Single-Step Hydrogenolysis of Furfuryl Alcohol to 1,2-Pentanediol by CoWO4 Catalyst

Furfuryl alcohol (FOL) is a biomass derivative used in polymer and fine chemical industries. Hydrogenation of FOL was reported to give tetrahydrofurfuryl alcohol (THFA), while its hydrogenolysis gave 1,2-pentanediol (1,2-PeD) and 1,5-pentanediol (1,5-PeD) in pressurized hydrogen by platinum group metals (e.g., Ru, Pd, and Pt). Here, cobalt tungstate (CoWO4) catalyzed selective hydrogenation or hydrogenolysis of FOL to give THFA or 1,2-PeD in the absence of pressurized hydrogen. Crystalline CoWO4 was synthesized hydrothermally at a relatively lower temperature (<160 °C) and shorter time (<10 h) compared to the reported procedure (180–200 °C, 15–24 h). Lower hydrothermal temperature (<150 °C) yields low-crystalline CoWO4. Catalytic differences of CoWO4 in crystalline and low-crystalline phases were observed in hydrogenolysis of FOL in alcohols. We found that 1,2-PeD of 67 % was selectively achieved in 2-propanol at 160 °C for 7 h by low-crystalline CoWO4 (5 mol%), while the same reaction in ethanol gave 54 % THFA. The reaction was proposed to be a pseudo first-order towards FOL with the experimental energy barrier of 107 kJ/mol and turnover frequency (TOF) up to 3.6 h−1.