The Ionic Liquids project involves the design, synthesis and investigation of ionic liquids. Dr. Robert Palgrave at UCL developed this project in collaboration with Sutton Grammar School and Dr. Jess Wade (Imperial College London). Students synthesise ionic liquids in school using a well-established versatile synthesis procedure.
The main Chemistry topic that this project links to is organic chemistry.
An information presentation is available if you click on ‘Why Study?’ in the Ionic Liquids project page.
School labs should contain all the equipment you already need. However, you may need to purchase the chemicals if your school doesn’t have them already. Many schools use Sigma Aldrich but other suppliers are available.
IRIS is currently looking into opportunities to assist state schools with buying equipment and chemicals and hope to progress this further in 2019. In the meantime, here are some suggestions for funding sources:
Query: We seem to have an issue with the anion (potassium tetrafluoroborate). I weighed out the equivalent 0.05 moles, it dissolved in the 40cm3 of distilled water when heated but it seems to precipitate out quite quickly as soon as the solution cools. So I heated it again and added it to the reflux mixture whilst hot but there is still a sludge that is now contaminating both layers and preventing me from separating the organic layer.
Answer: It sounds like either there is unreacted KBF4 present or you still have some methylimadazolium halide - in both cases the solution would be to reflux for longer, try another 30 mins, with a bit of agitation every now and again to mix the layers and hopefully the reaction will complete. If the sludge is still there, try adding some more water - does it dissolve? If it is BF4 it should eventually dissolve with additional water. If it won't dissolve then the BF4 ionic liquids can be quite viscous, the sludge may be the product?
Query: What’s the best way to confirm that the students have made what they intended to make?
Answer: 1H and 13C NMR is the best way to definitively characterise the products. IR is useful too. Mass spectroscopy is interesting to say the least, ionic liquids normally form very large clusters of up to 15 ion pairs - this is fun to challenge the ideas of mass spectroscopy taught at A level. Of course this will require a university visit.
Query: We meet on a Monday evening and have been functionalising the 1-methylimidazole with 1-chlorobutane, 1-iodobutane, 1-bromobutane, 2-bromobutane and 2-methyl-2-bromopropane. The volumes we're gaining are very small and we're having problems with the solubility of the potassium tetrafluoroborate. The method I have says 6.1 g in 40 mL of water, but a quick search suggests its solubility is 0.45 g/100g, whereas sodium tetrafluorborate is 108 g/100 g.
Answer: The synthesis should give 5g product approximately. If you are getting much less than this something might be going wrong somewhere. You need to heat the water to get KPF6 to dissolve well. To be honest it doesn't matter if it isn't dissolved totally when you put it into the reflux, the reaction will still work (in fact it is possible to do the reaction with no water at all and all in one pot, just by placing the methylimidazole, bromoalkane and KPF6 all in a flask and heating under reflux).
Any unreacted KPF6 can be washed out afterwards - the ionic liquid itself will be immiscable with water.
Your local university should be able to assist with NMR to help you characterise your products. If you don’t already have an established relationship with your local university, please contact who can help.
The project lead, Dr Palgrave, is currently developing a Follow On booklet which should be available in early 2019.