Electrochemical Reduction of Cyclic and Acyclic Sulfates

Abstract

Abstract It was confirmed that cyclic and acyclic sulfates of diols and monoalcohols could be reduced at cathodes in nonaqueous solvents. The reduction products were greatly affected by the molecular structures of the sulfates. The reduction of the cyclic sulfates of 1,2-diols yielded the corresponding alkenes and disulfate dianions of the parent diols in high yields and current efficiencies were based on one-electron reduction. On the other hand, the cyclic sulfates of 1,3- and 1,4-diols were also reduced by one-electron transfer under similar conditions, but the cycloalkanes expected were not formed and the products were cyclic ethers along with acyclic alkane or unsaturated alcohol. The reduction of the cyclic sulfate of hydrated formaldehyde, which is regarded as a 1,1-diol, did not give any identified products except for a small amount of methane. Finally, acyclic dialkyl sulfates were reduced by one-electron transfer to give complicated mixtures consisting of monomeric alkanes and alkenes, dimeric alkanes, ethers, and/or alkyl metals. Based on the results obtained, the mechanism of reduction of sulfates (mainly cyclic sulfates of 1,2-diols) is discussed.