Modified zeolites including amine functional groups and methods of making same

Abstract

A modified zeolite may include a microporous framework comprising a plurality of micropores having a diameter of less than or equal to 2 nm, where the microporous framework comprises at least silicon atoms and oxygen atoms; the diameter of the mesopores is larger than 2 nm and smaller than or equal to 50 nm, and the mesopores are orderly arranged in a cubic symmetry mode. The modified zeolite further includes: an isolated terminal primary amine functional group bonded to a silicon atom of the microporous framework; or a silazane functional group, wherein a nitrogen atom of the silazane bridges two silicon atoms of the microporous backbone; or both.

Description

Cross-references to related applications

[0001] This application claims the benefit of U.S. non-provisional application series number 18 / 470,076, filed on September 19, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure generally relates to porous materials, and more specifically to zeolites. Background Technology

[0003] Porous materials, such as zeolites, are used in many petrochemical industry applications. For example, such materials can be used as catalysts in a variety of reactions that convert hydrocarbons or other reactants in feedstock chemicals into product chemicals. Zeolites can be characterized by their microporous framework type. Various types of zeolites have been identified over the past few decades, with zeolite type typically described by framework type, while specific zeolite materials can be more specifically identified by various names such as ZSM-5, β (Beta), or USY. Summary of the Invention

[0004] This disclosure relates to modified zeolites comprising amine functional groups and a plurality of mesopores arranged in an ordered cubic symmetry. In some embodiments, the modified zeolite may include primary and / or secondary amine functionalization. Specifically, the modified zeolite may include one or both of the following: isolated terminal primary amine functional groups bonded to silicon atoms in the microporous framework, or silazane functional groups, wherein the nitrogen atom of the silazane bridges two silicon atoms in the microporous framework. According to one or more embodiments of this disclosure, such modified zeolites may have enhanced or differentiated catalytic properties compared to conventional zeolites.

[0005] According to one or more embodiments of this disclosure, the modified zeolite comprises: a microporous framework comprising a plurality of micropores with a diameter less than or equal to 2 nm, wherein the microporous framework comprises at least silicon atoms and oxygen atoms; and a plurality of mesopores with a diameter greater than 2 nm and less than or equal to 50 nm, wherein the plurality of mesopores are arranged in a cubic symmetry order. The modified zeolite further comprises: an isolated terminal primary amine functional group bonded to silicon atoms of the microporous framework; or a silazane functional group, wherein the nitrogen atom of the silazane bridges two silicon atoms of the microporous framework; or both.

[0006] According to one or more embodiments of this disclosure, a method for processing a hydrocarbon feedstock includes: contacting the hydrocarbon feedstock with a modified zeolite to form a product, wherein the modified zeolite comprises: a microporous framework containing a plurality of micropores with a diameter less than or equal to 2 nm, wherein the microporous framework contains at least silicon atoms and oxygen atoms; and a plurality of mesopores with a diameter greater than 2 nm and less than or equal to 50 nm, wherein the plurality of mesopores are arranged in a cubic symmetry order. The modified zeolite comprises: isolated terminal primary amine functional groups bonded to silicon atoms of the microporous framework; or silazane functional groups, wherein the nitrogen atom of the silazane bridges two silicon atoms of the microporous framework; or both.

[0007] According to one or more embodiments of this disclosure, a method for preparing modified zeolite includes: contacting a dehydroxylated zeolite with ammonia, wherein the dehydroxylated zeolite comprises: a microporous framework containing a plurality of micropores with a diameter less than or equal to 2 nm, wherein the microporous framework contains at least silicon atoms and oxygen atoms; a plurality of mesopores with a diameter greater than 2 nm and less than or equal to 50 nm, wherein the plurality of mesopores are arranged in a cubic symmetric order; and isolated terminal silanol functional groups containing hydroxyl groups bonded to silicon atoms of the microporous framework; wherein contacting the dehydroxylated zeolite with ammonia forms modified zeolite.

[0008] Additional features and advantages of the embodiments will be set forth in the following detailed description, and some of these features will be apparent to those skilled in the art from the description or by practice of the embodiments, including the following detailed description, the claims and the drawings.

[0009] Brief description of the attached figures The following detailed description of specific embodiments of this disclosure can be best understood when read in conjunction with the accompanying drawings, wherein the same structures are indicated by the same reference numerals, and wherein: Figure 1A A transmission electron microscope (TEM) image depicting a zeolite containing mesopores arranged in an ordered cubic symmetry according to Example 1 is shown. Figure 1B A TEM micrograph depicting the zeolite of Example 1 containing mesopores arranged in an ordered manner with cubic symmetry is shown. Figure 1C A schematic diagram of the FAU unit cell and its arrangement is depicted to provide a mesopore with cubic symmetry according to one or more embodiments described herein; Figure 2A A low-angle X-ray diffraction (XRD) pattern of the zeolite of Example 1 containing mesoporous structures with cubic symmetry was depicted. Figure 2B A high-angle XRD pattern of the zeolite of Example 1 containing mesopores arranged in an ordered cubic symmetry is depicted. Figure 3The Fourier transform infrared (FTIR) spectrum of the dehydroxylated zeolite of Example 2 is depicted; Figure 4 The dehydroxylated zeolite of Example 2 is described. 1 H-MAS-NMR spectrum; Figure 5 The dehydroxylated zeolite of Example 2 is described. 29 Si-CP-MAS-NMR spectrum; Figure 6 The dehydroxylated zeolite of Example 2 is described. 27 Al-MAS-NMR spectrum; Figure 7 The FT-IR spectrum of the modified zeolite of Example 3 was depicted; Figure 8 The modified zeolite of Example 3 is described. 1 H-MAS-NMR spectrum; Figure 9 The modified zeolite of Example 3 is described. 29 Si-CP-MAS-NMR spectrum; Figure 10 The modified zeolite of Example 3 is described. 27 Al-MAS-NMR spectrum; Figure 11 XRD patterns of the dehydroxylated zeolite of Example 2 and the modified zeolite of Example 3 are depicted. Figure 12 The N2 physisorption isotherms of the dehydroxylated zeolite of Example 2 and the modified zeolite of Example 3 were depicted. Figure 13 The pyridine FT-IR spectrum of the modified zeolite of Example 3 was depicted; Figure 14A TEM micrographs depicting the dehydroxylated zeolite of Example 2; Figure 14B TEM micrographs depicting the dehydroxylated zeolite of Example 2; Figure 15A TEM micrographs depicting the modified zeolite of Example 3; Figure 15B TEM micrographs of the modified zeolite of Example 3 are depicted.

[0010] Various embodiments of this disclosure will now be described in more detail, some of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used in all the drawings to refer to the same or similar parts. Detailed Implementation

[0011] This disclosure relates to zeolites modified by amine functional groups. As described herein, "modified zeolite" refers to a zeolite comprising amine functional groups. According to one or more embodiments, the amine functional groups may include isolated terminal primary amine functional groups and / or silazane functional groups as described herein.

[0012] According to the embodiments disclosed herein, modified zeolites can be prepared by a process including dehydroxylating an initial zeolite and forming a modified zeolite from the dehydroxylated zeolite. While embodiments of modified zeolites prepared by this process are disclosed herein, the embodiments disclosed herein should not be considered as limited to zeolites prepared by this process. Embodiments of zeolites modified with amine functional groups are depicted in chemical structure #1. For example, chemical structure #1 includes an isolated terminal primary amine functional group bonded to silicon atoms in a microporous framework, and a silazane functional group in which the nitrogen atom of the silazane bridges two silicon atoms in the microporous framework. In some embodiments, only one of these moiety may be present while the other is omitted.

[0013]

[0014] Chemical structure #1 To avoid being bound by theory, modified zeolites containing mesoporous structures with cubic symmetry and amine functional groups (e.g., isolated terminal primary amine functional groups and / or silazane functional groups) can exhibit enhanced or differentiated catalytic functions compared to conventional zeolites. Furthermore, to avoid being constrained by theory, the acidity of modified zeolites can be tuned by modifying them with amine functional groups, thereby adjusting their catalytic properties.

[0015] To avoid being bound by theory, the cubic ordering of mesopores allows them to interconnect throughout the modified zeolite, forming an interconnected, ordered mesoporous system. This interconnectedness facilitates the diffusion of large reactant molecules into the modified zeolite and their reaction. Furthermore, the cubic ordering of the mesopores imparts size and shape selectivity to the modified zeolite, as molecules of different sizes and shapes diffuse with varying efficiencies through the cubically ordered mesopores. Moreover, the cubic ordering of the mesopores enhances the accessibility of amine functional groups within the modified zeolite.

[0016] As described herein, “initial” zeolites can be provided or prepared as disclosed in this disclosure. According to one or more embodiments described herein, the initial zeolite comprises a plurality of mesopores arranged in an ordered cubic symmetry. As described herein, the characterization of the zeolite structure and material can be equally applied to the initial zeolite as well as dehydroxylated zeolites and / or modified zeolites. In one or more embodiments, the structure and material composition of the initial zeolite remain substantially unchanged during the dehydroxylation and / or amine functionalization steps (except for the introduction of the functional groups formed by the dehydroxylation and amine functionalization steps). For example, the framework type and general material composition of the framework in the initial and modified zeolites can be substantially the same, except for the addition of amine functional groups (e.g., isolated terminal primary amine functional groups and / or silazane functional groups). Similarly, the mesoporousness of the initial zeolite can be retained in the modified zeolite. Therefore, when “zeolite” is described herein in relation to its structural characterization, the description can refer to the initial zeolite, dehydroxylated zeolite, and / or modified zeolite.

[0017] As used throughout this disclosure, "zeolite" can refer to a microporous inorganic material having regular intracrystalline cavities and molecular-sized channels. Zeolites typically contain crystalline structures, rather than the amorphous structures observed in some porous materials (e.g., amorphous silica). Zeolites typically comprise a microporous framework identifiable by its framework type. The microporous structure of zeolites (e.g., pore sizes from 0.3 nm to 2 nm) provides a large surface area and desired size / shape selectivity, which may be advantageous for catalysis. The zeolite may comprise, for example, aluminosilicates, titanosilicates, or pure silicates. In embodiments, the zeolite may comprise micropores (present in the microstructure of the zeolite) and additionally mesopores. As used throughout this disclosure, a micropore refers to a pore in a structure with a diameter less than or equal to 2 nm and greater than or equal to 0.1 nm, and a mesopore refers to a pore in a structure with a diameter greater than 2 nm and less than or equal to 50 nm. Unless otherwise described herein, "pore size" of a material refers to the average pore size, but the material may additionally include mesopores with specific sizes inconsistent with the average pore size, thus encompassing a pore size distribution.

[0018] Typically, zeolites can be characterized by defining the framework type of their microporous structure. In one or more embodiments, the zeolites currently described are not particularly limited by framework type. Framework types are described, for example, in "Atlas of Zeolite Framework Types" by Ch. Baerlocher et al. (Fifth Revision, 2001), which is incorporated herein by reference.

[0019] According to one or more embodiments, the zeolite described herein may contain at least silicon and oxygen atoms. In some embodiments, the microporous framework may consist essentially only of silicon and oxygen atoms (e.g., a silica material). However, in other embodiments, the zeolite may include other atoms, such as aluminum. Such zeolites may be aluminosilicate zeolites. In further embodiments, the microporous framework may include titanium atoms, and such zeolites may be titanosilicate zeolites.

