ALCOHOLIC SOLVENT EFFECT ON SILICA SYNTHESIS - NMR AND DLS INVESTIGATION

The solvent effect on the synthesis of silica particles has been eluci dated through the examination of hydrolysis rate and particle growth b y Si-29 NMR and Dynamic Light Scattering studies, respectively, in var ious alcoholic solvents. Kinetic data obtained from the NMR experiment s indicate that the rate of hydrolysis is fastest in 1-butanol and the rates follow an unusual order of 1-butanol > methanol > ethanol > 2-p ropanol > 1-propanol. This order of the rates of hydrolysis is rationa lized with two opposing factors, steric hindrance reducing the rate an d decrease of hydrogen bonding enhancing the rate. The final particle size increases as the alcohol molecular weight increases. This might b e due to decrease in polarity of the alcohols.