The selective oxidation of alcohol is considered as one of the most challenging reactions in organic synthesis for conversion of products of biomass processi ng. The long chain alkanols (Cs+) has merited much less attention than that of more reactive benzylic or C1-C4 aliphatic alcohols. Supported gold nanoparticles attract great attention due to unique catalytic activity at low temperature. Hexagonal mesoporous silica (HMS) is material characterized by large specific surface areas and pore sizes about 5 nm. A high hydrophobicity of HMS is a particularly advantageous property for gold-catalyzed aerobic oxidations because these reactions prod uce water and are usually performed in aqueous or alcoholic solutions. In this work, we investigate HMS, pure and mod ified with metal oxides (Ce, Fe), as supports of gold catalysts for the aerobic oxidation of 1-octanol under green process conditions. The support was mod ified with Fe and Ce in two ways: by introducing the promoters during the HMS synthesis or by post-synthesis impregnation. Their activity for liquid-phase oxidation of 1-octanol was tested. Octanal was the main product on every catalyst under the conditions tested (80ºC, oxygen flow at atmospheric pressure, solvent base-free heptane); the ester also formed but no acid was detected. The best activity was found on catalysts with post-synthesis impregnated supports, where additional phases of the corresponding oxides are detected by XRD. IR studies of CO adsorption on the catalysts revealed that is due to the different nature of the gold species, which are smaller (or positively charged) and deposited on the modifier oxide phase.

Trabajo presentado en el IX Simposio Internacional: Investigación Química en la Frontera, celebrado en Tijuana (México) del 20 al 22 de noviembre de 2013.

Peer Reviewed