An Integrated, Single Pass Analysis Chip for Ionic Liquids

Over the past decade, ionic liquids have been developed as alternative, environment friendly, solvents. The drive towards cleaner industrial processes has led to the emergence of ionic liquids as potentially preferable solvents for a range of reactions, previously considered harmful and have shown promise in, for example, clean synthesis, electrochemistry, and liquid crystals. Unfortunately, with a few exceptions, ionic liquids have yet to prove their full-scale viability. This is due in large part to the fact that almost all of the available research has focussed on the chemistry rather than developing the data necessary to allow good engineering. However, it has been established that the wide diversity of physical properties that are available in ionic liquid solvents, coupled with their low vapour pressures, give them the potential to be the engineering solvent of choice. These factors also allow the possibility of having the solvent property/structure as a design variable that may be systematically changed to allow optimal performance of the entire process. This would enable plants to be designed without being limited by the solvent used. Despite the enormous potential of this designer solvent approach to optimising reactions, only a handful of ionic liquids are commonly used in current investigations. One of the major reasons is the limited amount of physical property data available as a function of chemical composition. This information is time consuming to collect and requires, for the many measurements necessary, extremely expensive, decilitre quantities of ionic liquid whose purity and exact provenance is known. If ionic liquids are be tailored to meet the needs of a specific process, the physical property database needs to be expanded substantially to include both thermal effects and the variation with added secondary solvent (either another ionic liquid, water or an organic material). In particular, the amount of material necessary for a complete physical property analysis needs to be brought down by about two to three orders of magnitude so that the costs of obtaining the data become negligible. The objective of this proposal is to harness high-throughput, lab-on-a-chip techniques working on very small samples to enable the rapid determination of property variation across a very large composition and temperature space.We believe that the simple availability of such data would serve massively to decrease the reservations regarding the use of ionic liquids in industry by the process engineers and chemists.