Rare earth element containing zeolitic material having the AEI framework type and coated monolith substrate

Abstract

A rare earth element containing zeolitic material having an AEI-type framework structure, the framework structure of the zeolitic material comprising SiO.sub.2 and X.sub.2O.sub.3, X being a trivalent element, wherein the zeolitic material contains one or more rare earth elements as counter-ions at the ion exchange sites of the framework structure, and wherein the zeolitic material is obtainable and/or obtained according to a process involving the hydrothermal treatment of the rare earth element containing zeolitic material at a temperature in the range of from 400 to 1,000 C. A coated monolith substrate comprising a rare earth element containing zeolitic material having an AEI-type framework structure, wherein the zeolitic material is supported on the monolith substrate. A process for the production of a coated monolith substrate comprising a rare earth element containing zeolitic material having an AEI-type framework structure.

Claims

1. A coated monolith substrate comprising a rare earth element containing zeolitic material having an AEI-type framework structure, the framework structure of the zeolitic material comprising SiO.sub.2 and X.sub.2O.sub.3, wherein X stands for a trivalent element, wherein the zeolitic material contains one or more rare earth elements as counter-ions at the ion exchange sites of the framework structure, wherein the zeolitic material is supported on the monolith substrate, wherein the zeolitic material displays an SiO.sub.2:X.sub.2O.sub.3 molar ratio in the range of from 6 to 200, and wherein the AEI-type framework structure further comprises one or more transition metal elements M selected from the group consisting of Cr, Fe, Co, Ni, Cu, Zn, Pd, and Pt, including combinations of two or more thereof, as counter-ions at the ion exchange sites of the framework structure, wherein the one or more rare earth elements are Y, and wherein the one or more rare earth elements are contained in the zeolitic material in an amount in the range of from 1.5 to 2.2 wt.-%, based on 100 wt.-% of SiO.sub.2 contained in the zeolitic material.

2. The coated monolith substrate of claim 1, wherein the monolith substrate is a wall-flow monolith substrate or a flow-through monolith substrate.

3. The coated monolith substrate of claim 1, wherein the zeolitic material is supported on the monolith substrate as, or as a component of, a washcoat layer.

4. A rare earth element containing zeolitic material having an AEI-type framework structure, the framework structure of the zeolitic material comprising SiO.sub.2 and X.sub.2O.sub.3, wherein X stands for a trivalent element, wherein the zeolitic material contains one or more rare earth elements as counter-ions at the ion exchange sites of the framework structure, wherein the zeolitic material is obtainable and/or obtained according to a process involving the hydrothermal treatment of the rare earth element containing zeolitic material at a temperature in the range of from 400 to 1,000 C., wherein the zeolitic material displays an SiO.sub.2:X.sub.2O.sub.3 molar ratio in the range of from 6 to 200, and wherein the AEI-type framework structure further comprises one or more transition metal elements M selected from the group consisting of Cr, Fe, Co, Ni, Cu, Zn, Pd, and Pt, including combinations of two or more thereof, as counter-ions at the ion exchange sites of the framework structure, wherein the one or more rare earth elements are Y, and wherein the one or more rare earth elements are contained in the zeolitic material in an amount in the range of from 1.5 to 2.2 wt.-%, based on 100 wt.-% of SiO.sub.2 contained in the zeolitic material.

5. The coated monolith substrate according to claim 1 or the zeolitic material of claim 4, wherein the one or more rare earth elements further comprise La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc, including combinations of two or more thereof.

6. The coated monolith substrate according to claim 1 or the zeolitic material of claim 4, wherein X is selected from the group consisting of Al, B, In, Ga, and combinations of two or more thereof.

7. The zeolitic material of claim 4, wherein the zeolitic material is obtainable and/or obtained according to a process involving the hydrothermal treatment of the rare earth element containing zeolitic material in an atmosphere containing from 1 to 25 vol.-% H.sub.2O.

