Spectrophotometric Study of the Ammonia – Pyridine – Pyrazolone Method
Abstract
This study consists of essentially two parts; Part I dealing with the mechanism of the ammonia-pyridine-pyrazolone reaction, and Part II dealing with the application of this reaction to the determination of nitrogen in steels and soils.The study of the mechanism of the reaction consisted of determining the effect of three variables: minimum con- centration of the reactants; dines; effect of substituted pyri- and the use of other compounds than pyrazolone, The study of the effect of minimum concentration of reactants showed very little as to the nature of the reaction, primarily due to interaction among the reactants themselves. The study of the effect of substituted pyridines showed clearly that -substitution hindered the reaction, while - and X-substitution caused little, if any, change. No compound containing a keto-group or two active hydrogen atoms, or both, was found that could be used in place of pyrazolone.The application of the ammonia-pyridine-pyrazolone reaction was extended to the determination of nitrogen insteels and soils. The method devised consisted essentially of converting the nitrogen present into ammonia and the subsequent determination of the ammonia formed using the pyridine-pyrazolone reagent. Part II of this dissertation includes proposed procedures for the determination of soluble and insoluble nitrogen in steels as well as for total nitrogen in soils and ammonia in soil extracts, The results of 23 steel analyses shows the applicability of the pyridine-pyrazolone reaction to this type of analysis. The in-ability to obtain reliably analysed soil samples has prevented a good study of the accuracy of this method as applied to soils. However, good precision has indicated that the method should be very applicable to soil analysis.
Degree
Ph.D.
Subject Area
Chemistry
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