[0020] In one or more embodiments, the zeolite may comprise an aluminosilicate microstructure. The zeolite may comprise at least 99% by weight of a combination of silicon, oxygen, and aluminum atoms. The silicon / aluminum molar ratio may be from 1.5 to 10000. For example, but not limited to, the Si / Al molar ratio may be 1.5 to 10000, 1.5 to 5000, 1.5 to 2000, 1.5 to 1000, 1.5 to 800, 1.5 to 600, 1.5 to 400, 1.5 to 200, 1.5 to 100, 5 to 10000, 5 to 5000, 5 to 2000, 5 to 1000, 5 to 800, 5 to 600, 5 to 400, 5 to 200. 5 to 100, 10 to 10000, 10 to 5000, 10 to 2000, 10 to 1000, 10 to 800, 10 to 600, 10 to 400, 10 to 200, 10 to 100, 50 to 10000, 50 to 5000, 50 to 2000, 50 to 1000, 50 to 800, 50 to 600, 50 to 400, 50 to 200 or 50 to 100, or any combination of these ranges.

[0021] In the implementation scheme, the zeolite may comprise microstructures characterized by the following framework types, including micropores: BEA framework type zeolites (e.g., but not limited to Beta zeolite), FAU framework type zeolites (e.g., but not limited to Y zeolite or ultrastable Y zeolite), MOR framework type zeolites, MFI framework type zeolites (e.g., but not limited to ZSM-5 or Silicalite-1), CHA framework type zeolites (e.g., but not limited to chalcogenide), LTL framework type zeolites (e.g., but not limited to L zeolite), LTA framework zeolites (e.g., but not limited to A zeolite), AEI framework type zeolites, or MWW framework type zeolites (e.g., but not limited to MCM-22). It should be understood that... BEA, MFI, MOR, FAU, CHA, LTL, LTA, AEI, and MWW refer to the zeolite skeleton types identified by their respective three-letter codes established by the International Zeolite Association (IZA). Other skeleton types are considered in the embodiments of this disclosure.

[0022] In one or more embodiments, the zeolite may comprise a FAU framework type zeolite, such as Y zeolite or ultrastable Y zeolite (USY). As used herein, “Y zeolite” and “USY” refer to a zeolite having a FAU framework type according to the IZA zeolite nomenclature and consisting primarily of silica and alumina, as will be understood by those skilled in the art. In one or more embodiments, USY may be prepared from Y zeolite by steaming it at a temperature above 500°C. The molar ratio of silica to alumina may be at least 3. For example, the molar ratio of silica to alumina in Y zeolite may be at least 5, at least 12, at least 30, or even at least 200, such as 5 to 200, 12 to 200, or about 15 to about 200. The cell size of Y zeolite may be about 24 angstroms to about 25 angstroms, such as 24.56 angstroms.

[0023] In addition to the micropores typically defined for zeolite framework types, zeolites may also contain mesopores. As used herein, "mesoporous zeolite" refers to a zeolite containing mesopores, with an average mesopore diameter ranging from 2 nm to 50 nm. The mesoporous zeolites of this disclosure have an average mesopore diameter greater than 2 nm, for example, 4 nm to 16 nm, 6 nm to 14 nm, 8 nm to 12 nm, or 9 nm to 11 nm. In some embodiments, most of the mesopores may be greater than 8 nm, greater than 9 nm, or even greater than 10 nm. The mesopore size of the mesoporous zeolite can range from 2 nm to 40 nm, with a median pore size ranging from 4 nm to 12 nm. The mesoporous zeolite can typically be a silicon-containing material, such as aluminosilicates, pure silicates, or titanosilicates.

[0024] The mesoporous zeolites described in this disclosure may exhibit enhanced catalytic activity compared to non-mesoporous zeolites. Without being bound by theory, it is believed that the microporous structure imparts most of the catalytic functionality to the mesoporous zeolites. Mesopority may also allow for greater catalytic activity because more micropores are available for contact with reactants during the catalytic reaction. Mesopores generally allow for better access to microporous catalytic sites on the mesoporous zeolite, especially when reactant molecules are relatively large. For example, larger molecules can diffuse into the mesopores to contact additional microporous catalytic sites.

[0025] In one or more embodiments, the specific surface area of ​​the mesoporous zeolite can be 200 m² / g to 1500 m² / g, 400 m² / g to 1500 m² / g, 600 m² / g to 1500 m² / g, 800 m² / g to 1500 m² / g, 1000 m² / g to 1500 m² / g, 1200 m² / g to 1500 m² / g, 1400 m² / g to 1500 m² / g, 200 m² / g to 1300 m² / g, 200 m² / g to 1100 m² / g, 200 m² / g to 900 m² / g, 200 m² / g to 700 m² / g, 200 m² / g to 500 m² / g, 200 m² / g to 300 m² / g, or any combination of these ranges. In one or more embodiments, the pore volume of the mesoporous zeolite can be 0.01 cm³. 3 / g to 1.5 cm 3 / g, 0.05 cm 3 / g to 1.5 cm 3 / g, 0.1 cm 3 / g to 1.5 cm 3 / g, 0.3cm 3 / g to 1.5 cm 3 / g, 0.5 cm 3 / g to 1.5 cm 3 / g, 0.7 cm 3 / g to 1.5 cm 3 / g, 0.9 cm 3 / g to 1.5 cm 3 / g, 1.1 cm 3 / g to 1.5 cm 3 / g, 1.3 cm 3 / g to 1.5 cm 3 / g, 0.01 cm 3 / g to 1.4 cm 3 / g, 0.01 cm 3 / g to 1.2cm 3 / g, 0.01 cm 3 / g to 1.0 cm 3 / g, 0.01 cm 3 / g to 0.8 cm 3 / g, 0.01 cm 3 / g to 0.6 cm 3 / g, 0.01cm 3 / g to 0.4 cm 3 / g, 0.01 cm 3 / g to 0.2 cm 3 / g, 0.01 cm 3 / g to 0.1 cm 3 / g, 0.01 cm 3 / g to 0.05cm 3 / g or any combination of these endpoints. In a further embodiment, the specific surface area contributed by mesopores may account for greater than or equal to 20%, greater than or equal to 25%, greater than or equal to 30%, greater than or equal to 35%, greater than or equal to 40%, greater than or equal to 45%, greater than or equal to 50%, greater than or equal to 55%, greater than or equal to 60%, or even greater than or equal to 65%, for example, between 20% and 70%. In other embodiments, the pore volume contributed by mesopores may account for greater than or equal to 20%, greater than or equal to 30%, greater than or equal to 35%, greater than or equal to 40%, greater than or equal to 45%, greater than or equal to 50%, greater than or equal to 55%, greater than or equal to 60%, greater than or equal to 65%, greater than or equal to 70%, or even greater than or equal to 75%, for example, between 20% and 80%. Not wishing to be bound by theory, when mesopores dominate the total porosity of the modified zeolite, large reactant molecules can more easily diffuse into the modified zeolite and react. Specific surface area, average pore size, and pore volume distribution can be measured by an N2 adsorption isotherm at 77 Kelvin (K) (e.g., using a Micrometrics ASAP 2020 system). The Brunauer-Emmett-Teller (BET) analytical method can also be used, as those skilled in the art will understand.

[0026] In one or more embodiments, the mesoporous zeolite comprises a plurality of mesopores arranged in an ordered cubic symmetry. In one or more embodiments, the mesopores may be arranged in an ordered cubic symmetry with space groups Ia-3d, Fm-3m, Pm-3n, Pn-3m, Im-3m, or Fd-3m. As described herein, space groups describe combinations of 32 crystallographic point groups and 14 Bravais lattices, taking into account reflection symmetry, rotational symmetry, imperfect rotational symmetry, screw axial symmetry, and slip plane symmetry. A total of 230 space groups describe possible symmetries. In one or more embodiments, the mesoporous zeolite may comprise mesopores arranged in an ordered cubic symmetry with space group Ia-3d. In one or more embodiments, the mesoporous zeolite may comprise mesopores arranged in an ordered cubic symmetry with space group Fm-3m. In one or more embodiments, the mesoporous zeolite may comprise mesopores arranged in an ordered cubic symmetry with space group Fd-3m. Unwilling to be bound by theory, the cubically ordered arrangement of mesopores allows for improved diffusion of reactants into the active sites of the modified zeolite and improved diffusion of products away from the active sites. The cubic order of the mesopores leads to their interconnection throughout the modified zeolite, forming an interconnected, ordered mesoporous system. This interconnectedness allows larger reactant molecules to diffuse more easily into the modified zeolite and react. Furthermore, the cubic order of the mesopores imparts size and shape selectivity to the modified zeolite, as molecules of different sizes and shapes can diffuse with varying efficiencies through the cubically ordered mesopores of the modified zeolite. Moreover, the introduction of cubically ordered mesopores provides additional accessibility to organometallic groups, enabling grafting onto the zeolite at higher loading rates.

[0027] The presence of cubically symmetric ordered mesopores in mesoporous zeolites can be determined by the presence of secondary peaks in low-angle X-ray diffraction (XRD) patterns and / or by microscopic observation of cubic symmetry. The cubic symmetry of the mesopores can be identified using selected area electron diffraction (SAED) patterns and fast Fourier transform (FFT) patterns. Furthermore, mesopore symmetry can be observed by analyzing the mesopore arrangement from multiple directions, as various types of mesopore symmetries can exhibit unique pore arrangement patterns in one or more directions. In one or more embodiments, cubically symmetric ordered mesopores with space groups Ia-3d can also be observed by electron beam observation along the

[311] ,

[111] , or

[110] zone axes under a microscope. In one or more embodiments, mesoporous zeolites containing cubically symmetric ordered mesopores with space groups Fm-3m can be observed by electron beam observation along the

[001] or

[110] zone axes under a microscope. In one or more embodiments, mesoporous zeolites containing cubically symmetric ordered mesopores with Fd-3m space group can be observed by electron beam microscopy along the

[100] ,

[110] ,

[111] or

[211] zone axes.

[0028] To avoid being bound by theory, each cubic symmetry XRD peak is unique in terms of 2θ value, peak pattern, and peak intensity; however, in the case of broad XRD spectra with overlapping peaks, additional characterization techniques can be used to confirm the symmetry. Ordered cubic mesoporousness can be identified by Bragg reflections observed in low-angle XRD regions. In one or more embodiments, mesoporous zeolites containing ordered mesopores with cubic symmetry of space group Ia-3d may exhibit peaks at one or more of the (220), (321), (400), (420), or (322) reflections in the XRD spectrum. In one or more embodiments, mesoporous zeolites containing ordered mesopores with cubic symmetry of space group Fm-3m may exhibit peaks at one or more of the (111), (220), (311), (331), or (442) reflections in the XRD spectrum. In one or more embodiments, mesoporous zeolites comprising mesopores with cubic symmetry ordered arrangement of Pm-3n space groups may exhibit peaks at one or more of the (200), (210), (211), (300), (310), (411), or (331) reflections in an XRD pattern. In one or more embodiments, mesoporous zeolites comprising mesopores with cubic symmetry ordered arrangement of Pn-3m space groups may exhibit peaks at one or more of the (110), (111), (200), (211), (220), or (221) reflections in an XRD pattern. In one or more embodiments, mesoporous zeolites comprising mesopores with cubic symmetry ordered arrangement of Im-3m space groups may exhibit peaks at one or more of the (110), (200), (211), or (220) reflections in an XRD pattern. In one or more embodiments, mesoporous zeolites comprising cubically symmetrically ordered mesopores with Fd-3m space group may exhibit peaks at one or more of the (220), (222), (331) or (440) reflections in an XRD pattern.

