Synthesis of zeolitic material with aft framework structure and scr catalyst comprising the same

Abstract

This invention relates to a method for preparing aluminosilicate zeolites having an AFT framework structure, the method comprising (1) providing a synthetic mixture comprising (A) an Al2O3 source; (B) a SiO2 source; (C1) a first organic structure directing agent source comprising an N,N,N,N,N′,N′,N′-hexaethylalkylene diammonium cation; and optionally a second organic structure directing agent source comprising a cation selected from the group consisting of (C2-i) a quaternary ammonium cation of formula (I), (C2-ii) a piperidinium cation of formula (II), and (C2-iii) a pyrrolidineium cation of formula (III); and (2) subjecting the synthetic mixture to crystallization conditions to form an AFT zeolite, wherein formulas (I), (II), and (III) are as defined in the specification and claims. The invention also relates to an SCR catalyst composition comprising an aluminosilicate zeolite having an AFT framework structure and a co-catalyst metal, and the use of the aluminosilicate zeolite for the selective catalytic reduction of nitrogen oxides.

Description

Technical Field

[0001] This invention relates to a method for synthesizing zeolite materials with an AFT framework structure, the use of the zeolite materials for selective catalytic reduction (SCR) of nitrogen oxides, and SCR catalysts containing the zeolite materials. Background Technology

[0002] Small-pore zeolites with pore sizes smaller than 5 angstroms (Å), such as those of the CHA, AEI, or AFX types, have been found to perform exceptionally well as adsorbents or catalysts in various applications, such as gas separation or conversion reactions of organic compounds, such as methanol to olefins (MTO). Small-pore zeolites with other framework structures are increasingly attracting the attention of researchers, who hope to find more potential candidates for small-pore zeolite adsorbents or catalysts.

[0003] For example, US Patent No. 10,343,927 B2 describes a novel AFT-type aluminosilicate zeolite. AFT-type zeolites are small-pore zeolites, originally referred to as aluminophosphate (AIPO) framework structures. The AFT-type aluminosilicate zeolite designated as SSZ-112 in US 10,343,927 B2 is prepared from a synthetic gel comprising a SiO2 source, an Al2O3 source, a Group 1 metal source, a hydroxide ion source, and a hexamethylammonium biscation source as a first organic template (Q1) and one or more of 1-methyl-1-alkylpyrrolidine ononium cations and 1-methyl-1-alkylpiperidinonium cations as a second organic template (Q2), wherein each alkyl group is independently C1-C5 alkyl. The patent states that zeolite SSZ-112 can be used as a catalyst for a variety of organic or inorganic conversion processes, including alkylation, cracking, hydrocracking, isomerization, oligomerization, conversion of organic oxygen-containing compounds (e.g., methanol and / or dimethyl ether) into olefins (e.g., ethylene, propylene), synthesis of monoalkylamines and dialkylamines, and catalytic reduction of nitrogen oxides.

[0004] The reported methods for preparing AFT-type aluminosilicate zeolites are limited to very specific organic structure directing agents (OSDA). More methods for preparing AFT-type aluminosilicate zeolites are still needed, particularly those that can provide AFT-type aluminosilicate zeolites with the desired catalytic activity for SCR applications. Summary of the Invention

[0005] One object of the present invention is to provide a novel method for preparing aluminosilicate zeolites with an AFT framework structure.

[0006] This objective is achieved by using an N,N,N,N',N',N'-hexaethylalkylene diammonium organic structure directing agent and optionally another organic structure directing agent selected from quaternary ammonium organic structure directing agents, piperidinium organic structure directing agents and pyrrolidineonium organic structure directing agents.

[0007] Another object of the present invention is to provide an SCR catalyst based on zeolite with an AFT framework structure, which has the desired activity, in particular combined with excellent anti-aging stability at high temperatures, such as 800°C or higher.

[0008] It has been surprisingly found that this objective is achieved through an SCR catalyst composition comprising an aluminosilicate zeolite with an AFT framework structure and a co-catalyst metal.

[0009] Therefore, in one aspect, the present invention relates to a method for preparing aluminosilicate zeolites having an AFT framework structure, the method comprising:

[0010] (1) Provide a synthetic mixture containing

[0011] (A) Al2O3 source,

[0012] (B) SiO2 source,

[0013] (C1) A first organic structure directing agent source comprising an N,N,N,N',N',N'-hexaethylalkylene diammonium cation, wherein the alkylene moiety is a substituted or unsubstituted straight-chain or branched chain, and

[0014] (C2) A second organic structure directing agent source, comprising a cation selected from the group consisting of the following:

[0015] (C2-i) is the quaternary ammonium cation represented by formula (I).

[0016] (I)

[0017] in

[0018] R1, R2, and R3 are independently C1-C8 alkyl groups, and

[0019] R4 is selected from C1-C8 alkyl groups, C3-C4 alkyl groups, and C4 alkyl groups. 10 cycloalkyl, C6-C 10 Aryl and C7-C 20 Arylalkyl groups, each optionally substituted with one or more hydroxyl groups;

[0020] (C2-ii) Piperidineonium cation represented by formula (II),

[0021] (II)

[0022] in

[0023] R a and R b Independently selected from C1-C8 alkyl and C3-C 10 Cycloalkyl groups, or together with the nitrogen atoms bonded to them, form 5- or 6-membered saturated or unsaturated rings, and

[0024] R c R d R e R f and R g Each is independently H, hydroxyl, or C1-C8 alkyl;

[0025] or

[0026] in

[0027] R a and R e They connect together to form C1-C3 bonds, such as ethylene bonds.

[0028] R b It is a C1-C8 alkyl group, and

[0029] R c R d R f and R g Each being independently of H, hydroxyl, or C1-C8 alkyl; and

[0030] (C2-iii) The pyrrolidineonium cation represented by formula (III),

[0031] (III)

[0032] in

[0033] R o and R p Each is independently a C1-C8 alkyl or C3-C 10 cycloalkyl, and

[0034] R q R r R s and R t Each is independently H, hydroxyl, or C1-C8 alkyl;

[0035] as well as

[0036] (2) subject the synthetic mixture to crystallization conditions to form AFT zeolite.

[0037] In this respect, the present invention also relates to a method for preparing aluminosilicate zeolites having an AFT framework structure, the method comprising:

[0038] (1) Provide a synthetic mixture containing

[0039] (A) Al2O3 source,

[0040] (B) SiO2 source,

[0041] (C) An organic structure-directing agent source comprising an N,N,N,N',N',N'-hexaethylalkylene diammonium cation, wherein the alkylene moiety is a substituted or unsubstituted straight-chain or branched chain, and

[0042] (2) subject the synthetic mixture to crystallization conditions to form AFT zeolite.

[0043] In another aspect, the present invention relates to an aluminosilicate zeolite having an AFT framework structure that can be obtained and / or acquired by the methods described herein.

[0044] In another aspect, the present invention relates to an SCR catalyst composition comprising an aluminosilicate zeolite having an AFT framework structure obtained and / or obtainable by the methods described herein, and a co-catalyst metal.

[0045] In another aspect, the present invention relates to a catalytic article in the form of an extrusion comprising an SCR catalyst composition or in the form of a bulk material comprising a washcoat containing an SCR catalyst composition on a substrate, wherein the SCR catalyst composition comprises an aluminosilicate zeolite having an AFT framework structure and a cocatalyst metal.

[0046] In another aspect, the present invention relates to an exhaust gas treatment system comprising an internal combustion engine and an exhaust gas duct in fluid communication with the internal combustion engine, wherein a catalyst as described herein is present in the exhaust gas duct. Attached Figure Description

[0047] Figure 1 SEM images of the zeolites (materials A to I) of Examples 1 to 9 are shown respectively.

[0048] Figure 2 The XRD patterns of the zeolites (materials A to I) of Examples 1 to 9 are shown respectively. Detailed Implementation

[0049] The present invention will now be described in detail. It should be understood that the present invention can be implemented in many different ways and should not be construed as being limited to the embodiments set forth herein.

[0050] In this document, the singular forms “a,” “an,” and “the / said” include plural indicators unless the context clearly indicates otherwise. The terms “comprising,” “including,” etc., are used interchangeably with “containing,” “having,” etc., and are interpreted in a non-restrictive, open-ended manner. That is, additional parts or elements may be present, for example. Expressions such as “consisting of,” “substantially consisting of,” or cognates may be included within “comprising” or cognates.

[0051] As used in this article, the term "AFT" refers to the type of AFT skeleton recognized by the International Zeolite Association (IZA) Structural Committee.

[0052] In the context of zeolites, the term "aluminosilicate" is intended to refer to a framework primarily composed of aluminum oxide and silicon dioxide, which may or may not contain framework metals other than aluminum and silicon. When a framework metal other than aluminum replaces one or more aluminum or silicon framework atoms, aluminosilicate zeolites may be referred to as "metal-substituted".

[0053] As used herein, the terms “zeolite with AFT framework structure,” “AFT-type zeolite,” “AFT zeolite,” etc., are intended to refer to materials displaying XRD patterns of AFT framework structures and will be used interchangeably with each other hereinafter. These terms are also intended to include any form of zeolite, such as synthesized as is, calcined, NH4-exchanged, H-form, and metal-substituted forms.

[0054] As used herein, the term "as is" refers to zeolite in its post-synthetic form after crystallization and drying, before the removal of the organic structure-directing agent.

[0055] As used in this article, the term "calcined form" is intended to refer to zeolite in its calcined form.

[0056] In a first aspect, the present invention provides a method for preparing aluminosilicate zeolites having an AFT framework structure, the method comprising:

[0057] (1) Provide a synthetic mixture containing

[0058] (A) Al2O3 source,

[0059] (B) SiO2 source,

[0060] (C1) A first organic structure directing agent source comprising an N,N,N,N',N',N'-hexaethylalkylene diammonium cation (OSDA1), wherein the alkylene moiety is a substituted or unsubstituted straight-chain or branched chain, and

[0061] (C2) A second organic structure directing agent source, comprising a cation selected from the group consisting of (OSDA2).

[0062] (C2-i) is the quaternary ammonium cation represented by formula (I).

[0063] (I)

[0064] in

[0065] R1, R2, and R3 are independently C1-C8 alkyl groups, and

[0066] R4 is selected from C1-C8 alkyl groups, C3-C4 alkyl groups, and C4 alkyl groups. 10 cycloalkyl, C6-C 10 Aryl and C7-C 20 Arylalkyl groups, each optionally substituted with one or more hydroxyl groups; and

[0067] (C2-ii) Piperidineonium cation represented by formula (II),

[0068] (II)

[0069] in

[0070] R a and R b Independently selected from C1-C8 alkyl and C3-C 10 Cycloalkyl groups, or together with the nitrogen atoms bonded to them, form 5- or 6-membered saturated or unsaturated rings, and

[0071] R c R d R e R f and R g Each is independently H, hydroxyl, or C1-C8 alkyl;

[0072] or

[0073] in

[0074] R a and R e They connect together to form C1-C3 bonds, such as ethylene bonds.

[0075] R b It is a C1-C8 alkyl group, and

[0076] R c R d R f and R g Each being independently of H, hydroxyl, or C1-C8 alkyl; and

[0077] (C2-iii) The pyrrolidineonium cation represented by formula (III),

[0078] (III)

[0079] in

[0080] R o and R p Each is independently a C1-C8 alkyl or C3-C 10 cycloalkyl, and

[0081] R q R r R s and R t Each is independently H, hydroxyl, or C1-C8 alkyl;

[0082] (2) subject the synthetic mixture to crystallization conditions to form AFT zeolite.

[0083] The first organic structure directing agent specifically comprises N,N,N,N',N',N'-hexaethylalkylene diammonium cation (OSDA1), wherein the alkylene moiety is selected from substituted or unsubstituted straight-chain or branched C3-C moieties. 10 Alkyl groups, preferably unsubstituted straight-chain or branched C3-C. 10 Alkyl group.

