Synthesis of pure-silica ZSM-48 zeolite under mild hydrothermal condition with conventional amphiphilic cation by tuning the reactant gel composition

Abstract

We synthesized pure-silica ZSM-48 zeolite with cheap and conventional amphiphilic organic cation, dodecyltrimethyl ammonium cation, as structure-directing agent. Although severe hydrothermal conditions are usually required to utilize organics possessing anisotropic charge distribution, by controlling the water content of the reactant gel, the crystallization was completed within 5 days at 160°C. This approach enabled the ZSM-48 zeolite synthesis with lower synthesis temperature, shorter synthesis period, and higher productivity. Smaller size of the obtained crystals reflected the enhanced nucleation from the concentrated reactant gel. These results suggested that the concentrated system has an advantage in the synthesizing zeolite with an amphiphilic organic cation as structure-directing agent. ©2013 The Ceramic Society of Japan. All rights reserved.