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

Abstract

The invention discloses an EU-1 molecular sieve and a synthesis method thereof, and belongs to the field of EU-1 molecular sieves. According to the EU-1 molecular sieve disclosed by the invention, the specific surface area SBET of the EU-1 molecular sieve is greater than or equal to 400m < 2 > / g, and the micropore specific surface area Sm < 2 > is greater than or equal to 300m < 2 > / g; the synthesis method of the EU-1 molecular sieve comprises the following steps: mixing a silicon source, an aluminum source, an alkali source, a template agent and a solvent I, aging, and carrying out segmented crystallization to obtain the EU-1 molecular sieve, the silicon source is a silicon source containing a structural unit; according to the synthesis method of the EU-1 molecular sieve, disclosed by the invention, the EU-1 molecular sieve induced nucleation microcrystals can be modulated in a very wide range by controlling crystallization time and temperature, so that an EU-1 molecular sieve product with high specific surface area and high crystallinity is obtained; a silicon source containing a structural unit is used as a silicon source, the EU-1 molecular sieve can be rapidly prepared by regulating and controlling cations of a crystallization system, and the crystal grain morphology of the molecular sieve has the characteristics of uniformity and high dispersion.

Description

Technical Field

[0001] The invention relates to the field of EU-1 molecular sieve synthesis, and in particular to a EU-1 molecular sieve with a high specific surface area and a synthesis method thereof. Background Art

[0002] The development of high-performance molecular sieve materials is the key to improving catalytic performance. It is the result of the combined effect of pore structure and surface acid properties; among them, the pore structure and its parameters are crucial. The EU-1 molecular sieve, which belongs to the EUO topology, is a type of silicon-aluminum composite material with a one-dimensional pore structure and regular porosity, containing 10MR (ten-membered ring) straight microporous channels and 12MR (twelve-membered ring) side pocket structures vertically connected to it; the side pocket has a size of 0.68nm×0.58nm, which is interconnected with the outer surface of the crystal through the 10MR microporous channels, and the pore size is 0.41nm×0.58nm. The one-dimensional 10MR channel of the EU-1 molecular sieve and its side deep holes can form a special shape-selective effect. Due to the particularity of its pore structure, the application of the EU-1 molecular sieve in the field of petrochemicals has been widely studied. However, due to the one-dimensional pores of its crystals, the morphology of the synthesized EU-1 molecular sieve is usually shuttle-shaped crystals, and the crystal size is usually at the micron level. Therefore, the orderly connectivity of the micropores is poor, which limits the mass transfer diffusion and catalytic performance of the reaction molecules.

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

[0004] Catalysis, 1991, 65(9): 603-612). So far, the synthesis routes of EU-1 molecular sieve can be basically divided into two categories: hydrothermal method based on liquid phase transformation mechanism and dry gel method based on solid phase transformation mechanism. In these methods, a large amount of expensive and environmentally unfriendly organic templates must be added to the synthesis system (the molar ratio of template to system silicon oxide is greater than 0.2). These templates are usually highly toxic and expensive. At the same time, the production contains a high concentration of halogen bromine, and the production efficiency and economy of EU-1 molecular sieve are poor. European Union patent EP159845 discloses a method for synthesizing EUO structure molecular sieves using dimethylbenzene (DBDMA) as a template. U.S. Patent US2001 / 0051757A1 discloses a method for synthesizing a low silicon-aluminum ratio EUO structure molecular sieve, which uses diphenylmethyl dimethylamine or its precursor as a structure directing agent and adds at least one seed including an EUO type molecular sieve to the synthesis system. A reaction mixture formed by uniformly mixing a silicon source, an aluminum source, an alkali metal compound, a template agent and the seed is hydrothermally crystallized to obtain a EU-1 molecular sieve with a Si / Al molar ratio of 5 to 50. Summary of the invention

[0005] In order to overcome the problems of insufficient orderly connectivity of the one-dimensional composite micropores of the above-mentioned EU-1 molecular sieve product type, low pore regularity and long crystallization period of conventional EU-1 molecular sieves, the present invention provides a EU-1 molecular sieve with a high specific surface area and a synthesis method thereof.

[0006] In order to solve the above technical problems, the first aspect of the present invention provides a EU-1 molecular sieve, wherein the specific surface area S of the EU-1 molecular sieve is BET 400m 2 / g~700m 2 / g, micropore 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 crystallites 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 5-500, preferably 25-270.

[0008] According to some embodiments of the present invention, the specific surface area S of the EU-1 molecular sieve is BET 409m 2 / g~525m 2 / g, micropore 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 crystallites in the EU-1 molecular sieve is 10nm to 200nm, and it can be characterized and observed by high-resolution electron microscopy to have a clear crystal surface structure.

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

[0010] The 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 and a solvent I, aging and crystallizing to obtain the EU-1 molecular sieve; the silicon source is selected from a silicon source containing a structural unit;

[0011] In the ultraviolet Raman spectrum of the silicon source containing the structural unit, at the vibration frequency of 240cm -1There are characteristic peaks nearby, with a vibration frequency no greater than 600cm -1 In the characteristic area, there is at least one non-240cm -1 Characteristic peaks near 240cm -1 The sum of the peak areas of the nearby characteristic peaks is no more than 600 cm -1 The total area of ​​the characteristic peaks in the characteristic region is ≥ 20% but not more than 98% (correspondingly, at 240 cm -1 The area of ​​the characteristic peaks near the -1 The total area of ​​characteristic peaks in the characteristic region is ≤80%).

[0012] In some embodiments of the present invention, in the ultraviolet Raman spectrum of the silicon source containing the structural unit, at a vibration frequency of no more than 600 cm -1 In the characteristic region, there is a vibration frequency of 335cm -1 、400cm -1 and 480cm -1 At least one characteristic peak in the vicinity.

[0013] In the present invention, the peak area of ​​each characteristic peak can be obtained by automatic (or manual if necessary) integration in a spectrometer. The present invention does not limit the specific peak area of ​​each characteristic peak. -1 The peak area of ​​the characteristic peaks near 240 cm -1 The relationship between the areas of nearby characteristic peaks has corresponding limitations.