8. An emissions treatment system for treating exhaust gas from a combustion engine, wherein the emissions treatment system comprises a coated monolith substrate according to claim 1 or the rare earth element containing zeolitic material according to claim 4.

9. A method of using the coated monolith substrate according to claim 1 or the rare earth element containing zeolitic material according to claim 4 as at least one of a molecular sieve, an adsorbent, a catalyst or a precursor thereof, a catalyst support or a precursor thereof, a catalyst for the selective catalytic reduction (SCR) of nitrogen oxides NO.sub.x, an additive in fluid catalytic cracking (FCC) processes, a catalyst in organic conversion reactions, a catalyst in the conversion of alcohols to olefins, or a catalyst in methanol to olefin (MTO) catalysis.

10. A method of using the coated monolith substrate according to claim 1 or the rare earth element containing zeolitic material according to claim 4 for at least one of ion-exchange, storage of CO.sub.2, adsorption of CO.sub.2, oxidation of NH.sub.3, oxidation of NH.sub.3 slip in diesel systems, decomposition of N.sub.2O, selective catalytic reduction (SCR) of nitrogen oxides NO.sub.x, selective catalytic reduction (SCR) of nitrogen oxides NO.sub.x in exhaust gas from a combustion engine, or selective catalytic reduction (SCR) of nitrogen oxides NO.sub.x in exhaust gas from a diesel engine or from a lean burn gasoline engine.

11. A process for the production of a coated monolith substrate comprising a rare earth element containing zeolitic material having an AEI-type framework structure, the framework structure of the zeolitic material comprising SiO.sub.2 and X.sub.2O.sub.3, wherein X stands for a trivalent element, comprising (1) providing a zeolitic material having an AEI-type framework structure, the framework structure of the zeolitic material comprising SiO.sub.2 and X.sub.2O.sub.3; (2) subjecting the zeolitic material provided in (1) to one or more ion exchange procedures with H.sup.+ and/or NH.sub.4.sup.+; (3) subjecting the zeolitic material provided in (1) or obtained in (2) to one or more ion exchange procedures with one or more rare earth elements; (4) subjecting the zeolitic material obtained in (3) to one or more ion exchange procedures with one or more transition metal elements M; and (5) providing the zeolitic material obtained according to (2) (3) or (4) onto a monolith substrate, wherein the zeolitic material is provided as, or as a component of, a washcoat layer onto the monolith substrate, and wherein the zeolitic material provided in (1) displays an SiO.sub.2:X.sub.2O.sub.3 molar ratio in the range of from 6 to 200, and wherein the AEI-type framework structure further comprises one or more transition metal elements M selected from the group consisting of Cr, Fe, Co, Ni, Cu, Zn, Pd, and Pt, including combinations of two or more thereof, as counter-ions at the ion exchange sites of the framework structure, wherein in (3) the one or more rare earth elements are Y, and wherein the one or more rare earth elements are contained in the zeolitic material in an amount in the range of from 1.5 to 2.2 wt.-%, based on 100 wt.-% of SiO.sub.2 contained in the zeolitic material.

12. The process of claim 11, wherein the zeolitic material provided in (1) displays an SiO.sub.2:X.sub.2O.sub.3 molar ratio in the range of from 8 to 100.

13. The process of claim 11, wherein X is selected from the group consisting of Al, B, In, Ga, and combinations of two or more thereof.

14. The process of claim 13, wherein X is Al.

15. The process of claim 11, wherein in (3) the one or more rare earth elements further comprise La, Ce, Sm, and Yb, including combinations of two or more thereof.

