Dehydration of 1,5-pentanediol over rare earth oxides

Vapor-phase catalytic dehydration of 1,5-pentanediol was investigated over rare earth oxides (REOs) at 325–450 °C. The conversion of 1,5-pentanediol over REOs calcined at 700 and 800 °C was higher than that calcined at 500 °C. Sc2O3, Yb2O3, and Lu2O3 with cubic bixbyite structure showed the selectivity to 4-penten-1-ol with higher than 74 mol%, while REOs with hexagonal and monoclinic structures showed the selectivity with less than 50 mol%. Especially, Yb2O3 and Lu2O3 calcined at 1000 °C showed high formation rate of 4-penten-1-ol per specific surface area over 1 mmol h−1 m−2 at 400 °C. In the Yb2O3 catalyst calcined at 800 °C, the conversion of 1,5-pentanediol was increased up to 74.4 mol% with increasing contact time, together with stable selectivity to 4-penten-1-ol of 71.8 mol%. In comparing the reactivity of alkanediols to form the corresponding unsaturated alcohols over Yb2O3, we found the reactivity of alkanediols into the corresponding unsaturated alcohols was the following order: 1,4-butanediol > 1,3-diols ≫ 1,5-pentanediol ≫ 1,6-hexanediol.

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► The dehydration of 1,5-pentanediol to 4-penten-1-ol over rare earth oxides was studied.
► Sc2O3, Yb2O3, and Lu2O3 showed the selectivity to 4-penten-1-ol with higher than 74 mol%.
► Reactivity of alkanediols over Yb2O3 varies with the carbon number of diols.
► The reactivity order: 1,4-butanediol 1,3-diols ≫ 1,5-pentanediol ≫ 1,6-hexanediol.