Catalytic Performances of the Nano FeCo Solids for Biofuel Additives Production: Incorporation of Promoter Effects on the Stability of the Catalysts
Antonio J. Martins de Farias, Antonio N. da Silva, Alcinéia C. Oliveira, José Vitor C. Carmo, Gilberto D. Saraiva, Raí F. Jucá, Marco A. Morales, Rossano Lang, José Jiménez-Jiménez, Enrique Rodrı́guez-Castellón
Abstract
Nanosized Fe-based solids exhibited favorable features for catalytic application in the solvent-free acetalization of glycerol with aldehydes for biofuel additives production. The physicochemical properties of solids by SEM–EDS, TEM, EPR, XRD, Raman, Mössbauer, and FTIR measurements and XPS analysis were correlated with the catalytic properties. Among the different approaches utilized for the synthesis of the FeCo-based solids, the copolymer-assisted coprecipitation method showed glycerol conversions superior to 20%, being stable materials rather than the sol–gel solids that had 1,3-dioxolane selectivity more than 45%. The effects of the incorporation of a third promoter i.e, Mn, Mo, or Cu in the nanosized FeCo catalysts showed that Cu incorporation gave solids with low activity, whereas the insertion of Mn and Mo achieved the best catalytic results. The presence of low amounts of Mn, predominantly as an electronic promoter to FeCo, revealed much better performance in the presence of furfuraldehyde compared with benzaldehyde and butyraldehyde substrates. The iron-containing manganese catalyst benefits the charge transfer of these Mn species to Fe 3+ /Fe 2+ or Co 3+/ Co 2+ in the acetalization glycerol reaction.