Methyl Salicylate has been used for a long time for its pleasant odour and flavour. The objective of this experiment was to carry an organic synthesis; the preparation of salicylic acid from methyl salicylate. To do an organic synthesis, it is needed to chemically modify the molecules of another compound to end up with the desire compound. Methyl salicylate is the major constituent of wintergreen oil, which is why it was used in this experiment as the starting material. The new technique used in this experiment is heating under reflux. Many organic compounds, when heated become volatile and it is easy to lost some. The idea of this technique is to add a vertical condenser to the mixture flask. This will stop the water escaping as it touches the cold surface of the condenser. The condenser has a permanent water flow going in and out and this is why the water drip back to the flask as it touches the cold surface. Vacuum filtration was used isolate the solid from the liquid-solid mixture after the sulphuric acid is qqadded and that the precipitation has occurred and that the pH is down to 2. Recrystallization was then used to purify the salicylic acid formed earlier. Boiling water was used to perform the recrystallization. Melting point helped to characterize organic compound and to assure its purity. Physical Properties
Name Molar Weight Melting Point Boiling Point Density
Methyl salicylate 152.1 g/mol -8°C 223°C 1.174 g/ml
Salicylic acid 138.1 g/mol 159°C - Experimental Data
Started heating under reflux – the heating mantle was set up at 100°C Temperature is 26°C at the beginning. Started Boiling after 10 mins
Stopped heating 45 mins after the first bubbles appeared. The mixture was still blurry but there were no solid compound (except for the boiling chips) Added NaOH More we added NaOH (down to pH 2), a precipitate was formed. Let it cool down for 10 mins in a ice bath. Vacuum Filtration During this vacuum filtration, the...
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