| 摘要 |
<p>A zeolite has a free aperture main channel of a size > 2.2 ANGSTROM , a Si/Al molar ratio < 124/1 and zinc in the framework structure. Preferably the Si/Al molar ratio >/= 1/1. It is prepared by reacting together at least a source of silicon, a source of aluminium, a source of zinc, a source of alkali metal ions and a source of hydroxyl ions. Alternatively, it is prepared by reacting a zeolite having a main channel of a size > 2.2 ANGSTROM and a Si/Al molar ratio < 124/1 with a compound capable of removing aluminium or silicon from the framework structure and providing zinc ions for introduction into the framework structure in plane of the aluminiun or silicon.</p> |
