Ru3(CO)9(TPPTS)3催化的水/有机两相芳香硝基化合物CO选择性还原的研究

将水溶性膦/钌配合物Ru₃(CO)₉(TPPTS)₃(TPPTS:三苯基膦三-间磺酸钠)用于以CO为还原剂的水/有机两相芳香硝基化合物选择还原为芳胺的反应,发现相转移催化剂对反应有明显的促进作用,其中以添加十六烷基三甲基溴化铵(CTAB)的效果最好.以邻氯硝基苯为底物考察了相转移催化剂浓度、NaOH浓度、反应温度、压力等对反应转化率和选择性的影响.当反应条件为120℃,4MPa,3mol/LNaOH时,反应8h,邻氯硝基苯的转化率和邻氯苯胺的选择性均可达到99.9%.而且对含有羰基、氰基的芳香硝基化合物也有很高的活性和选择性.催化剂循环3次后,邻氯硝基苯的转化率和邻氯苯胺的收率仍可达到92%.

Studies of CO Selective Reduction of Aromatic Nitro Compounds in Water/Organic Phases by Using Ru3(CO)9(TPPTS)3

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%.