CHA-type zeolite and method for synthesizing said zeolite

Abstract

Hydrogen-form chabazite (CHA) zeolite having a SAR of 8-35 and a ratio of XRD peak intensities corresponding to the [2 1 1] and [-1 1 1] reflections of 0.80 or more. CHA zeolite is (i) forming a reaction gel comprising a precursor zeolite (e.g., FER), an organic structure directing agent (OSDA), sodium hydroxide and / or potassium hydroxide, and optionally a silica source; (ii) heating the reaction gel to a temperature suitable for CHA zeolite growth for a period of time suitable for CHA zeolite growth; The composition can be prepared by a method comprising the steps of: Suitable OSDAs for step (i) include N,N,N-trimethyl-1-adamantylammonium, N,N,N-dimethylethylcyclohexylammonium, trimethyl(cyclohexylmethyl)ammonium, tetraethylammonium, N-ethyl-N,N-dimethylcyclohexaneaminium, benzyltrimethylammonium, N,N,N-triethylcyclohexylammonium, N,N,N-trimethylcyclohexylammonium, N,N,N-diethylmethylcyclohexylammonium, trimethylcyclohexylammonium, trimethylphenylammonium, and triethylmethylammonium.

Description

[Technical field]

[0001] The present invention relates to chabazite (CHA) zeolites. More specifically, the present invention relates to hydrogen-form chabazite zeolites having a silica-alumina ratio (SAR) of 8 to 35. The present invention also relates to a method for producing chabazite zeolites, particularly zeolites having a SAR of 8 to 35. The present invention further relates to a catalyst article comprising chabazite zeolites, and a method for treating exhaust gases comprising contacting the exhaust gases with a catalyst article comprising chabazite zeolites. [Background technology]

[0002] Since the discovery of the silica-rich CHA-type zeolite SSZ-13 in 1985 (U.S. Pat. No. 4,544,538), this zeolite has been shown to be particularly effective in preventing NO x NH reduction applications 3 It has been widely studied as an important component of -SCR catalysts and has been produced on an industrial scale. Meanwhile, various improvements on SSZ-13 have also been reported, such as reducing the crystal size to improve the accessibility of the porous space inside the zeolite for catalytic reactions (see US Pat. No. 6,709,644 and US Pat. No. 10,407,314), making larger crystals (US Pat. No. 10,029,247) or crystals with fewer silanol defects (US Pat. No. 10,407,314 and US Pat. No. 10,953,390) to improve the durability of the zeolite under harsh operating conditions, and producing zeolites using alternative OSDAs for cost-effective production (US Pat. No. 8,007,764 and US Pat. No. 10,953,390).

[0003] Global environmental regulations are becoming increasingly stringent. Emission standards in developing countries are catching up with the higher standards required in developed countries. For these reasons, 3-There is still an urgent need for further improvements or better performance of CHA products for use in SCR applications.

[0004] When used as a component material in the preparation of catalysts, the processability of zeolite also has a significant impact on the physical or mechanical properties of the final catalyst product. For example, it is often one of the key factors that affect the uniformity and physical strength of the washcoat layer, as well as the effect on back pressure. Therefore, further improvement of processability is also needed.

[0005] To address these challenges, applicants have discovered novel SSZ-13 type CHA zeolites and synthesis methods for making same, which have substantial advantages over the prior art, including improved processability. In addition, applicants have discovered that the CHA zeolites of the present invention, having the XRD peak intensity ratios defined herein, have low crystal lattice defects and high crystallinity. Summary of the Invention

[0006] One embodiment of the present disclosure relates to a hydrogen-form chabazite (CHA) zeolite having a SAR of 8 to 35 and a ratio of XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections of 0.80 or more.

[0007] Another aspect of the present disclosure is a method for producing chabazite (CHA) zeolite having an SAR of 8 to 35, comprising: (i) forming a reaction gel comprising a precursor zeolite, an organic structure directing agent (OSDA), sodium hydroxide and / or potassium hydroxide, and optionally a silica source; (ii) heating the reaction gel to a temperature suitable for growing the CHA zeolite for a period of time suitable for growing the CHA zeolite; The present invention relates to a method, including the steps of:

[0008] Another aspect of the present disclosure relates to a catalytic article for treating exhaust gases, the catalytic article comprising a hydrogen-form CHA zeolite as described herein.

[0009] Another aspect of the present disclosure relates to a method of treating an exhaust gas comprising contacting the exhaust gas with a catalytic article described herein. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 1. [Diagram 2] FIG. 2 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 2. [Diagram 3] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 3. [Figure 4] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 4. [Diagram 5] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 5. [Figure 6] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 6. [Figure 7] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 7. [Figure 8] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 8. [Figure 9] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 9. [Figure 10] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 10. [Figure 11]FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 11. [Figure 12] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 12. [Figure 13] FIG. 13 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 13. [Figure 14] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 14. [Figure 15] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 15. [Figure 16] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 16. [Figure 17] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 17. [Figure 18] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 18. [Figure 19] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 19. [Figure 19b] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Example 20. [Figure 20] FIG. 2 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Comparative Example A. [Figure 21] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Comparative Example B. [Figure 22] FIG. 1 shows a powder X-ray diffraction (XRD) pattern and an SEM image of the H-type CHA structure prepared in Comparative Example C. [Figure 23] FIG. 2 is a graph showing the NOx conversion rate in Example 1. [Figure 24] FIG. 2 is a graph showing the amount of N2O produced in Example 1. [Diagram 25] FIG. 1 shows the NOx conversion rates of Reference CHA and CHA1. [Figure 26] FIG. 1 shows the amount of N2O produced in the reference CHA and CHA1. [Figure 27] FIG. 4 is a graph showing the NOx conversion rate in Example 2. [Figure 28] FIG. 1 is a graph showing the amount of N2O produced in Example 2. [Figure 29] FIG. 1 shows the NOx conversion rates of Reference CHA and CHA2. [Diagram 30] FIG. 1 shows the amounts of reference CHA and CHA2N2O produced. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A first aspect of the present invention relates to a hydrogen-form chabazite (CHA) zeolite having a SAR of 8 to 35 and a ratio of XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections of 0.80 or more.

[0012] The present disclosure will now be further described. In the following sections, different aspects / embodiments of the present disclosure are defined in more detail. Each aspect / embodiment so defined may be combined with any other aspect / embodiment or aspect / embodiment, unless expressly indicated otherwise. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

[0013] Zeolites are structures formed from alumina and silica, and the SAR determines the reaction sites within the zeolite structure. Small pore zeolites, including CHA-type zeolites, always consist of eight tetrahedral atoms (Si 4+ and Al 3+ These 8-ring pores allow for the entry and exit of larger molecules, which are important for overall catalytic performance, while allowing for the entry and exit of larger molecules into the void space within the crystal. xNO removal x or methanol during its conversion to light olefins. CHA zeolites, as known in the art, are sometimes referred to as zeolites having a CHA framework structure.

[0014] The CHA zeolite according to the present invention is a hydrogen form (H-form) CHA-type zeolite. The term "H-form" CHA zeolite refers to a CHA zeolite having a framework charge substantially balanced by protons. In this form, the CHA zeolite generally has H at the exchange sites. + and a mixture of alkali and / or alkaline earth cations. The H-form of the CHA zeolite can be ≧90%, ≧95%, ≧96%, ≧97%, ≧98%, or ≧99% (by weight) in the H-form. The amount of CHA zeolite in the H-form can vary depending on the particular CHA zeolite batch and the method used to form the CHA zeolite.

[0015] In a preferred embodiment, the CHA zeolite according to the invention is free or substantially free of one or more of the following: fluorine, fluorine-containing compounds, fluorine ions, phosphorus, phosphorus-containing compounds, and phosphorus ions. Preferably, the CHA zeolite according to the invention is free or substantially free of all of the following: fluorine, fluorine-containing compounds, fluorine ions, phosphorus, phosphorus-containing compounds, and phosphorus ions. By "substantially free" it is meant that the zeolite contains less than 0.1%, e.g., less than 0.08%, less than 0.05%, less than 0.03%, less than 0.02%, less than 0.01%, less than 0.005%, less than 0.001% (by weight based on the total weight of the zeolite) of undesirable components.

