Dynamics of continuous isobutylene cationic polymerizations

Abstract

Polyisobutylene can be produced in either continuous cationic precipitation or solution polymerization reactors. It is known that the open-loop behavior of polymerization reactors may be very complex and may lead to oscillatory behavior, which is usually caused by thermal positive feedback (due to the large heats of reaction of polymerization reactions) and high viscosity effects (such as the gel effect in radical polymerization reactors and the decrease of heat transfer coefficients at high polymer concentrations). Oscillatory behavior may be observed in industrial isobutylene reactors, and it is intended to know whether these oscillations are inherent to the kinetic mechanism. Based on published experimental data, mathematical models are developed for both solution and precipitation processes. Steady-state solutions are calculated and steady-state stability is analyzed. Dynamic simulations and stability results reveal that only single stable steady-state solutions are possible for such reactors at usual operation conditions, which means that oscillatory behavior is not intrinsic to the reaction mechanism. © 1996 Wiley & Sons, Inc.