High-silicon EMT molecular sieve with EMT topological structure as well as synthesis method and application of high-silicon EMT molecular sieve

Abstract

The invention discloses a high-silicon EMT molecular sieve with an EMT topological structure as well as a synthesis method and application of the high-silicon EMT molecular sieve. The anhydrous chemical composition of the molecular sieve is shown as a formula I: kM. MR. (SixAly) O2, wherein M is selected from at least one of alkali metal elements; r represents an organic template agent; k represents the mole number of the alkali metal element M corresponding to each mole of (SixAly) O2, and k is equal to 0-0.20; m represents the mole number of the template R corresponding to each mole of (SixAly) O2, and m is equal to 0.01-0.20; x and y respectively represent mole fractions of Si and Al, 2x / y = 7-40, and x + y = 1. The EMT molecular sieve provided by the invention has a silicon-aluminum oxide ratio of 7-30, high crystallinity and purity, and good hydrothermal / thermal stability, can be used for catalytic reactions such as production of high-octane gasoline by alkylation of isobutane / 2-butene, and has important significance in actual chemical production.

Description

Technical Field

[0001] The present invention relates to the technical field of molecular sieve synthesis, and in particular to a high-silicon EMT molecular sieve with an EMT topological structure, a synthesis method thereof, and applications thereof. Background Art

[0002] Although Moor et al. predicted as early as 1964 that faujasite could produce another structure through hexagonal stacking in addition to cubic (FAU) stacking, a hexagonal faujasite later named EMT, and in the decades that followed, materials codenamed CSZ-1, CSZ-3, ECR-30, ECR-35, ZSM-2, ZSM-3, and ZSM-20 were reported. These were all mixed growth materials of FAU and EMT. However, due to factors such as the lack of pure hexagonal products and limited characterization methods, they did not attract sufficient attention. It was not until Delproto et al. synthesized pure hexagonal faujasite (EMT) using crown ether as a directing agent that it attracted widespread research interest due to its two-dimensional straight pores and higher initial synthesized silicon-to-aluminum ratio compared to FAU. There have been many reports on the application of this large-pore zeolite with good industrial application prospects in catalysis and adsorption. In particular, in the catalytic reaction of isobutane / 2-butene alkylation to produce high-octane gasoline, EMT zeolite has shown superior catalytic performance to FAU.

[0003] However, the application of EMT is limited by the necessity of using excessive amounts of highly toxic and expensive templates during synthesis, as well as the significant energy consumption resulting from the long crystallization time. Therefore, it is of great practical significance to use non-toxic and inexpensive templates instead of 18-crown-6 ether to directly synthesize EMT zeolites. Summary of the Invention

[0004] In view of this, the present invention provides a high-silicon EMT molecular sieve with an EMT topological structure, a synthesis method and application thereof, the main purpose of which is to solve the technical problems of low silicon-to-aluminum ratio, low purity and crystallinity, and poor environmental protection of EMT molecular sieves.

[0005] In one aspect, the present invention provides a high-silicon EMT molecular sieve having an EMT topology, wherein the anhydrous chemical composition of the molecular sieve is as shown in Formula I:

[0006] kM·mR·(Si x Al y )O2 Formula I;

[0007] Wherein, M is selected from at least one of alkali metal elements;

[0008] R is an organic template, and R is selected from one of the quaternary phosphorus compounds;

[0009] K is per mole (Six Al y ) The number of moles of alkali metal element M corresponding to O2, k = 0 to 0.20;

[0010] m is per mole (Si x Al y ) The number of moles of O2 corresponding to the template R, m = 0.01 to 0.20;

[0011] x and y represent the mole fractions of Si and Al, respectively, 2x / y=7-40, and x+y=1.

[0012] The high-silicon EMT molecular sieve with an EMT topological structure provided by the present invention has a silicon-aluminum oxide ratio of 7 to 30, high crystallinity and purity, and good hydrothermal / thermal stability.

[0013] Optionally, M in Formula I is selected from at least one of Na, K, and Cs, and 2x / y=8-30.

[0014] Optionally, the structural formula of the quaternary phosphorus compound is as shown in Formula II;

[0015]

[0016] In formula II, R 21 、R 22 、R 23 、R 24 Each independently selected from C1 to C 12 Alkyl, C1~C 12 Alkoxy, C1~C 12 a hydroxyalkyl, aryl or adamantyl group;

[0017] X n- Selected from OH - 、Cl - Br - , I - 、NO3 - 、HSO4 - 、H2PO3 - 、SO4 2- 、HPO3 2- or PO3 3- .