[0084] The first organic structure directing agent preferably comprises an N,N,N,N',N',N'-hexaethylalkylene diammonium cation (OSDA1) represented by formula (IV):

[0085] (C2H5)3N + (CH2) n N + (C2H5)3 (IV)

[0086] in

[0087] n is an integer ranging from 3 to 10, preferably from 4 to 7, and most preferably 5.

[0088] In some embodiments, the first organic structure directing agent comprises a cation selected from the group consisting of N,N,N,N',N',N'-hexaethyl-1,3-propanediammonium, N,N,N,N',N',N'-hexaethyl-1,4-butanediammonium, N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium, N,N,N,N',N',N'-hexaethyl-1,6-hexammonium, N,N,N,N',N',N'-hexaethyl-1,7-heptanediammonium, and any combination thereof. Preferably, the first organic structure directing agent comprises a cation selected from the group consisting of N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium, N,N,N,N',N',N'-hexaethyl-1,6-hexammonium, N,N,N,N',N',N'-hexaethyl-1,7-heptanediammonium, and any combination thereof, more preferably N,N,N,N',N',N',N'-hexaethyl-1,5-pentanediammonium.

[0089] In some embodiments, the second organic structure directing agent specifically comprises (C2-i) a quaternary ammonium cation represented by formula (I),

[0090] (I)

[0091] in

[0092] R1, R2, and R3 are independently selected from C1-C4 alkyl groups, and

[0093] R4 is selected from C1-C4 alkyl, C5-C8 cycloalkyl, phenyl, and benzyl groups, each optionally substituted with one or more hydroxyl groups.

[0094] The second organic structure directing agent preferably comprises (C2-i) a quaternary ammonium cation represented by formula (I), wherein R1, R2 and R3 are independently methyl, ethyl, n-propyl or isopropyl; and R4 is selected from methyl, ethyl, n-propyl, isopropyl, cyclopentyl, cyclohexyl, cycloheptyl, phenyl and benzyl, each optionally substituted with one or more hydroxyl groups.

[0095] More preferably, the second organic structure directing agent comprises (C2-i) selected from N,N,N-triethylmethylammonium, N,N,N-trimethyl-2-hydroxyethylammonium, N,N,N-trimethylethylammonium, tetraethylammonium, N,N,N-trimethylcyclopentylammonium, N,N,N-trimethylcyclohexylammonium, N,N,N-trimethylcycloheptylammonium, N,N-dimethyl-N-ethylcyclopentylammonium, N,N-dimethyl-N-ethylcyclohexylammonium, N,N-dimethyl-N-ethylcycloheptylammonium, N,N-diethyl-N-ethylcycloheptylammonium, N,N-diethyl-N-ethylcycloheptylammonium, N,N-diethyl-N-ethylcycloheptylammonium, N,N-diethyl-N-ethylcyclopentylammonium, N,N-dimethyl ...methyl-N-ethylcyclopentylammonium, N,N-dimethyl-N-ethylcycloheptylammonium, N,N-dimethyl-N-ethylcyclopentylammonium, N,N-dimethyl-N-ethylcycloheptylammonium, N,N-dimethyl-N-ethylcyclopentylammonium, N,N-dimethyl-N-ethylcyclopentylammonium, N,N-dimethyl-N-ethyl -N-methylcyclopentylammonium, N,N-diethyl-N-methylcyclohexylammonium, N,N-diethyl-N-methylcycloheptylammonium, N,N,N-trimethylphenylammonium, N,N-triethylphenylammonium, N,N-dimethyl-N-ethylphenylammonium, N-methyl-N,N-diethylphenylammonium, N,N,N-trimethylbenzylammonium, N,N,N-triethylbenzylammonium, N,N-dimethyl-N-ethylbenzylammonium, N-methyl-N,N-diethylbenzylammonium and any combination thereof are quaternary ammonium cations.

[0096] In some exemplary embodiments, the second organic structure directing agent comprises (C2-i) a quaternary ammonium cation selected from the group consisting of N,N,N-triethylmethylammonium, N,N,N-trimethyl-2-hydroxyethylammonium, tetraethylammonium, N,N,N-trimethylcyclohexylammonium, N,N-dimethyl-N-ethylcyclohexylammonium, N,N-diethyl-N-methylcyclohexylammonium, N,N,N-trimethylphenylammonium, N,N-dimethyl-N-ethylphenylammonium, N-methyl-N,N-diethylphenylammonium, and any combination thereof. Preferably, the second organic structure directing agent comprises (C2-i) a quaternary ammonium cation selected from the group consisting of tetraethylammonium, N,N-dimethyl-N-ethylcyclohexylammonium, and combinations thereof.

[0097] In some other embodiments, the second organic structure directing agent specifically comprises (C2-ii) a piperidinium cation represented by formula (II):

[0098] (II)

[0099] in

[0100] R a and R b Independently selected from C1-C5 alkyl and C5-C 10 Cycloalkyl groups, or together with the nitrogen atoms they are bonded to, form 5- or 6-membered saturated or unsaturated rings.

[0101] R c and R g For H, and

[0102] R d R e and Rf Each of the following is independently H, hydroxyl, or C1-C5 alkyl; or

[0103] in

[0104] R a and R e They connect together to form C1-C3 bonds, such as ethylene bonds.

[0105] R b It is a C1-C5 alkyl group.

[0106] R c and R g For H, and

[0107] R d and R f Each is independently H, hydroxyl, or C1-C5 alkyl.

[0108] The second organic structure directing agent preferably comprises (C2-ii) a piperidinium cation represented by formula (II), wherein R a and R b Each is independently a C1-C5 alkyl group, R c and R g For H, and R d R e and R f Each is independently H, hydroxyl, or C1-C5 alkyl.

[0109] More preferably, the second organic structure directing agent comprises (C2-ii) a piperidinium cation represented by formula (II), wherein R a It is a C1-C3 alkyl group, R b It is a C1-C5 alkyl group, R d and R f Each is independently H or C1-C5 alkyl, and R c R e and R g For H.

[0110] In some exemplary embodiments, the second organic structure directing agent comprises (C2-ii) a piperidinium cation selected from 1,1-dimethylpiperidinium, 1,1,3,5-tetramethylpiperidinium, 1-methyl-1-ethylpiperidinium, 1-methyl-1-n-propylpiperidinium, 1-methyl-1-n-butylpiperidinium, 1,1-diethylpiperidinium, 1-ethyl-1-n-propylpiperidinium, 1-ethyl-1-n-butylpiperidinium, and any combination thereof. Preferably, the second organic structure directing agent comprises (C2-ii) a piperidinium cation selected from the group consisting of 1-methyl-1-n-propylpiperidinium, 1-methyl-1-n-butylpiperidinium, 1-ethyl-1-n-propylpiperidinium, and any combination thereof.

[0111] In some other embodiments, the second organic structure directing agent specifically comprises (C2-iii) a pyrrolidineonium cation represented by formula (III):

[0112] (III)

[0113] in

[0114] R o and R p Each is independently a C1-C5 alkyl group, and

[0115] R q R r R s and R t Each is independently H, hydroxyl, or C1-C5 alkyl;

[0116] or

[0117] in

[0118] R o and R p One of them is a C1-C5 alkyl group and the other is a C5-C4 alkyl group. 10 cycloalkyl, and

[0119] R q R r R s and R t Each is independently H, hydroxyl, or C1-C5 alkyl.

[0120] The second organic structure directing agent preferably comprises (C2-iii) a pyrrolidine-onium cation represented by formula (III), wherein R o and R p Each is independently a C1-C5 alkyl group, and R q R r R s and R t For H.

[0121] In some exemplary embodiments, the second organic structure directing agent comprises (C2-iii) a pyrrolidineonium cation selected from 1-methyl-1-ethylpyrrolidineonium, 1-methyl-1-n-propylpyrrolidineonium, 1-methyl-1-n-butylpyrrolidineonium, 1,1-diethylpyrrolidineonium, 1-ethyl-1-n-propylpyrrolidineonium, 1-ethyl-1-n-butylpyrrolidineonium, and any combination thereof. Preferably, the second organic structure directing agent comprises (C2-iii) a pyrrolidineonium cation selected from the group consisting of 1-methyl-1-n-propylpyrrolidineonium, 1-methyl-1-n-butylpyrrolidineonium, and any combination thereof.

[0122] In some preferred embodiments of the method for preparing aluminosilicate zeolites having an AFT framework structure, the first organic structure directing agent comprises an N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium cation, and the second organic structure directing agent comprises (C2-i) a quaternary ammonium cation selected from the group consisting of N,N,N-triethylmethylammonium, N,N,N-trimethyl-2-hydroxyethylammonium, tetraethylammonium, N,N,N-trimethylcyclohexylammonium, N,N-dimethyl-N-ethylcyclohexylammonium, N,N-diethyl-N-methylcyclohexylammonium, N,N,N-trimethylphenylammonium, N,N-dimethyl-N-ethylphenylammonium, N-methyl-N,N-diethylphenylammonium, and any combination thereof. (C2-ii) is a piperidinium cation selected from 1,1-dimethylpiperidine, 1,1,3,5-tetramethylpiperidine, 1-methyl-1-ethylpiperidine, 1-methyl-1-n-propylpiperidine, 1-methyl-1-n-butylpiperidine, 1,1-diethylpiperidine, 1-ethyl-1-n-propylpiperidine, 1-ethyl-1-n-butylpiperidine, and any combination thereof; or (C2-iii) is a pyrrolidine cation selected from 1-methyl-1-ethylpyrrolidine, 1-methyl-1-n-propylpyrrolidine, 1-methyl-1-n-butylpyrrolidine, 1,1-diethylpyrrolidine, 1-ethyl-1-n-propylpyrrolidine, 1-ethyl-1-n-butylpyrrolidine, and any combination thereof.

[0123] In some other preferred embodiments of the method for preparing aluminosilicate zeolites having an AFT framework structure, the first organic structure directing agent comprises an N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium cation, and the second organic structure directing agent comprises: (C2-i) a quaternary ammonium cation selected from the group consisting of tetraethylammonium, N,N-dimethyl-N-ethylcyclohexylammonium, and combinations thereof; (C2-ii) a piperidinium cation selected from the group consisting of 1-methyl-1-n-propylpiperidine, 1-methyl-1-n-butylpiperidine, 1-ethyl-1-n-propylpiperidine, and any combination thereof; or (C2-iii) a pyrrolidine cation selected from the group consisting of 1-methyl-1-n-propylpyrrolidine, 1-methyl-1-n-butylpyrrolidine, and any combination thereof.

[0124] The first organic structure directing agent and the second organic structure directing agent can be used in a molar ratio of the corresponding cations in the range of 10:1 to 1:30, or 5:1 to 1:30, or 4:1 to 1:25, preferably 3:1 to 1:25, more preferably 3:1 to 1:20.

[0125] In some exemplary embodiments of the method for preparing aluminosilicate zeolites with an AFT framework structure, the second organic structure directing agent comprises a (C2-i) quaternary ammonium cation, and the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to quaternary ammonium cation in the range of 10:1 to 1:5, or 5:1 to 1:1, preferably 3:1 to 2:1. More preferably, the first organic structure directing agent comprises an N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium cation, and the second organic structure directing agent comprises (C2-i) a quaternary ammonium cation selected from the group consisting of N,N,N-triethylmethylammonium, N,N,N-trimethyl-2-hydroxyethylammonium, tetraethylammonium, N,N,N-trimethylcyclohexylammonium, N,N-dimethyl-N-ethylcyclohexylammonium, N,N-diethyl-N-methylcyclohexylammonium, N,N,N-trimethylphenylammonium, N,N-dimethyl-N-ethylphenylammonium, N-methyl-N,N-diethylphenylammonium, and any combination thereof, preferably tetraethylammonium, N,N-dimethyl-N-ethylcyclohexylammonium, and combinations thereof.

