A discussion on the so-called kinetic compensation effect, which has been observed in several heterogeneous catalytic processes and in particular in the direct synthesis of dimethyldichlorosilane, is presented. A possible explanation about the origin of the phenomena in relation to the anisotropic character of the reaction is proposed. A complementary explanation about the mechanism of promoters' action on the direct synthesis reaction is also proposed. These findings were obtained by comparison with analogous characteristics of another silicon reaction, namely, the silicon etching by alkaline solutions, for which similar phenomena are observed.