Catalytic transfer hydrogenation of furfural using mechanically activated MgO as catalyst†

Abstract

Several MgO materials have been prepared throughout wet flow semi-continuous mechanochemical treatment of the Mg(OH)₂ precursors and their subsequent calcination. This mechanochemical treatment of the precursors has shown a clear influence on the textural properties and the amount and strength of basic sites of the MgO catalysts after its calcination, obtaining higher values than that observed in a MgO sample synthesized without mechanochemical treatment. An in-depth investigation was conducted on the effects of the mechanochemical treatment on the catalytic performance in the catalytic transfer hydrogenation of furfural, and a positive effect on the activity of the catalysts was found after short mechanochemical treatment times. The highest conversion values at shorter reaction times were obtained after a mechanochemical treatment of 15 min, reaching a furfuryl alcohol yield of 79% after 2 h of reaction at 90 °C, using 2-propanol as both hydrogen donor and solvent. This data notably improves that obtained for the untreated material, which only reaches a conversion of 48% under the same experimental conditions. The stability of the material in the reaction media as well as their reusability were also investigated, and the interaction nature of 2-propanol with the MgO surface has been elucidated by attenuated total reflection spectroscopy and 2-propanol adsorption studies.