基于QSAR对偶氮染料光响应性及降解路径研究

Study on the photoresponse and degradation path of azo dyes based on QSAR

采用密度泛函理论方法计算偶氮染料类化合物的量子化学参数,研究该类化合物结构与光响应活性的定量构效关系(QSAR),应用多元回归方法建立的方程具有显著统计学意义,并结合紫外光谱结果进行降解过程预测。结果表明:光催化体系中会最先造成偶氮染料的N=N键与萘环的断开,然后再生成其他副产物,副产物再经过电子转移、开环等一系列反应,生成苯环与羧酸类物质等小分子物质,最后被矿化为CO_(2)和H_(2)O。偶氮染料分子结构中苯环或萘环所连接的官能团会优先于苯环本身被降解,其结构对光催化脱色性能影响大小的顺序为:分子中的碳原子数>偶氮键数目>磺酸基数目。而染料分子描述符中影响HLG的顺序为:(MW/S)>(I/O)>n(AR)>n(N=N)。

The density functional theory method is used to calculate the quantum chemical parameters of azo dyes,and the quantitative structure-activity relationship(QSAR)of the structure and photoresponse activity of the compounds is studied.The equations established by the multiple regression method have significant statistical significance,and combining the results of the UV spectrum to predict the degradation process.The results show that the photocatalytic system will first cause the N=N bond of the azo dye to be disconnected from the naphthalene ring,and then generate other by-products.The by-products undergo a series of reactions such as electron transfer and ring opening to form a benzene ring.With small molecules such as carboxylic acids,they are finally mineralized into CO_(2) and H_(2)O.The functional group connected to the benzene ring or naphthalene ring in the molecular structure of the azo dye is preferentially degraded over the benzene ring itself.The order of the effect of the structure on the photocatalytic decolorization performance is the number of carbon atoms in the molecule>the number of nitrogen and nitrogen bonds>the number of sulfonic groups.The sequence that affects HLG in the dye molecule descriptor is( MW/S)>(I/O) > n (AR)> n (N=N).