Reactivity of silanol groups on zeolite surfaces

Alkyl group introduction into zeolite surfaces was attempted utilizing the reactivity of surface silanol groups as lattice defects resulting from hydrothermal or acid treatment of zeolites. The reaction was carried out using organosilane and alcohols, and traced by in situ IR measurement as well as by elemental analysis. In situ IR measurement demonstrated high reactivity of terminal silanol groups. A good correlation was noted between the amount of reacted groups and the amount of terminal silanol groups, indicating high reactivity of terminal silanol groups and very low reactivity of silanol groups that form hydroxy nests. Treated zeolite exhibited high hydrophobicity, such that it floats on water.