An EU-1 molecular sieve with high specific surface area and its synthesis method

Abstract

This invention discloses an EU-1 molecular sieve and its synthesis method, belonging to the field of EU-1 molecular sieves; the EU-1 molecular sieve of this invention has a specific surface area S. BET ≥400m 2 / g, microporous specific surface area S micro ≥300m 2 / g; The synthesis method of the EU-1 molecular sieve includes the steps of mixing, aging, and segmental crystallization of a silicon source, an aluminum source, an alkali source, a template agent, and solvent I to obtain the EU-1 molecular sieve; the silicon source is a silicon source containing structural units; the synthesis method of the EU-1 molecular sieve of the present invention can modulate the induced nucleation microcrystals of the EU-1 molecular sieve within a wide range by controlling the crystallization time and temperature, thereby obtaining EU-1 molecular sieve products with high specific surface area and high crystallinity; by using a silicon source containing structural units as the silicon source, and by controlling the cations in the crystallization system, the EU-1 molecular sieve can be rapidly prepared, and the molecular sieve crystal morphology has the characteristics of uniform and highly dispersed.

Description

Technical Field

[0001] This invention relates to the field of EU-1 molecular sieve synthesis, specifically to an EU-1 molecular sieve with high specific surface area and its synthesis method. Background Technology

[0002] The development of high-performance molecular sieve materials is key to improving catalytic performance, resulting from the combined effects of pore structure and surface acidity; among these, pore structure and its parameters are crucial. EU-1 molecular sieves, belonging to the EUO topology, are a class of silicon-aluminum composite materials with a one-dimensional channel structure and regular porosity. They contain 10MR (ten-membered ring) through-hole micropores and perpendicularly connected 12MR (twelve-membered ring) side-bag structures. The side-bag openings are 0.68 nm × 0.58 nm in size and are interconnected with the outer surface of the crystal through 10MR micropores, with openings of 0.41 nm × 0.58 nm. The one-dimensional 10MR channels and their deep side cavities in EU-1 molecular sieves can create a unique shape-selective effect. Due to the special characteristics of its pore structure, EU-1 molecular sieves have been widely studied for applications in the petrochemical field. However, due to the one-dimensional pore structure, the morphology of synthesized EU-1 molecular sieves is usually spindle-shaped crystals, and the crystal size is usually at the micrometer level. Therefore, the ordered connectivity of the micropores is poor, which limits the mass transfer and diffusion of reacting molecules and the catalytic performance.

[0003] The performance of molecular sieves is closely related to their structure; pore type determines spatial confinement and electrostatic stabilization effects, thus playing different catalytic roles. (Studies in Surface Science &

[0004] Catalysis, 1991, 65(9):603-612). To date, the synthetic routes of EU-1 molecular sieves can be basically classified into two categories: hydrothermal methods based on liquid-phase transformation mechanisms and dry gel methods based on solid-phase transformation mechanisms. In these methods, a large amount of expensive and environmentally unfriendly organic template agents must be added to the synthesis system (the molar ratio of template agent to system silica is greater than 0.2). These template agents are usually highly toxic and expensive, and the production process also results in a high concentration of halogenated bromine, leading to poor production efficiency and economy of EU-1 molecular sieves. EU patent EP159845 discloses a method for synthesizing EUO structured molecular sieves using xylene dimethylamine (DBDMA) as a template agent. US Patent US2001 / 0051757A1 discloses a method for synthesizing EUO structured molecular sieves with a low silicon-to-aluminum ratio. The method uses diphenylmethyldimethylamine or its precursor as a structure directing agent and adds at least one seed crystal, including EUO type molecular sieves, to the synthesis system. The reaction mixture formed by uniformly mixing silicon source, aluminum source, alkali metal compound, template agent and seed crystals is subjected to hydrothermal crystallization to synthesize EU-1 molecular sieves with a Si / Al molar ratio of 5 to 50. Summary of the Invention

[0005] In order to overcome the problems of insufficient ordered connectivity of one-dimensional composite microporous channels, low channel regularity, and long crystallization cycle of conventional EU-1 molecular sieves, this invention provides an EU-1 molecular sieve with high specific surface area and its synthesis method.

[0006] To solve the above-mentioned technical problems, the first aspect of the present invention provides an EU-1 molecular sieve, wherein the specific surface area S of the EU-1 molecular sieve is... BET 400m 2 / g~700m 2 / g, microporous specific surface area S micro 300m 2 / g~500m 2 / g, the relative crystallinity of the EU-1 molecular sieve is 75% to 99%, and the average particle size of the crystals in the EU-1 molecular sieve is 5nm to 300nm.

[0007] According to some embodiments of the present invention, the silicon-aluminum molar ratio of the EU-1 molecular sieve is 5 to 500, preferably 25 to 270.

[0008] According to some embodiments of the present invention, the specific surface area S of the EU-1 molecular sieve BET 409m 2 / g~525m 2 / g, microporous specific surface area S micro 350m 2 / g~421m 2 / g, the relative crystallinity of the EU-1 molecular sieve is 85% to 99%, the average particle size of the crystals in the EU-1 molecular sieve is 10nm to 200nm, and its clear crystal structure can be observed by high-resolution electron microscopy.

[0009] According to some embodiments of the present invention, the EU-1 molecular sieve has a well-ordered and interconnected pore structure, and the diffraction spots are clear and regular as characterized by selected area electron diffraction (SAED). The EU-1 molecular sieve has the advantages of high dispersion and regular and uniform morphology.

[0010] A second aspect of the present invention provides a method for synthesizing the above-mentioned EU-1 molecular sieve, comprising the steps of mixing a silicon source, an aluminum source, an alkali source, a template agent and solvent I, aging, and crystallizing to obtain the EU-1 molecular sieve; wherein the silicon source is selected from silicon sources containing structural units;

[0011] In the ultraviolet Raman spectrum of the silicon source containing structural units, at a vibrational frequency of 240 cm⁻¹ -1There is a characteristic peak nearby, with a vibration frequency not exceeding 600 cm⁻¹. -1 In the characteristic region, there exists at least one non-240cm -1 The nearby characteristic peaks, and not at 240cm -1 The total peak area of ​​the nearby characteristic peaks is no more than 600 cm². -1 The total area of ​​the characteristic peaks in the characteristic region is ≥20% but not more than 98% (correspondingly, at 240 cm⁻¹). -1 The area of ​​the nearby characteristic peak is no more than 600 cm². -1 The total area of ​​the characteristic peaks in the characteristic region is ≤80%.

[0012] In some embodiments of the present invention, the ultraviolet Raman spectrum of the silicon source containing structural units has a vibration frequency not greater than 600 cm⁻¹. -1 In the characteristic region, there exists a vibration frequency of 335 cm. -1 400cm -1 and 480cm -1 At least one characteristic peak in the vicinity.

[0013] In this invention, the peak areas of the aforementioned characteristic peaks can be obtained automatically (or manually if necessary) through integration in a spectrometer. This invention does not limit the specific peak areas of the aforementioned characteristic peaks. However, for peaks other than 240 cm⁻¹... -1 The peak area of ​​the nearby characteristic peak and 240 cm -1 The relationship between the areas of nearby characteristic peaks is subject to certain constraints.

[0014] In this invention, the "silicon source containing structural units" refers to a silicon-containing four-membered ring (4MR), five-membered ring (5MR), or six-membered ring (6MR) that can form a molecular sieve framework structure.

[0015] According to the present invention, 240cm -1 The nearby characteristic peaks are characteristic signals of the TOT bending vibration of the silicon-containing octagonal ring (8MR), when the UV Raman spectrum of the silicon source containing the structural unit is at 240 cm⁻¹. -1 When a characteristic peak is present nearby, it indicates that the silicon atoms in the silicon source containing structural units have overcome the framework stress and formed more of the aforementioned 4MR, 5MR or 6MR active structural units.

[0016] According to the present invention, in the ultraviolet Raman spectrum of a silicon source containing structural units, at 240 cm⁻¹ -1 The characteristic peaks nearby indicate the bending vibrations of TOT in a silicon-containing octagon (8MR); at vibration frequencies not exceeding 600 cm⁻¹ -1 In the characteristic region, the smaller ring corresponds to a higher vibration frequency, not 240cm. -1 Among the nearby characteristic peaks, 335cm -1400cm -1 Or 480cm -1 The nearby characteristic peaks represent the bending vibrations of TOT in silicon-containing six-membered rings (6MR), five-membered rings (5MR), and four-membered rings (4MR), respectively. (If not 240 cm⁻¹) -1 The total peak area of ​​the nearby characteristic peaks is no more than 600 cm². -1 The total area of ​​characteristic peaks in the characteristic region is ≥20%, indicating that the silicon atoms in the silicon source containing structural units have a large number of active structural units such as four-membered rings (4MR), five-membered rings (5MR), or six-membered rings (6MR).

[0017] According to some embodiments of the present invention, in the ultraviolet Raman spectrum of the silicon source containing structural units, the vibrational frequency is not greater than 600 cm⁻¹. -1 In the characteristic region, not 240cm -1 The nearby characteristic peak is 335 cm. -1 400cm -1 and 4480cm -1 At least one of the nearby characteristic peaks.

