Pore ​​expansion in mesoporous Y-type materials

Abstract

This invention provides a method for preparing a mesoporous Y-zeolite catalyst having a larger mesopore diameter. The method utilizes a swelling agent and optionally a co-solvent. Larger mesopores improve accessibility for mass transfer of bulky reactants. In the preparation, the swelling agent is used in combination with cetyltrimethylammonium bromide (CTAB). A co-solvent may also be used to influence the strong swelling effect.

Description

[Technical Field]

[0001] Cross-reference of related applications This application was filed as a PCT international application on 25 April 2024, claiming priority to U.S. Patent Application No. 18 / 644,306, filed on 24 April 2024, and further claims the benefit of U.S. Provisional Patent Application No. 63 / 499,669, filed on 2 May 2023, the disclosures thereof incorporated herein by reference in their entirety. [Background technology]

[0002] background The surfactant templating method is widely used in the synthesis of mesoporous silica, as exemplified by the successful synthesis of arranged mesoporous molecular sieves (MCM-41) with pore sizes ranging from 2 nm to 10 nm, using cetyltrimethylammonium bromide (CTAB) as a template under basic conditions. Early analysis based on Raman spectroscopy showed that these materials are amorphous, i.e., non-crystalline. This method provided a rational way to control mesopore size by increasing the alkyl chain length of the surfactant. Furthermore, swelling agents such as 1,3,5-trimethylbenzene (TMB), 1,3,5-triisopropylbenzene, isopropylbenzene, tridecane, and paraxylene (p-xylene) have been shown to modify the textured properties of the resulting mesoporous silicate and to expand the pore size of MCM-41 material up to 20 nm. In particular, both TMB and p-xylene are widely used as swelling agents to increase the mesopore size of micelle-templated silica (MTS). These two swelling agents are C 16 This is compared in MTS synthesis using TAB surfactant aggregates. When TMB is used as a swelling agent, TMB / C 16It has been reported that as the TAB ratio increases in the range from 0 to 13, the MTS mesopore size increases from 3.9 nm to 9.0 nm (TMB / C 16 A plateau is observed at 8.5 nm when the TAB ratio is 5). When p-xylene is used as the swelling agent, the same authors reported that for p-xylene / C 16 reported a mesopore size of 3.9 nm at a TAB ratio of 2, and that increasing this ratio in the range from 5 to 20 results in further mesopore growth, generating a bimodal mesopore size distribution in the range from 8.0 nm to 16.5 nm.

[0003] Following the successful synthesis of MCM-41S-type materials, the surfactant templating approach has been extended to the synthesis of other materials such as mesoporous polymers, mesoporous metal oxides, and mesoporous metal organic frameworks (MOFs). Among these, the synthesis of mesoporous zeolites has attracted much attention because the surfactant templating approach provides a method for introducing mesoporosity into zeolites while retaining the strong acidity and high hydrothermal stability of zeolites. In particular, Garcia-Martinez et al. reported the synthesis of mesoporous Y-type zeolites starting from Y-type zeolites (CBV720 from Zeolyst, Si / Al ratio = 15) and using a surfactant templating approach that combines the formation of a mesoporous phase using trimethylalkylammonium bromide (C n TAB, n = 16 and 18) as the surfactant in the presence of NH4OH (or other bases such as NaOH, Na2CO3 or tetrapropylammonium hydroxide (TPAOH)). Their results show that when C 16 TAB is used as the surfactant, a mesopore size of approximately 3.8 nm is generated, and the carbon chain length of the alkyl chain in the surfactant (C8TAB, C 10 TAB, C 12 TAB, C 14 TAB, C 16 TAB and C 18This shows that it can be increased by increasing TAB. By using this method, C 22 When TAB is used as a surfactant, the mesopore size of the mesoporous Y-type zeolite is increased to a maximum of 5.3 nm. A similar method for adjusting the surfactant size is used with (CH3O)3SiC3H6N + (CH3)2C n H 2n+1 When used as a surfactant, it is also used to control the mesoporosity in ZSM-5 zeolite.

[0004] Octadecyltrimethylamonium bromide (C 18 The effect of the NaOH / SiO2 ratio on the mesoporosity of synthetic samples using TAB as a surfactant has also been studied. The data show that amorphous walls are obtained when the NaOH / SiO2 ratio is in the range of 0.125 to 0.25 in mesoporous Y-type zeolite synthesis. Furthermore, it has been shown that increasing the NaOH / SiO2 ratio from 0.05 to 0.25 reduces the mesopore size from 4.30 nm to 3.91 nm. This indicates that the NaOH concentration has little effect on the mesopore size, but results in a larger mesopore volume, smaller zeolite nanodomains, lower acidity, and lower micropore volume.

[0005] The addition of cosolvents is also widely used in MTS systems to increase mesopore size. The physicochemical properties of the cosolvent (e.g., its polarity and dielectric constant), as well as its quantity, have been reported to affect d-spacing, mesopore size, mesophase transitions, and the morphology of mesoporous silica. Furthermore, the effect of cosolvents in combination with surfactant templating techniques has been previously investigated in the synthesis of mesoporous zeolites, including Y-type zeolites, ZSM-5 zeolites, and NaX zeolites. All of these utilize a bottom-up approach. 16We have used TAB surfactant templating (i.e., modification after synthesis of zeolite or zeolite precursor), demonstrating that the cosolvent plays different roles, including acting as a self-assembly modifier in addition to being a mesopore size expander. However, reports of using a cosolvent in the presence of a swelling agent in surfactant templating synthesis remain rare. [Overview of the project]

[0006] overview A method is provided for preparing mesoporous Y-type zeolite catalysts having larger mesopore sizes. This method uses a swelling agent and optionally a cosolvent. Larger mesopores improve accessibility for mass transfer of bulky reactants.

