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Study On Catalytic Dehydrogenation Of Cyclohexanol To Cyclohexanone Over Supported Cu2O Catalyst

Posted on:2008-01-24Degree:MasterType:Thesis
Country:ChinaCandidate:N LiuFull Text:PDF
GTID:2121360215988130Subject:Industrial Catalysis
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Catalytic dehydrogenation of cyclohexanol to cyclohexanone is an industriallyimportant reaction in the manufacture of caprolactam, which is used as a material for thesynthesis of nylon. Besides, cyclohexanone is also widely used as an organic solvent, andin the synthesis of rubber and industrial paint. It plays an important role in chemical andpetrochemical industries.The content of this thesis is divided into three parts. Firstly, the Cu2O/MgO catalystwas prepared by chemical reduction combined with impregnation method, and the effectof preparation condition on its catalytic properties for cyclohexanol dehydrogenation wasstudied. The catalyst was characterized by N2 adsorption, X-ray diffraction, transmissionelectron microscopy, X-ray photoelectron spectroscopy, Auger electron spectroscopy, andtemperature- programmed reduction. The results show that the activity of the catalystreaches the maximum at a Cu2+: N2H4·H2O: NaOH- molar ratio of 1:1:2, the conversionof cyclohexanol reaches 81.6%. The activity of the Cu2O/MgO catalyst is much higherthan that of the traditional Cu/MgO catalyst.The effects of different proportion of MgO/sepiolite in composite carrier andpreparation method of MgO on the properties of supported Cu or Cu2O catalyst forcyclohexanol dehydrogenation were studied in the second part of the thesis. The catalystwere characterized by means of N2 adsorption, X-ray diffraction(XRD), Infra-redspectroscopy(IR), NH3 temperature programmed desorption (NH3-TPD) and temperatureprogrammed reduction(TPR), respectively. The results show that the activity ofCu/MgO/sepiolite is higher than that of Cu/MgO when the mass ratio of sepiolite in thecomposite carrier is up to 20~40%, but the Cu2O/MgO/sepiolite exhibits lower activitythan Cu/MgO. The specific surface areas of Cu2O catalyst supported on MgO whichprepared by homogenous precipitation method and sol-gel method are higher than that ofCu2O supported on common MgO. The activity of Cu2O catalyst supported on MgOprepared by sol-gel method is the highest among the three catalysts.In the last, the Cu2O/MgO catalyst was modified by transition metals, noble metalsand rare earths. The results show that Mn and Ni are good additives among transition metals for the Cu2O/MgO catalyst, the conversion of cyclohexanol on the catalystmodified by Mn and Ni reaches 91.9%and 91.2%respectively. But the selectivity ofcatalyst modified by Ni decreases. The activities of catalysts modified by noble metals allincrease, especially by Ru and Pt, the conversion of cyclohexanol on the catalystmodified by Ru and Pt reaches 93.3%and 90.6%respectively. When the catalyst ismodified by rare earths, Ce and Sm can improve the activity of catalyst, the conversion ofcyclohexanol reaches 92.9%and 92.1%respectively.The supported Cu2O catalyst was applied to cyclohexanol dehydrogenation in thisthesis. The activity and selectivity of catalyst were improved by optimizing carriers andadding additives. These studies will provides some reference to create new catalyticsystem for cyclohexanol dehydrogenation.
Keywords/Search Tags:cuprous oxide, magnesia, sepiolite, composite carriers, modification, catalytic dehydrogenation of cyclohexanol, cyclohexanone
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