Alcohol Decomposition as Reaction Test to Analyse the Catalytic Properties of 4f Oxides

The decomposition of 1-propanol and 2-propanol over a series of eight lanthanide oxides (La2O3, CeO2, Pr6O11, Sm2O3, Eu2O3, Dy2O3, Ho2O3 and Yb2O3) is studied. The activity data were obtained in a flow reactor at normal pressure. The alcohol partial pressure was around 69KPa (520 Torr). The conversions were generally lower than 10%. Dehydrogenation to carbonylic products and dehydration to propylene were the only reactions here observed. For both alcohols, the differences of activity among the eight oxides, though significant, were within one order of magnitude. Contrary to suggested in the literature no simple relationship was found between the position of 4/element in the series and the catalytic activity of the corresponding oxides. No definite patterns of apparent activation energies or selectivity data were observed either. When the reactivities of 1-propanol and 2-propanol towards dehydration are compared, significantly lower values are found for the former alcohol. The origin of this influence of the alcohol structure, as well as the chemical meaning of the observed linear relationships between Ea and log A, are discussed. © 1983, R. Oldenbourg Verlag, Munchen