Catalytic aldol condensation of bio-derived furanic aldehydes and acetone: Challenges and opportunities

Bio-derived furfural and 5-hydroxymethylfurfural can be combined with acetone to yield aldol condensation products that may serve as biofuel and polymer precursors. We have explored different catalytic systems to obtain and purify each product in the most efficient way. The results of the catalytic tests of the cross-condensations and of the self-condensation of acetone allowed the comparison of the different reactivity of the two aldehydes. Online and in situ / operando ATR-IR was used to monitor the reaction over time and to study the interaction of the reaction species with the solid catalyst, especially the formation of deactivating organic matter that covers the surface, which is a major issue in heterogeneous condensation processes. In situ NMR was used to study the ongoing reaction, assessing its stereoselectivity, and to study the behavior of deuterated species in the catalytic system. Finally, the preparation of C14, a hetero-double-condensation product, was also explored. • The condensations of acetone with furfural and HMF were studied and compared. • IR and UV-Vis studies of the recovered catalysts point to surface polymerization. • The interaction of species with the catalysts was studied by in situ / operando ATR-IR. • The behaviour of the aldol intermediates was studied by in situ 1 H-NMR. • The selective preparation of a C14 product was studied.