Rare earth element containing aluminum-rich zeolitic material

Abstract

The present invention relates to a rare earth element containing zeolitic material having a framework structure selected from the group consisting of AEI, AFT, AFV, AFX, AVL, CHA, EMT, GME, KFI, LEV, LTN, and SFW, including mixtures of two or more thereof, 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 displays an SiO.sub.2:X.sub.2O molar ratio in the range of from 2 to 20, and wherein the zeolitic material contains one or more rare earth elements as counter-ions at the ion exchange sites of the framework structure. Furthermore, the present invention relates to a process for the production of the inventive rare earth element containing zeolitic material as well as to the use of the inventive rare earth element containing zeolitic material.

Claims

1. A zeolitic material, having a framework structure selected from the group consisting of AEI, AFT, AFV, AFX, AVL, CHA, EMT, GME, KFI, LEV, LTN, SFW, and mixtures of two or more thereof, the framework structure comprising SiO.sub.2 and X.sub.2O.sub.3, wherein X is a trivalent element, wherein the zeolitic material has a molar ratio of SiO.sub.2 to X.sub.2O.sub.3 in a range of from 2 to 20, and wherein the zeolitic material comprises one or more rare earth elements RE as counter-ions at ion exchange sites of the framework structure; wherein the one or more rare earth elements RE are selected from the group consisting of La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Sc, and combinations of two or more thereof.

2. The zeolitic material of claim 1, wherein X is selected from the group consisting of Al, B, In, Ga, and combinations of two or more thereof.

3. The zeolitic material of claim 1, wherein an effective ionic radius of the one or more rare earth elements RE is 1.3 angstroms or less.

4. The zeolitic material of claim 1, wherein the one or more rare earth elements RE are comprised in the zeolitic material in an amount in a range of from 0.1 to 7 wt.-% based on 100 wt.-% of SiO.sub.2 comprised in the zeolitic material.

5. The zeolitic material of claim 1, wherein a molar ratio, RE:X.sub.2O.sub.3, of the one or more rare earth elements RE calculated as the respective elements to X203 comprised in the zeolitic material is in a range of from 0.01 to 0.3.

6. The zeolitic material of claim 1, wherein the zeolitic material further comprises one or more transition metal elements M selected from the group consisting of Cr, Fe, Co, Ni, Cu, Zn, Pd, Pt, and combinations of two or more thereof, as counter-ions at ion exchange sites of the framework structure.

7. The zeolitic material of claim 6, wherein the one or more transition metal elements M are comprised in the zeolitic material in an amount in a range of from 0.5 to 10 wt.-% based on 100 wt.-% of SiO.sub.2 comprised in the zeolitic material.

8. The zeolitic material of claim 6, wherein a molar ratio, M:X.sub.2O.sub.3, of the one or more transition metal elements M calculated as the respective elements to X.sub.2O.sub.3 contained in the zeolitic material is in a range of from 0.01 to 1.5.

9. The zeolitic material of claim 1, wherein the framework structure comprises a CHA-type framework structure and the zeolitic material comprises one or more selected from the group consisting of (Ni(deta).sub.2)-UT-6, Chabazite, |Li-Nal|[Al-Si-O]-CHA, DAF-5, LZ-218, Linde D, Linde R, MeAPSO-47, Phi, SAPO-34, SAPO-47, SSZ-13, SSZ-62, UiO-21, Willhendersonite, ZK-14, ZYT-6, and mixtures of two or more thereof.

10. The zeolitic material of claim 1, wherein the zeolitic material is prepared by an organotemplate-free synthetic procedure.

11. The zeolitic material of claim 1, wherein the zeolitic material comprises one or more selected from the group consisting of SSZ-39, SAPO-18, SIZ-8, and mixtures of two or more thereof.

12. The zeolitic material of claim 1, wherein the zeolitic material is in a form chosen from a molecular sieve, an adsorbent, a catalyst or a precursor thereof, and/or a catalyst support or a precursor thereof.

