Electrochemical Regeneration of Tetramethyl Orthosilicate from Hexamethoxydisiloxane

An electrochemical approach for the regeneration of tetramethyl orthosilicate (TMOS) from hexamethoxydisiloxane (HMDS), which contains electrochemically inert SiO bonds, is presented. This transformation relies on the in situ generation of methoxide ions under cathodic conditions as the key reactive species and the efficient capture of the water produced during the reaction using molecular sieves 3A (MS3A). In addition to the key role of methoxide, mechanistic studies revealed that its gradual electrochemical generation, which is balanced by the anodic generation of protons, maintains a neutral to mildly basic reaction environment. This acid–base balance is crucial to suppress undesired hydrolysis and oligomerization of siloxane species. The reaction proceeds at ambient temperature, which allows using MS3A in a single vessel, thus enabling an operationally simple and energy‐efficient process without the need for heating or metal catalysts.