The Study On Synthesis, Structure, Properties Of Vanadium/molybdenum Complexes

Cyclohexane oxidation is an important reaction in industry. Cyclohexanol andcyclohexanone are the main oxidized products of cyclohexane oxidation, and the materials forthe production of adipic acid and caprolactum, that are further used in the manufacturing ofnylon-6,6′, nylon-6, urethane foams, polyamide-6and lubricating additives. But the processof cyclohexane oxidation in industry shows low selectivity, much by-product, high-energyconsumption and environmental pollution. So it is importance to develop the highly efficientand environmental friendly catalysts.In this thesis, five vanadium complexes [(VO)3(μ2-O)2(2,2′-bipy)3(H2O)3(SO4)2]·3.5H2O(1),[VO(2,2′-bipy)2(SO)4)]·MeOH·H2O (2),[VO(C5H7O2)(BC9H7N6I3)]2(3),[V(dipic)(Hbdc)(2H2O)](4),[V2((dipic)2(H2btec)(4H2O)]·2H2O (5) and two molybdenumcomplexes [(TpMoO2)2(μ-O)]·CH3OH (6)、(Tp4-IMoO2)2(μ-O)(7)(2,2′-bipy=2,2′-bipyridine;dipic=2,6-pyridinedicarboxylic acid; Hbdc=1,3-benzene-dicarboxylic acid; H2btec=1,2,4,5-benzenetetracarboxylic acid Tp=tris(pyrazolyl)borate; Tp4-I=Hydrotris(4-iodinpyrazolyl)borate) were synthesized and characterized by the elementalanalysis, IR spectroscopy and UV spectroscopy. In particular, complexes1,2,6and7weresynthesized firstly, and characterized by single-crystal X-ray diffraction. In addition, thecomplexes6and7were also characterized by powder X-ray diffraction andthermogravimetric analyses (TG).In order to develop the novel catalysts, the catalytic properties of all complexes werestudied in the hydrogen peroxide promoted oxidation of cyclohexane under mild conditions(the optimized catalytic properties and reaction conditions were in Tab.1). The effects of avariety of factors, such as amount of acid and H2O2, the kind of solvent, as well astemperatures were also evaluated. In addition, according to the process of catalytic oxidation,a new reaction mechanism was proposed.