title: Steric effect of substituents on the extraction of lanthanoids(III) with N-p-(n-, iso- and tert-)butylbenzoyl-N-phenylhydroxylamine.
abstract: N-p-(n-, iso- and tert-)Butylbenzoyl-N-phenylhydroxylamine (HL) was synthesized to evaluate the steric effect of the substituent on the mutual extraction separation of representative lanthanoids(III) (Ln). Lanthanoids(III) were all found to be extracted with compounds as self-adducts of the form LnL(3)(HL)(2). It was found that the structure of the substituents in N-p-butylbenzoyl-substituted N-phenylhydroxylamine is closely related to the separation factor for the pair of Yb/Eu. The separation factors for a pair of Eu/Yb with these compounds decreased in the order of tert-butyl derivative>iso->n-, with a decreasing Taft's E(s) value, that is, with an increasing steric effect of the substituent group. The correlation between the separation factor and the stereochemical shape of the substituent was also investigated.
authors.affiliation: Department of Material Science, Kitami Institute of Technology, Kitami 090, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Inoue
authors.forename: Q
authors.initials: Q
authors.lastname: Zhang
authors.forename: M
authors.initials: M
authors.lastname: Uto