Dehydrogenation of cyclohexanol on copper-containing catalysts I. The influence of the oxidation state of copper on the activity of copper sites

The X-ray diffraction, X-ray photoelectron spectroscopy, IR spectroscopy of chemisorbed carbon monoxide and kinetic data have been employed to determi ne the active sites of copper-containing catalysts of both dehydrogenation of cyclohexanol to cyclohexanone and aromatization of cyclohexanol to pheno l. Two kinds of copper active sites of the cyclohexanol dehydrogenation rea ction to cyclohexanone have been revealed (monovalent copper and metallic c opper), and it has been shown that monovalent copper is significantly more active than metallic copper, and monovalent copper does not catalyze the ph enol formation. At the same time, metallic copper can play the role of acti ve sites not only in alcohol dehydrogenation to ketone but also in aromatiz ation of cyclohexanol to phenol. (C) 2000 Academic Press.