[0018] Optionally, R in Formula I is selected from at least one of tetramethyl phosphonium hydroxide, tetraethyl phosphonium hydroxide, tetrapropyl phosphonium hydroxide, tetrabutyl phosphonium hydroxide, tetrapentyl phosphonium hydroxide, tetrahexyl phosphonium hydroxide, tetrapropyl phosphonium bromide, tetrabutyl phosphonium chloride, tetrapentyl phosphonium bromide, tripropyl-isobutyl phosphonium bromide, tributyl-cyclohexyl phosphonium hydroxide, dibutyl-dihexyl phosphonium hydroxide, triethyl-hydroxyethyl phosphonium hydroxide, tripropyl-hydroxyethyl phosphonium hydroxide, tributyl-hydroxyethyl phosphonium hydroxide, tributyl-benzyl phosphonium hydroxide, triethyl-benzyl phosphonium hydroxide, tripropyl-benzyl phosphonium hydroxide, N,N,N-triethyl-adamantyl phosphonium chloride and N,N,N-tripropyl-adamantyl phosphonium chloride.

[0019] Optionally, m in Formula I is selected from any value among 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19 and 0.20, or any range therebetween.

[0020] Optionally, the "C1~C 12 "C7~C 12 Phenylalkyl".

[0021] Optionally, the "aryl" includes "C7~C 12 of aromatic groups".

[0022] Optionally, the "C7~C 12 "Aryl" includes "C7~C 12 of alkylaryl".

[0023] Optionally, M is selected from at least one of Na, K, and Cs, and 2x / y=8-30.

[0024] Optionally, 2x / y is selected from any value of 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29 and 30, or a range therebetween.

[0025] In the second aspect, the present invention provides a method for synthesizing the above-mentioned high-silicon EMT molecular sieve with an EMT topological structure. By using a silicon-aluminum molecular sieve with an EMT topological structure as a seed crystal and introducing an organic template, a high-silicon (silicon-aluminum oxide molar ratio of 7 to 40) EMT molecular sieve is hydrothermally synthesized under alkaline conditions.

[0026] The synthesis method of the high-silicon EMT molecular sieve having an EMT topological structure of the present invention comprises the following steps:

[0027] a) mixing raw materials containing an aluminum source, a silicon source, an alkali metal source, an organic template R, and water to prepare an initial gel mixture I; wherein the aluminum source, silicon source, alkali metal source, organic template R, and water in the initial gel mixture I have the following molar ratio:

[0028] SiO2 / Al2O3=10~200;

[0029] M2O / Al2O3=0-30, wherein M is selected from at least one alkali metal element;

[0030] R / Al2O3=1~45;

[0031] H2O / Al2O3=100~8000;

[0032] b) adding a silicon-alumina molecular sieve seed crystal having an EMT structure to the initial gel mixture I in step a), and mixing to obtain a mixture II;

[0033] c) crystallizing the mixture II obtained in step b) under closed conditions to obtain a high-silicon EMT molecular sieve having an EMT topological structure;

[0034] Wherein, the molar number of silicon source is calculated as SiO2;

[0035] The number of moles of aluminum source is calculated as Al2O3;

[0036] The number of moles of the template agent R is calculated based on the number of moles of R itself;

[0037] The molar number of the alkali metal source is calculated as the molar number of the metal oxide M2O of the corresponding alkali metal M.

[0038] Optionally, in step a), the organic template R is selected from at least one of quaternary phosphorus compounds; the structural formula of the quaternary phosphorus compound is shown in Formula II;

[0039]

[0040] In formula II, R 21 、R 22 、R 23 、R 24 Each independently selected from C1 to C 12 Alkyl, C1~C 12 Alkoxy, C1~C 12 a hydroxyalkyl, aryl or adamantyl group;

[0041] X n- Selected from OH - 、Cl - Br - , I - 、NO3- 、HSO4 - 、H2PO3 - 、SO4 2- 、HPO3 2- or PO3 3- .

[0042] Optionally, in Formula II, the "C1 to C 12 "C7~C 12 Phenylalkyl".

[0043] Optionally, in Formula II, the "aryl" includes "C7~C 12 of aromatic groups".

[0044] Optionally, in Formula II, the "C7 to C 12 "Aryl" includes "C7~C 12 of alkylaryl".

[0045] Optionally, the organic template R in step a) is selected from at least one of tetramethyl phosphonium hydroxide, tetraethyl phosphonium hydroxide, tetrapropyl phosphonium hydroxide, tetrabutyl phosphonium hydroxide, tetrapentyl phosphonium hydroxide, tetrahexyl phosphonium hydroxide, tetrapropyl phosphonium bromide, tetrabutyl phosphonium chloride, tetrapentyl phosphonium bromide, tripropyl-isobutyl phosphonium bromide, tributyl-cyclohexyl phosphonium hydroxide, dibutyl-dihexyl phosphonium hydroxide, triethyl-hydroxyethyl phosphonium hydroxide, tripropyl-hydroxyethyl phosphonium hydroxide, tributyl-hydroxyethyl phosphonium hydroxide, tributyl-benzyl phosphonium hydroxide, triethyl-benzyl phosphonium hydroxide, tripropyl-benzyl phosphonium hydroxide, N,N,N-triethyl-adamantyl phosphonium chloride and N,N,N-tripropyl-adamantyl phosphonium chloride.

