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Abstract To disentangle the factors controlling the rates of accelerated reactions in droplets, we used mass spectrometry to study the Katritzky transamination in levitated Leidenfrost droplets of different yet constant volumes over a range of concentrations while holding concentration constant by adding back the evaporated solvent. The set of concentration and droplet volume data indicates that the reaction rate in the surface region is much higher than that in the interior. These same effects of concentration and volume were also seen in bulk solutions. Three pyrylium reagents with different surface activity showed differences in transamination reactivity. The conclusion is drawn that reactions with surface‐active reactants are subject to greater acceleration, as seen particularly at lower concentrations in systems of higher surface‐to‐volume ratios. These results highlight the key role that air‐solution interfaces play in Katritzky reaction acceleration. They are also consistent with the view that reaction‐increased rate constant is at least in part due to limited solvation of reagents at the interface.
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Reaction Acceleration Promoted by Partial Solvation at the Gas/Solution Interface
Abstract The kinetics of organic reactions of different types in microvolumes (droplets, thin films, and sealed tubes) show effects of gas/solution interfacial area, reaction molecularity and solvent polarity. Partial solvation at the gas/solution interface is a major contributor to the 104‐fold reaction acceleration seen in bimolecular but not unimolecular reactions in microdroplets. Reaction acceleration can be used to manipulate selectivity by solvent choice.
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- Award ID(s):
- 1905087
- PAR ID:
- 10306912
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ChemPlusChem
- Volume:
- 86
- Issue:
- 10
- ISSN:
- 2192-6506
- Format(s):
- Medium: X Size: p. 1362-1365
- Size(s):
- p. 1362-1365
- Sponsoring Org:
- National Science Foundation
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