The role of amines in the synthesis of zeolites by water-organic vapor phase transport

Abstract

A number of articles have been published to illustrate the role of amines for the synthesis of zeolites and porosils. Some of the results are contradictory on the role of amines. In this study, the roles of amines are investigated by water-organic vapor-phase transport method. This method is attractive because the dilution effects by mother liquid can be avoided and the composition of the synthesized zeolite is equivalent to that of the parent gel. Thus, the relation between the gel and amine can be explained clearly. In the zeolite synthesis, the templating effect of amine is less plausible, whereas the molecules with higher dipole moment and appropriate dimension such as propylamine have higher effectiveness. The protonated amines cannot work as active cations independently but amines activate the inactive cations (organic and alkali) in the gel by means of reinforcement of the pH level in the gel.