Molecular Beam Studies of Reactions of Protic Gases with Bare and Surfactant-Coated Sulfuric Acid
Abstract
Gas-liquid scattering experiments were used to investigate the uptake of HCl and HBr, the evaporation of water, and the hydrolysis of N2O5 in sulfuric acid coated with the soluble surfactants n-butanol and n-hexanol under atmospheric conditions. The experiments show that HCl and HBr uptake is enhanced by butanol and hexanol films, water evaporation is unimpeded, and N2O5 hydrolysis is reduced by twofold. This reduction likely occurs because N2O5 is a large molecule whose transport is impeded by the butyl and hexyl chains covering the acid surface. In contrast, HCl and HBr uptake is enhanced because they are smaller molecules that penetrate through the alkyl chains and dissociate by protonating the OH groups of interfacial butanol and hexanol molecules. The hydrolysis of N2O5 is the most important heterogeneous reaction in the atmosphere governing the depletion of ozone. The results suggest that this hydrolysis is overestimated in regions of the upper troposphere where small organic surfactants are present in high enough concentration to coat the surface of sulfuric acid aerosols.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 30, 2007
- Accession Number
- ADA469730
Entities
People
- Gilbert M. Nathanson