Hydrodechlorination of dichlorobenzenes and their derivatives over Ni–Mo/C catalyst: Kinetic analysis and effect of molecular structure of reactant

The kinetics of the catalytic hydrodechlorination (HDC) process of selected dichlorobenzenes (DCBs), dichlorotoluenes (DCTs) and dichlorodiphenyls (DCDs) was studied in the presence of a sulphided carbon-supported Ni–Mo catalyst. The HDC runs were performed in a magnetic stirred batch reactor in the range of 210–230 °C under the hydrogen pressure of 3 MPa. The kinetic constants were evaluated and the reaction network was proposed assuming the pseudo-first order kinetics of dechlorination process. The HDC of aromatic dichloroderivatives proceeded via a network of sequential–parallel reactions. At 210 °C DCBs, DCTs and DCDs followed mainly the pathway of direct transformation to respective aromatic hydrocarbon. At 230 °C, the contribution of sequential dechlorination to monochloroderivative became more predominant.

Research highlights
► Susceptilibity of chloroaromates to dechlorination over NiMo catalyst was studied.
► The kinetics constants were evaluated and the reaction network was proposed.
► Hydrodechlorination reaction proceeded via network of sequential–parallel reactions.
► At 210 °C dichloroaromates mainly followed a direct dechlorination to hydrocarbon.
► At 230 °C the contribution of sequential dechlorination was predominant.