[0018] According to some embodiments of the present invention, when the vibration frequency is not greater than 600 cm⁻¹ -1 In the characteristic region, not 240cm -1 The nearby characteristic peak (i.e., 335cm) -1 400cm -1 and 480cm -1 The total peak area of ​​at least one of the nearby characteristic peaks is no more than 600 cm⁻¹. -1 The total area of ​​characteristic peaks in the characteristic region is ≥50%.

[0019] Regarding the use of the term "nearby" in the above description, those skilled in the art will understand that, since characteristic peaks in ultraviolet Raman spectroscopy typically exhibit shifts, the positions of the characteristic peaks defined in this invention may deviate, such as 480 cm⁻¹. -1 Nearby feature peak at 450cm -1 ~500cm -1 The displacements between them. However, the vibrations represented by each characteristic peak can be determined by those skilled in the art.

[0020] In this invention, the above-mentioned "not greater than 600cm" -1 The "featured region" generally refers to 0cm. -1 ~600cm -1 (e.g., 150cm) -1 ~600cm -1The ultraviolet Raman spectral region of the silicon source containing structural units. Those skilled in the art will understand that if a characteristic peak appears in a region that is not usually characterized by characteristic peaks in a silicon source containing structural units, it should be verified whether it is an impurity peak formed by contamination.

[0021] According to some embodiments of the present invention, the specific surface area of ​​the silicon source containing structural units is 200 m². 2 / g~980m 2 / g, preferably 550m 2 / g~980m 2 / g.

[0022] According to some embodiments of the present invention, in the silicon source containing structural units, the mass fraction of SiO2 is >90%, preferably >95%, and more preferably >98%.

[0023] According to some embodiments of the present invention, the pore volume of the silicon source containing the structural unit is 0.2 cm³. 3 / g~3.0cm 3 / g.

[0024] The method for preparing the silicon source containing structural units includes the following steps:

[0025] S1. Provide a mixture I containing treatment reagent and solvent II;

[0026] S2. Mix the silicon-containing raw material with the mixture I to obtain mixture II;

[0027] S3. The mixture II is activated to obtain the activated product;

[0028] S4. The activated product is calcined to obtain the silicon source containing structural units.

[0029] According to some embodiments of the present invention, in step S1, the treatment reagent is selected from at least one of inorganic bases, fluorine-containing substances, organic bases, and ionic liquids containing organic anions; preferably at least one of ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, hydrofluoric acid, sodium fluoride, ammonium fluoride, silicon tetrafluoride, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6).

[0030] In this invention, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) is an imidazolium-type ionic liquid.

[0031] In this invention, the treatment reagent is preferably an organic quaternary ammonium base or a fluoride, specifically selected from at least one of hydrofluoric acid, sodium fluoride, ammonium fluoride, silicon tetrafluoride, tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrapropylammonium hydroxide.

[0032] In this invention, the treatment reagent is typically prepared into a solution of a certain concentration using water or alcohol as a solvent. For example, organic bases can be prepared as aqueous or alcoholic solutions, and those skilled in the art can choose according to the actual situation.

[0033] According to some embodiments of the present invention, in step S1, the solvent II is selected from at least one of water, alcohols and ionic liquids; preferably at least one of deionized water, methanol, ethanol, isopropanol, ethylene glycol and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6).

[0034] According to some embodiments of the present invention, in step S2, the silicon-containing raw material is selected from at least one of diatomaceous earth, water glass, (liquid phase) silica sol, silica fume, fumed silica sol, silica powder, silica resin microspheres, silica esters (such as tetramethyl silicate, tetraethyl silicate or tetrapropyl silicate), silicon tetrachloride and silane; wherein, the silane is preferably selected from at least one of tetramethylsilane Si(CH3)4, methyltrimethoxysilane MTMS, isobutylenetriethoxysilane, trichlorosilane SiHCl3 and tetraethoxysilane Si(OC2H5)4.

[0035] In this invention, the silicon-containing raw material is preferably liquid-phase silica sol, silicate ester, or silane.

[0036] In this invention, the aforementioned optional silicon-containing raw materials are all silicon-containing substances commonly used in the art.

[0037] According to some embodiments of the present invention, the molar ratio of the treatment reagent to SiO2 in the silicon-containing raw material (hereinafter referred to as the treatment reagent / SiO2 molar ratio) is 0.0001 to 10:1, preferably 0.0001 to 0.1:1.

[0038] According to some embodiments of the present invention, the molar ratio of solvent II to SiO2 in the silicon-containing raw material (hereinafter referred to as solvent II / SiO2 molar ratio) is 0.5 to 50:1.

[0039] According to some embodiments of the present invention, the molar ratio of the total hydroxide anions in the treatment reagent and the solvent II to the SiO2 in the silicon-containing raw material (hereinafter referred to as OH- / SiO2) is 2 to 60:1.

[0040] According to some embodiments of the present invention, in step S2, the conditions for mixing include: a stirring speed of 0 to 5000 rpm, preferably 0 to 50 rpm; and a temperature of 0 to 50°C, preferably 5 to 30°C.

[0041] According to some embodiments of the present invention, in step S3, the activation process (also known as the gelation process) is selected from... The process (preparing monodisperse SiO2 microspheres via alkaline hydrolysis of tetraethyl orthosilicate (TEOS)), hydrolysis, oligomer precipitation, alkali dissolution, and thermal melting are selected from at least one of these methods to emphasize the mineralization effect on silicon atoms.

[0042] Activation treatment in this invention The process includes mixing and hydrolysis steps; the hydrolysis step of the activation treatment is mainly controlled by controlling parameters such as hydrolysis catalyst (promoter or inhibitor) and temperature, stirring / ultrasound / irradiation, and time; the oligomer precipitation of the activation treatment includes steps such as hydrolysis, solvent network bonding and growth; the alkaline dissolution of the activation treatment includes adding a certain amount of ammonia water, sodium hydroxide or potassium hydroxide solution of a certain concentration to the above preparation process; the hot melting of the activation treatment refers to single-stage or segmented high-temperature heat treatment at 300-1000℃ for a certain period of time.

[0043] In this invention, the activation treatment preferably uses the optimized class. Process. Specifically, the hydrolysis, cementation, and SiO2 growth rates can be controlled by adjusting the solvent volume, temperature, and stirring speed to achieve uniformity and controllability of the silicon powder.

[0044] According to the present invention, Processing, hydrolysis, oligomer precipitation, alkali dissolution, and thermal melting are all conventional methods of this invention. This invention does not strictly limit the various parameters involved in the process, and those skilled in the art can determine them according to the actual situation.

[0045] According to some embodiments of the present invention, the conditions for activation treatment include: a temperature not exceeding 200°C (e.g., 0–200°C), preferably not exceeding 100°C (e.g., 0–100°C); and a treatment time of 1 hour to 500 days, preferably 12 hours to 12 days. More preferably, the activation treatment is completed by performing the treatment at temperatures of 0–10°C, 10–30°C, 30–80°C, and 80–100°C (segmented constant temperature heat treatment) for 0–120 hours (e.g., 1–120 hours).

[0046] According to some embodiments of the present invention, after obtaining the activated product in step S3, before performing the calcination treatment in step S4, the activated product can be subjected to a purification treatment. This involves removing water-soluble impurities and solvents, including all impurities specifically present such as physically adsorbed water, alcohols, salts, and ionic liquids, through methods such as forced-air drying and vacuuming. Simultaneously, the product can be allowed to simultaneously contain up to the amount of Si, C, H, O, F, S, Br, Cl, or MoO. x It consists of at least one of the following:

[0047] According to some embodiments of the present invention, in step S4, the conditions for the calcination treatment include: a temperature of 200–1000°C, preferably 400–600°C; and a time of 0.05–500 hours. More preferably, within a temperature range of 200–1000°C (preferably 400–600°C), at least two calcination temperatures are selected sequentially from low to high in an air atmosphere for calcination treatment of 0.05–2 hours each. For example, calcination treatment is carried out sequentially in an air atmosphere at 150–200°C, 250–350°C, 400–500°C, and 500–600°C for 0.05–2 hours.

[0048] According to some embodiments of the present invention, during the calcination process, a programmed temperature increase of 0.5 to 5 °C / min is used to raise the temperature from room temperature to the calcination temperature (i.e., 150 to 1000 °C, preferably 400 to 600 °C).

[0049] In this invention, the calcination treatment removes skeletal water of crystallization (desorption temperature at normal pressure is typically ≥200℃), sublimable fluorides, sulfur, or MoO. x Impurities, including at least one organic template agent, base or salt molecule that can be completely decomposed by high-temperature oxidation.

[0050] According to some embodiments of the present invention, the aluminum source is selected from at least one of aluminum sulfate, sodium aluminate, aluminum chloride, aluminum nitrate, and boehmite.

