SSZ-39 molecular sieve as well as preparation method and application thereof

Abstract

The invention discloses an SSZ-39 molecular sieve as well as a preparation method and application thereof, and belongs to the technical field of molecular sieve materials. The SSZ-39 molecular sieve is prepared through proton exchange of an SSZ-39 molecular sieve precursor; the SSZ-39 molecular sieve precursor is prepared from a silicon source, an aluminum source, a structure-directing agent, an auxiliary agent, an alkali source and deionized water through a hydrothermal reaction. The SSZ-39 molecular sieve is characterized in that an organic silicon gel or tetraethyl orthosilicate organic silicon source is adopted as a silicon source, a triisopropyl aluminum or tributyl aluminum organic aluminum source is adopted as an aluminum source, a morpholine derivative is adopted as a structure-directing agent, the SSZ-39 molecular sieve is of a sphere-like structure, and the grain size is 50-100 nm. The SSZ-39 molecular sieve has wide application in catalysts, catalytic carriers, adsorbents and gas separating agents.

Description

Technical Field

[0001] The present invention relates to a material and a preparation method thereof, and particularly relates to an SSZ-39 molecular sieve, a preparation method and an application thereof, belonging to the technical field of molecular sieve materials. Background Art

[0002] As a molecular sieve material with unique structure and properties, SSZ-39 has attracted extensive attention in the catalytic field in recent years. Its special double six-membered ring structure endows it with excellent stability and catalytic activity under high-temperature and high-humidity environments. The synthesis methods of SSZ-39 mainly include the hydrothermal method and the dynamic crystallization method. The hydrothermal method is the most commonly used synthesis method, and high-crystallinity SSZ-39 molecular sieves are formed through a crystallization reaction under high-temperature and high-pressure conditions. The dynamic crystallization method further optimizes the crystal growth process by performing dynamic or static crystallization at different temperature segments, thereby improving the dispersibility and crystallinity of the crystals. Chinese Patent CN202410829792.7 discloses a molecular sieve and a preparation method thereof, which uses a silicon source, an aluminum source, an alkali source, and an organic template agent substitute as raw materials to form a gel, and the gel is crystallized into an SSZ-39 molecular sieve. The particle size distribution of the prepared SSZ-39 molecular sieve is 0.1 - 10 μm. Chinese Patent CN202310865546.2 discloses a preparation method of an SSZ-39 molecular sieve, which uses a cyclohexane derivative as a structure-directing agent. Due to the asymmetry of the structure-directing agent in structure, the crystallization efficiency of the SSZ-39 molecular sieve is accelerated, and the crystallization time of the SSZ-39 molecular sieve is shortened. The crystal morphology of the prepared SSZ-39 molecular sieve is a cube with a length of 0.5 - 5 μm, a width of 0.5 - 5 μm, and a height of 0.01 - 3 μm.

[0003] Nanoscale molecular sieves also exhibit excellent performance in the catalytic field. Due to their larger external surface area and higher intracrystalline diffusion rate, nanoscale molecular sieves show excellent performance in improving the utilization rate of catalysts, enhancing the conversion ability of macromolecules, reducing deep reactions, improving selectivity, and reducing coking deactivation. The existing SSZ-39 molecular sieves are all in the micron scale. Preparing SSZ-39 molecular sieves is of great significance for improving the performance of SSZ-39 molecular sieves and broadening the application scenarios of SSZ-39 molecular sieves. Summary of the Invention

[0004] The present invention provides a preparation method of an SSZ-39 molecular sieve. The SSZ-39 molecular sieve is obtained by proton exchange of an SSZ-39 molecular sieve precursor; the SSZ-39 molecular sieve precursor is prepared by a hydrothermal reaction of a silicon source, an aluminum source, a structure-directing agent, an auxiliary agent, an alkali source, and deionized water. The SSZ-39 molecular sieve has a spherical-like structure, and the crystal size is 50 - 100 nm.

[0005] Meanwhile, the present invention provides an SSZ-39 molecular sieve.

