High-silicon emt molecular sieve, synthesis method and application thereof

Abstract

The application discloses high-silicon EMT molecular sieve and a synthesis method and application thereof, and belongs to the technical field of molecular sieves. The synthesis method of the EMT molecular sieve comprises the following steps: a) mixing an aluminum source Al 1 , a silicon source Si 1 , an alkali metal source M 1 , an organic template agent R 1 and water to obtain raw material I, and obtaining a directing agent after aging of the raw material I; b) mixing an aluminum source Al 2 , a silicon source Si 2 , an alkali metal source M 2 , an organic template agent R 2 and water to obtain raw material II, namely, an initial gel; c) adding the directing agent into the initial gel, stirring uniformly, and placing in a sealed reaction kettle to perform crystallization, so that the high-silicon EMT molecular sieve with an EMT topological structure is obtained. The EMT molecular sieve disclosed by the application has a high silicon-aluminum oxide ratio of 7-30, high crystallinity and purity, and good hydrothermal / thermal stability, and can be used in catalytic reactions such as production of high-octane gasoline through isobutane / 2-butene alkylation, and has important significance in actual chemical production.

Description

Technical Field

[0001] This invention relates to the field of molecular sieve synthesis technology, and in particular to a high-silica EMT molecular sieve, its synthesis method, and its applications. Background Technology

[0002] Although Moor et al. predicted as early as 1964 that octahedral zeolite could also produce another structure through hexagonal stacking in addition to cubic stacking (FAU), namely hexagonal octahedral zeolite later named EMT, and in the decades that followed, materials with the codes CSZ-1, CSZ-3, ECR-30, ECR-35, ZSM-2, ZSM-3, and ZSM-20 were successively reported, all of which were mixed growth materials of FAU and EMT, they did not attract enough attention due to the lack of pure hexagonal phase products and limitations in characterization methods. It was not until Delproto et al. synthesized pure hexagonal octahedral zeolite (EMT) using crown ether as a directing agent that it attracted widespread research interest due to its two-dimensional through-pores and higher initial synthesis silica-alumina ratio compared to FAU. There have been many reports on the application of this macroporous zeolite with good industrial application prospects in catalysis and adsorption, especially in the catalytic reaction of isobutane / 2-butene alkylation to produce high octane gasoline, where EMT zeolite has shown superior catalytic performance compared to FAU.

[0003] However, the application of EMT is limited by the need for excessive amounts of highly toxic and expensive template agents during synthesis, as well as the enormous energy consumption resulting from the long crystallization time. Therefore, the direct synthesis of EMT zeolites using non-toxic and inexpensive template agents to replace 18-crown-6 ethers is of significant practical importance. Summary of the Invention

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

[0005] On the one hand, the present invention provides a high-silica EMT molecular sieve, the anhydrous chemical structural formula of which is Formula I:

[0006] kM·mR 1 ·nR 2 · (Si x Al y O2 formula I;

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

[0008] R 1 R 2 It is an organic template agent; R 1 R2 Each is independently selected from one of the quaternary phosphorus compounds;

[0009] k is the number of moles (Si) x Al y The number of moles of the alkali metal element M corresponding to O2, k = 0~0.20;

[0010] m and n are respectively per mole (Si) x Al y O2 corresponds to the template agent R 1 R 2 The number of moles, m = 0.01~0.20, n = 0.01~0.20;

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

[0012] The high-silica EMT molecular sieve with EMT topology provided by this invention has a silicon-aluminum oxide ratio of 7 to 30. This molecular sieve has high crystallinity and purity, and good hydrothermal / thermal stability.

[0013] Optionally, the quaternary phosphorus compound has the structural formula of Formula II:

[0014] Formula II;

[0015] In Equation II, R 21 R 22 R 23 and R 24 Each is independently selected from C1 to C2. 12 Alkyl, C1~C 12 alkoxy groups, C1~C 12 hydroxyalkyl, C7~C 12 Benzenealkyl, C7~C 12 Alkylphenyl or adamantyl;

[0016] X n- Selected from OH - Cl - ,Br - I - NO3 - HSO4 - H2PO3 - SO4 2- HPO3 2- or PO3 3- ;

[0017] Optionally, M in Formula I is selected from at least one of Na, K, and Cs; 2x / y = 8~30.

[0018] Optionally, 2x / y is selected from any value among 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 between any two.

[0019] Optionally, the high-silica EMT molecular sieve has an EMT topology, and the silicon-aluminum oxide ratio of the molecular sieve is 7~30.

[0020] Optionally, the silica-alumina oxide ratio of the molecular sieve is selected from any value or a range between any two of 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.

[0021] Optionally, R in Equation I 1 R 2 Each of the following is independently selected from at least one of tetramethyl phosphorus hydroxide, tetraethyl phosphorus hydroxide, tetrapropyl phosphorus hydroxide, tetrabutyl phosphorus hydroxide, tetrapentyl phosphorus hydroxide, tetrahexyl phosphorus hydroxide, tetrapropyl phosphorus bromide, tetrabutyl phosphorus chloride, tetrapentyl phosphorus bromide, tripropyl-isobutyl phosphorus bromide, tributyl-cyclohexyl phosphorus hydroxide, dibutyl-dihexyl phosphorus hydroxide, choline, triethyl-hydroxyethyl phosphorus hydroxide, tripropyl-hydroxyethyl phosphorus hydroxide, tributyl-hydroxyethyl phosphorus hydroxide, tributyl-benzyl phosphorus hydroxide, triethyl-benzyl phosphorus hydroxide, tripropyl-benzyl phosphorus hydroxide, N,N,N-triethyl-adamantyl phosphorus chloride, and N,N,N-tripropyl-adamantyl phosphorus chloride.

