The mathematical modelling of a bench-scale batch reactor is presented. The formulation of the mass and heat balances leads to a set of algebraic-differential equations which, when solved, produce the temperature and concentration profiles as a function of time. Emphasis has been placed on a realistic description of such a reactor by incorporating an accurate representation of the heat effects, such as the heat taken by the reactor wall, heat losses, stirring power supply, heat of dilution, vortex influence on heat transfer area, and a model of the heating/cooling circuits as well as their controllers. To obtain the data necessary to simulate the dynamic behaviour of the reactor, a set of characterisation tests was carried out. Once the different parameters of the model were evaluated, some experiments were performed to compare with the predicted dynamic behaviour obtained with the simulator. These experiments invluded the heating/cooling dynamic behaviour with different fluids, and the neutralisation reaction between sodium hydroxide and hydrogen chloride.