Coal tar is a viscous liquid obtained by the pyrolysis of coal. During fractional distillation, coal tar is heated and distills away its volatile compounds, namely, benzene, toluene, xylene in the temperature range of 350 K to 443 K. These vapours are collected at the upper part of the fractionating column.
|
Name of the fraction |
Temperature Range |
Name of the component |
1. |
Crude light oil |
350-443 K |
Benzene, Toluene, Xylene |
2. |
Middle oil |
443 - 503 K |
Phenol, Nephthalene |
3. |
Heavy oil |
503 - 543 K |
Naphthalene, Cresol |
4. |
Green oil |
543 - 633 K |
Anthrance |
5. |
Pitch oil |
633 K |
Residue |