CN115784255B - Preparation method and application of SSZ-74 molecular sieve - Google Patents
Preparation method and application of SSZ-74 molecular sieve Download PDFInfo
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- 239000002808 molecular sieve Substances 0.000 title claims abstract description 214
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 title claims abstract description 214
- 238000002360 preparation method Methods 0.000 title claims abstract description 42
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 106
- 239000010703 silicon Substances 0.000 claims abstract description 106
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 97
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 87
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 82
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 67
- 239000000203 mixture Substances 0.000 claims abstract description 62
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 29
- 239000003513 alkali Substances 0.000 claims abstract description 25
- 238000006243 chemical reaction Methods 0.000 claims abstract description 25
- 238000002156 mixing Methods 0.000 claims abstract description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 132
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 120
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 86
- 239000013078 crystal Substances 0.000 claims description 74
- 238000002425 crystallisation Methods 0.000 claims description 71
- 230000008025 crystallization Effects 0.000 claims description 69
- 239000000377 silicon dioxide Substances 0.000 claims description 62
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 52
- 239000000499 gel Substances 0.000 claims description 44
- 239000007787 solid Substances 0.000 claims description 27
- AMCFBNLEJANOEC-UHFFFAOYSA-N n,n-dimethylethanamine;hydrate Chemical compound [OH-].CC[NH+](C)C AMCFBNLEJANOEC-UHFFFAOYSA-N 0.000 claims description 22
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 claims description 22
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 20
- 229910052708 sodium Inorganic materials 0.000 claims description 20
- 239000011734 sodium Substances 0.000 claims description 20
- 238000000034 method Methods 0.000 claims description 17
- 230000015572 biosynthetic process Effects 0.000 claims description 14
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 claims description 12
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 12
- CQWWONKCVFKXRE-UHFFFAOYSA-N n,n-dimethylethanamine;hydrobromide Chemical compound [Br-].CC[NH+](C)C CQWWONKCVFKXRE-UHFFFAOYSA-N 0.000 claims description 10
- CPRMKOQKXYSDML-UHFFFAOYSA-M rubidium hydroxide Chemical compound [OH-].[Rb+] CPRMKOQKXYSDML-UHFFFAOYSA-M 0.000 claims description 8
- 238000003786 synthesis reaction Methods 0.000 claims description 7
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 6
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 claims description 6
- LFQCEHFDDXELDD-UHFFFAOYSA-N tetramethyl orthosilicate Chemical compound CO[Si](OC)(OC)OC LFQCEHFDDXELDD-UHFFFAOYSA-N 0.000 claims description 6
- MFGOFGRYDNHJTA-UHFFFAOYSA-N 2-amino-1-(2-fluorophenyl)ethanol Chemical compound NCC(O)C1=CC=CC=C1F MFGOFGRYDNHJTA-UHFFFAOYSA-N 0.000 claims description 4
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 claims description 4
- SMZOGRDCAXLAAR-UHFFFAOYSA-N aluminium isopropoxide Chemical compound [Al+3].CC(C)[O-].CC(C)[O-].CC(C)[O-] SMZOGRDCAXLAAR-UHFFFAOYSA-N 0.000 claims description 4
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 claims description 4
- VXAUWWUXCIMFIM-UHFFFAOYSA-M aluminum;oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Al+3] VXAUWWUXCIMFIM-UHFFFAOYSA-M 0.000 claims description 4
- HUCVOHYBFXVBRW-UHFFFAOYSA-M caesium hydroxide Inorganic materials [OH-].[Cs+] HUCVOHYBFXVBRW-UHFFFAOYSA-M 0.000 claims description 4
- 239000006229 carbon black Substances 0.000 claims description 4
- 239000000741 silica gel Substances 0.000 claims description 4
- 229910002027 silica gel Inorganic materials 0.000 claims description 4
- 239000003054 catalyst Substances 0.000 claims description 3
- 150000001336 alkenes Chemical class 0.000 claims description 2
- 238000003756 stirring Methods 0.000 claims description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims 1
- CSDREXVUYHZDNP-UHFFFAOYSA-N alumanylidynesilicon Chemical compound [Al].[Si] CSDREXVUYHZDNP-UHFFFAOYSA-N 0.000 abstract description 11
- 239000002105 nanoparticle Substances 0.000 abstract description 5
- 239000002135 nanosheet Substances 0.000 abstract description 2
- 238000000634 powder X-ray diffraction Methods 0.000 description 37
- 238000012512 characterization method Methods 0.000 description 35
- 239000002585 base Substances 0.000 description 24
- 229910052593 corundum Inorganic materials 0.000 description 21
- 229910001845 yogo sapphire Inorganic materials 0.000 description 21
- 239000000843 powder Substances 0.000 description 20
- 230000000052 comparative effect Effects 0.000 description 18
- 238000001035 drying Methods 0.000 description 17
- 238000005406 washing Methods 0.000 description 16
- 238000001816 cooling Methods 0.000 description 14
- 238000001914 filtration Methods 0.000 description 14
- 229910021536 Zeolite Inorganic materials 0.000 description 6
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 6
- 239000010457 zeolite Substances 0.000 description 6
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 5
- 229910052731 fluorine Inorganic materials 0.000 description 5
- 239000011737 fluorine Substances 0.000 description 5
- -1 methylpyrrolidine ammonium hydroxide Chemical compound 0.000 description 4
- 238000001144 powder X-ray diffraction data Methods 0.000 description 4
- 238000001228 spectrum Methods 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 125000000719 pyrrolidinyl group Chemical group 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 238000001179 sorption measurement Methods 0.000 description 3
- 238000005481 NMR spectroscopy Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000002064 nanoplatelet Substances 0.000 description 2
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 238000005160 1H NMR spectroscopy Methods 0.000 description 1
- 229910004283 SiO 4 Inorganic materials 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 125000003277 amino group Chemical group 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011973 solid acid Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
Landscapes
- Silicates, Zeolites, And Molecular Sieves (AREA)
Abstract
The invention discloses a preparation method and application of an SSZ-74 molecular sieve. The preparation method comprises the following steps: 1) Mixing a silicon source, an aluminum source, a template agent, alkali and water to obtain a gel mixture; 2) Crystallizing the gel mixture in a sealed reaction kettle to obtain the SSZ-74 molecular sieve. The SSZ-74 molecular sieve prepared by the preparation method has a larger adjustable range of silicon-aluminum ratio, has a nano-sheet or nano-particle morphology, and has a wider application space.