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

[0015] According to the present invention, 240cm -1 The characteristic peak near the silicon-containing eight-membered ring (8MR) is the characteristic signal of TOT bending vibration. When the ultraviolet Raman spectrum of the silicon source containing the structural unit is at 240cm -1 When there is a characteristic peak nearby, it means that the silicon atoms in the silicon source containing the structural unit have overcome the skeleton 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 the silicon source containing the structural unit, 240cm -1 The characteristic peaks near the 8-membered ring (8MR) represent the bending vibration of TOT in the silicon-containing 8-membered ring; the vibration frequency is not more than 600 cm -1 In the characteristic region, the smaller rings correspond to higher vibration frequencies, not 240 cm -1 Among the characteristic peaks nearby, 335cm -1、400cm -1 or 480cm -1 The characteristic peaks near 240cm represent the bending vibration of TOT in the six-membered ring (6MR), five-membered ring (5MR) and four-membered ring (4MR) containing silicon. -1 The sum of the peak areas of the nearby characteristic peaks is no more than 600 cm -1 The total area of ​​the characteristic peaks in the characteristic region is ≥20%, indicating that the silicon atoms in the silicon source containing the structural unit have more 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 the structural unit, at a vibration frequency of no more than 600 cm -1 In the characteristic area, non-240cm -1 The characteristic peak near is 335cm -1 、400cm -1 and 4480cm -1 At least one of the nearby characteristic peaks.

[0018] According to some embodiments of the present invention, at a vibration frequency of no more than 600 cm -1 In the characteristic area, non-240cm -1 The characteristic peak near 335cm -1 、400cm -1 and 480cm -1 The sum of the peak areas of at least one of the characteristic peaks nearby is no more than 600 cm -1 The total area of ​​characteristic peaks in the characteristic region is ≥50%.

[0019] Regarding the expression “near” in the above content, those skilled in the art will know that since each characteristic peak in the ultraviolet Raman spectrum usually has a displacement, the position of the characteristic peak defined in the present invention may have a deviation, such as 480cm -1 The nearby characteristic peak is at 450cm -1 ~500cm -1 However, the vibration represented by each characteristic peak can be determined by those skilled in the art.

[0020] In the present invention, the above-mentioned “no more than 600cm -1 The characteristic area generally refers to 0cm -1 ~600cm -1 (e.g. 150cm -1 ~600cm -1) in the ultraviolet Raman spectrum region. Those skilled in the art will understand that if a characteristic peak appears in a region where the characteristic peak is not easy to appear in the silicon source containing the structural unit, 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 the structural unit is 200m 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 the structural unit, the mass fraction of SiO2 is >90%, preferably >95%, and further 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 cm 3 / g~3.0cm 3 / g.

[0024] The method for preparing the silicon source containing the structural unit comprises the following steps:

[0025] S1, providing a mixed solution I containing a treatment reagent and a solvent II;

[0026] S2, mixing the silicon-containing raw material with the mixed solution I to obtain a mixed solution II;

[0027] S3, performing activation treatment on the mixed solution II to obtain an activated product;

[0028] S4, calcining the activated product to obtain the silicon source containing the structural unit.

[0029] According to some embodiments of the present invention, in step S1, the treatment reagent is selected from at least one of an inorganic base, a fluorine-containing substance, an organic base and an ionic liquid containing an organic anion; preferably at least one of ammonia water, 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 the present invention, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) is an imidazole-type ionic liquid.

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

[0032] In the present invention, when used, the treatment reagent is usually prepared into a solution of a certain concentration using water or alcohol as a solvent. For example, the organic base can be prepared into an aqueous solution or an alcohol solution. Those skilled in the art can make a selection based on actual conditions.

[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) silica sol, white carbon black, gas-phase silica sol, silicon powder, silicone resin microspheres, silicates (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, isobutylene triethoxysilane, trichlorosilane SiHCl3 and tetraethoxysilane Si(OC2H5)4.

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

[0036] In the present invention, the optional silicon-containing raw materials mentioned above are all silicon-containing materials 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 the solvent II to SiO2 in the silicon-containing raw material (hereinafter referred to as the 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 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 the mixing treatment 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 process for performing the activation treatment (also referred to as the gelling process) is selected from The method comprises at least one of the following steps: preparing monodisperse SiO2 microspheres by alkaline hydrolysis of tetraethyl orthosilicate (TEOS), hydrolysis, oligomer precipitation, alkaline dissolution and hot melting to highlight the mineralization effect on silicon atoms.

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

[0043] In the present invention, the activation treatment preferably uses an optimized Specifically, the hydrolysis, bonding and SiO2 growth rates can be controlled by the amount of solvent, temperature and stirring speed to achieve uniformity and controllability of silicon powder.

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

[0045] According to some embodiments of the present invention, the conditions for the activation treatment include: a temperature not higher than 200°C (such as 0-200°C), preferably not higher than 100°C (such as 0-100°C); a treatment time of 1 hour to 500 days, preferably 12 hours to 12 days. Further preferably, the activation treatment is completed at a temperature of 0-10°C, a temperature of 10-30°C, a temperature of 30-80°C, and a temperature of 80-100°C (staged constant temperature heat treatment) for 0 to 120 hours (such as 1 to 120 hours).

[0046] According to some embodiments of the present invention, after obtaining the activated product of step S3, before performing the calcination treatment of step S4, the activated product may be subjected to impurity removal treatment, and water-soluble impurities and solvents, including all impurities specifically present such as physically adsorbed water, alcohols, salts and ionic liquids, may be removed by means of forced air drying, vacuuming, etc. At the same time, a maximum of Si, C, H, O, F, S, Br, Cl or MoO x At least one composition.

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

[0048] According to some embodiments of the present invention, during the calcination treatment, 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 the present invention, the calcination treatment is used to remove the skeleton crystal water (the desorption temperature is usually ≥ 200°C at normal pressure), sublimable fluoride, sulfur or MoO x Impurities such as alkali or salt molecules of the organic template 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 pseudo-boehmite.

