There is no doubt that the use of ionic liquids in synthesis and catalysis has become very fashionable. They have been reported well beyond the primary chemical literature and have even been featured in The Economist. So far, this has led to an ever-increasing number of publications each year. Part of this fashion comes from the belief that their potential for industrial application is huge. This promise is beginning to be realized in some cases. The other part comes from them being fascinating materials.

I have the good fortune to have been working in the field since well before this excitement began and have, I hope, made some useful contributions to it. I was very lucky to have a review article published just as interest in the ionic liquids exploded. I don’t think that it is any better than many of the reviews that have appeared since, but, because of the timing, it was many people’s academic introduction to the field.

With my own work, I have always tried to balance my work between charging headlong to the next new potential application and trying to gain a deep understanding of the phenomena being observed. This second element is usually more difficult and slower to achieve, but it provides for far more interesting papers in the long run. I also try to venture my own opinions in my publications. I try to sum up what the evidence points towards and to enter into the scientific debate. I don’t claim to be right every time and I am happy to find that new evidence favors a different explanation, but the debate is needed if full understandings are to be reached. Of course citations occur as the debate goes on. Finally, I try to write my papers in a clear and uncomplicated style using straightforward language. I believe that resorting to jargon is a failure in communicating. I hope that my papers are accessible to the reader, regardless of their native language. I think that these approaches come together to make the papers highly read and then highly cited.

The University of Sussex, where I studied, was the kind of place where what we now understand to be the green movement, in the broadest possible sense, was being taken seriously long before it reached the center of the political stage. Even though I was not one of its members, it did have some influence on my thinking. I knew that my understanding of chemistry was not sophisticated enough for me to be able to tell the difference between projects that might be damaging or beneficial, so I chose to work on a project that was useless. The idea was that, if it was of no use to anybody, it might not be beneficial but at least it wouldn’t be damaging. That project was to work on ionic liquids. Oh how things change!

During that project I, like many others have done since, became captivated by these systems. The simple fact of having two things, the cation and the anion, that you can change has the most profound of effects. Although I have dabbled in other areas, I have always worked with ionic liquids and will probably do so for some time.

I think that the main contribution that I have made to the field is that I bring with me an interest in chemical synthesis with an absolute commitment to it being a quantitative science and not just cooking. I try—sometimes successfully, others not—to establish a link between observed reactivities and more fundamental physical properties. This provides insight into how processes occur and then into how they might be improved. I try to find a way for the synthetic chemists to talk to their physical-chemist colleagues.

When I first started working with ionic liquids they were a laboratory curiosity, perhaps with potential applications in battery technology. Now they are used in high tonnage industrial processes. There has been a revolution in this field.

The one thing that I have learned in working with ionic liquids is that any predictions that you make will be proved wrong. Nobody predicted that the first application of ionic liquids in industry would be a large-scale stoichiometric reaction producing a product of moderate cost. Everyone thought that it would be a highly sophisticated catalytic process, probably enantioselective and definitely making a high-cost product.

Enjoy your work, or do something else, and try to do work that is really interesting. It’s easy to find yourself publishing a series of communications without ever producing the full papers. In the end, your colleagues will thank you more and read your work if they think it is going to tell them something that they didn’t already know.

Dr. Tom Welton
Department of Chemistry
Imperial College
London, United Kingdom