13. A process of producing a zeolitic material having a framework structure selected from the group consisting of AEI, AFT, AFV, AFX, AVL, CHA, EMT, GME, KFI, LEV, LTN, SFW, and mixtures of two or more thereof, the framework structure comprising SiO.sub.2 and X.sub.2O.sub.3, wherein X is a trivalent element, the process comprising: (1) providing a zeolitic material having a framework structure selected from the group consisting of AEI, AFT, AFV, AFX, AVL, CHA, EMT, GME, KFI, LEV, LTN, SFW, and mixtures of two or more thereof, the framework structure comprising SiO.sub.2 and X.sub.2O.sub.3 and the zeolitic material having a molar ratio of SiO.sub.2 to X.sub.2O.sub.3 in a range of from 2 to 20; (2) optionally subjecting the zeolitic material provided in (1) to one or more ion exchange procedures with H+ and/or NH.sub.4.sup.+; and (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; wherein the one or more rare earth elements RE are selected from the group consisting of La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Sc, and combinations of two or more thereof.

14. A zeolitic material, prepared according to the process of claim 13.

Description

DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows the NO conversions obtained according to Example 3 as a function of temperature on the rare-earth ion exchanged Cu-SSZ-13 samples obtained from Example 1 and on Cu-SSZ-13 from Comparative Example 1 in the fresh state, respectively. In the figure, the NO conversion in % is plotted along the ordinate and the temperature in ° C. is plotted along the abscissa. The results for Cu-SSZ-13 with 2.8 wt.-% of Cu is indicated by “.square-solid.”, for Cu,La-SSZ-13 with 3.4 wt.-% of Cu is indicated by “.circle-solid.”, for Cu,Sm-SSZ-13 with 2.3 wt.-% of Cu is indicated by “.diamond-solid.”, for Cu,Ce-SSZ-13 with 1.6 wt.-% of Cu is indicated by “.Math.”, for Cu,Yb-SSZ-13 with 2.7 wt.-% of Cu is indicated by “.box-tangle-solidup.”, for and Cu,Y-SSZ-13 with 2.8 wt.-% of Cu is indicated by “•”.

(2) FIG. 2 shows the NO conversions obtained according to Example 3 as a function of temperature on the rare-earth ion exchanged Cu-SSZ-13 samples obtained from Example 1 and on Cu-SSZ-13 from Comparative Example 1 after hydrothermal aging of the samples, respectively. In the figure, the NO conversion in % is plotted along the ordinate and the temperature in ° C. is plotted along the abscissa. The results for Cu-SSZ-13 with 2.8 wt.-% of Cu is indicated by “.square-solid.”, for Cu,La-SSZ-13 with 3.4 wt.-% of Cu is indicated by “.circle-solid.”, for Cu,Sm-SSZ-13 with 2.3 wt.-% of Cu is indicated by “.diamond-solid.”, for Cu,Ce-SSZ-13 with 1.6 wt.-% of Cu is indicated by “.Math.”, for Cu,Yb-SSZ-13 with 2.7 wt.-% of Cu is indicated by “.box-tangle-solidup.”, for and Cu,Y-SSZ-13 with 2.8 wt.-% of Cu is indicated by “•”.

(3) FIG. 3 shows the low-temperature (150° C. to the right and 175° C. to the left for each sample, respectively) NO conversions obtained according to Example 3 on fresh and hydrothermally aged Al-rich Cu—Y-SSZ-13 catalysts with different amounts of Y as obtained according to Example 2 and Cu-SSZ-13 from Comparative Example 1, respectively. In the figure, the NO conversion in % is plotted along the ordinate. The results are displayed for Cu-SSZ-13 with 2.8 wt.-% of Cu indicated by “2.8Cu-CHA”, Cu,Y-SSZ-13 with 0.8 wt.-% of Y and 2.8 wt.-% of Cu indicated by “2.8Cu-0.8Y-CHA”, Cu,YSSZ-13 with 1.3 wt.-% of Y and 2.8 wt.-% of Cu indicated by “2.8Cu-1.3Y-CHA”, Cu,Y-SSZ-13 with 2.3 wt.-% of Y and 2.5 wt.-% of Cu indicated by “2.8Cu-2.3Y-CHA”, and Cu,Y-SSZ-13 with 2.9 wt.-% of Y and 2.2 wt.-% of Cu indicated by “2.8Cu-2.9Y-CHA”, respectively.

