Recry-Beta molecular sieve and catalyst, preparation method thereof and application of Recry-Beta molecular sieve and catalyst in hydrocarbon conversion reaction

Abstract

The invention relates to the field of catalysts, and discloses a Recry-Beta molecular sieve, a catalyst, a preparation method of the Recry-Beta molecular sieve and the catalyst and application of the Recry-Beta molecular sieve and the catalyst in a hydrocarbon conversion reaction, and the preparation method of the molecular sieve comprises the following steps: carrying out acid pickling dealumination treatment on an H-Beta molecular sieve to obtain a Si-Beta molecular sieve; the method comprises the following steps: mixing a Si-Beta molecular sieve, a template agent and water, and crystallizing to obtain a Recry-Beta molecular sieve; the particle size of the H-Beta molecular sieve is less than 90 nm, and the molar weight ratio of the template agent to the Si-Beta molecular sieve based on SiO2 is 0.08-0.25. The molecular sieve prepared by the invention can promote the interaction of Zr and molecular sieve framework elements, is suitable for the reaction of preparing 1, 3-butadiene from ethanol-acetaldehyde, shows excellent catalytic performance, and obviously improves the conversion rate of raw materials, the selectivity of 1, 3-butadiene and the stable operation time.

Description

Technical Field

[0001] The present invention relates to the field of catalysts, and in particular to a Recry-Beta molecular sieve and a preparation method thereof, a catalyst and a preparation method thereof, and application of the Recry-Beta molecular sieve or the catalyst in hydrocarbon conversion reactions. Background Art

[0002] Butadiene (1,3-Butadiene, BD) is an important petrochemical raw material and an intermediate monomer of synthetic rubber. It plays an important role in industrial production, especially in rubber production and the automobile industry. With the development of naphtha cracking technology to produce ethylene, about 97% of the world's butadiene is produced by extracting the by-product 1,3-butadiene from the carbon four fraction. However, with the increasing scarcity of oil resources and the continuous rise in oil prices, the process of producing butadiene using the oil route is bound to be affected. Therefore, it is urgently needed to develop a non-petroleum route for butadiene production. In recent years, with the continuous maturity of bioethanol production technology and the gradual increase in production scale, the ethanol method for preparing butadiene will be a new method to replace the petroleum route. There are two production processes for preparing butadiene (ETB) from ethanol: the one-step process (Makshina EV, Dusselier M, Janssens W, et al. Chemical Society Reviews, 2014, 43(22): 7917-7953.), which is the Lebedev process developed in the 1920s, using ethanol as a raw material to produce butadiene. This process has a low butadiene selectivity and a high acetaldehyde selectivity. The selectivity of butadiene is increased by recycling acetaldehyde to 30-40%; the two-step process (Alessandro M, Oberto C. Process for the manufacture of diolefins from alcohols and aldehydes. US2297424A.1942.; Dunn JT, Toussaint W J. Process for making diolefins. US2421361A[P].1947.), namely the Ostromyslensky process developed in 1942, partially dehydrogenates ethanol in the first reactor to produce acetaldehyde, and converts the ethanol-acetaldehyde mixture into butadiene in the second reactor, with a selectivity of up to 60%. Among them, the two-step process has more significant advantages.

[0003] Both the one-step and two-step processes include the following five reaction steps: ① ethanol dehydrogenation to generate acetaldehyde; ② acetaldehyde undergoes aldol condensation reaction to generate butane aldol; ③ butane aldol dehydration to generate crotonaldehyde; ④ crotonaldehyde and ethanol undergo MPV reaction to generate crotyl alcohol and acetaldehyde; ⑤ crotyl alcohol dehydration to generate butadiene. Among them, the catalyst for the dehydrogenation of ethanol to generate acetaldehyde is mostly Ag and Cu, which can meet the needs of industrial production. Regarding the requirements for the second step reaction in the two-step process, existing research results have shown that elements such as Ta, Zr, Zn and Mg can enter the molecular sieve framework or pores, showing L acid centers, which are active centers in aldol condensation and MPV reduction reactions (T.-W.Kim, J.-W.Kim, C.-U.Kim, Chem. Eng. J. 2015, 278, 217-223); Si-OH on the surface of SiO2, MWW and Beta molecular sieves behaves as weak B acid, which is the active center for dehydration reactions (M.Gao, H.Jiang, M.Zhang, Catal. Surveys Asia 2020, 1-8; VL Shushkevich, IIIvanova, E.Taarning, Green Chem. 17 (4) (2015) 2552–2559.; PI Kyriienko, OV Larina, SOSoloviev, SM Orlyk, S. Dzwigaj. Catal. Commun. 77 (2016) 123–126.; Minhua Zhang, etc. Microporous and Mesoporous Materials 326 (2021) 111359). Among them, the Zr-Beta catalyst containing metal zirconium with pure silicon beta molecular sieve as the carrier has a high butadiene selectivity, with a raw material conversion rate of 43.2% and a butadiene selectivity of 73.9%. However, the activity stability of the catalyst is poor, it is easy to deposit carbon, and it only runs for a few hours. This is because the structure of the Beta molecular sieve is destroyed in the two processes of dealumination and metal loading, and the crystallinity is greatly reduced. Therefore, how to maintain good crystallinity of the molecular sieve is a key factor in improving catalyst performance. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a Beta molecular sieve (denoted as Recry-Beta molecular sieve) with high crystallinity and a catalyst prepared based on the Recry-Beta molecular sieve, which catalyst exhibits excellent catalytic performance in the reaction of ethanol-acetaldehyde to prepare 1,3-butadiene.

[0005] In order to achieve the above object, the first aspect of the present invention provides a method for preparing Recry-Beta molecular sieve, the method comprising:

[0006] (1) acid washing and dealuminization of H-Beta molecular sieve to obtain Si-Beta molecular sieve;

[0007] (2) mixing Si-Beta molecular sieve, template and water, and then performing crystallization treatment to obtain the Recry-Beta molecular sieve;

[0008] Wherein, the particle size of the H-Beta molecular sieve is less than 90 nm;

[0009] The molar ratio of the template to the Si-Beta molecular sieve calculated as SiO2 is 0.08-0.25.