[0016] The H-type CHA zeolite of the present invention has a ratio of XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections of 0.80 or more. In preferred embodiments, this ratio is 0.85, 0.9, 0.95, 1.0, 1.5 or more. In further embodiments, this ratio is in the range of 0.8-2.5, 0.85-2, 0.9-1.9, 1-1.8, or 1.1-1.7.

[0017] Those skilled in the art would use common general knowledge to calculate the XRD peak intensity ratio of the

[0211] and [-1 1 1] reflections. As is well understood, X-ray diffraction data includes a (2 theta) peak in the range of 24.5-25.5 (±0.2 s-theta degrees) corresponding to the

[0211] reflection and a (2 theta) peak in the range of 15-17 corresponding to the [-1 1 1] reflection. The ratio of the XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections is calculated by calculating the total peak height from the baseline to the apex of the peaks of the

[0211] and [-1 1 1] reflections, and then calculating the ratio of the peak heights of the

[0211] :[-1 1 1] reflections, i.e., by using the following formula:

[0018]

number

[0019] The XRD peak intensities according to the present invention were calculated using copper as the X-ray source. The peak intensities can be calculated using CHA zeolite equilibrated to ambient conditions. For example, ambient conditions can be a temperature of 18-25°C and a humidity of up to 60%, e.g., up to 50%, up to 40%, or up to 30%.

[0020] In one embodiment, the CHA zeolite of the invention has a SAR of 8-17 and a ratio of XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections of 0.95 or more. In further embodiments, the SAR can be 8-17, 9-16, 10-15, 11-14, or 12-13 (e.g., when the ratio of XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections is 0.95 or more). In further embodiments (e.g., when the SAR is 8-17), the ratio of XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections is 0.95 or more, e.g., 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, or 1.5 or more. In further embodiments (eg, when the SAR is between 8 and 17), the ratio of the XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections is in the range of 0.95 to 2.5, 1 to 2.25, 1.1 to 2, 1.2 to 1.9, 1.3 to 1.8, 1.4 to 1.7, or 1.5 to 1.6.

[0021] In one embodiment, the CHA zeolite of the invention has a SAR of 17-24 and a ratio of XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections of 0.85 or more. In further embodiments, the SAR can be 17-24, 18-23, 19-22, or 20-21 (e.g., when the ratio of XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections is 0.85 or more). In further embodiments (e.g., when the SAR is 17-24), the ratio of XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections is 0.85 or more, e.g., 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, or 1.5 or more. In further embodiments (e.g., when the SAR is between 17 and 24), the ratio of the XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections is in the range of 0.85 to 2.5, 0.9 to 2.25, 0.95 to 2, 1 to 1.9, 1.1 to 1.8, 1.25 to 1.75, 1.4 to 1.7, or 1.5 to 1.6.

[0022] In one embodiment, the CHA zeolite of the invention has a SAR of 24-34 and a ratio of XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections of 0.80 or more. In further embodiments, the SAR can be 25-33, 26-32, 27-31, or 28-30 (e.g., when the ratio of XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections is 0.80 or more). In further embodiments (e.g., when the SAR is 24-34), the ratio of XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections is 0.80 or more, e.g., 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, or 1.5 or more. In further embodiments (e.g., when the SAR is between 24 and 34), the ratio of the XRD peak intensities corresponding to the

[0211] and [-1 1 1] reflections is in the range of 0.80 to 2.5, 0.85 to 2.25, 0.9 to 2, 0.95 to 1.9, 1 to 1.8, 1.25 to 1.75, 1.4 to 1.7, or 1.5 to 1.6.

[0023] Preferably, the SAR of the CHA zeolite of the present invention is at most 35, preferably at most 33, preferably at most 30, more preferably at most 28, and even more preferably at most 25. Also, in some embodiments, it is preferred that the SAR of the CHA zeolite is at least 8 or at least 9. In some embodiments, it is preferred that the SAR of the CHA zeolite is 8-35, 9-33, 10-30, 11-28, 12-25, 13-22, 14-21, 15-20, 16-19, or 17-18. In other embodiments, the SAR is preferably 8-33, 8-30, 9-30, 9-28, 9-25, 10-22, or 10-20.

[0024] In further embodiments, the SAR of the CHA zeolite of the present invention is from 16 to 35, preferably from 17 to 30, such as from 17 to 25 or from 17 to 23. In some embodiments, the SAR of the CHA zeolite is preferably from 17 to 25, from 17.5 to 24, from 18 to 23, or from 19 to 22.

[0025] Alone or in combination with any of the desired features described above, the present invention provides a 35m 2 / g, preferably less than 30m 2 / g or less, more preferably 25m 2 In some embodiments, the CHA zeolite can be provided with a mesopore surface area of ​​24 m 2 / g or less, 22m 2 / g or less, 21m 2 / g or less, 20m 2 / g or less, 19m 2 / g or less, 18m 2 / g or less, 17m 2 / g or less, 16m 2 / g or less, 15m 2 / g or less, 14m 2 / g or less, 12m 2 / g or less, or 10m 2 In certain embodiments, the CHA zeolite may have a mesopore surface area of ​​0 to 35 m 2 / g, 1-30m 2 / g, 2~25m 2 / g, or 3 to 24 m 2 / g, 4~22m 2 / g, 5-20m 2 / g, 6-18m 2 / g, 7-17m 2 / g, 8-15m 2 / g, or 9 to 12 m 2 This unique combination of features has been achieved as a result of the unique synthesis methodology described herein. In particular, the inventors have demonstrated that the mesopore surface area of ​​35 m 2 We have identified specific gel formulations that can enable the production of CHA zeolites with the desired SAR described herein along with mesopore surface areas of less than 100 nm / g.

[0026] Mesopore surface area can be measured using any conventional technique in the art, for example, according to the Brunauer-Emmett-Teller (BET) method using Ar or N activated samples at 87K or 77K, respectively. 2The adsorption isotherm of the pore size distribution is determined by the nonlocal density functional theory (NLDFT). The mesopore surface area is calculated by the difference between the apparent BET surface area and the micropore surface area.

[0027] Alone or in combination with any of the desired features described above, the present invention provides a 500-800m 2 / g, 600-800m 2 / g, more preferably 650 to 800m 2 It is possible to provide a CHA zeolite having a BET surface area of ​​100 / g.

[0028] Alone or in combination with any of the desired features described above, the present invention provides 2 / g, 0.22~0.28cm 2 / g, more preferably 0.23 to 0.26 cm 2 It is possible to provide a CHA zeolite having a micropore volume of 10000 / g.

[0029] Preferably, the CHA zeolite has a crystallinity of greater than 90%, for example, greater than 95% or greater than 98%. The CHA zeolite may be substantially free of other crystalline phases, and is typically not an intergrowth of two or more framework types. As used herein, the term "substantially free" means that the zeolite contains less than about 10, 8, 6, 4, 2, or 1 weight percent of the framework impurities named above or all impurities.

[0030] Preferably, the CHA zeolite has granular particles, i.e., the zeolite has a particle morphology in which the zeolite crystals have a three-dimensional shape, as opposed to rod-like particles having a substantially one-dimensional shape, or disk or plate-like particles having a two-dimensional shape. The zeolite preferably has granular particles that include or consist of cubic crystals.

[0031] CHA zeolites preferably comprise uniform, non-agglomerated cubic crystals and / or uniform, non-agglomerated conglomerate crystals. Conglomerate crystals are individual crystals that are tightly bound together to form relatively uniform particles, i.e., not single crystals or individual crystals. Conglomerate crystals may include twins.