[0022] Optionally, R in Equation I 1 Selected from at least one of tetramethylphosphorus hydroxide, tetraethylphosphorus hydroxide, and tetrapropylphosphorus hydroxide;

[0023] R in Equation I 2 It is selected from at least one of tetraethyl phosphorus hydroxide, tetrapropyl phosphorus hydroxide, tetrabutyl phosphorus hydroxide, tetrapentyl phosphorus hydroxide, tetrahexyl phosphorus hydroxide, tetrapropyl phosphorus bromide, tetrabutyl phosphorus chloride, tetrapentyl phosphorus bromide, tripropyl-isobutyl phosphorus bromide, tributyl-cyclohexyl phosphorus hydroxide, dibutyl-dihexyl phosphorus hydroxide, choline, triethyl-hydroxyethyl phosphorus hydroxide, tripropyl-hydroxyethyl phosphorus hydroxide, tributyl-hydroxyethyl phosphorus hydroxide, tributyl-benzyl phosphorus hydroxide, triethyl-benzyl phosphorus hydroxide, tripropyl-benzyl phosphorus hydroxide, N,N,N-triethyl-adamantyl phosphorus chloride, and N,N,N-tripropyl-adamantyl phosphorus chloride.

[0024] Secondly, the present invention provides a method for synthesizing high-silica EMT molecular sieves, comprising the following steps:

[0025] a) Containing aluminum source Al 1 Silicon source Si 1 Alkali metal source M 1 Organic template agent R 1 Mixture I is obtained by mixing raw materials with water, and mixture I is then aged to obtain a directing agent;

[0026] The aluminum source Al in mixture I 1 Silicon source Si 1 Alkali metal source M 1 Organic template agent R 1 It has the following molar ratio with water:

[0027] SiO2 / Al2O3 = 5~30;

[0028] M 1 2O / Al2O3 = 0~7, where M 1 Selected from at least one of the alkali metal elements;

[0029] R 1 / Al2O3=1~40;

[0030] H2O / Al2O3 = 100~600;

[0031] b) Containing aluminum source Al 2 Silicon source Si 2 Alkali metal source M 2 Organic template agent R 2 The raw materials are mixed with water to obtain an initial gel;

[0032] The aluminum source Al in the initial gel 2 Silicon source Si 2 Alkali metal source M 2 Organic template agent R 2 It has the following molar ratio with water:

[0033] SiO2 / Al2O3 = 10~200;

[0034] M 2 2O / Al2O3 = 0~30, where M 2 Selected from at least one of the alkali metal elements;

[0035] R 2 / Al2O3=1~45;

[0036] H2O / Al2O3 = 100~8000;

[0037] c) The directing agent described in step a) is added to the initial gel described in step b) to form a synthetic gel. The synthetic gel is crystallized under closed conditions to obtain a high-silica EMT molecular sieve with an EMT topology.

[0038] Among them, silicon source Si 1 Silicon source Si 2 The molar number is expressed as SiO2;

[0039] Aluminum source Al 1 Aluminum source Al 2 The number of moles is expressed as Al2O3;

[0040] Template agent R 1 Template agent R 2 The number of moles in R 1 R 2 Counted by its own mole count;

[0041] Alkali metal source M 1 The number of moles of its corresponding alkali metal M 1 Metal oxide M 1 2O in moles;

[0042] Alkali metal source M 2 The number of moles of its corresponding alkali metal M 2 Metal oxide M 2 2O moles.

[0043] The present invention proposes a method for synthesizing high-silicon EMT molecular sieves with EMT topology, which promotes the synthesis of high-silicon (silicon-aluminum oxide ratio of 7~30) EMT molecular sieves by adding a directing agent solution to the synthesis gel system and introducing an organic template agent into the synthesis gel system.

[0044] Optionally, the silicon source Si in step a) 1 And the silicon source Si in step b) 2 Each is independently selected from at least one of methyl orthosilicate, ethyl orthosilicate, silica sol, solid silica gel, fumed silica, and sodium silicate;

[0045] The aluminum source Al in step a) 1 And the aluminum source Al in step b) 2 Each is independently selected from at least one of sodium aluminate, alumina, aluminum hydroxide, aluminum isopropoxide, aluminum 2-butoxide, aluminum chloride, aluminum sulfate, aluminum nitrate, and boehmite;

[0046] The alkali metal source M in step a) 1 and the alkali metal source M in step b). 2Each is independently selected from at least one of sodium hydroxide, potassium hydroxide, and cesium hydroxide.

[0047] Optionally, the organic template agent R in step a) 1 and the organic template agent R in step b) 2 Each is independently selected from one of the quaternary phosphorus compounds;

[0048] The structural formula of the quaternary phosphorus compounds is shown in Formula II;

[0049] Formula II;

[0050] Wherein, R in Equation II 21 R 22 R 23 and R 24 Each is independently selected from C1 to C2. 12 Alkyl, C1~C 12 alkoxy groups, C1~C 12 Hydroxyalkyl, aryl, or adamantyl;

[0051] X n- Selected from OH - Cl - ,Br - I - NO3 - HSO4 - H2PO3 - SO4 2- HPO3 2- or PO3 3- .

[0052] Optionally, the "C1~C" 12 "alkyl" includes "C7~C 12 "Phenylalkyl".

[0053] Optionally, the "aryl" includes "C7~C 12 "Aryl".

[0054] Optionally, the "C7~C" 12 "Aryl" includes "C7~C 12 "alkyl aryl".

[0055] Optionally, the organic template agent R in step a) 1 and the organic template agent R in step b) 2Each of the following is independently selected from at least one of tetramethyl phosphorus hydroxide, tetraethyl phosphorus hydroxide, tetrapropyl phosphorus hydroxide, tetrabutyl phosphorus hydroxide, tetrapentyl phosphorus hydroxide, tetrahexyl phosphorus hydroxide, tetrapropyl phosphorus bromide, tetrabutyl phosphorus chloride, tetrapentyl phosphorus bromide, tripropyl-isobutyl phosphorus bromide, tributyl-cyclohexyl phosphorus hydroxide, dibutyl-dihexyl phosphorus hydroxide, choline, triethyl-hydroxyethyl phosphorus hydroxide, tripropyl-hydroxyethyl phosphorus hydroxide, tributyl-hydroxyethyl phosphorus hydroxide, tributyl-benzyl phosphorus hydroxide, triethyl-benzyl phosphorus hydroxide, tripropyl-benzyl phosphorus hydroxide, N,N,N-triethyl-adamantyl phosphorus chloride, and N,N,N-tripropyl-adamantyl phosphorus chloride.

