Decarboxylation of fatty acids to fuel additives over a 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 the decarboxylation (DCO) of lauric acid under liquid-phase conditions. The external pockets of the MWW zeolite provided anchoring sites for Ru species and facilitated strong interactions with the reactant molecule (lauric acid). The in situ formation of metallic Ru under the reaction conditions of 0.05 g of catalyst, 16 mmol of lauric acid, 3 MPa and 190 °C, combined with the presence of acidic centres, contributed to the excellent catalytic activity observed in lauric acid decarboxylation. High-resolution transmission electron microscopy and powder XRD confirmed the uniform dispersion of Ru nanoparticles within the supercages of the MWW framework. Catalytic studies revealed that the well-dispersed Ru species on the MWW framework led to high selectivity for the decarboxylated product n-undecane (54%) at 190 °C and 3 MPa H₂ pressure.