = 0.020;

[0106] H2O / SiO2 = 26.

[0107] The mixture was placed in a stainless steel reactor and heated at 170°C with a stirring speed of 20 rpm for 5 days to crystallize. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 4 As shown in Table 4, the molecular sieves with MFI and FER structures are symbiotic, wherein the mass content of MFI molecular sieve is 60% and the mass content of FER molecular sieve is 40%.

[0108] Table 4

[0109]

[0110]

[0111] The SiO2 / Al2O3 molar ratio of the molecular sieve was determined to be 40.1 by inductively coupled plasma atomic emission spectrometry (ICP). The chemical composition of the sample molar ratio was "1SiO2·0.025Al2O3·0.004SDA1·0.009SDA2".

[0112] After calcining the sample in air at 550℃ for 6 hours, the yield of molecular sieves was 88 wt%, and the specific surface area of ​​the molecular sieves was 405 m². 2 / gram, with an external specific surface area of ​​43 m² measured by the BET method. 2 / g; Total pore volume 0.42cm 3 / gram, micropore volume is 0.14 cm³ 3 / g. Sodium-type molecular sieves were subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 65℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type symbiotic molecular sieve samples. NH3-TPD analysis showed that the total acid content of the molecular sieve was 862 μmol / g, and the strong acid content was 374 μmol / g.

[0113] Example 5

[0114] A mixture was prepared by stirring 29.43 g of deionized water, 0.516 g of sodium aluminate (containing 40.5 wt% Al2O3 and 30.6 wt% Na2O), 0.097 g of sodium hydroxide, 0.11 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.06 g of cyclohexylamine (organic structure directing agent b), and 9.84 g of silica sol (containing 40.0 wt% SiO2) at room temperature for 2 hours. The final material ratio (molar ratio) was:

[0115] SiO2 / Al2O3 = 32;

[0116] NaOH / SiO2 = 0.11;

[0117] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.002;

[0118] Cyclohexylamine / SiO2 = 0.010;

[0119] H2O / SiO2 = 30.

[0120] The mixture was placed in a stainless steel reactor and heated to crystallize at 170°C with a stirring speed of 30 rpm for 4.5 days. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 5 As shown in Table 5, the molecular sieves are composed of MFI, FER, and MWW structures, with MFI molecular sieve having a mass content of 50% and the mass ratio of MWW to FER being 3.

[0121] Table 5

[0122]

[0123]

[0124] The SiO2 / Al2O3 molar ratio of the molecular sieve was determined to be 32.3 by inductively coupled plasma atomic emission spectrometry (ICP). The chemical composition of the sample molar ratio was "1SiO2·0.031Al2O3·0.001SDA1·0.006SDA2".

[0125] After calcining the sample in air at 550℃ for 6 hours, the yield of molecular sieves was 90 wt%, and the specific surface area of ​​the molecular sieves was 438 m². 2 / gram, with an external specific surface area of ​​49 m² measured by the BET method. 2 / g; Total pore volume 0.47cm 3 / gram, micropore volume is 0.16 cm³ 3 / g. Sodium-type molecular sieves were subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 65℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type symbiotic molecular sieve samples. NH3-TPD analysis showed that the total acid content of the molecular sieve was 1026 μmol / g, and the strong acid content was 462 μmol / g.

[0126] Example 6

[0127] A mixture was prepared by stirring 54.62 g of deionized water, 0.831 g of sodium aluminate (containing 40.5 wt% Al2O3 and 30.6 wt% Na2O), 0.282 g of sodium hydroxide, 0.39 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.32 g of cyclohexylamine (organic structure directing agent b), and 13.87 g of silica sol (containing 40.0 wt% SiO2) at room temperature for 2 hours. The final material ratio (molar ratio) was:

[0128] SiO2 / Al2O3 = 28;

[0129] NaOH / SiO2 = 0.16;

[0130] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.005;

[0131] Cyclohexylamine / SiO2 = 0.035;

[0132] H2O / SiO2 = 38.

[0133] The mixture was placed in a stainless steel reactor and heated at 165°C with a stirring speed of 50 rpm for 5.5 days to crystallize. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 6As shown in Table 6, the molecular sieves with MFI, FER and MWW structures are coexisting, wherein the mass content of MFI molecular sieve is 65% and the mass ratio of MWW to FER is 0.5.

[0134] Table 6

[0135]

[0136]

[0137] The SiO2 / Al2O3 molar ratio of the molecular sieve was determined to be 27.7 using inductively coupled plasma atomic emission spectrometry (ICP). The chemical composition of the sample molar ratio was "1SiO2·0.036Al2O3·0.003SDA1·0.010SDA2".

