烃基结构对黄药捕收剂浮选性能的影响

采用密度泛函理论计算了一系列黄药捕收剂的几何构型和电子结构，利用最高占据分子轨道能量、自然布局分析电荷、电负性和绝对硬度等参数判断黄药捕收剂的浮选性能.研究结果表明：黄药阴离子是浮选溶液中的活性成分，键合原子为C—S单键中的S原子.最高占据分子轨道能量可较好地解释直链黄药（C₁-C₆）的浮选性能随碳链增长而增强的现象.在黄药同分异构体中，与极性基相连的碳原子上支链越多，烷基给电子诱导效应越强，该异构体的捕收活性越强.黄药同分异构体（C₃-C₅）的捕收活性顺序为：叔烃基黄药〉仲烃基黄药〉异烃基黄药.

Effect of alkyl structure on the flotation performance of xanthate collectors

The density functional theory(DFT) was applied to investigate the geometric and electronic properties of a series of xanthate collectors. The reactivity of xanthate collectors was analyzed by using the highest occupied molecular orbital(HOMO) energy,natural population analysis charge,electronegativity and hardness index. It is found that xanthate anions are the active ingredient in flotation solutions,and the bonding atom of a xanthate anion is the S atom in the C-S bond. The HOMO energy can be used to interpret that the flotation activity of straight chain xanthates(C₁-C₆) increases with the alkyl chain growth. The more the branched chains of carbon atoms attached to polar groups in xanthate isomers,the stronger the flotation activity is. The order of the flotation activity of C₃-C₅ xanthate isomers is as follows:tert-alkyl xanthate sec-alkyl xanthate iso-alkyl xanthate.