The steam cracking of naphtha to produce buta-1,3-diene (BD) needs a high temperature over 700 oC and shows a low selectivity. The oxidative dehydrogenation (ODH) of C4 fraction is attracting much attention. In our laboratory, it was reported that the copper ferrite catalyst showed the high activity even at 270 oC for the ODH of but-1-ene. However, the complete oxidation of BD and n-butene also proceeded, and Cu2O appeared in the used catalyst. In this work, in order to clarify the factors for the complete oxidation and the ODH of but-1-ene, the effects of various copper oxide catalysts such as CuO, Cu2O, and CuFe2O4 on the ODH were examined. The ODHs of but-1-ene were carried out with a fixed-bed flow reactor under O2 atmosphere at 270 oC. The CuO and CuFe2O4 catalysts were prepared by the impregnation method using an activated carbon (AC) as a support. Notations are CuO/AC and CuFe2O4/AC. The Cu2O catalyst was prepared by the precipitation method. When the CuFe2O4/AC was used for the ODH of but-1-ene under O2 atmosphere, the highest BD yield of 8 % in this study was obtained, and this catalyst exhibited the CO2 selectivity of 40 %. CuO/AC and Cu2O catalysts showed the higher CO2 selectivity of 70 % and 60 %, respectively, than that of CuFe2O4/AC. According to XRD and XPS analyses of CuO/AC and Cu2O before and after the reaction, the almost of crystalline CuO phase changed mainly to Cu2O phase during the ODH, and the Cu2O phase was kept. These results indicated that the complete oxidation was caused by the Cu2O phase. In the case of CuFe2O4/AC, although Cu species in CuFe2O4 were also reduced to Cu2O, many divalent Cu species were maintained. Therefore, it was suggested that the maintenance of the high valence Cu species is important to produce the BD.

Oxidative dehydrogenation of but-1-ene with copper oxide catalyst

254th National Meeting (2017)

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