Applications of kinetic methods in non-aqueous catalytic thermometric titrimetry. Part I. Evaluation of acetylation, α-methylstyrene and acrylonitrile indicator systems

Abstract

Kinetic methods, based on the measurement of the rates of reaction of reagent systems originally developed as thermometric indicators, may be used as a method to determine perchloric acid, potassium hydroxide and quinoline in microgram amounts. The reaction rate is measured by the initial slope of the temperature-time graph recorded when the sample compound is added to the reagent mixture. Perchloric acid is determined using both acetylation and α-methylstyrene indicator systems, and potassium hydroxide is determined with the acrylonitrile reagent. Quinoline is determined on mixtures of quinoline and an excess of perchloric acid using the acetylation indicator reaction. The rate of the acrylonitrile reaction is influenced significantly by the presence of dimethyl sulphoxide, which is used to increase the sensitivity of the method. In the α-methylstyrene reaction, the induction time before the reaction commences is also used to measure the catalyst concentration.