Isothermal template removal from MCM-41 in hydrogen flow

Thermal evacuation of template surfactant from MCM-41 in hydrogen atmosphere was investigated. Micelle templated silica was prepared using hexadecyltrimethylammonium bromide. The mechanism of template removal appears to be completely different in hydrogen as compared to calcination in air. It seems that moderate heating of as-synthesized MCM-41 (up to about 250 degrees C) in hydrogen stream for about 15 h is effective and simple method of template removal leaving no pure carbon residues on silica surface. Adsorption properties of partially evacuated MCM-41 samples were tested using gas chromatography. Products of template degradation were analyzed using GC-MS technique. The main products of template degradation at 250 degrees C in hydrogen flow are hexadecene and hexadecane-N,N-dimethylamine. Concentration of surface silanols for MCM-41 calcined and thermally treated in hydrogen flow was investigated by NMR technique. (C) 2006 Elsevier Inc. All rights reserved.