ChemistryAspirin (Acetylsalicylic acid)

Aspirin (Acetylsalicylic acid)

What is Acetylsalicylic acid?

Acetylsalicylic acid, also known as Aspirin or 2-Acetoxybenzoic acid, is the most common pain reliever. Its chemical formula is C9H8O4. It appears as a crystalline, colourless white powder. Normally odourless, when exposed to damp air it acquires an acetic acid odour. It has a flashpoint of 482 degrees Fahrenheit. It is most commonly employed in the treatment of pain, inflammation, and fever.

On the WHO‘s List of Essential Medicines, aspirin is listed as one of the safest and most effective medicines, as well as one of the most widely used medications in the world.

About Acetylsalicylic Acid – C9H8O4

Acetylsalicylic acid (ASA) is a powerful, irreversible platelet aggregation inhibitor, but it loses its activity upon first-pass deacetylation to salicylic acid ( SA). Acetylsalicylic acid was introduced to the pharmaceutical sector more than a century ago. Although it was initially intended as an analgesic, doctors quickly discovered that it has numerous additional medical applications.

In 1894, the German chemist Felix Hoffman joined Bayer Pharmaceutical Company. In search of medication to alleviate his father’s arthritis pain, he revisited Brugnatelli and Fontana’s salicin, which had been transformed by chemists into pure salicylic acid.

By combining salicylic acid with a buffer to make acetylsalicylic acid (ASA), Hoffman created a molecule with improved tolerability and fewer gastrointestinal adverse effects. In 1899, acetylsalicylic acid was introduced to the market and marketed under the name “aspirin.”

Structure of Aspirin/Acetylsalicylic acid – C9H8O4

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Properties of Aspirin/Acetylsalicylic acid – C9H8O4

C9H8O4Acetylsalicylic acid
Molecular Weight/ Molar Mass180.159 g/mol
Density1.40 g/cm³
Boiling Point140°C
Melting Point136°C

Acetylsalicylic Molecular Formula


Acetylsalicylic IUPAC Name

IUPAC Name for Acetylsalicylic is 2-acetyloxybenzoic acid

Synthesis of Aspirin/Acetylsalicylic acid – C9H8O4

  • Step 1: Add 3 grammes of salicylic acid to a dehydrated Erlenmeyer flask.
  • Step 2: Add 5 to 8 drops of phosphoric acid with a concentration of 85% and 6 mL of acetic anhydride to the flask.
  • Step 3: Mix the solution and soak the flask for 15 minutes in warm water.
  • Step 4: Drop by drop, incorporate 20 drops of cold water into the warm solution. (this eliminates the surplus acetic anhydride)
  • Step 5: Place the flask in an ice bath to chill the contents and expedite the crystallisation process.
  • Step 6: Pour the mixture through a Buckner funnel when the crystallisation process is done.
  • Step 7: Wash the crystals with ice-cold water to get the most out of them.
  • Step 8: Do recrystallization to clean up the product. Place the crystals in 10 millilitres of ethanol. To dissolve the crystals, stir the mixture.
  • Step 9: Pour 25ml of warm alcohol into the solution and cover it so that crystals can form as the solution cools. Once the process of recrystallization has begun, place the beaker in an ice bath.
  • Step 10: Pour out the contents of the beaker and use suction filtration.
  • Step 11 involves removing excess water from the crystals by placing them on dry paper.
  • Step 12: Confirm a melting point of 135°C for acetylsalicylic acid.
Synthesis of Aspirin/Acetylsalicylic acid

Acetylsalicylic Chemical properties

Aspirin rapidly decomposes in solutions of ammonium acetate or alkali metal acetates, carbonates, citrates, or hydroxides. It is stable in dry air but hydrolyzes into acetic and salicylic acids when exposed to moisture. Rapid hydrolysis occurs in the presence of alkalis, and the resulting clear solutions may consist entirely of acetate and salicylate.

Acetylsalicylic Physical properties

Aspirin is a white, crystalline, mildly acidic, acetyl derivative of salicylic acid with a melting point of 136 °C (277 °F) and a boiling temperature of 140 °C (284 °F). At 25 °C (77 °F), its acid dissociation constant (pKa) is 3.5.

Uses of Aspirin/Acetylsalicylic acid- C9H8O4

Acetylsalicylic acid prevents the enzyme cyclooxygenase.

  • It is used to prevent both arterial and venous thrombosis.
  • It is used to treat a variety of headaches kinds.
  • It is used as an anti-inflammatory medication for both acute and chronic inflammation.
  • It is believed to reduce the chance of developing and dying from cancer.
  • Aspirin is an essential component of the treatment for heart attack patients.
  • It is the first-line treatment for acute rheumatic fever symptoms of fever and joint discomfort.

Health Risks Associated with Acetylsalicylic Acid

  • Exposure routes – Contact with the skin or eyes, ingestion, and inhalation.
  • Symptoms include irritation of the eyes, upper respiratory system, and skin, as well as increased blood clotting time, nausea, and vomiting.
  • Aspirin, also known as acetylsalicylic acid (ASA), is commonly used to treat moderate aches and pains and reduce fever. In addition to being an anti-inflammatory medicine, it can also be used as a blood thinner.
  • Aspirin is normally not suggested for children under the age of 16, as it can increase the risk of Reye’s syndrome, which can develop in response to infections such as a cough, influenza, or chickenpox. It could cause lifelong brain damage or death.

Frequently Asked Questions – FAQs

Q.1 What is acetylsalicylic acid used for?

Acetylsalicylic acid (ASA) is used to treat pain, nausea, and swelling associated with several conditions, including lower back and neck pain, measles, chronic colds, burns, menstrual pain, depression, migraines, osteoarthritis, rheumatoid arthritis, sprains and strains, joint damage, toothache, shoulder pain, and bursitis.

Q.2 How does acetylsalicylic acid work?

In addition to inhibiting the body’s pain receptors chemically, aspirin can lessen the risk of heart attacks and strokes. Aspirin prevents blood platelets from constricting and clotting your arteries, so minimising these risks and increasing blood flow to the heart and brain.

Q.3 What are the benefits of aspirin?

Aspirin or acetylsalicylic acid (ASA) is extensively used as a pain reliever and fever reducer for mild aches and discomfort. This anti-inflammatory medication can also be used as a blood thinner. People with a high risk of blood clots, stroke, and heart disease can take modest doses of aspirin for an extended period of time.

Q.4 What is the chemical name for aspirin?

The chemical name for aspirin is 2-Acetoxybenzoic acid. Aspirin, also known as acetylsalicylic acid (ASA), is a commonly used anti-inflammatory and antipyretic medication. Formula and structure: acetylsalicylic acid has the chemical formula C9H8O4 and the extended formula CH3COOC6H2COOH.

Q.5 Who Cannot take aspirin?

Most individuals over the age of 16 can safely use aspirin. However, aspirin is not appropriate for all persons. Never administer aspirin to a youngster younger than 16 years old without a doctor’s recommendation. There may be a relationship between aspirin and Reye Syndrome in newborns.

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