| Photo-catalysis,as a green,mild and effective conversion technology,has shown good application in organic pollutant degradation and organic synthesis.Tetrabutylammonium decatungstate（TBADT）has been widely used in photo-catalytic selective oxidation of organic hydrocarbons by molecular oxygen due to its superior photocatalytic activity.A large amount of nitric oxide（N2O）generated in the industrial production of nitric acid and adipic acid is a harmful gas with strong greenhouse effect and a potential green oxidant.Due to the thermodynamic stability and kinetic inertness of N2O,it is an important and challenging research topic to activate N2O to participate in the selective oxidation of organic compounds to synthesize oxygenated products under mild conditions.To accomplish this challenging task,this paper aims to develop the doping of ruthenium compound or complex in TBADT to effectively construct novel hybrid catalysts for hybridizing molecules engineering（HME）strategy and to utilize highly active reducing species generated by the hybrid catalysts under visible light excitation,thus realizing its reduction activation N2O to participate in the selective oxidation reaction of hydrocarbons under room temperature and pressure.The main findings are as follows:1.The hybrid molecular engineering（HME）of ruthenium-doped non-vacancy TBADT using ruthenium compound or complex as dopants was studied.The effects of the doped ruthenium trichloride(RuⅡICl3),tris（2,2’-bipyridine）dichlororuthenium（Ⅱ）hexahydrate(RuⅡ（bpy）3Cl2·6H2O)on the synthetic quality and photophysical and photochemical properties of TBADT were emphatically investigated by UV-Vis,XPS,FT-IR,PL,CVs characterizations and so on.The results showed that the ruthenium hybrid catalysts can be successfully prepared by directly doping ruthenium compound or complex in the synthesis of TBADT.The doping of ruthenium compounds can not only improve the synthesis quality of TBADT,but also reduce the band gap energy and slightly adjust the frontier orbital energy levels,thus improving its visible light absorption efficiency and the separation efficiency of its photo-generated charge.The doping amount of ruthenium compound or complex can regulate the above hybriding effects and the optimal doping amount is 0.1 mol%.2.The N2O-based selective oxidation of organic compounds photo-catalyzed by the ruthenium-doped TBADT was studied using the self-assembled light reactor and a 35 W halogen-tungsten lamp as the built-in light source.The photo-catalytic effects of two kinds of hybrid catalysts(RuⅡICl3-TBADT and RuⅡ（bpy）3-TBADT)on N2O-based selective oxidation of cyclohexane was investigated.The influence of water and acid additives on their photo-catalytic properties was studied and the reaction conditions were optimized.The results indicated that TBADT showed poor photo-catalytic activity（3.3%conversion）in acetonitrile and the catalyst was prone to degradate to produce white precipitate under light irradiation.And various ruthenium hybrid TBADT catalysts can effectively catalyze this photo-oxidation reaction and there were not photo-degradation reaction upon the above DT that can achieve10-11%cyclohexane conversion.And the trace water in the reaction system plays a key role in photo-catalytic oxidation.More importantly,strong acidic additives can significantly improve the photo-catalytic performance of TBADT and the ruthenium hybrid catalysts.0.1%RuⅡ（bpy）3-TBADT can obtain 22.6%cyclohexane conversion and 90.2%cyclohexanone selectivity under optimized conditions.And the ruthenium hybrid catalysts also showed good photo-catalytic activity for N2O-based selective oxidation of toluene,ethylbenzene and benzyl alcohol.Based on the above photo-catalytic reaction results and related literature reports and combined with the UV-Vis spectral characterization results of the strongly redued species generated by the catalysts during photo-reaction process,we speculate that photo-generated and strongly reductive species of the hybrid catalysts play a key synergistic role in reducing activation N2O to complete the oxygen transfer（OAT）to hydrocarbon.3.Based on the above fact that TBADT can effectively photo-catalytic oxidize benzyl alcohol by N2O,it is further studied that its photo-catalytic oxidation of various alcohols to form corresponding aldehydes or ketones by N2O in acetonitrile,focusing the effects of the doped transition metal ions Ni2+,Co2+,Fe2+,Fe3+,the water,acidic solutions additives and reaction conditions on the photo-catalytic reaction of n-butanol.The results showed that TBADT can directly activate the N2O-based selective oxidation of n-butanol in acetonitrile in photo-catalytic system,achieving satisfying n-butanol conversion（ca.26%）along with 67.8%n-butanal selectivity.The doping of Co2+,Fe2+,Fe3+,especially Ni2+can improve the photo-catalytic acitivity of TBADT,and acetic acid,phosphoric acid,especially benzenesulfonic acid and sulfuric acid as acid additives can further improve the photo-catalytic efficiency of TBADT.This photo-catalytic reaction system was also adapted to the selective oxidation of other alcohols,including cyclohexanol and aromatic alcohols.The photo-oxidation activity of benzyl alcohol derivatives was influenced by their substituents on the benzene ring and the benzyl alcohol of electron-donating substituents are obviously beneficial to enhance their photo-oxidation activity.Based on the current photo-catalytic reaction results,the RCHOH radicals generated by the photo-oxidation of alcohol molecules（RCH2OH）are likely to play a synergistic role in the above OAT processes of N2O. |
