Recycle and catalytic oxidation of hydrogen chlorination during toluene chlorination

The direct recycle of chlorine was studied in this paper. The hydrogen chloride from the by-product of toluene photo chlorination was directly used as oxidation reaction raw gas. After being simply treated, the mixed gases from oxidation reactor were inducted into chlorination reactor to chlorinate toluene. The chromic oxide catalyst was prepared by impregnating γ-Al₂O₃, which has a stable activity and there was no obvious deactivation after 150 hours activity test. High HCl conversion of 80% was obtained under the conditions of the reaction temperature of 360°C, the raw material HCl/O₂ mole ratio of 1:1, feed space time of 5 h. The chlorine recycling result shows that it is feasible that the mixed gases from oxidation reactor can be directly utilized in toluene chlorination with some proper catalyst. The chlorine from oxidation reactor utilization ratio could reach 100%.