[0010] The second aspect of the present invention provides the Recry-Beta molecular sieve prepared by the method as described above.

[0011] The third aspect of the present invention provides a method for preparing a catalyst, which comprises: loading Zr onto the Recry-Beta molecular sieve as described above, and then drying and calcining the catalyst to obtain the catalyst.

[0012] A fourth aspect of the present invention provides a catalyst, which comprises the Recry-Beta molecular sieve as described above and a zirconium-containing species supported on the Recry-Beta molecular sieve.

[0013] A fifth aspect of the present invention provides use of the Recry-Beta molecular sieve or the catalyst described above in a hydrocarbon conversion reaction, preferably in a reaction of preparing 1,3-butadiene from ethanol-acetaldehyde.

[0014] The present invention prepares a small-size Si-beta molecular sieve by acid-washing and dealuminizing a small-size H-beta molecular sieve, and then crystallizes the small-size Si-beta molecular sieve to obtain the Beta molecular sieve (denoted as Recry-Beta molecular sieve) of the present invention. The Recry-Beta molecular sieve has a smaller particle size, more silanol groups and higher crystallinity, can promote the interaction between metal and molecular sieve framework elements, improves metal dispersion, improves the activity and selectivity of the catalyst, and prolongs the operation time of the catalyst.

[0015] The Zr-containing catalyst prepared by the Recry-Beta molecular sieve prepared by the method described in the present invention can be used in the reaction of preparing 1,3-butadiene from ethanol-acetaldehyde, and the catalyst exhibits excellent catalytic performance, significantly improving the conversion rate of the raw material, the selectivity of 1,3-butadiene and the stable operation time. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1is the XRD diagram of the molecular sieve prepared in Preparation Example 1-5 of the present invention;

[0017] Figure 2 is a TEM image of the H-Beta molecular sieve prepared in Preparation Example 1 of the present invention;

[0018] Figure 3 is a TEM image of the Si-Beta molecular sieve prepared in Preparation Example 2 of the present invention;

[0019] Figure 4 is a TEM image of the Recry-Beta molecular sieve prepared in Preparation Example 3 of the present invention;

[0020] Figure 5 is a TEM image of the Recry-Beta molecular sieve prepared in Preparation Example 4 of the present invention;

[0021] Figure 6 is a TEM image of the Recry-Beta molecular sieve prepared in Preparation Example 5 of the present invention;

[0022] Figure 7 is an isotherm graph of the molecular sieve prepared in Preparation Example 1-3 of the present invention;

[0023] Figure 8 XRD diagrams of the catalysts prepared in Example 1 and Comparative Example 1 of the present invention;

[0024] Fig. 9 The molecular sieve or catalyst of Preparation Examples 1-3, Example 1 and Comparative Example 1 of the present invention 29 Si MAS NMR images;

[0025] Fig.10 UV-Vis images of the catalysts prepared in Example 1 of the present invention and Comparative Example 1;

[0026] Fig.11 The XPS graphs of the catalysts prepared in Example 1 and Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0027] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0028] The technical terms in the present invention shall be understood according to their definitions if they are defined, and shall be understood according to their general meanings in the art if they are not defined.

[0029] The first aspect of the present invention provides a method for preparing a Recry-Beta molecular sieve, the method comprising:

[0030] (1) acid washing and dealuminization of H-Beta molecular sieve to obtain Si-Beta molecular sieve;

[0031] (2) mixing Si-Beta molecular sieve, template and water, and then performing crystallization and calcination treatment to obtain the Recry-Beta molecular sieve;

[0032] Wherein, the particle size of the H-Beta molecular sieve is less than 90 nm (for example, it can be 20, 30, 40, 50, 60, 70, 80, 90 nm or less and any range between any two values);

[0033] Among them, the molar ratio of the template and the Si-Beta molecular sieve calculated as SiO2 is 0.08-0.25 (for example, it can be 0.08, 0.1, 0.12, 0.14, 0.15, 0.16, 0.17, 0.18, 0.2, 0.25 and any range between any two values, preferably 0.13-0.18).

[0034] Preferably, the particle size of the H-Beta molecular sieve is 20-50 nm.

[0035] In the present invention, the particle sizes of the molecular sieve and the catalyst can be measured by transmission electron microscopy.

[0036] The H-beta molecular sieve can be purchased commercially or prepared at home. The preparation method thereof can be found in patent CN1324762A, which is incorporated herein by reference in its entirety.

[0037] In a preferred embodiment of the present invention, a silicon source, an aluminum source and a template are mixed under alkaline conditions and then subjected to hydrothermal crystallization, drying, ammonium exchange and calcination to obtain an H-beta molecular sieve. There is no particular restriction on the order of ammonium exchange and calcination.

[0038] The alkaline condition can be provided by a common alkaline substance in the art, such as sodium hydroxide.

[0039] The silicon source may be a conventional silicon source in the art, such as silicon dioxide or silica gel.

[0040] Preferably, the aluminum source is selected from one or more of alkali metal (meta)aluminates (such as sodium metaaluminate), hydrated aluminum oxide, aluminum hydroxide, hydrated aluminum chloride, and pseudo-boehmite.

[0041] Preferably, the template has at least one of the structures shown in formula (1):

[0042]

[0043] Wherein, R1, R2, R3 and R4 are each independently selected from an alkyl group having 1 to 4 carbon atoms, preferably, R1, R2, R3 and R4 are each independently selected from one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl, more preferably methyl or ethyl;

[0044] X - Including hydroxide ions or halogen anions.

[0045] Preferably, the template is tetramethylammonium hydroxide and / or tetraethylammonium hydroxide.

[0046] It should be understood that the hydrothermal crystallization is performed under water-containing conditions.

[0047] Preferably, the amounts of the components are such that, in molar terms, SiO2 / Al2O3 is 10-50 (e.g., 10, 20, 30, 40, 50, and any range between any two values), H2O / SiO2 is 5-8 (e.g., 5, 6, 7, 8, and any range between any two values), template / SiO2 is 0.05-0.15 (e.g., 0.05, 0.08, 0.1, 0.12, 0.15, and any range between any two values), OH - / SiO2 is 0.1-0.15 (for example, it can be 0.1, 0.11, 0.12, 0.13, 0.14, 0.15 and any range between any two values).

