Synthesis and characterization of colloidal TBA-silicalite-2

Colloidal TBA-silicalite-2 (MEL type) was hydrothermally synthesized in the reactant system TBAOH-TEOS-H2O. The influences of reactant composition, reaction temperature, and crystallization period on particle size of the zeolite were investigated. The colloidal silicalite-2 was characterized by XRD, SEM, TEM, FT-IR Si-29 MAS NMR, C-13 CP MAS NMR, thermogravimetric analysis and N-2 adsorption. The as-synthesized colloidal zeolite with a particle size of 100 nm is an agglomerate composed of nano-sized crystals of about 20 nm, displaying unique structural characteristics such as high content of silanol defects in the framework, splitting of the double-ring vibration in FT-IR spectrum and an unusual signal for methyl groups of TBA in C-13 CP MAS NMR spectrum. (C) 2002 Elsevier Science Inc. All rights reserved.