The kinetics of silylation of hydroxylated silica 1: Aerosil

Abstract

The kinetics of the silylation of hydroxylated silica, the non-porous Aerosil using trimethylchlorosilane, under various reaction conditions has been investigated by a gravimetric technique and found to follow the law:

$$\left[ {\frac{{1 + b}}{t}} \right]\ln \left\{ {\frac{{M_\infty }}{{M_\infty - M_t }}} \right\} - \frac{{M_t b}}{{M_\infty t}} = k_{\text{a}} $$

which represents a first order reaction retarded by one of its products. From this analysis, the activation energy in the temperature range 598 K to 673 K, was found to be 155 kJ mol⁻¹. The reaction is independent of pressure at values greater than 15 torr.