Zeolite with four-coordinated Lewis aluminum sites and method for preparing the same

Abstract

The modified crystalline zeolite material has a zeolite framework having both a four-coordinated Lewis aluminum unit site and a Bronsted aluminum site. The four-coordinated Lewis aluminum unit site includes an aluminum atom covalently bonded to a variable group and two oxygen atoms and further coordinated to a third oxygen atom. The variable group can be an alkyl, a hydrogen group, or a hydroxyl group. A method for incorporating a four-coordinated Lewis aluminum unit site into a crystalline zeolite material includes contacting the crystalline zeolite material with a dialkyl aluminum hydride, which reacts with the zeolite framework and forms a four-coordinated alkyl aluminum unit site. Heating this product causes the β-hydrogen of the alkyl to be eliminated, forming a four-coordinated aluminum hydride unit site. After further oxidation, at least a portion of the four-coordinated aluminum hydride unit site is converted into a four-coordinated aluminum hydroxide unit site.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. application No. 17 / 015,653, filed on September 9, 2020, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present application relates generally to modified zeolites and methods for modifying zeolites, and more particularly to zeolites including tetracoordinated Lewis acidic aluminum unit sites and methods for preparing the zeolites. Background Art

[0004] Zeolite has a wide range of uses in many different industries. For example, in the petroleum industry, zeolite catalysts can be included in processes such as fluid catalytic cracking (FCC) and hydrocracking to catalyze reactions such as hydrogenation, dehydrogenation, isomerization, alkylation and cracking. These methods each continue to need to develop zeolites with unit sites, with the goal of increasing activity and increasing shape selectivity such as controllably and predictably. Better understanding of the active sites in zeolites can be beneficial for finding catalyst materials that have high selectivity to catalyzing a single chemical reaction than to other chemical reactions, thereby preferably the desired product of the selected reaction. Still need a zeolite with the following structure, the structure has highly determined active sites in terms of quantity, structure and performance. Summary of the invention

[0005] Against the above background, exemplary embodiments of the present disclosure relate to a modified crystalline zeolite material having a zeolite framework. The zeolite framework includes a tetracoordinated Lewis aluminum site and a Bronsted aluminum ( The four-coordinate Lewis aluminum unit site has an environment in the zeolite framework according to the structure (AI):

[0006]

[0007] In the structure (AI): each R is independently selected from the group consisting of an alkyl group, a hydrogen group, and a hydroxyl group; and each Si Q is a silicon atom of the zeolite framework and is bonded to four oxygen atoms. The Brønsted aluminum site has an environment in the zeolite framework according to structure (A-II):

[0008]

[0009] In the structure (A-II), each Si Q It is the silicon atom of the zeolite framework and is bonded to four oxygen atoms.

[0010] Other exemplary embodiments of the present disclosure relate to methods for incorporating tetracoordinate Lewis aluminum unit sites into a crystalline zeolite material having a zeolite framework comprising Bronsted aluminum sites. The method comprises contacting the crystalline zeolite material with a dialkylaluminum hydride of empirical formula R2AlH, wherein each R is an alkyl group, so that the dialkylaluminum hydride reacts with the zeolite framework and forms tetracoordinate alkylaluminum sites having an environment in the zeolite framework according to structure (BI):

[0011]

[0012] In structure (BI), each Si Q is the silicon atom of the zeolite framework and is bonded to four oxygen atoms. The process forms a modified crystalline zeolite material, namely an alkylaluminum zeolite.

[0013] In some embodiments, the method for incorporating a tetracoordinated Lewis aluminum unit site into a crystalline zeolite material further comprises heating the alkyl aluminum zeolite to cause β-hydrogen elimination of at least a portion of the alkyl groups R, thereby forming a tetracoordinated aluminum hydride unit site in the zeolite framework having an environment according to structure (BI), wherein R is a hydrogen group.

[0014] In some embodiments, the method for incorporating tetracoordinated Lewis aluminum unit sites into a crystalline zeolite material further comprises oxidizing the aluminum hydride zeolite to convert at least a portion of the tetracoordinated aluminum hydride unit sites into tetracoordinated aluminum hydroxide sites having an environment in the zeolite framework according to structure (BI), wherein R is a hydroxyl group.

[0015] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims.

[0016] Other features and advantages of the embodiments described herein will be set forth in the following detailed description, and in part will become apparent to those skilled in the art from that description or through practice of the embodiments described herein, including the following detailed description, claims, and accompanying drawings.

[0017] It should be understood that both the above general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein and together with the description serve to explain the principles and operation of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the energy dispersive X-ray (EDX) spectrum of FH-ZSM-5 zeolite before dehydroxylation.

[0019] Figures 2A-2D is a micrograph of FH-ZSM-5 zeolite before dehydroxylation obtained by transmission electron microscopy (TEM).

[0020] Figure 3 An exemplary dehydroxylation reaction of a portion of an aluminosilicate zeolite is illustrated.

[0021] Figure 4 is the EDX spectrum of H-ZSM-5 zeolite after dehydroxylation.

[0022] Figure 5 It is the selected area electron diffraction (SAED) pattern of H-ZSM-5 zeolite after dehydroxylation.

[0023] Figures 6A-6D is a micrograph of H-ZSM-5 zeolite before dehydroxylation obtained by TEM.

[0024] Figure 7 is an exemplary alkylation reaction of a dehydroxylated aluminosilicate zeolite.

[0025] Figure 8 is the EDX spectrum of the alkylaluminum zeolite prepared by the reaction of dehydroxylated H-ZSM-5 with diisobutylaluminum (DIBAL).

[0026] Fig. 9 is the SAED pattern of alkylaluminum zeolite prepared by reacting dehydroxylated H-ZSM-5 with DIBAL.

[0027] Fig. 10A and 10B is a micrograph obtained by TEM of an alkylaluminum zeolite prepared by reaction of dehydroxylated H-ZSM-5 with DIBAL.

[0028] Fig.11 Shown are superimposed Fourier transform infrared (FTIR) spectra of: (i) H-ZSM-5 zeolite after dehydroxylation; and (ii) alkylaluminum zeolite prepared by reacting dehydroxylated H-ZSM-5 with DIBAL.

[0029] Fig.12 is an exemplary beta-elimination reaction to form aluminum hydride zeolite by thermally treating an aluminum alkyl zeolite.

[0030] Fig.13 is the EDX spectrum of aluminum hydride zeolite prepared by heat treating alkyl aluminum zeolite.

[0031] Fig.14is the SAED pattern of aluminum hydride zeolite prepared by heat treating alkyl aluminum zeolite.

[0032] Figures 15A-15D is a micrograph obtained by TEM of an aluminum hydride zeolite prepared by heat treating an alkyl aluminum zeolite.

[0033] Fig.16 Shown are superimposed Fourier transform infrared (FTIR) spectra of: (i) an alkylaluminum zeolite prepared by reacting dehydroxylated H-ZSM-5 with DIBAL; and (ii) an aluminum hydride zeolite prepared by thermally treating the alkylaluminum zeolite.

[0034] Fig.17 is an exemplary reaction for forming aluminum hydroxide zeolite by oxidation of aluminum hydride zeolite.

[0035] Fig.18 is the EDX spectrum of aluminum hydroxide zeolite prepared by oxidizing aluminum hydride zeolite.

[0036] Fig.19 is the SAED pattern of aluminum hydroxide zeolite prepared by oxidizing aluminum hydride zeolite.

[0037] Figures 20A-20D is a micrograph obtained by TEM of an aluminum hydroxide zeolite prepared by oxidation of aluminum hydride zeolite.

[0038] Fig.21 is the FTIR spectrum of aluminum hydroxide zeolite prepared by oxidation of aluminum hydride zeolite.

[0039] Fig. 22 The following overlay is shown 27 Al solid state NMR ( 27 Al SS-NMR) spectra of: (i) alkylaluminum zeolite prepared by reacting dehydroxylated H-ZSM-5 with DIBAL; (ii) aluminum hydride zeolite prepared by heat treating alkylaluminum zeolite; and (iii) aluminum hydroxide zeolite prepared by oxidizing aluminum hydride zeolite.

[0040] Fig.23 The following superposition protons are shown ( 1 H) SS-NMR spectra of: (i) alkylaluminum zeolite prepared by reacting dehydroxylated H-ZSM-5 with DIBAL; (ii) aluminum hydride zeolite prepared by heat treating alkylaluminum zeolite; and (iii) aluminum hydroxide zeolite prepared by oxidizing aluminum hydride zeolite. DETAILED DESCRIPTION

[0041] As used herein, the conventional triple bond symbol "≡", as used in "≡X", where X is any element in the periodic table, refers to three associations of one atom of element X with a corresponding one of three independent oxygen atoms. These associations may include covalent single bonds, coordinate coordination, or a combination thereof. Typically, in the case of a tetracoordinate aluminum unit site of the zeolite of the present disclosure, the three associations may include two covalent single bonds (one of the two oxygen atoms to the other) and one coordination of an atom of element X to a third oxygen atom. Thus, for example, "[≡Al-R]" refers to an aluminum atom that is covalently bonded to two oxygen atoms, coordinated to a third oxygen atom (e.g., an oxygen atom of a siloxane bridge), and also covalently bonded to a group R, where R is, for example, an alkyl group, a hydrogen atom, or a hydroxyl group. Consistent with this definition, the tetracoordinate aluminum single substance "[≡Al-R]" in the case of the zeolite according to the embodiment can be considered to be an abbreviated form of the structural symbol [(≡Si-O-Si≡)(≡Si-O)2Al-R]. In this notation, the silicon atoms in the moiety [≡Si—O] are each covalently bonded to four oxygen atoms.

[0042] In some embodiments of the present disclosure, modified crystalline zeolite materials are described that include well-defined aluminum Lewis acid unit sites that can be used as anchor sites for immobilizing catalytically active metals. The aluminum Lewis acid unit sites provide the opportunity to control the acidity of the zeolite support and facilitate obtaining higher conversions and efficiencies than can be obtained with zeolites that do not include well-defined aluminum Lewis acid unit sites.

