Abstract: A series of Cubased catalysts modified with alkali metal M (M=Li,Na,K,Cs) was prepared via wet impregnation method. The loading of copper was fixed at 5% (mass fraction); the molar ratio of copper to alkali metal was 5 ∶1. The catalysts were used in the dehydrogenation of cyclohexanol to elucidate the effects of the additives on the catalytic properties of copper. The catalysts were characterized by means of XRD, BET, H₂-TPR, NH₃-TPD and CO₂-TPD. The results indicate that the statuses of copper oxide species on the modified catalysts were changed. The number of acidic sites on the modified catalysts surface was decreased. Accordingly, the selectivity of cyclohexene was remarkably de creased and the selectivity of cyclohexanone was increased (>99%). The Cu-K/SiO₂ catalyst showed a highly catalytic activity and a highly selectivity of cyclohexanone.The interaction between copper and K additive prevented the growing up of copper, and improved the stability of catalyst.

Key words: cyclohexanol, cyclohexanone, dehydrogenation, alkali metal