[0056] Optionally, the organic template agent R in step a) 1 Selected from at least one of tetramethylphosphorus hydroxide, tetraethylphosphorus hydroxide, and tetrapropylphosphorus hydroxide;

[0057] The organic template agent R in step b) 2 It is selected from at least one of tetraethyl phosphorus hydroxide, tetrapropyl phosphorus hydroxide, tetrabutyl phosphorus hydroxide, tetrapentyl phosphorus hydroxide, tetrahexyl phosphorus hydroxide, tetrapropyl phosphorus bromide, tetrabutyl phosphorus chloride, tetrapentyl phosphorus bromide, tripropyl-isobutyl phosphorus bromide, tributyl-cyclohexyl phosphorus hydroxide, dibutyl-dihexyl phosphorus hydroxide, choline, triethyl-hydroxyethyl phosphorus hydroxide, tripropyl-hydroxyethyl phosphorus hydroxide, tributyl-hydroxyethyl phosphorus hydroxide, tributyl-benzyl phosphorus hydroxide, triethyl-benzyl phosphorus hydroxide, tripropyl-benzyl phosphorus hydroxide, N,N,N-triethyl-adamantyl phosphorus chloride, and N,N,N-tripropyl-adamantyl phosphorus chloride.

[0058] Optionally, in step a), the aging temperature is 25~140℃, and the aging time is 0.5~30 days.

[0059] Optionally, in step a), the aging is a two-stage aging process. The temperature of the first stage of aging is 30~40℃ and the aging time is 0.5~5 days. The temperature of the second stage of aging is 50~100℃ and the aging time is 2~8 days.

[0060] Optionally, step a) includes: applying aluminum source Al 1 Alkali metal source M 1 Organic template agent R 1 Mix thoroughly with water, then add silicon source S. 1 The mixture is stirred and then aged at a temperature of 25-140℃ for 1-30 days to obtain the directing agent.

[0061] In the preparation of the directing agent, the present invention can induce crystallization through an aging step, thereby promoting the synthesis of high-silica EMT molecular sieves.

[0062] Optionally, in step a), the aging temperature is selected from any value or a range between any two of 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 110°C, 120°C, 130°C, and 140°C.

[0063] Optionally, in step a), the aging time is selected from any value or a range between any two of 0.5 days, 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, 14 days, 15 days, 18 days, 20 days, 25 days, and 30 days.

[0064] Optionally, step a) aging can be carried out by placing the object at rest and / or rotating it.

[0065] Optionally, in step a), the aluminum source Al 1 Silicon source Si 1 Alkali metal source M 1 Organic template agent R 1 It has the following molar ratio with water:

[0066] SiO2 / Al2O3 = 5~30;

[0067] M 1 2O / Al2O3 = 0~5, where M 1 Selected from at least one of the alkali metal elements;

[0068] R 1 / Al2O3=5~40;

[0069] H2O / Al2O3 = 100~600.

[0070] Optionally, in step a), the molar ratio of SiO2 / Al2O3 is selected from any value or a range between any two of 5.0, 6.0, 7.0, 8.0, 9.0, 10, 11, 12, 13, 14, 15, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30.

[0071] Optionally, in step a), the molar ratio of M2O / Al2O3 is selected from any value of 0.1, 0.5, 1.8, 2.0, 3.0, 4.0, 4.5, 4.8 and 5.0 or any range between two.

[0072] Optionally, in step a), R 1The molar ratio of / Al2O3 is selected from any value or a range between any two of the following: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 22, 25, 28, 29, 30, 32, 35, 34, 38, and 40.

[0073] Optionally, the molar ratio of H2O / Al2O3 in step a) is selected from any value or a range between 100, 150, 180, 200, 250, 300, 350, 400, 450, 500, 550 and 600.

[0074] Optionally, step b) includes: applying aluminum source Al 1 Alkali metal source M 1 Organic template agent R 2 Mix thoroughly with water, then add silicon source Si. 2 Add a guiding agent, mix, and obtain the initial gel.

[0075] Optionally, the aluminum source Al mentioned in step b) 2 Silicon source Si 2 Alkali metal source M 2 Organic template agent R 2 It has the following molar ratio with water:

[0076] SiO2 / Al2O3 = 10~200;

[0077] M 2 2O / Al2O3 = 0~30, where M 2 Selected from at least one of the alkali metal elements;

[0078] R 2 / Al2O3=1~45;

[0079] H2O / Al2O3 = 100~6000.

[0080] Optionally, in step b), the molar ratio of SiO2 / Al2O3 is selected from any value or a range between 10, 15, 20, 30, 40, 45, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, and 200.

[0081] Optionally, in step b), the molar ratio of M2O / Al2O3 is selected from any value or a range between any two of 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, and 30.

[0082] Optionally, the molar ratio of R / Al2O3 is selected from any value or a range between any two of the following: 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.

[0083] Optionally, the molar ratio of H2O / Al2O3 is selected from any value or a range between 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.

[0084] Optionally, in step c), the mass ratio of silica in the guiding agent to silica in the initial gel is 0.05~0.3:1.

[0085] Optionally, in step c), the mass ratio of silica in the guiding agent to silica in the initial gel is any one of the following ratios and the range between any two ratios: 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, 0.16:1, 0.15:1, 0.20:1, 0.25:1, and 0.30:1.

[0086] Optionally, in step c), the crystallization temperature is 90~180℃, and the crystallization time is 1~15 days.

