Solvents of the future
ARC Future Fellow Dr Katya Pas from Monash University is using Raijin to pioneer the potentially industry-revolutionising field of ionic liquids.
Current industry processes, such as making paper from cellulose, use toxic organic solvents that break down and evaporate at high temperatures.
“Ionic liquids are considered the solvents of the future,” explains Dr Pas.
“They have beneficial properties such as high conductivity and being liquid at room temperature, but they do not evaporate, and the majority of them are chemically stable at higher temperatures.
“That means when organic solvents will start to decompose, ionic liquids will actually stay intact which is fantastic because it means that you don’t have to constantly replenish your solvent, plus you will not have the toxic products associated with organic solvents.”
Ionic liquids are generated by weakening the interactions in ionic compounds to reduce their melting temperature.
“Basically ionic materials consist entirely of ions; for example table salt consists of only sodium and chloride ions. Because the main attraction is ionic, it means that the strength is so high that these compounds have a high melting temperature.
“The idea behind ionic liquids is to introduce chemical groups that either ‘shield’ or draw charge away from the centre charge and the result is a conductive salt that has a low melting point.”
Ionic liquids are already being used by industry in Europe to dissolve cellulose at just 80°C, leading to a huge reduction in energy costs. The only downside is the cost of production, says Dr Pas.
“Unfortunately ionic liquids are much more expensive than organic solvents,” she says.
She and her group are using Raijin to develop low-cost methods to predict the properties of ionic liquids for screening.
“There are about one trillion possible ionic liquids,” she says.
“You’d have to spend a century in the lab to be able to go through all the possible combinations. That’s just not sensible in terms of energy and we need ionic solutions soon.”
Dr Pas is also collaborating with Singaporean company H2SG Energy to look at developing ionic hydrogels for use as membranes in energy devices such as fuel cells.
“Honestly I do believe that ionic liquids will be the solvents of the future,” says Dr Pas.
“They are so fantastic in terms of reducing energy that there will probably be no alternative but to go for them, as long as we can reduce the cost of their production.”