[0006] Meanwhile, the present invention provides an application of the SSZ-39 molecular sieve in a catalyst, a catalytic support, an adsorbent, a gas separator, especially the application of the SSZ-39 molecular sieve as a catalyst support in a denitrification reaction.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A preparation method of an SSZ-39 molecular sieve, comprising the following steps:

[0009] Step 01, at room temperature, add morpholine, an alcohol source, and a catalyst into a sealed reaction kettle, react at 110-140°C and 1-1.5 MPa for 24-48 h, cool to room temperature, sequentially add deionized water and dichloroethane, stir for 0.5-1 h, stand overnight, remove the water layer, and then perform vacuum distillation at 70-90°C for 3-5 h to remove low-boiling components, thereby obtaining a structure-directing agent precursor;

[0010] Step 02, at room temperature, add the structure-directing agent precursor obtained in Step 01, an alkylating agent, a solvent, and an acid-binding agent into a reaction kettle, react at 120-140°C and 1-2 MPa for 5-12 h, and perform vacuum distillation at 65-80°C to remove the solvent, thereby obtaining a crude structure-directing agent;

[0011] Step 03, at room temperature, add the crude structure-directing agent obtained in Step 02, deionized water, and calcium hydroxide into a reaction kettle, stir at 30-80°C for 2-3 h, filter to remove solid precipitates, let the liquid stand for 1-2 h, and separate and remove the upper-layer impurities (after standing, it will be layered into an aqueous phase and an oil phase, and the upper-layer oil phase is separated and removed), thereby obtaining a structure-directing agent;

[0012] Step 04, at room temperature, add a silicon source, an aluminum source, a structure-directing agent, an auxiliary agent, an alkali source, seeds, and deionized water into a reaction kettle, stir at 25-80°C for 1-5 h, then react at 160-200°C for 6-9 h, filter, wash, dry at 80-180°C for 12-24 h, and then calcine at 450-650°C for 3-10 h, cool to room temperature, thereby obtaining an SSZ-39 molecular sieve precursor;

[0013] Step 05, at room temperature, add the SSZ-39 molecular sieve precursor obtained in Step 04, a proton exchanger, and deionized water into a reaction kettle, react at 30-90°C for 2-12 h, filter, wash, dry at 80-180°C for 12-24 h, and then calcine at 450-650°C for 3-10 h, cool to room temperature, thereby obtaining an SSZ-39 molecular sieve.

[0014] Further, in step 01, the mass ratio of deionized water:dichloroethane:alcohol source:catalyst:morpholine is (10 - 20):(10 - 20):(3 - 5):(0.2 - 0.5):1; the alcohol source is selected from one of n - hexanol, n - heptanol or n - octanol; the catalyst is selected from trimethylamine hydrochloride - AlCl 3 or 1 - carboxymethyl - 3 - methylimidazolium hydrogensulfate.

[0015] Trimethylamine hydrochloride is a definite substance, CAS number: 593 - 81 - 7, trimethylamine hydrochloride - AlCl 3 is an ionic liquid catalyst synthesized from trimethylamine hydrochloride and AlCl 3 The preparation process of the catalyst: under N

[0016] protection, anhydrous AlCl 3 is added to trimethylamine hydrochloride while stirring, and when the molar ratio of AlCl 2 to trimethylamine hydrochloride reaches 2:1, stop stirring, place it in a vacuum drying oven and dry at 80°C for 4 h to obtain trimethylamine hydrochloride - AlCl 3 catalyst. 3 3

[0017] 1 - carboxymethyl - 3 - methylimidazolium hydrogensulfate is a definite substance, CAS number: 879270 - 11 - 8.

[0018] Further, in step 02, the mass ratio of the solvent:alkylating agent:acid - binding agent:precursor of structure - directing agent is (5 - 10):(3 - 5):(1 - 2):1; the solvent is selected from methanol or ethanol; the alkylating agent is selected from dimethyl carbonate or dimethyl sulfate; the acid - binding agent is selected from ethylenediamine or potassium hydroxide.

[0019] Further, in step 03, the mass ratio of deionized water:calcium hydroxide:crude structure - directing agent is (10 - 20):(1 - 2):1.

[0020] Further, in step 04, the mass ratio of deionized water:silica source:structure - directing agent:auxiliary agent:base source:seed crystal:aluminum source is (0.5 - 200):(2 - 10):(1 - 6):(0.5 - 2):(2 - 20):(0.01 - 0.05):1.

[0021] The seed crystal is a commercially available SSZ - 39 molecular sieve, purchased from Nanjing Yiming New Materials Technology Co., Ltd.

[0022] ​​Further, in step 04, the silicon source is selected from organosilica gel or tetraethyl orthosilicate; the aluminum source is selected from triisopropylaluminum or tributylaluminum; the base source is selected from sodium hydroxide or ethylenediamine; and the auxiliary agent is selected from isopropyl alcohol or tert-butanol.

[0023] Further, in step 05, the mass ratio of deionized water: proton exchanger: SSZ-39 molecular sieve precursor is (5 - 30): (0.2 - 1): 1.

[0024] Further, in step 05, the proton exchanger is selected from ammonium sulfate or sulfuric acid.

