Microwave synthesis of LTN framework zeolite with no organic structure directing agents

We present a new microwave synthesis method of Linde Type N zeolite without organic structure directing agents (OSDAs). Linde Type N zeolite (framework type LTN) is one of the most complex zeolite structures with a very large unit cell. It has been synthesised previously using hydrothermal methods. We also report syntheses of zeolite A with LTA framework without OSDAs, by hydrothermal methods at low temperatures (40–60 °C). The as-synthesised zeolites were characterised using X-ray powder diffraction, solid state nuclear magnetic resonance, and scanning electron microscopy. LTA and LTN frameworks are obtained at lower synthesis temperatures, while sodalite (SOD framework) is produced at higher temperatures, confirming the crystallization of denser zeolites at higher temperatures.