烃基黄药类捕收剂生物降解性能及其结构相关性研究

On the biodegradability and its correlation with its quantitative structure of the alkyl xanthates flotation collectors

选取最高占据轨道能量E（HOMO）、最低空轨道能量E（LUMO）分子体积Vm、分配系数ClgP、偶极距μ及二阶分子连接性指数2X作为烃基黄药类捕收剂的结构性参数,通过回归分析,建立了烃基黄药类捕收剂的定量结构-生物降解性能关系模型（QSBR）,并进行了预测。结果表明,E（LOMO）、2X（即分子最低空轨道能量水平和二阶分子连接性指数）对烃基黄药类捕收剂的生物降解性能有显著影响。

The article intends to make a study of the biodegradability and its correlation with its quantitative structure of the alkyl xanthates flotation collectors in hoping to learn to control and prevent the pollution of the agents as well as to provide a theory for the synthesis and application of the flotation agents.It is for the said purpose,we have chosen five kinds of alkyl xanthates flotation collectors as research goal with the method of shaking the cultivated solution of the aerobic biodegradability of ethyl xanthate,the isopropyl xanthate,n-butyl xanthate,isobutyl xanthate and the amyl xanthate.The experimental results we have gained show that the aerobic biodegradation of the tested compounds tends to follow the first-order kinetics and the rank order of the biodegradation rate constant from big to small,that is,the ethyl xanthate,n-butyl xanthate,the amyl xanthate,the isopropyl xanthate and the isobutyl xanthate.At the same time,with the decrease of the biodegradation degree of the alkyl xanthates,the DT-90 and half-life time tends to increase with the prolonging of the carbon chain and the number of alkyl lateral chains.Besides,through comparison,the branch degree has been found affected obviously by the degradability of alkyl xanthates.In addition,we have also analyzed and compared the relativity between the dynamic quantitative structure and the biodegradation of the alkyl xanthates,in hoping to deepen our study of the parameters of the chemical structure and the methods of the model development.What is more,we have also found such parameters as the greatest molecular orbital energy（E（HOMO））,and the lowest empty orbit energy（E（LUMO））,with its molecular volume（Vm）,the octanol-water partition coefficient（ClgP）,and the dipole moment（μ）.As to the second order molecular connectivity index ~2X is concerned,we have found that they are the ones of alkyl xanthates flotation collectors.Through the regression analysis,we have confirmed the correlation between the quantitative structure and the biodegradability on the alkyl xanthates flotation collectors,and found that the mathematical formula can be expressed in the equation below：kb=-4.2872-0.14734~2X-5.40155E（LUMO）.Thus,the biodegradability of alkyl xanthates flotation collectors can be found affected by E（LUMO） and ~2X quite obviously.Moreover,the regression equation can be said endowed with a high fitting degree,with its coefficient of correlation r being 0.997.