[0087] Optionally, the crystallization temperature in step c) is 90~180℃, and the crystallization time is 2~15 days.

[0088] Optionally, the crystallization temperature in step c) is selected from any value or a range between 90°C, 100°C, 110°C, 140°C, 150°C, 160°C and 180°C.

[0089] Optionally, the crystallization time in step c) is selected from any value or a range between 1 day, 2 days, 3 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.

[0090] Optionally, in step c), the crystallization method is dynamic crystallization and / or static crystallization.

[0091] Optionally, the crystallization method described in step c) is rotational crystallization.

[0092] Optionally, in step c), the synthesized gel is crystallized in a sealed reactor at a temperature of 90-140°C for 3-15 days. After crystallization, the resulting solid is separated, washed, and dried to obtain the high-silica EMT molecular sieve with an EMT topology.

[0093] As one specific implementation method, the method includes the following steps:

[0094] a) Containing aluminum source Al 1 Silicon source Si 1 Alkali metal source M 1 Organic template agent R 1 The raw material is mixed with water to obtain mixture I, and mixture I is aged to obtain a directing agent;

[0095] The aluminum source Al in mixture I 1 Silicon source Si 1 Alkali metal source M 1 Organic template agent R 1 It has the following molar ratio with water:

[0096] SiO2 / Al2O3 = 5~30;

[0097] M 1 2O / Al2O3 = 0~5, where M 1 Selected from at least one of the alkali metal elements;

[0098] R 1 / Al2O3=5~40;

[0099] H2O / Al2O3 = 100~600;

[0100] b) Containing aluminum source Al 2 Silicon source Si 2Alkali metal source M 2 Organic template agent R 2 The raw materials are mixed with water to obtain an initial gel;

[0101] The aluminum source Al in the initial gel 2 Silicon source Si 2 Alkali metal source M 2 Organic template agent R 2 Water has the following molar ratio:

[0102] SiO2 / Al2O3 = 10~200;

[0103] M 2 2O / Al2O3 = 0~30, where M 2 Selected from at least one of the alkali metal elements;

[0104] R 2 / Al2O3=1~45;

[0105] H2O / Al2O3 = 100~6000;

[0106] c) Add the directing agent from step a) to the initial gel from step b), mix evenly, and place it in a sealed reaction vessel for crystallization. The crystallization temperature is 90~180℃, and the crystallization time is 2~15 days. After crystallization is completed, the obtained solid is separated, washed, and dried to obtain the high-silica EMT molecular sieve with EMT topology.

[0107] Among them, silicon source Si 1 Si 2 The molar number is expressed in terms of SiO2; aluminum source Al 1 Al 2 The molar number is calculated in terms of Al2O3; template agent R 1 R 2 The number of moles in R 1 R 2 Mole count of itself; Alkali metal source M 1 M 2 The number of moles of its corresponding alkali metal M 1 M 2 The corresponding metal oxide M 1 2O, M 2 20 moles.

[0108] As one specific implementation method, the synthesis process of the high-silica EMT molecular sieve is as follows:

[0109] a) Preparation of directing agents: aluminum source, silicon source, organic template agent R 1 Deionized water was mixed according to the formula: 1Al₂O₃:(5~30)SiO₂:(0~7)M1 2O:(1~40)R 1 A homogeneous mixture was prepared by mixing and stirring H2O at a molar ratio of (100~600) for 2 hours, and then stirring / standing at 25~140℃ for 1~30 days to obtain a directing agent.

[0110] b) Preparation of synthetic gel: aluminum source, silicon source, sodium hydroxide, organic template agent R 2 Mix with deionized water in the following proportions:

[0111] SiO2 / Al2O3 = 10~200;

[0112] M 2 2O / Al2O3 = 0~30, where M 2 Selected from at least one of the alkali metal elements;

[0113] R 2 / Al2O3=1~45;

[0114] H2O / Al2O3 = 100~8000;

[0115] The initial gel was prepared by mixing and stirring at room temperature. Then, a certain amount of the directing agent from step a) was added and stirred for 1 to 4 hours to obtain the synthetic gel.

[0116] c) Synthesis of high-silica EMT molecular sieve: The above-synthesized gel is crystallized at 90~180℃ under autogenous pressure for 2~15 days. After crystallization, the solid product is filtered and separated, washed with deionized water until neutral, and dried to obtain high-silica EMT molecular sieve.

[0117] Thirdly, the present invention provides a catalyst comprising the above-described high-silica EMT molecular sieve or a high-silica EMT molecular sieve with an EMT topology prepared by the above method.

[0118] Fourthly, the present invention provides the application of the above-mentioned high-silica EMT molecular sieve or the high-silica EMT molecular sieve with EMT topology prepared by the above method or the above-mentioned catalyst in the production of high-octane gasoline by isobutane / 2-butene alkylation.

[0119] In this application, C1~C 12 C7~C 12 "Equal" refers to the number of carbon atoms contained. For example, "C1~C1" 12 "Alkyl" refers to an alkyl group containing 1 to 4 carbon atoms.

[0120] In this application, "alkyl" refers to a group formed by losing any one hydrogen atom from an alkane compound molecule. The alkane compound includes straight-chain alkanes, branched alkanes, cycloalkanes, and branched cycloalkanes.

[0121] In this application, "alkoxy group" refers to a group formed by losing a hydrogen atom from the -OH group on an alkyl alcohol molecule. For example, the methoxy group -OCH3 is formed by losing a hydrogen atom from the -OH group on a CH3OH molecule.

[0122] In this application, "hydroxyalkyl" refers to a group formed by losing any hydrogen atom from a non-OH group on an alkyl alcohol molecule. For example, hydroxymethyl HOCH2- is formed by losing a hydrogen atom from the methyl group on a CH3OH molecule.

[0123] In this application, "aryl" is a group formed by the loss of a hydrogen atom from the aromatic ring of an aromatic compound molecule; such as p-tolyl formed by the loss of a hydrogen atom at the para position of the methyl group on the benzene ring of toluene.

