Predicting Partition Coefficients of Short-Chain Chlorinated Paraffin Congeners by Combining COSMO-RS and Fragment Contribution Model Approaches
Predicting Partition Coefficients of Short-Chain Chlorinated Paraffin Congeners by Combining COSMO-RS and Fragment Contribution Model Approaches
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结合 COSMO-RS 和片段贡献模型方法预测短链氯化石蜡同系物的分配系数
DOI：
10.26434/chemrxiv.12525656.v1
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
J. Hammer
中科院分区：
文献类型：
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作者：
S. Endo;J. Hammer
氯化石蜡（CPs）是具有不同链长和氯化模式的多氯正构烷烃的高度复杂混合物。关于个别同系物的物理化学特性的知识有限，但需要了解其环境归宿和潜在风险。这项工作结合了一个复杂的，但需要时间的量子化学为基础的方法COSMO-RS和快速运行的碎片贡献的方法来建立模型，预测分配系数的大量短链氯化石蜡（SCCP）同系物。对CP分子中长度达C4的分子片段进行计数，并将其用作解释变量，以开发用于预测COSMO-RS计算值的线性回归模型。由此产生的模型可以快速提供COSMO-RS对短链氯化石蜡同系物的辛醇-水分配系数（Kow）、空气-水分配系数（Kaw）和辛醇-空气分配系数（Koa）的预测，其均方根误差（RMSE）的准确度为0.1-0.3对数单位。模型预测的辛醇/水分配系数与单个结构异构体的实验值在1个对数单位内一致。计算了每种短链氯化石蜡同系物的分配系数范围，成功地再现了工业氯化石蜡混合物的实验辛醇/水分配系数范围。作为所开发方法的一个应用，绘制了预测的Kaw和Koa曲线，以评估每种短链氯化石蜡同系物的生物累积潜力。
Chlorinated paraffins (CPs) are highly complex mixtures of polychlorinated n-alkanes with differing chain lengths and chlorination patterns. Knowledge on physicochemical properties of individual congeners is limited but needed to understand their environmental fate and potential risks. This work combines a sophisticated but time-demanding quantum chemically based method COSMO-RS and a fast-running fragment contribution approach to establish models to predict partition coefficients of a large number of short-chain chlorinated paraffin (SCCP) congeners. Molecular fragments of a length of up to C4 in CP molecules were counted and used as explanatory variables to develop linear regression models for predicting COSMO-RS-calculated values. The resulting models can quickly provide COSMO-RS predictions for octanol–water (Kow), air–water (Kaw), and octanol–air (Koa) partition coefficients of SCCP congeners with an accuracy of 0.1–0.3 log units root mean squared errors (RMSE). The model predictions for Kow agree with experimental values for individual constitutional isomers within 1 log unit. The ranges of partition coefficients for each SCCP congener group were computed, which successfully reproduced experimental log Kow ranges of industrial CP mixtures. As an application of the developed approach, the predicted Kaw and Koa were plotted to evaluate the bioaccumulation potential of each SCCP congener group.