[0051] According to some embodiments of the present invention, the alkali source is selected from at least one of ammonia, sodium hydroxide, potassium hydroxide, rubidium hydroxide, and tetraethylammonium hydroxide;

[0052] According to some embodiments of the present invention, the template agent (OSDA) is selected from at least one of hexamethyldiammonium bromide, an aqueous solution or methanol solution of hexamethyldiammonium hydroxide, and a template agent precursor; preferably, the template agent precursor is prepared by dissolving a dihaloalkane and a monoamine in an organic solvent; preferably, the dihaloalkane is 1,6-dibromohexane or 1-chloro-6-bromohexane; preferably, the monoamine is trimethylamine; preferably, the organic solvent is acetone; the molar ratio of the dihaloalkane, the monoamine, and the organic solvent is (1-50):(3-100):(5-50); more preferably, the mass concentration of the hexamethyldiammonium hydroxide aqueous solution or methanol solution is 1%-40%, preferably 25%.

[0053] According to some embodiments of the present invention, the solvent I is selected from at least one of water, methanol, ethanol, isopropanol, imidazole ionic liquid, and [bmim]PF6 anionic ionic liquid.

[0054] According to some embodiments of the present invention, the initial gel mixture is obtained by mixing the silicon source, aluminum source, alkali source, template agent and solvent I; preferably, the molar ratio of the silicon source, aluminum source, alkali source, template agent and solvent I is (10-300):1:(0-300):(1-20):(20-2000), and more preferably (30-300):1:(0-100):(1-20):(20-2000).

[0055] According to some embodiments of the present invention, the aging is carried out at a temperature of 20°C to 25°C, and the aging time is 0h to 4h, preferably 0.5h to 4h.

[0056] In this invention, the molar ratio of cations (including inorganic alkali metal ions and organic quaternary ammonium ions) in the crystallization system, i.e., template agent and alkali source, is crucial. In the technical solution of this invention, the proportion of cations is appropriately controlled during the segmented crystallization stage of EU-1 molecular sieve to obtain microcrystalline EU-1 molecular sieve containing a large number of incompletely crystallized microcrystals. Then, hydrothermal crystallization is carried out using the traditional high-temperature method, which induces nucleation and improves the crystallization rate. The crystal size of the obtained EU-1 molecular sieve can even be significantly reduced to less than one-tenth of the size of the product synthesized by conventional methods.

[0057] According to some embodiments of the present invention, the crystallization adopts a segmented crystallization process, including pre-crystallization and crystallization; preferably, the pre-crystallization temperature is 30℃~120℃ and the pre-crystallization time is 0.5h~12h; more preferably, the crystallization temperature is 120℃~200℃ and the crystallization time is 12h~500h.

[0058] And / or, the crystallization process may further include steps of cooling, washing, and drying.

[0059] According to some embodiments of the present invention, the method for synthesizing the EU-1 molecular sieve includes the following steps:

[0060] 1) Mix the aluminum source with a portion of solvent I to obtain a solution A with a concentration of 0.5wt% to 60wt%, preferably 19.0wt% to 26.0wt%;

[0061] 2) Mix the silicon source with another portion of solvent I to obtain solvent B with a concentration of 1wt% to 95wt%, preferably 28.0wt% to 40.0wt%;

[0062] 3) While stirring, add solution B dropwise to solution A, and a gel will be formed in the reaction.

[0063] 4) Add template agent to the gel obtained in step 3), stir for 1 to 2 hours, adjust the pH to 10 to 14, and stir again to obtain the initial gel;

[0064] 5) The initial gel obtained in step 4) is transferred into a reaction vessel crystallization vessel and sealed. It is pre-crystallized at a temperature of 30℃~120℃ for 0.5h~12h, and then placed in a hydrothermal crystallization vessel at a temperature of 120℃~200℃ for 12h~500h. The crystallized product is cooled, filtered, washed and dried to obtain the final solid product, which is the EU-1 molecular sieve.

[0065] According to some embodiments of the present invention, in step 3), the dripping time is 5 min to 100 h.

[0066] This invention relates to an EU-1 molecular sieve with high specific surface area and its synthesis method. By using a silicon source containing structural units as the silicon source, a highly ordered EU-1 molecular sieve can be obtained in less than three days through segmented hydrothermal crystallization. It is generally believed that crystal growth involves nucleation, growth, and cessation of growth. Under the same crystallization conditions, the more nuclei the crystallization system can provide, the faster its crystallization rate, thus making it easier to generate nanocrystals with smaller particle sizes and relatively higher crystallinity. The segmented crystallization strategy has guiding activity because, through the low-temperature induction process, the crystallization system contains extremely small nuclei with a certain crystal structure, and their presence is the fundamental reason for accelerating rapid crystal growth. The relatively low-temperature induced crystallization stage already contains the nuclei of this molecular sieve. Because the nuclei particles are very small, they are very uniformly dispersed in the synthesis reaction mixture, thus having a good structure guiding effect. The technical solution of this invention effectively solves the problem of the ordered interconnection of micropores in one-dimensional EU-1 molecular sieves. The obtained EU-1 molecular sieve has high crystallinity and high specific surface area. SAED characterization shows clear diffraction spots and a high specific surface area S0. BET ≥400m 2 / g, while the microporous specific surface area S micro ≥300m 2 / g, exhibiting excellent mass transfer and diffusion properties for reactive molecules.

[0067] Beneficial effects:

[0068] The synthesis method of EU-1 molecular sieve with high specific surface area in this invention has two significant advantages. First, by controlling the crystallization time and temperature, the induced nucleation microcrystals of EU-1 molecular sieve can be modulated within a wide range, thereby obtaining EU-1 molecular sieve products with high specific surface area and high crystallinity (relative crystallinity greater than 85%). Second, by using a silicon source containing structural units as the silicon source, and by controlling the molar ratio of cations (including inorganic alkali metal ions and organic quaternary ammonium ions) in the crystallization system, i.e., the template agent to the alkali source, EU-1 molecular sieve can be rapidly prepared. The morphology of the molecular sieve crystals, as observed by high-resolution electron microscopy, shows that it has uniform and highly dispersed characteristics, and each individual crystal has a clear crystal face structure. Attached Figure Description

[0069] Figure 1 The XRD patterns of the EU-1 molecular sieves prepared in Examples 1, 2, and 3 of this invention are shown below.

[0070] Figure 2 HR-TEM image of the EU-1 molecular sieve prepared in Example 1 of this invention;

[0071] Figure 3 SAED diffraction spots of the EU-1 molecular sieve prepared in Example 1 of this invention;

[0072] Figure 4 The crystallization kinetics curves of the EU-1 molecular sieves prepared in Example 1 and Comparative Example 1 of this invention are shown.

[0073] Figure 5 This is a TEM image of a silicon source SG1 containing structural units obtained in Example 1 of the present invention;

[0074] Figure 6 The UV-Raman spectra of silicon source SG1 and silica A200 containing structural units obtained in Example 1 of this invention are shown below.

[0075] Figure 7 The nitrogen low-temperature adsorption-desorption (BET) curves of silicon source SG1 and silica A200 containing structural units obtained in Example 1 of the present invention are shown.

[0076] Figure 8 The image shows the FT-IR spectra of silicon source SG1 and silica A200 containing structural units obtained in Example 1 of this invention. Detailed Implementation

[0077] The present invention will be further described below with reference to the accompanying drawings and embodiments. However, the present invention is not limited to these embodiments.

[0078] The specific surface area S of the EU-1 molecular sieve in this invention BET Microporous specific surface area S micro The specific surface area (Si) of the samples was determined using a Tristar 3000 surface area analyzer manufactured by Micrometrics. Before testing, the samples underwent vacuum activation pretreatment at 300℃ for 6 hours. The testing temperature was -196℃, and the specific surface area Si of the samples was obtained from the analytical isotherm. BET Microporous specific surface area S micro Structured data.

[0079] In this invention, phase analysis (XRD testing) was performed using a Bruker D8 Focus diffractometer with a graphite monochromator, a Cu target Kα light source, a wavelength λ of 0.154 nm, a tube voltage of 40 kV, and a tube current of 40 mA. Diffraction signals were recorded within the 2θ range of 3–90° (scanning speed of 2° / min), and the relative crystallinity was estimated based on the characteristic peak areas (EU-1 molecular sieve at 2θ values ​​of 8.0°, 8.7°, 9.1°, 19.1°, 20.6°, 22.2°, 23.4°, and 24°). At positions 1°, 26.0°, 26.6° and 27.2°, there are characteristic diffraction peaks (020), (111), (021), (114), (240), (134), (025), (060), (400), (314) and (420) belonging to the EUO type topology. The sum of the areas of the above characteristic peaks and the ratio between the sum of the areas of the above characteristic peaks of the standard sample are used to obtain a percentage data, which is the relative crystallinity value.

[0080] The high-resolution scanning electron imaging (HR-TEM) images and SAED diffraction spot images in this invention were all taken using a Nova Nano SEM 450 microscope from FEI Corporation.

[0081] In this invention, XRD analysis was used to determine the relative crystallinity of EU-1 molecular sieves obtained at different crystallization times, and the crystallization kinetic curves of EU-1 molecular sieves under the corresponding synthesis conditions were obtained.

[0082] In this invention, the specific surface area and pore volume of the silicon source containing structural units were analyzed by low-temperature N2 adsorption-desorption analysis using a Tristar3000 specific surface area analyzer manufactured by Micrometrics. Before testing, the samples were pretreated by vacuum activation at 300℃ for 6 hours, and the test temperature was -196℃. The specific surface area, pore volume and other pore structure data of the test samples were obtained by analyzing the isotherms.

