Electrochemical oxidation of multisulfur heterocycles in molten AlCl3−NaCl mixtures

✍ Scribed by K.W. Fung; J.Q. Chambers; G. Mamantov

• Publisher: Elsevier Science
• Year: 1973
• Weight: 475 KB
• Volume: 47
• Category: Article
• ISSN: 0022-0728
• DOI: 10.1016/s0022-0728(73)80346-8

✦ Synopsis

Molten chloroaluminates have proven to be versatile solvents for a variety of electrochemical studies. The low liquidus temperatures of A1C13-NaC1-KC1 mixtures and the use of aluminum anodes in these melts suggest intriguing applications in the area of non-aqueous batteries and fuel cells 1-3. Metal ion reductions are well documented in the literature on chloroaluminate solvents. This area has been reviewed by two of us a .

Recently, we have examined the anodic electrochemistry of two multisulfur heterocycles in AIC13-NaCI mixtures. The compounds studied were a tetrathioethylene (1) and thianthrene (II).

I 7r

The electrochemistry of these compounds has been studied previously in acetonitrile solutions 5-9. The tetrathioethylene (I) and related compounds are relatively inert chemically and have a particularly simple electrochemistry 5. These compounds do not undergo extensive chemical reactions characteristic of electron-rich olefins, they yield the dication in two reversible one-electron steps in acetonitrile, and may be good cathode sYstems in molten chloroaluminates. Previous studies of organic electrode reactions in these melts are scarce. Fleischmann and Pletcher a o obtained oxidation waves for aromatic hydrocarbons in 50-36-14 mol~ A1C13-NaC1-KCI at 150°C. Complex behavior was observed, although the initial oxidation products of pyrene, anthracene, and diphenylanthracene did exhibit some stability. Recently, Jones et al. 1 ~ examined the oxidation of several aromatic amines in 50--50~o A1C13-NaC1 at 175°C. Firm voltammetric evidence was obtained for the stabilization of the radical cations of triphenylamine, diphenylamine, and N,N-dimethylaniline relative to their behavior in acetonitrile. These authors stated that they were not able to reproduce the results of Fleischmann and Pletcher.