Dehydration of 1,5-Pentanediol over Na-Doped CeO₂ Catalysts

The effects of CeO₂ doped with Na on the dehydration of 1,5-pentanediol were studied by using a fixed-bed reactor at two different temperatures (350 and 400 °C) and atmospheric pressure. For characterization, BET surface area, hydrogen temperature-programmed reduction, CO₂ temperature-programmed desorption, and diffuse reflectance infrared Fourier transform spectroscopy techniques were utilized. The conversion of the diol on CeO₂ was found to depend on Na loading. The selectivity to the desired product (i.e., unsaturated alcohol) increased and the selectivity to undesired products (i.e., tetrahydropyran, tetrahydropyran-2-one, cyclopentanol and cylopentanone) decreased with increasing Na content on CeO₂. The basicity of hydroxyl groups or surface oxygen on CeO₂ was altered with the addition of Na, and controlled the dehydration reaction pathway.