The Friedel-Crafts reaction Of PCl3 and benzene in [trEHAm]Cl-XAlCl3 ionic liquids (ILs) was investigated for clean synthesis of dichlorophenylphosphine (DCPP). A simple product isolation procedure was achieved, and the effects of ILs composition, reactant composition. reaction time and quantity of ILs on this reaction were studied. The [trEHAm]Cl-XAlCl3 ionic liquids gave this reaction a green character. A catalytic mechanism was proposed as well, (C) 2003 Elsevier B.V. All rights reserved.