Description
Technical Field
The invention belongs to the technical field of molecular sieves, and particularly relates to a preparation method and application of an SSZ-74 molecular sieve.
Background
In 2008, the Chevron company invents a silicon-aluminum molecular sieve (SSZ-74 molecular sieve for short, with the structural code of-SVR) with ordered silicon hydroxyl groups and ten-membered ring pore channels. The SVR molecular sieve is a crystal network structure formed by AlO 4 and SiO 4 tetrahedra, and pore channels in the crystal generate acidity due to substitution of Al 3+ for Si 4+. In the silicon-aluminum molecular sieve, the SVR structure molecular sieve has good thermal stability and hydrothermal stability, moderate acidity, higher specific surface area, highly ordered micropore channels and ordered silicon hydroxyl existing in the channels, and becomes a porous material with wide application prospect in the modern petroleum processing industry, gas adsorption and separation industry.
However, the report on the synthetic preparation method of the molecular sieve with the-SVR structure is very rare, and the chedducton company uses hexamethylene-1, 6-bis (methylpyrrolidine ammonium hydroxide) (Baerlocher, C., xie, D., mcCusker, L.et al. Nature Mater 7,631-635 (2008)) as a template agent in the invention of the high-silicon-SVR molecular sieve, and the follow-up research report shows that the use of asymmetric hexamethylene-1-methyl-1- [ 6-trimethylammonium ] pyrrolidinyl ammonium hydroxide as the template agent can also lead to the synthesis of the pure silicon-SVR zeolite. However, the templating agent suitable for the synthesis of molecular sieves of the-SVR structure is expensive, and in addition, the preparation of SSZ-74 molecular sieves using hexamethylene1, 6-bis (methylpyrrolidinone ammonium hydroxide) and hexamethylene1-methyl-1- [ 6-trimethylammonium ] pyrrolidinylammonium hydroxide as templates is required to be carried out in a fluorine system, but the fluorine system has a safety hazard, and the existing method can only prepare high-silicon or pure-silicon-SVR zeolite, but the silicon-aluminum ratio can only reach 40 at the minimum.
Therefore, the preparation cost is reduced, the synthesis step is simplified, and the development of a novel method capable of simply preparing the-SVR molecular sieve with larger silicon-aluminum ratio range has important practical significance.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, the present invention aims to provide a preparation method and application of an SSZ-74 molecular sieve, so as to solve the problems that a fluorine system is required and the silicon-aluminum ratio range is small in the preparation of the SSZ-74 molecular sieve in the prior art.
In order to achieve the above purpose, the present invention adopts the following technical scheme.
The first aspect of the invention provides a method for preparing an SSZ-74 molecular sieve, comprising the following steps:
1) Mixing a silicon source, an aluminum source, a template agent, alkali and water to obtain a gel mixture;
2) Crystallizing the gel mixture in a sealed reaction kettle to obtain the SSZ-74 molecular sieve.
In certain embodiments, the templating agent is selected from one or both of hexamethylene-1, 6-bis (dimethylethylammonium bromide) and hexamethylene-1, 6-bis (dimethylethylammonium hydroxide).
In certain embodiments, the templating agent may be hexamethylene-1, 6-bis (dimethylethyl ammonium bromide) or a mixture of hexamethylene-1, 6-bis (dimethylethyl ammonium bromide) and hexamethylene-1, 6-bis (dimethylethyl ammonium hydroxide).
In certain more specific embodiments, the templating agent is a mixture of hexamethylene-1, 6-bis (dimethylethyl ammonium bromide) and hexamethylene-1, 6-bis (dimethylethyl ammonium hydroxide).
Preferably, the molar ratio of the hexamethylene-1, 6-bis (dimethylethylammonium bromide) to the hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) is (0.01-1): 0.1. more preferably, the molar ratio may be (0.01 to 0.2): 0.1, or (0.1 to 0.6): 0.1, or (0.4 to 1): 0.1. in certain preferred embodiments, it may also be 0.3:0.1, 0.4:0.1, 0.5:0.1, 0.2:0.1, 0.1:0.1.
In certain embodiments, the templating agent and water are mixed to form an aqueous solution of the templating agent, which is mixed with the aluminum source, the templating agent, and the base.
In certain embodiments, the mass of the silicon source is scaled to obtain the moles of SiO 2 as moles of elemental silicon; converting the mass of the silicon source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of the silicon source to the aluminum source to the alkali to the template agent to the water is 1: (0-0.05): (0.05-0.3): (0.2-0.6): (5-100).
Preferably, the molar ratio of the silicon source, the aluminum source, the base, the templating agent and the water is 1: (0-0.01): (0-0.3): (0.2-0.4): (5 to 100), may be 1: (0.015-0.025): (0.1-2): (0.3-0.5): (5 to 100), may be 1: (0.02-0.05): (0-0.3): (0.3-0.6): (5-100). In certain preferred embodiments, the molar ratio of silicon source, aluminum source, base, templating agent, and water is 1.0：0.005：0.15：0.4：40、1.0：0.0167：0.15：0.4：40、1.8：0.005：0.1：0.4：40、1.0：0.01：0.1：0.4：40、1.0：0.01：0.2：0.4：40、1.0：0.01：0.05：0.4：40 and 1.0:0.02:0.1:0.4:10.
The application is characterized in that the high concentration condition and the low concentration condition are 1.0:0.01:0.1:0.4:10 and 1.0:0.01:0.1:0.4:50 to obtain pure SSZ-74 molecular sieve. In the application, high concentration refers to the mole ratio of silicon source, aluminum source, alkali, template agent and water, wherein the mole ratio of water is lower than 10; in the present application, low concentration means that the molar ratio of the silicon source, the aluminum source, the base, the template agent and water is higher than 50.
The concentration of the templating agent in the present application cannot be too high nor too low. Template ratio is too high, for example SiO 2：Al2O3：NaOH：R：H2 o=1.0: 0.005:0.1:0.6:40, which results in the formation of a lamellar phase; whereas the template ratio is too low, for example SiO 2：Al2O3：NaOH：R：H2 o=1.0: 0.005:0.1:0.05:40, which can result in the formation of other molecular sieves, such as ZSM-12 zeolite.
The crystallization in the application can synthesize the SSZ-74 molecular sieve under high-rotation stirring and static state.
The SSZ-74 molecular sieve can be synthesized without adding seed crystal and aluminum source. SiO 2：NaOH：R：H2 o=1.0: 0.01:0.1:0.4:40.
