Polyethylene glycol-400（PEG-400）grafted in silica（SiO2）support as macromolecule ligand was synthesized

and the structure of the ligand was characterized by IR spectroscopy.The complex of silica-supported PEG-400 and molybdenum(Ⅵ)dioxo(2

4-pentanedione)［shortened form

SiO2-PEG-Mo(Ⅵ)］was for the first time synthesized and characterized by infrared spectroscopy.The possible structure of the complex was discussed.As a catalyst

SiO2-PEG-Mo(Ⅵ)complex was used in epoxidation process of cyclohexene

and its catalytic activity and selectivity was also investigated.Experimental results showed that the complex possessed excellent activity and selectivity for epoxidation of cyclohexene.A new analysis method of the amount of Mo in the catalyst and the analysis of epoxycyclohexane by gas chromatography were set up.For n(t-BuOOH) = 0.1 mol

n(cyclohexene)∶n(t-BuOOH)=3.5∶1

the volume of solvent was about 10 ml

reaction temperature 80 ℃

reaction time 60 min，and the amount of SiO2-PEG-Mo(Ⅵ)complex catalyst was 0.5 g.In this reaction condition

based on t-BuOOH

the yield of epoxycyclohexane was more than 99.2%

the purity of epoxycyclohexan was about 99.5% by GC analysis.The catalyst recycled for 3 times still possessed high catalytic activity and selectivity

and the yield of cyclohexene oxide approached 99% in the above-mentioned reaction condition.