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

Abstract

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). Herein, 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 reported procedures (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.