[0029] According to one or more embodiments, mesoporous zeolites comprising a plurality of mesopores arranged in an ordered cubic symmetry can be prepared as described herein. Mesoporous zeolites can be synthesized using base-mediated reassembly, which involves the dissolution of the zeolite and its reassembly in the presence of a supramolecular template to produce mesoporous zeolites comprising a plurality of mesopores arranged in an ordered cubic symmetry.

[0030] In one or more embodiments, the rate and extent of zeolite dissolution can be controlled by using urea as an in-situ base, by adjusting the hydrothermal temperature to control urea hydrolysis, and by adjusting the pH of the solution. The degree of zeolite dissolution can be controlled by the interaction between the zeolite and the supramolecular template agent in the initial stage of dissolution, where the influence of ion-specific interactions (anionic Hofmeister effect) on supramolecular self-assembly guides the formation of mesopores with cubic symmetry.

[0031] In one or more embodiments, zeolite is contained in an aqueous suspension along with a basic reagent and a supramolecular template agent. The aqueous suspension may include an ionic co-solubilizer as an additional anion, which is different from the anion paired with the cation of the supramolecular template agent. The system is maintained under specific conditions to induce zeolite incision into oligomeric units (containing only a small number of monomer units) and to induce the oligomeric units to reassemble into a mesoscopic structure. System conditions, including the temperature and time of crystallization, the selection and concentration of the supramolecular template, and the selection and concentration of the basic reagent, are adjusted to control the zeolite incision into oligomeric units and to control the reassembly of these oligomeric units around the shape of the supramolecular template micelles. The dissolution of zeolite to the extent of oligomer formation can be promoted while minimizing monomer formation, which is controlled by selecting the supramolecular template, the basic reagent, the optional ionic co-solubilizer, and the hydrothermal conditions (temperature and time). In one or more embodiments, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, or even at least 95 wt% of the zeolite is broken down into oligomeric units. In one or more embodiments, the remaining portion of the zeolite may be in the form of monomeric units or even atomic components of the zeolite. In one or more embodiments, the interfacial curvature between the micelles and oligomeric units of the supramolecular template during reassembly can be adjusted to the desired mesoscopic structure and mesoporous content using ionic cosolvents and the Hofmeister effect.

[0032] Under effective crystallization conditions and time, using effective types of supramolecular templates and effective relative concentrations of basic reagents, zeolites can be split into oligomeric units that rearrange around shaped micelles formed by the supramolecular template, thereby forming mesoporous zeolites containing multiple mesopores arranged in an ordered cubic symmetry.

[0033] According to one or more embodiments, the curvature or shape of the micelles can result in the mesopores of the mesoporous zeolite exhibiting cubic symmetry. The formation of micelles from supramolecular template molecules depends on a variety of factors, such as the type and concentration of the supramolecular template, the presence or absence of an ionic cosolvent, the zeolite material, the crystallization temperature, the type and concentration of the basic reagent, the pH of the system, and / or the presence or absence of other reagents. Typically, at concentrations below the critical micelle concentration, the supramolecular template exists as a discrete entity. Above the critical micelle concentration, supramolecular template micelles are formed. Hydrophobic interactions in systems containing supramolecular templates alter the packing shape of the supramolecular templates, for example, forming spherical, elongated, or cylindrical micelles, which can subsequently form thermodynamically stable two- or three-dimensional liquid crystal phases with ordered mesoscopic structures.

[0034] In one or more embodiments, supramolecular templates and ionic cosolvents are selected following Hofmeister sequences, ion-specific effects, or lyotropic sequences to control the curvature or shape of micelles (e.g., spherical, elliptical, cylindrical, or monolayer structures). In embodiments, different mesoscopic structures are formed based on the anionic Hofmeister effect and supramolecular self-assembly. In aqueous solutions, anions of different sizes and charges possess different polarizabilities, charge densities, and hydration energies. When paired with positively charged supramolecular template head groups, these properties influence short-range electrostatic repulsion between head groups and hydration at the micelle interface, thereby altering the area of ​​the head groups. This ion-specific interaction can be a driving force for altering micelle curvature and inducing mesophase transitions. According to the Hofmeister series (SO4... 2 >HPO4 2 >OAc >Cl >Br NO3 ClO4 SCN Strongly hydrated ions can increase micelle curvature, while weakly hydrated ions can decrease it. The intermediate phase transition can be described using surfactant packing parameters. These parameters are given by Equation 1: Equation 1 In equation 1, g These are surfactant stacking parameters. V It is the total volume of the surfactant tail. a 0 represents the area of ​​the head group. l It is the length of the surfactant tail.

[0035] In one or more embodiments, a suitable alkaline agent comprises one or more alkaline compounds to maintain the pH of the system at a level greater than about 8. In one or more embodiments, the alkaline agent is provided in an aqueous suspension at a concentration of about 0.1 M to about 2.0 M. In one or more embodiments, the alkaline agent is provided in an aqueous suspension at a concentration of about 0.1% by weight to 5% by weight. The alkaline agent may comprise urea, ammonia, ammonium hydroxide, sodium hydroxide, or combinations thereof. In one or more embodiments, the alkaline agent comprises alkali metal hydroxides, including hydroxides of sodium, lithium, potassium, rubidium, or cesium.

[0036] In one or more embodiments, an alkaline reagent can effectively achieve controlled hydrolysis; for example, urea can be used as an alkaline reagent, reacting to form ammonium hydroxide during hydrolysis. For example, a higher concentration of urea can be used in the initial step, and alkalinity can be maintained through the gradual hydrolysis of urea. In such embodiments, the pH value increases to its maximum value relatively slowly over time, which is advantageous over adding a certain amount of other alkaline reagents (e.g., ammonium hydroxide) to the initial solution to achieve the maximum pH value. Unlike rapidly acting conventional bases, urea is pH neutral under ambient conditions and can be uniformly dispersed within the micropores of zeolite without affecting their properties.

[0037] In one or more embodiments, the basic reagent comprises an alkylammonium cation having the general formula R x H 4-x N + [A-], where X = 1 to 4, R1, R2, R3, and R4 can be the same or different C1-C30 alkyl groups, and [A-] is a counter anion, which can be OH. ,Br C1 or I In one or more embodiments, the basic reagent comprises a quaternary ammonium cation having an alkoxysilyl group, a phosphonium group, an alkyl group with a larger substituent, or an alkoxy group with a larger substituent. In one or more embodiments, the alkylammonium cation used in this respect is used as a base, rather than as a surfactant or template.

[0038] In one or more embodiments, a suitable surfactant is provided as a supramolecular template to facilitate the recombination and recrystallization of the dissolved component (oligomer) through covalent and / or electrovalent interactions. The supramolecular template may be included in the aqueous suspension at a concentration of about 0.01 M to 0.5 M. In one or more embodiments, a suitable supramolecular template is provided in the aqueous suspension at a concentration of about 0.5 wt% to 10 wt%. A suitable supramolecular template can be characterized by confined diffusion within the microporous channels of the zeolite. Diffusion of supramolecular template molecules into the microporous channels or cavities promotes the dissolution of the zeolite. In the top-down approach described herein for the synthesis of mesoporous zeolites comprising a plurality of mesopores arranged in a cubic symmetry order, such diffusion is minimized, wherein the extent to which the effective supramolecular template diffuses or partially diffuses into the zeolite channels, cavities, or window openings is minimized. Such supramolecular templates may have suitable dimensions to block this diffusion. Suitable dimensions may be based on the dimensions of the head groups and / or tail groups of the supramolecular template. In some embodiments, suitable dimensions may be based on a co-template having one or more components with suitable head groups and / or tail groups, or a template system arranged in a manner to minimize or block diffusion into zeolite channels, cavities, or window openings. Minimizing template diffusion into zeolite channels facilitates the dissolution of zeolite into oligomers and the full recombination and assembly of the mesoporous zeolite disclosed herein, comprising multiple mesopores arranged in an ordered cubic symmetry. In some embodiments, the supramolecular template refers to a supramolecular template in which at least a portion of the surfactant does not enter the zeolite pores and / or channels. For example, organosilanes (about 0.7 nm) are relatively large compared to quaternary ammonium surfactants (including cetyltrimethylammonium bromide (CTAB) (about 0.25 nm)) that do not have such bulky groups. In one or more embodiments, the supramolecular template contains long-chain linear groups (> about 0.6 nm). In one or more embodiments, the supramolecular template contains aromatic or aromatic derivative groups (> about 0.6 nm). In one or more embodiments, the supramolecular template contains one or more bulky groups whose size is determined based on modeling the molecular size as a cuboid with sizes A, B, and C (using the van der Waals radius of a single atom), wherein one or more, two or more, or all three of sizes A, B, and C are sufficiently close in size or sufficiently large in size to restrict their diffusion into the micropores of the zeolite.

[0039] In one or more embodiments, the effective surfactant serving as a supramolecular template comprises at least one moiety as a head or tail group, the moiety being selected from organosilanes, hydroxysilyl, alkoxysilyl, aromatic groups, branched alkyl groups, sulfonate groups, carboxylate groups, phosphate groups, and combinations thereof. In one or more further embodiments, the effective supramolecular template is an organosilane comprising at least one hydroxysilyl group as a head group moiety. In one or more embodiments, the effective supramolecular template is an organosilane comprising at least one hydroxysilyl group as a tail group moiety. In one or more further embodiments, the effective supramolecular template is an organosilane comprising at least one alkoxysilyl group as a head group moiety. In one or more embodiments, the effective supramolecular template is an organosilane comprising at least one alkoxysilyl group as a tail group moiety. In one or more further embodiments, the effective supramolecular template comprises at least one aromatic group as a head group moiety. In one or more further embodiments, the effective supramolecular template comprises at least one aromatic group as a tail group moiety. In one or more further embodiments, the effective supramolecular template comprises at least one branched alkyl group as a head group moiety. In one or more embodiments, the effective supramolecular template comprises at least one branched alkyl group as a tail group portion. In one or more embodiments, the effective supramolecular template comprises at least one sulfonate group as a head group portion. In one or more further embodiments, the effective supramolecular template comprises at least one sulfonate group as a tail group portion. In one or more additional embodiments, the effective supramolecular template comprises at least one carboxylate group as a head group portion. In one or more embodiments, the effective supramolecular template comprises at least one carboxylate group as a tail group portion. In one or more embodiments, the effective supramolecular template comprises at least one phosphate group as a head group portion. In one or more additional embodiments, the effective supramolecular template comprises at least one phosphate group as a tail group portion. These portions are characterized by restricting diffusion into one or more sizes within the zeolite pores. In some embodiments, where the zeolite is characterized by pores of various sizes, the selected portions are characterized by restricting diffusion into one or more sizes within the largest pores of the zeolite.

