CHEM 2513 Lecture Notes - Lecture 16: Fume Hood, Acenaphthene, Fluorene
28 Nov 2018
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Document Summary
Recrystallisation is a method to purify solid compounds that use the difference in solubility between the product and impurities. Procedure: perform solubility tests: set up 3 beakers (400 ml with di water and 2x 150 ml with tap water) on hotplates set to 240 degrees and 150 degrees. Set 400 ml and 150 ml on 240 and the last one on 150 degrees. Fill each test tube with a small spatula of compound with 1 ml of solvent. Unknown neutral pick one that does not dissolve at rt but dissolves when hot: perform recrystallisation: place a beaker with recrystallisation solvent on a hot plate and bring to boil with boiling stick. Add enough solvent to just cover the solid and place both beakers back on hotplate. When boils, add more hot solvent until all solid has dissolved. Stir constantly: allow solution to cool undisturbed in fume hood. Fast, sensitive and simple technique used for many purposes.
