Quantitative Structure Property Relationships Study On Degradation Of Chlorophenols By USFe

In the article, At the same conditions, the degradation rate constants of 2-CP,2,4-DCP,2,4,5-TCP,2,4,6-TCP,2,3,4,6-TeCP and PCP were mensurated. The results show that the concentration of the reaction solution(C)/ the initial concentration of the reaction solution (C0) decreased exponentially with time, and the degradation follows pseudo-first-order reaction kinetics, that is dc/dt= -kt. The pseudo first-order degradation rate constants follow the decreasing order of PCP>2,3,4,6-TeCP>2,4,5- TCP>2,4-DCP>2,4,6-TCP>2-CP.At the optimized conditions, 25 quantum chemical descriptors were independent variables and the Logk was dependent variable. by regression analysis and partial least regression, the correlation between the logarithm value of degradation rate constant (Logk) and structure parameters was researched and quantitative structure–property relationship (QSPR) model was developed respectively. It can obtain the similar conclusion that logk was decided in the molecular bulk properties. logk increased with the increase of Q_Cl,Polar,Mr,Q_H⁺,CCR and EN₁, but adversely decreased with increase of E_lumo,FE,TEE,TE,Dipole and EE1.At the same conditions, by partial least regression (PSL), 14 quantum chemical descriptors were independent variables and the Logk was dependent variable. And QSPR model was developed credibly. This QSPR model shows that the descriptors vapor pressure (Vp), the highest occupied molecular orbital (E_homo), Log octanol water partition coefficient (LogKo/w) ,(E_lumo-E_homo)2and E_lumo-E_homo are the main factors in the degradation of chlorophenols by ultrasound combined with element iron; the value of k increases with the increase of E_homo and LogKo/w values, but adversely decreases with the increase of Vp, (E_lumo-E_homo)2 and E_lumo-E_homo values. Model also shows that, the degradation of chlorophenols (CPs) is not mainly in the cavitational bubble in the US/Fe system. The adsorption of Fe's surface is determinant step in the degradation of CPs and the oxidation of CPs is the dominant part.The path way of the degradation of CPs was studied both experiment and theory. The experiment results show that tetrachloro-1,2-benzoquinone,tatrachlorohydroquinone and 2,3,4,6-TeCP was detected during the degradation of PCP by US/Fe. The model results show that the breaking g of C-C have some influence on the degradation of CPs by US/Fe.