A fundamental understanding of biomass-based transformation of furfural (1a) to 2-furamide (4a) is highly desirable for the extension of amide chemistry. In this research, direct amidation of 1a with hydroxylamine to 4a was investigated by using a Cu-doped Co₃O₄ (Cu/Co₃O₄) catalyst with 2-furancarboxaldehyde oxime (2a) and 2-furonitrile (3a) as detectable intermediates. Mechanism research has demonstrated the presence of two competitive, independent, and parallel reaction pathways: (i) direct 2a-to-4a rearrangement (the Williams mechanism), and (ii) 2a-to-3a dehydration followed by 3a-to-4a rehydration (the classic mechanism) with the rehydration as the rate-determining step. Subsequent kinetic analysis by “concentration–time” integrals revealed that the Williams mechanism was always the predominant reaction pathway, with the reaction rate constant being almost 22 times greater than that of the classic mechanism. The catalytic performance of Cu/Co₃O₄ was correlated to its surface concentration of oxygen vacancy and surface acidity. The insights thus highlight a kinetic understanding of a complex consecutive/parallel transformation of biomass-based aldehyde for amide product.

中文翻译：

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使用“浓度-时间”积分对糠醛连续/平行转化为生物质基伯酰胺的动力学分析

对基于生物质的糠醛 ( 1a ) 转化为 2-呋喃酰胺 ( 4a ) 的基本理解对于酰胺化学的扩展非常重要。在这项研究中，通过使用 Cu 掺杂的 Co ₃ O ₄ (Cu/Co ₃ O ₄ ) 催化剂，以 2-呋喃甲醛肟 ( 2a ) 和 2-呋喃腈 ( 3a ) 作为可检测的，研究了1a与羟胺直接酰胺化为4a中间体。机制研究表明存在两种竞争性、独立且平行的反应途径：(i) 直接2a -to- 4a重排（威廉姆斯机制），以及 (ii) 2a到3a脱水，然后3a到4a再水化（经典机制），再水化作为决速步骤。随后通过“浓度-时间”积分进行的动力学分析表明，威廉姆斯机制始终是主要的反应途径，反应速率常数几乎是经典机制的 22 倍。_{Cu/Co 3} O ₄的催化性能与其表面氧空位浓度和表面酸度有关。因此，这些见解突出了对基于生物质的醛对酰胺产品的复杂连续/平行转化的动力学理解。