The ratio of water to silicon in the present application cannot be too high or too low, and too high a ratio of water to silicon (e.g., siO 2：Al2O3：NaOH：R：H2 o=1.0:0.005:0.1:0.05:110) would result in failure to form molecular sieves.
The silicon to aluminum ratio in the present application should not be too high nor too low, and too low a silicon to aluminum ratio (SiO 2：Al2O3：NaOH：R：H2 o=1.0:0.005:0.1:0.4:40) would result in the formation of a heterogeneous molecular sieve.
In certain embodiments, in 2), the sealed reaction vessel further comprises a seed crystal.
Preferably, the seed crystals are selected from SSZ-74 molecular sieve seed crystals. The SSZ-74 molecular sieve seed crystal can be prepared by a method reported in the prior art, can also be obtained by the preparation method of the application, and can also be obtained by a commercial purchase channel. The SSZ-74 molecular sieve seed crystal can be a completely crystallized dry-SVR structure molecular sieve containing the template agent, or can be a completely crystallized dry-SVR structure molecular sieve containing the template agent, and the template agent is removed by high-temperature roasting.
Preferably, the seed crystal is added in an amount of 0.001 to 60% of the solid content of the gel mixture based on the solid content of the gel mixture.
Preferably, the seed crystal may be added in an amount of 0% to 10%, 5% to 15%, 10% to 20%, 15% to 25%, 20% to 30%, 25% to 35%, 30% to 40%, 35% to 45%, 40% to 50%, 45% to 55%, or 50% to 60% of the solid content of the gel mixture. In certain preferred embodiments, 5%, 10%.
In certain embodiments, the silicon source is selected from one or more of white carbon black, silica sol, tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), and silica gel.
Preferably, the silicon source is selected from the group consisting of silica sols.
In certain embodiments, the aluminum source is selected from one or more of pseudoboehmite, alumina, aluminum hydroxide, sodium metaaluminate, aluminum sulfate, aluminum isopropoxide, and aluminum metal.
Preferably, the aluminium source is selected from sodium metaaluminate.
Preferably, the metallic aluminum is selected from one or more of aluminum powder, aluminum dust and aluminum flakes.
In certain embodiments, the base is selected from one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide solids, or an aqueous solution.
Preferably, the base is selected from sodium hydroxide.
In certain embodiments, the crystallization temperature is 120 to 240 ℃.
Preferably, the crystallization temperature may be 120 to 160 ℃, 140 to 180 ℃, 160 to 200 ℃, 180 to 220 ℃ or 200 to 240 ℃. In certain preferred embodiments, 140 ℃, 160 ℃, 180 ℃. In the application, the crystallization temperature cannot be too high or too low, and the template agent is decomposed to form the heterogeneous zeolite; too low (e.g., 100 ℃) results in the formation of amorphous powders that fail to form molecular sieves.
In certain embodiments, the crystallization time is 24 to 336 hours.
Preferably, the crystallization time may be 24 to 100 hours, 96 to 168 hours, 154 to 236 hours, or 268 to 336 hours. In certain preferred embodiments, 168h, 96h. The crystallization time in the application cannot be too short or too long, and if too long, a compact phase with a non-porous structure can be formed, so that the molecular sieve has shape selectivity and selectivity loss; too short (e.g., 24 h) results in the formation of amorphous powder that does not form the molecular sieve.
In certain embodiments, the post-crystallization further comprises a post-treatment comprising washing, drying, and calcining. The washing, drying and roasting are conventional technical means in the field. The drying temperature is 50-130 ℃, and the roasting temperature is 500-600 ℃.
The second aspect of the present invention protects the SSZ-74 molecular sieve obtained by the preparation process as described above.
In certain embodiments, the SSZ-74 molecular sieve has a silica to alumina ratio of not less than 15.
Preferably, the SSZ-74 molecular sieve has a silica to alumina ratio of not less than 50. More preferably 50 to 100. In a preferred embodiment, 50, 100.
In certain embodiments, the SSZ-74 molecular sieve has a microporous structure, the micropores having a diameter of no greater than 1 nm.
Preferably 0.3 to 0.5 nm.
In certain embodiments, the SSZ-74 molecular sieve has a structure of-SVR, a morphology of nanoplatelets or nanoparticles, and a size of 30 nm to 5 microns.
A third aspect of the invention protects the use of an SSZ-74 molecular sieve as described above as a catalyst in a chemical reaction.
In certain embodiments, the chemical reaction comprises methanol to olefins, synthesis gas conversion, and fischer-tropsch synthesis.
Compared with the prior art, the invention has the following beneficial effects:
1) According to the application, the hexamethylene-1, 6-bis (dimethyl ethyl ammonium bromide) or the hexamethylene-1, 6-bis (dimethyl ethyl ammonium hydroxide) containing small molecular organic amino groups is used as the template agent, and compared with the template agent containing pyrrolidinyl groups, the template agent disclosed by the application is easier to prepare and obtain the SSZ-74 molecular sieve, has lower cost and higher safety, and is beneficial to large-scale and industrialized production of the SSZ-74 molecular sieve.
2) The SSZ-74 molecular sieve prepared by the method has a larger adjustable range of silicon-aluminum ratio, the silicon-aluminum ratio is not lower than 15, the high aluminum content can improve the solid acid content in the SSZ-74 molecular sieve, and the SSZ-74 molecular sieve has a nano-sheet or nano-particle morphology, and compared with the high silicon or pure silicon SSZ-74 molecular sieve in the prior art, the high silicon-aluminum ratio is beneficial to expanding the application of the catalyst, so that the SSZ-74 molecular sieve has a wider application space.
3) The SSZ-74 molecular sieve prepared by the method is expected to show unique performance advantages in the fields of petrochemical industry, adsorption separation and the like in industry due to the simultaneous existence of ordered silicon hydroxyl groups and acid aluminum sites in a framework.
Drawings
FIG. 1 shows PXRD spectra and SEM pictures of SSZ-74 molecular sieve crystals obtained in example 1 of the present invention.
FIG. 2 shows the PXRD pattern and SEM photograph of SSZ-74 molecular sieve crystals obtained in example 2 of the present invention.
FIG. 3 shows PXRD spectra and SEM pictures of SSZ-74 molecular sieve crystals obtained in example 3 of the present invention.
FIG. 4 shows the PXRD pattern of the ZSM-12 molecular sieve crystals obtained in comparative example 1 of the invention.