[0124] In this application, "alkylphenyl" is a group formed by the loss of a hydrogen atom from a benzene ring containing a substituent; such as p-tolyl formed by the loss of a hydrogen atom at the para-position of the methyl group on the benzene ring of toluene.

[0125] In this application, "benzyl" is a group formed by the loss of any hydrogen atom from an alkyl substituent on a benzene ring; such as benzyl (benzyl) formed by the loss of a hydrogen atom from a methyl group on toluene.

[0126] Compared with the prior art, the present invention has the following beneficial effects:

[0127] 1) This invention synthesizes high-silica EMT molecular sieves with a silicon-aluminum oxide ratio of 7 to 30 by introducing organic template agents and adding directing agents into the synthetic gel.

[0128] 2) The high silica-to-alumina ratio EMT molecular sieve synthesized in this invention 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 practical chemical production. Attached Figure Description

[0129] Figure 1 This is the X-ray diffraction (XRD) pattern of sample EMT1 in Example 1 of this invention;

[0130] Figure 2 This is a scanning electron microscope (SEM) image of sample EMT1 from Example 1 of the present invention;

[0131] Figure 3 The silicon NMR of sample EMT1 in Example 1 of this invention (… 29 Si-NMR spectrum;

[0132] Figure 4 This is the X-ray diffraction (XRD) pattern of sample S1 in Comparative Example 1 of this invention;

[0133] Figure 5 This is the X-ray diffraction (XRD) spectrum of sample T1 in Comparative Example 2 of this invention. Detailed Implementation

[0134] The present application is further illustrated below with reference to specific embodiments. The following descriptions are merely a few embodiments of the present application and are not intended to limit the present application in any way. Although the present application discloses preferred embodiments as follows, they are not intended to limit the present application. Any modifications or variations made by those skilled in the art without departing from the scope of the technical solution of the present application using the disclosed technical content are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

[0135] The analysis method in the embodiments of this application is as follows:

[0136] X-ray powder diffraction (XRD) phase analysis of the products was performed using an X'Pert PRO X-ray diffractometer from PANalEMTtical, Netherlands, with a Cu target, Kα radiation source (λ=0.15418 nm), voltage 40 kV, and current 40 mA.

[0137] The scanning electron microscope (SEM) used for testing was a Hitachi SU8020 field emission scanning electron microscope with an accelerating voltage of 2kV.

[0138] Elemental composition was determined using a Philips Magix 2424 X-ray fluorescence analyzer (XRF).

[0139] Silicon NMR ( 29 Si MAS NMR experiments were conducted on a Bruker Avance III 600 (14.1 Tesla) spectrometer using a 7 mm dual resonance probe at a rotation speed of 8 kHz. A high-power proton decoupling procedure was employed, with 1024 samplings, a π / 4 pulse width of 2.5 μs, and a sampling delay of 10 s. Sodium 4,4-dimethyl-4-propanesulfonate (DSS) was used as the chemical shift reference, and the results were corrected to 0 ppm.

[0140] Carbon NMR (carbon nuclear magnetic resonance) 13 The ¹³C MAS NMR experiment was conducted on a Bruker Avance III 600 (14.1 Tesla) spectrometer using a 4 mm triple resonance probe at a rotation speed of 12 kHz, with adamantane as the chemical shift reference and corrected to 0 ppm.

[0141] Example 1 (Preparation of sample EMT1)

[0142] Preparation of the directing agent: 1.3 g of sodium hydroxide (analytical grade, Tianjin Kemei Chemical Reagent Co., Ltd.) and 1.7 g of alumina (chemically pure, China National Pharmaceutical Group Shanghai Chemical Reagent Co., Ltd.) were dissolved in 84.1 g of tetraethyl phosphorus hydroxide (35 wt% aqueous solution, Aladdin Reagent (Shanghai) Co., Ltd.) and stirred until clear. Then, 34.7 g of tetraethyl orthosilicate (chemically pure, China National Pharmaceutical Group Shanghai Chemical Reagent Co., Ltd.) was added dropwise and stirred for 2 h. The above solution was then aged at 50 °C for 12 h and then aged at 100 °C for 48 h.

[0143] Preparation of synthetic gel: 0.7 g sodium aluminate (Al2O3: 48.3 wt%, Na2O: 36.3 wt%, China National Pharmaceutical Group Shanghai Chemical Reagent Co., Ltd.), 0.20 g sodium hydroxide, and 9.8 g tetrapropylphosphorus hydroxide (25 wt%) were dissolved in 4.8 g deionized water and stirred until clear. 14.7 g silica sol (SiO2: 30 wt%, Shenyang Chemical Co., Ltd.) was added dropwise and stirred for 2 h. Then, 4.9 g of the above-mentioned directing agent was added and stirred for 3 h.

[0144] Synthesis of high-silica EMT molecular sieve: The synthesized gel was transferred into a stainless steel reactor and crystallized at 130℃ for 5 days. After crystallization, the solid and liquid were separated and washed until neutral. The gel was dried at 100℃ for 12 hours and recorded as sample EMT1.

[0145] The X-ray powder diffraction (XRD) pattern of sample 1 is as follows: Figure 1 As shown, sample 1 is a molecular sieve with an EMT framework structure. Scanning electron microscopy (SEM) images are shown below. Figure 2 As shown, sample 1 has a thin sheet structure with a thickness of 50 nm to 100 nm. 29 Si MASNMR spectrum as follows Figure 3 As shown, the fitted calculation of the skeleton silicon-to-aluminum ratio is consistent with that calculated using XRF. Based on XRF and... 13 ¹³C NMR analysis and normalization yielded the following elemental composition for sample 1: 0.07Na·0.02R¹ 2 0.05R2 1 (Si) 0.86 Al 0.14 O2, where R1 2 It is tetraethylphosphorus hydroxide, R2 1 It is tetrapropylphosphorus hydroxide.