[0043] In other embodiments, methods for preparing modified crystalline zeolite materials with well-defined aluminum Lewis acid unit sites are described. Due to the large-scale application of acid zeolites in industrial environments, considerable efforts have been invested to control the number and intensity of zeolite acid sites in order to optimize catalyst design. The method disclosed herein is conducive to improving the control level of zeolite acidity by carefully designing acid sites. In particular, [≡Al-alkyl], [≡Al-H] and [≡Al-OH] substances are examples of well-defined anchor sites of any active metal (such as platinum, nickel, cobalt, palladium, molybdenum, titanium, zirconium and hafnium). Each of [≡Al-alkyl], [≡Al-H] and [≡Al-OH] substances is significant for zeolite materials because they include aluminum atoms in an unusual four-coordinate environment within the zeolite framework. The four-coordinate aluminum sites [≡Al-alkyl], [≡Al-H] and [≡Al-OH] cannot be prepared in a controlled manner by conventional strategies. It should be understood that in such a tetracoordinated aluminum site, the aluminum atom retains a valence of three even though coordination with an oxygen atom increases the coordination number of the aluminum atom.

[0044] The aluminosilicate zeolite framework consists of tetrahedral sites (T sites) occupied by silicon atoms connected by bridging oxygen atoms. When a silicon atom is replaced by aluminum, a negative charge is imparted to the zeolite framework and shared between the four bridging oxygen atoms, which is balanced by Bronsted acidic protons or extralattice cationic sites or complexes. Bronsted acidic protons are based on the well-known Bronsted-Lowry definition of acids ( -Lowry definition) where, as a basic concept, when an acid HA and a base B react with each other, the acid forms its conjugate base X by exchanging protons. - , and the base forms its conjugate acid HB + In the case of Brønsted aluminum sites in zeolites, the acidic species can be represented by ≡Al - -O + (H)-Si≡ represents. For example, by interacting with a base such as sodium hydroxide (NaOH), a conjugate base ≡Al can be formed. - -O + (Na)-Si≡ and water molecules (OH - conjugate acid).

[0045] The modified crystalline zeolite material according to the embodiment of the present application and the modified crystalline zeolite material prepared according to the method of the present application include modified four-coordinated Lewis aluminum unit sites, conventional Bronsted aluminum sites and conventional Lewis aluminum sites. The characteristics of the Lewis aluminum sites are consistent with the Lewis acidity theory, in which Lewis acids are defined as chemical substances containing empty orbitals that can accept electron pairs from Lewis bases to form Lewis adducts. In contrast, Lewis bases are any substances with filled orbitals containing electron pairs that do not participate in bonding, but can form coordinate bonds with Lewis acids to form Lewis adducts.

[0046] In the case of the modified tetracoordinated Lewis aluminum unit point in the modified crystalline zeolite material according to the embodiment, it should be understood that the aluminum atom in the electrically neutral state includes three valence electrons. Even so, in the zeolite framework, the aluminum atom that has been bonded to three other atoms can be shown as a Lewis acid in some cases described in the present disclosure, which accepts lone pair electron density from Lewis basic oxygen atoms, thereby forming an adduct between aluminum atoms and oxygen atoms. The result of this adduct formation is covalent bonding to three original substituents, while coordinate bonding to the fourth substituent, i.e., the tetracoordinated aluminum atom on the electron-donating oxygen atom. It should be understood that in the drawings and images of the present application, covalent bonds are represented by conventional lines between atoms, and coordinate bonds are represented by arrows drawn from electron donors (Lewis bases) to electron acceptors (Lewis acids).

[0047] Embodiments of modified crystalline zeolite materials comprising a tetracoordinated Lewis aluminum unit site will now be discussed in detail. Embodiments of methods for incorporating a tetracoordinated Lewis aluminum unit site into a crystalline zeolite material to form a modified crystalline zeolite material will then be described.

[0048] The modified crystalline zeolite material according to an embodiment of the present disclosure has a zeolite framework including a tetracoordinated Lewis aluminum unit site and a Bronsted aluminum site incorporated into the zeolite framework. The tetracoordinated Lewis aluminum site has an environment in the zeolite framework according to the structure (AI):

[0049]

[0050] In structure (AI), each R is independently selected from the group consisting of an alkyl group, a hydrogen group, and a hydroxyl group. Q is a silicon atom of the zeolite framework, which is bonded to four oxygen atoms. The Brønsted aluminum site has an environment in the zeolite framework according to structure (A-II):

[0051]

[0052] Similarly, in structure (A-II), each Si Q It is the silicon atom of the zeolite framework, which is bonded to four oxygen atoms.

[0053] In an embodiment of a modified crystalline zeolite material, the modified crystalline zeolite material can be any zeolite including Bronsted aluminum sites and sites reactive to dialkylaluminum hydrides other than Bronsted aluminum sites. In this regard, "zeolite" includes a crystalline material having a framework consisting of aluminum, silicon and oxygen and having optional substitution or replacement. Zeolites include aluminosilicates having a three-dimensional framework and molecular-sized pores. Certain zeolite materials are ordered porous crystalline aluminosilicates having a well-defined crystalline structure determined by X-ray diffraction, in which a large number of smaller cavities are present, which can be interconnected by many smaller channels or windows. In a particular zeolite material, the size of these cavities and pores is uniform. Because the size of these pores makes it possible to accept adsorbed molecules of certain sizes and reject adsorbed molecules of larger sizes, these materials are referred to as "molecular sieves" and are used in various ways to utilize these properties. According to an embodiment, the term "zeolite" with respect to a crystalline zeolite material may further include any member of the group of structured aluminosilicate minerals including cations such as sodium, calcium, barium, beryllium, lithium, potassium, magnesium, strontium, or combinations thereof, generally conforming to the nominal formula H x Al x Si 1-x O2, where H can be replaced by any other monovalent cation or (when x associated with H is divisible by the valence) a multivalent cation.

[0054] The term "zeolite" with respect to the modified crystalline zeolite material of the embodiments further includes "zeolite-related materials" or "zeolite-type materials" which are modified by replacing Si with other elements. 4+ or Al 3+ Preparation, as in the case of aluminophosphates (eg MeAPO, SAPO, EIAPO, MeAPSO and EIAPSO), gallophosphates, zincphosphates and titanosilicates.

[0055] The crystalline zeolite material modified according to the embodiment may include any of the following crystalline porous materials, which have a framework according to the structure type defined by the International Zeolite Association as described in the Zeolite Framework Types database of the IZA structure commission, such as ABW, ACO, AEI, AEL, AEN, AET, AFG AFI, AFN, AFO, AFR, AFS, AFT, AFX, AFY, AHT, ANA, APC, APD, AST, ASV, ATN, ATO, ATS, ATT, ATV, AWO, AWW, BCT, *BEA, BEC, BIK, BOG, BPH, BRE, CAN, CAS, CDO, CFI, CGF, CGS, CHA, CHI, CLO, CON, CZP, DAC, DDR, DFO, DFT , DOH, DON, EAB, EDI, EMT, EON, EPI, ERI, ESV, ETR, EUO, EZT, FAR, FAU, FER, FRA, GIS, GIU, GME, GON, GOO, H EU, IFR, IHW, IMF, ISV, ITE, ITH, ITW, IWR, IWV, IWW, JBW, KFI, LAU, LEV, LIO, LIT, LOS, LOV, LTA, LTL, LTN , MAR, MAZ, MEI, MEL, MEP, MER, MFI, MFS, MON, MOR, MOZ, MSE, MSO, MTF, MTN, MTT, MTW, MWW, NAB, NAT, NES, N ON, NPO, NSI, OBW, OFF, OSI, OSO, OWE, PAR, PAU, PHI, PON, RHO, RON, RRO, RSN, RTE, RTH, RUT, RWR, RWY, SAO , SAS, SAT, SAV, SBE, SBN, SBS, SBT, SFE, SFF, SFG, SFH, SFN, SFO, SGT, SIV, SOD, SOS, SSF, SSY, STF, STI, STO, STT, SZR, TER, THO, TOL, TON, TSC, TUN, UEI, UFI, UOZ, USI, UTL, VET, VFI, VNI, VSV, WEI, WEN, YUG and ZON. According to an embodiment, the crystalline zeolite material may include an intergrown zeolite, wherein the crystalline zeolite material includes at least two independent intergrown zeolite portions within a single zeolite crystal, and the intergrown zeolite portions include zeolite portions of at least two different framework types, each framework type being selected from the aforementioned framework types.

[0056] The crystalline zeolite material modified according to the embodiment can be microporous, mesoporous, macroporous, or can have any one, two or three kinds of multiple pore sizes selected from micropore, mesopore and macropore, including an pore size less than 2nm or greater than 50nm in any case.Usually, porous substances are divided by pore size.For example, the material with an pore size less than 2 nanometers is classified as a microporous substance, the material with an pore size between 2nm and 50nm is classified as a mesoporous substance, and the material with an pore size greater than 50nm is classified as a macroporous substance.It should be understood that non-zeolite mesoporous silica, such as MCM-41 and SBA-15, can show significant microporosity.However, the microporosity of this type is disordered and not clearly defined, and should not be considered as the microporosity of zeolite.It should be understood that the terms "crystalline zeolite material" and "zeolite" in the present disclosure do not cover any type of mesoporous silica.

[0057] In exemplary embodiments, the modified crystalline zeolite material can be a modified form of a zeolite, such as an aluminosilicate zeolite, an aluminophosphate zeolite, a metal-substituted aluminophosphate (MeAPO) zeolite, and a silicoaluminophosphate (SAPO) zeolite, any of which has a tetracoordinated Lewis aluminum unit site added thereto. In some embodiments, the modified crystalline zeolite material is an aluminosilicate zeolite including a Bronsted aluminum site, wherein a tetracoordinated Lewis aluminum unit site is added thereto.

[0058] In a more specific exemplary embodiment, the modified crystalline zeolite material can be a modified form of an aluminosilicate zeolite having an MFI framework, such as ZSM-5 or acidic H-ZSM-5, to which a tetracoordinated Lewis aluminum unit site is added. Any of the foregoing examples of modified crystalline zeolite materials can contain other elements within the zeolite framework or as extra-framework material, provided that the modified crystalline zeolite material includes a Bronsted aluminum site according to structure (A-II) and a tetracoordinated Lewis aluminum unit site according to structure (AI). Examples of other elements that may be included in the modified crystalline zeolite material include, but are not limited to, antimony, arsenic, barium, beryllium, bismuth, boron, calcium, cerium, chromium, cobalt, copper, erbium, europium, gallium, germanium, gold, hafnium, indium, iridium, iron, lanthanum, lithium, magnesium, manganese, molybdenum, neodymium, nickel, niobium, osmium, palladium, phosphorus, platinum, praseodymium, rhodium, rhenium, ruthenium, silver, scandium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, yttrium, zinc, zirconium, extra-framework aluminum, and extra-framework silicon.

