Electrochemical Oxidation in Room Temperature Ionic Liquids

University Of South Carolina At Columbia, Columbia SC

Investigators

Abstract

The objective of this project is to demonstrate environmentally-acceptable methods for complete oxidation of chlorinated solvents for environmental remediation. The active oxygenation species will be superoxide ion, which will be generated in an aprotic room temperature ionic liquid using a suitable cathode. In addition to demonstrating complete oxidation of chlorinated pollutants, partial electrochemical oxidation using the same superoxide chemistry will provide a route for synthesis of organic molecules that are functional derivatives of carboxylic acids. The PI will conduct low-temperature oxidation of wastes via electrochemical generation of superoxide ion in novel ionic liquid solvents. Low-temperature oxidation of waste solvents will provide a much-needed alternative to high temperature waste incinerators, whose use is greatly complicated by regulatory requirements and locating suitable sites. Such superoxide chemistry has previously been demonstrated in volatile and environmentally-suspect aprotic solvents such as dimethyl formamide and acetonitrile. However, ionic liquids are non-volatile and non-flammable, and should minimize the problems of secondary solvent waste and separation of products from solvent. Assuming the basic electrochemistry of superoxide is successful, it is further proposed to conduct organic synthesis by electrochemical activation of carbon dioxide (CO2) and oxygen, followed by carboxylation of appropriate substrates. The classes of molecules to be synthesized are carbamides, which are valuable intermediates in the production of consumer products such as pharmaceuticals and agrichemicals. Present commercial processes may require organic solvents, expensive catalysts, or even phosgene in the synthesis of these intermediates. There is thus a strong motivation for better, sustainable approaches to manufacture of these intermediates. This project supports the development of a clean and environmentally friendly technology for both waste remediation and chemical manufacturing, based on superoxide chemistry. The project will involve a graduate student, a post-doctoral student, and undergraduate students through an existing NSF REU program in the Department of Chemical Engineering at the University of South Carolina.