A PROCESS FOR PREPARING A ZEOLITIC MATERIAL HAVING FRAMEWORK TYPE AEI

Abstract

A process for preparing a zeolitic material having framework type AEI and having a framework structure which comprises a tetravalent element Y, a trivalent element X, and oxygen, said process comprising (i) providing a zeolitic material having framework type CHA and having a framework structure comprising the tetravalent element Y, the trivalent element X, and oxygen; (ii) preparing a synthesis mixture comprising the zeolitic material provided in (i), water, a source of the tetravalent element Y other than the zeolitic material provided in (i), and an AEI framework structure directing agent; (iii) subjecting the synthesis mixture prepared in (ii) to hydrothermal synthesis conditions comprising heating the synthesis mixture to a temperature in the range of from 100 to 200 C. and keeping the synthesis mixture at a temperature in this range under autogenous pressure, obtaining the zeolitic material having framework type AEI; wherein Y is one or more of Si, Ge, Sn, Ti, Zr; wherein X is one or more of Al, B, Ga, In; wherein in the framework structure of the zeolitic material provided in (i), the molar ratio Y:X, calculated as YO.sub.2:X.sub.2O.sub.3, is at most 20:1.

Claims

1. A process for preparing a zeolitic material having framework type AEI and having a framework structure which comprises a tetravalent element Y, a trivalent element X. and oxygen, said process comprising (i) providing a zeolitic material having framework type CHA and having a framework structure comprising the tetravalent element Y, the trivalent element X, and oxygen; (ii) preparing a synthesis mixture comprising the zeolitic material provided in (i), water, a source of the tetravalent element Y other than the zeolitic material provided in (i), and an AEI framework structure directing agent; (iii) subjecting the synthesis mixture prepared in (ii) to hydrothermal synthesis conditions comprising heating the synthesis mixture to a temperature in the range of from 100 to 200 C. and keeping the synthesis mixture at a temperature in this range under autogenous pressure, obtaining the zeolitic material having framework type AEI; wherein Y is one or more selected from the group consisting of Si, Ge, Sn, Ti, and Zr; wherein X is one or more selected from the group consisting of Al, B, Ga, and In; and wherein in the framework structure of the zeolitic material provided in (i), the molar ratio Y:X, calculated as YO.sub.2:X.sub.2O.sub.3, is at most 20:1.

2. The process of claim 1, wherein Y is Si and Xis Al.

3. The process of claim 1, wherein in the framework structure of the zeolitic material provided in (i), the molar ratio Y:X, calculated as YO.sub.2:X.sub.2O.sub.3, is in the range of from 3:1 to 20:1.

4. The process of claim 1, wherein Y is Si and the source of the tetravalent element Y according to (ii) comprises one or more selected from the group consisting of a wet-process silica, a dry-process silica, and a colloidal silica; wherein the AEI framework structure directing agent comprises one or more quaternary phosphonium cation containing compounds and/or one or more quaternary ammonium cation containing compounds; wherein the one or more phosphonium cation containing compounds comprise one or more R.sup.1R.sup.2R.sup.3R.sup.4P.sup.+-containing compounds, wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 independently from one another stand for optionally substituted and/or optionally branched (C.sub.1-C.sub.6)alkyl; wherein the one or more quaternary ammonium cation containing compounds comprise one or more N,N-dialkyl-dialkylpiperidinium cation containing compounds; and wherein the one or more quaternary phosphonium cation containing compounds and/or one or quaternary ammonium cation containing compounds are salts.

5. The process of claim 1, wherein the synthesis mixture prepared in (ii) which is subjected to (iii), the weight ratio of the zeolitic material relative to the source of the tetravalent element Y, calculated as YO.sub.2, is in the range of from 1.0:1 to 3.0:1; wherein the weight ratio of the zeolitic material relative to the water is in the range of from 0.005:1 to 0.030:1; and wherein the weight ratio of the zeolitic material relative to the AEI framework structure directing agent is in the range of from 0.1:1 to 0.9:1.

6. The process of claim 1, wherein the synthesis mixture prepared in (ii) which is subjected to (iii) additionally comprises a source of a base.