[0126] In some other exemplary embodiments of the method for preparing aluminosilicate zeolites having an AFT framework structure, the second organic structure directing agent comprises a (C2-ii)piperidinium cation, and the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to piperidinium cation in the range of 1:1 to 1:30, or 1:2 to 1:25, preferably 1:4 to 1:25, more preferably 1:5 to 1:20. More preferably, the first organic structure directing agent comprises an N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium cation, and the second organic structure directing agent comprises (C2-ii) a piperidinium cation selected from the group consisting of 1,1-dimethylpiperidinium, 1,1,3,5-tetramethylpiperidinium, 1-methyl-1-ethylpiperidinium, 1-methyl-1-n-propylpiperidinium, 1-methyl-1-n-butylpiperidinium, 1,1-diethylpiperidinium, 1-ethyl-1-n-propylpiperidinium, 1-ethyl-1-n-butylpiperidinium, and any combination thereof, preferably 1-methyl-1-n-propylpiperidinium, 1-methyl-1-n-butylpiperidinium, 1-ethyl-1-n-propylpiperidinium, and any combination thereof.

[0127] In some other exemplary embodiments of the method for preparing aluminosilicate zeolites with an AFT framework structure, the second organic structure directing agent comprises (C2-iii)pyrrolidineonium cation, and the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to pyrrolidineonium cation in the range of 1:1 to 1:30, or 1:2 to 1:25, preferably 1:4 to 1:20, more preferably 1:5 to 1:15. More preferably, the first organic structure directing agent comprises an N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium cation, and the second organic structure directing agent comprises (C2-iii) a pyrrolidineonium cation selected from 1-methyl-1-ethylpyrrolidineonium, 1-methyl-1-n-propylpyrrolidineonium, 1-methyl-1-n-butylpyrrolidineonium, 1,1-diethylpyrrolidineonium, 1-ethyl-1-n-propylpyrrolidineonium, 1-ethyl-1-n-butylpyrrolidineonium, and any combination thereof, preferably 1-methyl-1-n-propylpyrrolidineonium, 1-methyl-1-n-butylpyrrolidineonium, and any combination thereof.

[0128] The synthetic mixture may or may not contain additional organic structure-directing agents. In some embodiments, the synthetic mixture does not contain any organic structure-directing agents other than the first and second organic structure-directing agents.

[0129] Suitablely, the first organic structure directing agent and the second organic structure directing agent are independently of each other in the form of halides (such as fluorides, chlorides and bromides), hydroxides, sulfates, nitrates and carboxylates (such as acetates) of the corresponding cations as described above, preferably chlorides, bromides, hydroxides and sulfates.

[0130] Preferably, the first organic structure directing agent and the second organic structure directing agent are hydroxides of the corresponding cations as described above, independently of each other.

[0131] The first organic structure directing agent and the second organic structure directing agent may be present in the synthetic mixture in a total molar ratio of SiO2 source (calculated as the sum of cations (OSDA1 + OSDA2)) to SiO2 in the range of 0.01 to 1.0, preferably 0.03 to 0.5, more preferably 0.05 to 0.3.

[0132] There are no particular limitations on the sources of Al2O3 and SiO2. Suitable examples of Al2O3 sources may include, but are not limited to, alumina, aluminates, aluminum alkoxides, and aluminum salts, with alumina, aluminum tri(C1-C5)alkoxides, AlO(OH), Al(OH)3, aluminum halides, aluminum sulfate, aluminum phosphate, and aluminum fluorosilicates being preferred. Suitable examples of SiO2 sources may include, but are not limited to, pyrolytic silica, precipitated silica, silica hydrosols, silica gel, colloidal silica, silicic acid, silanols, alkali metal silicates, hydrated sodium metasilicates, sesquisilicates, disilicates, and silicate esters. Alternatively or additionally, combined sources of Al2O3 and SiO2 may be used, such as aluminosilicate zeolites like FAU zeolite.

[0133] In some embodiments of the method for preparing aluminosilicate zeolites with an AFT framework structure, FAU zeolite is used as a combined source of Al₂O₃ and SiO₂, as well as an additional source of SiO₂. Specifically, the FAU zeolite is zeolite Y, preferably zeolite Y with a SiO₂ to Al₂O₃ molar ratio not greater than 40, 30, 20, or even 10. The additional source of SiO₂ is selected from the group consisting of pyrolytic silica, precipitated silica, silica hydrosol, silica gel, and colloidal silica.

[0134] The synthetic mixture provided in step (1) may contain a SiO2 source and an Al2O3 source in a molar ratio of 5 to 100, preferably 30 to 80, more preferably 40 to 60, calculated as SiO2 to Al2O3.

[0135] The synthetic mixture provided in step (1) may also contain an alkali metal and / or alkaline earth metal cation (AM) source, preferably an alkali metal cation. The alkali metal is preferably selected from the group consisting of Li, Na, K, Cs, and any combination thereof, more preferably Na and / or K, and most preferably Na. The alkaline earth metal is preferably selected from the group consisting of Mg, Ca, Sr, and Ba. Suitable sources of alkali metal and / or alkaline earth metal cations (AM) are typically halides (such as fluorides, chlorides, and bromides), hydroxides, sulfates, nitrates, and carboxylates (such as acetates) of alkali metals and / or alkaline earth metals, or any combination thereof. Preferably, the alkali metal and / or alkaline earth metal cation (AM) source includes chlorides, bromides, hydroxides, or sulfates of alkali metals and / or alkaline earth metals, or any combination thereof. More preferably, hydroxides of alkali metals are used in the synthetic mixture.

[0136] Alkali metal and / or alkaline earth metal cations (AM) may be present in the synthetic mixture in a molar ratio relative to the SiO2 source (calculated as AM) to the total SiO2 in the range of 0.01 to 1.0, preferably 0.1 to 1.0, more preferably 0.3 to 0.8.

[0137] The synthetic mixture provided in step (1) may also contain anions OH-. - Source. Useful OH - The source can be, for example, a metal hydroxide, such as an alkali metal hydroxide or ammonium hydroxide. Preferably, the anion OH- - It may be derived from one or more of an alkali metal and / or alkaline earth metal cation (AM) source and a first and / or second organic structure directing agent source.

[0138] OH - The anion can be in the range of 0.1 to 2.0, more preferably 0.2 to 1.0, more preferably 0.5 to 1.0 relative to the SiO2 source (in OH groups). - The total molar ratio of (calculated) SiO2 to the total molar ratio exists in the synthetic mixture.

[0139] The synthetic mixture provided in step (1) may also contain at least one solvent, preferably water, more preferably deionized water. The solvent may be contained in one or more starting materials of the synthetic mixture, such as sources of Al2O3, SiO2 and first and / or second organic structure directing agents, and thus brought into the synthetic mixture, and / or may be incorporated into the synthetic mixture alone.

[0140] In some embodiments, the molar ratio of water to SiO2 source in the synthetic mixture (calculated as H2O to SiO2) is 3 to 100, preferably 10 to 80, and more preferably 20 to 60.

[0141] In some exemplary embodiments, the synthetic mixture provided in step (1) has the molar composition shown in Table 1 below:

[0142] Table 1

[0143]

[0144] 1) The amounts of Al2O3 and SiO2 sources are calculated based on their respective oxides, and

[0145] The amounts of OSDA1 and OSDA2 are calculated in terms of their respective cations.

[0146] In some embodiments, the synthetic mixture provided in step (1) may also contain a certain amount of AFT zeolite seed crystals. The AFT zeolite seed crystals can be obtained by the methods described herein without using seed crystals.

[0147] In step (2), the synthetic mixture can be subjected to crystallization conditions to form AFT zeolite without particular limitations. Crystallization can be carried out at a high temperature in the range of 80°C to 250°C, more preferably 100°C to 200°C, for a sufficient time, for example, 0.5 to 12 days, 1 to 6 days, or 2 to 5 days. Typically, crystallization is carried out under autogenous pressure, for example in a pressure vessel such as an autoclave. Furthermore, crystallization is preferably carried out without stirring.

[0148] The formed aluminosilicate zeolite can be post-processed, including, for example, separation by filtration, optional washing, and drying to obtain the synthesized AFT zeolite as is. Therefore, step (2) in the method according to the invention optionally further includes a post-processing procedure.

[0149] The synthesized AFT zeolite typically contains at least a portion of the first and second organic structure directing agents as described above within its structural pores.

[0150] In some embodiments, the synthesized AFT zeolite from step (2) may be subjected to a calcination process. Therefore, the method according to the invention further includes step (3) of calcining the synthesized AFT zeolite.

[0151] In some implementations, the synthesized or calcined AFT zeolite can be subjected to an ion exchange process, which exchanges one or more ionic non-framework elements contained in the zeolite for H+. + and / or NH4 + Therefore, the method according to the invention also includes

[0152] (4) Replace one or more ionic non-framework elements contained in the zeolite obtained in step (2) or (3) with H. + and / or NH4 + NH4 is preferred + .

[0153] Typically, H has already been exchanged in step (4). + and / or NH4 + The zeolite can undergo post-treatment processes including, for example, separation by filtration, optional washing and drying, and / or calcination. Therefore, step (4) in the method according to the invention optionally further includes post-treatment processes and / or calcination processes.

[0154] The calcination in steps (3) and / or (4) can be carried out at a temperature ranging from 300°C to 900°C, for example, from 350°C to 700°C or from 400°C to 650°C. Specifically, the calcination can be carried out in a gaseous atmosphere having a temperature within the above range, which can be air, oxygen, nitrogen, or a mixture of two or more thereof. Preferably, the calcination is carried out for 0.5 to 10 hours, for example, 3 to 7 hours or 4 to 6 hours.

[0155] In some variations of the method according to the invention for preparing aluminosilicate zeolites with an AFT framework structure, a second organic structure directing agent may be omitted.

[0156] Therefore, the present invention also provides a method for preparing aluminosilicate zeolites having an AFT framework structure, the method comprising:

[0157] (1) Provide a synthetic mixture containing

[0158] (A) Al2O3 source,

[0159] (B) SiO2 source,

[0160] (C) An organic structure-directing agent source comprising an N,N,N,N',N',N'-hexaethylalkylene diammonium cation, wherein the alkylene moiety (OSDA) is a substituted or unsubstituted straight-chain or branched chain, and

[0161] (2) subject the synthetic mixture to crystallization conditions to form AFT zeolite.

[0162] In some specific implementations, organic structure-directing agents other than those containing N,N,N,N',N',N'-hexaethylalkylene diammonium cations are not used in the method according to the variation.

[0163] The N,N,N,N',N',N'-hexaethylalkylene diammonium cation, as generally and preferably described in any of the embodiments above, is applicable here to the method according to variations.

[0164] In some specific embodiments of the variation scheme, the synthetic mixture provided in step (1) may have the molar composition shown in Table 2 below:

[0165] Table 2

[0166]

[0167] 1) The amounts of Al2O3 source and SiO2 source are calculated based on their respective oxides.

[0168] This method can be carried out in the same manner as the method described above using the first organic structure directing agent and the second organic structure directing agent.

[0169] As determined by X-ray powder diffraction (XRD) analysis, aluminosilicate zeolites with an AFT framework structure can be successfully obtained from the method described in the first aspect.

[0170] Therefore, in a second aspect, the present invention also provides an aluminosilicate zeolite with an AFT framework structure that can be obtained and / or acquired from the method described in the first aspect.

[0171] The silica to alumina molar ratio (SAR) of aluminosilicate zeolite with an AFT framework structure is 10 to 25, preferably 11 to 20, more preferably 11 to 18, as determined by its calcined H- form.

