Mechanism and kinetics in catalytic hydrocracking of polystyrene in solution

A mechanism for polystyrene hydrocracking on a bifunctional Pt/H-Beta catalyst has been proposed. The mechanism consists of three steps for polymer degradation: initiation, propagation and termination, and an additional step for transformation of aromatics, direct product of polystyrene degradation, into other hydrocarbons. The most important reactions in the last step are hydrogenation–dehydrogenation and ring opening reactions, to produce naphthenics, paraffins and isoparaffins, with higher added value as fuels. Finally, degradation of polystyrene by catalytic hydrocracking has been described by means of continuous distribution kinetics, which allows for modelling of the evolution of polymer molecular size and conversion with reaction time, and estimation of kinetic parameters associated to catalyst characteristics when working in the kinetic regime.