O-Phenylenediamine
 |
|||
|
|||
| Names | |||
|---|---|---|---|
|
Preferred IUPAC name
Benzene-1,2-diamine
|
|||
| Other names
o-Phenylene diamine
1,2-Diaminobenzene 1,2-Phenylenediamine |
|||
| Identifiers | |||
|
3D model (Jmol)
|
|||
| ChEBI | |||
| ChemSpider | |||
| ECHA InfoCard | 100.002.210 | ||
| UNII | |||
|
|||
|
|||
| Properties | |||
| C6H8N2 | |||
| Molar mass | 108.14 g·mol−1 | ||
| Density | 1.031 g/cm3 | ||
| Melting point | 102 to 104 °C (216 to 219 °F; 375 to 377 K) | ||
| Boiling point | 252 °C (486 °F; 525 K) Other sources: 256 to 258 °C (493 to 496 °F; 529 to 531 K) | ||
| soluble in hot water | |||
| Acidity (pKa) | 0.80 pka2 = 4.57 |
||
| -71.98·10−6 cm3/mol | |||
| Hazards | |||
| Safety data sheet | Oxford MSDS | ||
|
EU classification (DSD)
|
Toxic (T); Dangerous for the environment (N) | ||
| NFPA 704 | |||
|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|
|||
 (what is   ?) |
|||
| Infobox references | |||
pka2 = 4.57
o-Phenylenediamine is an organic compound with the formula C6H4(NH2)2. This aromatic diamine is an important precursor to many heterocyclic compounds. It is isomeric with m-phenylenediamine and p-phenylenediamine, and is commonly referred to as OPD.
Commonly, 2-nitrochlorobenzene is treated with ammonia and the resulting 2-aminonitrobenzene is then hydrogenated:
In the laboratory, the reduction of the nitroaniline is effected with zinc powder in ethanol, followed by purification of the diamine as the hydrochloride salt. This compound darkens in air; impurities may be removed by treating a hot aqueous solution with sodium dithionite (reducing agent) and activated carbon, and allowing the product to cool crystallize.
o-Phenylenediamine condenses with ketones and aldehydes to give rise to a variety of useful products. Reactions with carboxylic acids and their derivatives afford benzimidazoles. The herbicide benomyl is prepared in this manner. Also, quinoxalinedione may be prepared by condensation of o-phenylenediamine with dimethyl oxalate. Condensation with xanthate esters affords mercaptoimidazoles, which are used as antioxidants in rubber products. Treatment with nitrous acid give benzotriazole, a corrosion inhibitor. Condensation of substituted o-phenylenediamine with various diketones is used in the preparation of a variety of pharmaceuticals.
...
Wikipedia