[0059] ZSM-5 zeolite is an aluminosilicate zeolite of MFI framework and belongs to the pentasil family of zeolites. ZSM-5 zeolite belongs to the orthorhombic space group Pnma, and its ideal unit cell parameters are a = 20.1 Angstrom (2.01 nanometers), b = 19.7 Angstrom (1.97nm), and c = 13.1 Angstrom (1.31 nanometers). ZSM-5 has Na n Al n Si96-n O 192 · A nominal chemical formula of 16H2O, wherein the subscript n is 0 to 27. Cations such as sodium or protons counteract the charge imbalance caused by the replacement of silicon with aluminum in the zeolite. An acidified form of ZSM-5 zeolite, in which a large number of acidic protons balance the charge, may be referred to as H-ZSM-5. The subscript n in ZSM-5 refers to the silicon-to-aluminum ratio (SAR) of the zeolite. Unless expressly stated to the contrary, embodiments of the present disclosure that include ZSM-5 zeolite are in no way limited to the SAR of ZSM-5 zeolite or any other zeolite that includes silica and alumina.

[0060] The modified crystalline zeolite material according to the embodiment is both zeolite and crystallization.Crystallized zeolite material is significantly different from amorphous materials such as mesoporous silica, in which composition SBA-15 is a well-known example.Mesoporous silica is an amorphous material with a pore size of 2nm to 50nm and low hydrothermal stability and acidity.Due to the amorphous nature of mesoporous silica, the x-ray diffraction pattern of such compositions usually contains very few peaks, and almost all peaks appear at less than 5 degrees 2θ.On the contrary, the crystalline zeolite material can contain different pore sizes in a single zeolite, including micropores less than 2nm in size, mesopores of 2nm to 50nm in size, macropores greater than 50nm in size, and any combination of two or three pore types selected from micropores, mesopores and macropores.Crystallized zeolite has high thermal stability and high acidity.Due to the crystallinity of zeolite, the x-ray diffraction pattern of the material usually includes many strong peaks, usually at an angle greater than 5 degrees 2θ.

[0061] About composition, compared with crystalline zeolite, mesoporous silica such as SBA-15 includes a very large number of silanol groups and partially condensed frameworks. The number of hydroxyl groups present in mesoporous silica can be changed by known preparation techniques. These composition characteristics of mesoporous silica are conducive to adding Lewis aluminum sites to mesoporous silica under fairly simple reaction conditions, thereby making it possible to anchor active metals to mesoporous silica. On the other hand, as recognized in the embodiments of this specification, the modification of crystalline zeolite structures such as ZSM-5 to include, for example, Lewis aluminum sites must be carried out under more challenging vacuum thermal conditions, because the aluminum atoms in the crystalline tetrahedral framework are very easy to come out of the zeolite framework with the removal of water. With respect to the formation of framework aluminum sites, and of course also with respect to the formation of framework Lewis aluminum sites, the aluminum atoms lost from the framework in this way strongly tend to form framework extracellular substances. In addition, the crystalline structure of zeolites with strong siloxane bonds and high hydrophilicity has challenged the modification of framework aluminum, which is not encountered in the aluminum modification of compositions such as mesoporous silica.

[0062] In some embodiments, the modified crystalline zeolite material is an alkylaluminum zeolite comprising a tetracoordinated Lewis aluminum unit site of structure (AI), wherein the groups R of at least a portion of the tetracoordinated Lewis aluminum unit sites of structure (AI) are alkyl groups, such as but not limited to (C1-C 20 In some embodiments, the modified crystalline zeolite material comprises a four-coordinated Lewis aluminum unit site of structure (AI), wherein the groups R of all four-coordinated Lewis aluminum unit sites of structure (AI) are alkyl groups.

[0063] As used with respect to the group R of the Lewis aluminum unit site of structure (AI), the term "alkyl" is understood in its broadest sense to refer to a saturated hydrocarbon group, which is straight or branched, including only carbon atoms and hydrogen atoms, and including, for example, 1 to 50 carbon atoms, 1 to 40 carbon atoms, 1 to 30 carbon atoms, 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to 5 carbon atoms, 1 to 4 carbon atoms, 3 to 10 carbon atoms, 4 to 10 carbon atoms or 3 to 5 carbon atoms. In some embodiments, the group R can be selected from the alkyl of the stable monomer dialkyl aluminum hydride compound capable of forming the formula R2AlH. Non-limiting examples of stable monomer dialkyl aluminum hydride compounds of formula R2AlH include those compounds disclosed in U.S. Patents 4,170,604 and 3,015,669. In a specific non-limiting embodiment, the group R of the Lewis aluminum unit site of structure (AI) in the modified crystalline zeolite material can be an isobutyl group.

[0064] Specific examples of straight chain alkyl groups of group R include, but are not limited to, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl. Examples of branched chain alkyl groups of group R include the formula -CH2CR 1 R 2 R 3 A group in which R 1 , R 2 and R 3 are independently (C1-C5)alkyl or hydrogen, provided that R 1 , R 2 and R 3 At least one of the R groups is a (C1-C5) alkyl group. Non-limiting examples of these groups include 2,2-dimethylpropyl (neopentyl) and 3,3-dimethylbutyl (neohexyl). Other examples of branched alkyl groups of the group R include the formula -CH(R 1 )-CH(R 2 )(R 3 ) group, wherein R 1 and R 2 One of them is hydrogen, and R 1 and R 2 The other is a straight chain or branched chain (C4-C15 ) alkyl, and R 3 Is a straight chain or branched chain (C4-C 15 Non-limiting examples of such groups include 1-methylpropyl (sec-butyl), 2-methylpropyl (isobutyl), 1-methylbutyl (sec-pentyl), 2-methylbutyl, 1-methylpentyl, and 2-methylpentyl.

[0065] In some embodiments, the modified crystalline zeolite material is an aluminum hydride zeolite comprising a four-coordinated Lewis aluminum unit site of structure (AI), wherein the groups R of at least a portion of the four-coordinated Lewis aluminum unit sites of structure (AI) are hydrogen groups (—H). In some embodiments, the modified crystalline zeolite material comprises a four-coordinated Lewis aluminum unit site of structure (AI), wherein the groups R of all four-coordinated Lewis aluminum unit sites of structure (AI) are hydrogen groups.

[0066] In some embodiments, the modified crystalline zeolite material is a hydroxyaluminum zeolite comprising a four-coordinated Lewis aluminum unit site of structure (AI), wherein the groups R of at least a portion of the four-coordinated Lewis aluminum unit sites of structure (AI) are hydroxyl groups (-OH). In some embodiments, the modified crystalline zeolite material comprises a four-coordinated Lewis aluminum unit site of structure (AI), wherein the groups R of all four-coordinated Lewis aluminum unit sites of structure (AI) are hydroxyl groups.

[0067] In some embodiments, the modified crystalline zeolite material comprises a four-coordinate Lewis aluminum unit site of structure (AI), wherein the group R can have different identities at different four-coordinate Lewis aluminum unit sites of structure (AI). In some embodiments, the modified crystalline zeolite material comprises a four-coordinate Lewis aluminum unit site of the modified crystalline zeolite material, wherein the four-coordinate Lewis aluminum unit sites comprise at least two of (a), (b), and (c): (a) a four-coordinate Lewis aluminum unit site having an environment according to structure (AI) in the zeolite framework, wherein R is an alkyl group; (b) a four-coordinate Lewis aluminum unit site having an environment according to structure (AI) in the zeolite framework, wherein R is a hydrogen group; and (c) a four-coordinate Lewis aluminum unit site having an environment according to structure (AI) in the zeolite framework, wherein R is a hydroxyl group.

[0068] In some embodiments, the modified crystalline zeolite material comprises a four-coordinated Lewis aluminum single site of structure (AI), wherein the groups R of some of the four-coordinated Lewis aluminum single sites of structure (AI) are alkyl groups, and the groups R of other four-coordinated Lewis aluminum single sites of structure (AI) are hydrogen groups. In some embodiments, the modified crystalline zeolite material comprises a four-coordinated Lewis aluminum single site of structure (AI), wherein the groups R of some of the four-coordinated Lewis aluminum single sites of structure (AI) are alkyl groups, and the groups R of other four-coordinated Lewis aluminum single sites of structure (AI) are hydroxyl groups. In some embodiments, the modified crystalline zeolite material comprises a four-coordinated Lewis aluminum single site of structure (AI), wherein the groups R of some of the four-coordinated Lewis aluminum single sites of structure (AI) are hydrogen groups, and the groups R of other four-coordinated Lewis aluminum single sites of structure (AI) are hydroxyl groups. In some embodiments, the modified crystalline zeolite material includes a four-coordinated Lewis aluminum unit site of structure (AI), wherein the groups R of some of the four-coordinated Lewis aluminum unit sites of structure (AI) are alkyl groups, the groups R of other four-coordinated Lewis aluminum unit sites of structure (AI) are hydrogen groups, and the groups R of still other four-coordinated Lewis aluminum unit sites of structure (AI) are hydroxyl groups.

[0069] In some embodiments, the modified crystalline zeolite material includes a four-coordinated Lewis aluminum unit site of the modified crystalline zeolite material, and these four-coordinated Lewis aluminum unit sites include at least two of (a), (b) and (c): (a) a four-coordinated Lewis aluminum unit site having an environment according to structure (AI) in the zeolite framework, wherein R is an alkyl group; (b) a four-coordinated Lewis aluminum unit site having an environment according to structure (AI) in the zeolite framework, wherein R is a hydrogen group; and (c) a four-coordinated Lewis aluminum unit site having an environment according to structure (AI) in the zeolite framework, wherein R is a hydroxyl group.

[0070] The pore size of the modified crystalline zeolite material can vary according to the original zeolite framework of the zeolite modified to prepare the modified crystalline zeolite material. In some embodiments, the modified crystalline zeolite material can include any combination of micropores, mesopores and macropores. In an exemplary embodiment, the modified crystalline zeolite material can include micropores with a micropore size less than 2nm and mesopores with a pore size of 2nm to 50nm.

[0071] According to some embodiments, the modified crystalline zeolite material may be an alkyl aluminum zeolite, wherein a portion of the groups R at the Lewis aluminum unit site of the structure (AI) or all of the groups R at the Lewis aluminum unit site of the structure (AI) are alkyl groups. In such embodiments, the alkyl aluminum zeolite may be measured by Fourier Transform Infrared Spectroscopy to show a wavelength of 2850 cm -1 Up to 2990cm-1 The spectral bands in the range are characteristic of aluminum-alkyl bonds with tetracoordinated alkyl aluminum sites. In specific exemplary embodiments, the modified crystalline zeolite material can be an alkyl aluminum zeolite, wherein a portion of the groups R at the Lewis aluminum unit site of structure (AI) or all of the groups R at the Lewis aluminum unit site of structure (AI) are isobutyl groups.