[0172] The aluminosilicate zeolites with the AFT framework structure according to the present invention typically have an average crystal size of up to 1 µm, or up to 500 nm, for example, in the range of 200 nm to 500 nm. The average crystal size can be determined by scanning electron microscopy (SEM). Specifically, the average crystal size is determined by SEM by measuring the crystal size of at least 30 different crystals randomly selected from multiple images covering different regions of the sample.

[0173] In some embodiments, the mesopore surface area (MSA) of the aluminosilicate zeolite with the AFT framework structure according to the present invention may not exceed 60 m². 2 / g, preferably not more than 50m 2 / g, more preferably not greater than 45m 2 / g, for example, 1 to 50m 2 / g or 3 to 40m 2 / g. Alternatively or additionally, the aluminosilicate zeolite with an AFT framework structure has a zeolite surface area (ZSA) of at least 400 m². 2 / g, or at least 450m 2 / g, for example, in 450 to 650m 2 / g or 450 to 600m 2 Within the range of / g. The surface area of ​​mesopores and zeolite can be determined by the N2-adsorption porosity determination method.

[0174] The aluminosilicate zeolite with an AFT framework structure according to the present invention is preferably at least 90% phase pure, that is, at least 90% of the zeolite framework is AFT type, as determined by X-ray powder diffraction (XRD) analysis. More preferably, the aluminosilicate zeolite with an AFT framework structure is at least 95% phase pure, or even more preferably at least 98% or at least about 99% phase pure.

[0175] In some embodiments, the aluminosilicate zeolite with the AFT framework structure may contain small amounts (e.g., less than 10%, preferably less than 5%, even more preferably less than 2% or less than 1%) of some other frameworks such as AFX or CHA as symbionts.

[0176] It has been surprisingly found that aluminosilicate zeolites with an AFT framework structure obtained by the method described in the first aspect exhibit significantly higher anti-aging stability at 800 °C or higher in the selective catalytic reduction (SCR) of NOx compared to catalysts containing zeolites with the same framework type but prepared in other ways.

[0177] Therefore, in a third aspect, the present invention also provides an SCR catalyst composition comprising an aluminosilicate zeolite having an AFT framework structure and a co-catalyst metal.

[0178] As used herein, the term "co-catalyst metal" refers to a non-framework metal that can enhance the catalytic activity of zeolite. "Non-framework metal" refers to a metal that does not participate in the formation of the zeolite framework structure. Co-catalyst metals may be present within the zeolite and / or on at least a portion of the zeolite surface, preferably in the form of ionic substances.

[0179] Specifically, the SCR catalyst composition according to the present invention comprises an aluminosilicate zeolite having an AFT framework structure and a co-catalyst metal present within and / or on the aluminosilicate zeolite having an AFT framework structure.

[0180] Aluminosilicate zeolites with an AFT framework structure that can be used in the SCR catalyst compositions according to the invention can be obtained and / or can be obtained by the methods described in the first aspect, or those described in the second aspect. Any general and specific description of the methods in the first aspect or of aluminosilicate zeolites with an AFT framework structure as in the second aspect is incorporated herein by reference.

[0181] The co-catalyst metal can be any metal known to be useful for improving the catalytic performance of zeolites in the selective catalytic reduction (SCR) application of NOx. Typically, the co-catalyst metal can be selected from transition metals (such as noble metals such as Au and Ag and platinum group metals), base metals (such as Cr, Zr, Nb, Mo, Fe, Mn, W, V, Ti, Co, Ni, Cu, and Zn), alkaline earth metals (such as Ca and Mg), and Sb, Sn, and Bi, as well as any combination thereof.

[0182] In a preferred embodiment, the SCR catalyst composition contains at least Cu and / or Fe as a co-catalyst metal. In some specific embodiments, the SCR catalyst composition contains Cu as a co-catalyst metal. Specifically, the co-catalyst metal used in the SCR catalyst composition is composed of Cu.

[0183] Based on the total weight of the co-catalyst metal and the aluminosilicate zeolite with the AFT framework structure, the co-catalyst metal may be present in the SCR catalyst composition in an amount of 0.1 wt% to 10 wt%, preferably 0.5 wt% to 10 wt%, more preferably 1 wt% to 7 wt%, and particularly 2 wt% to 5 wt%, based on the oxide content. In some specific embodiments in which copper, iron, or combinations thereof are used as the co-catalyst metal, the co-catalyst metal is preferably present in the SCR catalyst composition in an amount of 1 wt% to 5 wt%, more preferably 2 wt% to 4 wt%, based on the oxide content, based on the total weight of the co-catalyst metal and the aluminosilicate zeolite with the AFT framework structure.

[0184] Alternatively, the co-catalyst metal may be present in the SCR catalyst composition in an amount of 0.1 mol to 1.0 mol, preferably 0.2 mol to 0.7 mol, more preferably 0.3 mol to 0.5 mol per mole of skeletal aluminum of aluminosilicate zeolite having an AFT framework structure. In some specific embodiments in which copper, iron, or combinations thereof are used as the co-catalyst metal, the amount of the co-catalyst metal is 0.2 mol to 0.7 mol, preferably 0.3 mol to 0.5 mol per mole of skeletal aluminum of aluminosilicate zeolite having an AFT framework structure.

[0185] In some preferred embodiments, the SCR catalyst composition comprises

[0186] - Aluminosilicate zeolites with an AFT framework structure, wherein the molar ratio (SAR) of silica to alumina is 10 to 25, preferably 11 to 20, and

[0187] - A co-catalyst metal present within and / or on the aluminosilicate zeolite, which is Cu and / or Fe, especially Cu.

[0188] The co-catalyst metal is present in an amount of 0.2 to 0.7 moles, preferably 0.3 to 0.5 moles, of skeletal aluminum per mole of aluminosilicate zeolite.

[0189] In some preferred embodiments, the SCR catalyst composition according to the invention comprises

[0190] - Aluminosilicate zeolites with an AFT framework structure, wherein the molar ratio (SAR) of silica to alumina is 11 to 20, more preferably 11 to 18, and

[0191] - Co-catalyst metal Cu present within and / or on aluminosilicate zeolite,

[0192] Cu is present in an amount of 0.3 to 0.5 moles of skeletal aluminum per mole of aluminosilicate zeolite.

[0193] In one exemplary embodiment, the SCR catalyst composition according to the invention comprises

[0194] - Aluminosilicate zeolites with an AFT framework structure, having a silica to alumina molar ratio (SAR) of 11 to 18, and

[0195] - Co-catalyst metal Cu present within and / or on aluminosilicate zeolite,

[0196] Cu is present in an amount of 0.3 to 0.5 moles of skeletal aluminum per mole of aluminosilicate zeolite.

[0197] Co-catalyst metals can be incorporated into aluminosilicate zeolites with an AFT framework structure using any known method, such as ion exchange and impregnation. For example, co-catalyst metals can be incorporated into aluminosilicate zeolites with an AFT framework structure by mixing the aluminosilicate zeolite into a solution of a soluble precursor of the co-catalyst metal. The zeolite after ion exchange with the co-catalyst metal, which is typically in cationic form, can be conventionally washed, dried, and calcined. Useful soluble precursors of the co-catalyst metal can be, for example, salts of the co-catalyst metal, complexes of the co-catalyst metal, and combinations thereof. Alternatively, co-catalyst metals can be incorporated in situ into aluminosilicate zeolites with an AFT framework structure during the preparation of catalytic articles such as extrusions or coated bulk materials.

[0198] It has been found that the SCR catalyst compositions according to the invention exhibit the desired activity in selective catalytic reduction (SCR) applications of NOx. Furthermore, it has been surprisingly found that the SCR catalyst compositions according to the invention also possess excellent anti-aging stability at high temperatures, such as 800°C or higher, particularly when the aluminosilicate zeolite with the AFT framework structure is prepared using a specific combination of organic structure-directing agents as described herein.

[0199] In a fourth aspect, the present invention provides the use of aluminosilicate zeolites having an AFT framework structure, which are obtained and / or obtainable by the methods described herein, in catalysts for selective catalytic reduction (SCR) of NOx.

[0200] For SCR applications, aluminosilicate zeolites with an AFT framework structure (preferably loaded with the co-catalyst metal as described above) can be applied to the monolithic substrate in the form of extrusions or as a carrier coating.

[0201] Therefore, in a fifth aspect, the present invention provides a catalyst article comprising either an extrusion of a catalyst composition or a bulk material comprising a support coating containing the catalyst composition on a substrate, wherein the catalyst composition comprises an aluminosilicate zeolite having an AFT framework structure as described in the second aspect above and a co-catalyst metal, or the catalyst composition is an SCR catalyst composition as described in the third aspect.

[0202] The term "extrudate" generally refers to a molded article formed by extrusion. According to the present invention, extrudates comprising aluminosilicate zeolite with an AFT framework structure and a co-catalyst metal typically have a honeycomb structure.

[0203] The term "carrier coating" has its usual meaning in the art as a thin, adhesive coating of catalytic material or other material applied to a substrate.

[0204] The term "substrate" generally refers to a monolithic material on which a catalytic coating is disposed, such as a monolithic honeycomb substrate, especially a flow-through monolithic substrate and a wall-flow monolithic substrate.

[0205] Aluminosilicate zeolites and co-catalyst metals with AFT framework structures can be processed into application forms by any known method without particular limitations.

[0206] In another aspect, the present invention relates to an exhaust gas treatment system comprising an internal combustion engine and an exhaust gas duct in fluid communication with the internal combustion engine, wherein a catalyst as described herein is present in the exhaust gas duct.

[0207] Implementation Plan

[0208] Various embodiments are listed below. It should be understood that the embodiments listed below can be combined with all aspects of the invention and other embodiments.

[0209] 1. A method for preparing aluminosilicate zeolites with an AFT framework structure, the method comprising:

[0210] (1) Provide a synthetic mixture containing

[0211] (A) Al2O3 source,

[0212] (B) SiO2 source,

[0213] (C1) A first organic structure directing agent source comprising an N,N,N,N',N',N'-hexaethylalkylene diammonium cation, wherein the alkylene moiety is a substituted or unsubstituted straight-chain or branched chain, and

[0214] (C2) A second organic structure directing agent source, comprising a cation selected from the group consisting of the following:

[0215] (C2-i) is the quaternary ammonium cation represented by formula (I).

[0216] (I)

[0217] in

[0218] R1, R2, and R3 are independently C1-C8 alkyl groups, and

[0219] R4 is selected from C1-C8 alkyl groups, C3-C4 alkyl groups, and C4 alkyl groups. 10 cycloalkyl, C6-C 10 Aryl and C7-C 20 Arylalkyl groups, each optionally substituted with one or more hydroxyl groups; and

[0220] (C2-ii) Piperidineonium cation represented by formula (II),

[0221] (II)

[0222] in

[0223] R a and R b Independently selected from C1-C8 alkyl and C3-C 10 Cycloalkyl groups, or together with the nitrogen atoms bonded to them, form 5- or 6-membered saturated or unsaturated rings, and

[0224] R c R d R e R f and R g Each is independently H, hydroxyl, or C1-C8 alkyl;

[0225] or

[0226] in

[0227] R a and R e They connect together to form C1-C3 bonds, such as ethylene bonds.

[0228] R b It is a C1-C8 alkyl group, and

[0229] R c R d R f and R g Each being independently of H, hydroxyl, or C1-C8 alkyl; and

[0230] (C2-iii) The pyrrolidineonium cation represented by formula (III),

[0231] (III)

[0232] in

[0233] R o and R p Each is independently a C1-C8 alkyl or C3-C 10 cycloalkyl, and

[0234] R q R r R s and R t Each is independently H, hydroxyl, or C1-C8 alkyl;

[0235] (2) subject the synthetic mixture to crystallization conditions to form AFT zeolite.

[0236] 2. The method according to embodiment 1, wherein the alkylene moiety in the N,N,N,N',N',N'-hexaethylalkylene diammonium cation is selected from substituted or unsubstituted straight-chain or branched C3-C4 cations. 10 Alkyl groups, preferably unsubstituted straight-chain or branched C3-C. 10 Alkyl group.

