Atranes

The hydrolysis of silatranes of the : type (R=alkyl, aryl) in the presence of HCl at 25°C is described by a second-order kinetic equation. The correlation dependence of the log k values on the σ _OR ^* values makes it possible to divide the investigated compounds into two reaction series — 1-alkoxy- and 1-aryloxysilatranes. An investigation of the potentiometric curves and the change in the acid functions of the media during the hydrolysis of the silatranes made it possible to propose a scheme for the mechanism of this reaction. The linear dependence of the v values on [HCl] provides evidence that noncatylic hydrolysis of the silatranes practically does not occur under the investigated conditions. A salt effect is not manifested during the hydrolysis of the silatranes (at KCl concentrations from 0.05 to 0.25 mole/liter). The toxicity of the 1-aryloxysilatranes is basically reduced as their rate of hydrolytic cleavage increases.