[0040] In one or more embodiments, the effective supramolecular template comprises at least one cationic moiety. In one or more further embodiments, the effective supramolecular template comprises at least one cationic moiety selected from quaternary ammonium and phosphorus moieties. In one or more additional embodiments, the effective supramolecular template comprises at least one quaternary ammonium group having a terminal alkyl group containing 6 to 24 carbon atoms. In one or more embodiments, the effective supramolecular template comprises two quaternary ammonium groups, wherein the alkyl group bridging the two quaternary ammonium groups contains 1 to 10 carbon atoms. In one or more additional embodiments, the effective supramolecular template comprises at least one quaternary ammonium group and at least one constitutive group, as described above in the head group portion. In one or more further embodiments, the effective supramolecular template comprises at least one quaternary ammonium group and at least one constitutive group, as described above in the tail group portion. In one or more embodiments, the effective supramolecular template comprises at least one quaternary ammonium group, at least one constitutive group (as described above in the head group portion), and an alkyl group containing 1 to 10 carbon atoms bridging at least one quaternary ammonium group and at least one head group. In one or more further embodiments, the effective supramolecular template comprises at least one quaternary ammonium group, at least one constituent group (as described above for the tail group portion), and an alkyl group containing 1 to 10 carbon atoms bridging at least one quaternary ammonium group and at least one tail group.

[0041] In one or more embodiments, the effective supramolecular template comprises a quaternary ammonium compound and a constituent group comprising one or more bulky organosilane or alkoxysilane substituents. In one or more additional embodiments, the effective supramolecular template comprises a quaternary ammonium compound and a constituent group comprising one or more long-chain organosilane or alkoxysilane substituents. In some embodiments, the effective supramolecular template cation comprises a derivative of dimethyloctadecyl(3-trimethoxysilyl-propyl)ammonium or a dimethyloctadecyl(3-trimethoxysilyl-propyl)ammonium. In one or more embodiments, the effective supramolecular template cation comprises a derivative of dimethylhexadecyl(3-trimethoxysilyl-propyl)ammonium or a dimethylhexadecyl(3-trimethoxysilyl-propyl)ammonium. In one or more other embodiments, the effective supramolecular template cation comprises a diacyloxy amphiphilic organosilanes, such as [2,3-bis(dodecanoyloxy)propyl](3-(trimethoxysilyl)propyl)-dimethylammonium or derivatives of [2,3-bis(dodecanoyloxy)propyl](3-(trimethoxysilyl)propyl)-dimethylammonium.

[0042] In one or more embodiments, the effective supramolecular template comprises a quaternary phosphonium compound and a constituent group comprising one or more bulky aromatic substituents. In one or more embodiments, the effective supramolecular template comprises a quaternary phosphonium compound and a constituent group comprising one or more bulky alkoxysilyl or organosilanes.

[0043] In one or more embodiments, the effective supramolecular template includes a tail group portion selected from: an aromatic group containing 6 to 50, 6 to 25, 10 to 50, or 10 to 25 carbon atoms; an alkyl group containing 1 to 50, 1 to 25, 5 to 50, 5 to 25, 10 to 50, or 10 to 25 carbon atoms; an aryl group containing 1 to 50, 1 to 25, 5 to 50, 5 to 25, 10 to 50, or 10 to 25 carbon atoms; or a combination of an aromatic group and an alkyl group having up to 50 carbon atoms. In one or more embodiments, the effective supramolecular template comprises a head group portion selected from: aromatic groups containing 6 to 50, 6 to 25, 10 to 50, or 10 to 25 carbon atoms; alkyl groups containing 1 to 50, 1 to 25, 5 to 50, 5 to 25, 10 to 50, or 10 to 25 carbon atoms; aryl groups containing 1 to 50, 1 to 25, 5 to 50, 5 to 25, 10 to 50, or 10 to 25 carbon atoms; or a combination of aromatic and alkyl groups having up to 50 carbon atoms. In one or more embodiments, the effective supramolecular template comprises a co-templater selected from quaternary ammonium compounds (including, for example, quaternary alkylammonium cationic compounds) and quaternary phosphonium compounds.

[0044] In one or more embodiments, the effective supramolecular template comprises: (a) at least one of the following: an aromatic quaternary ammonium compound, a branched alkyl quaternary ammonium compound, an alkylbenzene sulfonate (salt), an alkylbenzene phosphonate (salt), an alkylbenzene carboxylate (salt), or a substituted phosphonium cation; and (b1) a constituent group comprising at least one organosilane, hydroxysilyl, alkoxysilyl, aromatic group, branched alkyl, sulfonate, carboxylate, or phosphate group as a head group; or (b2) a constituent group comprising at least one organosilane, hydroxysilyl, alkoxysilyl, aromatic group, branched alkyl, sulfonate, carboxylate, or phosphate group as a tail group. In one or more embodiments, the effective supramolecular template comprises a sulfonate group (a non-limiting example is sulfonated bis(2-hydroxy-5-dodecylphenyl)methane (SBHDM)). In one or more further embodiments, the effective supramolecular template comprises a carboxylate group (a non-limiting example is sodium 4-(octyloxy)benzoate). In one or more other embodiments, the effective supramolecular template comprises a phosphonate group (a non-limiting example is tetradecyl(1,4-benzene)bisphosphonate). In one or more embodiments, the effective supramolecular template comprises an aromatic group (a non-limiting example is benzylhexadecyldimethylammonium chloride). In one or more other embodiments, the effective supramolecular template comprises an aliphatic group (a non-limiting example is tetraoctylammonium chloride).

[0045] The supramolecular template is provided in the form of a cation / anion pair. In one or more embodiments, the supramolecular template described above has a cation and anion (e.g., Cl-) - ,Br - OH - P - and I - Pairing. In one or more further embodiments, the cation of the supramolecular template as described above is paired with an anion (e.g., Cl). - ,Br - and OH -In one or more embodiments, the effective supramolecular template comprises dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (commonly abbreviated as "TPOAC") or a derivative of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride. In one or more further embodiments, the effective supramolecular template comprises dimethylhexadecyl[3-(trimethoxysilyl)propyl]ammonium chloride or a derivative of dimethylhexadecyl[3-(trimethoxysilyl)propyl]ammonium chloride. In one or more further embodiments, the effective supramolecular template comprises [2,3-bis(dodecanoyloxy)propyl](3-(trimethoxysilyl)propyl)-dimethylammonium iodide or a derivative of [2,3-bis(dodecanoyloxy)propyl](3-(trimethoxysilyl)propyl)-dimethylammonium iodide.

[0046] In one or more embodiments, the system comprises an effective amount of an ionic cosolvent (i.e., in addition to anions paired with the supramolecular template). In one or more embodiments using an ionic cosolvent, the ionic cosolvent is provided in an aqueous suspension at a concentration of about 0.01 M to about 0.5 M. In one or more embodiments using an ionic cosolvent, the ionic cosolvent is provided in an aqueous suspension at a concentration of about 0.01 wt% to about 5 wt%. In one or more embodiments, the ionic cosolvent is selected from CO3. 2 SO4 2 S2O3 2 H2PO4 F Cl ,Br NO3 I ClO4 SCN and C6H5O8 3 (Citrate). In one or more embodiments, ionic cosolvents are selected based on the Hofmeister sequence / colloidal ion sequence to control the curvature / shape of micelles, thereby producing the desired cubic meso-symmetry. In one or more embodiments, nitrate (NO3) This is an ionic cosolvent selected based on the Hofmeister sequence / sensitive ion sequence to control the curvature / shape of micelles, thereby producing mesoporous zeolites containing multiple mesopores arranged in an ordered cubic symmetry. In one or more embodiments using nitrates as ionic cosolvents, nitrates such as ammonium nitrate or metal nitrates are used, wherein the metal can be an alkali metal, alkaline earth metal, transition metal, noble metal, or rare earth metal.

[0047] According to one or more embodiments described herein, a method for forming a mesoporous zeolite comprising a plurality of mesopores arranged in an ordered cubic symmetry includes: decomposing the zeolite into oligomeric components by base-mediated dissolution / fractionation, and recombining the oligomeric components by supramolecular templated and, in some embodiments, by the Hofmeister effect. The zeolite is provided in crystalline form. An effective amount of an alkaline reagent and an effective amount of a surfactant for supramolecular templated formation are added to form an aqueous suspension, and the suspension is maintained under hydrothermal conditions to form oligomeric units of the zeolite. The supramolecular template molecules form micelles of a shape, and the oligomeric zeolite units reassemble and crystallize around these micelles, forming an ordered mesoscopic structure with cubic symmetric mesopores and mesopore walls composed of oligomeric zeolite units, thereby preserving the micropores of the underlying zeolite structure. In one or more embodiments, the micelles of a shape can be removed, for example, by chemical methods such as solvent extraction, chemical oxidation, or ionic liquid treatment; or by physical methods such as calcination, supercritical CO2, microwave-assisted treatment, ultrasonic-assisted treatment, ozone treatment, or plasma technology. Unbound by theory, it is believed that the removal of micelles forms at least a portion of the mesopores in the mesoporous zeolite, wherein the mesopores exist in the spaces that were once occupied by micelles.

[0048] In this process, an effective amount of solvent can be used. In one or more embodiments, the solvent comprises water. In one or more embodiments, the solvent is water in the presence of a co-solvent selected from polar solvents, nonpolar solvents, and pore-swelling agents (e.g., 1,3,5-trimethylbenzene). In one or more embodiments, the solvent is selected from polar solvents, nonpolar solvents, and pore-swelling agents (e.g., 1,3,5-trimethylbenzene), without water. In one embodiment, the mixture components are added to the reaction vessel along with water before heating. Unbound by theory, water can achieve thorough mixing, resulting in a more uniform distribution of the suspension components, ultimately producing a more desirable product because the properties of each crystal are better matched to the next.

[0049] According to various embodiments, the suspension components can be combined in any suitable order and thoroughly mixed to form a uniform distribution of the suspension components. The suspension can be maintained under autogenous pressure (from the components, or from the components and gases purged into the vessel before heating) in an autoclave or other suitable vessel under agitated conditions (e.g., stirring, tumbling, and / or shaking). The mixing of the suspension components is carried out between about 20°C and about 60°C.

[0050] The splitting and reassembly steps can occur during hydrothermal treatment to form a solid product (containing multiple mesoporous zeolites with cubically ordered mesopores) suspended in the supernatant (mother liquor). Hydrothermal treatment can be carried out at temperatures of approximately 70°C to 250°C, 70°C to 210°C, 70°C to 180°C, 70°C to 150°C, 90°C to 250°C, 90°C to 210°C, 90°C to 180°C, 90°C to 150°C, 110°C to 250°C, 110°C to 210°C, 110°C to 180°C, or 110°C to 150°C; and at pressures of approximately atmospheric pressure to autogenous pressure for durations of approximately 4 hours to 168 hours, 12 hours to 168 hours, 24 hours to 168 hours, 4 hours to 96 hours, 12 hours to 96 hours, or 24 hours to 96 hours. In one or more embodiments, the hydrothermal treatment is carried out in the same container as the container used for mixing, or the suspension is transferred to another container (e.g., another autoclave or low-pressure vessel). In one or more embodiments, the container for hydrothermal treatment is static. In one or more embodiments, the container for hydrothermal treatment is under stirring conditions sufficient to suspend the components.

[0051] The solid product, namely mesoporous zeolite containing multiple mesopores arranged in an ordered cubic symmetry, is recovered using techniques such as centrifugation, decantation, gravity sedimentation, vacuum filtration, pressure filtration, or drum filtration. The recovered solid product is dried, for example, at a temperature of about 50°C to 150°C under atmospheric pressure or vacuum conditions, for about 0.5 hours to 96 hours.

