Liquid crystal monomers (LCMs), widely used in liquid crystal displays, have been recognized as a class of potential emerging pollutants in the environment. However, their atmospheric fate and toxicity involved in the atmospheric transformation have been rarely investigated. Herein, we employed quantum chemical calculation and computational toxicology to systematically investigate the ^•OH-initiated oxidation kinetics and mechanism of three LCMs (4-cyanophenyl 4-ethylbenzoate (CEB), 4-cyano-3-fluorophenyl 4-ethylbenzoate (CEB-F), and 4-cyano-3,5-difluorophenyl 4-ethylbenzoate (CEB-2F)) in the atmosphere, and the toxicity of CEB-2F (as an example) during transformation. The calculated gaseous rate constants and half-lives for CEB, CEB-F, and CEB-2F at 298 K were in the range of (0.9–1.4) × 10^–12 cm³ molecule^–1 s^–1 and 5.7–8.9 days, respectively, suggesting that these LCMs had atmospheric persistence and long-range transport potential. The transformation products (TPs) of CEB-2F were found to be similar to those experimentally determined in ^•OH oxidation of particulate LCMs. Furthermore, some TPs were predicted to exhibit enhanced toxicity compared with the parent LCM, indicating that much attention should be also paid to their risks besides the original LCMs. These results would be helpful for the LCM regulation and provide guidance on their development and safe application.

中文翻译：

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典型液晶单体的大气命运和风险研究

广泛用于液晶显示器的液晶单体（LCM）已被公认为是环境中一类潜在的新兴污染物。但是，很少研究它们参与大气转化的大气命运和毒性。在本文中，我们采用了量子化学计算和计算毒理学系统地研究的^• OH引发氧化动力学和三个LCMS（4-氰基苯基4-乙基苯甲酸（CEB），4-氰基-3-氟苯基-4-乙基苯（CEB-F机构）和4-氰基3,5-二氟苯基4-乙基苯甲酸酯（CEB-2F）），以及转化过程中CEB-2F的毒性（例如）。CEB，CEB-F和CEB-2F在298 K时计算出的气体速率常数和半衰期在（0.9–1.4）×10 ^–12范围内cm ³分子分别为^–1 s ^–1和5.7–8.9天，表明这些LCM具有大气持久性和远距离迁移潜力。CEB-2F的转化产物（TPS）被认为是类似于在实验确定^•微粒的LCM的OH氧化。此外，预计某些TP会比亲本LCM表现出更高的毒性，这表明除原始LCM以外，还应引起更多的注意。这些结果将对LCM法规有所帮助，并为它们的发展和安全应用提供指导。