[0048] Preferably, the hydrothermal crystallization is maintained at 120-200°C and autogenous pressure for 5-120 hours, more preferably at 80-138°C (preferably 110-130°C) and autogenous pressure for 5-72 hours (preferably 16-32 hours), and then at 140-200°C (preferably 140-160°C) and autogenous pressure for 5-72 hours (preferably 36-56 hours).

[0049] The drying and ammonium exchange methods are conventional methods in the art and will not be described in detail herein. The calcination conditions may be, for example, a temperature of 500-600° C. and a time of 3-5 hours.

[0050] Preferably, the conditions for acid washing and aluminum removal are such that the mass content of silicon dioxide in the obtained Si-Beta molecular sieve is above 99.5%, for example, it can be 99.5, 99.6, 99.7, 99.8, 99.9wt% or above and any range between any two values, thereby reducing the impurity content of the catalyst.

[0051] Preferably, the conditions for pickling include: a temperature of 60-90° C., an acid selected from one or more of nitric acid, hydrochloric acid and sulfuric acid, and a concentration of the pickling solution of generally 1-15 mol / L. The number and time of acid exchange are determined according to the content of silicon dioxide (or aluminum oxide) in the molecular sieve during actual operation.

[0052] The material obtained after acid washing can be subsequently treated to obtain the Si-Beta molecular sieve. The subsequent treatment operations may include filtering, washing and drying, etc., which can all refer to conventional operations in the art.

[0053] Preferably, the crystallinity of the Si-Beta molecular sieve is 60-90%, such as 60, 65, 70, 75, 80, 85, 90% and any range between any two values, more preferably 70-85%.

[0054] The crystallinity is measured by XRD, which is calculated as the sum of the characteristic peak areas of 2θ=7-9° and 22-23°, and the standard sample is the H-beta molecular sieve prepared in Preparation Example 1 of the present invention.

[0055] Preferably, the BET specific surface area S of the Si-Beta molecular sieve is BET 450-680m 2 / g, for example, 450, 480, 500, 550, 600, 650, 680m 2 / g and any range between any two values, more preferably 480-650m 2 / g.

[0056] Preferably, the total pore volume V of the Si-Beta molecular sieve is 总 0.25-0.85cm 3 / g, for example, 0.25, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.85 cm 3 / g and any range between any two values, more preferably 0.45-0.7cm 3 / g.

[0057] Preferably, the stacking pore volume V of the Si-Beta molecular sieve is meso 0.2-0.55cm 3 / g, for example, 0.23, 0.25, 0.3, 0.4, 0.5, 0.55 cm 3 / g and any range between any two values, more preferably 0.26-0.48cm 3 / g.

[0058] Among them, specific surface area, pore volume and pore capacity can be measured by nitrogen adsorption instrument.

[0059] Preferably, the molar ratio of the template to the Si-Beta molecular sieve calculated as SiO2 is 0.1-0.2 (for example, it can be 0.1, 0.12, 0.14, 0.16, 0.18, 0.2, and any range between any two values). The template is referred to as the template for preparing the H-beta molecular sieve, which will not be described in detail here.

[0060] Preferably, the molar ratio of water to Si-Beta molecular sieve calculated as SiO2 is 3-10, such as 3, 4, 6, 8, 10 and any range between any two values, more preferably 5-8.

[0061] Preferably, the crystallization conditions include: a crystallization temperature of 100-300° C., more preferably 110-150° C.; a crystallization time of 12 h-120 h, more preferably 24 h-72 h. It should be understood that the pressure is autogenous pressure.

[0062] Preferably, the crystallization is carried out in two steps, more preferably, crystallization is carried out at 110-130° C. for 18-36 h, and then crystallization is carried out at 130-150° C. for 18-36 h.

[0063] Preferably, the calcination conditions include: a calcination temperature of 400-650° C., more preferably 500-600° C.; and a calcination time of 2-8 h, preferably 3 h-5 h.

[0064] The second aspect of the present invention provides the Recry-Beta molecular sieve prepared by the method as described above.

[0065] Preferably, the silicon-aluminum ratio of the Recry-Beta molecular sieve is above 800, for example, it can be 800, 1000, 1500, 2000, 2500 or above and any range between any two values, more preferably 1200-2500.

[0066] Preferably, the crystallinity of the Recry-Beta molecular sieve is 50-100%, such as 50, 60, 65, 70, 75, 80, 85, 90, 100% and any range between any two values, more preferably 55-80%.

[0067] Preferably, the BET specific surface area S of the Recry-Beta molecular sieve is BET 450-680m 2 / g, for example, 450, 480, 500, 550, 600, 650, 680m 2 / g and any range between any two values, more preferably 500-660m 2 / g.

[0068] Preferably, the total pore volume V of the Recry-Beta molecular sieve is 总 0.25-0.85cm 3 / g, for example, 0.25, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.85 cm 3 / g and any range between any two values, more preferably 0.45-0.7cm 3 / g.

[0069] Preferably, the stacking pore volume V of the Recry-Beta molecular sieve is meso 0.2-0.55cm 3 / g, for example, 0.23, 0.25, 0.3, 0.4, 0.5, 0.55 cm 3 / g and any range between any two values, more preferably 0.26-0.48cm 3 / g.

[0070] The third aspect of the present invention provides a method for preparing a catalyst, which comprises: loading Zr onto the Recry-Beta molecular sieve as described above, and then drying and calcining the catalyst to obtain the catalyst.

[0071] The catalyst of the present invention can be prepared by referring to the conventional methods in the art. For example, it can be prepared by conventional impregnation method (i.e., equal volume impregnation method), or it can be prepared by ion exchange method. The impregnation method is to contact the precursor solution of Zr with the Recry-Beta molecular sieve, wherein the precursor of Zr can be a water-soluble compound and an alcohol-soluble compound of Zr, such as nitrate (such as ZrO(NO3)2·2H2O), chloride and acetate. One or more of the impregnation methods can be conventional methods in the art, which will not be repeated here.