[0051] According to some embodiments of the present invention, the alkaline source is selected from at least one of ammonia water, 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 hexamethonium bromide, an aqueous solution or methanol solution of hexamethonium hydroxide, and a template agent precursor; preferably, the template agent precursor is prepared by dissolving a dihalogenated alkane and a monoamine in an organic solvent; preferably, the dihalogenated alkane 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 dihalogenated alkane, the monoamine and the organic solvent is: (1-50): (3-100): (5-50); further preferably, the mass concentration of the aqueous solution or methanol solution of hexamethonium hydroxide 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-type ionic liquids, and [bmim]PF6 anionic ionic liquids.

[0054] According to some embodiments of the present invention, the silicon source, the aluminum source, the alkali source, the template and the solvent I are mixed to obtain an initial gel mixture; preferably, the molar ratio of the silicon source, the aluminum source, the alkali source, the template and the solvent I is (10-300):1:(0-300):(1-20):(20-2000), 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 0 h to 4 h, preferably 0.5 h to 4 h.

[0056] In the present invention, the cations (including inorganic alkali metal ions and organic quaternary ammonium ions) of the crystallization system, that is, the molar ratio of the template to the alkali source is critical. In the technical scheme of the present invention, the proportion of cations is appropriately controlled in the stage of segmented crystallization of the EU-1 molecular sieve to obtain fine EU-1 molecular sieve microcrystals containing a large amount of incomplete crystallization, and then hydrothermal crystallization is carried out according to the traditional high-temperature method to induce nucleation and increase the crystallization rate. The grain size of the obtained product EU-1 molecular sieve can even be significantly reduced to less than one tenth of the size of the product synthesized by the conventional method.

[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°C to 120°C, and the pre-crystallization time is 0.5h to 12h; further preferably, the crystallization temperature is 120°C to 200°C, and the crystallization time is 12h to 500h;

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

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

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

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

[0062] 3) Add solution B dropwise to solution A under stirring to react and form a gel;

[0063] 4) adding a template to the gel obtained in step 3), stirring for 1 h to 2 h, adjusting the pH to 10 to 14, and stirring again to obtain an initial gel;

[0064] 5) The initial gel obtained in step 4) is transferred into a reaction tank crystallization kettle and sealed, and pre-crystallized at a temperature of 30°C to 120°C for 0.5h to 12h, and then hydrothermally crystallized at a temperature of 120°C to 200°C for 12h to 500h. The resulting crystallized product is cooled, filtered, washed, and dried to obtain a final solid product, namely 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] The present invention relates to an EU-1 molecular sieve with a high specific surface area and a synthesis method thereof. By using a silicon source containing structural units as a silicon source, a highly regular EU-1 molecular sieve can be obtained by segmented hydrothermal crystallization in less than three days. It is generally believed that crystal growth must go through the process of nucleation, growth and growth cessation. Under the same crystallization conditions, the more crystal nuclei the crystallization system can provide, the faster its crystallization rate is, so it is easier to generate nanocrystals with smaller particle size and higher relative crystallinity. The segmented crystallization strategy has guiding activity because, through the low-temperature induction process, the crystallization system contains extremely small crystal nuclei with a certain crystal structure, and its existence is the fundamental reason for accelerating the rapid growth of crystals. Compared with the relatively low-temperature stage induced crystallization, the crystal nuclei of the molecular sieve are already contained. Since the crystal nucleus particles are very small and dispersed very evenly in the synthetic reaction mixture, they have a good structural guiding effect. The technical solution of the present invention better solves the problem of orderly connectivity of the micropore channels of the one-dimensional EU-1 molecular sieve. The obtained EU-1 molecular sieve has the characteristics of high crystallinity and high specific surface area. The diffraction spots are clear through SAED characterization, and the specific surface area S BET ≥400m 2 / g, and the micropore specific surface area S micro ≥300m 2 / g, showing excellent mass transfer and diffusion performance for reaction molecules.

[0067] Beneficial effects:

[0068] The synthesis method of the EU-1 molecular sieve with a high specific surface area of ​​the present invention has two obvious advantages. First, the EU-1 molecular sieve induced nucleation microcrystals can be adjusted in a wide range by controlling the crystallization time and temperature, thereby obtaining a EU-1 molecular sieve product with a high specific surface area and high crystallinity (relative crystallinity greater than 85%); second, a silicon source containing a structural unit is used as a silicon source, and the EU-1 molecular sieve can be quickly prepared by regulating the cations (including inorganic alkali metal ions and organic quaternary ammonium ions) of the crystallization system, that is, the molar ratio of the template to the alkali source. The molecular sieve grain morphology is characterized by high-resolution electron microscopy and is characterized by uniform and high dispersion, and a single crystal has a clear crystal plane structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 XRD spectra of EU-1 molecular sieves prepared in Examples 1, 2, and 3 of the present invention;

[0070] Figure 2 This is a HR-TEM photo of the EU-1 molecular sieve prepared in Example 1 of the present invention;

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

[0072] Figure 4 The crystallization kinetic curves of EU-1 molecular sieves prepared in Example 1 and Comparative Example 1 of the present invention;

[0073] Figure 5 This is a TEM photo of the silicon source SG1 containing the structural unit prepared in Example 1 of the present invention;

[0074] Figure 6 UV-Raman spectra of silicon source SG1 and white carbon black A200 containing structural units prepared in Example 1 of the present invention;

[0075] Figure 7 The nitrogen low temperature adsorption-desorption (BET) curves of the silicon source SG1 and white carbon black A200 containing the structural unit prepared in Example 1 of the present invention;

[0076] Figure 8 FT-IR spectra of the silicon source SG1 and white carbon black A200 containing structural units prepared in Example 1 of the present invention. DETAILED DESCRIPTION

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

[0078] The specific surface area S of the EU-1 molecular sieve in the present invention is BET , micropore specific surface area S micro The specific surface area S of the sample was determined by using a Tristar3000 surface area analyzer produced by Micrometrics for low-temperature N2 adsorption-desorption analysis. The sample was pretreated with vacuum activation at 300°C for 6 hours before testing. The test temperature was -196°C. The specific surface area S of the test sample was obtained by analyzing the isotherm. BET , micropore specific surface area S micro And other structural data.