[0007] In preparation, a swelling agent is used in combination with cetyltrimethylammonium bromide (CTAB). This combination of materials increases the mesopore size of the Y-type material to 6.8 nm or larger, and the mesopore volume to a maximum of 0.41 cm³. 2 It has been found that the limit is up to / g. Cosolvents can also be used to influence the strong swelling effect.

[0008] The swelling agent may be any suitable swelling agent. In one embodiment, the swelling agent may include 1,3,5-trimethylbenzene (TMB) or para-xylene (p-xylene). In one embodiment, a co-solvent is also used. The co-solvent may be any suitable co-solvent for promoting a strong swelling effect. The co-solvent in this method is generally an alcohol. In one embodiment, the co-solvent may include ethanol or tert-butanol (TBA) tert-butyl alcohol.

[0009] Among other factors, the use of swelling agents, optionally with a co-solvent such as an alcohol, has been found to enlarge the mesopore size of mesoporous Y-type zeolites using CTAB as a template. The use of swelling agents in the synthesis of Y-type zeolites has been found to enlarge the mesopore size. In one embodiment, the use of TMB provides excellent results. The addition of a co-solvent such as an alcohol co-solvent can further enlarge the mesopore size. In one embodiment, TBA as a co-solvent provides excellent results. [Brief explanation of the drawing]

[0010] The attached drawings, by reference, constitute part of this specification and illustrate several aspects of this disclosure. A brief description of the drawings is as follows:

[0011] [Figure 1A] Figure 1A shows the nitrogen physicoadsorption isotherm at 77K when using TMB.

[0012] [Figure 1B] Figure 1B illustrates the DFT pore size distribution of samples synthesized using different TMB / C16TAB ratios.

[0013] [Figure 1C] Figure 1C illustrates the change in the maximum mesopore size with respect to the TMB / C16TAB ratio.

[0014] [Figure 1D] Figure 1D illustrates the nitrogen physicoadsorption isotherm at 77K when p-xylene is used.

[0015] [Figure 1E] Figure 1E illustrates the DFT pore size distribution of samples synthesized using different p-xylene / C16TAB ratios.

[0016] [Figure 1F] Figure 1F illustrates the change in the maximum mesopore size with respect to the p-xylene / C16TAB ratio.

[0017] [Figure 2A] Figure 2A shows the nitrogen physicoadsorption isotherm at 77K when ethanol is used.

[0018] [Figure 2B] Figure 2B illustrates the DFT pore size distribution of samples synthesized using different ethanol / TMB / C16TAB ratios.

[0019] [Figure 2C] Figure 2C illustrates the maximum pore size distribution D (nm) with and without ethanol addition at different TMB amounts.

[0020] [Figure 2D] Figure 2D illustrates the nitrogen physicoadsorption isotherm at 77K when TBA is used.

[0021] [Figure 2E] Figure 2E illustrates the DFT pore size distribution of samples synthesized using different TAB / TMB / TBA ratios.

[0022] [Figure 2F] Figure 2F illustrates the maximum pore size distribution D (nm) with and without TBA addition at different TMB concentrations.

[0023] [Figure 3A] Figure 3A illustrates the nitrogen physicoadsorption isotherm for C18TAB at 77K.

[0024] [Figure 3B]Figure 3B illustrates the DFT pore size distribution of samples using different ratios of the swelling agent TMB / C18TAB.

[0025] [Figure 3C] Figure 3C illustrates a comparison of the maximum pore size distribution D (nm) using C18TAB and the maximum mesopore size distribution D (nm) using C16TAB.

[0026] [Figure 3D] Figure 3D illustrates the maximum distribution D (nm) for materials synthesized using C16TAB and C18TAB.

[0027] [Figure 4A] Figure 4A illustrates the nitrogen physicoadsorption isotherm at 77K.

[0028] [Figure 4B] Figure 4B illustrates the DFT pore size distribution of different samples.

[0029] [Figure 4C] Figure 4C illustrates the maximum pore size distribution when ethanol and TBA are added as cosolvents. [Modes for carrying out the invention]

[0030] Before disclosing and describing the process for achieving pore expansion in mesoporous materials, it should be understood that this disclosure is not limited to the specific structures, process steps, or materials disclosed herein, but extends to their equivalents as commonly recognized by those skilled in the art. It should also be understood that the terms used herein are for the purpose of describing specific embodiments and are not intended to limit them. It should be noted that the singular forms “a,” “an,” and “the” used herein include plural references unless the context explicitly indicates otherwise. Therefore, for example, a reference to “a step” may include multiple steps, a reference to “products” or “producing” of a reaction or treatment should not be interpreted as meaning all products of the reaction / treatment, and a reference to “treating” may include a reference to one or more such treatment steps. Thus, a treating step may include multiple or repeated treatments of a similar material / fluid to produce a specified treatment product.

[0031] Numerical values ​​accompanied by "about" encompass typical experimental variability. As used herein, "about" means a statistically meaningful range for a stated value such as particle size, concentration range, time frame, molecular weight, temperature, or pH. Such a range may be within one order of magnitude, typically within 10% of the indicated value or range, and more preferably within 5%. In some cases, such a range may be within the typical experimental error of the standard method used to measure and / or determine a given value or range. The acceptable variability encompassed by the term "about" depends on the specific system under consideration and is readily understandable to a person ordinarily skilled in the art. Whenever a range is described herein, all integer values ​​within that range are also intended as embodiments of the present invention.

[0032] A method is provided for preparing mesoporous Y-type zeolite catalysts having larger mesopore sizes. This method uses a swelling agent and optionally a cosolvent. Larger mesopores improve access for mass transfer of bulky reactants.

[0033] The exemplary embodiments of this disclosure illustrated in the attached drawings will be described in detail below.