[0146] Example 2 (Preparation of samples EMT2~EMT30)

[0147] The mixing process of samples EMT2-EMT30 is the same as that of Example 1. The types of raw materials, molar ratios, crystallization conditions, crystal structure of the products, and silicon-aluminum ratio (the silicon-aluminum ratio of the products is measured by X-ray fluorescence analyzer (XRF)) are shown in Table 1. The aging temperature, time, aging method, amount of directing agent added, and sample composition of samples EMT2-EMT30 are detailed in Table 2.

[0148] Table 1. Raw material types, molar ratios, crystallization conditions, crystal structures, and silicon-to-aluminum ratios of EMT1-EMT30 samples

[0149]

[0150] Note: Al2O3 1 Alumina; SiO2 1 : Silica sol; R1 1 : Tetramethylphosphorus hydroxide; R2 1 Tetrapropylphosphine hydroxide

[0151] Al2O3 2 Aluminum isopropoxide; SiO2 2 : Ethyl orthosilicate; R1 2 : Tetraethylphosphorus hydroxide; R2 2 Triethylhexylphosphine hydroxide

[0152] Al2O3 3 Sodium aluminate; SiO2 3 : Silica; R1 3 : Tetrapropylphosphine hydroxide; R2 3 Triethylbenzylphosphine hydroxide

[0153] Al2O3 4 Aluminum nitrate; SiO2 4 Silicone; R1 4 : Choline; R2 4 : N,N,N-tripropylphosphonic hydroxide Al2O3 5 : Aluminum 2-butoxide; R2 5 Dipropyl dibutylphosphine hydroxide

[0154] Al2O3 6 Aluminum sulfate; R2 6 Benzyltripropylphosphine hydroxide

[0155] Al2O3 7 Aluminum powder; R2 7 Benzyltrimethylphosphine hydroxide

[0156] R28 Tetrabutylphosphine hydroxide R2 9 Tetrahexylphosphine hydroxide

[0157] R2 10 Tributyl-hydroxyethyl phosphorus hydroxide R2 11 Tripropyl-hydroxyethyl phosphorus hydroxide

[0158] Table 2. Aging temperature, time, dosage, and sample composition of EMT1-EMT30 directing agents

[0159]

[0160] Note: R1 1 : Tetramethylphosphorus hydroxide; R2 1 Tetrapropylphosphine hydroxide

[0161] R1 2 : Tetraethylphosphorus hydroxide; R2 2 Triethyl-hexylphosphine hydroxide

[0162] R1 3 : Tetrapropylphosphine hydroxide; R2 3 Triethylbenzylphosphine hydroxide

[0163] R1 4 : Choline; R2 4 : N,N,N-tripropyltrimonium alkylphosphine hydroxide R2 5 Dipropyl-dibutylphosphine hydroxide

[0164] R2 6 Tripropyl-benzylphosphine hydroxide

[0165] R2 7 Benzyltrimethylphosphine hydroxide

[0166] R2 8 Tetrabutylphosphine hydroxide

[0167] R2 9 Tetrahexylphosphine hydroxide

[0168] R2 10 Tributyl-hydroxyethyl phosphorus hydroxide

[0169] R2 11 Tripropyl-hydroxyethyl phosphorus hydroxide

[0170] Comparative Example 1 (Preparation of control samples S1~S30)

[0171] The difference between Comparative Example 1 and Example 1 is that there is no directing agent preparation step in Comparative Example 1, and no directing agent is added in the subsequent gel synthesis steps; the specific raw material types, molar ratios, mixing process and crystallization conditions for synthesizing the gel are the same as those for preparing sample 1# in Example 1; the raw material types, molar ratios, crystallization conditions and crystal structures of each product synthesized in the comparative examples are detailed in Table 3, and the obtained samples are recorded as comparative samples S1~S30.

[0172] Table 3. Raw material type, molar ratio, crystallization conditions, and crystal structure of samples S1-S30

[0173]

[0174] Note: Al2O3 1 Alumina; SiO2 1 : Silica sol; R2 1 Tetrapropylphosphine hydroxide

[0175] Al2O3 2 Aluminum isopropoxide; SiO2 2 : Ethyl orthosilicate; R2 2 Triethyl-hexylphosphine hydroxide

[0176] Al2O3 3 Sodium aluminate; SiO2 3 : Silica; R2 3 Triethyl-benzylphosphine hydroxide

[0177] Al2O3 4 Aluminum nitrate; SiO2 4 Silicone; R2 4 : N,N,N-tripropylphosphonic hydroxide Al2O3 5 : Aluminum 2-butoxide; R2 5 Dipropyl dibutylphosphine hydroxide

[0178] Al2O3 6 Aluminum sulfate; R2 6 Benzyltripropylphosphine hydroxide

[0179] Al2O3 7 Aluminum powder; R2 7 Benzyltrimethylphosphine hydroxide

[0180] R2 8 Tetrabutylphosphine hydroxide R2 9 Tetrahexylphosphine hydroxide

[0181] R2 10 Tributyl-hydroxyethyl phosphorus hydroxide R2 11Tripropyl-hydroxyethyl phosphorus hydroxide

[0182] Comparative Example 2 (Preparation of control samples T1~T30)

[0183] The difference between Comparative Example 2 and Example 1 is that, after the preparation of the directing agent in Comparative Example 2, the mixture was stirred at room temperature for 2 hours without aging; the specific types of raw materials, molar ratios, mixing process, and crystallization conditions were the same as those for the preparation of sample EMT1 in Example 1; the types of raw materials, molar ratios, crystallization conditions, amount of directing agent added, and crystal structure of each product synthesized in Comparative Example 2 are detailed in Table 4. The obtained samples are designated as comparative samples T1 to T30.

