酸性磷型萃取剂萃取稀土的线性自由能关系

Linear Free Energy Relationships in Extraction of Rare Earths by Acidic Organophosphorus Extractants

用线性回归分析探讨了各种类型和结构的一元酸性磷型萃取剂萃取稀土的表观萃取平衡常数 (lgKex)与萃取剂分子中取代基的电子效应参数 (ΣσΦ)和空间效应参数 (Συ )之间的相关关系。结果表明 ,对于这类萃取体系 ,线性自由能关系式lgKex=ρΣσΦ +ψΣυ+h 普遍成立。据此讨论了萃取剂结构与萃取性能之间的定量关系 ,可用于初步预测一定结构的这类萃取剂萃取稀土的lgKex值。

The correlation relationships of apparent extraction equilibrium constants(lg K ex ) with the electronic effect parameter(Σσ Φ ) and the steric effect parameter(Συ) of the substituents in extractant molecules were investigated by linear regression analysis in the extraction of rare earths by various classes and structures of monoacidic organophosphorus extractants. The results indicate that a linear free energy relationship formula lg K ex =ρΣσ Φ +ψΣυ+h generally follows for this kind of extraction systems. Accordingly, the quantitative structure behaviour relationships of extractants were discussed. These relationships can be preliminarily applied to predict the lg K ex values of rare earth extraction with definite strcutures of this class of extractants.