(4) FIG. 4 shows the NO conversions obtained according to Example 3 as a function of temperature on the rare-earth ion exchanged Cu-SSZ-13 samples obtained from Example 2 and on Cu-SSZ-13 from Comparative Example 1 in the fresh state, respectively. In the figure, the NO conversion in % is plotted along the ordinate and the temperature in ° C. is plotted along the abscissa. The results for Cu-SSZ-13 with 2.8 wt.-% of Cu is indicated by “.square-solid.”, for Cu,Y-SSZ-13 with 2.9 wt.-% of Y and 2.2 wt.-% of Cu is indicated by “.diamond-solid.”, for Cu,Y-SSZ-13 with 2.3 wt.-% of Y and 2.5 wt.-% of Cu is indicated by “.Math.”, for Cu,Y-SSZ-13 with 1.3 wt.-% of Y and 2.8 wt.-% of Cu is indicated by “.box-tangle-solidup.”, for and Cu,Y-SSZ-13 with 0.8 wt.-% of Y and 2.8 wt.-% of Cu is indicated by “•”.

(5) FIG. 5 shows the NO conversions obtained according to Example 3 as a function of temperature on the rare-earth ion exchanged Cu-SSZ-13 samples obtained from Example 2 and on Cu-SSZ-13 from Comparative Example 1 after hydrothermal aging of the samples, respectively. In the figure, the NO conversion in % is plotted along the ordinate and the temperature in ° C. is plotted along the abscissa. The results for Cu-SSZ-13 with 2.8 wt.-% of Cu is indicated by “.square-solid.”, for Cu,Y-SSZ-13 with 2.9 wt.-% of Y and 2.2 wt.-% of Cu is indicated by “.diamond-solid.”, for Cu,Y-SSZ-13 with 2.3 wt.-% of Y and 2.5 wt.-% of Cu is indicated by “.Math.”, for Cu,Y-SSZ-13 with 1.3 wt.-% of Y and 2.8 wt.-% of Cu is indicated by “.box-tangle-solidup.”, for and Cu,Y-SSZ-13 with 0.8 wt.-% of Y and 2.8 wt.-% of Cu is indicated by “•”.

(6) FIG. 6 shows the NO conversions obtained according to Example 3 as a function of temperature on the rare-earth ion exchanged Al-rich Cu-SSZ-13 sample obtained from Example 2 with 1.3 wt.-% of Y and 2.8 wt.-% of Cu and on Cu-SSZ-13 from Comparative Example 2 in the fresh and hydrothermally aged states, respectively. In the figure, the NO conversion in % is plotted along the ordinate and the temperature in ° C. is plotted along the abscissa. The results for Cu-SSZ-13 from Comparative Example 2 is indicated by “.box-tangle-solidup.” and for Al-rich Cu,Y-SSZ-13 with 1.3 wt.-% of Y and 2.8 wt.-% of Cu is indicated by “.square-solid.”.

EXAMPLES

(7) Catalyst Characterization

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

Example 1: Preparation of Rare Earth Element Containing Al-Rich Zeolitic Materials Having the CHA Framework Structure Loaded with Copper

(9) Al-rich Na-SSZ-13 zeolite (Si/Al=4) was synthesized from an organotemplate-free approach according to the method disclosed in the examples of WO 2013/068976 A. The Al-rich Na-SSZ-13 was then ion-exchanged twice with 0.1 M NH.sub.4NO.sub.3 at 80° C. to obtain NH.sub.4—SSZ-13. NH.sub.4-SSZ-13 was then exchanged with 0.0015 M rare-earth nitrate solution (La, Sm, Ce, Yb, Y) (pH=3.5) at 130° C. for 12 h. Thereafter, the zeolite slurries were filtered, washed with deionized water and dried at 110° C. for 2 h to obtain SSZ-13 with 1.8 wt.-% of La, SSZ-13 with 2.3 wt.-% of Sm, SSZ-13 with 1.6 wt.-% of Ce, SSZ-13 with 2.7 wt.-% of Yb, and SSZ-13 with 1.3 wt.-% of Y, respectively.

