Dehydration of 5-amino-1-pentanol over rare earth oxides

• Vapor-phase catalytic dehydration of 5-amino-1-pentanol was investigated.
• Rare earth oxides catalyzed the conversion of 5-amino-1-pentanol into 4-penten-1-amine.
• Tm2O3, Yb2O3, and Lu2O3 showed high conversion and high selectivity to 4-penten-1-amine.
• Yb2O3 calcined at 800 °C performed high formation rate of 4-penten-1-amine.
• The selectivity to 4-penten-1-amine exceeded 90% in H2 flow over Yb2O3 at 425 °C.

Vapor-phase catalytic dehydration of 5-amino-1-pentanol was investigated over various oxide catalysts including rare earth oxides (REOs). Over ordinary acidic oxides such as Al2O3, SiO2, SiO2-Al2O3, TiO2, and ZrO2, a cyclic amine such as piperidine was mainly produced at temperatures of 300 °C and higher. In contrast, basic REOs with a cubic bixbyite structure showed the catalytic activity in the conversion of 5-amino-1-pentanol to produce 4-penten-1-amine at 425 °C. In REO catalysts, Tm2O3, Yb2O3, and Lu2O3 showed the high conversion of 5-amino-1-pentanol and the high selectivity to 4-penten-1-amine. Especially, Yb2O3 calcined at 800 °C showed a high formation rate of 4-penten-1-amine with the selectivity of ca. 90% at 425 °C. In comparing the reactivity of several amino alcohols to form the corresponding unsaturated amines, Yb2O3 effectively catalyzed the dehydration of 6-amino-1-hexanol into 5-hexen-1-amine, whereas 3-amino-1-propanol and 4-amino-1-butanol were not effectively dehydrated due to the decomposition of the reactant.

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