[0072] According to some embodiments, the modified crystalline zeolite material may be an aluminum hydride zeolite, wherein a portion of the groups R at the Lewis aluminum unit site of the structure (AI) or all of the groups R at the Lewis aluminum unit site of the structure (AI) are hydrogen groups. In such embodiments, the aluminum hydride zeolite may be measured by Fourier transform infrared spectroscopy to show a peak at 1952 cm -1 The band at is characteristic of aluminum-hydrogen bonding at a four-coordinated aluminum hydride site.

[0073] According to some embodiments, the modified crystalline zeolite material may be a hydroxyaluminum zeolite, wherein a portion of the groups R at the Lewis aluminum unit site of the structure (AI) or all of the groups R at the Lewis aluminum unit site of the structure (AI) are hydroxyl groups. In such embodiments, the hydride aluminum zeolite may be measured by Fourier transform infrared spectroscopy to show a wavelength of 3787 cm -1 The band at is characteristic of the aluminum-hydroxyl bond at the tetracoordinated aluminum hydroxide site.

[0074] Having described modified crystalline zeolite materials according to the embodiments, methods for incorporating tetracoordinated Lewis aluminum unit sites into a crystalline zeolite material having a zeolite framework containing Bronsted aluminum sites will now be described.

[0075] A method for incorporating a tetracoordinated Lewis aluminum unit site into a crystalline zeolite material comprises contacting the crystalline zeolite material with a dialkylaluminum hydride of the empirical formula R2AlH, wherein each R is an alkyl group. The dialkylaluminum hydride reacts with the zeolite framework and forms a tetracoordinated alkylaluminum site. The resulting modified crystalline zeolite material is an alkylaluminum zeolite. The tetracoordinated alkylaluminum unit site has an environment in the zeolite framework according to structure (BI):

[0076]

[0077] In structure (BI), each Si Q It is the silicon atom of the zeolite framework and is bonded to four oxygen atoms.

[0078] In an embodiment of a method for incorporating a tetracoordinated Lewis aluminum unit site into a crystalline zeolite material, the crystalline zeolite material can be any zeolite that includes a Bronsted aluminum site and also includes sites other than the Bronsted aluminum site that are reactive to dialkylaluminum hydrides. In this regard, "zeolite" includes a crystalline material having a framework composed of aluminum, silicon, and oxygen and having optional substitutions or replacements. Generally, zeolites are described as aluminosilicates having a three-dimensional framework and molecular-sized pores. Certain zeolite materials are ordered porous crystalline aluminosilicates having a well-defined crystalline structure determined by X-ray diffraction, in which there are a large number of smaller cavities that can be interconnected by many smaller channels or windows. In a particular zeolite material, the size of these cavities and pores is uniform. Because the size of these pores makes it possible to accept adsorbed molecules of certain sizes while rejecting adsorbed molecules of larger sizes, these materials are called "molecular sieves" and are used in various ways to exploit these properties. According to an embodiment, the term "zeolite" with respect to a crystalline zeolite material may also include any member of the group of structured aluminosilicate minerals including cations such as sodium, calcium, barium, beryllium, lithium, potassium, magnesium, strontium, or combinations thereof, generally conforming to the nominal formula H x Al x Si 1-x O2, where H can be replaced by any other monovalent cation or (when x associated with H is divisible by the valence) a multivalent cation.

[0079] The term "zeolite" with respect to the crystalline zeolitic material of the embodiments further includes "zeolite-related materials" or "zeolite-types" which are crystalline zeolites formed by replacing Si with other elements. 4+ or Al 3+ Preparation, as in the case of aluminophosphates (eg MeAPO, SAPO, EIAPO, MeAPSO and EIAPSO), gallophosphates, zincphosphates and titanosilicates.

[0080] In an embodiment, the crystalline zeolite material zeolite may include any of the following crystalline porous materials, which have a framework according to the structure type defined by the International Zeolite Association as described in the Zeolite Framework Types database of the IZA structure commission, such as ABW, ACO, AEI, AEL, AEN, AET, AFG AFI, AFN, AFO, AFR, AFS, AFT, AFX, AFY, AHT, ANA, APC, APD, AST, ASV, ATN, ATO, ATS, ATT, ATV, AWO, AWW, BCT, *BEA, BEC, BIK, BOG, BPH, BRE, CAN, CAS, CDO, CFI, CGF, CGS, CHA, CHI, CLO, CON, CZP, DAC, DDR, DFO, DFT , DOH, DON, EAB, EDI, EMT, EON, EPI, ERI, ESV, ETR, EUO, EZT, FAR, FAU, FER, FRA, GIS, GIU, GME, GON, GOO, H EU, IFR, IHW, IMF, ISV, ITE, ITH, ITW, IWR, IWV, IWW, JBW, KFI, LAU, LEV, LIO, LIT, LOS, LOV, LTA, LTL, LTN , MAR, MAZ, MEI, MEL, MEP, MER, MFI, MFS, MON, MOR, MOZ, MSE, MSO, MTF, MTN, MTT, MTW, MWW, NAB, NAT, NES, N ON, NPO, NSI, OBW, OFF, OSI, OSO, OWE, PAR, PAU, PHI, PON, RHO, RON, RRO, RSN, RTE, RTH, RUT, RWR, RWY, SAO , SAS, SAT, SAV, SBE, SBN, SBS, SBT, SFE, SFF, SFG, SFH, SFN, SFO, SGT, SIV, SOD, SOS, SSF, SSY, STF, STI, STO, STT, SZR, TER, THO, TOL, TON, TSC, TUN, UEI, UFI, UOZ, USI, UTL, VET, VFI, VNI, VSV, WEI, WEN, YUG and ZON. According to an embodiment, the crystalline zeolite material may include an intergrown zeolite, wherein the crystalline zeolite material includes at least two independent intergrown zeolite portions within a single zeolite crystal, and the intergrown zeolite portions include zeolite portions of at least two different framework types, each framework type being selected from the aforementioned framework types.

[0081] Generally, porous materials are divided by pore size. For example, materials with pore size less than 2 nanometers are classified as microporous materials, materials with pore size between 2nm and 50nm are classified as mesoporous materials, and materials with pore size greater than 50nm are classified as macroporous materials. According to the crystalline zeolite material of an embodiment, it can be microporous, mesoporous, macroporous, or can have any one, two or three kinds of multiple pore size selected from micropore, mesopore and macropore, including the pore size less than 2nm or greater than 50nm in any case. It should be understood that non-zeolite mesoporous silica, such as MCM-41 and SBA-15, can show significant microporosity. However, the microporosity of this type is disordered and not clearly defined, and should not be considered as the microporosity of zeolite. It should be understood that the terms "crystalline zeolite material" and "zeolite" in the present disclosure do not cover any type of mesoporous silica.

[0082] In some exemplary embodiments, the crystalline zeolite material may be selected from aluminosilicate zeolites, aluminophosphate zeolites, metal-substituted aluminophosphate zeolites and silicoaluminophosphate zeolites. In some embodiments, the crystalline zeolite material is an aluminosilicate zeolite. For example, the aluminosilicate zeolite includes a silanol group (≡Si-OH) reactive to dialkylaluminum hydride. Particularly with respect to aluminosilicate zeolites. In other exemplary embodiments, the crystalline zeolite material may be an aluminosilicate zeolite having the following framework: an MFI framework, a *BEA framework, a mordenite (MOR) framework, a chabazite (CHA) framework or a faujasite (FAU) framework, including a zeolite containing at least one zeolite part having any of the aforementioned framework types and another zeolite part having a different framework type. In an embodiment, the FAU zeolite may be a Y-type zeolite or a USY zeolite (ultra-stable Y-type zeolite). In a specific non-limiting exemplary embodiment, the crystalline zeolite material may be an aluminosilicate zeolite having an MFI framework, such as a ZSM-5 zeolite or an acidic H-ZSM-5 zeolite.

[0083] The dialkyl aluminum hydride of empirical formula R2AlH can be a dimer or a monomer. In an embodiment, the dialkyl aluminum hydride of empirical formula R2AlH is a stable monomer compound. Non-limiting examples of stable monomer dialkyl aluminum hydride compounds of formula R2AlH include those compounds disclosed in U.S. Patents 4,170,604 and 3,015,669. The two groups R of dialkyl aluminum hydride can be the same or different. In certain embodiments, the two groups R of dialkyl aluminum hydride are the same. As used for the group R of dialkyl aluminum hydride, the term "alkyl" is understood in its broadest sense to refer to a saturated hydrocarbon group, which is a straight chain or a branched chain, including only carbon atoms and hydrogen atoms, and including, for example, 1 to 50 carbon atoms, 1 to 40 carbon atoms, 1 to 30 carbon atoms, 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to 5 carbon atoms, 1 to 4 carbon atoms, 3 to 10 carbon atoms, 4 to 10 carbon atoms or 3 to 5 carbon atoms.

[0084] Specific examples of the straight chain alkyl group R of the dialkylaluminum hydride include, but are not limited to, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl and n-decyl. Examples of the branched chain alkyl group R of the dialkylaluminum hydride include the formula -CH2CR 1 R 2 R 3 A group in which R 1 , R 2 and R 3 are independently (C1-C5)alkyl or hydrogen, provided that R 1 , R 2 and R 3 At least one of them is (C1-C5) alkyl. Non-limiting examples of these groups include 2,2-dimethylpropyl (neopentyl) and 3,3-dimethylbutyl (neohexyl). Other examples of branched alkyl groups of the group R of dialkylaluminum hydride include the formula -CH(R 1 )-CH(R 2 )(R 3 ) group, wherein R 1 and R 2 One of them is hydrogen, and R 1 and R 2 The other is a straight chain or branched chain (C4-C 15 ) alkyl, and R 3 Is a straight chain or branched chain (C4-C 15 Non-limiting examples of such groups include 1-methylpropyl (sec-butyl), 2-methylpropyl (isobutyl), 1-methylbutyl (sec-pentyl), 2-methylbutyl, 1-methylpentyl, and 2-methylpentyl.

