Catalysts for the synthesis of 1,3-butadiene and their preparation methods, as well as methods for preparing 1,3-butadiene.

Abstract

The catalyst in this embodiment of the invention is a catalyst for the synthesis of 1,3-butadiene from ethanol. This catalyst comprises a porous silica support made of crystalline silica, Zn, and Zr, and has a peak pore size (D) of less than 2 nm. 微 ) and peak aperture greater than 2 nm (D 中+大 The multi-peaked pore size distribution.

Description

Technical Field

[0001] Embodiments of the present invention relate to catalysts for the synthesis of 1,3-butadiene from ethanol, methods for their preparation, and methods for preparing 1,3-butadiene using the catalyst. Background Technology

[0002] 1,3-Butadiene is widely used as a feedstock in the preparation of butadiene rubber (BR) or styrene-butadiene rubber (SBR). Currently, 1,3-Butadiene is mainly prepared by separating the C4 fraction from the steam cracking of crude gasoline to produce ethylene. In recent years, there has been a search for the synthesis of 1,3-Butadiene from feedstocks other than petroleum. As an alternative, a method for synthesizing 1,3-Butadiene from ethanol through direct conversion has been proposed.

[0003] For example, Patent Document 1 discloses a catalyst for obtaining butadiene by contacting ethanol, comprising a zeolite material having a framework structure containing YO2, wherein at least a portion of the Y contained in the framework structure is isomorphously replaced by element X. Preferably, Y is Si, Sn, Ti, Zr, or Ge, and X is preferably Zr, Ti, Sn, or Ta. Patent Document 1 also discloses that the zeolite material where Y is Si and X is Ti can further contain Zn as a non-framework element.

[0004] Patent Document 2 discloses a catalyst (ZnO / ZrO2 / MgO / SiO2) obtained by kneading and calcining magnesium hydroxide, colloidal silica, zinc nitrate and zirconium oxynitrate together with water as a catalyst for obtaining 1,3-butadiene from ethanol.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: WO2014 / 198901A1

[0008] Patent Document 2: WO2013 / 125389A1 Summary of the Invention

[0009] The technical problem to be solved by the present invention

[0010] The direct conversion of ethanol to 1,3-butadiene is one possible route. However, this direct conversion is a complex reaction requiring a dehydrogenation site, a Lewis acid site, and a mild Brønsted phase. A multifunctional catalyst for the part. However, with the conventional catalysts, the yield of 1,3-butadiene is not necessarily high, so efforts are being made to improve the yield.

[0011] The purpose of this invention is to provide a catalyst for the efficient synthesis of 1,3-butadiene from ethanol, a method for preparing the same, and a method for preparing 1,3-butadiene using the catalyst.

[0012] Technical means to solve technical problems

[0013] The present invention includes the embodiments shown below.

[0014] (1) A catalyst for the synthesis of 1,3-butadiene, comprising a porous silica support composed of crystalline silica, Zn and Zr, and having a first peak pore size (D) of less than 2 nm. 微 ) and a second peak aperture (D) greater than 2 nm 中+大 The multi-peaked pore size distribution.

[0015] (2) A method for preparing 1,3-butadiene, comprising: obtaining 1,3-butadiene from ethanol in the presence of a catalyst, wherein the catalyst comprises a porous silica support composed of crystalline silica, Zn and Zr, and has a first peak pore size (D) of less than 2 nm. 微 ) and a second peak aperture (D) greater than 2 nm 中+大 The multi-peaked pore size distribution.

[0016] (3) In (1) or (2) above, the catalyst comprises ZnO supported on the silica support as Zn, and also comprises Zr that has interacted with the silanol group of the silica support as Zr.

[0017] (4) In any of (1) to (3) above, the micropore volume (V) of the catalyst calculated using the t-plot method 微 The value is 0.03–0.30 cm. 3 / g, mesopore volume (V) calculated using the BJH method 中 The value is 0.30–2.0 cm. 3 / g.

[0018] (5) In any of (1) to (4) above, the silica support of the catalyst has an MFI-type framework structure.

[0019] (6) In any of (1) to (5) above, the molar ratio of Zn to Si in the catalyst is Zn / Si of 0.001 to 0.1 and the molar ratio of Zr to Si is Zr / Si of 0.05 to 0.5.

[0020] (7) In any of (1) to (6) above, the catalyst is a catalyst obtained by mixing zirconium alkoxide, orthosilicate and a first template agent together with water to prepare a zirconium silicate precursor, mixing the zirconium silicate precursor, zinc salt, orthosilicate and a second template agent together with water, and further performing hydrothermal synthesis and calcination.

[0021] (8) In (7) above, the first template agent is hexadecyltrimethylammonium bromide and the second template agent is tetrapropylammonium hydroxide.

[0022] (9) In (7) or (8) above, the catalyst is obtained by hydrothermal synthesis in the presence of a third template agent and calcination.

[0023] (10) In (9) above, the third template agent is glycerol.

