Spectrophotometric Studies on the Vanadium(V)-Chelates with N-Arylhydroxamic Acids. A Superior Method for the Extraction and Spectrophotometric Determination of Vanadium in Steels

The reaction of 18 N-arylhydroxamic acids ·with V{V) in different acidities and under varying experimental conditions have been investigated. In concentrated HCl an intensely violet chelate of V(V), which is readily extracted into chloroform, is formed. The substitution in the hydroxamic acid functional grouping affects the hue and spectral characteristics of the V(V)-chelates. It is inferred that N-p-Cl-phenyl-p-methoxybenzohydroxamic acid retains all the useful features of N-phenylbenzohydroxamic acid as a reagent for V(V) but surpasses it in sensitivity and selectivity of the reaction. With this quick method vanadium has been determined in analysed steels without the recourse of masking agents or prior separations. The excellent results obtained on these samples are taken as a proof of the reliability, precision and accuracy of the method