Collisions of DCl with pure and salty glycerol: enhancement of interfacial D --> H exchange by dissolved NaI.
The fate of DCl molecules striking pure glycerol and a 2.6 M NaI-glycerol solution is investigated using scattering, uptake, and residence time measurements. We find that dissolved Na+ and I- ions alter every gas-liquid pathway from the moment of contact of DCl with the surface to its eventual emergence as HCl. In particular, the salt enhances both trapping-desorption of DCl and interfacial DCl --> HCl exchange at the expense of DCl entry into the bulk solution. The reduced entry and enhanced desorption of thermalized DCl molecules are interpreted by assuming that Na+ and I- ions bind to interfacial OH groups and tie up surface sites that would otherwise capture incoming DCl molecules. These ion-glycerol interactions may also be responsible for enhancing interfacial D --> H exchange by disrupting the interfacial hydrogen bond network that carries the newly formed H+ ion away from its Cl- pair. This disruption may increase the fraction of interfacial Cl- and H+ that recombine and desorb immediately as HCl before the ions separate and diffuse deeply into the bulk.
Muenter
Annabel H
AH
Department of Chemistry, University of Wisconsin--Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, USA.
DeZwaan
Jennifer L
JL
Nathanson
Gilbert M
GM
D003903:Deuterium / Q000737:chemistry*; D041961:Deuterium Exchange Measurement / Q000295:instrumentation / Q000379:methods*; D005990:Glycerol / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods; D012965:Sodium Chloride / Q000737:chemistry*; D012974:Sodium Iodide / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry
D012996:Solutions; D012965:Sodium Chloride; D006859:Hydrogen; D003903:Deuterium; D012974:Sodium Iodide; D005990:Glycerol