Copper-containing zeolites and their preparation

• US 5,110,777 A
• Filed: 06/14/1990
• Issued: 05/05/1992
• Est. Priority Date: 10/07/1987
• Status: Expired due to Term

• Current Assignee: Tosoh Corporation
• Original Assignee: Tosoh Corporation
• Inventors: Igawa, Kazushige, Kamiyama, Katsumi
• Primary Examiner(s): DEES, CARL
• Application Number:
  US07/537,824
• Time in Patent Office: 691 Days
• Field of Search: 502/71, 502/77, 502/68, 502/86, 502/75
• US Class Current: 502/68
• CPC Class Codes: B01D 2251/2062 Ammonia
• CPC Class Codes: B01D 2255/20761 Copper
• CPC Class Codes: B01D 2255/50 Zeolites
• CPC Class Codes: B01D 2255/911 NH3-storage component incorporated in the catalyst
• CPC Class Codes: B01D 53/9418 for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas
• CPC Class Codes: B01J 29/76 Iron group metals or copper

Abstract

The present invention relates to the production of catalysts and adsorbents which can be used for the removal of nitrogen oxides from exhaust gases containing the same.

Claims

1. A copper-containing zeolite, produced by a process which consisting essentially of:

subjecting a zeolite having lattice spacings (d values) as indicated in the following Table as determined by powder X-ray diffraction to ion exchange with copper ions in an aqueous solution containing a water-soluble copper salt and ammonia;

space="preserve" listing-type="tabular">______________________________________ Lattice Lattice spacing Relative spacing Relative (d value) strength (d value) strength ______________________________________ 11.1 ±

0.3 strong 4.60 ±

0.08 weak 10.0 ±

0.3 strong 4.25 ±

0.08 weak 7.4 ±

0.2 weak 3.85 ±

0.07 very strong 7.1 ±

0.2 weak 3.71 ±

0.05 strong 6.3 ±

0.2 weak 3.04 ±

0.03 weak 6.04 ±

0.2 weak 2.99 ±

0.02 weak 5.56 ±

0.1 weak 2.94 ±

0.02 weak 5.01 ±

0.1 weak ______________________________________

2. The copper-containing zeolite according to claim 1, wherein the zeolite subjected to ion exchange with copper ions has a ratio in moles of SiO₂ to Al₂ O₃ of about 15 to 300.

3. The copper-containing zeolite according to claim 1, wherein the water-soluble copper salt is selected from the group consisting of the sulfate, chloride, acetate and nitrate salts of copper.

4. The copper-containing zeolite according to claim 1, wherein said ammonia is added in the form of ammonia water, hydrous ammonia compounds and aqueous solutions containing dissolved ammonia, and in an amount such that the mixture of the zeolite, water-soluble copper compound and ammonia has a pH of about 4 to 12.

5. The copper-containing zeolite according to claim 1, which has a copper content of greater than 0.03%

11. The copper-containing zeolite according to claim 1, which is in the form of a molding which further comprises a clay binder in the amount of 5 to 30 parts of binder per 100 parts of zeolite.

6. A process for producing a copper-containing zeolite, which consisting essentially of:

subjecting a zeolite having lattice spacings (d values) as indicated in the following Table as determined by powder X-ray diffraction to ion exchange with copper ions in an aqueous solution containing a water-soluble copper salt and ammonia;

space="preserve" listing-type="tabular">______________________________________ Lattice Lattice spacing Relative spacing Relative (d value) strength (d value) strength ______________________________________ 11.1 ±

0.3 strong 4.60 ±

0.08 weak 10.0 ±

0.3 strong 4.25 ±

0.08 weak 7.4 ±

0.2 weak 3.85 ±

0.07 very strong 7.1 ±

0.2 weak 3.71 ±

0.05 strong 6.3 ±

0.2 weak 3.04 ±

0.03 weak 6.04 ±

0.2 weak 2.99 ±

0.02 weak 5.56 ±

0.1 weak 2.94 ±

0.02 weak 5.01 ±

0.1 weak ______________________________________

7. The process according to claim 6, wherein the zeolite subjected to ion exchange with copper ions has a ratio in moles of SiO₂ to Al₂ O₃ of about 15 to 300.

8. The process according to claim 6, wherein the water-soluble copper salt is selected from the group consisting of the sulfate, chloride, acetate and nitrate salts of copper.

9. The process according to claim 6, wherein said ammonia is added in the form of ammonia water, hydrous ammonia compounds and aqueous solutions containing dissolved ammonia, and in an amount such that the mixture of the zeolite, water-soluble copper compound and ammonia has a pH of about 4 to 12.

10. The copper-containing zeolite according to claim 6, which has a copper content of greater than 0.03%.