[0025] An SSZ-39 molecular sieve is a molecular sieve with an AEI-type framework structure composed of silicon-oxygen tetrahedra and aluminum-oxygen tetrahedra as basic structural units; the SSZ-39 molecular sieve has a spherical-like structure, and the crystal grain size is 50 - 100 nm, preferably 50 - 65 nm.

[0026] An SSZ-39 molecular sieve is prepared by proton exchange of an SSZ-39 molecular sieve precursor; the SSZ-39 molecular sieve precursor is prepared by a hydrothermal reaction of a silicon source, an aluminum source, a structure-directing agent, an auxiliary agent, a base source, and deionized water. The silicon source uses an organosilicon source, the aluminum source uses an organoaluminum source, and the structure-directing agent uses a morpholine derivative.

[0027] The Cu-SSZ-39 catalyst prepared from the SSZ-39 molecular sieve of the present invention has a denitrification efficiency of 90 - 93% at 180°C; and a denitrification efficiency of 99% at 200°C.

[0028] The preparation method of the Cu-SSZ-39 catalyst is as follows: The SSZ-39 molecular sieve is added to a 4 - 5% aqueous solution of copper acetate according to a solid-liquid ratio of 1: (10 - 20) g / mL, reacted at 5 - 80°C for 6 - 8 h, cooled, filtered, washed with deionized water until the washing liquid is neutral, dried at 60 - 80°C for 12 - 24 hours, and calcined at 300 - 500°C for 4 - 6 h to obtain the Cu-SSZ-39 catalyst.

[0029] An application of an SSZ-39 molecular sieve in a catalyst, a catalytic carrier, an adsorbent, and a gas separator.

[0030] An application of an SSZ-39 molecular sieve obtained by a preparation method of an SSZ-39 molecular sieve in a catalyst, a catalytic carrier, an adsorbent, and a gas separator.

[0031] The present invention has the following beneficial effects:

[0032] 1. The present invention modifies morpholine with C6-C8 alcohols and prepares morpholine derivatives through alkylation as structure-directing agents for the further preparation of SSZ-39 zeolite. Since C6-C8 alkyl groups are introduced into the morpholine structure, the morpholine derivatives prepared in the present invention have greater hydrophobicity compared with traditional piperidine derivative structure-directing agents. In the aqueous phase system for the preparation of SSZ-39 zeolite, under the induction of the more hydrophobic morpholine derivative structure-directing agent, during the crystallization process of SSZ-39 zeolite, a spherical-like morphology structure different from the traditional cubic morphology is formed. At the same time, the strong chemical bond formed between C6-C8 alcohols and morpholine is conducive to maintaining the stable hydrophobicity of the morpholine derivative structure-directing agent in the aqueous phase system, avoiding the entry of the morpholine derivative structure-directing agent into the aqueous phase during the crystallization process of SSZ-39 zeolite, and thus forming a traditional cubic SSZ-39 zeolite.

[0033] 2. The present invention uses an organosilicon source and an organoaluminum source to replace the traditional inorganic silicon source and inorganic aluminum source. During the preparation process of SSZ-39 zeolite, due to the strong electronegativity of the O atom in the morpholine derivative, the hydrolysis of the organosilicon source and the organoaluminum source generates silanol and aluminate species, which are rapidly adsorbed around the morpholine derivative structure-directing agent, thereby improving the crystallization rate of SSZ-39 zeolite; at the same time, the hydrolysis of the organosilicon source and the organoaluminum source generates organic substances that cooperate with the morpholine derivative structure-directing agent, resulting in the formation of smaller-sized spherical-like particles during the crystallization process of SSZ-39 zeolite, making it have higher catalytic activity.

[0034] 3. During the preparation process of SSZ-39 zeolite in the present invention, a morpholine derivative is used as a structure-directing agent. By utilizing the hydrophilicity of the O atom in the morpholine derivative, it can effectively prevent the complete entry of the morpholine derivative into the organic phase after the hydrolysis of the organosilicon source and the organoaluminum source, and complete separation from the silicon-aluminum species, losing the function of the structure-directing agent; at the same time, compared with traditional structure-directing agents, the morpholine derivative has better hydrothermal stability and is not easily decomposed in the preparation system of SSZ-39 zeolite, thereby reducing the consumption of the structure-directing agent during the preparation process of SSZ-39 zeolite and further reducing the production cost of SSZ-39 zeolite.

