Microdetermination of Some Antipyrines with Iodine PDF

Keywords

chemistry, hydrochloric acid, oxidation

Abstract

A new simple, accurate, and sensitive titrimetric method has been developed for the determination of antipyrine, 4-aminoantipyrine and dipyrone. The method is based on the oxidation of the entitled compounds with an excess of a chloroform solution of iodine, removal of its excess and determination of the resulting iodide by the "so-called" Leipert procedure after 6-fold amplification. Antipyrine and 4-aminoantipyrine undergo quantitative oxidation in a media ranging from 0.1 M hydrochloric acid to 0.1 M sodium acetate solution with a consumption of 2 and 3 moles of iodine per mole of antipyrine and 4-aminoantipyrine, respectively. However, dipyrone consumes 3 moles of iodine in 0.1 M hydrochloric acid solution. The present method enables analysis of amounts as low as 30.10 and 20 micrograms of antipyrine, 4-aminoantipyrine and dipyrone, respectively. The recoveries ranging from 98.1-102.2%, and standard deviation from 0.1-1.6%, depending on the concentration level.