[0034] The swelling agent, co-solvent, and co-surfactant are C 16 TAB and C 18 It has been found that this process can influence the mesopore size distribution in mesoporous Y synthesis using TAB as a template. This process expands the pore size of mesoporous Y-type zeolite beyond what was previously achievable. Surfactants with longer alkyl chain lengths produced slightly larger mesopore sizes, while the addition of swelling agents further expanded the mesopore size, with TMB showing a stronger mesopore size expansion effect than p-xylene. TMB / C 18 Samples synthesized with a TAB ratio of 12 had a maximum mesopore size of 6.8 nm and 0.41 cm². 3 The mesopore volume was shown in units of / g. The addition of cosolvents could also alter the mesopore size, and TBA generally showed a stronger effect on mesopore expansion compared to ethanol, but the effect of cosolvent addition was TMB / C n This became less pronounced as the TAB ratio increased.

[0035] This process involves combining CTAB with a Y-type zeolite, a swelling agent, and a sodium hydroxide solution. The mixture is heated and stirred. Once the reaction is complete and the solid has precipitated, the mixture is cooled and the solid is filtered. The solid may be washed with water to achieve a neutral pH. The filtered solid may then be dried and calcined. In one embodiment, the swelling agent is TMB or paraxylene, with TMB being the preferred swelling agent. In one embodiment, CTAB is C 16 TAB or C 18 It is either TAB or C 18It has been found that the combination of TAB and the swelling agent TMB is extremely advantageous. In one embodiment, the Y-type zeolite is CBV270.

[0036] In another embodiment, the process first involves combining a sodium hydroxide solution with CTAB and a swelling agent. The resulting mixture is then heated as described above. Heating may be continued for 20 to 40 minutes at a temperature in the range of 85 to 95°C, after which Y-type zeolite is added to the mixture and the mixture is stirred until the reaction is complete. In one embodiment, as described above, CTAB is C 16 TAB or C 18 It is either TAB. In one embodiment, the swelling agent is TMB or paraxylene. Also, as mentioned above, in one embodiment, the Y-type zeolite is CBV270.

[0037] The reaction mixture is stirred for 4 to 7 hours. In one embodiment, stirring continues for about 6 hours. After the reaction is complete and the solid has settled, the mixture is usually cooled to room temperature or can be cooled. The settled solid is then filtered. In one embodiment, the solid is washed several times with water until the filtrate has a neutral pH. The neutral pH can be detected by pH test paper.

[0038] The filtered solid, whether washed or not, is then calcined. Calcination can typically be carried out at temperatures in the range of 550–650°C. In one embodiment, the temperature is approximately 580°C. Calcination can generally be carried out for several hours, for example, 4–7 hours. In one embodiment, calcination is carried out for approximately 5 hours. Calcination is also carried out in dry air in one embodiment. The mesopores of Y-type zeolite are, on average, considerably larger than those of the original or parent Y-type zeolite.

[0039] In this process, CTAB can be any suitable CTAB. In one embodiment, CTAB is C 16 TAB or C 18TAB. Longer alkyl chains in CTAB surfactants generally provide enlarged mesopores. In one embodiment, C 18 TAB is used in this process.

[0040] The swelling agents are generally TMB or paraxylene. Both have been found to improve and enlarge the size of mesopores when combined with CTAB. In one embodiment, TMB is used as the swelling agent. 18 It has been found that using TMB in combination with TAB is extremely advantageous and successful in dilating mesopores. 18 This is especially true when the molar ratio with TAB is approximately 12.

[0041] The molar ratio of TMB or paraxylene swelling agent to CTAB surfactant is generally in the range of 4 to 12. In one embodiment, the molar ratio is about 6, and in another embodiment, it is about 12.

[0042] In one embodiment, an alcohol cosolvent is also used in conjunction with the swelling agent. The alcohol cosolvent may be present in the initial mixture of CTAB, Y-type zeolite, swelling agent, and sodium hydroxide solution. If the Y-type zeolite is added after the initial mixture containing the aqueous sodium hydroxide solution, CTAB, and swelling agent has been formed, the cosolvent may be added after the Y-type zeolite has been added.

[0043] In this embodiment, the initial mixture is heated for 20–40 minutes, for example, about 25 minutes, after which the Y-type zeolite is added to the mixture while stirring. Subsequently, the co-solvent may be added 20–40 minutes after the addition of the Y-type zeolite, for example, about 30 minutes. This latter process has been found to work very well when using a co-solvent.

[0044] The alcohol cosolvent can be any suitable cosolvent. In one embodiment, the alcohol cosolvent may be ethanol or TBA. The alcohol solvent is preferably an alcohol with a larger molecular weight, such as TBA. When an alcohol with a larger molecular weight, such as TBA, is used, improved mesopore expansion is achieved.

[0045] The Y-type zeolite can be any suitable Y-type zeolite. Generally, Y-type zeolites contain mesopores from the outset. CBV720 is such a Y-type zeolite. This process works particularly well with CBV720.

[0046] In one embodiment, a nonionic surfactant may be used in combination with a CTAB surfactant. It has been found that using a nonionic surfactant together with a CTAB surfactant and a TMB swelling agent can provide advantageous results.

[0047] The following examples are provided to further illustrate the process and Y-type materials having larger mesopores. However, these examples are not intended to be limiting.

[0048] material The water used in all experiments was deionized water. The chemical used in the experiments was hexadecyltrimethylammonium bromide (C 16 TAB (manufactured by Sigma-Aldrich), trimethyloctadecylammonium bromide (C 18TAB (manufactured by Sigma-Aldrich), sodium hydroxide (pellets, Neta (Manufactured by Scientific), parent Y-type zeolite CBV720 (ZE0290, Si / Al=15, manufactured by Zeolyst), 1,3,5-trimethylbenzene (TMB, manufactured by Sigma-Aldrich), paraxylene (p-xylene, manufactured by Sigma-Aldrich), 1,4-diisopropylbenzene (DIPB, manufactured by Sigma-Aldrich), ethanol (manufactured by Sigma-Aldrich), tert-butanol (TBA, manufactured by Sigma-Aldrich), ammonium nitrate (NH4NO3, manufactured by Sigma-Aldrich, ≥99.5%), 2-methoxynaphthalene (2-MN, manufactured by Sigma-Aldrich, 99%), acetic anhydride (Ac2O, manufactured by Sigma-Aldrich, 99.5%), 1,2-dichloroethane (DCE, manufactured by Sigma-Aldrich, 99.8%), 1-acetyl-2-methoxynaphthalene (1,2-AMN, TCI) The chemicals used were Chemicals (>98.0%) and 2-acetyl-6-methoxynaphthalene (2,6-AMN, Sigma-Aldrich, 98.0%). All chemicals except Ac2O and DCE (Ac2O and DCE were dried with P2O5 / K2CO3 and CaH2, respectively, and then stored under an N2 atmosphere) were used without further purification.