[0079] The phase analysis (XRD test) of the present invention adopts the D8 Focus diffractometer of Bruker Company, a graphite monochromator, a Cu target Kα ray light source, a wavelength λ of 0.154nm, a tube voltage of 40kV, a tube current of 40mA, and records the diffraction signal in the 2θ range of 3 to 90° (scanning speed of 2° / min), and estimates the relative crystallinity based on the characteristic peak area (EU-1 molecular sieve has a 2θ range of 8.0°, 8.7°, 9.1°, 19.1°, 20.6°, 22.2°, 23.4°, 24. At 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 topological structure. The sum of the above characteristic peak areas and the ratio of the sum of the above characteristic peak areas to the sum of the above characteristic peak areas 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) photos and SAED diffraction spot images in the present invention are all taken using a Nova Nano SEM 450 microscope from FEI Company;

[0081] In the present invention, XRD is used to analyze the relative crystallinity of EU-1 molecular sieves obtained at different crystallization times, and the crystallization kinetic curve of EU-1 molecular sieve under corresponding synthesis conditions is obtained;

[0082] In the present invention, the specific surface area and pore volume of the silicon source containing the structural unit are analyzed by low-temperature N2 adsorption-desorption analysis of the sample using a Tristar3000 specific surface analyzer produced by Micrometrics. The sample is pretreated at 300°C for 6 hours by vacuum activation before testing. The test temperature is -196°C. The pore structure data such as the specific surface area and pore volume of the test sample are obtained by analyzing the isotherm.

[0083] In the present invention, the mass fraction of SiO2 in the silicon source containing the structural unit is measured by thermogravimetric TG-DTA analysis of the sample using a TGA Q500analyzer instrument (test conditions are air atmosphere, heating rate 10°C / min).

[0084] In the present invention, the FT-IR spectrum test uses a Nexus670 Fourier transform infrared spectrometer (FT-IR) produced by Nicolet Company of the United States to analyze the skeleton vibration area of ​​the sample; during the test, the sample powder is first diluted with KBr to a mass fraction of about 3%, ground and mixed evenly with a mortar, and then pressed into a tablet to prepare a sample, which is then placed in a vacuum cell for testing, and the test resolution is 4cm- 1 , scanning times 32 times, test range 400~4000cm-1 .

[0085] In the following examples, all chemical reagents used are commercially available products and, unless otherwise specified, have not been specially purified.

[0086] Example 1

[0087] This embodiment provides a 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 20.5wt% solution A. Methyltrimethoxysilane was dissolved in deionized water to obtain 32.1wt% solution B. The 32.1wt% solution B was added dropwise to the 20.5wt% solution A within 30min under stirring at a rate of 50rpm and mixed to form a gel at 20°C. Then, 25wt% hexamethylammonium hydroxide HM(OH)2 methanol solution was added and stirred for 2h. The pH value was adjusted to 12 by using 40wt% sodium hydroxide aqueous solution, and the solution was allowed to stand for aging at 25°C for 2h to obtain an initial gel. The initial gel was then transferred into a stainless steel reaction tank and sealed. After pre-crystallization at a hydrothermal temperature of 120°C for 2h, the solution was taken out and re-introduced into a hydrothermal temperature of 175°C for crystallization for 48h to obtain a crystallized product. The crystallized product was cooled, filtered, washed, and dried to obtain a final solid product.

[0089] The final solid product obtained is EU-1 molecular sieve KE1. XRD test shows that it has EUO structure. The XRD test of KE1 is shown in the attached Figure 1 ; The molar ratio of silicon to aluminum in KE1 is 55, and the specific surface area S BET 438m 2 / g, micropore specific surface area S micro 372m 2 / g, the relative crystallinity of the crystals is 89%, and the average particle size of the grains is 30nm.

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

[0091] The solid block obtained in the above preparation was treated with 1% citric acid aqueous solution at a liquid-solid mass ratio of about 6:1, and then acid exchanged and activated at 80°C for 1.5 hours, washed with deionized water until electrically neutral, and dried at 120°C. The temperature was then raised to 600°C at a rate of 3°C / min, and calcined at a constant temperature for 1.5 hours to obtain methyltrimethoxysilane containing a structural unit, which was counted as sample SG1.

[0092] The specific surface area of ​​sample SG1 is S BET 510m 2 / g, pore volume = 2.4 cm 3 / g, SiO2 mass fraction is 99%, Figure 6 It can be seen that compared with silica A200, sample SG1 has a vibration frequency of no more than 600 cm -1 There are more non-240cm areas in the characteristic area -1 Nearby characteristic peaks; UV-Raman detected its vibration frequency at 335cm -1 、400cm -1 and 4480cm -1 The peak area of ​​the characteristic peak near 240cm -1 The characteristic peaks near 240cm -1 The sum of the peak areas of the nearby characteristic peaks is no more than 600 cm -1 The total area of ​​characteristic peaks in the characteristic region is 78%. Figure 6 In the UV-Raman spectrum of sample SG1, due to peak overlap, 335cm -1 、400cm -1 and 480cm -1 Nearby characteristic peaks overlap.

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

[0094] Example 2

[0095] This embodiment provides a 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 22.5wt% solution A. Hexamethyldisilazane was dissolved in deionized water to obtain 33.0wt% solution B. The 33.0wt% solution B was added dropwise to the 22.5wt% solution A within 2 hours under stirring at 200rpm and reacted to form gel at 25°C. Hexamethyldiamine bromide HMBr2 and 25wt% hexamethyldiamine hydroxide HM(OH)2 ethanol solution were added and stirred for 1.5 hours. The pH value was adjusted to 12.5 with 30wt% tetraethylammonium hydroxide aqueous solution, and then aged for 2 hours at 25°C to obtain an initial gel. The initial gel was then transferred into a stainless steel reaction tank and sealed. After pre-crystallization at 100°C hydrothermal conditions for 6 hours, the gel was taken out and re-introduced into 185°C hydrothermal conditions for crystallization for 24 hours to obtain a crystallized product. The crystallized product was cooled, filtered, washed, and dried to obtain a final solid product.

