Chiral perspective evaluations: Enantioselective hydrolysis of 6PPD and 6PPD-quinone in water and enantioselective toxicity to Gobiocypris rarus and Oncorhynchus mykiss

作者：Shanshan Di, Zhenzhen Liu, Huiyu Zhao, Ying Li, Peipei Qi, Zhiwei Wang, X. Q. Hao, Yuanxiang Jin, Xinquan Wang · 发表于：Environment International · 年份：2022 · DOI：10.1016/j.envint.2022.107374 · 被引用次数：165 · 研究领域：Pharmaceutical and Antibiotic Environmental Impacts、Environmental Toxicology and Ecotoxicology、Antibiotics Pharmacokinetics and Efficacy

As a ubiquitous tire antidegradant, N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD) is persistently released into the environment. It is highly toxic to aquatic organisms, and its transformation product 6PPD-quinone (6PPD-Q), is “very highly toxic” to Oncorhynchus kisutch at a median lethal concentration (LC50) of < 0.1 ng/mL. Notably, 6PPD and 6PPD-Q are chiral compounds. Here, enantioselective evaluations, including hydrolysis and acute toxicity were conducted after preparing the enantiomer, confirming the enantiomer absolute configuration and establishing enantioseparation methods. In the 6PPD hydrolysis experiments, the products 6PPD-Q, phenol, 4-[(1,3-dimethylbutyl)amino]- (4-DBAP) and 4-hydroxydiphenylamine (4-HDPA) were detected. In different water solutions, the hydrolysis of 4-DBAP and 4-HDPA was very fast (0.87–107 h), while the 6PPD-Q hydrolysis half-lives (12.8–16.3 d) were significantly longer than 6PPD (4.83–64.1 h). At the enantiomeric level, no enantioselective hydrolysis and conversion occurred. R-6PPD generated R-6PPD-Q, and S-6PPD generated S-6PPD-Q, and the formation rate of S-6PPD-Q was 1.77 times faster than R-6PPD-Q. In terms of the enantioselective toxicity, the 6PPD enantiomer was highly toxic to China-specific Gobiocypris rarus (LC50, 162–201 ng/mL), and it had no enantioselective difference. 6PPD-Q was “very highly toxic” (LC50, 1.66–4.31 ng/mL) to Oncorhynchus mykiss, which is of commercial importance, and the toxicities of rac-6PPD-Q and...