摘要
以NaY沸石为原料,用SiCl_4同晶取代法制备了不同硅铝比且具有高结晶度的八面沸石,进一步将样品交换成铵型。还制备了超稳Y样品及铝交换型八面沸石。研究结果表明,随骨架硅铝比提高,八面沸石的骨架稳定性、热稳定性及水热稳定性均得到很大改善。骨架外铝会使较低硅铝比样品的水热稳定性变差。钠型及铵型样品在不同硅铝比时,对稳定性有不同影响。在骨架硅铝比相近情况下,SiC1_4脱铝沸石(DNH_4Y)较水热法脱铝沸石(USY)有好得多的热稳定性,然而二者却具有相近的水热稳定性。
The stability of a series of faujasites (DNaY, DNH4Y) with different Si/Al ratios, dealuminated by SiCl4 vapor substitution, was systematically studied by IR and DTA methods. As the Si/Al ratio of the sample increased, the skeleton stability, the hydrothermal stability, and the thermal stability could be improved to a great extent. At different Si/Al ratio, the stability of the Na type and NH4 type samples changed in different ways. The presence of extra framework Al caused the decrease of the hydrothermal stability of the sample with low Si/Al ratio. At comparable skeleton Si/Al ratio. the thermal stability of the SiCl4 substituted sample (DNH4Y) was much higher than that of the hydrothermal treated sample (USY) . A conceivable interpretation and discussion had been made on the above results.
基金
国家自然科学基金
