RuCl₃-catalyzed Micheal Addition And The Nano Titanium Dioxide Preparation And Photocatalytic Properties

1. A RuCl₃-cataIyzed aza-Micheal addition was developed. RuCl₃ was found to be an efficient catalyst to hetero-Michael reaction of primary amine, secondary amine, aromatic amine, thiols, and carbamate. The amount of the catalyst (0.5 mol%) was much lower than that of conventionally metal catalyzed aza-Micheal addition (10 mol%). Different solvents, including dichloromethane, tetrahydrofuran, acetonituile, tolune, and DMF, were used as solvents and the catalytic properties were proved to be solvents independent. The catalyzed reaction was insensitive to air or moisture.2. The recyclable RuCl₃-PEG as an efficient and chemoselective catalyst for aza-Michael reaction was developed. The reaction was carried out under mild condition with high yield in the absence of other solvents, and RuCl₃-PEG could be readily recycled more than five times without obvious deactivation. For the first time, it was discovered that the sole mono-substituted products could be obtained in very high yield with primary aliphatic amines, and the aza-Michael addition proceeded smoothly with various substituted aromatic amines in the RuCl₃-PEG system.3. A series of homogeneously lanthanide doped nanosized mesoporous titania was successfully prepared by a sol-gel method. The results of XRD, BET and TEM revealed that the lanthanide doping not only inhabiting the anatase-to-rutile phase transformation, but remarkably depressed the sintering which are often taken place at high temperatures. The studies of photocatalytic activity show that the activity of homogeneously lanthanide doped nanosized mesoporous titania was significantly increased as compared with undoped titania. Both the concentration and calcination temperature exert important influences on the photoactivity. It is demonstrated that the good activity was still remained after the lanthanide doped titania was heated at 700℃ for 1h in air, which implicated a potential application of TiO₂ at high temperatures. The studies of RB degradation mechanism using UV and HPLC-MS indicated that the lanthanide ions doping into TiO₂ matrix played important roles to the RB photodegradation process.