Fig. 5 shows a PXRD pattern of the lamellar phase obtained in comparative example 2 of the present invention.
FIG. 6 shows the H-NMR nuclear magnetic spectrum of SSZ-74 molecular sieve crystals obtained in example 1 of the present invention.
FIG. 7 shows an Al-NMR nuclear magnetic spectrum of SSZ-74 molecular sieve crystals obtained in example 1 of the present invention.
Detailed Description
Further advantages and effects of the present invention will become apparent to those skilled in the art from the disclosure of the present invention, which is described by the following specific examples.
Before the embodiments of the invention are explained in further detail, it is to be understood that the invention is not limited in its scope to the particular embodiments described below; it is also to be understood that the terminology used in the examples of the invention is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the invention. The test methods in the following examples, in which specific conditions are not noted, are generally conducted under conventional conditions or under conditions recommended by the respective manufacturers.
Where numerical ranges are provided in the examples, it is understood that unless otherwise stated herein, both endpoints of each numerical range and any number between the two endpoints are significant both in the numerical range. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition to the specific methods, devices, materials used in the embodiments, any methods, devices, and materials of the prior art similar or equivalent to those described in the embodiments of the present invention may be used to practice the present invention according to the knowledge of one skilled in the art and the description of the present invention.
The inventor discovers that a small molecular organic amino template agent, such as hexamethylene-1, 6-bis (dimethyl ethyl ammonium bromide) or hexamethylene-1, 6-bis (dimethyl ethyl ammonium hydroxide), is adopted as the template agent, and the SSZ-74 molecular sieve with adjustable silicon-aluminum ratio range can be obtained through a one-step crystallization method under an alkaline system. The traditional pyrrolidinyl template can only be synthesized under a fluorine system, and the fluorine system can cause larger crystal size, serious burn and even death, so that the possibility of industrial application of the application is greatly improved, and meanwhile, compared with the pyrrolidinyl template, the cost of the small molecular organic amino template used by the application is lower. The preparation method provided by the application is simple, low in cost and high in safety, and the obtained SSZ-74 molecular sieve is high in crystallinity.
In the present invention, the molecular sieve (referred to as a single crystal) has a native crystal morphology of the nanoplatelets or nanoparticles when viewed using a Scanning Electron Microscope (SEM). The crystal morphology herein refers to the external shape exhibited by a single molecular sieve crystal in the field of view of the scanning electron microscope. The term "as-grown" means a structure which is objectively and directly represented by a molecular sieve after production, and is not a structure which is represented by a molecular sieve after production and then subjected to artificial treatment.
In this example, PXRD data was measured using a bruck D8 advanced X-ray diffractometer, germany, for characterization of the crystal structure of molecular sieves; SEM pictures were obtained from a JEOL 7800Prime field emission scanning electron microscope, japan, for characterizing molecular sieve morphology.
In the examples described below, the templating agent was an aqueous solution of the templating agent at a concentration of 1.0mmol/g based on the total mass of water and templating agent.
The technical scheme of the invention is further described below through specific examples.
Example 1
In this example 1, a SSZ-74 molecular sieve having a silica to alumina ratio of 100 was prepared by adding seed crystals, comprising the following:
1) Silica sol (40 wt% SiO 2), sodium metaaluminate, sodium hydroxide solid powder and hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) are respectively used as a silicon source, an aluminum source, alkali and a template agent to be mixed, and the mixture is stirred at room temperature for overnight to obtain a gel mixture. Wherein, the mole number of SiO 2 is obtained by converting the mass of a silicon source according to the mole number of silicon element; converting the mass of an aluminum source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of silicon source, aluminum source, base, templating agent, and water (SiO 2：Al2O3：NaOH：R：H2 o=1.0:0.005:0.15:0.4:40) was 1.0:0.005:0.15:0.4:40.
2) Adding SSZ-74 molecular sieve seed crystal, transferring to a reaction kettle for crystallization, cooling, filtering, washing, drying at 80 ℃ and roasting at 550 ℃ to obtain the SSZ-74 molecular sieve. Wherein, SSZ-74 molecular sieve seed crystal is obtained through commercial purchase, and the adding amount of the seed crystal is 5% of the solid content of the gel mixture based on the solid content of the gel mixture, and the crystallization conditions are as follows: crystallizing at 160 deg.c for 168 hr at 30rpm.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 100.
The resulting SSZ-74 molecular sieves were characterized by PXRD and SEM, and the results are shown in FIG. 1.
As can be seen from FIG. 1, the PXRD characterization result shows that the SSZ-74 molecular sieve obtained by the application has a characteristic diffraction peak of the-SVR molecular sieve and is a pure-SVR molecular sieve; SEM shows that the SSZ-74 molecular sieve obtained by the application is nano flaky crystal, the crystal surface is smooth, and the size is about 500 x 300 x 50nm. And the micropore diameter of the crystal is distributed at 0.3-0.5 nanometer.
The solid nuclear magnetic NMR characterization of H and Al was performed on the resulting SSZ-74 molecular sieve, and the results are shown in FIGS. 6 and 7.
As can be seen from FIG. 6, the SSZ-74 molecular sieve obtained in the present application has characteristic ordered silicon hydroxyl peaks specific to the SVR molecular sieve in the vicinity of 10ppm, and as can be seen from FIG. 7, the coordination states of aluminum in the SSZ-74 molecular sieve material obtained in the present application are all framework aluminum.
In summary, the characterization results prove that the high crystallinity-SVR molecular sieve can be prepared by the method of the application.
Example 2
In this example 2, a SSZ-74 molecular sieve having a silica to alumina ratio of 30 was prepared by adding seed crystals, comprising the following:
1) Silica sol (40 wt% SiO 2), sodium metaaluminate, sodium hydroxide solid powder and hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) are respectively used as a silicon source, an aluminum source, alkali and a template agent to be mixed, and the mixture is stirred at room temperature for overnight to obtain a gel mixture. Wherein, the mole number of SiO 2 is obtained by converting the mass of a silicon source according to the mole number of silicon element; converting the mass of an aluminum source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of silicon source, aluminum source, base, templating agent, and water (SiO 2：Al2O3：NaOH：R：H2 o=1.0:0.0167:0.15:0.4:40) was 1.0:0.0167:0.15:0.4:40.
