Total hydrogenation of furfural (FAL) is an efficient way to produce the industrially important tetrahydrofurfuryl alcohol (THFOL). However, it is a challenge to obtain highly selective catalysts for this transformation especially under mild reaction conditions. Herein, we report that the β-ketoenamine-linked covalent organic framework (TpBD COF) supported ultrafine Pd nanoparticles exhibit significantly enhanced selectivity for THFOL compared to Pd/C (95% vs. 82 %) at almost full FAL conversion. This heightened selectivity is attributed to the increased electronic density on the Pd surface, resulting from the electron-donating effect of pendant groups in the TpBD COF. Moreover, kinetic investigations reveal that the activity of total FAL hydrogenation on Pd surface is linked to the rate-determining step in its first C = O hydrogenation process. Additionally, Pd/TpBD COF could catalyse various other bio-based furanic compounds to the corresponding furan ring saturated products in high yields. This work provides guidance for the rational design catalysts to improve its tandem hydrogenation efficiency.

中文翻译：

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温和条件下 Pd/COFs 上糠醛的全氢化

糠醛全氢化（FAL）是生产工业上重要的四氢糠醇（THFOL）的有效方法。然而，获得用于这种转化的高选择性催化剂是一个挑战，特别是在温和的反应条件下。在此，我们报告说，与 Pd/C 相比，β-酮烯胺连接的共价有机框架 (TpBD COF) 支持的超细 Pd 纳米粒子在几乎完全 FAL 转化的情况下表现出对 THFOL 的选择性显着增强（95% 与 82%）。这种选择性的提高归因于 Pd 表面电子密度的增加，这是由于 TpBD COF 中侧基的给电子效应所致。此外，动力学研究表明，Pd 表面上的总 FAL 氢化活性与其第一个 C = O 氢化过程中的速率决定步骤有关。此外，Pd/TpBD COF 可以高产率催化各种其他生物基呋喃化合物生成相应的呋喃环饱和产物。该工作为合理设计催化剂以提高串联加氢效率提供指导。