Hydrodechlorination of Chloroaromatic Compounds over Carbon-Supported Ni-Mo Catalysts

The hydrodechlorination (HDCl) process of 2-chlorodiphenyl, 4-chlorodiphenyl), chlorobenzene, chloronaphthalene and chloroanthracene was studied over a sulphided carbon-supported Ni-Mo catalyst (15 wt% MoO3, 5 wt% NiO) in a stirred autoclave at 260 degrees C and at a hydrogen pressure of 3 MPa. Activated carbons of different porosity characteristics were used as Ni-Mo catalyst support. A high chlorine removal for chloroorganic compounds was obtained in the presence of Ni-Mo/C catalysts, ranging from 73 to 99%. For monochlorodiphenyls, the HDCl degree is related to the position of the substituted chlorine atom. 4-chlorodiphenyl was converted to diphenyl to a higher extent compared with 2-chlorodiphenyl. Chloronaphthalene and chloroanthracene were shown to be more susceptible to chlorine removal than chlorobenzene. For comparison, chlorocyclohexane was tested in the HDCl reaction. The dechlorination of chlorocyclohexane proceeded at a much lower temperature compared to chlorobenzene.