[0032] Preferably, the CHA zeolite has an average crystal size (e.g., average longest edge crystal size) of 15 micrometers or less, preferably 12 or 10 micrometers or less. In some embodiments, the CHA zeolite can have an average crystal size (e.g., average longest edge crystal size) of 0.25 to 15 micrometers, preferably 0.5 to 13, 1 to 12, 1.5 to 11 micrometers, 2 to 10 micrometers, 3 to 9.5 micrometers, 4 to 9 micrometers, or 5 to 8 micrometers. In some embodiments, the average crystal size can be 0.25 to 5 micrometers, 0.3 to 4 micrometers, 0.5 to 3 micrometers, 0.6 to 2 micrometers, 0.7 to 1.5 micrometers, or 0.75 to 1 micrometers. Such average crystal sizes can be determined using standard microscopy techniques, such as scanning electron microscopy (SEM). Measurements are made on a statistically significant portion of the zeolite produced.

[0033] In a further embodiment of the present disclosure, there is provided a method for producing a chabazite (CHA) zeolite having an SAR of 8 to 35, comprising the steps of: (i) forming a reaction gel comprising a precursor zeolite, an organic structure directing agent (OSDA), sodium hydroxide and / or potassium hydroxide, and optionally a silica source; (ii) heating the reaction gel to a temperature suitable for growing the CHA zeolite for a period of time suitable for growing the CHA zeolite; The present invention relates to a method, including the steps of:

[0034] It is particularly preferred that the methods described herein are for making the H-type CHA zeolites described herein.

[0035] The inventive method for making the CHA zeolites described herein is an inter-zeolite conversion (IZC) route.

[0036] The precursor zeolite can be selected from ferrierite (FER), faujasite (FAU), MFI, BEA, and LTL. All these zeolitic frameworks are known from the prior art (see, for example, WO2019242618, which discloses FER, BEA, and MFI frameworks, and WO2021101947, which discloses LTL frameworks). Preferably, the precursor zeolite is FER. The precursor zeolite may have a SAR value of 2 to 30, for example 10 to 20. In one embodiment, the precursor zeolite has a SAR value of 16 to 20 or 17 to 19. In another embodiment, the precursor zeolite has a SAR value of 12 to 16. In certain embodiments, the precursor zeolite is FER and has a SAR value of 2-30, 10-20, 12-20, 16-19, or 17-20, such as 16, 17, 18, or 19.

[0037] The precursor zeolite can have any counter ion. For example, the counter ion can be sodium, lithium, cesium, proton (H + ), ammonium, or an organic cation. In a preferred embodiment, the counterion is a sodium counterion.

[0038] In one embodiment, the precursor zeolite is prepared from a reaction gel that does not contain an organic structure directing agent (OSDA). In an alternative embodiment, the ferrierite is prepared from a reaction gel that contains a structure directing agent, preferably an organic structure directing agent (OSDA).

[0039] The applicant has surprisingly found that it is not necessary to prepare the precursor zeolite with an organic structure directing agent (OSDA). This makes the process more efficient and reduces the environmental impact. Although OSDA is typically removed by calcination to prevent impurities in the final product, this energy-intensive step is no longer necessary. This allows the precursor zeolite to be prepared at a much lower cost than precursors that require the use of OSDA. Furthermore, it has been found that precursor zeolites formed without the use of OSDA have properties comparable to, and even better than, precursors formed with OSDA.

[0040] The precursor zeolite can be prepared by a process including: (a) forming a reaction gel comprising an aluminum source, sodium hydroxide and / or potassium hydroxide, and a silica source; (b) heating the reaction gel to a temperature and for a period of time suitable for growth of FER zeolite; and, optionally, (c) filtering and washing the resulting FER zeolite;

[0041] The method of preparing a precursor zeolite can include forming a reaction gel, sometimes simply referred to as a reaction mixture. Such reaction gels are well known in the art of zeolite synthesis. The reaction gel for the method of preparing a precursor zeolite can include an aluminum source, sodium / potassium hydroxide, and a silica source. Examples of aluminum sources include sodium aluminate, aluminum salts, such as aluminum sulfate, aluminum nitrate, aluminum chloride, aluminum hydroxide, aluminum alkoxide, and alumina, preferably one or more of aluminum hydroxide and aluminum sulfate. Examples of silica sources include sodium silicate, potassium silicate, silica gel, silica sol, fumed silica, silicon alkoxide, and precipitated silica, preferably silica sol. Silica sol is a colloidal suspension of silica in water. In other preferred embodiments, the silica source and aluminum source can include the same material, for example, a zeolite, such as silica-alumina or FER framework zeolite. In a preferred embodiment, the reaction gel includes aluminum hydroxide, sodium hydroxide, and silica sol solution.

[0042] In a further embodiment, the reaction gel for preparing the precursor zeolite can further comprise an OSDA. Examples of suitable OSDAs include N,N,N-trialkylcyclohexylammonium derivatives, such as N,N,N-dimethylethylcyclohexylammonium; N,N,N-trialkylbenzylammonium derivatives, such as benzyltrimethylammonium; trialkyl(cyclohexylmethyl)ammonium derivatives, such as trimethyl(cyclohexylmethyl)ammonium; [NR 1 R 2 R 3 R 4 ]+(where R 1 , R 2 ;R 3 and R 4are independently alkyl groups having 1 to 4 carbon atoms, the alkyl groups being optionally substituted with one or more hydroxyl groups, such as tetraethylammonium. In a further embodiment, the OSDA is selected from the list including (e.g., consisting of) N,N,N-trimethyl-1-adamantylammonium, N,N,N-dimethylethylcyclohexylammonium, trimethyl(cyclohexylmethyl)ammonium, and tetraethylammonium. In one embodiment, the reaction gel for preparing the precursor zeolite can further include an OSDA selected from the list including (e.g., consisting of) N,N,N-trimethyl-1-adamantylammonium, N,N,N-dimethylethylcyclohexylammonium, trimethyl(cyclohexylmethyl)ammonium, and tetraethylammonium, benzyltrimethylammonium, N,N,N-triethylcyclohexylammonium, N,N,N-trimethylcyclohexylammonium, N,N,N-diethylmethylcyclohexylammonium, and triethylmethylammonium. In further embodiments, the OSDA may be N,N,N-dimethylethylcyclohexylammonium, used either alone or in combination with further OSDAs (e.g., N,N-trimethyl-1-adamantylammonium and / or benzyltrimethylammonium). In further embodiments, the OSDA may be benzyltrimethylammonium, used either alone or in combination with further OSDAs (e.g., N,N,N-trimethyl-1-adamantylammonium and / or N,N,N-dimethylethylcyclohexylammonium).

[0043] In a preferred embodiment, the reaction gel for preparing the precursor zeolite is a gel that does not contain an organic structure directing agent, i.e., the reaction gel does not contain ODSA. "Does not contain an organic structure directing agent" means that the reaction gel for preparing the precursor zeolite contains less than 1 wt% of an organic structure directing agent, for example, less than 0.9 wt%, less than 0.5 wt%, less than 0.3 wt%, less than 0.2 wt%, less than 0.1 wt%, or less than 0.01 wt%, based on the total weight of the reaction gel. In a preferred embodiment, the reaction gel for preparing the precursor zeolite contains 0 wt% of an organic structure directing agent.

[0044] Heating of the reaction gel to prepare the precursor zeolite is carried out at a temperature and for a period suitable for the growth of FER zeolite. Preferably, the temperature to which the reaction gel is heated for such a suitable period is 100°C to 220°C, more preferably 110°C to 210°C, 120°C to 200°C, 130°C to 190°C, or even 140°C to 180°C. The period during which the reaction gel is heated to a suitable temperature is preferably at least 10 hours, more preferably 20 hours to 5 days, 1 day to 4 days, for example 3 days. It is particularly preferred to heat the reaction gel to these temperatures and hold it at these temperatures for these periods, for example at least 10 hours at a temperature of 100°C to 220°C.