[0024] (11) A method for preparing a catalyst for the synthesis of 1,3-butadiene, comprising: (i) mixing a zirconium alkoxide, an orthosilicate, and a first template agent for forming mesopores together with water to prepare a zirconium silicate precursor; (ii) mixing the zirconium silicate precursor, a zinc salt, an orthosilicate, and a second template agent for forming micropores together with water; (iii) performing hydrothermal synthesis using the resulting mixture; and (iv) calcining the reaction product obtained by the hydrothermal synthesis.

[0025] (12) In (11) above, the first template agent is hexadecyltrimethylammonium bromide and the second template agent is tetrapropylammonium hydroxide.

[0026] (13) In (11) or (12) above, a third template agent for forming macropores is added to the mixture and mixed, and the hydrothermal synthesis is performed using the mixture containing the third template agent.

[0027] (14) In (13) above, the third template agent is glycerol.

[0028] Invention Effects

[0029] According to embodiments of the present invention, 1,3-butadiene can be synthesized efficiently from ethanol. Attached Figure Description

[0030] Figure 1 The Zn 2p spectra of the ZnZrMFI catalyst and pure ZnO in Example 1 are shown.

[0031] Figure 2The Zr 3d spectra of the ZnZrMFI catalyst and pure ZrO2 in Example 1 are shown.

[0032] Figure 3 A graph showing the XRD results of the ZnZrMFI catalyst in Example 1.

[0033] Figure 4 A graph showing the pore size distribution of the catalyst in Example 1.

[0034] Figure 5 A graph showing the pore size distribution of the catalyst in Comparative Example 3.

[0035] Figure 6 The Zr 3d spectra of the catalyst of Comparative Example 3 and pure ZrO2 are shown.

[0036] Figure 7 This is a schematic diagram of the reaction apparatus used in the examples.

[0037] Figure 8 A graph showing the results of the stability test of the catalyst in Example 1. Detailed Implementation

[0038] The catalyst for the synthesis of 1,3-butadiene in this embodiment (hereinafter sometimes simply referred to as the catalyst) and the method for preparing 1,3-butadiene using the catalyst will be described below.

[0039] [Catalyst for the synthesis of 1,3-butadiene]

[0040] The catalyst in the embodiment is a catalyst for the synthesis of 1,3-butadiene from ethanol, which comprises a porous silica support, Zn and Zr.

[0041] The silica support is a porous crystal composed of crystalline silica with a three-dimensional pore structure. Therefore, compared to structures composed of amorphous silica, it has a larger specific surface area, which is beneficial for the dispersion of various active centers and can improve catalyst performance. Pores can be categorized as micropores, mesopores, and macropores. In one embodiment, the silica support has micropores, mesopores, and / or macropores. In this specification, micropores refer to pores with a diameter of 2 nm or less. Mesopores refer to pores with a diameter greater than 2 nm and less than 50 nm. Macropores refer to pores with a diameter greater than 50 nm.

[0042] The silica support has a framework structure comprising SiO2. This framework structure is essentially composed of SiO2, but a portion of the Si contained in the framework structure can be replaced by trivalent, tetravalent, and / or pentavalent elements such as aluminum. Preferably, the silica support has a framework structure of SiO2 without such substitution. As one embodiment, the silica support can also be an aluminum-free zeolite (i.e., dealuminolite).

[0043] The framework structure of the silica support is not particularly limited. Examples include MFI type, BEA type, FER type, MWW type, MOR type, FAU type, LTA type, and LTL type. It can have any one of these framework structures or a combination of two or more. In one embodiment, the silica support preferably has an MFI type framework structure.

[0044] In the aforementioned catalyst, zinc (Zn) is supported on a silica support in the form of an oxide, namely ZnO. Because the atomic radius of Zn is larger than that of Si, Zn does not enter the framework structure of the silica support during catalyst synthesis; instead, it is supported on the silica support as an oxide. It is believed that the ZnO supported on the silica support primarily promotes the dehydrogenation of ethanol.

[0045] In the above catalyst, zirconium (Zr) is mainly contained in a state where it has already interacted with the silanol groups (Si-OH) of the silica support. Since the atomic radius of Zr is larger than that of Si, Zr will not enter the framework structure of the silica support during the synthesis of the catalyst. Within the pores of the silica support, Zr interacts with the silanol groups on the SiO2 surface and forms Lewis active centers. The interaction between the silanol groups and Zr refers to the formation of a bond between the silanol groups and Zr. Specifically, it is preferable that Zr is coordinated with the silanol groups, and Zr forms a Si-O-Zr bond with the Si of the silanol groups, for example, in the form shown in the following formula (1), namely Zr(OH)(OSi)3.

[0046] [Chemical Formula 1]

[0047]

[0048] In the catalysts described above, Zr can be simply a substance that has already interacted with silanol groups, but a portion of Zr can also be supported on a silica support in the form of oxides, i.e., in the form of ZrO2. In one embodiment of the catalyst, Zr can be contained in the forms of Zr(OH)(OSi)3 and ZrO2.