[0072] Preferably, the loading method includes: impregnating the Recry-Beta molecular sieve with a Zr precursor solution.

[0073] Preferably, the immersion conditions include: pH 3-12, such as 3, 5, 7, 9, 11, 12 and any range between any two values, more preferably 7-11; temperature 20-60°C, such as 20, 30, 40, 50, 60°C and any range between any two values.

[0074] The pH of the zirconium precursor solution may be adjusted to be in the range of 7-11 using an alkaline substance. Preferably, the alkaline substance is ammonia and / or ammonium salt (such as ammonium chloride, ammonium sulfate, ammonium nitrate, etc.).

[0075] The immersion time can be appropriately selected according to the dispersion degree of the precursor. Preferably, the immersion time is 1-5 hours.

[0076] In addition, the amount of solvent in the solution of the Zr precursor should satisfy the requirement that the Zr precursor can be fully dissolved in the solvent on the one hand, and the molecular sieve can be fully dispersed on the other hand. Preferably, compared with 1g of Recry-Beta molecular sieve, the amount of solvent in the solution of the Zr precursor is 10-400ml, preferably 20-50ml. The solvent can be at least one of water, ethanol and propanol.

[0077] Preferably, the amount of each component is such that, based on the total weight of the catalyst, the content of Recry-Beta molecular sieve is 95-99.9wt%, such as 95, 96, 97, 98, 99, 99.5, 99.9wt% or more and any range between any two values, more preferably 97-99.5wt%, and the content of zirconium-containing species calculated as Zr oxide is 0.1-5wt%, such as 0.1, 0.5, 1, 2, 3, 4, 5wt% or more and any range between any two values, more preferably 0.5-3wt%.

[0078] It should be understood that the zirconium-containing species may be zirconium oxide or other forms of zirconium.

[0079] There is no particular restriction on the drying conditions, for example, the drying can be carried out at 60-120° C. There is no particular restriction on the drying time, as long as the drying is carried out until the weight is constant.

[0080] Preferably, the calcination conditions include: a temperature of 400-600° C. and a time of 1-6 hours.

[0081] A fourth aspect of the present invention provides a catalyst, which comprises the Recry-Beta molecular sieve as described above and an oxide of Zr supported on the Recry-Beta molecular sieve.

[0082] Preferably, based on the total weight of the catalyst, the content of Recry-Beta molecular sieve is 95-99.9wt%, such as 95, 96, 97, 98, 99, 99.5, 99.9wt% or more and any range between any two values, more preferably 97-99.5wt%, and the content of zirconium-containing species calculated as Zr oxide is 0.1-5wt%, such as 0.1, 0.5, 1, 2, 3, 4, 5wt% or more and any range between any two values, more preferably 0.5-3wt%.

[0083] In a preferred embodiment of the present invention, the present invention provides a catalyst, wherein the crystallinity of the catalyst is 30-85%, such as 30, 35, 40, 45, 50, 60, 65, 70, 75, 80, 85% and any range between any two values, preferably 40-75%; and / or the silicon-aluminum ratio of the catalyst is above 800, such as 800, 1000, 1500, 2000, 2500 or more and any range between any two values, preferably 1200-2500; and / or the BET specific surface area S of the catalyst is BET 450-680m 2 / g, for example, 450, 480, 500, 550, 600, 650, 680m 2 / g and any range between any two values, preferably 480-650m 2 / g; and / or the total pore volume V of the catalyst 总 0.35-0.7cm 3 / g, for example, 0.35, 0.4, 0.5, 0.6, 0.7 cm 3 / g and any range between any two values, preferably 0.44-0.65cm 3 / g; and / or the accumulated pore volume V of the catalyst meso 0.1-0.7cm 3 / g, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 cm 3 / g and any range between any two values, preferably 0.2-0.55cm 3 / g.

[0084] A fifth aspect of the present invention provides use of the Recry-Beta molecular sieve or the catalyst described above in a hydrocarbon conversion reaction, preferably in a reaction of preparing 1,3-butadiene from ethanol-acetaldehyde.

[0085] The conditions for preparing 1,3-butadiene can be carried out with reference to the prior art, and are based on the ability to prepare 1,3-butadiene from ethanol-acetaldehyde.

[0086] According to the present invention, the conditions for the contact reaction of ethanol and acetaldehyde generally include reaction temperature and reaction pressure, wherein the reaction temperature can be maintained at 250-450°C, preferably 250-400°C; the reaction pressure can be maintained at 0.1-4MPa, preferably 0.1-1.5MPa. As long as the catalyst described in the present invention is used, the purpose of the present invention can be achieved. From the perspective of further improving the catalytic activity of the catalyst, the amount of the catalyst is set based on the total amount of ethanol and acetaldehyde so that the gas hourly space velocity of the reactants is 0.1-9 hours. -1 (h -1 ), preferably 0.1-6 hours -1 (h -1 ). The molar ratio of ethanol to acetaldehyde in the feed may be 1-12, preferably 1.5-5.

[0087] In the method of the present invention, the reaction of preparing 1,3-butadiene from ethanol can be carried out in various reactors conventionally used in the art, for example, including but not limited to at least one of a fixed bubbling bed reactor, a fixed trickle bed reactor and a slurry bed reactor.

[0088] The present invention will be described in detail below through examples.

[0089] (1) In the following examples, the particle size of the molecular sieves was analyzed by TEM.

[0090] (2) In the following examples, the crystallinity of the molecular sieve and the catalyst was determined by XRD analysis, with the sum of the characteristic peak areas of 2θ=7-9° / 22-23° of the H-Beta molecular sieve prepared in Preparation Example 1 as the reference.

[0091] (3) In the following examples, the specific surface area and pore volume of the molecular sieve and catalyst were measured according to the following analytical methods:

[0092] Equipment: Micromeritic ASAP2010 static nitrogen adsorption instrument.

