Oxalic acid is an interesting di-carboxylic acid. This is a molecule that is usually associated with kidney stones, however this painful but interesting molecule, although extremely poisonous, is found in many members of plant species. This includes rhubarb! Rhubarb leaves contain about 0.5% oxalic acid!
Going from CH3C00H to (COOH)2:
To me, this looked pretty impossible–>although these are both compounds found in common food products, it is hard to fathom the steps needed to get from one to the other (Ethanoic acid is sometimes known as “vinegar”). However, the more I looked at this, the more I realised that it actually just takes a combination of 3 well known learnt at AS.
CH3COOH –> CH2CLCOOH –> CH2(OH)COOH –>(COOH)2
The first step is just free radical substitution using UV light and chlorine, the second, a nucleophllic substitution using NaOH (aq) and the third just oxidation with potassium dichromate and H2SO4 under reflux!