16. A coated monolith substrate as obtainable and/or obtained according to the process of claim 11.

17. A process for the production of a coated monolith substrate comprising a rare earth element containing zeolitic material having an AEI-type framework structure, the framework structure of the zeolitic material comprising SiO.sub.2 and X.sub.2O.sub.3, wherein X stands for a trivalent element, comprising (1) providing a zeolitic material having an AEI-type framework structure, the framework structure of the zeolitic material comprising SiO.sub.2 and X.sub.2O.sub.3; (2) subjecting the zeolitic material provided in (1) to one or more ion exchange procedures with one or more rare earth elements; and (3) providing the zeolitic material obtained according to (2) onto a monolith substrate, wherein the zeolitic material provided in (1) displays an SiO.sub.2:X.sub.2O.sub.3 molar ratio in the range of from 6 to 200, and wherein the AEI-type framework structure further comprises one or more transition metal elements M selected from the group consisting of Cr, Fe, Co, Ni, Cu, Zn, Pd, and Pt, including combinations of two or more thereof, as counter-ions at the ion exchange sites of the framework structure, wherein in (2) the one or more rare earth elements are Y, and wherein the one or more rare earth elements are contained in the zeolitic material in an amount in the range of from 1.5 to 2.2 wt.-%, based on 100 wt.-% of SiO.sub.2 contained in the zeolitic material.

18. The process of claim 17, wherein the zeolitic material provided in (1) displays an SiO.sub.2:X.sub.2O.sub.3 molar ratio in the range of from 8 to 100, or wherein X is selected from the group consisting of Al, B, In, Ga, and combinations of two or more thereof, or wherein in (2) the one or more rare earth elements further comprise are selected from the group consisting of Y, La, Ce, Sm, and Yb, including combinations of two or more thereof.

19. The process of claim 18, wherein X is Al.

Description

DESCRIPTION OF THE FIGURES

(1) FIG. 1 displays NO conversions as a function of temperature on fresh and 800 C. aged CuY-AEI and Cu-CHA catalysts from Example 1 and Comparative Example 2, respectively, as tested in Example 2. Reaction Conditions: 500 ppm NO, 500 ppm NH.sub.3, 10% O.sub.2, 5% H.sub.2O, balance N.sub.2; GHSV=80,000 h.sup.1.

(2) FIG. 2 displays NO conversions (a) and N.sub.2O yields (b) on 900 C. aged CuY-AEI and Cu-CHA catalysts from Example 1 and Comparative Example 2, respectively, as tested in Example 2. Reaction Conditions: 500 ppm NO, 500 ppm NH.sub.3, 10% O.sub.2, 5% H.sub.2O, balance N.sub.2; GHSV=80,000 h.sup.1.

(3) FIG. 3 XRD patterns of fresh and 900 C. aged CuY-AEI and Cu-CHA catalysts from Example 1 and Comparative Example 2, respectively, as aged in Example 2.

(4) FIG. 4 .sup.27Al MAS NMR spectra of fresh and 900 C. aged CuY-AEI and Cu-CHA catalysts from Example 1 and Comparative Example 2, respectively, as aged in Example 2.

(5) FIG. 5 displays NO conversions as a function of time at 250 C. on Cu-AEI, CuY-AEI and Cu-CHA catalysts from Comparative Example 1, Example 1, and Comparative Example 2, respectively, as tested in Example 2 in the presence of SO.sub.2. Reaction conditions: 500 ppm NO, 500 ppm NH.sub.3, 10% 02, 5% CO.sub.2, 5% H.sub.2O, 50 ppm SO.sub.2, GHSV=80,000 h.sup.1.

EXPERIMENTAL SECTION

(6) Catalyst Characterization

Reference Example 1: Determination of Cation Contents in the Catalyst Materials

(7) The cation contents in the catalysts were determined by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES, Optima 2000 DV, USA).

Reference Example 2: Determination of the X-Ray Diffraction Patterns of the Zeolitic Materials

(8) X-ray diffraction (XRD) analysis was carried out on an X-ray diffractometer (Rigaku D-Max Rotaflex) using Cu K radiation (=1.5418 ) in the 2 range of 2-50 and scan rate of 5/min. UV-Vis diffuse reflectance spectra were recorded in the range of 190-800 nm on JASCO V550 spectrometer.

