Jean M. Andino

Computational and experimental study of the interactions between ionic liquids and volatile organic compounds

Computational chemistry calculations were performed to investigate the interactions of ionic liquids with different classes of volatile organic compounds (VOCs), including alcohols, aldehydes, ketones, alkanes, alkenes, alkynes and aromatic compounds. At least one VOC was studied to represent each class. Initially, 1-butyl-3-methylimindazolium chloride (abbreviated as C(4)mimCl) was used as the test ionic liquid compound. Calculated interaction lengths between atoms in the ionic liquid and the VOC tested as well as thermodynamic data suggest that C(4)mimCl preferentially interacts with alcohols as compared to other classes of volatile organic compounds. The interactions of methanol with different kinds of ionic liquids, specifically 1-butyl-3-methylimidazolium bromine (C(4)mimBr) and 1-butyl-3-methylimidazolium tetrafluoroborate (C(4)mimBF(4)) were also studied. In comparing C(4)mimCl, C(4)mimBr, and C(4)mimBF(4), the computational results suggest that C(4)mimCl is more likely to interact with methanol. Laboratory experiments were performed to provide further evidence for the interaction between C(4)mimCl and different classes of VOCs. Fourier transform infrared spectroscopy was used to probe the ionic liquid surface before and after exposure to the VOCs that were tested. New spectral features were detected after exposure of C(4)mimCl to various alcohols. The new features are characteristic of the alcohols tested. No new IR features were detected after exposure of the C(4)mimCl to the aldehyde, ketone, alkane, alkene, alkyne or aromatic compounds studied. In addition, after exposing the C(4)mimCl to a multi-component mixture of various classes of compounds (including an alcohol), the only new peaks that were detected were characteristic of the alcohol that was tested. These experimental results demonstrated that C(4)mimCl is selective to alcohols, even in complex mixtures. The findings in this work provide information for future gas-phase alcohol sensor design.

Chapter 14 - Tropospheric Chemistry of Aromatic Compounds Emitted from Anthropogenic Sources

Abstract The kinetics and mechanisms associated with the atmospheric photooxidation of aromatic compounds emitted from anthropogenic sources are of seminal importance in the chemistry of the urban and regional atmosphere. Aromatic compounds readily react with hydroxyl radicals to lead to ozone and aerosol formation. However, over the years, difficulties have existed in unambiguously identifying the stable species formed. Thus, only 60–70% of the reacted carbon has been fully accounted for. This article summarizes the major advances that have been made towards elucidating the atmospheric chemistry of anthropogenic aromatic hydrocarbons using computational chemistry. In addition, the computational data are compared to experimental data, and areas for future advances in the communitys understanding of aromatic reactions through the use of computational chemistry calculations are discussed.