[0085] In a specific non-limiting embodiment, each R is an isobutyl group. In such embodiments, the group R of the dialkylaluminum hydride and the group R of the Lewis aluminum single site of structure (BI) of the modified crystalline zeolitic material is an isobutyl group.

[0086] According to some embodiments, the reaction of the dialkylaluminum hydride with the zeolite framework causes the aluminum atom and one alkyl group R of the dialkylaluminum hydride to attach to the zeolite framework, while losing a hydrocarbon compound RH as a by-product. For example, when the dialkylaluminum hydride is diisobutylaluminum hydride, the isobutylaluminum species attach to the zeolite framework and produce gaseous isobutane molecules.

[0087] According to an embodiment, when the dialkylaluminum hydride reacts with the zeolite framework, the Bronsted aluminum sites of the crystalline zeolite material do not react with the dialkylaluminum hydride. In some embodiments, the crystalline zeolite material can be an aluminosilicate zeolite. When the crystalline zeolite material is an aluminosilicate zeolite, the dialkylaluminum hydride can selectively react with the silanol groups of the aluminosilicate zeolite without reacting with the Bronsted aluminum sites of the crystalline zeolite material.

[0088] In some embodiments, the method for incorporating a tetracoordinate Lewis aluminum unit point into a crystalline zeolite material may further include dehydroxylating the crystalline zeolite material before the crystalline zeolite material is contacted with a dialkylaluminum hydride. Dehydroxylating the crystalline zeolite material may include heating the crystalline zeolite material at a temperature of at least 600°C, optionally under vacuum or flowing gas, the dehydroxylating time being sufficient to remove residual water from the pores of the zeolite and produce separated silanols while eliminating or preventing the formation of vicinal silanol species. In an exemplary embodiment, the dehydroxylating time may be at least 10 hours. It is believed that by optimizing the amount of available functional substances reactive to dialkylaluminum hydrides in the crystalline zeolite material, dehydroxylating can form separated tetracoordinate aluminum.

[0089] In embodiments, the reaction of the dialkylaluminum hydride with the zeolite framework may increase the mass percentage of aluminum in the zeolite framework by at least 0.01%, at least 0.02%, at least 0.05%, at least 0.1%, at least 0.2%, at least 0.5%, at least 1%, at least 2%, at least 5%, or at least 10%, relative to the mass percentage of aluminum in the crystalline zeolite material before the reaction. In this regard, the increase in the mass percentage of aluminum is calculated by dividing the difference between the mass percentage of aluminum in the alkylaluminum zeolite and the mass percentage of aluminum in the crystalline zeolite material before the reaction with the dialkylaluminum hydride by the mass percentage of aluminum in the crystalline zeolite material before the reaction with the dialkylaluminum hydride and multiplying by 100. The mass percentage of aluminum in the zeolite before and after the reaction is calculated on an oxide basis. In an embodiment, in the alkylaluminum zeolite, 0.01% to 50%, or 0.01% to 10%, or 0.01% to 5%, or 0.01% to 2%, or 0.01% to 1% of all aluminum atoms in the alkylaluminum zeolite can exist as tetracoordinated alkylaluminum unit sites in the zeolite framework.

[0090] The alkylaluminum zeolite prepared according to the embodiment can be measured by Fourier transform infrared spectroscopy (FTIR) to show the following bands, which have the characteristics of aluminum-alkyl bonds of a tetracoordinated alkylaluminum unit point. In the embodiment, the bands having the characteristics of aluminum-alkyl bonds of a tetracoordinated alkylaluminum unit point may appear at 2850 cm -1 Up to 2990cm -1 Without wishing to be bound by theory, it is believed that the wavenumber range of the characteristic peaks for the aluminum-alkyl bond of the tetracoordinated alkylaluminum unit site is independent of the identity of the alkyl group R and, therefore, may be dependent on indicating the presence of any type of alkylaluminum site according to the previously defined structure (BI).

[0091] The method for incorporating tetracoordinate Lewis aluminum unit sites into a crystalline zeolite material can further include converting all or a portion of the alkyl aluminum sites of the alkyl aluminum zeolite into aluminum hydride sites, thereby forming a modified crystalline zeolite material, i.e., an aluminum hydride zeolite. Converting the alkyl aluminum sites into aluminum hydride sites can include thermally treating or heating the alkyl aluminum zeolite to cause at least a portion of the β-hydrogen of the alkyl R to be eliminated. After eliminating at least a portion of the β-hydrogen of the alkyl R from the sites having structure (BI), tetracoordinate aluminum hydride unit sites are formed, and these tetracoordinate aluminum hydride unit sites have an environment in the zeolite framework according to structure (B-II):

[0092]

[0093] In structure (B-II), each Si Q It is the silicon atom of the zeolite framework and is bonded to four oxygen atoms.

[0094] The heat treatment of the alkylaluminum zeolite can be carried out by heating the alkylaluminum zeolite at a peak treatment temperature of, for example, 200°C to 500°C, or 300°C to 500°C, or 300°C to 450°C, or 350°C to 450°C, or about 400°C. The peak treatment temperature can be achieved by heating the alkylaluminum zeolite at a heating rate of 1°C to 20°C from ambient conditions and maintaining a holding time of 10 minutes to 6 hours at the peak temperature, for example, for a desired time or until the β-hydrogen elimination reaction is complete. In some embodiments, a lower peak temperature or a shorter heating time may result in a modified crystalline zeolite material including both aluminum hydride sites and alkylaluminum sites. The peak treatment temperature must be high enough to induce β-hydrogen elimination, but low enough to avoid rearrangement of the zeolite framework, such as loss of Lewis aluminum sites or rejection of framework aluminum from the zeolite framework. In an embodiment, the heating can be carried out in any suitable reactor under vacuum conditions.

[0095] In an embodiment, in an aluminum hydride zeolite, at least 0.01%, or at least 0.1%, or at least 1%, or at least 10%, or 0.01% to 50%, or 0.01% to 10%, or 0.01% to 5%, or 0.01% to 2%, or 0.01% to 1% of all the aluminum atoms in the aluminum hydride zeolite can be present as tetracoordinated aluminum hydride unit sites in the zeolite framework.

[0096] The aluminum hydride zeolite prepared according to the embodiment may show the following bands by FTIR measurement, which have the characteristics of aluminum-hydrogen bonds of a tetracoordinate aluminum hydride unit site. In the embodiment, the bands having the characteristics of aluminum-hydrogen bonds of a tetracoordinate aluminum hydride unit site may appear at about 1952 cm -1 FTIR spectrum at .

[0097] The method for incorporating a tetracoordinated Lewis aluminum unit site into a crystalline zeolite material may further include converting all or a portion of the aluminum hydride sites of the aluminum hydride zeolite into hydroxyaluminum sites, thereby forming a modified crystalline zeolite material, i.e., an aluminum hydroxy zeolite. The conversion of the aluminum hydride sites to aluminum hydroxide sites may include oxidizing the aluminum hydride zeolite. The tetracoordinated aluminum hydroxide unit site has an environment in the zeolite framework according to structure (B-III):

[0098]

[0099] In structure (B-III), each Si Q It is the silicon atom of the zeolite framework and is bonded to four oxygen atoms.

[0100] Oxidation can be carried out in the presence of any oxidizing gas or oxidizing liquid, which has an oxidizing capacity sufficient to oxidize the aluminum hydride site to an aluminum hydroxide site. In a non-limiting exemplary embodiment, the oxidizing gas can include nitrous oxide (N2O), oxygen, iodosobenzene (PhIO) or a mixture of nitrous oxide and oxygen. The example of an oxidizing liquid can include peroxide. Oxidation can be carried out at high temperatures such as 70°C to 200°C, or 90°C to 150°C, or about 100°C for a sufficient time to ensure that oxidation continues to the desired completion state. The oxidation time can be 10 minutes to 5 days, or 1 hour to 5 days, or 24 hours to 5 days, or about 2 days. In some embodiments, a lower oxidation temperature, a weaker oxidizing gas or a shorter oxidation heating time may obtain a modified crystalline zeolite material including both aluminum hydroxide sites and aluminum hydride sites. In some embodiments, after oxidation, the modified crystalline zeolite material may include alkyl aluminum sites, aluminum hydride sites and aluminum hydroxide sites. It is expected that a variety of such sites within a single zeolite framework may yield the ability to tune and optimize the characteristics of the zeolite in terms of catalyst selectivity, catalyst activity, or both, depending on the desired catalyst process.

[0101] In an embodiment, in a hydroxyaluminum zeolite, at least 0.01%, or at least 0.1%, or at least 1%, or at least 10%, or 0.01% to 50%, or 0.01% to 10%, or 0.01% to 5%, or 0.01% to 2%, or 0.01% to 1% of all the aluminum atoms in the hydroxyaluminum zeolite can be present as tetracoordinated aluminum hydroxide unit sites in the zeolite framework.

[0102] The alkylaluminum zeolite prepared according to the embodiment may show the following bands by FTIR measurement, which have the characteristics of aluminum-hydroxyl bonds at a tetracoordinated aluminum hydroxide unit point. In the embodiment, the bands having the characteristics of aluminum-hydroxyl bonds at a tetracoordinated alkylaluminum unit point may appear at about 3787 cm -1 FTIR spectrum at .

[0103] Examples

[0104] Certain embodiments of the present disclosure will be better understood by reference to the following examples, which are provided by way of illustration, and those skilled in the art will recognize that these examples are not meant to be limiting.

[0105] Example 1

[0106] Preparation of Alkyl Aluminum Zeolite

[0107] In this example, a fiber fractionated ZSM-5 (FH-ZSM-5) aluminosilicate zeolite was functionalized to include a tetracoordinated alkylaluminum unit site. The provided FH-ZSM-5 was characterized by energy dispersive X-ray (EDX) analysis and transmission electron microscopy (TEM). Figure 1 The EDX spectrum of the provided FH-ZSM-5 is provided in FIG. 4 TEM micrographs of different parts of the provided FH-ZSM-5 are shown in FIG. Figures 2A-2D Provided.

[0108] Before alkylation, FH-ZSM-5 was heated at 700 °C and 10 -5 Dehydroxylation was carried out at 1000 mbar for 30 hours. Figure 3 One aspect of the dehydroxylation reaction is schematically illustrated. Figure 3 The reaction schematic illustrates a portion of fresh FH-ZSM-5 starting material and a portion of dehydroxylated material as a product. During the dehydroxylation reaction, silanol hydroxyl groups and protons of aluminum-oxygen-silicon bridges are removed in the form of water molecules to form reactive sites on the aluminosilicate framework.