[0184] Table 4. Raw material types, amount of directing agent added, molar ratio, crystallization conditions and crystal structure of samples T1~T30

[0185]

[0186] Note: Al2O3 1 Alumina; SiO2 1 : Silica sol; R1 1 : Tetramethylphosphorus hydroxide; R2 1 Tetrapropylphosphine hydroxide

[0187] Al2O3 2 Aluminum isopropoxide; SiO2 2 : Ethyl orthosilicate; R1 2 : Tetraethylphosphorus hydroxide; R2 2 Triethylhexylphosphine hydroxide

[0188] Al2O3 3 Sodium aluminate; SiO2 3 : Silica; R1 3 : Tetrapropylphosphine hydroxide; R2 3 Triethylbenzylphosphine hydroxide

[0189] Al2O3 4 Aluminum nitrate; SiO2 4 Silicone; R1 4 : Choline; R2 4 : N,N,N-tripropylphosphonic hydroxide Al2O3 5 : Aluminum 2-butoxide; R2 5 Dipropyl dibutylphosphine hydroxide

[0190] Al2O3 6 Aluminum sulfate; R2 6 Benzyltripropylphosphine hydroxide

[0191] Al2O37 Aluminum powder; R2 7 :choline

[0192] R2 8 Tetrabutylphosphine hydroxide

[0193] R2 9 Tetrahexylphosphine hydroxide

[0194] R2 10 Tributyl-hydroxyethyl phosphorus hydroxide

[0195] R2 11 Tripropyl-hydroxyethyl phosphorus hydroxide

[0196] Example 3 (Characteristic analysis of samples EMT1~EMT30 and control samples S1, T1)

[0197] X-ray diffraction was used to analyze the phase composition of samples EMT1~EMT30 and control samples S1~S30 and T1~T30.

[0198] The results showed that the samples EMT1~EMT30 prepared in Examples 1 and 2 were all high-purity and highly crystallinity EMT-type molecular sieves, with typical examples as follows: Figure 1 XRD pattern of sample EMT1 Figure 2 Here is the SEM image of EMT1. Figure 3 The silicon NMR of sample EMT1. The XRD patterns of samples EMT2-EMT30 are shown below. Figure 1 The diffraction peaks are close, meaning that their positions and shapes are basically the same. The relative peak intensities fluctuate within ±5% depending on the synthesis conditions, indicating that samples EMT1-EMT30 have the structural characteristics of EMT-type molecular sieves and are free of impurities.

[0199] In Tables 3 and 4, both comparative samples S1-S30 and T1-T30 are amorphous. The XRD patterns of comparative samples S1 and T1 are shown below. Figure 4 and Figure 5 As shown.

[0200] The above comparison shows that the addition of a directing agent is essential in the synthesis of high-silica EMT molecular sieves, and the directing agent must be aged at high temperature during preparation in order to induce crystallization. This is the key to the synthesis of high-silica EMT molecular sieves.

[0201] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A high-silica EMT molecular sieve, characterized in that, The anhydrous chemical structural formula of the high-silica EMT molecular sieve is Formula I: kM·mR 1 ·nR 2 ·(Si x Al y )O2 formula I; Wherein, M is selected from at least one alkali metal element; R 1 R 2 It is an organic template agent; R 1 R 2 Each is independently selected from one of the quaternary phosphorus compounds; The structural formula of the quaternary phosphorus compound is Formula II: Formula II; In Equation II, R 21 R 22 R 23 and R 24 Each is independently selected from C1 to C2. 12 Alkyl, C1~C 12 alkoxy groups, C1~C 12 hydroxyalkyl, C7~C 12 Benzenealkyl, C7~C 12 Alkylphenyl or adamantyl; X n- Selected from OH - Cl - ,Br - I - NO3 - HSO4 - H2PO3 - SO4 2- HPO3 2- or PO3 3- ; k is the number of moles (Si) x Al y The number of moles of the alkali metal element M corresponding to O2, k = 0~0.20; m and n are respectively per mole (Si) x Al y O2 corresponds to the template agent R 1 R 2 The number of moles, m = 0.01~0.20, n = 0.01~0.20; x and y are the mole fractions of Si and Al, respectively, 2x / y = 7~40, and x+y = 1. Furthermore, the high-silica EMT molecular sieve is synthesized by a method comprising the following steps: a) Containing aluminum source Al 1 Silicon source Si 1 Alkali metal source M 1 Organic template agent R 1 Mixture I is obtained by mixing raw materials with water, and mixture I is then aged to obtain a directing agent; The aluminum source Al in mixture I 1 Silicon source Si 1 Alkali metal source M 1 Organic template agent R 1 It has the following molar ratio with water: SiO2 / Al2O3 = 5~30; M 1 2O / Al2O3 = 0~7, where M 1 Selected from at least one of the alkali metal elements; R 1 Al2O3 = 1~40; H2O / Al2O3 = 100~600; b) Containing aluminum source Al 2 Silicon source Si 2 Alkali metal source M 2 Organic template agent R 2 The raw materials are mixed with water to obtain an initial gel; The aluminum source Al in the initial gel 2 Silicon source Si 2 Alkali metal source M 2 Organic template agent R 2 It has the following molar ratio with water: SiO2 / Al2O3 = 10~200; M 2 2O / Al2O3 = 0~30, where M 2 Selected from at least one of the alkali metal elements; R 2 Al2O3 = 1~45; H2O / Al2O3 = 100~8000; c) The directing agent described in step a) is added to the initial gel described in step b) to form a synthetic gel. The synthetic gel is crystallized under closed conditions to obtain a high-silica EMT molecular sieve with an EMT topology. Among them, silicon source Si 1 Silicon source Si 2 The molar number is expressed as SiO2; Aluminum source Al 1 Aluminum source Al 2 The number of moles is expressed as Al2O3; Template agent R 1 Template agent R 2 The number of moles in R 1 R 2 Counted by its own mole count; Alkali metal source M 1 The number of moles of its corresponding alkali metal M 1 Metal oxide M 1 2O in moles; Alkali metal source M 2 The number of moles of its corresponding alkali metal M 2 Metal oxide M 2 2O moles.

