摘要
由碱金属氯化物ＭＣｌ（Ｍ＝Ｌｉ，Ｋ、Ｒｂ，Ｃｓ）和ＮＨ４Ｙ固态离子交换制备ＭＹ分子筛研究表明，离子交换度强裂依赖于Ｍ＋的大小，Ｌｉ＋离子小，交换度几乎达到１００％，而Ｒｂ＋和Ｃｓ＋体积大，不易进入分子筛β笼，但和溶液交换比较，其交换度明显高得多，Ｋ＋有效直径和β笼窗口接近，但ＫＣｌ的晶格能较大，固态交换的优越性不大。
Zeolties MY(M=Li,K,Rb and Cs)were prepared by solid-state ion exchange between NH 4Y and respective chlorides and analyzed by IR and XRD The degree of exchange strongly depends upon the sizes of alkali cations LiY with nearly 100% of the degree of exchange can be obtained via solid-state reaction due to the small size of Li + cations In the cases of the solid-state reactions of RbCl or CsCl with NH 4Y,the degrees of exchange are much higher than those via aqueous exchange,but relatively lower than that of LiY due to the large sizes of Rb + and Cs + which partially prevent the cations from penetrating into the small cages of the zeolites For the preparation of KY,due to the similar size of K + to that of β cages of the zeolite and the large crystalline energy of KCl,the degrees of one-fold solid-state and aqueous exchange are similar.
基金
国家教委优秀青年教师基金