[0049] C n Synthesis of mesoporous Y using TAB (n=16 and 18) as a surfactant The conventional surfactant-based mesoporous Y-type zeolite was synthesized using the procedure described below, which is a modification of an established procedure in the literature. Instead of adding all reagents to the plastic container before heating, as described in the literature, the parent zeolite CBV720 was introduced after the entire solution had reached the set temperature. Therefore, 0.5 g of hexadecyltrimethylammonium bromide (C) 16TAB and 20 mL of NaOH solution (0.16 M (NaOH / SiO2 ratio 0.19) unless otherwise specified, which falls within the NaOH / SiO2 range that generates amorphous walls via zeolite dissolution) were added to a plastic container and heated in a 90°C oil bath for 25 minutes. Then, 1.0 g of parent zeolite CBV720 was added to the solution. The molar composition of the mixture was 1.00 SiO2:0.192 Na:0.082 C n TAB(n=16 and 18): 66.7 H2O, and this mixture was stirred for 6 hours. After cooling, the contents were poured onto filter paper, and the precipitated solid was washed several times with water until the filtrate was neutral as measured with pH test paper. The samples were then dried overnight at 60°C and calcined in dry air at 580°C for 5 hours.

[0050] C n Synthesis of mesoporous Y using TAB and a swelling agent The synthesis method for preparing mesoporous Y-type zeolite using a swelling agent was similar to the procedure for mesoporous Y using the above-mentioned surfactant as a template, but as shown in Scheme 1 below, C 16 TAB or C 18 The difference was that various amounts of swelling agents (1,3,5-trimethylbenzene (TMB); paraxylene (p-xylene); DIPB) were added after TAB. In a typical synthesis, 0.5 g of C 16 TAB, 1.0 g of TMB (0.87 g of p-xylene; 1.35 g of DIPB), and 20 mL of NaOH solution (0.16 M) were added to a plastic bottle and heated in a 90°C oil bath for 25 minutes. Then, 1.00 g of CBV720 zeolite was added to the solution. The molar composition of the resulting mixture was 1.0SiO2:0.19Na:0.082C nThe ratio of TAB (n=16 and 18) was 0.49, and the ratio of swelling agent was 66.7H2O. When a cosolvent was used, either ethanol or TBA was added to the solution 30 minutes after the addition of the parent zeolite CBV720, and the molar ratio of the cosolvent to CnTAB (n=16 and 18) was 14.6:1. This mixture was stirred for 6 hours. After cooling, the contents were filtered, and the solid was washed several times with water until the filtrate was measured as neutral on pH test paper. The samples were then dried overnight at 60°C and calcined in dry air at 580°C for 5 hours.

[0051] The obtained sample was C n The formula is specified as TAB(n=16 and 18) + x swelling agent (+14.6 cosolvent), where x is the swelling agent / C n This is the molar ratio of TAB. The proton-type material was obtained by ion exchange at 60°C for 24 hours using a 1M NH4NO3 aqueous solution (liquid to zeolite weight ratio 50:1), after which the same washing and drying procedure described above was performed. This ion exchange procedure was repeated two more times before firing, following the same procedure described above. [ka]

[0052] Post-synthesis approaches for synthesizing mesoporous Y-type materials C as a surfactant 16 0.5 g of synthesized mesoporous Y-type material prepared using TAB is compared with 4.04 g of TMB (TMB vs. C 16 A suspension was prepared by mixing TAB (molar ratio 70), and the suspension was transferred to an autoclave with a Teflon® liner and heated at 160°C for 16 hours. After cooling, the contents were washed several times with either water or a mixture of water and ethanol, followed by drying and calcination. The resulting sample was C 16 TAB+70TMB post-compositing and C 16 It was designated as TAB+70TMB post-synthesis (water and ethanol).

[0053] Material property evaluation N2 physicoadsorption isotherms were measured at 77K using a Micromeritics ASAP2020 adsorption system. Before sample analysis, the samples were degassed under vacuum at 350°C for 4 hours to remove residues. Total specific surface area was calculated using the Brunauer-Emmett-Teller (BET) formula. Micropore volume, micropore surface area, and external surface area were measured using the t-plot method. Mesopore volume was calculated from adsorption branches using the Barrett-Joyner-Halenda (BJH) method. X-ray diffraction (XRD) patterns were collected using Cu Kα radiation (40kV, 15mA) with a step size of 0.01° in the range of 5° to 50° using a Rigaku MiniFlex X-ray diffractometer. SEM was performed using a Zeiss Crossbeam 550 scanning electron microscope with an operating voltage of 1kV and a working distance of 5.0mm.

