Practicals

• Describe the method to produce Oil Of Wintergreen

  1. Add salicylic acid to a round bottom flask and excess methanol then add a few drops of concentrated H2SO4 and mix
  2. Gently heat the mixture under reflux to allow the ester to form without losing volatile compounds
  3. Then cool the mixture by pouring it into cold water to hydrolyse any unreacted acid anhydride and help the ester separate out and the ester (methyl 1,2 - hydrobenzoate) will form an oily layer
  4. Transfer the mixture to a separating funnel and shake and separate the organic layer ( containing the este)
  5. Wash organic layer with Na2CO3 solution to remove any unreacted acid and then wash with water to remove acid/methanol
  6. Then dry organic layer using anhydrous Na2SO4 / MgSO4
  7. Distill the product to purify oil of wintergreen and collect the fraction in the correct boiling point
• Describe the steps of Thin Layer Chromatography

  1. Draw a pencil line on the plate above solvent level
  2. Spot the mixture and pure samples onto pencil line
  3. Place plate in a beaker of solvent and have the beaker covered
  4. Remove plate when solvent front is near to the top of the plate and mark how far the solvent has reached
  5. Allow the plate to dry and locate any spots with iodine/ under a UV lamp