Hydrogenation of High-vinyl Polybutadiene

Hydrogenation of High-vinyl Polybutadiene J.S. Parent

Olefin Hydrogenation Catalyzed by RhCl(PPh3)3 J.S. Parent

Modeling - Not Just for Beautiful People • Using our proposed catalytic mechanism, we can derive a design equation which expresses the hydrogenation rate as a function of process conditions. • This expression can be used to test the mechanism against experimental data • Fitting the expression to the data can yield a model of the reaction for use in process design and control • We will apply the “hydride” pathway as opposed to the “olefin” pathway. 1 K1 K2 K3 2 3 5 r.d.s. k4 irreversible 4 J.S. Parent

Modeling RhCl(PPh3)3 Catalyzed Olefin Hydrogenation • The rate of hydrogenation, as defined by the mechanism, is that of the rate determining step, r4: • Therefore, the reaction rate is: • However, this is not a useful design equation, given that the concentration of RhClH2(C=C)(PPh3)2 cannot be measured. • Treating the mechanism as a sequence of elementary reactions, we can express the reaction rate as: J.S. Parent

Modeling RhCl(PPh3)3 Catalyzed Olefin Hydrogenation • We now have an equation that represents the reaction rate as a function of the process conditions. A simplified form is consistent with experimental data: • If the reaction is run under constant pressure and kinetic control (as opposed to mass transfer limited) we expect the rate of olefin hydrogenation to be: • where: J.S. Parent

Hydrogenation of High-vinyl Polybutadiene