TY - JOUR
T1 - Complexation of strontium in the synergistic extraction system dicyclohexano-18-crown-6, versatic acid, carbon tetrachloride
AU - Moyer, Bruce A.
AU - McDowell, W. J.
AU - Ontko, R. J.
AU - Bryan, S. A.
AU - Case, G. N.
PY - 1986/1/1
Y1 - 1986/1/1
N2 - The synergism in the extraction of Sr2+ from 0.5M Sr(NO3)2 by 0.05M dicyclohexano-18-crown-6 (DC18C6) + 0.1M Versatic 1519 (abbreviated V-acid or RCOOH, a neo carboxylic acid) in CCl4 has been found to stem from a strong 1:1 interaction between DC18C6 and Sr2+. However, both nitrate and carboxylate can function as the anion for the (DC18C6)Sr2+ moiety. At aqueous conditions corresponding to less than complete loading (i.e., [Sr2+)org < 0.05M for pH < 11.7), (DC18C6)Sr(NO3)2 precipitates as a solid. As the pH is raised in the interval 7 < pH < 11.7 to deprotonate the V-acid, the precipitate (DC18C6)Sr(NO3)2 becomes solubilized first with probable formation of a mixed-anion complex and finally with quantitative (0.05M) formation of the monomeric complex (DC18C6)Sr(OOCR)2·H2O at pH = 11.7 as confirmed by viscometric titration of 0.05M DC18C6 in wet CCl4 with Sr(OOCR)2, Karl-Fischer titrations, vapor-phase osmometry, and IR spectrophotometry.
AB - The synergism in the extraction of Sr2+ from 0.5M Sr(NO3)2 by 0.05M dicyclohexano-18-crown-6 (DC18C6) + 0.1M Versatic 1519 (abbreviated V-acid or RCOOH, a neo carboxylic acid) in CCl4 has been found to stem from a strong 1:1 interaction between DC18C6 and Sr2+. However, both nitrate and carboxylate can function as the anion for the (DC18C6)Sr2+ moiety. At aqueous conditions corresponding to less than complete loading (i.e., [Sr2+)org < 0.05M for pH < 11.7), (DC18C6)Sr(NO3)2 precipitates as a solid. As the pH is raised in the interval 7 < pH < 11.7 to deprotonate the V-acid, the precipitate (DC18C6)Sr(NO3)2 becomes solubilized first with probable formation of a mixed-anion complex and finally with quantitative (0.05M) formation of the monomeric complex (DC18C6)Sr(OOCR)2·H2O at pH = 11.7 as confirmed by viscometric titration of 0.05M DC18C6 in wet CCl4 with Sr(OOCR)2, Karl-Fischer titrations, vapor-phase osmometry, and IR spectrophotometry.
UR - http://www.scopus.com/inward/record.url?scp=84963147321&partnerID=8YFLogxK
U2 - 10.1080/07366298608917854
DO - 10.1080/07366298608917854
M3 - Article
AN - SCOPUS:84963147321
SN - 0736-6299
VL - 4
SP - 83
EP - 93
JO - Solvent Extraction and Ion Exchange
JF - Solvent Extraction and Ion Exchange
IS - 1
ER -