[0054] Friedel-Crafts acylation reaction of 2-methoxynaphthalene (2-MN) The Friedel-Crafts acylation of 2-methoxynaphthalene (2-MN) using acetic anhydride (Ac2O) as the acyling agent (FCA Friedel-Crafts acylation) was performed to evaluate the accessibility of the catalytic active site of the synthesized material. Immediately after preparation, the zeolite was calcined in a tubular furnace and transferred to an argon-filled glove box in a moisture-free state for reaction preparation. Solid 2-MN was also introduced into the argon-filled glove box for reaction preparation. In a typical experiment, 100 mg of the selected material and 1.1 mmol of 2-MN were loaded into separate Schlenk tubes and sealed to maintain a moisture-free environment. The tubes were placed under a nitrogen atmosphere, and 10 mL of dry DCE, 0.31 mL of Ac2O (approximately 3.3 mmol), and 250 μL of dodecane (as an internal standard) were injected into the tubes containing the organic solids using a syringe in an air-free manner. The molar ratio of 2-MN to Ac2O was 1:3. Next, the tubes containing the catalyst and reagents were heated at a reaction temperature of 40°C for 15 minutes before introducing the reagent solution to the heated catalyst, which had been reacted for 10 minutes via cannula transfer. After the reaction was complete, the solution was filtered by syringe through a 0.2 μm PTFE filter and analyzed using an Agilent 6890 GC system equipped with a flame ionization detector (FID) and an HP-1 column (50 m × 0.32 mm × 1.05 μm). In all reactions, both the carbon balance and molar balance reached nearly perfect balances, with measured values ​​of over 90% and over 95%, respectively. The main product produced was 1-acetyl-2-methoxynaphthalene (1,2-AMN), which showed a selectivity of over 97% in all experiments.

[0055] Results, Discussion, and Conclusion C 16 Effects of TAB surfactants and swelling agents Conventional C 16Mesoporous Y, using TAB as a template, exhibits 3.5 nm mesopores, which are not present in the parent CBV720 zeolite. This mesopore size is comparable to that of related mesoporous Y-type materials reported in the literature. Compared to the parent CBV720 zeolite, conventional C 16 The total mesopore volume of mesoporous Y using TAB as a template is 2.5 times higher. When mesoporous Y is synthesized with a high concentration of 0.2 M NaOH instead of 0.16 M NaOH, (i) the mesopore size remains almost unchanged, and (ii) the mesopore volume increases (from 0.59 to 0.67 cm³). 3 (i) - This is a previously observed trend - and (iii) a slightly reduced recovery yield is observed. This suggests that high base concentrations do not enlarge the mesopore size of conventional mesoporous Y.

[0056] In the synthesis of mesoporous Y, p-xylene and TMB are used as swelling agents along with C 16 The results using TAB are shown in Figures 1A to 1F. TMB / C 16 As the TAB ratio increases from 0 to 12, the maximum mesopore size increases from 3.5 nm to 6.0 nm, and TMB / C 16 Further increasing the TAB in the range of 12 to 24 leads to a plateau in mesopore size (Figures 1B and 1C). The presence of this plateau when TMB is used as a swelling agent is common to previously reported MTS synthesis, although in the latter system the plateau is lower at TMB / C 16 This occurred at a TAB ratio of 5. In both cases, the plateau is thought to be caused by the saturation capacity of the surfactant aggregate for TMB uptake. Based on this premise, it is surprisingly clear that, compared to reported MTS synthesis, the surfactant aggregate and their associated capacity for TMB uptake are enhanced in this mesoporous Y synthesis.

[0057] When using p-xylene as a swelling agent in this synthesis, the p-xylene / C 16As the TAB ratio increases from 0 to 20, the maximum mesopore size increases from 3.5 nm to 5.4 nm (Figures 1E and 1F). The smaller size of p-xylene relative to TMB appears to result in a lower swelling effect, and therefore more p-xylene must be used to compensate for this in order to achieve the same mesopore size (i.e., a similar maximum mesopore size is achieved when p-xylene / C 16 TAB ratio 12 (5.1nm) and TMB / C 16 The result was obtained at a TAB ratio of 6 (5.0 nm). (See Table 1 below). However, the maximum pore size ultimately achievable was greater when using TMB as the swelling agent in this system than when using p-xylene, which again highlights the clear and important role of the former's greater steric bulk.

[0058] As shown in Table 1, the conventional C 16 Compared to mesoporous Y using TAB as a template, samples containing TMB or p-xylene showed a decrease in mesopore volume and an increase in micropore volume. In this comparison, the decrease in the former outweighed the increase in the latter, resulting in an overall decrease in total pore volume when synthesizing mesoporous Y without the use of a swelling agent. This result is in contrast to MTS material synthesis in the literature, where the addition of a swelling agent increased both mesopore size and total pore volume. Such contrasting results between these two systems are thought to be due to different pore shapes.

[0059] In summary, TMB / C 16 Using a TAB ratio of 12, a mesoporous Y-type material with mesopore size concentrated at 6.0 nm was synthesized. This sample was synthesized using the swelling agent shown in Table 1. 16 Among the samples using TAB as a template, 0.49 cm 3 It exhibited the highest mesopore volume at / g. The addition of a swelling agent controlled the mesopore volume and increased the mesopore size. [Table 1]

[0060] C as a surfactant 16 The PXRD patterns of samples synthesized using TAB with TMB or p-xylene as a swelling agent were found to be C at a higher NaOH concentration of 0.2M instead of 0.16M for the parent CBV720 zeolite. 16 The samples, including those synthesized using TAB, exhibit characteristic peaks of FAU zeolite at 2θ = 6.16, 10.13, 15.69, and 23.82, among others. Based on these data, it can be qualitatively concluded that all samples showed a degree of crystallinity comparable to that of the parent CBV720 zeolite. This conclusion is also supported by quantitative crystallinity studies in the literature, which show that the decrease in crystallinity in mesoporous Y is slight compared to the precursor material.

[0061] Furthermore, DIPB is DIPB / C 16 When applied as a swelling agent with a TAB ratio of 12, no evidence of larger or additional mesopore synthesis was observed compared to the parent CBV720 zeolite. The high hydrophobicity of DIPB appears to be the reason why incorporation of DIPB into the surfactant aggregate did not occur, which is due to the competitive adsorption of DIPB into the bulk of zeolite Y. Such results suggest an optimal hydrophobicity for the swelling agent, which is well represented by TMB, which has a larger stereobulb of alkyl substituents in TMB compared to p-xylene, but not as large as in DIPB, so that adsorption into the internal pores of the zeolite does not become dominant over incorporation into the mesoporous surfactant aggregate. Therefore, in one embodiment, TMB is used as a swelling agent with great advantage.