[0093] Measurement conditions: The sample was placed in a sample handling system and vacuumed to 1.33×10 -2 Pa, keep the temperature and pressure for 15 hours, and purify the sample. At liquid nitrogen temperature -196 ° C, measure the adsorption and desorption of nitrogen by the purified sample under different pressure ratios P / P0 to obtain the adsorption-desorption isotherm curve. Then use the two-parameter BET formula to calculate the total specific surface area, and the total pore volume is calculated based on the adsorption at P / P0 = 0.98.

[0094] (4) In the following examples, the silicon-aluminum ratio analysis was performed using a 3013 X-ray fluorescence spectrometer produced by Rigaku Corporation. Test conditions: tungsten target, excitation voltage 40 kV, excitation current 50 mA. Experimental process: The catalyst sample was pressed into a tablet and mounted on the X-ray fluorescence spectrometer. Under the irradiation of X-rays, the sample emitted fluorescence. The fluorescence wavelength λ and the atomic number Z of the element have the following relationship: λ=K(Z-S) -2 , K is a constant. As long as the wavelength λ of the fluorescence is measured, the element can be determined. The intensity of the characteristic spectral line of each element is measured with a scintillation counter and a proportional counter to perform quantitative or semi-quantitative analysis of the element.

[0095] In the following examples, all reagents and raw materials can be purchased commercially or prepared according to existing methods.

[0096] Preparation Example 1

[0097] This preparation example is used to illustrate the preparation method of H-beta molecular sieve.

[0098] 5.17g of sodium aluminate solution (specific gravity 1.24g / ml, mass fraction of NaOH 15.65%, mass fraction of Al2O3 8.19%) was added to a 45mL polytetrafluoroethylene container, 9.33g of template (tetraethylammonium hydroxide) aqueous solution (mass fraction 26.46%) was added, stirred for 30 minutes until uniform, and then 10g of solid silica gel (mass fraction of SiO2 99.30%) and 8.823g of deionized water were added, stirred for 5 minutes to fully mix, wherein the molar ratio of each component is: SiO2 / Al2O3=25, H2O / SiO2=6.5, template / SiO2=0.1, OH - / SiO2=0.12.

[0099] The above mixture was placed in a 45mL polytetrafluoroethylene-lined steel autoclave, covered and sealed, and the autoclave was placed in a rotating convection oven with a speed set to 20rpm. The reaction was carried out at 120℃ for 24h and at 145℃ for 48h. The autoclave was taken out and quickly cooled to room temperature. The mixture was separated on a high-speed centrifuge at 5000rpm, the solid was collected, fully washed with deionized water, and dried at 100℃ for 24h to obtain the Beta structure molecular sieve raw powder. After the raw powder was treated with ammonium exchange and calcined at 550℃ for 4h, the hydrogen type sample was obtained and recorded as H-Beta molecular sieve.

[0100] The XRD pattern of this product is as follows Figure 1 As shown, its crystallinity is defined as 100%; the transmission electron microscope image is shown Figure 2 As shown, the molecular sieve particle size is in the range of 20-50nm; the isotherm curve is as shown in Figure 7 As shown, a hysteresis loop appears; 29Si MAS NMR images Fig. 9 As shown, characteristic peaks such as Si(3Si,1OH) (chemical shift -116), Si(4Si) (chemical shift -111) and Si(3Si,1Al) (chemical shift -101) appeared.

[0101] The results of the particle size, crystallinity and silicon-to-aluminum ratio of the product are shown in Table 1, and the results of the surface area and pore volume are shown in Table 2.

[0102] Preparation Example 2

[0103] This preparation example is used to illustrate the preparation method of Si-beta molecular sieve.

[0104] The H-Beta molecular sieve prepared in Preparation Example 1 was mixed with a 13 mol / L HNO3 solution at 80°C, acid-washed for 12 hours, filtered and washed until pH = 4, mixed with distilled water at 80°C, and washed with water for 4 hours. The dealuminated Beta molecular sieve was recovered by filtration, washed with distilled water until neutral, and dried at 80°C for 24 hours to obtain Si-Beta molecular sieve.

[0105] The XRD pattern of this product is as follows Figure 1 As shown in the transmission electron microscopy image Figure 3 As shown, the isotherm curve is Figure 7 As shown, 29 SiMAS NMR images Fig. 9 shown.

[0106] The results of the particle size, crystallinity and silicon-to-aluminum ratio of the product are shown in Table 1, and the results of the surface area and pore volume are shown in Table 2.

[0107] Preparation Example 3

[0108] This preparation example is used to illustrate the preparation method of the beta molecular sieve (denoted as Recry-Beta molecular sieve) described in the present invention.

[0109] In a polytetrafluoroethylene container, the Si-Beta molecular sieve prepared in Preparation Example 2 was used as a raw material, and a template and water were added to perform crystallization. The crystallization method included reacting at 120°C for 24 hours under closed conditions, and then reacting at 145°C for 24 hours to obtain a molecular sieve raw powder (crystallinity of 95.4%). After the raw powder was calcined at 550°C for 4 hours to remove the template, the sample obtained was recorded as Recry-Beta molecular sieve-1. The molar ratio of each component is: H2O / Si-Beta=6.5, template / Si-Beta=0.16, wherein the molar amount of Si-Beta is calculated based on silicon dioxide, and the template is tetramethylammonium hydroxide.

[0110] The XRD pattern of the obtained product is as follows Figure 1 As shown in the transmission electron microscopy image Figure 4 As shown, the isotherm curve is Figure 7 As shown, 29 Si MAS NMR images Fig. 9 shown.

[0111] The results of the particle size, crystallinity and silicon-to-aluminum ratio of the product are shown in Table 1, and the results of the surface area and pore volume are shown in Table 2.

[0112] Preparation Example 4

[0113] This preparation example is used to illustrate the preparation method of the beta molecular sieve (denoted as Recry-Beta molecular sieve) described in the present invention.

[0114] Recry-Beta molecular sieve was prepared according to the method described in Preparation Example 3, except that the molar ratio of the template to the Si-Beta molecular sieve was 0.13. The obtained sample was recorded as Recry-Beta molecular sieve-2.