[0237] 3. The method according to embodiment 2, wherein the first organic structure directing agent comprises an N,N,N,N',N',N'-hexaethylalkylene diammonium cation represented by formula (IV):

[0238] (C2H5)3N + (CH2) n N + (C2H5)3 (IV)

[0239] in

[0240] n is an integer ranging from 3 to 10, preferably from 4 to 7, and most preferably 5.

[0241] 4. The method according to embodiment 3, wherein the N,N,N,N',N',N'-hexaethylalkylene diammonium cation is selected from N,N,N,N',N',N'-hexaethyl-1,3-propanediammonium, N,N,N,N',N',N'-hexaethyl-1,4-butanediammonium, N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium, N,N,N,N',N',N'-hexaethyl-1,6-hexammonium, N,N The group consisting of N,N',N',N'-hexaethyl-1,7-heptanediammonium and any combination thereof, preferably N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium, N,N,N,N',N',N'-hexaethyl-1,6-hexanediammonium, N,N,N,N',N',N'-hexaethyl-1,7-heptanediammonium and any combination thereof, more preferably N,N,N,N',N',N',N'-hexaethyl-1,5-pentanediammonium.

[0242] 5. The method according to any one of embodiments 1 to 4, wherein the quaternary ammonium cation (C2-i) is represented by formula (I), wherein R1, R2 and R3 are independently selected from C1-C4 alkyl groups, and R4 is selected from C1-C4 alkyl, C5-C8 cycloalkyl, phenyl and benzyl groups, each optionally substituted with one or more hydroxyl groups.

[0243] 6. The method according to embodiment 5, wherein the quaternary ammonium cation (C2-i) is selected from N,N,N-triethylmethylammonium, N,N,N-trimethyl-2-hydroxyethylammonium, N,N,N-trimethylethylammonium, tetraethylammonium, N,N,N-trimethylcyclopentylammonium, N,N,N-trimethylcyclohexylammonium, N,N,N-trimethylcycloheptylammonium, N,N-dimethyl-N-ethylcyclopentylammonium, N,N-dimethyl-N-ethylcyclohexylammonium, N,N-dimethyl-N-ethylcycloheptylammonium, N, The group consisting of N-diethyl-N-methylcyclopentylammonium, N,N-diethyl-N-methylcyclohexylammonium, N,N-diethyl-N-methylcycloheptylammonium, N,N,N-trimethylphenylammonium, N,N-triethylphenylammonium, N,N-dimethyl-N-ethylphenylammonium, N-methyl-N,N-diethylphenylammonium, N,N,N-trimethylbenzylammonium, N,N,N-triethylbenzylammonium, N,N-dimethyl-N-ethylbenzylammonium, N-methyl-N,N-diethylbenzylammonium, and any combination thereof.

[0244] 7. The method according to any one of embodiments 1 to 4, wherein the piperidinium cation (C2-ii) is represented by formula (II), wherein R a and R b Independently selected from C1-C5 alkyl and C5-C 10Cycloalkyl groups, or those bonded to nitrogen atoms forming 5- or 6-membered saturated or unsaturated rings, R c and R g For H, and R d R e and R f Each of the following is independently H, hydroxyl, or C1-C5 alkyl; or R is wherein a and R e They connect together to form C1-C3 bonds, such as ethylene bonds, R b It is a C1-C5 alkyl group, R c and R g For H, and R d and R f Each is independently H, hydroxyl, or C1-C5 alkyl.

[0245] 8. The method according to embodiment 7, wherein the piperidinium cation (C2-ii) is represented by formula (II), wherein R a and R b Each is independently a C1-C5 alkyl group, R c and R g For H, and R d R e and R f Each is independently H, hydroxyl, or C1-C5 alkyl.

[0246] 9. The method according to embodiment 8, wherein the piperidinium cation (C2-ii) is represented by formula (II), wherein R a It is a C1-C3 alkyl group, R b It is a C1-C5 alkyl group, R d and R f Each is independently H or C1-C5 alkyl, and R c R e and R g For H.

[0247] 10. The method according to embodiment 9, wherein the piperidinium cation (C2-ii) is selected from the group consisting of 1,1-dimethylpiperidinium, 1,1,3,5-tetramethylpiperidinium, 1-methyl-1-ethylpiperidinium, 1-methyl-1-n-propylpiperidinium, 1-methyl-1-n-butylpiperidinium, 1,1-diethylpiperidinium, 1-ethyl-1-n-propylpiperidinium, 1-ethyl-1-n-butylpiperidinium, and any combination thereof.

[0248] 11. The method according to any one of embodiments 1 to 4, wherein the pyrrolidine-onium cation (C2-iii) is represented by formula (III), wherein R o and R pEach is independently a C1-C5 alkyl group, and R q R r R s and R t Each of the following is independently H, hydroxyl, or C1-C5 alkyl; or R is wherein o and R p One of them is a C1-C5 alkyl group and the other is a C5-C4 alkyl group. 10 Cycloalkyl, and R q R r R s and R t Each is independently H, hydroxyl, or C1-C5 alkyl.

[0249] 12. The method according to embodiment 11, wherein the pyrrolidine-onium cation (C2-iii) is represented by formula (III), wherein R o and R p Each is independently a C1-C5 alkyl group, and R q R r R s and R t H is preferably 1-methyl-1-ethylpyrrolidineonium, 1-methyl-1-n-propylpyrrolidineonium, 1-methyl-1-n-butylpyrrolidineonium, 1,1-diethylpyrrolidineonium, 1-ethyl-1-n-propylpyrrolidineonium, 1-ethyl-1-n-butylpyrrolidineonium, and any combination thereof.

[0250] 13. The method according to any one of embodiments 1 to 12, wherein the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of corresponding cations in the range of 10:1 to 1:30, or 5:1 to 1:30, or 4:1 to 1:25, preferably 3:1 to 1:25, more preferably 3:1 to 1:20.

[0251] 14. The method according to any one of embodiments 1 to 6, wherein the second organic structure directing agent comprises a (C2-i) quaternary ammonium cation, and the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to quaternary ammonium cation in the range of 10:1 to 1:5, or 5:1 to 1:1, preferably 3:1 to 2:1.

[0252] 15. The method according to any one of embodiments 1 to 4 and 7 to 10, wherein the second organic structure directing agent comprises (C2-ii)piperidinium cation, and the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to piperidinium cation in the range of 1:1 to 1:30, or 1:2 to 1:25, preferably 1:4 to 1:25, more preferably 1:5 to 1:20.

[0253] 16. The method according to any one of embodiments 1 to 4 and 11 to 12, wherein the second organic structure directing agent comprises (C2-iii)pyrrolidine onium cation, and the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to pyrrolidine onium cation in the range of 1:1 to 1:30, or 1:2 to 1:25, preferably 1:4 to 1:20, more preferably 1:5 to 1:15.

[0254] 17. The method according to any one of embodiments 1 to 16, wherein the Al2O3 source and the SiO2 source comprise FAU zeolite, particularly zeolite Y, more preferably zeolite Y in which the molar ratio of SiO2 to Al2O3 is not greater than 40, not greater than 30, not greater than 20 or even not greater than 10.

[0255] 18. The method according to embodiment 17, wherein an additional SiO2 source is used.

[0256] 19. A method for preparing aluminosilicate zeolites having an AFT framework structure, the method comprising:

[0257] (1) Provide a synthetic mixture containing

[0258] (A) Al2O3 source,

[0259] (B) SiO2 source,

[0260] (C) An organic structure-directing agent source comprising an N,N,N,N',N',N'-hexaethylalkylene diammonium cation as defined in any one of embodiments 1 to 4 above, and

[0261] (2) subject the synthetic mixture to crystallization conditions to form AFT zeolite.

[0262] 20. The method according to embodiment 19, wherein no organic structure directing agent other than the organic structure directing agent containing N,N,N,N',N',N'-hexaethylalkylene diammonium cation is used.

[0263] 21. An aluminosilicate zeolite having an AFT framework structure, which is obtained and / or can be obtained by the method according to any one of embodiments 1 to 20.

[0264] 22. The aluminosilicate zeolite according to embodiment 21 has a molar ratio of silicon dioxide to aluminum oxide of 10 to 25, preferably 11 to 20, and more preferably 11 to 18.

[0265] 23. The aluminosilicate zeolite according to embodiment 21 or 22 has an average crystal size of at most 1 µm.

[0266] 24. An aluminosilicate zeolite having an AFT framework structure, wherein the pores contain a cation of an organic structure directing agent in its original form after synthesis, preferably an N,N,N,N',N',N'-hexaethylalkylene diammonium cation as defined in any one of embodiments 1 to 4 above.

[0267] 25. Use of the aluminosilicate zeolite according to any one of embodiments 21 to 24 in a catalyst for the selective catalytic reduction of nitrogen oxides.

[0268] 26. An SCR catalyst composition comprising an aluminosilicate zeolite having an AFT framework structure and a co-catalyst metal.

[0269] 27. The SCR catalyst composition according to embodiment 26, wherein the co-catalyst metal is selected from transition metals, alkaline earth metals, Sb, Sn and Bi and any combination thereof, preferably comprising Cu and / or Fe, with Cu being the most preferred.

[0270] 28. The SCR catalyst composition according to embodiment 27, wherein the co-catalyst metal is composed of Cu and / or Fe.

[0271] 29. The SCR catalyst composition according to any one of embodiments 26 to 28 above, wherein the co-catalyst metal is located within and / or on the aluminosilicate zeolite having an AFT framework structure, preferably the aluminosilicate zeolite according to any one of embodiments 21 to 23.

[0272] 30. The SCR catalyst composition according to any one of embodiments 26 to 29 above, wherein the co-catalyst metal is present in an amount of 0.1 mol to 1.0 mol, preferably 0.2 mol to 0.7 mol, more preferably 0.3 mol to 0.5 mol per mole of the skeletal aluminum of the aluminosilicate zeolite having the AFT framework structure.

[0273] 31. A catalyst article, which is in the form of an extrusion comprising a catalyst composition or in the form of a bulk material comprising a support coating containing a catalyst composition on a substrate, wherein the catalyst composition is an SCR catalyst composition as defined in any one of embodiments 26 to 30, or wherein the catalyst composition comprises an aluminosilicate zeolite having an AFT framework structure and a metal cocatalyst according to any one of embodiments 21 to 24.

[0274] 32. An exhaust gas treatment system comprising an internal combustion engine and an exhaust gas duct in fluid communication with said internal combustion engine, wherein the catalyst product according to embodiment 31 is present in said exhaust gas duct.

[0275] 33. A method for the selective catalytic reduction of nitrogen oxides, the method comprising:

[0276] (A) Provides an airflow containing nitrogen oxides;

[0277] (B) Contact the gas stream with the SCR catalyst composition according to any one of embodiments 26 to 30 or the catalyst article according to embodiment 31.

[0278] The present invention will be further illustrated by the following embodiments, which illustrate particularly advantageous implementations. Although embodiments are provided to illustrate the invention, they are not intended to limit the invention.

[0279] Example

[0280] Scanning electron microscopy (SEM) measurements were performed using a scanning electron microscope (Hitachi SU1510).

[0281] Using PANalytical X'pert 3 A powder diffractometer (40 kV, 40 mA) was used to measure X-ray powder diffraction (XRD) patterns using CuKα (λ = 1.5406 Å) radiation to collect data in the Bragg-Brentano geometry.

[0282] Example 1: Aluminosilicate AFT zeolite (material A, calcined H-form) was prepared using N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium hydroxide and 1-methyl-1-n-propylpiperidinium hydroxide as organic structure directing agents.

