LAUSR

Abstract Liquid phase conversion of glycerol was investigated in a semi-batch system. γ-Al2O3 supported Ni, Co, Cr and Zn catalysts (13 wt.%) were prepared using an emulsion with ethylene glycol (EG) and characterized by XRD, TPR, BET, and XPS techniques. After preparation of catalysts, reduction-passivation was performed, and metallic phases of Ni and Co catalysts were observed. For Cr and Zn catalysts, Cr2O3 and ZnAl2O4 phases were observed, respectively, which lead to a low activity. Co(EG)RP catalyst deactivated after 100 min of reaction. Ni(EG) catalyst showed the best activity and stability with a glycerol conversion of 38% after 6 h of reaction. Semi-batch reactor considerably favored the selectivity to liquid and gas products, even at 250 °C, as compared to batch reactor. Ni(EG)RP and Co(EG)RP catalysts favored the formation of hydrogen, carbon monoxide, water, important high added value starting/intermediate industrial products such as 1,2-diformyloxypropane, pinacolone, acetol, and epoxides (glycidol, 2-(ethoxymethyl)oxirane and 2-(propoxymethyl)oxirane) representing between 50 and 70% of the total yield, respectively. Finally, in the recycle tests without a stage of reactivation of the Ni catalyst, catalytic activity decreased about 50%, from 405 to 206 g of converted glycerol per gram of Ni°, showing a reusability up to three cycles, which represents an economy of energy, time and H2 spending for this type of system.