Question

There are a class of reactions known as runaway reactions—reactions whose rate continually increases that are essentially caused by an uncontrolled feedback loop. Such reactions can lead to explosions if left unchecked. Explain, using what you know about thermodynamics and have learned about chemical kinetics so far, how a runaway reaction might occur.

Answer 1

Runaway reactions (also called thermal explosions) are the result of the loss of thermal control in a vessel undergoing a strong exothermic process.

Runaway reactions occur in situations where there is an exponential increase in the temperature inside the vessel so that the rate of heat generation becomes faster than the rate of heat removal/loss, with a consequent accumulation of heat and acceleration of the reaction rate. This event is more frequent for batch and semi-batch chemical processes, in which heat accumulation is more likely to occur.