Catalytic oxidation of crude glycerol using catalysts based on Au supported on carbonaceous materials

Authors:  Sonia Gil, Miriam Marchena, Carmen María Fernández, Luz Sánchez-Silva, Amaya Romero, José Luís Valverde

Abstract:
Au catalysts supported on different carbon materials, such as graphite (G, 10 m² g−1), ribbon-type carbon nanofibers (CNF-R, 109 m² g−1), and carbon nanospheres (CNS, 3 m²g−1), were prepared by the sol–gold method using tetrahydroxymethyl phosphonium chloride as the reducing agent. Different techniques were employedto characterize boththe supports andthefinalAucatalysts: atomic absorptionspectrometry,transmission electron microscopy,thermogravimetric analysis, X-ray diffraction, elemental analyses, N₂ adsorption–desorption analysis,temperature-programmed reduction, and temperature-programmed decomposition. Au catalysts were tested in the liquid phase by selective oxidation of both commercial and crude glycerol,the latter obtained from the manufacture of biodiesel. Catalytic results obtained with commercial glycerol showed that the product distribution was dependent on the nature of the support and consequently on the Au particle size. The highest catalyst activity was achieved using highly crystalline carbon supports, supporting small-size (highly dispersed) Au particles. Accordingly the graphite-based catalyst exhibited higher catalytic activity than the CNF-R-based one. Catalytic results similar to those obtained with commercial glycerol were obtained when testing the stream resulting from a low cost neutralization procedure of the crude glycerol.

Keywords:
Carbonaceous materials
Gold supported catalysts
Liquid-phase oxidation of glycerol
Crude glycerol
Purification

Published in: Applied catalysis A: General  (Volume 450, Pages 1-274, 15 January 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

Catalytic oxidation of crude glycerol using catalysts based on Au supported on carbonaceous materials

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