As primary degradation products of phthalate esters,phthalate monoesters(MPEs)have been widely detected in various aquatic environments and drawn growing toxicological concerns.Hydrolysis kinetics that is of importanc...As primary degradation products of phthalate esters,phthalate monoesters(MPEs)have been widely detected in various aquatic environments and drawn growing toxicological concerns.Hydrolysis kinetics that is of importance for assessing environmental persistence of chemicals remain elusive for MPEs.Herein,kinetics of base-catalyzed and neutral hydrolysis for 18 MPEs with different leaving groups was investigated by density functional theory calculation.Results indicate that MPEs with leaving groups having p Kaof<10 prefer dissociative transition states.MPEs are more persistent than their parents,and their hydrolysis half-lives were calculated to vary from 3.4 min to 79.2 years(p H=7–9).A quantitative structure-activity relationship model was developed for predicting the hydrolysis kinetics parameters.It was found that p Kaof the leaving groups and electronegativity of the MPEs are key factors determining the hydrolysis kinetics.This work may lay a theoretical foundation for better understanding the chemical process that governs MPE persistence in aquatic environments.展开更多
Predicting the logarithm of hexadecane/air partition coefficient(L)for organic compounds is crucial for understanding the environmental behavior and fate of organic compounds and developing prediction models with poly...Predicting the logarithm of hexadecane/air partition coefficient(L)for organic compounds is crucial for understanding the environmental behavior and fate of organic compounds and developing prediction models with polyparameter linear free energy relationships.Herein,two quantitative structure activity relationship(QSAR)models were developed with 1272 L values for the organic compounds by using multiple linear regression(MLR)and support vector machine(SVM)algorithms.On the basis of the OECD principles,the goodness of fit,robustness and predictive ability for the developed models were evaluated.The SVM model was first developed,and the predictive capability for the SVM model is slightly better than that for the MLR model.The applicability domain(AD)of these two models has been extended to include more kinds of emerging pollutants,i.e.,oraganosilicon compounds.The developed QSAR models can be used for predicting L values of various organic compounds.The van derWaals interactions between the organic compound and the hexadecane have a significant effect on the L value of the compound.These in silico models developed in current study can provide an alternative to experimental method for high-throughput obtaining L values of organic compounds.展开更多
基金supported by the National Natural Science Foundation of China (No.22136001)the National Key R&D Program of China (No.2022YFC3902100)+2 种基金the Key R&D Program of Hebei Province (No.21374001D)the Supercomputing Center of Dalian University of Technologythe National Supercomputer Center in Tianjin。
文摘As primary degradation products of phthalate esters,phthalate monoesters(MPEs)have been widely detected in various aquatic environments and drawn growing toxicological concerns.Hydrolysis kinetics that is of importance for assessing environmental persistence of chemicals remain elusive for MPEs.Herein,kinetics of base-catalyzed and neutral hydrolysis for 18 MPEs with different leaving groups was investigated by density functional theory calculation.Results indicate that MPEs with leaving groups having p Kaof<10 prefer dissociative transition states.MPEs are more persistent than their parents,and their hydrolysis half-lives were calculated to vary from 3.4 min to 79.2 years(p H=7–9).A quantitative structure-activity relationship model was developed for predicting the hydrolysis kinetics parameters.It was found that p Kaof the leaving groups and electronegativity of the MPEs are key factors determining the hydrolysis kinetics.This work may lay a theoretical foundation for better understanding the chemical process that governs MPE persistence in aquatic environments.
基金supported by the National Natural Science Foundation of China (No.21936005)
文摘Predicting the logarithm of hexadecane/air partition coefficient(L)for organic compounds is crucial for understanding the environmental behavior and fate of organic compounds and developing prediction models with polyparameter linear free energy relationships.Herein,two quantitative structure activity relationship(QSAR)models were developed with 1272 L values for the organic compounds by using multiple linear regression(MLR)and support vector machine(SVM)algorithms.On the basis of the OECD principles,the goodness of fit,robustness and predictive ability for the developed models were evaluated.The SVM model was first developed,and the predictive capability for the SVM model is slightly better than that for the MLR model.The applicability domain(AD)of these two models has been extended to include more kinds of emerging pollutants,i.e.,oraganosilicon compounds.The developed QSAR models can be used for predicting L values of various organic compounds.The van derWaals interactions between the organic compound and the hexadecane have a significant effect on the L value of the compound.These in silico models developed in current study can provide an alternative to experimental method for high-throughput obtaining L values of organic compounds.
