Kinetics of deactivation of Re₂O₇‐Al₂O₃ metathesis catalyst

Abstract

The deactivation of 9% Rez07-Al203 catalyst during the metathesis of propene is investigated. Based on integral kinetic measurements and assuming separable deactivation kinetics, a deactivation rate equation has been developed which fits the experimental results well.

Tandem Heterogeneous Catalysis for Polyethylene Depolymerization via an Olefin-Intermediate Process

“…The postreaction catalyst was significantly darker in color as compared to the starting material (Figure S6) and showed a 49% reduction in reactive surface area (on a dehydrogenation catalyst basis) compared with the fresh catalyst (Table S1), suggesting carbonaceous deposits did reduce the available active surface area. Additionally, it is also possible that the active sites of the rhenium olefin metathesis catalyst deactivate, because this catalyst is known to decompose over time as well. − Regardless, the total recovered linear alkane products is greater than the consumed n -eicosane reactant (Figure b), which is expected, because the solvent is a reactant in this chemistry. Thus, a mass balance of products and residual reactants is greater than unity, because some of the carbon from the products originates from the solvent.…”

“…Noble metals such as Pt are well-known heterogeneous catalysts for C–H activation . However, nonoxidative alkane dehydrogenation is an equilibrium-limited reaction that requires temperatures well above 400 °C and low pressures to achieve high alkane conversions, while the active sites of the Re-based heterogeneous olefin metathesis catalysts are unstable above 100 °C. − Thus, a challenge for this system is how to kinetically couple both reactions such that the system features both high activity and stability.…”