Synthesis of Salicylic Acid from Wintergreen Oil
Objective – Preparation of salicylic acid (organic synthesis) from methyl salicylate utilizing previously used procedure from the nineteenth century. The final product will then be evaluated in comparison to salicylic acid made from benzene. Discussion – In this synthesis, methyl salicylate is the starting material or precursor and salicylic acid is the target product. It is the major constituent of wintergreen oil. The difference in structures between methyl salicylate and salicylic acid is a single functional group. In methyl salicylate the benzene ring is substituted by two functional groups, a hydroxyl group (-OH) and an ester group (-COOCH3). In salicylic acid the ester group is replaced by a carboxylic acid group (-COOH). The process that causes the ester group to be replaced by a carboxylic acid group is an example of ester hydrolysis under strongly basic conditions. The following is a mechanism for the synthesis of salicylic acid:
Procedure* - See Attached
Data and Observations – Filter Paper : 0.74 g
Boat: 2.35 g
Final Weight of Product: ___________g
The experiment was successfully carried out as expected. First the methyl Salicylate was measured and put into a reaction vial along with 6M NaOH and boiling chips. The sample became a cloudy white color. The reaction flask was connected to a reflux heating set-up and allowed to boil for thirty minutes until the cloudy white color dissolved into a clear liquid and then was cooled to RT. The sample was then transferred to a beaker and approximately 9 mL of sulfuric acid was added to the sample to adjust to pH 2. It was then placed in an ice bath to promote crystallization and then vacuum filtered to produce a white solid. Results and Conclusions – Reflux was conducted to expectations of the procedure as described in Operational Organic Chemistry manual. Temperature was maintained to ensure reflux didn’t exceed more than half of...
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