2) Adding SSZ-74 molecular sieve seed crystal, transferring to a reaction kettle for crystallization, cooling, filtering, washing, drying at 80 ℃ and roasting at 550 ℃ to obtain the SSZ-74 molecular sieve. Wherein, SSZ-74 molecular sieve seed crystal is a completely crystallized dry-SVR structure molecular sieve containing a template agent, the adding amount of the seed crystal is 10% of the solid content of the gel mixture based on the solid content of the gel mixture, and the crystallization conditions are as follows: crystallizing at 160 deg.c for 168 hr at 30rpm.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 30.
The resulting SSZ-74 molecular sieves, PXRD and SEM, were characterized and the results are shown in FIG. 2.
As can be seen from FIG. 2, the PXRD characterization result shows that the SSZ-74 molecular sieve obtained by the application has a characteristic diffraction peak of the-SVR molecular sieve and is a pure-SVR molecular sieve; SEM shows that the SSZ-74 molecular sieve is nano granular crystal, which has certain aggregation and accumulation and average grain size of about 50nm. And the micropore diameter of the crystal is distributed at 0.3-0.5 nanometer.
In summary, the characterization results prove that the high crystallinity-SVR molecular sieve can be prepared by the method of the application.
Example 3
In this example 3, SSZ-74 molecular sieves having a silica to alumina ratio of 180 were prepared without adding seed crystals, and included as follows:
1) Silica sol (40 wt% SiO 2), sodium metaaluminate, sodium hydroxide solid powder and hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) are respectively used as a silicon source, an aluminum source, alkali and a template agent to be mixed, and the mixture is stirred at room temperature for overnight to obtain a gel mixture. Wherein, the mole number of SiO 2 is obtained by converting the mass of a silicon source according to the mole number of silicon element; converting the mass of an aluminum source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of silicon source, aluminum source, base, templating agent, and water (SiO 2：Al2O3：NaOH：R：H2 o=1.8:0.005:0.1:0.4:40) was 1.8:0.005:0.1:0.4:40.
2) Adding SSZ-74 molecular sieve seed crystal, transferring to a reaction kettle for crystallization, cooling, filtering, washing, drying at 80 ℃ and roasting at 550 ℃ to obtain the SSZ-74 molecular sieve. Wherein, SSZ-74 molecular sieve seed crystal is the high temperature roasting product of the dry-SVR structure molecular sieve containing template agent, the solid content of the gel mixture is taken as the reference, the adding amount of the seed crystal is 10% of the solid content of the gel mixture, and the crystallization conditions are: crystallizing at 160 deg.c for 96 hr at 30rpm.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 180.
The resulting SSZ-74 molecular sieves, PXRD and SEM, were characterized and the results are shown in FIG. 3.
As can be seen from FIG. 3, the PXRD characterization result shows that the SSZ-74 molecular sieve obtained by the application has a characteristic diffraction peak of the-SVR molecular sieve and is a pure-SVR molecular sieve; SEM shows that the SSZ-74 molecular sieve obtained by the application is nano flaky crystal, the crystal size is about 5 x2 x 0.2um, and the crystal surface is smooth. And the micropore diameter of the crystal is distributed at 0.3-0.5 nanometer.
In summary, the characterization results prove that the high crystallinity-SVR molecular sieve can be prepared by the method of the application.
Example 4
In this example 4, SSZ-74 molecular sieves having a silica to alumina ratio of 50 were prepared without adding seed crystals, and included as follows:
1) Silica sol (40 wt% SiO 2), sodium metaaluminate, sodium hydroxide solid powder and hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) are respectively used as a silicon source, an aluminum source, alkali and a template agent to be mixed, and the mixture is stirred at room temperature for overnight to obtain a gel mixture. Wherein, the mole number of SiO 2 is obtained by converting the mass of a silicon source according to the mole number of silicon element; converting the mass of an aluminum source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of silicon source, aluminum source, base, templating agent, and water (SiO 2：Al2O3：NaOH：R：H2 o=1.0:0.01:0.1:0.4:40) was 1.0:0.01:0.1:0.4:40.
2) Transferring the gel mixture obtained in the step 1) into a reaction kettle for crystallization, and after crystallization, cooling, filtering, washing, drying at 80 ℃ and roasting at 550 ℃ the crystallized product to obtain the SSZ-74 molecular sieve. Wherein, crystallization conditions are as follows: crystallizing at 160 deg.c for 96 hr at 30rpm.
In this example, the SSZ-74 molecular sieve product has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 5
In this example 5, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared without adding seed crystals, comprising the following:
This embodiment 5 is different from embodiment 4 in that: the crystallization temperature and time were different, and the crystallization was performed at 140℃for 168 hours, the rest was the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 6
In this example 6, SSZ-74 molecular sieves having a silica to alumina ratio of 50 were prepared without adding seed crystals.
This embodiment 6 is different from embodiment 4 in that: the crystallization temperature and time were different, and the crystallization was performed at 180℃for 96 hours, the rest being the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 7
In this example 7, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared without adding seed crystals and high basicity, comprising the following:
1) Silica sol (40 wt% SiO 2), sodium metaaluminate, sodium hydroxide solid powder and hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) are respectively used as a silicon source, an aluminum source, alkali and a template agent to be mixed, and the mixture is stirred at room temperature for overnight to obtain a gel mixture. Wherein, the mole number of SiO 2 is obtained by converting the mass of a silicon source according to the mole number of silicon element; converting the mass of an aluminum source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of silicon source, aluminum source, base, templating agent, and water (SiO 2：Al2O3：NaOH：R：H2 o=1.0:0.01:0.2:0.4:40) was 1.0:0.01:0.2:0.4:40.
2) Transferring the gel mixture obtained in the step 1) into a reaction kettle for crystallization, and after crystallization, cooling, filtering, washing, drying at 80 ℃ and roasting at 550 ℃ the crystallized product to obtain the SSZ-74 molecular sieve. Wherein, crystallization conditions are as follows: crystallizing at 160 deg.c for 96 hr at 30rpm.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 8
In this example 8, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared without adding seed crystals and with low basicity, comprising the following:
1) Silica sol (40 wt% SiO 2), sodium metaaluminate, sodium hydroxide solid powder and hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) are respectively used as a silicon source, an aluminum source, alkali and a template agent to be mixed, and the mixture is stirred at room temperature for overnight to obtain a gel mixture. Wherein, the mole number of SiO 2 is obtained by converting the mass of a silicon source according to the mole number of silicon element; converting the mass of an aluminum source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of silicon source, aluminum source, base, templating agent, and water (SiO 2：Al2O3：NaOH：R：H2 o=1.0:0.01:0.05:0.4:40) was 1.0:0.01:0.05:0.4:40.
