Now the light oil is washed with water. Due to which acidic elements are removed. In this way, efficient distillation of purified oil is done, which gives the following effect.
90% benzoyl (80 – 110°C) – 90% benzoyl means that distillation of 100 ml at 100°C gives 90 ml distillate. It contains 70% benzene and the rest toluene and xylene.
50% benzoyl (110 – 140°C): 50% benzoyl means that distillation of 100 ml at 100°C gives 50 ml distillate, it contains 45% benzene and the remaining toluene, xylene and other hydrocarbons.
Solvent naphtha or benzoic 140 – 170°C – It is used in dissolving dyes, rubber and resins, on re-effecting distillation of the above constituents, benzene at 80°C gives toluene at 110°C and xylene at 135°C.