[0283] 463.7 g of an aqueous solution of 1-methyl-1-n-propylpiperidinium hydroxide (12.6 wt%) and 94.2 g of an aqueous solution of N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium hydroxide (22.1 wt%) were mixed with 2679.5 g of DI water, followed by the addition of 174.9 g of sodium hydroxide (99%, solid). After the sodium hydroxide dissolved, 106.5 g of Zeolite HY (SAR=7.2, obtained from Shandong Duoyou) and 836.4 g of Ludox were added. ®AS-40 colloidal silica. After stirring at room temperature for 30 minutes, the synthesized mixture was transferred to an autoclave for crystallization. Crystallization was carried out under static conditions at 150°C for 3 days. After cooling to room temperature, the zeolite product was collected by filtration and dried at 120°C overnight. The synthesized zeolite was then calcined at 550°C for 6 hours to remove the organic structure-directing agent.

[0284] The calcined zeolite was pulverized and subjected to ion exchange in a 10% (w / w) NH₄Cl aqueous solution at a solid / liquid ratio of 1:10. The ion exchange process was carried out at 80°C for 2 hours and repeated twice. After ion exchange, the product was collected by filtration, washed with DI water, dried overnight at 120°C, and calcined at 450°C for 6 hours to obtain calcined H-form zeolite.

[0285] The zeolite has a SiO2 / Al2O3 molar ratio (SAR) of 13.2 (as measured by XRF on the calcined H-form) and a mesopore surface area (MSA) of 23 m². 2 / g, and the zeolite surface area (ZSA) is 527m². 2 / g (as measured for calcined H-form).

[0286] The morphology of zeolite crystals observed from SEM images and the XRD pattern of zeolite are shown in the figures below. Figure 1 and Figure 2 The XRD pattern confirmed that the zeolite possesses a typical AFT framework.

[0287] Example 2: Preparation of aluminosilicate AFT zeolite (Material B, calcined H-form) using N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium hydroxide and tetraethylammonium hydroxide as organic structure directing agents.

[0288] 112.79 g of tetraethylammonium hydroxide aqueous solution (35 wt%) and 742.33 g of N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium hydroxide aqueous solution (22.1 wt%) were mixed with 2429.14 g of DI water, followed by the addition of 148.31 g of sodium hydroxide (99%, solid). After the sodium hydroxide dissolved, 69.93 g of Zeolite HY (SAR=7.2, obtained from Shandong Duoyou) and 884.4 g of Ludox were added. ® AS-40 colloidal silica. After stirring at room temperature for 30 minutes, the synthesized mixture was transferred to an autoclave for crystallization. Crystallization was carried out under static conditions at 150°C for 3 days. After cooling to room temperature, the zeolite product was collected by filtration and dried at 120°C overnight. The synthesized zeolite was then calcined at 550°C for 6 hours to remove the organic structure-directing agent.

[0289] The calcined zeolite was pulverized and subjected to ion exchange in a 10% (w / w) NH₄Cl aqueous solution at a solid / liquid ratio of 1:10. The ion exchange process was carried out at 80°C for 2 hours and repeated twice. After ion exchange, the product was collected by filtration, washed with DI water, dried overnight at 120°C, and calcined at 450°C for 6 hours to obtain calcined H-form zeolite.

[0290] The zeolite has a SiO2 / Al2O3 molar ratio (SAR) of 16.5 (as measured by XRF on the calcined H-form) and a mesopore surface area (MSA) of 37 m². 2 / g, and the zeolite surface area (ZSA) is 484m². 2 / g (as measured for calcined H-form).

[0291] The morphology of zeolite crystals observed from SEM images and the XRD pattern of zeolite are shown in the figures below. Figure 1 and Figure 2 The XRD pattern confirmed that the zeolite possesses a typical AFT framework.

[0292] Example 3: Aluminosilicate AFT zeolite (material C, calcined H-form) was prepared using N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium hydroxide and N,N-dimethyl-N-ethylcyclohexylammonium hydroxide as organic structure directing agents.

[0293] 249.2 g of N,N-dimethyl-N-ethylcyclohexylammonium hydroxide aqueous solution (9.11 wt%) and 453.57 g of N,N,N,N',N',N'-hexaethyl-1,5-pentadiammonium hydroxide aqueous solution (22.1 wt%) were mixed with 2431.51 g of DI water, followed by the addition of 163.51 g of sodium hydroxide (99%, solid) and 9.4 g of sodium sulfate. After the sodium hydroxide and sodium sulfate dissolved, 68.37 g of Zeolite HY (SAR=7.2, obtained from Shandong Duoyou) and 864.6 g of Ludox were added. ® AS-40 colloidal silica. After stirring at room temperature for 30 minutes, the synthesized mixture was transferred to an autoclave for crystallization. Crystallization was carried out under static conditions at 150°C for 3 days. After cooling to room temperature, the zeolite product was collected by filtration and dried at 120°C overnight. The synthesized zeolite was then calcined at 550°C for 6 hours to remove the organic structure-directing agent.

[0294] The calcined zeolite was pulverized and subjected to ion exchange in a 10% (w / w) NH₄Cl aqueous solution at a solid / liquid ratio of 1:10. The ion exchange process was carried out at 80°C for 2 hours and repeated twice. After ion exchange, the product was collected by filtration, washed with DI water, dried overnight at 120°C, and calcined at 450°C for 6 hours to obtain calcined H-form zeolite.

[0295] The zeolite has a SiO2 / Al2O3 molar ratio (SAR) of 17.4 (as measured by XRF on the calcined H-form) and a mesopore surface area (MSA) of 22 m². 2 / g, and the zeolite surface area (ZSA) is 545m². 2 / g (as measured for calcined H-form).

[0296] The morphology of zeolite crystals observed from SEM images and the XRD pattern of zeolite are shown in the figures below. Figure 1 and Figure 2 The XRD pattern confirmed that the zeolite possesses a typical AFT framework.

[0297] Example 4: Preparation of aluminosilicate AFT zeolite (material D, calcined H-form) using N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium hydroxide and 1-methyl-1-n-butyl-piperidinium hydroxide as organic structure directing agents.

[0298] 718.45 g of an aqueous solution of 1-methyl-1-n-butyl-piperidinium hydroxide (9.68 wt%) and 27.83 g of an aqueous solution of N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium hydroxide (22.1 wt%) were mixed with 2441.18 g of DI water, followed by the addition of 172.38 g of sodium hydroxide (99%, solid). After the sodium hydroxide dissolved, 104.90 g of Zeolite HY (SAR=7.2, obtained from Shandong Duoyou) and 824.1 g of Ludox were added. ® AS-40 colloidal silica. After stirring at room temperature for 30 minutes, the synthesized mixture was transferred to an autoclave for crystallization. Crystallization was carried out under static conditions at 150°C for 3 days. After cooling to room temperature, the zeolite product was collected by filtration and dried at 120°C overnight. The synthesized zeolite was then calcined at 550°C for 6 hours to remove the organic structure-directing agent.

[0299] The calcined zeolite was pulverized and subjected to ion exchange in a 10% (w / w) NH₄Cl aqueous solution at a solid / liquid ratio of 1:10. The ion exchange process was carried out at 80°C for 2 hours and repeated twice. After ion exchange, the product was collected by filtration, washed with DI water, dried overnight at 120°C, and calcined at 450°C for 6 hours to obtain calcined H-form zeolite.

[0300] The zeolite has a SiO2 / Al2O3 molar ratio (SAR) of 11.9 (as measured by XRF on the calcined H-form) and a mesopore surface area (MSA) of 9 m². 2 / g, and the zeolite surface area (ZSA) is 542m². 2 / g (as measured for calcined H-form).

[0301] The morphology of zeolite crystals observed from SEM images and the XRD pattern of zeolite are shown in the figures below. Figure 1 and Figure 2 The XRD pattern confirmed that the zeolite possesses a typical AFT framework.

[0302] Example 5: Aluminosilicate AFT zeolite (material E, calcined H-form) was prepared using N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium hydroxide and 1-ethyl-1-n-propylpiperidineonium hydroxide as organic structure directing agents.

[0303] 1191.3 g of an aqueous solution of 1-ethyl-1-n-propylpiperidinium hydroxide (7.9 wt%) and 47.09 g of an aqueous solution of N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium hydroxide (22.1 wt%) were mixed with 1992.65 g of DI water, followed by the addition of 161.51 g of sodium hydroxide (99%, solid) and 14.63 g of sodium sulfate. After the sodium hydroxide and sodium sulfate dissolved, 70.98 g of Zeolite HY (SAR=7.2, obtained from Shandong Duoyou) and 897.6 g of Ludox were added. ® AS-40 colloidal silica. After stirring at room temperature for 30 minutes, the synthesized mixture was transferred to an autoclave for crystallization. Crystallization was carried out under static conditions at 150°C for 3 days. After cooling to room temperature, the zeolite product was collected by filtration and dried at 120°C overnight. The synthesized zeolite was then calcined at 550°C for 6 hours to remove the organic structure-directing agent.

[0304] The calcined zeolite was pulverized and subjected to ion exchange in a 10% (w / w) NH₄Cl aqueous solution at a solid / liquid ratio of 1:10. The ion exchange process was carried out at 80°C for 2 hours and repeated twice. After ion exchange, the product was collected by filtration, washed with DI water, dried overnight at 120°C, and calcined at 450°C for 6 hours to obtain calcined H-form zeolite.

[0305] The zeolite has a SiO2 / Al2O3 molar ratio (SAR) of 15.3 (as measured by XRF on the calcined H-form) and a mesopore surface area (MSA) of 28 m². 2 / g, and the zeolite surface area (ZSA) is 555m².2 / g (as measured for calcined H-form).

[0306] The morphology of zeolite crystals observed from SEM images and the XRD pattern of zeolite are shown in the figures below. Figure 1 and Figure 2 The XRD pattern confirmed that the zeolite possesses a typical AFT framework.

[0307] Example 6: Aluminosilicate AFT zeolite (material F, calcined H-form) was prepared using N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium hydroxide and 1-methyl-1-n-butyl-pyrrolidineonium hydroxide as organic structure directing agents.

[0308] 535.79 g of an aqueous solution of 1-methyl-1-n-butyl-pyrrolidineonium hydroxide (10.09 wt%) and 47.09 g of an aqueous solution of N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium hydroxide (22.1 wt%) were mixed with 2639.82 g of DI water, followed by the addition of 174.96 g of sodium hydroxide (99%, solid). After the sodium hydroxide dissolved, 106.47 g of Zeolite HY (SAR=7.2, obtained from Shandong Duoyou) and 836.4 g of Ludox were added. ® AS-40 colloidal silica. After stirring at room temperature for 30 minutes, the synthesized mixture was transferred to an autoclave for crystallization. Crystallization was carried out under static conditions at 150°C for 3 days. After cooling to room temperature, the zeolite product was collected by filtration and dried at 120°C overnight. The synthesized zeolite was then calcined at 550°C for 6 hours to remove the organic structure-directing agent.

[0309] The calcined zeolite was pulverized and subjected to ion exchange in a 10% (w / w) NH₄Cl aqueous solution at a solid / liquid ratio of 1:10. The ion exchange process was carried out at 80°C for 2 hours and repeated twice. After ion exchange, the product was collected by filtration, washed with DI water, dried overnight at 120°C, and calcined at 450°C for 6 hours to obtain calcined H-form zeolite.

[0310] The zeolite has a SiO2 / Al2O3 molar ratio (SAR) of 11.7 (as measured by XRF on the calcined H-form) and a mesopore surface area (MSA) of 22 m². 2 / g, and the zeolite surface area (ZSA) is 477m². 2 / g (as measured for calcined H-form).

[0311] The morphology of zeolite crystals observed from SEM images and the XRD pattern of zeolite are shown in the figures below. Figure 1 and Figure 2The XRD pattern confirmed that the zeolite possesses a typical AFT framework.