[0052] In one or more embodiments, the solid product is calcined to remove the supramolecular template remaining in the mesopores and other components from the mesopores and / or the micropores of the discrete zeolite unit cells. In embodiments where calcination is performed, the calcination conditions may include temperatures in the following ranges: about 350°C to 650°C, 350°C to 600°C, 350°C to 550°C, 500°C to 650°C, 500°C to 600°C, or 500°C to 550°C; at atmospheric pressure or under vacuum; and for the following durations: about 2.5 hours to 24 hours, 2.5 hours to 12 hours, 5 hours to 24 hours, or 5 hours to 12 hours. Calcination may be carried out at a heating rate of about 0.1°C / min to 10°C / min. In one or more embodiments, calcination may first be carried out at a heating rate of about 0.1°C / min to 5°C / min to a temperature between about 100°C and 150°C, and held for about 1 hour to 12 hours, and then raised to a higher temperature, with a final holding time of about 1 hour to 12 hours.

[0053] According to one or more embodiments disclosed herein, a mesoporous zeolite comprising a plurality of mesopores arranged in an ordered cubic symmetry can be used as a “starting zeolite” and then dehydroxylated to form a dehydroxylated zeolite. Typically, a starting zeolite can refer to a zeolite that is substantially undehydroxylated and contains at least a majority of ortho-hydroxyl groups. As commonly understood by those skilled in the art, dehydroxylation involves a reaction that forms water molecules by releasing hydroxyl groups and allowing them to bind with protons. The starting zeolite may primarily contain ortho-silanol functional groups. In one or more embodiments, dehydroxylating the starting zeolite can form isolated terminal silanol functional groups containing hydroxyl groups bonded to silicon atoms in the microporous framework of the dehydroxylated zeolite. Such isolated silanol functional groups may be represented as ≡Si-OH.

[0054] As described herein, a “silanol functional group” refers to a ≡Si-OH group. A silanol group typically contains a silicon atom and a hydroxyl group (-OH). As described herein, a “terminal” functional group is a functional group that is bonded to only one other atom. For example, a silanol functional group can be a terminal group by bonding to only one other atom (e.g., a silicon atom in a microporous framework). As described herein, an “isolated silanol functional group” is a silanol functional group that is sufficiently far apart to avoid hydrogen bonding interactions with other silanol functional groups. These isolated silanol functional groups are typically non-adjacent to other silanol functional groups on a zeolite. Typically, in zeolites comprising silicon and oxygen atoms, “adjacent silanol” refers to a silanol directly bonded by bridging oxygen atoms. As those skilled in the art will understand, isolated silanol functional groups can be visualized by FT-IR and / or 1 Identification can be performed using ¹H-NMR. For example, the characteristics of isolated silanol functional groups can be detected by ¹H-NMR at approximately 3747 cm⁻¹. - There is a sharp and intense FT-IR band at ¹, and / or at approximately 1.8 ppm. 1 Characterized by ¹H-NMR chemical shift. In the embodiment described herein, FT-IR at 3747 cm⁻¹ - ¹Location or vicinity and / or 1 Peaks at or near 1.8 ppm in H-NMR indicate the presence of dehydroxylated zeolite, while the absence of peaks at or near these values ​​indicates the presence of primary zeolite.

[0055] The isolated silanol functional group contrasts with the ortho-silanol functional group, in which two silanol functional groups are "adjacent" to each other by bonding to a bridging oxygen atom, respectively. Chemical structure #2A depicts the isolated silanol functional group, while chemical structure #2B depicts the ortho-silanol functional group. In the ortho-silanol functional group, an oxygen atom of one silanol functional group forms a hydrogen bond with a hydrogen atom of the adjacent silanol functional group. The ortho-silanol functional group exhibits high FT-IR and... 1 Different spectral bands can be displayed in H-NMR, such as 3520 cm⁻¹ in FT-IR. - ¹or 3720 cm - ¹, and 1 3 ppm in H-NMR.

[0056]

[0057] Chemical structure #2A

[0058] Chemical structure #2B As described in this article, "dehydroxylated zeolite" refers to zeolite material that has undergone at least partial dehydroxylation (i.e., hydrogen and oxygen atoms are released from the initial zeolite, along with water). Unbound by theory, it is believed that the dehydroxylation reaction forms water molecules through the hydroxyl groups of the first methylsilanol and the hydrogen groups of the second methylsilanol in the zeolite. The remaining oxygen atoms in the second methylsilanol functional group form siloxane groups in the zeolite (i.e., (≡Si-O-Si≡)), sometimes referred to as strained siloxane bridges. Typically, strained siloxane bridges are formed during the dehydroxylation reaction, rather than during the initial zeolite formation process.

[0059] In one or more embodiments, the initial zeolite (and the dehydroxylated zeolite) contains aluminum in addition to silicon and oxygen. For example, ZSM-5 zeolite may contain such atoms. In embodiments where aluminum is present, the microporous framework of the dehydroxylated zeolite may include Brønsted silanol functional groups. In these Brønsted silanol functional groups, each oxygen atom can bridge a silicon atom and an aluminum atom in the microporous framework. Such Brønsted silanol functional groups can be represented as [≡Si-O(H)]. Al≡).

[0060] Chemical structure #3 depicts an example of an aluminosilicate zeolite framework structure containing the isolated terminal silanol functional group and the Brønsted acid silanol functional group described herein.

[0061]

[0062] Chemical structure #3 According to one or more embodiments, the dehydroxylation of the initial zeolite can be carried out by heating the initial zeolite under vacuum at elevated temperatures, for example, 700°C to 1100°C. It is believed that, according to one or more embodiments described herein, heating at temperatures below 650°C may be insufficient to form terminal isolated silanol functional groups. However, heating at temperatures above 1100°C may result in the elimination of terminal isolated silanol functional groups, or a reduction in the concentration of such functional groups to a level sufficiently low that the subsequent formation of organometallic moieties through contact with organometallic chemicals cannot be observed, as will be described later herein.

[0063] According to the implementation scheme, the heating temperature can be 650°C to 700°C, 700°C to 750°C, 750°C to 800°C, 800°C to 850°C, 850°C to 900°C, 900°C to 950°C, 950°C to 1000°C, 1000°C to 1050°C, 1050°C to 1100°C, or any combination of these ranges. For example, a temperature range from 650°C to any specified value is considered, as is a temperature range from any specified value to 1100°C. As described herein, vacuum pressure refers to any pressure below atmospheric pressure. According to some implementation schemes, the pressure during the heating process can be below 10... 2 mbar, below 10 2.5 mbar, below 10 3 mbar, below 10 3.5 mbar, below 10 4 mbar, even below 10 4.5 mbar. The heating time can be long enough to allow the zeolite to reach thermal equilibrium with the oven or other heating equipment used. For example, heating times greater than 8 hours, 12 hours, or 18 hours can be used. For example, a heating time of 24 hours can be used.

[0064] Unbound by any particular theory, it is believed that higher heating temperatures during dehydroxylation are associated with a reduction in terminal silanols present on the dehydroxylated zeolite. However, it is also believed that higher heating temperatures during dehydroxylation are associated with a greater number of strained siloxanes. For example, when the initial zeolite is heated to 700 °C during dehydroxylation, the concentration of isolated terminal silanol groups can be at least 0.4 mmol / g, and in some embodiments, approximately 0.45 mmol / g, as measured by lithium methyl titration. Dehydroxylation at 1100 °C results in a significant reduction in both isolated terminal silanols and isolated Brønsted silanols. In some embodiments, the number of isolated terminal silanol groups present is less than 10% of that at 700 °C when dehydroxylation is performed using 1100 °C. However, it is believed that the number of strained siloxane groups is significantly greater at these higher dehydroxylation temperatures. As described below, dehydroxylation temperature can affect amine functionalization performed via ammonia treatment.

[0065] In one or more embodiments, the dehydroxylated zeolite can be treated to form a modified zeolite. Typically, to form a modified zeolite, ammonia or other amine compounds (e.g., aniline) can be contacted and / or reacted with the dehydroxylated zeolite at elevated temperatures. According to one or more embodiments, the ammonia treatment temperature can be from 200°C to 900°C.

[0066] In one or more embodiments, it is believed that contact between dehydroxylated zeolite and ammonia can lead to the formation of modified zeolite. Chemical structure #4 describes the reaction scheme for the conversion of dehydroxylated zeolite into modified zeolite. Specifically, isolated terminal silanol functional groups can be converted into primary amine functional groups on the modified zeolite. Furthermore, in embodiments where aluminum is present in the zeolite framework and Brønsted silanol is present in the dehydroxylated zeolite, a primary amine can be formed, wherein the nitrogen atom of the primary amine is coordinated with an aluminum atom.

[0067]

[0068] Chemical structure #4 As shown in chemical structure #4, in one or more embodiments, an isolated terminal amine functional group may be bonded to a silicon atom of the microporous framework (sometimes referred to herein as a silylamine group). The isolated terminal amine functional group may be a primary amine functional group, such that the nitrogen atom of the primary amine functional group is bonded to two hydrogen atoms and one silicon atom of the microporous framework. Similar to the description of the isolation and termination of silanol groups in dehydroxylated zeolites, an isolated terminal amine functional group is defined as an amine functional group that is terminated by bonding to only one other atom (i.e., in this case, a silicon atom of the zeolite framework) and is isolated by not being adjacent to other amine functional groups. Typically, isolated silanol functional groups in dehydroxylated zeolites can be converted into their corresponding isolated amine functional groups in modified zeolites.

[0069] In one or more embodiments, the modified zeolite may contain 0.5 mmol / g to 3.0 mmol / g of isolated terminal primary amine functional groups. For example, the modified zeolite may contain isolated terminal primary amine functional groups in the following ranges: 0.5 mmol / g to 3.0 mmol / g, 1.0 mmol / g to 3.0 mmol / g, 1.5 mmol / g to 3.0 mmol / g, 2.0 mmol / g to 3.0 mmol / g, 2.5 mmol / g to 3.0 mmol / g, 0.5 mmol / g to 2.5 mmol / g, 0.5 mmol / g to 2.0 mmol / g, 0.5 mmol / g to 1.5 mmol / g, 0.5 mmol / g to 1.0 mmol / g, or any range or combination of ranges formed by these terminals.

[0070] Furthermore, as shown in chemical structure #4, in embodiments where aluminum is present in the zeolite, the modified zeolite may contain a primary amine group (sometimes referred to as a silylamine group) bonded to a framework silicon atom, which is coordinated to an aluminum atom in the framework structure. As described herein, a silylamine group refers to ≡Si-NH2 in the zeolite. The silylamine group therefore contains a nitrogen atom bonded to a first hydrogen atom, a second hydrogen atom, and a silicon atom in the zeolite framework structure. Since the nitrogen atom is bonded to two hydrogen atoms and one non-hydrogen atom (silicon in the zeolite framework), the silylamine may comprise a primary amine. The nitrogen atom is further coordinated to an aluminum atom in the zeolite framework, such as [≡Si-NH2]. As shown in Al≡].

[0071] According to several embodiments, the reaction of chemical structure #4 can occur at a temperature of at least 400°C. Typically, additional reactions may occur with increasing temperature, as described below. It is believed that the occurrence of additional reactions can be minimized when temperatures below 600°C are used in the amine functionalization step. In one or more embodiments, the amount of primary amine functional group can be quantified by nitrogen elemental analysis or by titration with BuLi or MeLi.

[0072] In one or more embodiments, additional reactions that can form other amine functional groups occur when a temperature of at least 600°C is used during the amine functionalization process. Chemical structure #5 shows secondary amine functional groups that can be formed at relatively high temperatures during ammonia treatment.

