Electrochemical reduction of thionyl chloride in LiAlCl4-SOCl2 solutions

The electrochemical reduction of thionyl chloride in 0.5, 1.0 and 1.5 M LiAlCl₄-SOCl₂ solutions was studied at glassy carbon microelectrodes using the technique of cyclic voltammetry. It was shown that the reduction of thionyl chloride in these solutions leads to the deposition of sparingly soluble lithium chloride film on the electrode surface and results in their passivation. The peak heights increased linearly with the square root of voltage scan rate and at a fixed scan rate, the peak heights were found to be independent of electrolyte concentration as well as the speed of rotation of the electrode. It was also shown that both sulfur and sulfur dioxide, which are formed as reduction products of thionyl chloride, do not undergo further reduction in these solutions.