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

[0098] The final solid product obtained is EU-1 molecular sieve KE2. XRD test shows that it has EUO structure. The XRD test of KE2 is shown in the attached Figure 1 ; The molar ratio of silicon to aluminum in KE2 is 1:12, and the specific surface area S BET 417m 2 / g, micropore specific surface area S micro 355m 2 / g, the relative crystallinity of the crystals is 95%, and the average particle size of the grains is 18nm.

[0099] Comparative Example 1

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

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

[0102] The final solid product obtained is EU-1 molecular sieve DE1, and XRD test shows that it has EUO structure; the silicon-aluminum molar ratio in DE1 is 37, and the specific surface area S BET 298m 2 / g, micropore specific surface area S micro 230m 2 / g, the relative crystallinity of the crystals is 87%, and the average particle size of the grains is 35nm.

[0103] Comparative Example 2

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

[0105] The initial gel was prepared according to the synthesis method of Example 2, except that the initial gel was directly crystallized under hydrothermal conditions at a temperature of 180° C. for 24 h without pre-crystallization to induce nucleation.

[0106] The final solid product obtained is EU-1 molecular sieve DE2, and XRD test shows that it has EUO structure; the silicon-aluminum molar ratio in DE2 is 49, and the specific surface area is S BET 368m 2 / g, micropore specific surface area S micro 297m 2 / g, the relative crystallinity of the crystals is 79%, and the average particle size of the grains is 66nm.

[0107] Comparative Example 3

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

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

[0110] The final solid product obtained is EU-1 molecular sieve DE3. XRD test shows that it has EUO structure and the morphology is a conventional approximately ellipsoidal morphology. The silicon-aluminum molar ratio in DE3 is 53, and the specific surface area S BET 345m2 / g, micropore specific surface area S micro 286m 2 / g, the relative crystallinity of the crystals is 85%, and the average particle size of the grains is 55nm.

[0111] In order to further illustrate the improvement of EU-1 molecular sieve KE1 prepared in Example 1 of the present invention compared with EU-1 molecular sieve DE1 prepared in Comparative Example 1, as shown in Figure 4 It is the crystallization kinetic curve of Example 1 and Comparative Example 1. The crystallization behaviors 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 respectively, 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 the present invention, the relative crystallinity of EU-1 molecular sieves obtained at different crystallization times was analyzed by XRD, and the crystallization kinetic curve of EU-1 molecular sieve under corresponding synthesis conditions was obtained;

[0112] Depend on Figure 4 It can be seen that different silicon sources have an important influence on the induction period and growth crystallization behavior of EU-1 molecular sieve crystallization: In Comparative Example 1, the induction period of using gas phase silica sol A200 as the silicon source is relatively long, and crystallization begins to occur around 48 hours, which is consistent with the characteristics of EU-1 molecular sieve's one-dimensional composite pores that are not easy to nucleate and have a long crystallization cycle. After 120 hours, its crystallization growth curve slows down. Obviously, in Example 1 of the present invention, a silicon source containing a structural unit is used as the silicon source, and the induction period is significantly shortened. At 48 hours of crystallization, the degree of crystallinity has reached more than 80%; this is mainly due to the Si-O bond length. Smaller than Al-O bond length OSDA cation and AlO4 - There are differences in the interactions. The five-coordinate aluminum with weaker bond energy can be connected to each other through hydroxyl Al-O bonds, dehydroxylated and induce a topological transformation to four-coordinate. As the silicon-aluminum ratio increases, the unit cell shrinks, which shortens the induction period and crystallization period. A high silicon-aluminum ratio is more conducive to nucleation.

[0113] The above-mentioned EU-1 molecular sieve crystallization kinetics process conforms to the synergistic crystallization mechanism and its crystal growth theory: the silicon source containing structural units is rich in structural units (TOT molecular sieve framework structural units such as four-membered rings, five-membered rings or six-membered rings), and these structural units form polyhedrons under the structural guidance of hydrated cations 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 regular microporous structures and uniform and highly dispersed molecular sieve crystals.

[0114] Further, in Comparative Examples 1-3, the EU-1 structure molecular sieve synthesized by using gas phase silica sol product A200 as silicon source, without pre-crystallization induced nucleation, and without regulating the cation of crystallization system, the product or morphology is uneven, non-highly dispersed agglomeration, or the specific surface area and micropore crystallinity are poor, and the ordered permeability of the molecular sieve pore structure is obviously insufficient. In sharp contrast, in Examples 1-2 of the present invention, the grain size of the product molecular sieve can be effectively controlled by adjusting the alkalinity of the system and performing segmented crystallization. It can be seen that the silicon source containing structural units and segmented crystallization induced nucleation are very effective in reducing the grain size. At the same time, the cation regulation of the crystallization system effectively improves the uniformity, high dispersion, and crystallinity of the product grain morphology, and has high crystallinity and regular micropore channels, achieving good technical effects.

[0115] Example 3

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

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

[0118] The final solid product obtained is EU-1 molecular sieve KE3, and XRD test shows that it has EUO structure. Figure 1 The silicon-aluminum molar ratio in KE3 is 54.5.

[0119] Example 4

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

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

[0122] The final solid product obtained is EU-1 molecular sieve KE4, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE4 is 57.

[0123] Example 5

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

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

[0126] The final solid product obtained is EU-1 molecular sieve KE5, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE5 is 56.8.

[0127] Example 6

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

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

[0130] The final solid product obtained is EU-1 molecular sieve KE6, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE6 is 54.7.

[0131] Example 7

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

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

[0134] The final solid product obtained is EU-1 molecular sieve KE7, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE7 is 52.5.

[0135] Example 8

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

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

[0138] The final solid product obtained is EU-1 molecular sieve KE8, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE8 is 51.3.

