Crystallization of FER and MFI zeolites by a vapor-phase transport method

Dry aluminosilicate gels were crystallized to MFI and FER by a vapor-phase transport (VPT) method using ethylenediamine (EDA), triethylamine (Et₃N) and water as vapor sources. The roles of water and amines in this crystallization were investigated. While Et₃N and water encouraged crystallization, EDA acted as a structure-directing agent. A dry gel was crystallized to FER when no water was added. The ²⁷Al- and the ²⁹Si-NMR spectra indicated that all Al atoms were incorporated into the zeolitic framework in the early stage of crystallization and that the rest of the Si-rich phase gradually crystallized. Full crystallization of Si and Al atoms in dry gel was possible by selecting optimum synthetic conditions. FER was transformed to MFI with prolonged crystallization. The structure and crystallinity of zeolite significantly depended on the sort of support on which the dry gel was placed.