LAUSR

Catalytic decarbonylation is an underexplored strategy for deoxygenation of biomass-derived aldehydes due to a lack of lowcost and robust heterogeneous catalysts able to operate in benign solvents. A family of Pd functionalized hydrotalcites (Pd-HTs) were synthesized, characterized, and applied to the decarbonylation of furfural, HMF, and aromatic and aliphatic aldehydes under microwave conditions. This catalytic system delivered enhanced decarbonylation yields and turnover frequencies, even at a low Pd loading (0.5 mol%). Furfural decarbonylation was optimized in a benign solvent (ethanol) compatible with biomass processing; HMF selectively affords excellent yields (93 %) of furfuryl alcohol without humin formation, however longer reaction favors furan via tandem alcohol dehydrogenation and decarbonylation. Yields of substituted benzaldehydes (37 - 99 %) were proportional to the calculated Mulliken charge of the carbonyl carbon. Activity and selectivity reflect loading-dependent Pd speciation. Continuous flow testing of the best Pd-HT catalyst delivered good stability over 16h on stream, with near-quantitative conversion of HMF.