Decarboxylation of Fatty Acids to Fuel Additives Over Ruthenium Dispersed MWW Zeolite Framework

Abstract

The selective decarboxylation of biomass-derived fatty acids to gasoline additives was performed using zeolite-based heterogeneous catalysts. Ruthenium (Ru) dispersed within the medium pore channels and 12-membered external pockets of the MWW zeolite framework was prepared and evaluated for hydrodeoxygenation (HDO) of lauric acid under liquid-phase conditions. The external pockets of MWW zeolite provide anchoring sites for Ru species and facilitate strong interactions with the reactant molecule (lauric acid). The in situ formation of metallic Ru under reaction conditions (0.05 g of catalyst, 16 mmol lauric acid, a hydrogen pressure of 3 MPa, 190 °C), along with hydrogen spillover and acidic centres, contributed to the excellent catalytic activity in acid deoxygenation. The uniform dispersion of Ru on the supercages of MWW framework was further supported by high-resolution transmission electron microscopy and powder XRD analysis. Catalytic studies revealed that MWW framework containing Ru species followed two distinctive reaction pathways: decarboxylation (DCO) and hydrodeoxygenation (HDO), yielding n-undecane (54%) and n-dodecane (31%), respectively, at 190 °C and 3 MPa.