Hydrodeoxygenation of glycerol with in situ H2 formation over Pt catalysts supported on Fe modified Al2O3: effect of Fe loading

BACKGROUND: Glycerol hydrodeoxygenation to 1,2-propanediol is a reaction of commercial and environmental significance. However, the need for hydrogen supply is a main drawback of the process. This study aims at the development of effective catalysts for glycerol hydrodeoxygenation with in situ H-2 formed. Pt/Al2O3 and Pt/Fe2O3-Al2O3 catalysts with different Fe/Pt ratios were synthesized and evaluated. N-2 physisorption, XRD, TPR-H-2, TGA and DRIFTS-CO characterization techniques were used. Main focus was given on catalyst reusability, while a parametric study was also performed. RESULTS: Fe addition promotes catalysts activity. Characterization showed that there is an electron interaction between Pt and Fe which is responsible for this enhancement. However, Fe/Pt ratio and reduction temperature affect catalyst performance. The increase of Fe loading leads to lower H-2 formation rates but also to more stable catalyst performance. The most promising results were achieved over the Fe richer catalyst which exhibited 51.5% 1,2-propanediol selectivity, 93.8% glycerol conversion, under 3.5MPa N-2, at 250 degrees C, 1 h and pre-reduction at 200 degrees C. CONCLUSION: The presence of Fe in Pt/Al2O3 catalysts was proved decisive for the combined cycle of glycerol hydrodeoxygenation-aqueous phase reforming. The high activity and the stable performance in aqueous medium may render these materials as suitable catalysts for various liquid phase hydrodeoxygenation reactions. (C) 2017 Society of Chemical Industry