美国西北大学William R. Dichtel和加州大学洛杉矶分校K. N. Houk小组近日取得一项新成果。经过不懈努力，他们开发了一种全氟代羧酸低温下矿化的方式。相关论文于2022年8月19日发表在《科学》杂志上。

全氟烷基化合物和多氟烷基化合物（PFAS）是在水资源中发现的对人类健康有害的持久性、生物累积性污染物。尽管目前的PFAS破坏策略主要用非选择性破坏机制，但研究者发现，全氟烷基羧酸（PFCAs）可以通过氢氧化钠介导的脱氟途径矿化。PFCA在极性非质子溶剂中脱羧生成活性全氟烷基离子中间体，在24 h内降解为氟离子（78 ~100%）。该反应的含碳中间体和产物与通常提出的单碳链缩短机制不一致，因此研究者转而通过计算化学发现了与各项实验结果一致的反应路线。

此外，研究者还观察到了含支链全氟烷基醚羧酸的降解，因此，一旦确定了激活它们极性头部基团的方式，这一反应也可以扩展到降解其他PFAS类。

附：英文原文

Title: Low-temperature mineralization of perfluorocarboxylic acids

Author: Brittany Trang, Yuli Li, Xiao-Song Xue, Mohamed Ateia, K. N. Houk, William R. Dichtel

Issue&Volume: 2022-08-19

Abstract: Per- and polyfluoroalkyl substances (PFAS) are persistent, bioaccumulative pollutants found in water resources at concentrations harmful to human health. Whereas current PFAS destruction strategies use nonselective destruction mechanisms, we found that perfluoroalkyl carboxylic acids (PFCAs) could be mineralized through a sodium hydroxide–mediated defluorination pathway. PFCA decarboxylation in polar aprotic solvents produced reactive perfluoroalkyl ion intermediates that degraded to fluoride ions (78 to ~100%) within 24 hours. The carbon-containing intermediates and products were inconsistent with oft-proposed one-carbon-chain shortening mechanisms, and we instead computationally identified pathways consistent with many experiments. Degradation was also observed for branched perfluoroalkyl ether carboxylic acids and might be extended to degrade other PFAS classes as methods to activate their polar headgroups are identified.

DOI: abm8868

Source: https://www.science.org/doi/10.1126/science.abm8868