[0035] 4. Compared with the traditional preparation method of SSZ-39 zeolite, the present invention does not use other zeolites as the aluminum source for the preparation of SSZ-39 zeolite, which can effectively reduce the manufacturing cost of SSZ-39 zeolite; at the same time, by introducing seed crystals and utilizing the induction effect of the seed crystals, rapid crystallization of SSZ-39 zeolite is achieved, thereby improving the crystallization rate of SSZ-39 zeolite and reducing the production cost of SSZ-39 zeolite. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is the XRD pattern of the SSZ-39 zeolite in Example 1 of the present invention;

[0037] Figure 2 This is the scanning electron microscope image of the SSZ-39 molecular sieve in Example 1 of the present invention. Detailed implementation manners

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0039] Example 1

[0040] A preparation method of an SSZ-39 molecular sieve includes the following steps:

[0041] At room temperature, 10 g of morpholine, 30 g of n-hexanol, and 2 g of trimethylamine hydrochloride - AlCl 3 are added to a sealed reaction kettle, and reacted at 110 °C and 1 MPa for 24 h. After cooling to room temperature, 100 g of deionized water and 100 g of dichloroethane are added in sequence. After stirring for 0.5 h, it is left standing overnight. After removing the water layer, the low-boiling components are removed by vacuum distillation at 70 °C for 3 h to obtain a structure-directing agent precursor;

[0042] At room temperature, 10 g of the structure-directing agent precursor, 30 g of dimethyl carbonate, 50 g of methanol, and 10 g of ethylenediamine are added to the reaction kettle, and reacted at 120 °C and 1 MPa for 5 h. After removing the solvent by vacuum distillation at 65 °C, a crude structure-directing agent is obtained;

[0043] At room temperature, 10 g of the crude structure-directing agent, 100 g of deionized water, and 10 g of calcium hydroxide are added to the reaction kettle, stirred at 30 °C for 2 h, filtered to remove the solid precipitate, the liquid is left standing for 1 h, and the upper-layer impurities are removed to obtain a structure-directing agent;

[0044] At room temperature, 20 g of organosilica gel, 10 g of triisopropylaluminum, 10 g of the structure-directing agent, 5 g of isopropanol, 0.1 g of seed crystals, 20 g of sodium hydroxide, and 5 g of deionized water are added to the reaction kettle. After stirring at 25 °C for 1 h, it is reacted at 160 °C for 6 h, filtered, washed, dried at 80 °C for 12 h, and then calcined at 450 °C for 3 h. After cooling to room temperature, an SSZ-39 molecular sieve precursor is obtained;

[0045] At room temperature, 10 g of the SSZ-39 molecular sieve precursor, 2 g of ammonium sulfate, and 50 g of deionized water are added to the reaction kettle, reacted at 30 °C for 2 h, filtered, washed, dried at 80 °C for 12 h, and then calcined at 450 °C for 3 h. After cooling to room temperature, the SSZ-39 molecular sieve is obtained.

[0046] The application of a kind of SSZ-39 molecular sieve obtained in this embodiment in catalysts, catalytic supports, adsorbents, and gas separation agents, especially the application of SSZ-39 molecular sieve as a catalyst support in denitration reactions.

[0047] As Figure 1 shown, it is the XRD pattern of the SSZ-39 molecular sieve in this embodiment. It can be seen from the figure that the prepared molecular sieve has typical characteristic diffraction peaks of the SSZ-39 molecular sieve, and there are no other miscellaneous crystals, and the prepared SSZ-39 molecular sieve has a high crystallinity, indicating that the present invention has successfully prepared a high-crystallinity and high-purity SSZ-39 molecular sieve.

[0048] As Figure 2 shown, the SSZ-39 molecular sieve obtained in this embodiment is a silicon-aluminum molecular sieve with an AEI-type framework structure, which is a spherical-like structure with a grain size of 50 nm.

[0049] The prepared SSZ-39 molecular sieve was added to a 5% aqueous solution of copper acetate according to a solid-liquid ratio of 1:15 g / mL, reacted at 50 °C for 7 h, cooled, filtered, washed with deionized water until the washing liquid was neutral, dried at 70 °C for 12 hours, and calcined at 400 °C for 5 h to obtain the Cu-SSZ-39 catalyst, and NH 3 -SCR catalytic reaction performance test was carried out. The test conditions were: 500 ppm of NH 3 , 500 ppm of NO, 5 vol% of O 2 and N 2 as the balance gas. The catalyst activity test was carried out under the condition of a gas volume space velocity of 10000 h -1 , and the denitration efficiency of the catalyst is shown in Table 1.

