Work

Carbon Atom Reactivity with Amorphous Solid Water: H2O-Catalyzed Formation of H2CO

Year: 2021

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide We report new computational and experimental evidence of an efficient and astrochemically relevant formation route to formaldehyde (H 2 CO). This simplest carbonylic compound is central to the formation of complex organics in cold interstellar clouds and is generally regarded to be formed by the hydrogenation of solid-state carbon monoxide. We demonstrate H 2 CO formation via the reaction of carbon atoms with amorphous solid water. Crucial to our proposed mechanism is a concerted proton transfer catalyzed by the water hydrogen bonding network. Consequently, the reactions 3 C + H 2 O → 3 HCOH and 1 HCOH → 1 H 2 CO can take place with low or without barriers, contrary to the high-barrier traditional internal hydrogen migration. These low barriers (or the absence thereof) explain the very small kinetic isotope effect in our experiments when comparing the formation of H 2 CO to D 2 CO. Our results reconcile the disagreement found in the literature on the reaction route C + H 2 O → H 2 CO.

Source: The Journal of Physical Chemistry Letters

DOI: 10.1021/acs.jpclett.1c02760