[0083] In this invention, the mass fraction of SiO2 in the silicon source containing structural units was determined by thermogravimetric TG-DTA analysis of the sample using a TGA Q500analyzer instrument (test conditions were air atmosphere, heating rate 10℃ / min).

[0084] In this invention, the FT-IR spectroscopy was performed using a Nexus 670 Fourier Transform Infrared Spectrometer (FT-IR) manufactured by Nicolet, USA, to analyze the skeletal vibration region of the sample. During testing, the sample powder was first diluted with KBr to approximately 3% by mass, then ground and mixed thoroughly in a mortar and pestle, pressed into a pellet, and placed in a vacuum chamber for testing. The testing resolution was 4 cm⁻¹. 1 32 scans were performed, and the test range was 400–4000 cm.-1 .

[0085] In the following examples, all chemical reagents used are commercially available products, and no special purification treatment was performed unless otherwise specified.

[0086] Example 1

[0087] This embodiment provides an EU-1 molecular sieve with a high specific surface area, and the synthesis method is as follows:

[0088] Sodium aluminate was dissolved in deionized water to obtain a 20.5 wt% solution A. Separately, methyltrimethoxysilane was dissolved in deionized water to obtain a 32.1 wt% solution B. The 32.1 wt% solution B was added dropwise to the 20.5 wt% solution A over 30 minutes with stirring at 50 rpm, and the mixture was stirred at 20°C to form a gel. Then, a 25 wt% hexamethyldiammonium hydroxide (HM(OH)2) methanol solution was added, and the mixture was stirred for 2 hours. The pH was adjusted to 12 with a 40 wt% sodium hydroxide aqueous solution, and the mixture was allowed to stand at 25°C for 2 hours to age, yielding an initial gel. This initial gel was then transferred to a sealed stainless steel reaction vessel and pre-crystallized at 120°C for 2 hours under hydrothermal conditions. After pre-crystallization, the vessel was removed and placed back into the vessel for crystallization at 175°C for 48 hours to obtain a crystallized product. The crystallized product was then cooled, filtered, washed, and dried to obtain the final solid product.

[0089] The final solid product obtained was EU-1 molecular sieve KE1. XRD analysis showed that it had an EUO structure. XRD results for KE1 are attached. Figure 1 The silicon-to-aluminum molar ratio in KE1 is 55, and the specific surface area S BET 438m 2 / g, microporous specific surface area S micro 372m 2 / g, the relative crystallinity of the crystal is 89%, and the average grain size is 30nm.

[0090] In the above, the molar ratio of methyltrimethoxysilane, sodium aluminate, sodium hydroxide, hexamethyldiammonium hydroxide HM(OH)2 methanol solution, and deionized water is 60:1:25:20:2800; methyltrimethoxysilane contains structural units; the preparation of the methyltrimethoxysilane containing structural units includes: weighing sodium hydroxide, sodium fluoride, and 25% ammonia solution, dissolving them evenly in deionized water, adding methanol, and placing the solution in a 5°C water bath; weighing methyltrimethoxysilane, adding it evenly to the above solution while stirring at 30 rpm, stirring for another 2 minutes, transferring it to a container, and letting it stand at 30°C for 5 hours to obtain a sol; and rotary evaporating the solvent under vacuum at 80°C until a solid mass precipitates out. The molar ratio of the treatment reagent / SiO2 is 0.05; the molar ratio of solvent II / SiO2 is 10; and the molar ratio of OH- / SiO2 is 10.

[0091] The solid mass obtained above was treated with a 1% citric acid aqueous solution at a liquid-to-solid mass ratio of approximately 6:1, and activated by acid exchange at 80°C for 1.5 hours. It was then washed with deionized water until electrically neutral and dried at 120°C. The temperature was then increased to 600°C at a rate of 3°C / min and calcined at this temperature for 1.5 hours to obtain methyltrimethoxysilane containing structural units, designated as sample SG1.

[0092] The specific surface area of ​​sample SG1 was determined to be S. BET 510m 2 / g, pore volume = 2.4cm³ 3 / g, SiO2 mass fraction is 99%, from Figure 6 It can be seen that, compared to silica A200, sample SG1 exhibits better performance at vibration frequencies not exceeding 600 cm⁻¹. -1 The characteristic region contains a higher proportion of non-240cm areas. -1 Nearby characteristic peaks; UV-Raman spectroscopy indicates its vibrational frequency is at 335 cm⁻¹. -1 400cm -1 and 4480cm -1 The area of ​​the nearby characteristic peak is greater than 240 cm⁻¹ -1 The characteristic peaks nearby, at non-240cm -1 The total peak area of ​​the nearby characteristic peaks is no more than 600 cm². -1 The total area of ​​the characteristic peaks in the characteristic region is 78%. Figure 6 In the UV-Raman spectrum of sample SG1, peak overlap occurred at 335 cm⁻¹. -1 400cm -1 and 480cm -1 The nearby characteristic peaks overlap.

[0093] Depend on Figure 5It can be seen that the silica particles in sample SG1 are uniform and dispersed; Figure 7 It can be seen that, compared to silica A200, sample SG1 exhibits a greater low-temperature adsorption capacity for nitrogen, and its specific surface area and pore volume are larger, as indicated by the curve. Figure 8 It can be seen that the signal peak of silanol in the corresponding FT-IR spectrum of sample SG1 is stronger (generally, the larger the peak area at the characteristic position, the higher the concentration of silanol on the surface of the sample).

[0094] Example 2

[0095] This embodiment provides an EU-1 molecular sieve with a high specific surface area, and the synthesis method is as follows:

[0096] Aluminum nitrate was dissolved in deionized water to obtain a 22.5 wt% solution A. Hexamethyldisilazane was dissolved in deionized water to obtain a 33.0 wt% solution B. The 33.0 wt% solution B was added dropwise to the 22.5 wt% solution A over 2 hours with stirring at 200 rpm, and the mixture reacted to form a gel at 25°C. Hexamethyldiamine bromide (HMBr2) and a 25 wt% hexamethyldiammonium hydroxide (HM(OH)2) ethanol solution were then added. After stirring for 1.5 hours, the pH was adjusted to 12.5 with a 30 wt% tetraethylammonium hydroxide aqueous solution, and the mixture was aged at 25°C for another 2 hours to obtain an initial gel. The initial gel was then transferred to a sealed stainless steel reaction vessel and pre-crystallized at 100°C for 6 hours under hydrothermal conditions. After pre-crystallization, the vessel was removed and placed back into the vessel for crystallization at 185°C for 24 hours to obtain a crystallized product. The crystallized product was then cooled, filtered, washed, and dried to obtain the final solid product.

[0097] In the above, the molar ratio of hexamethyldisilazane, aluminum nitrate, tetraethylammonium hydroxide, (hexamethyldiamine bromide HMBr2 and hexamethyldiammonium hydroxide HM(OH)2 ethanol solution) and deionized water is 120:1:30:15:1200, wherein the mass ratio of hexamethyldiamine bromide HMBr2 and hexamethyldiammonium hydroxide HM(OH)2 ethanol solution is 1:6; hexamethyldisilazane contains structural units; the preparation of the hexamethyldisilazane containing structural units is the same as in Example 1.

[0098] The final solid product obtained was EU-1 molecular sieve KE2. XRD analysis showed that it had an EUO structure. XRD results for KE2 are attached. Figure 1 The silicon-to-aluminum molar ratio in KE2 is 1:12, and the specific surface area S BET 417m 2 / g, microporous specific surface area S micro 355m 2 / g, the relative crystallinity of the crystal is 95%, and the average grain size is 18nm.

[0099] Comparative Example 1

[0100] This comparative example provides an EU-1 molecular sieve.

[0101] The initial gel was prepared according to the synthesis method of Example 1, except that, for the same molar amount, it was fumed silica sol A200 (specific surface area of ​​200 m²) produced by Degussa AG. 2 Using / g) as the silicon source, the final solid product was synthesized.

[0102] The final solid product obtained was EU-1 molecular sieve DE1, which XRD analysis showed to have an EUO structure; the silicon-aluminum molar ratio in DE1 was 37, and the specific surface area S BET 298m 2 / g, microporous specific surface area S micro 230m 2 / g, the relative crystallinity of the crystal is 87%, and the average grain size is 35nm.

[0103] Comparative Example 2

[0104] This comparative example provides an EU-1 molecular sieve.

[0105] The initial gel was prepared according to the synthesis method of Example 2, except that it was not pre-crystallized to induce nucleation, but was directly crystallized at a temperature of 180°C for 24 hours under hydrothermal conditions.

[0106] The final solid product obtained was EU-1 molecular sieve DE2, which XRD analysis showed to have an EUO structure; the silicon-to-aluminum molar ratio in DE2 was 49, and the specific surface area S BET 368m 2 / g, microporous specific surface area S micro 297m 2 / g, the relative crystallinity of the crystal is 79%, and the average grain size is 66nm.

[0107] Comparative Example 3

[0108] This comparative example provides an EU-1 molecular sieve.

