Nonisothermal kinetic studies III: rapid nonisothermal-isothermal method for stability prediction

A continuous nonisothermal-isothermal method for stability prediction was developed. The approach yields all necessary parameters for prediction, including reaction order. The experimental procedure involves changing the temperature of the samples being studied until degradation is rapid enough to proceed at a convenient isothermal rate for a sufficient number of half-lives with adequate analytical sensitivity so that the reaction order can be unambiguously determined. The analytical information obtained during the nonisothermal and isothermal portions of the experiment is utilized without curve matching in calculating the activation energy and determining the reaction order, reaction rate, and stability prediction at any desired temperature. Model experiments include the acid-catalyzed hydrolysis of acetylcholine bromide and the inversion of sucrose.