Continuous partial oxidation of methane to methanol over Cu-SSZ-39 catalysts

Abstract

The direct conversion of methane to methanol using molecular oxygen as the oxidant is a grand challenge in the chemical sciences. Here we describe our efforts in using copper-exchanged SSZ-39 for this chemistry and show it is a promising material for this reaction. Testing in a continuous flow reactor at 225 °C, Cu-SSZ-39 showed superior activity for methane partial oxidation compared to Cu-SSZ-13 (site time yields of 26.9 ± 0.8 molCH3OH·molCu−1·h−1 *10−3 versus 13.2 molCH3OH·molCu−1·h−1 *10−3 respectively). A clear maximum in methanol productivity, both in terms of a mass catalyst basis and copper atom basis is observed for Cu-SSZ-39 at a Cu/Al ∼ 0.2. Running this reaction in the absence of oxygen over samples with a Cu/Al > 0.1 the reactivity is markedly lower than that in the presence of oxygen unlike what is observed in SSZ-13.