ELECTROCHEMICAL STUDIES IN CYCLIC ESTERS

Solubilities and conductivities of inorganic salts in the cyclic esters ethylene carbonate, propylene carbonate, γ-butyrolactone, and γ- valerolactone have been studied. A number of common inorganic salts were found to be highly soluble in all of these solvents. The variation of solubility with the physical properties of the solvents is discussed. Conductivity measurements have shown that a number of salts investigated behaved as strong electrolytes. Certain solutions of highly soluble inorganic salts were found to have high viscosities in these solvents. Such relatively low-melting covalent halides as AlCl₃, NbCl₅, and FeCl₃ were found to be quite soluble. The solubilities and conductivities characterizing these solutions conform to present- day concepts, and are explained in the light of modern solubility theory. Solutions of a variety of salts were electroreduced, providing further data for the characterization of these solvents. This study indicates that, in addition to those metals which may be obtained from aqueous solutions, some of the highly electropositive metals may also be electrodeposited. These solvents arc characterized by high dielectric constants, low vapor pressures, relatively low toxicity, and high chemical stability, and are relatively nonreactive with anodically liberated halogens. Such properties are desirable in an easily handled ionizing mediuun.