[0046] Optionally, the silicon source in step a) is selected from at least one of methyl orthosilicate, ethyl orthosilicate, silica sol, solid silica gel, white carbon black, and sodium silicate;

[0047] The aluminum source in step a) is selected from at least one of sodium metaaluminate, aluminum oxide, aluminum hydroxide, aluminum isopropoxide, aluminum 2-butoxide, aluminum chloride, aluminum sulfate, aluminum nitrate, and pseudo-boehmite;

[0048] The alkali metal source in step a) is selected from at least one of sodium hydroxide, potassium hydroxide and cesium hydroxide.

[0049] Optionally, step a) comprises: mixing an aluminum source, an alkali metal source, an organic template R and water, and then adding a silicon source, and mixing to obtain an initial gel mixture I.

[0050] Optionally, the aluminum source, silicon source, alkali metal source, organic template R and water in the initial gel mixture I in step a) have the following molar ratio:

[0051] SiO2 / Al2O3=10~200;

[0052] M2O / Al2O3=0-30, wherein M is selected from at least one alkali metal element;

[0053] R / Al2O3=1~45;

[0054] H2O / Al2O3=100~6000.

[0055] Optionally, in the initial gel mixture I, the molar ratio of SiO2 / Al2O3 is selected from any value among 10, 15, 20, 30, 40, 45, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190 and 200, or any range value therebetween.

[0056] Optionally, the molar ratio of M2O / Al2O3 is selected from any value among 0.1, 1.8, 2.0, 3.0, 4.0, 4.5, 4.8, 5.0, 6.0, 7.0, 8.0, 9.0, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 22, 25, 28, 29 and 30, or any range therebetween.

[0057] Optionally, the molar ratio of R / Al2O3 is selected from any value among 1, 2, 3, 3.6, 4, 4.5, 4.8, 5, 5.2, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 22, 25, 28, 29, 30, 32, 35, 38, 40, 42 and 45, or any range therebetween.

[0058] Optionally, the molar ratio of H2O / Al2O3 is selected from any value among 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3200, 3500, 3800, 4000, 5000 and 6000, or any range therebetween.

[0059] Optionally, in step b), the mass ratio of the added amount of the silicon-aluminum molecular sieve seeds with EMT structure in the mixture II to the silicon source in the initial gel mixture I in step a) is 0.05 to 0.3:1; wherein the mass of the silicon source in the initial gel mixture I is measured in terms of the mass of SiO2.

[0060] Optionally, the mass ratio of the amount of the silicon-aluminum molecular sieve seeds with an EMT structure added to the mixture II in step b) to the silicon source (in terms of silicon dioxide) in the initial gel mixture I is selected from any ratio of 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1, 0.11:1, 0.12:1, 0.13:1, 0.14:1, 0.15:1, 0.20:1, 0.30:1 and the range value between any two of the ratios.

[0061] Optionally, in step b), the silicon-aluminum molecular sieve seed crystal having an EMT structure has a silicon-aluminum molar ratio SiO2 / Al2O3 of 2 to ∞;

[0062] Optionally, the silicon-aluminum molecular sieve seed crystal with an EMT structure in step b) has a silicon-aluminum molar ratio SiO2 / Al2O3 of 2.5 to 200.

[0063] Optionally, the silicon-aluminum molecular sieve seed crystal with an EMT structure in step b) has a silicon-aluminum molar ratio SiO2 / Al2O3 of 2.5 to 30.

[0064] Optionally, the silicon-aluminum molecular sieve seed crystal with an EMT structure in step b) has a silicon-aluminum molar ratio SiO2 / Al2O3 of 2.5 to 20.

[0065] Optionally, the silicon-aluminum molecular sieve seed crystal with an EMT structure in step b) has a silicon-aluminum molar ratio SiO2 / Al2O3 of 3 to 10.

[0066] Optionally, the silicon-aluminum molar ratio SiO2 / Al2O3 of the silicon-aluminum molecular sieve seed with an EMT structure in step b) is selected from any value among 2.2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 and 30, or a range value between any two of them.

[0067] Optionally, in step c), the crystallization temperature is 90 to 180° C., and the crystallization time is 0.1 to 15 days.

[0068] Optionally, the crystallization temperature in step c) is any value selected from 90°C, 100°C, 110°C, 120°C, 140°C, 160°C and 180°C, or any range between two of them.

