Analysis of nickel by solid-liquid separation after liquid-liquid extraction. -Spectrophotometric determination of nickel after extraction of its nioxime complex with molten naphthalene-

摘要

Nioxime reacts with nickel to form a water-insoluble red complex.This complex is quantitatively extracted into molten naphthalene attemperature above 81 ℃. The solidified mixture of the complex andnaphthalene is dissolved in chloroform at 50 - 60 ℃, and the smallamounts of nickel in the solution are determined spectrophotometrically.The factors such as pH, amounts of nioxime and naphthalene are studied,and the molar absorptivity, sensitivity and relative standard deviationare evaluated. The extracted complex is stable in both naphthaleneand naphthalene-chloroform solution. The extraction of this complexinto molten naphthalene is rapidly completed by contact with moltennaphthalene or by slight shaking. This complex is mostly insoluble inchloroform, benzene, etc., but soluble in molten naphthalene. Themixture of the complex and naphthalene is insoluble in dimethylformamide,dimethylsulfoxide, acetonitrile, dioxane, isoamylacetate, chlorobenzene,etc., at 50 - 60 ℃.