Kinetic analysis of the process of melamine pyrophosphate synthesis

Abstract

This paper presents the results of investigations of the kinetics of the first degree of condensation of melamine orthophosphate to melamine pyrophosphate. The investigations were conducted under isothermal conditions and at constant rate of sample heating. The effects of sample mass and heating rate on the kinetic parameters of the process were determined. The activation energy of the process was determined using the approximate Kissinger method and the isoconversional Kissinger–Akahira–Sunose method. A complete analysis of the process was conducted to establish a kinetic model and to determine the activation energy and the value of the pre-exponential factor. It was found that in the initial period of the conversion (up to the value of ca. 0.20), the limiting stage of the process is chemical reaction (first-order reaction model—Mampel F1 equation). At conversion values α above 0.2, the reaction is described by Avrami–Erofeev A2 model.