This Demonstration illustrates the dynamics of two irreversible consecutive reactions,

, the first exothermic, the second endothermic, in a continuous stirred-tank reactor. The dimensionless equations for this system [1] are

where

,

, are the concentrations and

is the temperature,

is the Damköhler number,

is the activation energy,

is the ratio of the two rate constants,

is the ratio of activation energies,

is the heat transfer coefficient,

is the coolant temperature,

is the adiabatic temperature rise, and

is the ratio of enthalpies of reaction. The equations are solved with

and initial conditions

. As the heat transfer coefficient

is increased, the trajectories change from damped oscillations leading to a steady state to periodic, then to chaotic oscillations; further increases in β lead to damped oscillations and finally to an asymptotic approach to equilibrium.