Aim: Preparation of p- nitroaniline from acetanilide

Requirements:

  • Acetanilide
  • Glacial acetic acid
  • Sulfuric acid
  • Nitric acid
  • 70% Sulfuric acid

Procedure:

Step 1: p-Nitroacetanilide from acetanilide

Dissolve 5.0 g. of acetanilide in 6.0 mL of glacial acetic acid in 250 mL beaker. Add 10.0 mL of con. H2SO4 in it the solution should be clear then put the beaker in to ice bath maintain the Temperature of mixture between 0-2 °C. Take 2.5 mL of Con. HNO3 and 1.4 mL of con. H2SO4 mix it and cool it in the ice bath. Add this mixture drop-wise in to the beaker and stir well allow it to stand at room temperature for half hour. Pour the reaction mixture in water containing ice. Filter, it wash and dry it recrystallize from rectified spirit m. p. of product is 214 °C.

Step 2: p-Nitroaniline from p-Nitroacetanilide

Heat a mixture of 5.0 g of p-nitroacetanilide and 30 mL of 70% sulphuric acid in a 100 mL round bottomed flask fitted with reflux condenser for 20 minutes until a test sample remains clear upon dilution with 2-3 times its volume of water. The p-nitroaniline is now present in the liquid as the sulphate pour the clear hot solution in to 250 mL cold water and precipitate the p-nitroaniline by adding of 10 % NaOH solution filter of the yellow crystalline ppt. wash with water recrystallize from hot water m. p. = 148 °C.

Results:

Step 1.

  • Theoretical Yield: ______________g.
  • Practical Yield: ________________g.
  • % Yield of the product: _____________%.
  • M.P of p-Nitroacetanilide: ___________°C

Step 2.

  • Theoretical Yield: ______________g.
  • Practical Yield: ________________g.
  • % Yield of the product: _____________%.
  • M.P of p-Nitroaniline: ___________°C

Chemical Reaction:

Mechanism:

 

Calculation:

Step 1.

  • Theoretical Yield

Acetanilide: C8H9NO (135.0 g.) p-Nitroacetanilide: C8H8N2O3 (180.0 g.)

From Chemical Reaction

135.0 g. Acetanilide             =                      180.0 g. p-Nitroacetanilide

∴ 5.0 g. Acetanilide              =                      (?) g p-Nitroacetanilide

                        = \frac{5.0 \times 180.0}{135.0}

                        = 6.6 g.

  • Practical Yield:

Actual weight of the dried product = ________________g.

  • % of Yield =\frac{\text { Practical Yield } \times 100}{\text { Theoretical Yield }}

                             = _______________%

Step 2.

  • Theoretical Yield

p-Nitroacetanilide: C8H8N2O3 (180.0 g.) p-nitroaniline: C6H6N2O2 (138.0 g.)

From Chemical Reaction

180.0 g. p-Nitroacetanilide             =                      138.0 g. p-nitroaniline

∴ 5.0 g. p-Nitroacetanilide              =                      (?) g p-nitroaniline

                        = \frac{5.0 \times 138.0}{180.0}

                        = 3.83 g.

  • Practical Yield:

Actual weight of the dried product = ________________g.

  • % of Yield =\frac{\text { Practical Yield } \times 100}{\text { Theoretical Yield }}

                             = _______________%