Aim: Preparation of p-chlorotoluene from p-toluidine.

Requirements:

  • Hydrated copper sulphate = 35 g.
  • Pure Sodium chloride = 9.2 g.
  • Sodium bisulphite = 8.4 g.
  • HCl = 60 mL
  • p-toluidine = 5.0 g.
  • HCl = 10 mL
  • Sodium nitrate = 4.0 g.

Procedure:

Prepare the cuprous chloride solution as follow.

  • Dissolve 35 g. of copper sulphate and 9.2 g. of sodium chloride in 125 mL of water and warming may necessary. Add solution of sodium bisulphite in 90 mL of water shake it for 5 minutes cool the mixture room temperature. Add slowly with constant stirring, the sodium bisulphite solution to copper sulphate and sodium chloride solution. White cuprous chloride precipitate generates, allow the precipitate to settle, and decant most of the supernatant solutions. Filter the solid by suction on a Buchner funnel then wash the precipitate. Dissolve the precipitate cuprous chloride in 60 mL of con. HCl.

Dissolve 5.0 g. of p-toluidine in 10.0 mL of con. HCl and 28.0 mL water in a 250 mL flask cool the mixture to 0 °C in an ice-salt bath with vigorous stirring or shaking. Dissolve 4 g. of sodium nitrate in 10 mL of water add this solution slowly in p-toluidine solution shake well during the diazotization and keep the mixture at 0-5 °C.

Pour the cold Diazonium chloride solutions slowly with shaking in to the cold cuprous chloride. Steam distill the mixture until no oilier drops are presents in a distillate. Treat with ether and magnesium sulphate. Take B.P of p-chlorotoluene.

Results:

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

Chemical Reaction:

Mechanism:

Calculation:

  • Theoretical Yield

p-toluidine: C7H9N (107g.) p-chlorotoluene: C17H14O (126.5 g.)

From Chemical Reaction

107 g. p-toluidine                 =                      126.5 g. p-chlorotoluene

∴ 5.00 g. p-toluidine            =                      (?) g p-chlorotoluene

= \frac{5.00\times 126.5}{107.0}  

= 5.91 g.

  • Practical Yield :

Actual weight of the dried product = ________________g.

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

                             = _______________%