Bioinspired oxidation of methane via caged heme diirion catalysts – BOOM
Producing chemicals and liquid fuels (methanol) from a wasted greenhouse gas (methane), is highly lucrative and an ecological priority. Conceptually, the direct methane-to-methanol oxidation is an ideal “waste-to-wealth” route to both trap CH4 being flared worldwide and fulfill the demand for the methanol liquid fuel. Despite decades of intensive research, the 100% atom-economy methane oxidation remain a bottleneck in catalysis. There are two major difficulties to this direct conversion: 1) The exceptional stability of methane C-H bonds, 2) The dissociation energy of methanol C-H bonds being significantly lower than in methane, it is thermodynamically arduous to obtain methanol as the single reaction product. The major challenge is to convert methane to methanol in a selective and sustainable fashion (cheap and eco-compatible catalysts, oxidants and solvents, low temperature).
To achieve this goal chemist might seek inspiration from nature, where soluble methane mono-oxygenase enzymes perform selective CH4 oxidation under physiological conditions, at a diiron active site. These ideal catalysts take advantage of their hydrophobic pocket, which controls methane recognition and methanol ejection. However, the state-of-the-art of bioinspired models hits serious problems when applied to methane oxidation. A key bottleneck is the lack of a second coordination sphere, resulting in non-selective catalysts (deep overoxidation of methanol).
In this project, a switch to the selective oxidation of methane is targeted. This goal will be reached by 1) building caged bioinspired diiron catalysts, 2) proving their superiority for simultaneous high methane conversion and methanol selectivity, and 3) optimizing the economic cost and recyclability of the catalysts. By bridging the fields of homo- / heterogeneous catalysis and supramolecular chemistry, BOOM will provide a practical and eco-compatible method to accomplish sustainable and selective methane to methanol conversion.
Monsieur Cédric Colomban (Centre national de la recherche scientifique)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
ISM2 Centre national de la recherche scientifique
Help of the ANR 205,004 euros
Beginning and duration of the scientific project: December 2022 - 48 Months