[0109] The initial gel was prepared according to the synthesis method of Example 1, except that, on the same molar basis, hexamethyldiamine bromide (99%) was used instead of 25 wt% hexamethyldiamine hydroxide HM(OH)2 aqueous solution, and the pH value was adjusted to 11.9 using 22 wt% sodium hydroxide aqueous solution.

[0110] The final solid product obtained was EU-1 molecular sieve DE3. XRD analysis showed that it had an EUO structure and a conventional, approximately ellipsoidal morphology. The silicon-to-aluminum molar ratio in DE3 was 5:3, and the specific surface area S... BET 345m2 / g, microporous specific surface area S micro 286m 2 / g, the relative crystallinity of the crystals is 85%, and the average grain size is 55nm.

[0111] To further illustrate the advancements of the EU-1 molecular sieve KE1 prepared in Example 1 of this invention compared to the EU-1 molecular sieve DE1 prepared in Comparative Example 1, as follows: Figure 4 These are the crystallization kinetic curves of Example 1 and Comparative Example 1. The crystallization behavior of EU-1 molecular sieve KE1 prepared in Example 1 and EU-1 molecular sieve DE1 prepared in Comparative Example 1 were compared and analyzed, and the crystallization kinetic curves of EU-1 molecular sieve KE1 prepared in Example 1 and EU-1 molecular sieve DE1 prepared in Comparative Example 1 were recorded. In the crystallization kinetic experiment of this invention, the relative crystallinity of EU-1 molecular sieves obtained at different crystallization times was analyzed by XRD, and the crystallization kinetic curves of EU-1 molecular sieves under the corresponding synthesis conditions were obtained.

[0112] Depend on Figure 4 It is evident that different silicon sources have a significant impact on the induction period and growth crystallization behavior of EU-1 molecular sieves. In Comparative Example 1, the induction period using fumed silica sol A200 as the silicon source is relatively long, with crystallization only beginning around 48 hours. This aligns with the characteristics of EU-1 molecular sieves, where one-dimensional composite channels are difficult to nucleate and the crystallization cycle is relatively long. The crystallization growth curve slows down after 120 hours. Significantly different is the use of a silicon source containing structural units in Example 1 of this invention, which significantly shortens the induction period, achieving a crystallinity of over 80% after 48 hours of crystallization. This is mainly due to the longer Si-O bond length. Smaller than Al-O bond length OSDA cations and AlO4 - The interactions between the two groups differ. The weaker five-coordinate aluminum can be interconnected through the Al-O hydroxyl group, which can then undergo dehydroxylation and induce a topological transformation to four-coordinate. As the silicon-aluminum ratio increases, the unit cell shrinks, which shortens both the induction period and the crystallization period. A high silicon-aluminum ratio is more conducive to nucleation.

[0113] The crystallization kinetics of the EU-1 molecular sieve described above conforms to the synergistic crystallization mechanism and its crystal growth theory: the silicon source containing structural units is rich in structural units (such as four-membered rings, five-membered rings, or six-membered rings, which are TOT molecular sieve framework structural units). Under the structural guidance of hydrated cations, these structural units form polyhedra and have a certain network connectivity. The four-membered rings, five-membered rings, and six-membered rings are connected to form specific molecular sieve channels. The crystallinity gradually increases with the synergistic promotion of the two close processes, and crystallization forms a regular microporous structure and a uniform and highly dispersed molecular sieve crystal.

[0114] Furthermore, in Comparative Examples 1-3, EU-1 structural molecular sieves synthesized using fumed silica sol product A200 as the silicon source, without pre-crystallization-induced nucleation, and without regulating the crystallization system, exhibited significant deficiencies such as uneven morphology, low dispersion and agglomeration, poor specific surface area and microporous crystallinity, and disordered interconnectivity of the molecular sieve pore structure. In stark contrast, in Examples 1-2 of this invention, by adjusting the system alkalinity and performing segmented crystallization, the grain size of the molecular sieve product can be effectively controlled. This demonstrates that the silicon source containing structural units and segmented crystallization-induced nucleation are highly effective in reducing grain size. Simultaneously, the cation regulation of the crystallization system effectively improves the uniformity, high dispersion, and crystallinity of the product grain morphology, resulting in high crystallinity and regular microporous channels, achieving superior technical effects.

[0115] Example 3

[0116] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0117] The synthesis method is the same as in Example 1, except that the molar ratio of tetramethoxysilane, sodium aluminate, sodium hydroxide, hexamethyldiammonium hydroxide HM(OH)2 methanol solution and deionized water is 60:1:0:15:900.

[0118] The final solid product obtained was EU-1 molecular sieve KE3, and XRD analysis showed that it had an EUO structure. XRD results are attached. Figure 1 The silicon-to-aluminum molar ratio in KE3 is 54.5.

[0119] Example 4

[0120] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0121] The synthesis method is the same as in Example 1, except that the molar ratio of tetramethoxysilane, sodium aluminate, sodium hydroxide, hexamethyl diammonium hydroxide HM(OH)2 methanol solution and deionized water is 60:1:5:15:900.

[0122] The final solid product obtained was EU-1 molecular sieve KE4, which XRD analysis showed to have an EUO structure; the silicon-aluminum molar ratio in KE4 was 57.

[0123] Example 5

[0124] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0125] The synthesis method is the same as in Example 1, except that the molar ratio of tetramethoxysilane, sodium aluminate, sodium hydroxide, hexamethyl diammonium hydroxide HM(OH)2 methanol solution and deionized water is 60:1:10:15:900.

[0126] The final solid product obtained was EU-1 molecular sieve KE5, which XRD analysis showed to have an EUO structure; the silicon-aluminum molar ratio in KE5 was 56.8.

[0127] Example 6

[0128] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0129] The synthesis method is the same as in Example 1, except that the molar ratio of tetramethoxysilane, sodium aluminate, sodium hydroxide, hexamethyl diammonium hydroxide HM(OH)2 methanol solution and deionized water is 60:1:20:15:900.

[0130] The final solid product obtained was EU-1 molecular sieve KE6, which XRD analysis showed to have an EUO structure; the molar ratio of silicon to aluminum in KE6 was 54.7.

[0131] Example 7

[0132] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0133] The synthesis method is the same as in Example 1, except that the molar ratio of tetramethoxysilane, sodium aluminate, sodium hydroxide, hexamethyl diammonium hydroxide HM(OH)2 methanol solution and deionized water is 60:1:30:15:900.

[0134] The final solid product obtained was EU-1 molecular sieve KE7, which XRD analysis showed to have an EUO structure; the silicon-aluminum molar ratio in KE7 was 52.5.

[0135] Example 8

[0136] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0137] The synthesis method is the same as in Example 1, except that the molar ratio of tetramethoxysilane, sodium aluminate, sodium hydroxide, hexamethyl diammonium hydroxide HM(OH)2 methanol solution and deionized water is 60:1:60:15:900.

[0138] The final solid product obtained was EU-1 molecular sieve KE8, which XRD analysis showed to have an EUO structure; the silicon-aluminum molar ratio in KE8 was 51.3.

[0139] The specific surface area S of the EU-1 molecular sieves with high specific surface area prepared in Examples 3-8 above is... BET and the specific surface area of ​​micropores S micro The statistics are shown in Table 1 below;

[0140] Table 1

[0141]

[0142] Example 9

[0143] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0144] The synthesis method of Example 2 was followed, except that the molar ratio of hexamethyldisilazane, aluminum nitrate, tetraethylammonium hydroxide, (hexamethyldiamine bromide HMBr2 and hexamethyldiammonium hydroxide HM(OH)2 ethanol solution) and deionized water was 30:1:20:12:720; and the crystallization temperature was 140°C.

[0145] The final solid product obtained was EU-1 molecular sieve KE9, which XRD analysis showed to have an EUO structure; the silicon-aluminum molar ratio in KE9 was 28.

[0146] Example 10

[0147] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0148] The synthesis method of Example 2 was followed, except that the molar ratio of hexamethyldisilazane, aluminum nitrate, tetraethylammonium hydroxide, (hexamethyldiamine bromide HMBr2 and hexamethyldiammonium hydroxide HM(OH)2 ethanol solution) and deionized water was 50:1:20:16:720; and the crystallization temperature was 160°C.

[0149] The final solid product obtained was EU-1 molecular sieve KE10, which XRD analysis showed to have an EUO structure; the silicon-aluminum molar ratio in KE10 was 46.

[0150] Example 11

[0151] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0152] The synthesis method of Example 2 was followed, except that the molar ratio of hexamethyldisilazane, aluminum nitrate, tetraethylammonium hydroxide, (hexamethyldiamine bromide HMBr2 and hexamethyldiammonium hydroxide HM(OH)2 ethanol solution) and deionized water was 75:1:20:18:720; and the crystallization temperature was 180°C.

[0153] The final solid product obtained was EU-1 molecular sieve KE11, which XRD analysis showed to have an EUO structure; the silicon-aluminum molar ratio in KE11 was 59.

[0154] Example 12

[0155] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0156] The synthesis method of Example 2 was followed, except that the molar ratio of hexamethyldisilazane, aluminum nitrate, tetraethylammonium hydroxide, (hexamethyldiamine bromide HMBr2 and hexamethyldiammonium hydroxide HM(OH)2 ethanol solution) and deionized water was 90:1:20:20:720; and the crystallization temperature was 160°C.

