水相中有机化学品和卤素自由基反应速率常数的定量结构-活性关系模型

A quantitative structure-activity relationship model for reaction rate constants of organic chemicals with halogen radicals in aqueous phase

卤素自由基尤其是氯自由基在污水中难降解污染物的降解以及表层海水中环境微污染物的降解过程中发挥重要作用,能够影响污染物的环境持久性与毒性风险。在污水及表层海水中存在着多种多样的有机污染物,单纯依靠实验手段测定它们和氯自由基的反应速率常数费时费力并且成本较高。因此本研究通过发展氯自由基与有机污染物的反应速率常数的QSAR模型来实现反应速率常数的定量预测。本研究搜集了28种有机化合物与Cl^(·)的反应速率常数以及18种有机化合物与Cl_(2)^(·−)的反应速率常数的实测值,采用多元线性回归(MLR)分别建立了QSAR模型。lgk_(Cl⋅)=11.133−7.236×Dv−0.087×VE3sign_RG+0.569×GATS5e−0.158×H-051。lgk_(Cl⋅)的QSAR模型的校正决定系数(R^(2)_(adj,tr))为0.810,均方根误差(RMSE_(train))为0.34,去一法交叉验证系数(Q^(2)_(LOO))为0.716,外部验证系数Q^(2)_(ext)=0.793;lgkC_(l2⋅)-=3.657+0.374×RDF010s−0.037×ATSC5s+0.073×L/Bw。lgkC_(l2⋅)-QSAR模型R^(2)_(adj,tr)为0.902,RMSE_(train)为0.29,Q^(2)_(LOO)为0.839,Q^(2)_(ext)为0.629。表明两个模型具有较高的拟合优度、稳健性和预测能力。应用域表征结果显示所选择的模型具有较好的代表性,所有化合物均在应用域范围内。所构建的模型可以实现含羟基,羰基,羧基等多种官能团有机化合物k_(Cl⋅)及kC_(l2⋅-)的定量预测。

Halogen radicals,especially chlorine radicals,play an important role in the transformation and degradation of micro-pollutants in sewage and surface seawater,which can affect the persistence and toxicity risk of pollutants in water environment.There are many kinds of organic pollutants in aqueous phase.However,it is time-consuming and costly to determine the reaction rate constants of organic pollutants with chlorine radicals based on the experiments.Quantitative structure-activity relationship(QSAR)is well recognized as a valuable tool to achieve rapidly quantitative prediction of these reaction rate constants.In this study,the reaction rate constants of 28 organic compounds with Cl^(·)and 18 organic compounds with Cl_(2)^(·−)were collected.QSAR models were then established by multiple linear regression(MLR)for these compounds,respectively(i.e.lgk_(Cl⋅)=11.133−7.236 Dv−0.087 VE3sign_RG+0.569 GATS5e−0.158 H-051 and lgk_(Cl2⋅-)=3.657+0.374 RDF010s−0.037 ATSC5s+0.073 L/Bw).It shows that these two models have good fit,robustness and strong prediction ability,with the adjusted determination coefficients(R^(2)_(adj,tr))of 0.810 and 0.902,the root-mean-square errors(RMSE_(train))of 0.34 and 0.29,leave-one-out cross validated coefficients(Q^(2)_(LOO))of 0.716 and 0.839,and the external validation coefficients(Q^(2)_(ext))of 0.793 and 0.629,respectively.The applicability domain of the two models reveals that the developed models have better representation,and all of compounds are in the applicability domain.The models constructed in this paper can be used in the quantitative prediction of k_(Cl⋅)andk_(Cl2⋅-)reaction rate constants for many types of organic chemicals,such as compounds with functional groups of hydroxyl,carbonyl and carboxyl.