Calixarene-hydroxamic acid

Extraction with triphenylarsine oxide in CHCI3 followed by the reaction with Arsenazo III (after stripping of the analytes with 4 M HCl) makes a basis of the determination of Zr and Hf (and Ti) in minerals and alloys [1], Sequential liquid-liquid extraction and spectrophotometric determination of zirconium(IV) with calixarene hydroxamic acid and thiocyanate has been described [2]. Colorimetric determination of Zr and Hf with Xylenol Orange and a liquid-liquid extraction of thenoyltrifluoroacetone complexes using H2O-IBMK has been studied [3]. 

A tetrameric calixarene with hydroxamic acid functional groups, supported on octadecyl-silica and XAD-4 resin Quantitative enrichment of Cu(II), Zn(II), and Mn(II) 110... 

The crown ether, 18-crown-6 [34—36], [2.2.2]-cryptand [37], and calixarene derivatives of hydroxamic acids have also been used for extraction of U(VI) [38]. 

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