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

[0140] Table 1

[0141]

[0142] Example 9

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

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

[0145] The final solid product obtained is EU-1 molecular sieve KE9, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE9 is 28.

[0146] Example 10

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

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

[0149] The final solid product obtained is EU-1 molecular sieve KE10, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE10 is 46.

[0150] Embodiment 11

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

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

[0153] The final solid product obtained is EU-1 molecular sieve KE11, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE11 is 59.

[0154] Example 12

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

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

[0157] The final solid product obtained is EU-1 molecular sieve KE12, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE12 is 73.

[0158] Example 13

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

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

[0161] The final solid product obtained is EU-1 molecular sieve KE13, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE13 is 87.5.

[0162] Embodiment 14

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

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

[0165] The final solid product obtained is EU-1 molecular sieve KE14, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE14 is 109.

[0166] Embodiment 15

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

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

[0169] The final solid product obtained is EU-1 molecular sieve KE15, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE15 is 129.

[0170] Example 16

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

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

[0173] The final solid product obtained is EU-1 molecular sieve KE16, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE16 is 157.

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

[0175] Table 2

[0176]

[0177] Embodiment 17

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

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

[0180] The final solid product obtained is EU-1 molecular sieve KE17, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE17 is 54.

[0181] Embodiment 18

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

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

[0184] The final solid product obtained is EU-1 molecular sieve KE18, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE18 is 56.

[0185] Embodiment 19

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

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

[0188] The final solid product obtained is EU-1 molecular sieve KE19, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE19 is 56.5.

[0189] Embodiment 20

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

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

[0192] The final solid product obtained is EU-1 molecular sieve KE20, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE20 is 55.

[0193] Embodiment 21

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

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

[0196] The final solid product obtained is EU-1 molecular sieve KE21, and XRD test shows that it has an EUO structure; the silicon-aluminum molar ratio in KE21 is 51.8.

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

[0198] Table 3

[0199]

[0200] Embodiment 22

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

[0202] Sodium aluminate (chemically pure, with alumina mass content of ≥41%, sodium oxide mass content of ≥31%, the same below) was dissolved in deionized water to obtain 23.0wt% solution A. Isobutylene triethoxysilane was also dissolved in deionized water to obtain 31.9wt% solution B, which was added dropwise to 23.0wt% solution A within 40min under stirring at a rate of 20rpm and reacted to form gel at a temperature of 22°C, and then 25wt% hexamethylammonium hydroxide HM(OH)2 aqueous solution was added, stirred for 1h, and the pH value was adjusted to 12.2 with 13wt% potassium hydroxide aqueous solution, and then aged for 3h at a temperature of 22°C to obtain an initial gel, and then the initial gel was transferred into a stainless steel reaction tank and sealed, pre-crystallized under a hydrothermal condition of a temperature of 120°C for 4h, and then crystallized under a hydrothermal condition of a temperature of 180°C for 48h to obtain a crystallized product, and the crystallized product was cooled, filtered, washed, and dried to obtain a final solid product.

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

[0204] The final solid product obtained is EU-1 molecular sieve KE22, and XRD test shows that it has EUO structure; the silicon-aluminum molar ratio in KE22 is 52.8, and the specific surface area S BET 427m 2 / g, micropore specific surface area S micro 355m 2 / g, the relative crystallinity of the crystals is 99%, and the average particle size of the grains is 11nm.

[0205] Embodiment 23

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

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

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

[0209] The final solid product obtained is EU-1 molecular sieve KE23, and XRD test shows that it has EUO structure; the silicon-aluminum molar ratio in KE23 is 251.8, and the specific surface area S BET 460m 2 / g, micropore specific surface area S micro 387m 2 / g, the relative crystallinity of the crystals is 75%, and the average particle size of the grains is 155nm.

[0210] Embodiment 24

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

[0212] Sodium aluminate (chemically pure, aluminum oxide content ≥41% by weight, sodium oxide content ≥31% by weight, 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, which was added dropwise to a 22.7 wt% solution A within 6 hours under stirring at a rate of 45 rpm and reacted to form a gel at a temperature of 22° C. Then, a 25 wt% aqueous solution of hexamethylammonium hydroxide HM(OH)2 and a hexamethylammonium bromide HMBr2 (Acros product, mass fraction>98%) were added. After stirring for 1 hour, the pH value was adjusted to 13.0 with a 25 wt% aqueous solution of tetramethylammonium hydroxide, and the mixture was aged for 3 hours at a temperature of 22° C. to obtain an initial gel. The initial gel was then transferred into a stainless steel reaction tank and sealed. After pre-crystallization at a hydrothermal temperature of 80° C. for 10 hours, the mixture was crystallized at a hydrothermal temperature of 175° C. for 72 hours to obtain a crystallized product. The crystallized product was cooled, filtered, washed, and dried to obtain a final solid product.

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

[0214] The final solid product obtained is EU-1 molecular sieve KE24, and XRD test shows that it has EUO structure; the silicon-aluminum molar ratio in KE24 is 69.1, and the specific surface area S BET 507m 2 / g, micropore specific surface area S micro 410m 2 / g, the relative crystallinity of the crystals is 89%, and the average particle size of the grains is 78nm.

[0215] Embodiment 25

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

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

[0218] In the above, the molar ratio of the ethyl silicate, pseudo-boehmite, sodium hydroxide, hexamethylammonium hydroxide HM(OH)2 aqueous solution and deionized water is 85:1:20:18:880); the ethyl silicate contains a structural unit; the ethyl silicate containing the structural unit is prepared in the same way as in Example 1.

[0219] The final solid product obtained is EU-1 molecular sieve KE25, and XRD test shows that it has EUO structure; the silicon-aluminum molar ratio in KE25 is 69.1, and the specific surface area S BET 525m 2 / g, micropore specific surface area S micro 421m 2 / g, the relative crystallinity of the crystals is 88%, and the average particle size of the grains is 80nm.