2. The high-silica EMT molecular sieve according to claim 1, characterized in that, In Formula I, M is selected from at least one of Na, K, and Cs; 2x / y = 8~30.

3. The high-silica EMT molecular sieve according to claim 2, characterized in that, The high-silica EMT molecular sieve has an EMT topology, and the silicon-aluminum oxide ratio of the molecular sieve is 7~30.

4. The high-silica EMT molecular sieve according to claim 2, characterized in that, R in Equation I 1 R 2 Each of the following is independently selected from at least one of tetramethyl phosphorus hydroxide, tetraethyl phosphorus hydroxide, tetrapropyl phosphorus hydroxide, tetrabutyl phosphorus hydroxide, tetrapentyl phosphorus hydroxide, tetrahexyl phosphorus hydroxide, tetrapropyl phosphorus bromide, tetrabutyl phosphorus chloride, tetrapentyl phosphorus bromide, tripropyl-isobutyl phosphorus bromide, tributyl-cyclohexyl phosphorus hydroxide, dibutyl-dihexyl phosphorus hydroxide, choline, triethyl-hydroxyethyl phosphorus hydroxide, tripropyl-hydroxyethyl phosphorus hydroxide, tributyl-hydroxyethyl phosphorus hydroxide, tributyl-benzyl phosphorus hydroxide, triethyl-benzyl phosphorus hydroxide, tripropyl-benzyl phosphorus hydroxide, N,N,N-triethyl-adamantyl phosphorus chloride, and N,N,N-tripropyl-adamantyl phosphorus chloride.

5. The high-silica EMT molecular sieve according to claim 1, characterized in that, The organic template agent R in step a) 1 and the organic template agent R in step b) 2 Each of the following is independently selected from at least one of tetramethyl phosphorus hydroxide, tetraethyl phosphorus hydroxide, tetrapropyl phosphorus hydroxide, tetrabutyl phosphorus hydroxide, tetrapentyl phosphorus hydroxide, tetrahexyl phosphorus hydroxide, tetrapropyl phosphorus bromide, tetrabutyl phosphorus chloride, tetrapentyl phosphorus bromide, tripropyl-isobutyl phosphorus bromide, tributyl-cyclohexyl phosphorus hydroxide, dibutyl-dihexyl phosphorus hydroxide, choline, triethyl-hydroxyethyl phosphorus hydroxide, tripropyl-hydroxyethyl phosphorus hydroxide, tributyl-hydroxyethyl phosphorus hydroxide, tributyl-benzyl phosphorus hydroxide, triethyl-benzyl phosphorus hydroxide, tripropyl-benzyl phosphorus hydroxide, N,N,N-triethyl-adamantyl phosphorus chloride, and N,N,N-tripropyl-adamantyl phosphorus chloride.

6. The high-silica EMT molecular sieve according to claim 1, characterized in that, The organic template agent R in step a) 1 Selected from at least one of tetramethylphosphorus hydroxide, tetraethylphosphorus hydroxide, and tetrapropylphosphorus hydroxide; The organic template agent R in step b) 2 It is selected from at least one of tetraethyl phosphorus hydroxide, tetrapropyl phosphorus hydroxide, tetrabutyl phosphorus hydroxide, tetrapentyl phosphorus hydroxide, tetrahexyl phosphorus hydroxide, tetrapropyl phosphorus bromide, tetrabutyl phosphorus chloride, tetrapentyl phosphorus bromide, tripropyl-isobutyl phosphorus bromide, tributyl-cyclohexyl phosphorus hydroxide, dibutyl-dihexyl phosphorus hydroxide, choline, triethyl-hydroxyethyl phosphorus hydroxide, tripropyl-hydroxyethyl phosphorus hydroxide, tributyl-hydroxyethyl phosphorus hydroxide, tributyl-benzyl phosphorus hydroxide, triethyl-benzyl phosphorus hydroxide, tripropyl-benzyl phosphorus hydroxide, N,N,N-triethyl-adamantyl phosphorus chloride, and N,N,N-tripropyl-adamantyl phosphorus chloride.

7. The high-silica EMT molecular sieve according to claim 1, characterized in that, In step a), the aging temperature is 25~140℃ and the aging time is 0.5~30 days.

8. The high-silica EMT molecular sieve according to claim 7, characterized in that, In step a), the aging process consists of two stages: the temperature of the first stage is 30-40℃ and the aging time is 0.5-5 days; the temperature of the second stage is 50-100℃ and the aging time is 2-8 days.

9. The high-silica EMT molecular sieve according to claim 7, characterized in that, Step a) includes: applying aluminum source Al 1 Alkali metal source M 1 Organic template agent R 1 Mix thoroughly with water, then add silicon source S. 1 The mixture is stirred and then aged at a temperature of 25-140℃ for 1-30 days to obtain the directing agent.

10. The high-silica EMT molecular sieve according to claim 7, characterized in that, In step b), the aluminum source Al 2 Silicon source Si 2 Alkali metal source M 2 Organic template agent R 2 It has the following molar ratio with water: SiO2 / Al2O3 = 10~200; M 2 2O / Al2O3 = 0~30, where M 2 Selected from at least one of the alkali metal elements; R 2 Al2O3 = 1~45; H2O / Al2O3 = 100~6000.

11. The high-silica EMT molecular sieve according to claim 1, characterized in that, In step c), the mass ratio of silica in the guiding agent to silica in the initial gel is 0.05~0.3:

1.

12. The high-silica EMT molecular sieve according to claim 11, characterized in that, In step c), the crystallization temperature is 90~180℃, and the crystallization time is 1~15 days.

13. The high-silica EMT molecular sieve according to claim 11, characterized in that, In step c), the crystallization method is dynamic crystallization and / or static crystallization.

14. The application of the high-silica EMT molecular sieve according to any one of claims 1 to 13 in the production of high-octane gasoline by isobutane / 2-butene alkylation.

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