[0045] Preferably, the FER zeolite product obtained by heating the reaction gel at such temperature and for such period of time is recovered by typical vacuum filtration. Preferably, the filtered product is washed with demineralized water (also known as deionized water) used to remove residual mother liquor. Preferably, the zeolite product is washed until the conductivity of the filtrate is less than 0.1 mS. Preferably, the filtered and washed product is then dried at a temperature above 100°C, preferably about 120°C. The FER zeolite product can be filtered by vacuum filtration and washing with demineralized water.

[0046] In a further embodiment, the method for preparing the precursor zeolite can further comprise supporting one or more enhancing metals on the FER zeolite formed in step (b) or step (c). These enhancing metals can be supported on the FER zeolite by incipient wetness, ion exchange, or during preparation of the washcoat slurry.

[0047] The enhancing metal is a non-skeletal metal. As used herein, a "non-skeletal metal" is a metal that is present, preferably as an ionic species, within the molecular sieve pores and / or on at least a portion of the molecular sieve surface, and does not include aluminum and does not include atoms that make up the framework of the molecular sieve. Preferably, the presence of the enhancing metal is at least partially responsible for NO x reduction, NH 3 Oxidation and NO x Facilitate the treatment of exhaust gases, such as those from diesel engines, including processes such as storage.

[0048] The strengthening metals include certain transition metals such as copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), molybdenum (Mo), and zinc (Zn), with copper and / or iron being preferred, and copper being most preferred. Specific strengthening metals are precious metals such as gold (Au) and silver (Ag), and platinum group metals such as platinum (Pt), palladium (Pd), ruthenium (Ru), and rhodium (Rh). Additionally, the strengthening metals may be one or more rare earth metals such as cerium (Ce), praseodymium (Pr), neodymium (Nd), europium (Eu), erbium (Er), gadolinium (Gd), ytterbium (Yb), and yttrium (Y). (Although yttrium can be described as a transition metal, it is referred to herein as a rare earth metal due to its lanthanide-like properties.) Preferred rare earth metals include yttrium and erbium.

[0049] In an alternative embodiment, the FER mixture (including the FER zeolite product and associated mother liquor) obtained from heating the reaction gel at such temperature and for such period of time in step (b) is used as is, i.e., the FER mixture formed from heating the reaction gel at such temperature and for such period of time is used as is without separating the FER zeolite from the mother liquor. In other words, the FER zeolite product and associated mother liquor formed in step (b) can be used as is as precursor zeolite in the method for producing chabazite (CHA) zeolite, making the process more efficient.

[0050] In an alternative embodiment, FER is produced by methods described in the art (e.g., methods described in U.S. Pat. No. 4,650,654 and WO 2020 / 021054).

[0051] The method of the present invention includes a first step of forming a reaction gel, which includes a precursor zeolite, an organic structure directing agent (OSDA), sodium hydroxide and / or potassium hydroxide, and optionally a silica source.

[0052] The synthesis of zeolite crystals is typically carried out using an organic template (also called a structure directing agent or SDA; similarly, the SDA cation is SDA + During crystallization, alumina and silica co-bond to form a crystalline structure around the OSDA. The reactants, reaction conditions, and species of OSDA all influence what type of framework is synthesized. Once sufficient crystallization has occurred, the crystals are removed from the mother liquor and dried. After separating the crystals from the mother liquor, the organic SDA is pyrolyzed and removed from the crystalline structure, thus leaving behind a porous molecular sieve.

[0053] Organic structure directing agents (OSDAs) include N,N,N-trialkylcyclohexylammonium derivatives, such as N,N,N-dimethylethylcyclohexylammonium; N,N,N-trialkylbenzylammonium derivatives, such as benzyltrimethylammonium; trialkyl(cyclohexylmethyl)ammonium derivatives, such as trimethyl(cyclohexylmethyl)ammonium; [NR 1 R 2 R 3 R 4 ]+(where R 1 , R 2 ;R 3 and R 4 are independently alkyl groups having 1 to 4 carbon atoms, the alkyl groups being optionally substituted with one or more hydroxyl groups, such as tetraethylammonium. In a further embodiment, the OSDA is selected from the list including (e.g. consisting of) N,N,N-trimethyl-1-adamantylammonium, N,N,N-dimethylethylcyclohexylammonium, trimethyl(cyclohexylmethyl)ammonium, and tetraethylammonium. In a further embodiment, the OSDA may be N,N,N-dimethylethylcyclohexylammonium, used either alone or in combination with a further OSDA (e.g., N,N-trimethyl-1-adamantylammonium). A further preferred example of an OSDA cation for use in the method is N,N,N-trimethyladamantylammonium (TMAd + Another preferred example of an OSDA cation is N,N,N-dimethylethylcyclohexylammonium (DMECHA +). The OSDA cation is typically associated with an anion, which may be any anion that is not detrimental to the formation of the zeolite. Representative anions include elements from group 17 of the periodic table (e.g., fluoride, chloride, bromide, and iodide), hydroxide, acetate, sulfate, tetrafluoroborate, carboxylate, and the like. In some embodiments, the OSDA anion is selected from hydroxide, halide, sulfate, and / or carbonate. In a preferred embodiment, the anion is a hydroxide anion, i.e., the OSDA is in the hydroxide form. In a further preferred embodiment, the OSDA is selected from TMAd+ and / or DMECHA+, more preferably from TMAdOH and / or DMECHAOH.

[0054] In a preferred embodiment, the OSDA is selected from one or more of the following: N,N,N-trimethyl-1-adamantylammonium, N,N,N-dimethylethylcyclohexylammonium, trimethyl(cyclohexylmethyl)ammonium, tetraethylammonium, benzyltrimethylammonium, N,N,N-triethylcyclohexylammonium, N,N,N-trimethylcyclohexylammonium, N,N,N-diethylmethylcyclohexylammonium, and triethylmethylammonium. In an even more preferred embodiment, the OSDA is selected from one or more of the following: N,N,N-trimethyl-1-adamantylammonium, N,N,N-dimethylethylcyclohexylammonium, and benzyltrimethylammonium. For example, the OSDA can be N,N,N-trimethyl-1-adamantylammonium. The OSDA can be N,N,N-dimethylethylcyclohexylammonium. The OSDA may be benzyltrimethylammonium, preferably in combination with another OSDA (e.g., one selected from N,N,N-trimethyl-1-adamantylammonium, N,N,N-dimethylethylcyclohexylammonium, trimethyl(cyclohexylmethyl)ammonium, tetraethylammonium, benzyltrimethylammonium, N,N,N-triethylcyclohexylammonium, N,N,N-trimethylcyclohexylammonium, and N,N,N-diethylmethylcyclohexylammonium).

[0055] In further embodiments, the OSDA may be N,N,N-dimethylethylcyclohexylammonium, used either alone or in combination with further OSDAs (e.g., N,N-trimethyl-1-adamantylammonium and / or benzyltrimethylammonium). In further embodiments, the OSDA may be benzyltrimethylammonium, used either alone or in combination with further OSDAs (e.g., N,N,N-trimethyl-1-adamantylammonium and / or N,N,N-dimethylethylcyclohexylammonium).

[0056] The OSDA may include trimethyl(cyclohexylmethyl)ammonium, such as the hydroxide, halide, sulfate, and / or carbonate salt of trimethyl(cyclohexylmethyl)ammonium.

[0057] [ka]

[0058] The OSDA may include N,N,N-trimethyl-1-adamantanaminium, such as the hydroxide, halide, sulfate, and / or carbonate salts of N,N,N-trimethyl-1-adamantanaminium.

[0059] [ka]

[0060] The OSDA may include trimethylphenylammonium, such as the hydroxide, halide, sulfate, and / or carbonate salt of trimethylphenylammonium.