[0049] The catalyst of this embodiment has a first peak pore size (D) of less than 2 nm. 微 ) and a second peak aperture (D) greater than 2 nm 中+大 The catalyst exhibits a multi-peaked pore size distribution. The peak pore size refers to the pore size at which the distribution curve reaches its maximum value, i.e., the pore size at the apex of the distribution curve. In the catalyst of this embodiment, there are peak pore sizes on both sides of a 2nm boundary; the peak pore size below 2nm is referred to as the first peak pore size (D). 微The peak aperture greater than 2 nm is called the second peak aperture (D). 中+大 This multi-modal pore size distribution is due to the catalyst having a structure that includes micropores as well as mesopores and / or macropores (hereinafter also referred to as a hierarchical pore structure), and more preferably, the catalyst has a hierarchical pore structure that includes micropores, mesopores, and macropores. By having a hierarchical pore structure, the mass transfer efficiency and tolerance to carbon precipitation are improved, and the stability of the catalyst is enhanced.

[0050] D 微 If the wavelength is 2nm or less as described above, there is no particular limitation. It is preferably 0.2nm or more and 1.5nm or less, more preferably 0.3nm or more and 1.0nm or less, and even more preferably 0.4nm or more and 0.8nm or less.

[0051] D 中+大 If the size is greater than 2nm as described above, there is no particular limitation. It is preferably 5nm or more and 1000nm or less, more preferably 10nm or more and 500nm or less, even more preferably 20nm or more and 300nm or less, and even more preferably 30nm or more and 100nm or less.

[0052] In the above catalysts, the micropore volume (V) calculated using the t-plot method is preferred. 微 The value is 0.03–0.30 cm. 3 / g, and the mesopore volume (V) calculated using the BJH method 中 The value is 0.30–2.0 cm. 3 / g. Through having such a micropore volume (V 微 ) and the volume of the central hole (V) 中 This can further enhance the effect achieved by having the above-mentioned multi-level porous structure.

[0053] V 微 More preferably, it is 0.04–0.20 cm. 3 / g, more preferably 0.05~0.10cm 3 / g. V 中 More preferably, it is 0.40–1.0 cm. 3 / g, more preferably 0.50~0.80cm 3 / g.

[0054] In the above catalyst, the molar ratio of zinc to silicon (Zn / Si) is not particularly limited, but is preferably 0.001 to 0.1. By making this molar ratio Zn / Si 0.001 or higher, the promoting effect of ethanol dehydrogenation can be improved. By making this molar ratio Zn / Si 0.1 or lower, ethanol dehydrogenation can be promoted without hindering the function of other active species. This molar ratio Zn / Si is preferably 0.005 or higher, more preferably 0.008 or higher. Furthermore, this molar ratio Zn / Si is preferably 0.05 or lower, more preferably 0.03 or lower.

[0055] In the above catalyst, the molar ratio of zirconium to silicon (Zr / Si) is not particularly limited, but is preferably 0.05 to 0.5. By setting this molar ratio of Zr / Si to 0.05 or higher, the promoting effect of aldol condensation and MPV reduction can be improved. By setting this molar ratio of Zr / Si to 0.5 or lower, the generation of byproducts can be suppressed. This molar ratio of Zr / Si is preferably 0.08 or higher, more preferably 0.1 or higher. Furthermore, this molar ratio of Zr / Si is preferably 0.4 or lower, more preferably 0.3 or lower.

[0056] [Preparation method of catalyst for 1,3-butadiene synthesis]

[0057] The preparation method of the above catalyst is not particularly limited, but it is preferred to use hydrothermal synthesis, and more preferably to use one-pot hydrothermal synthesis.

[0058] A preferred embodiment of the preparation method using hydrothermal synthesis includes the following steps:

[0059] (i) The process of preparing a zirconium silicate precursor by mixing zirconium alkoxide, orthosilicate and a first template agent for forming mesopores together with water;

[0060] (ii) The process of mixing the zirconium silicate precursor, zinc salt, orthosilicate and second template agent for forming micropores together with water;

[0061] (iii) The process of hydrothermal synthesis using the resulting mixture; and

[0062] (iv) A process of calcining the reaction product obtained by the hydrothermal synthesis.

[0063] If the preparation method includes the steps (i) to (iv) above, a multifunctional catalyst with various active centers such as dehydrogenation sites, Lewis acid sites, and mild Brønsted sites can be synthesized in a one-pot process. Furthermore, since the active centers can be uniformly dispersed, interactions between the active centers can be promoted. In addition, catalysts with hierarchical porous structures can be synthesized, particularly those where Zr interacts with silanol groups on the silica surface within the hierarchical pores to form Lewis active centers.

[0064] Orthosilicates used as silica sources in steps (i) and (ii) include, for example, tetraethoxysilane (TEOS), tetramethoxysilane (TEMOS), tetrapropoxysilane, tetrabutoxysilane, etc., and any one of them or a combination of two or more of them may be used.

[0065] As a zirconium alkoxide, there are no particular limitations. Examples include zirconium methoxide, zirconium ethanol, zirconium propoxide, and zirconium butoxide. Any one of these or a combination of two or more of them can be used.

[0066] As the first template agent, there are no particular limitations if it is a template agent capable of forming mesopores, but hexadecyltrimethylammonium bromide (CTAB) is preferred.

[0067] There are no particular limitations on what constitutes a zinc salt. For example, water-soluble zinc salts such as zinc acetate, zinc nitrate, zinc sulfate, zinc chloride, and zinc bromide can be used. Any one of these salts or a combination of two or more of them can be used.

