The impact of water vapor on the OH reactivity toward CH3CHO at ultra-low temperatures (21.7–135.0 K): Experiments and theory

• Published in: The Journal of chemical physics Vol. 155; no. 3; pp. 034306 - 34319
• Main Authors: Neeman, E. M., González, D., Blázquez, S., Ballesteros, B., Canosa, A., Antiñolo, M., Vereecken, L., Albaladejo, J., Jiménez, E.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 21.07.2021
• Subjects: Acetaldehyde; Hydrogen bonding; Low temperature; Organic compounds; Physics; Reactivity; Water vapor; Catalytic effects; Gas-phase reactivity; Ultra low temperatures; Acetaldehyde reaction; Water vapor; Role of water; Hydrogen-bonded complexes; CRESU; Acetaldehyde; OH reactivity; Hydrogen bonds; Molecular physics; Laval nozzles
• ISSN: 0021-9606; 1089-7690; 1089-7690
• DOI: 10.1063/5.0054859

The role of water vapor (H2O) and its hydrogen-bonded complexes in the gas-phase reactivity of organic compounds with hydroxyl (OH) radicals has been the subject of many recent studies. Contradictory effects have been reported at temperatures between 200 and 400 K. For the OH + acetaldehyde reaction, a slight catalytic effect of H2O was previously reported at temperatures between 60 and 118 K. In this work, we used Laval nozzle expansions to reinvestigate the impact of H2O on the OH-reactivity with acetaldehyde between 21.7 and 135.0 K. The results of this comprehensive study demonstrate that water, instead, slows down the reaction by factors of ∼3 (21.7 K) and ∼2 (36.2–89.5 K), and almost no effect of added H2O was observed at 135.0 K.