Ilya Prigogine and René Lefever invented this mathematical model in 1968. They worked at a university in Brussels, which gives the model its unique name. They wanted to show how simple chemical steps could create complex timing patterns.
A normal reaction moves straight toward a final resting state called equilibrium. The Brusselator model describes a system that gets stuck in an endless loop instead. The model uses two starting chemicals and two temporary intermediate chemicals.
An intermediate is a temporary substance made during the middle of a reaction. One intermediate chemical in this model actually helps create more of itself. Chemists refer to this special self-making process as an autocatalytic feedback loop.
As this first chemical builds up, it suddenly turns into the second intermediate chemical. This sudden shift causes the amounts of both chemicals to swing wildly. When the starting chemicals reach a specific critical amount, the whole system changes behavior.
It enters a stable state where the chemical amounts endlessly rise and fall. A common student mistake is thinking this process requires adding chemicals at a steady rhythm. The chemical rhythm actually comes entirely from the internal steps of the reaction itself. This important model helps scientists understand biological clocks and animal coat patterns.