Mechanism of Solid/Liquid Interfacial Reactions. The Hydrolytic Dissolution of Solid Triphenylmethyl Chloride in Aqueous Solution

The reaction between solid triphenylmethyl chloride (TPMCl) and water, TPMCl(s) + H2O(l) → TPMOH(aq) + H+(aq) + Cl-(aq), where TPMOH is triphenylmethyl alcohol, has been investigated using the channel flow cell method. It is found that hydrolysis proceeds via a direct heterogeneous fashion whereby the reaction occurs at the solid−liquid interface rather than in solution after the prior dissolution of TPMCl. Kinetic parameters are reported including the effect of ionic strength. Further, using experiments conducted with different surfaces of single crystals of TPMCl, it is shown that the rate of the interfacial process depends on the availability of exposed chlorine atoms in the reacting crystal plane. In situ atomic force microscopic studies indicate that the TPMCl surface, once in contact with water, is covered rapidly by a porous product layer. However, the latter provides a negligible effect on the reaction rate because of its high porosity.