Extraction of Gallium(III) with a New Azo Dye in The Presence or Absence of Xylometazoline Hydrochloride

Abstract

Complex formation between Ga(III) and 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR, H2L) was studied in a water-chloroform medium, in the presence or absence of xylometazoline hydrochloride (XMH). Optimum conditions for the extraction of Ga(III) were found. In the presence of XMH, the extracted ion-associate has the formula (XMH +)[Ga III L2], where HTAR is in its deprotonated form L 2-. Some key extractionspectrophotometric characteristics were determined: absorption maximum (521 nm), apparent molar absorptivity (5.8 × 10 4 dm 3 mol-1 cm-1), limit of detection (18 ng cm-3), limit of quantitation (60 ng cm-3), extraction constant (LogK = 4.44), distribution ratio (LogD = 2.2) and fraction extracted (99.3 %). In the absence of XMH, the extracted chelate contains one deprotonated and one monoprotonated HTAR: [Ga III (HL-)(L 2-)]. It has an absorption maximum at 523 nm and a shoulder at 580-590 nm. The pKa of HTAR (H2L ⇄ H + + HLequilibrium) was calculated (5.4) and the effect of foreign ions was studied.

Extractive Spectrophotometric Determination and Theoretical Investigations of Two New Vanadium(V) Complexes

“…Equations of complex formation and extraction, based on information for the state of V(V) [ 13 ] and HTAR (H 2 L) [ 47 , 48 ] at the optimum pH value, are as follows: 2 H 2 VO 4 − (aq) + 2 H 2 L (aq) + 2 TT + (aq) = [(TT + )[VO 2 (L)]] 2 (org) + 4 H 2 O H 2 VO 4 − (aq) + H 2 L (aq) + NTC + (aq) = (NTC + )[VO 2 (L)] (org) + 2 H 2 O …”

“…The obtained values, along with the values of distribution ratios (D) and fractions extracted (E), are given in Table 3. Equations of complex formation and extraction, based on information for the state of V(V) [13] and HTAR (H 2 L) [47,48] at the optimum pH value, are as follows:…”