[0062] Effect of ethanol or tert-butanol (TBA tert-butyl alcohol) as a cosolvent Based on the best results obtained using TMB as the swelling agent described above, TMB was combined with a cosolvent consisting of ethanol or TBA to attempt to further increase the mesopore size in a surfactant-templated mesoporous Y-type material. The addition of ethanol was performed in the TMB / C 16 At a TAB ratio of 6, the mesopore size did not change (5.0 nm with and without ethanol addition), and TMB / C 16 At a TAB ratio of 12, the mesopore size was reduced (from 6.0 nm to 5.4 nm, Figures 1B and 2B). When TBA was added as a cosolvent, the TMB / C ratio was reduced. 16 At a TAB ratio of 6, the mesopore size increased from 5.0 nm to 5.4 nm, and TMB / C 16 The TAB ratio increased from 6.0 nm to 6.4 nm at 12 (Figures 1B and 2E). In summary, the addition of ethanol increased the TMB / C 16 The TAB ratio does not contribute at 6, and TMB / C 16 At a TAB ratio of 12, the mesopore size is reduced by 10.0% (from 6.0 nm to 5.4 nm). The addition of TBA is TMB / C 16 At TAB ratios of 6 and 12, the mesopore size was increased by 8.0% and 6.7% (from 5.0 nm to 5.4 nm and from 6.0 nm to 6.4 nm), respectively. Figures 2C and 2F show the effects of these cosolvents using parity plots.

[0063] The addition of a cosolvent can control the solubility of the swelling agent within the surfactant aggregate. Adding ethanol increases the solubility of TMB in the solution (i.e., outside the micelle core), resulting in less TMB uptake into the surfactant aggregate and the formation of smaller mesopores. This phenomenon leads to a higher TMB / C ratio, as shown in Figure 2C. 16This is more pronounced in the TAB ratio. However, TBA is less soluble than ethanol in water and is therefore less efficient at increasing the solubility of TMB in the solvent. Furthermore, compared to ethanol, the molecular size of TBA is large enough to increase the mesopore size when swelling the surfactant aggregate. This is as shown in Figures 2B and 2E, as shown in 1C 16 The mesopore size obtained when using the TAB+6TMB+14.6TBA composition was 1C 16 This was confirmed by the fact that the mesopore size was the same as that obtained when using the TAB + 12TMB + 14.6 ethanol composition. As a result, unlike with ethanol (Figure 2C), the addition of TBA showed a positive effect on the mesopore size, as shown in Figure 2F. Therefore, in one embodiment, TBA can be used as a cosolvent with great advantage.

[0064] Both cosolvents investigated (ethanol and TBA) compared to materials without cosolvents in Table 1 showed TMB / C 16 At a TAB ratio of 6, an increase in mesopore volume occurs, and TMB / C 16 A decrease occurred at a TAB ratio of 12. The best results were observed when TBA was added at a TMB / C16TAB ratio of 6, in which case the results were 0.38 cm³ compared to the control without TBA. 3 Compared to / g, the mesopore volume is up to 0.51 cm³. 3 The amount was increased to / g. The data in Table 2 (compared to the control in Table 1) also shows a slightly higher recovery yield when the co-solvent is added. According to PXRD, the crystallinity of the samples prepared using TBA and ethanol co-solvents showed similar characteristic peak intensities corresponding to FAU zeolite compared to the control material synthesized without the use of a co-solvent. [Table 2]

[0065] C 18 Effects of TAB surfactants and swelling agents A three-dimensional, bulkier C18 When using the TAB surfactant, the synthesis using only the surfactant (NaOH / SiO2 ratio 0.19; 16 hours at 90 °C) resulted in a mesopore size of 4.3 nm, as shown in Figure 3B. C 18 When the TAB surfactant was used under slightly different conditions (NaOH / SiO2 ratio 0.2; 20 hours at 115 °C), a pore size of 4.1 nm was obtained. C 18 Under another synthesis condition using the TAB surfactant (NaOH / SiO2 ratio 0.10; 2 minutes at 210 °C), a slightly larger mesopore size of 4.7 nm was obtained. C 16 Compared with the result using the TAB surfactant (mesopore size of 3.5 nm), when the alkyl chain length of the surfactant was increased from C 16 TAB to C 18 TAB, it was generally observed that the mesopore size increased. This is consistent with previous results indicating that in the synthesis of mesoporous Y zeolite, the mesopore size is directly correlated with the alkyl chain length of the surfactant. When the alkalinity of the NaOH solution used in the synthesis (0.2M NaOH; NaOH / SiO2 ratio 0.24) was increased, a synthesis with a decreased mesopore size of 3.5 nm in the distribution was observed, and a mesopore volume of 0.72 cm 3 / g, slightly higher compared to 0.60 cm 3 / g, was observed. These trends are consistent with previous results when using C 18 TAB to template mesoporosity in the synthesis of Y zeolite.

[0066] The effect of the carbon length of the surfactant alkyl chain on the mesopore size when using TMB as the swelling agent (C 16 TAB and C 18 TAB) is shown in Figure 3C. Except for the higher mesopore size described above, the material templated with C 18 TAB showed almost the same textural properties as the material synthesized using C 16 TAB, as shown in Table 1. C 18 The samples synthesized using C 16It shows a larger mesopore size compared to those using TAB.

