Ionic Liquids Research
The main research interests of the group are firmly based around green chemistry with particular emphasis on electrochemical processes. It is active in developing novel solvent systems with industrial applications such as metal deposition and dissolution. It collaborates strongly with industry and much of the work to date has been in the development of novel processes using ionic liquids. Ionic Liquids Laboratory web page.
Room temperature ionic liquids
We have recently developed a range of ionic compounds, which are fluid at room temperature. These ionic liquids are based on choline chloride (vitamin B4) which is produced on the Mtonne p.a. scale and hence these ionic liquids can be applied to large scale processes for the first time. A joint venture involving the University and Whyte Chemicals Ltd. was started in 1999. This partnership allows fundamental and applied research to be carried out while providing the production, marketing and licensing capability of Britain's largest privately owned chemical company. This joint venture company Scionix Ltd. initially put in place at the University, a research group of 3 post-doctoral fellows who carried out the initial investigations to ensure that the intellectual property was developed and protected. The company now holds four worldwide patents that cover over a million ionic liquids and it has made 200kg batches of ten ionic liquids that it is selling internationally. This makes it one of the world's largest manufacturer of ionic liquids. A number of applications are currently under development.
- Electrodeposition of chromium, zinc and various alloys:
- This is currently in the beta-test scale using 50 litre baths to coat. The work is now the basis for a 4 year, 13M Euro Integrated Project involving 36 companies and universities.
- This project is funded by the DTI and allows a benign ionic liquid to be used in place of phosphoric acid/sulphuric acid mixtures. A 1300 litre test facility has been constructed in Birmingham and extensive tests have shown that significant benefits can be obtained over aqueous acid technology.
- Ore processing:
- A process is under development to extract metals from ore samples using ionic liquids and recover the metals using electrodeposition. A spin-off process to recover Pt and Pd from spent car catalysts is being scaled up to a 1 tonne pilot plant.
- Electroless deposition
- processes have been developed for a number of metals onto a variety of substrates.
We are currently in discussions with a number of large companies about licensing ionic liquid technology for catalytic reactions, electropolishing, pickling and cleaning applications.
In addition to these applied areas we are currently studying the fundamental aspects of solvation in these novel media to elucidate solubility and reaction mechanisms. The relationship between structure, polarity and phase behaviour is also under investigation and we are using hole theory to model physical properties such as viscosity and surface tension. We have recently used this new theory to develop less viscous ionic liquids by fluorination of the hydrogen bond donors.
The group pioneered electrochemical studies in sc. We designed and built the sophisticated equipment necessary for operating at high pressures and temperatures and developed electrochemical sensors to measure solubility and follow rates of reactions in situ. We have characterised solvation in supercritical fluids and the effects of density on solute-solute interactions, most notably with ionic species. We have also just completed the first comprehensive study of hydrogen bonding in supercritical fluids and these data are being used to interpret the pressure dependency of the product distributions for a variety of reactions. Our initial work was funded by the EPSRC, Ineos Fluor and Advanced Phytonic Ltd. We have pioneered the use of supercritical hydrofluorocarbon solvents for catalytic reactions. An EPSRC funded postdoctoral researcher studied the mechanisms of a number of reactions in these media and I currently have two industrially funded students looking at Friedel Crafts and hydrogenation reactions and an EPSRC funded PDRA studying metal catalysed polymerisation in scHFCs. Impact Faraday funded a studentship to investigate the formation of colloids such as emulsions and micelles in sc fluids. This was an unexplored area where we hope to make significant advances as clustering has important ramifications for product separation, reaction mechanism and solute solubility. These colloids were characterised using quartz crystal microbalance, voltammetry, density and conductivity measurements and measure the effect of clustering/local density on the above applications.
We have also been studying the area of gas expanded liquids. The principle behind this technology is that solvent properties can be tuned by pressurising a liquid with a gas. This has important ramifications for phase transfer catalysis and natural product extraction.