Effect of Reduction Protocol of Pd Catalysts on Product Distribution in Furfural Hydrogenation

Abstract Single step conversion of furfural to ring hydrogenation and decarbonylation products, 2‐methyltetrahydrofuran (2‐MeTHF) and tetrahydrofuran (THF) in high selectivity was achieved by controlling the particle size of Pd/C catalyst. The particle size variation of Pd/C catalysts in the range of 3.8 to 22 nm could be achieved by employing different reducing agents. Of particular interest was the NaBH 4 reduced catalyst (Pd−B/C), which gave the lowest crystallite size of 4.8 nm due to incorporation of B into the inner lattices of Pd−Pd. This phase was evidenced by a characteristic XRD peak of Pd−B at 2θ=38.85 O as well as a shift of (111) peak (40.07 O ) of Pd towards the lower value (39.8 O ). As compared to formaldehyde reduced catalyst (Pd−F/C), Pd−B/C catalyst completely suppressed the formation of furfuryl alcohol to give > 65 % selectivity to 2‐MeTHF and THF. At 180 O C, almost equal distribution of side chain hydrogenation and ring opening products, 2‐MF (45 %) and PeDO (37 %), respectively, was observed while, higher temperature clearly favoured ring hydrogenation and decarbonylation reactions to give 2‐MeTHF and THF.