Dehalogenation of three chlorinated hydrocarbons: Amine‐assisted versus metal‐chelate assisted

Abstract

Metal chelate compounds of the type M(o‐OC₆H₄CH=NC₄H₉)₂ (M = Ni, Cu, Zn, etc.) participate in the dehalogenation of chloroform in the presence of ethylene diamine or tetramethyienediamine under homogeneous conditions and at elevated temperatures. Both an amine‐assisted and a metal‐assisted pathway are recognized on the basis of rate expression. In contrast, only an amine‐assisted pathway was observed for dichloromethane. Under non‐homogeneous conditions, however, i.e., using pure solvent, dehalogenation led to [M(diamine)_n]Cl₂ . Te importance of solubility as a driving force is considered as are the implications in the design of agents that will effect dehalogenation of chlorinated methanes.

Key words:

• Chloroform
• methylchloroform
• dichloromethane
• metal‐chelate compound
• nickel(II) complex
• Schiff base
• dehalogenation