Reference Example 3: Determination of the .SUP.27.Al MAS NMR Spectra of the Zeolitic Materials

(9) All solid-state NMR experiments were performed. .sup.27Al MAS NMR spectra were acquired at 130.2 MHz on the Agilent DD2-500 MHz spectrometer using a 4 mm MAS NMR probe with a spinning rate of 14 kHz. .sup.27Al MAS NMR spectra were accumulated for 400 scans with /12 flip angle, and 1 s pulse delay. Chemical shifts were referenced to 1% Al(NO.sub.3).sub.3 aqueous solution.

Reference Example 4: Preparation of NaSSZ-39

a) Providing the N,N-diethyl-cis-2,6-dimethylpiperidinium hydroxide (DMPOH)

(10) Materials Used:

(11) TABLE-US-00001 cis-2,6-dimethylpiperidine (Sigma-Aldrich Reagent Co., Ltd.) 40 g Iodoethane (99%, Aladdin Chemical Co., Ltd.) 222 g Potassium bicarbonate (KHCO.sub.3, AR, 99.5%, 71 g Sinopharm Chemical Reagent Co., Ltd.) Methanol (Sinopharm Chemical Reagent Co., Ltd.) 110 g Diethyl ether (AR, 99.5%, Sinopharm Chemical Reagent 1,000 g Co., Ltd.) Anion-exchange resin (Amberlite IRN-78, OH-form, 300 g Thermofisher)

(12) N,N-diethyl-cis-2,6-dimethylpiperidine iodide was synthesized by reacting cis-2,6-dimethylpiperidine, iodoethane, and an excess of KHCO.sub.3 in the presence of methanol solvent, followed by refluxing at 70 C. for 4 days. The KHCO.sub.3 was filtered and then the solvent and the excess of iodoethane was removed by rotary evaporation. The product was washed with ether. The molecular structure was verified using .sup.1H and .sup.13C nuclear magnetic resonance (NMR). The product was converted from the iodide form to the hydroxide form (denoted as DMPOH) using an anion exchange resin.

b) Preparation of a Zeolitic Material Having Framework Type AEI

(13) Materials Used:

(14) TABLE-US-00002 Sodium aluminate (NaAlO.sub.2, AR, 99%, Sinopharm Chemical 0.038 g Reagent Co., Ltd.) Deionized water 4.4 g DMPOH solution (according to a) above; 0.23M in water 10 g Sodium hydroxide (NaOH, AR, 96%, Sinopharm Chemical 0.55 g Reagent Co., Ltd.) Colloidal silica (40 weight-% SiO.sub.2 in water, Sigma-Aldrich 2.95 g Reagent Co., Ltd.) AEI seeds (prepared according to Comparative Example 1 0.02 g hereinabove)

(15) NaAlO.sub.2 was dissolved in deionized water and the DMPOH solution was then added. After stirring at room temperature for 2 h, NaOH was introduced, followed by addition of the colloidal silica and the AEI seeds. This provided a synthesis mixture with the following molar composition: 1.0 SiO.sub.2:0.0083 Al.sub.2O.sub.3:0.35 Na.sub.2O:0.12 DMPOH:44 H.sub.2O:0.017 AEI zeolite seeds

(16) The ratio of SiO.sub.2:Al.sub.2O.sub.3 was 120:1. After stirring for 10 min at room temperature, said synthesis mixture was transferred into a Teflon-lined autoclave oven and crystallized at 140 C. for 3 days. After filtering, washing, drying, and calcining at 550 C. for 4 h, the product was obtained, which was designated as a zeolitic material (Si/Al=10) having framework type AEI, as shown by XRD analysis.

