COPPER-CONTAINING SMALL-PORE ZEOLITES HAVING A LOW ALKALI METAL CONTENT, METHOD OF MAKING THEREOF, AND THEIR USE AS SCR CATALYSTS

摘要

The present invention discloses crystalline copper-containing small-pore aluminosilicate zeolites having a maximum pore size of eight tetrahedral atoms, containing 2 to 7wt.-% copper, calculated as CuO and based on the total weight of the respective zeolite, and containing alkali metal cations in a total amount of 0.1 to 0.4wt.-%, calculated as pure metals and based on the total weight of the zeolite, and having a BET surface area of from 320 to 750 m²/g. Furthermore, the invention discloses a process for making said zeolites, comprising the preparation of an aqueous reaction mixture comprising a zeolite of the faujasite framework type, Cu-tetraethylenepentamine (Cu-TEPA) and at least one compound M(OH)_x, wherein x is selected from the group consisting of lithium, sodium, potassium, rubidium and cesium, and heating the reaction mixture to form a copper con- taining small-pore zeolite. The zeolites according to the present invention are suitable SCR catalysts.