[0073]

[0074] Chemical structure #5 In one or more embodiments, as shown in chemical structure #6, silazane groups can be formed. As described herein, silazane refers to the ≡Si-NH-Si≡ group. Since the nitrogen atom is bonded to two silicon atoms, silazane can be considered a secondary amine. In embodiments where alumina is present in the zeolite, the silazane coordinated to the aluminum atom can be present in the modified zeolite. Chemical structure #6 below illustrates a mechanism by which an isolated terminal silazane group (previously formed by ammonia treatment at at least 400°C) and a strained siloxane bridge (formed during high-temperature dehydroxylation) can be converted into a silazane. As shown in chemical structure #6, in the presence of aluminum in the zeolite microstructure, the silazane functional group can be coordinated to the aluminum atom. The formation mechanism of silazane coordinated to the aluminum atom can be similar to the mechanism shown in chemical structure #6. The silazane bridge can be detected by FT-IR at 3386 cm⁻¹. - The vibrational band at ¹ is characterized.

[0075]

[0076] Chemical structure #6 In one or more embodiments, the modified zeolite may contain 1.5 mmol / g to 3.0 mmol / g of silazane functional groups. For example, without limitation, the modified zeolite may contain silazane functional groups in the following ranges: 1.5 mmol / g to 3.0 mmol / g, 2.0 mmol / g to 3.0 mmol / g, 2.5 mmol / g to 3.0 mmol / g, 1.5 mmol / g to 2.5 mmol / g, 1.5 mmol / g to 2.0 mmol / g, or any range or combination of these endpoints. Without being bound by theory, the concentration of the silazane functional groups may depend at least in part on the temperature of the dehydroxylation process and the amine functionalization step.

[0077] Depending on the implementation, the temperature combination during dehydroxylation and amine functional group formation promotes the presence of specific functional groups in the modified zeolite. Various combinations are described herein. However, it should be understood that in many embodiments, the heating temperature during amine functionalization via ammonia contact is lower than or equal to the dehydroxylation temperature. In such embodiments, the degree of dehydroxylation can be controlled by the dehydroxylation temperature, since no higher temperature is used after dehydroxylation.

[0078] In one or more embodiments, the dehydroxylation temperature can be relatively low (e.g., 800°C or lower), and the amine functionalization temperature can be any temperature below or equal to the dehydroxylation heating temperature. As described herein, the relatively low dehydroxylation temperature promotes the formation of isolated terminal silanol groups. In such embodiments, the concentration of strained siloxane bridges can be relatively low. Chemical structure #7 shows a general reaction scheme for such embodiments. The unstrained siloxane groups (present in the initial zeolite) are substantially unaffected by ammonia treatment at relatively low temperatures. Such embodiments can be rich in isolated terminal silanol groups and can be used for grafting organometallic moieties. As described herein, such embodiments may be desirable for organometallic grafting.

[0079]

[0080] Chemical structure #7 According to another embodiment, the dehydroxylation heating temperature is relatively high (e.g., greater than 800 °C or even greater than 900 °C). As described herein, such dehydroxylation temperatures may favor the formation of strained siloxane bridges rather than isolated terminal silanol moieties. Chemical structure #8 describes a reaction mechanism by which the strained siloxane moieties of dehydroxylated zeolites can form hydroxyl and amino groups at temperatures of 200 °C and above, followed by the formation of bis(silylamine) pairing structures at temperatures of at least 400 °C. These silylamine pairing structures may not be suitable for organometallic grafting applications because they are adjacent to each other and do not constitute “isolated” amine moieties as described herein. While they may not be strictly directly adjacent, they are positionally close because they are formed by the breaking of siloxane bridges.

[0081]

[0082] Chemical structure #8 Unbound by theory, it is believed that ammonia treatment at temperatures exceeding 900°C will lead to the formation of oxynitride functional groups. Such materials contain nitrogen atoms bonded to three silicon atoms (i.e., tertiary amines). Such tertiary amines may not be desired in the embodiments disclosed herein. Chemical structure #9 depicts the reaction pathway for the formation of silicon oxynitride by exposure to ammonia at temperatures exceeding 900°C.

[0083]

[0084] Chemical structure #9 According to another embodiment, modified zeolites comprising isolated terminal silanol moieties and silazane groups coordinated with aluminum atoms in the microporous framework can be prepared. Without being bound by any particular theory, it is believed that a relatively low dehydroxylation temperature combined with a very low ammonia contact temperature can produce such zeolites. As described herein, dehydroxylation temperatures below or equal to 800 °C can form isolated terminal amine functional groups and Brønsted silanol functional groups bridging the silicon and aluminum atoms in the microporous framework. Using temperatures below 300 °C during amine modification may not significantly affect the isolated terminal amine functional groups, but may form terminal primary amine functional groups bonded to the silicon atoms in the microporous framework, wherein the terminal amine functional groups are coordinated with the aluminum atoms in the microporous framework.

[0085] In one or more embodiments, the modified zeolite may comprise a Brønsted acid moiety and a Lewis acid moiety. As described herein, a "Brønsted acid moiety" refers to a moiety capable of donating protons to a base, and a "Lewis acid moiety" refers to a moiety acting as an electron pair acceptor. The Lewis acid moiety can be formed in defects in the zeolite, in amorphous portions of the zeolite, and in extra-framework aluminum (Al) compounds. As previously mentioned, the Brønsted acid moiety may comprise [≡Si-O(H)]. [Al≡]. In one or more embodiments, the modified zeolite may comprise a Lewis acid portion and a Brønsted acid portion, wherein the ratio of the Lewis acid portion to the Brønsted acid portion is 6.2 to 7.9. For example, the ratio of the Lewis acid portion to the Brønsted acid portion in the modified zeolite may be 6.2 to 7.9, 6.4 to 7.9, 6.6 to 7.9, 6.8 to 7.9, 7.0 to 7.9, 7.2 to 7.9, 7.4 to 7.9, 7.6 to 7.9, 7.8 to 7.9, 6.2 to 7.7, 6.2 to 7.5, 6.2 to 7.3, 6.2 to 7.1, 6.2 to 6.9, 6.2 to 6.7, 6.2 to 6.5, 6.2 to 6.3, or any range or combination of ranges formed by these endpoints.

[0086] In one or more embodiments, the total acidity of the modified zeolite can be from 100 µmol / g to 250 µmol / g. As described herein, “total acidity” refers to the amount of acid sites in a portion of the zeolite material. Total acidity is determined ex-situ. To avoid being bound by theory, the acidity of the zeolite under in-situ reaction conditions can vary due to the high temperature and pressure conditions. For example, the total acidity of modified zeolites can be 100 µmol / g to 250 µmol / g, 120 µmol / g to 250 µmol / g, 140 µmol / g to 250 µmol / g, 160 µmol / g to 250 µmol / g, 180 µmol / g to 250 µmol / g, 200 µmol / g to 250 µmol / g, 220 µmol / g to 250 µmol / g, 240 µmol / g to 250 µmol / g, 100 µmol / g to 240 µmol / g, 100 µmol / g to 230 µmol / g, 100 µmol / g to 220 µmol / g, 100 µmol / g to 210 µmol / g, 100 µmol / g to 200 µmol / g, 100 µmol / g to 190 µmol / g, 100 µmol / g to 180 µmol / g. The values ​​are µmol / g, 100 µmol / g to 170 µmol / g, 100 µmol / g to 160 µmol / g, 100 µmol / g to 150 µmol / g, 100 µmol / g to 140 µmol / g, 100 µmol / g to 130 µmol / g, 100 µmol / g to 120 µmol / g, 100 µmol / g to 110 µmol / g, or any range or combination of these endpoints. Without being bound by theory, the overall acidity of zeolite materials is influenced by the presence of silanol functional groups. Replacing silanol functional groups with amine functional groups can alter the acidity and functional properties of modified zeolites.

[0087] It should be understood that, according to one or more currently disclosed embodiments, various functional groups of zeolites can be detected by FT-IR and / or 1 Identification can be performed using ¹H-NMR methods. When zeolites "contain" such portions, this introduction can be detected by FT-IR and / or... 1 This can be confirmed by the presence of peaks at or near the corresponding band in ¹H-NMR. Those skilled in the art will understand this type of detection method.

[0088] In one or more embodiments, the modified zeolites disclosed herein are suitable for use as catalysts in refining, petrochemical, and chemical processing. For example, hydrocarbon feedstocks can be contacted with the modified zeolites described herein to form products. Table 1 shows some of the anticipated catalytic functions of the modified zeolites of this disclosure and provides potentially desirable zeolite framework types. However, it should be understood that the description in Table 1 should not be construed as limiting the possible uses of the modified zeolites of this disclosure.

[0089] Table 1

[0090] According to other embodiments, the amine-functionalized zeolites of this disclosure can be used for separation and / or large-scale capture processes. For example, the amine-functionalized zeolites of this disclosure can be used to adsorb CO2 and to separate p-xylene from its isomers.

[0091] According to one or more other embodiments, the modified zeolite of this disclosure can be further modified by introducing an organometallic moiety. Such organometallic moiety can be grafted onto amine-functionalized zeolite. Without being bound by theory, it is believed that the organometallic moiety can be bonded to isolated terminal primary amine functional groups of amine-modified zeolite through processes such as impregnation.

[0092] Example The following examples will further illustrate various embodiments of the methods and systems for forming functionalized zeolites. These examples are illustrative in nature and should not be construed as limiting the subject matter of this disclosure.

[0093] Example 1 – Synthesis of zeolites containing mesoporous structures with cubic symmetry 1.2 g of urea was dissolved in 60.0 g of water to form a homogeneous solution. 0.2 g of ammonium nitrate (NH4NO3) was added to this mixture, and the mixture was stirred to form a homogeneous solution. 2.0 g of Y zeolite (purchased from Zeolyst International, product name CBV 720) was added to the mixture, and the mixture was stirred for 10 minutes. Subsequently, 3.0 mL of an organosilane, namely dimethyloctadecyl(3-trimethoxysilyl-propyl)ammonium chloride (42.0 wt% methanol solution), was added to the mixture. The resulting solution was stirred for 0.5 hours, and then hydrothermally treated at 130 °C for 72 hours. The resulting mixture was filtered, washed with water, and dried at 120 °C for 24 hours. The synthesized product was heated to 550 °C in air at a heating rate of 60 °C / hour and calcined at this temperature for 6 hours to obtain a zeolite containing mesopores with a cubic symmetry-ordered arrangement.

[0094] The zeolite of Example 1, containing mesopores with cubic symmetry, was analyzed by transmission electron microscopy (TEM) using a PEI-Titan ST electron microscope operating at 300 kV. Figure 1Aand Figure 1B The image is a transmission electron microscope image of the zeolite with cubically symmetrically ordered mesoporous structures shown in Example 1, showing cubic mesoporous channels along the

[110] and

[111] directions, with FAU micropore channels existing within the walls of the mesoporous structure. Figure 1A The image shows transmission electron micrographs at the 100-nanometer scale. Figure 1B This displays transmission electron micrographs at the 20 nm scale in the

[110] and

[111] directions. Furthermore, Figure 1C A schematic diagram of the FAU unit cell and its arrangement to provide mesopores with cubic symmetry is depicted.