[0068] As a second template agent, there are no particular limitations if it is a template agent capable of forming micropores; for example, tetrapropylammonium hydroxide (TPAOH) is preferred.

[0069] Step (i) is the process for synthesizing the zirconium silicate precursor. In the presence of a first template agent used to form mesopores, a mesoporous precursor can be synthesized by hydrolyzing the orthosilicate with a zirconium alkoxide. Additionally, in step (i), other components such as lower alcohols may be included when mixing the zirconium alkoxide, orthosilicate, first template agent, and water. Furthermore, in step (i), the zirconium silicate precursor is not calcined.

[0070] Specifically, in step (i), zirconium alkoxide and orthosilicate can be dissolved in a lower alcohol such as ethanol. The resulting solution is mixed with a first template agent and water, and the resulting first mixture is aged. During aging, in the presence of the first template agent, the orthosilicate hydrolyzes and undergoes dehydration condensation, while the zirconium alkoxide hydrolyzes, and Zr interacts with silanol groups to generate a mesoporous precursor. Then, by centrifugation and drying, a powder of the zirconium silicate precursor is obtained.

[0071] The amount of orthosilicate used in step (i) is not particularly limited, but is preferably 30 to 70% by mass, more preferably 40 to 60% by mass, relative to the total amount of orthosilicate used in steps (i) and (ii).

[0072] The amount of zirconium alkoxide used is not particularly limited. The molar ratio of zirconium to silicon, Zr / Si, is preferably 0.05 to 0.5, more preferably 0.08 to 0.4, and even more preferably 0.1 to 0.3, relative to the total amount of orthosilicate used in steps (i) and (ii).

[0073] The amount of the first template agent is not particularly limited. It can be 10 to 80 parts by mass or 20 to 40 parts by mass relative to the total amount of orthosilicate used in steps (i) and (ii) of 100 parts by mass.

[0074] In step (ii), the second precursor is synthesized by adding an additional silica source along with the zirconium silicate precursor obtained in step (i).

[0075] Specifically, in step (ii), the zinc salt and orthosilicate can be dissolved in a lower alcohol such as ethanol, while a zirconium silicate precursor is added and mixed. A second template agent and water are then added to the resulting mixture and mixed. Thus, in the presence of the zinc salt, the zirconium silicate precursor, and the second template agent, the orthosilicate hydrolyzes and undergoes dehydration condensation to generate the ZnZr silicate precursor.

[0076] The amount of zinc salt used is not particularly limited. The molar ratio of zinc to silicon, Zn / Si, is preferably 0.001 to 0.1, more preferably 0.005 to 0.05, and even more preferably 0.008 to 0.03, relative to the total amount of orthosilicate used in steps (i) and (ii).

[0077] The amount of the second template agent is not particularly limited. It can be 50 to 130 parts by mass or 80 to 100 parts by mass relative to the total amount of orthosilicate used in steps (i) and (ii) of 100 parts by mass.

[0078] In step (ii), lower alcohols may also be removed by distillation from a mixture containing the ZnZr silicate precursor thus obtained.

[0079] Then, the hydrothermal synthesis of step (iii) can be carried out directly, or a third template agent can be added before hydrothermal synthesis. That is, in one embodiment, a third template agent for forming macropores can be added to and mixed into a mixture containing the ZnZr silicate precursor, and the hydrothermal synthesis of step (iii) can be carried out using the mixture containing the third template agent. By adding the third template agent, larger macropores can be formed.

[0080] As a third template agent, there are no particular limitations if it is capable of forming macropores; for example, glycerol is preferred. Hydrothermal synthesis in the presence of glycerol can significantly reduce the particle size of the catalyst, which is beneficial for improving mass transfer efficiency.

[0081] The amount of the third template agent is not particularly limited. It can be 10 to 80 parts by mass or 30 to 50 parts by mass relative to the total amount of orthosilicate used in steps (i) and (ii) of 100 parts by mass.

[0082] In step (iii), the mixture obtained in step (ii) is used for hydrothermal synthesis. Hydrothermal synthesis is a reaction carried out in the presence of hot water at high temperature and pressure, resulting in further dehydration condensation to generate silica. At this time, the presence of a first template agent and a second template agent (preferably a third template agent) forms pores with corresponding pore sizes, creating a hierarchical porous structure. Furthermore, since one-pot hydrothermal synthesis is performed, Zn and Zr, as active centers, can be uniformly dispersed in the silica support, promoting interactions between the active centers.

[0083] Hydrothermal synthesis can be carried out, for example, using an autoclave. There are no particular limitations on the processing conditions; for example, it can be carried out at 150–180°C for 24–96 hours at the pressure naturally generated by volume expansion.

[0084] After hydrothermal synthesis, the resulting reaction product is dried, and then calcined in step (iv). This yields a catalyst according to one embodiment. The calcination temperature is not particularly limited, but can be, for example, 300–700°C or 400–600°C. After calcination, the product can be pulverized and further granulated or molded as needed.