[0069] Optionally, the crystallization time in step c) is selected from any value among 0.1 day, 0.5 day, 1 day, 1.5 days, 2.5 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, 14 days and 15 days, or any range value therebetween.

[0070] Optionally, the crystallization in step c) is carried out by dynamic crystallization and / or static crystallization.

[0071] Optionally, the crystallization method in step c) is rotational crystallization.

[0072] As a specific embodiment, the method includes the following steps:

[0073] a) mixing raw materials of an aluminum source, a silicon source, an alkali metal source, an organic template R, and water to prepare an initial gel mixture I; wherein the aluminum source, the silicon source, the alkali metal source, the organic template R, and the water in the raw materials have the following molar ratio:

[0074] SiO2 / Al2O3=10~200;

[0075] M2O / Al2O3=0-30, wherein M is selected from at least one alkali metal element;

[0076] R / Al2O3=1~45;

[0077] H2O / Al2O3=100~8000

[0078] b) adding silicon-alumina molecular sieve seed crystals having an EMT structure to the initial gel mixture I obtained in step a), and mixing to obtain a mixture II;

[0079] c) placing the mixture II obtained in step b) in a sealed reactor for crystallization at a temperature of 80 to 180° C., a crystallization pressure of autogenous pressure, and a crystallization time of 0.1 to 15 days; after the crystallization is completed, the obtained product is separated, washed, and dried to obtain the high-silicon EMT molecular sieve having an EMT topological structure;

[0080] The molar number of the silicon source is calculated as SiO2; the molar number of the aluminum source is calculated as Al2O3; the molar number of the template R is calculated as the molar number of R itself; and the molar number of the alkali metal is calculated as the molar number of its corresponding metal oxide M2O.

[0081] As a specific embodiment, the synthesis process of the high-silicon EMT molecular sieve with EMT topology is as follows:

[0082] a) Preparation of initial gel: aluminum source, silicon source, alkali metal source, organic template R and deionized water in the following proportions:

[0083] SiO2 / Al2O3=10~200;

[0084] M2O / Al2O3=0-30, wherein M is selected from at least one alkali metal element;

[0085] R / Al2O3=1~45;

[0086] H2O / Al2O3=100~8000

[0087] The mixture was mixed and stirred at room temperature to obtain an initial gel;

[0088] b) adding silicon-alumina molecular sieve seed crystals having an EMT structure to the initial gel mixture obtained in step a) and stirring uniformly, wherein the mass ratio of the added seed crystals to the SiO2 in the initial gel mixture is 0.05 to 0.3:1;

[0089] c) crystallizing the mixture obtained in step b) at 80-180° C. under autogenous pressure for 0.1-15 days. After the crystallization is completed, the solid product is separated by filtration, washed with deionized water until neutral, and dried to obtain a high-silicon EMT molecular sieve.

[0090] In a third aspect, the present invention provides a catalyst, which includes the above-mentioned high-silicon EMT molecular sieve with an EMT topological structure or the high-silicon EMT molecular sieve with an EMT topological structure prepared by the above-mentioned method.

[0091] In a fourth aspect, the present invention provides the use of the above-mentioned high-silicon EMT molecular sieve with EMT topology structure or the high-silicon EMT molecular sieve with EMT topology structure prepared by the above-mentioned method or the above-mentioned catalyst in the alkylation of isobutane / 2-butene to produce high-octane gasoline.

[0092] In this application, C1~C 12 、C7~C 12 etc. refer to the number of carbon atoms contained. For example, "C1~C 12 The term "alkyl" refers to an alkyl group having 1 to 12 carbon atoms.

[0093] In this application, "alkyl" refers to a group formed by losing any hydrogen atom from an alkane compound molecule. The alkane compound includes straight-chain alkanes, branched-chain alkanes, cycloalkanes, and branched cycloalkanes.

[0094] In the present application, "alkoxy" is a group formed by losing the hydrogen atom on the -OH group of an alkyl alcohol compound molecule. For example, a methoxy group -OCH3 is formed by losing the hydrogen atom on the -OH group of a CH3OH molecule.

[0095] In this application, "hydroxyalkyl" refers to a group formed by losing any hydrogen atom other than the -OH group in an alkyl alcohol molecule, such as HOCH2-, which is formed by losing the hydrogen atom of the methyl group in the CH3OH molecule.

[0096] In the present application, "aryl" is a group formed by losing a hydrogen atom on the aromatic ring of an aromatic compound molecule; for example, toluene loses the hydrogen atom at the para position of the methyl group on the benzene ring to form p-tolyl.

[0097] In the present application, "alkylphenyl" is a group formed when a benzene ring containing a substituent loses a hydrogen atom; for example, toluene loses a hydrogen atom at the para position of the methyl group on the benzene ring to form p-tolyl.