[0095] The zeolite containing mesoporous structures with cubic symmetry of Example 1 was analyzed by powder X-ray diffraction (XRD) using a Bruker D8 dual diffractometer, operated at 40 kV and 40 mA, with Cu Kα radiation (λ = 0.154 nm) and a step size of 0.02°. Figure 2A A low-angle XRD pattern of the zeolite of Example 1, comprising mesoporous structures with an ordered cubic symmetry arrangement, is depicted. Figure 2A As shown, the XRD pattern reveals reflections at 211, 220, 321, 400, 420, and 332, characteristic of the cubic mesoporous symmetry of the Ia-3d space group. Figure 2A The reflections at 321, 400, 420, and 332 are shown at 8x magnification. Figure 2B High-angle XRD patterns (diffraction pattern 201) of the zeolite comprising mesoporous structures with cubic symmetry in Example 1 and high-angle XRD patterns (diffraction pattern 202) of the Y zeolite are depicted. Figure 2B It can be clearly seen that the underlying zeolite structure is preserved, and the peaks of the zeolite containing mesoporous structures with cubic symmetry in Example 1 are consistent with the peaks of Y zeolite.

[0096] Example 2 – Dehydroxylation of zeolite comprising mesoporous structures with cubic symmetry ordered arrangement, as described in Example 1. The zeolite of Example 1, comprising mesoporous structures with cubic symmetry and ordered arrangement, was dehydroxylated at 700°C to form a dehydroxylated zeolite. Two grams of the zeolite of Example 1, comprising mesoporous structures with cubic symmetry and ordered arrangement, were added to a quartz reactor equipped with a tubular furnace. The reactor was subjected to a temperature of 700°C and a 10-day heating process. 5The zeolite of Example 1, comprising mesoporous structures with cubic symmetry, was treated for 16 hours under a pressure of mbar. The heating rate in the tube furnace was 2.8 °C / min. The dehydroxylation process resulted in the condensation of ortho-hydroxyl surface groups, forming monomethylsilanols (≡Si-OH) and Brønsted acids (≡Si-OH->Al≡), as well as siloxane bridges (≡Si-O-Si≡). The dehydroxylated zeolite of Example 2 was characterized using FT-IR and solid-state NMR spectroscopy.

[0097] Figure 3 The FT-IR spectrum of the dehydroxylated zeolite from Example 2 is depicted. The FT-IR band corresponding to monomethylsilanol appears at 3743 cm⁻¹. - ¹, and 3627 cm - ¹ and 3563 cm - The two strong bands at ¹ belong to the high-frequency and low-frequency OH bridging groups. 3601 cm⁻¹ - The band at ¹ corresponds to a high-frequency group polarized by aluminum compounds outside the Lewis acid framework. 3680 cm⁻¹ - The weaker band at ¹ corresponds to an acidic Al-O(H)-Al group, which is partially attached to the framework of the dehydroxylated zeolite of Example 2.

[0098] Figure 4 The ¹H-MAS-NMR spectrum of the dehydroxylated zeolite of Example 2 is shown. The ¹H-MAS-NMR spectrum of the dehydroxylated zeolite of Example 2 shows a peak at 1.76 ppm belonging to an isolated silanol group (≡Si-OH), and two peaks at 4.51 ppm and 4.05 ppm belonging to Brønsted acid groups (≡Si-O(H)->Al≡).

[0099] Figure 5 The dehydroxylated zeolite of Example 2 is shown. 29 Si-CP-MAS-NMR spectrum. Dehydroxylated zeolite of Example 2. 29 Si-CP-MAS-NMR spectrum in A peak is shown at 106.57 ppm, corresponding to Si in tetrahedral coordination, representing the Si-O-Si network structure.

[0100] Figure 6 The dehydroxylated zeolite of Example 2 is shown. 27 Al-MAS-NMR spectrum. Dehydroxylated zeolite of Example 2. 27 The Al-MAS-NMR spectrum shows a broad resonance peak corresponding to four-coordinate, five-coordinate, and eight-coordinate aluminum centers, with the five-coordinate aluminum center being the dominant one (26.7 ppm).

[0101] Example 3 – Formation of Modified Zeolite The dehydroxylated zeolite of Example 2 was reacted with ammonia to form a modified zeolite. One gram of the dehydroxylated zeolite of Example 2 was added to a quartz reactor in a glove box. The reactor was evacuated under high vacuum before being connected to the ammonia reactor. N2 was introduced into the reactor to check for leaks. Then, ammonia (NH3) was introduced into the reactor. The reactor was heated to 500°C with an ammonia flow of 300 mL / min and held for 6 hours. After 6 hours, the ammonia flow was replaced with an N2 flow, and the reactor was cooled to room temperature. The reactor was evacuated under high vacuum overnight. The modified zeolite of Example 3 was analyzed using FT-IR spectroscopy and solid-state NMR spectroscopy.

[0102] Figure 7 The FT-IR spectra of the modified zeolite of Example 3 (spectrum 710) and the FT-IR spectra of the dehydroxylated zeolite of Example 2 (spectrum 720) are shown. Compared with the FT-IR spectrum of the dehydroxylated zeolite of Example 2, the FT-IR spectrum of the modified zeolite of Example 3 is at 3533 cm⁻¹. - ¹、3445 cm - ¹、3343 cm - ¹、3293 cm - ¹, 1623 cm - ¹ and 1554 cm - The ¹ section includes six new peaks, corresponding to ν. s (≡Si-NH2), ν as (≡Si-NH2), ν s (≡Si-NH2->Al≡), ν as (≡Si-NH2->Al≡), δ(≡Si-NH2->Al≡), and δ(≡Si-NH2).

[0103] Figure 8 The modified zeolite of Example 3 is shown. 1 1H-MAS-NMR spectrum. Modified zeolite of Example 3. 1 The H-MAS-NMR spectrum includes a peak at 0.64 ppm, corresponding to silylamine [ The peak at 2.15 ppm corresponds to the silylamine coordinated with aluminum (≡Si-NH2->Al≡); and the peak at 6.60 ppm corresponds to (≡Si-OH->Al≡). Due to the presence of different types of aluminum coordination, multiple peaks of silylamines coordinated with aluminum were observed.

[0104] Figure 9 The modified zeolite of Example 3 is shown. 29 Si-CP-MAS-NMR spectrum. The modified zeolite of Example 3.29 Si-CP-MAS-NMR spectra include The peak at 76 ppm corresponds to Q 2 SiO2(NH2)2 (Gen-silamide); The peak at 85 ppm corresponds to Q 3 SiO3NH2 (silylamine); The peak at 94 ppm corresponds to Q 2 SiO2(OH)2; The peak at 100 ppm corresponds to Q 3 SiO3(OH); and The peak at 105 ppm corresponds to Q 4 SiO4.

[0105] Figure 10 The modified zeolite of Example 3 is shown. 27 Al-MAS-NMR spectrum. Modified zeolite of Example 3. 27 The Al-MAS-NMR spectrum includes a broad peak corresponding to tetra-coordinate, penta-coordinate, and octa-coordinate aluminum centers, with the tetra-coordinate aluminum center being the dominant one (60 ppm).

[0106] The crystallinity of the dehydroxylated zeolite of Example 2 and the modified zeolite of Example 3 was analyzed using powder X-ray diffraction. Figure 11 XRD patterns of the dehydroxylated zeolite of Example 2 (Figure 1110) and the modified zeolite of Example 3 (Figure 1120) are shown. Comparison of the XRD patterns revealed no structural changes; the modified zeolite of Example 3 maintained its complete crystallinity. This was unexpected, as the harsh amination reaction conditions could lead to a loss of crystallinity. The modified zeolite of Example 3 exhibits cubic crystal symmetry with space group Fd-3m, a typical characteristic of the FAU framework. Furthermore, XRD studies of the modified zeolite of Example 3 showed that it was stable after ammonia treatment and did not contain any other impurity phases.

[0107] The N2 physical adsorption isotherms of the dehydroxylated zeolite of Example 2 and the modified zeolite of Example 3 were measured. Figure 12 The N2 physical adsorption isotherms (isotherm 1210) for the dehydroxylated zeolite of Example 2 and the N2 physical adsorption isotherms (isotherm 1220) for the modified zeolite of Example 3 are shown. The N2 physical adsorption isotherms exhibit the characteristics of Type I and Type IV isotherms for hierarchical pore structures. The BET surface area, pore volume, and pore size distribution of the dehydroxylated zeolite of Example 2 and the modified zeolite of Example 3 were also measured. Figure 12The illustrations show the pore size distribution of the dehydroxylated zeolite of Example 2 and the modified zeolite of Example 3. Table 2 shows the BET surface area, mesopore size, and pore volume of the dehydroxylated zeolite and the modified zeolite. As shown in Table 2, the BET surface area of ​​the modified zeolite is larger than that of the dehydroxylated zeolite. Increasing the pore volume, total surface area, and pore size of the modified zeolite can improve the contact between the reactants and the active sites on the modified zeolite, thereby improving catalytic performance.

[0108] Table 2

[0109] Figure 13 The FT-IR spectra of pyridine for the modified zeolite of Example 3 at three temperatures were depicted. Spectrum 1310 is the FT-IR spectrum of the modified zeolite of Example 3 at 150 °C, spectrum 1320 is the FT-IR spectrum of the modified zeolite of Example 3 at 250 °C, and spectrum 1330 is the FT-IR spectrum of the modified zeolite of Example 3 at 350 °C. The peak corresponding to Brønsted acidity is located at 1545 cm⁻¹. - ¹, using “B” "Marked; the peak corresponding to Lewis acidity is located at 1455 cm⁻¹" - ¹, marked with “L”. Note that, Figure 13 The middle is marked as "B" The Brønsted acid peak is a signal that overlaps with the signal of silane (Si-NH2). The total concentration of acid sites was quantified, and the values ​​are included in Table 3.

[0110] Table 3

[0111] The acidity properties of the mesoporous zeolite with cubic symmetry ordered arrangement in Example 1 and the dehydroxylated zeolite in Example 2 were measured by pyridine FT-IR spectroscopy at 150°C. The acidity properties of the mesoporous zeolite of Example 1, containing a cubic symmetry ordered arrangement of mesoporous structures, are shown in Table 4. The acidity properties of the dehydroxylated zeolite of Example 2 are shown in Table 5. As shown in Tables 3 and 5, the total acidity of the modified zeolite of Example 3 is slightly higher than that of the dehydroxylated zeolite of Example 2. The acidity of the modified zeolite can be adjusted to modify its catalytic performance.

[0112] Table 4

[0113] Table 5

[0114] Figure 14A and Figure 14B TEM micrographs of the dehydroxylated zeolite of Example 2 are depicted. Figure 15A and Figure 15B TEM micrographs of the modified zeolite from Example 3 are depicted. Figures 14A to 14B and Figures 15A to 15B As shown, the crystal structure and ordered mesoporous structure of the dehydroxylated zeolite of Example 2 were retained in the modified zeolite of Example 3 after amine modification treatment.

[0115] In a first aspect of this disclosure, a modified zeolite comprises: a microporous framework comprising a plurality of micropores with a diameter less than or equal to 2 nm, wherein the microporous framework comprises at least silicon atoms and oxygen atoms; a plurality of mesopores with a diameter greater than 2 nm and less than or equal to 50 nm, wherein the plurality of mesopores are arranged in a cubic symmetry order; wherein the modified zeolite comprises: an isolated terminal primary amine functional group bonded to silicon atoms of the microporous framework; or a silazane functional group, wherein the nitrogen atom of the silazane bridges two silicon atoms of the microporous framework; or both.

[0116] The second aspect of this disclosure may include the first aspect, wherein the modified zeolite comprises a Lewis acid portion and a Brønsted acid portion, and the ratio of the Lewis acid portion to the Brønsted acid portion is 6.2 to 7.9.

