Coal tar distillation is define as, it is obtained by cooling the gas that is formed by during the destructive distillation of coal with normal temperature.
Check this –
What is coal tar distillation?
When coal is subjected to destructive distillation, it yield coal gas, and coal tar. coal gas is mainly used as a fuel.
Coal tar when subjected to fractional distillation gives following different product.
The light oil on the further fractional distillation yields various fraction & based on temperature. difference these are separated as benzene, toluene, xylene, etc.
The same is applied to other fraction, the products from these distillations are used to synthesize intermediates which are responsible for manufacture of dyes.