2) Transferring the gel mixture obtained in the step 1) into a reaction kettle for crystallization, and after crystallization, cooling, filtering, washing, drying at 80 ℃ and roasting at 550 ℃ the crystallized product to obtain the SSZ-74 molecular sieve. Wherein, crystallization conditions are as follows: crystallizing at 160 deg.c for 96 hr at 30rpm.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 9
In this example 9, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared without adding seed crystals and under high concentration conditions, and included the following:
1) Silica sol (40 wt% SiO 2), sodium metaaluminate, sodium hydroxide solid powder and hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) are respectively used as a silicon source, an aluminum source, alkali and a template agent to be mixed, and the mixture is stirred at room temperature for overnight to obtain a gel mixture. Wherein, the mole number of SiO 2 is obtained by converting the mass of a silicon source according to the mole number of silicon element; converting the mass of an aluminum source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of silicon source, aluminum source, base, templating agent, and water (SiO 2：Al2O3：NaOH：R：H2 o=1.0:0.01:0.1:0.4:10) was 1.0:0.01:0.1:0.4:10.
2) Transferring the gel mixture obtained in the step 1) into a reaction kettle for crystallization, and after crystallization, cooling, filtering, washing, drying at 80 ℃ and roasting at 550 ℃ the crystallized product to obtain the SSZ-74 molecular sieve. Wherein, crystallization conditions are as follows: crystallizing at 160 deg.c for 96 hr at 30rpm.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 10
In this example 10, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared without adding seed crystals and at a low concentration, comprising the following:
1) Silica sol (40 wt% SiO 2), sodium metaaluminate, sodium hydroxide solid powder and hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) are respectively used as a silicon source, an aluminum source, alkali and a template agent to be mixed, and the mixture is stirred at room temperature for overnight to obtain a gel mixture. Wherein, the mole number of SiO 2 is obtained by converting the mass of a silicon source according to the mole number of silicon element; converting the mass of an aluminum source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of silicon source, aluminum source, base, templating agent, and water (SiO 2：Al2O3：NaOH：R：H2 o=1.0:0.01:0.1:0.4:50) was 1.0:0.01:0.1:0.4:50.
2) Transferring the gel mixture obtained in the step 1) into a reaction kettle for crystallization, and after crystallization, cooling, filtering, washing, drying at 80 ℃ and roasting at 550 ℃ the crystallized product to obtain the SSZ-74 molecular sieve. Wherein, crystallization conditions are as follows: crystallizing at 160 deg.c for 168 hr at 30rpm.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 11
In this example 11, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared without the addition of seed crystals and low template concentration, comprising the following:
1) Silica sol (40 wt% SiO 2), sodium metaaluminate, sodium hydroxide solid powder and hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) are respectively used as a silicon source, an aluminum source, alkali and a template agent to be mixed, and the mixture is stirred at room temperature for overnight to obtain a gel mixture. Wherein, the mole number of SiO 2 is obtained by converting the mass of a silicon source according to the mole number of silicon element; converting the mass of an aluminum source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of silicon source, aluminum source, base, templating agent, and water (SiO 2：Al2O3：NaOH：R：H2 o=1.0:0.01:0.1:0.2:40) was 1.0:0.01:0.1:0.2:40.
2) Transferring the gel mixture obtained in the step 1) into a reaction kettle for crystallization, and after crystallization, cooling, filtering, washing, drying at 80 ℃ and roasting at 550 ℃ the crystallized product to obtain the SSZ-74 molecular sieve. Wherein, crystallization conditions are as follows: crystallizing at 160 deg.c for 168 hr at 30rpm.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 12
In this example 12, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared without the addition of seed crystals and high template concentrations, comprising the following:
1) Silica sol (40 wt% SiO 2), sodium metaaluminate, sodium hydroxide solid powder and hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) are respectively used as a silicon source, an aluminum source, alkali and a template agent to be mixed, and the mixture is stirred at room temperature for overnight to obtain a gel mixture. Wherein, the mole number of SiO 2 is obtained by converting the mass of a silicon source according to the mole number of silicon element; converting the mass of an aluminum source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of silicon source, aluminum source, base, templating agent, and water (SiO 2：Al2O3：NaOH：R：H2 o=1.0:0.01:0.1:0.5:40) was 1.0:0.01:0.1:0.5:40.
2) Transferring the gel mixture obtained in the step 1) into a reaction kettle for crystallization, and after crystallization, cooling, filtering, washing, drying at 80 ℃ and roasting at 550 ℃ the crystallized product to obtain the SSZ-74 molecular sieve. Wherein, crystallization conditions are as follows: crystallizing at 160 deg.c for 168 hr at 30rpm.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 13
In this example 13, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared without adding seed crystals and at high rotational speeds, comprising the following:
1) Silica sol (40 wt% SiO 2), sodium metaaluminate, sodium hydroxide solid powder and hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) are respectively used as a silicon source, an aluminum source, alkali and a template agent to be mixed, and the mixture is stirred at room temperature for overnight to obtain a gel mixture. Wherein, the mole number of SiO 2 is obtained by converting the mass of a silicon source according to the mole number of silicon element; converting the mass of an aluminum source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of silicon source, aluminum source, base, templating agent, and water (SiO 2：Al2O3：NaOH：R：H2 o=1.0:0.01:0.1:0.4:40) was 1.0:0.01:0.1:0.4:40.
2) Transferring the gel mixture obtained in the step 1) into a reaction kettle for crystallization, and after crystallization, cooling, filtering, washing, drying at 80 ℃ and roasting at 550 ℃ the crystallized product to obtain the SSZ-74 molecular sieve. Wherein, crystallization conditions are as follows: crystallizing at 160 deg.c for 168 hr at 60rpm.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 14
In this example 14, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared without adding seed crystals and in a static state, comprising the following:
1) Silica sol (40 wt% SiO 2), sodium metaaluminate, sodium hydroxide solid powder and hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) are respectively used as a silicon source, an aluminum source, alkali and a template agent to be mixed, and the mixture is stirred at room temperature for overnight to obtain a gel mixture. Wherein, the mole number of SiO 2 is obtained by converting the mass of a silicon source according to the mole number of silicon element; converting the mass of an aluminum source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of silicon source, aluminum source, base, templating agent, and water (SiO 2：Al2O3：NaOH：R：H2 o=1.0:0.01:0.1:0.4:40) was 1.0:0.01:0.1:0.4:40.