[0220] Embodiment 26

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

[0222] Pseudo-boehmite (alumina mass content 70.3%) was dissolved in deionized water to obtain 24.2wt% solution A. Isobutylene triethoxysilane was dissolved in deionized water to obtain 29.5wt% solution B. The 29.5wt% solution B was added dropwise to the 24.2wt% solution A within 1.5h under stirring at a rate of 520rpm and reacted to form gel at a temperature of 22°C. A 25wt% aqueous solution of hexamethylammonium hydroxide HM(OH)2 was then added and stirred for 1h. The pH value was adjusted to 11.5 with a 25wt% potassium hydroxide solution. The mixture was aged for 3h at a temperature of 22°C to obtain an initial gel. The initial gel was then transferred into a stainless steel reaction tank and sealed. After pre-crystallization at a hydrothermal temperature of 95°C for 5h, the mixture was crystallized at a hydrothermal temperature of 166°C for 56h to obtain a crystallized product. The crystallized product was cooled, filtered, washed, and dried to obtain a final solid product.

[0223] In the above, the molar ratio of the isobutylene triethoxysilane, pseudoboehmite, potassium hydroxide, hexamethylammonium hydroxide HM(OH)2 aqueous solution and deionized water is 80:1:50:10:2000; the above isobutylene triethoxysilane contains a structural unit; the isobutylene triethoxysilane containing the structural unit is prepared in the same way as in Example 1.

[0224] The final solid product obtained is EU-1 molecular sieve KE26, and XRD test shows that it has EUO structure; the silicon-aluminum molar ratio in KE26 is 64.6, and the specific surface area S BET 508m 2 / g, micropore specific surface area S micro 410m 2 / g, the relative crystallinity of the crystals is 78%, and the average particle size of the grains is 25nm.

[0225] Embodiment 27

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

[0227] Pseudo-boehmite (alumina mass content 70.3%) was dissolved in deionized water to obtain 23.6wt% solution A. Ethyl silicate was dissolved in deionized water to obtain 30.8wt% solution B. The 30.8wt% solution B was added dropwise to the 23.6wt% solution A within 7.5h under stirring at a rate of 1200rpm and reacted to form a gel at a temperature of 22°C. A 25wt% aqueous solution of hexamethylammonium hydroxide HM(OH)2 was then added and stirred for 1h. The pH value was adjusted to 12.5 with a 30wt% aqueous solution of tetraethylammonium hydroxide, and the mixture was aged for 3h at a temperature of 22°C to obtain an initial gel. The initial gel was then transferred into a stainless steel reaction tank and sealed. After pre-crystallization at a hydrothermal temperature of 95°C for 5h, the mixture was crystallized at a hydrothermal temperature of 140°C for 144h to obtain a crystallized product. The crystallized product was cooled, filtered, washed, and dried to obtain a final solid product.

[0228] In the above, the molar ratio of the ethyl silicate, pseudo-boehmite, tetraethylammonium hydroxide, hexamethylammonium hydroxide HM(OH)2 aqueous solution and deionized water is 90:1:12:12:900); the ethyl silicate contains a structural unit; the ethyl silicate containing the structural unit is prepared in the same way as in Example 1.

[0229] The final solid product obtained is EU-1 molecular sieve KE27, and XRD test shows that it has EUO structure; the silicon-aluminum molar ratio in KE27 is 72.1, and the specific surface area S BET 456m 2 / g, micropore specific surface area S micro 381m 2 / g, the relative crystallinity of the crystals is 94%, and the average particle size of the grains is 67nm.

[0230] Embodiment 28

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

[0232] Pseudo-boehmite (alumina mass content 70.3%) was dissolved in deionized water to obtain 23.3wt% solution A. Ethyl silicate was dissolved in deionized water to obtain 31.4wt% solution B. The 31.4wt% solution B was added dropwise to the 23.3wt% solution A within 150min under stirring at a rate of 600rpm and reacted to form a gel at a temperature of 22°C. A 25wt% aqueous solution of hexamethylammonium hydroxide HM(OH)2 was then added. After stirring for 1h, the pH value was adjusted to 12.8 with a 15wt% aqueous solution of tetraethylammonium hydroxide. The mixture was aged for 3h at a temperature of 22°C to obtain an initial gel. The initial gel was then transferred into a stainless steel reaction tank and sealed. After pre-crystallization at a hydrothermal temperature of 95°C for 5h, the mixture was crystallized at a hydrothermal temperature of 145°C for 108h to obtain a crystallized product. The crystallized product was cooled, filtered, washed, and dried to obtain a final solid product.

[0233] In the above, the molar ratio of the ethyl silicate, pseudo-boehmite, tetraethylammonium hydroxide, hexamethylammonium hydroxide HM(OH)2 aqueous solution and deionized water is 90:1:30:17:1000); the ethyl silicate contains a structural unit; the ethyl silicate containing the structural unit is prepared in the same way as in Example 1.

[0234] The final solid product obtained is EU-1 molecular sieve KE28, and XRD test shows that it has EUO structure; the molar ratio of silicon to aluminum in KE28 is 68.1, and the specific surface area S BET 423m 2 / g, micropore specific surface area S micro 375m 2 / g, the relative crystallinity of the crystals is 84%, and the average particle size of the grains is 70nm.

[0235] Embodiment 29

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

[0237] Pseudo-boehmite (alumina mass content 70.3%) was dissolved in deionized water to obtain 19.8wt% solution A. Isobutylene triethoxysilane was dissolved in deionized water to obtain 31.6wt% solution B. The 31.6wt% solution B was added dropwise to the 19.8wt% solution A within 10 hours under stirring at a rate of 60rpm and reacted to form a gel at a temperature of 22°C. A 25wt% aqueous solution of hexamethylammonium hydroxide HM(OH)2 was then added. After stirring for 1 hour, the pH value was adjusted to 11 with a 32wt% sodium hydroxide solution. The mixture was aged for 3 hours at a temperature of 22°C to obtain an initial gel. The initial gel was then transferred into a stainless steel reaction tank and sealed. After pre-crystallization at a hydrothermal temperature of 95°C for 5 hours, the mixture was crystallized at a hydrothermal temperature of 150°C for 96 hours to obtain a crystallized product. The crystallized product was cooled, filtered, washed, and dried to obtain a final solid product.

