(420a) Rational Synthesis, Characterization, and Reaction Screening of Alkali-Modified Hopcalite: Employing a Total Oxidation Catalyst for a Partial Oxidation Process

Hopcalite (copper manganese mixed metal oxide) has been used since the 1920s as a total oxidation catalyst for removal of CO as well as VOCs. Modern studies have attributed its high reactivity to the following lattice redox reaction: Cu(II) + Mn(III) Cu(I) + Mn(IV) Hopcalite exhibits high reactivity in its amorphous state, while increased crystallinity of the catalyst is generally associated with a sizeable decline in activity and surface area. This predictable lessening of hopcalite activity was exploited to optimize the catalyst's efficacy for partial oxidation reactions such as propylene epoxidation, using a rational synthesis and reaction screening approach. Moreover, alkali metal dopants were employed to tune the catalyst surface acidity to achieve maximum product selectivity. Catalysts were synthesized via gel combustion synthesis (GCS), and then screened for activity and selectivity using differential microreactors and on-line gas chromatography (GC). Catalysts of interest were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and BET surface area analysis.