Synthesis of titanium silicalite-1 using ethyl silicate-40: a new silica source for zeolite synthesis

Abstract

Titanium silicalite-1 (TS-1) was synthesized using ethyl silicate-40 (ES-40) as a new silica source for zeolite synthesis. This procedure is advantageous because of the higher rate of crystallization, enhanced incorporation of Ti and the highly pure sub-micron sized crystalline product, which is highly active for phenol and anisole oxidation by aqueous H₂O₂, furthermore, ES-40 is cheaper compared to tetraethyl orthosilicate (TEOS). The product was characterized by XRD, IR, SEM, UV–VIS and XRF spectroscopy and adsorption studies. The nature of the silicate species in the intermediate stages of the synthesis was characterized by studying the ²⁹Si liquid NMR spectra. It was observed that if tetrabutyl orthotitanate (TBOT) was mixed with ES-40 before hydrolysis while preparing the reactive solution precursor, the Q³ type of silicate species were predominantly formed, which resulted in faster crystallization of TS-1.