[0098] In the present application, "phenylalkyl" refers to a group formed by losing any hydrogen atom from an alkyl substituent on a benzene ring; for example, a benzyl group (benzyl) is formed by losing a hydrogen atom from a methyl group on toluene.

[0099] Compared with the prior art, the present invention has the following beneficial effects:

[0100] 1) In the present application, a high-silicon EMT molecular sieve with a silicon-aluminum oxide ratio of 7 to 30 is synthesized by introducing an organic template into the synthesis gel and adding a silicon-aluminum molecular sieve with an EMT topological structure as a seed crystal.

[0101] 2) The high silicon-aluminum ratio EMT molecular sieve synthesized in this application has high crystallinity and purity, good hydrothermal / thermal stability, and can be used in catalytic reactions such as isobutane / 2-butene alkylation to produce high-octane gasoline, which is of great significance in the field of actual chemical production. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] Figure 1 is the X-ray diffraction (XRD) spectrum of sample X1 in Example 1 of the present invention;

[0103] Figure 2 is a scanning electron microscope (SEM) image of sample X1 in Example 1 of the present invention;

[0104] Figure 3 The silicon nuclear magnetic resonance ( 29 Si-NMR) spectrum;

[0105] Figure 4 It is the X-ray diffraction (XRD) spectrum of sample V1 of comparative example 1 of the present invention. DETAILED DESCRIPTION

[0106] The present application will be further described below in conjunction with specific embodiments. The following description is merely a few embodiments of the present application and does not limit the present application in any form. Although the present application discloses the preferred embodiments below, it is not intended to limit the present application. Any person skilled in the art who, without departing from the scope of the technical solution of the present application, makes slight changes or modifications using the above disclosed technical content is equivalent to an equivalent implementation case and falls within the scope of the technical solution.

[0107] The analysis method in the examples of this application is as follows:

[0108] The X-ray powder diffraction (XRD) analysis of the product was performed using an X'Pert PRO X-ray diffractometer from PANalytical of the Netherlands, with a Cu target, a Kα radiation source (λ=0.15418 nm), a voltage of 40 KV, and a current of 40 mA.

[0109] The scanning electron microscope (SEM) test instrument used was a Hitachi SU8020 field emission scanning electron microscope with an accelerating voltage of 2 kV.

[0110] The elemental composition was determined using a Philips Magix 2424 X-ray fluorescence analyzer (XRF).

[0111] Si-NMR ( 29 Si-NMR experiments were performed on a Bruker Avance III 600 (14.1 Tesla) spectrometer using a 7 mm double-resonance probe at 6 kHz. A high-power proton decoupling program was used, with a sampling frequency of 1024, a π / 4 pulse width of 2.5 μs, and a sampling delay of 10 s. Chemical shifts were referenced to sodium 4,4-dimethyl-4-propanesulfonate (DSS) and calibrated to 0 ppm.

[0112] Carbon NMR ( 13 C MAS NMR experiments were performed on a Bruker Avance III 600 (14.1 Tesla) spectrometer using a 4 mm triple resonance probe at a rotation speed of 12 kHz. Amantadine was used as the chemical shift reference and the chemical shift was calibrated to 0 ppm.

[0113] Example 1 (Preparation of Sample X1)

[0114] Preparation of synthetic gel: 0.7 g of sodium aluminate (Al2O3: 48.3 wt%, Na2O: 36.3 wt%, China Pharmaceutical (Group) Shanghai Chemical Reagent Company), 0.20 g of sodium hydroxide, and 13.0 g of tetrapropylphosphine hydroxide (25 wt%) were dissolved in 2.40 g of deionized water and stirred until clear, and 14.7 g of silica sol (SiO2: 30 wt%, Shenyang Chemical Co., Ltd.) was added dropwise and stirred for 0.5 h, and then 0.4 g of Y zeolite with a silicon-aluminum oxide ratio of 3 was added as a seed crystal, and stirring was continued for 2 h.

[0115] Synthesis of high-silica EMT zeolite: The synthetic gel was transferred into a stainless steel reactor and crystallized at 130°C for 5 days. After the crystallization, the solid and liquid were separated and washed to neutrality, and dried at 100°C for 12 hours. This was recorded as sample X1.

[0116] The X-ray powder diffraction pattern (XRD) of sample X1 is as follows: Figure 1 As shown, it shows that sample 1 is a molecular sieve with an EMT framework structure. Figure 2 As shown, sample 1 is a thin sheet with a thickness of 50nm to 100nm. 29 Si MAS NMR spectrum is as follows Figure 3 As shown in the figure, the framework silicon-aluminum ratio obtained by fitting calculation is consistent with that calculated by XRF. 13 The elemental composition of sample 1 obtained by normalization of C MAS NMR analysis is: 0.07Na·0.07R·(Si 0.86 Al 0.14 )O2, wherein R is tetrapropylphosphonium hydroxide.

