The stability and solubility of cadmium(II)-8-oxyquinoline complexes in water and micellar solutions of sodium dodecyl sulfate

The formation of cadmium 8-oxyquinoline (HOx) complexes in water and a 0.01 M aqueous solution of sodium dodecyl sulfate (293 K, 0.01) was studied by pH-metric titration. Mathematical simulation of the most probable equilibria gave complex formation constants logβ₁ = 6.17 ± 0.32 (CdOx⁺) and logβ₂ = 14.60 ± 0.14 (CdOx₂) in aqueous solution and apparent stability constants logβ₁ = 8.64 (CdOx⁺) and logβ₂ = 17.59 (CdOx₂) in a solution of dodecyl sulfate. The solubility of cadmium dioxyquinolate in water at pH from 3 to 6 and a micellar sodium dodecyl sulfate medium was determined by the method of saturated solutions. The solubility product pL _p = 21.3 ± 0.9 (H₂O, 293 K) was calculated by modeling the solution of CdOx₂ with taking into account all acid-base interactions and complex formation reactions.