One-pot synthesis of confined structure Ru3Sn7 alloys on alumina for exceptionally rapid and selective hydrogenolysis of furfuryl alcohol to 1,5-pentanediol†

A facile one-pot synthesis of confined structure Ruthenium–tin alloy catalysts on alumina ((op)Ru–(x)Sn@Al₂O₃) has been developed for highly efficient and selective synthesis of 1,5-pentanediol (1,5-PeD) from furfuryl alcohol (FFalc). A series of (op)Ru–(x)Sn@Al₂O₃ (x = Sn co-loading; 0.37–2.65 wt%) catalysts were synthesised via a one-pot coprecipitation-hydrothermal method of a solution containing ruthenium chloride and tin chloride and a hydrargillite-type of aluminium hydroxide (Al(OH)₃) at 150 °C for 24 h, followed by reduction with H₂ at 400 °C for 2 h. The (op)Ru–(1.30)Sn@Al₂O₃ catalyst obviously allowed the highest yield of 1,5-PeD (97%) with a productivity of 3.67 mmol 1,5-PeD per g_cat.per min from FFalc in water at 140 °C and 10 bar H₂, after 3 h. The presence of Ru₃Sn₇ or Ru–SnO_x catalysed the partial hydrogenation of the furan ring of FFalc to form 4,5-dihydrofuranmethanol (4,5-DHFM), and the acidic species of SnO_x or Snⁿ⁺ or acidic Al₂O₃ were used for activating C2–O for ring opening processes, while Ru⁰ was used for the subsequent hydrogenation process, leading to high yield of the final 1,5-PeD product. This is the highest reported yield of 1,5-PeD from one-pot hydrogenolysis of FFalc under mild conditions. Catalytic performance of the recycled (op)Ru–(1.30)Sn@Al₂O₃ catalyst was restored after reactivation with H₂ at 400 °C for 1 h.