[0117] Example 2 (Preparation of Samples X2-X30)

[0118] The preparation process of samples X2-X30 is the same as that of Example 1. The types of raw materials, molar ratios, seed crystal addition amounts (mass ratio of seed crystals to SiO2 in gel), crystallization conditions, crystal structures, silicon-aluminum ratios (the silicon-aluminum ratios of the products are determined by X-ray fluorescence analyzer (XRF)), and product compositions of samples X2-X30 are shown in Table 1.

[0119] In the preparation of samples X1 to X20, silicon-aluminum molecular sieves with an EMT structure and a silicon-aluminum oxide ratio of 3, 2.8, 3, 3.5, 45, 6, 6, 6, 7, 70, 10, 4, 5, 6, 8, 3.5, 35, 12, and 20 were used as seeds, respectively. The molecular sieve seeds were purchased from Zibo Runxin Chemical Technology Co., Ltd. In the preparation of samples X21 to X30, silicon-aluminum molecular sieves with an EMT structure and a silicon-aluminum oxide ratio of 10, 8, 8.5, 7, 7, 8, 21, 7, 8, and 22 were used as seeds, respectively. The molecular sieve seeds were purchased from Henan Huanyu Molecular Sieve Co., Ltd.

[0120] Comparative Example 1 (Preparation of Comparative Samples V1-V30)

[0121] Comparative Example 1 differs from Example 1 in that no seeding step is performed. The specific raw material types, molar ratios, batching process, and crystallization conditions for synthesizing the gel were the same as those for Sample 1# in Example 1. The raw material types, molar ratios, crystallization conditions, and product crystal structures for each product are detailed in Table 2. The resulting samples are designated Comparative Samples V1-V30.

[0122] Example 3 (Characterization and Analysis of Samples X1-X30 and Comparative Samples V1-V30)

[0123] The phases of samples X1-X30 and comparative samples V1-V30 were analyzed by X-ray diffraction.

[0124] The results show that the samples X1-X30 prepared in Examples 1 and 2 are all high purity and high crystallinity Y-type molecular sieves, such as Figure 1 The XRD spectrum of sample X1 is shown in Figure 2. Figure 2 is the SEM image of X1, Figure 3 is the silicon NMR of sample X1. The XRD spectrum results of samples X2-X30 are similar to Figure 1 The diffraction peak positions and shapes are basically the same, and the relative peak intensity fluctuates within the range of ±5% depending on the changes in the synthesis conditions, indicating that samples X1-X30 have the structural characteristics of Y-type zeolite and are free of impurity crystals. The silicon-aluminum ratio is much higher than that of conventional Y zeolite. The introduction of organic templates is the key to the synthesis of high-silicon EMT zeolite.

[0125] The products V1-V30 in Table 2 are all amorphous, and typical examples are Figure 4 The XRD spectrum of the comparative sample V1 shows that in the synthesis of high-silicon EMT zeolite, in addition to the organic template, the introduction of seed crystals is also necessary.

[0126] Table 1. Raw material types, molar ratios, seed addition amounts, crystallization conditions, crystal structures, Si / Al ratios, and product compositions of samples X1-X30

[0127]

[0128]

[0129]

[0130] Note: Al2O3 1 :Alumina; SiO2 1 : Silica sol; R2 1 :Tetrapropylphosphonium hydroxide

[0131] Al2O3 2:Aluminum isopropylate; SiO2 2 : Ethyl orthosilicate; R2 2 :Triethylhexyl phosphonium hydroxide

[0132] Al2O3 3 :Sodium aluminate; SiO2 3 :Silica; R2 3 :Triethylbenzylphosphonium hydroxide

[0133] Al2O3 4 :Aluminum nitrate; SiO2 4 :Silica gel R2 4 :N,N,N-tripropylammonium phosphonium hydroxide Al2O3 5 :2-butoxide aluminum; R2 5 :Dipropyldibutylphosphonium hydroxide

[0134] Al2O3 6 :Aluminum sulfate; R2 6 :Benzyltripropylphosphonium hydroxide

[0135] Al2O3 7 :Aluminum powder; R2 7 :Benzyltrimethylphosphonium hydroxide

[0136] R2 8 :Tetrabutylphosphonium hydroxide

[0137] R2 9 :Tetrahexylphosphonium hydroxide

[0138] R2 10 :Tributyl-hydroxyethyl phosphonium hydroxide

[0139] R2 11 :Tripropyl-hydroxyethyl phosphonium hydroxide

[0140] Table 2. Raw material types, molar ratios, crystallization conditions, and crystal structures of samples V1-V30

