How to write the chemical equation for methyl salicylate?
a) ( CH₃COOH + C₇H₆O₃ → C₈H₈O₃ + H₂O )
b) ( C₈H₈O₃ + H₂O → CH₃COOH + C₇H₆O₃ )
c) ( C₇H₆O₃ + C₈H₈O₃ → CH₃COOH + H₂O )
d) ( CH₃COOH + H₂O → C₇H₆O₃ + C₈H₈O₃ )
The Correct Answer and Explanation is:
The correct answer is a) (CH₃COOH + C₇H₆O₃ → C₈H₈O₃ + H₂O).
Explanation:
Methyl salicylate (C₈H₈O₃) is an ester compound commonly known for its presence in products like wintergreen oil. It is synthesized via an esterification reaction between salicylic acid (C₇H₆O₃) and methanol (CH₃OH). In this case, the reaction involves acetic acid (CH₃COOH) instead of methanol, but the principle remains similar. This reaction is a type of esterification reaction, where an acid reacts with an alcohol, producing an ester and water.
Here is a breakdown of the components involved in the correct equation:
- Acetic acid (CH₃COOH): This is a carboxylic acid with a formula of C₂H₄O₂. It contains a functional group (-COOH) that will react with the hydroxyl group (-OH) of salicylic acid.
- Salicylic acid (C₇H₆O₃): This compound contains a phenolic group (-OH) attached to a benzene ring, along with a carboxyl group (-COOH). This is the reactant that will undergo esterification with acetic acid.
- Methyl salicylate (C₈H₈O₃): The product of the esterification reaction. It is formed when the -OH group from salicylic acid combines with the acetyl group (CH₃CO-) from acetic acid, resulting in the formation of an ester bond and the release of water.
- Water (H₂O): The formation of water is a typical byproduct of esterification reactions. This occurs when the hydroxyl group of acetic acid and the hydrogen from the hydroxyl group of salicylic acid combine.
Mechanism:
The esterification reaction occurs in the presence of a catalyst like sulfuric acid (H₂SO₄) or heat to facilitate the process. The acetic acid donates its acetyl group (CH₃CO-) to the salicylic acid, resulting in the formation of methyl salicylate and water.
In this reaction, acetic acid and salicylic acid combine to form methyl salicylate (C₈H₈O₃), which is the ester, along with the byproduct water (H₂O). Therefore, the correct equation is a).