[0085] [Preparation method of 1,3-butadiene]

[0086] The method for preparing 1,3-butadiene according to this embodiment includes obtaining 1,3-butadiene from ethanol in the presence of the catalyst described in this embodiment. For this purpose, it is only necessary to contact the ethanol-containing feedstock with the catalyst described above.

[0087] The route for synthesizing 1,3-butadiene from ethanol using this catalyst is not particularly limited, and is generally considered to be as follows: (1) ethanol is dehydrogenated to acetaldehyde, (2) acetaldehyde is condensed with aldol to butanol, (3) butanol is dehydrated to crotonaldehyde, (4) crotonaldehyde and ethanol are reduced together by MPV to crotonol, and (5) crotonol is dehydrated to 1,3-butadiene.

[0088] The ethanol used in the preparation is not particularly limited; for example, it can be bioethanol generated from biomass or ethanol synthesized from the hydration reaction of ethylene from fossil fuels. The above-mentioned raw materials may contain other components such as acetaldehyde along with ethanol.

[0089] The method of contacting the catalyst with the ethanol-containing feedstock is not particularly limited if it is a method that can convert ethanol to 1,3-butadiene in the presence of the catalyst; it can be carried out in the gas phase or in the liquid phase. Preferably, the ethanol-containing feedstock is prepared as a gas and the gas is passed through a catalyst bed containing the catalyst to carry out the reaction in the gas phase.

[0090] When the reaction is carried out in the gas phase, the raw material gas can be supplied to the reaction system without dilution, or it can be diluted with inactive gases such as nitrogen or argon and then supplied to the reaction system.

[0091] The reaction temperature (temperature of the catalyst bed) is not particularly limited if it is the temperature at which ethanol is converted into 1,3-butadiene; for example, it can be 250–500°C or 300–400°C. The reaction pressure is also not particularly limited; for example, it can be atmospheric pressure to 1 MPa.

[0092] The reaction can be either continuous flow or batch. In the continuous flow type, the weight-time-space velocity (WHSV), which is the ratio of feed rate (weight / time) to catalyst weight, is not particularly limited; for example, it can be 0.1 to 10 h. -1 It can also be 0.3 to 2 hours. -1 .

[0093] There are no particular restrictions on the reaction method; it can be any of the fixed-bed, moving-bed, or fluidized-bed reactors. There are also no particular restrictions on the reactor type; for example, tubular reactors can be used.

[0094] The product obtained after the reaction can be purified by distillation or other methods as needed. This allows for the removal of unreacted ethanol or byproducts such as ethylene, ether, and acetaldehyde.

[0095] Example

[0096] Although embodiments are shown below, the present invention is not limited to these embodiments.

[0097] [Example 1: Preparation of ZnZrMFI catalyst]

[0098] 2.60 g of tetraethoxysilane (TEOS) and 2.40 g of zirconium butoxide (Zr(OBu)4) were added to 10 mL of ethanol and stirred until dissolved. The resulting solution was added to an aqueous solution of 1.91 g of hexadecyltrimethylammonium bromide (CTAB) dissolved in 300 mL of water and allowed to mature overnight. Then, the solution was centrifuged and dried at 100 °C for 12 hours to obtain the zirconium silicate precursor.

[0099] 0.05 g of zinc acetate (Zn(CH3COO)2·2H2O) and 2.61 g of TEOS were added to 10 mL of ethanol and stirred for 1 hour to dissolve. 1.00 g of zirconium silicate precursor was added and stirred for 1 hour, followed by 5.08 g of tetrapropylammonium hydroxide (TPAOH) and 18.69 g of water, and the mixture was stirred for 4 hours. The resulting mixture was heated at 90 °C for 4 hours to distill off the ethanol, and then 2.30 g of glycerol was added and mixed. The mixture was then transferred to a stainless steel autoclave lined with fluororesin and subjected to a hydrothermal synthesis reaction at 130 °C and the pressure naturally generated by volume expansion for 48 hours. The resulting reaction product was dried at 100 °C for 12 hours and then calcined in air at 550 °C for 5 hours to obtain the ZnZrMFI catalyst (molar ratio Zn / Si = 0.01, molar ratio Zr / Si = 0.2).

[0100] The obtained ZnZrMFI catalyst was analyzed by X-ray photoelectron spectroscopy (XPS) using an Al Ka ​​X-ray source on an ESCALAB 250Xi system manufactured by Thermo Fisher Scientific Inc. This yielded... Figure 1 The Zn 2p spectrum shown is similar to Figure 2 The Zr 3d spectrum is shown. Furthermore, the crystal structure of the ZnZrMFI catalyst was determined using X-ray diffraction (XRD) (CuKα 40 kV, 20 mA, 6°–60°), yielding... Figure 3 The measurement results are shown.

[0101] about Figure 2 The binding energy of the Zr 3d peak shown is observed in pure ZrO2, where two peaks are observed. On the other hand, in the ZnZrMFI catalyst (Zn... 0.01 Zr 0.2 In the MFI, the binding energy of the Zr 3d peak shifts to a higher energy side compared to pure ZrO2, indicating that Zr interacts with silanol groups to form Si-O-Zr bonds. Figure 6 The catalyst (Zn) of Comparative Example 3 described later will be considered. 0.01 Zr 0.2 The Zr 3d spectrum of MFI(mi) is shown together with the Zr 3d spectrum of pure ZrO2. In the catalyst of Comparative Example 3, the two peaks are respectively the two main peaks corresponding to Si-O-Zr and the two weak peaks corresponding to ZrO2. It can be seen that the synthesis method via zirconium silicate precursor in Example 1 can further enhance the interaction between Zr and silanol groups and further suppress the production of ZrO2.