[0157] The final solid product obtained was EU-1 molecular sieve KE12, which was shown by XRD to have an EUO structure; the molar ratio of silicon to aluminum in KE12 was 73.

[0158] Example 13

[0159] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0160] The synthesis method of Example 2 was followed, except that the molar ratio of hexamethyldisilazane, aluminum nitrate, tetraethylammonium hydroxide, (hexamethyldiamine bromide HMBr2 and hexamethyldiammonium hydroxide HM(OH)2 ethanol solution) and deionized water was 100:1:20:18:720; and the crystallization temperature was 180°C.

[0161] The final solid product obtained was EU-1 molecular sieve KE13, which was shown by XRD to have an EUO structure; the molar ratio of silicon to aluminum in KE13 was 87.5.

[0162] Example 14

[0163] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0164] The synthesis method of Example 2 was followed, except that the molar ratio of hexamethyldisilazane, aluminum nitrate, tetraethylammonium hydroxide, (hexamethyldiamine bromide HMBr2 and hexamethyldiammonium hydroxide HM(OH)2 ethanol solution) and deionized water was 120:1:20:20:720; and the crystallization temperature was 180°C.

[0165] The final solid product obtained was EU-1 molecular sieve KE14, which XRD analysis showed to have an EUO structure; the molar ratio of silicon to aluminum in KE14 was 10:9.

[0166] Example 15

[0167] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0168] The synthesis method of Example 2 was followed, except that the molar ratio of hexamethyldisilazane, aluminum nitrate, tetraethylammonium hydroxide, (hexamethyldiamine bromide HMBr2 and hexamethyldiammonium hydroxide HM(OH)2 ethanol solution) and deionized water was 150:1:20:20:720; and the crystallization temperature was 175°C.

[0169] The final solid product obtained was EU-1 molecular sieve KE15, which XRD analysis showed to have an EUO structure; the silicon-aluminum molar ratio in KE15 was 129.

[0170] Example 16

[0171] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0172] The synthesis method of Example 2 was followed, except that the molar ratio of hexamethyldisilazane, aluminum nitrate, tetraethylammonium hydroxide, (hexamethyldiamine bromide HMBr2 and hexamethyldiammonium hydroxide HM(OH)2 ethanol solution) and deionized water was 180:1:20:20:720; and the crystallization temperature was 190°C.

[0173] The final solid product obtained was EU-1 molecular sieve KE16, which XRD analysis showed to have an EUO structure; the silicon-aluminum molar ratio in KE16 was 157.

[0174] The specific surface area S of the EU-1 molecular sieves with high specific surface area prepared in Examples 9-16 above is... BET and the specific surface area of ​​micropores S micro The statistics are shown in Table 2 below;

[0175] Table 2

[0176]

[0177] Example 17

[0178] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0179] The synthesis method of Example 1 was followed, except that the 25wt% hexamethyl diammonium hydroxide HM(OH)2 solution was replaced with a template precursor, wherein the molar ratio of 1,6-dibromohexane:trimethylamine:acetone in the template precursor was 10:50:20.

[0180] The final solid product obtained was EU-1 molecular sieve KE17, which was shown by XRD to have an EUO structure; the molar ratio of silicon to aluminum in KE17 was 54.

[0181] Example 18

[0182] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0183] The synthesis method of Example 1 was followed, except that the 25wt% hexamethyl diammonium hydroxide HM(OH)2 solution was replaced with a template precursor, wherein the molar ratio of 1,6-dibromohexane:trimethylamine:acetone in the template precursor was 3:5:10.

[0184] The final solid product obtained was EU-1 molecular sieve KE18, which XRD analysis showed to have an EUO structure; the molar ratio of silicon to aluminum in KE18 was 56.

[0185] Example 19

[0186] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0187] The synthesis method of Example 1 was followed, except that the 25wt% hexamethyl diammonium hydroxide HM(OH)2 solution was replaced with a template precursor, wherein the molar ratio of 1,6-dibromohexane:trimethylamine:acetone in the template precursor was 25:50:25.

[0188] The final solid product obtained was EU-1 molecular sieve KE19, which XRD analysis showed to have an EUO structure; the silicon-aluminum molar ratio in KE19 was 56.5.

[0189] Example 20

[0190] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0191] The synthesis method of Example 1 was followed, except that the 25wt% hexamethyl diammonium hydroxide HM(OH)2 solution was replaced with a template precursor, wherein the molar ratio of 1,6-dibromohexane:trimethylamine:acetone in the template precursor was 15:60:30.

[0192] The final solid product obtained was EU-1 molecular sieve KE20, which was shown by XRD to have an EUO structure; the molar ratio of silicon to aluminum in KE20 was 55.

[0193] Example 21

[0194] This embodiment provides an EU-1 molecular sieve with a high specific surface area.

[0195] The synthesis method of Example 1 was followed, except that the 25wt% hexamethyldiammonium hydroxide HM(OH)2 solution was replaced with a template precursor, wherein the molar ratio of 1-chloro-6-bromohexane:trimethylamine:acetone in the template precursor was 10:50:20.

[0196] The final solid product obtained was EU-1 molecular sieve KE21, which XRD analysis showed to have an EUO structure; the silicon-aluminum molar ratio in KE21 was 51.8.

[0197] The specific surface area S of the EU-1 molecular sieves with high specific surface area prepared in Examples 17-21 above is... BET and the specific surface area of ​​micropores S micro The statistics are shown in Table 3 below;

[0198] Table 3

[0199]

[0200] Example 22

[0201] This embodiment provides an EU-1 molecular sieve with a high specific surface area, and the synthesis method is as follows:

[0202] Sodium aluminate (chemically pure, alumina content ≥41%, sodium oxide content ≥31%, the same below) was dissolved in deionized water to obtain a 23.0 wt% solution A. Separately, isobutylenetriethoxysilane was dissolved in deionized water to obtain a 31.9 wt% solution B. The 31.9 wt% solution B was added dropwise to the 23.0 wt% solution A over 40 min with stirring at 20 rpm, and the mixture was reacted to form a gel at 22°C. Then, a 25 wt% hexamethyldiammonium hydroxide (HM(OH)2) aqueous solution was added, and the mixture was stirred for 1 h. The pH was adjusted to 12.2 with a 13 wt% potassium hydroxide aqueous solution, and the mixture was aged at 22°C for 3 h to obtain an initial gel. The initial gel was then transferred to a sealed stainless steel reaction vessel and pre-crystallized at 120°C for 4 h under hydrothermal conditions, followed by crystallization at 180°C for 48 h to obtain a crystallized product. The crystallized product was then cooled, filtered, washed, and dried to obtain the final solid product.

[0203] In the above, the molar ratio of isobutylene triethoxysilane, sodium aluminate, potassium hydroxide, hexamethyl diammonium hydroxide HM(OH)2 aqueous solution and deionized water is 45:1:16:6:800; the above isobutylene triethoxysilane contains structural units; the preparation of the isobutylene triethoxysilane containing structural units is the same as in Example 1.

[0204] The final solid product obtained was EU-1 molecular sieve KE22, which XRD analysis showed to have an EUO structure; the silicon-to-aluminum molar ratio in KE22 was 52.8, and the specific surface area S... BET 427m 2 / g, microporous specific surface area S micro 355m 2 / g, the relative crystallinity of the crystals is 99%, and the average grain size is 11nm.

[0205] Example 23

[0206] This embodiment provides an EU-1 molecular sieve with a high specific surface area, and the synthesis method is as follows:

[0207] Sodium aluminate (chemically pure, with an aluminum oxide content ≥41% and a sodium oxide content ≥31%, the same below) was dissolved in deionized water to obtain a 24.5 wt% solution A. Separately, isobutylenetriethoxysilane was dissolved in deionized water to obtain a 32.5 wt% solution B. This 32.5 wt% solution B was added dropwise to a 24.5 wt% solution A over 12 hours with stirring at 15 rpm, and the mixture reacted to form a gel at 22°C. Then, hexamethyldiamine bromide (HMBr2) and a 25 wt% aqueous solution of hexamethyldiammonium hydroxide (HM(OH)2) were added, and the mixture was stirred for 1 hour. The pH was then adjusted to 11.8 with an 18 wt% sodium hydroxide solution, and the mixture was aged at 22°C for 3 hours to obtain an initial gel. This initial gel was then transferred to a sealed stainless steel reaction vessel and pre-crystallized at 115°C for 5 hours under hydrothermal conditions, followed by crystallization at 185°C for 42 hours to obtain a crystallized product. The crystallized product was then cooled, filtered, washed, and dried to obtain the final solid product.

[0208] In the above, the molar ratio of the aqueous solution of isobutylene triethoxysilane, sodium aluminate, sodium hydroxide, hexamethyldiamine bromide (HMBr2), and hexamethyldiammonium hydroxide (HM(OH)2) to deionized water is 300:1:30:15:1600, wherein the mass ratio of the aqueous solution of hexamethyldiamine bromide (HMBr2) and hexamethyldiammonium hydroxide (HM(OH)2) is 1:8; the above isobutylene triethoxysilane contains structural units; the preparation of the isobutylene triethoxysilane containing structural units is the same as in Example 1.

