Reduction of 2,4,6-trichlorophenol with zero-valent zinc and catalyzed zinc

Reductive dechlorination of 2,4.6-trichlorophenol (2,4,6-TCP) was conducted with Zn and Zn bimetals, Pd/Zn, Ni/Zn, Cu/Zn, Pt/Zn. Zn showed relatively low reaction rate toward 2,4,6-TCP, while Pd/Zn had dramatically increased reactivity and other bimetals had higher reaction rates than that of plain zinc. Phenol and less chlorinated phenols were found as dechlorination products. Pd/Zn produced cyclohexanone which is a product of aromatic ring reduced. Surface area normalized kinetic constants and second metal contents normalized kinetic constants were calculated and compared. Two mechanisms, mainly catalytic activation and enhanced corrosion, were proposed for the reactivity enhancement. (C) 2008 Elsevier B.V. All rights reserved.