Example 1: Preparation of an Yttrium Containing Zeolitic Material Having the AEI Framework Structure Loaded with Copper

(17) NaSSZ-39 with AEI structure as obtained from Reference Example 4 was exchanged to NH.sub.4-form with 0.5 M NH.sub.4NO.sub.3 aqueous solution at 80 C., then filtered, dried and calcined in flow air to get H-AEI. H-AEI was exchanged with 0.002 M Y(NO.sub.3).sub.3 aqueous solution (pH=3.5) at 180 C. for 12 h. Thereafter, the zeolite slurry was filtered, washed with deionized water and dried at 110 C. Cu was introduced by the ion-exchange of Y-AEI with 0.016 M aqueous solution of Cu(CH.sub.3COO).sub.2 at 50 C. for 4 h. Thereafter, the zeolite slurry was filtered, washed with deionized water, and dried at 110 C. for 12 h. Subsequently, the sample was calcined in muffle oven at 550 C. for 5 h with a ramping rate of 2 C./min.

(18) The resulting catalyst was denoted as 2.3 Cu-1.8 Y-AEI, indicating the Cu and Y contents as determined by ICP, respectively.

Comparative Example 1: Preparation of a Commercial Zeolitic Material Having the AEI Framework Structure Loaded with Copper

(19) NaSSZ-39 with AEI structure as obtained from Reference Example 4 was exchanged to NH.sub.4-form with 0.5 M NH.sub.4NO.sub.3 aqueous solution at 80 C., then filtered, dried and calcined in flow air to get H-AEI. Cu was introduced by the ion-exchange of H-AEI with 0.01M aqueous solution of Cu(CH.sub.3COO).sub.2 at 50 C. for 4 h. Thereafter, the zeolite slurry was filtered, washed with deionized water, and dried at 110 C. for 12 h. Subsequently, the sample was calcined in muffle oven at 550 C. for 5 h with a ramping rate of 2 C./min.

(20) The resulting catalyst was denoted as 3.0Cu-AEI, indicating the Cu content as determined by ICP.

Comparative Example 2: Preparation of a Commercial Zeolitic Material Having the CHA Framework Structure Loaded with Copper

(21) For comparison, a conventional commercial NaSSZ-13 zeolite as obtained from organotemplate synthesis (Si/Al=15; prepared according to the procedure described in example 1 of WO 2015/185625 A) was successively ion exchanged with ammonium and copper according to the procedure in Example 1, yet was not loaded with a rare earth element prior to loading with copper for obtaining SSZ-13 with 2.5 wt.-% of copper.

Example 2: Catalyst Testing in the Selective Catalytic Reduction of NO.SUB.x

(22) Prior to reaction tests, all the catalyst powders were pelletized at 2 MPa, then crushed and sieved to obtain grains between 40 and 60 meshes.

(23) In the tests, catalyst samples were tested in the fresh and aged states. For aging, the respective samples were hydrothermally aged at 800 C. in 10% H.sub.2O/air for 16 h. Alternatively, the respective samples were aged at 900 C. in 10% H.sub.2O/air for 7 h.

(24) NH.sub.3SCR activity measurements were carried out in a micro fixed-bed quartz reactor (i.d. 6 mm) with 8 channel-gas feeding system for mixing NO, NH.sub.3, C.sub.3H.sub.6, O.sub.2, SO.sub.2 CO.sub.2, H.sub.2O, and N.sub.2 at desired concentration. Typically, the reactant gas mixture contains 500 ppm NO, 500 ppm NH.sub.3, 10% O.sub.2, 5% H.sub.2O, 50 ppm SO.sub.2 (when required) and balance N.sub.2. The total flow rate was 240 ml/min, corresponding to a gas hourly space velocity (GHSV) of about 80,000 h.sup.1. NO, NO.sub.2, and N.sub.2O contents were monitored continuously using a chemiluminescence analyzer (ECO Physics, Switzerland) and an infrared absorption spectrometer (Sick Maihak, Germany). To avoid errors caused by the conversion of ammonia in the analyzer, an ammonia trap containing phosphoric acid solution was installed upstream. All data were obtained when the SCR reaction reached a steady state at each temperature.