[0312] Example 7: Preparation of aluminosilicate AFT zeolite (material G, calcined H-form) using hexamethylammonium hydroxide and 1-methyl-1-n-propylpiperidinium hydroxide as organic structure directing agents.

[0313] 814.6 g of an aqueous solution of 1-methyl-1-n-propylpiperidinium hydroxide (12.6 wt%) and 80.2 g of an aqueous solution of hexamethylammonium hydroxide (25.3 wt%) were mixed with 2754.5 g of DI water, followed by the addition of 110.8 g of sodium hydroxide (99%, solid). After the sodium hydroxide dissolved, 44.9 g of Zeolite HY (SAR=7.2, obtained from Shandong Duoyou) and 567.6 g of Ludox were added. ® AS-40 colloidal silica. After stirring at room temperature for 30 minutes, the synthesized mixture was transferred to an autoclave for crystallization. Crystallization was carried out under static conditions at 150°C for 3 days. After cooling to room temperature, the zeolite product was collected by filtration and dried at 120°C overnight. The synthesized zeolite was then calcined at 550°C for 6 hours to remove the organic structure-directing agent.

[0314] The calcined zeolite was pulverized and subjected to ion exchange in a 10% (w / w) NH₄Cl aqueous solution at a solid / liquid ratio of 1:10. The ion exchange was carried out at 80°C for 2 hours and repeated twice. After ion exchange, the product was collected by filtration, washed with DI water, dried at 120°C overnight, and calcined at 450°C for 6 hours to obtain calcined H-form zeolite.

[0315] The SiO2 / Al2O3 molar ratio (SAR) of this zeolite is 12.7 (as measured by XRF on the calcined H- form), and the MSA is 41 m. 2 / g, and ZSA is 524m 2 / g (as measured for calcined H-form).

[0316] The morphology of zeolite crystals observed from SEM images and the XRD pattern of zeolite are shown in the figures below. Figure 1 and Figure 2 The XRD pattern confirmed that the zeolite possesses a typical AFT framework.

[0317] Example 8: Preparation of aluminosilicate AFT zeolite using N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium hydroxide as an organic structure directing agent (material H, calcined H-form).

[0318] 1038.7 g of N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium aqueous solution (22.1 wt%) was mixed with 1989.4 g of D.I. water, followed by the addition of 52.38 g of sodium hydroxide (99%, solid). After the sodium hydroxide dissolved, 260.95 g of HY (SAR=7.2, obtained from Shandong Duoyou) and 675.0 g of Ludox were added. ® AS-40 colloidal silica. After stirring at room temperature for 30 minutes, the synthesized mixture was transferred to an autoclave for crystallization. Crystallization was carried out under static conditions at 180°C for 2 days. After cooling to room temperature, the zeolite product was collected by filtration and dried at 120°C overnight. The synthesized zeolite was then calcined at 550°C for 6 hours to remove the organic structure-directing agent.

[0319] The calcined zeolite was pulverized and subjected to ion exchange in a 10% (w / w) NH₄Cl aqueous solution at a solid / liquid ratio of 1:10. The ion exchange process was carried out at 80°C for 2 hours and repeated twice. After ion exchange, the product was collected by filtration, washed with DI water, dried overnight at 120°C, and calcined at 450°C for 6 hours to obtain H-form zeolite.

[0320] The zeolite has a SiO2 / Al2O3 molar ratio (SAR) of 16.2 (as measured by XRF on the calcined H-form) and a mesopore surface area (MSA) of 42 m². 2 / g, and the zeolite surface area (ZSA) is 539m². 2 / g (as measured for calcined H-form).

[0321] The morphology of zeolite crystals observed from SEM images and the XRD pattern of zeolite are shown in the figures below. Figure 1 and Figure 2 The XRD pattern confirmed that the zeolite possesses a typical AFT framework.

[0322] Example 9: Preparation of aluminosilicate AFT zeolite (Material I, calcined H-form) using N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium hydroxide as an organic structure directing agent.

[0323] 1038.7 g of N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium aqueous solution (22.1 wt%) was mixed with 1989.4 g of D.I. water, followed by the addition of 58.44 g of sodium hydroxide (99%, solid). After the sodium hydroxide dissolved, 260.95 g of HY (SAR=7.2, obtained from Shandong Duoyou) and 675.0 g of Ludox were added. ®AS-40 colloidal silica. After stirring at room temperature for 30 minutes, the synthesized mixture was transferred to an autoclave for crystallization. Crystallization was carried out under static conditions at 180°C for 2 days. After cooling to room temperature, the zeolite product was collected by filtration and dried at 120°C overnight. The synthesized zeolite was then calcined at 550°C for 6 hours to remove the organic structure-directing agent.

[0324] The calcined zeolite was pulverized and subjected to ion exchange in a 10% (w / w) NH₄Cl aqueous solution at a solid / liquid ratio of 1:10. The ion exchange process was carried out at 80°C for 2 hours and repeated twice. After ion exchange, the product was collected by filtration, washed with DI water, dried overnight at 120°C, and calcined at 450°C for 6 hours to obtain H-form zeolite.

[0325] The zeolite has a SiO2 / Al2O3 molar ratio (SAR) of 15.6 (as measured by XRF on the calcined H-form) and a mesopore surface area (MSA) of 43 m². 2 / g, and the zeolite surface area (ZSA) is 546m². 2 / g (as measured for calcined H-form).

[0326] The morphology of zeolite crystals observed from SEM images and the XRD pattern of zeolite are shown in the figures below. Figure 1 and Figure 2 The XRD pattern confirmed that the zeolite possesses a typical AFT framework.

[0327] Example 10: Preparation of Cu-supported AFT zeolite material (SCR catalyst)

[0328] The obtained H-form zeolite powder was impregnated with an aqueous solution of copper(II) nitrate by a wet impregnation method and kept in a sealed container at 50°C for 20 hours. The obtained solid was dried and calcined in a furnace at 450°C in air for 5 hours to obtain Cu-loaded zeolite.

[0329] The Cu-loaded AFT zeolite materials prepared according to the above general procedure are summarized in Table 3 below.

[0330] Table 3

[0331]

[0332] Example 11: Catalyst Performance Testing

[0333] To test SCR performance, Cu-loaded zeolite material was slurried with an aqueous zirconium acetate solution, then dried in air at ambient temperature with stirring, and calcined at 550°C for 1 hour to obtain a product containing 5% by weight ZrO2 as a binder. The product was crushed and a powder fraction of 250 to 500 micrometers was used as test samples. A portion of the obtained powder was aged in a 10% by volume steam / air stream at 650°C for 50 hours or at 820°C for 16 hours to provide aged samples.

[0334] Selective catalytic reduction (SCR) tests were conducted in a fixed-bed reactor, where 120 mg of the test sample was loaded together with corundum of the same sieve fraction as a diluent to approximately 1 mL of bed volume, and the tests were performed under the following conditions:

[0335] Gas feed: 500 vppm NO, 500 vppm NH3, 5 v% H2O, 10 v% O2 and balance N2, gas hourly space velocity (GHSV) 80,000 h⁻¹ -1 Or 120,000 h -1 ;

[0336] Temperature: Run 1 - 200℃, 400℃, 575℃ (first run for grading)

[0337] Operating temperatures: 2 - 175℃, 200℃, 225℃, 250℃, 350℃, 450℃, 550℃, 575℃.

[0338] The test results are reported as NOx conversions measured from Run 2 at 200°C and 575°C.

[0339] The results of the test samples in their fresh state, aged at 650°C, and aged at 820°C are summarized in Tables 4, 5, and 6 below, respectively.

[0340] Table 4 Results for fresh Cu-loaded samples

[0341]

[0342] Table 5 Results of Cu-loaded samples aged at 650℃

[0343]

[0344] Table 6 Results of Cu-loaded samples aged at 820℃

[0345]

[0346] It can be seen that the catalyst of the Cu-supported AFT zeolite according to the present invention is effective for selective catalytic reduction (SCR) of nitrogen oxides both in the fresh state and after aging at high temperature.

[0347] Compared to comparative catalysts 4.1 to 4.3 (Example 7) prepared with the same Cu / Al ratio but using a combination of hexamethylammonium and 1-methyl-1-propylpiperidinium organic structure directing agents, the catalysts of the present invention 1.1 to 1.3, 2.1 to 2.3, and 3.1 to 3.3, comprising AFT zeolites prepared using one of N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium diammonium organic structure directing agents and one of tetraalkylammonium and piperidinium organic structure directing agents (Examples 1, 2, and 3), exhibited at least comparable NOx conversions, both in the fresh state and after aging at 650°C. It is well known that the gas hourly space velocity (GHSV) of the gas feed used for SCR performance testing affects NOx conversion. If the same catalyst is tested under otherwise identical conditions, a lower GHSV generally results in a higher NOx conversion. This is why the NOx conversion rate of the catalyst of this invention is assessed to be at least comparable to that of the comparative catalyst in its fresh state and after aging at 650°C, while the catalyst of this invention exhibits a lower NOx conversion rate than the comparative catalyst in some cases.

[0348] Surprisingly, it has been found that after aging at 820°C, the catalyst of this invention exhibits a significantly improved NOx conversion rate compared to the comparative catalyst. Aging at 820°C results in a NOx conversion rate of at least 64%, and even as high as 85%, at 200°C, and at least 66%, and even as high as 96%, at 575°C, compared to 0%, and less than 10%, for the corresponding comparative catalyst. The relatively high SCR activity of the catalyst after aging at 820°C reflects the high stability of AFT zeolite at extremely high temperatures.

Claims

1. A method for preparing aluminosilicate zeolites with an AFT framework structure, the method comprising: (1) Provide a synthetic mixture containing (A) Al2O3 source, (B) SiO2 source, (C1) A first organic structure directing agent source comprising an N,N,N,N',N',N'-hexaethylalkylene diammonium cation represented by formula (IV): (C2H5)3N + (CH2) n N + (C2H5)3 (IV), in, n is an integer from 4 to 7, and (C2) A second organic structure directing agent source, comprising a cation selected from the group consisting of the following: (C2-i) is the quaternary ammonium cation represented by formula (I). (I) in R1, R2, and R3 are independently C1-C8 alkyl groups, and R4 is selected from C1-C8 alkyl groups, C3-C4 alkyl groups, and C4 alkyl groups. 10 cycloalkyl, C6-C 10 Aryl and C7-C 20 Arylalkyl groups, each optionally substituted with one or more hydroxyl groups; and (C2-ii) Piperidineonium cation represented by formula (II), (II) in R a and R b Independently selected from C1-C8 alkyl and C3-C 10 Cycloalkyl groups, or together with the nitrogen atoms bonded to them, form 5- or 6-membered saturated or unsaturated rings, and R c R d R e R f and R g Each is independently H, hydroxyl, or C1-C8 alkyl; or in R a and R e They connect together to form C1-C3 bonds. R b It is a C1-C8 alkyl group, and R c R d R f and R g Each being independently of H, hydroxyl, or C1-C8 alkyl; and (C2-iii) The pyrrolidineonium cation represented by formula (III), (III) in R o and R p Each is independently a C1-C8 alkyl or C3-C 10 cycloalkyl, and R q R r R s and R t Each is independently H, hydroxyl, or C1-C8 alkyl; (2) subject the synthetic mixture to crystallization conditions to form AFT zeolite.

2. The method according to claim 1, wherein the first organic structure directing agent comprises an N,N,N,N',N',N'-hexaethylalkylene diammonium cation represented by formula (IV), wherein n is 5.

3. The method according to claim 1, wherein the N,N,N,N',N',N'-hexaethylalkylene diammonium cation is selected from the group consisting of N,N,N,N',N',N'-hexaethyl-1,4-butanediammonium, N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium, N,N,N,N',N',N'-hexaethyl-1,6-hexanediammonium, N,N,N,N',N',N'-hexaethyl-1,7-heptanediammonium, and any combination thereof.

