Crown-Ether Type Podands as Alkali Metal Cation Extractants: Influence of the Number of Oxygens in the Chain

• Type: Article in International Scientific Journal
• Date: 2010

Authors

Mário Valente (Author) FCUP; Sérgio Filipe Sousa (Author) FCUP; Alexandre Lopes Magalhães (Author) FCUP; Cristina Freire (Author) FCUP

Journal

Title: Journal of Solution Chemistry

Vol. 39 No. 8

Pages: 1230-1242

ISSN: 0095-9782

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 11 Citations

ISI Web of Science

Scopus - 11 Citations

Scientific classification

FOS: Engineering and technology > Chemical engineering

Other information

Authenticus ID: P-003-2HM

DOI: 10.1007/s10953-010-9579-9

Abstract (EN): Several polyether-type podands were synthesized that contained a variable number of potential donor oxygen atoms (four to twelve) and an aromatic ring in the chain. Extraction experiments were performed to elucidate the influence of the number of oxygen atoms on the extraction selectivity towards alkali metal picrates, from aqueous to dichloromethane phases. The results show that the extraction efficiency for lithium picrate is almost independent of the number of oxygen atoms in the podand. The extraction efficiency for sodium picrate was found to increase significantly with the number of oxygen atoms up to about seven, but for the potassium to cesium picrates the extraction efficiency increased up to about eight oxygen atoms. The increase in extraction efficiency may be rationalized in terms of the saturation of the cation's first coordination sphere: after a critical number of oxygen atoms is reached and the first coordination sphere is saturated, the much smaller detected increases in the extraction efficiency may be seen as a statistical effect. The discrimination between sodium and potassium pirates is only achieved when the podands possess seven or more oxygen atoms. Under the experimental conditions used, the podands studied are unable to discriminate between potassium, rubidium and cesium picrates.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13