[0209] The final solid product obtained was EU-1 molecular sieve KE23, which XRD analysis showed to have an EUO structure; the silicon-to-aluminum molar ratio in KE23 was 251.8, and the specific surface area S... BET 460m 2 / g, microporous specific surface area S micro 387m 2 / g, the relative crystallinity of the crystal is 75%, and the average grain size is 155nm.

[0210] Example 24

[0211] This embodiment provides an EU-1 molecular sieve with a high specific surface area, and the synthesis method is as follows:

[0212] Sodium aluminate (chemically pure, with an aluminum oxide content ≥41% and a sodium oxide content ≥31%, the same below) was dissolved in deionized water to obtain a 22.7 wt% solution A. Separately, ethyl silicate was dissolved in deionized water to obtain a 33.6 wt% solution B. This 33.6 wt% solution B was added dropwise to a 22.7 wt% solution A over 6 hours with stirring at 45 rpm, and the mixture reacted to form a gel at 22°C. Then, 25 wt% hexamethyldiammonium hydroxide (HM(OH)2) aqueous solution and hexamethyldiamine bromide (HMBr2) (Acros product, mass fraction >98%) were added. After stirring for 1 hour, the pH was adjusted to 13.0 with 25 wt% tetramethylammonium hydroxide aqueous solution, and the mixture was aged at 22°C for 3 hours to obtain an initial gel. The initial gel was then transferred to a sealed stainless steel reaction vessel and pre-crystallized at 80°C for 10 hours under hydrothermal conditions, followed by crystallization at 175°C for 72 hours to obtain a crystallized product. The crystallized product was then cooled, filtered, washed, and dried to obtain the final solid product.

[0213] In the above, the molar ratio of the ethyl silicate, sodium aluminate, tetramethylammonium hydroxide, hexamethyldiammonium hydroxide HM(OH)2 aqueous solution, hexamethyldiamine bromide HMBr2, and deionized water is 100:1:100:18:1800, wherein the mass ratio of hexamethyldiammonium hydroxide HM(OH)2 aqueous solution to hexamethyldiamine bromide HMBr2 is 4:1; the above ethyl silicate contains structural units; the preparation of the ethyl silicate containing structural units is the same as in Example 1.

[0214] The final solid product obtained was EU-1 molecular sieve KE24, which XRD analysis showed to have an EUO structure; the silicon-to-aluminum molar ratio in KE24 was 69.1, and the specific surface area S... BET 507m 2 / g, microporous specific surface area S micro 410m 2 / g, the relative crystallinity of the crystal is 89%, and the average grain size is 78nm.

[0215] Example 25

[0216] This embodiment provides an EU-1 molecular sieve with a high specific surface area, and the synthesis method is as follows:

[0217] Boehmite (alumina content 70.3%) was dissolved in deionized water to obtain a 23.1 wt% solution A. Ethyl silicate was dissolved in deionized water to obtain a 33.4 wt% solution B. The 33.4 wt% solution B was added dropwise to the 23.1 wt% solution A over 5 hours with stirring at 280 rpm, and the mixture reacted to form a gel at 22°C. Then, a 25 wt% aqueous solution of hexamethyldiammonium hydroxide (HM(OH)2) was added, and the mixture was stirred for 1 hour. The pH was then adjusted to 10.8 with a 12 wt% aqueous solution of sodium hydroxide, and the mixture was aged at 22°C for 3 hours to obtain an initial gel. This initial gel was then transferred to a sealed stainless steel reaction vessel and pre-crystallized at 95°C for 5 hours under hydrothermal conditions, followed by crystallization at 158°C for 72 hours to obtain a crystallized product. The crystallized product was then cooled, filtered, washed, and dried to obtain the final solid product.

[0218] In the above, the molar ratio of the ethyl silicate, boehmite, sodium hydroxide, hexamethyl diammonium hydroxide (HM(OH)2) aqueous solution and deionized water is 85:1:20:18:880; the ethyl silicate contains structural units; the preparation of the ethyl silicate containing structural units is the same as in Example 1.

[0219] The final solid product obtained was EU-1 molecular sieve KE25, which XRD analysis showed to have an EUO structure; the silicon-to-aluminum molar ratio in KE25 was 69.1, and the specific surface area S... BET 525m 2 / g, microporous specific surface area S micro 421m 2 / g, the relative crystallinity of the crystal is 88%, and the average grain size is 80nm.

[0220] Example 26

[0221] This embodiment provides an EU-1 molecular sieve with a high specific surface area, and the synthesis method is as follows:

[0222] Boehmite (alumina content 70.3%) was dissolved in deionized water to obtain a 24.2 wt% solution A. Isobutylenetriethoxysilane was dissolved in deionized water to obtain a 29.5 wt% solution B. The 29.5 wt% solution B was added dropwise to the 24.2 wt% solution A over 1.5 hours with stirring at 520 rpm, and the mixture reacted to form a gel at 22°C. Then, a 25 wt% aqueous solution of hexamethyldiammonium hydroxide (HM(OH)2) was added, and the mixture was stirred for 1 hour. The pH was then adjusted to 11.5 with a 25 wt% potassium hydroxide solution, and the mixture was aged at 22°C for 3 hours to obtain an initial gel. This initial gel was then transferred to a sealed stainless steel reaction vessel and pre-crystallized at 95°C for 5 hours under hydrothermal conditions, followed by crystallization at 166°C for 56 hours to obtain a crystallized product. The crystallized product was then cooled, filtered, washed, and dried to obtain the final solid product.

[0223] In the above, the molar ratio of isobutylene triethoxysilane, boehmite, potassium hydroxide, hexamethyl diammonium hydroxide HM(OH)2 aqueous solution and deionized water is 80:1:50:10:2000; the above isobutylene triethoxysilane contains structural units; the preparation of the isobutylene triethoxysilane containing structural units is the same as in Example 1.

[0224] The final solid product obtained was EU-1 molecular sieve KE26, which XRD analysis showed to have an EUO structure; the silicon-to-aluminum molar ratio in KE26 was 64.6, and the specific surface area S... BET 508m 2 / g, microporous specific surface area S micro 410m 2 / g, the relative crystallinity of the crystal is 78%, and the average grain size is 25nm.

[0225] Example 27

[0226] This embodiment provides an EU-1 molecular sieve with a high specific surface area, and the synthesis method is as follows:

[0227] Boehmite (alumina content 70.3%) was dissolved in deionized water to obtain a 23.6 wt% solution A. Ethyl silicate was dissolved in deionized water to obtain a 30.8 wt% solution B. The 30.8 wt% solution B was added dropwise to the 23.6 wt% solution A over 7.5 hours with stirring at 1200 rpm, and the mixture reacted to form a gel at 22°C. Then, a 25 wt% aqueous solution of hexamethyldiammonium hydroxide (HM(OH)2) was added, and the mixture was stirred for 1 hour. The pH was then adjusted to 12.5 with a 30 wt% aqueous solution of tetraethylammonium hydroxide, and the mixture was aged at 22°C for 3 hours to obtain an initial gel. This initial gel was then transferred to a sealed stainless steel reaction vessel and pre-crystallized at 95°C for 5 hours under hydrothermal conditions, followed by crystallization at 140°C for 144 hours to obtain a crystallized product. The crystallized product was then cooled, filtered, washed, and dried to obtain the final solid product.

[0228] In the above, the molar ratio of the ethyl silicate, boehmite, tetraethylammonium hydroxide, hexamethyl diammonium hydroxide (HM(OH)2) aqueous solution and deionized water is 90:1:12:12:900; the ethyl silicate contains structural units; the preparation of the ethyl silicate containing structural units is the same as in Example 1.

[0229] The final solid product obtained was EU-1 molecular sieve KE27, which XRD analysis showed to have an EUO structure; the silicon-to-aluminum molar ratio in KE27 was 72.1, and the specific surface area S... BET 456m 2 / g, microporous specific surface area S micro 381m 2 / g, the relative crystallinity of the crystals is 94%, and the average grain size is 67nm.

[0230] Example 28

[0231] This embodiment provides an EU-1 molecular sieve with a high specific surface area, and the synthesis method is as follows:

[0232] Boehmite (alumina content 70.3%) was dissolved in deionized water to obtain a 23.3 wt% solution A. Ethyl silicate was dissolved in deionized water to obtain a 31.4 wt% solution B. The 31.4 wt% solution B was added dropwise to the 23.3 wt% solution A over 150 min with stirring at 600 rpm, and the mixture reacted to form a gel at 22°C. Then, a 25 wt% hexamethyldiammonium hydroxide (HM(OH)2) aqueous solution was added, and the mixture was stirred for 1 h. The pH was then adjusted to 12.8 with a 15 wt% tetraethylammonium hydroxide aqueous solution, and the mixture was aged at 22°C for 3 h to obtain an initial gel. This initial gel was then transferred to a sealed stainless steel reaction vessel and pre-crystallized at 95°C for 5 h under hydrothermal conditions, followed by crystallization at 145°C for 108 h to obtain a crystallized product. The crystallized product was then cooled, filtered, washed, and dried to obtain the final solid product.