[0115] The XRD pattern of the obtained product is as follows Figure 1 As shown in the transmission electron microscopy image Figure 5 As shown, the crystallinity of the original powder is 86.0%.

[0116] The results of the particle size, crystallinity and silicon-to-aluminum ratio of the product are shown in Table 1, and the results of the surface area and pore volume are shown in Table 2.

[0117] Preparation Example 5

[0118] This preparation example is used to illustrate the preparation method of the beta molecular sieve (denoted as Recry-Beta molecular sieve) described in the present invention.

[0119] Recry-Beta molecular sieve was prepared according to the method described in Preparation Example 3, except that the molar ratio of the template to the Si-Beta molecular sieve was 0.10. The obtained sample was recorded as Recry-Beta molecular sieve-3.

[0120] The XRD pattern of the obtained product is as follows Figure 1 As shown in the transmission electron microscopy image Figure 6 As shown in Figure 2, the crystallinity of the original powder is 71.5%.

[0121] The results of the particle size, crystallinity and silicon-to-aluminum ratio of the product are shown in Table 1, and the results of the surface area and pore volume are shown in Table 2.

[0122] Table 1

[0123] name Mold-to-silicon ratio / mol Particle size / nm Crystallinity / % Silicon to aluminum ratio H-Beta / 20-50 100 20 Si-Beta / 20-50 73.9 2440 Recry-Beta-1 0.16 20-30 75.4 1240 Recry-Beta-2 0.13 20-30 72.9 1374 Recry-Beta-3 0.1 20-50 58.3 1470

[0124] It can be seen from the results in Table 1 that as the silicon-to-silicon ratio increases, the crystallinity of the Recry-Beta molecular sieve increases, and the particle size and silicon-to-aluminum ratio further decrease.

[0125] Table 2

[0126]

[0127] From the results in Table 2, it can be seen that compared with Si-Beta molecular sieve, the BET specific surface area S of Recry-Beta molecular sieve is BET and micropore volume V micro All of them have increased, indicating that the molecular sieve structure is more complete; except for Recry-Beta-3, the surface area S external and the stacking pore volume V meso increases, indicating that the particle size of the molecular sieve is further reduced.

[0128] Preparation Example 6

[0129] This preparation example is used to illustrate the preparation method of the beta molecular sieve (denoted as Recry-Beta molecular sieve) described in the present invention.

[0130] Recry-Beta molecular sieve was prepared according to the method described in Preparation Example 3, except that the molar ratio of the template to the Si-Beta molecular sieve was 0.18. The obtained sample was recorded as Recry-Beta molecular sieve-4.

[0131] Comparative Preparation Example 1

[0132] This comparative preparation example is used to illustrate the preparation method of comparative beta molecular sieve.

[0133] The molecular sieve D1 was prepared according to the method described in Preparation Examples 2 and 3, except that the H-beta molecular sieve was purchased from Qilu Catalyst Company and had a particle size greater than 100 nm.

[0134] Comparative Preparation Example 2

[0135] This comparative preparation example is used to illustrate the preparation method of comparative beta molecular sieve.

[0136] Si-beta molecular sieve was prepared according to the literature method (Miguel A. Camblor, Avelino Corma and Susana Valencia, Spontaneous nucleation and growth of pure silica zeolite-Betafree of connectivity defects, Chem. Cornmun., 1996, 2365-2366), and the preparation method of the Si-beta molecular sieve was as follows: 43.62 grams of tetraethylammonium hydroxide (35% aqueous solution, Aldrich) and 6.21 grams of deionized water were mixed in a plastic container. Tetraethyl orthosilicate (Merck) was added, and the mixture was stirred at 25°C for 6.5 hours. 4.32g HF (48% aqueous solution) was added to form a white solid. The above mixture was transferred to a stainless steel pressure vessel lined with polytetrafluoroethylene and crystallized at 150°C for 39 hours. The raw material composition was 0.54Et4OH:0.54HF:SiO2:7.25H2O. After the crystallization, the molecular sieve was filtered and washed to obtain a molecular sieve with a crystallinity of 110% and a particle size of 0.5-5 μm, thereby obtaining a molecular sieve D2.

[0137] Comparative Preparation Example 3

[0138] This comparative preparation example is used to illustrate the preparation method of comparative beta molecular sieve.

[0139] Recry-Beta molecular sieve was prepared according to the method described in Preparation Example 3, except that the molar ratio of the template to the Si-Beta molecular sieve was 0.05, to obtain molecular sieve D3.

[0140] Example 1

[0141] This example is used to illustrate the preparation method of the catalyst described in the present invention.

[0142] 4.0 g of the Recry-Beta molecular sieve-1 synthesized in Preparation Example 3 was taken and mixed with 120 mL of an aqueous solution containing 0.174 g of ZrO(NO3)2·2H2O (Acros Organic, 99.99%) at room temperature, and the pH was adjusted to 8 using aqueous ammonia. After continuous stirring for 6 hours, the suspension was placed in air at 100° C. and dried until all water was volatilized, and finally calcined in flowing air at 550° C. for 5 hours to obtain a catalyst 1. In the catalyst 1, the content of the Beta molecular sieve was 97.9%, and the content of the zirconium dioxide was 1.47 wt%.

[0143] Its XRD pattern is as follows Figure 8 As shown, the crystallinity of the catalyst is 60.9%. 29Si MAS NMR images Fig. 9 As shown, the UV-Vis image is Fig.10 As shown in the XPS diagram Fig.11 As shown, it can be seen from the figure that most of the metals enter the molecular sieve framework and form bonds with the framework elements.

[0144] It has been determined that the total specific surface area of ​​the catalyst is S BET =623m 2 / g, total pore volume V 总 =0.627cm 3 / g, stacking pore volume V meso =0.428cm 3 / g.

[0145] Embodiment 2-4

[0146] This example is used to illustrate the preparation method of the catalyst described in the present invention.

[0147] According to the method described in Example 1, Recry-Beta molecular sieves 2-4 prepared in Preparation Examples 4-6 were used to replace Recry-Beta molecular sieve-1 prepared in Preparation Example 3 to prepare catalysts 2-4.

