Dehydration of Pentanediol over CeO₂, CeO₂-Ga₂O₃, and CeO₂-In₂O₃

Conversion of bio-oil from flash pyrolysis of biomass is a way to produce useful renewable feedstocks for the chemicals industry. Dehydration of pentanediol (1,5- and 2,4-pentanediol) was investigated over CeO₂, CeO₂-Ga₂O₃, and CeO₂-In₂O₃ catalysts at 250–350 °C. Adding Ga or In (20 mol%) improved the conversion of pentanediol over CeO₂, but adversely affected selectivity. In the base case, 1,5-pentanediol was converted on CeO₂ to 4-penten-1-ol and 1-pentanol, desired linear alcohols, together with unwanted cyclopentanol and cyclopentanone byproducts. Adding gallium or indium to ceria increased the selectivity towards undesired cyclized products like tetrahydropyran and tetrahydropyran-2-one due to increased acidity. In the base case, 2,4-pentanediol converted on CeO₂ to unsaturated alcohol (e. g., 3-penten-2-ol > 74 % selectivity), but adding Ga or In promoted acid-catalyzed cracking. Tuning the acid-base characteristics of ceria significantly alters the product distribution.