Complex formation and liquid–liquid extraction of anionic chelate of cobalt(II)-4-(2-thiazolylazo)resorcinol with 1,4-diphenyl-3-(phenylamino)-1H-1,2,4-triazole

The complex formation of anionic chelate of Co(II)–4-(2-thiazolylazo)resorcinol (TAR) with 1,4-diphenyl-3-(phenylamino)-1H-1,2,4-triazole (Nitron, Nt) in the liquid–liquid extraction system Co(II)–TAR–Nt–H2O–CHCl3 was studied. The optimum conditions for the formation of ternary ion-association complex Co–TAR–Nt were determined. The molar ratio of the reagents was determined by independent methods. Based on it, reaction scheme and general formula of the complex was suggested. The extraction equilibriums were investigated and quantitatively were characterized by the equilibrium constants and recovery factor with the aid of independent methods. The effect of various foreign ions and reagents on the complex formation between the anionic chelate Co(II)-TAR and the nitronium cation was studied. The validity of beer’s law was checked and some analytical characteristics were calculated.