[0050] Example 2

[0051] A preparation method of an SSZ-39 molecular sieve, comprising the following steps:

[0052] At room temperature, 10 g of morpholine, 50 g of n-heptanol, and 5 g of 1-carboxymethyl-3-methylimidazolium hydrogensulfate were added to a closed reaction kettle, reacted at 140 °C and 1.5 MPa for 48 h, cooled to room temperature, 200 g of deionized water and 200 g of dichloroethane were added in sequence, stirred for 1 h, left to stand overnight, after removing the water layer, the low-boiling components were removed by vacuum distillation at 90 °C for 5 h to obtain a structure-directing agent precursor;

[0053] At room temperature, 10 g of the structure-directing agent precursor, 50 g of dimethyl sulfate, 100 g of ethanol, and 20 g of potassium hydroxide were added to the reaction kettle, reacted at 140 °C and 2 MPa for 12 h, and the solvent was removed by vacuum distillation at 80 °C to obtain a crude structure-directing agent;

[0054] At room temperature, 10 g of the crude structure-directing agent, 200 g of deionized water, and 20 g of calcium hydroxide were added to a reaction kettle, stirred at 80 °C for 3 h, filtered to remove the solid precipitate, the liquid was allowed to stand for 2 h, and the upper-layer impurities were removed to obtain the structure-directing agent;

[0055] At room temperature, 100 g of tetraethyl orthosilicate, 10 g of tributylaluminum, 60 g of the structure-directing agent, 20 g of tert-butanol, 0.5 g of seed crystals, 200 g of ethylenediamine, and 2000 g of deionized water were added to a reaction kettle. After stirring at 80 °C for 5 h, the reaction was carried out at 200 °C for 9 h, filtered, washed, dried at 180 °C for 24 h, calcined at 650 °C for 10 h, and cooled to room temperature to obtain the SSZ-39 zeolite precursor;

[0056] At room temperature, 10 g of the SSZ-39 zeolite precursor, 10 g of sulfuric acid, and 300 g of deionized water were added to a reaction kettle, reacted at 90 °C for 12 h, filtered, washed, dried at 180 °C for 24 h, calcined at 650 °C for 10 h, and cooled to room temperature to obtain the SSZ-39 zeolite.

[0057] The SSZ-39 zeolite obtained in this example is a silica-aluminum zeolite with an AEI-type framework structure, having a spherical-like structure and a crystal grain size of 100 nm.

[0058] The application of an SSZ-39 zeolite obtained in this example in a catalyst, a catalytic support, an adsorbent, and a gas separator, especially the application of the SSZ-39 zeolite as a catalyst support in a denitration reaction.

[0059] Example 3

[0060] A preparation method of an SSZ-39 zeolite, comprising the following steps:

[0061] At room temperature, 10 g of morpholine, 40 g of n-octanol, and 3 g of trimethylamine hydrochloride - AlCl 3 were added to a closed reaction kettle, reacted at 130 °C and 1.2 MPa for 36 h, cooled to room temperature, 150 g of deionized water and 150 g of dichloroethane were added in sequence, stirred for 0.8 h, allowed to stand overnight, the water layer was removed, and the low-boiling components were removed by vacuum distillation at 80 °C for 4 h to obtain the structure-directing agent precursor;

[0062] At room temperature, 10 g of the structure-directing agent precursor, 40 g of dimethyl sulfate, 80 g of methanol, and 15 g of potassium hydroxide were added to a reaction kettle, reacted at 130 °C and 1.5 MPa for 10 h, and the solvent was removed by vacuum distillation at 75 °C to obtain the crude structure-directing agent;

[0063] At room temperature, 10 g of crude structure-directing agent, 150 g of deionized water, and 15 g of calcium hydroxide were added to a reaction kettle, stirred at 50 °C for 2.5 h, filtered to remove solid precipitates, the liquid was allowed to stand for 1.5 h, and the upper-layer impurities were removed to obtain the structure-directing agent;

[0064] At room temperature, 50 g of organosilica gel, 10 g of tributylaluminum, 30 g of structure-directing agent, 10 g of tert-butanol, 0.3 g of seed crystal, 100 g of sodium hydroxide, and 500 g of deionized water were added to a reaction kettle. After stirring at 60 °C for 3 h, the reaction was carried out at 160 °C for 7 h, filtered, washed, dried at 100 °C for 18 h, and then calcined at 550 °C for 8 h. After cooling to room temperature, the SSZ-39 zeolite precursor was obtained;

[0065] At room temperature, 10 g of SSZ-39 zeolite precursor, 8 g of sulfuric acid, and 200 g of deionized water were added to a reaction kettle. The reaction was carried out at 80 °C for 8 h, filtered, washed, dried at 140 °C for 18 h, and then calcined at 450 °C for 6 h. After cooling to room temperature, the SSZ-39 zeolite was obtained.

