title: Glycerol hydrogenolysis promoted by supported palladium catalysts.
abstract: Catalytic hydrogenolysis, with high conversion and selectivity, promoted by supported palladium substrates in isopropanol and dioxane at a low H(2) pressure (0.5 MPa), is reported for the first time. The catalysts, characterized by using BET isotherms, transmission electron microscopy (TEM), temperature-programmed reduction (TPR), powder X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), were obtained by coprecipitation and impregnation techniques. The coprecipitation method allows catalysts with a metal-metal or a metal-support interaction to be obtained, which enhances the catalytic performance for both the conversion of glycerol and the selectivity to 1,2-propanediol. Analogous reactions carried out with catalysts prepared by using impregnation are less efficient. A study of the solvent and temperature effect is also presented. The obtained results allow the hydrogenolysis mechanism to be inferred; this involves both the direct replacement of the carbon-bonded OH group by an incoming hydrogen or the formation of hydroxyacetone as an intermediate, which subsequently undergoes a hydrogenation process to give 1,2-propanediol. Finally, catalytic tests on a large-scale reaction at a higher H(2) pressure and recycling of the samples were carried out with the better performing catalysts (Pd/CoO and Pd/Fe(2)O(3) prepared by using coprecipitation) to verify possible industrial achievements.
authors.affiliation: Dipartimento MecMat, Facoltà di Ingegneria, Università Mediterranea di Reggio Calabria, Loc. Feo di Vito, 89122 Reggio Calabria, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Musolino
authors.forename: Luciano Antonio
authors.initials: LA
authors.lastname: Scarpino
authors.forename: Francesco
authors.initials: F
authors.lastname: Mauriello
authors.forename: Rosario
authors.initials: R
authors.lastname: Pietropaolo
mesh_terms: D002384:Catalysis; D005990:Glycerol / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D019946:Propylene Glycol / Q000138:chemical synthesis*
chemical_list: D010165:Palladium; D019946:Propylene Glycol; D006859:Hydrogen; D005990:Glycerol