Preparation of Monohydric Alcohols From Small-Molecule Diols Using Pd/C and Phosphotungstic Acid Bifunctional Catalysts

Monohydric alcohols are important platform molecules with diverse applications in organic synthesis, pharmaceuticals, food, and polymer industries. The production of monohydric alcohols via the selective hydrogenolysis of diols holds significant scientific and practical value. However, the precise catalytic control of the cleavage of target C–C and C–O bonds remains an open challenge, which often leads to low yields of the target products. Herein, metal-acid bifunctional catalysts were employed to boost the conversion of diols and improve the production of monohydric alcohols through hydrogenolysis. By regulating key reaction intermediates, a maximum yield of 76.2% for 1-propanol and a total monohydric alcohol yield of 84.9% were achieved within a short reaction time of 1 h. Our investigations demonstrate that the composite system of 5% Pd/C and phosphotungstic acid (HPW) catalyzes the conversion of ethylene glycol (EG) and 1,2-propanediol via a metal-acid synergistic effect, which enables the selective cleavage of C–C and C–O bonds. Ethylene glycol and 1,2-propanediol were thus converted to the monohydric alcohols (ethanol, n-propanol, and isopropanol) through hydrogenolysis and dehydration-hydrogenation processes. Additionally, the reaction order and activation energy barriers for the conversion of diols over the 5% Pd/C catalyst were determined experimentally. This work establishes a preliminary method for the production of monohydric alcohols from the hydrogenolysis of small-molecule diols by 5% Pd/C and HPW catalysts. Given the commercial availability of these catalysts, the developed catalytic system exhibits promising practical application potential and may facilitate the scale-up of this reaction. Graphical A 5% Pd/C–phosphotungstic acid (HPW) composite catalyzes the conversion of ethylene glycol and 1,2-propanediol via metal–acid synergy, enabling selective C–C/C–O cleavage. Hydrogenolysis and dehydration–hydrogenation yield ethanol, n-propanol, and isopropanol. Reaction orders and activation energies were determined, linking mechanistic insights to industrial scale-up for biomass diol upgrading.