Abstract：
6PPD, a tire rubber antioxidant, poses substantial ecological risks because it can form a highly toxic quinone transformation product (TP), 6PPD-quinone (6PPDQ), during exposure to gas-phase ozone. Important data gaps exist regarding the structures, reaction mechanisms, and environmental occurrence of TPs from 6PPD ozonation. To address these data gaps, gas-phase ozonation of 6PPD was conducted over 24-168 h and ozonation TPs were characterized using high-resolution mass spectrometry. The probable structures were proposed for 23 TPs with 5 subsequently standard-verified. Consistent with prior findings, 6PPDQ (C18H22N2O2) was one of the major TPs in 6PPD ozonation (∼1 to 19% yield). Notably, 6PPDQ was not observed during ozonation of 6QDI (N-(1,3-dimethylbutyl)-N\'-phenyl-p-quinonediimine), indicating that 6PPDQ formation does not proceed through 6QDI or associated 6QDI TPs. Other major 6PPD TPs included multiple C18H22N2O and C18H22N2O2 isomers, with presumptive N-oxide, N,N\'-dioxide, and orthoquinone structures. Standard-verified TPs were quantified in roadway-impacted environmental samples, with total concentrations of 130 ± 3.2 μg/g in methanol extracts of tire tread wear particles (TWPs), 34 ± 4 μg/g-TWP in aqueous TWP leachates, 2700 ± 1500 ng/L in roadway runoff, and 1900 ± 1200 ng/L in roadway-impacted creeks. These data demonstrate that 6PPD TPs are likely an important and ubiquitous class of contaminants in roadway-impacted environments.
摘要：
6PPD,一种轮胎橡胶抗氧化剂，实质性的生态风险，因为它可以形成剧毒的醌转化产物（TP），6PPD-醌(6PPDQ),在暴露于气相臭氧期间。关于结构存在重要的数据差距，反应机制,6PPD臭氧氧化的TP和环境发生。为了解决这些数据差距，6PPD的气相臭氧化在24-168小时内进行，臭氧化TP使用高分辨率质谱进行表征。提出了23个TP的可能结构，随后进行了5个标准验证。与先前的发现一致，6PPDQ（C18H22N2O2）是6PPD臭氧化的主要TP之一（产率约1至19%）。值得注意的是,在6QDI（N-（1,3-二甲基丁基）-N'-苯基-对醌二亚胺）的臭氧化过程中未观察到6PPDQ，指示6PPDQ形成不通过6QDI或相关6QDITP进行。其他主要的6PPDTP包括多种C18H22N2O和C18H22N2O2异构体，假定的N-氧化物，N,N\'-二氧化物,和邻醌结构。在道路影响的环境样本中量化标准验证的TP，轮胎胎面磨损颗粒（TWP）的甲醇提取物中的总浓度为130±3.2μg/g，水性TWP渗滤液中的34±4μg/g-TWP，巷道径流2700±1500ng/L,和1900±1200纳克/升的道路影响小溪。这些数据表明，6PPDTP可能是道路影响环境中重要且普遍存在的一类污染物。
