Influence of Brønsted acid sites on the product distribution in the hydrodeoxygenation of methyl laurate over supported Ru catalysts

The production of biofuels (hydrocarbons) from renewable biomass resources has attracted much attention in the fields of green energy and sustainable chemistry. Herein, catalytic hydrodeoxygenation of methyl laurate (n-C11H23COOCH3) to produce hydrocarbons n-C12H26 and n-C11H24 has been investigated over Ru dispersed on acidic supports H-ZSM-5, Al2O3 and SiO2, and the reaction rate and the product distribution were discussed and correlated with surface Brønsted and Lewis acid sites and active Ru species in detail. The reaction rate at the initial stage increased with the amount of the total acid sites, and the ratio of n-C12H26/n-C11H24 and the selectivity to n-C12H26 were positively correlated with the amount of Brønsted acid sites. The Ru active species presented to be more electron-deficient on the catalysts with a larger amount of Brønsted acid sites on which an η1-(O) adsorption configuration of 1-C11H23CHO was confirmed, which favoured the formation of n-C12H26, thus varying the product distribution. Besides, Brønsted acid sites could provide protons to promote the hydrogenolysis of n-C11H23COOCH3 and the following dehydration to produce n-C12H26.