[0109] The dehydroxylated FH-ZSM-5 was characterized by EDX analysis, selected area electron diffraction (SAED), TEM and Fourier transform infrared (FTIR) spectroscopy. Figure 4 The EDX spectrum of dehydroxylated H-ZSM-5 is provided in . Figure 5 The SAED patterns of dehydroxylated H-ZSM-5 are provided in Figure 1. Four TEM micrographs of different parts of dehydroxylated FH-ZSM-5 are shown in Figure 2. Figures 6A-6D Provided.

[0110] Figure 7 One aspect of the alkylation reaction is schematically illustrated. Figure 7 As shown in the schematic diagram of , after the dehydroxylated material is reacted with dialkylaluminum hydride (R2AlH), alkylaluminum sites are incorporated into the zeolite framework. In this example, the R of the dialkylaluminum hydride is isobutyl, and the dialkylaluminum hydride is diisobutylaluminum hydride (DIBAL). During the reaction, one isobutane molecule is released for each Al-R site formed.

[0111] The alkylation reaction is carried out under an inert atmosphere. 0.5 g of dehydroxylated H-ZSM-5 is introduced into the first compartment of a double Schlenk tube. 3 mL of anhydrous and degassed pentane and a solution of one equivalent of diisobutylaluminum hydride (DIBAL-H) ​​in 1.0 M hexane (calculated relative to the amount of silanol present after dehydroxylation) are stirred in the second compartment of the double Schlenk tube at room temperature for 5 minutes. The transfer of the DIBAL-H solution to the H-ZSM-5 is carried out in liquid nitrogen. The reaction is maintained at room temperature for one hour under stirring. Volatiles are removed by filtration, and the white solid is washed twice with anhydrous pentane to remove unreacted DIBAL-H. The resulting solid is placed in a dynamic vacuum (10 -5 The mixture was dried at 400 mbar for 12 hours.

[0112] Through EDX, SAED, TEM, FTIR, 27 Al solid-state nuclear magnetic resonance (SS-NMR) and proton ( 1 H) SS-NMR analysis of alkylaluminum zeolites, specifically isobutylaluminum zeolite. Figure 8 The EDX spectrum of isobutylaluminum zeolite is provided in . Fig. 9 The SAED pattern of isobutyl aluminum zeolite is provided in . Two TEM micrographs of different parts of isobutyl aluminum zeolite are shown in Fig. 10A and 10B Provided.

[0113] Fig.11 The superimposed FTIR spectra of (i) dehydroxylated FH-ZSM-5 before reaction with DIBAL; and (ii) isobutyl aluminum zeolite obtained by reaction of dehydroxylated FH-ZSM-5 with DIBAL. The vibration of isobutyl group appears at 2965-2864 cm -1 [ν as (CH3),ν as (CH2)] and 1465cm -1 [δ as (CH3)] at 2189cm -1 Broad bands are characteristic of silicon hydride materials.

[0114] The FTIR spectrum of the isobutylaluminum zeolite illustrates several aspects of the reaction chemistry. First, the 3750 cm-1 peak due to Si-OH vibrations -1 The decrease in the intensity of the peak at 3611 cm-1 from the dehydroxylated FH-ZSM-5 to the isobutyl aluminum zeolite may indicate that DIBAL has essentially reacted with the silanols in the zeolite framework. Unexpectedly, after the DIBAL reaction, the peak at 3611 cm-1 attributed to the Al-OH vibration -1 The peak at 140° still exists. Based on the retention of this peak, it is believed that DIBAL not only reacts with the silanol species, but also reacts selectively with them, without reacting with the Bronsted aluminum sites. Therefore, it was determined by FTIR that the alkyl aluminum zeolite includes a supported isobutyl aluminum species ( Figure 7 Substances in 1), silane hydride substances ( Figure 7 Substance 2) and isobutyl siloxane substance ( Figure 7 Substances in 3).

[0115] Alkyl aluminum 27 Al SS-NMR spectrum is Fig. 22 The trace of the superimposed spectrum in (i). 1 H SS-NMR spectrum is Fig.23 SS-NMR spectroscopy will be discussed in more detail in Example 3.

[0116] Example 2

[0117] Preparation of aluminum hydride zeolite

[0118] The aluminum alkyl zeolite prepared according to Example 1 was converted to aluminum hydride zeolite. Fig.12 One aspect of the hydride formation reaction is schematically illustrated in , whereby, upon thermal treatment of an alkylaluminum zeolite, various hydrides are formed on the zeolite framework.

[0119] As described in Example 1, the alkyl aluminum zeolite generally comprises Fig.12 The three materials 1, 2 and 3 shown, wherein R is isobutyl. The alkylaluminum zeolite of Example 1 was introduced into a glass reactor (275 mL). The reactor was heated from room temperature to 400°C at a heating rate of 8°C / hour and at 400°C under dynamic vacuum (10 -5 The heat treatment under vacuum causes the elimination of the β-hydrogen of the isobutyl groups on the zeolite framework, while releasing olefins (C x H 2x ), specifically isobutylene (2-methylpropene).

[0120] Through EDX, SAED, TEM, FTIR, 27 Al SS-NMR and 1 The aluminum hydride zeolite was analyzed by H SS-NMR. Fig.13 The EDX spectrum of aluminum hydride zeolite is provided in. Fig.14 The SAED patterns of aluminum hydride zeolite are provided in FIG. 4 TEM micrographs of different parts of aluminum hydride zeolite are shown in FIG. Figures 15A-15D Provided.

[0121] Fig.16 The superimposed FTIR spectra of (i) isobutyl aluminum zeolite obtained by reacting dehydroxylated FH-ZSM-5 with DIBAL; and (ii) aluminum hydride zeolite after heat treatment of isobutyl aluminum zeolite. The FTIR spectrum of aluminum hydride zeolite shows that the FTIR spectrum of 2958-2871 cm -1 [ν as (CH3),ν s (CH2)] and 1468cm -1 [δ as (CH3)], the vibration band of isobutyl is greatly reduced. The Al-H band appears at 1952 cm -1 [ν(Al-H)].

[0122] The FTIR spectrum of the aluminum hydride zeolite illustrates several aspects of the reaction chemistry. First, the 1952 cm -1 The band at 3738cm -1The band at 3611 cm is attributed to silanol species [Si-OH]. -1 The band at 2257 cm-1 demonstrates the retention and non-reaction of the Brønsted aluminum sites during the heat treatment. -1 The band at 2958 cm is attributed to the silane dihydride species. Finally, in the aluminum hydride zeolite, relative to the alkyl aluminum zeolite, both bands at 2958 cm are attributed to the carbon-hydrogen stretching in the alkyl aluminum zeolite. -1 、2929cm -1 、2909cm -1 、2871cm -1 and 1468cm -1 The peak at 1468 cm-1 decreased, proving that the isobutyl group was essentially replaced by a hydrogen group after the β-elimination reaction. -1 The retention of the peak at indicates the presence of isobutylsiloxane species. Therefore, by FTIR, it was determined that the aluminum hydride zeolite includes a supported aluminum hydride species ( Fig.12 Substances in 4), silane hydride substances ( Fig.12 Substances in 2), isobutyl siloxane substances ( Fig.12 Substances in 3), silane dihydride substances ( Fig.12 5) and tetraoxo-coordinated aluminum species ( Fig.12 Substances in 6).

[0123] Aluminum hydride 27 Al SS-NMR spectrum is Fig. 22 The trace of the superimposed spectrum in (ii). 1 H SS-NMR spectrum is Fig.23 The trajectory of the superimposed spectrum in (ii) will be discussed in more detail in Example 3. Fig. 22 and Fig.23 SS-NMR spectrum of

[0124] Example 3

[0125] Preparation of Hydroxyaluminum Zeolite

[0126] The aluminum hydride zeolite of Example 2 was converted to aluminum hydroxy zeolite. Fig.17 One aspect of the hydroxyl forming reaction is schematically illustrated in , whereby, upon oxidation of an aluminum hydride zeolite, aluminum hydride species in the zeolite framework are converted to aluminum hydroxy species in the zeolite framework.

[0127] The aluminum hydride zeolites prepared according to Examples 1 and 2 were subjected to an oxidation step to oxidize the [Al-H] surface species to form [Al-OH] species. The oxidation was performed by exposing the aluminum hydride zeolites to N2O (0.7 bar) at 100°C for 2 days. The zeolites were characterized by EDX, SAED, TEM, FTIR, 27 Al SS-NMR and1 The oxidation product hydroxyaluminum zeolite was analyzed by H SS-NMR. Fig.18 The EDX spectrum of the hydroxyaluminum zeolite is provided in . Fig.19 The SAED patterns of the hydroxyaluminum zeolite are provided in FIG. 4 TEM micrographs of different parts of the hydroxyaluminum zeolite are shown in FIG. Figures 20A-20D Provided.

[0128] The FTIR spectrum of hydroxyaluminum zeolite is as follows Fig.21 This spectrum demonstrates that [Al-H] is completely converted to [Al-OH] by oxidation treatment in nitrous oxide. Specifically, the 1952 cm -1 The band at 3787 cm -1 A new band appeared at 3611 cm, representing the [Al-OH] Lewis site in the hydroxyaluminum zeolite. -1 The band at 3741 cm-1 demonstrates the retention and non-reaction of the Brønsted aluminum sites during oxidation. Other notable bands are at 3741 cm-1. -1 The silanol band at 2260 cm -1 and 2186cm -1 The spectral band of silyl hydride at 2965cm -1 、2877cm -1 and 1468cm -1 The bands at the positions of the carbon-hydrogen stretching and vibration can be clearly seen. Therefore, by FTIR, it was determined that the hydroxyaluminum zeolite includes supported aluminum hydroxyl species ( Fig.17 Substance 7), silane hydride substance ( Fig.17 Substances in 2), isobutyl siloxane substances ( Fig.17 Substances in 3), silane dihydride substances ( Fig.17 5) and tetraoxo-coordinated aluminum species ( Fig.17 Substances in 6).

