Dimerization reactions of ethylene to butene-l which take place in a continuously stirred tank reactor with recycle suffer from serious temperature runaway. Therefore, it is essential to control the dimerization reactor temperature to secure safe plant operation and to deliver good quality product. It is also desirable to maintain optimal operation of high ethylene conversion and desired butene-l yield in the face of plant upsets. The objective of this paper is, thus, to study the simulated implementation of standard proportional-integral (PI) control and linear model predictive control (MPC) for temperature stabilization of such a reactor to maintain favorable ethylene conversion and butene-l yield conditions. The mathematical model used in the simulations is developed by the author＇s research group (Trabzoni, 1998). The simulation results revealed the possibility of stabilizing such a reactor by both control algorithms. However, careful tuning of the parameters of these controllers is necessary, without which very aggressive or even unstable closed-loop performance will be obtained.