[0117] A third aspect of this disclosure may include either the first or second aspect, wherein the total acidity of the modified zeolite is from 100 µmol / g to 250 µmol / g.

[0118] The fourth aspect of this disclosure may include any one of the first to third aspects, wherein the modified zeolite comprises isolated terminal primary amine functional groups bonded to silicon atoms of the microporous framework.

[0119] The fifth aspect of this disclosure may include the fourth aspect, wherein the modified zeolite comprises 0.5 mmol / g to 3.0 mmol / g of isolated terminal primary amine functional groups.

[0120] The sixth aspect of this disclosure may include any one of the first to fifth aspects, wherein the modified zeolite comprises a silazane functional group, wherein the nitrogen atom of the silazane bridges two silicon atoms of the microporous framework.

[0121] The seventh aspect of this disclosure may include the sixth aspect, wherein the modified zeolite comprises 1.5 mmol / g to 3.0 mmol / g of silazane functional groups.

[0122] The eighth aspect of this disclosure may include any one of the first to seventh aspects, wherein the modified zeolite simultaneously comprises (a) an isolated terminal primary amine functional group bonded to silicon atoms of the microporous framework, and (b) a silazane functional group, wherein the nitrogen atom of the silazane bridges two silicon atoms of the microporous framework.

[0123] The ninth aspect of this disclosure may include any one of the first to eighth aspects, wherein the surface area of ​​the modified zeolite is 200 m². 2 / g to 1500 m 2 / g.

[0124] The tenth aspect of this disclosure may include any one of the first to ninth aspects, wherein the pore volume of the modified zeolite is 0.01 cm³. 3 / g to 1.5 cm 3 / g.

[0125] The eleventh aspect of this disclosure may include any one of the first to tenth aspects, wherein the mesopores are arranged in a cubic symmetry order, and their space group is Ia-3d, Fm-3m, Pm-3n, Pn-3m, Im-3m or Fd-3m.

[0126] The twelfth aspect of this disclosure may include any one of the first to eleventh aspects, wherein the modified zeolite is an FAU framework type zeolite.

[0127] The thirteenth aspect of this disclosure may include any one of the first to twelfth aspects, wherein the modified zeolite is USY zeolite.

[0128] The fourteenth aspect of this disclosure may include any one of the first to thirteenth aspects, wherein the microporous framework further comprises aluminum atoms, and the ratio of silicon atoms to aluminum atoms is 1.5 to 1500.

[0129] In a fifteenth aspect of this disclosure, a method for processing a hydrocarbon feedstock includes: contacting the hydrocarbon feedstock with a modified zeolite to form a product, wherein the modified zeolite comprises: a microporous framework comprising a plurality of micropores with a diameter less than or equal to 2 nm, wherein the microporous framework comprises at least silicon atoms and oxygen atoms; a plurality of mesopores with a diameter greater than 2 nm and less than or equal to 50 nm, wherein the plurality of mesopores are arranged in a cubic symmetry order; and wherein the modified zeolite comprises: an isolated terminal primary amine functional group bonded to silicon atoms of the microporous framework; or a silazane functional group, wherein the nitrogen atom of the silazane bridges two silicon atoms of the microporous framework; or both.

[0130] According to a sixteenth aspect of this disclosure, a method for preparing a modified zeolite includes: contacting a dehydroxylated zeolite with ammonia, wherein the dehydroxylated zeolite comprises: a microporous framework containing a plurality of micropores with a diameter less than or equal to 2 nm, wherein the microporous framework contains at least silicon atoms and oxygen atoms; a plurality of mesopores with a diameter greater than 2 nm and less than or equal to 50 nm, wherein the plurality of mesopores are arranged in a cubic symmetric order; and isolated terminal silanol functional groups containing hydroxyl groups bonded to silicon atoms of the microporous framework; wherein contacting the dehydroxylated zeolite with ammonia forms a modified zeolite.

[0131] The seventeenth aspect of this disclosure may include the sixteenth aspect, wherein the method further includes dehydroxylating an initial zeolite to form the dehydroxylated zeolite, wherein the initial zeolite primarily comprises an ortho-silanol functional group, and wherein dehydroxylating the initial zeolite forms the isolated terminal silanol functional group.

[0132] The eighteenth aspect of this disclosure may include the seventeenth aspect, wherein the dehydroxylation temperature is 800°C or lower; the dehydroxylated zeolite is contacted with ammonia at a temperature below 800°C; and the modified zeolite comprises isolated terminal primary amine functional groups bonded to silicon atoms of the microporous framework.

[0133] The nineteenth aspect of this disclosure may include the seventeenth aspect, wherein the dehydroxylation temperature is 800°C or higher; the dehydroxylated zeolite is contacted with ammonia at a temperature of 600°C or higher; and the modified zeolite comprises a silazane functional group, wherein the nitrogen atom of the silazane bridges two silicon atoms of the microporous framework.

[0134] The twentieth aspect of this disclosure may include the seventeenth aspect, wherein the dehydroxylation temperature is from 650°C to 1100°C, and wherein the dehydroxylation zeolite is contacted with ammonia at a temperature below 900°C.

[0135] The subject matter of this disclosure has been described in detail with reference to specific embodiments. It should be understood that any detailed description of a feature in an embodiment does not necessarily mean that the feature is essential to that particular embodiment or any other embodiment. Furthermore, it will be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter.

[0136] For the purposes of describing and defining this disclosure, it should be noted that the terms “about” or “approximately” are used in this disclosure to reflect the degree of uncertainty that may be inherent in any quantitative comparison, numerical value, measurement, or other representation. In this disclosure, the terms “about” and / or “approximately” are also used to indicate the degree of deviation that may exist between a quantitative representation and the reference value, without altering the essential function of the subject matter.

[0137] It should be understood that any two quantitative values ​​assigned to an attribute can constitute a range of that attribute, and this disclosure covers the combination of ranges formed by all the stated quantitative values ​​of that attribute.

[0138] It should be noted that one or more of the following claims use the term "wherein" as a transitional phrase. For the purposes of defining this technology, it should be noted that this term is introduced in the claims as an open-ended transitional phrase to introduce a description of a series of structural features, and should be interpreted in a manner similar to the more commonly used open-ended preamble term "comprising." It should be understood that in the case of describing a first component as "comprising" a second component, it is contemplated that in some embodiments, the first component "consists of" or "substantially consists of" the second component. The transitional phrase "consists of..." excludes any element, step, or ingredient not specified in the claims, while the transitional phrase "substantially consists of..." limits the scope to the specified materials or steps and those that do not substantially affect the basic and novel characteristics of the claimed embodiment.

Claims

1. Modified zeolite, comprising: A microporous framework comprising multiple micropores with a diameter less than or equal to 2 nm, wherein the microporous framework comprises at least silicon atoms and oxygen atoms; Multiple mesopores with a diameter greater than 2 nm and less than or equal to 50 nm, wherein the multiple mesopores are arranged in a cubic symmetric order; and The modified zeolite comprises: Isolated terminal primary amine functional groups bonded to silicon atoms in the microporous framework; or A silazane functional group, wherein the nitrogen atom of the silazane bridges two silicon atoms of the microporous framework; or It has both.

2. The modified zeolite according to claim 1, wherein the modified zeolite comprises a Lewis acid portion and a Brønsted acid portion, and the ratio of the Lewis acid portion to the Brønsted acid portion is 6.2 to 7.

9.

3. The modified zeolite according to claim 1 or 2, wherein the total acidity of the modified zeolite is from 100 µmol / g to 250 µmol / g.

4. The modified zeolite according to any one of claims 1 to 3, wherein the modified zeolite comprises isolated terminal primary amine functional groups bonded to silicon atoms of the microporous framework, and optionally, wherein the modified zeolite comprises 0.5 mmol / g to 3.0 mmol / g of isolated terminal primary amine functional groups.

5. The modified zeolite according to any one of claims 1 to 4, wherein the modified zeolite comprises a silazane functional group, wherein the nitrogen atom of the silazane bridges two silicon atoms of the microporous framework, and optionally, wherein the modified zeolite comprises 1.5 mmol / g to 3.0 mmol / g of the silazane functional group.

6. The modified zeolite according to any one of claims 1 to 5, wherein the modified zeolite simultaneously comprises (a) an isolated terminal primary amine functional group bonded to silicon atoms of the microporous framework, and (b) a silazane functional group, wherein the nitrogen atom of the silazane bridges two silicon atoms of the microporous framework.

7. The modified zeolite according to any one of claims 1 to 6, wherein at least one of the following conditions is met: The modified zeolite has a surface area of ​​200 m². 2 / g to 1500 m 2 / g; The modified zeolite has a pore volume of 0.01 cm³. 3 / g to 1.5 cm 3 / g.

8. The modified zeolite according to any one of claims 1 to 7, wherein the mesopores are arranged in a cubic symmetry order, and their space group is Ia-3d, Fm-3m, Pm-3n, Pn-3m, Im-3m or Fd-3m.

9. The modified zeolite according to any one of claims 1 to 8, wherein the modified zeolite is an FAU framework type zeolite or a USY zeolite.

10. The modified zeolite according to any one of claims 1 to 9, wherein the microporous framework further comprises aluminum atoms, and the ratio of silicon atoms to aluminum atoms is 1.5 to 1500.

11. A method for processing a hydrocarbon feedstock, the method comprising contacting the hydrocarbon feedstock with a modified zeolite to form a product, wherein the modified zeolite comprises: A microporous framework comprising multiple micropores with a diameter less than or equal to 2 nm, wherein the microporous framework comprises at least silicon atoms and oxygen atoms; Multiple mesopores with a diameter greater than 2 nm and less than or equal to 50 nm, wherein the multiple mesopores are arranged in a cubic symmetric order; The modified zeolite comprises: Isolated terminal primary amine functional groups bonded to silicon atoms in the microporous framework; or The functional group of silazane, wherein the nitrogen atom of silazane bridges two silicon atoms of the microporous framework; or It has both.

12. A method for preparing modified zeolite, the method comprising: The dehydroxylated zeolite is contacted with ammonia, wherein the dehydroxylated zeolite comprises: A microporous framework comprising multiple micropores with a diameter less than or equal to 2 nm, wherein the microporous framework comprises at least silicon atoms and oxygen atoms; Multiple mesopores with a diameter greater than 2 nm and less than or equal to 50 nm, wherein the multiple mesopores are arranged in a cubic symmetric order; and Isolated terminal silanol functional groups containing hydroxyl groups bonded to the silicon atoms of the microporous framework; The modified zeolite is formed by contacting the dehydroxylated zeolite with the ammonia.

13. The method of claim 12, further comprising dehydroxylating an initial zeolite to form the dehydroxylated zeolite, wherein the initial zeolite primarily comprises an ortho-silanol functional group, and wherein dehydroxylating the initial zeolite forms the isolated terminal silanol functional group.

14. The method of claim 13, wherein: The dehydroxylation temperature is 800°C or lower; The dehydroxylated zeolite is contacted with ammonia at a temperature below 800°C; and The modified zeolite contains isolated terminal primary amine functional groups bonded to silicon atoms in the microporous framework.

15. The method according to claim 13, wherein: The dehydroxylation temperature is 800°C or higher; The dehydroxylated zeolite is contacted with ammonia at a temperature of 600°C or higher; and The modified zeolite contains silazane functional groups, wherein the nitrogen atom of the silazane bridges two silicon atoms of the microporous framework.

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