EQUILIBRIUM ASPECTS OF THE EXTRACTION OF CESIUM NITRATE BY DICYCLOHEXANO-21-CROWN-7, DIBENZO-21-CROWN-7 AND BIS-[TERT-ALKYLBENZO]-21-CROWN-7 IN 1,2-DICHLOROETHANE
Yp. Deng et al., EQUILIBRIUM ASPECTS OF THE EXTRACTION OF CESIUM NITRATE BY DICYCLOHEXANO-21-CROWN-7, DIBENZO-21-CROWN-7 AND BIS-[TERT-ALKYLBENZO]-21-CROWN-7 IN 1,2-DICHLOROETHANE, Journal of the Chemical Society. Faraday transactions, 91(23), 1995, pp. 4215-4222
Citations number
55
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
The extraction of caesium nitrate has been measured for the crown ethe
rs dibenzo-21-crown-7 (DB21C7), bis-[4(5),4'(5')-tert-butylbenzo]-21-c
rown-7 [B(tBB)21C7], bis-[4,4'-tert-octylbenzo]-21-crown-7 [B(tOB)21C7
] and dicyclohexano-21-crown-7 (DC21C7) in 1,2-dichloroethane at 25 de
grees C. Variation of the aqueous caesium nitrate concentration up to
0.4 mol dm(-3) and organic-phase crown ether concentration up to 0.025
mol dm(-3) was modelled by the program SXLSQI. Formation of the speci
es CsBNO3 (B = crown ether) and partial dissociation to the ions CsBand NO3- in the organic phase satisfactorily account for the observed
behaviour of the benzo crown ethers. However, evidence for both 1:1 an
d 1:2 metal:crown complexes was obtained for DC21C7. Differences in al
kylation of the benzo groups did not produce substantial differences i
n the extraction behaviour of the three benzo crowns. By contrast, DC2
1C7 extracts CsNO3 much more strongly than the benzo crowns. Extractio
n constants are compared with constants available from previous studie
s of caesium extraction by related polyoxyethylene compounds.