[0238] In the above, the molar ratio of the isobutylene triethoxysilane, pseudoboehmite, sodium hydroxide, hexamethylammonium hydroxide HM(OH)2 aqueous solution and deionized water is 80:1:160:20:2000; the above isobutylene triethoxysilane contains a structural unit; the isobutylene triethoxysilane containing the structural unit is prepared in the same way as in Example 1.

[0239] The final solid product obtained is EU-1 molecular sieve KE29, and XRD test shows that it has EUO structure; the silicon-aluminum molar ratio in KE29 is 67.8, and the specific surface area S BET 438m 2 / g, micropore specific surface area S micro 370m 2 / g, the relative crystallinity of the crystals is 89%, and the average particle size of the grains is 220nm.

[0240] Embodiment 30

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

[0242] Pseudo-boehmite (alumina mass content 70.3%) was dissolved in deionized water to obtain 21.9wt% solution A. Isobutylene triethoxysilane was dissolved in deionized water to obtain 31.7wt% solution B. The 31.7wt% solution B was added dropwise to the 21.9wt% solution A within 5 hours under stirring at a rate of 330rpm and reacted to form a gel at a temperature of 22°C. Then, a 25wt% aqueous solution of hexamethylammonium hydroxide HM(OH)2 was added, stirred for 1 hour, and then the pH value was adjusted to 10.5 with a 5wt% aqueous ammonia solution, and then aged for 1.5 hours at a temperature of 22°C to obtain an initial gel. The initial gel was then transferred into a stainless steel reaction tank and sealed. After pre-crystallization at a hydrothermal temperature of 95°C for 5 hours, it was crystallized at a hydrothermal temperature of 155°C for 70 hours to obtain a crystallized product. The crystallized product was cooled, filtered, washed, and dried to obtain a final solid product.

[0243] In the above, the molar ratio of the isobutylene triethoxysilane, pseudo-boehmite, ammonia water, hexamethylammonium hydroxide HM(OH)2 aqueous solution and deionized water is 85:1:10:8:600; the above isobutylene triethoxysilane contains a structural unit; the isobutylene triethoxysilane containing the structural unit is prepared in the same way as in Example 1.

[0244] The final solid product obtained is EU-1 molecular sieve KE30, and XRD test shows that it has EUO structure; the silicon-aluminum molar ratio in KE30 is 69.1, and the specific surface area S BET 477m 2 / g, micropore specific surface area S micro 407m 2 / g, the relative crystallinity of the crystals is 93%, and the average particle size of the grains is 120nm.

[0245] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to 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 words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A EU-1 molecular sieve, characterized in that The silicon-aluminum molar ratio of the EU-1 molecular sieve is 5 to 500, and the specific surface area S of the EU-1 molecular sieve is BET 400m 2 / g~700m 2 / g, micropore 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 crystallites 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 is BET 409m 2 / g~525m 2 / g, and / or micropore 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 crystallites in the EU-1 molecular sieve is 10nm to 200nm.

3. A method for synthesizing the EU-1 molecular sieve according to claim 1 or 2, characterized in that: The method comprises the steps of mixing a silicon source, an aluminum source, an alkali source, a template and a solvent I, aging and crystallizing to obtain a EU-1 molecular sieve; the silicon source is selected from a silicon source containing a structural unit; preferably, in the ultraviolet Raman spectrum of the silicon source containing the structural unit, at a vibration frequency of 240cm -1 There are characteristic peaks nearby, with a vibration frequency no greater than 600cm -1 In the characteristic area, there is at least one non-240cm -1 Characteristic peaks near 240cm -1 The sum of the peak areas of the nearby characteristic peaks is no more than 600 cm -1 The characteristic peak area of ​​the characteristic region accounts for 20% to 98% of the total area.

4. 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 pseudo-boehmite.

5. The synthesis method according to claim 3 or 4, characterized in that: The alkaline source is selected from at least one of ammonia water, sodium hydroxide, potassium hydroxide, rubidium hydroxide and tetraethylammonium hydroxide.

6. The synthesis method according to any one of claims 3 to 5, characterized in that The template is selected from at least one of hexamethonium bromide, an aqueous solution or methanol solution of hexamethonium hydroxide, and a template precursor; preferably, the template precursor is prepared by dissolving a dihalogenated alkane and a monoamine in an organic solvent; preferably, the dihalogenated alkane is 1,6-dibromohexane or 1-chloro-6-bromohexane; preferably, the monoamine is trimethylamine; preferably, the organic solvent is acetone; preferably, the molar ratio of the dihalogenated alkane, the monoamine and the organic solvent I is: (1-50): (3-100): (5-50); further preferably, the mass concentration of the aqueous solution or methanol solution of hexamethonium hydroxide is 1%-40%, preferably 25%.

7. The synthesis method according to any one of claims 3 to 6, characterized in that The solvent I is selected from at least one of water, methanol, ethanol, isopropanol, imidazole-type ionic liquids, and [bmim]PF6 anionic ionic liquids.

8. The synthesis method according to any one of claims 3 to 7, characterized in that The silicon source, aluminum source, alkali source, template and solvent I are mixed to obtain an initial gel mixture; preferably, the molar ratio of the silicon source, aluminum source, alkali source, template and solvent I is (10-300):1:(0-300):(1-20):(20-2000), preferably (30-300):1:(0-100):(1-20):(20-2000).

9. The synthesis method according to any one of claims 3 to 8, characterized in that The aging is carried out at a temperature of 20° C. to 25° C., and the aging time is 0 h to 4 h, preferably 0.5 h to 4 h.

10. The synthesis method according to any one of claims 3 to 9, characterized in that: The crystallization adopts a segmented crystallization process, including pre-crystallization and crystallization; preferably, the pre-crystallization temperature is 30-120° C., and the pre-crystallization time is 0.5h-12h; further preferably, the crystallization temperature is 120-200° C., and the crystallization time is 12h-500h; And / or, the crystallization further includes cooling, washing and drying steps.

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