What Is Acetylsalicylic Acid Definition Formula Synthesis Reactions and Uses
Acetylsalicylic Acid, commonly called ASA or aspirin, is a widely used medication known for its pain-relieving, anti-inflammatory, and antipyretic effects. In addition to treating minor aches and fevers, acetylsalicylic acid plays a substantial role in cardiovascular disease prevention due to its antiplatelet activity. This article explores the definition, chemical properties, mechanism of action, uses, side effects, and how it compares to salicylic acid, giving a comprehensive understanding of acetylsalicylic acid and its importance in chemistry and medicine.
Definition and Acetylsalicylic Acid Formula
Acetylsalicylic acid is a synthetic organic compound classified as a nonsteroidal anti-inflammatory drug (NSAID). Its main use is in reducing inflammation and preventing blood clots.
Chemical Structure and Formula
- The acetylsalicylic acid formula is \( C_9H_8O_4 \).
- Its systematic structure includes an acetyl group attached to the oxygen atom of salicylic acid’s phenolic ring.
- Block formula representation:
$$ \text{Acetylsalicylic acid:}\quad C_9H_8O_4 $$
Physical Properties
- Acetylsalicylic acid appears as white, odorless crystalline powder.
- Acetylsalicylic acid molar mass: 180.16 g/mol
- Acetylsalicylic acid melting point: 135°C (275°F)
- Acetylsalicylic acid boiling point: Decomposes before boiling
Mechanism of Action and Uses
Acetylsalicylic acid acts by inhibiting enzymes involved in the production of prostaglandins and thromboxanes, directly affecting inflammation and blood clotting.
Mechanism of Action
- Irreversibly inhibits cyclooxygenase (COX-1 and COX-2) enzymes.
- Prevents conversion of arachidonic acid to prostaglandin H2.
- Reduces formation of thromboxane A2, decreasing platelet aggregation.
- Result: Anti-inflammatory, analgesic, antipyretic, and antiplatelet effects.
Medical Applications
- Relief of mild-to-moderate pain and inflammation
- Lowering fever (antipyretic)
- Preventing cardiovascular events (anti-thrombotic)
- Management of ischemic stroke and myocardial infarction
- Sometimes administered to dogs under veterinary guidance. Learn how veterinary diagnostics intersect with chemistry.
Comparison: Acetylsalicylic Acid vs Salicylic Acid
- Salicylic acid: Precursor in synthesis, primarily used for topical skin treatments.
- Acetylation of salicylic acid forms acetylsalicylic acid, making it less irritating to the stomach and suitable for oral use.
Safety, SDS, and Side Effects
Acetylsalicylic acid SDS (Safety Data Sheet) includes information on handling, hazards, and emergency measures. Awareness of side effects is essential, particularly for prolonged or high-dose use.
Notable Side Effects
- Gastrointestinal irritation or ulcers
- Increased risk of bleeding or bruising
- Allergic reactions, especially in those with asthma
- Rare: kidney damage, metabolic acidosis at toxic doses
Always consult healthcare professionals regarding dosage, especially when considering for pets or for individuals with pre-existing health conditions.
Additional Details
- Acetylsalicylic acid pronunciation: uh-see-tuhl-suh-LISS-ih-lik ASS-id
- To understand how melting and boiling points affect stability, read about melting points in chemistry.
- For molar mass calculations, explore the importance of Avogadro’s number.
In summary, acetylsalicylic acid is a versatile molecule with significant roles in pain management and cardiovascular protection, stemming from its chemical properties and mechanism of inhibiting platelet aggregation. Recognizing its structure, formula, and physical characteristics, such as the acetylsalicylic acid molar mass and melting point, enhances your grasp of how it functions in both medicine and analytical chemistry. Understanding side effects, as detailed in the acetylsalicylic acid SDS, further helps ensure safe use in humans and even in certain veterinary contexts. For anyone interested in chemical reactions and thermodynamic changes, you can further study concepts like phase changes and melting points.