[0061] [ka]

[0062] The OSDA may include N-ethyl-N,N-dimethylcyclohexaneaminium, such as the hydroxide, halide, sulfate, and / or carbonate salt of N-ethyl-N,N-dimethylcyclohexaneaminium.

[0063] [ka]

[0064] The OSDA may include trimethylcyclohexylammonium, such as the hydroxide, halide, sulfate, and / or carbonate salt of trimethylcyclohexylammonium.

[0065] [ka]

[0066] The OSDA may include benzyltrimethylammonium, such as the hydroxide, halide, sulfate, and / or carbonate salts of benzyltrimethylammonium.

[0067] [ka]

[0068] The OSDA may include tetraethylammonium, such as the hydroxide, halide, sulfate, or carbonate of tetraethylammonium.

[0069] [ka]

[0070] The reactive gel of the first step of the process of the present invention is formed by adding one or both of sodium hydroxide and potassium hydroxide. When only sodium hydroxide and potassium hydroxide are used to form the reactive gel, sodium hydroxide is preferred.

[0071] The reaction gel of the first step of the method of the present invention may further comprise a silica source. Preferably, the silica source is one or more of sodium silicate, potassium silicate, silica gel, silica sol, fumed silica, silicon alkoxide, and precipitated silica, preferably silica sol. Silica sol is a colloidal suspension of silica in water.

[0072] In some embodiments, the reaction gel of the first step of the method does not include an additional source of alumina.

[0073] As is known in the art, the reaction composition may be any of the SiO 2 particles present in the reaction gel. 2 , Al 2 O 3 , M2 O (wherein M is Na and / or K), OSDA, and H 2 In other words, the reaction gel composition can be described in terms of the equivalent amount of AlO. 2 O 3 Normalized to the molar amount of equivalents (1 mole), the ratio: Al 2 O 3 :aSiO 2 :bOSDA:cM 2 O:dH 2 It can also be described by O. As will be understood, the scale of the reactions and absolute molar numbers may vary.

[0074] In some embodiments, Al 2 O 3 The molar amount of equivalents (i.e., 1 mole of Al provided by the alumina source) 2 O 3 , e.g. 2 moles of Al(OH) 3 ) the gel preferably contains 0.1 to 4 moles of OSDA. 2 O 3 In terms of molar equivalents, the gel contains 0.2 to 2.5 moles of OSDA, more preferably 0.3 to 2 moles of OSDA (i.e., "b" in the gel composition is 0.1 to 4, preferably 0.2 to 2.5, more preferably 0.3 to 2).

[0075] In some embodiments, Al 2 O 3 M for molar equivalents 2 O equivalent, i.e. Na 2 O and K 2 The total amount of O equivalents (one or both can be present) is at least 1 mole, preferably from 1 to 25 moles, more preferably from 5 to 22 moles, more preferably from 6 to 20 moles. Likewise, it can be said that "c" in the gel composition can be any of these ranges or values.

[0076] In some embodiments, Al 2 O 3Relative to the molar amount of equivalents, the gel contains at least 20 molar, preferably 20-60 molar, 20-55 molar, or 20-50 molar amounts of SiO. 2 It is preferred to include equivalents. Similarly, it can be said that "a" in the gel composition can be any of these ranges or values. In some preferred embodiments, about 30 moles of SiO 2 Equivalents are preferred.

[0077] In some embodiments, Al 2 O 3 It is preferred that the gel contains water, and that the water is present in an amount of at least 700 moles, preferably 750-3000 moles, relative to the molar amount of the equivalent. Similarly, it can be said that "d" in the gel composition can be any of these ranges or values. For example, in some embodiments, higher amounts of water are preferred, such as 800-2600 moles, preferably 900-2500 moles.

[0078] In some embodiments, the molar ratio of water to silica in the gel, i.e., H 2 O / SiO 2 The molar ratio is preferably 25 to 50, more preferably 26 to 49, 27 to 48.5, 30 to 48, 32 to 47, or 33 to 46. In a preferred embodiment, H in the gel 2 O / SiO 2 The molar ratio is 26-49, 30-48, or 32-47.

[0079] In some embodiments, the molar ratio of water to silica in the gel, i.e., H 2 O / SiO 2 The molar ratio is preferably 2 to 50, more preferably 3 to 40, 4 to 30, 5 to 20, 6 to 15, or 7 to 12. In a preferred embodiment, H in the gel 2 O / SiO 2 The molar ratio is 5-15, 7-14, or 8-10.

[0080] A particular advantage of the present method is that the inventors have found that the present method does not require the use of seed crystals to form the desired CHA zeolite. Therefore, it is preferred that the reaction gel of the second step does not contain seed crystals (i.e., CHA seed crystals). By "does not contain seed crystals", it is meant that the reaction gel contains less than 1 wt% seed crystals, for example, less than 0.9 wt%, less than 0.5 wt%, less than 0.3 wt%, less than 0.2 wt%, less than 0.1 wt%, or less than 0.01 wt%, based on the total weight of the reaction gel. In a preferred embodiment, the reaction gel contains 0 wt% seed crystals.

[0081] In one embodiment, the reaction gel of the second step does not contain seed crystals (i.e., the reaction gel contains less than 1 wt. % seed crystals, e.g., less than 0.9 wt. %, less than 0.5 wt. %, less than 0.3 wt. %, less than 0.2 wt. %, less than 0.1 wt. %, or less than 0.01 wt. % seed crystals, based on the total weight of the reaction gel), and the OSDA is selected from the list including (e.g., consisting of): N,N,N-trimethyl-1-adamantylammonium, N,N,N-dimethylethylcyclohexylammonium, trimethyl(cyclohexylmethyl)ammonium, benzyltrimethylammonium, and tetraethylammonium.

[0082] In one particularly preferred embodiment of the present invention, the reaction gel of the first step of the method of the present invention consists of a precursor zeolite, an organic structure directing agent (OSDA), sodium hydroxide and / or potassium hydroxide, a silica source, and water, and optionally further sodium and / or potassium salts.

[0083] The method of the present invention further comprises the step of heating the reaction gel of the first step to a temperature suitable for the growth of CHA zeolite for a period suitable for the growth of CHA zeolite. Preferably, the temperature to which the reaction gel is heated for such a suitable period is a temperature between 100°C and 200°C, more preferably between 110°C and 190°C, 120°C and 180°C, 120°C and 170°C, or even between 125°C and 165°C. The period during which the reaction gel is heated to the suitable temperature is preferably at least 10 hours, more preferably between 20 and 60 hours. It is particularly preferred to heat the reaction gel to these temperatures and hold it at these temperatures for these periods, for example at least 10 hours at a temperature between 100°C and 200°C.

[0084] Preferably, the zeolite product obtained by heating the reaction gel at such temperature and for such period of time is recovered by typical vacuum filtration. Preferably, the filtered product is washed with demineralized water (also known as deionized water) used to remove residual mother liquor. Preferably, the zeolite product is washed until the conductivity of the filtrate is less than 0.1 mS. Preferably, the filtered and washed product is then dried at a temperature above 100°C, preferably about 120°C.

[0085] The CHA zeolite product synthesized by the present method may contain one or more non-framework alkali metals and / or alkaline earth metals. These metals are typically introduced into the reaction mixture along with the hydroxide ion source. Examples of such metals include sodium and / or potassium, as well as magnesium, calcium, strontium, barium, lithium, cesium, and rubidium.

[0086] It is usually desirable to remove the alkali metal cation by ion exchange and replace it with hydrogen, ammonium, or any desired metal ion. Thus, the zeolite formed by the method of the present invention may be a Na-type zeolite, a K-type zeolite, or a composite N,K-type, etc., and may be an H-type zeolite, an ammonium-type zeolite, or a metal-exchanged zeolite. In a preferred embodiment, the CHA zeolite formed by the method of the present invention is an H-type zeolite.

