Experiment #: 7
Title: Nitration of Methyl Benzoate – Electrophilic Aromatic Substitution (EAS) Reaction
Purpose:
to synthesize meta-nitro methyl benzoate through an electrophilic aromatic substitution reaction
and confirm the product’s identity and purity using melting point and ¹H NMR spectroscopy.
Procedure:
1. Preparation of Reaction Mixture:
a. Weigh out 6.19 g of methyl benzoate and place it into a 100 mL beaker.
b. Place beaker in an ice bath and allow it to cool to below 5°C.
c. Slowly add 12 mL of concentrated sulfuric acid (H₂SO₄) to methyl benzoate
in small portions, stirring constantly.
d. This step is exothermic, so temperature control is essential.
2. Preparation of Nitration Mixture:
a. In a separate container placed in an ice bath, mix 4 mL of concentrated nitric
acid (HNO₃) and 4 mL of concentrated sulfuric acid.
b. Stir gently and maintain a cold temperature.
3. Nitration Reaction:
a. With methyl benzoate solution still cold (on ice), slowly add nitration mixture
dropwise over several minutes while stirring.
b. Monitor and keep temperature below 10°C.
c. After complete addition, allow mixture to stir for 15 minutes at room
temperature.
4. Quenching Reaction:
a. Pour reaction mixture onto 50 g of crushed ice in a 250 mL beaker.
i. A solid precipitate will form immediately.
5. Isolation of Product:
a. Use vacuum filtration (Büchner funnel with filter paper) to collect precipitated
product.
b. Wash solid with cold water and allow it to dry.
6. Characterization:
a. Measure mass of dry product.
b. Determine melting point range.
c. Analyze product using ¹H NMR spectroscopy.
Data/Results/Calculations:
• Starting Material: Methyl benzoate = 6.19 g
• Theoretical Yield: 8.23g
• Actual (Experimental) Yield: 5.65 g
• Percent Yield Calculation:
o (8.23/5.65)×100 = 68.7% (Fair)
• Melting Point (Experimental):
o Onset = 77.2°C
o Clear = 78.5°C
o Range = 1.3°C
Title: Nitration of Methyl Benzoate – Electrophilic Aromatic Substitution (EAS) Reaction
Purpose:
to synthesize meta-nitro methyl benzoate through an electrophilic aromatic substitution reaction
and confirm the product’s identity and purity using melting point and ¹H NMR spectroscopy.
Procedure:
1. Preparation of Reaction Mixture:
a. Weigh out 6.19 g of methyl benzoate and place it into a 100 mL beaker.
b. Place beaker in an ice bath and allow it to cool to below 5°C.
c. Slowly add 12 mL of concentrated sulfuric acid (H₂SO₄) to methyl benzoate
in small portions, stirring constantly.
d. This step is exothermic, so temperature control is essential.
2. Preparation of Nitration Mixture:
a. In a separate container placed in an ice bath, mix 4 mL of concentrated nitric
acid (HNO₃) and 4 mL of concentrated sulfuric acid.
b. Stir gently and maintain a cold temperature.
3. Nitration Reaction:
a. With methyl benzoate solution still cold (on ice), slowly add nitration mixture
dropwise over several minutes while stirring.
b. Monitor and keep temperature below 10°C.
c. After complete addition, allow mixture to stir for 15 minutes at room
temperature.
4. Quenching Reaction:
a. Pour reaction mixture onto 50 g of crushed ice in a 250 mL beaker.
i. A solid precipitate will form immediately.
5. Isolation of Product:
a. Use vacuum filtration (Büchner funnel with filter paper) to collect precipitated
product.
b. Wash solid with cold water and allow it to dry.
6. Characterization:
a. Measure mass of dry product.
b. Determine melting point range.
c. Analyze product using ¹H NMR spectroscopy.
Data/Results/Calculations:
• Starting Material: Methyl benzoate = 6.19 g
• Theoretical Yield: 8.23g
• Actual (Experimental) Yield: 5.65 g
• Percent Yield Calculation:
o (8.23/5.65)×100 = 68.7% (Fair)
• Melting Point (Experimental):
o Onset = 77.2°C
o Clear = 78.5°C
o Range = 1.3°C
