<br>6：2 多氟烷基磷酸酯的电化学氧化——羟基自由基的转化途径和反应动力学模拟,Environmental Science & Technology

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6：2 多氟烷基磷酸酯的电化学氧化——羟基自由基的转化途径和反应动力学模拟
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2021-07-30 , DOI: 10.1021/acs.est.1c02106
Jonathan Zweigle ₁ , Boris Bugsel ₁ , Markus Schmitt ₁ , Christian Zwiener ₁

Affiliation

多氟烷基磷酸酯二酯（diPAP）广泛用于纸张和纸板浸渍，并通过生产过程和消费品的废物流排放。为了提高对 diPAPs 环境归宿的了解，使用电化学氧化（EO）来表征转化途径和反应动力学。将 6：2 diPAP 电化学转化为全氟羧酸（C₅–C₇ PFCA）和两种中间体（6：2 含氟调聚物羧酸 FTCA 和 6：2 含氟调聚物不饱和羧酸 FTUCA）。潜在中间体 6：2 monoPAP 和 6：2 含氟调聚物醇（FTOH）的 EO 显示出相似的转化产物，但比例不同。我们表明 6：2 diPAP 是由 OH 自由基（^•OH）反应引发的，探针分子对苯二甲酸测得的 ^•OH 稳态浓度、淬灭实验和反应的 pH 依赖性证明了这一点。PFHpA 是 6：2 diPAP 氧化的主要产物，它是在伪一级反应中形成的，其双分子速率常数估计为

= 9.4（±1.4） × 10⁷ M^–1 s^–1。这可用于估计 6：2 diPAP 与 ^•OH 反应的环境半衰期以及持久性 PFCA 的形成动力学。

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Electrochemical Oxidation of 6:2 Polyfluoroalkyl Phosphate Diester—Simulation of Transformation Pathways and Reaction Kinetics with Hydroxyl Radicals

Polyfluoroalkyl phosphate diesters (diPAPs) are widely used for paper and cardboard impregnation and discharged via waste streams from production processes and consumer products. To improve the knowledge about the environmental fate of diPAPs, electrochemical oxidation (EO) was used to characterize the transformation pathways and reaction kinetics. 6:2 diPAP was transformed electrochemically to perfluorocarboxylic acids (C₅–C₇ PFCAs) and two intermediates (6:2 fluorotelomer carboxylic acid, FTCA, and 6:2 fluorotelomer unsaturated carboxylic acid, FTUCA). EO of potential intermediates 6:2 monoPAP and 6:2 fluorotelomer alcohol (FTOH) showed similar transformation products but with different ratios. We show that 6:2 diPAP is initiated by OH radical (^•OH) reactions, as evidenced by the measured steady-state concentrations of ^•OH with the probe molecule terephthalic acid, quenching experiments, and pH dependency of the reaction. PFHpA was the main product of 6:2 diPAP oxidation, and it was formed in a pseudo-first-order reaction for which a bimolecular rate constant was estimated to be

= 9.4(±1.4) × 10⁷ M^–1 s^–1 by an initial rate approach. This can be utilized to estimate the environmental half-life of 6:2 diPAP for the reaction with ^•OH and the formation kinetics of persistent PFCAs.

更新日期：2021-08-17

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