[0087] A typical ion exchange technique involves contacting a synthetic zeolite with a solution containing the salt of the desired replacement cation. A wide variety of salts can be used, with chlorides and other halides, nitrates, sulfates, and carbonates being particularly preferred.

[0088] Representative ion exchange techniques are well known in the art. Ion exchange is performed after synthesis and can be performed either before or after calcining the zeolite. After contact with a salt solution of the desired replacing cation, the zeolite is typically washed with water and dried at a temperature ranging from 65° C. to about 315° C., usually from 80° C. to 150° C. After washing, the zeolite can be calcined in an inert gas and / or air at a temperature ranging from about 315° C. to 850° C. for a period ranging from 1 to 48 hours or longer to produce a catalytically active and stable product.

[0089] In a further embodiment, the method for producing chabazite (CHA) zeolite having a SAR of 8 to 35 can further comprise supporting one or more enhancing metals on the CHA zeolite formed in step (ii). These enhancing metals (i.e., the enhancing metals described herein) can be supported on the CHA zeolite by incipient wetness, by ion exchange, or during preparation of the washcoat slurry.

[0090] In a further aspect of the present invention, there is provided a catalytic article for treating exhaust gases, the catalytic article comprising a CHA zeolite as described herein.

[0091] According to yet a further aspect, there is provided a method of treating an exhaust gas comprising contacting the exhaust gas with a catalytic article described herein.

[0092] In a further aspect of the present invention, there is provided a hydrogen form chabazite zeolite having a SAR of 8-35 formed by the methods described herein. EXAMPLES

[0093] General steps: The synthesis gel mixture is prepared by blending the selected ingredients at room temperature according to the synthesis gel composition. The resulting fluid mixture is then transferred to a stirred reactor and sealed. The crystallization step crystallizes the synthesis gel via hydrothermal treatment. The crystallization temperature is between 120°C and 165°C depending on the gel composition. The crystallization is carried out while continuously mixing the synthesis gel by stirring. The amount of time for crystallization is from 10 hours to less than 100 hours.

[0094] After crystallization, the resulting zeolite product is recovered by typical vacuum filtration. In the washing step, residual mother liquor is removed from the solid product using demineralized water until the conductivity of the filtrate is below 0.1 mS. In the drying step, moisture is removed from the filtered solid product by drying in a 120°C oven overnight.

[0095] Synthesis of FER - Example 1: Preparation of FER from OSDA-free synthesis gel First, 14.07 g of aluminum hydroxide (55.8 wt.% Al 2 O 3 ) was dissolved in a mixture of 32.84 g of sodium hydroxide solution (50.0 wt %) and 1221.8 g of demineralized water at room temperature with stirring. Then, 231.3 g of silica sol solution (40.0 wt % SiO 2 ) was added and stirred continuously for 30 minutes. The molar composition of the resulting gel was 20.0SiO 2 -1.00Al 2 O 3 -2.67Na2 O-1000.0H 2 The initial gel was transferred to an autoclave and crystallized at 180° C. for 3 days with stirring. The crystallized solid product was filtered, washed with demineralized water and dried at 120° C. overnight. XRD and XRF measurements showed that a zeolite with FER framework structure and SAR of 17.1 was obtained.

[0096] Synthesis of FER - Example 2: Preparation of FER from OSDA-free synthesis gel First, 11.27 g of aluminum hydroxide (55.8 wt.% Al 2 O 3 ) was dissolved in a mixture of 32.88 g of sodium hydroxide solution (50.0 wt %) and 1224.4 g of demineralized water at room temperature with stirring. Then, 231.5 g of silica sol solution (40.0 wt % SiO 2 ) was added and stirred continuously for 30 min. The molar composition of the resulting gel was 25.0SiO 2 -1.00Al 2 O 3 -3.33Na 2 O-1000.0H 2 The initial gel was transferred to an autoclave and crystallized at 180° C. for 3 days with stirring. The crystallized solid product was filtered, washed with demineralized water and dried overnight at 120° C. XRD and XRF measurements showed that a zeolite with FER framework structure and SAR of 19.7 was obtained.

[0097] Synthesis of FER - Example 3: Preparation of FER from OSDA-free synthesis gel First, 47.5 g of sodium silicate solution (9.00 wt.% Na 2 O, 28.8wt%SiO 2 ) was diluted with 723.5 g of demineralized water while stirring at room temperature. Separately, 11.34 g of sodium aluminate powder (52.7 wt. % Al 2 O 3) was dissolved in 351.0 g of demineralized water with stirring at room temperature to form a clear solution. The latter solution was then added to the former solution with vigorous stirring at room temperature, followed by 166.67 g of silica sol solution (40.0 wt. % SiO 2 ) was added to the mixture. The resulting mixture was stirred continuously for 15 minutes and had a molar composition of 22.8SiO 2 -1.00Al 2 O 3 -2.50Na 2 O-1140.0H 2 The initial synthesis gel was transferred to an autoclave and crystallized at 180°C for 4 days with stirring. The crystallized solid product was filtered, washed with demineralized water, and dried at 120°C overnight. XRD and XRF measurements showed that a zeolite with FER framework structure and SAR of 19.0 was obtained.

[0098] Synthesis of CHA - Example 1: Synthesis of CHA using OSDA-free FER as the aluminum source and N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdOH) as the OSDA 1700 g of initial synthesis gel was prepared by mixing the following components: Synthesis of FER - 109.0 g of OSDA-free FER powder prepared according to Example 1, 1,217.7 g of demineralized water, 13.91 g of sodium hydroxide solution (50.0 wt%), 136.04 g of TMAdOH solution (25.5 wt%), and 223.33 g of sodium silicate solution (28.8 wt% SiO 2 , 9.00 Na 2 The resulting mixture was stirred for 30 min and its molar composition was 30.0SiO 2 -1.00Al 2 O 3 -6.00Na 2 O-2.00TMAdOH-1000.0H 2 The gel was then transferred to an autoclave and crystallized under stirring for 26 h at 150 °C. The crystallized solid product was collected by vacuum filtration, washed with demineralized water, and dried at 120 °C overnight.

[0099] The activated H-form of the synthesized zeolite product was obtained by the following procedure. First, the as-synthesized zeolite dry powder was calcined to burn off the OSDA species. A muffle furnace was used to ramp up to 550°C at 1°C / min and hold at 550°C for 6 hours. The calcined product was then ammonium exchanged twice to remove sodium ions from the zeolite product. Ammonium sulfate was used for the ion exchange at 80°C for 2 hours. The solid product was collected by filtration and washing. The filter cake was dried at 120°C. The obtained NH 4 The H-type zeolite product was converted to an activated H-type zeolite product by calcining again in a muffle furnace at a heating rate of 1°C / min up to 550°C and held at 550°C for 2 hours.

[0100] XRD, SEM, and XRF measurements showed that pure phase CHA was obtained with a SAR of 19.3. Table 1 lists the synthesis batches and the obtained zeolite data.

[0101] Synthesis of CHA - Examples 2-8: Synthesis of CHA by using OSDA-free FER as the aluminum source and N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdOH) as the OSDA These synthetic examples required the same types of starting chemicals as Example 1 and were performed in a similar manner. The specific gel compositions, crystallization conditions, and resulting activated product data are shown or referenced in Tables 1 and 2. In Examples 2-7, the required OSDA-free FER was prepared according to Synthesis of FER - Example 1. In Example 8, the required as-prepared OSDA-free FER was prepared according to Synthesis of FER - Example 2.

