碱金属离子X型沸石的固相离子交换及其催化性能的研究

本文考察了水合13X沸石与碱金属盐类间的固相离子交换反应,并对交换样品的比表面、孔容和异丙醇分解反应活性进行了测定。结果表明,这种类型的固相离子交换在室温下即可发生。体积较大的Cs^+比K^+难于交换,高温焙烧有利于有提高Cs^+的交换度。固相交换样品的比表面、孔容变化和异丙醇分解反应活性都与液相交换样品相同,只是交换度的函数,与交换方法无关。与K^+交换样品相比,Cs^+交换样品中Cs^+离子更多地占据超笼,导致更高的超笼局部碱性和脱氢反应活性。

Solid-state ion exchange and catalytic properties of alkali cation exchanged X zeolites

The solid-state ion exchange between hydrated 13X and alkaline metal salt was studied. The surface area, the pore volume and the catalytic performance of the as-exchanged samples were measured and compared with those of the samples obtained by conventional exchange. XRD patterns of the exchanged samples show that the exchange reaction can occur at ambient temperature. Compared with K^+ ion, the bulky Cs^+ ion is more difficult to replace Na^+ ion. The calcination at a higher temperature favours to increase the exchange degree of Cs^+- exchanged sample. The surface area, the pore volume and the activity of isopropanol decomposition reaction are only a function of exchange degree and are not affected by the exchange methods. Cs^+-exchanged samples possess higher local basicities in surpercages and dehydrogenation activities than K^+-exchanged samples with the same δ ~O^- value.