[0067] When TMB was added, the mesopore volume of the sample decreased as shown in Table 3. This is because C 16 This is the same trend observed in systems using TAB as a template. However, C 16 TMB / C in the TAB system 16 TAB ratio 12 (0.49 cm in Table 1) 3 Compared to / g, C 18 TMB / C in the TAB system 18 At a TAB ratio of 6, a larger mesopore volume (0.51 cm³ in Table 3) is observed. 3 / g) was observed. 18 In a system using TAB as a template, the effect of TMB as a swelling agent corresponds to C 16 This appears to be more pronounced than in systems using TAB as a template. Furthermore, comparable recovery yields were observed even when different surfactants were used, as shown in the data in Tables 1 and 3. Notably, TMB / C 18 At a TAB ratio of 12, a mesoporous Y-type material with a mesopore size of 6.8 nm was synthesized, which was the largest mesopore size among all materials investigated. 18 The application of TAB is C 16 It appears that the mesopore size can be increased compared to what is achievable with TAB, and that the mesopore size can be further increased by using TMB as a swelling agent. [Table 3]

[0068] C 18 The PXRD patterns of samples synthesized using the TAB template system show similar relative crystallinity to the parent CBV720 zeolite. This trend is observed even at higher crystallization temperatures. 18 This is consistent with literature findings on mesoporous Y synthesis using TAB as a template. Other researchers have previously found that C 18When synthesizing mesoporous Y using TAB surfactant, a significant decrease in crystallinity was observed compared to CBV720. Details of the synthesis conditions other than the surfactant used may be the cause of the different crystallinity results.

[0069] C 18 The effect of cosolvents in TAB-oriented synthesis The data in Figures 4A-4C is TMB / C 18 The addition of ethanol at a TAB ratio of 6 results in a mesopore size of 6.0 nm, which is larger than the 5.1 nm size corresponding to the control sample synthesized without ethanol, as shown in Figures 3A-3D. Such results indicate that C, where no expansion of mesopore size was observed with the addition of ethanol, is not a significant improvement. 16 The data is qualitatively different from that obtained from TAB-directed synthesis.

[0070] When TBA is added, TMB / C 18 C synthesized with a TAB ratio of 6 18 The sample using TAB as a template yielded a mesopore size of 6.2 nm, which is slightly higher than the material obtained by adding ethanol as described above. Figure 4C shows that the addition of a cosolvent results in TMB / C 18 At a TAB ratio of 6, it is shown that the mesopore size increases by 21.6% (1.1 nm; TBA as cosolvent) and 17.6% (0.9 nm; ethanol as cosolvent). However, TMB / C 18 When the TAB ratio was increased to 12, a bimodal mesopore size distribution was obtained at 6.8 nm and 8.6 nm, respectively, after TBA addition (see Figure 4B). The same mesopore size distribution was obtained with TMB / C 18 It was also obtained when the TAB ratio was 12 and TBA was absent (i.e., sample 1C in Figure 3B). 18 TAB + 12TMB). The addition of TBA is TMB / C 18 It has been concluded that a TAB ratio of 12 contributes little to mesopore dilation.

[0071] As shown in Table 4 below, C 18At a TAB / TMB ratio of 6, the addition of cosolvents (both ethanol and TBA) reduces the mesopore volume compared to the results in Table 3 when no cosolvents are present. 18 At a TAB / TMB ratio of 12, the mesopore size distribution did not change, but the addition of TBA also reduced the mesopore volume compared to the control group without TBA (Table 3). The recovery yield was similar to that of the synthesis without these cosolvents. The corresponding PXRD patterns showed similar relative crystallinity to the control group without cosolvents, which is C 16 This is consistent with the results obtained in systems using TAB as a template. [Table 4]

[0072] The swelling agent, co-solvent, and co-surfactant are C 16 TAB and C 18 In the synthesis of mesoporous Y using TAB as a template, it was found that it could affect the mesopore size distribution. Surfactants with longer alkyl chain lengths produced slightly larger mesopore sizes, but the addition of swelling agents further expanded the mesopore size, and TMB showed a stronger mesopore size expansion effect than p-xylene. TMB / C 18 Samples synthesized with a TAB ratio of 12 exhibited a maximum mesopore size of 6.8 nm and a mesopore volume of 0.41 cm³. 3 The ratio was / g. The addition of a cosolvent could also change the mesopore size, and TBA generally showed a stronger effect on mesopore expansion compared to ethanol, but the effect of cosolvent addition was TMB / C n This became less pronounced as the TAB ratio increased.

[0073] The acidic site catalyst accessibility in the mesoporous Y-type zeolite with the largest pore size obtained was demonstrated in the acylation of 2-MN using acetic anhydride (Ac2O) as a probe reaction. The data in Table 5 are C 18 TAB was used as a template (pore size 4.3 nm) and C 18Both TAB+12TMB templates (pore size 6.8 nm) showed high selectivity to 1,2-AMN, which is consistent with literature data, whereas the literature used much higher reaction temperatures (100°C and 150°C) than the methods of the present invention, whereas the processes of the present invention use temperatures below 50°C, 20-50°C, and 40°C in one embodiment. Similar conversion rates (18.3%-20.0%) were observed for both materials, suggesting that the supramolecular approach of the present invention maintains the integrity and accessibility of the acidic sites found in conventional mesoporous Y-type zeolites. This is consistent with the mild nature of the non-covalent interactions and organic additives used for mesopore expansion in the methods of the present invention. [Table 5]

[0074] C n Larger pores in mesoporous Y-type zeolites (n=16 and 18) using TAB as a template can be achieved via a non-covalent approach involving the addition of swelling agents and cosolvents during the current surfactant assembly and material synthesis process. TMB exhibits a stronger mesopore size-enhancing effect than both p-xylene and DIPB as a swelling agent, demonstrating optimal hydrophobicity as a swelling agent. TMB / C 18 Samples synthesized with a TAB ratio of 12 exhibited a maximum mesopore size of 6.8 nm and a mesopore volume of 0.41 cm³. 3 The ratio was / g, and it showed the same catalyst accessibility and rate as conventional mesoporous Y-type zeolites. Furthermore, the addition of a co-solvent could change the mesopore size, and TBA generally showed a stronger effect on mesopore expansion compared to ethanol, but the effect of co-solvent addition was TMB / C n The increase in the TAB ratio is not significant. The addition of swelling agents and cosolvents is [OH -The activity-reducing effect decreased the mesopore volume, but this can be compensated for by using higher NaOH concentrations, while maintaining the same enlarged mesopore size distribution brought about by the organic additive. When a large excess of TMB was reacted post-synthesis with conventional mesoporous Y-type material at high temperature, little change was observed in the maximum value of the pore size distribution, and only the synthesis of slightly larger mesopores in the range of 9.4–17.0 nm was observed. These results highlight the importance of adding organic additives during mesoporous Y synthesis, where the surfactant aggregate is more prone to swelling.

