Challenges and Future Directions

Frank Endres, Andrew P. Abbott, and Douglas MacFarlane 

Electrodeposition from Ionic Liquids. Edited by F. Endres, D. MacFarlane, A. Abbott Copyright 2008 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 978-3-527-31565-9 

Metal ion and halide impurities are an issue in ionic liquids with discrete anions. As we have demonstrated in Chapter 11.5 Li+ (and K+) are common cationic impurities, especially in the bis(trifluoromethylsulfonyl)amides which typically contain 100 ppm of these ions from the metathesis reaction. Although Li and K are only electrodeposited in the bulk phase at electrode potentials close to the decomposition potential of the pyrrolidinium ions, there is evidence for the underpotential deposition of Li and K on gold and on other rather noble metals. For a technical process to deposit nickel or cobalt from ionic liquids the codeposition of Li and/or K, even in the underpotential deposition regime, has to be expected. 

Halide impurities can alter the complex chemistry in ionic liquids and can lead to unexpected oxidation reactions at the counter electrode. Furthermore even low amounts of e.g. chlorine can be formed, leading to some side reactions. 

When ILs were first commercially available, the quality of most samples was questionable as they contained numerous organic and inorganic impurities. More recently different quality levels have been introduced (for synthesis, high purity, ultrapurity). Ultrapure ionic liquids usually contain water, halide and metal ion impurities below 10 ppm and they are currently the best choice for fundamental physicochemical studies. 

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Yussef NN, De Lorenzo C (2006) Pediatric gastrointestinal motility-future directions and challenges. Drug Dis 24 308-312... 

Future Directions and Challenges in Green Chemistry Education... 

ABSTRACT. This paper is a survey of recent progress in the preparation, characterisation, and catalytic properties of metals derived from molecular metal clusters. Particular emphasis is placed on the problem areas, the limitations and shortcomings of the investigations to date, and the types of systems which have not been investigated. Possible future directions and challenges facing research in the general field of cluster chemistry are also discussed. 

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