[0102] Synthesis of CHA - Example 9: Synthesis of CHA by using pre-crystallized OSDA-free FER batch as aluminum source and N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdOH) as OSDA First, 357.3 g of synthesis gel for OSDA-free FER was prepared and crystallized according to Synthesis of FER - Example 2. Then, to this slurry, which was essentially a mixture of OSDA-free FER and mother liquor with zeolite, the following additional components were added with stirring: 6.16 g of sodium hydroxide solution (50.0 wt%), 24.34 g of TMPdOH solution (25.5 wt%), and 15.32 g of sodium silicate solution (28.8 wt% SiO 2 , 9.00 Na 2 O). The molar composition of the resulting mixture is 30.0SiO 2 -1.00Al 2 O 3 -7.50Na 2 O-2.00TMPdOH-1369.0H 2 The gel was crystallized in an autoclave with stirring for 44 hours at 150° C. The crystallized zeolite product was recovered and processed into an activated form as in Example 1. XRD, SEM, and XRF measurements showed that pure phase CHA was obtained with SAR of 17.6. Tables 1 and 2 also list the synthesis batches and the obtained zeolite data.

[0103] Synthesis of CHA - Examples 10-14: Synthesis of CHA by using pre-crystallized OSDA-free FER batch as aluminum source and N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdOH) as OSDA These synthesis examples required a crystallized OSDA-free FER batch made according to the synthesis of FER - Example 1. Other required starting chemicals were of the same type as those in Example 9. Preparation of CHA synthesis gel, crystallization, conversion of the as-made zeolite to activated form product, and characterization were performed similarly to those in Example 9, see Tables 1 and 2.

[0104] Synthesis of CHA - Example 15: Using OSDA-free FER as the aluminum source, and N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdOH) and N-ethyl,N,N-dimethylcyclohexaneaminium hydroxide (R 2 Synthesis of CHA by using a mixture with These synthetic examples are N-ethyl,N,N-dimethylcyclohexaneaminium hydroxide (R 2 The preparation of CHA synthesis gel, crystallization, conversion of the as-prepared zeolite to activated form product, and characterization were performed similarly to those in Example 1, see Tables 1 and 2.

[0105] Synthesis of CHA - Example 16: Using a pre-crystallized OSDA-free FER batch as the aluminum source, and N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdOH) and N-ethyl,N,N-dimethylcyclohexaneaminium hydroxide (R 2 Synthesis of CHA by using a mixture with These synthetic examples are N-ethyl,N,N-dimethylcyclohexaneaminium hydroxide (R 2 The preparation of CHA synthesis gel, crystallization, conversion of the as-prepared zeolite to activated form product, and characterization were performed similarly to those in Example 9, see Tables 1 and 2.

[0106] Synthesis of CHA - Example 17: Synthesis of CHA by using USY as the aluminum source and N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdOH) as the OSDA 403.2 g of initial synthesis gel was prepared by mixing the following components: 12.4 g of USY (SAR 11.26, Na 2O 0.15%), 304.8 g demineralized water, 4.16 g sodium hydroxide solution (50.0 wt%), 24.4 g TMAdOH solution (25.5 wt%), and 57.4 g sodium silicate solution (28.8 wt% SiO 2 , 9.00 Na 2 The resulting mixture was stirred for 30 min and its molar composition was 30.0SiO 2 -1.00Al 2 O 3 -7.47Na 2 O-2.00TMAdOH-1369.0H 2 The crystallization of this gel, conversion of the as-prepared zeolite to the activated form product, and characterization were carried out similarly to those in Example 1, see Tables 1 and 2.

[0107] Synthesis of CHA - Example 18: Using USY as the aluminum source and N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdOH) and N-ethyl,N,N-dimethylcyclohexaneaminium hydroxide (R 2 Synthesis of CHA by using a mixture with 1500.0 g of initial synthesis gel was prepared by mixing the following components: 26.1 g of USY (SAR 11.26, Na 2 O 0.15%), 1130.2 g demineralized water, 13.9 g sodium hydroxide solution (50.0 wt%), 45.0 g TMAdOH solution (25.5 wt%), 17.5 g R 2 OH solution (53.6%), and 267.3 g of sodium silicate solution (28.8 wt. % SiO 2 , 9.00 Na 2 The resulting mixture was stirred for 30 min and its molar composition was 52.8SiO 2 -1.00Al 2 O 3 -15.43Na 2 O-1.76TMAdOH-1.76R 2 OH-2428.2H 2The crystallization of this gel, conversion of the as-prepared zeolite to the activated form product, and characterization were carried out similarly to those in Example 1, see Tables 1 and 2.

[0108] Synthesis of CHA - Example 19: Using USY as the aluminum source and N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdOH) and N-ethyl,N,N-dimethylcyclohexaneaminium hydroxide (R 2 Synthesis of CHA by using a mixture with 420.0 g of initial synthesis gel was prepared by mixing the following components: 21.6 g of USY (SAR 34.0, Na 2 O 0.00%), 333.5 g demineralized water, 13.44 g sodium hydroxide solution (50.0 wt%), 12.60 g TMAdOH solution (25.5 wt%), 4.91 g R 2 OH solution (53.6%), and 33.88 g of sodium silicate solution (28.8 wt. % SiO 2 , 9.00 Na 2 The resulting mixture was stirred for 30 min and its molar composition was 52.8SiO 2 -1.00Al 2 O 3 -15.43Na 2 O-1.76TMAdOH-1.76R 2 OH-2428.2H 2 The crystallization of this gel, conversion of the as-prepared zeolite to the activated form product, and characterization were carried out similarly to those in Example 1, see Tables 1 and 2.

[0109] Synthesis of CHA - Example 20: Using Na-type OSDA-free FER batch as aluminum source and N-ethyl,N,N-dimethylcyclohexaneaminium hydroxide (R 2 Synthesis of CHA by using OH) 180.0 g of initial synthesis gel was prepared by mixing the following components: Synthesis of FER - 36.07 g of OSDA-free FER powder prepared according to Example 3, 67.2 g of demineralized water, 1.02 g of sodium hydroxide solution (50.0 wt%), 17.30 g of N-ethyl,N,N-dimethylcyclohexaneaminium hydroxide solution (53.6 wt%), and 58.4 g of sodium silicate solution (28.8 wt% SiO 2 , 9.00 Na 2 The resulting mixture was stirred for 30 min and its molar composition was 30.0SiO 2 -1.00Al 2 O 3 -4.70Na 2 O-2.10R 2 OH-250.0H 2 The gel was then transferred to an autoclave and crystallized at 150° C. for 92 hours with stirring. The crystallized zeolite product was collected and processed into an activated form as in Example 1. XRD, SEM, and XRF measurements showed that pure phase CHA was obtained with a SAR of 20.4. Tables 1 and 2 also list the synthesis batches and the resulting zeolite data.

[0110] Synthesis of CHA - Comparative Example A: Synthesis of CHA by using precipitated amorphous aluminosilicate cake as aluminum source and N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdOH) as OSDA First, a sodium silicate solution (28.8 wt. % SiO 2 , 9.00 Na 2An amorphous aluminosilicate wet cake was prepared by blending a 25% sulfuric acid solution (SAR 30.6) with a solution prepared by mixing 25% sulfuric acid solution and aluminum sulfate solution at 80°C. The resulting mixture was stirred for 30 minutes, then filtered and thoroughly washed with demineralized water. 127.4 g of the thus prepared amorphous aluminosilicate cake (SAR 30.6) was then used to prepare 440.0 g of synthesis gel for CHA by mixing with other ingredients including 259.0 g of demineralized water, 18.6 g of sodium hydroxide solution (50.0 wt%), and 35.0 g of TMAdOH solution (25.5 wt%). The resulting gel was stirred for 30 minutes, and its molar composition was found to be 30.6SiO. 2 -1.00Al 2 O 3 -7.50Na 2 O-2.00TMAdOH-1000.0H 2 The crystallization of this gel, conversion of the as-prepared zeolite to the activated form product, and characterization were carried out similarly to those in Example 1, see Tables 1 and 2.

[0111] Synthesis of CHA - Comparative Example B: Synthesis of CHA by using precipitated amorphous aluminosilicate dry powder as aluminum source and N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdOH) as OSDA This synthesis example was similar to Comparative Example A, except that the amorphous aluminosilicate cake was dried overnight at 120° C. and then used to make the CHA synthesis gel, see Tables 1 and 2.

