Low temperature transformation of lignocellulose derived bioinspired molecules to aviation fuel precursor over magnesium–lanthanum mixed oxide catalyst

Abstract

Basic magnesium–lanthanum (Mg–La) mixed oxide materials with tunable interaction between Mg and La oxides were prepared for the low temperature production of green diesel and jet fuel intermediates via aldol condensation reaction. The prepared materials were thoroughly analysedby microscopic and spectroscopic techniques to elucidate its structural properties, including the determination of surface area and basic strengths. Among the tested materials, ML-3 catalyst reflects superior activity for CC bond formation between 5-hydroxymethylfurfural (HMF) and acetone, exhibiting >99% HMF conversion and 89% yield of the precursory C9 4-[5-(Hydroxymethyl)-2-furanyl]-3-butene-2-one product (HAc). Higher conversion and better product selectivity of ML-3 catalyst ascribe to the higher basic strength, moderate surface area and strong interaction between both the metals (Mg and La) in their mixed oxide forms. To understand the role of active sites, zeroth, first and second order kinetics were plotted, and a possible mechanism of CC bond formation was hypothesized. In order to rationalize the role of active ML-3 catalyst, HMF (and furfural) chain lengths were extended with different carbonyl compounds leading the formation of branched and cyclic chain (C9–C15) hydrocarbon precursors.