AIM: To Synthesize and submit Benzotriazole from o-Phenylene diamine and report its percentage yields.
APPARATUS:
- Beaker
- Conical flask
- Measuring jar
- Water bath
CHEMICAL REQUIRMENTS:
- O-phenylenediamine
- Glacial acetic acid
- Sodium nitrate.
PRINCIPLE:
The sodium nitrate reacts with glacial acetic acid liberates nitrous acid. The o-phenylenediamine reacts with nitrous acid and produce diazonium ion. When the structure and stereochemistry of diazonium ion are stable, intramoleculer nitrogen coupling occurs and form benzotrizole directly.
PROCEDURE:
Dissolve 1.3g of o-phenylenediamine in a mixture of 1.5 ml of glacial acetic acid and 5ml water in a beaker. Stir until the solid dissolves, warm gently if necessary, cool the solution to 15°C. Stir well and add a solution of 2g of sodium nitrite in 2ml water. Reaction mixture become warm within 2-3 minutes and reaches a temperature of about 85°C and then begins to cool. Colour changes from deep red to pale brown. Continue stirring for 15minutes till the temperature fall about 35-40°C. Thoroughly chill in ice bath for 30 minutes. Filter the product and wash with cold water.
USE: Used in bulk drug industry as an important intermediate compound.
It is the basic nucleus present in antihelminetics drugs like mebendazole, thiabendazole etc.
CALCULATION:
108gm of o-phenylenediamine =119gm of Benzotriazole.
1.08gm of o-phenylediamine = (x) gm of Benzotriazole.
X = (119 X 1.08)/108 = 1.19g
Theoretical yield =1.19gm
Practical Yield = -------- gm
% purity =(Practical yield/Theoritical yield) X 100
REPORT:
Benzotriazole was prepared and submitted. The percentage yield was found to be ------
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