4. The method according to claim 3, wherein the N,N,N,N',N',N'-hexaethylalkylene diammonium cation is selected from N,N,N,N',N',N'-hexaethyl-1,5-pentanediammonium, N,N,N,N',N',N'-hexaethyl-1,6-hexammonium, N,N,N,N',N',N'-hexaethyl-1,7-heptanediammonium, and any combination thereof.

5. The method according to any one of claims 1 to 4, wherein the quaternary ammonium cation (C2-i) is represented by formula (I), wherein R1, R2 and R3 are independently selected from C1-C4 alkyl groups, and R4 is selected from C1-C4 alkyl, C5-C8 cycloalkyl, phenyl and benzyl groups, each optionally substituted with one or more hydroxyl groups.

6. The method according to claim 5, wherein the quaternary ammonium cation (C2-i) is selected from N,N,N-triethylmethylammonium, N,N,N-trimethyl-2-hydroxyethylammonium, N,N,N-trimethylethylammonium, tetraethylammonium, N,N,N-trimethylcyclopentylammonium, N,N,N-trimethylcyclohexylammonium, N,N,N-trimethylcycloheptylammonium, N,N-dimethyl-N-ethylcyclopentylammonium, N,N-dimethyl-N-ethylcyclohexylammonium, N,N-dimethyl-N-ethylcycloheptylammonium, N, The group consisting of N-diethyl-N-methylcyclopentylammonium, N,N-diethyl-N-methylcyclohexylammonium, N,N-diethyl-N-methylcycloheptylammonium, N,N,N-trimethylphenylammonium, N,N-triethylphenylammonium, N,N-dimethyl-N-ethylphenylammonium, N-methyl-N,N-diethylphenylammonium, N,N,N-trimethylbenzylammonium, N,N,N-triethylbenzylammonium, N,N-dimethyl-N-ethylbenzylammonium, N-methyl-N,N-diethylbenzylammonium, and any combination thereof.

7. The method according to any one of claims 1 to 6, wherein the piperidinium cation (C2-ii) is represented by formula (II), wherein R a and R b Independently selected from C1-C5 alkyl and C5-C 10 Cycloalkyl groups, or those bonded to nitrogen atoms forming 5- or 6-membered saturated or unsaturated rings, R c and R g For H, and R d R e and R f Each of the following is independently H, hydroxyl, or C1-C5 alkyl; or R is wherein a and R e They connect together to form C1-C3 bonds, R b It is a C1-C5 alkyl group, R c and R g For H, and R d and R f Each is independently H, hydroxyl, or C1-C5 alkyl.

8. The method according to claim 1 or 7, wherein the C1-C3 bond is an ethylene bond.

9. The method according to claim 7, wherein the piperidinium cation (C2-ii) is represented by formula (II), wherein R a and R b Each is independently a C1-C5 alkyl group, R c and R g For H, and R d R e and R f Each is independently H, hydroxyl, or C1-C5 alkyl.

10. The method according to claim 9, wherein the piperidinium cation (C2-ii) is represented by formula (II), wherein R a It is a C1-C3 alkyl group, R b It is a C1-C5 alkyl group, R d and R f Each is independently H or C1-C5 alkyl, and R c R e and R g For H.

11. The method of claim 10, wherein the piperidinium cation (C2-ii) is selected from the group consisting of 1,1-dimethylpiperidinium, 1,1,3,5-tetramethylpiperidinium, 1-methyl-1-ethylpiperidinium, 1-methyl-1-n-propylpiperidinium, 1-methyl-1-n-butylpiperidinium, 1,1-diethylpiperidinium, 1-ethyl-1-n-propylpiperidinium, 1-ethyl-1-n-butylpiperidinium, and any combination thereof.

12. The method according to any one of claims 1 to 4, wherein the pyrrolidine-onium cation (C2-iii) is represented by formula (III), wherein R o and R p Each is independently a C1-C5 alkyl group, and R q R r R s and R t Each of the following is independently H, hydroxyl, or C1-C5 alkyl; or R is wherein o and R p One of them is a C1-C5 alkyl group and the other is a C5-C4 alkyl group. 10 Cycloalkyl, and R q R r R s and R t Each is independently H, hydroxyl, or C1-C5 alkyl.

13. The method according to claim 12, wherein the pyrrolidineonium cation (C2-iii) is represented by formula (III), wherein R o and R p Each is independently a C1-C5 alkyl group, and R q R r R s and R t For H.

14. The method of claim 13, wherein the pyrrolidineonium cation (C2-iii) is selected from 1-methyl-1-ethylpyrrolidineonium, 1-methyl-1-n-propylpyrrolidineonium, 1-methyl-1-n-butylpyrrolidineonium, 1,1-diethylpyrrolidineonium, 1-ethyl-1-n-propylpyrrolidineonium, 1-ethyl-1-n-butylpyrrolidineonium, and any combination thereof.

15. The method according to any one of claims 1 to 14, wherein the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of corresponding cations in the range of 10:1 to 1:

30.

16. The method of claim 15, wherein the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of corresponding cations in the range of 5:1 to 1:

30.

17. The method of claim 16, wherein the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of corresponding cations in the range of 4:1 to 1:

25.

18. The method of claim 17, wherein the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of corresponding cations in the range of 3:1 to 1:

25.

19. The method of claim 18, wherein the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of corresponding cations in the range of 3:1 to 1:

20.

20. The method according to any one of claims 1 to 6, wherein the second organic structure directing agent comprises a (C2-i) quaternary ammonium cation, and the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to quaternary ammonium cation in the range of 10:1 to 1:

5.

21. The method of claim 20, wherein the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to quaternary ammonium cation in the range of 5:1 to 1:

1.

22. The method of claim 21, wherein the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to quaternary ammonium cation in the range of 3:1 to 2:

1.

23. The method according to any one of claims 1 to 4 and 7 to 11, wherein the second organic structure directing agent comprises (C2-ii)piperidineonium cation, and the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to piperidinium cation in the range of 1:1 to 1:

30.

24. The method of claim 23, wherein the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to piperidinium cation in the range of 1:2 to 1:

25.

25. The method of claim 24, wherein the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to piperidinium cation in the range of 1:4 to 1:

25.

26. The method of claim 25, wherein the first organic structure directing agent and the second organic structure directing agent are used at a molar ratio of diammonium cation to piperidinium cation in the range of 1:5 to 1:

20.

27. The method according to any one of claims 1 to 4 and 12 to 14, wherein the second organic structure directing agent comprises (C2-iii)pyrrolidine onium cation, and the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to pyrrolidine onium cation in the range of 1:1 to 1:

30.

28. The method of claim 27, wherein the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to pyrrolidine cation in the range of 1:2 to 1:

25.

29. The method of claim 28, wherein the first organic structure directing agent and the second organic structure directing agent are used in a molar ratio of diammonium cation to pyrrolidine onium cation in the range of 1:4 to 1:

20.

30. The method of claim 29, wherein the first organic structure directing agent and the second organic structure directing agent are used at a molar ratio of diammonium cation to pyrrolidine cation in the range of 1:5 to 1:

15.

31. The method according to any one of claims 1 to 30, wherein the Al2O3 source and the SiO2 source comprise FAU zeolite.

32. The method according to claim 31, wherein the Al2O3 source and the SiO2 source comprise zeolite Y.

33. The method according to claim 32, wherein the Al2O3 source and the SiO2 source comprise zeolite Y in which the molar ratio of SiO2 to Al2O3 is not greater than 40.

34. The method according to claim 33, wherein the Al2O3 source and the SiO2 source comprise zeolite Y in which the molar ratio of SiO2 to Al2O3 is not greater than 30.

35. The method according to claim 34, wherein the Al2O3 source and the SiO2 source comprise zeolite Y in which the molar ratio of SiO2 to Al2O3 is not greater than 20.

36. The method according to claim 35, wherein the Al2O3 source and the SiO2 source comprise zeolite Y in which the molar ratio of SiO2 to Al2O3 is not greater than 10.

37. The method according to any one of claims 31 to 36, wherein an additional SiO2 source is used.

38. A method for preparing aluminosilicate zeolites having an AFT framework structure, the method comprising: (1) Provide a synthetic mixture containing (A) Al2O3 source, (B) SiO2 source, (C) An organic structure-directing agent source comprising an N,N,N,N',N',N'-hexaethylalkylene diammonium cation as defined in any one of claims 1 to 4, and (2) subject the synthetic mixture to crystallization conditions to form AFT zeolite.

39. The method of claim 38, wherein no organic structure directing agent other than the organic structure directing agent comprising N,N,N,N',N',N'-hexaethylalkylene diammonium cation is used.

40. An aluminosilicate zeolite having an AFT framework structure, which is obtained and / or can be obtained by the method according to any one of claims 1 to 39.

41. The aluminosilicate zeolite according to claim 40, wherein the molar ratio of silicon dioxide to aluminum oxide is 10 to 25.

42. The aluminosilicate zeolite according to claim 41, wherein the molar ratio of silicon dioxide to aluminum oxide is 11 to 20.

43. The aluminosilicate zeolite according to claim 42, wherein the molar ratio of silicon dioxide to aluminum oxide is 11 to 18.

44. The aluminosilicate zeolite according to any one of claims 40 to 43, wherein the average crystal size is at most 1 µm.

45. An aluminosilicate zeolite having an AFT framework structure, wherein the pores contain a cation of an organic structure directing agent in its original form after synthesis, wherein the cation is an N,N,N,N',N',N'-hexaethylalkylene diammonium cation as defined in any one of claims 1 to 4.

46. ​​Use of the aluminosilicate zeolite according to any one of claims 40 to 45 in a catalyst for the selective catalytic reduction of nitrogen oxides.

47. An SCR catalyst composition comprising an aluminosilicate zeolite having an AFT framework structure as described in any one of claims 40-45 and a co-catalyst metal.

48. The SCR catalyst composition according to claim 47, wherein the co-catalyst metal is selected from transition metals, alkaline earth metals, Sb, Sn and Bi, and any combination thereof.

49. The SCR catalyst composition according to claim 48, wherein the co-catalyst metal is composed of Cu and / or Fe.

50. The SCR catalyst composition according to any one of claims 47 to 49, wherein the co-catalyst metal is located within and / or on the aluminosilicate zeolite having an AFT framework structure.

51. The SCR catalyst composition according to claim 50, wherein the co-catalyst metal is located within and / or on the aluminosilicate zeolite according to any one of claims 40 to 44.

52. The SCR catalyst composition according to any one of claims 47 to 51, wherein the co-catalyst metal is present in an amount of 0.1 to 1.0 mol of skeletal aluminum per mole of the aluminosilicate zeolite having the AFT framework structure.

53. The SCR catalyst composition according to claim 52, wherein the co-catalyst metal is present in an amount of 0.2 mol to 0.7 mol.

54. The SCR catalyst composition according to claim 53, wherein the co-catalyst metal is present in an amount of 0.3 moles to 0.5 moles.

55. A catalytic article, which is in the form of an extrusion comprising a catalyst composition or in the form of a bulk material comprising a support coating containing a catalyst composition on a substrate, wherein the catalyst composition is an SCR catalyst composition as defined in any one of claims 47 to 54, or wherein the catalyst composition comprises an aluminosilicate zeolite having an AFT framework structure and a metal cocatalyst as claimed in any one of claims 40 to 45.

56. An exhaust gas treatment system comprising an internal combustion engine and an exhaust gas duct in fluid communication with the internal combustion engine, wherein the catalyst product according to claim 55 is present in the exhaust gas duct.

57. A method for the selective catalytic reduction of nitrogen oxides, the method comprising: (A) Provides an airflow containing nitrogen oxides; (B) Contact the gas stream with the SCR catalyst composition according to any one of claims 47 to 54 or the catalyst article according to claim 55.

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