[0112] Synthesis of CHA - Comparative Example C: Synthesis of CHA by using aluminum nitrate as the aluminum source and N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdOH) as the OSDA 403.2 g of initial synthesis gel was prepared by mixing the following components: 6.23 g of aluminum nitrate nonahydrate (98%) solution dissolved in 283.2 g of demineralized water, 20.6 g of sodium hydroxide solution (50.0 wt%), 23.90 g of TMAdOH solution (25.5 wt%), 15.32 g of sodium silicate solution (28.8 wt% SiO 2 , 9.00 Na 2 O), and 53.9 g of silica sol solution (40.0 wt.% SiO 2 The resulting mixture was stirred for 30 min and its molar composition was 52.8SiO 2 -1.00Al 2 O 3 -15.43Na 2 O-3.52TMAdOH-6.00NaNO 3 -2428.2H 2 The crystallization of this gel, conversion of the as-prepared zeolite to the activated form product, and characterization were carried out similarly to those in Example 1, see Tables 1 and 2.

[0113] Evaluation example: Catalyst preparation and NO x Performance measurements for selective catalytic reduction (SCR) of The activated products from CHA synthesis examples #1 and #2 were loaded with 3.5 wt% Cu based on the anhydrous mass of H-form CHA by incipient wetness impregnation with the required amount of copper(II) acetate dissolved in a given amount of demineralized water. The metal-impregnated zeolite was dried at 80°C overnight and then calcined at 550°C in air for 4 hours. Each of the calcined Cu-CHAs was pelletized, crushed, and sieved to collect particles with a size of 40-60 mesh. The Cu-CHAs in particle form thus prepared were fresh Cu-CHA samples. The following aging treatment was applied to each fresh Cu-CHA: 10 vol% H 2 100 h at 650 °C in air flow containing 10% by volume H 2 80 h at 750 °C in air flow containing 10 vol% H 2 At 800 °C for 16 h in a stream of air containing O and 5 vol% H2 900 °C for 5 h in flowing air containing O.

[0114] Fresh and aged samples of each Cu-CHA catalyst were x NH 3 -SCR. For comparison, two commercial CHAs, CHA1 (with SAR of 18.5) and CHA2 (with SAR of 12.8), were evaluated under exactly the same conditions. The amount of each catalyst used in the test was 0.3 g. 500 ppm NO, 550 ppm NH 3 , 350 ppm 10% H 2 O, and 10% O 2 A gas stream containing NH was used. The flow rate of the gas stream used was 2.6 L / min, which is equivalent to 520 L / h per gram of catalyst. The samples were then washed with NH 3 The mixture was heated from room temperature to 150°C under the above gas mixture except for NH. 3 was added to the gas mixture and the sample was held under these conditions for 30 minutes. The temperature was then increased from 150° C. to 500° C. at a rate of 5° C. / min. The downstream gas treated by the catalyst was monitored to determine NO x Conversion rate and N 2 The O selectivity was calculated as shown in Figs.

[0115] Figures 23-30 show that Example 1 is highly active in NO conversion under all test conditions and its overall performance is comparable to CHA1. Example 1 performed better than CHA1 fresh and after light (650°C, 100 hours) and moderate aging (750°C, 80 hours), while CHA1 performed slightly better after moderate and highly severe aging. Example 2 performs comparable to or slightly better than CHA2 in NO conversion under all test conditions.

[0116] [Table 1]

[0117] [Table 2]

Claims

1. A hydrogen-type chabazite (CHA) zeolite having a SAR of 8 to 35 and a ratio of XRD peak intensities corresponding to [2 1 1] and [-1 1 1] reflections of 0.80 or higher.

2. The hydrogen-type CHA zeolite according to claim 1, having 8 to 17 SARs and having a ratio of XRD peak intensities corresponding to [2 1 1] and [-1 1 1] reflections of 0.95 or more.

3. The hydrogen-type CHA zeolite according to claim 1, having 17 to 24 SARs and having a ratio of XRD peak intensities corresponding to [2 1 1] and [-1 1 1] reflections of 0.85 or more.

4. The hydrogen-type CHA zeolite according to claim 1, having 24 to 34 SARs and having a ratio of XRD peak intensities corresponding to [2 1 1] and [-1 1 1] reflections of 0.80 or more.

5. The hydrogen-type CHA zeolite according to any one of claims 1 to 4, wherein the CHA zeolite comprises uniform and unaggregated cubic crystals having an average size of 1 to 10 μm.

6. The hydrogen-type CHA zeolite according to any one of claims 1 to 4, wherein the CHA zeolite comprises uniform and non-aggregated conglomerate crystals.

7. The hydrogen-type CHA zeolite according to any one of claims 1 to 4, wherein the CHA-type zeolite comprises a mixture of (a) uniform and unaggregated cubic crystals having an average size of 1 to 10 μm and (b) uniform and unaggregated conglomerate crystals.

8. The hydrogen-type CHA zeolite according to any one of claims 1 to 4, wherein the zeolite has a crystallinity of more than 90%.

9. A method for producing chabazite (CHA) zeolite having an SAR of 8 to 35, (i) Forming a reaction gel comprising a precursor zeolite, an organic structure directing agent (OSDA), sodium hydroxide and / or potassium hydroxide, and optionally a silica source, (ii) Heating the reaction gel to a temperature suitable for the growth of the CHA zeolite for a period of time suitable for the growth of the CHA zeolite, Methods that include...

10. The method according to claim 9, wherein the precursor zeolite is selected from FER, FAU, MFI, BEA, and LTL.

11. The method according to claim 9 or 10, wherein the precursor zeolite is prepared from a synthetic gel that does not contain an organic structure directing agent, or from a synthetic gel that contains an organic structure directing agent.

12. The aforementioned precursor zeolite (a) Forming a reaction gel containing an aluminum source, sodium hydroxide and / or potassium hydroxide, and a silica source, (b) Heating the reaction gel to a temperature suitable for the growth of FER zeolite for a period of time suitable for the growth of FER zeolite, and optionally, (c) The method according to claim 9 or 10, which is prepared by a process including filtering and washing the obtained FER zeolite.

13. The method according to claim 12, wherein the reaction gel does not contain OSDA.

14. The method according to claim 12, wherein the FER zeolite product and the accompanying mother liquor formed in step (b) are used as is without separating the FER zeolite from the mother liquor.

15. The method according to claim 9 or claim 10, wherein the OSDA used in step (i) is selected from one or more of the following: N,N,N-trimethyl-1-adamantylammonium, N,N,N-dimethylethylcyclohexylammonium, trimethyl(cyclohexylmethyl)ammonium, tetraethylammonium, N-ethyl-N,N-dimethylcyclohexaneaminium, benzyltrimethylammonium, N,N,N-triethylcyclohexylammonium, N,N,N-trimethylcyclohexylammonium, N,N,N-diethylmethylcyclohexylammonium, trimethylcyclohexylammonium, trimethylphenylammonium, and triethylmethylammonium.

16. The method according to claim 9 or 10, wherein the reaction gel in step (i) does not contain CHA seed crystals.

17. The method according to claim 9 or claim 10, wherein the temperature in step (ii) is 100°C to 200°C.

18. The method according to claim 9 or claim 10, wherein the duration of step (ii) is at least 10 hours.

19. The method according to claim 9 or claim 10 for producing the hydrogen-type CHA zeolite described in any one of claims 1 to 4.

20. A catalyst article for treating exhaust gas, comprising a hydrogen-type CHA zeolite according to any one of claims 1 to 4 or a hydrogen-type CHA zeolite obtainable by the method described in claim 9 or claim 10.

21. A method for treating exhaust gas, comprising contacting the exhaust gas with the catalyst article described in claim 20.

22. A hydrogen-type chabazite (CHA) zeolite having a SAR of 8 to 35, formed by the method described in claim 9 or claim 10.

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