[0129] Fig. 22 of 27The Al SS-NMR spectrum shows the evolution of the aluminum environment from (i) the alkyl aluminum zeolite of Example 1 to (ii) the hydride aluminum zeolite of Example 2 to (iii) the hydroxy aluminum zeolite of this Example 3. The aluminum atom [Al(O)6] affected by six neighboring oxygen atoms exhibits a peak at about 0.85 ppm. The aluminum atom [Al(O)5] affected by five neighboring oxygen atoms exhibits a peak at about 29.2 ppm. The aluminum atom [Al(O)4] affected by four neighboring oxygen atoms exhibits a peak at about 52.5 ppm. For alkyl aluminum zeolites and hydride aluminum zeolites, the Al(O)6 peak is dominant, while for hydroxy aluminum zeolites, the Al(O)4 peak is dominant. It is believed that the Al(O)4 peak of hydroxy aluminum zeolite is increased due to [Al-OH] species. In all cases, 27 Al SS-NMR spectra demonstrate that the alkylaluminum zeolites, aluminum hydride zeolites, and aluminum hydroxy zeolites include tetracoordinated aluminum atoms in the respective zeolite frameworks.

[0130] Similarly, Fig.23 of 1 The H SS-NMR spectrum shows the evolution of the aluminum environment from (i) the alkylaluminum zeolite of Example 1 to (ii) the aluminum hydride zeolite of Example 2 to (iii) the hydroxyaluminum zeolite of this Example 3. The vertical lines highlight the peak areas of particular interest. Line A is the peak position of the hydrogen atoms on the [≡Al-OH] species, where only the hydroxyaluminum zeolite shows a signal. Line B is the peak position of the hydrogen atoms of silyl hydride [≡Si-H], silyl dihydride [=Si(H)2] and aluminum hydride [≡Al-H], where only the aluminum hydride zeolite and the hydroxyaluminum zeolite show a signal. Line C is the peak position of the single hydrogen atom on the beta carbon atom of the isobutyl group of [≡Si-CH2CH(CH3)2] and [≡Al-CH2CH(CH3)2]. All three zeolites show signals at this position, and the peak of the alkyl aluminum zeolite is the most prominent because in addition to the isobutyl siloxane substance [≡Si-CH2CH(CH3)2], there is also an isobutyl aluminum substance [≡Al-CH2CH(CH3)2]. Line D is the peak position corresponding to the stretching of six equivalent hydrogen atoms on the terminal methyl group of the isobutyl group in [≡Si-CH2CH(CH3)2] and [≡Al-CH2CH(CH3)2]. All three zeolites include significant peaks at this position, and the peak of the alkyl aluminum zeolite is the most prominent because in addition to the isobutyl siloxane substance [≡Si-CH2CH(CH3)2], there is also an isobutyl aluminum substance [≡Al-CH2CH(CH3)2]. Line E is the peak position of two equivalent hydrogen atoms on the α carbon atom of the isobutyl group [≡Si-CH2CH(CH3)2] and [≡Al-CH2CH(CH3)2]. The peaks corresponding to these hydrogen atoms are difficult to discern as shoulders next to the strong peak at line D.

[0131] Project List

[0132] Embodiments of the present disclosure include at least the following items, which are not intended to limit the scope of the present disclosure as a whole or the appended claims.

[0133] Item A1: A modified crystalline zeolite material having a zeolite framework, the zeolite framework comprising a tetracoordinated Lewis aluminum unit site and a Bronsted aluminum site incorporated into the zeolite framework, the tetracoordinated Lewis aluminum unit site having an environment in the zeolite framework according to the structure (AI) described hereinabove, wherein: each R is independently selected from the group consisting of an alkyl group, a hydrogen group, and a hydroxyl group; and each Si Q is a silicon atom of the zeolite framework and is bonded to four oxygen atoms, the Bronsted aluminum site having an environment in the zeolite framework according to structure (A-II) as described hereinabove, wherein each Si Q It is the silicon atom of the zeolite framework and is bonded to four oxygen atoms.

[0134] Item A2: The modified crystalline zeolite material according to Item A1, wherein each R in the zeolite framework is independently selected from the group consisting of isobutyl group, hydrogen group and hydroxyl group.

[0135] Item A3: A modified crystalline zeolite material according to Item A1 or A2, wherein the four-coordinated Lewis aluminum unit site of the modified crystalline zeolite material comprises at least two of (a), (b) and (c): (a) a four-coordinated Lewis aluminum unit site having an environment according to structure (AI) in the zeolite framework, wherein R is an alkyl group; (b) a four-coordinated Lewis aluminum unit site having an environment according to structure (AI) in the zeolite framework, wherein R is a hydrogen group; and (c) a four-coordinated Lewis aluminum unit site having an environment according to structure (AI) in the zeolite framework, wherein R is a hydroxyl group.

[0136] Item A4: The modified crystalline zeolite material according to any one of the preceding items, wherein each R in the zeolite framework is independently selected from the group consisting of isobutyl, hydrogen and hydroxyl groups.

[0137] Item A5: A modified crystalline zeolite material according to any one of the preceding items, wherein the four-coordinated Lewis aluminum unit site of the modified crystalline zeolite material comprises at least two of (a), (b) and (c): (a) a four-coordinated Lewis aluminum unit site having an environment according to structure (AI) in the zeolite framework, wherein R is an isobutyl group; (b) a four-coordinated Lewis aluminum unit site having an environment according to structure (AI) in the zeolite framework, wherein R is a hydrogen group; and (c) a four-coordinated Lewis aluminum unit site having an environment according to structure (AI) in the zeolite framework, wherein R is a hydroxyl group.

[0138] Item A6: The modified crystalline zeolite material according to Item A1, wherein each R is a hydrogen group.

[0139] Item A7: The modified crystalline zeolite material according to Item A1, wherein each R is a hydroxyl group.

[0140] Item A8: The modified crystalline zeolite material according to Item A1, wherein each R is (C1-C 20 )alkyl.

[0141] Item A9: The modified crystalline zeolite material according to Item A1, wherein each R is an isobutyl group.

[0142] Item A10: A modified crystalline zeolite material according to any one of the preceding items, wherein the modified crystalline zeolite material shows at least one band selected from (a), (b), (c) and a combination thereof as measured by Fourier transform infrared spectroscopy: (a) at 2850 cm -1 Up to 2990cm -1 The bands in the range of 1952 cm-1 are characteristic of the aluminum-alkyl bond at the tetracoordinated aluminum alkyl unit point; (b) the bands in the range of 1952 cm-1 are characteristic of the aluminum-alkyl bond at the tetracoordinated aluminum alkyl unit point; (c) the bands in the range of 1952 cm-1 are characteristic of the aluminum-alkyl bond at the tetracoordinated aluminum alkyl unit point. -1 The band at 3787 cm-1 is characteristic of the aluminum-hydrogen bond at a tetracoordinate aluminum hydride unit point; and (c) -1 The band at is characteristic of an aluminum-hydroxyl bond at a four-coordinated Lewis aluminum unit site.

[0143] Item A11: The modified crystalline zeolite material according to any one of the preceding items, wherein the modified crystalline zeolite material is an aluminosilicate zeolite modified to include the four-coordinated Lewis aluminum unit site.

[0144] Item A12: The modified crystalline zeolite material according to any one of the preceding items, wherein the modified crystalline zeolite material is a zeolite having an MFI framework modified to include four-coordinated Lewis aluminum unit sites.

[0145] Item A13: A modified crystalline zeolite material according to any one of the preceding items, wherein the modified crystalline zeolite material is a ZSM-5 zeolite modified to include a four-coordinated Lewis aluminum unit site, an H-ZSM-5 zeolite modified to include a four-coordinated Lewis aluminum unit site, or a FH-ZSM-5 zeolite modified to include a four-coordinated Lewis aluminum unit site.

[0146] Item A14: The modified crystalline zeolite material according to any one of the preceding items, wherein the modified crystalline zeolite material is selected from aluminosilicate zeolites, aluminophosphate zeolites, metal-substituted aluminophosphate zeolites and silicoaluminophosphate zeolites.

[0147] Item A15: The modified crystalline zeolite material according to any one of the preceding items, wherein the modified crystalline zeolite material is an aluminosilicate zeolite.

[0148] Item A16: A modified crystalline zeolite material according to any one of the preceding items, wherein the modified crystalline zeolite material comprises micropores having a micropore size of less than 2 nm and mesopores having a mesopore size of 2 nm to 50 nm.

[0149] Item B1: A method for incorporating a tetracoordinated Lewis aluminum unit site into a crystalline zeolite material, wherein the crystalline zeolite material has a zeolite framework containing Bronsted aluminum sites, the method comprising: contacting the crystalline zeolite material with a dialkylaluminum hydride of the empirical formula R2AlH, wherein each R is an alkyl group, so that the dialkylaluminum hydride reacts with the zeolite framework and forms a tetracoordinated alkylaluminum unit site, wherein the tetracoordinated alkylaluminum unit site has an environment in the zeolite framework according to the structure (BI) described hereinabove, wherein each Si Q It is the silicon atom of the zeolite framework that is bonded to four oxygen atoms to form a modified crystalline zeolite material, namely an alkylaluminum zeolite.

[0150] Item B2: The method according to Item B1, wherein the Bronsted aluminum sites of the crystalline zeolite material do not react with the dialkylaluminum hydride.

[0151] Item B3: A method according to Item B1 or B2, wherein: the crystalline zeolite material is an aluminosilicate zeolite; the dialkylaluminum hydride selectively reacts with the silanol groups of the aluminosilicate zeolite; and the Bronsted aluminum sites of the crystalline zeolite material do not react with the dialkylaluminum hydride.

[0152] Item B4: The method according to any one of Items B1 to B3, wherein the alkyl aluminum zeolite has a peak intensity of 2850 cm-1 as measured by Fourier transform infrared spectroscopy. -1 Up to 2990cm -1 The spectral bands in the range are characteristic of the aluminum-alkyl bond of the tetracoordinated alkyl aluminum unit point.

[0153] Item B5: A method according to any one of items B1 to B4, wherein each R is an isobutyl group.

[0154] Item B6: The method according to any one of items B1 to B5, further comprising: dehydroxylating the crystalline zeolite material before contacting the crystalline zeolite material with the dialkylaluminum hydride.

[0155] Item B7: A method according to Item B6, wherein dehydroxylating the crystalline zeolite material comprises heating the crystalline zeolite material at a temperature of at least 600°C, and the dehydroxylating time is sufficient to remove residual water from the pores of the crystalline zeolite material and to condense the ortho-hydroxyl groups to release water, thereby forming a separated silanol substance.