[0102] about Figure 1The binding energy of the Zn 2p peak shown is compared with that of pure ZnO to that of the ZnZrMFI catalyst (Zn 0.01 Zr 0.2 The peak of MFI did not change significantly, indicating that it exists in the form of ZnO.

[0103] In addition, such as Figure 3 As shown, the ZnZrMFI catalyst (Zn 0.01 Zr 0.2 MFI has a peak characteristic of MFI, indicated by "×".

[0104] As can be seen from the above, the prepared ZnZrMFI catalyst contains a silica support with an MFI-type framework structure, Zn is supported on the silica support in the form of ZnO, and Zr is contained in the form of Zr(OH)(OSi)3.

[0105] [Comparative Example 1: Preparation of ZnCe / beta catalyst]

[0106] 5.0 g of H-beta ("941HOA" manufactured by TOSOH CORPORATION) was added to 100 mL of 13 mol / L nitric acid, stirred at 100 °C for 12 hours, then filtered and washed to obtain Si-beta. 5 g of Si-beta, 0.96 g of Zn(NO3)2·6H2O, and 0.66 g of Ce(NO3)3·6H2O were mixed and micronized, then calcined in air at 500 °C for 6 hours. This yielded a ZnCe / beta catalyst (Zn content = 5.0 wt%, Ce content = 5.0 wt%).

[0107] [Comparative Example 2: Preparation of ZrMFI Catalyst]

[0108] Solution A was prepared by dissolving 1.91 g of CTAB in 300 mL of deionized water while stirring. Solution B was prepared by mixing 2.60 g of TEOS and 2.40 g of Zr(OBu)₄ with 10 mL of ethanol while stirring. Solution B was slowly added to solution A while stirring, and the mixture was allowed to mature overnight. The solid product was centrifuged at 2500 rpm and dried at 60 °C overnight to obtain the zirconium silicate precursor.

[0109] A mixed solution was prepared by adding 2.60 g of TEOS to 10 mL of ethanol. The zirconium silicate precursor was added to the mixed solution and stirred for 1 hour. Then, 5.08 g of TPAOH and 18.69 g of H₂O were added dropwise to the mixed solution while stirring. The mixture was continuously stirred at 700 rpm for 4 hours, followed by heating at 90 °C for 4 hours to remove almost all water and ethanol from the mixture. After gel formation, it was mixed with 2.30 g of glycerol and then transferred to a stainless steel autoclave lined with fluoropolymer for hydrothermal synthesis at 130 °C for 48 hours. The product was dried at 100 °C for 12 hours and then calcined in air at 550 °C for 5 hours to obtain Zr. 0.2 MFI catalyst.

[0110] [Comparative Example 3: Preparation of ZnZrMFI(mi) catalyst]

[0111] 0.05 g of Zn(CH3COO)2·2H2O and 5.21 g of TEOS were added to 10 mL of ethanol and stirred for 1 hour to dissolve. 2.40 g of Zr(OBu)4 was added and stirred for 1 hour, followed by the addition of 5.08 g of TPAOH and 18.69 g of water, and the mixture was stirred for 4 hours. The resulting mixture was heated at 90 °C for 4 hours to distill off the ethanol, and then transferred to a stainless steel autoclave lined with fluororesin. A hydrothermal synthesis reaction was carried out at 130 °C under pressure generated naturally by volume expansion for 48 hours. The resulting reaction product was dried at 100 °C for 12 hours and then calcined in air at 550 °C for 5 hours to obtain the ZnZrMFI(mi) catalyst (molar ratio Zn / Si = 0.01, molar ratio Zr / Si = 0.2).

[0112] [Determination of pore size and pore volume]

[0113] The pore sizes of the ZnZrMFI catalyst of Example 1 and the ZnZrMFI(mi) catalyst of Comparative Example 3 were measured, and the peak pore size (D) was determined based on the pore size distribution. 微 D 中+大 Furthermore, the micropore volume (V) is calculated as the pore volume. 微 ) and the volume of the central hole (V) 中 The determination method is shown below.

[0114] Using the catalyst as a sample, nitrogen (N2) adsorption and desorption were measured using a "3Flex2MP" instrument manufactured by Micromeritics Instrument Corporation. Prior to the measurement, the sample was degassed under vacuum at 350°C for 5 hours.

[0115] This measuring apparatus utilizes the HK method to analyze the pore size distribution of micropores and the BJH method to analyze the pore size distribution of mesopores and macropores. The pore size distribution is determined by measuring the Log differential pore volume distribution (dV / dlogD). Figure 4 As shown, this pore size distribution uses pore size as the horizontal axis and dV / dlogD as the vertical axis. dV / dlogD is the value obtained by dividing the differential pore volume dV by the logarithm of the pore size, d(logD), and is plotted against the average pore size of each interval. Based on the obtained pore size distribution, the peak pore size (D) of the micropores is calculated. 微 ) and the peak aperture (D) of medium and large holes 中+大 ).