[0066] The SSZ-39 zeolite obtained in this example is a silica-alumina zeolite with an AEI-type framework structure, having a spherical-like structure and a crystal grain size of 65 nm.

[0067] The application of a kind of SSZ-39 zeolite obtained in this example in catalysts, catalytic carriers, adsorbents, gas separators, especially the application of SSZ-39 zeolite as a catalyst carrier in denitrification reactions.

[0068] Comparative Example 1 (In this comparative example, the traditional structure-directing agent 3,5-dimethyl-N,N-dimethylhydroxypiperidine was used)

[0069] A preparation method of SSZ-39 zeolite includes the following steps:

[0070] At room temperature, 20 g of organosilica gel, 10 g of triisopropylaluminum, 10 g of 3,5-dimethyl-N,N-dimethylhydroxypiperidine, 5 g of isopropanol, 0.1 g of seed crystal, 20 g of sodium hydroxide, and 5 g of deionized water were added to a reaction kettle. After stirring at 25 °C for 1 h, the reaction was carried out at 160 °C for 6 h, filtered, washed, dried at 80 °C for 12 h, and then calcined at 450 °C for 3 h. After cooling to room temperature, the SSZ-39 zeolite precursor was obtained;

[0071] At room temperature, 10 g of SSZ-39 zeolite precursor, 2 g of ammonium sulfate, and 50 g of deionized water were added to a reaction kettle. The reaction was carried out at 30 °C for 2 h, filtered, washed, dried at 80 °C for 12 h, and then calcined at 450 °C for 3 h. After cooling to room temperature, the SSZ-39 zeolite was obtained.

[0072] The SSZ-39 molecular sieve obtained in this comparative example is a silica-alumina molecular sieve with an AEI-type framework structure, having a conventional cubic structure morphology and a crystal grain size of 1.5 μm.

[0073] Comparative Example 2 (In the preparation of the SSZ-39 molecular sieve in this comparative example, conventional inorganic silicon sources and inorganic aluminum sources were used)

[0074] A method for preparing an SSZ-39 molecular sieve includes the following steps:

[0075] At room temperature, 10 g of morpholine, 30 g of n-hexanol, and 2 g of trimethylamine hydrochloride - AlCl 3 were added to a sealed reaction kettle, reacted at 110 °C and 1 MPa for 24 h, cooled to room temperature, 100 g of deionized water and 100 g of dichloroethane were successively added, stirred for 0.5 h, left to stand overnight, after removing the water layer, the low-boiling components were removed by vacuum distillation at 70 °C for 3 h to obtain a structure-directing agent precursor;

[0076] At room temperature, 10 g of the structure-directing agent precursor, 30 g of dimethyl carbonate, 50 g of methanol, and 10 g of ethylenediamine were added to the reaction kettle, reacted at 120 °C and 1 MPa for 5 h, and after removing the solvent by vacuum distillation at 65 °C, a crude structure-directing agent was obtained;

[0077] At room temperature, 10 g of the crude structure-directing agent, 100 g of deionized water, and 10 g of calcium hydroxide were added to the reaction kettle, stirred at 30 °C for 2 h, the solid precipitate was filtered off, the liquid was left to stand for 1 h, and the upper-layer impurities were removed to obtain a structure-directing agent;

[0078] At room temperature, 20 g of silica sol, 10 g of sodium aluminate, 10 g of the structure-directing agent, 5 g of isopropanol, 0.1 g of seed crystals, 20 g of sodium hydroxide, and 5 g of deionized water were added to the reaction kettle, stirred at 25 °C for 1 h, reacted at 160 °C for 6 h, filtered, washed, dried at 80 °C for 12 h, and then calcined at 450 °C for 3 h, cooled to room temperature to obtain an SSZ-39 molecular sieve precursor;

[0079] At room temperature, 10 g of the SSZ-39 molecular sieve precursor, 2 g of ammonium sulfate, and 50 g of deionized water were added to the reaction kettle, reacted at 30 °C for 2 h, filtered, washed, dried at 80 °C for 12 h, and then calcined at 450 °C for 3 h, cooled to room temperature to obtain the SSZ-39 molecular sieve.

[0080] The SSZ-39 molecular sieve obtained in this comparative example is a silica-alumina molecular sieve with an AEI-type framework structure, having a spherical-like particle morphology and a crystal grain size of 1.5 μm.