7. The process of claim 1, wherein the hydrothermal synthesis temperature is in the range of from 110 to 175 C.

8. The process of claim 1, further comprising (iv) cooling the mixture obtained from (iii); (v) separating the zeolitic material from the mixture obtained from (iv); and (vi) calcining the zeolitic material obtained from (v).

9. The process of claim 1, further comprising (vii) supporting a metal M on the zeolitic material; wherein the metal M is a transition metal of groups 7 to 12 of the periodic system of elements.

10. The process of claim 9, wherein comprises (vii.1) preparing a mixture comprising the zeolitic material, a source of a metal M, a solvent for the source of the metal M, and optionally an acid, (vii.2) heating the mixture prepared in (vii.1) to a temperature in the range of from 30 to 90 C.; (vii.3) optionally cooling, the mixture obtained from (vii.2); (vii.4) separating the zeolitic material comprising the metal M from the mixture obtained from (2) or (vii.3); (vii.5) optionally drying the zeolitic material comprising the metal M obtained from (vii.4) in a gas atmosphere; and (vii.6) optionally calcining the zeolitic material comprising the metal M obtained from (vii.4) or (vii.5) in a gas atmosphere.

11. The process of claim 9, wherein in (vii), the metal M is supported on the zeolitic material in an amount in the range of from 0.1 to 5 weight-%, calculated as elemental M and based on the total weight of the zeolitic material.

12. A zeolitic material having framework type AEI and having a framework structure which comprises a tetravalent element Y, a trivalent element X, and oxygen, and optionally a metal M, obtained by the process according to claim 1, said zeolitic material having a total amount of acid sites in the range of from 1.0 to 2.0 mmol/g, wherein the total amount of acid sites is defined as the total molar amount of desorbed ammonia per mass of the zeolitic material determined according to the temperature programmed desorption of ammonia; wherein the zeolitic material has an amount of medium acid sites in the range of from 0.1 to 0.8 mmol/g, wherein the amount of medium acid sites is defined as the amount of desorbed ammonia per mass of the zeolitic material determined according to the temperature programmed desorption of ammonia in the temperature range of from 250 to 500 C.

13. A catalyst comprising the zeolitic material according to claim 12.

14. A method of selective catalytic reduction of nitrogen oxides in an exhaust gas stream, comprising contacting the exhaust gas stream with the catalyst of claim 13.

15. The method of claim 13, comprising the conversion of a C1 compound to one or more olefins.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0412] FIG. 1: shows the XRD pattern of the zeolitic material according to Example 1.

[0413] FIG. 2: shows the SEM picture of the zeolitic material according to Example 1.

[0414] FIG. 3: shows the XRD pattern of the zeolitic material according to Example 2.

[0415] FIG. 4: shows the SEM picture of the zeolitic material according to Example 2.

[0416] FIG. 5: shows the SEM picture of the natural CHA material provided in Example 2.

[0417] FIG. 6: shows the XRD pattern of the natural CHA material provided in Example 2.

[0418] FIG. 7: shows the water uptake isotherm of the natural CHA material provided in Example 2.

[0419] FIG. 8: shows the XRD pattern of the composition obtained according to Comparative Example 3.

[0420] FIG. 9: shows the SEM picture of the composition obtained according to Comparative Example 3.

[0421] FIG. 10: shows the SEM picture of the zeolitic material provided according to a) in Comparative Example 2.

[0422] FIG. 11: shows the chemical composition (R.sup.2+R.sup.+Si compositional plot) of naturally occurring zeolitic materials, as shown in http://www.iza-online.org/natural/Datasheets/Chabazite/chabazite.htm in section Chemical composition, status 12 May 2017.

[0423] FIG. 12: shows the chemical composition (Na-Cas-K plot) of naturally occurring zeolitic materials, as shown in http://www.iza-online.org/natural/Datasheets/Chabazite/chabazite.htm in section Chemical composition, status 12 May 2017.

CITED LITERATURE

[0424] WO 2013/068976 A [0425] Madsen, I. C., Scarlett, N. V. Y. (2008) Quantitative phase analysis in: Dinnebier, R. E., Billinge S. J. L. (eds) Powder diffraction: theory and practice, The Royal Society of Chemistry, Cambridge, pp. 298-331 [0426] WO 2013/182974 A