In my experience, the biggest problem students have with EE’s is picking the right thing to investigate. Students will tell me they want to carry out an EE in chemistry and have no idea what they will investigate. Those that do have ideas quite often have ideas that are too simple or too difficult, never ‘just right’. Because of this, I would strongly encourage you to tell your students to keep their eyes open and look for an EE in chemistry as often; the idea is everywhere. To illustrate this point, here is an example:
Benzyl alcohol, formula C6H5CH2OH, is also known as phenyl methanol and has the structure:
A look at its hazard sheet states “HARMFUL IF SWALLOWED, INHALED OR ABSORBED THROUGH SKIN. CAUSES IRRITATION TO SKIN, EYES AND RESPIRATORY TRACT. AFFECTS CENTRAL NERVOUS SYSTEM. COMBUSTIBLE LIQUID AND VAPOR. “ (Source: http://hazard.com/msds/mf/baker/baker/files/b1885.htm [accessed 27 August 2018])
I’ve just been using some of this substance to strip paint off a wooden mirror (it goes without saying this was not the neat / pure version – I bought it from the local hardware store, concentration unknown!) The paint stripper is painted onto the mirror and left for around an hour. The effect is amazing, the paint bubbles and peels away from the surface leaving the wood underneath.
The effect is so striking, it did cause me to carry out some research and as I was doing so, I thought that this could be the start of an interesting EE. A quick bit of research found out that it could be used as a solvent for paints – which must be how it strips off the paint. The substance has the consistency and look of washing liquid (detergent), so I guess a mixture has been made to allow the alcohol to cover the paint and stop it evaporating. The alcohol is also slightly soluble in water, which will help it to form an aqueous mixture.
So, what types of things could be investigated? Well, as it is an alcohol, it will react with carboxylic acids to form esters. Esters as you know are not soluble in water, so could it be possible to prepare an ester and isolate it? Would it also be possible to determine the amount of ester (and hence the amount of benzyl alcohol) by calculating the amount of acid used to make the ester? Once the amount of benzyl alcohol has been determined, could it be possible to deduce its concentration and determine if a safe level of the alcohol is being used?
This is just an idea but maybe you could use it to illustrate a point to your students who want to carry out EE’s? What do you think? Have you any other real life examples you have used to stimulate a bit of interest for EE’s with your students or have your students come up with any real life examples themselves? Either way, I would love to know so please do share below!