| 摘要 |
This invention relates to an improved method of preparing a zeolite composition in which some or all of the cations have been exchanged for gallium ions. The zeolite has a high silica to alumina ratio and is prepared by crystallization from an aqueous solution containing a mixture of a source of silica, a source of alumina, and at least two other components selected from the group of alkali metal ions, amonia and an organic nitrogen containing base. The improvement lies in washing the crystallized zeolite with acidified and/or deionized water, calcining the washed product at an elevated temperature, contacting the calcined product with an acid, refluxing the acid treated zeolite with a solution of a gallium compound to produce a gallium exchange zeolite and washing the gallium exchanged zeolite with water to render it substantially free from any impregnated gallium or gallium compound. The zeolite composition is useful as a catalyst for hydrocarbon conversion reactions. |
