Reaction of Methanesulfonic Acid with Multifunctional Amines Used in Carbon Capture and Storage Technologies

VÉRONIQUE PERRAUD, Patricia M. Morris, Cathy Wong, Paulus Bauer, Colleen Miller, James Smith, Barbara Finlayson-Pitts, University of California, Irvine

     Abstract Number: 125
     Working Group: Aerosol Chemistry

Abstract
Although new particle formation (NPF) constitutes an important process in air, there are large uncertainties regarding which species form the first nanoclusters. Acid-base reactions are known to generate new particles, with methanesulfonic acid (MSA) formed from the photooxidation of biogenic organosulfur compounds becoming more important with time relative to sulfuric acid as fossil-fuel related sources of the latter decline. Simultaneously, the use of multifunctional amines in carbon capture and storage (CCS) technologies is expected to result in increased atmospheric concentrations of these bases. Experiments were conducted in a flow reactor coupled to a thermal desorption chemical ionization mass spectrometer (TDCIMS) to examine the NPF potential and the chemical composition of 4-20 nm nanoparticles derived from the reaction of MSA with monoethanolamine (MEA; NH₂(CH₂)₂OH), 4-aminobutanol (4AB; NH₂(CH₂)₄OH) and putrescine (PUT; NH₂(CH₂)₄NH₂). These reactions are even more efficient in nucleating particles than the simple alkylamines, exhibiting the highest nanoparticle formation rates measured to date in MSA systems. Water vapor had only a minimal enhancing effect, in contrast to simple alkylamine reactions. The acid-to-base ratio was close to unity in the range 4-20 nm. This contrasts with MSA reactions with methylamine (CH₃NH₂), where particles smaller than 9 nm were more acidic. The high NPF potential is attributed to the presence of an -OH group on the alkanolamines and an extra -NH₂ group for PUT that can participate in H-bonds within the nanoclusters. For comparison, experiments with the corresponding C2 and C4 alkylamines will also be presented. These results highlights that there is no "one-size-fits-all" regarding NPF from MSA reactions with amines, and illustrates the need for studies of more complex amines to fully characterize the NPF potential of this atmospherically relevant strong acid. This work also addresses the potential impact of amines used in CCS technologies.