In this study, a series of CuCoAl catalysts with different Cu/Co molar ratios were prepared from hydrotalcite-like precursors and then adopted for -valerolactone (GVL) hydrogenation to 1,4-pentanediol (1,4-PeD). By tuning the Cu/Co ratio in the CuCoAl catalysts and optimizing the reaction conditions, nearly 100% yield of 1,4-PeD was finally achieved with the CuCoAl catalyst (Cu/Co = 1: 4) at 433 K and 4 MPa H. The high activity of the CuCoAl catalyst was attributed to the existence of Cu-CoO synergistic active sites and the abundant surface acidity. The electron transfer from Cu to Co resulted in the formation oxygen-defected CoO sites and surface acidic sites, which were beneficial for the adsorption of GVL and the activation of C-O/C=O bonds. The proximity between Cu particles and defective CoO facilitated the dissociative adsorption of H on Cu and the subsequent hydrogen spillover to CoO sites, thereby significantly promoted the selective hydrogenation of GVL to 1,4-PeD. In addition, applications of the CuCoAl catalyst to the ring-opening reactions of other lactones (including α-adamyllactone, γ-caprolactone, δ-pentyllactone, and ε-caprolactone) were further investigated. Eventually, high yields (> 93%) of the corresponding diols were attained, demonstrating the excellent catalytic versatility of CuCoAl in selective hydrogenation of lactones. Overall, this work shows high potential of hydrotalcite-derived CuCoAl catalysts for selective hydrogenation of GVL to 1,4-PeD, and provides insights for the design of efficient bimetallic catalysts in lactone hydrogenolysis.

中文翻译：

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水滑石 CuCoAl 催化剂上 γ-戊内酯选择性加氢生成 1,4-戊二醇

本研究以类水滑石前驱体为原料制备了一系列不同Cu/Co摩尔比的CuCoAl催化剂，然后用于β-戊内酯（GVL）加氢生成1,4-戊二醇（1,4-PeD）。通过调整CuCoAl催化剂中的Cu/Co比例并优化反应条件，最终在433 K和4 MPa H下使用CuCoAl催化剂（Cu/Co = 1: 4）实现了接近100%的1,4-PeD产率CuCoAl催化剂的高活性归因于Cu-CoO协同活性位点的存在和丰富的表面酸性。从Cu到Co的电子转移导致形成氧缺陷的CoO位点和表面酸性位点，这有利于GVL的吸附和CO/C=O键的活化。 Cu颗粒和缺陷CoO之间的接近促进了H在Cu上的解离吸附以及随后的氢溢出到CoO位点，从而显着促进了GVL选择性加氢为1,4-PeD。此外，还进一步研究了CuCoAl催化剂在其他内酯（包括α-金刚内酯、γ-己内酯、δ-戊内酯和ε-己内酯）开环反应中的应用。最终，获得了相应二醇的高收率（> 93%），证明了 CuCoAl 在内酯选择性加氢中优异的催化多功能性。总体而言，这项工作显示了水滑石衍生的 CuCoAl 催化剂用于 GVL 选择性加氢生成 1,4-PeD 的巨大潜力，并为内酯氢解中高效双金属催化剂的设计提供了见解。