[0116] In addition, the micropore volume (V) was calculated using the t-plot method. 微 The volume of the central hole (V) was calculated using the BJH method. 中 ).

[0117] The pore size distributions of the catalysts in Example 1 and Comparative Example 3 are shown in the figure. Figure 4 and Figure 5 .like Figure 5 As shown, in the catalyst of Comparative Example 3, D 微 A single peak aperture of 0.54 nm. In contrast, as... Figure 4 As shown, in the catalyst of Example 1, there is D 微 =0.55nm and D 中+大 The catalyst exhibits a multi-peak pore size distribution with two peak pore sizes of 50.18 nm. Furthermore, the catalyst of Example 1 has micropores with a pore size of less than 2 nm, mesopores with a pore size greater than 2 nm and less than 50 nm, and macropores with a pore size greater than 50 nm, demonstrating a multi-level nanoscale pore size distribution.

[0118] Furthermore, as shown in Table 1 below, compared with the catalyst of Comparative Example 3, the mesopore volume V of the catalyst of Example 1 is... 中 Larger, with micropore volume V 微 Total pore volume V 总 It is also quite large.

[0119] [Catalyst Performance Evaluation Test]

[0120] The catalysts prepared above were subjected to catalyst performance evaluation tests based on the reaction of ethanol to synthesize 1,3-butadiene. The synthesis reaction was carried out in a quartz fixed-bed flow reactor with an inner diameter of 4 mm under atmospheric pressure.

[0121] A schematic diagram of the reaction apparatus is shown below. Figure 7 As shown. In Figure 7In the figure, reference numeral 12 indicates a nitrogen cylinder that supplies nitrogen as a carrier gas, reference numeral 14 indicates an injection pump that supplies ethanol, reference numeral 16 indicates a mass flow controller (MFC), reference numeral 18 indicates an evaporator, and reference numeral 20 indicates a strip heater that serves as a pipeline heater for heating the outer periphery of the gas flow pipeline.

[0122] Reference numeral 22 indicates a fixed-bed flow-through reactor, reference numeral 24 indicates a catalyst bed inside reactor 22, reference numeral 26 indicates an electric furnace for heating reactor 22, and reference numeral 28 indicates a thermocouple thermometer (TC) for detecting the temperature of catalyst bed 24.

[0123] Reference numeral 30 indicates the pipeline through which the gas flows through reactor 22; reference numeral 32 indicates the bypass passage that bypasses reactor 22; reference numeral 34 indicates the gas chromatograph (GC) used for analyzing gaseous products; reference numeral 36 indicates the exhaust outlet; and reference numeral 38 indicates the six-way valve that switches the flow paths of the aforementioned pipeline 30, bypass passage 32, GC 34, and exhaust outlet 36.

[0124] 0.5 g of catalyst was packed into reactor 22 to form a catalyst bed 24. Quartz wool 40 was packed and fixed on both sides of the catalyst bed 24. Nitrogen gas was introduced into reactor 22 from nitrogen cylinder 12 via MFC 16 at a flow rate of 20 mL / min, and pretreated at 400°C for 1 hour. After cooling to 350°C, ethanol (WHSV = 0.38 h⁻¹) was introduced into the reaction system using syringe pump 14 at a rate of 0.24 mL / h (using nitrogen gas as a carrier gas, introduced at a rate of 20 mL / min for dilution). -1 The catalyst evaluation was conducted over 6 hours.

[0125] The gaseous products discharged from reactor 22 are introduced into gas chromatograph (GC) 34 in an online manner, and the gaseous products are analyzed using a gas chromatograph (Shimadzu GC-14B manufactured by Shimadzu Corporation and DB-1 column (30m×0.25mm×0.25μm) manufactured by GL Sciences Inc.) and a flame ionization detector (FID).

[0126] The following shows the formulas for calculating the conversion rate (ethanol conversion rate), the selectivity of each product, and the yield (yield of 1,3-butadiene).

[0127] [Mathematical Expression 1]

[0128]

[0129]

[0130] n in the formula 乙醇，入 With n 乙醇，出 These represent the mole fractions of ethanol before and after the reaction, respectively.

[0131] A ri with f im These represent the area ratio and the quality correction factor of the chromatogram, respectively.

[0132] Yield (%) = Conversion (%) × 1,3-Butadiene selectivity (%) / 100

[0133]

[0134] The results are shown in Table 1. 1,3-Butadiene, ethylene, acetaldehyde, diethyl ether, and other coupling products were detected. When using the catalyst of Example 1, the conversion of ethanol and the yield of 1,3-butadiene were significantly improved compared to the ZnCe / beta catalyst of Comparative Example 1 and the ZnMFI catalyst of Comparative Example 2. Furthermore, compared to Comparative Example 3, which used a ZnZrMFI(mi) catalyst without a hierarchical porous structure, the selectivity for 1,3-butadiene was significantly improved, and the yield of 1,3-butadiene was also significantly improved. Therefore, according to Example 1, 1,3-butadiene can be synthesized efficiently.