FAQs on Acetylsalicylic Acid Structure Properties and Applications
1. What is acetylsalicylic acid?
Acetylsalicylic acid is an organic ester compound with the molecular formula C9H8O4 commonly known as aspirin. It is derived from salicylic acid and contains both a carboxylic acid (-COOH) group and an ester (-COO-) functional group. In chemistry, it is classified as an aromatic carboxylic acid ester and is widely studied in organic synthesis and pharmaceutical chemistry.
2. What is the chemical formula and molar mass of acetylsalicylic acid?
The chemical formula of acetylsalicylic acid is C9H8O4 and its molar mass is 180.16 g·mol-1. The molar mass is calculated as follows:
- 9 × 12.01 (C) = 108.09 g·mol-1
- 8 × 1.008 (H) = 8.06 g·mol-1
- 4 × 16.00 (O) = 64.00 g·mol-1
3. How is acetylsalicylic acid synthesized in the laboratory?
Acetylsalicylic acid is synthesized by the esterification of salicylic acid with acetic anhydride. The balanced chemical equation is: C7H6O3(s) + (CH3CO)2O(l) → C9H8O4(s) + CH3COOH(l).
- Salicylic acid reacts with acetic anhydride.
- A small amount of acid catalyst (e.g., H2SO4) is added.
- The product formed is acetylsalicylic acid and acetic acid.
4. What functional groups are present in acetylsalicylic acid?
Acetylsalicylic acid contains a carboxylic acid (-COOH) group and an ester (-COO-) functional group attached to an aromatic benzene ring. Specifically:
- The -COOH group gives it acidic properties.
- The ester linkage is formed by acetylation of the phenolic -OH of salicylic acid.
- The benzene ring makes it an aromatic compound.
5. Is acetylsalicylic acid an acid or a base?
Acetylsalicylic acid is a weak organic acid because it contains a carboxylic acid (-COOH) group that can donate a proton (H+). In aqueous solution, it partially ionizes: C9H8O4(aq) ⇌ C9H7O4-(aq) + H+(aq). Its acidic behavior is similar to other aromatic carboxylic acids, though it is not a strong acid.
6. What is the difference between salicylic acid and acetylsalicylic acid?
The main difference is that salicylic acid has a phenolic -OH group, while acetylsalicylic acid has that -OH group converted into an ester.
- Salicylic acid: C7H6O3, contains -COOH and phenolic -OH.
- Acetylsalicylic acid: C9H8O4, contains -COOH and an ester group.
7. What type of reaction forms acetylsalicylic acid?
Acetylsalicylic acid is formed through an acid-catalyzed esterification reaction (acetylation). In this reaction:
- A hydroxyl group (-OH) from salicylic acid reacts with acetic anhydride.
- An ester bond (-COO-) is formed.
- Acetic acid is produced as a by-product.
8. How do you calculate the theoretical yield of acetylsalicylic acid?
The theoretical yield of acetylsalicylic acid is calculated using stoichiometry based on the balanced equation. Steps:
- Write the balanced reaction: C7H6O3 + (CH3CO)2O → C9H8O4 + CH3COOH.
- Convert mass of limiting reagent to moles.
- Use the 1:1 mole ratio to find moles of product.
- Convert moles of C9H8O4 to grams using 180.16 g·mol-1.
9. What happens when acetylsalicylic acid is hydrolyzed?
When acetylsalicylic acid undergoes hydrolysis, it breaks down into salicylic acid and acetic acid. The reaction in aqueous conditions is: C9H8O4(s) + H2O(l) → C7H6O3(s) + CH3COOH(aq). This is an example of ester hydrolysis, which can be acid- or base-catalyzed.
10. Why is acetylsalicylic acid considered an aromatic compound?
Acetylsalicylic acid is considered aromatic because it contains a benzene ring with a conjugated π-electron system. The benzene ring follows Hückel’s rule (4n + 2 π electrons), where n = 1 gives 6 π electrons. This aromatic structure contributes to its stability and typical electrophilic substitution reactions.