[0141]

[0142]

[0143]

[0144] Note: Al2O3 1 :Aluminum oxide; DiO2 1 : Silica sol; R2 1 :Tetrapropylphosphonium hydroxide

[0145] Al2O3 2 :Aluminum isopropylate; DiO22 : Ethyl orthosilicate; R2 2 :Triethylhexylphosphonium hydroxide

[0146] Al2O3 3 :Sodium aluminate; DiO2 3 : White carbon black; R2 3 :Triethylbenzylphosphonium hydroxide

[0147] Al2O3 4 :Aluminum nitrate; DiO2 4 :Silica gel R2 4 :N,N,N-tripropylammonium phosphonium hydroxide

[0148] Al2O3 5 :2-butoxide aluminum; R2 5 :Dipropyldibutylphosphonium hydroxide

[0149] Al2O3 6 : Aluminum sulfate; R2 6 :Benzyltripropylphosphonium hydroxide

[0150] Al2O3 7 :Aluminum powder; R2 7 :Benzyltrimethylphosphonium hydroxide

[0151] R2 8 :Tetrabutylphosphonium hydroxide

[0152] R2 9 :Tetrahexylphosphonium hydroxide

[0153] R2 10 :Tributyl-hydroxyethyl phosphonium hydroxide

[0154] R2 11 :Tripropyl-hydroxyethyl phosphonium hydroxide

[0155] The above descriptions are merely a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, they are not intended to limit the present application. Any technical personnel familiar with the present profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A high-silicon EMT molecular sieve with an EMT topological structure, characterized in that: The anhydrous chemical composition of the molecular sieve is shown in Formula I: kM·mR·(Si x Al y )O2 of formula I; Wherein, M is selected from at least one of alkali metal elements; R is an organic template, and R is selected from one of quaternary phosphorus compounds; K is per mole (Si x Al y )O2 corresponds to the number of moles of the alkali metal element M, k = 0 to 0.20; m is per mole (Si x Al y ) The molar number of O2 corresponding to the template R, m = 0.01 ~ 0.20; x and y represent the molar fractions of Si and Al, respectively, 2x / y=7-40, and x+y=1.

2. The high-silicon EMT molecular sieve with an EMT topological structure according to claim 1, characterized in that: In Formula I, M is selected from at least one of Na, K and Cs, and 2x / y=8 to 30; Preferably, the structural formula of the quaternary phosphorus compound is as shown in Formula II; In formula II, R 21 , R 22 , R 23 , R 24 Each independently selected from C1 to C 12 Alkyl, C1~C 12 Alkoxy, C1~C 12 A hydroxyalkyl group, an aryl group or an adamantyl group; X n- Selected from OH - , Cl - Br - ,I - 、NO3 - 、HSO4 - 、H2PO3 - 、SO4 2- 、HPO3 2- or PO3 3- .

3. The high-silicon EMT molecular sieve with EMT topological structure according to claim 1, characterized in that: R in Formula I is selected from at least one of tetramethyl phosphonium hydroxide, tetraethyl phosphonium hydroxide, tetrapropyl phosphonium hydroxide, tetrabutyl phosphonium hydroxide, tetrapentyl phosphonium hydroxide, tetrahexyl phosphonium hydroxide, tetrapropyl phosphonium bromide, tetrabutyl phosphonium chloride, tetrapentyl phosphonium bromide, tripropyl-isobutyl phosphonium bromide, tributyl-cyclohexyl phosphonium hydroxide, dibutyl-dihexyl phosphonium hydroxide, triethyl-hydroxyethyl phosphonium hydroxide, tripropyl-hydroxyethyl phosphonium hydroxide, tributyl-hydroxyethyl phosphonium hydroxide, tributyl-benzyl phosphonium hydroxide, triethyl-benzyl phosphonium hydroxide, tripropyl-benzyl phosphonium hydroxide, N,N,N-triethyl-adamantyl phosphonium chloride and N,N,N-tripropyl-adamantyl phosphonium chloride.

4. A method for synthesizing a high-silicon EMT molecular sieve having an EMT topological structure according to any one of claims 1 to 3, characterized in that: The following steps are involved: a) mixing raw materials containing an aluminum source, a silicon source, an alkali metal source, an organic template R and water to prepare an initial gel mixture I; the aluminum source, the silicon source, the alkali metal source, the organic template R and the water in the initial gel mixture I have the following molar ratio: SiO2 / Al2O3=10-200; M2O / Al2O3=0-30, wherein M is selected from at least one of alkali metal elements; R / Al2O3=1-45; H2O / Al2O3=100-8000; b) adding silicon-alumina molecular sieve seed crystals having an EMT structure to the initial gel mixture I in step a), and mixing to obtain a mixture II; c) crystallizing the mixture II obtained in step b) under closed conditions to obtain a high-silicon EMT molecular sieve with an EMT topological structure; Wherein, the molar number of silicon source is calculated as SiO2; The molar number of aluminum source is calculated as Al2O3; The molar number of the template agent R is calculated based on the molar number of R itself; The molar number of the alkali metal source is calculated based on the molar number of the metal oxide M2O of the corresponding alkali metal M.