2) Transferring the gel mixture obtained in the step 1) into a reaction kettle for crystallization, and after crystallization, cooling, filtering, washing, drying at 80 ℃ and roasting at 550 ℃ the crystallized product to obtain the SSZ-74 molecular sieve. Wherein, crystallization conditions are as follows: crystallizing at 160 deg.c for 168 hr.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 15
In this example 15, a pure silicon SSZ-74 molecular sieve was prepared without seed crystal and without aluminum source, comprising the following:
1) Silica sol (40 wt% SiO 2), sodium hydroxide solid powder and hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) are used as a silicon source, alkali and a template agent respectively, and the mixture is stirred at room temperature for overnight to obtain a gel mixture. Wherein, the mole number of SiO 2 is obtained by converting the mass of a silicon source according to the mole number of silicon element; the molar ratio of silicon source, base, templating agent, and water (SiO 2：NaOH：R：H2 o=1.0:0.01:0.1:0.4:40) was 1.0:0.01:0.1:0.4:40.
2) Transferring the gel mixture obtained in the step 1) into a reaction kettle for crystallization, and after crystallization, cooling, filtering, washing, drying at 80 ℃ and roasting at 550 ℃ the crystallized product to obtain the SSZ-74 molecular sieve. Wherein, crystallization conditions are as follows: crystallizing at 160 deg.c for 168 hr.
In this example, the SSZ-74 molecular sieve is pure silicon.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 16
In this example 16, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared with hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) and hexamethylene-1, 6-bis (dimethylethylammonium bromide) without adding seed crystals, comprising the following:
1) Silica sol (40 wt% of SiO 2), sodium metaaluminate, sodium hydroxide solid powder, hexamethylene-1, 6-bis (dimethylethylammonium hydroxide) and hexamethylene-1, 6-bis (dimethylethylammonium bromide) are respectively used as a silicon source, an aluminum source, alkali, a template agent 1 and a template agent 2 to be mixed, and the mixture is stirred at room temperature for overnight to obtain a gel mixture. Wherein, the mole number of SiO 2 is obtained by converting the mass of a silicon source according to the mole number of silicon element; converting the mass of an aluminum source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of silicon source, aluminum source, base, templating agent 1, templating agent 2, and water (SiO 2：Al2O3：NaOH：R1：R2：H2 o=1.0:0.01:0.1:0.3:0.1:40) was 1.0:0.01:0.1:0.3:40.
2) Transferring the gel mixture obtained in the step 1) into a reaction kettle for crystallization, and after crystallization, cooling, filtering, washing, drying at 80 ℃ and roasting at 550 ℃ the crystallized product to obtain the SSZ-74 molecular sieve. Wherein, crystallization conditions are as follows: crystallizing at 160 deg.c for 168 hr.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 17
In this example 17, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared using white carbon black as a silicon source, sodium metaaluminate as an aluminum source, and no seed crystal added, comprising:
this embodiment 17 is different from embodiment 4 in that: the crystallized silicon source was white carbon black, and the rest was the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 18
In this example 18, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared using tetramethyl orthosilicate as the silicon source, sodium metaaluminate as the aluminum source, and no seed crystal added, comprising the following:
the present embodiment 18 is different from embodiment 4 in that: as a silicon source for crystallization, tetramethyl orthosilicate (TMOS) was used, and the rest was the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 19
In this example 19, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared using tetraethyl orthosilicate as the silicon source, sodium metaaluminate as the aluminum source, and no seed crystal added, comprising the following:
This embodiment 19 is different from embodiment 4 in that: tetraethyl orthosilicate (TEOS) was used as the crystallized silicon source, and the rest was the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 20
In this example 20, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared using silica gel as the silicon source, sodium metaaluminate as the aluminum source, and no seed crystal added, and included the following:
The present embodiment 20 differs from embodiment 4 in that: the crystallized silicon source used was a silica gel, and the rest was the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 21
In this example 21, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared using pseudo-boehmite as an aluminum source, silica sol as a silicon source, and no seed crystal added, comprising the following:
this embodiment 21 differs from embodiment 4 in that: the crystallization of aluminum source using pseudo-boehmite was performed in the same manner as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 22
In this example 22, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared using alumina as the aluminum source, silica sol as the silicon source, and no seed crystal added, and included the following:
The present embodiment 22 differs from embodiment 4 in that: alumina was used as the crystallized aluminum source, and the rest was the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 23
In this example 23, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared using aluminum hydroxide as an aluminum source, silica sol as a silicon source, and no seed crystal added, and comprises the following:
This embodiment 23 is different from embodiment 4 in that: aluminum hydroxide was used as the aluminum source for crystallization, and the rest was the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50. The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 24
In this example 24, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared using aluminum sulfate as the aluminum source, silica sol as the silicon source, and no seed crystal added, and comprises the following:
This embodiment 24 is different from embodiment 4 in that: aluminum sulfate was used as the crystallized aluminum source, and the rest was the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 25
In this example 25, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared using aluminum isopropoxide as the aluminum source, silica sol as the silicon source, and no seed crystal added, and comprises the following:
this embodiment 25 is different from embodiment 4 in that: aluminum isopropoxide was used as the aluminum source for crystallization, and the rest was the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 26
In this example 26, an SSZ-74 molecular sieve having a silicon to aluminum ratio of 50 was prepared using aluminum powder as an aluminum source, silica sol as a silicon source, and no seed crystal added, and comprises the following:
the present embodiment 26 is different from embodiment 4 in that: aluminum powder was used as the crystallization aluminum source, and the rest was the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 27
In this example 27, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared with lithium hydroxide as the base and without the addition of seed crystals, comprising the following:
This embodiment 27 is different from embodiment 4 in that: the alkali source used for crystallization was lithium hydroxide, and the rest was the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 28
In this example 28, SSZ-74 molecular sieves having a silica to alumina ratio of 50 were prepared with potassium hydroxide as the base and without seed crystals, and included the following:
this embodiment 28 is different from embodiment 4 in that: the alkali source used for crystallization was potassium hydroxide, and the rest was the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 29
In this example 29, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared using rubidium hydroxide as the base and without adding seed crystals, comprising the following:
this embodiment 29 is different from embodiment 4 in that: the alkali source used for crystallization was rubidium hydroxide, and the rest was the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Example 30
In this example 30, an SSZ-74 molecular sieve having a silica to alumina ratio of 50 was prepared with cesium hydroxide as a base and without adding seed crystals, comprising the following:
The present embodiment 30 differs from embodiment 4 in that: the alkali source used for crystallization was cesium hydroxide, and the rest was the same as in example 4.