[0081] Comparative Example 3 (In the preparation of the SSZ-39 molecular sieve in this comparative example, a modified piperidine derivative was used as the structure-directing agent)

[0082] At room temperature, 10 g of piperidine, 30 g of n-hexanol, and 2 g of trimethylamine hydrochloride - AlCl 3 were added to a sealed reaction kettle, and the reaction was carried out at 110 °C and 1 MPa for 24 h. After cooling to room temperature, 100 g of deionized water and 100 g of dichloroethane were added successively. After stirring for 0.5 h, it was left to stand overnight. After removing the water layer, low-boiling components were removed by vacuum distillation at 70 °C for 3 h to obtain a structure-directing agent precursor;

[0083] At room temperature, 10 g of the structure-directing agent precursor, 30 g of dimethyl carbonate, 50 g of methanol, and 10 g of ethylenediamine were added to the reaction kettle, and the reaction was carried out at 120 °C and 1 MPa for 5 h. After removing the solvent by vacuum distillation at 65 °C, a crude structure-directing agent was obtained;

[0084] At room temperature, 10 g of the crude structure-directing agent, 100 g of deionized water, and 10 g of calcium hydroxide were added to the reaction kettle, and it was stirred at 30 °C for 2 h. The solid precipitate was removed by filtration, and the liquid was left to stand for 1 h to remove the upper-layer impurities, obtaining a structure-directing agent;

[0085] At room temperature, 20 g of organosilica gel, 10 g of triisopropylaluminum, 10 g of the structure-directing agent, 5 g of isopropanol, 0.1 g of seed crystal, 20 g of sodium hydroxide, and 5 g of deionized water were added to the reaction kettle. After stirring at 25 °C for 1 h, the reaction was carried out at 160 °C for 6 h. After filtration and washing, it was dried at 80 °C for 12 h and then calcined at 450 °C for 3 h. After cooling to room temperature, upon detection, the product was not the precursor of SSZ-39 zeolite, indicating that the modified piperidine in this example could not form SSZ-39 zeolite in the system of the present invention.

[0086] Comparative Example 4 (in this comparative example, unmodified morpholine was used as the structure-directing agent)

[0087] A method for preparing SSZ-39 zeolite, comprising the following steps:

[0088] At room temperature, 20 g of organosilica gel, 10 g of triisopropylaluminum, 10 g of morpholine, 5 g of isopropanol, 0.1 g of seed crystal, 20 g of sodium hydroxide, and 5 g of deionized water were added to the reaction kettle. After stirring at 25 °C for 1 h, the reaction was carried out at 160 °C for 6 h. After filtration and washing, it was dried at 80 °C for 12 h and then calcined at 450 °C for 3 h. After cooling to room temperature, the precursor of SSZ-39 zeolite was obtained;

[0089] At room temperature, 10 g of the SSZ-39 molecular sieve precursor, 2 g of ammonium sulfate, and 50 g of deionized water were added to a reaction kettle, reacted at 30 °C for 2 h, filtered, washed, dried at 80 °C for 12 h, and then calcined at 450 °C for 3 h. After cooling to room temperature, upon detection, the product was not the SSZ-39 molecular sieve precursor. This shows that morpholine cannot be directly used as the structure-directing agent for the SSZ-39 molecular sieve.

[0090] The denitrification efficiencies of the catalysts obtained in Examples 1 to 3 and Comparative Examples 1 to 2 are shown in Table 1 below.

[0091] Table 1 Denitrification efficiencies of the catalysts in each example

[0092]

[0093] It should be understood that, in order to streamline the present disclosure and assist in understanding one or more of the various inventive aspects, in the above description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together into a single embodiment or the description thereof. However, the disclosed method should not be construed as reflecting the intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected by the claims, the inventive aspects lie in less than all the features of the previously disclosed embodiments. Thus, the claims following the detailed description are hereby expressly incorporated into the detailed description, where each claim stands on its own as a separate embodiment of the present invention.

[0094] Although the present invention has been described in terms of a limited number of embodiments, those skilled in the art in this technical field will appreciate, based on the above description, that other embodiments can be contemplated within the scope of the present invention thus described. In addition, it should be noted that the language used in this specification has been selected primarily for readability and teaching purposes, rather than for the purpose of explaining or limiting the subject matter of the present invention. Therefore, many modifications and variations will be apparent to those of ordinary skill in the art in this technical field without departing from the scope and spirit of the appended claims. The disclosure of the present invention is illustrative, not restrictive, of the scope of the present invention, which is defined by the appended claims.

[0095] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as within the protection scope of the present invention.

