Hydrogen-Bond Breaking and Proton Exchange in Collisions of
Gaseous Formic Acid with Liquid Sulfuric Acid
Jane K. Klassen
*
and
Gilbert M. Nathanson
Gas-liquid scattering experiments provide direct observations of
the fate of hydrogen-bonding molecules striking the surfaces of acidic
liquids. Collisions of gaseous formic acid with concentrated sulfuric
acid show that impinging monomers (HCOOH and DCOOD) scatter
inelastically from the interface or become trapped by surface
H2SO4. Most trapped DCOOD molecules undergo
proton exchange before desorbing from the acid, indicating that
gas-surface accommodation almost always leads to reaction with
H2SO4 molecules. This proton transfer is not
inhibited by dimerization of the formic acid: The dimers readily
undergo intramolecular hydrogen bond cleavage and D-H exchange before
desorbing from the acid.
Department of Chemistry, University of Wisconsin, 1101 University
Avenue, Madison, WI 53706, USA.
*
Present address: Molecular Physics Laboratory, SRI International,
Menlo Park, CA 94025, USA.
To whom correspondence should be addressed.