5. The method for synthesizing a high-silicon EMT molecular sieve having an EMT topological structure according to claim 4, characterized in that: In step a), the organic template R is selected from at least one of quaternary phosphorus compounds; the structural formula of the quaternary phosphorus compound is shown in Formula II; In formula II, R 21 , R 22 , R 23 , R 24 Each independently selected from C1 to C 12 Alkyl, C1~C 12 Alkoxy, C1~C 12 A hydroxyalkyl group, an aryl group or an adamantyl group; X n- Selected from OH - , Cl - Br - ,I - 、NO3 - 、HSO4 - 、H2PO3 - 、SO4 2- 、HPO3 2- or PO3 3- ; Preferably, the organic template R in step a) is selected from at least one of tetramethyl phosphonium hydroxide, tetraethyl phosphonium hydroxide, tetrapropyl phosphonium hydroxide, tetrabutyl phosphonium hydroxide, tetrapentyl phosphonium hydroxide, tetrahexyl phosphonium hydroxide, tetrapropyl phosphonium bromide, tetrabutyl phosphonium chloride, tetrapentyl phosphonium bromide, tripropyl-isobutyl phosphonium bromide, tributyl-cyclohexyl phosphonium hydroxide, dibutyl-dihexyl phosphonium hydroxide, triethyl-hydroxyethyl phosphonium hydroxide, tripropyl-hydroxyethyl phosphonium hydroxide, tributyl-hydroxyethyl phosphonium hydroxide, tributyl-benzyl phosphonium hydroxide, triethyl-benzyl phosphonium hydroxide, tripropyl-benzyl phosphonium hydroxide, N,N,N-triethyl-adamantyl phosphonium chloride and N,N,N-tripropyl-adamantyl phosphonium chloride.

6. The method for synthesizing a high-silicon EMT molecular sieve having an EMT topological structure according to claim 4, characterized in that: The silicon source in step a) is selected from at least one of methyl orthosilicate, ethyl orthosilicate, silica sol, solid silica gel, white carbon black, and sodium silicate; The aluminum source in step a) is selected from at least one of sodium aluminate, aluminum oxide, aluminum hydroxide, aluminum isopropoxide, aluminum 2-butoxide, aluminum chloride, aluminum sulfate, aluminum nitrate, and pseudo-boehmite; The alkali metal source in step a) is selected from at least one of sodium hydroxide, potassium hydroxide and cesium hydroxide; Preferably, step a) comprises: mixing an aluminum source, an alkali metal source, an organic template R and water, and then adding a silicon source, and mixing to obtain an initial gel mixture I.

7. The method for synthesizing a high-silicon EMT molecular sieve having an EMT topological structure according to claim 4, characterized in that: The aluminum source, silicon source, alkali metal source, organic template R and water in the initial gel mixture I in step a) have the following molar ratio: SiO2 / Al2O3=10-200; M2O / Al2O3=0-30, wherein M is selected from at least one of alkali metal elements; R / Al2O3=1-45; H2O / Al2O3=100~6000.

8. The method for synthesizing a high-silicon EMT molecular sieve having an EMT topological structure according to claim 4, characterized in that: In step b), the mass ratio of the amount of the silicon-aluminum molecular sieve seed with EMT structure added in the mixture II to the silicon source in the initial gel mixture I in step a) is 0.05-0.3:1; wherein the mass of the silicon source in the initial gel mixture I is calculated as the mass of SiO2; Preferably, in step b), the silicon-aluminum molar ratio SiO2 / Al2O3 of the silicon-aluminum molecular sieve seed with EMT structure is 2 to ∞; Preferably, the silicon-aluminum molecular sieve seed crystal with an EMT structure in step b) has a silicon-aluminum molar ratio SiO2 / Al2O3 of 2.5 to 200.

9. The method for synthesizing a high-silicon EMT molecular sieve having an EMT topological structure according to claim 4, characterized in that: In step c), the crystallization temperature is 90 to 180° C., and the crystallization time is 0.1 to 15 days; Preferably, the crystallization in step c) is carried out by dynamic crystallization and / or static crystallization.

10. Use of the high-silicon EMT molecular sieve according to any one of claims 1 to 3 or the high-silicon EMT molecular sieve synthesized by the synthesis method according to any one of claims 4 to 9 in the alkylation of isobutane / 2-butene to produce high-octane gasoline.

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