Ternary CuMgAl catalysts enable efficient one-pot cascade hydrogenation of levulinic acid to 1,4-pentanediol in water

Levulinic acid (LA), as a pivotal biomass platform compound, has attracted significant interest in the field of biorefining, particularly owing to its importance in the synthesis of the high value-added 1,4-pentanediol (1,4-PeD) via a two-step conversion, the hydrogenation of LA and dehydrative lactonization to the intermediate γ-valerolactone (GVL), and the subsequent ring-opening hydrogenolysis of GVL to 1,4-PeD. However, the ring-opening hydrogenolysis of GVL is kinetically restricted by a high reaction energy barrier. Therefore, the development of outstanding non-noble metal catalysts remains a significant challenge for the efficient conversion of GVL to 1,4-PeD. Herein, ternary CuMgAl catalysts were prepared via a coprecipitation method and applied to the one-pot cascade hydrogenation of LA to 1,4-PeD in water. Notably, a Cu 1 Mg 0.5 Al 1 catalyst achieved an impressive 1,4-PeD yield of 94.2% under mild conditions. The structure-performance relationship investigation on the Cu 1 Mg 0.5 Al 1 catalyst revealed a remarkable synergistic effect among Cu 0 sites, Cu + sites, oxygen vacancies and a well-balanced acid-base microenvironment. In particular, the medium-to-strong acidity derived from Cu + species and oxygen vacancies promotes GVL adsorption and subsequent ring-opening hydrogenolysis, while the basic sites effectively buffered the acidity to suppress the dehydrative side reaction of 1,4-PeD. Concurrently, adjacent highly dispersed Cu 0 sites supplied dissociated hydrogen atoms, a synergy that was crucial for achieving high 1,4-PeD yields. This work presents a feasible and sustainable route for producing 1,4-PeD from bio-based LA and offers valuable insights into the mechanism of GVL ring-opening hydrogenolysis.