"Synthesis of Paracetamol by using p-amino phenol"

 

"Synthesis of Paracetamol by using p-amino phenol"

Theory:

Paracetamol, also known as acetaminophen, is a widely used analgesic and antipyretic drug. Its chemical name is N-acetyl-para-aminophenol. Paracetamol can be synthesized through a multi-step reaction starting from phenol.

Chemicals Required:

• 4-Aminophenol
• Acetic anhydride
• Concentrated sulfuric acid
• Distilled water

Apparatus Required:

1. Round-bottom flask
2. Reflux condenser
3. Separatory funnel
4. Filtration setup
5. Vacuum pump
6. Glass stirring rod
7. Beakers
8. Heating mantle
9. pH meter
10. Thermometer

Chemical Equation:

Mechanism:

Procedure:

Acetylation:

a. In a round-bottom flask, combine 20 g of 4-aminophenol with 50 mL of acetic anhydride.

b. Add a few drops of concentrated sulfuric acid to the flask.

c. Reflux the mixture for 3-4 hours at a temperature of 120-130°C.

d. Stir the reaction mixture intermittently during refluxing.

Cooling and Filtration:

a. Allow the reaction mixture to cool to room temperature.

b. Pour the mixture into a beaker containing cold water.

c. Filter the precipitated paracetamol using a Buchner funnel and wash it with water.

Drying and Purification:

a. Dry the paracetamol precipitate by suction filtration using a vacuum pump.

b. Purify the dried paracetamol by recrystallization from a suitable solvent (e.g., ethanol).

Calculations

Calculate the molar mass of 4-aminophenol

Molar mass of 4-aminophenol (C₆H₇NO) = (12.01 g/mol × 6) + (1.01 g/mol × 7) + (14.01 g/mol) + (16.00 g/mol)

Molar mass of 4-aminophenol = 109.13 g/mol

Moles of 4-aminophenol = Mass of 4-aminophenol / Molar mass of 4-aminophenol

Moles of 4-aminophenol = 20 g / 109.13 g/mol ≈ 0.183 mol

Since the acetylation reaction involves a 1:1 stoichiometry between 4-aminophenol and paracetamol, the moles of paracetamol formed will also be 0.183 mol.

Yield Calculation:

Assuming an ideal situation with a 100% yield, the yield of paracetamol would be 0.183 mol.

To calculate the mass of paracetamol

Mass of paracetamol = Moles of paracetamol × Molar mass of paracetamol = 0.183 mol × (12.01 g/mol × 8 + 1.01 g/mol × 9 + 14.01 g/mol + 16.00 g/mol × 2) ≈ 19.36 g

Mass of paracetamol = 19.36 g

Precautions:

• Wear appropriate personal protective equipment (lab coat, gloves, safety goggles) while handling chemicals.
• Perform the synthesis in a well-ventilated fume hood to avoid inhalation of toxic fumes.
• Use caution while handling concentrated sulfuric acid and acetic anhydride, as they are corrosive.
• Follow good laboratory practices and adhere to local safety regulations.
• Dispose of chemical waste properly according to safety guidelines.