Highly chemoselective hydrogenation of lactone to diol over efficient copper-based bifunctional nanocatalysts

Abstract

Owing to the high economic values and broad applications of diols with various alkyl chains, the development of efficient heterogeneous catalysts for the highly chemoselective synthesis of diols is highly desirable. In this work, a range of bifunctional Cux/Mg3-xAlO (x = 0.5, 1, 1.5, 2) nanocatalysts derived from layered double hydroxides (LDHs) precursors were fabricated and evaluated in the selective hydrogenation of lactones to synthesize diols. Systematic structure characterizations indicated the bifunctional catalytic sites containing active Cu nanoparticles with controllable sizes and tunable base sites could be finely constructed in the Cux/Mg3-xAlO catalysts. Intrinsic catalytic activity tests were conducted to reveal the structure-activity relationship in the model reaction of selective hydrogenation of γ-valerolactone (GVL) to produce 1,4-pentanediol (1,4-PeD); it was found that the optimal bifunctional Cu1.5/Mg1.5AlO catalyst exhibited greatly improved catalytic activity and selectivity for this reaction, which surpassed various copper-based reference catalysts; the excellent catalytic performance of Cu1.5/Mg1.5AlO was mainly attributed to the cooperative effect of the well-dispersed active Cu nanoparticles and the appropriate surface base sites nearby. Moreover, the bifunctional Cu1.5/Mg1.5AlO catalyst could be extended to other lactones with different ring sizes. This work provides a low-cost, environmentally benign and atom-economic heterogeneous catalytic system for the highly selective and sustainable synthesis of value-added diols.