[0075] Despite the efforts of the present invention, synthesizing mesoporous Y-type materials with mesopore sizes larger than 10 nm is difficult, and alternative routes for synthesizing such larger mesopores are needed in mesoporous Y-type zeolite materials.

[0076] As used in this disclosure, the term "comprises" or "comprising" is intended as an open-ended transition meaning that it includes the named elements, but does not necessarily exclude other unnamed elements. The phrase "consists essentially of" or "consists essentially of" is intended to mean that it excludes other elements that are of essential importance to the composition. The phrase "consisting of" or "consists of" is intended to mean a transition that excludes all elements other than those described, with the exception of trace impurities.

[0077] All patents and publications referenced herein are incorporated herein by reference to the extent that they do not conflict with the present invention. It is understood that certain of the specific structures, functions and operations described above in the embodiments described above are not necessarily required to carry out the present invention and are described merely for the sake of the exemplary embodiments or the completeness of the exemplary embodiments. Furthermore, it is understood that certain structures, functions and operations shown in the referenced patents and publications described above can be carried out in combination with the present invention, but are not essential to carrying out the present invention. Accordingly, it is understood that the present invention can be carried out in a manner different from that specifically described herein and will not actually depart from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A process for preparing a surfactant-templated mesoporous Y-type zeolite, comprising the following steps: (a) A step of combining a sodium hydroxide solution with CTAB and TMB or paraxylene (p-xylene), and heating the mixture. (b) A step of adding Y-type zeolite while stirring the heated mixture from (a), (c) A step of cooling the heated mixture and filtering out the solid, and (d) A step of drying and firing the filtered solid.

2. The process according to claim 1, wherein the mixture of (a) is heated for 20 to 30 minutes.

3. The process according to claim 2, wherein the mixture is heated to a temperature in the range of 85 to 95°C.

4. The process according to claim 2, wherein in (b), the Y-type zeolite is added after heating for 20 to 40 minutes.

5. The process according to claim 1, wherein the stirring in (b) is continued for 4 to 7 hours.

6. The process according to claim 5, wherein the stirring in (b) is continued for about 6 hours.

7. The process according to claim 1, wherein after filtering the solid in (c), the filtered solid is washed with water.

8. The process according to claim 7, wherein the washing of the solid is continued until the filtrate has a neutral pH.

9. The process according to claim 1, wherein the firing in (d) is carried out at a temperature in the range of 550 to 650°C.

10. The process according to claim 9, wherein the firing is carried out in dry air.

11. The process according to claim 1, wherein TMB is added.

12. The process according to claim 11, wherein the molar ratio of TMB / CTAB is in the range of 4 to 12.

13. The process according to claim 12, wherein the molar ratio is approximately 6.

14. The process according to claim 12, wherein the molar ratio is approximately 12.

15. The aforementioned CTAB is C １６ The process according to claim 11, wherein it is TAB.

16. The aforementioned CTAB is C １８ The process according to claim 11, wherein it is TAB.

17. The process according to claim 11, wherein after the CBV720 zeolite is added, an alcohol is added to the mixture being stirred in (b).

18. The process according to claim 11, wherein the alcohol is added 20 to 40 minutes after the CBV720 zeolite has been added.

19. The process according to claim 17, wherein the alcohol is TBA or ethanol.

20. The process according to claim 19, wherein the alcohol is TBA.

21. The process according to claim 16, wherein TBA is added to the mixture being stirred in (b) after the CBV270 zeolite has been added.

22. The process according to claim 11, further comprising adding a nonionic surfactant to the mixture of (a).

23. The aforementioned CTAB is C １６ The process according to claim 21, wherein it is TAB.

24. The process according to claim 1, wherein p-xylene is added.

25. The process according to claim 24, wherein the molar ratio of p-xylene / CTAB is in the range of 4 to 12.

26. The process according to claim 25, wherein the molar ratio is approximately 6.

27. The process according to claim 25, wherein the molar ratio is approximately 12.

28. The aforementioned CTAB is C １６ The process according to claim 24, wherein it is TAB.

29. The aforementioned CTAB is C １８ The process according to claim 24, wherein it is TAB.

30. The process according to claim 24, wherein after the CBV720 zeolite is added, an alcohol is added to the mixture being stirred in (b).

31. The process according to claim 24, wherein the alcohol is added 20 to 40 minutes after the CBV720 zeolite has been added.

32. The process according to claim 30, wherein the alcohol is p-xylene or ethanol.

33. The process according to claim 32, wherein the alcohol is p-xylene.

34. The process according to claim 29, wherein TBA is added to the mixture being stirred in (b) after the CBV270 zeolite has been added.

35. The process according to claim 1, wherein the Y-type zeolite in (b) is CBV720.

36. A process for preparing a mesoporous Y-type zeolite using a surfactant as a template, comprising the following steps: (a) Sodium hydroxide solution C １８ A step of heating the mixture with TAB and TMB for 20 to 40 minutes. (b) Adding Y-type zeolite to the heated mixture of (a) while stirring, and continuing stirring for 4 to 7 hours. (c) A step of cooling the mixture, filtering the solid, and washing the filtered solid with water, (d) A step of drying and firing the solid from (c).

37. The process according to claim 36, wherein the molar ratio of TMB / C18TAB is in the range of 4 to 12.

38. The process according to claim 37, wherein the molar ratio is approximately 12.

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