Process for the preparation of zeolites having CHA structure

Patent metadata

Field	Value
Publication number	US-9895684-B2
Application number	US-201414534642-A
Country	US
Kind code	B2
Filing date	Nov 6, 2014
Priority date	Nov 24, 2009
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

Zeolites having CHA framework structure and a composition comprising the molar ratio (n SiO2): X203, wherein X is a trivalent element, and wherein n is at least 10, wherein the crystal size, as determined from Scanning Electron Microscopy, is greater than 1 micrometer and wherein the chabazite framework is phase-pure having an impurity of other zeolitic frameworks, such as RUT 25 as determined by X-ray Diffraction, of less than 5%. The process for the preparation comprises:
(i) preparation of an aqueous solution containing at least one source for X203 , wherein X is selected from Al, B, Ga, and a mixture of two or more, and at least one source for SiO2, at least one organic structure directing agent (SDA) other than Tetramethylammonium hydroxide (TMAOH), acting as a template for the CHA structure, and Tetramethylammonium hydroxide (TMAOH), wherein the SDA or mixtures thereof are employed in such amounts that the aqueous solution in (i) exhibits a molar ratio of SDA : TMAOH of 0.01 to 5;
(ii) hydrothermal crystallization of the aqueous solution according to (i); wherein the aqueous solution of (i) contains copper in an amount less than 0.005 Cu:((n YO2)+X203) where n is in the range of 10 to 50.

First claim

The invention claimed is:

1. A zeolitic material having framework structure CHA, having a composition comprising the molar ratio (n SiO 2 ):X 2 O 3 , wherein X is a trivalent element, and wherein X is selected from Al, B, Ga, and a mixture of two or more, and n is at least 10, obtainable by a process comprising:
(i) preparation of an aqueous solution containing:
at least one source for X 2 O 3 , wherein X is selected from Al, B, Ga, and a mixture of two or more,
at least one source for SiO 2 ,
at least one organic structure directing agent (SDA) other than Tetramethylammonium hydroxide (TMAOH) as a template for the CHA structure, and
Tetramethylammonium hydroxide (TMAOH),

wherein the SDA or mixtures thereof are employed in such amounts that the aqueous solution in (i) exhibits a molar ratio of SDA:TMAOH in the range of 0.01 to 5;
(ii) hydrothermal crystallization of the aqueous solution according to (i);
wherein the aqueous solution of (i) contains copper in an amount less than 0.005 Cu: ((n SiO 2 )+X 2 O 3 ) where n is at least 10, and
wherein the zeolitic material having framework structure CHA has a sodium content of 1000 ppm or less.

2. A method for the selective reduction (SCR) of nitrogen oxides NO x , for the oxidation of NH 3 or for the decomposition of N 2 O, the method comprising contacting a stream comprising NOx, NH 3 or N 2 O with a catalyst comprising the zeolitic material of claim 1 .

3. A method for catalyzing a chemical reaction, the method comprising using the zeolitic material of claim 1 as a catalytically active material in a chemical reaction.

4. A catalyst comprising the zeolitic material of claim claim 1 .

5. The zeolitic material of claim 1 , wherein the aqueous solution obtained in (i) and subjected to hydrothermal crystallization in (ii) is free of sodium.

6. The zeolitic material of claim 1 , wherein the aqueous solution obtained in (i) and subjected to hydrothermal crystallization in (ii) has a sodium content of 1000 ppm or less.

7. The zeolitic material of claim 1 , wherein the zeolitic material is free of sodium.

8. A zeolitic material having framework structure CHA, having a composition comprising the molar ratio (n SiO 2 ):X 2 O 3 , wherein X is a trivalent element, and wherein X is selected from Al, B, Ga, and a mixture of two or more, and n is at least 10, and wherein the crystal size of that zeolitic material, as determined from Scanning Electron Microscopy, is greater than 1 micrometer and wherein the chabazite framework is phase-pure having an impurity of other zeolitic frameworks of less than 5%, as determined by X-ray Diffraction, and
wherein the zeolitic material having framework structure CHA has a sodium content of 1000 ppm or less.

9. The zeolitic material of claim 8 , wherein the crystal size is in the range of greater than 1 micron to 5 microns.

10. The zeolitic material of claim 8 , wherein the chabazite framework is phase-pure having an impurity of other zeolitic frameworks of less than 1%.

11. A method for the selective reduction (SCR) of nitrogen oxides NO x , for the oxidation of NH 3 or for the decomposition of N 2 O, the method comprising contacting a stream comprising NOx, NH 3 or N 2 O with a catalyst comprising the zeolitic material of claim 8 .

12. A method for catalyzing a chemical reaction, the method comprising using the zeolitic material of claim 8 as a catalytically active material in a chemical reaction.

13. A catalyst comprising the zeolitic material of claim claim 8 .

14. The zeolitic material of claim 8 , wherein the zeolitic material is free of sodium.

Assignees

• Basf Se

Inventors

• Bull Ivor
• Mueller Ulrich

Classifications

• C01B39/02

  Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof · CPC title

• C01B39/48

  using at least one organic template directing agent · CPC title

• C01P2006/12

  Surface area · CPC title

• C01B39/04 Primary

  using at least one organic template directing agent, e.g. an ionic quaternary ammonium compound or an aminated compound · CPC title

• B01D2255/50

  Zeolites · CPC title