Abstract: Ru₃(CO)₉(TPPTS)₃ was used in the selective reduction of aromatic nitro compounds under COatmosphere in water/organic biphase system. It was found that the reaction was accelerated obviously by phase-transfer catalysts and the cetyltrimethylammonium bromide(CTAB) is the best one among them. Using o-ClC₆H₄NO₂ as a reactant, the influences of the concentration of CTAB, the concentration of NaOH, reaction temperature and COpressure on the catalytic properties of Ru₃(CO)₉(TPPTS)₃ were studied. Under the conditions of 120 ℃, p_co =4 MPa, 3 mol/L NaOH, 8 h, both the conversions of o-ClC₆H₄NO₂ and the selectivity of o-ClC₆H₄NH₂ were 99.9%. The reductions proceeded with a markable activity and selectivity toward aromatic nitro group as C-O, C-Ngroups present in the substrate. After 3 times recycle of the catalyst the conversion of o-ClC₆H₄NO₂ and the yield of o-ClC₆H₄NH₂ were more than 92%.

Key words: Water-soluble phosphine ruthenium complex, Water/organic phase transfer catalysis, Aromatic nitro compounds, CO selective reduction