[0148] Comparative Example 1

[0149] This comparative example is used to illustrate the preparation of a comparative catalyst.

[0150] 4.0 g of the Si-Beta molecular sieve synthesized in Preparation Example 2 was mixed with 120 mL of an aqueous solution containing 0.174 g of ZrO(NO3)2·2H2O (Acros Organic, 99.99%) at room temperature, and the pH was adjusted to 8 using aqueous ammonia. After continuous stirring for 6 hours, the suspension was placed in air at 100°C and dried until all the water was volatilized, and finally calcined in flowing air at 550°C for 5 hours to obtain a catalyst D1. In the catalyst D1, the content of the Beta molecular sieve was 98.1%, and the content of the zirconium dioxide was 0.89 wt%.

[0151] The XRD pattern of the sample is Figure 8 As shown, the crystallinity is 51.7%. 29 Si MAS NMR images Fig. 9 As shown, the UV-Vis image is Fig.10 As shown in the XPS diagram Fig.11 As shown, it can be seen from the figure that a small amount of metal enters the molecular sieve framework and forms bonds with the framework elements.

[0152] It was determined that the BET specific surface area of ​​the catalyst is S BET =529m 2 / g, the total pore volume is V 总 =0.540cm 3 / g, the stacking pore volume is V 堆积 =0.365cm 3 / g.

[0153] Comparative Example 2

[0154] This comparative example is used to illustrate the preparation of a comparative catalyst.

[0155] 2.0 g of Recry-Beta molecular sieve-1 synthesized in Preparation Example 3 was mixed with 3.3×10 -3 mol / L Zn(NO3)2 (Sinopharm Chemical Reagent Co., Ltd., 99.0%) and 100ml ethanol solution were mixed and stirred continuously for 3 hours. Then, the suspension (pH=6.8) was evaporated in a rotary distiller until the ethanol was completely evaporated. The obtained solid was washed three times in distilled water and dried in air at 80°C for 24 hours, and finally calcined in flowing air at 450°C for 3 hours to obtain catalyst D3. In the catalyst D3, the content of Beta structure molecular sieve is 98.1wt%, and the content of zinc oxide is 1.12wt%.

[0156] The crystallinity of the Zn-Beta-Recry structure molecular sieve is 62.9%, and the BET specific surface area is S BET =602m 2 / g, the total pore volume is V 总 =0.593cm 3 / g, the stacking pore volume is V 堆积 =0.408cm 3 / g.

[0157] Comparative Example 3

[0158] This comparative example is used to illustrate the preparation of a comparative catalyst.

[0159] 2.0 g of Recry-Beta molecular sieve-1 synthesized in Preparation Example 3 was mixed with 1.5×10 -3mol / L Ta(OC2H5)5 (Acros Organic, 99.99%) and 100mL isopropanol solution were mixed and stirred continuously for 3 hours. Then, the suspension (pH=6.8) was evaporated in a rotary distiller until the isopropanol was completely evaporated. The obtained solid was washed three times in distilled water and dried in air at 80°C for 24 hours, and finally calcined in flowing air at 450°C for 3 hours to obtain catalyst D4. In the catalyst D4, the content of Beta structure molecular sieve is 97.5wt%, and the content of tantalum oxide is 1.36wt%. The crystallinity of the Ta-Beta-Recry structure molecular sieve is 60.5%, and the BET specific surface area is S BET =594m 2 / g, the total pore volume is V 总 =0.586cm 3 / g, the stacking pore volume is V 堆积 =0.413cm 3 / g.

[0160] Comparative Examples 4-6

[0161] This comparative example is used to illustrate the preparation of a comparative catalyst.

[0162] The method described in Example 1 was followed, except that the molecular sieves prepared in Comparative Preparation Examples 1-3 were used instead of the molecular sieve prepared in Preparation Example 3 to prepare catalysts D4-D6.

[0163] Test Example 1

[0164] The fixed bed reactor is used to prepare 1,3-butadiene from ethanol. The reactor is a stainless steel tubular isothermal reaction tube with an inner diameter of 12 mm and a catalyst loading of 4 g. Ethanol and acetaldehyde (the concentration of acetaldehyde aqueous solution is 40 wt%) are introduced from the top of the reaction tube. The device is material balanced and the liquid recovery is more than 95%.

[0165] Evaluation conditions: based on a mixture of ethanol and acetaldehyde as reactants, gas hourly space velocity: 2h -1 ; Carrier gas flow rate: 450ml / min, reaction temperature: 350℃, reaction pressure: 0.44MPa, catalyst loading: 2.0g. Ethanol and acetaldehyde solution are used as raw materials, wherein ethanol: acetaldehyde = 2:1 (molar ratio).

[0166] For the convenience of expression, the following substances are abbreviated as: ethanol (EtOH), acetaldehyde (AA), unreacted ethanol (unreacted-EtOH), and unreacted acetaldehyde (unreacted-AA).

[0167] The ethanol conversion and 1,3-butadiene selectivity were calculated by the following formula:

[0168]

[0169]

[0170] Wherein, n is the mass percentage of each component in the product, and i is butadiene or other components in the product.

[0171] The catalysts prepared in the examples and comparative examples were respectively used in the reaction of ethanol-acetaldehyde to prepare 1,3-butadiene. The catalytic performance results are shown in Table 3 (sampling results when the reaction time is 2 h).

[0172] Table 3

[0173]

[0174]

[0175] From the results in Table 3, it can be seen that when the Zr catalyst prepared by the Beta molecular sieve of the present invention is used in the reaction of preparing 1,3-butadiene from ethanol, the conversion rate of ethanol-acetaldehyde is high, and the butadiene selectivity and yield are significantly better than those of the comparative example. This shows that the catalyst provided by the present invention has good catalytic performance.