(10) The samples were then ion exchanged with copper. To this effect, copper ions were introduced at about 2.8 wt.-% loading by the ion-exchange of rare earth metal containing SSZ-13 samples using aqueous solution of Cu(NO).sub.3 (pH=3.0) with different concentrations ranging from 0.009 to 0.02 M at 80° C. for 4 h. Thereafter, the zeolite slurries were filtered, washed with deionized water and dried at 110° C. overnight. Subsequently, the samples were calcined in muffle oven at 550° C. for 5 h with a ramping rate of 2° C./min, thus obtaining La-SSZ-13 with 3.4 wt.-% of Cu, Sm-SSZ-13 with 2.3 wt.-% of Cu, Ce-SSZ-13 with 1.6 wt.-% of Cu, Yb-SSZ-13 with 2.7 wt.-% of Cu, and Y-SSZ-13 with 2.8 wt.-% of Cu, respectively.

Example 2: Preparation of Yttrium Containing Al-Rich Zeolitic Materials Having the CHA Framework Structure with Different Loadings of Yttrium

(11) In order to vary the Y content, NH.sub.4—SSZ-13 was exchanged with Y(NO.sub.3).sub.3 aqueous solutions displaying concentrations of yttrium ranging from 0.00075 to 0.01 M at 130° C. for 12 h respectively, for obtaining SSZ-13 displaying loadings of yttrium of 0.8 wt.-%, 1.3 wt.-%, 2.3 wt.-%, and 2.9 wt.-%, respectively.

(12) The samples were then ion exchanged with copper according to the procedure described in Example 1, thus obtaining SSZ-13 with 0.8 wt.-% of Y and 2.8 wt.-% of Cu, SSZ-13 with 1.3 wt. % of Y and 2.8 wt.-% of Cu, SSZ-13 with 2.3 wt.-% of Y and 2.5 wt.-% of Cu, and SSZ-13 with 2.9 wt.-% of Y and 2.2 wt.-% of Cu, respectively.

Comparative Example 1: Preparation of an Al-Rich Zeolitic Material Having the CHA Framework Structure Loaded with Copper

(13) For comparison, an Al-rich Na-SSZ-13 zeolite was synthesized and 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 2.8 wt.-% of copper.

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

(14) For comparison, a conventional commercial Na-SSZ-13 zeolite as obtained from orgaotemplate synthesis (Si/Al=15, BASF, Germany) 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 3: Catalyst Testing in the Selective Catalytic Reduction of NO.SUB.x

(15) NH.sub.3-SCR activity measurements were carried out in a fixed-bed quartz reactor (i.d. 5 mm) with the reactant gas mixture containing 500 ppm NO, 500 ppm NH.sub.3, 10% 02, 5% H.sub.2O, and balance N.sub.2. The total flow rate was 240 ml/min, corresponding to a gas hourly space velocity (GHSV) of 80,000 h.sup.−1. NO, NO.sub.2, and N.sub.2O contents were monitored continuously using a chemiluminescence analyzer (ECO Physics CLD60, Switzerland) and an infrared absorption spectrometer (Sick Maihak S710, 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 the steady state at each temperature.

(16) In the tests, catalyst samples were tested in the fresh and aged states. For aging, the Cu-RE-SSZ-13 catalysts were aged in 10% H.sub.2O/Air at 800° C. for 16 h.

(17) Thus, as may be taken from the results displayed in FIGS. 2, 3, and 5, it has surprisingly been found that for the inventive catalysts a superior NO conversion in SCR may be observed at low temperatures compared to a catalyst sample devoid of a rare earth metal. Furthermore, as may be taken from FIGS. 3 and 5, it has quite unexpectedly been found that for selected inventive catalysts having loadings of yttrium within a certain range, a superior NO conversion is observed in the aged catalysts at high temperatures comparted to a catalyst devoid of a rare earth metal. These findings are particularly surprising since it has been found that in fact low amounts of rare earth metals, and in particular of Y, lead to a substantially higher aging resistance than catalyst samples containing higher amounts thereof.

CITED PRIOR ART DOCUMENTS

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