[0138] After calcining the sample in air at 550℃ for 6 hours, the yield of molecular sieves was 85 wt%, and the specific surface area of ​​the molecular sieves was 446 m². 2 / gram, with an external specific surface area of ​​45 m² measured by the BET method. 2 / g; Total pore volume 0.44cm 3 / gram, micropore volume is 0.15 cm³ 3 / g. Sodium-type molecular sieves were subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 65℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type symbiotic molecular sieve samples. NH3-TPD analysis showed that the total acid content of the molecular sieve was 1249 μmol / g, and the strong acid content was 504 μmol / g.

[0139] Example 7

[0140] A mixture was prepared by stirring 48.97 g of deionized water, 0.794 g of sodium aluminate (containing 40.5 wt% Al2O3 and 30.6 wt% Na2O), 0.386 g of sodium hydroxide, 0.64 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.28 g of cyclohexylamine (organic structure directing agent b), and 14.22 g of silica sol (containing 40.0 wt% SiO2) at room temperature for 2 hours. The final material ratio (molar ratio) was:

[0141] SiO2 / Al2O3 = 30;

[0142] NaOH / SiO2 = 0.18;

[0143] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.008;

[0144] Cyclohexylamine / SiO2 = 0.030;

[0145] H2O / SiO2 = 34.

[0146] The mixture was placed in a stainless steel reactor and heated to crystallize at 165°C with a stirring speed of 20 rpm for 6 days. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 7 As shown in Table 7, the molecular sieves with MFI, FER and MWW structures are coexisting, wherein the mass content of MFI molecular sieve is 60% and the mass ratio of MWW to FER is 0.3.

[0147] Table 7

[0148]

[0149]

[0150] The SiO2 / Al2O3 molar ratio of the molecular sieve was determined to be 29.7 by inductively coupled plasma atomic emission spectrometry (ICP). The chemical composition of the sample molar ratio was "1SiO2·0.033Al2O3·0.005SDA1·0.011SDA2".

[0151] After calcining the sample in air at 550℃ for 6 hours, the yield of molecular sieves was 87 wt%, and the specific surface area of ​​the molecular sieves was 462 m². 2 / gram, with an external specific surface area of ​​52 m² measured by the BET method. 2 / g; Total pore volume 0.46cm 3 / gram, micropore volume is 0.15 cm³ 3 / g. Sodium-type molecular sieves were subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 65℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type symbiotic molecular sieve samples. NH3-TPD analysis showed that the total acid content of the molecular sieve was 1197 μmol / g, and the strong acid content was 489 μmol / g.

[0152] Example 8

[0153] A mixture was prepared by stirring 44.64 g of deionized water, 0.832 g of sodium aluminate (containing 40.5 wt% Al2O3 and 30.6 wt% Na2O), 0.172 g of sodium hydroxide, 0.47 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.23 g of cyclohexylamine (organic structure directing agent b), and 13.89 g of silica sol (containing 40.0 wt% SiO2) at room temperature for 2 hours. The final material ratio (molar ratio) was:

[0154] SiO2 / Al2O3 = 28;

[0155] NaOH / SiO2 = 0.13;

[0156] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.006;

[0157] Cyclohexylamine / SiO2 = 0.025;

[0158] H2O / SiO2 = 32.

[0159] The mixture was placed in a stainless steel reactor and heated at 170°C with a stirring speed of 60 rpm for 5 days to crystallize. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 8 As shown in Table 8, the molecular sieves with MFI, FER and MWW structures are coexisting, wherein the mass content of MFI molecular sieve is 45% and the mass ratio of MWW to FER is 0.2.

[0160] Table 8

[0161]

[0162]

[0163] The SiO2 / Al2O3 molar ratio of the molecular sieve was determined to be 28.3 by inductively coupled plasma atomic emission spectrometry (ICP). The chemical composition of the sample molar ratio was "1SiO2·0.035Al2O3·0.003SDA1·0.011SDA2".

[0164] After calcining the sample in air at 550℃ for 6 hours, the yield of molecular sieves was 91 wt%, and the specific surface area of ​​the molecular sieves was 472 m². 2 / gram, with an external specific surface area of ​​51 m² measured by the BET method. 2 / g; Total pore volume 0.42cm 3 / gram, micropore volume is 0.15 cm³ 3 / g. Sodium-type molecular sieves were subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 65℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type symbiotic molecular sieve samples. NH3-TPD analysis showed that the total acid content of the molecular sieve was 1270 μmol / g, and the strong acid content was 486 μmol / g.

[0165] Example 9

[0166] A mixture was prepared by stirring 39.48 g of deionized water, 0.728 g of sodium aluminate (containing 40.5 wt% Al₂O₃ and 30.6 wt% Na₂O), 0.378 g of sodium hydroxide, 0.08 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.33 g of cyclohexylamine (organic structure directing agent b), and 14.33 g of silica sol (containing 40.0 wt% SiO₂) at room temperature for 2 hours. The final material ratio (molar ratio) was:

[0167] SiO2 / Al2O3 = 33;

[0168] NaOH / SiO2 = 0.17;

[0169] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.001;

[0170] Cyclohexylamine / SiO2 = 0.035;

[0171] H2O / SiO2 = 28.