[0176] from Fig.10 The results show that, compared with Comparative Example 1, most of the metals in the catalyst prepared in Example 1 enter the molecular sieve framework and form bonds with the framework elements, thereby improving the activity and selectivity of the catalyst and effectively extending the stable operation time (it can continuously operate for at least 60 hours when the ethanol-acetaldehyde conversion rate is above 40% and the butadiene selectivity is ≥65%). The catalyst prepared in Comparative Example 1 can only continuously operate for less than 20 hours when the butadiene yield is ≥25%, and the repeatability is poor; the operation time of the catalyst prepared in Comparative Example 4 is less than 25 hours, and the decay is fast.

[0177] According to the method described above, the catalyst 1 described in Example 1 of the present invention was used to prepare 1,3-butadiene under the condition of an alcohol-aldehyde ratio of 3:1. The results showed that the ethanol-acetaldehyde conversion rate was above 60%, and the butadiene selectivity was ≥40%, and the continuous operation was at least 130 hours.

[0178] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing Recry-Beta molecular sieve, characterized in that: The method includes: (1) acid washing and dealuminization of H-Beta molecular sieve to obtain Si-Beta molecular sieve; (2) mixing Si-Beta molecular sieve, template and water, and then performing crystallization treatment to obtain the Recry-Beta molecular sieve; Wherein, the particle size of the H-Beta molecular sieve is less than 90 nm; The molar ratio of the template to the Si-Beta molecular sieve calculated as SiO2 is 0.08-0.

25.

2. The method according to claim 1, wherein: The particle size of the H-Beta molecular sieve is 20-50 nm.

3. The method according to claim 1 or 2, wherein: The conditions for acid washing and aluminum removal are such that the content of silicon dioxide in the obtained Si-Beta molecular sieve is above 99.5wt%; Preferably, the crystallinity of the Si-Beta molecular sieve is 60-90%, more preferably 70-85%; Preferably, the BET specific surface area S of the Si-Beta molecular sieve is BET 450-680m 2 / g, more preferably 480-650m 2 / g; Preferably, the total pore volume V of the Si-Beta molecular sieve is 总 0.25-0.85cm 3 / g, more preferably 0.45-0.7cm 3 / g; Preferably, the stacking pore volume V of the Si-Beta molecular sieve is meso 0.2-0.55cm 3 / g, more preferably 0.26-0.48cm 3 / g.

4. The method according to any one of claims 1 to 3, wherein: The template has at least one of the structures shown in formula (1): Wherein, R1, R2, R3 and R4 are each independently selected from an alkyl group having 1 to 4 carbon atoms, preferably, R1, R2, R3 and R4 are each independently selected from one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl, more preferably methyl or ethyl; X - including hydroxide ions or halogen anions; Preferably, the template is tetramethylammonium hydroxide and / or tetraethylammonium hydroxide; Preferably, the molar ratio of the template to the Si-Beta molecular sieve calculated as SiO2 is 0.1-0.2; Preferably, the molar ratio of water to Si-Beta molecular sieve calculated as SiO2 is 3-10, more preferably 5-8.

5. The method according to any one of claims 1 to 4, wherein: The crystallization conditions include: a crystallization temperature of 100-300° C., preferably 110-150° C.; a crystallization time of 12h-120h, preferably 24h-72h; Preferably, the method further comprises: calcining the crystallized product to obtain the Recry-Beta molecular sieve; Preferably, the calcination conditions include: a calcination temperature of 400-650° C., more preferably 500-600° C.; and a calcination time of 2-8 h, more preferably 3 h-5 h.

6. Recry-Beta molecular sieve prepared by the method according to any one of claims 1 to 5; Preferably, the silicon-aluminum ratio of the Recry-Beta molecular sieve is above 800, more preferably 1200-2500; Preferably, the crystallinity of the Recry-Beta molecular sieve is 50-100%, more preferably 55-80%; Preferably, the BET specific surface area S of the Recry-Beta molecular sieve is BET 450-680m 2 / g, more preferably 500-660m 2 / g; Preferably, the total pore volume V of the Recry-Beta molecular sieve is 总 0.25-0.85cm 3 / g, more preferably 0.45-0.7cm 3 / g; Preferably, the stacking pore volume V of the Recry-Beta molecular sieve is meso 0.2-0.55cm 3 / g, more preferably 0.26-0.48cm 3 / g.

7. A method for preparing a catalyst, characterized in that: The method comprises: loading Zr onto the Recry-Beta molecular sieve as claimed in claim 6, and then drying and calcining to obtain the catalyst; Preferably, the loading method includes: impregnating the Recry-Beta molecular sieve with a Zr precursor solution; Preferably, the amount of each component is such that, based on the total weight of the catalyst, the content of Recry-Beta molecular sieve is 95-99.9wt%, more preferably 97-99.5wt%, and the content of zirconium-containing species calculated as Zr oxide is 0.1-5wt%, more preferably 0.5-3wt%; Preferably, the conditions for the immersion include: pH 3-12, more preferably 7-11; temperature 20-60°C; Preferably, the calcination conditions include: a temperature of 400-600° C. and a time of 1-6 hours.

8. A catalyst, characterized in that The catalyst comprises the Recry-Beta molecular sieve of claim 6 and a zirconium-containing species supported on the Recry-Beta molecular sieve; Preferably, based on the total weight of the catalyst, the content of Recry-Beta molecular sieve is 95-99.9wt%, more preferably 97-99.5wt%, and the content of zirconium-containing species calculated as Zr oxide is 0.1-5wt%, more preferably 0.5-3wt%.

9. The catalyst according to claim 8, wherein The crystallinity of the catalyst is 30-85%, preferably 40-75%; and / or The catalyst has a silicon to aluminum ratio of 800 or more, more preferably 1200-2500; and / or The BET specific surface area S of the catalyst BET 450-680m 2 / g, preferably 480-650m 2 / g; and / or The total pore volume V of the catalyst 总 0.35-0.7cm 3 / g, preferably 0.44-0.65cm 3 / g; and / or The catalyst has a bulk pore volume V meso 0.1-0.7cm 3 / g, preferably 0.2-0.55cm 3 / g.

10. Use of the Recry-Beta molecular sieve according to claim 6 or the catalyst according to claim 8 or 9 in a hydrocarbon conversion reaction, preferably in a reaction of preparing 1,3-butadiene from ethanol-acetaldehyde.

Images