In this example, the SSZ-74 molecular sieve has a silica to alumina ratio of about 50.
The PXRD characterization result shows that the product obtained by the preparation method is a pure SSZ-74 molecular sieve.
Comparative example 1
This comparative example 1 differs from example 4 in that the ratio of templating agent is relatively low, specifically according to SiO 2：Al2O3：NaOH：R：H2 o=1.0: 0.005:0.1:0.05:40 was mixed in the same manner as in example 4. The obtained molecular sieve was subjected to PXRD observation, and the results are shown in fig. 4.
As can be seen from FIG. 4, the product obtained in the present application is ZSM-12 zeolite. The results indicate that too low a proportion of template results in the formation of other molecular sieves.
Comparative example 2
This comparative example 2 differs from example 4 in that the proportion of templating agent is relatively high, specifically according to SiO 2：Al2O3：NaOH：R：H2 o=1.0: 0.005:0.1:0.6:40 was mixed in the same manner as in example 4. The obtained molecular sieve was subjected to PXRD observation, and the results are shown in fig. 5.
As can be seen from FIG. 5, the product obtained in the present application is a lamellar phase. The results show that too high a proportion of templating agent results in the formation of lamellar phases.
Comparative example 3
This comparative example 3 differs from example 4 in that the water-to-silicon ratio of the gel mixture is too high, in particular according to SiO 2：Al2O3：NaOH：R：H2 o=1.0: 0.005:0.1:0.05:110, and the other components were mixed in the same manner as in example 13 to obtain an amorphous powder having no crystal structure.
The results indicate that too high a ratio of water to silicon in the gel mixture results in non-crystallization or failure to form a dense phase.
Comparative example 4
This comparative example 4 differs from example 13 in that the silica-alumina ratio of the gel mixture is too low, in particular according to SiO 2：Al2O3：NaOH：R：H2 o=1.0: 0.005:0.1:0.4:40, and the remainder were the same as in example 4 to obtain a powder containing both Y-type molecular sieves and SVR molecular sieves.
The results indicate that too low a ratio of silica to alumina in the gel mixture results in failure to form molecular sieves.
Comparative example 5
This comparative example 5 is different from comparative example 4 in that the crystallization temperature is low, the specific crystallization temperature is 100 ℃, and the rest is the same as comparative example 4, to obtain amorphous powder.
The results show that too low a crystallization temperature results in failure to form molecular sieves.
Comparative example 6
This comparative example 6 is different from comparative example 4 in that the crystallization time is too short, specifically, crystallization is performed at 160℃for 24 hours, and the remainder is the same as comparative example 4, to obtain amorphous powder.
The results show that too low a crystallization temperature results in failure to form molecular sieves.
As can be seen from the comprehensive embodiment, the method selects the template molecules which are different from the prior work, the template molecules are relatively easier to prepare and obtain and have lower cost, and the possibility of industrialized use of the-SVR molecular sieve is greatly improved. Meanwhile, the SVR molecular sieve prepared by the method has a nano sheet-like or nano particle shape, has a larger adjustable range of silicon-aluminum ratio, and has wider application space compared with the prior high-silicon/pure-silicon SVR molecular sieve. Furthermore, the SVR zeolite obtained by the invention is expected to show unique performance advantages in the fields of petrochemical industry or adsorption separation in industry and the like due to the simultaneous existence of ordered silicon hydroxyl groups and acidic aluminum sites in a framework. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.
Claims (8)
1. The preparation method of the SSZ-74 molecular sieve is characterized by comprising the following steps:
1) Mixing a silicon source, an aluminum source, a template agent, alkali and water to obtain a gel mixture;
2) Crystallizing the gel mixture in a sealed reaction kettle to obtain the SSZ-74 molecular sieve;
The silicon source is one or more of white carbon black, silica sol, tetramethyl orthosilicate, tetraethyl orthosilicate and silica gel;
The aluminum source is selected from one or more of pseudo-boehmite, aluminum oxide, aluminum hydroxide, sodium metaaluminate, aluminum sulfate, aluminum isopropoxide and metallic aluminum;
the alkali is selected from one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide and cesium hydroxide;
the template agent is selected from one or two of hexamethylene-1, 6-bis (dimethyl ethyl ammonium bromide) and hexamethylene-1, 6-bis (dimethyl ethyl ammonium hydroxide);
Converting the mass of the silicon source into the mole number of SiO 2 according to the mole number of silicon element; converting the mass of the aluminum source into the mole number of Al 2O3 according to the mole number of Al elements; the molar ratio of the silicon source to the aluminum source to the alkali to the template agent to the water is 1: (0-0.05): (0.05-0.3): (0.2-0.6): (5-100).
2. The method according to claim 1, wherein the crystallization temperature is 120 to 240 ℃;
and/or the crystallization time is 24-336 h;
And/or stirring during crystallization.
3. The method of claim 1, wherein in 2) the sealed reaction vessel further comprises a seed crystal.
4. The method of claim 3, wherein the seed crystals are selected from SSZ-74 molecular sieves;
and/or, the seed crystal is added in an amount of 0.001-60% of the solid content of the gel mixture based on the solid content of the gel mixture.
5. An SSZ-74 molecular sieve obtainable by the process of any one of claims 1 to 4.
6. The SSZ-74 molecular sieve of claim 5, wherein the SSZ-74 molecular sieve has a silica to alumina ratio of not less than 15;
and/or the SSZ-74 molecular sieve has a size of 30 nanometers to 5 micrometers;
And/or, the structure of the SSZ-74 molecular sieve is an SVR structure.
7. Use of SSZ-74 molecular sieves as claimed in claim 5 or 6 as catalysts in chemical reactions.
8. The use according to claim 7 wherein the chemical reaction comprises methanol to olefins, synthesis gas conversion, fischer-tropsch synthesis.
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| CN105772067A (en) * | 2014-12-26 | 2016-07-20 | 中国科学院大连化学物理研究所 | Double-pore-channel crystallization aluminosilicate molecular sieve catalyst and preparing method thereof |
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| CN105772067A (en) * | 2014-12-26 | 2016-07-20 | 中国科学院大连化学物理研究所 | Double-pore-channel crystallization aluminosilicate molecular sieve catalyst and preparing method thereof |
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