[0172] The mixture was placed in a stainless steel reactor and heated to crystallize at 160°C with a stirring speed of 10 rpm for 7.5 days. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 9 As shown in Table 9, the molecular sieves with MFI and MWW structures are symbiotic, wherein the mass content of MFI molecular sieve is 70% and the mass content of MWW molecular sieve is 30%.

[0173] Table 9

[0174]

[0175]

[0176] The SiO2 / Al2O3 molar ratio of the molecular sieve was determined to be 33.4 by inductively coupled plasma atomic emission spectrometry (ICP). The chemical composition of the sample molar ratio was "1SiO2·0.030Al2O3·0.001SDA1·0.010SDA2".

[0177] After calcining the sample in air at 550℃ for 6 hours, the yield of molecular sieve was 86 wt%, and the specific surface area of ​​the molecular sieve was 463 m². 2 / gram, with an external specific surface area of ​​98 m² measured by the BET method. 2 / g; Total pore volume 0.52cm 3 / gram, micropore volume is 0.16 cm³ 3 / g. Sodium-type molecular sieves were subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 65℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type symbiotic molecular sieve samples. NH3-TPD analysis showed that the total acid content of the molecular sieve was 987 μmol / g, and the strong acid content was 452 μmol / g.

[0178] Comparative Example 1

[0179] The material ratio is the same as in Example 1, except that N,N,N-trimethyladamantane ammonium (SDA1) is not added. The final material ratio (molar ratio) is:

[0180] SiO2 / Al2O3 = 30;

[0181] NaOH / SiO2 = 0.15;

[0182] Cyclohexylamine / SiO2 = 0.025;

[0183] H2O / SiO2 = 18.

[0184] The mixture was placed in a stainless steel reactor and heated to crystallize at 160°C with a stirring speed of 20 rpm for 7 days. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 10 As shown, the sample is an amorphous mixture of FER and MWW, which is not fully crystallized and does not contain MFI type molecular sieves.

[0185] Comparative Example 2

[0186] The material ratio is the same as in Example 1, except that less aluminum source is added. The final material ratio (molar ratio) is:

[0187] SiO2 / Al2O3 = 60;

[0188] NaOH / SiO2 = 0.15;

[0189] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.005;

[0190] Cyclohexylamine / SiO2 = 0.025;

[0191] H2O / SiO2 = 18.

[0192] The mixture was placed in a stainless steel reactor and heated at 160°C and 20 rpm for 7 days to crystallize. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 11 As shown, the sample is uncrystallized, is amorphous, and does not contain MFI molecular sieve.

[0193] Comparative Example 3

[0194] The material ratio was the same as in Example 1, except that the mixture was placed in a stainless steel reactor and heated to crystallize at 160°C and a stirring speed of 20 rpm for 3 days. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 12 As shown, the sample does not contain the MFI structure.

[0195] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A symbiotic molecular sieve containing MFI, wherein the symbiotic molecular sieve has an MFI molecular sieve and also has at least one phase selected from MWW molecular sieve and FER molecular sieve, wherein the symbiotic molecular sieve has an illustrative chemical composition as shown in the formula "mSiO2•nAl2O3•pSDA1•qSDA2", wherein 25≤m / n≤40, 100≤m / p≤1000, 0.1≤p / q≤1; SDA1 is N,N,N-trimethyladamantaneammonium, and SDA2 is cyclohexylamine.

2. The symbiotic molecular sieve according to claim 1, characterized in that, In the illustrative chemical composition of the symbiotic molecular sieve, 25≤m / n≤40, 200≤m / p≤1000, and 0.1≤p / q≤0.

5.

3. The symbiotic molecular sieve according to claim 1, characterized in that, The symbiotic molecular sieve includes X-ray diffraction patterns as shown in Table a, and at least one X-ray diffraction pattern selected from Table b or Table c; wherein, Table a is the XRD pattern of MFI molecular sieve, Table b is the XRD pattern of MWW molecular sieve, and Table c is the XRD pattern of FER molecular sieve. Table a Table b Table c a: ±0.30°, b: varies with 2θ.

4. The symbiotic molecular sieve according to claim 1, characterized in that, In the symbiotic molecular sieve, MFI molecular sieve accounts for 40% to 95% of the mass of the symbiotic molecular sieve.

5. The symbiotic molecular sieve according to claim 1, characterized in that, The symbiotic molecular sieve is an MFI / MWW / FER symbiotic molecular sieve, wherein the mass ratio of MWW molecular sieve to FER molecular sieve is 0.05~20.