Claims

1. A method for preparing SSZ-39 molecular sieve, characterized in that: The following steps are involved: Step 01, at room temperature, add morpholine, alcohol source and catalyst into a closed reactor, react at 110-140°C and 1-1.5MPa for 24-48h, cool to room temperature, add deionized water and ethylene dichloride in sequence, the mass ratio of deionized water: ethylene dichloride: alcohol source: catalyst: morpholine is (10-20): (10-20): (3-5): (0.2-0.5): 1, stir for 0.5-1h, let stand overnight, remove the water layer, and distill at 70-90°C under reduced pressure for 3-5h to obtain a structure directing agent precursor; Step 02, at room temperature, adding the structure directing agent precursor, alkylating agent, solvent and acid binding agent prepared in step 01 into a reaction kettle, wherein the mass ratio of solvent: alkylating agent: acid binding agent: structure directing agent precursor is (5-10): (3-5): (1-2): 1, reacting at 120-140° C. and 1-2 MPa for 5-12 hours, and removing the solvent by reduced pressure distillation at 65-80° C. to obtain a crude structure directing agent; Step 03, at room temperature, add the crude structure directing agent obtained in step 02, deionized water, and calcium hydroxide into a reaction kettle, wherein the mass ratio of deionized water: calcium hydroxide: crude structure directing agent is (10-20): (1-2): 1, stir at 30-80° C. for 2-3 hours, filter to remove solid precipitate, let the liquid stand for 1-2 hours, separate the liquid to remove upper impurities, and obtain a structure directing agent; Step 04, at room temperature, add silicon source, aluminum source, structure directing agent, auxiliary agent, alkali source, seed crystal, and deionized water into a reactor, the mass ratio of deionized water: silicon source: structure directing agent: auxiliary agent: alkali source: seed crystal: aluminum source is (0.5-200): (2-10): (1-6): (0.5-2): (2-20): (0.01-0.05): 1, stir at 25-80°C for 1-5h, react at 160-200°C for 6-9h, filter, wash, dry at 80-180°C for 12-24h, calcine at 450-650°C for 3-10h, cool to room temperature, and obtain SSZ-39 molecular sieve precursor; Step 05, at room temperature, add the SSZ-39 molecular sieve precursor, proton exchanger and deionized water prepared in step 04 into a reactor, the mass ratio of deionized water: proton exchanger: SSZ-39 molecular sieve precursor is (5-30): (0.2-1): 1, react at 30-90°C for 2-12h, filter, wash, dry at 80-180°C for 12-24h, calcine at 450-650°C for 3-10h, cool to room temperature, and obtain SSZ-39 molecular sieve.

2. The preparation method according to claim 1, characterized in that: In step 01, the alcohol source is selected from one of n-hexanol, n-heptanol or n-octanol; the catalyst is selected from trimethylamine hydrochloride-AlCl3 or 1-carboxymethyl-3-methylimidazole hydrogen sulfate.

3. The preparation method according to claim 1, characterized in that: In step 02, the solvent is selected from methanol or ethanol; the alkylating agent is selected from dimethyl carbonate or dimethyl sulfate; and the acid binding agent is selected from ethylenediamine or potassium hydroxide.

4. The preparation method according to claim 1, characterized in that: In step 04, the silicon source is selected from silicone gel or tetraethyl orthosilicate; the aluminum source is selected from triisopropylaluminum or tributylaluminum; the alkali source is selected from sodium hydroxide or ethylenediamine; and the auxiliary agent is selected from isopropyl alcohol or tert-butyl alcohol.

5. The preparation method according to claim 1, characterized in that: In step 05, the proton exchanger is selected from ammonium sulfate or sulfuric acid.

6. The SSZ-39 molecular sieve obtained by the preparation method according to any one of claims 1 to 5, characterized in that: SSZ-39 molecular sieve has a quasi-spherical structure and a grain size of 50 to 100 nm.

7. The SSZ-39 molecular sieve according to claim 6, characterized in that The grain size is 50-65nm.

8. The Cu-SSZ-39 catalyst prepared from the SSZ-39 molecular sieve according to claim 6, characterized in that: The denitration efficiency of the Cu-SSZ-39 catalyst is 90-93% at 180°C and 99% at 200°C.

9. The Cu-SSZ-39 catalyst according to claim 8, characterized in that The preparation method is as follows: adding SSZ-39 molecular sieve to a 4-5% copper acetate aqueous solution at a solid-liquid ratio of 1: (10-20) g / mL, reacting at 5-80° C. for 6-8 hours, cooling, filtering, washing with deionized water until the washing liquid is neutral, drying at 60-80° C. for 12-24 hours, and calcining at 300-500° C. for 4-6 hours to obtain a Cu-SSZ-39 catalyst.

10. Use of the SSZ-39 molecular sieve according to claim 6 in catalysts, catalyst carriers, adsorbents, and gas separation agents.

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