[0135] [Catalyst stability test]

[0136] In the catalyst stability test, the catalyst of Example 1 was subjected to the above-mentioned catalyst performance evaluation test for 80 hours, and the conversion rate (ethanol conv.) and 1,3-butadiene selectivity (butadiene sel.) were measured every hour during the day.

[0137] The results are as follows Figure 8 As shown, the catalyst in Example 1 exhibits excellent stability.

[0138] Furthermore, the upper and lower limits of the various numerical ranges described in this specification can be arbitrarily combined, and all such combinations are considered to be preferred numerical ranges described in this specification. Additionally, the description of the numerical range "X~Y" refers to values ​​above X and below Y.

[0139] The foregoing has described some embodiments of the present invention, but these embodiments are mentioned only as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the present invention. These embodiments, as well as their omissions, substitutions, and modifications, are included within the scope and spirit of the invention, and are also included within the scope of the invention described in the claims and their equivalents.

Claims

1. A catalyst for the synthesis of 1,3-butadiene, comprising a porous silica support composed of crystalline silica, Zn, and Zr. And has a first peak aperture (D) of less than 2 nm. 微 ) and a second peak aperture (D) above 20 nm and below 300 nm 中+大 The multi-peaked pore size distribution in, The micropore volume (V) calculated using the t-plot method 微 The value is 0.03~0.30cm. 3 / g, the volume of the mesopore (V) calculated using the BJH method 中 The value is 0.40~2.0cm. 3 / g; the crystalline silica has micropores with a pore size of less than 2nm, mesopores with a pore size of greater than 2nm and less than 50nm, and macropores with a pore size of greater than 50nm. The catalyst is obtained by mixing zirconium alkoxide, orthosilicate, and a first template agent with water to prepare a zirconium silicate precursor, and then mixing the zirconium silicate precursor, zinc salt, orthosilicate, and a second template agent with water, followed by hydrothermal synthesis and calcination.

2. The catalyst for the synthesis of 1,3-butadiene according to claim 1, comprising ZnO supported on the silica support as Zn and Zr comprising Zr that has interacted with the silanol group of the silica support as Zr.

3. The catalyst for the synthesis of 1,3-butadiene according to claim 1 or 2, wherein, The silica carrier has an MFI-type framework structure.

4. The catalyst for the synthesis of 1,3-butadiene according to claim 1 or 2, wherein, The molar ratio of Zn to Si (Zn / Si) is 0.001~0.1, and the molar ratio of Zr to Si (Zr / Si) is 0.05~0.

5.

5. The catalyst for the synthesis of 1,3-butadiene according to claim 1 or 2, wherein, The first template agent is hexadecyltrimethylammonium bromide, and the second template agent is tetrapropylammonium hydroxide.

6. The catalyst for the synthesis of 1,3-butadiene according to claim 1 or 2, wherein, The catalyst is obtained by hydrothermal synthesis in the presence of a third template agent followed by calcination.

7. The catalyst for the synthesis of 1,3-butadiene according to claim 6, wherein, The third template agent is glycerol.

8. A method for preparing 1,3-butadiene, comprising obtaining 1,3-butadiene from ethanol in the presence of a catalyst, said catalyst comprising a porous silica support composed of crystalline silica, Zn and Zr, and having a first peak pore size (D) of less than 2 nm. 微 ) and a second peak aperture (D) above 20 nm and below 300 nm 中+大 The multi-peaked pore size distribution in, The catalyst's micropore volume (V) was calculated using the t-plot method. 微 The value is 0.03~0.30cm. 3 / g, the volume of the mesopore (V) calculated using the BJH method 中 The value is 0.40~2.0cm. 3 / g; the crystalline silica has micropores with a pore size of less than 2nm, mesopores with a pore size of greater than 2nm and less than 50nm, and macropores with a pore size of greater than 50nm. The catalyst is obtained by mixing zirconium alkoxide, orthosilicate, and a first template agent with water to prepare a zirconium silicate precursor, and then mixing the zirconium silicate precursor, zinc salt, orthosilicate, and a second template agent with water, followed by hydrothermal synthesis and calcination.

9. The method for preparing 1,3-butadiene according to claim 8, wherein, The catalyst comprises ZnO supported on the silica support as Zn and Zr comprising Zr that has interacted with the silanol groups of the silica support as Zr.

10. The method for preparing 1,3-butadiene according to claim 8 or 9, wherein, The silica support of the catalyst has an MFI-type framework structure.

11. A method for preparing a catalyst for the synthesis of 1,3-butadiene, comprising: A zirconium silicate precursor was prepared by mixing zirconium alkoxide, orthosilicate, and a first template agent for forming mesopores together with water. The zirconium silicate precursor, zinc salt, orthosilicate, and second template agent for forming micropores are mixed together with water; The resulting mixture was used for hydrothermal synthesis; and The reaction products obtained through the hydrothermal synthesis are calcined.

12. The method for preparing the catalyst for the synthesis of 1,3-butadiene according to claim 11, wherein, A third template agent for forming macropores is added to the mixture and mixed, and the hydrothermal synthesis is performed using the mixture containing the third template agent.

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