6. The symbiotic molecular sieve according to claim 5, characterized in that, In the symbiotic molecular sieve, the mass ratio of MWW molecular sieve to FER molecular sieve is 0.10~10.

7. A method for preparing a symbiotic molecular sieve containing MFI, comprising the following steps: A silicon source, an aluminum source, sodium hydroxide, organic structure directing agent a, organic structure directing agent b, and water are mixed, and then the mixture is subjected to a one-step crystallization treatment to obtain the symbiotic molecular sieve. in, The silicon source is calculated as SiO2, the aluminum source as Al2O3, sodium hydroxide, organic structure directing agent a as N,N,N-trimethyladamantane ammonium, organic structure directing agent b as cyclohexylamine, and water, in a molar ratio of SiO2:Al2O3:NaOH:SDA1:SDA2:H2O=1:0.025~0.040:0.09~0.21:0.001~0.015:0.005~0.05:12~50; The crystallization conditions of the reaction mixture are 155~175℃ for 4.0~9.0 days.

8. The method for preparing the symbiotic molecular sieve according to claim 7, characterized in that, The added silicon source is calculated as SiO2, the aluminum source as Al2O3, sodium hydroxide, organic structure directing agent a as N,N,N-trimethyladamantane ammonium, organic structure directing agent b as cyclohexylamine, and water, in a molar ratio of SiO2:Al2O3:NaOH:SDA1:SDA2:H2O=1:0.025~0.040:0.10~0.20:0.001~0.010:0.01~0.04:14~40.

9. The method for preparing the symbiotic molecular sieve according to claim 7 or 8, characterized in that, The silicon source is silica sol; the aluminum source is sodium aluminate.

10. The method for preparing the symbiotic molecular sieve according to claim 7, characterized in that, The crystallization conditions of the reaction mixture are 160~170℃ for 4.5~8.0 days.

11. The method for preparing the symbiotic molecular sieve according to claim 7, characterized in that, The crystallization process of the reaction mixture is a dynamic crystallization by rotation or stirring, with a rotation or stirring speed of 10~60 rpm.

12. The method for preparing the symbiotic molecular sieve according to claim 7, characterized in that, The yield of the molecular sieve product exceeds 80%.

13. The symbiotic molecular sieve prepared according to any one of claims 1 to 6 or according to any one of claims 7 to 12 is calcined at 300 to 800°C for 1 to 10 hours to obtain a sodium-type symbiotic molecular sieve; The total specific surface area of ​​the sodium-type symbiotic molecular sieve is not less than 350 m². 2 / gram; and / or, The specific surface area of ​​the sodium-type symbiotic molecular sieve is not less than 20 m². 2 / gram; and / or, The total pore volume of the sodium-type symbiotic molecular sieve is not less than 0.30 cm³. 3 / gram; and / or, The micropore volume of the sodium-type symbiotic molecular sieve is not less than 0.14 cm³. 3 / gram.

14. The sodium-type symbiotic molecular sieve according to claim 13, characterized in that, After the symbiotic molecular sieve is calcined at 400~650℃ for 3~6 hours, a sodium-type symbiotic molecular sieve is obtained. The total specific surface area of ​​the sodium-type symbiotic molecular sieve is 350~550 m². 2 / gram; and / or, The specific surface area of ​​the sodium-type symbiotic molecular sieve is 20-120 m². 2 / gram; and / or, The total pore volume of the sodium-type symbiotic molecular sieve is 0.30~1.00 cm³. 3 / gram; and / or, The sodium-type symbiotic molecular sieve has a micropore volume of 0.14~0.20 cm³. 3 / gram.

15. The sodium-type symbiotic molecular sieve according to claim 13, characterized in that, After being treated with ammonium ion exchange to form a hydrogen-type symbiotic molecular sieve: The total acid content of the hydrogen-type symbiotic molecular sieve is not less than 800 μmol / g; and / or, The amount of strong acid in the hydrogen-type symbiotic molecular sieve is not less than 300 μmol / g.

16. The sodium-type symbiotic molecular sieve according to claim 15, characterized in that, The total acidity of the hydrogen-type symbiotic molecular sieve is 800~1400 μmol / g; and / or, The strong acid content of the hydrogen-type symbiotic molecular sieve is 300~600 μmol / g.

17. A symbiotic molecular sieve composition containing MFI, comprising a molecular sieve containing MFI prepared according to any one of claims 1 to 6 or according to any one of claims 7 to 12, and a binder.

18. The use of the MFI-containing symbiotic molecular sieve according to any one of claims 1 to 6, or the MFI-containing symbiotic molecular sieve prepared according to any one of claims 7 to 12, as an adsorbent or a catalyst for the conversion of organic compounds.

19. The use of the symbiotic molecular sieve composition containing MFI according to claim 17 as an adsorbent or a catalyst for the conversion of organic compounds.

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