[0156] Item B8: A method according to any one of Items B1 to B7, wherein the crystalline zeolite material is an aluminosilicate zeolite selected from the group consisting of: MFI framework zeolite, *BEA framework zeolite, MOR framework zeolite, CHA framework zeolite, FAU framework zeolite, Y-type zeolite, ultra-stable Y-type zeolite (USY), ZSM-5, H-ZSM-5, FH-ZSM-5, and intergrowth zeolite, wherein the intergrowth zeolite contains at least one of the aforementioned aluminosilicate zeolites intergrowthed with another aluminosilicate zeolite of any framework type.

[0157] Item B9: A method according to any one of items B1 to B8, further comprising: heating the alkyl aluminum zeolite to cause the elimination of β-hydrogen of at least a portion of the alkyl R, thereby forming a tetracoordinate aluminum hydride unit site in the zeolite framework having an environment according to structure (B-II) as described hereinabove, wherein each Si Q It is the silicon atom of the zeolite framework that is bonded to four oxygen atoms to form a modified crystalline zeolite material, namely, aluminum hydride zeolite.

[0158] Item 10: The method according to Item B9, wherein the aluminum hydride zeolite is measured by Fourier transform infrared spectroscopy to show that the -1 The spectral band at has the characteristics of aluminum-hydrogen bond at a unit point of four-coordinated aluminum hydride.

[0159] Item B11: A method according to any one of Items B9 to B10, further comprising: oxidizing the aluminum hydride zeolite to convert at least a portion of the four-coordinate aluminum hydride unit sites into four-coordinate aluminum hydroxide unit sites, wherein the four-coordinate aluminum hydroxide unit sites have an environment according to the structure (B-III) described above in the zeolite framework, wherein each Si Q It is the silicon atom of the zeolite framework that is bonded to four oxygen atoms to form a modified crystalline zeolite material, namely, aluminum hydroxy zeolite.

[0160] Item B12: The method according to Item B11, wherein at least 1% of the aluminum atoms in the hydroxyaluminum zeolite are present in the tetracoordinated aluminum hydroxide unit site.

[0161] Item B13: The method according to Item B11 or B12, wherein the hydroxyaluminum zeolite has a peak intensity of 3787 cm-1 as measured by Fourier transform infrared spectroscopy. -1 The spectral band at is characteristic of the aluminum-hydroxyl bond at a tetracoordinated aluminum hydroxide unit point.

[0162] Item B14: A method according to any one of items B1 to B13, wherein the crystalline zeolite material is selected from aluminosilicate zeolites, aluminophosphate zeolites, metal-substituted aluminophosphate zeolites and silicoaluminophosphate zeolites.

[0163] Item B15: A method according to any one of items B1 to B14, wherein the crystalline zeolite material is an aluminosilicate zeolite.

[0164] Item B16: A method according to any one of items B1 to B15, wherein the crystalline zeolite material is an aluminosilicate zeolite having the following framework: an MFI framework, a *BEA framework, a FAU framework, or an intergrown zeolite, wherein the intergrown zeolite contains at least one of the aforementioned aluminosilicate zeolites intergrown with another aluminosilicate zeolite of any framework type.

[0165] Item B17: A method according to any one of items B1 to B16, wherein the crystalline zeolite material is Y-type zeolite or ultrastable Y-type zeolite (USY).

[0166] Item B18: A method according to any one of items B1 to B17, wherein the crystalline zeolite material is ZSM-5, H-ZSM-5 or FH-ZSM-5.

[0167] Item C1: A modified crystalline zeolite material formed according to the method of any one of items B1 to B18.

[0168] Item D1: Use of a modified crystalline zeolite material according to any one of items A1 to A16 or a modified crystalline zeolite material formed by a method according to any one of items B1 to B18 as a catalyst or catalyst additive in an industrial process.

[0169] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. The terms used in the description herein are only used to describe specific embodiments and are not intended to be limiting. As used in the specification and the appended claims, the singular forms "a", "an" and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0170] Although specific embodiments have been illustrated and described herein, it should be understood that various other changes and modifications may be made without departing from the spirit and scope of the claimed subject matter. In addition, although various aspects of the claimed subject matter have been described herein, such aspects need not be used in combination. Therefore, the appended claims are intended to cover all such changes and modifications within the scope of the claimed subject matter.

Claims

1. A modified crystalline zeolite material having a zeolite framework, the zeolite framework comprising a tetracoordinated Lewis aluminum unit site and a Bronsted aluminum site incorporated into the zeolite framework, the tetracoordinated Lewis aluminum unit site having an environment in the zeolite framework according to the structure (AI): in: each R is independently selected from the group consisting of an alkyl group, a hydrogen group, and a hydroxyl group; and Each Si Q is the silicon atom of the zeolite framework and is bonded to four oxygen atoms, The Brønsted aluminum sites have an environment in the zeolite framework according to structure (A-II): Among them, each Si Q It is the silicon atom of the zeolite framework and is bonded to four oxygen atoms.

2. The modified crystalline zeolite material according to claim 1, wherein the four-coordinated Lewis aluminum unit site of the modified crystalline zeolite material comprises at least two of (a), (b) and (c): (a) having a four-coordinated Lewis aluminum unit site in the zeolite framework according to the environment of structure (AI), wherein R is an alkyl group; (b) having a four-coordinated Lewis aluminum unit site in the zeolite framework according to the environment of structure (AI), wherein R is a hydrogen radical; and (c) having a four-coordinated Lewis aluminum unit site in the zeolite framework according to the environment of structure (AI), wherein R is a hydroxyl group.

3. The modified crystalline zeolite material according to claim 1, wherein the modified crystalline zeolite material shows at least one band selected from (a), (b), (c) or a combination thereof as measured by Fourier Transform Infrared Spectroscopy: (a) at 2850 cm -1 Up to 2990cm -1 The bands in the range of 40 to 50 are characteristic of aluminum-alkyl bonds at tetracoordinated aluminum alkyl sites; or (b) at 1952 cm -1 The band at is characteristic of an aluminum-hydrogen bond at a tetracoordinated aluminum hydride site; or (c) at 3787cm -1 The band at is characteristic of an aluminum-hydroxyl bond at a four-coordinated Lewis aluminum site.

4. The modified crystalline zeolite material according to any one of claims 1 to 3, wherein each R in the zeolite framework is independently selected from the group consisting of isobutyl, hydrogen and hydroxyl groups.

5. The modified crystalline zeolite material according to claim 4, wherein the four-coordinated Lewis aluminum unit site of the modified crystalline zeolite material comprises at least two of (a), (b) and (c): (a) having a four-coordinated Lewis aluminum unit site in the zeolite framework according to the environment of structure (AI), wherein R is isobutyl; (b) having a four-coordinated Lewis aluminum unit site in the zeolite framework according to the environment of structure (AI), wherein R is a hydrogen radical; and (c) having a four-coordinated Lewis aluminum unit site in the zeolite framework according to the environment of structure (AI), wherein R is a hydroxyl group.

6. The modified crystalline zeolite material according to any one of claims 1 to 3, wherein the modified crystalline zeolite material is an aluminosilicate zeolite modified to include the four-coordinated Lewis aluminum unit site.

7. A method of incorporating tetracoordinated Lewis aluminum unit sites into a crystalline zeolite material having a zeolite framework comprising Bronsted aluminum sites having a structure (A- II ) environment: The method comprises: The crystalline zeolite material is contacted with a dialkylaluminum hydride of the empirical formula R2AlH, wherein each R is an alkyl group, so that the dialkylaluminum hydride reacts with the zeolite framework and forms a tetracoordinated alkylaluminum unit site having an environment in the zeolite framework according to structure (BI): Among them, each Si Q It is the silicon atom of the zeolite framework and is bonded to four oxygen atoms to form a modified crystalline zeolite material, an alkylaluminum zeolite.

8. The method according to claim 7, wherein: The crystalline zeolite material is an aluminosilicate zeolite; The dialkylaluminum hydride selectively reacts with the silanol groups of the aluminosilicate zeolite; and The Bronsted aluminium sites of the crystalline zeolitic material are not reactive with the dialkylaluminium hydride.

9. The method according to claim 7, wherein the alkyl aluminum zeolite shows a peak at 2850 cm-1 as measured by Fourier transform infrared spectroscopy. -1 Up to 2990cm -1 The bands in the range are characteristic of aluminum-alkyl bonds at tetracoordinated alkyl aluminum sites.

10. The method of claim 7, wherein each R is isobutyl.

11. The method according to claim 7, further comprising: Prior to contacting the crystalline zeolite material with the dialkylaluminum hydride, the crystalline zeolite material is dehydroxylated by heating the crystalline zeolite material at a temperature of at least 600° C. for a time sufficient to remove residual water from the pores of the crystalline zeolite material to allow condensation of vicinal hydroxyls to release water, thereby forming separate silanol species.

12. The method according to claim 11, further comprising: The alkylaluminum zeolite is heated to cause beta-hydrogen elimination of at least a portion of the alkyl groups R, thereby forming a tetracoordinated aluminum hydride unit site in the zeolite framework having an environment according to structure (B-II): Among them, each Si Q is the silicon atom of the zeolite framework and is bonded to four oxygen atoms to form a modified crystalline zeolite material, aluminum hydride zeolite, wherein the aluminum hydride zeolite is measured by Fourier transform infrared spectroscopy to have a wavelength of 1952 cm -1 The spectral band at is characterized by aluminum-hydrogen bonding at the tetracoordinate aluminum hydride site.

13. The method according to claim 12, further comprising: Oxidizing the aluminum hydride zeolite to convert at least a portion of the tetracoordinate aluminum hydride unit sites to tetracoordinate aluminum hydroxide unit sites having an environment in the zeolite framework according to structure (B-III): Among them, each Si Q is the silicon atom of the zeolite framework and is bonded to four oxygen atoms to form a modified crystalline zeolite material hydroxyaluminum zeolite, wherein the hydroxyaluminum zeolite is measured by Fourier transform infrared spectroscopy to have a wavelength of 3787 cm -1 The spectrum bands at The characteristic is the aluminum-hydroxyl bond at the unit point of the tetracoordinated aluminum hydroxide.

14. The method of claim 13, wherein at least 1% of the aluminum atoms in the aluminum hydroxy zeolite are present in the tetracoordinated aluminum hydroxide unit site.

15. The method according to any one of claims 7 to 14, wherein the crystalline zeolite material is an aluminosilicate zeolite selected from the group consisting of: MFI framework zeolite, *BEA framework zeolite, MOR framework zeolite, CHA framework zeolite, FAU framework zeolite, and intergrown zeolites, wherein the intergrown zeolite contains at least one of the foregoing aluminosilicate zeolites intergrown with another aluminosilicate zeolite of any framework type.

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