Extraction-Spectrophotometric Determination of Higher Carboxylic Acids With Bis[2-(5-Chloro-2-Pyridylazo)-5-Diethylaminophenol] Cobalt(iii) Chloride

Abstract

Higher carboxylic acid reacts with Bis[2-(5-chloro-2-pyridylazo)-5-diethylaminophenol] cobalt(III) chloride, Co-5-Cl-PADAP, to form a 1:1 ion-pair, which is extracted into chlorobenzene in a single extraction at pH 11. The molar absorptivities of the ion-pairs of C12, C14, C16 and C18 acids are 3.5, 6.6, 7.6 and 7.6×104 1 mol−1 cm−1 at 563 nm, respectively.