(25) Hydrothermal Stability of Cu-AEI and CuY-AEI

(26) Fresh Cu-AEI from Comparative Example 1 shows better SCR performances than the benchmark Cu-CHA from Comparative Example 2 at lower and higher reaction temperatures (see FIG. 1). NO conversion on Cu-AEI is over 90% in the whole reaction temperature window. Addition of rare-earth Y into Cu-AEI decreases the NO conversions at lower and higher temperatures, yet Cu-AEI still exhibits higher NO conversions than the benchmark Cu-CHA at high temperatures. After aging at 800 C., aged Cu-AEI displays lower SCR activities at low-temperatures. However, aged 2.3 Cu-1.8 Y-AEI shows better performances than the benchmark Cu-CHA throughout.

(27) Based on the results displayed in FIG. 1, it must be noted that Cu-AEI performs far better than Cu-CHA both prior to and after aging. Accordingly, as opposed to Cu-CHA, no need whatsoever for hydrothermal stabilization in Cu-AEI when considering its performance in the conversion of NO in NH.sub.3SCR.

(28) As may be taken from FIG. 2, however, after hydrothermal aging at 900 C., the NO conversion over Cu-AEI massively drops compared to Cu-CHA. As may be taken form FIGS. 3 and 4 comparing the X-ray diffraction pattern of Cu-CHA and Cu-AEI in the fresh state and after hydrothermal aging at 900 C., said drop in activity is due to a collapse in the framework structure of the material. This finding is highly unexpected in view of the high thermal stability of the material compared to Cu-CHA displayed in FIG. 1, even after extensive hydrothermal aging at 800 C.

(29) Quite surprisingly, however, it has been found that by including yttrium in the material according to Example 1, said sudden collapse from hydrothermal aging may be prevented. Thus, as may be taken from the X-ray diffraction patterns in FIG. 3, the CuY-AEI material from Example 1 maintains its structure even after hydrothermal aging under the same conditions at 900 C. As may be taken from .sup.27Al MAS NMR spectra in FIG. 4, after severe hydrothermal aging at 900 C., framework Al can still be maintained in CuY-AEI, but no framework Al in Cu-AEI. Furthermore, as may be taken from FIG. 2, said material displays a high NO conversion activity, which is clearly superior to Cu-CHA at high temperatures. Thus, it has unexpectedly been found that although contrary to Cu-CHA, the catalytic activity of Cu-AEI does not suffer thermal degradation even after hydrothermal aging at high temperatures such as 800 C., the collapse of the framework structure at yet higher temperatures such as at 900 C. may effectively be prevented by ion exchanging yttrium into the zeolitic material.

(30) SO.sub.2-Tolerance of CuY-AEI

(31) FIG. 5 displays the effect of SO.sub.2 poisoning on Cu-AEI, CuY-AEI and Cu-CHA catalysts from Comparative Example 1, Example 1, and Comparative Example 2, respectively, as tested in Example 2 in the presence of SO.sub.2. From FIG. 5 it is clear that in the presence of SO.sub.2 at 250 C., CuY-AEI has the best NO conversion of 76% after running 22 h among the test catalysts. The SO.sub.2-resistance capability is: 2.3 Cu-1.8 Y-AEI>Cu-AEI>2.5Cu-CHA (FR0287).

(32) In particular, however, it has quite surprisingly been found that at the beginning of the testing procedure, the CuY-AEI sample shows no inhibition whatsoever during an over an hour of testing, whereas all of the other samples display a net decrease in catalytic activity due to SO.sub.2 poisoning already shortly after the beginning of the addition of SO.sub.s to the gas stream (see encircled area in FIG. 5). Accordingly, it has quite unexpectedly been found that the effects of SO.sub.2 poisoning are substantially delayed when using CuY-AEI in NH.sub.3SCR.

CITED PRIOR ART

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