Browsing by Author "Filipa Ribeiro, M."
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- Gas-phase conversion of glycerol to allyl alcohol over vanadium-supported zeolite betaPublication . Almeida, Ruben; Filipa Ribeiro, M.; Fernandes, Auguste; Lourenço, João PauloVanadium oxide supported beta zeolite (Si/Al = 25, 4% V) was used as catalyst for the one-pass gas-phase conversion of glycerol to allyl alcohol without any external reductant. The catalytic data strongly suggest a consecutive reactions path involving the dehydration to acrolein over the zeolite acid sites followed by a selective reduction through a hydrogen-transfer reaction. Acidity is expected to play a major role in what concerns the selectivity, as demonstrated by the catalytic results obtained by the impregnation of vanadium on a previously Cs-exchanged sample that achieved ca. 30% selectivity to allyl alcohol at ca. 20% glycerol conversion.
- Gas-phase dehydration of glycerol over hierarchical silicoaluminophosphate SAPO-40Publication . Fernandes, Auguste; Filipa Ribeiro, M.; Lourenço, J. P.Hierarchical silicoaluminophosphate SAPO-40 was synthetized using an organosilane acting as additional porogen agent. The structural, textural and acid properties of the new material were evaluated using XRD, 29Si and 27Al MAS NMR, SEM, N2 adsorption, pyridine adsorption followed by IR spectroscopy and thermal analyses. The evaluation of the catalytic performance in the dehydration of glycerol has evidenced a high activity and a very low deactivation rate. When compared with the conventional SAPO-40, this catalyst shows higher acrolein selectivity and a significantly longer catalytic lifetime.