[0233] In the above, the molar ratio of the ethyl silicate, boehmite, tetraethylammonium hydroxide, hexamethyl diammonium hydroxide (HM(OH)2) aqueous solution and deionized water is 90:1:30:17:1000; the ethyl silicate contains structural units; the preparation of the ethyl silicate containing structural units is the same as in Example 1.

[0234] The final solid product obtained was EU-1 molecular sieve KE28, which XRD analysis showed to have an EUO structure; the silicon-to-aluminum molar ratio in KE28 was 68.1, and the specific surface area S... BET 423m 2 / g, microporous specific surface area S micro 375m 2 / g, the relative crystallinity of the crystals is 84%, and the average grain size is 70nm.

[0235] Example 29

[0236] This embodiment provides an EU-1 molecular sieve with a high specific surface area, and the synthesis method is as follows:

[0237] Boehmite (alumina content 70.3%) was dissolved in deionized water to obtain a 19.8 wt% solution A. Isobutylenetriethoxysilane was dissolved in deionized water to obtain a 31.6 wt% solution B. The 31.6 wt% solution B was added dropwise to the 19.8 wt% solution A over 10 hours with stirring at 60 rpm, and the mixture reacted to form a gel at 22°C. Then, a 25 wt% aqueous solution of hexamethyldiammonium hydroxide (HM(OH)2) was added, and the mixture was stirred for 1 hour. The pH was then adjusted to 11 with a 32 wt% sodium hydroxide solution, and the mixture was aged at 22°C for 3 hours to obtain an initial gel. This initial gel was then transferred to a sealed stainless steel reaction vessel and pre-crystallized at 95°C for 5 hours under hydrothermal conditions, followed by crystallization at 150°C for 96 hours to obtain a crystallized product. The crystallized product was then cooled, filtered, washed, and dried to obtain the final solid product.

[0238] In the above, the molar ratio of isobutylene triethoxysilane, boehmite, sodium hydroxide, hexamethyl diammonium hydroxide HM(OH)2 aqueous solution and deionized water is 80:1:160:20:2000; the above isobutylene triethoxysilane contains structural units; the preparation of the isobutylene triethoxysilane containing structural units is the same as in Example 1.

[0239] The final solid product obtained was EU-1 molecular sieve KE29, which XRD analysis showed to have an EUO structure; the silicon-to-aluminum molar ratio in KE29 was 67.8, and the specific surface area S... BET 438m 2 / g, microporous specific surface area S micro 370m 2 / g, the relative crystallinity of the crystals is 89%, and the average grain size is 220nm.

[0240] Example 30

[0241] This embodiment provides an EU-1 molecular sieve with a high specific surface area, and the synthesis method is as follows:

[0242] Boehmite (alumina content 70.3%) was dissolved in deionized water to obtain a 21.9 wt% solution A. Isobutylenetriethoxysilane was dissolved in deionized water to obtain a 31.7 wt% solution B. The 31.7 wt% solution B was added dropwise to the 21.9 wt% solution A over 5 hours with stirring at 330 rpm, and the mixture reacted to form a gel at 22°C. Then, a 25 wt% hexamethyldiammonium hydroxide (HM(OH)2) aqueous solution was added, and the mixture was stirred for 1 hour. The pH was then adjusted to 10.5 with a 5 wt% ammonia solution, and the mixture was aged at 22°C for 1.5 hours to obtain an initial gel. This initial gel was then transferred to a sealed stainless steel reaction vessel and pre-crystallized at 95°C for 5 hours under hydrothermal conditions, followed by crystallization at 155°C for 70 hours to obtain a crystallized product. The crystallized product was then cooled, filtered, washed, and dried to obtain the final solid product.

[0243] In the above, the molar ratio of isobutylene triethoxysilane, boehmite, ammonia, hexamethyl diammonium hydroxide HM(OH)2 aqueous solution and deionized water is 85:1:10:8:600; the above isobutylene triethoxysilane contains structural units; the preparation of the isobutylene triethoxysilane containing structural units is the same as in Example 1.

[0244] The final solid product obtained was EU-1 molecular sieve KE30, which XRD analysis showed to have an EUO structure; the silicon-to-aluminum molar ratio in KE30 was 69.1, and the specific surface area S0 was [missing information]. BET 477m 2 / g, microporous specific surface area S micro 407m 2 / g, the relative crystallinity of the crystals is 93%, and the average grain size is 120nm.

[0245] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. An EU-1 molecular sieve, characterized in that, The silica-alumina molar ratio of the EU-1 molecular sieve is 5–500, and the specific surface area S of the EU-1 molecular sieve is... BET 400m 2 / g~700m 2 / g, microporous specific surface area S micro 300m 2 / g~500m 2 / g, the relative crystallinity of the EU-1 molecular sieve is 75% to 99%, and the average particle size of the crystals in the EU-1 molecular sieve is 5nm to 300nm.

2. The EU-1 molecular sieve according to claim 1, characterized in that, The specific surface area S of the EU-1 molecular sieve BET 409m 2 / g~525m 2 / g, and / or microporous specific surface area S micro 350m 2 / g~421m 2 / g, and / or the relative crystallinity of the EU-1 nanomolecular sieve is greater than 85% to 99%; and / or the average particle size of the crystals in the EU-1 molecular sieve is 10nm to 200nm.

3. A method for synthesizing EU-1 molecular sieve as described in claim 1 or 2, characterized in that, The process includes the steps of mixing, aging, and crystallizing a silicon source, an aluminum source, an alkali source, a template agent, and solvent I to obtain EU-1 molecular sieve; the silicon source is selected from silicon sources containing structural units.

4. The synthesis method according to claim 3, characterized in that, In the ultraviolet Raman spectrum of the silicon source containing structural units, at a vibrational frequency of 240 cm⁻¹ -1 There is a characteristic peak nearby, with a vibration frequency not exceeding 600 cm⁻¹. -1 In the characteristic region, there exists at least one non-240 cm -1 The characteristic peaks nearby, and not at 240 cm⁻¹ -1 The total peak area of ​​the nearby characteristic peaks is no more than 600 cm². -1 The characteristic region and characteristic peak area account for 20% to 98% of the total area.

5. The synthesis method according to claim 3, characterized in that, The aluminum source is selected from at least one of aluminum sulfate, sodium aluminate, aluminum chloride, aluminum nitrate, and boehmite.

6. The synthesis method according to any one of claims 3-5, characterized in that, The alkali source is selected from at least one of ammonia, sodium hydroxide, potassium hydroxide, rubidium hydroxide, and tetraethylammonium hydroxide.

7. The synthesis method according to any one of claims 3-5, characterized in that, The template agent is selected from at least one of hexamethyldiammonium bromide, hexamethyldiammonium hydroxide aqueous solution or methanol solution, and template agent precursor.

8. The synthesis method according to claim 7, characterized in that, The template precursor is prepared by dissolving a dihaloalkane and a monoamine in an organic solvent.

9. The synthesis method according to claim 8, characterized in that, The dihaloalkane is 1,6-dibromohexane or 1-chloro-6-bromohexane.

10. The synthesis method according to claim 8, characterized in that, The monoamine is trimethylamine.

11. The synthesis method according to claim 8, characterized in that, The organic solvent is acetone.

12. The synthesis method according to claim 8, characterized in that, The molar ratio of the dihaloalkane, monoamine, and organic solvent is (1~50):(3~100):(5~50).

13. The synthesis method according to claim 7, characterized in that, The mass concentration of the aqueous or methanolic hexamethyl diammonium hydroxide solution is 1% to 40%.

14. The synthesis method according to claim 13, characterized in that, The mass concentration of the aqueous or methanolic hexamethyl diammonium hydroxide solution is 25%.

15. The synthesis method according to any one of claims 3-5, characterized in that, The solvent I is selected from at least one of water, methanol, ethanol, isopropanol, imidazole ionic liquid, and [bmim]PF6 anionic ionic liquid.

16. The synthesis method according to any one of claims 3-5, characterized in that, The initial gel mixture is obtained by mixing the silicon source, aluminum source, alkali source, template agent and solvent I.

17. The synthesis method according to claim 16, characterized in that, The molar ratio of the silicon source, aluminum source, alkali source, template agent and solvent I is (10~300):1:(0~300):(1~20):(20~2000).

18. The synthesis method according to claim 17, characterized in that, The molar ratio of the silicon source, aluminum source, alkali source, template agent and solvent I is (30~300):1:(0~100):(1~20):(20~2000).

19. The synthesis method according to any one of claims 3-5, characterized in that, The aging process is carried out at a temperature of 20℃ to 25℃ for a duration of 0h to 4h.

20. The synthesis method according to claim 19, characterized in that, The aging time is 0.5h to 4h.

21. The synthesis method according to any one of claims 3-5, characterized in that, The crystallization process employs a segmented crystallization procedure, including pre-crystallization and crystallization. And / or, the crystallization process may further include steps of cooling, washing, and drying.

22. The synthesis method according to claim 21, characterized in that, The precrystallization temperature is 30–120°C, and the precrystallization time is 0.5–12 h.

23. The synthesis method according to claim 22, characterized in that, The crystallization temperature is 120–200℃, and the crystallization time is 12h–500h.

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