Learn how to prepare Benzotriazole from o-phenylenediamine? It is a heterocyclic compound with the chemical formula C6H5N3.
| Chemical Formula | C6H5N3 |
| Molecular Weight | 119.12 g/mol |
| Chemical Structure | See previous response |
| Melting Point | 97-100 °C |
| Boiling Point | Approximately 360 °C |
| Density | 1.36 g/cm³ |
| Solubility in Water | Slightly soluble |
| Solubility in Organic Solvents | Soluble in many organic solvents |
| Appearance | White to off-white solid |
| Odor | Odorless |
| pH (in solution) | Neutral |
| Flash Point | Not applicable |
| Vapor Pressure | Negligible at room temperature |
| Refractive Index | ~ 1.61 |
| Octanol/Water Partition Coefficient (log P) | Approximately 1.32 |
Benzotriazole derivatives have chemical and biological properties that are versatile in the Pharmaceutical industry like Vorozole (a competitive inhibitor of the aromatase enzyme) and Alizapride (a dopamine antagonist with prokinetic and antiemetic activities).
Preparation of Benzotriazole from o-phenylenediamine
Benzotriazole can be prepared from o-phenylenediamine through a series of chemical reactions. Here is a general outline of the synthesis:
Requirements
- O-Phenylenediamine
- Sodium nitrite
- Glacial acetic acid
- Sodium hydroxide
- Round bottom flask
- Water bath
- Reflux condenser and magnetic stirrer.
Theory
Benzotriazole is synthesized by the reaction of o-phenylenediamine, sodium nitrite and acetic acid. The conversion proceeds by the diazotization of one of the amine group.
Procedure to prepare Benzotriazole from o-phenylenediamine
- Dissolve 10.8 g (0.1 mol) o-phenylenediamine in a mixture of 12 g (11.5 ml, 0.2 mol) of glacial acetic acid and 30 ml of water contained in a 250 ml beaker.
- Warm the mixture slightly.
- Cool the clear solution to 15°C, stir magnetically.
- Add a solution of 7.5 g (0.1-1 mol) of sodium nitrite in 15 ml of water in one portion.
- The reaction mixture becomes warm and within 2-3 minutes reaches a temperature of about 85°C .
- Then begins to cool while the color changes from deep red to pale brown.
- Stir continuously for 15 minutes by which temperature will have dropped to 35-40°C.
- Then thoroughly chill in an ice-water bath for 30 minutes.
- Collect by vacuum filtration and wash with three 30 ml portions of ice-cold water.
- Dissolve the solid in about 130 ml of boiling water.
- Add decolorizing charcoal, filter.
- Allow the filtrate to cool to about 50°C before adding a few crystals of the crude benzotriazole.
- Allow the mixture to attain room temperature slowly (to avoid separation of the material as oil).
- Then thoroughly chill in ice and collect the benzotriazole which separates as pale straw-colored needles, M.P. 99-100°C.
- A second crop may be obtained by concentrating the filtrate.
- The yield is about 8 g (67%).
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