(750g) Low-Temperature Thermal Catalytic and Electrocatalytic Approaches for Liquid-Phase Light Alkane Upgrading

The growth of natural gas supplies, as well as ever-present environmental concerns, have led to efforts to develop catalytic technologies compatible with a more diverse portfolio of feedstocks for chemical production. The concept of distributed chemical manufacturing, which describes networks of production facilities operating at reduced scale and nearby to resources and end-use applications, is closely related – unconventional feedstock resources are often stranded, and production opportunities for renewable energy, proposed to drive the relevant chemical transformations, are not uniformly geographically distributed. In order to promote greater synthesis distribution, it is essential to explore the behavior of liquid-phase catalytic systems in mild conditions – especially near room temperature and atmospheric pressure. A notable example is the advancement of electrochemical processes for O₂ reduction in water to H₂O₂, a powerful, selective oxidant of hydrocarbons and a chemical with numerous industrial applications.

This presentation will describe efforts toward understanding the oxidative functionalization of light alkanes in mild, aqueous conditions to oxygenates, including alcohols, aldehydes, and acids. Quantitative catalysis results will be presented for low temperature and pressure liquid-phase transformations of ethane and methane, with and without the application of electric potential. Air, water, and H₂O₂ (produced electrocatalytically from air and water) have been studied as oxidants, and the associated results will be contrasted. The accompanying Figure provides (left) quantification of products associated with the room-temperature and atmospheric-pressure partial oxidation of ethane in water with dispersed AuPd nanoparticle catalysts (manuscript submitted). These data are representative of one area that will be discussed – product distributions and conversions with increasing reaction times in batch conditions. Pressure and temperature dependence will also be presented. The Figure also shows (right) representative oxygen reduction reactions with detected H₂O₂, used for benchmarking thermal and electrochemical catalysts in standard conditions for H₂O₂ production and decomposition (not shown).