The key difference between salicylic acid and acetylsalicylic acid is that the salicylic acid molecule has a carboxyl group and a hydroxyl group attached to a benzene ring whereas the acetylsalicylic acid molecule has a carboxyl group and an ester group attached to a benzene ring.
Acetylsalicylic acid is a derivative of salicylic acid. It forms from the esterification of salicylic acid. Likewise, both these compounds have wide applications in medicine. For instance, acetylsalicylic is what we call in common as “Aspirin”.
CONTENTS
1. Overview and Key Difference
2. What is Salicylic Acid
3. What is Acetylsalicylic Acid
4. Side by Side Comparison – Salicylic Acid vs Acetylsalicylic Acid in Tabular Form
5. Summary
What is Salicylic Acid?
Salicylic acid is a medication that we can use for the removal of the outer layer of our skin. The chemical formula of this compound is C7H6O3 , and molar mass of this compound is 138.12 g/mol. ALso, it appears as a white crystalline solid, which is odourless. Moreover, the IUPAC name is 2-Hydroxybenzoic acid.
Figure 01: Chemical structure of Salicylic Acid
Furthermore, the melting point of salicylic acid is 158.6 °C under controlled conditions, and it undergoes sublimation over 76 °C. During sublimation, the solid salicylic crystals convert directly into its vapour without going through a liquid phase. Also, it decomposes at around 200 °C.
Moreover, it has the majority of its uses in the field of medicine. Thus, we can use it to treat warts, dandruff, acne and other skin disorders. Accordingly, in this, we use its ability to remove the outer layer of the skin. Therefore, this compound is a major constituent in many skincare products. For instance, it is a component of many types of shampoos that we use to treat dandruff. Apart from that, manufacturers use this compound as a food additive as well.
What is Acetylsalicylic Acid?
Acetylsalicylic acid is a medication that we use to treat pain, fever and inflammation. The common name of this compound is Aspirin, the medication that we use in our day to day life. The chemical formula of this compound is C9H8O4, and its molar mass is 180.15 g/mol. The melting point is 136 °C, and it decomposes at around 140 °C.
Consequently, this compound undergoes rapid decomposition in solutions of ammonium acetate, carbonates, citrates, hydroxides, alkali metals, etc. Further, it is stable in dry air, but moisture in the air can cause hydrolysis of the compound. We can synthesize aspirin via esterification of salicylic acid. There, we can treat the starting compound with acetic anhydride. Subsequently, the hydroxyl group of salicylic acid molecules converts into an ester group forming acetylsalicylic acid.
Figure 02: Chemical Structure of Acetylsalicylic Acid
There are many important uses of this medication. For example, if we take this medicine shortly after a heart attack, it decreases the risk of death. Also, it is useful to decrease the risk of heart attacks if we take it long-term. However, there is a common adverse effect; upset stomach. Moreover, some other side effects may include stomach ulcers, stomach bleeding, etc.
What is the Difference Between Salicylic Acid and Acetylsalicylic Acid?
Both salicylic acid and acetylsalicylic acid are useful as medications. The key difference between salicylic acid and acetylsalicylic acid is that the salicylic acid molecule has a carboxyl group and a hydroxyl group attached to a benzene ring whereas the acetylsalicylic acid molecule has a carboxyl group and an ester group attached to a benzene ring. Moreover, there are some other differences as well. As another important difference between salicylic acid and acetylsalicylic acid, we can say their applications.That is; we use salicylic acid to treat warts, dandruff, acne and other skin disorders while we use acetylsalicylic acid to treat pain, fever and inflammation.
Summary – Salicylic Acid vs Acetylsalicylic Acid
The major difference between salicylic acid and acetylsalicylic acid lies upon their chemical structures. That is; the key difference between salicylic acid and acetylsalicylic acid is that the salicylic acid molecule has a carboxyl group and a hydroxyl group attached to a benzene ring whereas the acetylsalicylic acid molecule has a carboxyl group and an ester group attached to a benzene ring.
Reference:
1. “Aspirin.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine. Available here
2. “Salicylic Acid.” Wikipedia, Wikimedia Foundation, 11 Sept. 2018. Available here
Image Courtesy:
1.”Salicylic-acid-skeletal”By Benjah-bmm27 and Booyabazooka, edited by Fvasconcellos (Public Domain) via Commons Wikimedia
2.”Aspirin-skeletal”By Benjah-bmm27 (Public Domain) via Commons Wikimedia