AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Kinetics and pH Dependence of Aqueous-phase Reactions of Glycolaldehyde with Glycine, Ammonium Sulfate, and Methylamine
ALYSSA RODRIGUEZ, Michael Symons, Alexia De Loera, Melissa Galloway, David De Haan, University of San Diego
Abstract Number: 663 Working Group: Aerosol Chemistry
Abstract Glycolaldehyde is produced by biomass burning and isoprene oxidation, and is a common atmospheric aldehyde. Its photooxidation in aqueous droplets and aerosol has been identified as a potentially important SOA source. Its aqueous phase reactions with atmospheric amino acids and amines may also be a source of SOA and brown carbon material. These reaction rates can be measured by proton NMR in 0.5 M D2O solutions. Aqueous reactions of glycolaldehyde with glycine, ammonium sulfate, or methylamine were studied over the pH range 3-7. After 11 hour reactions in a 400 MHz NMR spectrometer, signals were converted to concentrations using MestReNOVA software and reaction rates were extracted from both reactant signals. Reaction rates (and browning) increased with pH, as expected. Glycolaldehyde loss rates were typically far in excess of amine loss rates, consistent with amine-catalyzed aldol condensations being the dominant reaction pathway. Aromatic products were observed in the NMR spectrum.