Cu-Mn-Si catalysts with copper-manganese oxides as the main constituents and silica dioxide as the supports were prepared by co-precipitation method. The performance of the catalysts for the dehydrogenation reaction of the 2-butanol to methyl ethyl ketone was tested. The effects of Cu and Mn ratios on the catalytic performance were investigated. The catalysts were characterized by XRD, SEM, H2-TPR, TG, BET and XPS, to reveal the catalytic mechanism. The results showed that after adding the manganese, the copper-manganese complexes were formed in the catalysts, which effectively improved the activity of the catalysts. XRD results showed that a new phase of Cu-Mn complex was formed in the fresh catalysts, and reduced copper species appeared in the spent catalysts; TPR results showed that the reduction temperature of the catalysts could be reduced by adding appropriate amount of manganese; XPS results showed that the proportion of Cu++Cu0 can be increased in the fresh catalyst and that of Cu2+ in the spent catalyst can be decreased after the addition of manganese. When the mole ratio of Cu, Mn and Si in the catalysts was 0.8:0.2:1, the conversion of 2-butanol could reach 94.9%, and the selectivity of methyl ethyl ketone was 98%.

Li Zhang, ChaoQun Chen, XingTong Li and Ying Zhang