Model Experiment of Thermal Runaway Reactions Using the Aluminum-Hydrochloric Acid Reaction

A laboratory exercise for the education of students about thermal runaway reactions based on the reaction between aluminum and hydrochloric acid as a model reaction is proposed. In the introductory part of the exercise, the induction period and subsequent thermal runaway behavior are evaluated via a simple observation of hydrogen gas evolution and measurement of the temperature, which also provide basic information on the mechanistic features of the thermal runaway reaction. The exercise also includes PC aided thermometric measurements of the reaction and kinetic analysis of the induction period. The initiation time of the thermal runaway behavior under certain reaction conditions is calculated using the kinetic parameters determined experimentally by the students, The laboratory exercise provides a fundamental understanding of the mechanistic features of a thermal runaway reaction, recognition of the need for adopting safety measures when performing chemical reactions, and experience of using kinetic analysis for safety assessment.