Biomass-derived furans offer sustainable routes to adipic acid (AA), a key chemical in Nylon-6,6 synthesis. In this work, we show that tetrahydrofuran-2,5-dicarboxylic acid (THFDCA) is a viable precursor for AA production, achieving up to 89% yield in a metal-free system containing HI and molecular H₂ in a propionic acid solvent at 160 °C. Reactivity studies demonstrate that the interplay between HI, H₂, and the solvent is essential for effective THFDCA ring opening. By measuring the reaction orders of HI and molecular H₂ and calculating an acid–base equilibrium constant in a nonaqueous solvent, we show that HI plays a multifaceted role in the reaction by acting both as a proton source and an iodide source to selectively cleave C–O bonds without overhydrogenation of carboxylic acid groups. Using reactivity studies, kinetic measurements, and first-principles computational insights, we demonstrate that metal-free activation of molecular H₂ plays a key role in the reaction, following HI-mediated cleavage of the etheric C–O bond in THFDCA.

中文翻译：

---

通过生物量衍生的四氢呋喃-2,5-二羧酸的无金属选择性氢解生产己二酸

生物质衍生的呋喃为尼龙6,6合成中的关键化学品己二酸（AA）提供了可持续的途径。在这项工作中，我们表明四氢呋喃-2,5-二羧酸（THFDCA）是用于AA生产的可行前体，在丙酸溶剂中，在HI和分子H ₂的无金属体系中，在90℃时，可获得高达89％的收率。 160℃。反应性研究表明，HI，H ₂和溶剂之间的相互作用对于有效的THFDCA开环至关重要。通过测量HI和分子H ₂的反应阶数并计算非水溶剂中的酸碱平衡常数，我们表明HI在反应中起着多方面的作用，既充当质子源又充当碘化物源，以选择性地裂解C-O键而不会使羧酸基团过度加氢。使用反应性研究，动力学测量和第一性原理计算见解，我们证明了在HI-介导的THFDCA中醚键C-O裂解之后，分子H ₂的无金属活化在反应中起着关键作用。