Synthesis of silicalite-1 in bicontinuous microemulsion containing AOT

Abstract

Silicalite-1 has been hydrothermally synthesized in a bicontinuous microemulsion of tetraethylenepentamine-sodium bis(2-ethylhexly) sulfosuccinate (AOT)-water system containing fluoride ions. The presence of AOT (an anionic surfactant) has been found to be essential for the formation of Silicalite-1 in bulk tetraethylene pentamine solvent. The tetrahedral binding sites of silicon atom have been confirmed by²⁹Si magic angle spinning NMR and FT-IR spectra. Thermogravimetric and differential thermal analysis studies on as-synthesized Silicalite-1 and X-ray diffraction pattern for calcined product established their structural stability. The scanning electron micrographs show the twinned and uniform morphology of crystals. The presence of additive (AOT) lengthens the nucleation period and helps to produce a large size crystal of Silicalite-1.