Interactions between atmospherically relevant molecules and sulfuric acid: Heterogeneous chemistry, uptake, and implications for the upper troposphere

The discovery of the ozone hole has led to the investigation of heterogeneous chemistry in the upper atmosphere. In this thesis, the interactions of acetone, 2-methyl-3-buten-2-ol, isoprene, methanol, formic acid, and water with sulfuric acid were explored. Both liquid and solid sulfuric acid solutions were synthesized in situ ranging in concentration from 35--96 weight percent and in temperature from 100--400 K. The solutions were ultrathin (0.003--0.05 mum) which makes reflection absorption infrared spectroscopy (RAIRS) a surface sensitive tool. This allows surface chemistry to be differentiated from bulk chemistry. Infrared spectroscopy was used to identify reaction products when the sulfuric acid solutions were exposed to probe molecules. Two mass spectrometric techniques were also used; temperature programmed desorption and uptake measurements. The mass spectrometry experiments provided kinetic information as well as product identification during the interactions between the probe molecules and sulfuric acid solutions.;Acetone and 2-methyl-3-buten-2-ol were found to react with sulfuric acid solutions and the reactions were dependent on temperature and sulfuric acid concetration. Acetone reacted stepwise through a second order mechanism to form mesityl oxide followed by trimethylbenzene. 2-Methyl-3-buten-2-ol was dehydrated through a first order mechanism to form isoprene. Since acetone reacted through a second order process, it was determined its solubility in sulfuric acid was not large enough to create a sink for acetone. However, since 2-methyl-3-buten-2-ol reacted through a first order process, its presence may affect the chemistry of the upper troposphere.