Retraction of Silicone Electrosynthesis

Here, we describe a method of synthesizing silicones at room temperature in a one step, one pot electrochemical reaction. The current energy intensive method to produce silicones involves carbothermic reduction at temperatures exceeding 2000 °C over coal, which consequentially produces environmentally harmful gases, CO and CO2. Even after this, the metallic Si is subjected to follow up chemical reactions described by Eugene Rochow in 1945 to produce the final silicones. The electrochemical synthesis is achieved by bulk cathodic electrolysis of methanol in the presence of raw SiO2 materials (sand or quartz) at Eappl = −2.7 −− 3.0 V vs Fc/Fc+ couple in two organic solvent/electrolyte systems. Electrodes are a nickel wire cloth, a nickel −chromium wire, a graphite plate, or a Pt basket. The major products in order of relative yields were octamethylcyclotetrasiloxane (D4), hexamethylcyclotrisiloxane (D3), and decamethylcyclopentasiloxane (D5). Ranges for relative yields, or the ratio of the D3,D 4,o rD 5 to the total amount of silicones produced, are 17 −28%, 64−80%, and 5 −8%, respectively. We also provide evidence for a possible mechanistic pathway involving the initiation of a methyl radical followed by radical propagation to the final products through the intermediate dimethyldimethoxysilane. To the best of our knowledge, this is the first report of the reduction of silicon-containing raw materials at room temperature to yield silicones.